Identify Current Thinking On Leadership

Identify Current Thinking On Leadership In the last few decade it has been found the relation between the effective leadership style and culture is very critical. For example, the multinational organization like Daimler Chrysler, IBM forces their HR and other department to recognize the culture limitation of the organization and the leadership style. A number of researchers have done their work on understanding the impact of culture on the leadership practices and vice versa (ea.,Gessner, Arnold, Mobley, 1999; Hofstede,1991;house, Hanges, Javidan, Dorfman, Gupta, (2004) Leslie Van Velsor,1998). International literature has been reviewed and the generalization of leadership theories being assessed by Dorfmen(2004) and chemers( 1997), both of them found out some mixed result, yet some behavioral like supportive leadership and transnational leadership style result similar across the culture. While the cultural consequences has been observed with directive leadership. From the last fifty years the thinking patterns about the leadership, whether in a board room or in communities has been heavily influenced by mode of heroic leadership. Traditionally the idea about the leadership was considered up to skills, qualities and behavior of individual who forces and influences other to take action and achieve the given task or common goal by using their position and power. But later on as the more studied and research on the topic has been done it has been found that this way of thinking is a mere part of leadership theory and it fail to explain the leadership as a process build by relationship that are dynamic, fluid and non-directive in nature. Leadership understanding is a unique process that requires to think very differently about the changes had taken place and how we work others individual and groups. To understand the Current leadership style and thinking it is necessary to understand the history about it. How it is developed or evolved. Unless by understanding them it is difficult to comment on their evaluation. This paper provides a brief summary of the different style leadership and their relation with cultural implication. A Brief History about Leadership Great Man theories: These theories are based on belief that leaders have some exceptional born qualities in them. Here the term man is used intentionally as it has been observed the leaders of primitive time are male whether from military, politics or king etc. these lead the next school of trait theories. Trait theories: This theory argues that leaders have some common trait among them. It can be said according this theory all leaders are having some common ingredient. Though this theory also fail to explain how the leader e.g. Margaret Thatcher or Winston Churchill with these characteristics fail to perform as a leader. While some despite having those trait became a successful leader. Behavioral theories: These theories are developed to explain the failure of Trait theory, the initial work to develop these theories has been started in 1940 to till 1960. These theories are based on leadership behavior rather than their trait. What leaders do rather than what the quality they have? Different style and pattern of behavior of leaders are analyzed and observed. This is one of the most interested area for practiced managers. (Arnold, Mobley, 1999; Hofstede,1991) Situational Leadership theories: This theory argues that different situation demand different type leadership style. Sometime it requires being autocratic, some time democratic some time participative. It recognizes the demand of situation and a leadership style has to be changed according to situation. It also suggests a different type of leadership style is required within the same organization at different level. Contingency Theory: It can be said it is the advancement of the Situational Leadership theory. Its focus on identifying the situational variable which predict the best suitable style of leadership style for the given situation. Transactional Theory: This theory emphasis the relation between the leader and the follower. It focuses on the mutual benefit and common interest. According to this theory, the leader commits something in return to his/her follower for favoring or following him or her. It is more or less give and take style, hence known as transactional theory as name suggest no bonding after the deliverable. Transformational Theory: The motto here is to change role of leadership by transformation, by motivation, by education, by emotion etc. New leadership theory Relates to Charismatic, Visionary, Transformational. In the 1980s, the new definition of a leader has been given by using the above word. Learning organizations and distributed leadership: All of the theories discussed above take an individualistic perspective of a leader, in current practices a new school of thought is becoming more popular known as dispersed leadership. This approach tells us to distribute leadership spread it across the organization, societies, geography, and politics. This approach sees leadership as a process that is diffused through the cultures, organization, societies rather than laying a few handful of people designated as leader. The locus has been shifted from developing a leader to developing leaderful organization or societies. It is evident from the above theory that none of the theory explains leadership comprehensively. The Distributed leadership practice fight with the idea of difficult time demand a transformational and charismatic leader. To satisfy this need there are a number of themes that are important for systematic analysis of leadership are context, perceived leadership, behavioral requirements, development methods and capabilities.( Dorfmen, 2004;chemers, 1997) Context: A leadership cannot be discussed in isolation it has some external environment some extraneous and variable factor. By considering this factor, a leadership style has to be evolved or developed. For example, the requirement of a government office job is quite different from those required private sector jobs. Alternatively, the requirement for a job academician or researcher the qualities might be different which required for a sales job. Perceived Need: A lot of researches in 1960s suggest that the context lead to the need. However from the late 1940s there has been a technical and social aspect to analysis of organization hence it is not surprising to see that some researchers argument over the ideological aspect to the perceived need for leadership. For example Top management do not buy the idea that people follow them because they have authorityà ¢Ã¢â€š ¬Ã‚ ¦ they like to feel that they lead because they have the quality to lead (Miller and Form 1964) By putting aside the need of the top manager whether social or psychological and going by the perspective of stakeholders and other staff, the perceived leadership requirement for the situation depend upon the expectation of the individual and group involved as well as from the reality of situation too. It has been found the expectation of people and group themselves be a reflection of the existing belief, culture, and norms. For example leading a service centre is different from leading a audit team. The group members expectation from the leader is different in both the group due the culture, knowledge, belief and practice both the group follow. Hence affect the effective leadership style. Behavioral Requirements and competencies The leaders require having some behavioral requirement and competencies. Many models have been suggested to define these requirement and competencies. Though these three are common among them. Cognitive: Drawing the big picture and making direction to modify it. Making change happen: This quality talk about motivational skills and get the work done from the subordinate Inter-organizational: To work with the college and partner and create a healthy environment Current Thinking Transformational Leadership (TL) and Emotional Intelligence (EI) are the most popular views in the current moment. Though it cannot be suggested that they are right because they are popular rather they are right because indeed a lot of research and scholars work has been done on both the views and they explain the leadership up to a great extent in current scenario. (Miller and Forum 1964) Transformational Leadership Transformational leadership is more than transaction leadership. Anderson, TD(1992) talk transforming leadership is about vision, planning, communication and creative action which has a positive and motivating effect on the group and individual under a clear set of values and beliefs, to accomplish a desired measureable goals. This transforming moves similarly impact on the personal development and the productivity or corporation. It can be said the heart of transformational leadership is inspiring vision. The transformational leaders motivate people to achieve beyond expectation for the interest of group, corporation, and society on the verse of personal interest. TL makes a positive impact on morality, empowerment and motivation of an individual and group. (Routledge, 2006; Transformational Leadership; pg 34-38) The main characteristics of a TL is discussed by various leaders is highlighted below. Charismatic: Charismatic is a metaphor like a role model whom other follow and strive to emulate those characters who align the other people around a common goal and purpose. Inspirational: This word talks about the leadership quality, which provides the meaning and optimism about the common goal and its attainability. Intellectually Stimulating: This quality of the leader encourage the follower to develop a leader within them and verify the basic assumption involved in a project and consider the problem from a unique and new perspectives. Individually considerate: This quality of leader explain how leader work in a team, work with their follower , find out their need, figured out their self interest and develop their potential and how to enhance their expectations. A study conducted by Tom Peters found that TL leaders in the public sector where they took off their interest from the financial, management issue and government out target have had to go. On the other hand it can be said great characters are likely to have great weaknesses too, which lead to hamper their position, their colleagues, their followers and their organizations too. Although the above stanza portray the negative image of a transactional leader, but it cant be generalized because in the last decade it has been observed TL has moved beyond the Great Leader to distributed leadership and has been became a more balanced towards recognizing the importance of good management. Here the emphasis is given on the result, the process, the practices and a continuous learning environment for an individual and the for the group too. (John Storey Michael Fullan; Leading a cultural change) Emotional Intelligence (EI) Daniel Goleman has researched and written about the term a lot. According to him this term and its application to leadership behaviors to neuroscience in a manner that correlate human thinking and feeling and explain how our right brain concurs over the left. Hence to be a emotionally intelligent leader it is prerequisite to be self aware and self managed. The term given to this awareness is personal competences. Goleman found in his research that people with high EI score are more successful than the people who have lower EI. The Youngsters who were low on Emotional intelligence were prone to criminology. Hence Goleman has proved EI is a consideration of leadership. The social completeness the most critical for a leader comes from the development of the persona competences. These talk about social awareness and relationship management. A set of competencies lead to emotional intelligence. These skill set give the power the of understanding the persons ability, control and monitor his or her emotion efficient and effectively and to read the others and then manage and influence the other emotional state (Caurdon, 1999; Goleman, 1998). Goleman explain it within five dimensions. The following are the set behavioral attributes of the each area. Self- awareness the key stone of emotional intelligence, it is the ability of any individual to recognize the feeling of him or her and is to make an actual self- assessment and self-confidence. Self- Management is the art of controlling the disruptive emotions and to controls the impulses. Keep maintain the standards of honesty and integrity, be comfortable with the novel approaches and ideas and take the responsibility of somebody else performance. Motivation is the ability of a leader to influence the other people to outperform or facilitate towards the common goal. It consists of achievement, commitment, initiative, and optimism. Empathy word describes how a leader involved in the feelings, perspectives, concern and needs of the other. How a leader understands the problem of follower and rectifies them. Social Skills are basic to emotional intelligence. They include the persona of a leader his ability to get the desirable response from the others by communicating or presenting his or her viewpoint in a manner that is to be accepted by individuals and societies, inspire the individual and groups, nurturing the relationship, and working towards the common goal by creating group synergy. Past decade we have seen many leaders having great EI got succeeded in their life. Though it has been a topic of debate among emotional and intelligence which quality is more important for a leader. It can be said these two qualities are not complementary for a leader rather than these are supplementary quality. These work together, because an emotional leader has to be intelligent too or an intelligent leader has to be emotionally intelligent too. Culture Culture can be defined as knowledge, belief, idea and behavior, shared attitude, values, goal, and practices, custom and ritual performed by any individual and group or societies. The meaning of culture has been changed with the passage of time and from context to context. In early eighteenth and nineteenth century in Europe culture is considered as the improvement in cultivation, in the same way it had various definition with time to time. These points can be said about the culture. (John Story and Michel Fullan) A phenomenon wave, which surround us Culture itself tells us how it is evolved and helps us to understand its creation, development, manipulation and management. A leadership cannot be defined in isolation without considering the cultural. To understand and an organization or society it is imperative to understand its culture. Culture is a combination of customs and rights. Good managers must know and understand the customs and rights. Each organization has their own set of belief and standard referred as culture. As an outsider approach to any organization he needs to understand the culture at first of the organization or society. It Consist of the language, customs, traditions, standards and values, published and publicly announced values, philosophy, rules in organization, group interaction, thinking pattern, paradigms and shared knowledge for socialization and symbols meanings. Leader must adopt and suit their style according to situation and culture in which they operate. For example what works in china may or may not be likely to work in Canada or France. One can be effective in Canada by humiliating the departmental store employee but thats not guarantee that it will be applicable to Japan and India. As different individual needs different treatment based upon their culture. If humiliated employee leave the organization hence it creates more difficulties for a leader as he need to hire another one train him hours and to tell him process and systems and it will take some time for the employee to get acquainted with the new organization. National Culture affects the leadership style due to that a leader cannot choose their style at their own wish. There are some societal constraints over that. For example in Korea a leader is expected to be caring about their follower while in the Arab a leader is who shows kindness and generosity without being asked is considered by other Arab as week. In Japan leaders are expected to be humble and participative in common forum. Consisting with the contingency approach, a leader need to adjust their working style according to the aspect the organization, industry and culture in which they operate. For example a manipulative or altercative style is compatible with high power distance, like Russia, Spain, Far East, Latin Countries and Spain. While a participative style is most likely to be associated with culture with low distance like Norway, Sweden, Denmark and Finland. Power distance ranking is a good indicator of employee willingness to accept of participative or autocratic leadership. (Globe Project) Conclusion No theory or model is able to explain and provide a satisfactory explanation of leadership. Indeed there is no common consensus on the meaning or definition of leadership among all theory and scholars in first place. Most of the theory is extension or improved version of the pervious theory or partial explanation of leadership within itself. Many theories are based on personal or even limited, biased research referring to particular philosophical or ideological points of view. As a researcher get the answer of the question as he or she asks. As per Yukis wide-ranging review of the leadership literature in 1989 most of the theories are conceptually weak and lack in strong empirical support. Numbers of empirical studies on leadership has been done but the result are most of the time are contradictory or inconclusive. A related shortcoming of the current leadership is the separation of tracks like cognitive, emotional, spirituality and behavioral aspects. None of the theories and model has been reviews except servant leadership theory address the spiritual element of peoples life. Some theory is superficial like research by the industrial society in 1996. Though its debatable whether leadership affects the culture or culture affect the leadership, as both are interrelated they cannot run in isolation of each other. A leader cannot be successful if he does not follow the culture norms. Or if the leader is so much powerful then he can spoil the culture and create a new society or culture. But history has proved even the government, king and leader who autocratic and tries to implement their ideas and thought without understanding the demand of society or culture fail to perform. Hence it is very imperative to be any leader to align their leadership style with the culture of particular society and what the time demand.

Nerve Conduction Physiology

Nerve Conduction Physiology BASIC PHYSIOLOGY OF NERVE CONDUCTION The neurons form the building blocks of the nervous system. The central nervous system (CNS) contains about 100 billion neurons. It also contains 10–50 times this number of glial cells. Neurons Neurons in the mammalian central nervous system come in many different shapes and sizes. Most of them have the same parts as a typical spinal motor neuron shown in Figure 2. Figure-2: Typical spinal motor neuron The cell body (soma) contains the nucleus and is the metabolic center of the neuron. Neurons have processes known as dendrites which extend outward from the cell body and arborize extensively. Particularly in the cerebral and cerebellar cortex, the small knobby projections over dendrites are called dendritic spines. The dendrites are the receptive part of the neuron. A typical neuron has long fibrous axon that originates from thickened area of the cell body, the axon of hillock. The first portion of the axon is called the initial segment. The axon divides into presynaptic terminals, each ending in a number of synaptic knobs which are also called terminal buttons or boutons. They contain granules or vesicles in which the synaptic transmitters secreted by the nerves are stored. The axonal process is responsible for transmission of propagated impulses to the nerve endings. Based on the number of processes that emanate from their cell body, neurons can be classified as unipolar, bipolar, and multipolar. Figure-3: Unipolar and bipolar neurons Figure-4: Multipolar neurons Glial cells: There are two major types of glial cells : microglia and macroglia. Microglia are scavenger cells they resemble tissue macrophages and remove debris resulting from injury, infection, and disease (eg, multiple sclerosis, AIDS-related dementia, Parkinson disease, and Alzheimer disease). Microglia arise from macrophages outside the nervous system and are physiologically and embryologically unrelated to other neural cell types. Glial cells continue to undergo cell division even in adults and their ability to proliferate is particularly noticeable after brain injury (eg, stroke). There are three types of macroglia: 1 Oligodendrocytes, 2 Schwann Cells, and 3 Astrocytes. Oligodendrocytes and Schwann cells form myelin around axons in the CNS and PNS , respectively. Astrocytes are of two subtypes. Fibrous astrocytes, which contain intermediate filaments, found primarily in white matter. Protoplasmic astrocytes are found in gray matter having granular cytoplasm. Both types of astrocytes send processes to blood vessels, where they induce capillaries forming the tight junctions making up the blood–brain barrier. They send processes enveloping synapses and surface of nerve cells. Protoplasmic astrocytes have a membrane potential varying with the external K+ concentration but they do not generate propagated potentials. They produce substances that are tropic to neurons, and they help maintain the appropriate concentration of ions and neurotransmitters by taking up K+ and the neurotransmitters glutamate and ÃŽ ³-aminobutyrate (GABA). The axons of many neurons are myelinated, that is, they acquire myelin sheath, a complex of protein lipid wrapped around axon. In the peripheral nervous system, when a Schwann cell wraps its membrane around an axon up to 100 times myelin is formed. The myelin is then compacted when the extracellular portions of a membrane protein called protein zero (P0) lock to the extracellular portions of P0 in the apposing membrane. The axon is covered by myelin sheath except at the ending and at the nodes of Ranvier, periodic 1-m constrictions that are about 1 mm apart (Barrett et al., 2012). In the myelinated neurons, the junction between the 2 Schwann cells is known as the node of Ranvier, where the axon remains uninsulated. The intermodal distance is the distance between the 2 nodes of Ranvier and depends upon the spacing of Schwann cells at the time of myelination. As there is no proliferation of Schwann cells later on, intermodal distance increases during the growth of nerve. Thus the fibe rs myelinated early have longer intermodal distance, larger diameter and wider spacing at the node of Ranvier. The nerve conduction velocity depends on the fiber diameter and intermodal distance. The larger the axon the thicker the myelin sheath and longer the internodal distance, the faster the conduction velocity. (Mishra Kalita, 2006). Not all neurons are myelinated; some are unmyelinated, that is, simply surrounded by Schwann cells without the wrapping of the Schwann cell membrane that produces myelin around the axon. Figure-5: Glial cells: A Oligodendrocyte, B Schwann Cell, C Astrocyte Most of the neurons are myelinated in the CNS of mammals,, but the cells that form the myelin are oligodendrocytes rather than Schwann cells. Unlike the Schwann cell, which forms the myelin between two nodes of Ranvier on a single neuron, oligodendrocytes emit multiple processes that form myelin on many neighboring axons. Generation and conduction of impulse in nerve cells Nerve cells have a low threshold for excitation responding to electrical, chemical, or mechanical stimulus. Two types of physicochemical disturbances are produced and these are the only electrical responses of neurons and other excitable tissues,. local, non propagated potentials; and propagated potentials, the action potentials (or nerve impulses) and they are the main language of the nervous system. They are produced by alterations in ion channels causing changes in the conduction of ions across the cell membrane. These electrical events are rapid, measured in milliseconds (ms); and the potential changes are small, being measured in millivolts (mV). The impulse is normally transmitted (conducted) along the axon to its termination. Conduction of nerve impulses is rapid but much slower than that of electricity. Conduction is an active process it is self-propagating , and the impulse moves at a constant amplitude and velocity. Resting membrane potential The resting membrane potential represents an equilibrium situation at which the driving force for the membrane-permeant ions down their concentration gradients across the membrane is equal and opposite to the driving force for these ions down their electrical gradients. In neurons, the concentration of K+ is much higher inside than outside the cell, while the reverse is the case for Na+. This concentration difference is established by the Na+K+ ATPase. In neurons, the resting membrane potential is usually about –70 mV, which is close to the equilibrium potential for K+. Action potential In response to a depolarizing stimulus, some of the voltage-gated Na+ channels become active, and when the threshold potential is reached, the voltage-gated Na+ channels overwhelm the K+ and other channels and an action potential results (a positive feedback loop). The membrane potential moves toward the equilibrium potential for Na+ (+60 mV) but does not reach it during the action potential, primarily because the increase in Na+ conductance is short-lived. The sodium ion channels rapidly get closed called the inactivated state .In addition, the direction of the electrical gradient for Na+ is reversed during the overshoot because the membrane potential is reversed, and this limits Na+ influx. A third factor producing repolarization is the opening of voltage-gated K+ channels. This opening is slower and more prolonged than the opening of the Na+ channels, and consequently, much of the increase in K+ conductance comes after the increase in Na+ conductance. The net movement of positive charge out of the cell due to K+ efflux at this time helps complete the process of repolarization. The slow return of the K+ channels to the closed state also explains the after-hyperpolarization, followed by a return to the resting membrane potential. Thus, voltage-gated K+ channels bring the action potential to an end and cause closure of their gates through a negative feedback process. Distribution of Ion Channels in Myelinated Neurons The spatial distribution of ion channels along the axon plays a key role in the initiation and regulation of the action potential. Voltage-gated Na+ channels are highly concentrated in the nodes of Ranvier and the initial segment in myelinated neurons. The initial segment and, in sensory neurons, the first node of Ranvier are the sites where impulses are normally generated, and the other nodes of Ranvier are the sites to which the impulses jump during saltatory conduction which is responsible for faster impulse conduction in myelinated neurons. The number of Na+ channels per square micrometer of membrane in myelinated mammalian neurons has been estimated to be 50–75 in the cell body, 350–500 in the initial segment, less than 25 on the surface of the myelin, 2000–12,000 at the nodes of Ranvier, and 20–75 at the axon terminals. Along the axons of unmyelinated neurons, the number is about 110. Electrogenesis of the Action Potential The nerve cell membrane is polarized at rest, with positive charges lined up along the outside of the membrane and negative charges along the inside. During the action potential, this polarity is abolished and for a brief period is actually reversed. Positive charges from the membrane ahead of and behind the action potential flow into the area of negativity represented by the action potential (current sink). By drawing off positive charges, this flow decreases the polarity of the membrane ahead of the action potential. Such electrotonic depolarization initiates a local response, and when the firing level is reached, a propagated response occurs that in turn electrotonically depolarizes the membrane in front of it. (Barrett et al., 2012) Figure-6: Propagation of Action Potential Action potential generated in axons is propagated to either direction from its site of origin. Intracellular current flows from the active zone where the inner cell membrane is positively charged compared to adjacent inactive membrane which is negatively charged. An opposing current flows through the extracellular fluid from the inactive to active region. This local current depolarizes the adjacent inactive regions, thus resulting in impulse propagation bidirectionally along the axon. The physiologic impulses, however, arise at one end of the axon i.e., the cell body or sensory terminal and are conducted only orthodromically. In pathological conditions, however, this order of conduction is not maintained. In the myelinated fibers, the conduction is much faster than the unmyelinated. In normal myelinated axons the impulse propagated by saltatory conduction. Saltatory conduction has been compared with a kangaroo travelling at speed. The action potential advance at near uniform velocity , but it is powered by discrete kicks of inward membrane current at the nodes of Ranvier. For rapid conduction, the intermodal distance should be great enough to maximize the jump of the action potential and reduce the loss of current at the node of Ranvier. In myelinated fibers the time required for the local current to excite the next node depends on the longitudinal resistance of the axoplasm, capacitance, and conductance of the intermodal membrane. With high value of these parameters, more current is dissipated before impulse reaches the next node. This results in longer time for the impulse to depolarize the adjacent node, which is responsible for the slower conduction. Myelin thickness is inversely related to internodal capacitance and conductance. Conduction velocity, therefore, increases with the increase in myelin to a certain point. In segmental demyelination or during remyelination, myelin sheath is thin, intermodal distance shorter, internodal conductance and capacitance is increased. These result in greater loss of local current before reaching the next node of Ranvier. The failure to activate the node of Ranvier results in conduction block. In case of a partial conduction, the impulse propagation is slowed due to longer time required by the dissipating current to generate an action potential. In segmental demyelination of smaller fibers the conduction may become continuous instead of saltatory. Impulse conduction in unmyelinated fibers occurs in a continuous manner which accounts for slower conduction velocity compared to saltatory conduction in myelinated fibers. The conduction velocity also slows down in focal compression, which may be due to demyelination and decrease in fiber diameter. (Mishra Kalita ,2006).The loss of myelin is associated with delayed or blocked conduction in the demyelinated axons. Normal conduction of action potentials relies on the insulating properties of myelin. Thus, defects in myelin can have major adverse neurological consequences. Loss of myelin leads to leakage of K+ through voltage-gated channels, hyperpolarization, and failure to conduct action potentials. Nerve conduction tests can detect slowed conduction in motor and sensory pathways. (Barrett et al., 2012) NERVE CONDUCTION STUDIES (NCS) The main indication of nerve conduction studies are for evaluation of paraesthesias (insensibility, creeping, fiery) or instability of the arms and legs. The type of study depends on symptoms presented. (Gutmann et al., 2003) NCS studies evaluate the dormancy, magnitude, as well as the pattern of the feedback following stimulation of the peripheral nerve through the skin and tissues by an electrical stimuli. The principle of nerve conduction studies (Mallik, Weir., 2005) In NCS we apply depolarizing electrical pulse square wave to the skin over a peripheral nerve generating a proliferate nerve action potential (NAP) recorded at a distant point over the same nerve. A compound  muscle action potential (CMAP) originating from the awaking of muscle grains in a destination muscle supplied by the nerve. These propagate nerve action potential and compound muscle action potential may be cited with surface or needle electrodes. Minor electrodes are restricted to allow around the full muscle stimulated, giving data for the time taken for the rapid axons to conduct an impulse to the muscle and the size of the feedback. Needle electrodes for NCS give authentic conduction time information, but because they evident from a small area of muscle or nerve it gives poor information and making numerical analysis difficult. Also it is difficult to obtain patient cooperation in an invasive technique. Nerves to be tested can either be stimulated through the skin with surface catalyst or it can be tested via a needle fixed close to the nerve or nerve roots. Choice of the stimulant depends on the desire to bracket above and below the  point of a prospective focal contusion and the anatomical opportunity to the applicable structure. (Mallik Weir et al., 2005). Motor nerve conduction performing motor nerve conduction study the surface electrodes overlying a muscle supplied by nerve to be tested is electrically stimulated and compound muscle action potential (CMAP) is recorded . The recording electrodes are fixed using sticky conducive pads placed in to the  overlying target muscle. The effective electrode is placed over the muscle belly and the reference electrode is situated over an electrically inactive site near by muscle tendon. A grounding electrode is placed between the electrodes maintaining a zero voltage reference point. The CMAP  is a calculated voltage response from an individual muscle fiber action potentials. The shortened inactivity of the CMAP is the time from stimulus  to the onset of action and it is a biphasic response with an initial upward deflection followed by a smaller downward deflection. The CMAP  amplitude is consistent from baseline to negative peak (the neurophysiological convention is that negative volta ge is demonstrated by an upward  deflection) and caculated in millivolts (mV) Figure-7: Compound Muscle Action Potential (CMAP) For recording CMAP, the stimulating current or voltage  is constantly increased until a point where there is no increment in CMAP amplitude. It is only at  supramaximal point that reproducible values for CMAP amplitude and the latency between the stimulus and the onset of the CMAP can be recorded  accurately. (Mishra Kalita, 2006) . The nerve is then excited at a more proximal site. In the normal state stimulating a nerve at  proximal site results in two CMAPs of similar shape and amplitude because the like motor axons innervate the muscle fibres making up the response  However, the latency will be greater for proximal stimulation compared with distal stimulation because of the longer distance between the stimulating  and documenting electrodes. The difference in inactivity represents the time taken for the fastest nerve fibre to conduct between the two stimulation  points as well as other factors involving neuromuscular transmission and muscle activation which is comm on to both stimulation sites. (MallikWeir  Gooch Pullman, 2005; Barboi Barkhaus,2004) . If we want to measures the distance between two sites then the fastest  can be calculated as follows: MNCV (m/s) = Distance between stimulation site 1 and site 2 (mm) [latency site 2 latency site 1  measurement the distance between 2 points of stimulation should be atleast10 cm. which reduces the error due to faulty distance  Stimulation at shorter segments of the nerve, however, is necessary in the evaluation of focal compression neuropathies e.g. CTS. Such short segment  stimulation does not allow the effect of focal slowing to be diluted by the unaffected nerve segment (Mishra Kalita, 2006) Sensory  StudiesThe sensory nerve action potential (SNAP) is achived by electrically stimulating sensory nerve fibres by a supra maximal stimulus and caculating the  nerve action potential at a point . Recording the SNAP orthodromically indicate to distal nerve stimulation and recording more  proximally (the direction in which physiological sensory conduction occurs). Recording the SNAP antidromically refers to proximal nerve stimulation  and recording more distally (opposite in order to the physiological sensory conduction occurs). Different laboratories have different antidromic or  orthodromic methods for testing different nerves. The acceleration correlates directly with the sensory latency, because the residual latency which  comprises neuromuscular transmission time and muscle propagation time is not applicable in sensory nerve conduction and therefore, either the results  may be expressed as latency over a standard distance, or acceleration. Only 20% largest diameter and fastest conducting sensory nerve fibres are  using in the conventional studies functionally supplying fine touch, vibration, and position sense. Predominantly small fibre neuropathies affecting  the 80% of fibres existing with prominent symptoms of pain and conventional studies .The various abnormal findings  are conduction slowing, conduction blockage, lack of responses,or low amplitude responses. NCV studies can acknowledge the degree of demyelination  and axonal loss in the segments of nerve examined. Demyelination of a nerve results in prolongation of conduction time (decreased conduction  velocity), where as axonal loss generally leads to the loss of nerve fiber and muscle potential amplitude. ( Mallik ,Weir., 2005)

One Day in the Life of Ivan Denisovich :: One Day in the Life of Ivan Denisovich Essays

One Day in the Life of Ivan Denisovich: Deeper into the Character When Alexander Solzhenitsyn wrote One Day in the Life of Ivan Denisovich in 1962, he crossed political barriers in his explanation of the Siberian prison camp. Through his character Ivan Denisovich, Solzhenitsyn shows us a normal day in the camp. The book has no chapters, so it is like the reader is spending the day with Ivan. Through this day, he tells of the people, the life conditions, what things are to be done and what things are not to be done. One Day. . . takes us from the wake up call to lights out, with only meals and work between. Nevertheless, because this is only one day, it is hard to really know and understand the characters. Yet, Solzhenitsyn uses flashbacks to show the different sides to his character Ivan Denisovich. Solzhenitsyn uses quite a few major flash backs to show the history of the characters; yet, there were two distinct examples he uses to show Ivans feelings. These two flashbacks help us to understand his humanity and optimism. When he is at his first work camp, he receives many letters and packages from his wife. These letters talk of things happening at home while the packages contain food and tobacco. Yet, every time he receives a package, only a small portion gets to Ivan after all of the appropriate people take their cuts. Therefore, despite his need for food, he writes to his wife and tells her to stop sending the packages. He wants her to save the bread for their children. Even though he asks her to not send any more packages, he still longs for someone to run up to him and say "Shukhov (Ivan) what are you waiting for? You've got a package!" (P.160). No one ever does, nor does he expect them to. As much as he wants the package, he doesn't want his family to suffer on his account. This situation shows the reader the caring and compassionate side of Ivan. It shows the reader of his capacity to give up his own food on behalf of his family. Ivan is a very loving father, yet, without this example, the reader would lose an important aspect of his character. Only through this flashback are we able to see this side of him.

Dylan Marlais Thomas :: essays research papers

  Ã‚  Ã‚  Ã‚  Ã‚  Ã¢â‚¬Å"I’ve had eighteen straight whiskies. I think that’s the record.†(Quoted by John Malcolm Brinnin, Dylan Thomas in America). One of the most renowned authors of the twentieth century, Dylan Thomas is as well known for his philosophical poetry, critical writings, and essays. Often focusing on themes as birth, death, love, and religion, Thomas's works remain distinctly personal through a blend of rich language, detailed imagery, and psychological issues. Thomas is a poet known greatly for his indulgence in his love for poetry and literature. Parallel to this is the unique way Thomas was able to write his works about ideas and themes outside the environment he was contained to live within. His strict childhood and middle age life, which was largely filled with drinking, and wondering slums played some part in shaping his work, but can be overlooked if studied correctly.   Ã‚  Ã‚  Ã‚  Ã‚  Dylan Marlais Thomas was born on October 27, 1914, in the Welsh seaport of Swansea. Both his parents held respectable jobs and he lived under a middleclass household. His mother, in particular lead Dylan from an early age to be a serious reader and writer of poetry. Dylan’s interest in poetry and literature was sparked at an early age, and by high school Dylan was editing for his school newspaper. Aside from editing, Dylan also published his own works which frequently appeared in other publications.   Ã‚  Ã‚  Ã‚  Ã‚  Ã¢â‚¬Å"It is particularly clear from his early poems, where Marc Alyn has observed, all of his originality is already on view, that he was occupied with introspections that lie outside of time and place, and that his style owes comparatively little to tradition and experience.†(Dylan Thomas) Unlike many writers, Dylan was able to explore with ideas that he frequently could not compare his own life with. Dylan’s early poetry was greatly influenced by his friend Daniel Jones. The two friends often wrote plays, and developed poems by drawing lines out of a hat and piecing them together. These were the beginnings of Dylan’s career as a writer and poet.   Ã‚  Ã‚  Ã‚  Ã‚  Before long he was reporting and writing feature articles for the paper and its weekly supplement, The Herald of Wales. Thomas began to spend much of his time exploring the streets, pubs, and alleys of the depression-ridden seaport town in which he lived. Even though, well off himself, Thomas found it much more interesting to study and write about these areas (The Life of Dylan Thomas, Constantine Fitzgibbion). Dylan Marlais Thomas :: essays research papers   Ã‚  Ã‚  Ã‚  Ã‚  Ã¢â‚¬Å"I’ve had eighteen straight whiskies. I think that’s the record.†(Quoted by John Malcolm Brinnin, Dylan Thomas in America). One of the most renowned authors of the twentieth century, Dylan Thomas is as well known for his philosophical poetry, critical writings, and essays. Often focusing on themes as birth, death, love, and religion, Thomas's works remain distinctly personal through a blend of rich language, detailed imagery, and psychological issues. Thomas is a poet known greatly for his indulgence in his love for poetry and literature. Parallel to this is the unique way Thomas was able to write his works about ideas and themes outside the environment he was contained to live within. His strict childhood and middle age life, which was largely filled with drinking, and wondering slums played some part in shaping his work, but can be overlooked if studied correctly.   Ã‚  Ã‚  Ã‚  Ã‚  Dylan Marlais Thomas was born on October 27, 1914, in the Welsh seaport of Swansea. Both his parents held respectable jobs and he lived under a middleclass household. His mother, in particular lead Dylan from an early age to be a serious reader and writer of poetry. Dylan’s interest in poetry and literature was sparked at an early age, and by high school Dylan was editing for his school newspaper. Aside from editing, Dylan also published his own works which frequently appeared in other publications.   Ã‚  Ã‚  Ã‚  Ã‚  Ã¢â‚¬Å"It is particularly clear from his early poems, where Marc Alyn has observed, all of his originality is already on view, that he was occupied with introspections that lie outside of time and place, and that his style owes comparatively little to tradition and experience.†(Dylan Thomas) Unlike many writers, Dylan was able to explore with ideas that he frequently could not compare his own life with. Dylan’s early poetry was greatly influenced by his friend Daniel Jones. The two friends often wrote plays, and developed poems by drawing lines out of a hat and piecing them together. These were the beginnings of Dylan’s career as a writer and poet.   Ã‚  Ã‚  Ã‚  Ã‚  Before long he was reporting and writing feature articles for the paper and its weekly supplement, The Herald of Wales. Thomas began to spend much of his time exploring the streets, pubs, and alleys of the depression-ridden seaport town in which he lived. Even though, well off himself, Thomas found it much more interesting to study and write about these areas (The Life of Dylan Thomas, Constantine Fitzgibbion).

Is Frankenstein a reality? Essay -- Technology Society

Mary Shelley’s 1818 book, Frankenstein, started a popular trend with authors and movie screen writers of science fiction and horror. For over a century now, movies have been produced replicating the Frankenstein novel and the mysteries revolving around creating life from scratch. Numerous films show humans creating creatures or monsters, with good intentions, only for something to go wrong and the creation creates havoc on everyone involved. Viewers will find every variation of creation from cloning to mixing chemicals. In Frankenstein body parts were stitched together like patchwork creating an odd monstrous looking figure. The moral of the movie gives the viewer the impression that we should never play god. Otherwise, we will need to seek out and destroy what we created, just as Victor Frankenstein wanted to do. However, these movies are actually becoming a reality to a certain extent. Is it possible that the Frankenstein myth may actually become a reality in the near futur e? Scientist and doctors have been hard at work for many years to make this fiction a reality. When Frankenstein, was made into a movie in 1931, a memorable scene from it became the dark and gloomy night Victors creation came to life. The violent thunder and lightning had the audience predicting an intense moment was about to occur. Victor’s dead corpse was raised to an opening at the top of the ceiling where a magnificent display of light is shown jolting the machines connected to his creation. After the corpse was completely descended back into the laboratory, Victor notices a slight movement of the corpse’s stitched on hand. He shouts â€Å"Look! It’s moving. It’s alive! It’s alive! Oh in the name of God. Now I know what it feels like to be God.† Soon after,... ...tp://www.huffingtonpost.com/david-ropeik/scientists-bring-back-art_b_583876.html> . Sato, Rebecca. â€Å"Playing God† Scientists in Final Stage of Creating man-made Life.† Daily Galaxy. The Great Discoveries Channel. 21 June 2007. Web. 5 Dec. 2010 . Sato, Rebecca, and Casey Kazan. â€Å"The Ilulissat Manifesto-Creating Artificial Life.† The Daily Galaxy. The Great Discoveries Channel, 12 Mar. 2008. Web. 5 Dec. 2010. . Shelley, Mary, Frankenstein. Romantic Circles. University of Maryland. Stuart Curran. Web. 7 Nov 2010 . Tigges, Sabina. â€Å"Clint Hallam: Guinea Pig Takes the Reins.† Guinea Pig Zero. 29 Dec. 2005. Web. 5 Dec. 2010 .

Apple vs Samsung

Which one is better, Apple or Samsung? Along with the rapid development of science and technology, electronic products has became a very important part of our life. And there are many electronic companies in the world such as Apple, Sony and Samsung. Apple and Samsung are two of the most famous electronic companies in the world. They both produce abundant kinds of electronic products such as smartphones, tablets and computers. So there are many comparisons of these two companies' products. In 2011, there is a lawsuit of Apple accused the Samsung that they damage their many patents in samrtphones and tablets fields (Jackson, 3).Also Apple's complaint included specific federal claims for patent infringement, false designation of origin, unfair competition, and trademark infringement, as well as state-level claims for unfair competition. (Jackson, 4)Although Apple won the lawsuit, however after that the Samsung accused Apple as well. And these lawsuits are still continuous. These make p eople pay more attention of the comparison of the two companies. Many people want to know which one is the best electronic company in the world. To answer this question different people have different ideas.Most people think Apple is better, however others prefer Samsung. And, following are researches about the two companies, they will tell people the reasons that why Apple is better. Apple Inc. is an multinational corporation headquartered in Cupertino, California that designs, develops, and sells consumer electronics, computer software, and personal computers. The company was founded on April 1, 1976, and incorporated on January 3, 1977( –, para. 9). There are many kinds of products that it produce, however Its best-known hardware products are the Mac line of computers, the iPod, the iPhone and the iPad. Also Case Study will describe why Apple Inc. is a very successful company.Its software includes the OS X and iOS operating systems and the iTunes media browser ( Fisher , 3). Apple is the world's third-largest mobile phone maker after Samsung and Nokia. Fortune magazine named Apple the most admired company in the United States in 2008, and in the world from 2008 to 2012 (Fisher, 5). However, the company has received widespread criticism for its contractors' labor practices, and for Apple's own environmental and business practices (Musgrove, 35). All these things tell us that Apple is a successful company and it have a powerful strength. pic] Figure 1 The logo of Apple This logo is the logo of the Apple Inc. The silvery white give a person with science and technology feeling. This is the meaning of the logo: the bite off the gap arouse the curiosity of people, doubt, want to know the taste of apple will personally have a taste (Niv N. P. ). According to Michael M. Scott the former pre sident of Apple Inc. â€Å"it is the most expensive and creative logo ever designed. â€Å"( para, 5) Samsung is a South Korean multinational conglomerate company headquartered in Samsung Town, Seoul.It comprises numerous subsidiaries and affiliated businesses, most of them united under the Samsung brand, and is the largest South Korean company. Samsung produces around a fifth of South Korea's total exports and its revenues are larger than many countries' GDP; in 2006, it would have been the world's 35th-largest economy. The company has a powerful influence on South Korea's economic development, politics, media and culture, and has been a major driving force behind the â€Å"Miracle on the Han River† (kelly, 56). Samsung is also a great company, it is the South Korea's national industry.And it is the pride of all the South Korea people. As well Samsung is a company has a long history, it was made up in 1938, and with the 75 years of development, it has became a world-class company. Samsung also has many famous products, but the most well-known is the Galaxy series products, such as smartphones Galaxy s3 and tablets Galaxy note2. [pic]Figure 2 The logo of Samsung This figure is the logo of Samsung company, it is a concise and clear design, and the sideling background expressed Samsung people's positive and enterprising spirit (Niv N. P. ).All above show people the powerful of the Samsung company, it has the strength to compete with the Apple company. With the fast development of technology, a lot of new stuff appeared. These products become the most powerful things to prove the technology of their company. Many experts do researches to compare these products of two companies because products can tell people the quality of each company clearly. In addition , all the products top class products from smartphones and tablets market. Such as iphone5 and galaxy s3. People compare every details of them and try find which one is better.Through Chaffin's resear ch people can found that a lot of evidences that believe iphone5 is better. Firstly, iphone5 unveiled at 2012 September, at the first week, iPhone 5 sold millions. Even galaxy s3 sold 10 millions units during 4 months, iphone5 just cost 7 days got the half number of galaxy s3 sold for four months( Chaffin, 1). Then, he make some further analysis that start with design. The thick of iphone5 is 7. 6mm and galaxy3 is 8. 6 mm. iPhone 5 just makes the body as thin as possible, a full millimeter less than Samsung galaxy 3. ( Chaffin, 3). And apple has also try to make the phone feel a bit less severe in the hand.Even there also had some slight issue happened on iphone5, because of a part of outer skin made by aluminum ,the character is more easier be scratched. A lot of user feels a little angry about this. Next, for screen, obviously galaxy 3’s is bigger. but the Apple's technology is higher. it makes the screen looks more clear. For power, just like before iPhone always use non-r emovable battery and galaxy use removable battery(Chaffin, 3). According to this research, they think iPhone5 is better than galaxy s3. From this, Apple is better than Samsung in Smartphone field.When it comes to tablet market. According to Catanzariti the tablet expert ,†New pad have the best scream –‘retina'. The ‘retina' screen is by far and away the best display on any mobile device we've come across. (page, 2) . People can see the texts on this screen more clearly and easily. Even Photos and videos look bright and vivid can have a better presentation. The iPad's screen is so sharp that it constantly highlights the low quality of many images on the Internet ( Catanzariti, para3). By comparison, the Samsung Galaxy Note 10. 1 has a larger screen with a rather standard low resolution .Whatever from the definition or the presentation of texts and pictures Samsung Galaxy Note less the than the new iPad. This means it won't be able to display the same super cr isp text as higher resolution screens. ( Catanzariti, para5). So most researchers prefer New iPad, and it can prove that Apple is better than Samsung in tablet field. In computer market, Apple is better , Apple's computers such as Macbook is one of the top class computers in the world, and Samsung do not has any computer reach it. Young people prefer Apple's computers because its fashion appearance design and they give them a sense of science and technology.However, the Samsung's computer do not have these factors, just have a common appearance. Adult people prefer Apple's computers because they have a perfect operating system, and it's very help for design and other professional works. In addition , Apple computers users are more than 3 times of Samsung's users in the USA ( –, para 7). Researchers also do many researches of satisfaction. According to J. D. POWER& ASSOCIATES 2012 U. S. TABLET SATISFACTION STUDY, apple tablets are tops in customer satisfaction. The study measu red satisfaction using five factors on a combined 1,000 point among customer who used their tablet for less than 2 years.The factors include such as performance, ease of operation, styling and design, features, and price. [pic]Figure 3 Tops In User Satisfaction:TWICE: This Week in Consumer Electronics Figure 3 show Apple’s tablet satisfaction is most high, achieving a score of 848 by considering well in performance, ease of operation, styling and design, and features. Amazon followed closely at 841, and Samsung came in third as got 827 rating. And below the industry average of 832 points, followed by Acer, Barnes &Noble, and HP. Gap between Samsung and Apple's score of 21.Although it is a low number ,his is not a number to be ignored, because the users number of their tablets are very high. In comparison with the only Apple and Samsung, as this research, customer prefer Apple’s tablet more than Samsung’s tablet. Some people can say that this study alone, in this paper’s conclusion cannot say Apple is better. However, The survey was based on experiences reported by 1,985 tablet owners in July 2012. (Calif, para 6) Overall satisfaction was 857 among owners who watch three or more hours of video per week on their tablet, or 45 points more than people who don’t. Calif, para7) In addition, people who spend three or more hours seeing video are more likely to purchase another tablet from their current manufacturer in the future than are those who do not watch as much video content, the company said. The percentages are 90 percent and 81 percent, respectively. The survey also found that tablet owners spend 7. 5 hours per week browsing the Internet, watching videos, listening to music and reading books on their device compared with 9. 6 hours per week on a personal computer for the same activities. As can see, tablet was used various functions and multiple perform by applications that use the master. Calif, para 8) When seen from a va riety of used tablet, Can expect that the Apple tablet preference and other Apple’s products are also better than Samsung’s one. As mentioned earlier in this paper, as well as that Apple can be seen to people to more go ahead and advanced technology, productivity than Samsung’s did. With the researches above, more people prefer Apple. However according to the Beer Jeff the author of [APPLE SMASHER â€Å"In the second quarter of 2012, Samsung shipped about 50 million smartphones, the most ever sipped in a single quarter by any vendor, according to market research firms Strategic Analytics and IDC Worldwide.By contrast, in the latest quarter Apple sold 26 million iPhones and Research In Motion shipped just 7. 4 million Blackberries†. (Para 7) He also discusses about the consumer goods company Samsung, and also pay attention on the Samsung’s business strategies about how Samsung can selling more smartphones than the company Apple. Besides this article include what different between Samsung and Apple’s social media marketing, hardware and software. However, he just talk about the sales of only one year and only in the smartphone field.When it comes to the whole electronic products market share, Apple takes more parts than Samsung. The user of Apple of electronic products is also more than the users of Samsung. In addition, after the Samsung lost the lawsuit, many Samsung users sold their phones, they wonder some functions of Samsung phones would not work. Samsung indispensable to Apple is a good competitor, Of these two companies compete, consumers are able to access the more advanced technology. These positive competition exist Samsung and Apple, and the company has made efforts to better technology and customer service.Therefore, competition continues to be positive, and the evolving technology in consumer products to better fit their own would pick that. (Carrier, 6) The two companies all have their advantages and short comings, they are better than each other in different fields, but with the comparison they have, the both becoming better. In conclusion, this paper shows the various aspects, the current technology in society the more advanced the opinion that Apple's products have. Works Cited Catanzariti, Ross. â€Å"Tablet comparison: Apple new iPad vs.Samsung Galaxy Note 10. 1. † Web. 10 August. 2012. Chaffin,Bryan. Spec Comparison: Apple’s iPhone 5 vs. Samsung Galaxy S3: The Mac Observer. 15 Sep, 2012. Print. Calif, Apple, Amazon Tablets . Tops In User Satisfaction:TWICE: This Week in Consumer Electronics, 1 October. 2012. Beer, Jeff. â€Å"Apple smasher†. 10/29/2012, Vol. 85 Issue 17, p54-57, 4p, 5 Color Photographs. Mlot, Stephanie. † Galaxy S III Helps Samsung Widen Smartphone Lead Over Apple. † Jul 2012, p1-1, 1p. — , â€Å"Apple Investor Relations â€Å"FAQ, Apple inc.Retrieved March 2, 2007. Kelly ,Olsen . â€Å"Samsung chairman resigns over sca ndal†. Associated Press via Google News. Archived fromthe original. Retrieved June 4, 22. Jackson,White International Business Times. â€Å"Apple vs. Samsung-The Legal Battle†. 05 Oct. 2012 Fisher, Anne â€Å"America's Most Admired Companies†. Fortune 157 (5): 65–67. March 17, 2008 Carrier, Michael A. â€Å"A Roadmap to the Smartphone Patent Wars and FRAND Licensing† (PDF). CPI Antitrust Chronicle (Social Science Electronic Publishing) . Retrieved July 27, 2012.

Etiology and Pathogenesis of Alzheimer’s disease

Alzheimer’s disease is a degenerative brain disorder and is the main cause of dementia. The major clinical manifestations of Alzheimer’s disease include gradual loss of memory and language. Other major symptoms and signs of this disease are psychiatric and behavioral abnormalities and disabilities in the routine or daily living activities.The etiology and Pathogenesis of Alzheimer’s disease include various factors. Biological Factors Even though the etiology and pathogenesis of Alzheimer’s disease is still not known fully, it is discovered to involve a complex mix of genetic as well as environmental factors.Among genetic and environmental factors, genetic factor is proved to be playing a major role in the etiology and pathogenesis of Alzheimer’s disease. The most important cause of Alzheimer’s disease is found to be the mutations in chromosomes 21, 14 and 1 which are spread or moved in a typical autosomal dominant mode. These mutations make p rotein overproduction in neuritic plaques, B amyloid. Even though the beginning of the familial form is often early, the nature and route of the disorder is found to be influenced by few environmental factors.But it is found out that familial form is responsible for only a negligible proportion of cases of Alzheimer’s disease (even less than five percent) (Cummings et al. , 1998b). Nearly fifty percent of the people who are having ancestors with Alzheimer’s disease are found to be getting this disorder once they enter their 80s and 90s (Mohs et al. , 1987). Few genotypes (the model of genetic inheritance in a person’s body) are found to give risk for the late-onset Alzheimer’s disease (which is very common).Taking an example, the ApoE-e4 allele on chromosome 19, that encourages the deposition of B amyloid, is proved to increase the risk for developing Alzheimer’s disease (Corder et al. , 1993). All other genes that are doubted to be responsible for the development of Alzheimer’s disorder are being studied (Kang et al. , 1997). Apart from this particular reason, there are various other biological risk factors that contribute to the development of Alzheimer’s disorder Cummings et al. , 1998b).Cognitive capabilities and aging are among the biological factors. The manner in which these traits contribute to the increased risk is not still proved, however, it is proved in the medical field that the numerous neurobiologic changes that are associated with the normal aging of the brain of a person also contribute to the major risk factors of Alzheimer’s disorder. As people get into the later part of their life, this age related neurobiologic changes make then more liable for Alzheimer’s disorder.These neurobiologic changes include neuron and synaptic loss, lessened dendritic span, reduced size and density of neurons present in the nucleus basalis of Meynert, and poor cortical acetylcholine levels (Cummings et al. , 1998b). Based on these factors and the frequency and occurrence curve of this disorder, medical researchers have come to the conclusion that people are very much liable to Alzheimer’s disorder if their life span is extended (beyond the normal age) beyond eighties and nineties (up to 100 and 150). People above 90 years are highly susceptible to Alzheimer’s disorder.Among this, those who have Alzheimer’s history in their family are 90 % prone to this disorder. Protective Factors Apart from the biological factors there are various other factors that influence the onset of Alzheimer’s disease. Various protective factors that are powerful enough to delay the commencement of Alzheimer’s disorder have been discovered. For example, Genetic endowment with the ApoE-e2 allele is capable of reducing the risk of Alzheimer’s disorder (Duara et al. , 1996). The exact role and the original mechanism of action of ApoE-e2 allele, however, are not com pletely understood.Deep thinking, higher educational level and wisdom are also proved to be associated with the delay in the commencement of Alzheimer’s disease (Stern et al. , 1994; Callahan et al. , 1996a). Few medication and drugs are also found to be good for delaying the onset of Alzheimer’s disorder. For example, medications, like nonsteroidal anti-inflammatory drugs (Andersen et al. , 1995; McGeer et al. , 1996) and estrogen replacement therapy (Paganini-Hill & Henderson, 1994), are found to be effectively delaying the commencement of Alzheimer’s disease.Apart from this, Vitamin E and the drug selegiline (otherwise known as deprenyl) are also proved to holdup the crucial stages of the course of Alzheimer’s disorder, for example the nursing home placement, serious functional impairments or disorders as the disease progresses and lead to death (Sano et al. , 1997). According to Behl et al. , 1995, the course of action of the protective agents in a pe rson is not completely known; however, these agents are proved to check the toxic action of oxidative stress (through antioxidants like vitamin E or estrogen).These agents also counter the work of inflammatory mediators related to plaque formation (through anti-inflammatories) (Mark et al. , 1995). Histopathology The pathophysiology of Alzheimer’s disorder is also proved to be associated with the histopathologic variations in Alzheimer’s disease. These histopathologic changes include neuritic plaques, synaptic loss, neurofibrillary tangles, hippocampal granulovacuolar degeneration, and B amyloid angiopathy (Cummings et al. , 1998b).Majority of the genetic and epigenetic risk factors are some or the other way linked with B amyloid. This has helped the medical researchers to conclude that the formation of B amyloid peptide is the most crucial pathological event or step in the course of spread of Alzheimer’s disorder in a person (Cummings et al. , 1998b; Hardy & Hi ggins, 1992). A successful intervention in the course of Alzheimer’s disease spreading may include get in the way of any of the numerous steps included in the slow progress of Alzheimer’s disease pathogenetic cascade.Few of the intervention modes include intervening to reduce B amyloid generation from the amyloid precursor protein, intervening to decrease the B amyloid aggregation as well as the generation of beta-pleated sheets, and intervening in the amyloid-related neurotoxicity process. Successful interference in these steps may help interrupt Alzheimer’s spread. Apart from this, few therapies can successfully block the neuronal cell death and can slow down the inflammatory response occurring in neurotic plaques.Therapies are also proved to inhibit the work of certain growth factors and hormones and also delay the replenishment of deficient neurotransmitters. As the complete obstruction of the processes within the B amyloid cascade may affect the usual cereb ral metabolic processes, successful interruptions may bring about partial interruptions (Cummings & Jeste, 1999). Studies about the molecular neuroscience of Alzheimer’s disease have researched several crucial aspects of pathophysiology and etiology.Researchers are working to thoroughly understand the entire processes and reasons behind cell death, neuronal degeneration and subsequent memory degradation. Medical world is expecting new revelations from these studies and are on the way to lay a new therapeutic path for eliminating Alzheimer’s disease from the world (National Institute on Aging, 1996). Medical world is expecting researchers to come out with the real physiological factor that makes a human body prone to Alzheimer’s syndrome. Role of AcetylcholineAcetylcholine is also suspected to play a part in encouraging Alzheimer’s disorder in a person. Loss or decrease of the neurotransmitter acetylcholine also is proved to be responsible for the pathogen esis of Alzheimer’s disease. Postmortem researches in Alzheimer’s disease infected people have explained the loss or reduction of basal forebrain and cortical cholinergic neurons and the exhaustion of choline acetyltransferase, which is the enzyme that carry out acetylcholine synthesis (Mesulam, 1996). Several post mortem reports have come out with the same reason.The scale of this central cholinergic deficit is associated with the severity of dementia that results in the ‘cholinergic’ hypotheses of cognitive deficits in Alzheimer’s disorder (Mesulam, 1996). This hypothesis and the clinical researches have proved that Acetylcholine play a major role in Alzheimer’s disease. However, acetylcholine is not the only neurotransmitter that encourages the growth of Alzheimer’s disorder in a patient. Researchers are still working to find out the role of other substances in the pathogenesis of the Alzheimer’s disorder.The researches relat ed to the pharmacological treatment of this syndrome are coming out with new results. It has been proved that a delay or break in the spread of Alzheimer’s disease is proved to reduce its prevalence in the body of a patient even by half (Breitner, 1991). In order to inhibit the spread of this syndrome in a person it is necessary to delay the onset of the disease to such an extent where mortality from other resources surpasses the frequency of the steps of the disease.So the most crucial step in inhibiting Alzheimer’s disease is the identification of the factors that stop the onset or slow down the progress of the disease in the patient. Working on these agents would help reduce the spread of the disease. References Aarts, P. , & Op den Velde W. (1996). Prior traumatization and the process of aging. In B. A. van der Kolk, A. C. McFarlane, & L. Weisath (Eds. ), Traumatic stress: The effects of overwhelming experience on mind, body and society (pp. 359–377). New Yo rk: Guilford Press. Abrams, R. C. , Rosendahl, E. , Card, C. , & Alexopoulos, G. S. (1994).Personality disorder correlates of late and early onset depression. Journal of the American Geriatrics Society, 42, 727–731. Adams, W. L. , Garry, P. J. , Rhyne, R. , Hunt, W. C. , & Goodwin, J. S. (1990). Alcohol intake in the healthy elderly. Changes with age in a cross-sectional and longitudinal study. Journal of the American Geriatrics Society, 38, 211–216. Aevarsson, O. , & Skoog, I. (1996). A population-based study on the incidence of dementia disorders between 85 and 88 years of age. Journal of the American Geriatrics Society, 44, 1455–1460. Aiken, L. (1990). Chronic mental illness. In B. S. Fogel, A. Furino, & G.Gottlieb (Eds. ), Mental health policy for older Americans: Protecting minds at risk. Washington, DC: American Psychiatric Press. Albert, M. S. , Jones, K. , Savage, C. R. , Berkman, L. , Seeman, T. , Blazer, D. , & Rowe, J. W. (1995). Predictors of cogniti ve change in older persons: MacArthur studies of successful aging. Psychology and Aging, 10, 578–589. Alexopoulos, G. S. (1997, November 6). Epidemiology, nosology and treatment of geriatric depression. Paper presented at Exploring Opportunities to Advance Mental Health Care for an Aging Population, meeting sponsored by the John A. Hartford Foundation, Rockville, MD.