Density Functional Theory (DFT): Literature Review

Density Functional Theory (DFT): Literature Review Theoretical Background and Literature Review 2.1 Density Functional Theory This section covers basics about Density Functional Theory (DFT), which is the theoretical method behind our investigations. For those who are interested in a much more deep knowledge about the DFT we refer to textbooks such as [29] and [30]. 2.1.1 History of Density Functional Theory To get precise and accurate results from both theoretical and computational methods, the scale of physical phenomena must be well defined. In physics and material science the relevant scales of matter are time and size. In computational material science, for the multiscale understanding in both time and size scale the smallest relevant scale of atomic interactions are best described by ab initio techniques. These techniques are based on the determination of electronic structure of the considered materials and an intelligent transfer of its characteristics to higher-order scales using multidisciplinary schemes. More specifically, if the interaction of electrons is solely described using universal principles such as the fundamental laws of quantum mechanics condensed in the Schrodinger equation, these simulations are called firstprinciples, or ab initio methods. One can also separate those methods as Hartree-Fock and post-HF techniques that mainly uses by quantum chemistry field and De nsity Functional Theory (DFT) which is typically used in of material science. Ab initio simulations are becoming remarkably popular in scientific research fields. For example in DFT case, in a simple search at Web Of Science [31] or any other publication search tool, one can easily see that number of publications that include †Density Functional Theory† in their title or abstract is over 15000 in 2013. Therefore, it can be concluded that, ab initio based research already an important third discipline that makes the connection between experimental approaches and theoretical knowledge. Figure 2.1: Usage trend of DFT over years Within ab initio simulations quantum mechanical equations for any system that may be ordered or disordered are solved. That actually gives one drawback which is, solving that kind of equations is generally only possible for simple systems, because of the expensive electron-electron interaction term. So, in general, the ab initio simulations are restricted to 150-200 atoms calculations with most powerful computer clusters. Due to the that severe limitation, better techniques and methods are developed and implemented to bring the real materials into realm of ab initio simulations. The major development of ab initio methods with practical applications took place when many electron interactions in a system was possible to be approximated using a set of one electron equations (Hartree-Fock method) or using density functional theory In 1927, Thomas [32] and Fermi [33] introduce a statistical model to compute the energy of atoms by approximate the distribution of electrons in an atom. Their concept was quite similar to modern DFT but less rigorous because of the crucial manybody electronic interaction was not taken into account. The idea of the Thomas and Fermi was that, at the starting point for simplicity that electrons do not interact with each other and using classic terms, therefore, one can describe the kinetic energy as a functional of electron density of non-interacting electrons in a homogeneous electron gas. 3 years later, in 1930, Dirac [34] succeeded to include the many-body exchange and correlation terms of the electrons and actually he formulated the local density approximation (LDA), that is still used in our days. However, the Thomas-Fermi and Dirac model that are based on homogeneous electron gas do not cover the accuracy demand in current applications. In same the years as Thomas and Fermi, Hartree [35] also introduce a procedure to calculate approximate wavefunctions and energies for atoms and that was called Hartree function. Some years later, to deal with antisymmetry of the electron system, his students Fock [36] and Slater[37], separately published self-consistent functions taking into account Pauli exclusion principals and they expressed the multi-electron wavefunction in the form of single-particle orbitals namely Slater-determinants. Since the calculations within the Hartree-Fock model are complicated it was not popular until 1950s. The fundamental concepts of density functional theory were proposed by Hohenberg and Kohn in their very well known paper in the year 1964 [38]. The main idea was trying to use the electron density instead of complex and complicated wavefunction. A wavefunction contains 3N variables, where N is the number of electrons and each electron has 3 spatial degrees of freedom. In contrast to that electron density contains only 3 variables. Therefore, the implementation of the electron density with 3 variables will be more easy to handle than 3N wavefunction variables. In their work, Hohenberg and Kohn proved that all ground state properties of a quantum system, in particular the ground state total energy, are unique functionals of the ground state density. However, the Hohenberg-Kohn (HK) formulation is not useful for actual calculations of ground state properties with enough accuracy. A major improvement was achieved one year later, in 1965. Kohn and Sham [39] proposed a formulation by partially going back to a wavefunction description in terms of orbitals of independent quasi particles. The main idea was that the many-body problem can be mapped onto a system of non-interacting quasiparticles. This approach simplified the multi-electron problem into a problem of non-interacting electrons in an effective potential. This potential includes the external potential and the effects of the Coulomb interactions between the electrons, e.g., the exchange and correlation interactions. Since then up to now the Kohn-Sham equations are used in practically all calculations based on DFT. 2.1.2 Schr ¨odinger’s Equation In quantum mechanics, analogue to Newtons equations in classical mechanics, the Schr ¨odinger equation is used. This is a partial differential equation and used to describe the physical quantities at the quantum level. The Schr ¨odinger equation forms the basis of many ab initio approaches and its non-relativistic form is an eigenvalue equation of the form: HˆÎ ¨(ri,Rj)= EÃŽ ¨(ri,Rj) (2.1) where ÃŽ ¨(ri,Rj) is the wavefunction of the system depending on the electron coordinates ri,i =1N and the coordinates of all nuclei in the system Rj,j =1M. Hˆis the Hamiltonian of a system that contains M nuclei and N electrons. Therefore, the Schr ¨odinger equation that involves both nuclei and electrons has to be solved for the many-body eigenfunctions ÃŽ ¨(r1,r2, , rN ; R1,R2, , RM ). The many-body Hamiltonian can be written in the form: Hˆ= Tˆe + Tˆn + Vˆnn + Vˆen + Vˆee (2.2) ˆˆ where all of parts are operators. Te and Tn are the kinetic energies of the ˆˆ electrons and nuclei, respectively. Ven, Vee and Vˆnn represent the attractive electrostatic interaction between the electron and the nuclei and the repulsive potential due to the electron-electron and nucleus-nucleus interactions. One can also write them down explicitly: N f2 ˆ Te = − 2 i (2.3) 2me i=1 M 2Mn n=1 f2 ˆ Tn = − 2 n (2.4) 11 M ZnZme2 = (2.5) 4Ï€ 0 2 |Rn − Rm| =1;n,mn =m ˆ Vnn ˆ Ven = − 11 MN Zne2 (2.6) 4Ï€ 0 2 |ri − Rn| n=1 i=1 j= M e = (2.7) 4Ï€ 0 2 |ri − rj| i,j=1;i 2 11 ˆ Vee where me and Mn are the electron and nuclei masses, Zn is the nuclear number of the n-th atom, e is the electronic charge and f is the Planck constant. For simplicity one can also use atomic units. Then the Hamiltonian takes the form: NMM ZnZm in 22 |Rn − Rm| i=1 n=1 n,m=1;n =m 1 1 ˆ H = − 2 2 − + (2.8) j= MNMZn − + |ri − Rn||ri − rj| n=1 i=1 i,j=1;i 2.1.3 Born-Oppenheimer Approximation It is clear that forces on both electrons or nuclei is in the same order of magnitude because of their electric charge. Therefore, the expected momen 1 tum changes due to that forces must be the same. However electrons are much smaller than nuclei (e.g. even for Hydorgen case nuclei nearly 1500 times larger than an electron) they must have higher velocity than nuclei. One can conclude that electrons will very rapidly adjust themselves to reach the ground state configuration if the nuclei start moving. Born and Oppenheimer [40] published their work in 1927, they simply separated the nuclear motion from electronic motion which is now known as the Born-Oppenheimer approximation. Therefore, while solving the Hamiltonian Equation in (2.8) one can simply assume nuclei as stationary and solve the electronic ground state at first then calculate the energy of the system in that configuration and solve the nuclei motion. Then the separation of electronic and nuclear motion leads to an separation of the wavefunctions ÃŽ ¨ = ψφ of electrons and nuclei, respectively. Via the separation one can treat the nuclear motion externally by not in cluding the Hamiltonian and the â€Å"electronic† Hamiltonian can be written as: Hˆe = Tˆe + Vˆen + Vˆee (2.9) Solving the equation (2.9), one can get the total energy of the ground state of the system, which can be defined as: E0 = ψ0|He|ψ0 + Vnn (2.10) where E0 is the ground state total energy of the system and ψ0 is the eigenfunction of the electronic ground state. 2.1.4 Hohenberg-Kohn Theorem However, the Hamiltonian in Equation (2.9) is quite complicated to solve for realistic systems due to the high number of electrons and especially the term Vee makes it impossible to solve the problem exactly. Therefore, instead of solving the many-body wavefunctions, Hohenberg-Kohn deal with that problem by reducing it to the electron density Ï (r). This approach makes the fundamentals of DFT. According to Hohenberg and Kohn, the total energy of the system can be defined via the electron density as E = E[Ï (r)] and it will be the minimum for the ground state electron distribution, namely Ï 0(r). Therefore, the exact theory of many-body systems reduced to the electron density that can be defined as: Ï (r)= d3 r2d3 rN |ψ(r1, rN )|2 (2.11) and has to obey the relation: Ï (r)d3 r = N (2.12) where N is the total number of electrons in the system. One can also summarize the HK theorem in the form of the two main theorems, Theorem I : The external potential vext(r), which is the potential energy generated by the nuclei, can be determine from the ground state electron density Ï 0(r). Then Hamiltonian will be fully defined, also the wavefunction for the ground state will also be known. Theorem II : E0,the ground state total energy of the system with a particular vext will be the global minimum when Ï  = Ï 0. From the perspective of these two theorems one can write down the total electronic energy as: E[Ï ]= Te[Ï (r)] + Ï (r)vext[Ï (r)] + EH [Ï (r)] + Exc[Ï (r)]d3 r (2.13) One can also add the kinetic energy of the electrons T − e[Ï (r)], the classical Coulomb interaction (or Hartree interaction) between electrons EH [Ï (r)] and the remaining complex non-classical electron exchange correlations Exc[Ï (r)] into an universal functional FHK [Ï (r)]: E[Ï ]= FHK [Ï ]+ Ï (r)vext[Ï (r)]d3 r (2.14) The remaining will be to apply the variational principle to extract the ground state energy ÃŽ ´E[Ï (r)] |Ï =Ï 0 = 0 (2.15) ÃŽ ´Ã (r) 2.2 Kohn-Sham Equations However, the Equation (2.14) does not give an accurate solution. In that point, Kohn and Sham reformulated the current approach and introduced a new scheme by considering the orbitals by mapping the fully interacting electronic system onto a fictitious system of non-interacting quasi particles moving in an effective potential.The Kohn-Sham equations solution can be written as: ˆ HKSψi = iψi (2.16) where the Hamiltonian is HˆKS =[− 1 2 + Veff (r)] (2.17) 2 Therefore, the problem of finding the many-body Schr ¨odinger equation is now replaced by solving single particle equations. Since the KS Hamiltonian is a functional of just one electron at the point r then the electron density can be defined according to HK theorem: occ. Ï (r)= |ψi(r)|2 (2.18) i=1 Besides, kinetic energy term and the classical Coulomb interaction energy of the electrons can be define as: N 1 d3 Te = − r|ψi(r)|2 (2.19) 2 i=1 1 Ï (r)Ï (r ) EH [Ï ]= d3rd3 r(2.20) 2 |r − r | Then the Hohenberg-Kohn ground state energy cn be written according to Kohn-Sham approach: N ÃŽ ´Exc EKS = i − EH [Ï ]+ Exc − (2.21) ÃŽ ´Ã (r) i i are the one electron energies and are coming from the results of KS equations results, however it has low physical meaning. The most significant term in the Equation (2.20) is the last term. which is the exchange correlation term that contains all the many-body interactions of exchange and interactions of the electrons. One can also write down it as in the form of Hohenberg-Kohn universal functional from the equation: Exc[Ï ]= FHK [Ï ] − (Te[Ï ]+ EH [Ï ]) (2.22) The total ground state energy can be obtained from EKS in Equation (2.21). Since it contains only the electronic energy, the total ground state energy of the system is calculated by adding the nuclei-nuclei repulsion term: E0(R1, , RM )= i − EH [Ï 0]+ Exc[Ï 0] − vxcÏ 0dr + Vnn(R1, , RM ) (2.23) where E0 is the total ground state energy for a given atomic configuration (R1, , R2). Therefore, the total energy depend on ionic positions that is actually depends on the volume and cell shape, so one can easily compute the ground state structure by minimizing the total energy. Also one can find the force acting on the particular atom, say atom A, by taking the derivative of the energy with respect to ionic position of A: ÃŽ ´E0(R1, .., RM ) FA(RA) = (2.24) ÃŽ ´RA which also shows the total energy dependence on atomic positions. 2.3 Calculating the Exchange-Correlation Energy The derived and brieà ¯Ã‚ ¬Ã¢â‚¬Å¡y explained KS equations from the fundamentals of all modern DFT calculations today. The most important point in the solution of KS equations are the exchange-correlation functional Exc which also determines the quality of the calculation. There are two well known approximation methods to get the exchange correlations: local density approximation (LDA)[39] and generalized gradient approximation (GGA)[41, 42]. 2.3.1 Local Density Approximation The local density approximation starts with a very simple approximation that, for regions of material where the charge density is slowly varying, the exchange-correlation energy at that point can be considered as the same as for a local uniform electron gas of the same charge density. In that case one can write the Exc as: Exc = Ï (r) xc(r) (2.25) where xc(r) is the exchange correlation energy per electron in an homogenous electron gas of density Ï (r). Even though the approximation is seemingly simple it is suprisingly accurate. However, it also has some drawbacks such as under-predict on of ground state energies and ionisation, while overpredicting binding energies as well as slightly favouring the high spin state structures and does not work fine for some systems where the charge density is rapidly changing. 2.3.2 Generalized Gradient Approximation Knowing the drawbacks of LDA the most logical step to go beyond LDA is not to limit oneself to the information about the charge densitiy Ï (r) at a particular point r, but also adding the information about the gradient of the charge density Ï (r) to be able to take into account the unhomogeneous density in the system. Then one can write the exchange correlation energy as : Exc[Ï ]= f(Ï , Ï )dr (2.26) That way of description leads to an improvement over LDA, nevertheless in some systems LDA still works better. There also several different parameterizations of GGA while in LDA its only one. In GGA some of these parameterizations are semi-emprical, in that experimental data (e.g. atomization energies) is used in their derivation. Others are found entirely from first principles. A commonly used functional is the PW91 functional, due to Perdew and Yang [43, 44] and most commonly used today is PBE [45, 46] by Perdew, Burke and Ernzerhof. 2.4 Ultra-Soft Pseudopotentials and the Projector-Augmented Wave Method In the previous section, the calculation of Exc is described. Nevertheless this is not the single sensitive point of DFT calculations. The other point is the treatment of the electron-nuclei interaction. There are several available methods that describes the electron-nuclei interaction, but the most effective

Ten Guiding Principles for Organizations Essay -- Business Management

Ten Guiding Principles Introduction Every organization’s success depends on the organization’s ethical behavior and accountability for its actions. Nonprofit organizations are no different. On the contrary these organizations have a greater difficult in succeeding. Each aspect of a nonprofit organization requires the time, energy, strength, passion and fortitude of simple individuals who have the vision and mission of the organization at hand. This essay will explain and use Florence Green’s ten guiding principles as indicated by Ronald Riggio and Sarah Orr, share a Guam nonprofit organization and how it measures up to the ten guiding principles. Green’s Ten Recommended Guiding Principles As indicated by Riggio & Orr (2004), the following are the ten recommended guiding principles that non-profit organizations must do in the twenty-first century: (a) become a learning organization; (b) become a transformational leader; (c) form strategic alliances; (d) give accountability and ethical behavior top priority; (e) develop indicators that measure the consequences on the community; (f) adopt results-based budgeting tied to indicators; (g) financially empower the organization so that it can do more mission over time; (h) creatively rethink resource development governance, and management styles; (i) adopt a vision and a mission that incorporate diversity; (j) be at the table (as explained by Green, 2004, p. 19-35). Leaders must commit to utilizing the guiding principles their non-profit organizations can further promote and provide the awareness and service that they sent out to accomplish. Principle One: Become a learning organization. With the first guiding principle nonprofit organization want to continue to expand its ide... ...nd its stakeholders. With the open awareness of HIV/AIDS, there is more legislation that is being introduced and more public or private testimonies must be heard. Conclusion In conclusion, the Guahan Project analysis which was directed by Florence Green’s ten guiding principles indicated that this non-profit organization is on the right track and so long as it keeps to its vision, mission and objective to include diversification whenever necessary, it will succeed. Non-profit organizations like Guahan Project, promotes opportunities for all to volunteer or contribute to a worthwhile cause. Works Cited Aidsportal (2010). Guahan project, Guam HIV/AIDS Network. Retrieved from http://www.aidsportal.org/Organisation_Details.aspx?orgid=1455 Riggio, R. & Orr, S. (2004). Improving leadership in non-profit organizations. San Francisco, California: Jossey-Bass.

Barangay health center informayion system Essay

The Barangay Health Care Management Information System is a community-based and patient-directed organization. Its goal is to provide first aid, maternal and child health care, diagnosis of social diseases, and other basic health services to all the members of the community it is serving. Primary Health Care is one of the top priorities of the city government. This is proven by the existence of barangay health center. It is usually the first point of contact between residents of the community and other health care facility levels. Health Care gives high importance to education, nutrition, preventive medicine and treatment of the most common diseases and injuries. It is considered as a practical means of giving any form of health care for every people that live in Barangay. Barangay Health Center services are regulated by the (DOH). Projects may be spearheaded by each Center under the supervision of the local government and the municipal health officer. Every health Center is equipped to provide primary level of health care. Barangay Health Center is commonly staffed of doctors, public health nurses, nutritionists, medical technicians, rural health midwives, Barangay health workers dentists, etc. The goal of Health Center is beneficial for all. It aims to reduce health exclusion and social disparities. It helps in organizing health services according to people’s needs and expectations. It also works on integrating health into all sectors. Barangay Health Workers live in the communities they serve, and act as change agents in their communities. They provide information, education and motivation services for primary health care, maternal and child health, child rights, family planning and nutrition. They may administer immunizations and regular wei ghing of children. They often assist midwives in providing birthing services. Health Center management information systems are information management system that capture and display data related to the delivery of health care services. And health Center  management information system is not just a system of computers and software. It includes clinical guidelines, medical terminology dictionaries, and interfaces the various diagnostic devices and other clinical and business information databases, such as laboratory, pharmacy and diagnostic imaging. It is also used for public health and medical research purpose.

Islamic Political Economy in National Development

GMGF5324 POLITICAL ECONOMY ASSIGNMENT: ISLAMIC POLITICAL ECONOMY IN NATIONAL DEVELOPMENT PREPARED FOR: DR. KAMARUDDIN ABDULSOMAD PREPARED BY: FATIN HANANI BINTI TARMIDZI 1. WHAT KIND OF NATIONAL DEVELOPMENT HE WAS MENTION? 2. WHAT APPROACH HE DISCUSS IN HIS TALK? 3. YOU COMMENTS? â€Å"The Economic Philosophy of National Development† is the title of what has been presented by Lt. Kol. Prof. Dr. Abdul Razak Chin. He had explained a lot of brilliant ideas on political, national development, mercantilism, Islamic thought and also Islamic political economic in order to develop the nation.First of all, what is economic philosophy that very important in order to achieving the national development? What is philosophy that he had explained in his talk and what kind of philosophy that had be the main key nowadays? According to Lt. Kol. Prof. Dr. Abdul Razak Chin, philosophy in general is philosophy is that branch of knowledge which relates to the concept of divinity. Besides that, with philosophy that we had use, we will endeavor to find the truth and achieve success. Al-Farabi (339H-950M) had explained that philosophy in the context of the love of wisdom or wisdom, and also become cord to every branch of science.In addition, al-Farabi also refers wisdom as makrifullah – a way to know God. Based on my understanding, philosophy is a reflexive question in the threefold sense: it is about philosophy, it is raised by philosophers themselves and, last but not least, it represents an old and difficult philosophical problem. This multiple reflexivity is the reason why trying to find out what philosophy is inevitably becomes not only a way of dealing with philosophy but actually the way of doing philosophy. Once we start discussing philosophy we cannot scape its intellectual grip. Then, he also mentions in his talk that the human needs are no limitation. Human will gain and earn everything that they want as long as they can achieve their mission, target and etc. S econdly, he had explained about national development that had been a main point in his talk. National development refers to the process of national development and to lead a sustainable level of repairs and improvement. National development is also very concerned about the economic development refers to the index per capita.If the index of per capita income at constant rate surpassed the national population growth rate, which means place of steady economic growth and the result is the development of the country. In his talk, he has focus on Islamic political economy in national development. He has explained about the dimension of Islamic development. In order to achieve national development in term of Islam, we need to focus on the three main points. There are dharuriyyat (essential goods), hajiyyat (comfortable), and kamaliat/tahsiniyyat (luxury needs). These three main points should base on syarie or Islamic law.Based on my understanding, we need to balance and equals developing t he nation based on Islamic law and also consider the citizen needs and interest. As a leader and elites itself, the welfare of the citizen very important includes the economis, social life, health care, education etc. Without the citizen especially middle class and workers who are the agents of society and ruling the institution or country, it may affect the country and the economic. It means without them especially the citizens itself; government cannot move and implement their policy.It also may affect the national development. Therefore, I can see how relate the concept of Islamic with national development. Without the relation or combination of national development in Islamic concept, there are many problems that country to solve. According to Lt. Kol. Prof. Dr. Abdul Razak Chin, specifically, an understanding of the economy is appropriate emphasis to the issue of how people use resources and factors of production to achieve well-being (welfare) life (falah) in this world and th e hereafter.Thus, there are seven core areas of the economy to complement the welfare of individuals, communities and nations. * Economic activity based on good intentions and purposes. * Reasonableness obligatory on Kifayah. * Business world without compromising herafter. * Avoid illegal transactions (haram) and syubhah. Last but not least, mercantilism is economic nationalism for the purpose of building a wealthy and powerful state. Adam Smith coined the term â€Å"mercantile system† to describe the system of political economy that sought to enrich the country by restraining imports and encouraging exports.The goal of these policies was, supposedly, to achieve a â€Å"favorable† balance of trade that would bring gold and silver into the country and also to maintain domestic employment. In contrast to the agricultural system of the physiocrats or the laissez-faire of the nineteenth and early twentieth centuries, the mercantile system served the interests of merchants and producers such as the British East India Company, whose activities were protected or encouraged by the state.The basic proposition of Mercantilism is that the state should aim to maximize it's wealth through one-way trade with other countries, maximizing exports and keeping imports to a minimum. The developing countries are in debt due to letalknding policies with interest that they can't pay back, the developed countries export goods into these countries whilst making it very hard for the developing countries to export their own goods in return. The richer are getting richer and the poorer are getting poorer. This is what is happening now.This is mercantilism. My Comments In my opinion, Lt. Kol. Prof. Dr. Abdul Razak Chin has explain details about the Islamic perceptions on national development. He has explain base on Islamic concept that includes world and hereafter (akhirah). He also has described the Islamic concept and theory based on a few Islamic thinkers thought. For ins tance, the sustainability in the country should follow the Islamic concepts. Citizens have their own rights and freedom, and they also the people that increase the national economic and development.Hopefully, I can join this Inaugural Professional Talk again next time. A very brilliant and knowledgeable talk by a educated level like Prof. and Dr presented during that time and all the postgraduate candidates need to attend to gain knowledge and experience. Thank you to Dr Kamaruddin because give me a chance to attend that talk last week. Hopefully, I will grab the opportunity and keep it as my great moment attend the talk with very special conditions and environment. Being around lecturer makes me to be a lecturer or civil servants in future!

Basal Ganglia Function and Location

Basal Ganglia Function and Location The basal ganglia are a group of neurons (also called nuclei) located deep within the cerebral hemispheres of the brain. The basal ganglia consist of the corpus striatum (a major group of basal ganglia nuclei) and related nuclei. The basal ganglia are involved primarily in processing movement-related information. They also process information related to emotions, motivations, and cognitive functions. Basal ganglia dysfunction is associated with a number of disorders that influence movement including Parkinsons disease, Huntington disease, and uncontrolled or slow movement (dystonia). Basal Nuclei Function The basal ganglia and related nuclei are characterized as one of three types of nuclei. Input nuclei receive signals from various sources in the brain. Output nuclei send signals from the basal ganglia to the thalamus. Intrinsic nuclei relay nerve signals and information between the input nuclei and output nuclei. The basal ganglia receive  information from the cerebral cortex and thalamus through input nuclei. After the information has been processed, it is passed along to intrinsic nuclei and sent to output nuclei. From the output nuclei, the information is sent to the thalamus. The thalamus passes the information on to the cerebral cortex. Basal Ganglia Function: Corpus Striatum The corpus striatum is the largest group of basal ganglia nuclei. It consists of the caudate nucleus, putamen, nucleus accumbens, and the globus pallidus. The caudate nucleus, putamen, and nucleus accumbens are input nuclei, while the globus pallidus is considered output nuclei. The corpus striatum uses and stores the neurotransmitter dopamine and is involved in the reward circuit of the brain. Caudate Nucleus: These  C-shaped paired nuclei (one in each hemisphere) are located primarily in the frontal lobe region of the brain. The caudate has a head region that curves and extends forming an elongated body that continues to  taper at its tail. The tail of the caudate ends in the temporal lobe at a limbic system structure known as the amygdala. The caudate nucleus is involved in motor processing and planning. It is also involved in memory storage (unconscious and long-term), associative and procedural learning, inhibitory control, decision making, and planning.Putamen: These  large rounded nuclei (one in each hemisphere) are located in the forebrain and along with the caudate nucleus  form the dorsal striatum. The putamen is connected to the caudate nucleus at the  head region of the caudate. The putamen is involved in voluntary and involuntary motor control.Nucleus Accumbens: These  paired nuclei (one in each hemisphere) are located between the caudate nucleus an d putamen. Along with the olfactory tubercle (sensory processing center in the olfactory cortex), the nucleus accumbens forms the ventral region of the striatum. The nucleus accumbens is involved in the brains  reward circuit and behavior mediation. Globus Pallidus: These paired nuclei (one in each hemisphere) are located near the caudate nucleus and putamen. The globus pallidus is divided into internal and external segments and acts as one of the major output nuclei of the basal ganglia. It sends information from basal ganglia nuclei to the thalamus. The internal segments of the pallidus send the majority of output to the thalamus via the neurotransmitter gamma-aminobutyric acid (GABA). GABA has an inhibitory effect on motor function. The external segments of the pallidus are intrinsic nuclei, relaying information between other basal ganglia nuclei and internal segments of the pallidus. The globus pallidus is involved in the regulation of voluntary movement. Basal Ganglia Function: Related Nuclei Subthalamic Nucleus: These small paired nuclei are a component of the diencephalon, located just below the thalamus. Subthalamic nuclei receive excitatory inputs from the cerebral cortex and have excitatory connections to the globus pallidus and substantia nigra. Subthalamic nuclei have both input and output connections to the caudate nucleus, putamen, and substantia nigra. The subthalamic nucleus plays a major role in voluntary and involuntary movement. It is also involved in associative learning and limbic functions. Subthalamic nuclei have connections with the limbic system through connections with the cingulate gyrus and nucleus accumbens.Substantia Nigra: This large mass of nuclei is located in the midbrain and is also a component of the brainstem. The substantia nigra is composed of the pars compacta and the pars reticulata. The pars reticulata segment forms one of the major inhibitory outputs of the basal ganglia and assists in the regulation of eye movements. The pars compact a segment is composed of intrinsic nuclei that relay information between input and output sources. It is involved mainly in motor control and coordination. Pars compacta cells contain pigmented nerve cells that produce dopamine. These neurons of the substantia nigra have connections with the dorsal striatum (caudate nucleus and putamen) supplying the striatum with dopamine. The substantia nigra serves numerous functions including controlling voluntary movement, regulating mood, learning, and activity related to the brains reward circuit. Basal Ganglia Disorders Dysfunction of basal ganglia structures results in several movement disorders. Examples of these disorders include Parkinsons disease, Huntington disease, dystonia (involuntary muscle contractions), Tourette syndrome, and multiple system atrophy (neurodegenerative disorder). Basal ganglia disorders are commonly the result of damage to the deep brain structures of the basal ganglia. This damage may be caused by factors such as head injury, drug overdose, carbon monoxide poisoning, tumors, heavy metal poisoning, stroke, or liver disease. Individuals with basal ganglia dysfunction may exhibit difficulty in walking with uncontrolled or slow movement. They may also exhibit tremors, problems controlling speech, muscle spasms, and increased muscle tone. Treatment is specific to the causation of the disorder. Deep brain stimulation, electrical stimulation of targeted brain areas, has been used in the treatment of Parkinsons disease, dystonia, and Tourette syndrome. Sources Lanciego, Josà © L., et al. â€Å"Functional Neuroanatomy of the Basal Ganglia.† Cold Spring Harbor Perspectives in Medicine, Cold Spring Harbor Laboratory Press, Dec. 2012.Parr-Brownlie, Louise C., and John N.J. Reynolds. â€Å"Basal Ganglia.† Encyclopà ¦dia Britannica, Encyclopà ¦dia Britannica, Inc., 19 June 2016.Wichmann, Thomas, and Mahlon R. DeLong. â€Å"Deep-Brain Stimulation for Basal Ganglia Disorders.† Basal Ganglia, U.S. National Library of Medicine, 1 July 2011.

J essays

J essays John Quincy Adams was the only son of a president to become president. He had an impressive political background that began at the age of fourteen. He was an intelligent and industrious individual. He was a man of strong character and high principles. By all account, his presidency should have been a huge success, yet it wasn't. John Quincy Adams' presidency was frustrating and judged a failure because of the scandal, attached to his election, the pettiness of his political rivals, and his strong character. John Quincy Adams was born on July 1767, in Braintree Massachusetts. His parents were John and Abigail Adams. "Quincy, had every advantage as a youngster. At the time of his birth, his father was an increasingly admired and prospering lawyer, and his mother Abigail Smith Adams, was the daughter of an esteemed minister, whose wife's family combined two prestigious and influential lines, the Nortons and the Quincys. Accompanying his father on diplomatic missions in Europe, young Joh n Quincy Adams received a splendid education at private schools in Paris, Leiden, and Amsterdam, early developing his penchant for omnivorous reading." He was able to speak several languages. At the age of fourteen, he was asked to serve as secretary and translator to Francis Dana, the first US ambassador to Russia. "Despite his age, young Adams was a valuable aid to the consul; he enjoyed Russia and the exposure to diplomatic circles." He later returned to the United States and attended Harvard. "He graduated in two years and entered the law offices of Theophilus Parsons in Newburyport, Massachusetts. Passing the bar in 1790, he set up practice in Boston." In 1794 John began his long political career. George Washington appointed John Quincy Adams an Ambassador to the Netherlands. After his father was elected as the second president of the United States, he was reassigned to the post of minister to Prussia. He kept this post throughout his fathers t...

CBRN Weapons Essay Example | Topics and Well Written Essays - 500 words

CBRN Weapons - Essay Example Moreover its usage leads to destruction of biological and physical aspects of the environment and may even cause destruction of natural reserves. Your Excellency we also have an option to develop Overly Top Attack Tank Misiles; they are the most current military weapons and can destroy a large number of enemies within a very short time. It can facilitate the take of stagnant and moving targets and has less impact of the environment. They are also not very expensive to develop. However, they can release loud explosive sounds and gases that are harmful to the environment. Our country can also invest in development of modern croddy missiles that provide proper delivery in regard to mass destruction when attacking enemies. These weapons are less expensive as compared to arsenals and OTA’s. However, they also destroy the environment through production of excessive latent heat and explosions. Lastly, we can also explore Chemicals, Biological, Radiological and Nuclear options of military attacks. This can include the use of biological pathogens such as disease causing pathogens during war or the use of Nuclear weapons to attack enemies. These methods are lethal and are usually associated with massive environmental destruction. Your Honour, taking these options into consideration, it is crucial that our country focus on the development of Overly Top Attack Tanks that are basically less expensive to develop and have less effects on the environment as compared to other options. Overly Top Attack tanks can deliver excellent results owing to the fact that they are usually used to attack specific targets. This makes them less destructive to the environment. The essence of their relatively lower cost of development is also important especially to an average economy like