Neurons, the building blocks of the brain, are an astonishingly capable type of cell. Collectively they can store, manipulate and retrieve biologically important information, allowing animals to learn and adapt to environmental changes. This universal adaptability is widely believed to be due to plasticity: the readiness of neurons to manipulate and adjust their intrinsic properties and strengths of connections to other cells. It is through such modifications that associations between neurons can be made, giving rise to memory representations; for example, linking a neuron responding to the smell of pancakes with neurons encoding sweet taste and general gustatory pleasure. However, this malleability inherent to neuronal cells poses a dilemma from the point of view of stability: how is the brain able to maintain stable operation while in the state of constant flux? First of all, won’t there occur purely technical problems akin to short-circuiting or runaway activity? And second of all, if the neurons are so easily plastic and changeable, how can they provide a reliable description of the environment? Of course, evidence abounds to testify to the robustness of brains, both from everyday experience and scientific experiments. How does this robustness come about? Firstly, many control feedback mechanisms are in place to ensure that neurons do not enter wild regimes of behaviour. These mechanisms are collectively known as homeostatic plasticity, since they ensure functional homeostasis through plastic changes. One well-known example is synaptic scaling, a type of plasticity ensuring that a single neuron does not get overexcited by its inputs: whenever learning occurs and connections between cells get strengthened, subsequently all the neurons’ inputs get downscaled to maintain a stable level of net incoming signals. And secondly, as hinted by other researchers and directly explored in this work, networks of neurons exhibit a property present in many complex systems called sloppiness. That is, they produce very similar behaviour under a wide range of parameters. This principle appears to operate on many scales and is highly useful (perhaps even unavoidable), as it permits for variation between individuals and for robustness to mutations and developmental perturbations: since there are many combinations of parameters resulting in similar operational behaviour, a disturbance of a single, or even several, parameters does not need to lead to dysfunction. It is also that same property that permits networks of neurons to flexibly reorganize and learn without becoming unstable. As an illustrative example, consider encountering maple syrup for the first time and associating it with pancakes; thanks to sloppiness, this new link can be added without causing the network to fire excessively. As has been found in previous experimental studies, consistent multi-neuron activity patterns arise across organisms, despite the interindividual differences in firing profiles of single cells and precise values of connection strengths. Such activity patterns, as has been furthermore shown, can be maintained despite pharmacological perturbation, as neurons compensate for the perturbed parameters by adjusting others; however, not all pharmacological perturbations can be thus amended. In the present work, it is for the first time directly demonstrated that groups of neurons are by rule sloppy; their collective parameter space is mapped to reveal which are the sensitive and insensitive parameter combinations; and it is shown that the majority of spontaneous fluctuations over time primarily affect the insensitive parameters. In order to demonstrate the above, hippocampal neurons of the rat were grown in culture over multi-electrode arrays and recorded from for several days. Subsequently, statistical models were fit to the activity patterns of groups of neurons to obtain a mathematically tractable description of their collective behaviour at each time point. These models provide robust fits to the data and allow for a principled sensitivity analysis with the use of information-theoretic tools. This analysis has revealed that groups of neurons tend to be governed by a few leader units. Furthermore, it appears that it was the stability of these key neurons and their connections that ensured the stability of collective firing patterns across time. The remaining units, in turn, were free to undergo plastic changes without risking destabilizing the collective behaviour. Together with what has been observed by other researchers, the findings of the present work suggest that the impressively adaptable yet robust functioning of the brain is made possible by the interplay of feedback control of few crucial properties of neurons and the general sloppy design of networks. It has, in fact, been hypothesised that any complex system subject to evolution is bound to rely on such design: in order to cope with natural selection under changing environmental circumstances, it would be difficult for a system to rely on tightly controlled parameters. It might be, therefore, that all life is just, by nature, sloppy.

MACEDO, D. X. Informação de Fisher e entropia de Shannon de osciladores com massa dependente da posição. 2017. 65 f. Tese (Doutorado em Física) – Centro de Ciências, Universidade Federal do Ceará, Fortaleza, 2017. / Submitted by Giordana Silva (giordana.nascimento@gmail.com) on 2017-04-12T20:33:31Z No. of bitstreams: 1 2017_tese_dxmacedo.pdf: 1506351 bytes, checksum: 0451b11cb3bbdfca718fe5d35f2c8a80 (MD5) / Approved for entry into archive by Giordana Silva (giordana.nascimento@gmail.com) on 2017-04-12T20:34:02Z (GMT) No. of bitstreams: 1 2017_tese_dxmacedo.pdf: 1506351 bytes, checksum: 0451b11cb3bbdfca718fe5d35f2c8a80 (MD5) / Made available in DSpace on 2017-04-12T20:34:02Z (GMT). No. of bitstreams: 1 2017_tese_dxmacedo.pdf: 1506351 bytes, checksum: 0451b11cb3bbdfca718fe5d35f2c8a80 (MD5) Previous issue date: 2017 / In this work we study from both classical and quantum point of view the position dependent mass harmonic oscillator (PDMHO). Classically, we use the Legendre transformation to find the Hamiltonian of the system. Next, we define two functions, and , to simplify the hamiltonian of the PDMHO. By using the Poisson algebra we find the expressions for the position and moment. At last, by using a canonical transformation we relate the equations of the PDMHO to those of the simple harmonic oscillator (SHO). Quantically, we write the Hamiltonian of the PDMHO in terms of the operators and . Next, we consider that these operators satisfy the same algebra that those of the SHO. By assuming that both the classical and quantum PDMHO have the same form, we are able to find a simple form for the PDMHO Hamiltonian. Finally, by transforming the Schrödinger equation (SE) of the PDMHO into that of the SHO, we can write the wave function of the PDMHO in terms of that of the SHO. We will study two time-dependent systems, namely and , we observe that as , they tend to a simple harmonic oscillator. For each system we find the position and momentum (classical study), as well as the wave-function (quantum study). For both systems we analyze the the position e momentum uncertainty, the product uncertainty, the fisher information and Shannon entropy, for the ground state, as a function of the parameter. / Neste trabalho estudamos clássica e quanticamente o oscilador harmônico com massa dependente da posição (OHMDP). Na parte clássica, utilizamos a transformação de Legendre para encontrar a hamiltoniana do sistema. A seguir definimos duas funções e para escrevermos a hamiltoniana do OHMDP de uma forma mais simples. Utilizando a álgebra de Poisson encontramos as expressões para a posição e o momento. Por fim, através de uma transformação canônica veremos como relacionar as equações do OHMDP com aquelas do oscilador harmônico simples (OHS). Na parte quântica, escrevemos a hamiltoniana do OHMDP em termos de operadores e . Em seguida, vamos supor que estes operadores satisfaçam a mesma relação de comutação que os operadores abaixamento e levantamento do OHS. Analisando que condição deve ser satisfeita para que os osciladores OHMDP clássico e quântico tenham o mesmo potencial, encontramos uma forma simplificada da hamiltoniana do OHMDP. Em seguida, transformamos a equação de Schrödinger (ES) para o OHMDP na ES para o OHS. Assim, obtemos a função de onda do OHMDP em termos da função de onda do OHS. Estudaremos dois sistemas com massa dependente da posição, a saber: e , vemos que quando , recaímos no OHS. Para cada sistema encontraremos a posição e o momento (estudo clássico), bem como a função de onda (estudo quântico). Para os dois sistemas analisaremos também o comportamento da incerteza na posição, incerteza no momento, produto de incerteza, informação de Fisher e entropia de Shannon, para o estado fundamental, em função do parâmetro de deformação.

SILVA, G. F. Oscilador harmônico de Caldirola-Kanai e aplicação da Teoria da Informação de Fisher e Entropia de Shannon. 2017. 61 f. Dissertação (Mestrado em Física) – Centro de Ciências, Universidade Federal do Ceará, Fortaleza, 2017. / Submitted by Pós-Graduação em Física (posgrad@fisica.ufc.br) on 2017-06-13T15:46:22Z No. of bitstreams: 1 2017_ dis_gfsilva.pdf: 1262336 bytes, checksum: 0e6010a0850b0ac2aed199269f2335be (MD5) / Approved for entry into archive by Giordana Silva (giordana.nascimento@gmail.com) on 2017-06-13T21:30:10Z (GMT) No. of bitstreams: 1 2017_ dis_gfsilva.pdf: 1262336 bytes, checksum: 0e6010a0850b0ac2aed199269f2335be (MD5) / Made available in DSpace on 2017-06-13T21:30:10Z (GMT). No. of bitstreams: 1 2017_ dis_gfsilva.pdf: 1262336 bytes, checksum: 0e6010a0850b0ac2aed199269f2335be (MD5) Previous issue date: 2017 / CAPES / In this dissertation, we give a brief historical overview of the elements that form it, namely Quantum Harmonic Oscillators with explicit temporal dependence; Lewis & Riesenfelds Method of the Invariants associated with Hartley & Rays technique; Shannon’s entropy and Fisher’s information theory. In this introductory description, we seek to present a procedural view of scientific knowledge. Also, in the introduction, we present the motivations for the execution of the academic work and its organization. In a later chapter, we describe Lewis and Riesenfeld’s formalism applied to oscillators that have an explicit temporal dependency. To better describe it, we divide the chapter into sections in which we define the Invariant, find its self-states, relate the self-states with the Schrödinger’s solution, and apply the formalism to the time-dependent oscillator which, in our work, was the well-known Caldirola-Kanai with M(t) = m eγt. We find the solutions in the coordinate of the position and, after that, we work with the wave function of the ground state. In the following chapter, we determine the uncertainty. To do so, we use the creation and destruction algebra of operators, So known by physicists. We find the Shannon’s entropy and Fisher’s information. We do an analysis of the analytical and graphical results, establishing a comparison between these techniques. / Nesta dissertação, fazemos um breve histórico dos elementos que a compõem, a saber, Osciladores Harmônicos Quânticos com dependência temporal explícita; Método dos Invariantes de Lewis e Riesenfeld associado com a técnica de Hartley e Ray; Entropia de Shannon e Teoria da informação de Fisher. Na descrição introdutória, buscamos apresentar uma visão processual dos conhecimentos científicos. Ainda, na introdução, apresentamos as motivações para a execução do trabalho acadêmico e sua organização. Em capítulo posterior, descrevemos o formalismo de Lewis e Riesenfeld aplicados a osciladores que têm uma dependência temporal explícita. Para melhor descrever, dividimos o capítulo em seções nas quais definimos o Invariante, encontramos seus autoestados, relacionamos os autoestados com a solução de Schrödinger e aplicamos o formalismo ao oscilador com dependência temporal que, para o nosso trabalho, foi o conhecido Oscilador de Caldirola-Kanai com M(t) = m eᵞt. Encontramos as soluções na coordenada da posição e, após, trabalhamos com a função de onda do estado fundamental. No capítulo seguinte, determinamos a incerteza. Para tanto, utilizamos a álgebra de operadores criação e destruição, tão conhecida pelos físicos. Encontramos a entropia de Shannon e a Informação de Fisher. Por fim, uma análise dos resultados analíticos e gráficos, estabelecendo uma comparação entre as técnicas.

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Master of Science / Department of Statistics / Haiyan Wang / Cancer type classification with high throughput molecular data has received much attention. Many methods have been published in this area. One of them is called PAM (nearest centroid shrunken algorithm), which is simple and efficient. It can give very good prediction accuracy. A problem with PAM is that this method selects too many genes, some of which may have no influence on cancer type. A reason for this phenomenon is that PAM assumes that all genes have identical distribution and give a common threshold parameter for genes selection. This may not hold in reality since expressions from different genes could have very different distributions due to complicated biological process. We propose a new method aimed to improve the ability of PAM to select informative genes. Keeping informative genes while reducing false positive variables can lead to more accurate classification result and help to pinpoint target genes for further studies. To achieve this goal, we introduce variable specific test based on Edgeworth expansion to select informative genes. We apply this test on each gene and select some genes based on the result of the test so that a large number of genes will be excluded. Afterward, soft thresholding with cross-validation can be further applied to decide a common threshold value. Simulation and real application show that our method can reduce the irrelevant information and select the informative genes more precisely. The simulation results give us more insight about where the newly proposed procedure could improve the accuracy, especially when the data set is skewed or unbalanced. The method can be applied to broad molecular data, including, for example, lipidomic data from mass spectrum, copy number data from genomics, eQLT analysis with GWAS data, etc. We expect the proposed method will help life scientists to accelerate discoveries with highthroughput data.

Made available in DSpace on 2014-06-12T18:31:12Z (GMT). No. of bitstreams: 2 arquivo7578_1.pdf: 735911 bytes, checksum: f459b01de36c59e7809bb426437d278f (MD5) license.txt: 1748 bytes, checksum: 8a4605be74aa9ea9d79846c1fba20a33 (MD5) Previous issue date: 2011 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Nesta dissertação é apresentada uma solução estacionária para um modelo de dinâmica populacional de uma única espécie, considerando a dispersão da população num espaço heterogêneo e um crescimento logístico da população. No primeiro capítulo, para dar ao leitor alguma intimidade com os conceitos apresentados estudamos alguns modelos de dinâmica populacional de uma única espécie. Referimo-nos a uma única população para dizer que não analisamos aqui a interação entre diversas espécies. No segundo capítulo concentra-se a parte substancial do nosso trabalho. Na seção 1 apresentamos o modelo, na seção 2 apresentamos a solução estacionária para o problema e na seção 3 fazemos uma discussão sobre efeitos de isolamento para uma população.

Psychobiographical researchers methodically formulate life histories and interpret them by means of psychological theories. The research typically focuses on exemplary and completed lives. The cases that are studied are usually of individuals who are of particular interest to society as a result of excelling in their particular fields, be they to society’s benefit or detriment. Antwone Fisher was chosen for this study using purposive sampling as he meets the psychobiographical requirement of being an extraordinary individual. Fisher grew up in the Foster Care System and faced many abusive experiences as child. Despite difficult beginnings, Fisher developed into a stable and creative adult who excels as a poet, screenwriter and film director. The primary aim of this study is to describe and interpret the life of Antwone Fisher through Erikson’s theory of psychosocial development. The data was processed and analysed using Miles and Hubermans’ general view of qualitative analyses as well as Alexander’s method of asking the data questions. This study contributes to the development of psychobiographical research in South Africa as well as to personality and developmental theory.

The compositions of Fisher Aubrey Tull are widely performed and many have become standard repertoire. Tull's compositions encompass a multiplicity of performance media including works for orchestra, chorus, symphonic band, jazz band, brass choir, and solo and chamber works. Tull's compositional output for the trumpet is prolific and is acknowledged to be music of high quality. An examination of Trumpet and Brass Programs, compiled and published annually by the International Trumpet Guild, shows Tull's solo and ensemble works for trumpet to be frequently performed. Furthermore, his compositions for trumpet have been performed and recorded by internationally acclaimed artists including Vincent DiMartino, Terry Everson, Håkan Hardenberger, Anthony Plog, Carl "Doc" Severinsen and Allen Vizzutti.This study investigates Fisher Tull's eight solo works for trumpet, which include: Vignette for Trumpet and Piano (1954); Concerto No. 1 for Trumpet and Orchestra (1964); Concerto No. 2 for Trumpet and Band (1974); Three Bagatelles for Trumpet and Piano (1975); Eight Profiles for Solo Trumpet (1978); Rhapsody for Trumpet and Band (1980); Sonata for Trumpet and Piano (1986); and Chromutations for Solo Trumpet (1988). Histories of each composition are chronicled. An analysis of formal organization and significant style features examines musical structure, harmonic language, rhythmic character, instrumentation, and orchestration. A discussion of technical concerns specific to the trumpet that addresses range, tessitura, articulation, flexibility, endurance and the use of extended techniques is included. Performance suggestions, pertaining to technical and artistic issues, offer the reader specific recommendations as an aid in performance preparation. Finally, the significance of Fisher Tull's works for trumpet and his impact on the trumpet literature is assessed. Evidence suggests that his prolific compositional output, diversity of forms, and musical quality rank him as one of the most significant composers for the trumpet in the twentieth century.

“Valparaiso, Round The Horn”, a collection of short stories, contends with the following vital concerns: How are we transported? Why do we believe each other? What is our tendency towards legend? How do we immortalize one another? What is ritual to the avowed non-believer? How can we feel such heartbreak about someone who died before we were born? Will we ever understand each other? Is there grace in misunderstanding? Is there genius in it? A long time ago, could people run as fast as horses? What is the use in anything less than myth?

Social and computer networks permeate our lives. Large networks, such as the Internet, the World Wide Web (WWW), AND wireless smartphones, have indisputable economic and social importance. These networks have non-trivial topological features, i.e., features that do not occur in simple networks such as lattices or random networks. Estimating characteristics of these networks from incomplete (sampled) data is a challenging task. This thesis provides two frameworks within which common measurement tasks are analyzed and new, principled, measurement methods are designed. The first framework focuses on sampling directly observable network characteristics. This framework is applied to design a novel multidimensional random walk to efficiently sample loosely connected networks. The second framework focuses on the design of measurement methods to estimate indirectly observable network characteristics. This framework is applied to design two new, principled, estimators of flow size distributions over Internet routers using (1) randomly sampled IP packets and (2) a data stream algorithm.