Photoelectron angular distributions from above threshold ionization of hydrogen atoms in strong laser fields

We apply a scattering theory of nonperturbative quantum electrodynamics to study the photoelectron angular distributions (PADs) of a hydrogen atom irradiated by linearly polarized laser light. The calculated PADs show main lobes and jetlike structure. Previous experimental studies reveal that in a set of above-threshold-ionization peaks when the absorbed-photon number increases by one, the jet number also increases by one. Our study confirms this experimental observation. Our calculations further predict that in some cases three more jets may appear with just one-more-photon absorption. With consideration of laser-frequency change, one less jet may also appear with one-more-photon absorption. The jetlike structure of PADs is due to the maxima of generalized phased Bessel functions, not an indication of the quantum number of photoelectron angular momentum states.

Monostable-Bistable Transition Logic Element (MOBILE) Model for Single-Electron Transistors

The traditional monostable-bistable transition logic element (MOBILE) structure is usually composed of resonant tunneling diodes (RTD). This letter describes a new type MOBILE structure consisting of single-electron transistors (i.e. SET-MOBILE). The analytical model of single-electron transistors ( SET) has been considered three states (including an excited state) of the discrete quantum energy levels. The simulation results show negative differential conductance (NDC) characteristics in I-DS-V-DS curve. The SET-MOBILE utilizing NDC characteristics can successfully realize the basic logic functions as the RTD-MOBILE.

Sulfonated polyimides bearing benzimidazole groups for proton exchange membranes

A series of sulfonated polymides containing benzimidazole groups were synthesized using 4,4'-binaphthyl-1,1',8,8'-tetracarboxylic dianhydride (BTDA), 4,4'-diaminodiphenyl ether-2,2'-disulfonic acid (ODADS) as the sulfonated diamine, and 2-(3',5-diaminophenyl)benzimidazole (a) or 6,4'-diamino-2-phenylbenzimidazole (b) as the nonsulfortated diamine. The electrolyte properties of the synthesized polyimides Ia-x, Ib-x, x refers to molar percentage of the sulfonated diamine) were investigated and compared with those of polyimides (Ic-x) from BTDA, ODADS, and m-phenylenediamine (c). All synthesized polyimides possessed high molecular weights revealed by their high viscosity, and formation of tough and flexible membranes. Polyintides with benzimidazole groups exhibited much better swelling capacity than those without benzimiclazole groups. This was attributed to the strong interchain interaction through basic benzimidazole functions and sulfonic acid groups. The sulfortated polyimides that are incorporated with 1, 1',8,8'-binaphthalimide exhibited better hydrolytic stability than that with 1,4,5,8-naphthalimide. Polyimide membranes with good water stability as well as high proton conductivity were developed. Polyimide membrane (Ia - 90), for example, did not lose mechanical properties after being soaked in boiling water for tOOO h, while its proton conductivity was still at a high level (compared to that of Nafion 117).

Localization of the electric-field distribution in graded core-shell metamaterials

The local electric-field distribution has been investigated in a core-shell cylindrical metamaterial structure under the illumination of a uniform incident optical field. The structure consists of a homogeneous dielectric core, a shell of graded metal-dielectric metamaterial, embedded in a uniform matrix. In the quasistatic limit, the permittivity of the metamaterial is given by the graded Drude model. The local electric potentials and hence the electric fields have been derived exactly and analytically in terms of hypergeometric functions. Our results showed that the peak of the electric field inside the cylindrical shell can be confined in a desired position by varying the frequency of the optical field and the parameters of the graded profiles. Thus, by fabricating graded metamaterials, it is possible to control electric-field distribution spatially. We offer an intuitive explanation for the gradation-controlled electric-field distribution.

Dielectric response of graded composites having general power-law-graded cylindrical inclusions

The dielectric response of graded composites having general power-law-graded cylindrical inclusions under a uniform applied electric field is investigated. The dielectric profile of the cylindrical inclusions is modeled by the equation epsilon(i)(r)=c(b+r)(k) (where r is the radius of the cylindrical inclusions and c, b and k are parameters). Analytical solutions for the local electrical potentials are derived in terms of hypergeometric functions and the effective dielectric response of the graded composites is predicted in the dilute limit. Moreover, for a simple power-law dielectric profile epsilon(i)(r) = cr(k) and a linear dielectric profile epsilon(i)(r) = c(b + r), analytical expressions of the electrical potentials and the effective dielectric response are derived exactly from our results by taking the limits b -> 0 and k -> 1, respectively. For a higher concentration of inclusions, the effective dielectric response is estimated by an effective-medium approximation. In addition, we have discussed the effective response of graded cylindrical composites with a more complex dielectric profile of inclusion, epsilon(i)(r)=c(b+r)(k)e(beta r). (c) 2005 American Institute of Physics.

A Theory of Networks for Appxoimation and Learning

Learning an input-output mapping from a set of examples, of the type that many neural networks have been constructed to perform, can be regarded as synthesizing an approximation of a multi-dimensional function, that is solving the problem of hypersurface reconstruction. From this point of view, this form of learning is closely related to classical approximation techniques, such as generalized splines and regularization theory. This paper considers the problems of an exact representation and, in more detail, of the approximation of linear and nolinear mappings in terms of simpler functions of fewer variables. Kolmogorov's theorem concerning the representation of functions of several variables in terms of functions of one variable turns out to be almost irrelevant in the context of networks for learning. We develop a theoretical framework for approximation based on regularization techniques that leads to a class of three-layer networks that we call Generalized Radial Basis Functions (GRBF), since they are mathematically related to the well-known Radial Basis Functions, mainly used for strict interpolation tasks. GRBF networks are not only equivalent to generalized splines, but are also closely related to pattern recognition methods such as Parzen windows and potential functions and to several neural network algorithms, such as Kanerva's associative memory, backpropagation and Kohonen's topology preserving map. They also have an interesting interpretation in terms of prototypes that are synthesized and optimally combined during the learning stage. The paper introduces several extensions and applications of the technique and discusses intriguing analogies with neurobiological data.

A Connection Between GRBF and MLP

Both multilayer perceptrons (MLP) and Generalized Radial Basis Functions (GRBF) have good approximation properties, theoretically and experimentally. Are they related? The main point of this paper is to show that for normalized inputs, multilayer perceptron networks are radial function networks (albeit with a non-standard radial function). This provides an interpretation of the weights w as centers t of the radial function network, and therefore as equivalent to templates. This insight may be useful for practical applications, including better initialization procedures for MLP. In the remainder of the paper, we discuss the relation between the radial functions that correspond to the sigmoid for normalized inputs and well-behaved radial basis functions, such as the Gaussian. In particular, we observe that the radial function associated with the sigmoid is an activation function that is good approximation to Gaussian basis functions for a range of values of the bias parameter. The implication is that a MLP network can always simulate a Gaussian GRBF network (with the same number of units but less parameters); the converse is true only for certain values of the bias parameter. Numerical experiments indicate that this constraint is not always satisfied in practice by MLP networks trained with backpropagation. Multiscale GRBF networks, on the other hand, can approximate MLP networks with a similar number of parameters.

Protein kinase C regulation of cell spreading in the molluscan Biomphalaria glabrata embryonic (Bge) cell line

Judith E. Humphries, Leah Elizondo and Timothy P. Yoshino (2001). Protein kinase C regulation of cell spreading in the molluscan Biomphalaria glabrata embryonic (Bge) cell line. Biochimica et Biophysica Acta - Molecular Cell Research, 1540(3), 243-252. Sponsorship: National Institutes of Health AI 15503 RAE2008

Strategies of actin reorganisation in plant cells

Spatial-temporal flexibility of the actin filament network (F-actin) is essential for all basic cellular functions and is governed by a stochastic dynamic model. In this model, actin filaments that randomly polymerise from a pool of free actin are bundled with other filaments and severed by ADF/cofilin. The fate of the severed fragments is not known. It has been proposed that the fragments are disassembled and the monomeric actin recycled for the polymerisation of new filaments. Here, we have generated tobacco cell lines and Arabidopsis plants expressing the actin marker Lifeact to address the mechanisms of F-actin reorganisation in vivo. We found that F-actin is more dynamic in isotropically expanding cells and that the density of the network changes with a periodicity of 70 seconds. The depolymerisation rate, but not the polymerisation rate, of F-actin increases when microtubules are destabilised. New filaments can be assembled from shorter free cytoplasmic fragments, from the products of F-actin severing and by polymerisation from the ends of extant filaments. Thus, remodelling of F-actin might not require bulk depolymerisation of the entire network, but could occur via severing and end-joining of existing polymers.

Variants in the 1q21 risk region are associated with a visual endophenotype of autism and schizophrenia

Deficits in sensitivity to visual stimuli of low spatial frequency and high temporal frequency (so-called frequency-doubled gratings) have been demonstrated both in schizophrenia and in autism spectrum disorder (ASD). Such basic perceptual functions are ideal candidates for molecular genetic study, because the underlying neural mechanisms are well characterized; but they have sometimes been overlooked in favor of cognitive and neurophysiological endophenotypes, for which neural substrates are often unknown. Here, we report a genome-wide association study of a basic visual endophenotype associated with psychological disorder. Sensitivity to frequency-doubled gratings was measured in 1060 healthy young adults, and analyzed for association with genotype using linear regression at 642758 single nucleotide polymorphism (SNP) markers. A significant association (P=7.9×10) was found with the SNP marker rs1797052, situated in the 5′-untranslated region of PDZK1; each additional copy of the minor allele was associated with an increase in sensitivity equivalent to more than half a standard deviation. A permutation procedure, which accounts for multiple testing, showed that the association was significant at the α=0.005 level. The region on chromosome 1q21.1 surrounding PDZK1 is an established susceptibility locus both for schizophrenia and for ASD, mirroring the common association of the visual endophenotype with the two disorders. PDZK1 interacts with N-methyl-d-aspartate receptors and neuroligins, which have been implicated in the etiologies of schizophrenia and ASD. These findings suggest that perceptual abnormalities observed in two different disorders may be linked by common genetic elements. © 2013 John Wiley & Sons Ltd and International Behavioural and Neural Genetics Society.

On the application of optimal control techniques in lossy fieldbuses

The performance of real-time networks is under continuous improvement as a result of several trends in the digital world. However, these tendencies not only cause improvements, but also exacerbates a series of unideal aspects of real-time networks such as communication latency, jitter of the latency and packet drop rate. This Thesis focuses on the communication errors that appear on such realtime networks, from the point-of-view of automatic control. Specifically, it investigates the effects of packet drops in automatic control over fieldbuses, as well as the architectures and optimal techniques for their compensation. Firstly, a new approach to address the problems that rise in virtue of such packet drops, is proposed. This novel approach is based on the simultaneous transmission of several values in a single message. Such messages can be from sensor to controller, in which case they are comprised of several past sensor readings, or from controller to actuator in which case they are comprised of estimates of several future control values. A series of tests reveal the advantages of this approach. The above-explained approach is then expanded as to accommodate the techniques of contemporary optimal control. However, unlike the aforementioned approach, that deliberately does not send certain messages in order to make a more efficient use of network resources; in the second case, the techniques are used to reduce the effects of packet losses. After these two approaches that are based on data aggregation, it is also studied the optimal control in packet dropping fieldbuses, using generalized actuator output functions. This study ends with the development of a new optimal controller, as well as the function, among the generalized functions that dictate the actuator’s behaviour in the absence of a new control message, that leads to the optimal performance. The Thesis also presents a different line of research, related with the output oscillations that take place as a consequence of the use of classic co-design techniques of networked control. The proposed algorithm has the goal of allowing the execution of such classical co-design algorithms without causing an output oscillation that increases the value of the cost function. Such increases may, under certain circumstances, negate the advantages of the application of the classical co-design techniques. A yet another line of research, investigated algorithms, more efficient than contemporary ones, to generate task execution sequences that guarantee that at least a given number of activated jobs will be executed out of every set composed by a predetermined number of contiguous activations. This algorithm may, in the future, be applied to the generation of message transmission patterns in the above-mentioned techniques for the efficient use of network resources. The proposed task generation algorithm is better than its predecessors in the sense that it is capable of scheduling systems that cannot be scheduled by its predecessor algorithms. The Thesis also presents a mechanism that allows to perform multi-path routing in wireless sensor networks, while ensuring that no value will be counted in duplicate. Thereby, this technique improves the performance of wireless sensor networks, rendering them more suitable for control applications. As mentioned before, this Thesis is centered around techniques for the improvement of performance of distributed control systems in which several elements are connected through a fieldbus that may be subject to packet drops. The first three approaches are directly related to this topic, with the first two approaching the problem from an architectural standpoint, whereas the third one does so from more theoretical grounds. The fourth approach ensures that the approaches to this and similar problems that can be found in the literature that try to achieve goals similar to objectives of this Thesis, can do so without causing other problems that may invalidate the solutions in question. Then, the thesis presents an approach to the problem dealt with in it, which is centered in the efficient generation of the transmission patterns that are used in the aforementioned approaches.

Classificação Internacional de Funcionalidade, Incapacidade e Saúde : uma dimensão do neurodesenvolvimento

RESUMO: Objetivo Principal • Determinar a consistência da utilização dos instrumentos de avaliação da capacidade intelectual – escalas de Griffiths e WISC III – no enquadramento dos domínios e dos qualificadores da CIF-CJ, restrita às funções mentais do corpo. Objetivo secundário: • Estudar a efetividade e concordância inter-observador da aplicação da CIF, com base na leitura dos dados obtidos em avaliação efetuada com os instrumentos referidos, por duas observadoras independentes, em contexto de articulação saúde, respetivamente educação e segurança social Métodos • Estudo observacional, descritivo, transversal e prospetivo. • Foi estudada uma amostra de conveniência 355 crianças, num período de três anos (Maio de 2010 a 30 de Abril de 2013), com patologia da área da pediatria do neurodesenvolvimento (total de 4000 consultas) no Centro de Desenvolvimento (CD) do Hospital de Dona Estefânia (HDE), Centro Hospitalar de Lisboa Central, EPE (CHLC, EPE). • Critérios de inclusão: crianças de ambos os sexos, observadas no CD do HDE, CHLC (primeiras consultas e consultas de reavaliação) com idade ≥12 meses e ≤17 anos e incapacidade intelectual definida de acordo com os critérios da DSM-IV-TR, DSM 5 e CID-10. • Critérios de exclusão: crianças com autismo, perturbações específicas da linguagem, hiperatividade, défice de atenção e concentração, défices sensoriais congénitos (baixa visão e ou audição), ou com outros diagnósticos de perturbações de neurodesenvolvimento. • O estudo teve duas fases: na primeira, a investigadora principal colheu ou atualizou a história clínica, observou clinicamente as crianças solicitando os exames complementares considerados necessários e foi efetuada avaliação psicológica com os instrumentos adiante descritos, pela mesma psicóloga clínica, devidamente credenciada, e com larga experiência nas escalas referidas. Com base nos dados colhidos, quer por observação direta, quer através dos resultados das escalas Griffiths e WISC – III, a investigadora aplicou a CIF-CJ, circunscrita aos domínios e funções (variáveis): 1. FUNÇÕESMENTAIS GLOBAIS (b110- Funções da consciência, b114- Funções da orientação no espaço e no tempo, b117 – Funções intelectuais, b122- Funções psicossociais globais, b125- Funções intrapessoais, b126- Funções do temperamento e da personalidade); 2.FUNÇÕES MENTAIS ESPECÌFICAS (b140- funções da atenção, b147- Funções psicomotoras, b152- Funções emocionais, b156- Funções da perceção, b163- Funções cognitivas básicas, b164- Funções cognitivas de nível superior, b167- Funções mentais da linguagem 3. FUNÇÕES DA VOZ E DA FALA (b320- Funções da articulação, b330- Funções da fluência e do ritmo da fala). Numa segunda fase, foi solicitada a colaboração de duas co-investigadoras, com formação específica nas escalas utilizadas e na CIF-CJ, a aplicação da CIF nos mesmos domínios e funções. Estas observadoras não efetuaram observações diretas das crianças envolvidas. • Para efetuar a análise estatística e analisar a relação entre os qualificadores (0 a 4) das variáveis da CIF em estudo (b117, b122, b147, b163, b164, b167, b320 e b330) e os instrumentos psicométricos (escalas de Griffiths e WISC III), que constitui a primeira parte do estudo, recorreu-se à técnica estatística não paramétrica do coeficiente de correlação de Spearman, que quantifica a intensidade e sinal da eventual correlação existente entre as variáveis em estudo. • Para determinar as correlações referentes à segunda parte do estudo, foram utilizados os programas SPSS®, (IBM SPSS Statistics) e Statistica® (StatSoft, Inc., 2011). STATISTICA (data analysis software system, version 10. www.statsoft.com.), tendo-se dado preferência aos gráficos deste último. Resultados 1. Observou-se um predomínio do sexo masculino (relação de 1:1,9); relativamente à idade no momento de avaliação, 242 crianças (68,1%) tinham entre zero e seis anos e, dentro destas, a maioria (189) situava-se entre os três e os seis anos. 2. De acordo com a DSM-IV e DSM-5, 261 (73,4%) crianças apresentavam incapacidade intelectual ligeira. 3. A avaliação da competência intelectual pelas escalas de Ruth Griffiths e WISC III (QI), revelaram correlação negativa predominantemente forte e muito forte (índice de Spearman) com os qualificadores das funções do corpo estudadas (funções mentais, mentais específicas e da voz). Os resultados obtidos pela co-investigadora A foram sobreponíveis aos da investigadora principal. Os resultados obtidos pela co-investigadora B revelaram correlação negativa moderada e forte, correlação inferior à da investigadora principal; Conclusões Os resultados permitem inferir que as escalas de Ruth Griffiths e WISC-III são instrumentos adequados para caracterizar a incapacidade intelectual na CIF-CJ; a concordância inter-observador, moderada, nos qualificadores atribuídos nas funções em análise pela investigadora e co-investigadoras, permite concluir que as escalas de Ruth Griffiths e WISC IIIl são bons instrumentos para caracterizar os qualificadores nos domínios e funções estudados, por diferentes grupos de profissionais ligados à infância. Subsistem dificuldades na diferenciação entre qualificadores, designadamente entre os qualificadores 1 e 2, o que tem necessariamente implicações na elegibilidade das crianças para os apoios preconizados pelo DL 3/2008. ------------------------ ABSTRACT: Main objective • To determine the consistency of the use of assessment tools for intellectual ability - Griffiths and WISC III scales - in the context of domains and qualifiers for the ICF-CY, restricted to the mental functions of the body. Secondary objective • Studying the effectiveness and inter-observer concordance concerning the application of the ICF, based on the data recovered from the assessment made with the mentioned instruments, carried out by two independent observers including their perspective on health, education and social security. Methods • Observational, descriptive, cross-sectional and prospective study. • A convenience sample of 355 children was studied over a period of three years (May 2010 to April 2013), with a pathology in the area of pediatric neurodevelopment – intellectual disability (total of 4000 consultations, including first consultations and revaluations) were observed in the Development Centre (CD) in Hospital de Dona Estefânia (HDE), Centro Hospitalar de Lisboa Central, EPE (CHLC). • Inclusion criteria: children of both sexes aged ≥12 months and years ≤17 and intellectual disability defined according to the criteria in the DSM-IV-TR, DSM 5 and ICD-10. • Exclusion criteria: children with autism; specific language impairment, hyperactivity; attention deficit disorder; severe birth sensory deficits (eg, impaired vision and hearing); amongst other diagnoses for neurodevelopmental disorders. • The study was conducted in two phases: in the first phase the principal investigator collected or updated medical history, clinically observed children requesting additional investigations if she deemed necessary. Psychological evaluation was performed by a single, duly licensed clinical psychologist with extensive experience in the referred scales using the instruments described below. Based on data collected, either by direct observation or through the results of Griffiths scales and WISC - III, the researcher applied the ICF-CY confined to the following fields and functions (variables): 1. GLOBAL MENTAL FUNCTIONS (b110- functions of consciousness, b114- Functions referring to space and time orientation , b117 - intellectual functions, b122- global psychosocial functions, b125- intrapersonal functions, b126- functions related to temperament and personality); 2. SPECIFIC MENTAL FUNCTIONS ( b140- attention functions, b147-psychomotor functions, b152- Emotional functions, b156- perception functions, b163- basic cognitive functions and cognitive functions b164- top level b167- language related mental functions. ) 3. VOICE AND SPEECH FUNCTIONS (b320-articulation functions, b330- fluency and rhythm of speech functions). • In the second phase, two co-investigators, with specific training on the scales used and the ICF-CY have applied the ICF in the domains and functions mentioned above, based on the scales results. These co-investigators did not make any direct observation of the studied children. • To perform the statistical analysis and analyze the relationship between the qualifiers (0-4) of the variables in the ICF study (b117, b122, b147, B163, B164, b167, b320 and B330) and psychometric instruments (Griffiths scale and WISC III), which is the first part of the study, the statistical technique of non-parametric Spearman correlation coefficient was used, which quantifies the strength and sign of the possible correlation between the variables under study. • For submission of correlations related to the second part of the study, SPSS (IBM SPSS) and Statistica (StatSoft, Inc., 2011) programs were used. STATISTICA (data analysis software system, version 10 www.statsoft.com.). Preference was given to graphs computed in Statistica. Results • Male predominated (ratio of 1: 1.9). 242 children (68.1% of the sample) were aged between zero and six years and, among these, the majority (189) was aged largest number between three and six years. • According to the DSM-IV and DSM-5, 261 (73.4%) children had mild intellectual disability. The correlation between the assessment of intellectual competence by Ruth Griffiths scales and WISC III (QI), was predominantly negative strong and very strong correlation with the qualifiers of body functions studied (specific mental functions, mental and voice functions using Spearman index). The levels of correlation obtained by the co-investigatores were in agreeance with the results from the principal investigator. The results obtained by co-investigator B showed moderate to strong negative correlation, levels that were lower to the those registered by the principal investigator; Conclusions These results indicate that Ruth Griffiths and WISC-III scales are adequate tools to characterize intellectual disability in the ICF-CY; moderate inter-observer agreement in the qualifiers assigned the functions under analysis by the researcher and co-researchers, shows that the scales are also good tools to measure CIF qualifyers by diferent technicians with different professional orientations, related to children. However, there are still difficulties in differentiating qualifiers, namely between qualifiers 1/2 and 3/4, which necessarily has implications for the eligibility of children for the state support advocated by the Portuguese Decret Law 3/2008.

Théorèmes de point fixe et principe variationnel d'Ekeland

Le principe de contraction de Banach, qui garantit l'existence d'un point fixe d'une contraction d'un espace métrique complet à valeur dans lui-même, est certainement le plus connu des théorèmes de point fixe. Dans plusieurs situations concrètes, nous sommes cependant amenés à considérer une contraction qui n'est définie que sur un sous-ensemble de cet espace. Afin de garantir l'existence d'un point fixe, nous verrons que d'autres hypothèses sont évidemment nécessaires. Le théorème de Caristi, qui garantit l'existence d'un point fixe d'une fonction d'un espace métrique complet à valeur dans lui-même et respectant une condition particulière sur d(x,f(x)), a plus tard été généralisé aux fonctions multivoques. Nous énoncerons des théorèmes de point fixe pour des fonctions multivoques définies sur un sous-ensemble d'un espace métrique grâce, entre autres, à l'introduction de notions de fonctions entrantes. Cette piste de recherche s'inscrit dans les travaux très récents de mathématiciens français et polonais. Nous avons obtenu des généralisations aux espaces de Fréchet et aux espaces de jauge de quelques théorèmes, dont les théorèmes de Caristi et le principe variationnel d'Ekeland. Nous avons également généralisé des théorèmes de point fixe pour des fonctions qui sont définies sur un sous-ensemble d'un espace de Fréchet ou de jauge. Pour ce faire, nous avons eu recours à de nouveaux types de contractions; les contractions sur les espaces de Fréchet introduites par Cain et Nashed [CaNa] en 1971 et les contractions généralisées sur les espaces de jauge introduites par Frigon [Fr] en 2000.

Orthogonal polynomials and recurrence equations, operator equations and factorization

This article surveys the classical orthogonal polynomial systems of the Hahn class, which are solutions of second-order differential, difference or q-difference equations. Orthogonal families satisfy three-term recurrence equations. Example applications of an algorithm to determine whether a three-term recurrence equation has solutions in the Hahn class - implemented in the computer algebra system Maple - are given. Modifications of these families, in particular associated orthogonal systems, satisfy fourth-order operator equations. A factorization of these equations leads to a solution basis.

A generic formula for the values at the boundary points of monic classical orthogonal polynomials

In a previous paper we have determined a generic formula for the polynomial solution families of the well-known differential equation of hypergeometric type σ(x)y"n(x)+τ(x)y'n(x)-λnyn(x)=0. In this paper, we give another such formula which enables us to present a generic formula for the values of monic classical orthogonal polynomials at their boundary points of definition.