Using mouse dynamics to assess stress during online exams

"Lecture notes in computer science series", ISSN 0302-9743, vol. 9121

Fundamental concepts in multibody dynamics

In this chapter, the fundamental ingredients related to formulation of the equations of motion for multibody systems are described. In particular, aspects such as degrees of freedom, types of coordinates, basic kinematics joints and types of analysis in multibody systems are briefly characterized. Illustrative examples of application are also presented to better clarify the fundamental issues for spatial rigid multibody systems, which are of crucial importance in the formulation development of mathematical models of mechanical systems, as well as its computational implementation.

Introduction [to Contact force models for multibody dynamics]

"Series: Solid mechanics and its applications, vol. 226"

Numerical methods in multibody system dynamics

"Series: Solid mechanics and its applications, vol. 226"

Contact force models for multibody dynamics

"Series: Solid mechanics and its applications, vol. 226"

On the frictional contacts in multibody system dynamics

"Series title: Computational methods in applied sciences, ISSN1871-3033, vol. 42"

The electoral dynamics of human development

This paper analyses the impact of elections on the dynamics of human development in a panel of 82 countries over the period 1980-2013. The incidence of partisan and political support effects is also taken into account. A GMM estimator is employed in the empirical analysis and the results point out to the presence of an electoral cycle in the growth rate of human development. Majority governments also influence it, but no clear evidence is found regarding partisan effects. The electoral cycles have proved to be stronger in non-OECD countries, in countries with less frequent elections, with lower levels of income and human development, in presidential and non-plurality systems and in proportional representation regimes. They have also become more intense in this millennium.

Role of sirtuin 3 on mitochondrial dynamics in Huntington's disease striatal cells

Disserta����o de mestrado em Gen��tica Molecular

Development of a subject-specific musculoskeletal shoulder model : inverse and forward dynamics applications

A preval��ncia de pessoas que referem dor no complexo articular do ombro, com concomitante limita����o na capacidade para realizar atividades da vida di��ria, �� elevada. Estes n��veis de preval��ncia sobrecarregam quer os utentes, como a pr��pria sociedade. A evid��ncia cient��fica atual indicia a exist��ncia de uma rela����o entre as altera����es da articula����o esc��pulo-tor��cica e as patologias associadas �� articula����o gleno-umeral. A capacidade de quantificar, cinem��tica e cineticamente, as disfun����es ao n��vel das articula����es esc��pulo-tor��cica e gleno-umeral, �� algo de enorme import��ncia, quer para a comunidade biomec��nica, como para a cl��nica. No decorrer dos trabalhos desta tese foi desenvolvido, atrav��s do software OpenSim, um modelo tridimensional m��sculo-esquel��tico do complexo articular do ombro que inclui a representa����o do t��rax/coluna, clav��cula, omoplata, ��mero, r��dio, c��bito e articula����es que permitem os movimentos relativos desses segmentos, assim como, 16 m��sculos e 4 ligamentos. Com um total de 11 graus de liberdade, incluindo um novo modelo articular esc��pulo-tor��cico, os resultados demonstram que este �� capaz de reconstruir de forma precisa e r��pida os movimentos esc��pulo-tor��cicos e glenoumerais, recorrendo para tal, �� cinem��tica inversa, e �� din��mica inversa e direta. Conta ainda com um m��todo de transforma����o inovador para determinar, com base nas especificidades dos sujeitos, os locais de inser����o muscular. As principais motiva����es subjacentes ao desenvolvimento desta tese foram contribuir para o aprofundar do atual conhecimento sobre as disfun����es do complexo articular do ombro e, simultaneamente, proporcionar �� comunidade cl��nica uma ferramenta biomec��nica de livre acesso com o intuito de melhor suportar as decis��es cl��nicas e dessa forma concorrer para uma pr��tica mais efetiva.

Manipulaci��n acustica del orden y din��mica molecular en estructuras mesomorficas de organizaci��n lamelar. Acoustic manipulation of molecular order and dynamics in mesomorphic structures of lamellar organization.

El control de propiedades hidrodin��micas capaces de influir en la mec��nica de ruptura y poraci��n de sistemas lamelares o membranas es de fundamental inter��s para diferentes aplicaciones biotecnol��gicas. Resulta de particular inter��s la conexi��n entre los procesos microsc��picos relacionados al tipo de mol��culas o unidades b��sicas, el orden determinado en el auto-ensamblado de las mismas y la din��mica local del sistema, con las propiedades f��sicas que determinan el comportamiento macrosc��pico bajo estimulaci��n ac��stica. Resultados logrados recientemente sugieren la existencia de resonancias hidrodin��micas que podrian ser utilizadas para lograr la inestabilidad del sistema a baja potencia ac��stica. Se realizaran estudios experimentales utilizando principalmente t��cnicas que combinan resonancia magn��tica nuclear (RMN) y la sonicaci��n de la muestra. Tambi��n se realizar��n estudios te��ricos y simulaciones num��ricas que permitan modelar los sistemas bajo estudio. Se propone dar continuidad al desarrollo de una t��cnica de relaxometr��a magn��tica nuclear en la cual se estimula ac��sticamente a la muestra durante el proceso de relajaci��n magn��tica nuclear, y continuar la implementaci��n de t��cnicas de RMN con resoluci��n espacial que permitan complementar los estudios mencionados. Se espera comprender los mecanismos f��sicos que determinan la estabilidad de fases lamelares, logrando un modelo verificable y consistente que permita relacionar las propiedades mec��nicas e hidrodin��micas con las propiedades de orden y din��mica molecular. Asimismo, se espera lograr avances en el desarrollo de las t��cnicas experimentales involucradas. La importancia del proyecto radica en el enfoque del problema. A diferencia de casi la totalidad de los estudios reportados, nuestro inter��s se enfoca en mecanismos de interacci��n entre la membrana y el campo ac��stico que sean eficientes a baja potencia ac��stica, en un r��gimen donde los gradientes t��rmicos y la cavitaci��n sean despreciables.

Din��mica Cu��ntica de Sistemas Complejos: Fundamentos y Aplicaciones. Quantum Dynamics in Complex Systems: Fundamentals and Aplications.

El procedimiento de revertir la din��mica colectiva (diablillo de Loschmidt apresurado) mediante un pulso de radio frecuencia, permite generar un Eco de Loschmidt, es decir la refocalizaci��n de una excitaci��n localizada. Alternativamente, en ac��stica es posible implementar un Espejo de Reversi��n Temporal, que consiste en la progresiva inyecci��n de una d��bil excitaci��n ultras��nica en la periferia de un sistema, para construir una excitaci��n que se propaga "hacia atr��s". As��, podemos afirmar que es posible revertir y controlar la din��mica. Sin embargo, a��n no se posee una comprensi��n detallada de los mecanismos que gobiernan estos procedimientos. Este proyecto busca responder las preguntas que posibilitan esta comprensi��n.

Din��mica poblacional de Streptococcus mutans en ni��os de edad escolar de la provincia de C��rdoba. Population dynamics of Streptococcus mutans in school age children in the province of C��rdoba

La caries dental es una enfermedad infecciosa, cr��nica y trasmisible, que se caracteriza por la desmineralizaci��n de los tejidos duros del diente, producida por la acci��n de los ��cidos resultantes de la actividad metab��lica del biofilm desarrollado sobre los dientes. Si bien, la etiolog��a de la caries ser��a polimicrobiana, los estreptococos del grupo mutans son se��alados como los principales protagonistas en el inicio de la lesi��n cariosa. En la pared celular se destacan prote��nas que participan en procesos de adhesi��n, agregaci��n y co-agregaci��n, adem��s de polisac��ridos que muestran distintas especificidades antig��nicas, lo que permite distinguir cuatro serotipos: c, e, f y k. Es escasa la informaci��n de las caracter��sticas antig��nicas de las cepas circulantes de estreptococos del grupo mutans y se desconoce la relaci��n de las mismas con la actividad de caries. En este estudio nuestros objetivos son identificar y caracterizar fenot��pica y genot��picamente las cepas de estreptococos del grupo mutans circulantes en la provincia de C��rdoba. La poblaci��n de estudio estar�� constituida por escolares, urbano���marginales de la capital y del interior de la provincia. Se determinar��n los serotipos de las mismas a trav��s de de amplificaciones por PCR de tipo multiplex y luego se secuenciar��n 8 genes a trav��s de la t��cnica de tipado multilocus, con el fin de realizar estudios de sistem��tica molecular, y de estimar la estructura gen��tica de S. mutans. Una vez que se hayan caracterizado los patrones de diversidad y distribuci��n geogr��fica de S. mutans del centro de Argentina, se intentar�� dilucidar c��mo se relacionan la diversidad gen��tica con la experiencia de caries de los ni��os del estudio. Se analizar��n de forma conjunta nuestros resultados con los publicados por otros autores. De esta forma se lograr�� una mejor comprensi��n de los factores hist��ricos y ecol��gicos que han moldeado su distribuci��n y aportar conocimientos a la sistem��tica del grupo ���mutans��� en relaci��n a otras bacterias del g��nero Streptococcus. Dental caries is an infectious, chronic and transmissible disease, characterized by demineralization of the hard tissues of the teeth, produced by the action of acids resulting from the metabolic activity of biofilm developed on the teeth. Although the etiology of caries would be polymicrobial, the streptococci of the mutans group are identified as the major responsible in the initiation of the carious lesion. In the cell wall there are proteins involved in adhesion, aggregation and co-aggregation processes, as well as polysaccharides that present different antigenic specificities, which allow the distinction of four serotypes c, e, f and k. There is little information about the antigenic characteristics of the Streptococcus mutans strains and the relationship of those characteristics with the caries activity is unknown. In the present study our goals are to identify and characterize the phenotypic and genotypic strains of streptococci of the mutans group circulating in the province of Cordoba. The study population will consist of urban and rural scholar children from Cordoba city and from the interior of the province. In order to study the molecular systematic, and the genetic structure of S. mutans, different serotypes will be determined by multiplex PCR amplifications and eight genes will be sequenced by using the multilocus typing technique. Once the diversity and the geographical distribution patterns of S. mutans from the center of Argentina is characterized, we will attempt to clarify how the genetic diversity is related with the caries experience in the children of the study. Our results will be analyzed together with those published by other authors. This will achieve a better understanding of the historical and ecological factors that shaped the bacteria���s distribution and will contribute to the knowledge of the systematic of the mutans group in relation to other bacteria of the genus Streptococcus.

Din��mica y cin��tica de los procesos f��sicos y qu��micos del radical OH con compuestos org��nicos vol��tiles (COVs) de relevancia atmosf��rica. Dynamics and kinetics of the physical and chemical processes of OH radicals with atmospheric relevant volatile organic compounds (VOCs)

El objetivo del presente proyecto es estudiar los procesos f��sicos y qu��micos del radical OH con compuestos org��nicos vol��tiles (COVs), con los cuales sea factible la formaci��n de agregados de van der Waals (vdW) responsables de la curvatura en los gr��ficos de Arrhenius, empleando t��cnicas modernas, complementarias entre si y novedosas en el pa��s. El problema ser�� abordado desde tres perspectivas complementarias: 1) estudios cin��ticos, 2) estudios mecan��sticos y de distribuci��n de productos y 3) estudios de la din��mica de los procesos f��sicos y qu��micos. La finalidad es alcanzar una mejor comprensi��n de los mecanismos que intervienen en el comportamiento qu��mico de especies presentes en la atm��sfera y obtener datos cin��ticos de alta calidad que puedan alimentar modelos computacionales capaces de describir la composici��n de la atm��sfera, presente y futura. Los objetivos son estudiar: 1) mediante fot��lisis l��ser pulsada con detecci��n por fluorescencia inducida por l��ser (PLP-LIF), en reactores de flujo, la cin��tica de reacci��n del radical OH(v���=0) con COVs que presentan gr��ficos de Arrhenius curvos con energ��as de activaci��n negativas, tales como alcoholes insaturados, alquenos halogenados, ��teres halogenados, ��steres alif��ticos; 2) en una c��mara de simulaci��n de condiciones atmosf��ricas de gran volumen (4500 L), la identidad y el rendimiento de productos de las reacciones mencionadas, a fines de evaluar su impacto atmosf��rico y dilucidar los mecanismos de reacci��n; 3) mediante haces moleculares y espectroscop��a l��ser, la estructura y reactividad de complejos de vdW entre alcoholes insaturados o arom��ticos (cresoles) y el radical OH, como modelo de los aductos propuestos como responsables de la desviaci��n al comportamiento de Arrhenius de las reacciones mencionadas; 4) mediante PLP-LIF y expansiones supers��nicas, las constantes espec��ficas estado a estado (ksts) de relajaci��n/reacci��n del radical OH(v���=1-4) vibracionalmente excitado con los COVs mencionados. Los resultados experimentales obtenidos ser��n contrastados con c��lculos ab-initio de estructura electr��nica, los cuales apoyar��n las interpretaciones, permitir��n proponer estructuras de estados de transici��n y aductos colisionales, como as�� tambi��n calcular las frecuencias de vibraci��n de los complejos de vdW para su posterior asignaci��n en los espectros LIF y REMPI. Asimismo, los mecanismos de reacci��n propuestos y los par��metros cin��ticos medidos experimentalmente ser��n comparados con aquellos obtenidos por c��lculos te��ricos. The aim of this project is to study the physical and chemical processes of OH radicals with volatile organic compounds (VOCs) with which the formation of van der Waals (vdW) clusters, responsible for the observed curvature in the Arrhenius plots, might be feasible. The problem will be addressed as follow : 1) kinetic studies; 2) products distribution and mechanistic studies and 3) dynamical studies of the physical and chemical processes. The purpose is to obtain a better understanding of the mechanisms that govern the chemical behavior of species present in the atmosphere and to obtain high quality kinetic data to be used as input to computational models. We will study: 1) the reaction kinetics of OH (v���=0) radicals with VOCs such as unsaturated alcohols, halogenated alkenes, halogenated ethers, aliphatic esters, which show curved Arrhenius plots and negative activation energies, by PLP-LIF, in flow systems; 2) in a large volume (4500 L) atmospheric simulation chamber, reaction products yields in order to evaluate their atmospheric impact and reaction mechanisms; 3) using molecular beams and laser spectroscopy, the structure and reactivity of the vdW complexes formed between the unsaturated or aromatic alcohols and the OH radicals as a model of the adducts proposed as responsible for the non-Arrhenius behavior; 4) the specific state-to-state relaxation/reaction rate constants (ksts) of the vibrationally excited OH (v���=1-4) radical with the VOCs by PLP-LIF and supersonic expansions. Ab-initio calculations will be carried out to support the interpretation of the experimental results, to obtain the transition state and collisional adducts structures, as well as to calculate the vibrational frequencies of the vdW complexes to assign to the LIF and REMPI spectra. Also, the proposed reaction mechanisms and the experimentally measured kinetic parameters will be compared with those obtained from theoretical calculations.

Population dynamics of O-group plaice, Pleuronectes platessa L., on sandy beach nursery grounds in Galway Bay, the West Coast of Ireland, 2002 to 2006.

The recruitment of 0-group plaice to sandy beach nursery grounds in Galway Bay was examined, using a Riley push-net, from February to June in 2005 and 2006. Sampling was carried out every two weeks on spring tides. Three beaches were sampled, Ballyloughan, Silverstrand and Glann na Ri. Archived 0-group plaice, for Ballyloughan and Silverstrand, from 2004, were processed. Results were compared to findings from a previous study carried out in 2002 and 2003 (Allen 2004). Otolith microstructure analysis was used to determine hatching dates, larval duration, settlement dates, post-larval age and daily growth rates of 0-group plaice in April and May 2005. Results were compared to a previous study (Allen 2004). Hatching dates in Galway Bay ranged from late January to early April in 2005. No significant difference in hatching dates was observed between years or between beaches sampled. Larval duration of 0-group plaice in Galway Bay ranged from 21 to 45 days for fish sampled in April and May 2005. No significant difference was observed in larval age between beaches sampled in Galway Bay or between years in April 2003 and 2005. A significant difference was observed between larval age and years in May 2003 and 2005, however no significant difference was observed between beaches. Settlement timing was calculated using push-net data and otolith microstructure analysis. Settlement of 0-group plaice in Galway Bay generally started in early March and finished in May. Settlement patterns, calculated using otolith microstructure analysis, in 2003 and 2005, were not significantly different to one another. There was also no difference in settlement patterns between the beaches sampled. Results from the present study showed no spatial difference in the pelagic life cycle stages of fish caught in April and May 2003 and 2005.