Symmetric Brownian motor

In this paper, we present a model of a symmetric Brownian motor which changes the sign of its velocity when the temperature gradient is inverted. The velocity, external work, and efficiency are studied as a function of the temperatures of the baths and other relevant parameters. The motor shows a current reversal when another parameter (a phase shift) is varied. Analytical predictions and results from numerical simulations are performed and agree very well. Generic properties of this type of motor are discussed.

Modeling a processive molecular motor: the conventional kinesin

We present a model that allows for the derivation of the experimentally accesible observables: spatial steps, mean velocity, stall force, useful power, efficiency and randomness, etc. as a function of the [adenosine triphosphate] concentration and an external load F. The model presents a minimum of adjustable parameters and the theoretical predictions compare well with the available experimental results.

TrkB signaling is required for postnatal survival of CNS neurons and protects hippocampal and motor neurons from axotomy-induced cell death

Newborn mice carrying targeted mutations in genes encoding neurotrophins or their signaling Trk receptors display severe neuronal deficits in the peripheral nervous system but not in the CNS. In this study, we show that trkB (¿/¿) mice have a significant increase in apoptotic cell death in different regions of the brain during early postnatal life. The most affected region in the brain is the dentate gyrus of the hippocampus, although elevated levels of pyknotic nuclei were also detected in cortical layers II and III and V and VI, the striatum, and the thalamus. Furthermore, axotomized hippocampal and motor neurons of trkB (¿/¿) mice have significantly lower survival rates than those of wild-type littermates. These results suggest that neurotrophin signaling through TrkB receptors plays a role in the survival of CNS neurons during postnatal development. Moreover, they indicate that TrkB receptor signaling protects subpopulations of CNS neurons from injury- and axotomy-induced cell death.

Proposta i implementació d'un motor de recuperació d'informació especialitzat en dret d'estrangeria (Codex)

CODEX SEARCH és un motor de recuperació d'informació especialitzat en dret d'estrangeria que està basat en eines i coneixement lingüístics. Per a desenvolupar un SRI (sistema de recuperació d'informació) eficient en el domini indicat no n'hi ha prou amb emprar un model tradicional de RI (recuperació d'informació), és a dir, comparar els termes de la pregunta amb els de la resposta, bàsicament perquè no expressen implicacions. En aquest sentit, la solució lingüística proposada es basa a incorporar el coneixement dels especialistes mitjançant la integració en el sistema d'una llibreria de casos. Els casos són exemples de procediments aplicats per experts/ertes en la solució de problemes que han ocorregut en la realitat i que han acabat en èxit o fracàs. Els resultats obtinguts en aquesta primera fase són molt encoratjadors, però és necessari continuar la investigació en aquest camp per millorar el rendiment del prototip.

Models teòrics explicatius de l'aprenentatge motor

En este artículo se repasan los principales modelos teóricos explicativos del aprendizaje motor. En un primer apartado se comentan las aportaciones propias de la psicología cognitiva y más concretamente del corriente del procesamiento de la información: la Teoría del bucle cerrado de Jack Adams y la Teoría del esquema de Richard Schmidt. Posteriormente, se exponen las críticas que han recibido estos modelos y, para hacerlo, se introducen las principales aportaciones que el científico ruso Nikolai Bernstein hizo al estudio del aprendizaje y el control motor. A partir de estas aportaciones, se introducen las formulaciones teóricas que, surgidas desde la perspectiva dinámica-ecológica, pretenden superar las limitaciones de los modelos cognitivos. Finalmente, se comparan las dos perspectivas y se sugieren algunas posibles vías de desarrollo futuro del campo que nos ocupa.

La actividad productiva de la fábrica de harinas “La Montserrat” (Girona) en el año agrícola de 1903-1904 = The Production Activities at the Company Harinera “La Montserrat” (Girona) over the Agricultural Year 1903-1904

Harinera La Montserrat, S.A, a company involved in the manufacturing and trading of cereals and flour, was founded in Girona in 1898 by José Ensesa y Cía., Sociedad en Comandita. With the objective to determine how the product activity of this business was structured, we have studied in detail the operations that were carried out over the agricultural year 1903-1904. We have focused on three main aspects. Firstly, the purchasing of wheat (origin, transportation, prices); secondly, the production of flour (using internal and external wheat, profits); and thirdly, its distribution (customers, destination). Finally, we have analyzed the profit and loos account for this period in order to find out if this business was profitable

Desenvolupament d'un motor 2D per videojocs de plataformes mòbils

L’objectiu del projecte és la creació d’un motor gràfic id’esdeveniments per a jocs RPG per a plataformes mòbils, en aquest casper a Nintendo DS. S’ha de remarcar que el que s’està proposant no és laprogramació d’un videojoc, sinó que el que es desenvoluparà és el motorde joc. Aquest motor comptarà no solament amb la funcionalitat bàsica devisualització i animació d’escenaris i personatges, detecció de col•lisionsentre personatges i elements de l’escenari, sinó que a més, comptarà ambles funcionalitats pròpies dels jocs més sofisticats (esdeveniments). Aquestmotor és compatible per a Nintendo DS i/o qualsevol emulador d’aquestaplataforma per a PC

Surrealismo, Cultura de Masas y Moda: redefiniendoimágenes sociales durante el periodo de entreguerras

El siglo XX podría caracterizarse por su sobreproducción tanto de bienes de consumocomo de imágenes, gracias a los avances tecnológicos que tienen sus primeros orígenesen la Revolución Industrial. El nuevo siglo se presentaba como el escenario de unanueva sociedad que no tardaría en denominarse a sí misma Moderna. Además, trajoconsigo algo nunca antes visto: la producción en masa cuyo baluarte principal fueHenry Ford (1863 – 1947), fundador de la Ford Motor Company (1903 – ). Este nuevométodo de producción, que no tardó en ser absorbido por las distintas industrias (entreellas la de la moda y la prensa, como veremos), se caracterizaba por producir de manerarápida, efectiva y, sobre todo, a costos reducidos, un producto determinado en enormescantidades para satisfacer la demanda de esta nueva sociedad. Por otro lado, este tipo deproducción no daba cabida a demasiada variedad, por lo cual se homogeneizó la base deconsumo; es decir, muchos poseían copias genéricas de un mismo producto.

The Network Company in Catalonia : ICT, Productivity, Competitiveness, Salaries and Performance in Catalonia's Companies. Research report (synthesis document)

Resum en anglès del projecte de recerca L'empresa xarxa a Catalunya. TIC, productivitat, competitivitat, salaris i beneficis a l'empresa catalana té com a objectiu principal constatar que la consolidació d'un nou model estratègic, organitzatiu i d'activitat empresarial, vinculat amb la inversió i l'ús de les TIC (o empresa xarxa), modifica substancialment els patrons de comportament dels resultats empresarials, en especial la productivitat, la competitivitat, les retribucions dels treballadors i el benefici. La contrastació empírica de les hipòtesis de treball l'hem feta per mitjà de les dades d'una enquesta a una mostra representativa de 2.038 empreses catalanes. Amb la perspectiva de l'impacte de la inversió i l'ús de les TIC no s'aprecia una relació directa entre els processos d'innovació digital i els resultats de l'activitat de l'empresa catalana. En aquest sentit, hem hagut de segmentar el teixit productiu català per a buscar les organitzacions en què el procés de coinnovació tecnològica digital i organitzativa és més present i en què la intensitat de l'ús del coneixement és un recurs molt freqüent per a poder copsar impactes rellevants en els principals resultats empresarials. Això és així perquè l'economia catalana, avui, presenta una estructura productiva dual.

Differences based on fine motor behaviour in Parkinson's patients compared to an age matched control group in proprioceptive and visuo-proprioceptive test conditions

Personality differences based on fine motor precision performance were studied in early stage Parkinson's patients and an age-matched control group under two different test conditions: proprioceptive + visual information and proprioceptive information alone. A comparative data analysis for deviations of three measured movement types (transversal, frontal and sagittal) was done for both hands (dominant and non-dominant) with relation to personality dimensions. There were found significant differences between the two groups in decision making dimension and emotionality. After splitting the data for gender subgroups, some significant differences were found for men but not for women. The differences in fine motor task performance varied, being better in some directions for the Parkinson"s patients and worse in others. The findings may suggest that medication has both positive and negative effects on motor performance and provoke personality changes, being more pronounced in men.

A Threat to a Virtual Hand Elicits Motor Cortex Activation

We report an experiment where participants observed an attack on their virtual body as experienced in an immersive virtual reality (IVR) system. Participants sat by a table with their right hand resting upon it. In IVR, they saw a virtual table that was registered with the real one, and they had a virtual body that substituted their real body seen from a first person perspective. The virtual right hand was collocated with their real right hand. Event-related brain potentials were recorded in two conditions, one where the participant"s virtual hand was attacked with a knife and a control condition where the knife only struck the virtual table. Significantly greater P450 potentials were obtained in the attack condition confirming our expectations that participants had a strong illusion of the virtual hand being their own, which was also strongly supported by questionnaire responses. Higher levels of subjective virtual hand ownership correlated with larger P450 amplitudes. Mu-rhythm event-related desynchronization in the motor cortex and readiness potential (C3C4) negativity were clearly observed when the virtual hand was threatened as would be expected, if the real hand was threatened and the participant tried to avoid harm. Our results support the idea that event-related potentials may provide a promising non-subjective measure of virtual embodiment. They also support previous experiments on pain observation and are placed into context of similar experiments and studies of body perception and body ownership within cognitive neuroscience.

Prognostic value of cortically induced motor evoked activity by TMS in chronic stroke: caveats from a very revealing single clinical case

Background: We report the case of a chronic stroke patient (62 months after injury) showing total absence of motor activity evoked by transcranial magnetic stimulation (TMS) of spared regions of the left motor cortex, but near-to-complete recovery of motor abilities in the affected hand. Case presentation: Multimodal investigations included detailed TMS based motor mapping, motor evoked potentials (MEP), and Cortical Silent period (CSP) as well as functional magnetic resonance imaging (fMRI) of motor activity, MRI based lesion analysis and Diffusion Tensor Imaging (DTI) Tractography of corticospinal tract (CST). Anatomical analysis revealed a left hemisphere subinsular lesion interrupting the descending left CST at the level of the internal capsule. The absence of MEPs after intense TMS pulses to the ipsilesional M1, and the reversible suppression of ongoing electromyographic (EMG) activity (indexed by CSP) demonstrate a weak modulation of subcortical systems by the ipsilesional left frontal cortex, but an inability to induce efficient descending volleys from those cortical locations to right hand and forearm muscles. Functional MRI recordings under grasping and finger tapping patterns involving the affected hand showed slight signs of subcortical recruitment, as compared to the unaffected hand and hemisphere, as well as the expected cortical activations. Conclusions: The potential sources of motor voluntary activity for the affected hand in absence of MEPs are discussed. We conclude that multimodal analysis may contribute to a more accurate prognosis of stroke patients.

Un motor de cerca per a l'aualé

L'aualé és possiblement el joc de mancala més conegut. Essent un joc amb adversari i de suma nul·la que s'ha estudiat profusament en el marc de la intel·ligència artificial, fins a arribar a la solució d'una de les seves variants l'any 2002. El projecte plantejat se centra en l'estudi pràctic d'una variant d'aualé de més difícil solució, 'abapa', a través de l'elaboració i optimització d'un motor de cerca.

Dyrk1A is dynamically expressed on subsets of motor neurons and in the neuromuscular junction: possible role in Down syndrome

Individuals with Down syndrome (DS) present important motor deficits that derive from altered motor development of infants and young children. DYRK1A, a candidate gene for DS abnormalities has been implicated in motor function due to its expression in motor nuclei in the adult brain, and its overexpression in DS mouse models leads to hyperactivity and altered motor learning. However, its precise role in the adult motor system, or its possible involvement in postnatal locomotor development has not yet been clarified. During the postnatal period we observed time-specific expression of Dyrk1A in discrete subsets of brainstem nuclei and spinal cord motor neurons. Interestingly, we describe for the first time the presence of Dyrk1A in the presynaptic terminal of the neuromuscular junctions and its axonal transport from the facial nucleus, suggesting a function for Dyrk1A in these structures. Relevant to DS, Dyrk1A overexpression in transgenic mice (TgDyrk1A) produces motor developmental alterations possibly contributing to DS motor phenotypes and modifies the numbers of motor cholinergic neurons, suggesting that the kinase may have a role in the development of the brainstem and spinal cord motor system.

Effect of cattle on Salmonella carriage, diversity and antimicrobial resistance in free-ranging wild boar (Sus scrofa) in northeastern Spain

Salmonella is distributed worldwide and is a pathogen of economic and public health importance. As a multi-host pathogen with a long environmental persistence, it is a suitable model for the study of wildlife-livestock interactions. In this work, we aim to explore the spill-over of Salmonella between free-ranging wild boar and livestock in a protected natural area in NE Spain and the presence of antimicrobial resistance. Salmonella prevalence, serotypes and diversity were compared between wild boars, sympatric cattle and wild boars from cattle-free areas. The effect of age, sex, cattle presence and cattle herd size on Salmonella probability of infection in wild boars was explored by means of Generalized Linear Models and a model selection based on the Akaike’s Information Criterion. Prevalence was higher in wild boars co-habiting with cattle (35.67%, CI 95% 28.19–43.70) than in wild boar from cattle-free areas (17.54%, CI 95% 8.74–29.91). Probability of a wild boar being a Salmonella carrier increased with cattle herd size but decreased with the host age. Serotypes Meleagridis, Anatum and Othmarschen were isolated concurrently from cattle and sympatric wild boars. Apart from serotypes shared with cattle, wild boars appear to have their own serotypes, which are also found in wild boars from cattle-free areas (Enteritidis, Mikawasima, 4:b:- and 35:r:z35). Serotype richness (diversity) was higher in wild boars co-habiting with cattle, but evenness was not altered by the introduction of serotypes from cattle. The finding of a S. Mbandaka strain resistant to sulfamethoxazole, streptomycin and chloramphenicol and a S. Enteritidis strain resistant to ciprofloxacin and nalidixic acid in wild boars is cause for public health concern.