A Participação Portuguesa em Programas Comunitários e de Cooperação Internacional

A evolução das sociedades dos últimos anos deste século tem tido fortes repercussões sociais, económicas e políticas. Como se afirma no Livro Branco da Comissão Europeia, sobre educação e formação Ensinar e Aprender - Rumo à Sociedade Cognitiva, o mundo atravessa um período de profundas transformações no contexto da actividade económica e das relações sociais, constituindo este final de século uma fase de rápida transição para uma nova era de mundialização das relações e de globalização da informação, de que o acelerado progresso científico e técnico tem sido o principal suporte

Stochastic Lag Time in Nucleated Linear Self-Assembly

Protein aggregation is of great importance in biology, e.g., in amyloid fibrillation. The aggregation processes that occur at the cellular scale must be highly stochastic in nature because of the statistical number fluctuations that arise on account of the small system size at the cellular scale. We study the nucleated reversible self-assembly of monomeric building blocks into polymer-like aggregates using the method of kinetic Monte Carlo. Kinetic Monte Carlo, being inherently stochastic, allows us to study the impact of fluctuations on the polymerisation reactions. One of the most important characteristic features in this kind of problem is the existence of a lag phase before self-assembly takes off, which is what we focus attention on. We study the associated lag time as a function of the system size and kinetic pathway. We find that the leading order stochastic contribution to the lag time before polymerisation commences is inversely proportional to the system volume for large-enough system size for all nine reaction pathways tested. Finite-size corrections to this do depend on the kinetic pathway

Path integrals for stiff polymers applied to membrane physics

Path integrals similar to those describing stiff polymers arise in the Helfrich model for membranes. We show how these types of path integrals can be evaluated and apply our results to study the thermodynamics of a minority stripe phase in a bulk membrane. The fluctuation induced contribution to the line tension between the stripe and the bulk phase is computed, as well as the effective interaction between the two phases in the tensionless case where the two phases have differing bending rigidities.Comment: 11 pages RevTex, 4 figure

Some observations on the renormalization of membrane rigidity by long-range interactions

We consider the renormalization of the bending and Gaussian rigidity of model membranes induced by long-range interactions between the components making up the membrane. In particular we analyze the effect of a finite membrane thickness on the renormalization of the bending and Gaussian rigidity by long-range interactions. Particular attention is paid to the case where the interactions are of a van der Waals type.Comment: 11 pages RexTex, no figure

A magnocellular contribution to conscious perception via temporal object segmentation

The human visual system is continuously confronted with dynamic visual input. One challenge that the visual system must solve, therefore, is recognizing when two distinct objects have appeared at a given location despite their brief presentation and rapid succession, that is, temporal object segmentation. Here we examined the role of magnocellular neurons in this process. We measured temporal object segmentation via object substitution masking (OSM), which reflects the failure to distinguish the target and mask as distinct objects through time. We isolated the selective role of magnocellular neurons by comparing performance under conditions of pulsed luminance pedestals, which are designed to saturate the magnocellular response, with that in a steady-pedestal condition that leaves both magnocellular and parvocellular channels available to process the target. Across two experiments, we found that OSM magnitude was enhanced under pulsed-pedestal conditions, in which the magnocellular response was impaired. This indicates that magnocellular neurons contribute to temporal object segmentation. Given that temporal object segmentation has consequences for which stimuli are consciously perceived, this demonstrates a functional mechanism via which magnocellular neurons contribute to determining the contents conscious perception. Implications for models of specialization of dorsal and ventral cortical streams are discussed.Discovery Early Career Researcher Award - Grant ID: DE140101734 [ 2014 - 2016

Monotherapy with major antihypertensive drug classes and risk of hospital admissions for mood disorders

Major depressive and bipolar disorders predispose to atherosclerosis, and there is accruing data from animal model, epidemiological, and genomic studies that commonly used antihypertensive drugs may have a role in the pathogenesis or course of mood disorders. In this study, we propose to determine whether antihypertensive drugs have an impact on mood disorders through the analysis of patients on monotherapy with different classes of antihypertensive drugs from a large hospital database of 525 046 patients with follow-up for 5 years. There were 144 066 eligible patients fulfilling the inclusion criteria: age 40 to 80 years old at time of antihypertensive prescription and medication exposure >90 days. The burden of comorbidity assessed by Charlson and Elixhauser scores showed an independent linear association with mood disorder diagnosis. The median time to hospital admission with mood disorder was 847 days for the 299 admissions (641 685 person-years of follow-up). Patients on angiotensin-converting enzyme inhibitors or angiotensin receptor blockers had the lowest risk for mood disorder admissions, and compared with this group, those on β-blockers (hazard ratio=2.11; [95% confidence interval, 1.12–3.98]; P=0.02) and calcium antagonists (2.28 [95% confidence interval, 1.13–4.58]; P=0.02) showed higher risk, whereas those on no antihypertensives (1.63 [95% confidence interval, 0.94–2.82]; P=0.08) and thiazide diuretics (1.56 [95% confidence interval, 0.65–3.73]; P=0.32) showed no significant difference. Overall, our exploratory findings suggest possible differential effects of antihypertensive medications on mood that merits further study: calcium antagonists and β-blockers may be associated with increased risk, whereas angiotensin-converting enzyme inhibitors and angiotensin receptor blockers may be associated with a decreased risk of mood disorders

Celebrating five years of innovative care in the community

The Eating Disorder Project (EDP) started as a one-year pilot project, commissioned by local GPs in a borough of London in January 2016.The idea actually sprouted when Miranda Boal now the service lead, left her post in a secondary care eating disorders service to help set something up in the community.Dr Martina Gerada tells us more

Threat Avoidance Behavior and Land Use of the Northern Bobwhite in the Rolling Plains of Texas

Northern bobwhites (Colinus virginianus) are an economically important species for several regions within the state of Texas. Bobwhites, along with their fiscal importance, fill a key role within the ecosystem as an r-selected common prey species. However, throughout the past few decades, bobwhite populations have plummeted to record lows. Currently many studies are investigating possible causes behind this precipitous decline, but efforts to discover better land management practices that provide preferred habitat for bobwhites should not be abandoned. Current landscape recommendations related to bobwhite escape cover stem from data collected on anthropogenic threats to bobwhites (i.e., coveys flushed by human disturbance). Bobwhites have a multitude of non-anthropogenic threats in the wild, and the existing data may lack important information regarding threat-specific avoidance behavior. Predation is a primary cause of bobwhite mortality, and we focused on bobwhite anti-predatory behavior and resulting land-use strategies with an ultimate goal of providing management recommendations to increase bobwhite survival. We designed and conducted an experiment to investigate not only bobwhite responses to anthropogenic threats, but also their responses to common natural predators. We investigated bobwhite behavioral and use of cover actions in response to 4 threat types: researchers, hunters, raptors, and nocturnal mammals. We collected data from January through March in 2010 and from November 2010 through March 2011. We measured characteristics of bobwhite flushing behavior, flight speed, and land and vegetative use when presented with specific threats. We located radio-marked coveys and conducted a walk-through for the researcher threat, if necessary, to cause the birds to flush. The hunter and raptor threats were conducted similarly with introduction of pointing dogs and shotgun blasts for the hunting scenario, and introduction of a trained northern goshawk (Accipiter gentilis) to give chase to bobwhites in the raptor scenario. We followed the same methods as the researcher treatment when creating the nocturnal mammal treatment, but conducted the test at night and followed the birds’ flight with a thermal imaging scope. There was a significant difference in landing cover among threat types with bobwhites selecting shrubs for landing cover when pursued by a raptor (P , 0.0001), whereas they showed no selection for shrubs when flushed by the other threat types. Bobwhites landed in live oak (Quercus virginianus) mottes and hackberry (Celtis reticulata) shrubs with the highest frequency, followed closely by wolfberry (Lycium barbarum), lote bush (Ziziphyus obtusifolia), and Englemann’s pricklypear (Opuntia engelmannii) when escaping the raptorial threat, These 5 species accounted for 49% of all shrubs used (19 total species) as escape cover in the raptor treatment. Obstructive vegetative height was higher at landing sites when bobwhites were presented with a raptor (P , 0.0001) or hunter (P 1⁄4 0.033) threat; however, bobwhites displayed no selection for obstructive vegetative height when presented with a researcher or nocturnal mammal threat. Further analyses will include modeling environmental and experimental parameters to find likely predictors of bobwhite threat avoidance behaviors, such as flushing speed, flight speed, and flight distance; behaviors that arguably affect energy expenditure and may interact with bobwhite health and predator avoidance capabilities. Our results suggest that land management recommendations based solely on anthropogenic threats may be insufficient to enable successful bobwhite escape strategies from raptors. Considering the availability and ‘integrity’ of shrubs as escape cover from raptors when contemplating brush management plans may enhance bobwhite management. We expect to provide threat-specific land management recommendations for bobwhites related to shrub species and density as well as grass density with continued analysis of these data

Spicules and the effect of rigid rods on enclosing membrane tubes

Membrane tubes (spicules) arise in cells, or artificial membranes, in the nonlinear deformation regime due to, e.g. the growth of microtubules, actin filaments or sickle hemoglobin fibers towards a membrane. We calculate the axial force exerted by the cylindrical membrane tube, and its average radius, by taking into account steric interactions between the fluctuating membrane and the enclosed rod. The force required to confine a fluctuating membrane near the surface of the enclosed rod diverges as the separation approaches zero. This results in a smooth crossover of the axial force between a square root and a linear dependence on the membrane tension as the tension increases and the tube radius shrinks. This crossover can occur at the most physiologically relevant membrane tensions. Our work may be important in (i) interpreting experiments in which axial force is related to the tube radius or membrane tension (ii) dynamical theories for biopolymer growth in narrow tubes where these fluctuation effects control the tube radius.Comment: 10 pages, 1 figur

Funciones y modos de oír música de niños y adolescentes, en distintos contextos

Este artículo presenta una investigación sobre funciones y modos de oír música de niños y adolescentes, en distintos contextos. Analiza por qué, cómo y con quién oyen los niños música, en los contextos socio-educativos casa y escuela, considerando su edad y desarrollo psicológico, así como perspectivas educacionales y culturales. Elaboramos una entrevista estructurada con cuestiones abiertas sobre el papel de la audición musical en las actividades diarias de los niños, comparando aspectos específicos de la audición en casa y en la escuela. Participaron 120 niños, provenientes de dos nacionalidades, británica y portuguesa, y dos grupos de edades correspondientes a niveles de enseñanza: 9-10 años, pertenecientes a escuelas primarias, y 13-14 anos, a escuelas secundarias.Los resultados destacan los factores del desarrollo, la influencia de los contextos sociales y educativos, la funcionalidad de oír música, y la visión dinámica de los modos de oír de los niños. En casa y en otros contextos informales, la música tiene principalmente funciones emocionales y sociales. En la escuela y en otros contextos formales, parece tener sobre todo funciones cognitivas, que pueden ser menos valoradas por los niños. En casa, los niños desarrollan una identidad personal y social, disfrutando de la música con la familia y los amigos, con quienes mantienen relaciones emocionales y sociales significativas, mientras que en la escuela conviven con los compañeros y los profesores. Los niños son conscientes de las diferencias entre los contextos casa y escuela, y atribuyen a las funciones sociales y emocionales de la música gran importancia, pudiendo ser ésta una razón para disfrutar menos de la música en la escuela.Abstract This study investigated functions and modes of music listening of children and adolescents, in different contexts, by focusing on why, how, and with whom children listen to music in the social-educational contexts home and school. It considered developmental, as well as educational and cultural perspectives, and it compared children from different age levels and nationalities. The 120 participants were British and Portuguese children aged 9-10 years, attending primary schools, and 13-14 years, attending secondary schools. A structured interview with open-ended questions asked about the role of music listening in children¿s everyday activities, comparing specific aspects of listening at home and at school.The results point to developmental factors, the influence of social and educational contexts, the functionality of music listening, and a dynamic view of children¿s modes of listening. At home and in other informal places, music listening has mainly emotional and social functions, whereas at school and in other formal contexts, it has mainly cognitive functions, which may not be so valued by children. At home, children develop their personal and social identity, enjoying music with family and friends, with whom they keep emotional and social relationships, whereas at school they interact with schoolmates and teachers. Children were well aware of the contextual differences 0 between home and school. The greater importance they attribute to the emotional and social functions of music may be a reason why they enjoy school music less