1,100 research outputs found

    Technical quality assessment of an optoelectronic system for movement analysis

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    The Optoelectronic Systems (OS) are largely used in gait analysis to evaluate the motor performances of healthy subjects and patients. The accuracy of marker trajectories reconstruction depends on several aspects: the number of cameras, the dimension and position of the calibration volume, and the chosen calibration procedure. In this paper we propose a methodology to evaluate the eects of the mentioned sources of error on the reconstruction of marker trajectories. The novel contribution of the present work consists in the dimension of the tested calibration volumes, which is comparable with the ones normally used in gait analysis; in addition, to simulate trajectories during clinical gait analysis, we provide non-default paths for markers as inputs. Several calibration procedures are implemented and the same trial is processed with each calibration le, also considering dierent cameras congurations. The RMSEs between the measured trajectories and the optimal ones are calculated for each comparison. To investigate the signicant dierences between the computed indices, an ANOVA analysis is implemented. The RMSE is sensible to the variations of the considered calibration volume and the camera congurations and it is always inferior to 43 mm

    Components of Purity to Describe the Polarimetric State of a 3-D Field Within the Reverberating Chamber

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    Reverberating chambers (RCs) are electrically large microwave enclosures in which a random electromagnetic 3-D, i.e., nonplanar, field is generated. To characterize such 3-D fields, a proper polarimetric decomposition is requested. In this article, a new set of parameters, namely the components of purity (CP), first proposed to the electromagnetic compatibility community, is presented. The CP parameters, which stem for the so-called trivial decomposition, are able to classify any 3-D polarimetric field into two states: regular and nonregular. Such characterization is of practical relevance, e.g., for RC isotropy testing

    Progressive Dysphasic Dementia with Bucco-Facial Apraxia: A Case Report

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    A patient with progressive dementia, prominent non-fluent aphasia and signs of frontal lobe involvement, was evaluated by neuropsychological testing, magnetic resonance imaging (MRI) and high resolution single photon emission tomography (SPET). The presence of severe bucco-facial apraxia, associated with spared imitation of limb movements, correlated well with a marked reduction of cerebral perfusion in the left fronto-temporal cortex. This case emphasizes the usefulness of SPET as a valuable alternative to PET for the diagnosis of conditions, such as progressive neuropsychological syndromes, where a coupled reduction of metabolism and blood flow can be expected

    Increased immunocompetence and network centrality of allogroomer workers suggest a link between individual and social immunity in honeybees.

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    The significant risk of disease transmission has selected for effective immune-defense strategies in insect societies. Division of labour, with individuals specialized in immunity-related tasks, strongly contributes to prevent the spread of diseases. A trade-off, however, may exist between phenotypic specialization to increase task efficiency and maintenance of plasticity to cope with variable colony demands. We investigated the extent of phenotypic specialization associated with a specific task by using allogrooming in the honeybee, Apis mellifera, where worker behaviour might lower ectoparasites load. We adopted an integrated approach to characterize the behavioural and physiological phenotype of allogroomers, by analyzing their behavior (both at individual and social network level), their immunocompetence (bacterial clearance tests) and their chemosensory specialization (proteomics of olfactory organs). We found that allogroomers have higher immune capacity compared to control bees, while they do not differ in chemosensory proteomic profiles. Behaviourally, they do not show differences in the tasks performed (other than allogrooming), while they clearly differ in connectivity within the colonial social network, having a higher centrality than control bees. This demonstrates the presence of an immune-specific physiological and social behavioural specialization in individuals involved in a social immunity related task, thus linking individual to social immunity, and it shows how phenotypes may be specialized in the task performed while maintaining an overall plasticity

    Efectos del entrenamiento de fuerza integrado dos veces por semana en jóvenes

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    La aptitud física es uno de los factores más importante para prevenir las enfermedades cardiovasculares La fuerza es uno de los componentes más influyentes sobre la aptitud física. Objetivo: Se estudió un grupo de 21 varones (V) y 11 mujeres (M) jóvenes, al cual se aplicó un programa de entrenamiento de fuerza integrado durante 7 semanas, con una frecuencia de 2 días semanales. Método: Se evaluó la fuerza máxima a través de una repetición máxima (1RM) en los ejercicios de press de banca (PB) y ¿ sentadilla (SEN). El entrenamiento consistió en aplicar intensidades del 45 al 90% y volúmenes de 10 a 18 repeticiones por ejercicio, saltos y pliometría. Resultados: Se encontraron diferencias significativas p< 0.01 pre y post entrenamiento, PB en V 57.9 + 7.2 vs 65 + 8.2 Kg; SEN en V 84.1 + 15.3 vs 101.1 + 16.1 Kg; PB en M 38.5 + 8.6 vs 47.4 + 6.7 Kg SEN en M 61.8 + 15.1 vs 80.3 + 13.7 Kg. Conclusión: El entrenamiento de dos veces a la semana con un programa de fuerza integrado, durante 7 semanas incrementa la fuerza en forma significativa en jóvenes sanos de ambos

    Wastewater disposal and earthquake swarm activity at the southern end of the Central Valley, California

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    Fracture and fault zones can channel fluid flow and transmit injection-induced pore pressure changes over large distances (>km), at which seismicity is rarely suspected to be human induced. We use seismicity analysis and hydrogeological models to examine the role of seismically active faults in inducing earthquakes. We analyze a potentially injection-induced earthquake swarm with three events above M4 near the White Wolf fault (WWF). The swarm deviates from classic main aftershock behavior, exhibiting uncharacteristically low Gutenberg-Richter b of 0.6, and systematic migration patterns. Some smaller events occurred southeast of the WWF in an area of several disposal wells, one of which became active just 5 months before the main swarm activity. Hydrogeological modeling revealed that wastewater disposal likely contributed to seismicity via localized pressure increase along a seismically active fault. Our results suggest that induced seismicity may remain undetected in California without detailed analysis of local geologic setting, seismicity, and fluid diffusion

    Immunity of honeybee guards reflects their transition from house bees to foragers

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    Eusocial insect colonies represent some of the most extreme examples of specialized division of labor. Ageing in workers is often associated with a temporal polyethism in the tasks performed both inside and outside the colony. Such behavioral transition is sometimes linked to a gradual reduction in individual immunity. Here, we studied the immune ability of Apis mellifera guard bees, which represent an intermediate stage between house bees working inside the nest and foragers collecting resources outside, to assess if their specific task is associated with an immune specialization. Through immune challenge with Gram-negative bacteria Escherichia coli, we compared the guards ability to clear bacterial cells from their haemolymph with respect to house bees and foragers. Our findings demonstrate that guards do not show an immune specialization linked to their task but seem to represent a transition also in terms of immunity, since their anti-bacterial response appears intermediate between house bees and foragers
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