988 resultados para diesel common rail albero motore
Resumo:
The purpose of the experiment was to compare the level of synchronization exhibited by pairs of motor units located within and between functionally distinct regions of the biceps brachii muscle. Pairs of single motor units were recorded from seven subjects using separate electrodes located in the lateral and medial aspects of the long head of biceps brachii. Participants were required to exert a combination of flexion and supination torques so that both motor units discharged at approximately 10 pps for a parts per thousand yen200 s and the level of motor unit synchronization could be quantified. When motor unit recordings were sufficiently stable at the completion of this synchrony task, a series of ramp contractions with multiple combinations of flexion and supination torques were performed to characterize the recruitment thresholds of the motor units. Common input strength (CIS) was significantly greater (P <0.01) for the within-region pairs of motor units (0.28 extra sync. imps/s, n = 26) than for the between-region pairs (0.13 extra sync. imps/s, n = 18), but did not differ significantly for the 12 within-region pairs from the lateral head and 14 from the medial head (0.27 vs. 0.29 extra sync. imps/s; P = 0.83). Recruitment thresholds were measured for 33 motor units, but there was only a weak association between CIS and the respective recruitment patterns for motor unit pairs (n = 9). The present investigation provides evidence of a differential distribution of synaptic input across the biceps brachii motor neuron pool, but this appears to have minimal association with the recruitment patterns for individual motor units.
Resumo:
Ionic liquids generally have wide liquid ranges and negligible vapour pressures; attractive characteristics for use as media for heat transfer and short heat term storage systems. This review of the limited literature available shows that many common ionic liquids have heat capacities, and thus potential thermal energy storage capabilities, that surpass those of commercial hot-oil and synthetic heat transfer fluids and suggests that there is a role for ionic liquids as novel thermal fluids.
Resumo:
The common lizard (Zootoca vivipara) is Ireland’s only native reptile, forming a key part of the island’s biodiversity. However, there is a general paucity of distributional and abundance data for the species. In this study, we collated incidental records for common lizard sightings to define the distribution of the species in Northern Ireland. Maximum entropy modelling was employed to describe species-habitat associations. The resulting predicted landscape favourability was used to evaluate the current status of the species based on the distribution of its maximum potential range in relation to the degree of fragmentation of remaining suitable habitat. In common with previous studies in the Republic of Ireland, sightings were highly clustered indicating under-recording, observer bias, and fragmentation of suitable habitat. A total of 98 records were collated from 1905 to 2009. The species was recorded in 63 (ca. 34%) of 186 × 10 km Northern Irish grid squares. Lizard occurrence was strongly and positively associated with landscapes dominated by heathland, bog and coastal habitats. The single best approximating model correctly classified the presence of lizards in 84.2% of cases. Upland heath, lowland raised bog and sand dune systems are all subject to Habitat Action Plans in Northern Ireland and are threatened by conversion to agriculture, afforestation, invasive species encroachment and infrastructural development. Consequently, remaining common lizard populations are likely to be small, isolated and highly fragmented. Establishment of an ecological network to preserve connectivity of remaining heath and bog will not only benefit remaining common lizard populations but biodiversity in general.
Resumo:
This paper reports on a study of the ways in which 54 older people in South Wales (UK) talk about the symptoms and causes of cold and influenza (flu). The study was designed to understand why older people might reject or accept the offer of seasonal flu vaccine, and in the course of the interviews respondents were also asked to express their views about the nature and causes of the two key illnesses. The latter are among the most common infections in human beings. In terms of the biomedical paradigm the common cold is caused by numerous respiratory viruses, whilst flu is caused by the influenza virus. Medical diagnosis is usually made on clinical grounds without laboratory confirmation. Symptoms of flu include sudden onset of fever and cough, and colds are characterized by sneezing, sore throat, and runny nose, but in practice the symptoms often overlap. In this study we examine the degree by which the views of lay people with respect to both diagnosis and epidemiology diverge with that which is evident in biomedical discourse. Our results indicate that whilst most of the identified symptoms are common to lay and professional people, the former integrate symptoms into a markedly different observational frame from the latter. And as far as causation is concerned it is clear that lay people emphasize the role of 'resistance' and 'immunity' at least as much as 'infection' in accounting for the onset of colds and flu. The data are analyzed using novel methods that focus on the co-occurrence of concepts and are displayed as semantic networks. As well as reporting on its findings the authors draw out some implications of the study for social scientific and policy discussions concerning lay diagnosis, lay expertise and the concept of an expert patient.