1000 resultados para Wood characteristics


Relevância:

20.00% 20.00%

Publicador:

Resumo:

In the mouse, the Grueneberg ganglion (GG) is an olfactory subsystem implicated both in chemo- and thermo-sensing. It is specifically involved in the recognition of volatile danger cues such as alarm pheromones and structurally-related predator scents. No evidence for these GG sensory functions has been reported yet in other rodent species. In this study, we used a combination of histological and physiological techniques to verify the presence of a GG and investigate its function in the rat, hamster, and gerbil comparing with the mouse. By scanning electron microscopy (SEM) and transmitted electron microscopy (TEM), we found isolated or groups of large GG cells of different shapes that in spite of their gross anatomical similarities, display important structural differences between species. We performed a comparative and morphological study focusing on the conserved olfactory features of these cells. We found fine ciliary processes, mostly wrapped in ensheating glial cells, in variable number of clusters deeply invaginated in the neuronal soma. Interestingly, the glial wrapping, the amount of microtubules and their distribution in the ciliary processes were different between rodents. Using immunohistochemistry, we were able to detect the expression of known GG proteins, such as the membrane guanylyl cyclase G and the cyclic nucleotide-gated channel A3. Both the expression and the subcellular localization of these signaling proteins were found to be species-dependent. Calcium imaging experiments on acute tissue slice preparations from rodent GG demonstrated that the chemo- and thermo-evoked neuronal responses were different between species. Thus, GG neurons from mice and rats displayed both chemo- and thermo-sensing, while hamsters and gerbils showed profound differences in their sensitivities. We suggest that the integrative comparison between the structural morphologies, the sensory properties, and the ethological contexts supports species-dependent GG features prompted by the environmental pressure.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Référence bibliographique : Rol, 57069

Relevância:

20.00% 20.00%

Publicador:

Resumo:

OBJECTIVES: To determine if adolescent onset systemic juvenile idiopathic arthritis (JIA) and adult onset Still's disease (AOSD) represent the same clinical continuum of disease. METHODS: Retrospective review of available clinical data on all pediatric and adult patients diagnosed with Still's disease within the last 10 years at a university hospital. Assessment of functional outcomes at last visit by clinical evaluation and HAQ or c-HAQ. RESULTS: Nine patients were identified as adolescent onset systemic JIA and were compared with 10 patients with AOSD (onset > 18 years old). No statistically significant differences were found between the two groups in terms of clinical presentation at onset and outcome at follow up. CONCLUSION: Adolescent patients presenting with systemic JIA have a disease onset and course undistinguishable from that of AOSD patients, suggesting that they represent a continuum of a single disease entity.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Three-dimensional segmented echo planar imaging (3D-EPI) is a promising approach for high-resolution functional magnetic resonance imaging, as it provides an increased signal-to-noise ratio (SNR) at similar temporal resolution to traditional multislice 2D-EPI readouts. Recently, the 3D-EPI technique has become more frequently used and it is important to better understand its implications for fMRI. In this study, the temporal SNR characteristics of 3D-EPI with varying numbers of segments are studied. It is shown that, in humans, the temporal variance increases with the number of segments used to form the EPI acquisition and that for segmented acquisitions, the maximum available temporal SNR is reduced compared to single shot acquisitions. This reduction with increased segmentation is not found in phantom data and thus likely due to physiological processes. When operating in the thermal noise dominated regime, fMRI experiments with a motor task revealed that the 3D variant outperforms the 2D-EPI in terms of temporal SNR and sensitivity to detect activated brain regions. Thus, the theoretical SNR advantage of a segmented 3D-EPI sequence for fMRI only exists in a low SNR situation. However, other advantages of 3D-EPI, such as the application of parallel imaging techniques in two dimensions and the low specific absorption rate requirements, may encourage the use of the 3D-EPI sequence for fMRI in situations with higher SNR.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

This study analyses gender inequalities in health among elderly people in Catalonia (Spain) by adopting a conceptual framework that globally considers three dimensions of health determinants : socio-economic position, family characteristics and social support. Data came from the 2006 Catalonian Health Survey. For the purposes of this study a sub-sample of people aged 65–85 years with no paid job was selected (1,113 men and 1,484 women). The health outcomes analysed were self-perceived health status, poor mental health status and long-standing limiting illness. Multiple logistic regression models separated by sex were fitted and a hierarchical model was fitted in three steps. Health status among elderly women was poorer than among the men for the three outcomes analysed. Whereas living with disabled people was positively related to the three health outcomes and confidant social support was negatively associated with all of them in both sexes, there were gender differences in other social determinants of health. Our results emphasise the importance of using an integrated approach for the analysis of health inequalities among elderly people, simultaneously considering socio-economic position, family characteristics and social support, as well as different health indicators, in order fully to understand the social determinants of the health status of older men and women.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Various compositions of synthetic calcium phosphates (CaP) have been proposed and their use has considerably increased over the past decades. Besides differences in physico-chemical properties, resorption and osseointegration, artificial CaP bone graft might differ in their resistance against biofilm formation. We investigated standardised cylinders of 5 different CaP bone grafts (cyclOS, chronOS (both β-TCP (tricalcium phosphate)), dicalcium phosphate (DCP), calcium-deficient hydroxyapatite (CDHA) and α-TCP). Various physico-chemical characterisations e.g., geometrical density, porosity, and specific surface area were investigated. Biofilm formation was carried out in tryptic soy broth (TSB) and human serum (SE) using Staphylococcus aureus (ATCC 29213) and S. epidermidis RP62A (ATCC 35984). The amount of biofilm was analysed by an established protocol using sonication and microcalorimetry. Physico-chemical characterisation showed marked differences concerning macro- and micropore size, specific surface area and porosity accessible to bacteria between the 5 scaffolds. Biofilm formation was found on all scaffolds and was comparable for α-TCP, chronOS, CDHA and DCP at corresponding time points when the scaffolds were incubated with the same germ and/or growth media, but much lower for cyclOS. This is peculiar because cyclOS had an intermediate porosity, mean pore size, specific surface area, and porosity accessible to bacteria. Our results suggest that biofilm formation is not influenced by a single physico-chemical parameter alone but is a multi-step process influenced by several factors in parallel. Transfer from in vitro data to clinical situations is difficult; thus, advocating the use of cyclOS scaffolds over the four other CaP bone grafts in clinical situations with a high risk of infection cannot be clearly supported based on our data.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Because of their beneficial impact on forest ecosystems, European red wood ants (Formica rufa group) are protected by law in many European countries and are considered to be among the most reliable bioindicators of forest stability. However, their taxonomy has been much debated and, unfortunately, it is too often neglected. This happens mainly because the morphology-based method for species delimitation requires lots of time and experience. We therefore employed 9 microsatellite loci and mitochondrial DNA (COI gene) to verify the power of genetic markers for red wood ant species delimitation and to investigate the cryptic diversity of these ants within the Eastern Swiss Alps. We analyzed 83 nests belonging to all red wood ant species that occur in the Swiss National Park area. Genetic data indicated that these species represent different genetic pools. Moreover, results showed that Formica aquilonia YARROW, 1955 and F. paralugubris SEIFERT, 1996 often hybridize within the Park, confirming that these two species are genetically very close and could have diverged only recently. Nevertheless, microsatellites also revealed that one entire population, located in the Minger Valley and morphologically identified as F. lugubris ZETTERSTEDT, 1838, is genetically different to all other analyzed F. lugubris populations found within the same area and to other red wood ant species. These findings, confirmed by mitochondrial DNA analyses, suggest the existence of a new cryptic species within the Eastern Swiss Alps. This putative cryptic species has been provisionally named F. lugubris-A2. These results have a great importance for future conservation plans, monitoring and evolutionary studies on these protected ants.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Bonding of wood with glue dates back to ancient times but has increased enormously over the past decades. This 2 page report explains the proper way to glue wood.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Clients' personality traits and individual characteristics, such as age, gender, reason for seeking counselling, and further compounding problems in their personal or academic lives, may pose risk factors that render career decision making difficult and may also impact the overall effectiveness of a career counselling intervention. Neuroticism and conscien- tiousness as well as clients' age and gender directly affected clients' satisfaction with life and certain aspects of their career indecision scores before participating in our short-term career counselling intervention. Career counsellors can use personality and career-specific and career-non-specific instruments to tailor career counselling interventions to meet clients' individual needs.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

One of the most important issues in portland cement concrete pavement research today is surface characteristics. The issue is one of balancing surface texture construction with the need for durability, skid resistance, and noise reduction. The National Concrete Pavement Technology Center at Iowa State University, in conjunction with the Federal Highway Administration, American Concrete Pavement Association, International Grinding and Grooving Association, Iowa Highway Research Board, and other states, have entered into a three-part National Surface Characteristics Program to resolve the balancing problem. As a portion of Part 2, this report documents the construction of 18 separate pavement surfaces for use in the first level of testing for the national project. It identifies the testing to be done and the limitations observed in the construction process. The results of the actual tests will be included in the subsequent national study reports.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

A cross-sectional, epidemiological study aimed to estimate the prevalence of burden among family caregivers of impaired elderly residents in the city of João Pessoa, and to identify associations between the mean burden and social and demographic characteristics of the elderly and the caregivers. A total number of 240 elderly residents in a previously drawn census tract participated in this research. The sample was composed of 52 elderly and their caregivers. For data collection, a questionnaire was applied with questions on social and demographic characteristics of elderly and caregivers, and the Burden Interview Scale was used. Results showed a high prevalence of burden among caregivers (84.6%), in which a statistically significant association was found with the following characteristics: retired elderly, elderly as head of family, spousal caregivers, and caregivers with less education. The findings of this study may contribute to the development of activities focused on formal and emotional support for the caregivers.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Formica lugubris and E paralugubris are sympatric sibling species of wood ants, both of which are widely distributed in Switzerland. Until 1996 they were considered the same species, E lugubris. To investigate whether the two species can be distinguished based on discrimination cues used by the workers we used the pupa-carrying test first introduced by Rainer Rosengren. In this test workers of discriminator colonies are faced with two kinds of pupae and their preferences for one of the types are recorded based on differential retrieval. Interspecific comparisons showed that ants preferred conspecific worker pupae to those of the sibling species regardless whether the pupae were con-colonial or hetero-colonial. Hence, this test can be used as a taxonomic tool to identify wood ants hardly distinguishable by morphological characters. In intraspecific comparisons the highly polygynous (many queens per colony) E paralugubris, the polygynous form of E lugubris and the monogynous (single queen per nest) to weakly polygynous form of E lugubris expressed different trends in their preference behaviour (with nestmate recognition in 14%, 20% and 31% of replicates, respectively). Only F paralugubris presented no significant nestmate recognition.