966 resultados para Recreation Specialization


Relevância:

10.00% 10.00%

Publicador:

Resumo:

SNARE protein-driven secretion of neurotransmitters from synaptic vesicles is at the center of neuronal communication. In the absence of the cytosolic protein Munc18-1, synaptic secretion comes to a halt. Although it is believed that Munc18-1 orchestrates SNARE complexes, its mode of action is still a matter of debate. In particular, it has been challenging to clarify the role of a tight Munc18/syntaxin 1 complex, because this interaction interferes strongly with syntaxin's ability to form a SNARE complex. In this complex, two regions of syntaxin, the N-peptide and the remainder in closed conformation, bind to Munc18 simultaneously. Until now, this binary complex has been reported for neuronal tissues only, leading to the hypothesis that it might be a specialization of the neuronal secretion apparatus. Here we aimed, by comparing the core secretion machinery of the unicellular choanoflagellate Monosiga brevicollis with that of animals, to reconstruct the ancestral function of the Munc18/syntaxin1 complex. We found that the Munc18/syntaxin 1 complex from M. brevicollis is structurally and functionally highly similar to the vertebrate complex, suggesting that it constitutes a fundamental step in the reaction pathway toward SNARE assembly. We thus propose that the primordial secretion machinery of the common ancestor of choanoflagellates and animals has been co-opted for synaptic roles during the rise of animals.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

In this issue, we take a closer look at the individual risk factors measured by the LSI-R. There are several risk factors that the LSI-R assessment tool measures: Criminal History; Education/Employment; Financial; Family/Marital; Accommodations (Living Situation); Leisure/Recreation; Companions; Alcohol/Drug Problem; Emotional/Personal; and Attitudes/Orientation.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

The stable co-existence of two haploid genotypes or two species is studied in a spatially heterogeneous environment submitted to a mixture of soft selection (within-patch regulation) and hard selection (outside-patch regulation) and where two kinds of resource are available. This is analysed both at an ecological time-scale (short term) and at an evolutionary time-scale (long term). At an ecological scale, we show that co-existence is very unlikely if the two competitors are symmetrical specialists exploiting different resources. In this case, the most favourable conditions are met when the two resources are equally available, a situation that should favour generalists at an evolutionary scale. Alternatively, low within-patch density dependence (soft selection) enhances the co-existence between two slightly different specialists of the most available resource. This results from the opposing forces that are acting in hard and soft regulation modes. In the case of unbalanced accessibility to the two resources, hard selection favours the most specialized genotype, whereas soft selection strongly favours the less specialized one. Our results suggest that competition for different resources may be difficult to demonstrate in the wild even when it is a key factor in the maintenance of adaptive diversity. At an evolutionary scale, a monomorphic invasive evolutionarily stable strategy (ESS) always exists. When a linear trade-off exists between survival in one habitat versus that in another, this ESS lies between an absolute adjustment of survival to niche size (for mainly soft-regulated populations) and absolute survival (specialization) in a single niche (for mainly hard-regulated populations). This suggests that environments in agreement with the assumptions of such models should lead to an absence of adaptive variation in the long term.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

The University of Iowa Office of the State Archaeologist (OSA) is delighted to welcome RAGBRAI riders to Iowa and we’re pleased to share a few details of our fascinating past as you ride across the state. We hope this booklet enhances your enjoyment and helps you learn something new each day of your ride, from the ancient site at Cherokee to the late 1800s lost town site of Bowen’s Prairie.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Want to know what conditions to expect over the next stage of RAGBRAI? How hilly will it be, what towns and parks are between here and there, or what services are coming up in the next town?

Relevância:

10.00% 10.00%

Publicador:

Resumo:

The University of Iowa Office of the State Archaeologist and Team Archaeology are back on RAGBRAI for another year of Archaeology on the Road, and pleased to partner this year with the IDNR: Geological and Water Survey and the U.S. Geological Survey under the theme “Human and Natural History Partners.” Archaeology on the Road brings you the unique cultural history and prehistory of Iowa on the RAGBRAI route, pointing out interesting and significant archaeological sites and sharing Iowa’s past along the way. Look for our booth at Expo and then again on Days 1, 5 and 6 on the route, and also keep an eye out for our Team Archaeology

Relevância:

10.00% 10.00%

Publicador:

Resumo:

The University of Iowa Office of the State Archaeologist and Team Archaeology are back on RAGBRAI for another year of Archaeology on the Road, and pleased to partner this year with the IDNR: Geological and Water Survey and the U.S. Geological Survey under the theme “Human and Natural History Partners.” Archaeology on the Road brings you the unique cultural history and prehistory of Iowa on the RAGBRAI route, pointing out interesting and significant archaeological sites and sharing Iowa’s past along the way. Look for our booth at Expo and then again on Days 1, 5 and 6 on the route, and also keep an eye out for our Team Archaeology

Relevância:

10.00% 10.00%

Publicador:

Resumo:

The University of Iowa Office of the State Archaeologist and Team Archaeology are back on RAGBRAI for another year of Archaeology on the Road, and pleased to partner this year with the IDNR: Geological and Water Survey and the U.S. Geological Survey under the theme “Human and Natural History Partners.” Archaeology on the Road brings you the unique cultural history and prehistory of Iowa on the RAGBRAI route, pointing out interesting and significant archaeological sites and sharing Iowa’s past along the way. Look for our booth at Expo and then again on Days 1, 5 and 6 on the route, and also keep an eye out for our Team Archaeology

Relevância:

10.00% 10.00%

Publicador:

Resumo:

The University of Iowa Office of the State Archaeologist and Team Archaeology are back on RAGBRAI for another year of Archaeology on the Road, and pleased to partner this year with the IDNR: Geological and Water Survey and the U.S. Geological Survey under the theme “Human and Natural History Partners.” Archaeology on the Road brings you the unique cultural history and prehistory of Iowa on the RAGBRAI route, pointing out interesting and significant archaeological sites and sharing Iowa’s past along the way. Look for our booth at Expo and then again on Days 1, 5 and 6 on the route, and also keep an eye out for our Team Archaeology.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

The University of Iowa Office of the State Archaeologist and Team Archaeology are back on RAGBRAI for our third year of Archaeology on the Road, and pleased to partner this year with the IDNR: Geological and Water Survey and the U.S. Geological Survey under the theme “Human and Natural History Partners.” Archaeology on the Road brings you the unique cultural history and prehistory of Iowa on the RAGBRAI route, pointing out interesting and significant archaeological sites and sharing Iowa’s past along the way. Look for our booth at Expo and then again on Days 1, 5 and 6 on the route, and also keep an eye out for our Team Archaeology

Relevância:

10.00% 10.00%

Publicador:

Resumo:

The University of Iowa Office of the State Archaeologist and Team Archaeology are back on RAGBRAI for our third year of Archaeology on the Road, and pleased to partner this year with the IDNR: Geological and Water Survey and the U.S. Geological Survey under the theme “Human and Natural History Partners.” Archaeology on the Road brings you the unique cultural history and prehistory of Iowa on the RAGBRAI route, pointing out interesting and significant archaeological sites and sharing Iowa’s past along the way. Look for our booth at Expo and then again on Days 1, 5 and 6 on the route, and also keep an eye out for our Team Archaeology.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Background: Chemoreception is a widespread mechanism that is involved in critical biologic processes, including individual and social behavior. The insect peripheral olfactory system comprises three major multigene families: the olfactory receptor (Or), the gustatory receptor (Gr), and the odorant-binding protein (OBP) families. Members of the latter family establish the first contact with the odorants, and thus constitute the first step in the chemosensory transduction pathway.Results: Comparative analysis of the OBP family in 12 Drosophila genomes allowed the identification of 595 genes that encode putative functional and nonfunctional members in extant species, with 43 gene gains and 28 gene losses (15 deletions and 13 pseudogenization events). The evolution of this family shows tandem gene duplication events, progressive divergence in DNA and amino acid sequence, and prevalence of pseudogenization events in external branches of the phylogenetic tree. We observed that the OBP arrangement in clusters is maintained across the Drosophila species and that purifying selection governs the evolution of the family; nevertheless, OBP genes differ in their functional constraints levels. Finally, we detect that the OBP repertoire evolves more rapidly in the specialist lineages of the Drosophila melanogaster group (D. sechellia and D. erecta) than in their closest generalists.Conclusion: Overall, the evolution of the OBP multigene family is consistent with the birth-and-death model. We also found that members of this family exhibit different functional constraints, which is indicative of some functional divergence, and that they might be involved in some of the specialization processes that occurred through the diversification of the Drosophila genus.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

BACKGROUND: In Canada, many health authorities recommend that primary care physicians (PCP) stay involved throughout their patients' cancer journey to increase continuity of care. Few studies have focused on patient and physician expectations regarding PCP involvement in cancer care. OBJECTIVE: To compare lung cancer patient, PCP and specialist expectations regarding PCP involvement in coordination of care, emotional support, information transmission and symptom relief at the different phases of cancer. DESIGN: Canadian survey of lung cancer patients, PCPs and cancer specialists PARTICIPANTS: A total of 395 patients completed questionnaires on their expectations regarding their PCP participation in several aspects of care, at different phases of their cancer. Also, 45 specialists and 232 community-based PCP involved in these patients' care responded to a mail survey on the same aspects of cancer care. RESULTS: Most specialists did not expect participation of the PCP in coordination of care in the diagnosis and treatment phases (65% and 78% respectively), in contrast with patients (83% and 85%) and PCPs (80% and 59%) (p < 0.0001). At these same phases, the best agreement among the 3 groups was around PCP role in emotional support: 84% and more of all groups had this expectation. PCP participation in symptom relief was another shared expectation, but more unanimously at the treatment phase (p = 0.85). In the advanced phase, most specialists expect a major role of PCP in all aspects of care (from 81% to 97%). Patients and PCP agree with them mainly for emotional support and information transmission. CONCLUSION: Lung cancer patient, PCP and specialist expectations regarding PCP role differ with the phase of cancer and the specific aspect of cancer care. There is a need to reach a better agreement among them and to better define PCP role, in order to achieve more collaborative and integrated cancer care.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

In severe and variable conditions, specialized resource selection strategies should be less fre‐ quent because extinction risks increase for species that depend on a single and unstable resource. Psithyrus (Bombus subgenus Psithyrus) are bumblebee parasites that usurp Bombus nests and display inter‐specific variation in the number of hosts they parasitize. Using a phylogenetic comparative frame‐ work, we show that Psithyrus species at higher elevations display a higher number of hosts species com‐ pared with species restricted to lower elevations. Species inhabiting high elevations also cover a larger temperature range, suggesting that species able to occur in colder conditions may benefit from recruit‐ ment from populations occurring in warmer conditions. Our results provide evidence for an 'altitudinal niche breadth hypothesis' in parasitic species, showing a decrease in the parasites' specialization along the elevational gradient, and also suggesting that Rapoport's rule might apply to Psithyrus.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

The splenium of the corpus callosum connects the posterior cortices with fibers varying in size from thin late-myelinating axons in the anterior part, predominantly connecting parietal and temporal areas, to thick early-myelinating fibers in the posterior part, linking primary and secondary visual areas. In the adult human brain, the function of the splenium in a given area is defined by the specialization of the area and implemented via excitation and/or suppression of the contralateral homotopic and heterotopic areas at the same or different level of visual hierarchy. These mechanisms are facilitated by interhemispheric synchronization of oscillatory activity, also supported by the splenium. In postnatal ontogenesis, structural MRI reveals a protracted formation of the splenium during the first two decades of human life. In doing so, the slow myelination of the splenium correlates with the formation of interhemispheric excitatory influences in the extrastriate areas and the EEG synchronization, while the gradual increase of inhibitory effects in the striate cortex is linked to the local inhibitory circuitry. Reshaping interactions between interhemispherically distributed networks under various perceptual contexts allows sparsification of responses to superfluous information from the visual environment, leading to a reduction of metabolic and structural redundancy in a child's brain.