Sökresultat

Filtyp

Din sökning på "*" gav 529814 sökträffar

Experimental facilitation of heat loss affects work rate and innate immune function in a breeding passerine bird

The capacity to get rid of excess heat produced during hard work is a possible constraint on parental effort during reproduction [heat dissipation limit (HDL) theory]. We released hard-working blue tits (Cyanistes caeruleus) from this constraint by experimentally removing ventral plumage. We then assessed whether this changed their reproductive effort (feeding rate and nestling size) and levels ofThe capacity to get rid of excess heat produced during hard work is a possible constraint on parental effort during reproduction [heat dissipation limit (HDL) theory]. We released hard-working blue tits (Cyanistes caeruleus) from this constraint by experimentally removing ventral plumage. We then assessed whether this changed their reproductive effort (feeding rate and nestling size) and levels of

Age differences in night-time metabolic rate and body temperature in a small passerine

Spending the winter in northern climes with short days and cold ambient temperatures (Ta) can be energetically challenging for small birds that have high metabolic and heat loss rates. Hence, maintaining body temperature (Tb) in Ta below thermoneutrality can be energetically costly for a small bird. We still know little about how increased heat production below thermoneutrality affects the level aSpending the winter in northern climes with short days and cold ambient temperatures (Ta) can be energetically challenging for small birds that have high metabolic and heat loss rates. Hence, maintaining body temperature (Tb) in Ta below thermoneutrality can be energetically costly for a small bird. We still know little about how increased heat production below thermoneutrality affects the level a

Reduced immune responsiveness contributes to winter energy conservation in an Arctic bird

Animals in seasonal environments must prudently manage energyexpenditure to survive the winter. This may be achieved throughreductions in the allocation of energy for various purposes (e.g.thermoregulation, locomotion, etc.). We studied whether such tradeoffsalso include suppression of the innate immune response, bysubjecting captive male Svalbard ptarmigan (Lagopus mutahyperborea) to bacterial liAnimals in seasonal environments must prudently manage energyexpenditure to survive the winter. This may be achieved throughreductions in the allocation of energy for various purposes (e.g.thermoregulation, locomotion, etc.). We studied whether such tradeoffsalso include suppression of the innate immune response, bysubjecting captive male Svalbard ptarmigan (Lagopus mutahyperborea) to bacterial li

Proliferation and benevolence—A framework for dissecting the mechanisms of microbial virulence and health promotion

Key topics in the study of host–microbe interactions—such as the prevention of drug resistance and the exploitation of beneficial effects of bacteria—would benefit from concerted efforts with both mechanistic and evolutionary approaches. But due to differences in intellectual traditions, insights gained in one field rarely benefit the other. Here, we develop a conceptual and analytical framework f

Night conditions affect morning incubation behaviour differently across a latitudinal gradient

Intermittently incubating birds alternate between sessions of egg warming and recesses for foraging during the day, but stay on the nest continuously at night. Hence, energy costs of nocturnal incubation (which increase during longer and colder nights) cannot be replenished until the next day. Night conditions might therefore be expected to affect morning incubation behaviour the day after. We tesIntermittently incubating birds alternate between sessions of egg warming and recesses for foraging during the day, but stay on the nest continuously at night. Hence, energy costs of nocturnal incubation (which increase during longer and colder nights) cannot be replenished until the next day. Night conditions might therefore be expected to affect morning incubation behaviour the day after. We tes

Multivariate Analysis of Orthogonal Range Searching and Graph Distances

We show that the eccentricities, diameter, radius, and Wiener index of an undirected n-vertex graph with nonnegative edge lengths can be computed in time O(n·(k+⌈logn⌉k)·2klogn), where k is linear in the treewidth of the graph. For every ϵ> 0 , this bound is n1 + ϵexp O(k) , which matches a hardness result of Abboud et al. (in: Proceedings of the Twenty-Seventh Annual ACM-SIAM Symposium on Discret

A new maximal bicycle test using a prediction algorithm developed from four large COPD studies

Background: Maximum exercise workload (WMAX) is today assessed as the first part of Cardiopulmonary Exercise testing. The WMAX test exposes patients with COPD, often having cardiovascular comorbidity, to risks. Our research project was initiated with the final aim to eliminate the WMAX test and replace this test with a predicted value of WMAX, based on a prediction algorithm of WMAX derived from m

Perceived Barriers to Decision Quality in Three Swedish Public Authorities

Barriers to decision quality were reported by 473 administrative officers and investigators in three Swedish national public authorities: the Tax Agency, Social Insurance Agency, and Police Authority. In line with previous research, we assumed that limited possibilities to plan one’s work would hinder decision quality. Both disruption of workflow and high workload were reported to inhibit work pla

Optimization study on periodic counter-current chromatography integrated in a monoclonal antibody downstream process

An optimization study of an integrated periodic counter-current chromatography (PCC) process in a monoclonal antibody (mAb) downstream process at lab scale, is presented in this paper. The optimization was based on a mechanistic model of the breakthrough curve in the protein-A capture step. Productivity and resin utilization were the objective functions, while yield during the loading of the captu

Phase-field fracture modelling of crack nucleation and propagation in porous rock

In this work, we suggest a modified phase-field model for simulating the evolution of mixed mode fractures and compressive driven fractures in porous artificial rocks and Neapolitan Fine Grained Tuff. The numerical model has been calibrated using experimental observations of rock samples with a single saw cut under uniaxial plane strain compression. For the purpose of validation, results from the

Cellular and molecular mechanisms in immune mediated hepatic fibrosis. A study of the inflammatory syndrome and fibrosis development of the NIF mouse liver.

Fibrosis is the result of dysregulated inflammation and tissue repair, and is characterized by the excessive accumulation of extra cellular matrix (ECM) proteins. It causes detrimental effects to the afflicted tissue and can subsequently lead to organ failure. Sterile liver inflammation and hepatic fibrosis are associated with many liver disorders of different etiologies. Both type 1 and type 2 in

Partitioning variation in multilevel models for count data

A first step when fitting multilevel models to continuous responses is to explore the degree of clustering in the data. Researchers fit variance-component models and then report the proportion of variation in the response that is due to systematic differences between clusters. Equally they report the response correlation between units within a cluster. These statistics are popularly referred to as