186 research outputs found
Spatial and Temporal Dynamics of Pacific Oyster Hemolymph Microbiota across Multiple Scales
Unveiling the factors and processes that shape the dynamics of host associated microbial communities (microbiota) under natural conditions is an important part of understanding and predicting an organism's response to a changing environment. The microbiota is shaped by host (i.e., genetic) factors as well as by the biotic and abiotic environment. Studying natural variation of microbial community composition in multiple host genetic backgrounds across spatial as well as temporal scales represents a means to untangle this complex interplay. Here, we combined a spatially-stratified with a longitudinal sampling scheme within differentiated host genetic backgrounds by reciprocally transplanting Pacific oysters between two sites in the Wadden Sea (Sylt and Texel). To further differentiate contingent site from host genetic effects, we repeatedly sampled the same individuals over a summer season to examine structure, diversity and dynamics of individual hemolymph microbiota following experimental removal of resident microbiota by antibiotic treatment. While a large proportion of microbiome variation could be attributed to immediate environmental conditions, we observed persistent effects of antibiotic treatment and translocation suggesting that hemolymph microbial community dynamics is subject to within-microbiome interactions and host population specific factors. In addition, the analysis of spatial variation revealed that the within-site microenvironmental heterogeneity resulted in high small-scale variability, as opposed to large-scale (between-site) stability. Similarly, considerable within-individual temporal variability was in contrast with the overall temporal stability at the site level. Overall, our longitudinal, spatially-stratified sampling design revealed that variation in hemolymph microbiota is strongly influenced by site and immediate environmental conditions, whereas internal microbiome dynamics and oyster-related factors add to their long-term stability. The combination of small and large scale resolution of spatial and temporal observations therefore represents a crucial but underused tool to study host-associated microbiome dynamics
The feedback between selection and demography shapes genomic diversity during coevolution
Species interactions and coevolution are integral to ecological communities, but we lack empirical information on when and how these interactions generate and purge genetic diversity. Using genomic time series data from host-virus experiments, we found that coevolution occurs through consecutive selective sweeps in both species, with temporal consistency across replicates. Sweeps were accompanied by phenotypic change (resistance or infectivity increases) and expansions in population size. In the host, population expansion enabled rapid generation of genetic diversity in accordance with neutral processes. Viral molecular evolution was, in contrast, confined to few genes, all putative targets of selection. This study demonstrates that molecular evolution during species interactions is shaped by both eco-evolutionary feedback dynamics and interspecific differences in how genetic diversity is generated and maintained
A Visual Pathway Links Brain Structures Active during Magnetic Compass Orientation in Migratory Birds
The magnetic compass of migratory birds has been suggested to be light-dependent. Retinal cryptochrome-expressing neurons and a forebrain region, “Cluster N”, show high neuronal activity when night-migratory songbirds perform magnetic compass orientation. By combining neuronal tracing with behavioral experiments leading to sensory-driven gene expression of the neuronal activity marker ZENK during magnetic compass orientation, we demonstrate a functional neuronal connection between the retinal neurons and Cluster N via the visual thalamus. Thus, the two areas of the central nervous system being most active during magnetic compass orientation are part of an ascending visual processing stream, the thalamofugal pathway. Furthermore, Cluster N seems to be a specialized part of the visual wulst. These findings strongly support the hypothesis that migratory birds use their visual system to perceive the reference compass direction of the geomagnetic field and that migratory birds “see” the reference compass direction provided by the geomagnetic field
The role of emotions on consumers’ satisfaction within the fitness context
Previous studies have suggested that consumption-related emotions are important to understand post-purchase
reactions. This study examines the relationship between fitness consumers’ emotions and overall satisfaction. After an
initial step of free-thought listing and content validity, followed by a pre-test, a survey was conducted among consumers
of five different fitness centers (n=786). The questionnaire included measures to assess positive and negative emotions,
as well as overall satisfaction with the fitness center. The results gathered through a structural equation model provide
evidence that negative emotion experienced by consumers impacts negatively overall satisfaction, while positive emotion
have a positive effect on overall satisfaction. These findings suggest managerial implications, such as the need to collect
consumers’ perceptions of both tangible and intangible aspects of the services, listen costumers’ opinions in a regular
basis, and provide regular training to staff members, in order to identify the triggers of positive emotions and contribute
to increased levels of overall satisfaction. Guidelines for future research within the fitness context are also suggested.Estudos precedentes sugerem
que as emoções relacionadas com o consumo são importantes para compreender as reações dos consumidores após a
compra. Este estudo analisa a relação entre as emoções dos consumidores de fitness e satisfação global. Depois de uma
etapa inicial de listagem de pensamento-livre e validade de conteúdo, seguido de um pré-teste, foi realizada uma pesquisa
entre os consumidores de cinco centros de fitness diferentes (n = 786). O questionário incluiu medidas para avaliar as
emoções positivas e negativas, bem como a satisfação global com o centro de fitness. Os resultados obtidos através de
um modelo de equações estruturais forneceram evidências de que as emoções negativas vivenciadas pelos consumidores
impactam negativamente a satisfação global, enquanto as emoções positivas têm um efeito positivo sobre a satisfação
global. Estes resultados sugerem implicações para os gestores, tais como a necessidade de recolher informação sobre a
perceção dos consumidores dos aspetos tangíveis e intangíveis dos serviços, ouvir regularmente as opiniões dos consumidores
e facultar formação regular aos colaboradores. Isto permitirá identificar os aspetos que desencadeiam emoções
positivas e contribuir para o aumento dos níveis de satisfação global. Orientações para futuras pesquisas no contexto de
fitness também são sugeridas.Sin financiación0.185 SJR (2015) Q3, 1090/1779 Medicine (miscellaneous); Q4, 177/229 Health (social science), 112/128 Sports scienceUE
The management and outcome for patients with chronic subdural hematoma: a prospective, multicenter, observational cohort study in the United Kingdom
Symptomatic chronic subdural hematoma (CSDH) will become an increasingly common presentation in neurosurgical practice as the population ages, but quality evidence is still lacking to guide the optimal management for these patients. The British Neurosurgical Trainee Research Collaborative (BNTRC) was established by neurosurgical trainees in 2012 to improve research by combining the efforts of trainees in each of the United Kingdom (UK) and Ireland's neurosurgical units (NSUs). The authors present the first study by the BNTRC that describes current management and outcomes for patients with CSDH throughout the UK and Ireland. This provides a resource both for current clinical practice and future clinical research on CSDH
Fluoride concentrations in the pineal gland, brain and bone of goosander (Mergus merganser) and its prey in Odra River estuary in Poland
Pancreatic PYY but not PPY expression is responsive to short-term nutritional state and the pancreas constitutes the major site of PYY mRNA expression in chickens
Outcomes following surgery in subgroups of comatose and very elderly patients with chronic subdural hematoma
Increasing age and lower pre-operative Glasgow coma score (GCS) are associated with worse outcome after surgery for chronic subdural haematoma (CSDH). Only few studies have quantified outcomes specific to the very elderly or comatose patients. We aim to examine surgical outcomes in these patient groups. We analysed data from a prospective multicentre cohort study, assessing the risk of recurrence, death, and unfavourable functional outcome of very elderly (≥ 90 years) patients and comatose (pre-operative GCS ≤ 8) patients following surgical treatment of CSDH. Seven hundred eighty-five patients were included in the study. Thirty-two (4.1%) patients had pre-operative GCS ≤ 8 and 70 (8.9%) patients were aged ≥ 90 years. A higher proportion of comatose patients had an unfavourable functional outcome (38.7 vs 21.7%; p = 0.03), although similar proportion of comatose (64.5%) and non-comatose patients (61.8%) functionally improved after surgery (p = 0.96). Compared to patients aged < 90 years, a higher proportion of patients aged ≥ 90 years had unfavourable functional outcome (41.2 vs 20.5%; p < 0.01), although approximately half had functional improvement following surgery. Mortality risk was higher in both comatose (6.3 vs 1.9%; p = 0.05) and very elderly (8.8 vs 1.1%; p < 0.01) groups. There was a trend towards a higher recurrence risk in the comatose group (19.4 vs 9.5%; p = 0.07). Surgery can still provide considerable benefit to very elderly and comatose patients despite their higher risk of morbidity and mortality. Further research would be needed to better identify those most likely to benefit from surgery in these groups
A 1,000-loci transcript map of the barley genome: new anchoring points for integrative grass genomics
An integrated barley transcript map (consensus
map) comprising 1,032 expressed sequence tag
(EST)-based markers (total 1,055 loci: 607 RFLP, 190
SSR, and 258 SNP), and 200 anchor markers from previously
published data, has been generated by mapping
in three doubled haploid (DH) populations. Between
107 and 179 EST-based markers were allocated to the
seven individual barley linkage groups. The map covers
1118.3 cM with individual linkage groups ranging from
130 cM (chromosome 4H) to 199 cM (chromosome
3H), yielding an average marker interval distance of
0.9 cM. 475 EST-based markers showed a syntenic
organisation to known colinear linkage groups of the
rice genome, providing an extended insight into the
status of barley/rice genome colinearity as well as
ancient genome duplications predating the divergence
of rice and barley. The presented barley transcript map
is a valuable resource for targeted marker saturation
and identiWcation of candidate genes at agronomically
important loci. It provides new anchor points for
detailed studies in comparative grass genomics and will
support future attempts towards the integration of
genetic and physical mapping information
- …