475 research outputs found

    Assessing pollinators’ use of floral resource subsidies in agri-environment schemes: An illustration using Phacelia tanacetifolia and honeybees

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    Honeybees (Apis mellifera L.) are frequently used in agriculture for pollination services because of their abundance, generalist floral preferences, ease of management and hive transport. However, their populations are declining in many countries. Agri-Environment Schemes (AES) are being implemented in agricultural systems to combat the decline in populations of pollinators and other insects. Despite AES being increasingly embedded in policy and budgets, scientific assessments of many of these schemes still are lacking, and only a few studies have examined the extent to which insect pollinators use the floral enhancements that are part of AES and on which floral components they feed (i.e., pollen and/or nectar)

    Elastic Time Reversal Mirror Experiment in a Mesoscopic Natural Medium at the Low Noise Underground Laboratory of Rustrel, France

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    A seismic time reversal experiment based on Time Reversal Mirror (TRM) technique was conducted in the mesoscopically scaled medium at the LSBB Laboratory, France. Two sets of 50 Hz geophones were distributed at one meter intervals in two horizontal and parallel galleries 100 m apart, buried 250 m below the surface. The shot source used was a 4 kg sledgehammer. Analysis shows that elastic seismic energy is refocused in space and time to the shot locations with good accuracy. The refocusing ability of seismic energy to the shot locations is roughly achieved for the direct field, and with excellent quality, for the early and later coda. Hyper-focussing is achieved at the shot points as a consequence of the fine scale randomly heterogeneous medium between the galleries. TRM experiment is sensitive to the roughness of the mirror used. Roughness induces a slight experimental discrepancy between recording and re-emitting directions degrading the quality of the reversal process.Comment: 7 pages, 7 figures - This paper aimed at describing time reversal mirror method applied at mesoscopic scale to a natural medium in the frame of an active seismic experiment. The results confirm the hyper-focusing process in an anelastic medium and the efficiency of scattered waves within the coda to refocus at the source using the time reversal mirro

    The LF of TP-AGB stars in the LMC/SMC

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    We show that Monte Carlo simulations of the TP-AGB stellar population in the LMC and SMC galaxies using the CB. models produce LF and color distributions that are in closer agreement with observations than those obtained with the BC03 and CB07 models. This is a progress report of work that will be published elsewhere

    Assessing the invertebrate fauna trajectories in remediation sites of Winstone Aggregates Hunua quarry in Auckland

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    This study monitored the invertebrates in restoration plantings in the Winstone Aggregates Hunua Quarry. This was to assess the re-establishment of invertebrates in the restoration planting sites and compare them with unplanted control and mature sites. This study follows on from a baseline study carried out in 2014-2015 measuring the restoration trajectory of invertebrates in the Winstone Aggregate Hunua quarry site. A range of entomological monitoring techniques were used and found that dung beetles, millipedes, foliage moths, leaf litter moths and some mite species increased in numbers from the control sites through to the mature sites, while ants, rove beetles, grass moths, some carabid beetles, and worms showed a downwards trend from the mature sites to the control sites. Further monitoring of invertebrates in the restoration area should be carried out

    Responding positively to plant defences, a candidate key trait for invasion success in the New Zealand grass grub Costelytra zealandica

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    Occasionally, exotic plant introductions lead to the emergence of an invasive insect within its native geographical range. Such emergence could be explained by a pre-adaptation of the insect to break through the defences of the new encountered host. We investigated the fitness responses of two New Zealand endemic scarabs (Costelytra brunneum and C. zealandica ) when given a diet of an exotic pasture species, Trifolium repens, whose defences were artificially triggered by the phytohormone jasmonic acid. We found differential fitness responses between the two species when they were exposed to a defence-induced diet. We observed a significant weight increase in the invasive species C.zealandica when it was fed with treated roots compared with untreated controls, whereas no significant weight increase was observed in the non-invasive C.brunneum compared with the control treatments. Our study suggests that C. zealandica has a pre-existing ability to tolerate the defence chemicals of its exotic host and, more interestingly, to benefit from them, which may explain why this species has become a serious pest of pasture throughout its native geographical ran

    Spatial control of nucleoporin condensation by fragile X-related proteins

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    Nucleoporins (Nups) build highly organized nuclear pore complexes (NPCs) at the nuclear envelope (NE). Several Nups assemble into a sieve-like hydrogel within the central channel of the NPCs. In the cytoplasm, the soluble Nups exist, but how their assembly is restricted to the NE is currently unknown. Here, we show that fragile X-related protein 1 (FXR1) can interact with several Nups and facilitate their localization to the NE during interphase through a microtubule-dependent mechanism. Downregulation of FXR1 or closely related orthologs FXR2 and fragile X mental retardation protein (FMRP) leads to the accumulation of cytoplasmic Nup condensates. Likewise, models of fragile X syndrome (FXS), characterized by a loss of FMRP, accumulate Nup granules. The Nup granule-containing cells show defects in protein export, nuclear morphology and cell cycle progression. Our results reveal an unexpected role for the FXR protein family in the spatial regulation of nucleoporin condensation

    Specific shifts in the endocannabinoid system in hibernating brown bears

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    In small hibernators, global downregulation of the endocannabinoid system (ECS), which is involved in modulating neuronal signaling, feeding behavior, energy metabolism, and circannual rhythms, has been reported to possibly drive physiological adaptation to the hibernating state. In hibernating brown bears (Ursus arctos), we hypothesized that beyond an overall suppression of the ECS, seasonal shift in endocannabinoids compounds could be linked to bear's peculiar features that include hibernation without arousal episodes and capacity to react to external disturbance. We explored circulating lipids in serum and the ECS in plasma and metabolically active tissues in free-ranging subadult Scandinavian brown bears when both active and hibernating. In winter bear serum, in addition to a 2-fold increase in total fatty acid concentration, we found significant changes in relative proportions of circulating fatty acids, such as a 2-fold increase in docosahexaenoic acid C22:6 n-3 and a decrease in arachidonic acid C20:4 n-6. In adipose and muscle tissues of hibernating bears, we found significant lower concentrations of 2-arachidonoylglycerol (2-AG), a major ligand of cannabinoid receptors 1 (CB1) and 2 (CB2). Lower mRNA level for genes encoding CB1 and CB2 were also found in winter muscle and adipose tissue, respectively. The observed reduction in ECS tone may promote fatty acid mobilization from body fat stores, and favor carbohydrate metabolism in skeletal muscle of hibernating bears. Additionally, high circulating level of the endocannabinoid-like compound N-oleoylethanolamide (OEA) in winter could favor lipolysis and fatty acid oxidation in peripheral tissues. We also speculated on a role of OEA in the conservation of an anorexigenic signal and in the maintenance of torpor during hibernation, while sustaining the capacity of bears to sense stimuli from the environment

    Methods for the extraction, storage, amplification and sequencing of DNA from environmental samples

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    Advances in the sequencing of DNA extracted from media such as soil and water offer huge opportunities for biodiversity monitoring and assessment, particularly where the collection or identification of whole organisms is impractical. However, there are myriad methods for the extraction, storage, amplification and sequencing of DNA from environmental samples. To help overcome potential biases that may impede the effective comparison of biodiversity data collected by different researchers, we propose a standardised set of procedures for use on different taxa and sample media, largely based on recent trends in their use. Our recommendations describe important steps for sample pre-processing and include the use of (a) Qiagen DNeasy PowerSoil® and PowerMax® kits for extraction of DNA from soil, sediment, faeces and leaf litter; (b) DNeasy PowerSoil® for extraction of DNA from plant tissue; (c) DNeasy Blood and Tissue kits for extraction of DNA from animal tissue; (d) DNeasy Blood and Tissue kits for extraction of DNA from macroorganisms in water and ice; and (e) DNeasy PowerWater® kits for extraction of DNA from microorganisms in water and ice. Based on key parameters, including the specificity and inclusivity of the primers for the target sequence, we recommend the use of the following primer pairs to amplify DNA for analysis by Illumina MiSeq DNA sequencing: (a) 515f and 806RB to target bacterial 16S rRNA genes (including regions V3 and V4); (b) #3 and #5RC to target eukaryote 18S rRNA genes (including regions V7 and V8); (c) #3 and #5RC are also recommended for the routine analysis of protist community DNA; (d) ITS6F and ITS7R to target the chromistan ITS1 internal transcribed spacer region; (e) S2F and S3R to target the ITS2 internal transcribed spacer in terrestrial plants; (f) fITS7 or gITS7, and ITS4 to target the fungal ITS2 region; (g) NS31 and AML2 to target glomeromycota 18S rRNA genes; and (h) mICOIintF and jgHCO2198 to target cytochrome c oxidase subunit I (COI) genes in animals. More research is currently required to confirm primers suitable for the selective amplification of DNA from specific vertebrate taxa such as fish. Combined, these recommendations represent a framework for efficient, comprehensive and robust DNA-based investigations of biodiversity, applicable to most taxa and ecosystems. The adoption of standardised protocols for biodiversity assessment and monitoring using DNA extracted from environmental samples will enable more informative comparisons among datasets, generating significant benefits for ecological science and biosecurity applications

    0578: Valvular atrial fibrillation and the risk of stroke and deaths: additional prognostic value of the CHA2DS2-VASc score

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    PurposeThe CHA2DS2-VASc score has been validated and is widely used to stratify the risk of thromboembolism in patients with non-valvular atrial fibrillation (AF). We sought to investigate whether this score could also be useful to predict the risk of stroke and death in patients with valvular AF.MethodsBetween 1998 and 2011, 1,592 consecutive patients, hospitalised for AF, 300 with valvular AF (mitral and/or aortic valve disease) and 1,292 with non-valvular AF were enrolled in the cohort. All patients were followed-up at least 6 months and cardiovascular events recorded. The end-point was defined as the first occurrence of stroke or death. The Cox analysis was adjusted on warfarin, antiplatelet and antiarrhythmic treatments at discharge.ResultsMean age was 73±14 years in valvular AF and 68±15 in non-valvular AF (p=0.0001). At baseline, in the valvular AF group CHA2DS2-VASc score were = 0 for 14 (5%) patients, = 1 for 28 (9%), ? 2 for 258 (86%). Non-valvular AF CHA2DS2-VASc scores were = 0 for 158 (12%), = 1 for 189 (15), ?2 for 945 (73%). The difference was statistically significant (p<0.0001). During a mean follow-up of 4.6±3.5 years, the patients with valvular AF experienced 154 (51%) and the patients with non-valvular AF experienced 409 (32%) strokes or deaths. The Kaplan-Meier curves (figure) show that patients with a CHA2DS2-VASc score ?2 were at higher risk of stroke or death. The adjusted Cox model, showed that valvular AF (HR, 1.57, 95%CI 1.30-1.89, p<0.0001) and a CHA2DS2-VASc score ?2 (HR, 5.30, 95%CI 3.77-7.45, p<0.0001) were predictors of risk of stroke or death.ConclusionThese results suggest that a CHA2DS2-VASc score ?2 is associated with a higher risk of stroke and deaths, at mid-term follow-up, in patients with valvular AF (figure next page).Abstract 0578 - Figure: Kaplan-Meier survival curve

    Synergistic binding of transcription factors to cell-specific enhancers programs motor neuron identity

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    Efficient transcriptional programming promises to open new frontiers in regenerative medicine. However, mechanisms by which programming factors transform cell fate are unknown, preventing more rational selection of factors to generate desirable cell types. Three transcription factors, Ngn2, Isl1 and Lhx3, were sufficient to program rapidly and efficiently spinal motor neuron identity when expressed in differentiating mouse embryonic stem cells. Replacement of Lhx3 by Phox2a led to specification of cranial, rather than spinal, motor neurons. Chromatin immunoprecipitation–sequencing analysis of Isl1, Lhx3 and Phox2a binding sites revealed that the two cell fates were programmed by the recruitment of Isl1-Lhx3 and Isl1-Phox2a complexes to distinct genomic locations characterized by a unique grammar of homeodomain binding motifs. Our findings suggest that synergistic interactions among transcription factors determine the specificity of their recruitment to cell type–specific binding sites and illustrate how a single transcription factor can be repurposed to program different cell types.Project ALS FoundationNational Institutes of Health (U.S.) (Grant P01 NS055923
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