408 research outputs found
Eradication of invasive birds from tropical oceanic islands: lessons learned from studies of common mynas Acridotheres tristis
Feare, C., Greenwell, P., Edwards, H., Taylor, J., Van der Woude, J
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Predicting resilience of ecosystem functioning from co‐varying species' responses to environmental change
Understanding how environmental change affects ecosystem function delivery is of primary importance for fundamental and applied ecology. Current approaches focus on single environmental driver effects on communities, mediated by individual response traits. Data limitations present constraints in scaling up this approach to predict the impacts of multivariate environmental change on ecosystem functioning.
We present a more holistic approach to determine ecosystem function resilience, using long‐term monitoring data to analyze the aggregate impact of multiple historic environmental drivers on species' population dynamics. By assessing covariation in population dynamics between pairs of species, we identify which species respond most synchronously to environmental change and allocate species into “response guilds.” We then use “production functions” combining trait data to estimate the relative roles of species to ecosystem functions. We quantify the correlation between response guilds and production functions, assessing the resilience of ecosystem functioning to environmental change, with asynchronous dynamics of species in the same functional guild expected to lead to more stable ecosystem functioning.
Testing this method using data for butterflies collected over four decades in the United Kingdom, we find three ecosystem functions (resource provisioning, wildflower pollination, and aesthetic cultural value) appear relatively robust, with functionally important species dispersed across response guilds, suggesting more stable ecosystem functioning. Additionally, by relating genetic distances to response guilds we assess the heritability of responses to environmental change. Our results suggest it may be feasible to infer population responses of butterflies to environmental change based on phylogeny—a useful insight for conservation management of rare species with limited population monitoring data.
Our approach holds promise for overcoming the impasse in predicting the responses of ecosystem functions to environmental change. Quantifying co‐varying species' responses to multivariate environmental change should enable us to significantly advance our predictions of ecosystem function resilience and enable proactive ecosystem management
Economics of Field Pea Supplementation for Cattle Grazing Crested Wheatgrass
Heifers grazing crested wheat grass were supplemented either field peas or dried distillers grains plus solubles (DDGS) at 0.4% or 0.8% of body weight. Heifers supplemented with field peas had 10% lower daily gain compared to their DDGS supplemented counterparts. The decision to supplement field peas for producers depends on the price at which field peas can be acquired, as well as the distance that DDGS has to be hauled in order to be utilized. Field peas are a viable option in western Nebraska as a supplement for grazing cattle when DDGS is unavailable or field peas are in excess and can be obtained below the human consumption and pet food market price
Triplet repeats form secondary structures that escape DNA repair in yeast
Several human neurodegenerative diseases result from expansion of CTG/CAG or CGG/CCG triplet repeats. The finding that single-stranded CNG repeats form hairpin-like structures in vitro has led to the hypothesis that DNA secondary structure formation is an important component of the expansion mechanism. We show that single-stranded DNA loops containing 10 CTG/CAG or CGG/CCG repeats are inefficiently repaired during meiotic recombination in Saccharomyces cerevisiae. Comparisons of the repair of DNA loops with palindromic and nonpalindromic sequences suggest that this inefficient repair reflects the ability of these sequences to form hairpin structures in vivo
Fluorescence in-situ hybridisation on biopsies from clam ileocystoplasties and on a clam cancer
The incidence of carcinoma following an enterocystoplasty increases with time and is a major concern after such procedures. The aim of this study was to investigate genetic instability (in the form of numerical chromosomal aberrations) at the enterovesical anastomosis in patients who had undergone a clam ileocystoplasty using fluorescent in-situ hybridisation (FISH). Fluorescent in-situ hybridisation was performed on touch preparation samples prepared from fresh endoscopic biopsies obtained from the enterovesical anastomosis and native bladder remnant (control specimens) of 15 patients who had undergone a clam ileocystoplasty. Fluorescent in-situ hybridisation was also performed on one squamous cell cancer specimen. Significant aneusomic changes were found at the enterovesical anastomosis in all 15 patients. Alterations in chromosome 18 copy number were the most frequent abnormal finding (trisomy 18, n=8; monosomy 18, n=7). Nine patients were monosomic for chromosome 9. Isolated monosomy 8 and trisomy 8 were each found in one patient. The control specimens were all normal. An unusually high incidence of polysomic cells was found in the clam tumour specimen, reflecting the aggressive nature of this cancer. Chromosomal numerical abnormalities occur at the enterovesical anastomosis following a clam ileocystoplasty and chromosome 18 appears to be a particularly good marker of genetic instability. The results of this study indicate that morphologically normal tissue obtained from the enterovesical anastomosis displays evidence of chromosomal instability that may predispose to tumour formation. However, further prospective, blinded, longitudinal studies are required to establish whether predetermined FISH signal patterns in enterocystoplasty cells in urine or obtained by biopsy predict the presence or absence of tumour
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The influence of chalk grasslands on butterfly phenology and ecology
The influence of large-scale variables such as climate change on phenology has received a great deal of research attention. However, local environmental factors also play a key role in determining the timing of species life cycles. Using the meadow brown butterfly Maniola jurtina as an example, we investigate how a specific habitat type, lowland calcareous grassland, can affect the timing of flight dates. Although protracted flight periods have previously been reported in populations on chalk grassland sites in the south of England, no attempt has yet been made to quantify this at a national level, or to assess links with population genetics and drought tolerance. Using data from 539 sites across the UK, these differences in phenology are quantified, and M. jurtina phenology is found to be strongly associated with both site geology and topography, independent of levels of abundance. Further investigation into aspects of M. jurtina ecology at a subset of sites finds no genetic structuring or drought tolerance associated with these same site conditions
Gene Copy-Number Variation in Haploid and Diploid Strains of the Yeast Saccharomyces cerevisiae
The increasing ability to sequence and compare multiple individual genomes within a species has highlighted the fact that copy-number variation (CNV) is a substantial and underappreciated source of genetic diversity. Chromosome-scale mutations occur at rates orders of magnitude higher than base substitutions, yet our understanding of the mechanisms leading to CNVs has been lagging. We examined CNV in a region of chromosome 5 (chr5) in haploid and diploid strains of Saccharomyces cerevisiae. We optimized a CNV detection assay based on a reporter cassette containing the SFA1 and CUP1 genes that confer gene dosage-dependent tolerance to formaldehyde and copper, respectively. This optimized reporter allowed the selection of low-order gene amplification events, going from one copy to two copies in haploids and from two to three copies in diploids. In haploid strains, most events involved tandem segmental duplications mediated by nonallelic homologous recombination between flanking direct repeats, primarily Ty1 elements. In diploids, most events involved the formation of a recurrent nonreciprocal translocation between a chr5 Ty1 element and another Ty1 repeat on chr13. In addition to amplification events, a subset of clones displaying elevated resistance to formaldehyde had point mutations within the SFA1 coding sequence. These mutations were all dominant and are proposed to result in hyperactive forms of the formaldehyde dehydrogenase enzyme
An examination of intentions of recommending fitness centers by user members
The goal of this study was to examine what experiences members have with fitness centers that influence
their intentions for recommendation. After item generation and content validity, as well as a pilot test, a survey was
conducted among members of five different clubs (n=1750). The questionnaire included measures of service quality
attributes, accessibility, well-being in life, well-being in a club, and intentions to recommend a fitness center. Results
using a structural equation model provide evidence that only service quality attributes and well-being in a club have
positive effect on intentions of users to recommend it. Well-being in life has a negative effect on the intentions for recommendation,
while accessibility shows no predictive effect. These findings suggest implications for the management
of a club, such as the need to create a pleasant environment and to provide a personalized service directed towards the
members’ goals in order to improve well-being in a club and contribute to increase the intentions to recommend the
fitness centers to others.O objetivo
deste estudo foi examinar como as experiências de usuários de centros de atividade física interferem nas intenções em
recomendar serviços. Depois de gerar itens e validar o conteúdo, aplicou-se um pré-teste, o questionário final foi aplicado
a sócios de cinco clubes de fitness (n=1.750). O questionário incluiu atributos da qualidade do serviço, acessibilidade,
bem-estar na vida, bem-estar no clube e intenção de recomendar. O modelo de equações estruturais mostrou que apenas
os atributos da qualidade do serviço e bem-estar no clube têm um efeito positivo sobre as intenções de recomendar.
O bem-estar na vida tem um efeito negativo sobre as intenções para recomendar, enquanto que a acessibilidade não
mostra nenhum efeito preditivo. Estas conclusões sugerem a necessidade de criar um ambiente agradável nos clubes e
de oferecer um serviço personalizado para os objetivos dos sócios, a fim de melhorar o bem-estar no clube e contribuir
para a intenção de recomendar o ginásio.
Palavras-chave: intenção de recomendar, atributos da qualSin financiación0.191 SJR (2014) Q3, posición 172/231 Health (social science), 1027/1811 Medicine (miscellaneous); Q4, 112/128 Sports scienceUE
Progressive Rearrangement of Telomeric Sequences Added to Both the ITR Ends of the Yeast Linear pGKL Plasmid
Relocation into the nucleus of the yeast cytoplasmic linear plasmids was studied using a monitor plasmid pCLU1. In Saccharomyces cerevisiae, the nuclearly-relocated pCLU1 replicated in a linear form (termed pTLU-type plasmid) which carried the host telomeric repeats TG(1-3) of 300-350 bp at both ends. The telomere sequences mainly consisted of a major motif TGTGTGGGTGTGG which was complementary to part of the RNA template of yeast telomerase and were directly added to the very end of the pCLU1-terminal element ITR (inverted terminal repeat), suggesting that the ITR end played a role as a substrate of telomerase. The telomere sequences varied among isolated pTLU-type plasmids, but the TG(1-3) organization was symmetrically identical on both ends of any one plasmid. During cell growth under non-selective condition, the telomeric repeat sequences were progressively rearranged on one side, but not on the opposite side of pTLU plasmid ends. This indicates that the mode of telomeric DNA replication or repair differed between both ends. Clonal analysis showed that the intense rearrangement of telomeric DNA was closely associated with extreme instability of pTLU plasmids
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A safe and just operating space for human identity: a systems perspective
A safe and just operating space for socioecological systems is a powerful bridging concept in sustainability science. It integrates biophysical earth-system tipping points (ie, thresholds at which small changes can lead to amplifying effects) with social science considerations of distributional equity and justice. Often neglected, however, are the multiple feedback loops between self-identity and planetary boundaries. Environmental degradation can reduce self-identification with nature, leading to decreased pro-environmental behaviours and decreased cooperation with out-groups, further increasing the likelihood of transgressing planetary boundaries. This vicious cycle competes with a virtuous one, where improving environmental quality enhances the integration of nature into self-identity and improves health, thereby facilitating prosocial and pro-environmental behaviour. These behavioural changes can also cascade up to influence social and economic institutions. Given a possible minimum degree of individual self-care to maintain health and prosperity, there would seem to exist an analogous safe and just operating space for self-identity, for which system stewardship for planetary health is crucial
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