2,845 research outputs found
Global patterns of extinction risk and conservation needs for Rodentia and Eulipotyphla
AIM: To explore global patterns in spatial aggregations of species richness, vulnerability and data deficiency for Rodentia and Eulipotyphla. To evaluate the adequacy of existing protected area (PA) network for these areas. To provide a focus for local conservation initiatives. LOCATION: Global. METHODS: Total species, globally threatened (GT) species, and Data Deficient (DD) species richness were calculated for a 1° resolution grid. Correspondence analyses between global species richness against GT species richness were performed. To assess PA network adequacy, a correspondence analysis was conducted to identify areas of high richness and GT species richness that have poor protection. RESULTS: Six hotspots were identified for GT eulipotyphlans, encompassing 40% of GT species. Three of these contain higher numbers of GT species than would be expected based on their overall species richness. Ten priority regions were identified for GT rodents, which together contain 34% of all GT species. Six contain higher numbers of GT rodent species than would be expected based on their overall species richness. For DD species, 15% of DD eulipotyphlans were represented within three priority regions, whereas 18 were identified for rodents, capturing 53% of all DD species. Areas containing lower numbers of protected GT eulipotyphlan species than expected include Mexico; Cameroonian Highlands; Albertine Rift; Tanzania; Kenya; Ethiopia; western Asia; India; and Sri Lanka. Areas containing lower numbers of protected GT rodent species than expected are Borneo, Sumatra and Sulawesi. Five eulipotyphlans and 44 rodents have ranges which fall completely outside of PAs. MAIN CONCLUSION: Rodentia and Eulipotyphla priority regions should be considered separately to one another and to other mammals. This analysis approach allows us to pinpoint and delineate geographical areas which represent key regions at a global level for rodents and eulipotyphlans, in order to facilitate conservation, field research and capacity building at a local level
Sensory neuronal sensitisation occurs through HMGB-1/RAGE and TRPV1 in high glucose conditions
Many potential causes for painful diabetic neuropathy have been proposed including actions of cytokines and growth factors. High mobility group protein B1 (HMGB1) is a RAGE agonist, increased in diabetes, that contributes to pain by modulating peripheral inflammatory responses. HMGB1 enhances nociceptive behaviour in naïve animals through an unknown mechanism. We tested the hypothesis that HMGB1 causes pain through direct neuronal activation of RAGE and alteration of nociceptive neuronal responsiveness. HMGB1 and RAGE expression were increased in skin and primary sensory (DRG) neurons of diabetic rats at times when pain behaviour was enhanced. Agonist-evoked TRPV1-mediated calcium responses increased in cultured DRG neurons from diabetic rats and in neurons from naïve rats exposed to high glucose concentrations. HMGB1-mediated increases in TRPV1-evoked calcium responses in DRG neurons were RAGE and PKC-dependent, and this was blocked by co-administration of the growth factor splice variant, VEGF-A165b. Pain behaviour and DRG RAGE expression increases were blocked by VEGF-A 165 b treatment of diabetic rats in vivo. HMGB-1-RAGE activation sensitizes DRG neurons in vitro. VEGF-A165b blocks HMGB-1/RAGE DRG activation, which may contribute to its analgesic properties in vivo
Composition of piecewise pseudo almost periodic functions and applications to abstract impulsive differential equations
Galactic and Extragalactic Samples of Supernova Remnants: How They Are Identified and What They Tell Us
Supernova remnants (SNRs) arise from the interaction between the ejecta of a
supernova (SN) explosion and the surrounding circumstellar and interstellar
medium. Some SNRs, mostly nearby SNRs, can be studied in great detail. However,
to understand SNRs as a whole, large samples of SNRs must be assembled and
studied. Here, we describe the radio, optical, and X-ray techniques which have
been used to identify and characterize almost 300 Galactic SNRs and more than
1200 extragalactic SNRs. We then discuss which types of SNRs are being found
and which are not. We examine the degree to which the luminosity functions,
surface-brightness distributions and multi-wavelength comparisons of the
samples can be interpreted to determine the class properties of SNRs and
describe efforts to establish the type of SN explosion associated with a SNR.
We conclude that in order to better understand the class properties of SNRs, it
is more important to study (and obtain additional data on) the SNRs in galaxies
with extant samples at multiple wavelength bands than it is to obtain samples
of SNRs in other galaxiesComment: Final 2016 draft of a chapter in "Handbook of Supernovae" edited by
Athem W. Alsabti and Paul Murdin. Final version available at
https://doi.org/10.1007/978-3-319-20794-0_90-
A transient homotypic interaction model for the influenza A virus NS1 protein effector domain
Influenza A virus NS1 protein is a multifunctional virulence factor consisting of an RNA binding domain (RBD), a short linker, an effector domain (ED), and a C-terminal 'tail'. Although poorly understood, NS1 multimerization may autoregulate its actions. While RBD dimerization seems functionally conserved, two possible apo ED dimers have been proposed (helix-helix and strand-strand). Here, we analyze all available RBD, ED, and full-length NS1 structures, including four novel crystal structures obtained using EDs from divergent human and avian viruses, as well as two forms of a monomeric ED mutant. The data reveal the helix-helix interface as the only strictly conserved ED homodimeric contact. Furthermore, a mutant NS1 unable to form the helix-helix dimer is compromised in its ability to bind dsRNA efficiently, implying that ED multimerization influences RBD activity. Our bioinformatical work also suggests that the helix-helix interface is variable and transient, thereby allowing two ED monomers to twist relative to one another and possibly separate. In this regard, we found a mAb that recognizes NS1 via a residue completely buried within the ED helix-helix interface, and which may help highlight potential different conformational populations of NS1 (putatively termed 'helix-closed' and 'helix-open') in virus-infected cells. 'Helix-closed' conformations appear to enhance dsRNA binding, and 'helix-open' conformations allow otherwise inaccessible interactions with host factors. Our data support a new model of NS1 regulation in which the RBD remains dimeric throughout infection, while the ED switches between several quaternary states in order to expand its functional space. Such a concept may be applicable to other small multifunctional proteins
A study on the mutagenic effect of dichloromethane extract of pickled vegetables from high risk area for nasopharyngeal carcinoma (NPC)-in Sihui County
The mutagenic effect of dichloromethane extract of pickles collected from Sinhui County was examined. Sample I markedly increased the frequency of sister chromatid exchange (SCE) and the rate of micronucleus (MN) in mice. Sample II also induced an increase in SCE frequency significantly, but the increase in MN rate was slight. Chemical analyses showed that two samples of pickles contained 37.83ppb and 33.38ppb of volatile nitrosamines, respectively, which alone could not explain the observed mutagenic effect. These results sug ested that the pickled vegetables taken from NPC high-risk area, Sihui County, may contain some mutagen(s) besides volatile nitrosamines.
本文報告四會縣醃菜二氯甲烷提取液的誘變性試驗。醃菜樣本提取液Ⅰ號引起姐妹染色單體交換(SCE)率及微核(MN)率顯著升高,醃菜樣本提取液Ⅱ號亦引起SCE率明顯升高,但MN率僅略有升高。化學分析表明,該兩份醃菜的揮發性亞硝胺含量分別為37.83、33.38 ppb。醃菜提取液的誘變性似不能單用亞硝胺來解釋。實驗結果提示,鼻咽癌高發區四會縣醃菜中可能含有除揮發性亞硝胺以外的其他誘變性物質
Towards quantum computing with single atoms and optical cavities on atom chips
We report on recent developments in the integration of optical
microresonators into atom chips and describe some fabrication and
implementation challenges. We also review theoretical proposals for quantum
computing with single atoms based on the observation of photons leaking through
the cavity mirrors. The use of measurements to generate entanglement can result
in simpler, more robust and scalable quantum computing architectures. Indeed,
we show that quantum computing with atom-cavity systems is feasible even in the
presence of relatively large spontaneous decay rates and finite photon detector
efficiencies.Comment: 14 pages, 6 figure
Autism as a disorder of neural information processing: directions for research and targets for therapy
The broad variation in phenotypes and severities within autism spectrum disorders suggests the involvement of multiple predisposing factors, interacting in complex ways with normal developmental courses and gradients. Identification of these factors, and the common developmental path into which theyfeed, is hampered bythe large degrees of convergence from causal factors to altered brain development, and divergence from abnormal brain development into altered cognition and behaviour. Genetic, neurochemical, neuroimaging and behavioural findings on autism, as well as studies of normal development and of genetic syndromes that share symptoms with autism, offer hypotheses as to the nature of causal factors and their possible effects on the structure and dynamics of neural systems. Such alterations in neural properties may in turn perturb activity-dependent development, giving rise to a complex behavioural syndrome many steps removed from the root causes. Animal models based on genetic, neurochemical, neurophysiological, and behavioural manipulations offer the possibility of exploring these developmental processes in detail, as do human studies addressing endophenotypes beyond the diagnosis itself
AB-QTL analysis in winter wheat: II. Genetic analysis of seedling and field resistance against leaf rust in a wheat advanced backcross population
The present study aimed to localize exotic quantitative trait locus (QTL) alleles for the improvement of leaf rust (P.triticina) resistance in an advanced backcross (AB) population, B22, which is derived from a cross between the winter wheat cultivar Batis (Triticumaestivum) and the synthetic wheat accession Syn022L. The latter was developed from hybridization of T.turgidum ssp. dicoccoides and T.tauschii. Altogether, 250 BC2F3 lines of B22 were assessed for seedling resistance against the leaf rust isolate 77WxR under controlled conditions. In addition, field resistance against leaf rust was evaluated by assessing symptom severity under natural infestation across multiple environments. Simultaneously, population B22 was genotyped with a total of 97 SSR markers, distributed over the wheat A, B and D genomes. The phenotype and genotype data were subjected to QTL analysis by applying a 3-factorial mixed model analysis of variance including the marker genotype as a fixed effect and the environments, the lines and the marker by environment interactions as random effects. The QTL analysis revealed six putative QTLs for seedling resistance and seven for field resistance. For seedling resistance, the effects of exotic QTL alleles improved resistance at all detected loci. The maximum decrease of disease symptoms (−46.3%) was associated with marker locus Xbarc149 on chromosome 1D. For field resistance, two loci had stable main effects across environments and five loci exhibited marker by environment interaction effects. The strongest effects were detected at marker locus Xbarc149 on chromosome 1D, at which the exotic allele decreased seedling symptoms by 46.3% and field symptoms by 43.6%, respectively. Some of the detected QTLs co-localized with known resistance genes, while others appear to be as novel resistance loci. Our findings indicate, that the exotic wheat accession Syn022L may be useful for the improvement of leaf rust resistance in cultivated wheat
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