1,091 research outputs found
Shimura varieties in the Torelli locus via Galois coverings of elliptic curves
We study Shimura subvarieties of obtained from families of
Galois coverings where is a smooth complex
projective curve of genus and . We give the complete list
of all such families that satisfy a simple sufficient condition that ensures
that the closure of the image of the family via the Torelli map yields a
Shimura subvariety of for and for all and
for and . In a previous work of the first and second author
together with A. Ghigi [FGP] similar computations were done in the case .
Here we find 6 families of Galois coverings, all with and
and we show that these are the only families with satisfying this
sufficient condition. We show that among these examples two families yield new
Shimura subvarieties of , while the other examples arise from
certain Shimura subvarieties of already obtained as families of
Galois coverings of in [FGP]. Finally we prove that if a family
satisfies this sufficient condition with , then .Comment: 18 pages, to appear in Geometriae Dedicat
Parabens as Urinary Biomarkers of Exposure in Humans
BACKGROUND: Parabens appear frequently as antimicrobial preservatives in cosmetic products, in pharmaceuticals, and in food and beverage processing. In vivo and in vitro studies have revealed weak estrogenic activity of some parabens. Widespread use has raised concerns about the potential human health risks associated with paraben exposure. OBJECTIVES: Assessing human exposure to parabens usually involves measuring in urine the conjugated or free species of parabens or their metabolites. In animals, parabens are mostly hydrolyzed to p-hydroxybenzoic acid and excreted in the urine as conjugates. Still, monitoring urinary concentrations of p-hydroxybenzoic acid is not necessarily the best way to assess exposure to parabens. p-Hydroxybenzoic acid is a nonspecific biomarker, and the varying estrogenic bioactivities of parabens require specific biomarkers. Therefore, we evaluated the use of free and conjugated parent parabens as new biomarkers for human exposure to these compounds. RESULTS: We measured the urinary concentrations of methyl, ethyl, n-propyl, butyl (n- and iso-), and benzyl parabens in a demographically diverse group of 100 anonymous adults. We detected methyl and n-propyl parabens at the highest median concentrations (43.9 ng/mL and 9.05 ng/mL, respectively) in nearly all (> 96%) of the samples. We also detected other parabens in more than half of the samples (ethyl, 58%; butyl, 69%). Most important, however, we found that parabens in urine appear predominantly in their conjugated forms. CONCLUSIONS: The results, demonstrating the presence of urinary conjugates of parabens in humans, suggest that such conjugated parabens could be used as exposure biomarkers. Additionally, the fact that conjugates appear to be the main urinary products of parabens may be important for risk assessment
The distribution of dark matter and gas spanning six megaparsecs around the post-merger galaxy cluster MS0451-03
Using the largest mosaic of Hubble Space Telescope images around a galaxy cluster, we map the distribution of dark matter throughout an ∼6 × 6 Mpc2 area centred on the cluster MS 0451−03 (z = 0.54, M200=1.65×1015M⊙). Our joint strong- and weak-lensing analysis shows three possible filaments extending from the cluster, encompassing six group-scale substructures. The dark matter distribution in the cluster core is elongated, consists of two distinct components, and is characterized by a concentration parameter of c200 = 3.79 ± 0.36. By contrast, XMM–Newton observations show the gas distribution to be more spherical, with excess entropy near the core, and a lower concentration of c200=2.35+0.89−0.70 (assuming hydrostatic equilibrium). Such a configuration is predicted in simulations of major mergers 2–7 Gyr after the first core passage, when the two dark matter haloes approach second turnaround, and before their gas has relaxed. This post-merger scenario finds further support in optical spectroscopy of the cluster’s member galaxies, which shows that star formation was abruptly quenched 5 Gyr ago. MS 0451−03 will be an ideal target for future studies of the growth of structure along filaments, star formation processes after a major merger, and the late-stage evolution of cluster collisions
Chronic widespread bodily pain is increased among individuals with history of fracture:findings from UK Biobank
Acknowledgments This work was supported by grants from the Medical Research Council, British Heart Foundation, Arthritis Research UK, National Osteoporosis Society, International Osteoporosis Foundation, NIHR Southampton Biomedical Research Centre, University of Southampton and University Hospital Southampton NHS Foundation Trust, and NIHR Musculoskeletal Biomedical Research Unit, University of Oxford. This research has been conducted using the UK Biobank Resource. Compliance with ethical standards.Peer reviewedPublisher PD
Utilizing individual fish biomass and relative abundance models to map environmental niche associations of adult and juvenile targeted fishes
Many fishes undergo ontogenetic habitat shifts to meet their energy and resource needs as they grow. Habitat resource partitioning and patterns of habitat connectivity between conspecific fishes at different life-history stages is a significant knowledge gap. Species distribution models were used to examine patterns in the relative abundance, individual biomass estimates and environmental niche associations of different life stages of three iconic West Australian fishes. Continuous predictive maps describing the spatial distribution of abundance and individual biomass of the study species were created as well predictive hotspot maps that identify possible areas for aggregation of individuals of similar life stages of multiple species (i.e. spawning grounds, fisheries refugia or nursery areas). The models and maps indicate that processes driving the abundance patterns could be different from the body size associated demographic processes throughout an individual's life cycle. Incorporating life-history in the spatially explicit management plans can ensure that critical habitat of the vulnerable stages (e.g. juvenile fish, spawning stock) is included within proposed protected areas and can enhance connectivity between various functional areas (e.g. nursery areas and adult populations) which, in turn, can improve the abundance of targeted species as well as other fish species relying on healthy ecosystem functioning
The long-run behaviour of the terms of trade between primary commodities and manufactures : a panel data approach
This paper examines the Prebisch and Singer hypothesis using a panel of twenty-four commodity prices from 1900 to 2010. The modelling approach stems from the need to meet two key concerns: (i) the presence of cross-sectional dependence among commodity prices; and (ii) the identification of potential structural breaks. To address these concerns, the Hadri and Rao (Oxf Bull Econ Stat 70:245–269, 2008) test is employed. The findings suggest that all commodity prices exhibit a structural break whose location differs across series, and that support for the Prebisch and Singer hypothesis is mixed. Once the breaks are removed from the underlying series, the persistence of commodity price shocks is shorter than that obtained in other studies using alternative methodologies.info:eu-repo/semantics/publishedVersio
Efficacy and safety of a subacromial continuous ropivacaine infusion for post-operative pain management following arthroscopic rotator cuff surgery: A protocol for a randomised double-blind placebo-controlled trial
<p>Abstract</p> <p>Background</p> <p>Major shoulder surgery often results in severe post-operative pain and a variety of interventions have been developed in an attempt to address this. The continuous slow infusion of a local anaesthetic directly into the operative site has recently gained popularity but it is expensive and as yet there is little conclusive evidence that it provides additional benefits over other methods of post-operative pain management.</p> <p>Methods/Design</p> <p>This will be a randomised, placebo-controlled trial involving 158 participants. Following diagnostic arthroscopy, all participants will undergo arthroscopic subacromial decompression with or without rotator cuff repair, all operations performed by a single surgeon. Participants, the surgeon, nurses caring for the patients and outcome assessors will be blinded to treatment allocation. All participants will receive a pre-incision bolus injection of 20 mls of ropivacaine 1% into the shoulder and an intra-operative intravenous bolus of parecoxib 40 mg. Using concealed allocation participants will be randomly assigned to active treatment (local anaesthetic ropivacaine 0.75%) or placebo (normal saline) administered continuously into the subacromial space by an elastomeric pump at 5 mls per hour post-operatively. Patient controlled opioid analgesia and oral analgesics will be available for breakthrough pain. Outcome assessment will be at 15, 30 and 60 minutes, 2, 4, 8, 12, 18 and 24 hours, and 2 or 4 months for decompression or decompression plus repair respectively.</p> <p>The primary end point will be average pain at rest over the first 12-hour post-operative period on a verbal analogue pain score. Secondary end points will be average pain at rest over the second 12-hour post-operative period, maximal pain at rest over the first and second 12-hour periods, amount of rescue medication used, length of inpatient stay and incidence of post-operative adhesive capsulitis.</p> <p>Discussion</p> <p>The results of this trial will contribute to evidence-based recommendations for the effectiveness of pain management modalities following arthroscopic rotator cuff surgery. If the local anaesthetic pain-buster provides no additional benefits over placebo then valuable resources can be put to better use in other ways.</p> <p>Trial registration</p> <p>Australian Clinical Trials Register Number ACTR12606000195550</p
An exploration of ambigrammatic sequences in narnaviruses
Narnaviruses have been described as positive-sense RNA viruses with a remarkably simple genome of ~3 kb, encoding only a highly conserved RNA-dependent RNA polymerase (RdRp). Many narnaviruses, however, are 'ambigrammatic' and harbour an additional uninterrupted open reading frame (ORF) covering almost the entire length of the reverse complement strand. No function has been described for this ORF, yet the absence of stops is conserved across diverse narnaviruses, and in every case the codons in the reverse ORF and the RdRp are aligned. The >3 kb ORF overlap on opposite strands, unprecedented among RNA viruses, motivates an exploration of the constraints imposed or alleviated by the codon alignment. Here, we show that only when the codon frames are aligned can all stop codons be eliminated from the reverse strand by synonymous single-nucleotide substitutions in the RdRp gene, suggesting a mechanism for de novo gene creation within a strongly conserved amino-acid sequence. It will be fascinating to explore what implications this coding strategy has for other aspects of narnavirus biology. Beyond narnaviruses, our rapidly expanding catalogue of viral diversity may yet reveal additional examples of this broadly-extensible principle for ambigrammatic-sequence development
Methods for specifying the target difference in a randomised controlled trial : the Difference ELicitation in TriAls (DELTA) systematic review
Peer reviewedPublisher PD
New Constraints (and Motivations) for Abelian Gauge Bosons in the MeV-TeV Mass Range
We survey the phenomenological constraints on abelian gauge bosons having
masses in the MeV to multi-GeV mass range (using precision electroweak
measurements, neutrino-electron and neutrino-nucleon scattering, electron and
muon anomalous magnetic moments, upsilon decay, beam dump experiments, atomic
parity violation, low-energy neutron scattering and primordial
nucleosynthesis). We compute their implications for the three parameters that
in general describe the low-energy properties of such bosons: their mass and
their two possible types of dimensionless couplings (direct couplings to
ordinary fermions and kinetic mixing with Standard Model hypercharge). We argue
that gauge bosons with very small couplings to ordinary fermions in this mass
range are natural in string compactifications and are likely to be generic in
theories for which the gravity scale is systematically smaller than the Planck
mass - such as in extra-dimensional models - because of the necessity to
suppress proton decay. Furthermore, because its couplings are weak, in the
low-energy theory relevant to experiments at and below TeV scales the charge
gauged by the new boson can appear to be broken, both by classical effects and
by anomalies. In particular, if the new gauge charge appears to be anomalous,
anomaly cancellation does not also require the introduction of new light
fermions in the low-energy theory. Furthermore, the charge can appear to be
conserved in the low-energy theory, despite the corresponding gauge boson
having a mass. Our results reduce to those of other authors in the special
cases where there is no kinetic mixing or there is no direct coupling to
ordinary fermions, such as for recently proposed dark-matter scenarios.Comment: 49 pages + appendix, 21 figures. This is the final version which
appears in JHE
- …