Regular spherical dust spacetimes

Physical (and weak) regularity conditions are used to determine and classify all the possible types of spherically symmetric dust spacetimes in general relativity. This work unifies and completes various earlier results. The junction conditions are described for general non-comoving (and non-null) surfaces, and the limits of kinematical quantities are given on all comoving surfaces where there is Darmois matching. We show that an inhomogeneous generalisation of the Kantowski-Sachs metric may be joined to the Lemaitre-Tolman-Bondi metric. All the possible spacetimes are explicitly divided into four groups according to topology, including a group in which the spatial sections have the topology of a 3-torus. The recollapse conjecture (for these spacetimes) follows naturally in this approach.Comment: Minor improvements, additional references. Accepted by GR

Smc5/6 coordinates formation and resolution of joint molecules with chromosome morphology to ensure meiotic divisions

During meiosis, Structural Maintenance of Chromosome (SMC) complexes underpin two fundamental features of meiosis: homologous recombination and chromosome segregation. While meiotic functions of the cohesin and condensin complexes have been delineated, the role of the third SMC complex, Smc5/6, remains enigmatic. Here we identify specific, essential meiotic functions for the Smc5/6 complex in homologous recombination and the regulation of cohesin. We show that Smc5/6 is enriched at centromeres and cohesin-association sites where it regulates sister-chromatid cohesion and the timely removal of cohesin from chromosomal arms, respectively. Smc5/6 also localizes to recombination hotspots, where it promotes normal formation and resolution of a subset of joint-molecule intermediates. In this regard, Smc5/6 functions independently of the major crossover pathway defined by the MutLγ complex. Furthermore, we show that Smc5/6 is required for stable chromosomal localization of the XPF-family endonuclease, Mus81-Mms4Eme1. Our data suggest that the Smc5/6 complex is required for specific recombination and chromosomal processes throughout meiosis and that in its absence, attempts at cell division with unresolved joint molecules and residual cohesin lead to severe recombination-induced meiotic catastroph

Clomifene citrate or low-dose FSH for the first-line treatment of infertile women with anovulation associated with polycystic ovary syndrome : a prospective randomized multinational study

BACKGROUND: Clomifene citrate (CC) is accepted as the first-line method for ovulation induction (OI) in patients with polycystic ovary syndrome (PCOS) associated with infertility owing to anovulation. Low-dose FSH has been reserved for women failing to conceive with CC. In this RCT, we tested the hypothesis that pregnancy rate (PR) and live birth rates (LBR) are higher after OI with low-dose FSH than with CC as first-line treatment. METHODS: Infertile women (<40 years old) with PCOS-related anovulation, without prior OI treatment, attending 10 centres in Europe/South America were randomized to OI with either CC (50-150 mg/day for 5 days) or FSH (starting dose 50 IU) for up to three treatment cycles. The primary outcome was clinical PR. RESULTS: Patients (n = 302) were randomized to OI with FSH (n = 132 women; 288 cycles) or CC (n = 123; 310 cycles). Per protocol analysis revealed that reproductive outcome was superior after OI with FSH than with CC with respect to PR per first cycle [30 versus 14.6%, respectively, 95 confidence interval (CI) 5.3-25.8, P = 0.003], PR per woman, (58 versus 44% of women, 95% CI 1.5-25.8, P = 0.03), LBR per woman (52 versus 39%, 95% CI 0.4-24.6, P = 0.04), cumulative PR (52.1 versus 41.2%, P = 0.021) and cumulative LBR (47.4 versus 36.9%, P = 0.031), within three cycles of OI. CONCLUSIONS: Pregnancies and live births are achieved more effectively and faster after OI with low-dose FSH than with CC. This result has to be balanced by convenience and cost in favour of CC. FSH may be an appropriate first-line treatment for some women with PCOS and anovulatory infertility, particularly older patients.peer-reviewe

Assessing the ecological risk posed by a recently established invasive alien predator: Harmonia axyridis as a case study

Invasive alien predators are a serious threat to biodiversity worldwide. However, there is no generic method for assessing which local species are most at risk following the invasion of a new predator. The harlequin ladybird, Harmonia axyridis (Pallas) (Coleoptera: Coccinellidae), is an alien in Europe and many other parts of the world where it affects other species of ladybirds through competition for food and intra-guild predation (IGP). Here, we describe a method developed to assess which European ladybird species are most at risk following the invasion of H. axyridis. The three components of the risk assessment are: the likelihood that the assessed native species encounters H. axyridis in the field, the hazard of competition for food, and the IGP hazard. Thirty native European ladybird species were assessed through data obtained from field observations, laboratory experiments and literature reviews. The species that are considered most at risk are found on deciduous trees, have immature stages which are highly vulnerable to IGP by H. axyridis, and are primarily aphidophagous. These species should be the focus of specific studies and possibly conservation actions. The risk assessment method proposed here could be applied to other alien predators which are considered a threat to native species through competition and predation

Effective Rheology of Bubbles Moving in a Capillary Tube

We calculate the average volumetric flux versus pressure drop of bubbles moving in a single capillary tube with varying diameter, finding a square-root relation from mapping the flow equations onto that of a driven overdamped pendulum. The calculation is based on a derivation of the equation of motion of a bubble train from considering the capillary forces and the entropy production associated with the viscous flow. We also calculate the configurational probability of the positions of the bubbles.Comment: 4 pages, 1 figur

Search for new phenomena in final states with an energetic jet and large missing transverse momentum in pp collisions at √ s = 8 TeV with the ATLAS detector

Results of a search for new phenomena in final states with an energetic jet and large missing transverse momentum are reported. The search uses 20.3 fb−1 of √ s = 8 TeV data collected in 2012 with the ATLAS detector at the LHC. Events are required to have at least one jet with pT > 120 GeV and no leptons. Nine signal regions are considered with increasing missing transverse momentum requirements between Emiss T > 150 GeV and Emiss T > 700 GeV. Good agreement is observed between the number of events in data and Standard Model expectations. The results are translated into exclusion limits on models with either large extra spatial dimensions, pair production of weakly interacting dark matter candidates, or production of very light gravitinos in a gauge-mediated supersymmetric model. In addition, limits on the production of an invisibly decaying Higgs-like boson leading to similar topologies in the final state are presente

Observation of the Baryonic Flavor-Changing Neutral Current Decay Lambda_b -> Lambda mu+ mu-

We report the first observation of the baryonic flavor-changing neutral current decay Lambda_b -> Lambda mu+ mu- with 24 signal events and a statistical significance of 5.8 Gaussian standard deviations. This measurement uses ppbar collisions data sample corresponding to 6.8fb-1 at sqrt{s}=1.96TeV collected by the CDF II detector at the Tevatron collider. The total and differential branching ratios for Lambda_b -> Lambda mu+ mu- are measured. We find B(Lambda_b -> Lambda mu+ mu-) = [1.73+-0.42(stat)+-0.55(syst)] x 10^{-6}. We also report the first measurement of the differential branching ratio of B_s -> phi mu+ mu- using 49 signal events. In addition, we report branching ratios for B+ -> K+ mu+ mu-, B0 -> K0 mu+ mu-, and B -> K*(892) mu+ mu- decays.Comment: 8 pages, 2 figures, 4 tables. Submitted to Phys. Rev. Let

The presentation, clinical features, complications, and treatment of congenital dacryocystocele

Purpose To determine the incidence and presenting features of congenital dacryocystocele in the United Kingdom. To report on those cases complicated by dacryocystitis, respiratory compromise, and the treatment undertaken. Methods A prospective observational study of cases of congenital dacryocystocele presenting in the United Kingdom between September 2014 and October 2015. Infants <3 months of age presenting with a cystic swelling in the medial canthal area were included. Cases were identified via the British Ophthalmology Surveillance Unit (BOSU) reporting system. Results A total of 49 cases were reported during the study period. This gives an incidence of 1 in 18 597 live births. There was a 71% response rate to the questionnaire. The average age at presentation was 16.94 days. Dacryocystoceles were unilateral in 91% of cases. Dacryocystitis was a complicating factor in 49% of patients and 17% had respiratory distress. Uncomplicated dacryocystocele responded well to conservative measures in 86%. Surgical intervention was required in 23% of patients. Those cases complicated by dacryocystitis (29%) and nasal obstruction (17%) were more likely to require surgical intervention compared to those with dacryocystocele alone (14%). Digital massage appears to reduce the likelihood of requiring surgical intervention. The mean time to resolution was 19 days. Conclusions Congenital dacryocystocele is a rare presentation in the United Kingdom. Dacryocystitis and respiratory compromise commonly complicate a dacryocystocele. The use of digital massage as an early intervention is advocated and conservative measures may be sufficient in cases of uncomplicated dacryocystocele

Relevance of large litter bag burial for the study of leaf breakdown in the hyporheic zone

Particulate organic matter is the major source of energy for most low-order streams, but a large part of this litter is buried within bed sediment during floods and thus become poorly available for benthic food webs. The fate of this buried litter is little studied. In most cases, measures of breakdown rates consist of burying a known mass of litter within the stream sediment and following its breakdown over time. We tested this method using large litter bags (15 x 15 cm) and two field experiments. First, we used litter large bags filled with Alnus glutinosa leaves (buried at 20 cm depth with a shovel) in six stations within different land-use contexts and with different sediment grain sizes. Breakdown rates were surprisingly high (0.0011–0.0188 day-1) and neither correlate with most of the physico-chemical characteristics measured in the interstitial habitats nor with the land-use around the stream. In contrast, the rates were negatively correlated with a decrease in oxygen concentrations between surface and buried bags and positively correlated with both the percentage of coarse particles (20–40 mm) in the sediment and benthic macro-invertebrate richness. These results suggest that the vertical exchanges with surface water in the hyporheic zone play a crucial role in litter breakdown. Second, an experimental modification of local sediment (removing fine particles with a shovel to increase vertical exchanges) highlighted the influence of grain size on water and oxygen exchanges, but had no effect on hyporheic breakdown rates. Burying large litter bags within sediments may thus not be a relevant method, especially in clogged conditions, due to changes induced through the burial process in the vertical connectivity between surface and interstitial habitats that modify organic matter processing

A xandarellid artiopodan from Morocco – a middle Cambrian link between soft-bodied euarthropod communities in North Africa and South China

NB. A corrigendum [correction] for this article was published online on 09 May 2017; this has been attached to this article as an additional file. This work is licensed under a Creative Commons Attribution 4.0 International License. The images or other third party material in this article are included in the article’s Creative Commons license, unless indicated otherwise in the credit line; if the material is not included under the Creative Commons license, users will need to obtain permission from the license holder to reproduce the material. To view a copy of this license, visit http://creativecommons.org/licenses/by/4.0/ © The Author(s) 2017. The attached file is the published version of the article