Trematode Infections inLittorina littoreaon the New Hampshire Coast

The prevalence of parasite infections in Littorina littorea (Common Periwinkle) was examined at 16 rocky intertidal sites along the New Hampshire coastline over three summers (2006 to 2008). We sampled over a relatively small spatial scale (21 km) and expected that the prevalence of infections in L. littorea would be similar between sites over this sampling area. In total, 1983 snails were collected from areas at mean low water during spring tides. Snail size (mm), gender, and type of parasitic infection were noted for all snails. Eleven percent of snails collected were infected with rediae and cercariae of the trematodes Cryptocotyle lingua or Cercaria parvicaudata; one snail had a double infection of both trematodes. The prevalence of infection at sites ranged from 1.9% to 30.1%. At all sites, female snails outnumbered male snails, and a greater proportion of females were infected than males. Large snails were more likely to be infected with trematodes at 3 sites, while a higher level of infection was found in small snails at 1 site. Snails at wave-protected sites were more likely to be infected than snails at wave-exposed sites. No relationship was found between the number of gulls at a site and the prevalence of infection. Although temporal variation in levels of prevalence in parasitic infections may explain some of our site-to-site differences, our data show large spatial variation of parasite prevalence in L. littorea over a minimum distance of 0.5 km and provide a foundation to test hypotheses concerning the susceptibility of female and immature (small) snails to infection

CCR5D32 mutation in three Brazilian populations of predominantly Sub-Saharan African ancestry

This study reports the frequencies of the CCR5D32 mutation of the beta-chemokine 5 gene and discusses the possible effects of past and recent gene flow in three quilombo remnants (Brazilians communities with anthropological African ancestry whose ancestors were escaped slaves): Rio das Rãs, Mocambo, and São Gonçalo in the northeastern region of Brazil. The CCR5D32 allele frequency of the Mocambo population was significantly higher (5.6%) than that found in the Rio das Rãs (1%) and São Gonçalo (0.9%) populations. These differences may reflect different proportions of parental populations in the founders individuals, a founder-effect and/or different histories of inter-ethnic contact. The frequency of the CCR5D32 allele in the Mocambo sample is similar to that found in those urban Brazilian populations which have a large amount of European genetic input, indicating a European contribution to the gene pool of this population and suggesting that, perhaps since its foundation, Mocambo has had a high level of admixture or experienced a founder-effect

Combination of searches for Higgs boson pairs in pp collisions at \sqrts = 13 TeV with the ATLAS detector

This letter presents a combination of searches for Higgs boson pair production using up to 36.1 fb(-1) of proton-proton collision data at a centre-of-mass energy root s = 13 TeV recorded with the ATLAS detector at the LHC. The combination is performed using six analyses searching for Higgs boson pairs decaying into the b (b) over barb (b) over bar, b (b) over barW(+)W(-), b (b) over bar tau(+)tau(-), W+W-W+W-, b (b) over bar gamma gamma and W+W-gamma gamma final states. Results are presented for non-resonant and resonant Higgs boson pair production modes. No statistically significant excess in data above the Standard Model predictions is found. The combined observed (expected) limit at 95% confidence level on the non-resonant Higgs boson pair production cross-section is 6.9 (10) times the predicted Standard Model cross-section. Limits are also set on the ratio (kappa(lambda)) of the Higgs boson self-coupling to its Standard Model value. This ratio is constrained at 95% confidence level in observation (expectation) to -5.0 &lt; kappa(lambda) &lt; 12.0 (-5.8 &lt; kappa(lambda) &lt; 12.0). In addition, limits are set on the production of narrow scalar resonances and spin-2 Kaluza-Klein Randall-Sundrum gravitons. Exclusion regions are also provided in the parameter space of the habemus Minimal Supersymmetric Standard Model and the Electroweak Singlet Model. For complete list of authors see http://dx.doi.org/10.1016/j.physletb.2019.135103</p

Searches for lepton-flavour-violating decays of the Higgs boson in s=13\sqrt{s}=13 TeV pp\mathit{pp} collisions with the ATLAS detector

This Letter presents direct searches for lepton flavour violation in Higgs boson decays, H → eτ and H → μτ , performed with the ATLAS detector at the LHC. The searches are based on a data sample of proton–proton collisions at a centre-of-mass energy √s = 13 TeV, corresponding to an integrated luminosity of 36.1 fb−1. No significant excess is observed above the expected background from Standard Model processes. The observed (median expected) 95% confidence-level upper limits on the leptonflavour-violating branching ratios are 0.47% (0.34+0.13−0.10%) and 0.28% (0.37+0.14−0.10%) for H → eτ and H → μτ , respectively.publishedVersio

Search for flavour-changing neutral currents in processes with one top quark and a photon using 81 fb⁻¹ of pp collisions at \sqrts = 13 TeV with the ATLAS experiment

A search for flavour-changing neutral current (FCNC) events via the coupling of a top quark, a photon, and an up or charm quark is presented using 81 fb−1 of proton–proton collision data taken at a centre-of-mass energy of 13 TeV with the ATLAS detector at the LHC. Events with a photon, an electron or muon, a b-tagged jet, and missing transverse momentum are selected. A neural network based on kinematic variables differentiates between events from signal and background processes. The data are consistent with the background-only hypothesis, and limits are set on the strength of the tqγ coupling in an effective field theory. These are also interpreted as 95% CL upper limits on the cross section for FCNC tγ production via a left-handed (right-handed) tuγ coupling of 36 fb (78 fb) and on the branching ratio for t→γu of 2.8×10−5 (6.1×10−5). In addition, they are interpreted as 95% CL upper limits on the cross section for FCNC tγ production via a left-handed (right-handed) tcγ coupling of 40 fb (33 fb) and on the branching ratio for t→γc of 22×10−5 (18×10−5). © 2019 The Author(s