pinecone/core-2020-05-10-deduplication huggingface dataset:
Abyssal hills – hidden source of increased habitat heterogeneity, benthic megafaunal biomass and diversity in the deep sea

AbstractAbyssal hills are the most abundant landform on Earth, yet the ecological impact of the resulting habitat heterogeneity on the wider abyss is largely unexplored. Topographic features are known to influence food availability and the sedimentary environment in other deep-sea habitats, in turn affecting the species assemblage and biomass. To assess this spatial variation, benthic assemblages and environmental conditions were compared at four hill and four plain sites at the Porcupine Abyssal Plain. Here we show that differences in megabenthic communities on abyssal hills and the adjacent plain are related to environmental conditions, which may be caused by local topography and hydrodynamics. Although these hills may receive similar particulate organic carbon flux (food supply from the surface ocean) to the adjacent plain, they differ significantly in depth, slope, and sediment particle size distribution. We found that megafaunal biomass was significantly greater on the hills (mean 13.45gm−2, 95% confidence interval 9.25–19.36gm−2) than the plain (4.34gm−2, 95% CI 2.08–8.27gm−2; ANOVA F(1,6)=23.8, p<0.01). Assemblage and trophic compositions by both density and biomass measures were significantly different between the hill and plain, and correlated with sediment particle size distributions. Hydrodynamic conditions responsible for the local sedimentary environment may be the mechanism driving these assemblage differences. Since the ecological heterogeneity provided by hills in the abyss has been underappreciated, regional assessments of abyssal biological heterogeneity and diversity may be considerably higher than previously thought
Distinct Conformations of Ly49 Natural Killer Cell Receptors Mediate MHC Class I Recognition in Trans and Cis

SummaryCertain cell-surface receptors engage ligands expressed on juxtaposed cells and ligands on the same cell. The structural basis for trans versus cis binding is not known. Here, we showed that Ly49 natural killer (NK) cell receptors bound two MHC class I (MHC-I) molecules in trans when the two ligand-binding domains were backfolded onto the long stalk region. In contrast, dissociation of the ligand-binding domains from the stalk and their reorientation relative to the NK cell membrane allowed monovalent binding of MHC-I in cis. The distinct conformations (backfolded and extended) define the structural basis for cis-trans binding by Ly49 receptors and explain the divergent functional consequences of cis versus trans interactions. Further analyses identified specific stalk segments that were not required for MHC-I binding in trans but were essential for inhibitory receptor function. These data identify multiple distinct roles of stalk regions for receptor function
Maritime shipping and emissions: A three-layered, damage-based approach

AbstractPolicy emphasis in ship design must be shifted away from global and idealized towards regional based and realistic vessel operating conditions. The present approach to reducing shipping emissions through technical standards tends to neglect how damages and abatement opportunities vary according to location and operational conditions. Since environmental policy originates in damages relating to ecosystems and jurisdictions, a three-layered approach to vessel emissions is intuitive and practical. Here, we suggest associating damages and policies with ports, coastal areas possibly defined as Emission Control Areas (ECA) as in the North Sea and the Baltic, and open seas globally. This approach offers important practical opportunities: in ports, clean fuels or even electrification is possible; in ECAs, cleaner fuels and penalties for damaging fuels are important, but so is vessel handling, such as speeds and utilization. Globally we argue that it may be desirable to allow burning very dirty fuels at high seas, due to the cost advantages, the climate cooling benefits, and the limited ecosystem impacts. We quantify the benefits and cost savings from reforming current IMO and other approaches towards environmental management with a three-layered approach, and argue it is feasible and worth considering
Single transverse-spin asymmetry in semi-inclusive deep inelastic scattering

AbstractWe study the single transverse-spin asymmetry in semi-inclusive hadron production in deep inelastic scattering. We derive the leading contribution to the asymmetry at moderate transverse momentum Ph⊥ of the produced hadron in terms of twist-three quark–gluon correlation functions, and compare with the result obtained from the approach based on factorization at fixed transverse momentum which involves asymmetric transverse-momentum and spin-dependent quark distributions. We verify that the two approaches yield identical results in this regime. Comparing with our earlier calculations for the single-spin asymmetry in the Drell–Yan process, we confirm the sign difference between the time-reversal-odd transverse-momentum-dependent quark distributions in the two processes
Topological structure of direct limits in the category of uniform spaces

AbstractLet (Xn)n∈ω be a sequence of uniform spaces such that each space Xn is a subspace in Xn+1. We give an explicit description of the topology and uniformity of the direct limit u-lim→Xn of the sequence (Xn) in the category of uniform spaces. This description implies that a function f:u-lim→Xn→Y to a uniform space Y is continuous if for every n∈N the restriction f|Xn is continuous and regular at the subset Xn−1 in the sense that for any entourages U∈UY and V∈UX there is an entourage W∈UX such that for each point x∈B(Xn−1,W) there is a point x′∈Xn−1 with (x,x′)∈V and (f(x),f(x′))∈U. Also we shall compare topologies of direct limits in various categories
Retreat history of the East Antarctic Ice Sheet since the Last Glacial Maximum

AbstractThe East Antarctic Ice Sheet (EAIS) is the largest continental ice mass on Earth, and documenting its evolution since the Last Glacial Maximum (LGM) is important for understanding its present-day and future behaviour. As part of a community effort, we review geological evidence from East Antarctica that constrains the ice sheet history throughout this period (∼30,000 years ago to present). This includes terrestrial cosmogenic nuclide dates from previously glaciated regions, 14C chronologies from glacial and post-glacial deposits onshore and on the continental shelf, and ice sheet thickness changes inferred from ice cores and continental-scale ice sheet models. We also include new 14C dates from the George V Land – Terre Adélie Coast shelf. We show that the EAIS advanced to the continental shelf margin in some parts of East Antarctica, and that the ice sheet characteristically thickened by 300–400 m near the present-day coastline at these sites. This advance was associated with the formation of low-gradient ice streams that grounded at depths of >1 km below sea level on the inner continental shelf. The Lambert/Amery system thickened by a greater amount (800 m) near its present-day grounding zone, but did not advance beyond the inner continental shelf. At other sites in coastal East Antarctica (e.g. Bunger Hills, Larsemann Hills), very little change in the ice sheet margin occurred at the LGM, perhaps because ice streams accommodated any excess ice build up, leaving adjacent, ice-free areas relatively unaffected. Evidence from nunataks indicates that the amount of ice sheet thickening diminished inland at the LGM, an observation supported by ice cores, which suggest that interior ice sheet domes were ∼100 m lower than present at this time. Ice sheet recession may have started ∼18,000 years ago in the Lambert/Amery glacial system, and by ∼14,000 years ago in Mac.Robertson Land. These early pulses of deglaciation may have been responses to abrupt sea-level rise events such as Meltwater Pulse 1a, destabilising the margins of the ice sheet. It is unlikely, however, that East Antarctica contributed more than ∼1 m of eustatic sea-level equivalent to post-glacial meltwater pulses. The majority of ice sheet recession occurred after Meltwater Pulse 1a, between ∼12,000 and ∼6000 years ago, during a period when the adjacent ocean warmed significantly. Large tracts of East Antarctica remain poorly studied, and further work is required to develop a robust understanding of the LGM ice sheet expansion, and its subsequent contraction. Further work will also allow the contribution of the EAIS to post-glacial sea-level rise, and present-day estimates of glacio-isostatic adjustment to be refined
New Interaction Paradigms to Fight the Digital Divide: A Pilot Case Study Regarding Multi-Touch Technology

AbstractInformation and Communication Technologies (ICTs) are considered a powerful tool for economic development and the growth of societies. However, instead of helping overcome society's inequalities caused by the digital era, they have instigated an increase of the people that rested aside of the information age. The digital divide refers to the difficulty info- excluded people have in keeping up with technological advances. This phenomenon was triggered by the rapid growth and dissemination of technological equipment, as a portion of society did not have the proper time or knowledge to adjust. This paper sets forth a new approach to help fight the Portuguese digital divide by presenting new ways of interaction. Resorting to multi-touch technology, we examine how this new natural interaction paradigm can have a positive influence in the struggle against info-exclusion. For this purpose, we present a multi-touch game envisioned to encourage and teach digitally excluded people on how to use an important and needed everyday equipment – the ATM (Automated Teller Machine) – as it is still avoided by some. We believe that our pilot case study can show preliminary results on how natural user interfaces may be beneficial to help overcome some difficulties enforced by the digital divide. We consider that our findings may be valuable to show a possible path of how the new natural user interfaces can help bring technology and people closer. After being asked about their user experience, the participants of this exploratory study agreed that the game encouraged them to explore more about new technologies
Continuous crystal and Duistermaat–Heckman measure for Coxeter groups

AbstractWe introduce a notion of continuous crystal analogous, for general Coxeter groups, to the combinatorial crystals introduced by Kashiwara in representation theory of Lie algebras. We explore their main properties in the case of finite Coxeter groups, where we use a generalization of the Littelmann path model to show the existence of the crystals. We introduce a remarkable measure, analogous to the Duistermaat–Heckman measure, which we interpret in terms of Brownian motion. We also show that the Littelmann path operators can be derived from simple considerations on Sturm–Liouville equations
Involvement of Mitochondrial Ferredoxin and Para-Aminobenzoic Acid in Yeast Coenzyme Q Biosynthesis

SummaryYeast ubiquinone or coenzyme Q6 (Q6) is a redox active lipid that plays a crucial role in the mitochondrial electron transport chain. At least nine proteins (Coq1p–9p) participate in Q6 biosynthesis from 4-hydroxybenzoate (4-HB). We now show that the mitochondrial ferredoxin Yah1p and the ferredoxin reductase Arh1p are required for Q6 biosynthesis, probably for the first hydroxylation of the pathway. Conditional Gal-YAH1 and Gal-ARH1 mutants accumulate 3-hexaprenyl-4-hydroxyphenol and 3-hexaprenyl-4-aminophenol. Para-aminobenzoic acid (pABA) is shown to be the precursor of 3-hexaprenyl-4-aminophenol and to compete with 4-HB for the prenylation reaction catalyzed by Coq2p. Yeast cells convert U-(13C)-pABA into 13C ring-labeled Q6, a result that identifies pABA as a new precursor of Q6 and implies an additional NH2-to-OH conversion in Q6 biosynthesis. Our study identifies pABA, Yah1p, and Arh1p as three actors in Q6 biosynthesis
Oculomotor preparation as a rehearsal mechanism in spatial working memory

AbstractThere is little consensus regarding the specific processes responsible for encoding, maintenance, and retrieval of information in visuo-spatial working memory (VSWM). One influential theory is that VSWM may involve activation of the eye-movement (oculomotor) system. In this study we experimentally prevented healthy participants from planning or executing saccadic eye-movements during the encoding, maintenance, and retrieval stages of visual and spatial working memory tasks. Participants experienced a significant reduction in spatial memory span only when oculomotor preparation was prevented during encoding or maintenance. In contrast there was no reduction when oculomotor preparation was prevented only during retrieval. These results show that (a) involvement of the oculomotor system is necessary for optimal maintenance of directly-indicated locations in spatial working memory and (b) oculomotor preparation is not necessary during retrieval from spatial working memory. We propose that this study is the first to unambiguously demonstrate that the oculomotor system contributes to the maintenance of spatial locations in working memory independently from the involvement of covert attention
Generators, relations and symmetries in pairs of 3×3 unimodular matrices

AbstractDenote the free group on two letters by F2 and the SL(3,C)-representation variety of F2 by R=Hom(F2,SL(3,C)). There is a SL(3,C)-action on the coordinate ring of R, and the geometric points of the subring of invariants is an affine variety X. We determine explicit minimal generators and defining relations for the subring of invariants and show X is a degree 6 hyper-surface in C9 mapping onto C8. Our choice of generators exhibit Out(F2) symmetries which allow for a succinct expression of the defining relations
A Monte Carlo study of erraticity behavior in nucleus–nucleus collisions at high energies

AbstractIt is demonstrated using Monte Carlo simulation that in different nucleus–nucleus collision samples, the increase of the fluctuation of event factorial moments with decreasing phase space scale, called erraticity, is still dominated by the statistical fluctuations. This result does not depend on the Monte Carlo models. Nor does it depend on the concrete conditions, e.g., the collision energy, the mass of colliding nuclei, the cut of phase space, etc. This means that the erraticity method is sensitive to the appearance of novel physics in the central collisions of heavy nuclei
The B→K⁎ form factors on the lattice

AbstractThe extraction of the B→K⁎ transition form factors from lattice data is studied, applying non-relativistic effective field theory in a finite volume. The possible mixing of πK and ηK states is taken into account. The two-channel analogue of the Lellouch–Lüscher formula is reproduced. Due to the resonance nature of the K⁎, an equation is derived, which allows to determine the form factors at the pole position in a process-independent manner. The infinitely-narrow width approximation of the results is discussed
Search for direct slepton and gaugino production in final states with two leptons and missing transverse momentum with the ATLAS detector in pp collisions at s=7 TeV

AbstractA search for the electroweak pair production of charged sleptons and weak gauginos decaying into final states with two leptons is performed using 4.7 fb−1 of proton–proton collision data at s=7 TeV recorded with the ATLAS experiment at the Large Hadron Collider. No significant excesses are observed with respect to the prediction from Standard Model processes. In the scenario of direct slepton production, if the sleptons decay directly into the lightest neutralino, left-handed slepton masses between 85 and 195 GeV are excluded at 95% confidence level for a 20 GeV neutralino. Chargino masses between 110 and 340 GeV are excluded in the scenario of direct production of wino-like chargino pairs decaying into the lightest neutralino via an intermediate on-shell charged slepton for a 10 GeV neutralino. The results are also interpreted in the framework of the phenomenological minimal supersymmetric Standard Model
Expressiveness of Probabilistic π-calculus

AbstractIn this work we propose a probabilistic extension of the π-calculus. The main novelty is a probabilistic mixed choice operator, that is, a choice construct with a probability distribution on the branches, and where input and output actions can both occur as guards. We develop the operational semantics of this calculus, and then we investigate its expressiveness. In particular, we compare it with the sublanguage with the two separate choices, where input and output guards are not allowed together in the same choice construct. Our main result is that the separate choices can encode the mixed one. Further, we show that input-guarded choice can encode output-guarded choice and viceversa. In contrast, we conjecture that neither of them can encode the pair of the two separate choices
Realistic two-nucleon potentials for the relativistic two-nucleon Schrödinger equation

AbstractThe potentials V (v) in the nonrelativistic (relativistic) nucleon–nucleon (NN) Schrödinger equation are related by a quadratic equation. That equation is numerically solved, thus providing phase equivalent v-potentials related for instance to the high precision NN potentials, which are adjusted to NN phase shift and mixing parameters in a nonrelativistic Schrödinger equation. The relativistic NN potentials embedded in a three-nucleon (3N) system for total NN momenta different from zero are also constructed in a numerically precise manner. They enter into the relativistic interacting 3N mass operator, which is needed for relativistic 3N calculations for bound and scattering states
Analyticity of layer potentials and L2 solvability of boundary value problems for divergence form elliptic equations with complex L∞ coefficients

AbstractWe consider divergence form elliptic operators of the form L=−divA(x)∇, defined in Rn+1={(x,t)∈Rn×R}, n⩾2, where the L∞ coefficient matrix A is (n+1)×(n+1), uniformly elliptic, complex and t-independent. We show that for such operators, boundedness and invertibility of the corresponding layer potential operators on L2(Rn)=L2(∂R+n+1), is stable under complex, L∞ perturbations of the coefficient matrix. Using a variant of the Tb Theorem, we also prove that the layer potentials are bounded and invertible on L2(Rn) whenever A(x) is real and symmetric (and thus, by our stability result, also when A is complex, ‖A−A0‖∞ is small enough and A0 is real, symmetric, L∞ and elliptic). In particular, we establish solvability of the Dirichlet and Neumann (and Regularity) problems, with L2 (resp. L˙12) data, for small complex perturbations of a real symmetric matrix. Previously, L2 solvability results for complex (or even real but non-symmetric) coefficients were known to hold only for perturbations of constant matrices (and then only for the Dirichlet problem), or in the special case that the coefficients Aj,n+1=0=An+1,j, 1⩽j⩽n, which corresponds to the Kato square root problem
Pygopus and Legless Provide Essential Transcriptional Coactivator Functions to Armadillo/β-Catenin

SummaryWnt signaling controls important aspects of animal development, and its deregulation has been causally linked to cancer. Transduction of Wnt signals entails the association of β-catenin with nuclear TCF DNA binding proteins and the subsequent activation of target genes. The transcriptional activity of Armadillo (Arm, the Drosophila β-catenin homolog) largely depends on two recently discovered components, Legless (Lgs) and Pygopus (Pygo). Lgs functions as an adaptor between Arm/β-catenin and Pygo, but different mechanisms have been proposed as to how Arm/β-catenin is controlled by Lgs and Pygo. Although Lgs and Pygo were originally thought to serve as nuclear cofactors for Arm/β-catenin to enhance its transactivation capacity, a recent analysis argued that they function instead to target Arm/β-catenin to the nucleus. Here, we used genetic assays in cultured cells and in vivo to discriminate between the two paradigms. Regardless of the measures taken to maintain the nuclear presence of Arm/β-catenin, a transcriptional-activation function of Pygo could not be bypassed. Our findings therefore indicate that Arm/β-catenin depends on Lgs and Pygo primarily for its transcriptional output rather than for its nuclear import
Effective actions of a Gauss–Bonnet brane world with brane curvature terms

AbstractWe consider a warped brane world scenario with two branes, Gauss–Bonnet gravity in the bulk, and brane localised curvature terms. When matter is present on both branes, we investigate the linear equations of motion and distinguish three regimes. At very high energy and for an observer on the positive tension brane, gravity is four-dimensional and coupled to the brane bending mode in a Brans–Dicke fashion. The coupling to matter and brane bending on the negative tension brane is exponentially suppressed. In an intermediate regime, gravity appears to be five dimensional while the brane bending mode remains four-dimensional. At low energy, matter on both branes couple to gravity for an observer on the positive tension brane, with a Brans–Dicke description similar to the 2-brane Randall–Sundrum setup. We also consider the zero mode truncation at low energy and show that the moduli approximation fails to reproduce the low energy action
Search for resonant pair production of Higgs bosons decaying to two bottom quark–antiquark pairs in proton–proton collisions at 8 TeV

AbstractA model-independent search for a narrow resonance produced in proton–proton collisions at s=8 TeV and decaying to a pair of 125 GeV Higgs bosons that in turn each decays into a bottom quark–antiquark pair is performed by the CMS experiment at the LHC. The analyzed data correspond to an integrated luminosity of 17.9 fb−1. No evidence for a signal is observed. Upper limits at a 95% confidence level on the production cross section for such a resonance, in the mass range from 270 to 1100 GeV, are reported. Using these results, a radion with decay constant of 1 TeV and mass from 300 to 1100 GeV, and a Kaluza–Klein graviton with mass from 380 to 830 GeV are excluded at a 95% confidence level
Effect of mobile telephones on sperm quality: A systematic review and meta-analysis

AbstractMobile phones are owned by most of the adult population worldwide. Radio-frequency electromagnetic radiation (RF-EMR) from these devices could potentially affect sperm development and function. Around 14% of couples in high- and middle-income countries have difficulty conceiving, and there are unexplained declines in semen quality reported in several countries. Given the ubiquity of mobile phone use, the potential role of this environmental exposure needs to be clarified. A systematic review was therefore conducted, followed by meta-analysis using random effects models, to determine whether exposure to RF-EMR emitted from mobile phones affects human sperm quality. Participants were from fertility clinic and research centres. The sperm quality outcome measures were motility, viability and concentration, which are the parameters most frequently used in clinical settings to assess fertility.We used ten studies in the meta-analysis, including 1492 samples. Exposure to mobile phones was associated with reduced sperm motility (mean difference −8.1% (95% CI −13.1, −3.2)) and viability (mean difference −9.1% (95% CI −18.4, 0.2)), but the effects on concentration were more equivocal. The results were consistent across experimental in vitro and observational in vivo studies. We conclude that pooled results from in vitro and in vivo studies suggest that mobile phone exposure negatively affects sperm quality. Further study is required to determine the full clinical implications for both sub-fertile men and the general population