Trends in the Dates of Ice Freeze-up and Breakup over Hudson Bay, Canada

Hudson Bay experiences a complete cryogenic cycle each year. Sea ice begins to form in late October, and the Bay is usually ice-free in early August. This seasonally varying ice cover plays an important role in the regional climate. To identify secular trends in the cryogenic cycle, we examined variability in the timing of sea-ice formation and retreat during the period 1971– 2003. The dates of ice freeze-up and breakup at 36 locations across Hudson Bay were catalogued for each year from weekly ice charts provided by the Canadian Ice Service. We used the nonparametric Mann-Kendall test to determine the statistical significance of the trends and the Theil-Sen approach to estimate their magnitude. Our results indicate statistically significant trends toward earlier breakup in James Bay, along the southern shore of Hudson Bay, and in the western half of Hudson Bay, and toward later freeze-up in the northern and northeastern regions of Hudson Bay. These trends in the annual ice cycle of Hudson Bay coincide with both the regional temperature record and the projections from general circulation models. If this trend toward a longer ice-free season continues, Hudson Bay will soon face important environmental challenges.Chaque année, la Baie d’Hudson connaît un cycle cryogénique complet. La formation de la glace marine commence en fin d’octobre et la baie est habituellement exempte de glace en début d’août. La présence saisonnière du couvert de la glace de la Baie d’Hudson revêt une importance primordiale sur le climat régional. Dans cet article, on étudie la variabilité des dates de formation et de retrait de la glace marine de la Baie d’Hudson dans le but d’identifier des tendances séculaires durant la période 1971 à 2003. Les dates de formation et de retrait de la glace marine ont été cataloguées pour tous les ans dans le cas de 36 endroits à travers la Baie d’Hudson et la Baie James en utilisant des images hebdomadaires publiées par le Service canadien des glaces. Le test non paramétrique Mann Kendall a été utilisé pour déterminer la signification statistique des tendances alors que la méthode de Theil Sen nous a fourni un estimé de l’ampleur de ces mêmes tendances. Notre analyse statistique nous indique qu’il existe des tendances significatives vers une date de déglacement plus avancée dans la Baie James, le long de la côte sud de la Baie d’Hudson, et dans la partie ouest de la Baie d’Hudson. De plus, des tendances significatives vers un gel plus tardif ont été observées dans les régions du nord et du nord-est de la Baie d’Hudson. Ces tendances dans le cycle annuel de glace de la Baie d’Hudson coïncident avec les tendances des températures de la région de même qu’avec les projections des modèles de circulation générale. Si cette tendance vers une durée plus courte du couvert de glace continue, la région de la Baie d’Hudson relèvera des défis environnementaux importants dans un proche avenir

Climate prediction of El Niño malaria epidemics in north-west Tanzania

Malaria is a significant public health problem in Tanzania. Approximately 16 million malaria cases are reported every year and 100,000 to 125,000 deaths occur. Although most of Tanzania is endemic to malaria, epidemics occur in the highlands, notably in Kagera, a region that was subject to widespread malaria epidemics in 1997 and 1998. This study examined the relationship between climate and malaria incidence in Kagera with the aim of determining whether seasonal forecasts may assist in predicting malaria epidemics. A regression analysis was performed on retrospective malaria and climatic data during each of the two annual malaria seasons to determine the climatic factors influencing malaria incidence. The ability of the DEMETER seasonal forecasting system in predicting the climatic anomalies associated with malaria epidemics was then assessed for each malaria season. It was found that malaria incidence is positively correlated with rainfall during the first season (Oct-Mar) (R-squared = 0.73, p < 0.01). For the second season (Apr-Sep), high malaria incidence was associated with increased rainfall, but also with high maximum temperature during the first rainy season (multiple R-squared = 0.79, p < 0.01). The robustness of these statistical models was tested by excluding the two epidemic years from the regression analysis. DEMETER would have been unable to predict the heavy El Niño rains associated with the 1998 epidemic. Nevertheless, this epidemic could still have been predicted using the temperature forecasts alone. The 1997 epidemic could have been predicted from observed temperatures in the preceding season, but the consideration of the rainfall forecasts would have improved the temperature-only forecasts over the remaining years. These results demonstrate the potential of a seasonal forecasting system in the development of a malaria early warning system in Kagera region

Transformation in a changing climate: a research agenda

The concept of transformation in relation to climate and other global change is increasingly receiving attention. The concept provides important opportunities to help examine how rapid and fundamental change to address contemporary global challenges can be facilitated. This paper contributes to discussions about transformation by providing a social science, arts and humanities perspective to open up discussion and set out a research agenda about what it means to transform and the dimensions, limitations and possibilities for transformation. Key focal areas include: (1) change theories, (2) knowing whether transformation has occurred or is occurring; (3) knowledge production and use; (4), governance; (5) how dimensions of social justice inform transformation; (6) the limits of human nature; (7) the role of the utopian impulse; (8) working with the present to create new futures; and (9) human consciousness. In addition to presenting a set of research questions around these themes the paper highlights that much deeper engagement with complex social processes is required; that there are vast opportunities for social science, humanities and the arts to engage more directly with the climate challenge; that there is a need for a massive upscaling of efforts to understand and shape desired forms of change; and that, in addition to helping answer important questions about how to facilitate change, a key role of the social sciences, humanities and the arts in addressing climate change is to critique current societal patterns and to open up new thinking. Through such critique and by being more explicit about what is meant by transformation, greater opportunities will be provided for opening up a dialogue about change, possible futures and about what it means to re-shape the way in which people live

Can nature-based solutions contribute to water security in Bhopal?

Bhojtal, a large man-made lake bordering the city of Bhopal (Madhya Pradesh state, central India), is important for the city’s water supply, connoted the lifeline of the city. Despite the dry though not arid and markedly seasonal climate, soil impermeability hampers infiltration into the complex geology underlying the Bhojtal catchment. Rural communities in the catchment are nonetheless high dependent on underlying aquifers. This paper develops baseline understanding of trends in the ecology, water quality and uses of Bhojtal, discussing their implications for the long-term wellbeing of the Bhopal city region. It highlights increasing dependency on water diverted from out-of-catchment sources, and also abstraction across the Bhojtal catchment in excess of replenishment that is depressing groundwater and contributing to reported declining lake level and water quality. Despite some nature-based management initiatives, evidence suggests little progress in haltering on-going groundwater depression and declines in lake water level and quality. Significant declines in ecosystem services produced by Bhojtal are likely without intervention, a major concern given the high dependency of people in the Bhopal region on Bhojtal for their water supply and socio-economic and cultural wellbeing. Over-reliance on appropriation of water from increasingly remote sources is currently compensating for lack of attention to measures protecting or regenerating local resources that may provide greater resilience and regional self-sufficiency. Improved knowledge of catchment hydrogeology on a highly localised scale could improve the targeting and efficiency of water harvesting and other management interventions in the Bhojtal catchment, and their appropriate hybridisation with engineered solutions, protecting the catchment from unintended impacts of water extraction or increasing its carrying capacity, and also providing resilience to rising population and climate change. Ecosystem service assessment provides useful insights into the breadth of benefits of improved management of Bhojtal and its catchment

Distinct Effects of Two HIV-1 Capsid Assembly Inhibitor Families That Bind the Same Site within the N-Terminal Domain of the Viral CA Protein

The emergence of resistance to existing classes of antiretroviral drugs necessitates finding new HIV-1 targets for drug discovery. The viral capsid (CA) protein represents one such potential new target. CA is sufficient to form mature HIV-1 capsids in vitro, and extensive structure-function and mutational analyses of CA have shown that the proper assembly, morphology, and stability of the mature capsid core are essential for the infectivity of HIV-1 virions. Here we describe the development of an in vitro capsid assembly assay based on the association of CA-NC subunits on immobilized oligonucleotides. This assay was used to screen a compound library, yielding several different families of compounds that inhibited capsid assembly. Optimization of two chemical series, termed the benzodiazepines (BD) and the benzimidazoles (BM), resulted in compounds with potent antiviral activity against wild-type and drug-resistant HIV-1. Nuclear magnetic resonance (NMR) spectroscopic and X-ray crystallographic analyses showed that both series of inhibitors bound to the N-terminal domain of CA. These inhibitors induce the formation of a pocket that overlaps with the binding site for the previously reported CAP inhibitors but is expanded significantly by these new, more potent CA inhibitors. Virus release and electron microscopic (EM) studies showed that the BD compounds prevented virion release, whereas the BM compounds inhibited the formation of the mature capsid. Passage of virus in the presence of the inhibitors selected for resistance mutations that mapped to highly conserved residues surrounding the inhibitor binding pocket, but also to the C-terminal domain of CA. The resistance mutations selected by the two series differed, consistent with differences in their interactions within the pocket, and most also impaired virus replicative capacity. Resistance mutations had two modes of action, either directly impacting inhibitor binding affinity or apparently increasing the overall stability of the viral capsid without affecting inhibitor binding. These studies demonstrate that CA is a viable antiviral target and demonstrate that inhibitors that bind within the same site on CA can have distinct binding modes and mechanisms of action

Measurement of the cross-section and charge asymmetry of WW bosons produced in proton-proton collisions at s=8\sqrt{s}=8 TeV with the ATLAS detector

This paper presents measurements of the $W^+ \rightarrow \mu^+\nu$ and $W^- \rightarrow \mu^-\nu$ cross-sections and the associated charge asymmetry as a function of the absolute pseudorapidity of the decay muon. The data were collected in proton--proton collisions at a centre-of-mass energy of 8 TeV with the ATLAS experiment at the LHC and correspond to a total integrated luminosity of 20.2~\mbox{fb^{-1}}. The precision of the cross-section measurements varies between 0.8% to 1.5% as a function of the pseudorapidity, excluding the 1.9% uncertainty on the integrated luminosity. The charge asymmetry is measured with an uncertainty between 0.002 and 0.003. The results are compared with predictions based on next-to-next-to-leading-order calculations with various parton distribution functions and have the sensitivity to discriminate between them.Comment: 38 pages in total, author list starting page 22, 5 figures, 4 tables, submitted to EPJC. All figures including auxiliary figures are available at https://atlas.web.cern.ch/Atlas/GROUPS/PHYSICS/PAPERS/STDM-2017-13

Measurements of fiducial and differential cross sections for Higgs boson production in the diphoton decay channel at s√=8 TeV with ATLAS

Measurements of fiducial and differential cross sections are presented for Higgs boson production in proton-proton collisions at a centre-of-mass energy of s√=8 TeV. The analysis is performed in the H → γγ decay channel using 20.3 fb−1 of data recorded by the ATLAS experiment at the CERN Large Hadron Collider. The signal is extracted using a fit to the diphoton invariant mass spectrum assuming that the width of the resonance is much smaller than the experimental resolution. The signal yields are corrected for the effects of detector inefficiency and resolution. The pp → H → γγ fiducial cross section is measured to be 43.2 ±9.4(stat.) − 2.9 + 3.2 (syst.) ±1.2(lumi)fb for a Higgs boson of mass 125.4GeV decaying to two isolated photons that have transverse momentum greater than 35% and 25% of the diphoton invariant mass and each with absolute pseudorapidity less than 2.37. Four additional fiducial cross sections and two cross-section limits are presented in phase space regions that test the theoretical modelling of different Higgs boson production mechanisms, or are sensitive to physics beyond the Standard Model. Differential cross sections are also presented, as a function of variables related to the diphoton kinematics and the jet activity produced in the Higgs boson events. The observed spectra are statistically limited but broadly in line with the theoretical expectations

Measurement of the production of a W boson in association with a charm quark in pp collisions at √s = 7 TeV with the ATLAS detector

The production of a W boson in association with a single charm quark is studied using 4.6 fb−1 of pp collision data at s√ = 7 TeV collected with the ATLAS detector at the Large Hadron Collider. In events in which a W boson decays to an electron or muon, the charm quark is tagged either by its semileptonic decay to a muon or by the presence of a charmed meson. The integrated and differential cross sections as a function of the pseudorapidity of the lepton from the W-boson decay are measured. Results are compared to the predictions of next-to-leading-order QCD calculations obtained from various parton distribution function parameterisations. The ratio of the strange-to-down sea-quark distributions is determined to be 0.96+0.26−0.30 at Q 2 = 1.9 GeV2, which supports the hypothesis of an SU(3)-symmetric composition of the light-quark sea. Additionally, the cross-section ratio σ(W + +c¯¯)/σ(W − + c) is compared to the predictions obtained using parton distribution function parameterisations with different assumptions about the s−s¯¯¯ quark asymmetry

Measurement of χ c1 and χ c2 production with s√ = 7 TeV pp collisions at ATLAS

The prompt and non-prompt production cross-sections for the χ c1 and χ c2 charmonium states are measured in pp collisions at s√ = 7 TeV with the ATLAS detector at the LHC using 4.5 fb−1 of integrated luminosity. The χ c states are reconstructed through the radiative decay χ c → J/ψγ (with J/ψ → μ + μ −) where photons are reconstructed from γ → e + e − conversions. The production rate of the χ c2 state relative to the χ c1 state is measured for prompt and non-prompt χ c as a function of J/ψ transverse momentum. The prompt χ c cross-sections are combined with existing measurements of prompt J/ψ production to derive the fraction of prompt J/ψ produced in feed-down from χ c decays. The fractions of χ c1 and χ c2 produced in b-hadron decays are also measured