Showing papers by "Paul Sabatier University published in 2013"
TL;DR: This work quantifies the kinetics of charge storage in T-Nb2O5: currents that vary inversely with time, charge-storage capacity that is mostly independent of rate, and redox peaks that exhibit small voltage offsets even at high rates.
Abstract: Pseudocapacitance is commonly associated with surface or near-surface reversible redox reactions, as observed with RuO2·xH2O in an acidic electrolyte. However, we recently demonstrated that a pseudocapacitive mechanism occurs when lithium ions are inserted into mesoporous and nanocrystal films of orthorhombic Nb2O5 (T-Nb2O5; refs 1, 2). Here, we quantify the kinetics of charge storage in T-Nb2O5: currents that vary inversely with time, charge-storage capacity that is mostly independent of rate, and redox peaks that exhibit small voltage offsets even at high rates. We also define the structural characteristics necessary for this process, termed intercalation pseudocapacitance, which are a crystalline network that offers two-dimensional transport pathways and little structural change on intercalation. The principal benefit realized from intercalation pseudocapacitance is that high levels of charge storage are achieved within short periods of time because there are no limitations from solid-state diffusion. Thick electrodes (up to 40 μm thick) prepared with T-Nb2O5 offer the promise of exploiting intercalation pseudocapacitance to obtain high-rate charge-storage devices.
3,725 citations
TL;DR: This study demonstrates the spontaneous intercalation of cations from aqueous salt solutions between two-dimensional (2D) Ti3C2 MXene layers, and provides a basis for exploring a large family of 2D carbides and carbonitrides in electrochemical energy storage applications using single- and multivalent ions.
Abstract: The intercalation of ions into layered compounds has long been exploited in energy storage devices such as batteries and electrochemical capacitors However, few host materials are known for ions much larger than lithium We demonstrate the spontaneous intercalation of cations from aqueous salt solutions between two-dimensional (2D) Ti3C2 MXene layers MXenes combine 2D conductive carbide layers with a hydrophilic, primarily hydroxyl-terminated surface A variety of cations, including Na+, K+, NH4+, Mg2+, and Al3+, can also be intercalated electrochemically, offering capacitance in excess of 300 farads per cubic centimeter (much higher than that of porous carbons) This study provides a basis for exploring a large family of 2D carbides and carbonitrides in electrochemical energy storage applications using single- and multivalent ions
3,018 citations
University of Tennessee1, Centre national de la recherche scientifique2, International Union for Conservation of Nature and Natural Resources3, Swedish University of Agricultural Sciences4, Missouri Botanical Garden5, University of Paris-Sud6, University of Girona7, Institut national de la recherche agronomique8, Charles University in Prague9, Academy of Sciences of the Czech Republic10, University of Porto11, University of Minho12, Paul Sabatier University13, Spanish National Research Council14
TL;DR: Recent progress in understanding invasion impacts and management is highlighted, and the challenges that the discipline faces in its science and interactions with society are discussed.
Abstract: Study of the impacts of biological invasions, a pervasive component of global change, has generated remarkable understanding of the mechanisms and consequences of the spread of introduced populations. The growing field of invasion science, poised at a crossroads where ecology, social sciences, resource management, and public perception meet, is increasingly exposed to critical scrutiny from several perspectives. Although the rate of biological invasions, elucidation of their consequences, and knowledge about mitigation are growing rapidly, the very need for invasion science is disputed. Here, we highlight recent progress in understanding invasion impacts and management, and discuss the challenges that the discipline faces in its science and interactions with society.
2,346 citations
TL;DR: Empirical evidence is synthesized and a theoretical framework, based on species positions in a functional space, as a tool to reveal the complex nature of change in disturbed ecosystems is presented.
Abstract: Understanding the processes shaping biological communities under multiple disturbances is a core challenge in ecology and conservation science. Traditionally, ecologists have explored linkages between the severity and type of disturbance and the taxonomic structure of communities. Recent advances in the application of species traits, to assess the functional structure of communities, have provided an alternative approach that responds rapidly and consistently across taxa and ecosystems to multiple disturbances. Importantly, trait-based metrics may provide advanced warning of disturbance to ecosystems because they do not need species loss to be reactive. Here, we synthesize empirical evidence and present a theoretical framework, based on species positions in a functional space, as a tool to reveal the complex nature of change in disturbed ecosystems.
1,307 citations
TL;DR: Overall, the combination of the right electrode materials with a proper electrolyte can successfully increase both the energy stored by the device and its power, but no perfect active material exists and no electrolyte suits every material and every performance goal.
Abstract: Securing our energy future is the most important problem that humanity faces in this century. Burning fossil fuels is not sustainable, and wide use of renewable energy sources will require a drastically increased ability to store electrical energy. In the move toward an electrical economy, chemical (batteries) and capacitive energy storage (electrochemical capacitors or supercapacitors) devices are expected to play an important role. This Account summarizes research in the field of electrochemical capacitors conducted over the past decade.Overall, the combination of the right electrode materials with a proper electrolyte can successfully increase both the energy stored by the device and its power, but no perfect active material exists and no electrolyte suits every material and every performance goal. However, today, many materials are available, including porous activated, carbide-derived, and templated carbons with high surface areas and porosities that range from subnanometer to just a few nanometers. ...
1,284 citations
Utrecht University1, Naturalis2, Duke University3, Institut de recherche pour le développement4, Institut national de la recherche agronomique5, Museu Paraense Emílio Goeldi6, University of California, Berkeley7, University of Leeds8, Empresa Brasileira de Pesquisa Agropecuária9, National Institute of Amazonian Research10, National University of Saint Anthony the Abbot in Cuzco11, University of Exeter12, World Wide Fund for Nature13, Universidad Autónoma Gabriel René Moreno14, Norwegian University of Life Sciences15, Max Planck Society16, James Cook University17, Universidade do Estado de Mato Grosso18, University of Amsterdam19, Silver Spring Networks20, State University of Campinas21, University of Edinburgh22, University of Los Andes23, Smithsonian Conservation Biology Institute24, National University of Colombia25, University of East Anglia26, Central University of Ecuador27, Centre national de la recherche scientifique28, Humboldt State University29, New York Botanical Garden30, Universidade Federal do Acre31, Paul Sabatier University32, Missouri Botanical Garden33, Amazon.com34, University of Texas at Austin35, University of Florida36, Venezuelan Institute for Scientific Research37, Environmental Change Institute38, Federal Rural University of Amazonia39, University of São Paulo40, State University of Norte Fluminense41, University of Wisconsin–Milwaukee42, Smithsonian Tropical Research Institute43, Northern Arizona University44, Aarhus University45, Tropenbos International46, University of Kent47, Royal Botanic Gardens48, Universidad Nacional de la Amazonía Peruana49, University of Missouri–St. Louis50, Florida International University51, Fairchild Tropical Botanic Garden52, Wake Forest University53
TL;DR: The finding that Amazonia is dominated by just 227 tree species implies that most biogeochemical cycling in the world’s largest tropical forest is performed by a tiny sliver of its diversity.
Abstract: The vast extent of the Amazon Basin has historically restricted the study of its tree communities to the local and regional scales. Here, we provide empirical data on the commonness, rarity, and richness of lowland tree species across the entire Amazon Basin and Guiana Shield (Amazonia), collected in 1170 tree plots in all major forest types. Extrapolations suggest that Amazonia harbors roughly 16,000 tree species, of which just 227 (1.4%) account for half of all trees. Most of these are habitat specialists and only dominant in one or two regions of the basin. We discuss some implications of the finding that a small group of species—less diverse than the North American tree flora—accounts for half of the world’s most diverse tree community.
963 citations
TL;DR: It is argued that conceptual unification across ecology, genetics, evolution and physiology has fostered even more fertile questions that have far reaching implications for the understanding of how ecosystem function and biodiversity will withstand environmental changes in the 21st century.
Abstract: Over the past 20 years, major advances have clarified how ecological patterns inform theory, and how in turn theory informs applied ecology. Also, there has been an increased recognition that the problem of scale at which ecological processes should be considered is critical if we are to produce general predictions. Ecological dynamics is always stochastic at small scales, but variability is conditional on the scale of description. The radical changes in the scope and aims of ecology over the past decades reflect in part the need to address pressing societal issues of environmental change. Technological advances in molecular biology, global positioning, sensing instrumentation and computational power should not be overlooked as an explanation for these radical changes. However, I argue that conceptual unification across ecology, genetics, evolution and physiology has fostered even more fertile questions. We are moving away from the view that evolution is played in a fixed ecological theatre: the theatre is being rapidly and relentlessly redesigned by the players themselves. The maintenance of ecosystem functions depends on shifts in species assemblages and on cellular metabolism, not only on flows of energy and matter. These findings have far reaching implications for our understanding of how ecosystem function and biodiversity will withstand (or not) environmental changes in the 21st century.
862 citations
TL;DR: The most unusual, and thus irreplaceable, functions performed by species in three different species-rich ecosystems are fulfilled by only the rare species in these ecosystems.
Abstract: Around the world, the human-induced collapses of populations and species have triggered a sixth mass extinction crisis, with rare species often being the first to disappear. Although the role of species diversity in the maintenance of ecosystem processes has been widely investigated, the role of rare species remains controversial. A critical issue is whether common species insure against the loss of functions supported by rare species. This issue is even more critical in species-rich ecosystems where high functional redundancy among species is likely and where it is thus often assumed that ecosystem functioning is buffered against species loss. Here, using extensive datasets of species occurrences and functional traits from three highly diverse ecosystems (846 coral reef fishes, 2,979 alpine plants, and 662 tropical trees), we demonstrate that the most distinct combinations of traits are supported predominantly by rare species both in terms of local abundance and regional occupancy. Moreover, species that have low functional redundancy and are likely to support the most vulnerable functions, with no other species carrying similar combinations of traits, are rarer than expected by chance in all three ecosystems. For instance, 63% and 98% of fish species that are likely to support highly vulnerable functions in coral reef ecosystems are locally and regionally rare, respectively. For alpine plants, 32% and 89% of such species are locally and regionally rare, respectively. Remarkably, 47% of fish species and 55% of tropical tree species that are likely to support highly vulnerable functions have only one individual per sample on average. Our results emphasize the importance of rare species conservation, even in highly diverse ecosystems, which are thought to exhibit high functional redundancy. Rare species offer more than aesthetic, cultural, or taxonomic diversity value; they disproportionately increase the potential breadth of functions provided by ecosystems across spatial scales. As such, they are likely to insure against future uncertainty arising from climate change and the ever-increasing anthropogenic pressures on ecosystems. Our results call for a more detailed understanding of the role of rarity and functional vulnerability in ecosystem functioning.
679 citations
TL;DR: Molecular dynamics simulations of realistic supercapacitors are performed and it is shown that both the desolvation and the local charge stored on the electrode increase with the degree of confinement.
Abstract: Liquids exhibit specific properties when they are adsorbed in nanoporous structures. This is particularly true in the context of supercapacitors, for which an anomalous increase in performance has been observed for nanoporous electrodes. This enhancement has been traditionally attributed in experimental studies to the effect of confinement of the ions from the electrolyte inside sub-nanometre pores, which is accompanied by their partial desolvation. Here we perform molecular dynamics simulations of realistic supercapacitors and show that this picture is correct at the microscopic scale. We provide a detailed analysis of the various environments experienced by the ions. We pick out four different adsorption types, and we, respectively, label them as edge, planar, hollow and pocket sites upon increase of the coordination of the molecular species by carbon atoms from the electrode. We show that both the desolvation and the local charge stored on the electrode increase with the degree of confinement.
585 citations
TL;DR: In this article, a measure-and-sort approach was used to achieve sub-10 fs root-mean-squared (rms) error measurement at hard X-ray FELs, far beyond the 100-200 fs rms jitter limitations.
Abstract: Recently, few-femtosecond pulses have become available at hard X-ray free-electron lasers Coupled with the available sub-10 fs optical pulses, investigations into few-femtosecond dynamics are not far off However, achieving sufficient synchronization between optical lasers and X-ray pulses continues to be challenging We report a 'measure-and-sort' approach, which achieves sub-10 fs root-mean-squared (rms) error measurement at hard X-ray FELs, far beyond the 100-200 fs rms jitter limitations This timing diagnostic, now routinely available at the Linac Coherent Light Source (LCLS), is based on ultrafast free-carrier generation in optically transparent materials Correlation between two independent measurements enables unambiguous demonstration of ~6 fs rms error in reporting the optical/X-ray delay, with single shot error suggesting the possibility of reaching few-femtosecond resolution
337 citations
TL;DR: Control, emotional feeding, encouragement to eat, weight-based restriction and fat restriction were associated prospectively with the development of obesogenic eating behaviors in children including emotional eating, tendency to overeat and food approach behaviors (such as enjoyment of food and good appetite).
Abstract: Maternal feeding practices have been proposed to play an important role in early child weight gain and obesogenic eating behaviors. However, to date longitudinal investigations in young children exploring these relationships have been lacking. The aim of the present study was to explore prospective relationships between maternal feeding practices, child weight gain and obesogenic eating behaviors in 2-year-old children. The competing hypothesis that child eating behaviors predict changes in maternal feeding practices was also examined. A sample of 323 mother (mean age = 35 years, ± 0.37) and child dyads (mean age = 2.03 years, ± 0.37 at recruitment) were participants. Mothers completed a questionnaire assessing parental feeding practices and child eating behaviors at baseline and again one year later. Child BMI (predominantly objectively measured) was obtained at both time points. Increases in child BMI z-scores over the follow-up period were predicted by maternal instrumental feeding practices. Furthermore, restriction, emotional feeding, encouragement to eat, weight-based restriction and fat restriction were associated prospectively with the development of obesogenic eating behaviors in children including emotional eating, tendency to overeat and food approach behaviors (such as enjoyment of food and good appetite). Maternal monitoring, however, predicted decreases in food approach eating behaviors. Partial support was also observed for child eating behaviors predicting maternal feeding practices. Maternal feeding practices play an important role in the development of weight gain and obesogenic eating behaviors in young children and are potential targets for effective prevention interventions aiming to decrease child obesity.
TL;DR: Toen and Vezzosi as discussed by the authors introduced the notion of n-shifted symplectic structures (n-symplectic structures for short), a generalization of the concept of symplectic structure on smooth varieties and schemes, meaningful in the setting of derived Artin n-stacks.
Abstract: This is the first of a series of papers about quantization in the context of derived algebraic geometry. In this first part, we introduce the notion of n-shifted symplectic structures (n-symplectic structures for short), a generalization of the notion of symplectic structures on smooth varieties and schemes, meaningful in the setting of derived Artin n-stacks (see Toen and Vezzosi in Mem. Am. Math. Soc. 193, 2008 and Toen in Proc. Symp. Pure Math. 80:435–487, 2009). We prove that classifying stacks of reductive groups, as well as the derived stack of perfect complexes, carry canonical 2-symplectic structures. Our main existence theorem states that for any derived Artin stack F equipped with an n-symplectic structure, the derived mapping stack Map(X,F) is equipped with a canonical (n−d)-symplectic structure as soon a X satisfies a Calabi-Yau condition in dimension d. These two results imply the existence of many examples of derived moduli stacks equipped with n-symplectic structures, such as the derived moduli of perfect complexes on Calabi-Yau varieties, or the derived moduli stack of perfect complexes of local systems on a compact and oriented topological manifold. We explain how the known symplectic structures on smooth moduli spaces of simple objects (e.g. simple sheaves on Calabi-Yau surfaces, or simple representations of π1 of compact Riemann surfaces) can be recovered from our results, and that they extend canonically as 0-symplectic structures outside of the smooth locus of simple objects. We also deduce new existence statements, such as the existence of a natural (−1)-symplectic structure (whose formal counterpart has been previously constructed in (Costello, arXiv:1111.4234, 2001) and (Costello and Gwilliam, 2011) on the derived mapping scheme Map(E,T∗X), for E an elliptic curve and T∗X is the total space of the cotangent bundle of a smooth scheme X. Canonical (−1)-symplectic structures are also shown to exist on Lagrangian intersections, on moduli of sheaves (or complexes of sheaves) on Calabi-Yau 3-folds, and on moduli of representations of π1 of compact topological 3-manifolds. More generally, the moduli sheaves on higher dimensional varieties are shown to carry canonical shifted symplectic structures (with a shift depending on the dimension).
TL;DR: In this paper, a carbon-ionic liquid system with high capacitance of up to 180 F/g and wide electrochemical window (up to 3.5 V) over a wide temperature range from −50 °C to 80 °C.
TL;DR: A decomposition of functional β-diversity, i.e. the dissimilarity in functional composition between communities, is developed into a functional turnover and a functional nestedness-resultant component.
Abstract: Aim
One of the main gaps in the assessment of biodiversity is the lack of a unified framework for measuring its taxonomic and functional facets and for unveiling the underlying patterns.
Location
Europe, 25 large river basins.
Methods
Here, we develop a decomposition of functional β-diversity, i.e. the dissimilarity in functional composition between communities, into a functional turnover and a functional nestedness-resultant component.
Results
We found that functional β-diversity was lower than taxonomic β-diversity. This difference was driven by a lower functional turnover compared with taxonomic turnover while the nestedness-resultant component was similar for taxonomic and functional β-diversity.
Main conclusions
Fish faunas with different species tend to share the same functional attributes. The framework presented in this paper will help to analyse biogeographical patterns as well as to measure the impact of human activities on the functional facets of biodiversity.
Université de Montréal1, Karolinska Institutet2, University of Wisconsin-Madison3, Paul Sabatier University4, Aarhus University5, University of Sydney6, Université catholique de Louvain7, University of Toronto8, Harvard University9, University of Kansas10, University of California, Berkeley11, University of California, Los Angeles12, University of New South Wales13, Imperial College London14, Erasmus University Rotterdam15, University of Gothenburg16, Duke University17, Ohio University18, National Institutes of Health19, University of Florida20, New York Medical College21, French Institute of Health and Medical Research22, University of Pittsburgh23, Rutgers University24, University of Kentucky25, University of Helsinki26, McMaster University27, University of Queensland28
TL;DR: Following a multidisciplinary evaluation, preferably by experts, rhGH treatment should be considered for patients with genetically confirmed PWS in conjunction with dietary, environmental, and lifestyle interventions.
Abstract: Context: Recombinant human GH (rhGH) therapy in Prader-Willi syndrome (PWS) has been used by the medical community and advocated by parental support groups since its approval in the United States in 2000 and in Europe in 2001. Its use in PWS represents a unique therapeutic challenge that includes treating individuals with cognitive disability, varied therapeutic goals that are not focused exclusively on increased height, and concerns about potential life-threatening adverse events. Objective: The aim of the study was to formulate recommendations for the use of rhGH in children and adult patients with PWS. Evidence: We performed a systematic review of the clinical evidence in the pediatric population, including randomized controlled trials, comparative observational studies, and long-term studies (>3.5 y). Adult studies included randomized controlled trials of rhGH treatment for ≥6 months and uncontrolled trials. Safety data were obtained from case reports, clinical trials, and pharmaceutical registries. Methodology: Forty-three international experts and stakeholders followed clinical practice guideline development recommendations outlined by the AGREE Collaboration (www.agreetrust.org). Evidence was synthesized and graded using a comprehensive multicriteria methodology (EVIDEM) (http://bit.ly.PWGHIN). Conclusions: Following a multidisciplinary evaluation, preferably by experts, rhGH treatment should be considered for patients with genetically confirmed PWS in conjunction with dietary, environmental, and lifestyle interventions. Cognitive impairment should not be a barrier to treatment, and informed consent/assent should include benefit/risk information. Exclusion criteria should include severe obesity, uncontrolled diabetes mellitus, untreated severe obstructive sleep apnea, active cancer, or psychosis. Clinical outcome priorities should vary depending upon age and the presence of physical, mental, and social disability, and treatment should be continued for as long as demonstrated benefits outweigh the risks. Copyright
TL;DR: Previous epidemiological studies have demonstrated a high prevalence of cardiovascular risk factors in psoriasis patients, including metabolic syndrome, cigarette smoking, obesity, hypertension, diabetes mellitus, insulin resistance and dyslipidaemia.
Abstract: Previous epidemiological studies have demonstrated a high prevalence of cardiovascular (CV) risk factors in psoriasis patients, including metabolic syndrome, cigarette smoking, obesity, hypertension, diabetes mellitus, insulin resistance and dyslipidaemia. An increase in CV morbidity and mortality attributable to psoriasis is still under question.
Primary objective: to assess CV morbidity and mortality in psoriasis and psoriatic arthritis (PsA) including stroke, coronary artery disease, myocardial infarction (MI) and peripheral artery disease. Secondary objectives: to assess if psoriasis per se is an independent CV risk factor and if psoriasis severity is a predictor of CV risk. We also evaluated the effect of conventional systemic treatments for psoriasis on CV mortality.
A systematic literature search was carried out from 1980 to December 2011, in the Embase, Medline and Cochrane Library databases, in English and French using a combination of keywords including (Psoriasis) OR (Psoriatic arthritis) AND (Myocardial infarction) OR (Coronaropathy) OR (Stroke) OR (Cardiovascular) AND (Methotrexate) AND (Ciclosporin) AND (Retinoids).
Of the 929 identified references, 33 observational studies evaluating the rates of cardiovascular events (CVE) in patients with psoriasis and PsA compared with controls were selected. Meta-analysis of both cohort and cross-sectional studies showed an increased risk of MI with Odds Ratio (OR) of 1.25 (95% CI 1.03–1.52) and 1.57 (95% CI 1.08–2.27) in psoriasis and PsA, respectively, compared with the general population. The risk of MI was more pronounced for patients having severe psoriasis and for patients with psoriasis of early onset. It remained significantly elevated after controlling for major CV risk factors. The meta-analysis identified a small, but significant association between psoriasis, PsA and coronary artery disease with an OR between 1.19 (95% CI 1.14–1.24) for cross-sectional studies, 1.20 (95% CI 1.13–1.27) for cohort studies and 1.84 (95% CI 1.09–3.09) for case–control studies. The risk of coronary artery disease seemed to be more pronounced in patients with severe psoriasis and in patients with psoriasis of early onset. The meta-analysis assessing the risk of stroke gave inconclusive results: analysis of cross-sectional studies suggested that psoriasis patients had a slightly higher risk of stroke with an OR of 1.14 (95% CI 1.08–1.99), whereas the meta-analysis of cohort studies failed to show an association. There was also an increased risk of peripheral artery disease in psoriasis. No significant increased risk of CV mortality could be shown for both psoriasis and PsA patients. The use of methotrexate was associated with a reduced incidence of cardiovascular disease in two studies. The use of etretinate was associated with a reduction of CV mortality in one study. Potential selection bias such as the ‘healthy user effect’ prevents from drawing definite conclusions.
There may be a small, but significant increased risk of CVE, but not of CV mortality in psoriasis and PsA patients. The psoriasis attributable risk remains difficult to assess due to confounding factors. The moderate quality of CV risk factors reporting in studies should be acknowledged. In addition, heterogeneity in study design, outcome definition and assessment represent major limitations. Nevertheless, screening and management of CV risk factors are important in psoriasis.
TL;DR: In this article, a more asymmetric diblock copolymer formulation is presented, which is the first time that higher order morphologies (e.g. worms and vesicles) have been accessed in non-polar solvents and is expected to have potential boundary lubrication applications for engine oils.
Abstract: Well-defined poly(lauryl methacrylate-benzyl methacrylate) (PLMA-PBzMA) diblock copolymer nanoparticles are prepared in n-heptane at 90 °C via reversible addition–fragmentation chain transfer (RAFT) polymerization. Under these conditions, the PLMA macromolecular chain transfer agent (macro-CTA) is soluble in n-heptane, whereas the growing PBzMA block quickly becomes insoluble. Thus this dispersion polymerization formulation leads to polymerization-induced self-assembly (PISA). Using a relatively long PLMA macro-CTA with a mean degree of polymerization (DP) of 37 or higher leads to the formation of well-defined spherical nanoparticles of 41 to 139 nm diameter, depending on the DP targeted for the PBzMA block. In contrast, TEM studies confirm that using a relatively short PLMA macro-CTA (DP = 17) enables both worm-like and vesicular morphologies to be produced, in addition to the spherical phase. A detailed phase diagram has been elucidated for this more asymmetric diblock copolymer formulation, which ensures that each pure phase can be targeted reproducibly. 1H NMR spectroscopy confirmed that high BzMA monomer conversions (>97%) were achieved within 5 h, while GPC studies indicated that reasonably good blocking efficiencies and relatively low diblock copolymer polydispersities (Mw/Mn < 1.30) were obtained in most cases. Compared to prior literature reports, this all-methacrylic PISA formulation is particularly novel because: (i) it is the first time that higher order morphologies (e.g. worms and vesicles) have been accessed in non-polar solvents and (ii) such diblock copolymer nano-objects are expected to have potential boundary lubrication applications for engine oils.
TL;DR: In this article, the degenerate complex Monge-Ampere equations in a big cohomology class of a compact Kahler manifold can be solved using a variational method, without relying on Yau's theorem.
Abstract: We show that degenerate complex Monge-Ampere equations in a big cohomology class of a compact Kahler manifold can be solved using a variational method, without relying on Yau’s theorem. Our formulation yields in particular a natural pluricomplex analogue of the classical logarithmic energy of a measure. We also investigate Kahler-Einstein equations on Fano manifolds. Using continuous geodesics in the closure of the space of Kahler metrics and Berndtsson’s positivity of direct images, we extend Ding-Tian’s variational characterization and Bando-Mabuchi’s uniqueness result to singular Kahler-Einstein metrics. Finally, using our variational characterization we prove the existence, uniqueness and convergence as k→∞ of k-balanced metrics in the sense of Donaldson both in the (anti)canonical case and with respect to a measure of finite pluricomplex energy.
TL;DR: It is shown that upon application of a constant applied potential difference, the increase in the temperature, due to the Joule effect, associated with the creation of an electric current across the cell follows Ohm's law, while unphysically high temperatures are rapidly observed when constant charges are assigned to each carbon atom.
Abstract: Supercapacitors based on an ionic liquid electrolyte and graphite or nanoporous carbon electrodes are simulated using molecular dynamics. We compare a simplified electrode model in which a constant, uniform charge is assigned to each carbon atom with a realistic model in which a constant potential is applied between the electrodes (the carbon charges are allowed to fluctuate). We show that the simulations performed with the simplified model do not provide a correct description of the properties of the system. First, the structure of the adsorbed electrolyte is partly modified. Second, dramatic differences are observed for the dynamics of the system during transient regimes. In particular, upon application of a constant applied potential difference, the increase in the temperature, due to the Joule effect, associated with the creation of an electric current across the cell follows Ohm’s law, while unphysically high temperatures are rapidly observed when constant charges are assigned to each carbon atom.
TL;DR: It is demonstrated for the first time that targeting oncogenic miRNA strongly inhibit pancreatic cancer tumor growth both in vitro and in vivo.
TL;DR: In this article, the authors studied the mobility of rare earth elements (REE) in non-polluted natural soil-plant systems in order to characterize their environmental availability for future anthropogenic pollution.
Abstract: Rare Earth Elements (REE) are widely used to trace natural geochemical processes. They are also increasingly used by man (electronics industry, medicine, agriculture) and therefore considered as emerging pollutants. The present study documents REE mobility in non-polluted natural soil-plant systems in order to characterize their environmental availability for future anthropogenic pollution. The study is based on a field approach in non-polluted natural sites with contrasting geological environments (limestone, granite, and carbonatite) and highly variable REE contents. REE concentrations in soils do not directly reflect bedrock concentrations, but depend largely on pedogenetic processes and on the mineralogy of bedrock and soil. The soils of all sites are with respect to bedrock enriched in heavy REE. The REE uptake by plants is not primarily controlled by the plant itself, but depends on the concentration and the speciation in the soil and the adsorbed soil water pool. REE uptake by plant roots are linked with those of Fe. Roots absorb preferentially the light REE. Before translocation, REE are retained by the Casparian strip leading to much lower concentrations in the aerial parts. The transport of the REE within the xylem is associated with the general nutrient flux.
TL;DR: The relationship between psoriasis and increased cancer risk is debated and research is still needed to establish a cause and effect relationship.
Abstract: The relationship between psoriasis and increased cancer risk is debated.
The aim of this study was to evaluate if there is an increase in the background risk of cancer in psoriasis patients compared with the general population.
A systematic literature search was performed on PubMed, Embase and Cochrane databases, using the keywords ‘Psoriasis [Majr] AND Neoplasms’, from 1980 to January 2012. Meta-analysis was performed based on observational studies showing consistency in cancer risk assessment methods.
Of the 1080 articles retrieved, 37 references were selected. There may be an increased risk of some solid cancers in psoriasis: respiratory tract cancer [standardized incidence ratio (SIR) = 1.52, 95% confidence interval (CI) 1.35–1.71], upper aerodigestive tract cancer (SIR = 3.05, 95% CI 1.74–5.32), urinary tract cancer (SIR = 1.31, 95% CI 1.11–1.55) and liver cancer (SIR = 1.90, 95% CI 1.48–2.44). The risk of non-Hodgkin lymphoma appears slightly increased in psoriasis (SIR = 1.40, 95% CI 1.06–1.86). Psoriasis patients have an increased risk of squamous cell carcinoma (SIR = 5.3, 95% CI 2.63–10.71) and basal cell carcinoma (SIR = 2.00, 95% CI 1.83–2.20), whereas the risk of melanoma is not increased.
There was a large heterogeneity in studies assessing cancer risk in psoriasis preventing from including all studies in meta-analysis.
This systematic literature review shows a small increased risk of some solid cancers in psoriasis, especially those linked to alcohol drinking and cigarette smoking. A higher risk of non-melanoma skin cancers, especially squamous cell carcinoma, is shown, mainly due to previous exposure to 8-methoxypsoralen-ultraviolet-A (PUVA), ciclosporin and possibly methotrexate.
TL;DR: MESSENGER neutron data reported by Lawrence et al. now confirm that the primary component of radar-reflective material at Mercury's north pole is water ice, and spacecraft data and a thermal model show that water ice and organic volatiles are present at Mercury’s north pole.
Abstract: Measurements by the Neutron Spectrometer on the MErcury Surface, Space ENvironment, GEochemistry, and Ranging (MESSENGER) spacecraft show decreases in the flux of epithermal and fast neutrons from Mercury’s north polar region that are consistent with the presence of water ice in permanently shadowed regions. The neutron data indicate that Mercury’s radar-bright polar deposits contain, on average, a hydrogen-rich layer more than tens of centimeters thick beneath a surficial layer 10 to 30 cm thick that is less rich in hydrogen. Combined neutron and radar data are best matched if the buried layer consists of nearly pure water ice. The upper layer contains less than 25 weight % water-equivalent hydrogen. The total mass of water at Mercury’s poles is inferred to be 2 × 1016 to 1018 grams and is consistent with delivery by comets or volatile-rich asteroids.
TL;DR: The best choice for serodiagnosis of the generalised forms of toxocariasis, visceral larva migrans (VLM) or covert toxocaral infections, relies upon the initial use of TES-ELISA, after which any positive result should subsequently be tested by Western blotting (WB).
National Institutes of Health1, French Institute of Health and Medical Research2, Paul Sabatier University3, University College London4, deCODE genetics5, VU University Amsterdam6, University of Tübingen7, German Center for Neurodegenerative Diseases8, Cardiff University9, University of Turku10, University of Oulu11
TL;DR: The results suggest that although GWASs are a useful tool in identifying the most common variants associated with complex disease, a great deal of common variants of small effect remain to be discovered.
Abstract: Genome-wide association studies (GWASs) have been successful at identifying single-nucleotide polymorphisms (SNPs) highly associated with common traits; however, a great deal of the heritable variation associated with common traits remains unaccounted for within the genome. Genome-wide complex trait analysis (GCTA) is a statistical method that applies a linear mixed model to estimate phenotypic variance of complex traits explained by genome-wide SNPs, including those not associated with the trait in a GWAS. We applied GCTA to 8 cohorts containing 7096 case and 19 455 control individuals of European ancestry in order to examine the missing heritability present in Parkinson's disease (PD). We meta-analyzed our initial results to produce robust heritability estimates for PD types across cohorts. Our results identify 27% (95% CI 17-38, P = 8.08E - 08) phenotypic variance associated with all types of PD, 15% (95% CI -0.2 to 33, P = 0.09) phenotypic variance associated with early-onset PD and 31% (95% CI 17-44, P = 1.34E - 05) phenotypic variance associated with late-onset PD. This is a substantial increase from the genetic variance identified by top GWAS hits alone (between 3 and 5%) and indicates there are substantially more risk loci to be identified. Our results suggest that although GWASs are a useful tool in identifying the most common variants associated with complex disease, a great deal of common variants of small effect remain to be discovered.
Johns Hopkins University School of Medicine1, Johns Hopkins University2, National Institutes of Health3, Casa Sollievo della Sofferenza4, Harvard University5, University of California, San Francisco6, Imperial College London7, Paul Sabatier University8, Cornell University9, Systems Research Institute10, University of Cambridge11, Anschutz Medical Campus12, Minia University13
TL;DR: IL-28B and HLA class II are independently associated with spontaneous resolution of HCV infection, and SNPs marking IL-28 B and DQB1*03:01 may explain approximately 15% of spontaneous resolution in persons of European and African ancestry.
Abstract: Background: hepatitis C virus (HCV) infections occur worldwide and either spontaneously resolve or persist and markedly increase the person's lifetime risk for cirrhosis and hepatocellular carcinoma. Although HCV persistence occurs more often in persons of African ancestry and persons with genetic variants near interleukin-28B (IL-28B), the genetic basis is not well-understood. Objective: to evaluate the host genetic basis for spontaneous resolution of HCV infection. Design: 2-stage, genome-wide association study. Setting: 13 international multicenter study sites. Patients: 919 persons with serum HCV antibodies but no HCV RNA (spontaneous resolution) and 1482 persons with serum HCV antibodies and HCV RNA (persistence). Measurements: frequencies of 792 721 single nucleotide polymorphisms (SNPs). Results: differences in allele frequencies between persons with spontaneous resolution and persistence were identified on chromosomes 19q13.13 and 6p21.32. On chromosome 19, allele frequency differences localized near IL-28B and included rs12979860 (overall per-allele OR, 0.45; P = 2.17 × 10?30) and 10 additional SNPs spanning 55 000 base pairs. On chromosome 6, allele frequency differences localized near genes for HLA class II and included rs4273729 (overall per-allele OR, 0.59; P = 1.71 × 10?16) near DQB1*03:01 and an additional 116 SNPs spanning 1 090 000 base pairs. The associations in chromosomes 19 and 6 were independent and additive and explain an estimated 14.9% (95% CI, 8.5% to 22.6%) and 15.8% (CI, 4.4% to 31.0%) of the variation in HCV resolution in persons of European and African ancestry, respectively. Replication of the chromosome 6 SNP, rs4272729, in an additional 745 persons confirmed the findings (P = 0.015). Limitation: epigenetic effects were not studied. Conclusion: IL-28B and HLA class II are independently associated with spontaneous resolution of HCV infection, and SNPs marking IL-28B and DQB1*03:01 may explain approximately 15% of spontaneous resolution of HCV infection
TL;DR: Partial inhibition of adipose tissue lipolysis does not increase fat mass but improves glucose metabolism and insulin sensitivity through modulation of fatty acid turnover and induction of fat cell de novo lipogenesis.
Abstract: When energy is needed, white adipose tissue (WAT) provides fatty acids (FAs) for use in peripheral tissues via stimulation of fat cell lipolysis. FAs have been postulated to play a critical role in the development of obesity-induced insulin resistance, a major risk factor for diabetes and cardiovascular disease. However, whether and how chronic inhibition of fat mobilization from WAT modulates insulin sensitivity remains elusive. Hormone-sensitive lipase (HSL) participates in the breakdown of WAT triacylglycerol into FAs. HSL haploinsufficiency and treatment with a HSL inhibitor resulted in improvement of insulin tolerance without impact on body weight, fat mass, and WAT inflammation in high-fat-diet-fed mice. In vivo palmitate turnover analysis revealed that blunted lipolytic capacity is associated with diminution in FA uptake and storage in peripheral tissues of obese HSL haploinsufficient mice. The reduction in FA turnover was accompanied by an improvement of glucose metabolism with a shift in respiratory quotient, increase of glucose uptake in WAT and skeletal muscle, and enhancement of de novo lipogenesis and insulin signalling in liver. In human adipocytes, HSL gene silencing led to improved insulin-stimulated glucose uptake, resulting in increased de novo lipogenesis and activation of cognate gene expression. In clinical studies, WAT lipolytic rate was positively and negatively correlated with indexes of insulin resistance and WAT de novo lipogenesis gene expression, respectively. In obese individuals, chronic inhibition of lipolysis resulted in induction of WAT de novo lipogenesis gene expression. Thus, reduction in WAT lipolysis reshapes FA fluxes without increase of fat mass and improves glucose metabolism through cell-autonomous induction of fat cell de novo lipogenesis, which contributes to improved insulin sensitivity.
TL;DR: In this article, the authors investigated whether neonatal infections are associated with a higher risk of adverse neurodevelopment at 5 years of age in a population-based cohort of very preterm children.
Abstract: OBJECTIVE: To determine whether neonatal infections are associated with a higher risk of adverse neurodevelopment at 5 years of age in a population-based cohort of very preterm children. METHODS: We included all live births between 22 and 32 weeks of gestation, from 9 regions in France, in 1997 (EPIPAGE study). Of the 2665 live births, 2277 were eligible for a follow-up evaluation at 5 years of age: 1769 had a medical examination and 1495 underwent cognitive assessment. Cerebral palsy and cognitive impairment were studied as a function of early-onset sepsis (EOS) and late-onset sepsis (LOS), after adjustment for potential confounding factors, in multivariate logistic regression models. RESULTS: A total of 139 (5%) of the 2665 live births included in the study presented with EOS alone (without associated LOS), 752 (28%) had LOS alone (without associated EOS), and 64 (2%) displayed both EOS and LOS. At 5 years of age, the frequency of cerebral palsy was 9% (157 of 1769) and that of cognitive impairment was 12% (177 of 1495). The frequency of cerebral palsy was higher in infants with isolated EOS (odds ratio [OR]: 1.70 [95% confidence interval (CI): 0.84-3.45]) or isolated LOS (OR: 1.71 [95% CI: 1.14-2.56]) than in uninfected infants, and this risk was even higher in cases of combined EOS and LOS (OR: 2.33 [95% CI: 1.02-5.33]). There was no association between neonatal infection and cognitive impairment. CONCLUSIONS: Neonatal infections in these very preterm infants were associated with a higher risk of cerebral palsy at the age of 5 years, particularly in infants presenting with both EOS and LOS.
TL;DR: The quantum Cramer--Rao bound is calculated for the sensitivity with which one or several parameters, encoded in a general single-mode Gaussian state, can be estimated, including in particular the interesting case of mixed Gaussian states.
Abstract: We calculate the quantum Cramer--Rao bound for the sensitivity with which one or several parameters, encoded in a general single-mode Gaussian state, can be estimated. This includes in particular the interesting case of mixed Gaussian states. We apply the formula to the problems of estimating phase, purity, loss, amplitude, and squeezing. In the case of the simultaneous measurement of several parameters, we provide the full quantum Fisher information matrix. Our results unify previously known partial results, and constitute a complete solution to the problem of knowing the best possible sensitivity of measurements based on a single-mode Gaussian state.
TL;DR: Overall, the results suggest that cavitation resistance is a causal factor of tree mortality under extreme drought conditions.