Showing papers by "University of Rennes published in 2018"

Prospects for Observing and Localizing Gravitational-Wave Transients with Advanced LIGO, Advanced Virgo and KAGRA

Abstract: We present possible observing scenarios for the Advanced LIGO, Advanced Virgo and KAGRA gravitational-wave detectors over the next decade, with the intention of providing information to the astronomy community to facilitate planning for multi-messenger astronomy with gravitational waves. We estimate the sensitivity of the network to transient gravitational-wave signals, and study the capability of the network to determine the sky location of the source. We report our findings for gravitational-wave transients, with particular focus on gravitational-wave signals from the inspiral of binary neutron star systems, which are the most promising targets for multi-messenger astronomy. The ability to localize the sources of the detected signals depends on the geographical distribution of the detectors and their relative sensitivity, and 90% credible regions can be as large as thousands of square degrees when only two sensitive detectors are operational. Determining the sky position of a significant fraction of detected signals to areas of 5– 20 deg2 requires at least three detectors of sensitivity within a factor of ∼2 of each other and with a broad frequency bandwidth. When all detectors, including KAGRA and the third LIGO detector in India, reach design sensitivity, a significant fraction of gravitational-wave signals will be localized to a few square degrees by gravitational-wave observations alone.

Standardization of left atrial, right ventricular, and right atrial deformation imaging using two-dimensional speckle tracking echocardiography: a consensus document of the EACVI/ASE/Industry Task Force to standardize deformation imaging.

Abstract: The EACVI/ASE/Industry Task Force to standardize deformation imaging prepared this consensus document to standardize definitions and techniques for using two-dimensional (2D) speckle tracking echocardiography (STE) to assess left atrial, right ventricular, and right atrial myocardial deformation. This document is intended for both the technical engineering community and the clinical community at large to provide guidance on selecting the functional parameters to measure and how to measure them using 2D STE.This document aims to represent a significant step forward in the collaboration between the scientific societies and the industry since technical specifications of the software packages designed to post-process echocardiographic datasets have been agreed and shared before their actual development. Hopefully, this will lead to more clinically oriented software packages which will be better tailored to clinical needs and will allow industry to save time and resources in their development.

Gaia Data Release 2. Observations of solar system objects

Abstract: Context. The Gaia spacecraft of the European Space Agency (ESA) has been securing observations of solar system objects (SSOs) since the beginning of its operations. Data Release 2 (DR2) contains the observations of a selected sample of 14,099 SSOs. These asteroids have been already identified and have been numbered by the Minor Planet Center repository. Positions are provided for each Gaia observation at CCD level. As additional information, complementary to astrometry, the apparent brightness of SSOs in the unfiltered G band is also provided for selected observations.Aims. We explain the processing of SSO data, and describe the criteria we used to select the sample published in Gaia DR2. We then explore the data set to assess its quality.Methods. To exploit the main data product for the solar system in Gaia DR2, which is the epoch astrometry of asteroids, it is necessary to take into account the unusual properties of the uncertainty, as the position information is nearly one-dimensional. When this aspect is handled appropriately, an orbit fit can be obtained with post-fit residuals that are overall consistent with the a-priori error model that was used to define individual values of the astrometric uncertainty. The role of both random and systematic errors is described. The distribution of residuals allowed us to identify possible contaminants in the data set (such as stars). Photometry in the G band was compared to computed values from reference asteroid shapes and to the flux registered at the corresponding epochs by the red and blue photometers (RP and BP).Results. The overall astrometric performance is close to the expectations, with an optimal range of brightness G ~ 12 − 17. In this range, the typical transit-level accuracy is well below 1 mas. For fainter asteroids, the growing photon noise deteriorates the performance. Asteroids brighter than G ~ 12 are affected by a lower performance of the processing of their signals. The dramatic improvement brought by Gaia DR2 astrometry of SSOs is demonstrated by comparisons to the archive data and by preliminary tests on the detection of subtle non-gravitational effects.

Hybrid Dion–Jacobson 2D Lead Iodide Perovskites

Abstract: The three-dimensional hybrid organic–inorganic perovskites have shown huge potential for use in solar cells and other optoelectronic devices. Although these materials are under intense investigation, derivative materials with lower dimensionality are emerging, offering higher tunability of physical properties and new capabilities. Here, we present two new series of hybrid two-dimensional (2D) perovskites that adopt the Dion–Jacobson (DJ) structure type, which are the first complete homologous series reported in halide perovskite chemistry. Lead iodide DJ perovskites adopt a general formula A′An–1PbnI3n+1 (A′ = 3-(aminomethyl)piperidinium (3AMP) or 4-(aminomethyl)piperidinium (4AMP), A = methylammonium (MA)). These materials have layered structures where the stacking of inorganic layers is unique as they lay exactly on top of another. With a slightly different position of the functional group in the templating cation 3AMP and 4AMP, the as-formed DJ perovskites show different optical properties, with the 3A...

Hydrocortisone plus Fludrocortisone for Adults with Septic Shock

Abstract: Background Septic shock is characterized by dysregulation of the host response to infection, with circulatory, cellular, and metabolic abnormalities. We hypothesized that therapy with hydrocortisone plus fludrocortisone or with drotrecogin alfa (activated), which can modulate the host response, would improve the clinical outcomes of patients with septic shock. Methods In this multicenter, double-blind, randomized trial with a 2-by-2 factorial design, we evaluated the effect of hydrocortisone-plus-fludrocortisone therapy, drotrecogin alfa (activated), the combination of the three drugs, or their respective placebos. The primary outcome was 90-day all-cause mortality. Secondary outcomes included mortality at intensive care unit (ICU) discharge and hospital discharge and at day 28 and day 180 and the number of days alive and free of vasopressors, mechanical ventilation, or organ failure. After drotrecogin alfa (activated) was withdrawn from the market, the trial continued with a two-group parallel d...

Sensitive tumour detection and classification using plasma cell-free DNA methylomes

Abstract: The use of liquid biopsies for cancer detection and management is rapidly gaining prominence1. Current methods for the detection of circulating tumour DNA involve sequencing somatic mutations using cell-free DNA, but the sensitivity of these methods may be low among patients with early-stage cancer given the limited number of recurrent mutations2–5. By contrast, large-scale epigenetic alterations—which are tissue- and cancer-type specific—are not similarly constrained6 and therefore potentially have greater ability to detect and classify cancers in patients with early-stage disease. Here we develop a sensitive, immunoprecipitation-based protocol to analyse the methylome of small quantities of circulating cell-free DNA, and demonstrate the ability to detect large-scale DNA methylation changes that are enriched for tumour-specific patterns. We also demonstrate robust performance in cancer detection and classification across an extensive collection of plasma samples from several tumour types. This work sets the stage to establish biomarkers for the minimally invasive detection, interception and classification of early-stage cancers based on plasma cell-free DNA methylation patterns. An immunoprecipitation-based protocol is developed to analyse DNA methylation in small quantities of circulating cell-free DNA, and can detect and classify cancers in plasma samples from several tumour types.

Photoredox Catalysis for Building C-C Bonds from C(sp2)-H Bonds.

Abstract: Transition metal-catalyzed C–H bond functionalizations have been the focus of intensive research over the last decades for the formation of C–C bonds from unfunctionalized arenes, heteroarenes, alkenes These direct transformations provide new approaches in synthesis with high atom- and step-economy compared to the traditional catalytic cross-coupling reactions However, such methods still suffer from several limitations including functional group tolerance and the lack of regioselectivity In addition, they often require harsh reaction conditions and some of them need the use of strong oxidant, in a stoichiometric amount, avoiding these processes to be truly eco-friendly The use of photoredox catalysis has contributed to a significant expansion of the scope of C(sp2)–H bond functionalizations which include the direct arylations, (perfluoro)alkylations, acylations, and even cyanations Most of these transformations involve the photochemical induced generation of a radical followed by its regioselective a

Scaling law for excitons in 2D perovskite quantum wells.

Abstract: Ruddlesden–Popper halide perovskites are 2D solution-processed quantum wells with a general formula A2A’n-1M n X3n+1, where optoelectronic properties can be tuned by varying the perovskite layer thickness (n-value), and have recently emerged as efficient semiconductors with technologically relevant stability. However, fundamental questions concerning the nature of optical resonances (excitons or free carriers) and the exciton reduced mass, and their scaling with quantum well thickness, which are critical for designing efficient optoelectronic devices, remain unresolved. Here, using optical spectroscopy and 60-Tesla magneto-absorption supported by modeling, we unambiguously demonstrate that the optical resonances arise from tightly bound excitons with both exciton reduced masses and binding energies decreasing, respectively, from 0.221 m0 to 0.186 m0 and from 470 meV to 125 meV with increasing thickness from n equals 1 to 5. Based on this study we propose a general scaling law to determine the binding energy of excitons in perovskite quantum wells of any layer thickness. Hybrid 2D layered perovskites are solution-processed quantum wells whose optoelectronic properties are tunable by varying the thickness of the inorganic slab. Here Blancon et al. work out a general behavior for dependence of the excitonic properties in layered 2D perovskites.

Anharmonicity and Disorder in the Black Phases of Cesium Lead Iodide Used for Stable Inorganic Perovskite Solar Cells

Abstract: Hybrid organic–inorganic perovskites emerged as a new generation of absorber materials for high-efficiency low-cost solar cells in 2009. Very recently, fully inorganic perovskite quantum dots also led to promising efficiencies, making them a potentially stable and efficient alternative to their hybrid cousins. Currently, the record efficiency is obtained with CsPbI3, whose crystallographical characterization is still limited. Here, we show through high-resolution in situ synchrotron XRD measurements that CsPbI3 can be undercooled below its transition temperature and temporarily maintained in its perovskite structure down to room temperature, stabilizing a metastable perovskite polytype (black γ-phase) crucial for photovoltaic applications. Our analysis of the structural phase transitions reveals a highly anisotropic evolution of the individual lattice parameters versus temperature. Structural, vibrational, and electronic properties of all the experimentally observed black phases are further inspected base...

Crop pests and predators exhibit inconsistent responses to surrounding landscape composition

Abstract: The idea that noncrop habitat enhances pest control and represents a win-win opportunity to conserve biodiversity and bolster yields has emerged as an agroecological paradigm. However, while noncrop habitat in landscapes surrounding farms sometimes benefits pest predators, natural enemy responses remain heterogeneous across studies and effects on pests are inconclusive. The observed heterogeneity in species responses to noncrop habitat may be biological in origin or could result from variation in how habitat and biocontrol are measured. Here, we use a pest-control database encompassing 132 studies and 6,759 sites worldwide to model natural enemy and pest abundances, predation rates, and crop damage as a function of landscape composition. Our results showed that although landscape composition explained significant variation within studies, pest and enemy abundances, predation rates, crop damage, and yields each exhibited different responses across studies, sometimes increasing and sometimes decreasing in landscapes with more noncrop habitat but overall showing no consistent trend. Thus, models that used landscape-composition variables to predict pest-control dynamics demonstrated little potential to explain variation across studies, though prediction did improve when comparing studies with similar crop and landscape features. Overall, our work shows that surrounding noncrop habitat does not consistently improve pest management, meaning habitat conservation may bolster production in some systems and depress yields in others. Future efforts to develop tools that inform farmers when habitat conservation truly represents a win-win would benefit from increased understanding of how landscape effects are modulated by local farm management and the biology of pests and their enemies.

Gaia Data Release 2 - First stellar parameters from Apsis

Abstract: The second Gaia data release (Gaia DR2) contains, beyond the astrometry, three-band photometry for 1.38 billion sources. One band is the G band, the other two were obtained by integrating the Gaia prism spectra (BP and RP). We have used these three broad photometric bands to infer stellar effective temperatures, T eff , for all sources brighter than G = 17 mag with T eff in the range 3000–10 000 K (some 161 million sources). Using in addition the parallaxes, we infer the line-of-sight extinction, A G , and the reddening, E (BP − RP), for 88 million sources. Together with a bolometric correction we derive luminosity and radius for 77 million sources. These quantities as well as their estimated uncertainties are part of Gaia DR2. Here we describe the procedures by which these quantities were obtained, including the underlying assumptions, comparison with literature estimates, and the limitations of our results. Typical accuracies are of order 324 K (T eff ), 0.46 mag (A G ), 0.23 mag (E (BP − RP)), 15% (luminosity), and 10% (radius). Being based on only a small number of observable quantities and limited training data, our results are necessarily subject to some extreme assumptions that can lead to strong systematics in some cases (not included in the aforementioned accuracy estimates). One aspect is the non-negativity contraint of our estimates, in particular extinction, which we discuss. Yet in several regions of parameter space our results show very good performance, for example for red clump stars and solar analogues. Large uncertainties render the extinctions less useful at the individual star level, but they show good performance for ensemble estimates. We identify regimes in which our parameters should and should not be used and we define a “clean” sample. Despite the limitations, this is the largest catalogue of uniformly-inferred stellar parameters to date. More precise and detailed astrophysical parameters based on the full BP/RP spectrophotometry are planned as part of the third Gaia data release.

Global models underestimate large decadal declining and rising water storage trends relative to GRACE satellite data

Abstract: Assessing reliability of global models is critical because of increasing reliance on these models to address past and projected future climate and human stresses on global water resources. Here, we evaluate model reliability based on a comprehensive comparison of decadal trends (2002-2014) in land water storage from seven global models (WGHM, PCR-GLOBWB, GLDAS NOAH, MOSAIC, VIC, CLM, and CLSM) to trends from three Gravity Recovery and Climate Experiment (GRACE) satellite solutions in 186 river basins (∼60% of global land area). Medians of modeled basin water storage trends greatly underestimate GRACE-derived large decreasing (≤-0.5 km3/y) and increasing (≥0.5 km3/y) trends. Decreasing trends from GRACE are mostly related to human use (irrigation) and climate variations, whereas increasing trends reflect climate variations. For example, in the Amazon, GRACE estimates a large increasing trend of ∼43 km3/y, whereas most models estimate decreasing trends (-71 to 11 km3/y). Land water storage trends, summed over all basins, are positive for GRACE (∼71-82 km3/y) but negative for models (-450 to -12 km3/y), contributing opposing trends to global mean sea level change. Impacts of climate forcing on decadal land water storage trends exceed those of modeled human intervention by about a factor of 2. The model-GRACE comparison highlights potential areas of future model development, particularly simulated water storage. The inability of models to capture large decadal water storage trends based on GRACE indicates that model projections of climate and human-induced water storage changes may be underestimated.

A Placebo-Controlled Trial of Bezafibrate in Primary Biliary Cholangitis.

Abstract: Background : Patients with primary biliary cholangitis who have an inadequate response to therapy with ursodeoxycholic acid are at high risk for disease progression. Fibrates, which are agonists of peroxisome proliferator–activated receptors, in combination with ursodeoxycholic acid, have shown potential benefit in patients with this condition. Methods : In this 24-month, double-blind, placebo-controlled, phase 3 trial, we randomly assigned 100 patients who had had an inadequate response to ursodeoxycholic acid according to the Paris 2 criteria to receive bezafibrate at a daily dose of 400 mg (50 patients), or placebo (50 patients), in addition to continued treatment with ursodeoxycholic acid. The primary outcome was a complete biochemical response, which was defined as normal levels of total bilirubin, alkaline phosphatase, aminotransferases, and albumin, as well as a normal prothrombin index (a derived measure of prothrombin time), at 24 months. Results : The primary outcome occurred in 31% of the patients assigned to bezafibrate and in 0% assigned to placebo (difference, 31 percentage points; 95% confidence interval, 10 to 50; P<0.001). Normal levels of alkaline phosphatase were observed in 67% of the patients in the bezafibrate group and in 2% in the placebo group. Results regarding changes in pruritus, fatigue, and noninvasive measures of liver fibrosis, including liver stiffness and Enhanced Liver Fibrosis score, were consistent with the results of the primary outcome. Two patients in each group had complications from end-stage liver disease. The creatinine level increased 5% from baseline in the bezafibrate group and decreased 3% in the placebo group. Myalgia occurred in 20% of the patients in the bezafibrate group and in 10% in the placebo group. Conclusions : Among patients with primary biliary cholangitis who had had an inadequate response to ursodeoxycholic acid alone, treatment with bezafibrate in addition to ursodeoxycholic acid resulted in a rate of complete biochemical response that was significantly higher than the rate with placebo and ursodeoxycholic acid therapy. (Funded by Programme Hospitalier de Recherche Clinique and Arrow Generiques; BEZURSO ClinicalTrials.gov number, NCT01654731.)

Global sea-level budget 1993 - present

Abstract: Global mean sea level is an integral of changes occurring in the climate system in response to unforced climate variability as well as natural and anthropogenic forcing factors. Its temporal evolution allows detecting changes (e.g., acceleration) in one or more components. Study of the sea level budget provides constraints on missing or poorly known contributions, such as the unsurveyed deep ocean or the still uncertain land water component. In the context of the World Climate Research Programme Grand Challenge entitled “Regional Sea Level and Coastal Impacts”, an international effort involving the sea level community worldwide has been recently initiated with the objective of assessing the various data sets used to estimate components of the sea level budget during the altimetry era (1993 to present). These data sets are based on the combination of a broad range of space-based and in situ observations, model estimates and algorithms. Evaluating their quality, quantifying uncertainties and identifying sources of discrepancies between component estimates is extremely useful for various applications in climate research. This effort involves several tens of scientists from about fifty research teams/institutions worldwide (www.wcrp-climate.org/grand-challenges/gc-sea- level). The results presented in this paper are a synthesis of the first assessment performed during 2017-2018. We present estimates of the altimetry-based global mean sea level (average rate of 3.1 +/- 0.3 mm/yr and acceleration of 0.1 mm/yr2 over 1993-present), as well as of the different components of the sea level budget (http://doi.org/10.17882/54854). We further examine closure of the sea level budget, comparing the observed global mean sea level with the sum of components. Ocean thermal expansion, glaciers, Greenland and Antarctica contribute by 42%, 21%, 15% and 8% to the global mean sea level over the 1993-present. We also study the sea level budget over 2005-present, using GRACE-based ocean mass estimates instead of sum of individual mass components. Results show closure of the sea level budget within 0.3 mm/yr. Substantial uncertainty remains for the land water storage component, as shown in examining individual mass contributions to sea level.

Structural Diversity in White-Light-Emitting Hybrid Lead Bromide Perovskites

Abstract: Hybrid organic–inorganic halide perovskites are under intense investigations because of their astounding physical properties and promises for optoelectronics. Lead bromide and chloride perovskites exhibit intrinsic white-light emission believed to arise from self-trapped excitons (STEs). Here, we report a series of new structurally diverse hybrid lead bromide perovskites that have broad-band emission at room temperature. They feature Pb/Br structures which vary from 1D face-sharing structures to 3D corner- and edge-sharing structures. Through single-crystal X-ray diffraction and low-frequency Raman spectroscopy, we have identified the local distortion level of the octahedral environments of Pb2+ within the structures. The band gaps of these compounds range from 2.92 to 3.50 eV, following the trend of “corner-sharing < edge-sharing < face-sharing”. Density functional theory calculations suggest that the electronic structure is highly dependent on the connectivity mode of the PbBr6 octahedra, where the edge...

Magnetite and Green Rust: Synthesis, Properties, and Environmental Applications of Mixed-Valent Iron Minerals

Abstract: Mixed-valent iron [Fe(II)-Fe(III)] minerals such as magnetite and green rust have received a significant amount of attention over recent decades, especially in the environmental sciences. These mineral phases are intrinsic and essential parts of biogeochemical cycling of metals and organic carbon and play an important role regarding the mobility, toxicity, and redox transformation of organic and inorganic pollutants. The formation pathways, mineral properties, and applications of magnetite and green rust are currently active areas of research in geochemistry, environmental mineralogy, geomicrobiology, material sciences, environmental engineering, and environmental remediation. These aspects ultimately dictate the reactivity of magnetite and green rust in the environment, which has important consequences for the application of these mineral phases, for example in remediation strategies. In this review we discuss the properties, occurrence, formation by biotic as well as abiotic pathways, characterization t...

Chromosome-scale assemblies of plant genomes using nanopore long reads and optical maps

Abstract: Plant genomes are often characterized by a high level of repetitiveness and polyploid nature. Consequently, creating genome assemblies for plant genomes is challenging. The introduction of short-read technologies 10 years ago substantially increased the number of available plant genomes. Generally, these assemblies are incomplete and fragmented, and only a few are at the chromosome scale. Recently, Pacific Biosciences and Oxford Nanopore sequencing technologies were commercialized that can sequence long DNA fragments (kilobases to megabase) and, using efficient algorithms, provide high-quality assemblies in terms of contiguity and completeness of repetitive regions1–4. However, even though genome assemblies based on long reads exhibit high contig N50s (>1 Mb), these methods are still insufficient to decipher genome organization at the chromosome level. Here, we describe a strategy based on long reads (MinION or PromethION sequencers) and optical maps (Saphyr system) that can produce chromosome-level assemblies and demonstrate applicability by generating high-quality genome sequences for two new dicotyledon morphotypes, Brassica rapa Z1 (yellow sarson) and Brassica oleracea HDEM (broccoli), and one new monocotyledon, Musa schizocarpa (banana). All three assemblies show contig N50s of >5 Mb and contain scaffolds that represent entire chromosomes or chromosome arms. Assembling genomes to chromosome scale remains a challenge. Now, a study reports a strategy based on nanopore long reads and optical maps and uses it to produce high-quality chromosome-scale assemblies for the genomes of yellow sarson, broccoli and banana.

Imaging features and safety and efficacy of endovascular stroke treatment: a meta-analysis of individual patient-level data.

Abstract: Background: Evidence regarding whether imaging can be used effectively to select patients for endovascular thrombectomy (EVT) is scarce. We aimed to investigate the association between baseline imaging features and safety and efficacy of EVT in acute ischaemic stroke caused by anterior large-vessel occlusion. Methods: In this meta-analysis of individual patient-level data, the HERMES collaboration identified in PubMed seven randomised trials in endovascular stroke that compared EVT with standard medical therapy, published between Jan 1, 2010, and Oct 31, 2017. Only trials that required vessel imaging to identify patients with proximal anterior circulation ischaemic stroke and that used predominantly stent retrievers or second-generation neurothrombectomy devices in the EVT group were included. Risk of bias was assessed with the Cochrane handbook methodology. Central investigators, masked to clinical information other than stroke side, categorised baseline imaging features of ischaemic change with the Alberta Stroke Program Early CT Score (ASPECTS) or according to involvement of more than 33% of middle cerebral artery territory, and by thrombus volume, hyperdensity, and collateral status. The primary endpoint was neurological functional disability scored on the modified Rankin Scale (mRS) score at 90 days after randomisation. Safety outcomes included symptomatic intracranial haemorrhage, parenchymal haematoma type 2 within 5 days of randomisation, and mortality within 90 days. For the primary analysis, we used mixed-methods ordinal logistic regression adjusted for age, sex, National Institutes of Health Stroke Scale score at admission, intravenous alteplase, and time from onset to randomisation, and we used interaction terms to test whether imaging categorisation at baseline modifies the association between treatment and outcome. This meta-analysis was prospectively designed by the HERMES executive committee but has not been registered. Findings: Among 1764 pooled patients, 871 were allocated to the EVT group and 893 to the control group. Risk of bias was low except in the THRACE study, which used unblinded assessment of outcomes 90 days after randomisation and MRI predominantly as the primary baseline imaging tool. The overall treatment effect favoured EVT (adjusted common odds ratio [cOR] for a shift towards better outcome on the mRS 2·00, 95% CI 1·69–2·38; p<0·0001). EVT achieved better outcomes at 90 days than standard medical therapy alone across a broad range of baseline imaging categories. Mortality at 90 days (14·7% vs 17·3%, p=0·15), symptomatic intracranial haemorrhage (3·8% vs 3·5%, p=0·90), and parenchymal haematoma type 2 (5·6% vs 4·8%, p=0·52) did not differ between the EVT and control groups. No treatment effect modification by baseline imaging features was noted for mortality at 90 days and parenchymal haematoma type 2. Among patients with ASPECTS 0–4, symptomatic intracranial haemorrhage was seen in ten (19%) of 52 patients in the EVT group versus three (5%) of 66 patients in the control group (adjusted cOR 3·94, 95% CI 0·94–16·49; pinteraction=0·025), and among patients with more than 33% involvement of middle cerebral artery territory, symptomatic intracranial haemorrhage was observed in 15 (14%) of 108 patients in the EVT group versus four (4%) of 113 patients in the control group (4·17, 1·30–13·44, pinteraction=0·012). Interpretation: EVT achieves better outcomes at 90 days than standard medical therapy across a broad range of baseline imaging categories, including infarcts affecting more than 33% of middle cerebral artery territory or ASPECTS less than 6, although in these patients the risk of symptomatic intracranial haemorrhage was higher in the EVT group than the control group. This analysis provides preliminary evidence for potential use of EVT in patients with large infarcts at baseline. Funding: Medtronic.

Assessing scientists for hiring, promotion, and tenure.

Abstract: Assessment of researchers is necessary for decisions of hiring, promotion, and tenure. A burgeoning number of scientific leaders believe the current system of faculty incentives and rewards is misaligned with the needs of society and disconnected from the evidence about the causes of the reproducibility crisis and suboptimal quality of the scientific publication record. To address this issue, particularly for the clinical and life sciences, we convened a 22-member expert panel workshop in Washington, DC, in January 2017. Twenty-two academic leaders, funders, and scientists participated in the meeting. As background for the meeting, we completed a selective literature review of 22 key documents critiquing the current incentive system. From each document, we extracted how the authors perceived the problems of assessing science and scientists, the unintended consequences of maintaining the status quo for assessing scientists, and details of their proposed solutions. The resulting table was used as a seed for participant discussion. This resulted in six principles for assessing scientists and associated research and policy implications. We hope the content of this paper will serve as a basis for establishing best practices and redesigning the current approaches to assessing scientists by the many players involved in that process.

GW170817: Implications for the Stochastic Gravitational-Wave Background from Compact Binary Coalescences

Abstract: The LIGO Scientific and Virgo Collaborations have announced the event GW170817, the first detection of gravitational waves from the coalescence of two neutron stars. The merger rate of binary neutron stars estimated from this event suggests that distant, unresolvable binary neutron stars create a significant astrophysical stochastic gravitational-wave background. The binary neutron star component will add to the contribution from binary black holes, increasing the amplitude of the total astrophysical background relative to previous expectations. In the Advanced LIGO-Virgo frequency band most sensitive to stochastic backgrounds (near 25 Hz), we predict a total astrophysical background with amplitude ΩGW(f=25 Hz)=1.8 +2.7 −1.3×10−9 with 90% confidence, compared with ΩGW(f=25 Hz)=1.1 +1.2 −0.7×10−9 from binary black holes alone. Assuming the most probable rate for compact binary mergers, we find that the total background may be detectable with a signal-to-noise-ratio of 3 after 40 months of total observation time, based on the expected timeline for Advanced LIGO and Virgo to reach their design sensitivity.

Indocyanine green-incorporating nanoparticles for cancer theranostics.

Abstract: Indocyanine green (ICG) is a near-infrared dye that has been used in the clinic for retinal angiography, and defining cardiovascular and liver function for over 50 years. Recently, there has been an increasing interest in the incorporation of ICG into nanoparticles (NPs) for cancer theranostic applications. Various types of ICG-incorporated NPs have been developed and strategically functionalised to embrace multiple imaging and therapeutic techniques for cancer diagnosis and treatment. This review systematically summaries the biodistribution of various types of ICG-incorporated NPs for the first time, and discusses the principles, opportunities, limitations, and application of ICG-incorporated NPs for cancer theranostics. We believe that ICG-incorporated NPs would be a promising multifunctional theranostic platform in oncology and facilitate significant advancements in this research-active area.

Qubit allocation

Abstract: In May of 2016, IBM Research has made a quantum processor available in the cloud to the general public. The possibility of programming an actual quantum device has elicited much enthusiasm. Yet, quantum programming still lacks the compiler support that modern programming languages enjoy today. To use universal quantum computers like IBM's, programmers must design low-level circuits. In particular, they must map logical qubits into physical qubits that need to obey connectivity constraints. This task resembles the early days of programming, in which software was built in machine languages. In this paper, we formally introduce the qubit allocation problem and provide an exact solution to it. This optimal algorithm deals with the simple quantum machinery available today; however, it cannot scale up to the more complex architectures scheduled to appear. Thus, we also provide a heuristic solution to qubit allocation, which is faster than the current solutions already implemented to deal with this problem.

Why rankings of biomedical image analysis competitions should be interpreted with care

Abstract: International challenges have become the standard for validation of biomedical image analysis methods. Given their scientific impact, it is surprising that a critical analysis of common practices related to the organization of challenges has not yet been performed. In this paper, we present a comprehensive analysis of biomedical image analysis challenges conducted up to now. We demonstrate the importance of challenges and show that the lack of quality control has critical consequences. First, reproducibility and interpretation of the results is often hampered as only a fraction of relevant information is typically provided. Second, the rank of an algorithm is generally not robust to a number of variables such as the test data used for validation, the ranking scheme applied and the observers that make the reference annotations. To overcome these problems, we recommend best practice guidelines and define open research questions to be addressed in the future.

Separate and combined associations of obesity and metabolic health with coronary heart disease: a pan-European case-cohort analysis.

Abstract: EPIC-CVD has been supported by the European Union Framework 7 (HEALTH-F2-2012-279233), the European Research Council (268834), the UK Medical Research Council (G0800270 and MR/L003120/1), the British Heart Foundation (SP/09/002 and RG/08/014 and RG13/13/30194), and the UK National Institute of Health Research. EPIC Asturias was also supported by the Regional Government of Asturias. EPIC-Greece is also supported by the Hellenic Health Foundation. EPIC- Heidelberg was also supported by the German Cancer Aid, German Cancer Research Centre, German Federal Ministry of Education and Research. EPIC-Oxford was also supported by the UK Medical Research Council (MR/M012190/1) and Cancer Research UK (570/A16491). EPIC-Ragusa was also supported by the Sicilian Government, AIRE ONLUS Ragusa, and AVIS Ragusa. EPIC-Turin was supported also by the Compagnia di San Paolo and the Human Genetics Foundation-Torino (HuGeF).

Advances in Surface Passivation of Nanoscale Zerovalent Iron: A Critical Review

Abstract: Nanoscale zerovalent iron (NZVI) is one of the most extensively studied nanomaterials in the fields of wastewater treatment and remediation of soil and groundwater. However, rapid oxidative transfo...

Critical Role of Interface and Crystallinity on the Performance and Photostability of Perovskite Solar Cell on Nickel Oxide

Abstract: Hybrid perovskites are on a trajectory toward realizing the most efficient single-junction, solution-processed photovoltaic devices. However, a critical issue is the limited understanding of the correlation between the degree of crystallinity and the emergent perovskite/hole (or electron) transport layer on device performance and photostability. Here, the controlled growth of hybrid perovskites on nickel oxide (NiO) is shown, resulting in the formation of thin films with enhanced crystallinity with characteristic peak width and splitting reminiscent of the tetragonal phase in single crystals. Photophysical and interface sensitive measurements reveal a reduced trap density at the perovskite/NiO interface in comparison with perovskites grown on poly(3,4-ethylene dioxy thiophene) polystyrene sulfonate. Photovoltaic cells exhibit a high open circuit voltage (1.12 V), indicating a near-ideal energy band alignment. Moreover, photostability of photovoltaic devices up to 10-Suns is observed, which is a direct result of the superior crystallinity of perovskite thin films on NiO. These results elucidate the critical role of the quality of the perovskite/hole transport layer interface in rendering high-performance and photostable optoelectronic devices.