723 research outputs found
Assimilation of passive microwave AMSR-2 satellite observations in a snowpack evolution model over northeastern Canada
Over northeastern Canada, the amount of water stored in a
snowpack, estimated by its snow water equivalent (SWE) amount, is a key
variable for hydrological applications. The limited number of weather
stations driving snowpack models over large and remote northern areas
generates great uncertainty in SWE evolution. A data assimilation (DA) scheme
was developed to improve SWE estimates by updating meteorological forcing
data and snowpack states with passive microwave (PMW) satellite observations
and without using any surface-based data. In this DA experiment, a particle
filter with a Sequential Importance
Resampling algorithm (SIR) was applied and an
inflation technique of the observation error matrix was developed to avoid
ensemble degeneracy. Advanced Microwave Scanning Radiometer 2 (AMSR-2)
brightness temperature (TB) observations were assimilated into a
chain of models composed of the Crocus multilayer snowpack model and
radiative transfer models. The microwave snow emission model (Dense Media
Radiative Transfer – Multi-Layer model, DMRT-ML), the vegetation transmissivity
model (ω-τopt), and atmospheric and soil radiative
transfer models were calibrated to simulate the contributions from the
snowpack, the vegetation, and the soil, respectively, at the top of the
atmosphere. DA experiments were performed for 12 stations where daily
continuous SWE measurements were acquired over 4 winters (2012–2016). Best
SWE estimates are obtained with the assimilation of the TBs at
11, 19, and 37 GHz in vertical polarizations. The overall SWE bias is reduced
by 68 % compared to the original SWE simulations, from 23.7 kg m−2
without assimilation to 7.5 kg m−2 with the assimilation of the three
frequencies. The overall SWE relative percentage of error (RPE) is 14.1 %
(19 % without assimilation) for sites with a fraction of forest cover
below 75 %, which is in the range of accuracy needed for hydrological
applications. This research opens the way for global applications to improve
SWE estimates over large and remote areas, even when vegetation contributions
are up to 50 % of the PMW signal.</p
Risk aversion and willingness to pay for water quality: The case of non-farm rural residents
Stated choice experiments are used to investigate the economic valuation of rural residents living in the province of Quebec for water quality improvements. In Quebec, rural residents played an important role in the setting of stricter environmental regulations. Unlike most stated choice experiments about the valuation of improvements in water quality, this study explicitly accounts for risk in the design and analysis of choice experiments. Risk in phosphorus and coliform reductions is introduced through a three-point uniform distribution in the choice sets. The results show greater support for constant absolute risk aversion preferences than for constant relative risk aversion. Rural residents value coliform and phosphorus reductions and the more educated ones are particularly willing to see the government tax farmers and taxpayers to secure such reductions. As the science improves and risk in water quality outcomes decrease and as the political weight of non-farm rural residents increase, it should be easier for governments to replace voluntary cost-share programs by polluter-payer programs
Effect of Oral Iron Repletion on Exercise Capacity in Patients With Heart Failure With Reduced Ejection Fraction and Iron Deficiency: The IRONOUT HF Randomized Clinical Trial.
Importance: Iron deficiency is present in approximately 50% of patients with heart failure with reduced left ventricular ejection fraction (HFrEF) and is an independent predictor of reduced functional capacity and mortality. However, the efficacy of inexpensive readily available oral iron supplementation in heart failure is unknown.
Objective: To test whether therapy with oral iron improves peak exercise capacity in patients with HFrEF and iron deficiency.
Design, Setting, and Participants: Phase 2, double-blind, placebo-controlled randomized clinical trial of patients with HFrEF (
Interventions: Oral iron polysaccharide (n = 111) or placebo (n = 114), 150 mg twice daily for 16 weeks.
Main Outcomes and Measures: The primary end point was a change in peak oxygen uptake (V̇o2) from baseline to 16 weeks. Secondary end points were change in 6-minute walk distance, plasma N-terminal pro-B-type natriuretic peptide (NT-proBNP) levels, and health status as assessed by Kansas City Cardiomyopathy Questionnaire (KCCQ, range 0-100, higher scores reflect better quality of life).
Results: Among 225 randomized participants (median age, 63 years; 36% women) 203 completed the study. The median baseline peak V̇o2 was 1196 mL/min (interquartile range [IQR], 887-1448 mL/min) in the oral iron group and 1167 mL/min (IQR, 887-1449 mL/min) in the placebo group. The primary end point, change in peak V̇o2 at 16 weeks, did not significantly differ between the oral iron and placebo groups (+23 mL/min vs -2 mL/min; difference, 21 mL/min [95% CI, -34 to +76 mL/min]; P = .46). Similarly, at 16 weeks, there were no significant differences between treatment groups in changes in 6-minute walk distance (-13 m; 95% CI, -32 to 6 m), NT-proBNP levels (159; 95% CI, -280 to 599 pg/mL), or KCCQ score (1; 95% CI, -2.4 to 4.4), all P \u3e .05.
Conclusions and Relevance: Among participants with HFrEF with iron deficiency, high-dose oral iron did not improve exercise capacity over 16 weeks. These results do not support use of oral iron supplementation in patients with HFrEF.
Trial Registration: clinicaltrials.gov Identifier: NCT02188784
Evidence for sinistral strike-slip deformation in the Solomon Island arc
6 pages, 4 figuresDuring the SOPACMAPS 2 crusie carried out by IFREMER (Institut Français de Recherche pour l'Exploitation de la Mer) and ORSTOM (Institut Français de Recherche Scientifique pour le dévelopement en Coopération) on theR/V L'Atalante, in the Central Solomon Arc area, multibeam bathymetric and imagery data and single-channel seismic reflection profiles were collected from an area of about 3500 km2, to evaluate regional tectonics. Structural data geophysical profiles interpretation provide evidence for left-lateral transtensional tectonics on the southern edge of the Central Solomon Trough. This transtensional deformation is represented by faulting, block tilting, and rhombohedral deformation. The regional geology and the analysis of the sedimentary cover allow us to demonstrate that this tectonic occurred in two different phases during Oligocene to Miocene and Pliocene to Pleistocene timesPeer reviewe
Functional diversification of maize RNA polymerase IV and V subtypes via alternative catalytic subunits.
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Angioimmunoblastic T-cell lymphoma and Kaposi sarcoma: A fortuitous collision?
Follicular helper T-cell (TFH) lymphoma of the angioimmunoblastic-type (AITL), one of the most prevalent T-cell lymphomas, typically encompasses proliferation of high endothelial venules and Epstein-Barr virus-positive immunoblasts, but neither infection with HHV8 nor association with Kaposi's sarcoma (KS) have been described. The aims of this study are to characterise the association between AITL and HHV8 infection or KS.
Three male patients aged 49-76 years, HIV-negative, with concurrent nodal involvement by AITL and KS, were identified from our files and carefully studied. Two patients originated from countries where endemic KS occurs, including one with cutaneous KS. The lymphomas featured abundant vessels, expanded follicular dendritic cells and neoplastic TFH cells [PD1+ (three of three), ICOS+ (three of three), CXCL13+ (three of three), CD10 <sup>+</sup> (two of three), BCL6 (two of three)] but lacked EBV+ immunoblasts. The foci of KS consisted of subcapsular proliferations of ERG+, CD31 <sup>+</sup> and/or CD34 <sup>+</sup> , HHV8+ spindle cells. High-throughput sequencing showed AITL-associated mutations in TET2 (three of three), RHOA (G17V) (three of three) and IDH2 (R172) (two of three), which were absent in the microdissected KS component in two cases. Relapses in two patients consisted of AITL, without evidence of KS. No evidence of HHV8 infection was found in a control group of 23 AITL cases.
Concurrent nodal involvement by AITL and KS is rare and identification of both neoplastic components may pose diagnostic challenges. The question of whether the association between AITL and KS may be fortuitous or could reflect the underlying immune dysfunction in AITL remains open
The Macronuclear Genome of \u3cem\u3eStentor coeruleus\u3c/em\u3e Reveals Tiny Introns in a Giant Cell
The giant, single-celled organism Stentor coeruleus has a long history as a model system for studying pattern formation and regeneration in single cells. Stentor [1, 2] is a heterotrichous ciliate distantly related to familiar ciliate models, such as Tetrahymena or Paramecium. The primary distinguishing feature of Stentor is its incredible size: a single cell is 1 mm long. Early developmental biologists, including T.H. Morgan [3], were attracted to the system because of its regenerative abilities—if large portions of a cell are surgically removed, the remnant reorganizes into a normal-looking but smaller cell with correct proportionality [2, 3]. These biologists were also drawn to Stentor because it exhibits a rich repertoire of behaviors, including light avoidance, mechanosensitive contraction, food selection, and even the ability to habituate to touch, a simple form of learning usually seen in higher organisms [4]. While early microsurgical approaches demonstrated a startling array of regenerative and morphogenetic processes in this single-celled organism, Stentor was never developed as a molecular model system. We report the sequencing of the Stentor coeruleus macronuclear genome and reveal key features of the genome. First, we find that Stentor uses the standard genetic code, suggesting that ciliate-specific genetic codes arose after Stentor branched from other ciliates. We also discover that ploidy correlates with Stentor’s cell size. Finally, in the Stentor genome, we discover the smallest spliceosomal introns reported for any species. The sequenced genome opens the door to molecular analysis of single-cell regeneration in Stentor
Advanced optical imaging in living embryos
Developmental biology investigations have evolved from static studies of embryo anatomy and into dynamic studies of the genetic and cellular mechanisms responsible for shaping the embryo anatomy. With the advancement of fluorescent protein fusions, the ability to visualize and comprehend how thousands to millions of cells interact with one another to form tissues and organs in three dimensions (xyz) over time (t) is just beginning to be realized and exploited. In this review, we explore recent advances utilizing confocal and multi-photon time-lapse microscopy to capture gene expression, cell behavior, and embryo development. From choosing the appropriate fluorophore, to labeling strategy, to experimental set-up, and data pipeline handling, this review covers the various aspects related to acquiring and analyzing multi-dimensional data sets. These innovative techniques in multi-dimensional imaging and analysis can be applied across a number of fields in time and space including protein dynamics to cell biology to morphogenesis
Monomorphic epitheliotropic intestinal T-cell lymphoma comprises morphologic and genomic heterogeneity impacting outcome.
Monomorphic epitheliotropic intestinal T-cell lymphoma (MEITL) is a rare aggressive T-cell lymphoma most reported in Asia. We performed a comprehensive clinical, pathological and genomic study of 71 European MEITL patients (36 males; 35 females, median age 67 years). The majority presented with gastrointestinal involvement and had emergency surgery, and 40% had stage IV disease. The tumors were morphologically classified into two groups: typical (58%) and atypical (i.e. nonmonomorphic or with necrosis, angiotropism or starry-sky pattern) (42%), sharing a homogeneous immunophenotypic profile (CD3+ (98%) CD4- (94%) CD5- (97%) CD7+ (97%) CD8+ (90%) CD56+ (86%) CD103+ (80%) cytotoxic marker+ (98%)) with more frequent expression of TCRgd (50%) than TCRab (32%). MYC expression (30% of cases) partly reflecting MYC gene locus alterations, correlated with nonmonomorphic cytology. Almost all cases (97%) harbored deleterious mutation(s) and/or deletion of the SETD2 gene and 90% had defective H3K36 trimethylation. Other frequently mutated genes were STAT5B (57%), JAK3 (50%), TP53 (35%) JAK1 (12.5%), BCOR and ATM (11%). Both TP53 mutations and MYC expression correlated with atypical morphology. The median overall survival (OS) of 63 patients (43/63 only received chemotherapy after initial surgery) was 7.8 months. Multivariate analysis found a strong negative impact on outcome of MYC expression, TP53 mutation, STAT5B mutation and poor performance status while aberrant B-cell marker expression (20% of cases) correlated with better survival. In conclusion, MEITL is an aggressive disease with resistance to conventional therapy, predominantly characterized by driver gene alterations deregulating histone methylation and JAK/STAT signalling and encompasses genetic and morphologic variants associated with very high clinical risk
Integrating forest structural diversity measurement into ecological research
The measurement of forest structure has evolved steadily due to advances in technology, methodology, and theory. Such advances have greatly increased our capacity to describe key forest structural elements and resulted in a range of measurement approaches from traditional analog tools such as measurement tapes to highly derived and computationally intensive methods such as advanced remote sensing tools (e.g., lidar, radar). This assortment of measurement approaches results in structural metrics unique to each method, with the caveat that metrics may be biased or constrained by the measurement approach taken. While forest structural diversity (FSD) metrics foster novel research opportunities, understanding how they are measured or derived, limitations of the measurement approach taken, as well as their biological interpretation is crucial for proper application. We review the measurement of forest structure and structural diversity—an umbrella term that includes quantification of the distribution of functional and biotic components of forests. We consider how and where these approaches can be used, the role of technology in measuring structure, how measurement impacts extend beyond research, and current limitations and potential opportunities for future research
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