1,729 research outputs found
The circumgalactic medium in Lyman-alpha: a new constraint on galactic outflow models
Galactic outflows are critical to our understanding of galaxy formation and
evolution. However the details of the underlying feedback process remain
unclear. We compare Ly observations of the circumgalactic medium (CGM)
of Lyman Break Galaxies (LBGs) with mock observations of their simulated CGM.
We use cosmological hydrodynamical `zoom-in' simulations of an LBG which
contains strong, momentum-driven galactic outflows. Simulation snapshots at
and are used, corresponding to the available observational
data. The simulation is post-processed with the radiative transfer code
\textsc{crash} to account for the impact of ionising photons on hydrogen gas
surrounding the simulated LBG. We generate mock absorption line maps for
comparison with data derived from observed close galaxy-galaxy pairs. We
perform calculations of Ly photons scattering through the CGM with our
newly developed Monte-Carlo code \textsc{slaf}, and compare to observations of
diffuse Ly halos around LBGs. Our fiducial galactic outflow model comes
closer to reproducing currently observed characteristics of the CGM in
Ly than a reference inefficient feedback model used for comparison.
Nevertheless, our fiducial model still struggles to reproduce the observed data
of the inner CGM (at impact parameter kpc). Our results suggest that
galactic outflows affect Ly absorption and emission around galaxies
mostly at impact parameters kpc, while cold accretion flows dominate at
larger distances. We discuss the implications of this result, and underline the
potential constraining power of CGM observations - in emission and absorption -
on galactic outflow models.Comment: 14 pages, 12 figure
Intra-abdominal hypertension and abdominal compartment syndrome in pancreatitis, paediatrics, and trauma
Intra-abdominal hypertension (IAH) is an important contributor to early organ dysfunction in trauma and sepsis. However, relatively little is known about the impact of intra-abdominal pressure (IAP) in general internal medicine, pregnant patients, and those with obesity or burns. The aim of this paper is to review the pathophysiologic implications and treatment options for IAH in these specific situations. A MEDLINE and PubMed search was performed and the resulting body-of-evidence included in the current review on the basis of relevance and scientific merit. There is increasing awareness of the role of IAH in different clinical situations. Specifically, IAH will develop in most (if not all) severely burned patients, and may contribute to early mortality. One should avoid over-resuscitation of these patients with large volumes of fluids, especially crystalloids. Acute elevations in IAP have similar effects in obese patients compared to non-obese patients, but the threshold IAP associated with organ dysfunction may be higher. Chronic elevations in IAP may, in part, be responsible for the pathogenesis of obesity-related co-morbid conditions such as hypertension, pseudotumor cerebri, pulmonary dysfunction, gastroesophageal reflux disease, and abdominal wall hernias. At the bedside, measuring IAP and considering IAH in all critical maternal conditions is essential, especially in preeclampsia/eclampsia where some have hypothesized that IAH may have an additional role. IAH in pregnancy must take into account the precautions for aorto-caval compression and has been associated with ovarian hyperstimulation syndrome. Recently, IAP has been associated with the cardiorenal dilemma and hepatorenal syndrome, and this has led to the recognition of the polycompartment syndrome. In conclusion, IAH and ACS have been associated with several patient populations beyond the classical ICU, surgical, and trauma patients. In all at risk conditions the focus should be on the early recognition of IAH and prevention of ACS. Patients at risk for IAH should be identified early through measurements of IAP. Appropriate actions should be taken when IAP increases above 15 mm Hg, especially if pressures reach above 20 mm Hg with new onset organ failure. Although non-operative measures come first, surgical decompression must not be delayed if these fail. Percutaneous drainage of ascites is a simple and potentially effective tool to reduce IAP if organ dysfunction develops, especially in burn patients. Escharotomy may also dramatically reduce IAP in the case of abdominal burns
Cloning and Characterization of TaTGW-7A Gene Associated with Grain Weight in Wheat via SLAF-seq-BSA
Thousand-grain weight (TGW) of wheat (Triticum aestivum L.) contributes significantly to grain yield. In the present study, a candidate gene associated with TGW was identified through specific-locus amplified fragment sequencing (SLAF-seq) of DNA bulks of recombinant inbred lines (RIL) derived from the cross between Jing 411 and Hongmangchun 21. The gene was located on chromosome 7A, designated as TaTGW-7A with a complete genome sequence and an open reading frame (ORF). A single nucleotide polymorphism (SNP) was present in the first exon between two alleles at TaTGW-7A locus, resulting in a Val to Ala substitution, corresponding to a change from higher to lower TGW. Cleaved amplified polymorphic sequence (CAPS) (TGW7A) and InDel (TG9) markers were developed to discriminate the two alleles TaTGW-7Aa and TaTGW-7Ab for higher and lower TGW, respectively. A major QTL co-segregating with TaTGW-7A explained 21.7–27.1% of phenotypic variance for TGW in the RIL population across five environments. The association of TaTGW-7A with TGW was further validated in a natural population and Chinese mini-core collections. Quantitative real-time PCR revealed higher transcript levels of TaTGW-7Aa than those of TaTGW-7Ab during grain development. High frequencies of the superior allele TaTGW-7Aa for higher TGW in Chinese mini-core collections (65.0%) and 501 wheat varieties (86.0%) indicated a strong and positive selection of this allele in wheat breeding. The molecular markers TGW7A and TG9 can be used for improvement of TGW in breeding programs
On the Robustness of Question Rewriting Systems to Questions of Varying Hardness
In conversational question answering (CQA), the task of question
rewriting~(QR) in context aims to rewrite a context-dependent question into an
equivalent self-contained question that gives the same answer. In this paper,
we are interested in the robustness of a QR system to questions varying in
rewriting hardness or difficulty. Since there is a lack of questions classified
based on their rewriting hardness, we first propose a heuristic method to
automatically classify questions into subsets of varying hardness, by measuring
the discrepancy between a question and its rewrite. To find out what makes
questions hard or easy for rewriting, we then conduct a human evaluation to
annotate the rewriting hardness of questions. Finally, to enhance the
robustness of QR systems to questions of varying hardness, we propose a novel
learning framework for QR that first trains a QR model independently on each
subset of questions of a certain level of hardness, then combines these QR
models as one joint model for inference. Experimental results on two datasets
show that our framework improves the overall performance compared to the
baselines.Comment: ACL'22, main, long pape
The emerging oilseed crop Sesamum indicum enters the “Omics” era
Sesame (Sesamum indicum L.) is one of the oldest oilseed crops widely grown in Africa and Asia for its high-quality nutritional seeds. It is well adapted to harsh environments and constitutes an alternative cash crop for smallholders in developing countries. Despite its economic and nutritional importance, sesame is considered as an orphan crop because it has received very little attention from science. As a consequence, it lags behind the other major oil crops as far as genetic improvement is concerned. In recent years, the scenario has considerably changed with the decoding of the sesame nuclear genome leading to the development of various genomic resources including molecular markers, comprehensive genetic maps, high-quality transcriptome assemblies, web-based functional databases and diverse daft genome sequences. The availability of these tools in association with the discovery of candidate genes and quantitative trait locis for key agronomic traits including high oil content and quality, waterlogging and drought tolerance, disease resistance, cytoplasmic male sterility, high yield, pave the way to the development of some new strategies for sesame genetic improvement. As a result, sesame has graduated from an “orphan crop” to a “genomic resource-rich crop.” With the limited research teams working on sesame worldwide, more synergic efforts are needed to integrate these resources in sesame breeding for productivity upsurge, ensuring food security and improved livelihood in developing countries. This review retraces the evolution of sesame research by highlighting the recent advances in the “Omics” area and also critically discusses the future prospects for a further genetic improvement and a better expansion of this crop. (Résumé d'auteur
High-density SNP map facilitates fine mapping of QTLs and candidate genes discovery for Aspergillus flavus resistance in peanut (Arachis hypogaea)
Aflatoxin contamination in peanuts caused by Aspergillus flavus is a serious food safety issue for human health
around the world. Host plant resistance to fungal infection and reduction in aflatoxin are crucial for mitigating this problem.
Identification of the resistance-linked markers can be used in marker-assisted breeding for varietal development. Here we
report construction of two high-density genetic linkage maps with 1975 SNP loci and 5022 SNP loci, respectively. Two
consistent quantitative trait loci (QTL) were identified as qRAF-3-1 and qRAF-14-1, which located on chromosomes A03
and B04, respectively. QTL qRAF-3-1 was mapped within 1.67 cM and had more than 19% phenotypic variance explained
(PVE), while qRAF-14-1 was located within 1.34 cM with 5.15% PVE. While comparing with the reference genome, the
mapped QTLs, qRAF-3-1 and qRAF-14-1, were located within a physical distance of 1.44 Megabase pair (Mbp) and 2.22
Mbp, harboring 67 and 137 genes, respectively. Among the identified candidate genes, six genes with the same function were
found within both QTLs regions. In addition, putative disease resistance RPP13-like protein 1 (RPP13), lipoxygenase (Lox),
WRKY transcription factor (WRKY) and cytochrome P450 71B34 genes were also identified. Using microarray analysis,
genes responded to A. flavus infection included coding for RPP13, pentatricopeptide repeat-containing-like protein, and
Lox which may be possible candidate genes for resistance to A. flavus. The QTLs and candidate genes will further facilitate
marker development and validation of genes for deployment in the molecular breeding programs against A. flavus in peanuts
- …