316 research outputs found

    Anti-Hyperon Enhancement through Baryon Junction Loops

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    The baryon junction exchange mechanism recently proposed to explain valence baryon number transport in nuclear collisions is extended to study midrapidity anti-hyperon production. Baryon junction-anti-junction (J anti-J) loops are shown to enhance anti-Lambda, anti-Xi, anti-Omega yields as well as lead to long range rapidity correlations. Results are compared to recent WA97 Pb + Pb -> Y + anti-Y + X data.Comment: 10 pages, 4 figure

    The effect of finite-range interactions in classical transport theory

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    The effect of scattering with non-zero impact parameters between consituents in relativistic heavy ion collisions is investigated. In solving the relativistic Boltzmann equation, the characteristic range of the collision kernel is varied from approximately one fm to zero while leaving the mean-free path unchanged. Modifying this range is shown to significantly affect spectra and flow observables. The finite range is shown to provide effective viscosities, shear, bulk viscosity and heat conductivity, with the viscous coefficients being proportional to the square of the interaction range

    Fat mass and obesity associated (FTO) gene influences skeletal muscle phenotypes in non-resistance trained males and elite rugby playing position

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    Background FTO gene variants have been associated with obesity phenotypes in sedentary and obese populations, but rarely with skeletal muscle and elite athlete phenotypes. Methods In 1089 participants, comprising 530 elite rugby athletes and 559 non-athletes, DNA was collected and genotyped for the FTO rs9939609 variant using real-time PCR. In a subgroup of non-resistance trained individuals (NT; n = 120), we also assessed structural and functional skeletal muscle phenotypes using dual energy x-ray absorptiometry, ultrasound and isokinetic dynamometry. In a subgroup of rugby athletes (n = 77), we assessed muscle power during a countermovement jump. Results In NT, TT genotype and T allele carriers had greater total body (4.8% and 4.1%) and total appendicular lean mass (LM; 3.0% and 2.1%) compared to AA genotype, with greater arm LM (0.8%) in T allele carriers and leg LM (2.1%) for TT, compared to AA genotype. Furthermore, the T allele was more common (94%) in selected elite rugby union athletes (back three and centre players) who are most reliant on LM rather than total body mass for success, compared to other rugby athletes (82%; P = 0.01, OR = 3.34) and controls (84%; P = 0.03, OR = 2.88). Accordingly, these athletes had greater peak power relative to body mass than other rugby athletes (14%; P = 2 x 10-6). Conclusion Collectively, these results suggest that the T allele is associated with increased LM and elite athletic success. This has implications for athletic populations, as well as conditions characterised by low LM such as sarcopenia and cachexia

    Broad clinical phenotypes associated with TAR-DNA binding protein (TARDBP) mutations in amyotrophic lateral sclerosis

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    The finding of TDP-43 as a major component of ubiquitinated protein inclusions in amyotrophic lateral sclerosis (ALS) has led to the identification of 30 mutations in the transactive response-DNA binding protein (TARDBP) gene, encoding TDP-43. All but one are in exon 6, which encodes the glycine-rich domain. The aim of this study was to determine the frequency of TARDBP mutations in a large cohort of motor neurone disease patients from Northern England (42 non-superoxide dismutase 1 (SOD1) familial ALS (FALS), nine ALS-frontotemporal dementia, 474 sporadic ALS (SALS), 45 progressive muscular atrophy cases). We identified four mutations, two of which were novel, in two familial (FALS) and two sporadic (SALS) cases, giving a frequency of TARDBP mutations in non-SOD1 FALS of 5% and SALS of 0.4%. Analysis of clinical data identified that patients had typical ALS, with limb or bulbar onset, and showed considerable variation in age of onset and rapidity of disease course. However, all cases had an absence of clinically overt cognitive dysfunction

    Comparing pediatric gastroenteritis emergency department care in Canada and the United States

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    BACKGROUND: Between-country variation in health care resource use and its impact on outcomes in acute care settings have been challenging to disentangle from illness severity by using administrative data. METHODS: We conducted a preplanned analysis employing patient-level emergency department (ED) data from children enrolled in 2 previously conducted clinical trials. Participants aged 3 to,48 months with,72 hours of gastroenteritis were recruited in pediatric EDs in the United States (N = 10 sites; 588 participants) and Canada (N = 6 sites; 827 participants). The primary outcome was an unscheduled health care provider visit within 7 days; the secondary outcomes were intravenous fluid administration and hospitalization at or within 7 days of the index visit. RESULTS: In adjusted analysis, unscheduled revisits within 7 days did not differ (adjusted odds ratio [aOR]: 0.72; 95% confidence interval (CI): 0.50 to 1.02). At the index ED visit, although participants in Canada were assessed as being more dehydrated, intravenous fluids were administered more frequently in the United States (aOR: 4.6; 95% CI: 2.9 to 7.1). Intravenous fluid administration rates did not differ after enrollment (aOR: 1.4; 95% CI: 0.7 to 2.8; US cohort with Canadian as referent). Overall, intravenous rehydration was higher in the United States (aOR: 3.8; 95% CI: 2.5 to 5.7). Although hospitalization rates during the 7 days after enrollment (aOR: 1.1; 95% CI: 0.4 to 2.6) did not differ, hospitalization at the index visit was more common in the United States (3.9% vs 2.3%; aOR: 3.2; 95% CI: 1.6 to 6.8). CONCLUSIONS: Among children with gastroenteritis and similar disease severity, revisit rates were similar in our 2 study cohorts, despite lower rates of intravenous rehydration and hospitalization in Canadian-based EDs

    Variables Associated with Intravenous Rehydration and Hospitalization in Children with Acute Gastroenteritis: A Secondary Analysis of 2 Randomized Clinical Trials

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    Importance: Despite guidelines endorsing oral rehydration therapy, intravenous fluids are commonly administered to children with acute gastroenteritis in high-income countries. Objective: To identify factors associated with intravenous fluid administration and hospitalization in children with acute gastroenteritis. Design, Setting, and Participants: This study is a planned secondary analysis of the Pediatric Emergency Research Canada (PERC) and Pediatric Emergency Care Applied Research Network (PECARN) probiotic trials. Participants include children aged 3 to 48 months with 3 or more watery stools in 24 hours between November 5, 2013, and April 7, 2017, for the PERC study and July 8, 2014, and June 23, 2017, for the PECARN Study. Children were from 16 pediatric emergency departments throughout Canada (6) and the US (10). Data were analyzed from November 2, 2018, to March 16, 2021. Exposures: Sex, age, preceding health care visit, distance between home and hospital, country (US vs Canada), frequency and duration of vomiting and diarrhea, presence of fever, Clinical Dehydration Scale score, oral ondansetron followed by oral rehydration therapy, and infectious agent. Main Outcomes and Measures: Intravenous fluid administration and hospitalization. Results: This secondary analysis of 2 randomized clinical trials included 1846 children (mean [SD] age, 19.1 [11.4] months; 1007 boys [54.6%]), of whom 534 of 1846 (28.9%) received oral ondansetron, 240 of 1846 (13.0%) received intravenous rehydration, and 67 of 1846 (3.6%) were hospitalized. The following were independently associated with intravenous rehydration: higher Clinical Dehydration Scale score (mild to moderate vs none, odds ratio [OR], 8.73; 95% CI, 5.81-13.13; and severe vs none, OR, 34.15; 95% CI, 13.45-86.73); country (US vs Canada, OR, 6.76; 95% CI, 3.15-14.49); prior health care visit with intravenous fluids (OR, 4.55; 95% CI, 1.32-15.72); and frequency of vomiting (per 5 episodes, OR, 1.66; 95% CI, 1.39-1.99). The following were independently associated with hospitalization: higher Clinical Dehydration Scale score (mild to moderate vs none, OR, 11.10; 95% CI, 5.05-24.38; and severe vs none, OR, 23.55; 95% CI, 7.09-78.25) and country (US vs Canada, OR, 3.37; 95% CI, 1.36-8.40). Oral ondansetron was associated with reduced odds of intravenous rehydration (OR, 0.21; 95% CI, 0.13-0.32) and hospitalization (OR, 0.44; 95% CI, 0.21-0.89). Conclusions and Relevance: Intravenous rehydration and hospitalization were associated with clinical evidence of dehydration and lack of an oral ondansetron-supported oral rehydration period. Strategies focusing on oral ondansetron administration followed by oral rehydration therapy in children with dehydration may reduce the reliance on intravenous rehydration and hospitalization. Trial Registration: ClinicalTrials.gov Identifiers: NCT01853124 (PERC) and NCT01773967 (PECARN)

    Transmisión de Klebsiella pneumoniae resistente a carbapenemes en hospitales de EE.UU.

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    Antecedentes. La Klebsiella pneumoniae resistente a los carbapenemes (CRKp) es el Enterobacterales resistente a los carbapenemes más prevalente en los Estados Unidos. Se evaluó la agrupación de CRKp en pacientes de hospitales estadounidenses. Métodos. De abril de 2016 a agosto de 2017, 350 pacientes con grupo clonal 258 CRKp se inscribieron en el Consortium on Resistance Against Carbapenems in Klebsiella and other Enterobacteriaceae, un estudio de cohortes prospectivo y multicéntrico. Se construyó un árbol de máxima verosimilitud utilizando RAxML. Los conglomerados estáticos compartían ≤21 polimorfismos de un solo nucleótido (SNP) y un ancestro común más reciente. Los conglomerados dinámicos incorporaron la distancia SNP, el tiempo de cultivo y las tasas de acumulación y transmisión SNP utilizando el programa R TransCluster. Resultados. La mayoría de los pacientes ingresaron desde su domicilio (n=150, 43%) o desde centros de cuidados de larga duración (n=115, 33%). La orina (n=149, 43%) fue el lugar de aislamiento más común. En total, se identificaron 55 conglomerados estáticos y 47 dinámicos en 210 de 350 (60%) y 194 de 350 (55%) pacientes, respectivamente. Aproximadamente la mitad de los clusters estáticos eran idénticos a los dinámicos. Los conglomerados estáticos consistían en 33 (60%) conglomerados intrasistema y 22 (40%) conglomerados intersistema. Los conglomerados dinámicos estaban formados por 32 (68%) conglomerados intrasistema y 15 (32%) conglomerados intersistema y presentaban menos diferencias de SNP que los conglomerados estáticos (8 frente a 9; P=.045; intervalo de confianza [IC] del 95%: -4 a 0). Los conglomerados dinámicos intersistema contenían más pacientes que los conglomerados dinámicos intrasistema (mediana [intervalo intercuartílico], 4 [2, 7] frente a 2 [2, 2]; P=,007; IC del 95%: -3 a 0). Conclusiones. Se identificó una amplia transmisión intrasistémica e intersistémica de CRKp en pacientes estadounidenses hospitalizados. El uso de diferentes métodos para evaluar la similitud genética sólo dio lugar a diferencias menores en la interpretación.Background. Carbapenem-resistant Klebsiella pneumoniae (CRKp) is the most prevalent carbapenem-resistant Enterobacterales in the United States. We evaluated CRKp clustering in patients in US hospitals. Methods. From April 2016 to August 2017, 350 patients with clonal group 258 CRKp were enrolled in the Consortium on Resistance Against Carbapenems in Klebsiella and other Enterobacteriaceae, a prospective, multicenter, cohort study. A maximum likelihood tree was constructed using RAxML. Static clusters shared ≤21 single-nucleotide polymorphisms (SNP) and a most recent common ancestor. Dynamic clusters incorporated SNP distance, culture timing, and rates of SNP accumulation and transmission using the R program TransCluster. Results. Most patients were admitted from home (n=150, 43%) or long-term care facilities (n=115, 33%). Urine (n=149, 43%) was the most common isolation site. Overall, 55 static and 47 dynamics clusters were identified involving 210 of 350 (60%) and 194 of 350 (55%) patients, respectively. Approximately half of static clusters were identical to dynamic clusters. Static clusters consisted of 33 (60%) intrasystem and 22 (40%) intersystem clusters. Dynamic clusters consisted of 32 (68%) intrasystem and 15 (32%) intersystem clusters and had fewer SNP differences than static clusters (8 vs 9; P=.045; 95% confidence interval [CI]: −4 to 0). Dynamic intersystem clusters contained more patients than dynamic intrasystem clusters (median [interquartile range], 4 [2, 7] vs 2 [2, 2]; P=.007; 95% CI: −3 to 0). Conclusions. Widespread intrasystem and intersystem transmission of CRKp was identified in hospitalized US patients. Use of different methods for assessing genetic similarity resulted in only minor differences in interpretation

    Discriminative Value of Inflammatory Biomarkers for Suspected Sepsis

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    Circulating biomarkers can facilitate sepsis diagnosis enabling early management and improved outcomes. Procalcitonin (PCT) has been suggested to have superior diagnostic utility compared to other biomarkers

    Substrate age and tree islands influence carbon and nitrogen dynamics across a retrogressive semiarid chronosequence

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    The long-term dynamics of carbon (C) and nitrogen (N) in semiarid ecosystems remain poorly understood. We measured pools and fluxes of surface soil C and N, as well as other soil properties, under tree canopies and in intercanopy spaces at four sites that form a volcanic substrate age gradient in semiarid piñon-juniper woodlands of northern Arizona, United States. Clay content and soil water-holding capacity increased consistently with substrate age, but both soil organic C and N increased only up to the 750,000 year site and then declined at the oldest (3,000,000 year) site. Measures of soil C and N flux displayed a similar pattern to total C and N pools. Pools and fluxes of C and N among the three canopy types became more homogeneous with substrate age up to the 750,000 year site, but disparity between tree and intercanopy microsites widened again at the oldest site. The δ15N of both tree leaves and surface soils became progressively more enriched across the substrate age gradient, consistent with a N cycle increasingly dominated by isotope fractionating losses. Our results point to consistencies in patterns of ecosystem development between semiarid and more humid ecosystems and suggest that pedogenic development may be an important factor controlling the spatial distribution of soil resources in semiarid ecosystems. These data should help both unify and broaden current theory of terrestrial ecosystem development
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