878 research outputs found

    Faster turnover of new soil carbon inputs under increased atmospheric CO2

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    This is the author accepted manuscript. The final version is available from Wiley via the DOI in this record.Rising levels of atmospheric CO2 frequently stimulate plant inputs to soil, but the consequences of these changes for soil carbon (C) dynamics are poorly understood. Plant-derived inputs can accumulate in the soil and become part of the soil C pool ("new soil C"), or accelerate losses of pre-existing ("old") soil C. The dynamics of the new and old pools will likely differ and alter the long-term fate of soil C, but these separate pools, which can be distinguished through isotopic labeling, have not been considered in past syntheses. Using meta-analysis, we found that while elevated CO2 (ranging from 550 to 800 parts per million by volume) stimulates the accumulation of new soil C in the short term (<1 year), these effects do not persist in the longer term (1-4 years). Elevated CO2 does not affect the decomposition or the size of the old soil C pool over either temporal scale. Our results are inconsistent with predictions of conventional soil C models and suggest that elevated CO2 might increase turnover rates of new soil C. Because increased turnover rates of new soil C limit the potential for additional soil C sequestration, the capacity of land ecosystems to slow the rise in atmospheric CO2 concentrations may be smaller than previously assumed.This work was supported by the U.S. Department of Energy (DOE), Office of Science, Biological and Environmental Research Program, under Award Number DE-SC-0010632. R.P.P. was supported by the U.S. Department of Agriculture NRI CSREES Program and by DOEs Terrestrial Ecosystem Science Program in the Climate and Environmental Sciences Division

    Mixed sums of primes and other terms

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    In this paper we study mixed sums of primes and linear recurrences. We show that if m=2(mod 4) and m+1 is a prime then (m2n−1−1)/(m−1)=Ìžmn+pa(m^{2^n-1}-1)/(m-1)\not=m^n+p^a for any n=3,4,... and prime power p^a. We also prove that if a>1 is an integer, u_0=0, u_1=1 and u_{i+1}=au_i+u_{i-1} for i=1,2,3,..., then all the sums u_m+au_n (m,n=1,2,3,...) are distinct. One of our conjectures states that any integer n>4 can be written as the sum of an odd prime, an odd Fibonacci number and a positive Fibonacci number.Comment: 11 page

    Detection of Maternal Alcohol Use Problems in the Pediatric Emergency Department

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    Maternal alcohol use problems may impact the health and well-being of children, but often remain unrecognized. Mothers of young children seldom seek outpatient care for themselves; thus, pediatric settings may present an opportunity for the detection of maternal alcohol use problems. This study examines the feasibility of screening for and prevalence of alcohol use problems in mothers of young children in the context of seeking pediatric emergency care. We also examined the relationship of maternal alcohol use problems with use of pediatric emergency care. Methods : A total of 361 English-speaking mothers of children aged 7 and younger completed screening measures during their child's emergency care visit. TWEAK was used to screen for alcohol use problems. The screening survey also included information on children's health status and health care use, demographics, and the Center for Epidemiological Studies Depression Scale. Results : Of the women approached, 90% agreed to complete the screening measure. On the basis of cutoff score of 2 or more, 7% of women had elevated TWEAK scores. Those women with a TWEAK score >2 reported greater use of the pediatric emergency department (PED) than women scoring below the cutoff. On the basis of multivariate analyses, significant predictors of recent PED use included the presence of child chronic illness, younger maternal age, and TWEAK score. Conclusions : Screening for alcohol use problems among mothers of young children using the TWEAK appears to be feasible in a busy PED setting. The PED setting is promising for identifying risk drinking among women who may be less likely to be otherwise detected and for whom alcohol use may be impacting child outcomes.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/66222/1/j.1530-0277.2006.00132.x.pd

    Mindfulness interventions in medical education: A systematic review of their impact on medical student stress, depression, fatigue and burnout

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    Introduction: Mindfulness-based interventions (MBIs) have gained popularity in medical education. A systematic review was conducted to determine the effectiveness of MBIs for reducing psychological distress in undergraduate medical students. Methods: A search protocol was conducted using online databases Embase, PubMed, PsycINFO, and MEDLINE. Articles were required to meet the following criteria to be included: (1) describe a MBI or use of mindfulness exercises as part of an intervention, (2) include at least one of: stress, burnout, fatigue, or depression, as an outcome, (3) include quantitative outcomes, and (4) published in English in a peer-reviewed journal. Results: Twelve articles were reviewed. Seven studies reported improvements in at least one targeted outcome. Four of seven studies exploring the impact on stress reported improvements. Five articles studying depression reported reductions. One study exploring burnout reported a decrease on a single subscale. Only one study measured the impact on fatigue (no change reported). Half of studies reviewed included predominantly female samples. Conclusions: Mixed evidence was found for the use of MBIs for reducing psychological distress in undergraduate medical students. Future work should aim to clarify the impact of mindfulness on burnout and fatigue, and explore the replicability of improvements in male medical students alone

    Experimental and theoretical investigation of ligand effects on the synthesis of ZnO nanoparticles

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    ZnO nanoparticles with highly controllable particle sizes(less than 10 nm) were synthesized using organic capping ligands in Zn(Ac)2 ethanolic solution. The molecular structure of the ligands was found to have significant influence on the particle size. The multi-functional molecule tris(hydroxymethyl)-aminomethane (THMA) favoured smaller particle distributions compared with ligands possessing long hydrocarbon chains that are more frequently employed. The adsorption of capping ligands on ZnnOn crystal nuclei (where n = 4 or 18 molecular clusters of(0001) ZnO surfaces) was modelled by ab initio methods at the density functional theory (DFT) level. For the molecules examined, chemisorption proceeded via the formation of Zn...O, Zn...N, or Zn...S chemical bonds between the ligands and active Zn2+ sites on ZnO surfaces. The DFT results indicated that THMA binds more strongly to the ZnO surface than other ligands, suggesting that this molecule is very effective at stabilizing ZnO nanoparticle surfaces. This study, therefore, provides new insight into the correlation between the molecular structure of capping ligands and the morphology of metal oxide nanostructures formed in their presence

    Vestibular and balance dysfunction in children with congenital CMV: a systematic review.

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    OBJECTIVE: This systematic review evaluates vestibular and balance dysfunction in children with congenital cytomegalovirus (cCMV), makes recommendations for clinical practice and informs future research priorities. DESIGN: MEDLINE, Embase, EMCARE, BMJ Best Practice, Cochrane Library, DynaMed Plus and UpToDate were searched from inception to 20 March 2021 and graded according to Strengthening the Reporting of Observational Studies in Epidemiology (STROBE) criteria. PATIENTS: Children with cCMV diagnosed within 3 weeks of life from either blood, saliva and/or urine (using either PCR or culture). INTERVENTION: Studies of vestibular function and/or balance assessments. MAIN OUTCOME MEASURES: Vestibular function and balance. RESULTS: 1371 studies were identified, and subsequently 16 observational studies were eligible for analysis, leading to an overall cohort of 600 children with cCMV. All studies were of low/moderate quality. In 12/16 studies, vestibular function tests were performed. 10/12 reported vestibular dysfunction in ≄40% of children with cCMV. Three studies compared outcomes for children with symptomatic or asymptomatic cCMV at birth; vestibular dysfunction was more frequently reported in children with symptomatic (22%-60%), than asymptomatic cCMV (0%-12.5%). Two studies found that vestibular function deteriorated over time: one in children (mean age 7.2 months) over 10 months and the other (mean age 34.7 months) over 26 months. CONCLUSIONS: Vestibular dysfunction is found in children with symptomatic and asymptomatic cCMV and in those with and without hearing loss. Audiovestibular assessments should be performed as part of neurodevelopmental follow-up in children with cCMV. Case-controlled longitudinal studies are required to more precisely characterise vestibular dysfunction and help determine the efficacy of early supportive interventions. PROSPERO REGISTRATION: CRD42019131656

    Group B streptococcal carriage, serotype distribution and antibiotic susceptibilities in pregnant women at the time of delivery in a refugee population on the Thai-Myanmar border

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    <p>Abstract</p> <p>Background</p> <p>Group B Streptococcus (GBS) is the leading cause of neonatal sepsis in the developed world. Little is known about its epidemiology in the developing world, where the majority of deaths from neonatal infections occur. Maternal carriage of GBS is a prerequisite for the development of early onset GBS neonatal sepsis but there is a paucity of carriage data published from the developing world, in particular South East Asia.</p> <p>Methods</p> <p>We undertook a cross sectional study over a 13 month period in a remote South East Asian setting on the Thai-Myanmar border. During labour, 549 mothers had a combined vaginal rectal swab taken for GBS culture. All swabs underwent both conventional culture as well as PCR for GBS detection. Cultured GBS isolates were serotyped by latex agglutination, those that were negative or had a weak positive reaction and those that were PCR positive but culture negative were additionally tested using multiplex PCR based on the detection of GBS capsular polysaccharide genes.</p> <p>Results</p> <p>The GBS carriage rate was 12.0% (95% CI: 9.4-15.0), with 8.6% positive by both culture and PCR and an additional 3.5% positive by PCR alone. Serotypes, Ia, Ib, II, III, IV, V, VI and VII were identified, with II the predominant serotype. All GBS isolates were susceptible to penicillin, ceftriaxone and vancomycin and 43/47 (91.5%) were susceptible to erythromycin and clindamycin.</p> <p>Conclusions</p> <p>GBS carriage is not uncommon in pregnant women living on the Thai-Myanmar border with a large range of serotypes represented.</p

    A Novel Redox Method for Rapid Production of Functional Bi-Specific Antibodies For Use in Early Pilot Studies

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    We demonstrate here a rapid alternative method for the production of functional bi-specific antibodies using the mild reducing agent 2-mercaptoethanesulfonic acid sodium salt (MESNA). Following reduction of a mixture of two monoclonal antibodies with MESNA to break inter heavy chain bonds, this solution is dialysed under oxidising conditions and antibodies are allowed to reform. During this reaction a mixture of antibodies is formed, including parental antibodies and bi-specific antibody. Bi-specific antibodies are purified over two sequential affinity columns. Following purification, bi-specificity of antibodies is determined in enzyme-linked immunosorbent assays and by flow cytometry. Using this redox method we have been successful in producing hybrid and same-species bi-specific antibodies in a time frame of 6–10 working days, making this production method a time saving alternative to the time-consuming traditional heterohybridoma technology for the production of bi-specific antibodies for use in early pilot studies. The use of both rat and mouse IgG antibodies forming a rat/mouse bi-specific antibody as well as producing a pure mouse bi-specific antibody and a pure rat bi-specific antibody demonstrates the flexibility of this production method

    Multijet production in neutral current deep inelastic scattering at HERA and determination of α_{s}

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    Multijet production rates in neutral current deep inelastic scattering have been measured in the range of exchanged boson virtualities 10 5 GeV and –1 < η_{LAB}^{jet} < 2.5. Next-to-leading-order QCD calculations describe the data well. The value of the strong coupling constant α_{s} (M_{z}), determined from the ratio of the trijet to dijet cross sections, is α_{s} (M_{z}) = 0.1179 ± 0.0013 (stat.)_{-0.0046}^{+0.0028}(exp.)_{-0.0046}^{+0.0028}(th.)

    A three year descriptive study of early onset neonatal sepsis in a refugee population on the Thailand Myanmar border.

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    BACKGROUND: Each year an estimated four million neonates die, the majority in the first week of life. One of the major causes of death is sepsis. Proving the incidence and aetiology of neonatal sepsis is difficult, particularly in resource poor settings where the majority of the deaths occur. METHODS: We conducted a three year observational study of clinically diagnosed early onset (<7 days of age) neonatal sepsis (EONS) in infants born to mothers following antenatal care at the Shoklo Malaria Research Unit clinic in Maela camp for displaced persons on the Thailand-Myanmar border. Episodes of EONS were identified using a clinical case definition. Conventional and molecular microbiological techniques were employed in order to determine underlying aetiology. RESULTS: From April 2009 until April 2012, 187 infants had clinical signs of EONS, giving an incidence rate of 44.8 per 1000 live births (95% CI 38.7-51.5). One blood culture was positive for Escherichia coli, E. coli was detected in the cerebrospinal fluid specimen in this infant, and in an additional two infants, by PCR. Therefore, the incidence of bacteriologically proven EONS was 0.7 per 1000 live births (95% CI 0.1-2.1). No infants enrolled in study died as a direct result of EONS. CONCLUSION: A low incidence of bacteriologically proven EONS was seen in this study, despite a high incidence of clinically diagnosed EONS. The use of molecular diagnostics and nonspecific markers of infection need to be studied in resource poor settings to improve the diagnosis of EONS and rationalise antibiotic use
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