1,738 research outputs found
Water balance complexities in ephemeral catchments with different land uses: Insights from monitoring and distributed hydrologic modeling
Although ephemeral catchments are widespread in arid and semiarid climates, the relationship of their water balance with climate, geology, topography, and land cover is poorly known. Here we use 4 years (2011â2014) of rainfall, streamflow, and groundwater level measurements to estimate the water balance components in two adjacent ephemeral catchments in south-eastern Australia, with one catchment planted with young eucalypts and the other dedicated to grazing pasture. To corroborate the interpretation of the observations, the physically based hydrological model CATHY was calibrated and validated against the data in the two catchments. The estimated water balances showed that despite a significant decline in groundwater level and greater evapotranspiration in the eucalypt catchment (104â119% of rainfall) compared with the pasture catchment (95â104% of rainfall), streamflow consistently accounted for 1â4% of rainfall in both catchments for the entire study period. Streamflow in the two catchments was mostly driven by the rainfall regime, particularly rainfall frequency (i.e., the number of rain days per year), while the downslope orientation of the plantation furrows also promoted runoff. With minimum calibration, the model was able to adequately reproduce the periods of flow in both catchments in all years. Although streamflow and groundwater levels were better reproduced in the pasture than in the plantation, model-computed water balance terms confirmed the estimates from the observations in both catchments. Overall, the interplay of climate, topography, and geology seems to overshadow the effect of land use in the study catchments, indicating that the management of ephemeral catchments remains highly challenging
Plant Poisons in the Garden: A Human Risk Assessment
A study of the plants, and their associated poisons, in the Poison Garden at The Alnwick Garden was undertaken across a calendar year. By selecting 25 plants in the Poison Garden, we have been able to develop a single chromatographic method for the determination and quantification of 15 plant toxins by liquid chromatography mass spectrometry (LC-MS). Chromatographic separation was achieved on a C18 column (3.5 ”m, 100 à 4.6 mm) with a gradient method using water +0.1 formic acid and methanol +0.1 formic acid. The developed method was validated for precision, linearity, limits of detection and quantification and extraction recoveries. The method showed good linearity with a R2 value of >0.995 for all 15 compounds with good precision of 10.7, 6.7 and 0.3 for the low, medium and high calibration points, respectively. The LC-MS method was used to analyse 25 plant species, as well as their respective parts (i.e., bulb, flower, fruit, leaf, pollen, seed, stem and root), to assess the human risk assessment to children (aged 1 to <2 years) in relation to the plant toxin and its respective LD50. The analysis found that the greatest potential health risks were due to the ingestion of Colchicum autumnale and Atropa belladonna. As a caution, all identified plants should be handled with care with additional precautionary steps to ensure nil contact by children because of the potential likelihood of hand-to-mouth ingestion
Forensic profiling of smokeless powders (SLPs) by gas chromatographyâmass spectrometry (GC-MS): a systematic investigation into injector conditions and their effect on the characterisation of samples
Smokeless powders (SLPs) are composed of a combination of thermolabile and non-thermolabile compounds. When analysed by GC-MS, injection conditions may therefore play a fundamental role on the characterisation of forensic samples. However, no systematic investigations have ever been carried out. This casts doubt on the optimal conditions that should be adopted in advanced profiling applications (e.g. class attribution and source association), especially when a traditional split/splitless (S/SL) injector is used. Herein, a study is reported that specifically focused on the evaluation of the liner type (L type) and inlet temperature (T inj). Results showed that both could affect the exhaustiveness and repeatability of the observed chemical profiles, with L type being particularly sensitive despite typically not being clarified in published works. Perhaps as expected, degradation effects were observed for the most thermolabile compounds (e.g. nitroglycerin) at conditions maximising the heat transfer rates (L type = packed and T inj ℠200 °C). However, these did not seem to be as influential as, perhaps, suggested in previous studies. Indeed, the harshest injection conditions in terms of heat transfer rate (L type = packed and T inj = 260 °C) were found to lead to better performances (including better overall %RSDs and LODs) compared to the mildest ones. This suggested that implementing conditions minimising heat-induced breakdowns during injection was not necessarily a good strategy for comparison purposes. The reported findings represent a concrete step forward in the field, providing a robust body of data for the development of the next generation of SLP profiling methods. Graphical abstract: (Figure presented.).</p
Genetic sequencing for surveillance of drug resistance in tuberculosis in highly endemic countries: A multi-country population-based surveillance study
Background: In many countries, regular monitoring of the emergence of resistance to anti-tuberculosis drugs is hampered by the limitations of phenotypic testing for drug susceptibility. We therefore evaluated the use of genetic sequencing for surveillance of drugresistance in tuberculosis.Methods: Population-level surveys were done in hospitals and clinics in seven countries (Azerbaijan, Bangladesh, Belarus, Pakistan, Philippines, South Africa, and Ukraine) to evaluate the use of genetic sequencing to estimate the resistance of Mycobacterium tuberculosisisolates to rifampicin, isoniazid, ofloxacin, moxifloxacin, pyrazinamide, kanamycin, amikacin, and capreomycin. For each drug, we assessed the accuracy of genetic sequencing by a comparison of the adjusted prevalence of resistance, measured by genetic sequencing, with the true prevalence of resistance, determined by phenotypic testing.Findings: Isolates were taken from 7094 patients with tuberculosis who were enrolled in the study between November, 2009, and May, 2014. In all tuberculosis cases, the overall pooled sensitivity values for predicting resistance by genetic sequencing were 91% (95% CI 87-94) for rpoB (rifampicin resistance), 86% (74-93) for katG, inhA, and fabG promoter combined (isoniazid resistance), 54% (39-68) for pncA (pyrazinamide resistance), 85% (77-91) for gyrA and gyrB combined (ofloxacin resistance), and 88% (81-92) for gyrA and gyrB combined (moxifloxacin resistance). For nearly all drugs and in most settings, there was a large overlap in the estimated prevalence of drug resistanceby genetic sequencing and the estimated prevalence by phenotypic testing.Interpretation: Genetic sequencing can be a valuable tool for surveillance of drug resistance, providing new opportunities to monitor drug resistance in tuberculosis in resource-poor countries. Before its widespread adoption for surveillance purposes, there is a need to standardise DNA extraction methods, recording and reporting nomenclature, and data interpretation.Findings: Bill & Melinda Gates Foundation, United States Agency for International Development, Global Alliance for Tuberculosis DrugDevelopment
Management interventions for amputation stump neuromas : evidence based review and cost-benefit analysis
Amputation is a common military and civilian surgery with high morbidity. Patients without prostheses
due to neuroma pain lose productivity and lifelong contributions, which is often underestimated. The
surgical and non-surgical treatment of painful stump neuromas is controversial. An evidence-based assessment and cost-benefit analysis of painful stump neuroma management modalities emphasizes institutional awareness and disruptive technologies. An Oxford Centre for Evidence Based Methodology
critical appraisal and structured literature review were used in the research. We found 154 records using
a reproducible literature search strategy that included electronic databases and references. A full review
of 27 manuscripts after exclusion criteria yielded data for analysis. Surgical, injectable, and electromagnetic spectrum methods were used. Surgical interventions had longer follow-up times than injection and
radiofrequency treatments, which affected outcomes. CEBM level 4 evidence dominated primary literature, indicating low quality. No therapy was superior, but the risks varied. Injection therapies like sclerosing alcohol had limited success and side effects. Despite limited evidence, electromagnetic spectrum
modalities showed potential. Including direct and indirect costs, amputation stump refitting costs millions annually. Compared to outpatient non-surgical interventions, laser therapy could save a lot of
money. According to the study, surgical interventions are common but expensive and have limited functional success. Low-risk non-surgical methods like co-ablation, pulsed radiofrequency, and transcutaneous
laser therapy have mixed results. The short follow-up of all non-surgical studies seems to limit them.
Follow-up duration is crucial to outcome assessment. Long-term, low-risk laser-induced thermotherapy
is promising for future research. This study emphasizes the need for more research and the economic
benefits of disruptive technologies in treating painful stump neuromas.peer-reviewe
VLT-UVES abundance analysis of four giants in NGC 6553
Metal-rich globular clusters trace the formation of bulges. Abundance ratios
in the metal-rich globular clusters such as NGC 6553 can constrain the
formation timescale of the Galactic bulge. The purpose of this study is
determine the metallicity and elemental ratios in individual stars of the
metal-rich bulge globular cluster NGC 6553. A detailed abundance analysis of
four giants in NGC 6553 is carried out, based on optical high-resolution
echelle spectra obtained with UVES at the ESO VLT-UT2 Kueyen telescope. A
metallicity [Fe/H]= -0.20 dex is derived, together with -element
enhancement of Mg and Si ([Mg/Fe]=+0.28, [Si/Fe]=+0.21), solar Ca and Ti
([Ca/Fe]=+0.05, [Ti/Fe]=-0.01), and a mild enhancement of the r-process element
Eu with [Eu/Fe] = +0.10. A mean heliocentric radial velocity of -1.86 km
s is measured. We compare our results with previous investigations of
the cluster.Comment: 15 pages, 8 figures, A&A, in pres
Paramagnon dispersion and damping in doped NaCaCuOCl
Using Resonant Inelastic X-ray Scattering, we measure the paramagnon
dispersion and damping of undoped, antiferromagnetic CaCuOCl as
well as doped, superconducting NaCaCuOCl. Our estimation
of the spin-exchange parameter and width of the paramagnon peak at the zone
boundary confirms that no simple relation can be drawn between
these parameters and the critical temperature . Consistently with
other cuprate compounds, we show that upon doping there is a slight softening
at , but not at the zone boundary . In combination with these
measurements we perform calculations of the dynamical spin structure factor of
the one-band Hubbard model using cluster dynamical mean-field theory. The
calculations are in excellent agreement with the experiment in the undoped
case, both in terms of energy position and width. While the increase in width
is also captured upon doping, the dynamical spin structure factor shows a
sizable softening at , which provides insightful information on the
length-scale of the spin fluctuations in doped cuprates.Comment: 11 pages, 5 figures, 2 tables, V2 typo corrected in title and
reference
Ongoing challenges to understanding multidrug- and rifampicin-resistant tuberculosis in children versus adults.
Previous analyses suggest that children with tuberculosis (TB) are no more or no less likely to have multidrug (MDR)- or rifampicin-resistant (RR)-TB than adults. However, the availability of new data, particularly for high MDR/RR-TB burden countries, suggest updates of country-specific estimates are warranted.We used data from population-representative surveys and surveillance collected between 2000 and 2018 to compare the odds ratio of MDR/RR-TB among children (aged <15 years) with TB, compared to the odds of MDR/RR-TB among adults (aged â„15 years) with TB.In most settings (45 out of 55 countries), and globally as a whole, there is no evidence that age is associated with odds of MDR/RR-TB. However, in some settings, such as former Soviet Union countries in general, and Georgia, Kazakhstan, Lithuania, Tajikistan and Uzbekistan in particular, as well as Peru, MDR/RR-TB is positively associated with age â„15 years. Meanwhile, in Western Europe in general, and the United Kingdom, Poland, Finland and Luxembourg in particular, MDR/RR-TB is positively associated with age <15 years. 16 countries had sufficient data to compare over time between 2000-2011 and 2012-2018, with evidence for decreases in the odds ratio in children compared to adults in Germany, Kazakhstan and the United States of America.Our results support findings that in most settings a child with TB is as likely as an adult with TB to have MDR/RR-TB. However, setting-specific heterogeneity requires further investigation. Furthermore, the odds ratio for MDR/RR-TB in children compared to adults is generally either stable or decreasing. There are important gaps in detection, recording and reporting of drug resistance among paediatric TB cases, limiting our understanding of transmission risks and measures needed to combat the global TB epidemic
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