1,995 research outputs found
Near-Infrared Kinetic Spectroscopy of the HO_2 and C_2H_5O_2 Self-Reactions and Cross Reactions
The self-reactions and cross reactions of the peroxy radicals HO_2 and C_2H_5O_2 and HO_2 were monitored using simultaneous independent spectroscopic probes to observe each radical species. Wavelength modulation (WM) near-infrared (NIR) spectroscopy was used to detect HO_2, and UV absorption monitored HO_2 and C_2H_5O_2. The temperature dependences of these reactions were investigated over a range of interest to tropospheric chemistry, 221â296 K. The Arrhenius expression determined for the cross reaction, k_2(T) = (6.01^(+1.95)_(â1.47)) Ă 10^(â13) exp((638 ± 73)/T) cm^3 molecules^(â1) s^(â1) is in agreement with other work from the literature. The measurements of the HO_2 self-reaction agreed with previous work from this lab and were not further refined.(1) The C_2H_5O_2 self-reaction is complicated by secondary production of HO_2. This experiment performed the first direct measurement of the self-reaction rate constant, as well as the branching fraction to the radical channel, in part by measurement of the secondary HO_2. The Arrhenius expression for the self-reaction rate constant is k_3(T) = (1.29^(+0.34)_(â0.27)) Ă 10^(â13)exp((â23 ± 61)/T) cm^3 molecules^(â1) s^(â1), and the branching fraction value is α = 0.28 ± 0.06, independent of temperature. These values are in disagreement with previous measurements based on end product studies of the branching fraction. The results suggest that better characterization of the products from RO_2 self-reactions are required
Development and Characterisation of a Gas System and its Associated Slow-Control System for an ATLAS Small-Strip Thin Gap Chamber Testing Facility
A quality assurance and performance qualification laboratory was built at
McGill University for the Canadian-made small-strip Thin Gap Chamber (sTGC)
muon detectors produced for the 2019-2020 ATLAS experiment muon spectrometer
upgrade. The facility uses cosmic rays as a muon source to ionise the quenching
gas mixture of pentane and carbon dioxide flowing through the sTGC detector. A
gas system was developed and characterised for this purpose, with a simple and
efficient gas condenser design utilizing a Peltier thermoelectric cooler (TEC).
The gas system was tested to provide the desired 45 vol% pentane concentration.
For continuous operations, a state-machine system was implemented with alerting
and remote monitoring features to run all cosmic-ray data-acquisition
associated slow-control systems, such as high/low voltage, gas system and
environmental monitoring, in a safe and continuous mode, even in the absence of
an operator.Comment: 23 pages, LaTeX, 14 figures, 4 tables, proof corrections for Journal
of Instrumentation (JINST), including corrected Fig. 8b
Pre-calving intravaginal administration of lactic acid bacteria reduces metritis prevalence and regulates blood neutrophil gene expression after calving in dairy cattle
Metritis affects up to 40% of dairy cows and it is usually treated with antibiotics. In
spite of their advantages, there is an increased concern about antibiotic resistance
leading to the research of alternative methods. The aim of this study was to evaluate
the effects of a combination of lactic acid bacteria (LAB) on the prevalence of metritis
and modulation of endometrial and neutrophil inflammatory markers in dairy cows. One
hundred and thirty-five cows were enrolled 3 week before calving and randomly assigned
to three treatments. Treatment groups were: (1) two intravaginal doses of LAB/wk during
3 week pre-calving (vaginal, n = 45); (2) an intra-uterine dose, once 1 d after calving
(uterine, n = 44); and (3) no intervention (CTRL, n = 45). Metritis was defined as body
temperature > 39.5âŠC and purulent vaginal discharge (> 50% pus), and diagnosed
6 d after calving. Blood samples were taken at d â14, â10, â7, â4, +1, +3, +6,
and +14 relative to calving for non-esterified fatty acids (NEFA) analysis. At d â10,
+1, +3, and +6 neutrophils were isolated from blood for gene expression analysis
by RT-qPCR. Endometrium biopsies were taken from 30 cows, 15 from CTRL and 15
from the uterine group at d +1, +3, and +6 after calving for pro-inflammatory markers
analysis by NanoStringÂź. Vaginal treatment reduced metritis prevalence (6/45) up to
58% compared with CTRL group (14/45), but there was no difference between the
uterine and CTRL group. Uterine and vaginal treatments reduced blood neutrophil gene
expression. Expression of pro-inflammatory markers in the endometrium did not differ
between uterine and CTRL cows. Metritic cows expressed more C-X-C motif chemokine
ligand 8 (CXCL8) and interleukin 1 beta (IL1B) at d 3 than healthy cows, whereas healthy
cows expressed more CXCL8 at d 1 relative to calving in the endometrium. This study
shows a promising potential of LAB probiotics as a preventive treatment against metritis
in dairy cows.info:eu-repo/semantics/publishedVersio
Designing tools to predict and mitigate impacts on water quality following the Australian 2019/2020 wildfires: Insights from Sydney's largest water supply catchment
The 2019/20 Australian bushfires (or wildfires) burned the largest forested area in Australia's recorded history, with major socioâeconomic and environmental consequences. Among the largest fires was the 280,000 ha Green Wattle Creek Fire which burned large forested areas of the Warragamba catchment. This protected catchment provides critical ecosystem services for Lake Burragorang, one of Australia's largest urban supply reservoirs delivering ~85 % of the water used in Greater Sydney. WaterNSW is the utility responsible for managing water quality in Lake Burragorang. Its postfire risk assessment, carried out in collaboration with researchers in Australia, the UK and USA, involved i) identifying pyrogenic contaminants in ash and soil; ii) quantifying ash loads and contaminant concentrations across the burned area; and iii) estimating the probability and quantity of soil, ash and associated contaminants entrainment for different rainfall scenarios. The work included refining the capabilities of the new WEPPcloudâWATARâAU model (Water Erosion Prediction Project cloudâWildfire Ash Transport And RiskâAustralia) for predicting sediment, ash and contaminants transport, aided by outcomes from previous collaborative postâfire research in the catchment. Approximately two weeks after the Green Wattle Creek Fire was contained, an extreme rainfall event (~276 mm in 72 h), caused extensive ash and sediment delivery into the reservoir. The risk assessment informed onâground monitoring and operational mitigation measures (deployment of debrisâcatching booms and adjustment of the water supply system configuration), ensuring the continuity of safe water supply to Sydney. WEPPcloudâWATARâAU outputs can prioritize recovery interventions for managing water quality risks by quantifying contaminants on the hillslopes, anticipating water contamination risk, and identifying areas with high susceptibility to ash and sediment transport. This collaborative interaction among scientists and water managers, aimed also at refining model capabilities and outputs to meet managersâ needs, exemplifies the successful outcomes that can be achieved at the interface of industry and science
Targeting serine hydroxymethyltransferases 1 and 2 for T-cell acute lymphoblastic leukemia therapy
Despite progress in the treatment of acute lymphoblastic leukemia (ALL), T-cell ALL (T-ALL) has limited treatment options, particularly in the setting of relapsed/refractory disease. Using an unbiased genome-scale CRISPR-Cas9 screen we sought to identify pathway dependencies for T-ALL which could be harnessed for therapy development. Disruption of the one-carbon folate, purine and pyrimidine pathways scored as the top metabolic pathways required for T-ALL proliferation. We used a recently developed inhibitor of SHMT1 and SHMT2, RZ-2994, to characterize the effect of inhibiting these enzymes of the one-carbon folate pathway in T-ALL and found that T-ALL cell lines were differentially sensitive to RZ-2994, with the drug inducing a S/G2 cell cycle arrest. The effects of SHMT1/2 inhibition were rescued by formate supplementation. Loss of both SHMT1 and SHMT2 was necessary for impaired growth and cell cycle arrest, with suppression of both SHMT1 and SHMT2 inhibiting leukemia progression in vivo. RZ-2994 also decreased leukemia burden in vivo and remained effective in the setting of methotrexate resistance in vitro. This study highlights the significance of the one-carbon folate pathway in T-ALL and supports further development of SHMT inhibitors for treatment of T-ALL and other cancers
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Wind Power on Native American Lands: Opportunities, Challenges, and Status (Poster)
The United States is home to more than 700 American Indian tribes and Native Alaska villages and corporations located on 96 million acres. Many of these tribes and villages have excellent wind resources that could be commercially developed to meet their electricity needs or for electricity export. This conference poster for Windpower 2007 describes the opportunities, challenges, and status of wind energy projects on Native American lands in the United States
Measurement of B(Ds+ -->ell+ nu) and the Decay Constant fDs From 600/pb of e+e- Annihilation Data Near 4170 MeV
We examine e+e- --> Ds^-D_s^{*+} and Ds^{*-}Ds^{+} interactions at 4170 MeV
using the CLEO-c detector in order to measure the decay constant fDs with good
precision. Previously our measurements were substantially higher than the most
precise lattice based QCD calculation of (241 +/- 3) MeV. Here we use the D_s^+
--> ell^+ nu channel, where the ell^+ designates either a mu^+ or a tau^+, when
the tau^+ --> pi^+ anti-nu. Analyzing both modes independently, we determine
B(D_s^+ --> mu^+ nu)= 0.565 +/- 0.045 +/- 0.017)%, and B(D_s^+ --> mu^+ nu)=
(6.42 +/- 0.81 +/- 0.18)%. We also analyze them simultaneously to find an
effective value of B^{eff}(D_s^+ --> mu^+ nu)= (0.591 +/- 0.037 +/- 0.018)% and
fDs=(263.3 +/- 8.2 +/- 3.9) MeV. Combining with the CLEO-c value determined
independently using D_s^+ --> tau^+ nu, tau^+ --> e^+ nu anti-nu decays, we
extract fDs=(259.5 +/- 6.6 +/- 3.1) MeV. Combining with our previous
determination of B(D^+ --> mu^+ nu), we extract the ratio fDs/fD+=1.26 +/- 0.06
+/- 0.02. No evidence is found for a CP asymmetry between Gamma(D_s^+ -->
mu^+\nu) and \Gamma(D_s^- --> mu^- nu); specifically the fractional difference
in rates is measured to be (4.8 +/- 6.1)%. Finally, we find B(D_s^+ --> e^+ nu)
< 1.2x10^{-4} at 90% confidence level.Comment: 26 pages, 16 figure
Achieving sustainable construction within Private Finance Initiative (PFI) road projects in the UK
The construction industry is facing the challenge of increasing demands of its sustainability performance. The construction and maintenance of the built environment has substantial impact on the sustainability of the environment. Whist, public sector clients are increasingly asking for a sustainable approach in their specification and procurement decisions, sustainability is still seen as a novel concept within the construction industry in many parts of the world without a settled definition. The premise of this study is that the interaction between road projects realized by the private finance initiative and their delivery in the UK improve sustainability. The paper, based on case study research, explains the sustainability implementation in a PFI road project and demonstrates that the PFI mechanism facilitates sustainable implementation to a far greater extent than is achievable using traditional procurement methods
Inclusive jet cross sections and dijet correlations in photoproduction at HERA
Inclusive jet cross sections in photoproduction for events containing a
meson have been measured with the ZEUS detector at HERA using an integrated
luminosity of . The events were required to have a
virtuality of the incoming photon, , of less than 1 GeV, and a
photon-proton centre-of-mass energy in the range . The measurements are compared with next-to-leading-order (NLO) QCD
calculations. Good agreement is found with the NLO calculations over most of
the measured kinematic region. Requiring a second jet in the event allowed a
more detailed comparison with QCD calculations. The measured dijet cross
sections are also compared to Monte Carlo (MC) models which incorporate
leading-order matrix elements followed by parton showers and hadronisation. The
NLO QCD predictions are in general agreement with the data although differences
have been isolated to regions where contributions from higher orders are
expected to be significant. The MC models give a better description than the
NLO predictions of the shape of the measured cross sections.Comment: 43 pages, 12 figures, charm jets ZEU
Reconceptualizing conservation
Early definitions of conservation focused largely on the end goals of protection or restoration of nature, and the various disciplinary domains that contribute to these ends. Conservation science and practice has evolved beyond being focused on just issues of scarcity and biodiversity decline. To better recognize the inherent links between human behaviour and conservation, âsuccessâ in conservation is now being defined in terms that include human rights and needs. We also know that who engages in conservation, and how, dictates the likelihood that conservation science will be embraced and applied to yield conservation gains. Here we present ideas for reconceptualizing conservation. We emphasize the HOW in an attempt to reorient and repurpose the term in ways that better reflect what contemporary conservation is or might aspire to be. To do so, we developed an acrostic using the letters in the term âCONSERVATIONâ with each serving as an adjective where C = co-produced, O = open, N = nimble, S = solutions-oriented, E = empowering, R = relational, V = values-based, A = actionable, T = transdisciplinary, I = inclusive, O = optimistic, and N = nurturing. For each adjective, we briefly describe our reasoning for its selection and describe how it contributes to our vision of conservation. By reconceptualizing conservation we have the potential to center how we do conservation in ways that are more likely to result in outcomes that benefit biodiversity while also being just, equitable, inclusive, and respectful of diverse rights holders, knowledge holders, and other actors. We hope that this acrostic will be widely adopted in training to help the next generation of conservation researchers and practitioners keep in mind what it will take to make their contributions effective and salient
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