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Denitrification from nitrogen-fixing biologically crusted soils in a cool desert environment,southeast Utah,USA

Ecological Processes 2013年第1期2卷 156-164页

作者： Nichole N Barger sarah c castle Gavin N Dean Department of Ecology and Evolutionary Biology University of ColoradoCampus Box 334BoulderCO 80309-0334USA Department of Ecosystem and conservation Sciences College of Forestry and ConservationUniversity of MontanaMissoulaMT59812USA.

Introduction:Nitrogen fixation by microorganisms within biological soil crust(“biocrust”)communities provides an important pathway for N inputs in cool desert environments where soil nutrients are low and symbiotic N-fixing plants may be *** of N fixation in biocrusts often greatly exceed that of N accretion rates leading to uncertainty regarding N loss ***:In this study we examined nitrogen fixation and denitrification rates in biocrust communities that differed in N fixation potential(low N fixation=light cyanobacterial biocrust,high N fixation=dark cyanolichen crust)at four temperature levels(10,20,30,40°c)and four simulated rainfall levels(0.05,0.2,0.6,1 cm rain events)under controlled laboratory ***:Acetylene reduction rates(AR,an index of N fixation activity)were over six-fold higher in dark crusts relative to light *** biocrusts also exhibited eight-fold higher denitrification *** was no consistent effect of temperature on denitrification rates,but there was an interactive effect of water addition and crust *** light crusts,denitrification rates increased with increasing water addition,whereas the highest denitrification rates in dark crusts were observed at the lowest level of water ***:These results suggest that there are no clear and consistent environmental controls on short-term denitrification rates in these biologically crusted *** together,estimates of denitrification from light and dark biocrusts constituted 3 and 4%of N fixation rates,respectively suggesting that losses as denitrification are not significant relative to N inputs via *** estimate is based on a previously published conversion ratio of ethylene produced to N fixed that is low(0.295),resulting in high estimates of N *** future N fixation studies in biologically crusted soils show that these ratios are closer to the theoretical 3:1 ratio,denitrification may constitute a more significant

关键词： Biological soil crust colorado Plateau cool desert Denitrification Nitrogen fixation Soil nitrogen cycling

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Geoengineering Research Moves from Laboratory to Field

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Engineering 2023年第8期27卷 3-5页

作者： sarah c.P.Williams Senior Technology Writer

In March 2023,a converted bomber took off from Eielson Air Force Base in Alaska,USA,carrying a payload of delicate scientific instruments(Fig.1).Operated by the US National Oceanic and Atmospheric Administration(NOAA),the flight aimed to collect a plethora of information about the Earth’s *** exploration sounds routine,but the mission’s goal is unusual for a government entity:to inform policy decisions surrounding large-scale,deliberate interventions to alter the stratosphere for climate change mitigation[1].The approach of deflecting sunlight to cool the planet,called solar radiation management or solar geoengineering,was long considered a fringe *** with recent funding and attention from government agencies like NOAA,the approach is moving mainstream.

关键词： Earth planet payload

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Zika virus and neural developmental defects: building a case for a cause

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Science china(Life Sciences) 2016年第5期59卷 536-538页

作者： sarah c Ogden christy Hammack Hengli Tang Department of Biological Science Florida State University

Zika virus （ZIKV）, a little-known .flavivirus until a few months ago, is currently at the forefront of public health concerns worldwide because of its suspected role in causing microcephaly and other developmental defects in fetuses of infected mothers. On February 1, 2016, the World Health Organization declared a Public Health Emergency of Inter- national concern （PHEIc） for ZIKV. Discovered more than half a century ago in Uganda,

关键词：神经发育病毒缺陷事业世界卫生组织健康问题公共卫生乌干达

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First Pig-to-Live Human Xenotransplant Produces Mixed Results

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Engineering 2022年第9期16卷 6-8页

作者： sarah c.P.Williams Senior Technology Writer

On 7 January 2022,a 57-year-old man with terminal heart disease became the first living human to receive a genetically modified pig organ—a heart—transplanted into his chest during a 8 h surgery at the University of Maryland Medical center in Baltimore,MD,USA(Fig.1)[1].The pig heart,provided by the biotechnology company Revivicor(Blacksburg,VA,USA),had ten gene modifications intended to boost the chances of a successful pig-to-human transplant.

关键词： Maryland Human boost

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cO_2 adsorption using TiO_2 composite polymeric membranes:A kinetic study

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Journal of Environmental Sciences 2015年第9期27卷 163-171页

作者： sarah Hafeez X.Fan Arshad Hussain c.F.Martín School of chemical and Materials Engineering (ScME) National University of Sciences & Technology Institute for Materials and Processes School of Engineering University of Edinburgh University of Aberdeen School of Engineering Fraser Noble Building King's College

cO2is the main greenhouse gas which causes global climatic changes on larger scale. Many techniques have been utilised to capture cO2. Membrane gas separation is a fast growing cO2 capture technique, particularly gas separation by composite membranes. The separation of cO2 by a membrane is not just a process to physically sieve out of cO2 through the controlled membrane pore size. It mainly depends upon diffusion and solubility of gases, particularly for composite dense membranes. The blended components in composite membranes have a high capability to adsorb cO2. The adsorption kinetics of the gases may directly affect diffusion and solubility. In this study, we have investigated the adsorption behaviour of cO2 in pure and composite membranes to explore the complete understanding of diffusion and solubility of cO2 through membranes. Pure cellulose acetate（cA） and cellulose acetatetitania nanoparticle（cA-TiO2） composite membranes were fabricated and characterised using SEM and FTIR analysis. The results indicated that the blended cA-TiO2 membrane adsorbed more quantity of cO2 gas as compared to pure cA membrane. The high cO2 adsorption capacity may enhance the diffusion and solubility of cO2 in the cA-TiO2 composite membrane, which results in a better cO2 separation. The experimental data was modelled by Pseudo first-order, pseudo second order and intra particle diffusion *** to correlation factor R2, the Pseudo second order model was fitted well with experimental data. The intra particle diffusion model revealed that adsorption in dense membranes was not solely consisting of intra particle diffusion.

关键词： Global warming cellulose acetate Gas adsorption Pseudo order models cO2 Ti O2

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Weight stigma mitigating approaches to gender-affirming genital surgery

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Plastic and Aesthetic Research 2022年第1期9卷 295-307页

作者： Elijah castle Gaines Blasdel Nabeel A.Shakir Lee c.Zhao Rachel Bluebond-Langner Department of Urology New York University Langone Medical CenterNew YorkNY 10017USA Vattikuti Urology Institute Henry Ford Health SystemDetroitMI 48202USA Hansjörg Wyss Department of Plastic Surgery New York University Langone Medical CenterNew YorkNY 10017USA

The use of body mass index(BMI)to determine eligibility for gender-affirming surgery in transgender and nonbinary individuals has been *** BMI thresholds are often meant to be protective,restricting patients from access to surgery can also cause *** is a rationale for the continued use of BMI,but the inherent problems with it must also be recognized,including how weight stigma impacts patients’access to gender-affirming surgery and influences clinical *** article uses a narrative review of current literature to discuss how high BMI affects surgical outcomes in gender-affirming genital surgeries,as well as analogous procedures,existing de facto BMI thresholds,and how to both minimize the harms of proceeding with surgery in patients with a high BMI or the harms of delaying for weight *** factors into surgical decision-making based on the existing literature,which demonstrates that high BMI is associated with increased surgical risk,including higher incidences of surgical site infections and poor wound healing,as well as the possibility of free flap complications,which are a component of certain genital *** patient population is at higher risk for eating disorders,and it is prudent to find alternatives to requiring patient self-monitored weight *** impacts of weight stigma should be considered when treating gender-affirming surgery patients,and further data and research are needed to augment shared decision-making and lead to practice change.

关键词： Gender-affirming surgery weight stigma phalloplasty vaginoplasty metoidioplasty body mass index

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The dawn and rise of antimony use in the southern caucasus

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Science china Earth Sciences 2022年第11期65卷 2037-2056页

作者： sarah DILLIS Patrick DEGRYSE Department of Earth and Environmental Sciences Katholieke Universiteit LeuvenCelestjnenlaan 200 EHeverlee 3001Belgium Faculty of Archaeology Leiden UniversityEinsteinweg 2Leiden 2333 CCThe Netherlands

Antimony(Sb)was utilised over several millennia as the prime material to opacify or decolour glass and glazes,as well as an accompanying element in copper(cu)*** antimony objects are rare,and mostly confined to chalcolithic central Italy and to the first millennia BcE in the southern *** innovation of antimony use in metallurgy seems to be confined to the southern caucasus,and the invention of it might be even more specifically situated in the Great *** knowledge of mining set the pathway for the initial stage of antimonial copper alloys in the first half of the third millennium BcE and for metallic antimony ornaments in the second half of the third millennium ***,the first major expansion of antimony in the metallurgy of the Racha-Lechkumi district in the southern caucasus(present-day Georgia)started around 1700 BcE,while its spreading in glassmaking occurred in the Late Bronze Age(LBA).Explanations that place antimony adoption within its broader social context are favoured over those that consider material or geological properties in isolation.A recurring theme is the importance of comparative analysis,both geographically and between the different pyrotechnologies,including the precious metals and glass industries,to explore how social,political,climatic and economic conditions affected adoption and innovation *** these factors are considered to explain why the extraction of antimony blossomed in the Late Bronze Age in the southern caucasus and to reconstruct a framework of exploitation,distribution/trade and use of antimony in the caucasus and its neighbouring regions in the south and east.

关键词： Antimony caucasus Metallurgy Glass Gold

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The origin of uniaxial negative thermal expansion in layered perovskites

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npj computational Materials 2017年第1期3卷 89-96页

作者： chris Ablitt sarah craddock Mark S.Senn Arash A.Mostofi Nicholas c.Bristowe Department of Materials Imperial College LondonLondon SW72AZUK Department of chemistry University of OxfordSouth Parks RoadOxford OX13QRUK Department of chemistry University of WarwickGibbet HillCoventry CV47ALUK Department of Physics Imperial College LondonLondon SW72AZUK School of Physical Sciences University of KentCanterbury CT27NHUK

Why is it that ABO3 perovskites generally do not exhibit negative thermal expansion(NTE)over a wide temperature range,whereas layered perovskites of the same chemical family often do?It is generally accepted that there are two key ingredients that determine the extent of NTE:the presence of soft phonon modes that drive contraction(have negative Grüneisen parameters);and anisotropic elastic compliance that predisposes the material to the deformations required for NTE along a specific *** difference in thermal expansion properties is surprising since both ABO3 and layered perovskites often possess these ingredients in equal measure in their high-symmetry *** first principles calculations and symmetry analysis,we show that in layered perovskites there is a significant enhancement of elastic anisotropy due to symmetry breaking that results from the combined effect of layering and condensed rotations of oxygen *** feature,unique to layered perovskites of certain symmetry,is what allows uniaxial NTE to persist over a large temperature *** fundamental insight means that symmetry and the elastic tensor can be used as descriptors in high-throughput screening and to direct materials design.

关键词： perovskite layered symmetry

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Arsenic variability and groundwater age in three water supply wells in southeast New Hampshire

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Geoscience Frontiers 2019年第5期10卷 1669-1683页

作者： Joseph P.Levitt James R.Degnan sarah M.Flanagan Bryant c.Jurgens U.S.Geological Survey

Three wells in New Hampshire were sampled bimonthly over three years to evaluate the temporal variability of arsenic concentrations and groundwater *** samples had measurable concentrations of arsenic throughout the entire sampling period and concentrations in individual wells had a mean variation of more than 7 μg/*** time series data from this sampling effort showed that arsenic concentrations ranged from a median of 4 mg/L in a glacial aquifer well (SGW-65) to medians of 19 μg/L and 37 μg/L in wells (SGW-93 and KFW-87) screened in the bedrock aquifer,*** high arsenic concentrations were associated with the consistently high pH (median ≥- 8) and low dissolved oxygen (median ck aquifer wells,which is typical of fractured crystalline bedrock aquifers in New *** from the glacial aquifer often has high dissolved oxygen,but in this case was consistently *** pH also is generally acidic in the glacial aquifer but in this case was slightly alkaline (median =7.5).Also,sorption sites may be more abundant in glacial aquifer deposits than in fractured bedrock which may contribute to lower arsenic *** groundwater ages were less than 50 years old in all three wells and correlated with conservative tracer concentrations,such as chloride;however,mean age was not directly correlated with arsenic *** concentrations at KFW-87 did correlate with water levels,in addition,there was a seasonal pattern,which suggests that either the timing of or multiple sampling efforts may be important to define the full range of arsenic concentrations in domestic bedrock *** geochemically reduced conditions and alkaline pHs are common to both bedrock and glacial aquifer wells in this study,groundwater age correlates less strongly with arsenic concentrations than geochemical *** also is evidence of direct hydraulic connection between the glacial and bedrock aquifers,which can influe

关键词： Arsenic variability Geochemical time series Age tracers Groundwater age modeling

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Risk factors of treatment default and death among tuberculosis patients in a resource-limited setting

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Asian Pacific Journal of Tropical Medicine 2014年第12期7卷 977-984页

作者： Isaac Alobu sarah N.Oshi Daniel c.Oshi Kingsley N.Ukwaja National Tuberculosis and Leprosy control Programme Ministry of HealthAbakalikiEbonyi StateNigeria centre for Development and Reproductive Health Enugu.Enugu StateNigeria Department of Internal Medicine Federal Teaching HospitalAbakalikiEbonyi StateNigeria

Objective:To evaluate the rates,timing and determinants of default and death among adult tuberculosis patients in ***:Routine surveillance data were used.A retrospective cohort study of adult tuberculosis patients treated during 2011 and 2012 in two large health facilities in Ebonyi *** was *** logistic regression analyses were used to tdentify independent predictors for treatment default and ***:Of 1668 treated patients,the default rate was 157(9.4%),whilst 165(9.9%) ***,35.7%(56) of the treatment defaults and 151(91.5%) of deaths occurred during the intensive phase of *** of default increased with increasing age(adjusted odds ratio(aOR) 1.2;95%confidence interval(cI)1.1-1.9).smear-negative TB case(aOR 2.3:cI 1.5-3.6).extrapulmonary TB case(aOR 2.7:cI 1.3-5.2).and patients who received the longer treatment regimen(aOR 1,6;1.1-2.2).Risk of death was highest in extrapulmonary TB(aOR 3.0:cI 1.4-6.1) and smear-negative TB cases(aOR 2.4:*** residents(aOR 1.7:cI 1.2-2.6),HIV co-infected(aOR 2.5:cI 1.7-3.6),not receiving antiretroviral therapy(aOR 1.6:cI 1.1-2.9),and not receiving cotrimoxazole prophylaxis(aOR 1.7:cI 1.2—2.6).conclusions:Targeted interventions to improve treatment adherence for patients with the highest risk of default or death are urgently *** needs to he urgently addressed by the National Tuberculosis Programme.

关键词： Tuberculosis Epidemiology Treatment default Mortality Treatment outcome Health services Nigeria

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