3,577 research outputs found
Sexual networks and HIV in four African populations: the use of a standardised behvioural survey with biological markers
Hydrological Modeling for the Impact of Predicted Climate Change and Urbanization: A Case Study of the Lower Mississippi River Basin
The Mississippi River Basin is the United States’ largest watershed and consists of many subbasins. Each subbasin has hydrological processes including flow rate, evapotranspiration, and groundwater flow. It is important to understand how these processes change through shifts in weather, time, and land use. This study uses the Soil and Water Assessment Tool (SWAT) to predict how changes in temperature, rainfall, and land use can change hydrological processes responses. This study concludes that, for the studied subbasin, a high representative concentration pathway (RCP) will result in lower flow rates and ground water flow as well as higher evapotranspiration by the year 2080. Additionally, as this area becomes urbanized, the average flow rate can be expected to increase by 3.07cms with 106.12cms higher peak flow, the evapotranspiration can be expected to have a peak flow of 1.01mm/day higher, and the average ground water can be expected to drop by 0.85mm/day
Prevention of HIV and other STIs in rural Senegal: a study of prevention-related events collected by sentinel observers
We conducted a study of AIDS/STI prevention-related events based on a network of sentinel observers over a 35-month period in three rural communities of Senegal (May 2000 - March 2003). In one of these communities we also conducted a population-based study on self-reported prevention events and attitudes towards AIDS. Sentinel observers recorded 1 590 AIDS/STI prevention-related events. More than half of the reported events were radio programmes.The proportion of events on the occasion of which therapies was addressed increased significantly between 2000 and 2001, from less than 3% to about 10%, while sharp decreases in the proportion of events dealing with condoms and STIs, both from around 25% to less than 15%, were observed at the same time. The population-based survey indicated that men were more influenced by individual events like informal discussions or radio programmes while women seemed to be more influenced by collective events such as public meetings and school education. Keywords: rural Africa,AIDS/STI prevention-related events, sentinel observers, population-based survey.RÉSUMÉNous avons mené une étude des événements relatifs à la prévention du SIDA et des IST à l\'aide d\'un réseau d\'observateurs-sentinelles sur une durée de 35 mois (mai 2000 - mars 2003) dans trois communautés rurales du Sénégal. Dans l\'une d\'elle, nous avons également conduit en population générale une étude des événements autodéclarés relatifs à la prévention et des attitudes vis-à-vis du SIDA. Les observateurs-sentinelles ont enregistré 1 590 événements. Plus de la moitié concernaient des émissions de radio. La part des événements faisant état des traitements du SIDA a augmenté de 3% à 10% entre 2000 et 2001 alors que celles des événements qui faisaient état du préservatif d\'une part et des IST d\'autre part, ont chuté toutes deux de 25% à 15% sur la même période. L\'enquête en population générale a révélé que les hommes étaient plus influencés par les événements individuels comme les discussion informelles ou les programmes radiodiffusés alors que les femmes semblaient avoir été plus sensibles aux événements collectifs du type réunion publique ou cours donnés à l\'école. Mots clés: Afrique, zone rurale, SIDA/STI, événements relatifs à la prévention, observateurs-sentinelles, enquête en population générale.Journal of Social Aspects of HIV/AIDS, Vol 2(2) 2005: 251-25
Evaluation of International Contemporary Operative Outcomes and Management Trends Associated With Esophagectomy:A 4-Year Study of >6000 Patients Using ECCG Definitions and the Online Esodata Database
OBJECTIVE: This study aims to verify the utility of international online datasets to benchmark and monitor treatment and outcomes in major oncologic procedures. BACKGROUND: The Esophageal Complication Consensus Group (ECCG) has standardized the reporting of complications after esophagectomy within the web-based Esodata.org database. This study will utilize the Esodata dataset to update contemporary outcomes and to monitor trends in practice in an era of rapid technical change. METHODS: This observational study, based on a prospectively developed specific database, updates esophagectomy outcomes collected between 2015 and 2018. Evolution in patient and operative demographics, treatment, complications, and quality outcome measures were compared between patients undergoing surgery in 2015 to 2016 and 2017 to 2018. RESULTS: Between 2015 and 2018, 6022 esophagectomies from 39 centers were entered into Esodata. Most patients were male (78.3%) with median age 63. Patients having minimally invasive esophagectomy constituted 3177 (52.8%), a chest anastomosis 3838 (63.7%), neoadjuvant chemoradiotherapy 2834 (48.7%), and R0 resections 5441 (93.5%). For quality measures, 30- and 90-day mortality was 2.0% and 4.5%, readmissions 9.7%, transfusions 12%, escalation in care 22.1%, and discharge home 89.4%. Trends in quality measures between 2015 and 2016 (2407 patients) and 2017 and 2018 (3318 patients) demonstrated significant (P < 0.05) improvements in readmissions 11.1% to 8.5%, blood transfusions 14.3% to 10.2%, and escalation in care from 24.5% to 20% A significantly (P < 0.05) reduced incidence in pneumonia (15.3%-12.8%) and renal failure (1.0%-0.4%) was observed. Anastomotic leak rates increased from 11.7% to 13.1%, whereas leaks requiring surgery decreased 3.3% and 3.0%, respectively. CONCLUSIONS: The Esodata database provides a valuable resource for assessing contemporary international outcomes. This study highlights an increased application of minimally invasive approaches, a high percentage of complications, improvements in pneumonia and key quality metrics, but with anastomotic leak rates still >10%.</p
Exciton states in monolayer MoSe2: impact on interband transitions
We combine linear and non-linear optical spectroscopy at 4K with ab initio
calculations to study the electronic bandstructure of MoSe2 monolayers. In
1-photon photoluminescence excitation (PLE) and reflectivity we measure a
separation between the A- and B-exciton emission of 220 meV. In 2-photon PLE we
detect for the A- and B-exciton the 2p state 180meV above the respective 1s
state. In second harmonic generation (SHG) spectroscopy we record an
enhancement by more than 2 orders of magnitude of the SHG signal at resonances
of the charged exciton and the 1s and 2p neutral A- and B-exciton. Our
post-Density Functional Theory calculations show in the conduction band along
the direction a local minimum that is energetically and in k-space
close to the global minimum at the K-point. This has a potentially strong
impact on the polarization and energy of the excitonic states that govern the
interband transitions and marks an important difference to MoS2 and WSe2
monolayers.Comment: 8 pages, 3 figure
Lunar laser ranging in infrfared at hte Grasse laser station
For many years, lunar laser ranging (LLR) observations using a green
wavelength have suffered an inhomogeneity problem both temporally and
spatially. This paper reports on the implementation of a new infrared detection
at the Grasse LLR station and describes how infrared telemetry improves this
situation. Our first results show that infrared detection permits us to densify
the observations and allows measurements during the new and the full Moon
periods. The link budget improvement leads to homogeneous telemetric
measurements on each lunar retro-reflector. Finally, a surprising result is
obtained on the Lunokhod 2 array which attains the same efficiency as Lunokhod
1 with an infrared laser link, although those two targets exhibit a
differential efficiency of six with a green laser link
Atmospheric parameters and chemical properties of red giants in the CoRoT asteroseismology fields
A precise characterisation of the red giants in the seismology fields of the
CoRoT satellite is a prerequisite for further in-depth seismic modelling.
High-resolution FEROS and HARPS spectra were obtained as part of the
ground-based follow-up campaigns for 19 targets holding great asteroseismic
potential. These data are used to accurately estimate their fundamental
parameters and the abundances of 16 chemical species in a self-consistent
manner. Some powerful probes of mixing are investigated (the Li and CNO
abundances, as well as the carbon isotopic ratio in a few cases). The
information provided by the spectroscopic and seismic data is combined to
provide more accurate physical parameters and abundances. The stars in our
sample follow the general abundance trends as a function of the metallicity
observed in stars of the Galactic disk. After an allowance is made for the
chemical evolution of the interstellar medium, the observational signature of
internal mixing phenomena is revealed through the detection at the stellar
surface of the products of the CN cycle. A contamination by NeNa-cycled
material in the most massive stars is also discussed. With the asteroseismic
constraints, these data will pave the way for a detailed theoretical
investigation of the physical processes responsible for the transport of
chemical elements in evolved, low- and intermediate-mass stars.Comment: Accepted for publication in A&A, 25 pages, 13 colour figures (revised
version after language editing
Dark-bright mixing of interband transitions in symmetric semiconductor quantum dots
In photoluminescence spectra of symmetric [111] grown GaAs/AlGaAs quantum
dots in longitudinal magnetic fields applied along the growth axis we observe
in addition to the expected bright states also nominally dark transitions for
both charged and neutral excitons. We uncover a strongly non-monotonous, sign
changing field dependence of the bright neutral exciton splitting resulting
from the interplay between exchange and Zeeman effects. Our theory shows
quantitatively that these surprising experimental results are due to
magnetic-field-induced \pm 3/2 heavy-hole mixing, an inherent property of
systems with C_3v point-group symmetry.Comment: 5 pages, 3 figure
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