4,960 research outputs found
Theodor Billroth and his musical life.
Although most widely recognized for the two types of gastric reconstructions that bear his name, Christian Albert Theodor Billroth was one of the most innovative surgeons of his time. His contributions included developing techniques for procedures on the larynx, breast, and esophagus. He pioneered sterility and antisepsis in operating rooms. He also improved surgical education by advocating for longer apprenticeships, which helped create a framework for today’s residency programs. However, what often goes unnoticed was Dr. Billroth’s love for music, a passion that fueled him throughout his life
Leveraging Contact Network Information in Clustered Randomized Studies of Contagion Processes
In a randomized study, leveraging covariates related to the outcome (e.g.
disease status) may produce less variable estimates of the effect of exposure.
For contagion processes operating on a contact network, transmission can only
occur through ties that connect affected and unaffected individuals; the
outcome of such a process is known to depend intimately on the structure of the
network. In this paper, we investigate the use of contact network features as
efficiency covariates in exposure effect estimation. Using augmented
generalized estimating equations (GEE), we estimate how gains in efficiency
depend on the network structure and spread of the contagious agent or behavior.
We apply this approach to simulated randomized trials using a stochastic
compartmental contagion model on a collection of model-based contact networks
and compare the bias, power, and variance of the estimated exposure effects
using an assortment of network covariate adjustment strategies. We also
demonstrate the use of network-augmented GEEs on a clustered randomized trial
evaluating the effects of wastewater monitoring on COVID-19 cases in
residential buildings at the the University of California San Diego.Comment: Substantial revisio
Canada and the Battle of Vimy Ridge
Public history posters on Canada’s military past about the April 9 - 12, 1917 battle of Vimy Ridge by the Canadian Corps, by students Barry Ho, Maxwell Blair, Elena Melania Panescu, and Patrick Jedrzejkohttps://source.sheridancollege.ca/swfhass_military_posters/1003/thumbnail.jp
World Wind 3D Earth Viewing
World Wind allows users to zoom from satellite altitude down to any place on Earth, leveraging high-resolution LandSat imagery and SRTM (Shuttle Radar Topography Mission) elevation data to experience Earth in visually rich 3D. In addition to Earth, World Wind can also visualize other planets, and there are already comprehensive data sets for Mars and the Earth's moon, which are as easily accessible as those of Earth. There have been more than 20 million downloads to date, and the software is being used heavily by the Department of Defense due to the code s ability to be extended and the evolution of the code courtesy of NASA and the user community. Primary features include the dynamic access to public domain imagery and its ease of use. All one needs to control World Wind is a two-button mouse. Additional guides and features can be accessed through a simplified menu. A JAVA version will be available soon. Navigation is automated with single clicks of a mouse, or by typing in any location to automatically zoom in to see it. The World Wind install package contains the necessary requirements such as the .NET runtime and managed DirectX library. World Wind can display combinations of data from a variety of sources, including Blue Marble, LandSat 7, SRTM, NASA Scientific Visualization Studio, GLOBE, and much more. A thorough list of features, the user manual, a key chart, and screen shots are available at http://worldwind.arc.nasa.gov
Measurements of wake-induced electron beam deflection in a dechirper at the Linac Coherent Light Source
The RadiaBeam/SLAC dechirper, a structure consisting of pairs of flat,
metallic, corrugated plates, %a corrugated structure in flat geometry, has been
installed just upstream of the undulators in the Linac Coherent Light Source
(LCLS). As a dechirper, with the beam passing between the plates on axis,
longitudinal wakefields are induced that can remove unwanted energy chirp in
the beam. However, with the beam passing off axis, strong transverse wakes are
also induced. This mode of operation has already been used for the production
of intense, multi-color photon beams using the Fresh-Slice technique, and is
being used to develop a diagnostic for attosecond bunch length measurements.
Here we measure, as function of offset, the strength of the transverse
wakefields that are excited between the two plates, and also for the case of
the beam passing near to a single plate. We compare with analytical formulas
from the literature, and find good agreement. This report presents the first
systematic measurements of the transverse wake strength in a dechirper, one
that has been excited by a bunch with the short pulse duration and high energy
found in an X-ray free electron laser.Comment: 8 pages, double column, 6 figure
Monitoring the South African National Antiretroviral Treatment Programme, 2003-2007: the IeDEA Southern Africa collaboration.
OBJECTIVES: To introduce the combined South African cohorts of the International epidemiologic Databases to Evaluate AIDS Southern Africa (IeDEA-SA) collaboration as reflecting the South African national antiretroviral treatment (ART) programme; to characterise patients accessing these services; and to describe changes in services and patients from 2003 to 2007. DESIGN AND SETTING: Multi-cohort study of 11 ART programmes in Gauteng, Western Cape, Free State and KwaZulu-Natal. SUBJECTS: Adults and children (<16 years old) who initiated ART with > or =3 antiretroviral drugs before 2008. RESULTS: Most sites were offering free treatment to adults and children in the public sector, ranging from 264 to 17,835 patients per site. Among 45,383 adults and 6,198 children combined, median age (interquartile range) was 35.0 years (29.8-41.4) and 42.5 months (14.7-82.5), respectively. Of adults, 68% were female. The median CD4 cell count was 102 cells/microl (44-164) and was lower among males than females (86, 34-150 v. 110, 50-169, p<0.001). Median CD4% among children was 12% (7-17.7). Between 2003 and 2007, enrolment increased 11-fold in adults and 3-fold in children. Median CD4 count at enrolment increased for all adults (67-111 cells/microl, p<0.001) and for those in stage IV (39-89 cells/microl, p<0.001). Among children <5 years, baseline CD4% increased over time (11.5-16.0%, p<0.001). CONCLUSIONS: IeDEA-SA provides a unique opportunity to report on the national ART programme. The study describes dramatically increased enrolment over time. Late diagnosis and ART initiation, especially of men and children, need attention. Investment in sentinel sites will ensure good individual-level data while freeing most sites to continue with simplified reporting
Evaluation of the Long-Lasting Insecticidal Net Interceptor LN: Laboratory and Experimental Hut Studies against Anopheline and Culicine Mosquitoes in Northeastern Tanzania
Long lasting insecticidal nets (LN) are a primary method of malaria prevention. Before new types of LN are approved they need to meet quality and efficacy standards set by the WHO Pesticide Evaluation Scheme. The process of evaluation has three phases. In Phase I the candidate LN must meet threshold bioassay criteria after 20 standardized washes. In Phase II washed and unwashed LNs are evaluated in experimental huts against wild, free flying anopheline mosquitoes. In Phase III the LN are distributed to households in malaria endemic areas, sampled over three years of use and tested for continuing insecticidal efficacy. Interceptor® LN (BASF Corporation, Germany) is made of polyester netting coated with a wash resistant formulation of alpha-cypermethrin. Interceptor LN was subjected to bioassay evaluation and then to experimental hut trial against pyrethroid-susceptible Anopheles gambiae and An. funestus and resistant Culex quinquefasciatus. Mosquito mortality, blood feeding inhibition and personal protection were compared between untreated nets, conventional alpha-cypermethrin treated nets (CTN) washed 20 times and LNs washed 0, 20 and 30 times. In Phase I Interceptor LN demonstrated superior wash resistance and efficacy to the CTN. In the Phase II hut trial the LN killed 92% of female An. gambiae when unwashed and 76% when washed 20 times; the CTN washed 20 times killed 44%. The LN out-performed the CTN in personal protection and blood-feeding inhibition. The trend for An. funestus was similar to An. gambiae for all outcomes. Few pyrethroid-resistant Cx. quinquefasciatus were killed and yet the level of personal protection (75-90%) against Culex was similar to that of susceptible An. gambiae (76-80%) even after 20 washes. This protection is relevant because Cx. quinquefasciatus is a vector of lymphatic filariasis in East Africa. After 20 washes and 60 nights’ use the LN retained 27% of its initial insecticide dose. Interceptor LN meets the approval criteria set by WHO and is recommended for use in disease control against East African vectors of malaria and filariasis. Some constraints associated with the phase II evaluation criteria, in particular the washing procedure, are critically reviewed
Wearable activity technology and action-planning (WATAAP) to promote physical activity in cancer survivors: Randomised controlled trial protocol
Background/Objective: Colorectal and gynecologic cancer survivors are at cardiovascular risk due to comorbidities and sedentary behaviour, warranting a feasible intervention to increase physical activity. The Health Action Process Approach (HAPA) is a promising theoretical frame-work for health behaviour change, and wearable physical activity trackers offer a novel means of self-monitoring physical activity for cancer survivors.
Method: Sixty-eight survivors of colorectal and gynecologic cancer will be randomised into 12- week intervention and control groups. Intervention group participants will receive: a Fitbit AltaTM to monitor physical activity, HAPA-based group sessions, booklet, and support phone-call. Participants in the control group will only receive the HAPA-based booklet. Physical activity (using accelerometers), blood pressure, BMI, and HAPA constructs will be assessed at baseline, 12-weeks (post-intervention) and 24-weeks (follow-up). Data analysis will use the Group x Time interaction from a General Linear Mixed Model analysis.
Conclusions: Physical activity interventions that are acceptable and have robust theoretical underpinnings show promise for improving the health of cancer survivors
Interceptor® long-lasting insecticidal net: phase III evaluation over three years of household use and calibration with Phase II experimental hut outcomes.
BACKGROUND: Long-lasting insecticidal nets (LN) are an effective tool for malaria prevention. The World Health Organization Pesticide Evaluation Scheme has established evaluation criteria to facilitate registration for public use. A household randomised trial was conducted in Tanzania according to WHOPES Phase III procedures to evaluate the alpha-cypermethrin coated Interceptor® LN (BASF) over three years' use. Outcomes were calibrated against results of Phase II experimental hut trials. METHODS: Interceptor LN (200 mg/m(2) alpha-cypermethrin) and conventionally treated nets CTN (40 mg/m(2) alpha-cypermethrin) were randomly distributed to 934 households. At 6-monthly intervals, household surveys recorded net use, durability, adverse effects, user acceptance and washing practices. Concurrently, 30 nets of each type were collected and tested for knock-down and kill of Anopheles gambiae mosquitoes in cone and tunnel bioassays. Alpha-cypermethrin content of nets was assessed annually. RESULTS: At 12 months 97% of Interceptor LN met the efficacy criteria by cone or tunnel test; this pass rate declined to 90% at 24 months and 87% at 36 months. In contrast only 63% of CTN met the efficacy criteria at 12 months, 14 % at 24 months and 0% at 36 months. The alpha-cypermethrin content at 36 months on Interceptor LN was 20% (42 ± 13 mg/m(2)) of the initial content but on CTNs only 4% (1.3 ± 1.6 mg/m(2)) remained. Interceptor LN was reported to be used year-round and washed 4.3 times/year. A few recalled facial tingling during the first days of use but this did not deter usage. The average number of holes at 36 months was 18, hole area per net was 229 cm(2) and hole index was 332. Insecticide content and cone bioefficacy of LN and CTN after 36 months' use were similar to that of LN and CTN used in earlier Phase II hut trials, but while the 20 times washed LN tested in experimental huts gave adequate personal protection the 20 times washed CTN did not. CONCLUSIONS: More than 80% Interceptor LN fulfilled the WHOPES Phase III criteria at 36 months and thus the LLIN was granted full WHO recommendation. Phase III outcomes at 36 months were anticipated by Phase II outcomes after 20 standardized washes
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