4,025 research outputs found
Variation in annual volume at a university hospital does not predict mortality for pancreatic resections.
Annual volume of pancreatic resections has been shown to affect mortality rates, prompting recommendations to regionalize these procedures to high-volume hospitals. Implementation has been difficult, given the paucity of high-volume centers and the logistical hardships facing patients. Some studies have shown that low-volume hospitals achieve good outcomes as well, suggesting that other factors are involved. We sought to determine whether variations in annual volume affected patient outcomes in 511 patients who underwent pancreatic resections at the University of California, San Francisco between 1990 and 2005. We compared postoperative mortality and complication rates between low, medium, or high volume years, designated by the number of resections performed, adjusting for patient characteristics. Postoperative mortality rates did not differ between high volume years and medium/low volume years. As annual hospital volume of pancreatic resections may not predict outcome, identification of actual predictive factors may allow low-volume centers to achieve excellent outcomes
Electronic Properties of Strained Si/Ge Core-Shell Nanowires
We investigated the electronic properties of strained Si/Ge core-shell
nanowires along the [110] direction using first principles calculations based
on density-functional theory. The diameter of the studied core-shell wire is up
to 5 nm. We found the band gap of the core-shell wire is smaller than that of
both pure Si and Ge wires with the same diameter. This reduced band gap is
ascribed to the intrinsic strain between Ge and Si layers, which partially
counters the quantum confinement effect. The external strain is further applied
to the nanowires for tuning the band structure and band gap. By applying
sufficient tensile strain, we found the band gap of Si-core/Ge-shell nanowire
with diameter larger than ~3 nm experiences a transition from direct to
indirect gap.Comment: 4 figure
Challenges and Opportunities to Improve Tuberculosis Screening Among Immigrant Plantation Workers in Sabah, Malaysia
Tuberculosis (TB) among immigrants has substantial contribution to the TB epidemiology in Sabah. This study aimed to determine the yield of screening for TB disease among immigrant plantation workers in Sabah, Malaysia. This was a prospective cohort study involving 482 legal immigrant workers aged 18 years and above, consented and available at study sites during the study period. Workers with previous history of TB or currently on TB treatment were excluded from participation. Symptom based questionnaire was administered along with both chest radiograph and sputum samples collection for symptomatics participants. Out of 482 plantation workers creened, there was no case of active TB detected among the 44 (9.1%) symptomatics participants. Finding of low TB yield in this study was rather unexpected but this indicates the real challenges for the local health authority to come out with more cost effective screening programs, including reducing stigma, in active TB screening among migrant population
Assessing the readiness of contractors in implementing low carbon construction in Penang
Global warming or climate change is becoming the main concerns of humanity as it leads to an increase in Earth’s temperature and rise in the oceans’ level which is due to the increase of greenhouse gasses in the atmosphere. Greenhouse gasses consists of water vapour, carbon dioxide (CO2), methane (CH4), nitrous oxide (N20), tropospheric ozone (O3) and chlorofluorocarbons (CFCs). Among the gasses, CO2 is the highest and easiest gas to measure as it is emitted from human economic activities with construction industry one of the major contributors of carbon emissions. Low carbon construction is the reduction of carbon emissions from the construction activities during construction process. For the implementation of low carbon construction in our construction industry, the contractors need to be ready and have knowledge to adopt low carbon construction industry. The purpose of this research is to determine the level of contractors’ knowledge towards low carbon construction, determining the level of readiness towards low carbon construction and proposing a checklist for the contractors towards low carbon construction in Penang. This research employed questionnaire survey to analyse the level of knowledge and readiness of the contractors on low carbon construction. As a conclusion, the implementation of low carbon practices by the contractors in Penang is good, therefore established that G7 contractors implement low carbon practices throughout their construction. However, the results and findings indicated that the average mean score on the level of readiness of contractors towards low carbon construction is 3.59. The result was perceived as moderate. Therefore, it shows that the contractors are in a moderate readiness to implement low carbon construction fully in their construction projects. A checklist was established by summarizing the highest low carbon activities from each category which were sustainable site planning and management, materials and resources, waste management, water efficiency and energy efficiency, and was perceived as good. Keywords: Climate change, greenhouse gases, carbon emission, low carbon construction, contractors’ readiness
Hanbury Brown and Twiss Interferometry with Twisted Light
The rich physics exhibited by random optical wave fields permitted Hanbury
Brown and Twiss to unveil fundamental aspects of light. Furthermore, it has
been recognized that optical vortices are ubiquitous in random light and that
the phase distribution around these optical singularities inprints a spectrum
of orbital angular momentum onto a light field. We demonstrate that random
fluctuations of light give rise to the formation of correlations in the orbital
angular momentum components and angular positions of pseudothermal light. The
presence of these correlations is manisfested through distinct interference
structures in the orbital angular momentum-mode distribution of random light.
These novel forms of interference correspond to the azimuthal analog of the
Hanbury Brown and Twiss effect. This family of effects can be of fundamental
importance in applications where entanglement is not required and where
correlations in angular position and orbital angular momentum suffice. We also
suggest that the azimuthal Hanbury Brown and Twiss effect can be useful in the
exploration of novel phenomena in other branches of physics and astrophysics.Comment: Science Advance
Scaling in many-body systems and proton structure function
The observation of scaling in processes in which a weakly interacting probe
delivers large momentum to a many-body system simply reflects the
dominance of incoherent scattering off target constituents. While a suitably
defined scaling function may provide rich information on the internal dynamics
of the target, in general its extraction from the measured cross section
requires careful consideration of the nature of the interaction driving the
scattering process. The analysis of deep inelastic electron-proton scattering
in the target rest frame within standard many-body theory naturally leads to
the emergence of a scaling function that, unlike the commonly used structure
functions and , can be directly identified with the intrinsic proton
response.Comment: 11 pages, 4 figures. Proceedings of the 11th Conference on Recent
Progress in Many-Body Theories, Manchester, UK, July 9-13 200
The Debt-Equity Ratio Choice: Risk Sharing Instruments, a Viable Alternative
Evidence has been documented in the literature that the interest based debt financing system is experiencing continuous discomfort. The outcome of the 2008 global financial crisis has further create fresh vigor to the assertion. Also, these authors have submitted that debt and leveraging are the two major causes of financial instability in the present system. This paper claims that the existence of the interest-based debt regime is becoming less acceptable, as excessive debt can affect the whole economic system, even in a developed country like United States. From an economic viewpoint, therefore, by banning interest rate-based contracts and decreeing exchange contracts, Islamic financeinspires risk sharing and prohibits risk transfer, risk shedding, and risk shifting. The paper proposes risk sharing based Islamic financing as a suitable alternative to the interest based debt financing. This study concludes that risk-sharing finance has several benefits, especially its potential to minimize, if not circumvent, the debt prompted financial crises that have beset the world.
Assessment of the Risks of Mixtures of Major Use Veterinary Antibiotics in European Surface Waters
Effects of single veterinary antibiotics on a range of aquatic organisms have been explored in many studies. In reality, surface waters will be exposed to mixtures of these substances. In this study, we present an approach for establishing risks of antibiotic mixtures to surface waters and illustrate this by assessing risks of mixtures of three major use antibiotics (trimethoprim, tylosin, and lincomycin) to algal and cyanobacterial species in European surface waters. Ecotoxicity tests were initially performed to assess the combined effects of the antibiotics to the cyanobacteria Anabaena flos-aquae. The results were used to evaluate two mixture prediction models: concentration addition (CA) and independent action (IA). The CA model performed best at predicting the toxicity of the mixture with the experimental 96 h EC50 for the antibiotic mixture being 0.248 μmol/L compared to the CA predicted EC50 of 0.21 μmol/L. The CA model was therefore used alongside predictions of exposure for different European scenarios and estimations of hazards obtained from species sensitivity distributions to estimate risks of mixtures of the three antibiotics. Risk quotients for the different scenarios ranged from 0.066 to 385 indicating that the combination of three substances could be causing adverse impacts on algal communities in European surface waters. This could have important implications for primary production and nutrient cycling. Tylosin contributed most to the risk followed by lincomycin and trimethoprim. While we have explored only three antibiotics, the combined experimental and modeling approach could readily be applied to the wider range of antibiotics that are in use
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