59 research outputs found
A lower bound for the BCS functional with boundary conditions at infinity
We consider a many-body system of fermionic atoms interacting via a local
pair potential and subject to an external potential within the framework of BCS
theory. We measure the free energy of the whole sample with respect to the free
energy of a reference state which allows us to define a BCS functional with
boundary conditions at infinity. Our main result is a lower bound for this
energy functional in terms of expressions that typically appear in
Ginzburg-Landau functionals.Comment: 32 page
Behind film performance in China’s changing institutional context:The impact of signals
Grounded in signaling theory, this paper investigates the signals reflecting product quality, innovativeness, reputation and cultural background which influence film performance, i.e. film survival (duration on cinema screen) and box office success, in China’s changing institutional context. This market has grown substantially and still possesses potential for further development. However, China’s unique institutional context presents challenges. By examining an expanded range of potential signals, two of which have not previously been examined in the literature, namely imported films and enhanced format film formats such as 3D and IMAX, we develop a conceptual framework and argue that signaling theory needs to be combined with institutional context. Similar to findings for film industries in other countries, we find quality and reputational signals including budget, star power, sequels, and online consumer reviews to be important in China. However, unique results are also revealed. Chinese consumers react to an innovativeness signal in that they are specifically attracted to enhanced format films. Film award nominations and prizes are insignificant reputational signals. Once other signals are taken into account, imported films on average do not perform as well as domestic films. We link these findings to China’s unique institutional setting and offer important implications for management, recognizing the challenges to film companies of competing in an increasingly globalized market. The paper is also of relevance to policymakers given their continued efforts in shaping the development of China’s film industry
What is the right profile for getting a job? A stated choice experiment of the recruitment process
Plant-made vaccines in support of the Millennium Development Goals
Vaccines are one of the most successful public health achievements of the last century. Systematic immunisation programs have reduced the burden of infectious diseases on a global scale. However, there are limitations to the current technology, which often requires costly infrastructure and long lead times for production. Furthermore, the requirement to keep vaccines within the cold-chain throughout manufacture, transport and storage is often impractical and prohibitively expensive in developing countries—the very regions where vaccines are most needed. In contrast, plant-made vaccines (PMVs) can be produced at a lower cost using basic greenhouse agricultural methods, and do not need to be kept within such narrow temperature ranges. This increases the feasibility of developing countries producing vaccines locally at a small-scale to target the specific needs of the region. Additionally, the ability of plant-production technologies to rapidly produce large quantities of strain-specific vaccine demonstrates their potential use in combating pandemics. PMVs are a proven technology that has the potential to play an important role in increasing global health, both in the context of the 2015 Millennium Development Goals and beyond
Effect of variable transmission rate on the dynamics of HIV in sub-Saharan Africa
<p>Abstract</p> <p>Background</p> <p>The cause of the high HIV prevalence in sub-Saharan Africa is incompletely understood, with heterosexual penile-vaginal transmission proposed as the main mechanism. Heterosexual HIV transmission has been estimated to have a very low probability; but effects of cofactors that vary in space and time may substantially alter this pattern.</p> <p>Methods</p> <p>To test the effect of individual variation in the HIV infectiousness generated by co-infection, we developed and analyzed a mathematical sexual network model that simulates the behavioral components of a population from Malawi, as well as the dynamics of HIV and the co-infection effect caused by other infectious diseases, including herpes simplex virus type-2, gonorrhea, syphilis and malaria.</p> <p>Results</p> <p>The analysis shows that without the amplification effect caused by co-infection, no epidemic is generated, and HIV prevalence decreases to extinction. But the model indicates that an epidemic can be generated by the amplification effect on HIV transmission caused by co-infection.</p> <p>Conclusion</p> <p>The simulated sexual network demonstrated that a single value for HIV infectivity fails to describe the dynamics of the epidemic. Regardless of the low probability of heterosexual transmission per sexual contact, the inclusion of individual variation generated by transient but repeated increases in HIV viral load associated with co-infections may provide a biological basis for the accelerated spread of HIV in sub-Saharan Africa. Moreover, our work raises the possibility that the natural history of HIV in sub-Saharan Africa cannot be fully understood if individual variation in infectiousness is neglected.</p
Measuring women's perceived ability to overcome barriers to healthcare seeking in Burkina Faso
Differences between seven measures of self-reported numbers of clients of female sex workers in southern India: implications for individual- and population-level analysis.
Quantifying sexual activity of sub-populations with high-risk sexual behaviour is important in understanding HIV epidemiology. This study examined inconsistency of seven outcomes measuring self-reported clients per month (CPM) of female sex workers (FSWs) in southern India and implications for individual/population-level analysis. Multivariate negative binomial regression was used to compare key social/environmental factors associated with each outcome. A transmission dynamics model was used to assess the impact of differences between outcomes on population-level FSW/client HIV prevalence. Outcomes based on 'clients per last working day' produced lower estimates than those based on 'clients per typical day'. Although the outcomes were strongly correlated, their averages differed by approximately two-fold (range 39.0-79.1 CPM). The CPM measure chosen did not greatly influence standard epidemiological 'risk factor' analysis. Differences across outcomes influenced HIV prevalence predictions. Due to this uncertainty, we recommend basing population-based estimates on the range of outcomes, particularly when assessing the impact of interventions
Application of discrete choice experiments to enhance stakeholder engagement as a strategy for advancing implementation: a systematic review
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