Trends in Compulsory Licensing of Pharmaceuticals Since the Doha Declaration: A Database Analysis

Reed Beall and Randall Kuhn describe their findings from an analysis of use of compulsory licenses for pharmaceutical products by World Trade Organization members since 1995

Mass-to-Light Ratios of Groups and Clusters of Galaxies

We constrain the mass-to-light ratios, gas mass fractions, baryon mass fractions and the ratios of total to luminous mass for a sample of eight nearby relaxed galaxy groups and clusters: A262, A426, A478, A1795, A2052, A2063, A2199 and MKW4s. We use ASCA spatially resolved spectroscopic X-ray observations and ROSAT PSPC images to constrain the total and gas masses of these clusters. To measure cluster luminosities we use galaxy catalogs resulting from the digitization and automated processing of the second generation Palomar Sky Survey plates calibrated with CCD images in the Gunn-Thuan g, r, and i bands. Under the assumption of hydrostatic equilibrium and spherical symmetry, we can measure the total masses of clusters from their intra-cluster gas temperature and density profiles. Spatially resolved ASCA spectra show that the gas temperature decreases with increasing distance from the center. By comparison, the assumption that the gas is isothermal results in an underestimate of the total mass at small radii, and an overestimate at large cluster radii. We have obtained luminosity functions for all clusters in our sample. After correcting for background and foreground galaxies, we estimate the total cluster luminosity using Schechter function fits to the galaxy catalogs. In the three lowest redshift clusters where we can sample to fainter absolute magnitudes, we have detected a flattening of the luminosity function at intermediate magnitudes and a rise at the faint end. These clusters were fit with a sum of two Schechter functions. The remaining clusters were well fit with a single Schechter function.Comment: 11 pages 5 figures, accepted for publication in the Ap

True versus False Parasite Interactions: A Robust Method to Take Risk Factors into Account and Its Application to Feline Viruses

International audienceBACKGROUND: Multiple infections are common in natural host populations and interspecific parasite interactions are therefore likely within a host individual. As they may seriously impact the circulation of certain parasites and the emergence and management of infectious diseases, their study is essential. In the field, detecting parasite interactions is rendered difficult by the fact that a large number of co-infected individuals may also be observed when two parasites share common risk factors. To correct for these "false interactions", methods accounting for parasite risk factors must be used. METHODOLOGY/PRINCIPAL FINDINGS: In the present paper we propose such a method for presence-absence data (i.e., serology). Our method enables the calculation of the expected frequencies of single and double infected individuals under the independence hypothesis, before comparing them to the observed ones using the chi-square statistic. The method is termed "the corrected chi-square." Its robustness was compared to a pre-existing method based on logistic regression and the corrected chi-square proved to be much more robust for small sample sizes. Since the logistic regression approach is easier to implement, we propose as a rule of thumb to use the latter when the ratio between the sample size and the number of parameters is above ten. Applied to serological data for four viruses infecting cats, the approach revealed pairwise interactions between the Feline Herpesvirus, Parvovirus and Calicivirus, whereas the infection by FIV, the feline equivalent of HIV, did not modify the risk of infection by any of these viruses. CONCLUSIONS/SIGNIFICANCE: This work therefore points out possible interactions that can be further investigated in experimental conditions and, by providing a user-friendly R program and a tutorial example, offers new opportunities for animal and human epidemiologists to detect interactions of interest in the field, a crucial step in the challenge of multiple infections

Evidence-based PET for thoracic tumours

AbstractFluorine-18 fluorodeoxyglucose positron emission tomography/computed tomography (18F-FDG PET/CT) is a robust imaging tool that is currently used in daily clinical practice for the evaluation of thoracic malignancies. This chapter provides an overview of the current evidence-based data on the usefulness of PET/CT for the evaluation of patients with thoracic tumours including lung cancer, pleural and thymic tumours, and esophageal cancer

A method for analysing web systems model alignment

The introduction or modification of IT systems will often lead to the need for consequential changes to the associated business processes. This is particularly true for Web systems, where the system can be much more deeply intertwined with the business processes. The failure to identify these potential impacts early on can lead to major delays or cost increases in the development process, and subsequent redevelopment as the IT system and business processes are appropriately modified to bring them into alignment. We believe that early modelling of the existing business processes, and their relationship to the IT systems, as well as the potential changes to these processes will allow the identification of misalignments in the model which are a reflection of likely misalignments which would exist in the actual processes if the changes were to be implemented. This then will allow rectification of the misalignment much earlier than is currently the case. It is worth noting that his does not necessarily require new modelling notations, but rather the use of existing notations in new ways combined with appropriate analysis tools. This research aims to demonstrate that this identification of misalignments can be achieved using existing modelling notations by applying algorithmic analysis to the information about the business process captured in the model. This can be achieved by integrating this analysis with modelling tools, and hence supporting the identification of likely flaws in a proposed changed business process before that process is actually implemented. This paper presents a proof of concept that demonstrates an approach to analysing the properties of model elements using a constraint-based rule system in conjunction with an existing widely-used modelling tool. © 2008. Andrew Bucknell, David Lowe, Didar Zowghi