576 research outputs found
Exactly solvable Ising--Heisenberg chain with triangular XXZ-Heisenberg plaquettes
A mixed Ising-Heisenberg spin system consisting of triangular XXZ-Heisenberg
spin clusters assembled into a chain by alternating with Ising spins
interacting to all three spins in the triangle is considered. The exact
solution of the model is given in terms of the generalized
decoration--iteration map and within the transfer-matrix technique. Exact
expressions for thermodynamic functions are derived. Ground state phase
diagrams, thermodynamic and magnetic properties of the system are examined.Comment: 16 pages, 12 figure
Improved Orbital Parameters and Transit Monitoring for HD 156846b
HD 156846b is a Jovian planet in a highly eccentric orbit (e = 0.85) with a
period of 359.55 days. The pericenter passage at a distance of 0.16 AU is
nearly aligned to our line of sight, offering an enhanced transit probability
of 5.4% and a potentially rich probe of the dynamics of a cool planetary
atmosphere impulsively heated during close approach to a bright star (V = 6.5).
We present new radial velocity (RV) and photometric measurements of this star
as part of the Transit Ephemeris Refinement and Monitoring Survey (TERMS). The
RV measurements from Keck-HIRES reduce the predicted transit time uncertainty
to 20 minutes, an order of magnitude improvement over the ephemeris from the
discovery paper. We photometrically monitored a predicted transit window under
relatively poor photometric conditions, from which our non-detection does not
rule out a transiting geometry. We also present photometry that demonstrates
stability at the millimag level over its rotational timescale.Comment: 7 pages, 4 figures, accepted for publication in Ap
Nasalization by Nasalis larvatus: larger noses audiovisually advertise conspecifics in proboscis monkeys
Male proboscis monkeys have uniquely enlarged noses that are prominent adornments, which may have evolved through their sexually competitive harem group social system. Nevertheless, the ecological roles of the signals encoded by enlarged noses remain unclear. We found significant correlations among nose, body, and testis sizes and a clear link between nose size and number of harem females. Therefore, there is evidence supporting both male-male competition and female choice as causal factors in the evolution of enlarged male noses. We also observed that nasal enlargement systematically modifies the resonance properties of male vocalizations, which probably encode male quality. Our results indicate that the audiovisual contributions of enlarged male noses serve as advertisements to females in their mate selection. This is the first primate research to evaluate the evolutionary processes involved in linking morphology, acoustics, and socioecology with unique masculine characteristics
Administrators in higher education: organizational expansion in a transforming institution
Recent European research has revealed growth in the number of administrators and professionals across different sections of universities—a long established trend in US universities. We build on this research by investigating the factors associated with variation in the proportion of administrators across 761 Higher Education Institutions (HEIs) in 11 European countries. We argue that the enactment of expanded and diversified missions of HE is one of the main factors nurturing universities’ profesional and administrative bodies. Our findings support such an assertion; regardless of geographical and institutional differences, HEIs with high levels of “entrepreneurialism” (e.g. in service provision and external engagement) are characterized by a larger proportion of administrative staff. However, we find no empirical support for arguments citing structural pressures and demands on HEIs due to higher student enrolments, budget cuts or deregulation as engines driving such change. Instead, our results point towards, as argued by neo-institutionalists, the diffusion of formal organization as a model of institutional identity and purpose, which is especially prevalent at high levels of external connectedness
Chagas Disease in the New York City Metropolitan Area
Background
Chagas disease, caused by the parasite Trypanosoma cruzi, once considered a disease confined to Mexico, Central America, and South America, is now an emerging global public health problem. An estimated 300 000 immigrants in the United States are chronically infected with T. cruzi. However, awareness of Chagas disease among the medical community in the United States is poor.
Methods
We review our experience managing 60 patients with Chagas disease in hospitals throughout the New York City metropolitan area and describe screening, clinical manifestations, EKG findings, imaging, and treatment.
Results
The most common country of origin of our patients was El Salvador (n = 24, 40%), and the most common detection method was by routine blood donor screening (n = 21, 35%). Nearly half of the patients were asymptomatic (n = 29, 48%). Twenty-seven patients were treated with either benznidazole or nifurtimox, of whom 7 did not complete therapy due to side effects or were lost to follow-up. Ten patients had advanced heart failure requiring device implantation or organ transplantation.
Conclusions
Based on our experience, we recommend that targeted screening be used to identify at-risk, asymptomatic patients before progression to clinical disease. Evaluation should include an electrocardiogram, echocardiogram, and chest x-ray, as well as gastrointestinal imaging if relevant symptoms are present. Patients should be treated if appropriate, but providers should be aware of adverse effects that may prevent patients from completing treatment
Role and promise of health policy and systems research in integrating rehabilitation into the health systems
Despite recognized need and reasonable demand, health systems and rehabilitation communities keep working in silos, independently with minimal recognition to the issues of those who require rehabilitation services. Consolidated effort by health systems and rehabilitation parties, recognizing the value, power and promise of each other, is a need of the hour to address this growing issue of public health importance. In this paper, the importance and the need for integration of rehabilitation into health system is emphasized. The efforts being made to integrate rehabilitation into health systems and the potential challenges in integration of these efforts were discussed. Finally, the strategies and benefits of integrating rehabilitation in health systems worldwide is proposed. Health policy and systems research (HPSR) brings a number of assets that may assist in addressing the obstacles discussed above to universal coverage of rehabilitation. It seeks to understand and improve how societies organize themselves to achieve collective health goals; considers links between health systems and social determinants of health; and how different actors interact in policy and implementation processes. This multidisciplinary lens is essential for evidence and learning that might overcome the obstacles to the provision of rehabilitation services, including integration into health systems. Health systems around the world can no longer afford to ignore rehabilitation needs of their populations and the World Health Assembly (WHA) resolution marked a global call to this effect. Therefore, national governments and global health community must invest in setting a priority research agenda and promote the integration of rehabilitation into health systems. The context-specific, need-based and policy-relevant knowledge about this must be made available globally, especially in low- and middle-income countries. This could help integrate and implement rehabilitation in health systems of countries worldwide and also help achieve the targets of Rehabilitation 2030, universal health coverage and Sustainable Development Goals
Universities’ pursuit of inclusion and its effects on professional staff: the case of the United Kingdom
This paper explores the proliferation of non-academic professionals as a cultural response to universities’ mission of inclusion. Departing from a neo-institutionalist perspective, the author argues that the diffusion of highly rationalised models of institutional action shapes universities as formal organisations who engage with new levels of professional expertise in the pursuit of goals and missions. The United Kingdom (UK) offers an illustrative example, the emergence of statutory equality duties on public institutions (race equality duty 2001, disability equality duty 2006 and gender equality duty 2007) nurturing an image of universities as strategic for the pursuit of demographic inclusion. Using yearly longitudinal data on 109 UK universities from 2003 to 2011, the author shows that universities increase their professional staff in catering for demographic inclusion in terms of ethnicity and disability, revealing highly rationalised institutional responses to the aforementioned equality duties. The findings contribute to the neo-institutionalist literature drawing attention to the transformation of universities into organisational actors (i.e. highly integrated entities, strategically oriented towards the pursuit of formally articulated goals and targets), which contrasts with traditional conceptions of the university as an institution with a taken-for-granted societal role and loosely defined organisational backbone. The findings provide the impetuous for further empirical research into the role of professional staff as universities assimilate new goals and missions
Chikungunya virus infections among travellers returning to Spain, 2008 to 2014
Since the first documented autochthonous transmission of
chikungunya virus in the Caribbean island of Saint Martin in
2013, the infection has been reported within the Caribbean
region as well as North, Central and South America. The risk of
autochthonous transmission of chikungunya virus becoming
established in Spain may be elevated due to the large numbers of
travellers returning to Spain from countries affected by the
2013 epidemic in the Caribbean and South America, as well as the
existence of the Aedes albopictus vector in certain parts of
Spain. We retrospectively analysed the laboratory diagnostic
database of the National Centre for Microbiology, Institute of
Health Carlos III (CNM-ISCIII) from 2008 to 2014. During the
study period, 264 confirmed cases, of 1,371 suspected cases,
were diagnosed at the CNM-ISCIII. In 2014 alone, there were 234
confirmed cases. The highest number of confirmed cases were
reported from the Dominican Republic (n = 136), Venezuela (n =
30) and Haiti (n = 11). Six cases were viraemic in areas of
Spain where the vector is present. This report highlights the
need for integrated active case and vector surveillance in Spain
and other parts of Europe where chikungunya virus may be
introduced by returning travellers
Viral genome wide association study identifies novel hepatitis C virus polymorphisms associated with sofosbuvir treatment failure
Persistent hepatitis C virus (HCV) infection is a major cause of chronic liver disease, worldwide. With the development of direct-acting antivirals, treatment of chronically infected patients has become highly effective, although a subset of patients responds less well to therapy. Sofosbuvir is a common component of current de novo or salvage combination therapies, that targets the HCV NS5B polymerase. We use pre-treatment whole-genome sequences of HCV from 507 patients infected with HCV subtype 3a and treated with sofosbuvir containing regimens to detect viral polymorphisms associated with response to treatment. We find three common polymorphisms in non-targeted HCV NS2 and NS3 proteins are associated with reduced treatment response. These polymorphisms are enriched in post-treatment HCV sequences of patients unresponsive to treatment. They are also associated with lower reductions in viral load in the first week of therapy. Using in vitro short-term dose-response assays, these polymorphisms do not cause any reduction in sofosbuvir potency, suggesting an indirect mechanism of action in decreasing sofosbuvir efficacy. The identification of polymorphisms in NS2 and NS3 proteins associated with poor treatment outcomes emphasises the value of systematic genome-wide analyses of viruses in uncovering clinically relevant polymorphisms that impact treatment
Towards an integrative understanding of soil biodiversity
Soil is one of the most biodiverse terrestrial habitats. Yet, we lack an integrative conceptual framework for understanding the patterns and mechanisms driving soil biodiversity. One of the underlying reasons for our poor understanding of soil biodiversity patterns relates to whether key biodiversity theories (historically developed for aboveground and aquatic organisms) are applicable to patterns of soil biodiversity. Here, we present a systematic literature review to investigate whether and how key biodiversity theories (species-energy relationship, theory of island biogeography, metacommunity theory, niche theory and neutral theory) can explain observed patterns of soil biodiversity. We then discuss two spatial compartments nested within soil at which biodiversity theories can be applied to acknowledge the scale-dependent nature of soil biodiversity.Peer reviewe
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