483 research outputs found
Collision rate constants for polarizable ions
AbstractLangevin described a model for the interaction between an ion and a neutral nearly a century ago and since then, many modifications have been introduced to adjust for specific circumstances. This work discusses the induced dipole–induced dipole interaction between an ion and a neutral without a permanent dipole and introduces an anisotropic adjustment. A point polarizable ion model (PPI) and an orientation dependent polarizable ion model (ODPI) are discussed and applied to systems where the ion is highly polarizable and the neutral is only weakly polarizable. Significant deviations from classical Langevin rate constants and significant differences between PPI and ODPI are observed
Donor characteristics and the allocation of aid to climate mitigation finance
We make use of a panel dataset of 22 donor countries from 1998 to 2009 to examine the links between donor characteristics and the share of overseas development assistance allocated to climate mitigation finance. We find that donors with a larger green domestic budget tend to allocate a smaller portion of overseas aid to mitigation finance (possibly as a result of a competing interest between spending on domestic environmental projects and international climate projects). The opposite holds for donor countries with better institutions (governance) that have ratified the Kyoto Protocol. We also find important discrepancies when comparing the effects of donor characteristics on committed versus disbursed mitigation finance (as a share of aid). For the latter, only commitment to the Kyoto Protocol appears to be of high statistical significance
The role played by cell-substrate interactions in the pathogenesis of osteoclast-mediated peri-implant osteolysis
Prosthetic wear debris-induced peri-implant osteolysis is a major cause of aseptic loosening after total joint replacement. In this condition, wear particles released from the implant components induce a granulomatous inflammatory reaction at the interface between implant and adjacent bone, leading to progressive bone resorption and loss of fixation. The present study was undertaken to characterize definitively the phenotype of osteoclast-like cells associated with regions of peri-implant focal bone resorption and to compare the phenotypic features of these cells with those of mononucleated and multinucleated cells associated with polyethylene wear particles. Peri-implant tissues were obtained from patients undergoing hip revision surgery for aseptic loosening after total joint replacement. Cells were examined for the expression of several markers associated with the osteoclast phenotype using immunohistochemistry, histochemistry, and/or in situ hybridization. CD68 protein, a marker expressed by multiple macrophage lineage cell types, was detected in mononucleated and multinucleated cells associated with polyethylene particles and the bone surface. Cathepsin K and tartrate-resistant acid phosphatase were expressed highly in both mononucleated and multinucleated cells associated with the bone surface. Levels of expression were much lower in cells associated with polyethylene particles. High levels of β(3 )integrin protein were detected in cells in contact with bone. Multinucleated cells associated with polyethylene particles exhibited faint positive staining. Calcitonin receptor mRNA expression was detected solely in multinucleated cells present in resorption lacunae on the bone surface and was absent in cells associated with polyethylene particles. Our findings provide further evidence that cells expressing the full repertoire of osteoclast phenotypic markers are involved in the pathogenesis of peri-implant osteolysis after total joint replacement. They also demonstrate that foreign body giant cells, although believed to be phenotypically and functionally distinct from osteoclasts, express many osteoclast-associated genes and gene products. However, the levels and patterns of expression of these genes in the two cell types differ. We speculate that, in addition to the role of cytokines and growth factors, the substrate with which these cells interact plays a critical role in their differential phenotypic and functional properties
Pattern and determinants of HIV research productivity in sub-Saharan Africa: bibliometric analysis of 1981 to 2009 PubMed papers
<p>Abstract</p> <p>Background</p> <p>Several bibliometric studies have been published on AIDS. The findings obtained from these studies have provided a general picture of the history and growth of AIDS literature. However, factors related to variation in HIV research productivity in sub-Saharan Africa have not been examined. Therefore, this study aims to fill some of the gap in existing research to provide insights into factors associated with HIV research productivity in sub-Saharan Africa.</p> <p>Methods</p> <p>A bibliometric analysis regarding sub-Saharan Africa HIV/AIDS research was conducted in the PubMed database for the period of 1981 to 2009. The numbers of HIV research articles indexed in PubMed was used as surrogate for total HIV research productivity. Series of univariable and multivariable negative binomial regression models were used to explore factors associated with variation in HIV research productivity in sub-Saharan Africa.</p> <p>Results</p> <p>First authors from South Africa, Uganda and Kenya contributed almost half of the total number of HIV articles indexed in PubMed between 1981 and 2009. Uganda, Zimbabwe and Malawi had better records when the total production was adjusted for gross domestic product (GDP). Comoros, the Gambia and Guinea-Bissau were the most productive countries when the total products were normalized by number of people with HIV. There were strong positive and statistically significant correlation between countries number of indexed journal (Pearson correlation r = 0.77, p = .001), number of higher institutions (r = 0.60, p = .001), number of physicians (r = 0.83, p = .001) and absolute numbers of HIV articles.</p> <p>Conclusions</p> <p>HIV research productivity in Africa is highly skewed. To increase HIV research output, total expenditure on health (% of GDP), private expenditure on health, and adult literacy rate may be important factors to address.</p
Antibiotic-resistant bacteria, antibiotic resistance genes, and antibiotic residues in wastewater from a poultry slaughterhouse after conventional and advanced treatments
Slaughterhouse wastewater is considered a reservoir for antibiotic-resistant bacteria and antibiotic residues, which are not sufficiently removed by conventional treatment processes. This study focuses on the occurrence of ESKAPE bacteria (Enterococcus spp., S. aureus, K. pneumoniae, A. baumannii, P. aeruginosa, Enterobacter spp.), ESBL (extended-spectrum β-lactamase)-producing E. coli, antibiotic resistance genes (ARGs) and antibiotic residues in wastewater from a poultry slaughterhouse. The efficacy of conventional and advanced treatments (i.e., ozonation) of the in-house wastewater treatment plant regarding their removal was also evaluated. Target culturable bacteria were detected only in the influent and effluent after conventional treatment. High abundances of genes (e.g., bla, bla, bla, bla, bla and mcr-1) of up to 1.48 × 10 copies/100 mL were detected in raw influent. All of them were already significantly reduced by 1–4.2 log units after conventional treatment. Following ozonation, mcr-1 and bla were further reduced below the limit of detection. Antibiotic residues were detected in 55.6% (n = 10/18) of the wastewater samples. Despite the significant reduction through conventional and advanced treatments, effluents still exhibited high concentrations of some ARGs (e.g., sul1, ermB and bla), ranging from 1.75 × 10 to 3.44 × 10 copies/100 mL. Thus, a combination of oxidative, adsorptive and membrane-based technologies should be considered
Theory of Magneto--Acoustic Transport in Modulated Quantum Hall Systems Near
Motivated by the experimental results of Willett et al [Phys.Rev. Lett., {\bf
78}, 4478 (1997)] we develop a magneto-transport theory for the response of a
two dimensional electron gas (2DEG) in the Fractional Quantum Hall Regime near
Landau level filling factor to the surface acoustic wave (SAW) in
the presence of an added periodic density modulation. We assume there exists a
Composite Fermion Fermi Surface (CF-FS) at , and we show that the
deformation of the (CF-FS) due to the density modulation can be at the origin
of the observed transport anomalies for the experimental conditions. Our
analysis is carried out particularly for the non-local case which corresponds
to the SAW experiments. We introduce a new model of a deformed CF-FS. The model
permits us to explain anomalous features of the response of the modulated 2DEG
to the SAW near namely the nonlinear wave vector dependence of the
electron conductivity, the appearance of peaks in the SAW velocity shift and
attenuation and the anisotropy of the effect, all of which originate from
contributions to the conductivity tensor due to the regions of the CF-FS which
are flattened by the applied modulation.Comment: 13 pages, 4 figures, the published versio
What is multidisciplinary cancer care like in practice? a protocol for a mixed-method study to characterise ambulatory oncology services in the Australian public sector
© 2019 Author(s). Introduction An understanding of the real-world provision of oncology outpatient services can help maintain service quality in the face of escalating demand and tight budgets, by informing the design of interventions that improve the effectiveness or efficiency of provision. The aims of this study are threefold. First, to develop an understanding of cancer services in outpatient clinics by characterising the organisation and practice of multidisciplinary care (MDC). Second, to explore the key areas of: (a) clinical decision-making and (b) engagement with patients' supportive needs. Third, to identify barriers to, and facilitators of, the delivery of quality care in these settings. Methods and analysis A suite of mixed-methods studies will be implemented at six hospitals providing cancer outpatient clinics, with a staged roll-out. In Stage One, we will examine policies, use unstructured observations and undertake interviews with key health professionals to characterise the organisation and delivery of MDC. In Stage Two, observations of practice will continue, to deepen our understanding, and to inform two focused studies. The first will explore decision-making practices and the second will examine how staff engage with patients' needs; both studies involve interviews, to complement observation. As part of the study of supportive care, we will examine the implications of an introduction of patient-reported measures (PRMs) into care, adding surveys to interviews before and after PRMs roll-out. Data analysis will account for site-specific and cross-site issues using an adapted Qualitative Rapid Appraisal, Rigorous Analysis approach. Quantitative data from clinician surveys will be statistically analysed and triangulated with the related qualitative study findings. Ethics and dissemination Ethical approval was granted by South Eastern Sydney Local Health District Human Research Ethics Committee (no. 18/207). Findings will be shared with participating hospitals and widely disseminated through publications and presentations
Millennium Development Goals: Tool or token of global social governance?
In this paper we argue that the Millennium Development Goals (MDGs) experience suggests that Global Social Governance (GSG) exists and that the MDGs have been an effective tool in creating a global accountability framework despite shortcomings mainly arising in the formulation process. The paper first discusses the historical emergence of the MDGs, leading to questions of ownership and responsibilities of developing and developed countries respectively. Subsequently, we assess whether the MDGs comprehensively reflect development concepts and address the question whether the MDGs had an impact on national policies, and ultimately on people's lives. Eventually, these questions and their answers are intended to stimulate and inform discussions on the post-2015 development agenda as a - potentially improved - GSG tool. Keywords: Millennium Development Goals, Global Social Governance, post-2015 development agend
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