225 research outputs found
Social Identity in Deaf Culture: A Comparison of Ideologies
The emergence of Deaf culture and recent developments in identity research fueled by cultural diversity has ignited exploration of identity development in deaf people. The issue of how individuals go through the process of developing identities related to being deaf is now receiving much attention. Two major theoretical models in the literature, specifically racial identity development models and bicultural/acculturation models are presented and then discussed in terms of how they might apply to deaf people. Subsequently, we describe two separate measures that have been developed to empirically test the application of these models to deaf populations. While research on both measures indicates good psychometric properties, ongoing reconceptualization of social identity models that may explain how deaf people develop identities related to Deaf and hearing societies continues to be necessary. It is hoped that these measures will lead to better understanding of the relationship between aspects of identity and healthy psychological adjustment in deaf people
Wolves: Behavior, Ecology, and Conservation: Photo Section II
Adult wolves are very attentive to the pups. Both parents feed and care for them. Any older siblings similarly participate in pup care and feeding. Kin selection is probably the best explanation for the latter behavior. Top: Photograph by Isaac Babcock. Bottom: Photograph by L. David Mech
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On-Road Development of John Deere 6081 Natural Gas Engine: Final Technical Report, July 1999 - January 2001
Report that discusses John Deere's field development of a heavy-duty natural gas engine. As part of the field development project, Waste Management of Orange County, California refitted four existing trash packers with John Deere's prototype spark ignited 280-hp 8.1 L CNG engines. This report describes the project and also contains information about engine performance, emissions, and driveability
Impact of Emerging Antiviral Drug Resistance on Influenza Containment and Spread: Influence of Subclinical Infection and Strategic Use of a Stockpile Containing One or Two Drugs
BACKGROUND: Wide-scale use of antiviral agents in the event of an influenza pandemic is likely to promote the emergence of drug resistance, with potentially deleterious effects for outbreak control. We explored factors promoting resistance within a dynamic infection model, and considered ways in which one or two drugs might be distributed to delay the spread of resistant strains or mitigate their impact. METHODS AND FINDINGS: We have previously developed a novel deterministic model of influenza transmission that simulates treatment and targeted contact prophylaxis, using a limited stockpile of antiviral agents. This model was extended to incorporate subclinical infections, and the emergence of resistant virus strains under the selective pressure imposed by various uses of one or two antiviral agents. For a fixed clinical attack rate, R(0) rises with the proportion of subclinical infections thus reducing the number of infections amenable to treatment or prophylaxis. In consequence, outbreak control is more difficult, but emergence of drug resistance is relatively uncommon. Where an epidemic may be constrained by use of a single antiviral agent, strategies that combine treatment and prophylaxis are most effective at controlling transmission, at the cost of facilitating the spread of resistant viruses. If two drugs are available, using one drug for treatment and the other for prophylaxis is more effective at preventing propagation of mutant strains than either random allocation or drug cycling strategies. Our model is relatively straightforward, and of necessity makes a number of simplifying assumptions. Our results are, however, consistent with the wider body of work in this area and are able to place related research in context while extending the analysis of resistance emergence and optimal drug use within the constraints of a finite drug stockpile. CONCLUSIONS: Combined treatment and prophylaxis represents optimal use of antiviral agents to control transmission, at the cost of drug resistance. Where two drugs are available, allocating different drugs to cases and contacts is likely to be most effective at constraining resistance emergence in a pandemic scenario
Classifying maternal deaths in Suriname using WHO ICD-MM: different interpretation by Physicians, National and International Maternal Death Review Committees
Plain English summary: The World Health Organization (WHO) provides a framework (ICD-MM) to classify pregnancy-related deaths systematically, which enables global comparison among countries. We compared the classification of pregnancy-related deaths in Suriname by the attending physician and by the national maternal death review (MDR) committee and among the MDR committees of Suriname, Jamaica and the Netherlands. There were 89 possible pregnancy-related deaths in Suriname between 2010 and 2014. Nearly half (47%) were classified differently by the Surinamese MDR committee as compared to the classification of the attending physicians. All three MDR committees agreed that 18% (n = 16/89) of the cases were no maternal deaths. Out of the remaining 73 cases, there was disagreement regarding whether 15% (n = 11) were maternal deaths. The Surinamese and Jamaican MDR committees achieved greater consensus in classification than the Surinamese and the Netherlands MDR committees. The Netherlands MDR committee classified more deaths as unspecified than Surinamese and the Jamaican MDR committees. Underlying causes that achieved a high level of agreement among the three committees were abortive outcomes and obstetric hemorrhage, while little agreement was reported for unspecified and other direct causes. The issues encountered during maternal death classification using the ICD-MM guidelines included classification of suicide during early pregnancy; when to assume pregnancy without objective evidence; how to count maternal deaths occurring outside the country of residence; the relevance of direct or indirect cause attribution; and how to select the underlying cause when direct and indirect conditions or multiple comorbidities co-occur. Addressing these classification barriers in future revisions of the ICD-MM guidelines could enhance the feasibility of maternal death classification and facilitate global comparison. Background: Insight into the underlying causes of pregnancy-related deaths is essential to develop policies to avert preventable deaths. The WHO International Classification of Diseases-Maternal Mortality (ICD-MM) guidelines provide a framework to standardize maternal death classifications and enable comparison in and among countries over time. However, despite the implementation of these guidelines, differences in classification remain. We evaluated consensus on maternal death classification using the ICD-MM guidelines. Methods: The classification of pregnancy-related deaths in Suriname during 2010–2014 was compared in the country (between the attending physician and the national maternal death review (MDR) committee), and among the MDR committees from Suriname, Jamaica and the Netherlands. All reviewers applied the ICD-MM guidelines. The inter-rater reliability (Fleiss kappa [κ]) was used to measure agreement. Results: Out of the 89 cases certified by attending physicians, 47% (n = 42) were classified differently by the Surinamese MDR committee. The three MDR committees agreed that 18% (n = 16/89) of these cases were no maternal deaths, and, therefore, excluded from further analyses. However, opinions differed whether 15% (n = 11) of the remaining 73 cases were maternal deaths. The MDR committees achieved moderate agreement classifying the deaths into type (direct, indirect and unspecified) (κ = 0.53) and underlying cause group (κ = 0.52). The Netherlands MDR committee classified more maternal deaths as unspecified (19%), than the Jamaican (7%) and Surinamese (4%) committees did. The mutual agreement between the Surinamese and Jamaican MDR committees (κ = 0.69 vs κ = 0.63) was better than between the Surinamese and the Netherlands MDR committees (κ = 0.48 vs κ = 0.49) for classification into type and underlying cause group, respectively. Agreement on the underlying cause category was excellent for abortive outcomes (κ = 0.85) and obstetric hemorrhage (κ = 0.74) and fair for unspecified (κ = 0.29) and other direct causes (κ = 0.32). Conclusions: Maternal death classification differs in Suriname and among MDR committees from different countries, despite using the ICD-MM guidelines on similar cases. Specific challenges in applying these guidelines included attribution of underlying cause when comorbidities occurred, the inclusion of deaths from suicides, and maternal deaths that occurred outside the country of residence
Extracellular Matrix Aggregates from Differentiating Embryoid Bodies as a Scaffold to Support ESC Proliferation and Differentiation
Embryonic stem cells (ESCs) have emerged as potential cell sources for tissue engineering and regeneration owing to its virtually unlimited replicative capacity and the potential to differentiate into a variety of cell types. Current differentiation strategies primarily involve various growth factor/inducer/repressor concoctions with less emphasis on the substrate. Developing biomaterials to promote stem cell proliferation and differentiation could aid in the realization of this goal. Extracellular matrix (ECM) components are important physiological regulators, and can provide cues to direct ESC expansion and differentiation. ECM undergoes constant remodeling with surrounding cells to accommodate specific developmental event. In this study, using ESC derived aggregates called embryoid bodies (EB) as a model, we characterized the biological nature of ECM in EB after exposure to different treatments: spontaneously differentiated and retinoic acid treated (denoted as SPT and RA, respectively). Next, we extracted this treatment-specific ECM by detergent decellularization methods (Triton X-100, DOC and SDS are compared). The resulting EB ECM scaffolds were seeded with undifferentiated ESCs using a novel cell seeding strategy, and the behavior of ESCs was studied. Our results showed that the optimized protocol efficiently removes cells while retaining crucial ECM and biochemical components. Decellularized ECM from SPT EB gave rise to a more favorable microenvironment for promoting ESC attachment, proliferation, and early differentiation, compared to native EB and decellularized ECM from RA EB. These findings suggest that various treatment conditions allow the formulation of unique ESC-ECM derived scaffolds to enhance ESC bioactivities, including proliferation and differentiation for tissue regeneration applications. © 2013 Goh et al
Person-to-Person Transmission of Severe Fever With Thrombocytopenia Syndrome Bunyavirus Through Blood Contact
Severe fever with thrombocytopenia syndrome bunyavirus is a newly discovered bunyavirus with high pathogenicity to human. The transmission model has been largely uncharacterized. Investigation on a cluster of severe fever with thrombocytopenia syndrome cases provided evidence of person-to-person transmission through blood contact to the index patient with high serum virus load
Measured Dynamic Social Contact Patterns Explain the Spread of H1N1v Influenza
Patterns of social mixing are key determinants of epidemic spread. Here we present the results of an internet-based social contact survey completed by a cohort of participants over 9,000 times between July 2009 and March 2010, during the 2009 H1N1v influenza epidemic. We quantify the changes in social contact patterns over time, finding that school children make 40% fewer contacts during holiday periods than during term time. We use these dynamically varying contact patterns to parameterise an age-structured model of influenza spread, capturing well the observed patterns of incidence; the changing contact patterns resulted in a fall of approximately 35% in the reproduction number of influenza during the holidays. This work illustrates the importance of including changing mixing patterns in epidemic models. We conclude that changes in contact patterns explain changes in disease incidence, and that the timing of school terms drove the 2009 H1N1v epidemic in the UK. Changes in social mixing patterns can be usefully measured through simple internet-based surveys
Social Contact Patterns in Vietnam and Implications for the Control of Infectious Diseases
BACKGROUND: The spread of infectious diseases from person to person is determined by the frequency and nature of contacts between infected and susceptible members of the population. Although there is a long history of using mathematical models to understand these transmission dynamics, there are still remarkably little empirical data on contact behaviors with which to parameterize these models. Even starker is the almost complete absence of data from developing countries. We sought to address this knowledge gap by conducting a household based social contact diary in rural Vietnam. METHODS AND FINDINGS: A diary based survey of social contact patterns was conducted in a household-structured community cohort in North Vietnam in 2007. We used generalized estimating equations to model the number of contacts while taking into account the household sampling design, and used weighting to balance the household size and age distribution towards the Vietnamese population. We recorded 6675 contacts from 865 participants in 264 different households and found that mixing patterns were assortative by age but were more homogenous than observed in a recent European study. We also observed that physical contacts were more concentrated in the home setting in Vietnam than in Europe but the overall level of physical contact was lower. A model of individual versus household vaccination strategies revealed no difference between strategies in the impact on R(0). CONCLUSIONS AND SIGNIFICANCE: This work is the first to estimate contact patterns relevant to the spread of infections transmitted from person to person by non-sexual routes in a developing country setting. The results show interesting similarities and differences from European data and demonstrate the importance of context specific data
Tramtrack Is Genetically Upstream of Genes Controlling Tracheal Tube Size in Drosophila
The Drosophila transcription factor Tramtrack (Ttk) is involved in a wide range of developmental decisions, ranging from early embryonic patterning to differentiation processes in organogenesis. Given the wide spectrum of functions and pleiotropic effects that hinder a comprehensive characterisation, many of the tissue specific functions of this transcription factor are only poorly understood. We recently discovered multiple roles of Ttk in the development of the tracheal system on the morphogenetic level. Here, we sought to identify some of the underlying genetic components that are responsible for the tracheal phenotypes of Ttk mutants. We therefore profiled gene expression changes after Ttk loss- and gain-of-function in whole embryos and cell populations enriched for tracheal cells. The analysis of the transcriptomes revealed widespread changes in gene expression. Interestingly, one of the most prominent gene classes that showed significant opposing responses to loss- and gain-of-function was annotated with functions in chitin metabolism, along with additional genes that are linked to cellular responses, which are impaired in ttk mutants. The expression changes of these genes were validated by quantitative real-time PCR and further functional analysis of these candidate genes and other genes also expected to control tracheal tube size revealed at least a partial explanation of Ttk's role in tube size regulation. The computational analysis of our tissue-specific gene expression data highlighted the sensitivity of the approach and revealed an interesting set of novel putatively tracheal genes
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