3,483 research outputs found

    Appearance of fibronectin during the differentiation of cartilage, bone, and bone marrow.

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    Fibronectin has been localized by indirect immunofluorescence during the various phases of endochondral bone formation in response to subcutaneously implanted demineralized bone matrix. Its histologic appearance has been correlated with results of biosynthetic experiments. (a) The implanted collagenous bone matrix was coated with fibronectin before and during mesenchymal cell proliferation. (b) During proliferation of mesenchymal precursor cells, the newly synthesized extracellular matrix exhibited a fibrillar network of fibronectin. (c) During cartilage differentiation, the fibronectin in the extracellular matrix was apparently masked by proteoglycans, as judged by hyaluronidase treatment. (d) Differentiating chondrocytes exhibited a uniform distribution of fibronectin. (e) Fibronectin was present in a cottony array around osteoblasts during osteogenesis. (f) The developing hematopoietic colonies revealed fibronectin associated with them. Therefore, it appears that fibronectin is ubiquitous throughout the development of endochondral bone and bone marrow

    Controllability and controller-observer design for a class of linear time-varying systems

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    “The final publication is available at Springer via http://dx.doi.org/10.1007/s10852-012-9212-6"In this paper a class of linear time-varying control systems is considered. The time variation consists of a scalar time-varying coefficient multiplying the state matrix of an otherwise time-invariant system. Under very weak assumptions of this coefficient, we show that the controllability can be assessed by an algebraic rank condition, Kalman canonical decomposition is possible, and we give a method for designing a linear state-feedback controller and Luenberger observer

    Treatment-seeking rates in malaria endemic countries

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    BACKGROUND: The proportion of individuals who seek treatment for fever is an important quantity in understanding access to and use of health systems, as well as for interpreting data on disease incidence from routine surveillance systems. For many malaria endemic countries (MECs), treatment-seeking information is available from national household surveys. The aim of this paper was to assemble sub-national estimates of treatment-seeking behaviours and to predict national treatment-seeking measures for all MECs lacking household survey data. METHODS: Data on treatment seeking for fever were obtained from Demographic and Health Surveys, Malaria Indicator Surveys and Multiple Cluster Indicator Surveys for every MEC and year that data were available. National-level social, economic and health-related variables were gathered from the World Bank as putative covariates of treatment-seeking rates. A generalized additive mixed model (GAMM) was used to estimate treatment-seeking behaviours for countries where survey data were unavailable. Two separate models were developed to predict the proportion of fever cases that would seek treatment at (1) a public health facility or (2) from any kind of treatment provider. RESULTS: Treatment-seeking data were available for 74 MECs and modelled for the remaining 24. GAMMs found that the percentage of pregnant women receiving prenatal care, vaccination rates, education level, government health expenditure, and GDP growth were important predictors for both categories of treatment-seeking outcomes. Treatment-seeking rates, which varied both within and among regions, revealed that public facilities were not always the primary facility type used. CONCLUSIONS: Estimates of treatment-seeking rates show how health services are utilized and help correct reported malaria case numbers to obtain more accurate measures of disease burden. The assembled and modelled data demonstrated that while treatment-seeking rates have overall increased over time, access remains low in some malaria endemic regions and utilization of government services is in some areas limited

    Social innovation and its impacts in disadvantaged rural areas: a new evaluation framework

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    An agreed and well-consolidated evaluation framework for the assessment of social innovation (SI) and its impacts has not been developed yet, despite tentative made by scholars (e.g., Nicholls et al. 2015). The EU funded H2020 project SIMRA \u2013 Social Innovation in Marginalised Rural Areas (www.simra-h2020.eu) \u2013 aims to conceptualize an evaluation framework for SI initiatives in disadvantaged rural areas of Europe and non-EU Mediterranean countries. Within SIMRA, SI is defined as \u201cthe reconfiguring of social practices, in response to societal challenges, which seeks to enhance outcomes on societal well-being and necessarily includes the engagement of civil society actors\u201d (Polman et al., 2017). The evaluation framework has been co-constructed with project partners and a panel of international stakeholders in the fields of agriculture, forestry and rural development (Nijnik et al. 2019). It is structured into dimensions and sub-dimensions. It follows the phases of a SI initiative, from the trigger that generates the idea, to the reconfiguring process, and to its impacts. Eight tools for data collection have been developed, tested in pilot cases, and applied in 11 case studies. Empirical results allowed to set 166 indicators: 73 indicators describe the SI dimensions; 63 indicators analyse the process, the project and the whole SI initiative by following relevance, efficiency, effectiveness, impact and sustainability evaluation criteria (OECD, 1991 and 2010); 30 indicators focus on the key aspects of the SI SIMRA definition. Social Network Analysis helps in visualizing the increasing collaborative network of actors involved in the SI process, from core group composed by innovators and followers, to the reconfigured network with new project partners. The approach integrates qualitative-pure methods (e.g., focus group) with quantitative ones. The proposed evaluation framework would like to contribute to current debates, both within the scientific and practitioners\u2019 communities, on evidence-based policy and self-evaluation by rural development agencies

    Lifetime of a target in the presence of N independent walkers

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    We study the survival probability of an immobile target in presence of N independent diffusing walkers. We address the problem of the Mean Target Lifetime and its dependence on the number and initial distribution of the walkers when the trapping is perfect or imperfect. We consider the diffusion on lattices and in the continuous space and we address the bulk limit corresponding to a density of diffusing particles and only one isolated trap. Also, we use intermittent motion for optimization of search strategies.Comment: 18 pages, 5 figures. Accepted for publication in Physica A

    Bulk Mediated Surface Diffusion: Non Markovian Desorption with Finite First Moment

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    Here we address a fundamental issue in surface physics: the dynamics of adsorbed molecules. We study this problem when the particle's desorption is characterized by a non Markovian process, while the particle's adsorption and its motion in the bulk are governed by a Markovian dynamics. We study the diffusion of particles in a semi-infinite cubic lattice, and focus on the effective diffusion process at the interface z=1z = 1. We calculate analytically the conditional probability to find the particle on the z=1z=1 plane as well as the surface dispersion as functions of time. The comparison of these results with Monte Carlo simulations show an excellent agreement.Comment: 16 pages, 7 figs. European Physical Journal B (in press

    Social Innovation in the Mediterranean and how it can help to manage Mediterranean forests

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    This presentation specifies how social innovation initiatives can be promoted in Mediterranean forests. Furthermore, it presents the evaluation methodology proposed for analyzing these initiatives. Preliminary results are also identified and some concluding remarks proposed

    Depression, anxiety, and psychological distress among caregivers of young children in rural Lesotho: Associations with food insecurity, household death and parenting stress

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    Good mental health is a critical resource for mothers and caregivers of young children, given the central role of mental health in enabling responsive caregiving. However, fulfilling caregiving responsibilities under challenging circumstances such as extreme poverty, food insecurity, and gender inequality intensifies vulnerability to poor mental health. Previous research focuses on mental health of mothers, while in many LMICs children are cared for by other caregivers, such as grandparents. We examined the prevalence of mental health problems among primary caregivers of young children in rural Lesotho, and investigated factors associated with these mental health problems. We analysed baseline data from a cluster randomised controlled trial, where all caregivers with children between 1 and 5 years old across 34 villages were invited to participate. The analysis included mental health data from 781 caregivers of 998 children. We assessed caregiver mental health using three self-report screening instruments. Univariate and multivariate regression modelling tested associations between caregiver, child and household variables and (1) depression symptoms (PHQ-9), (2) anxiety symptoms (GAD-7), (3) psychological distress (SRQ-20), (4) suicidal ideation and (5) help-seeking for mental health. This study reported a high prevalence of symptoms of psychological distress (46.2%), depression (25.7%), anxiety (17.1%) and suicidal ideation (27.5%) among caregivers. Greater prevalence was associated with food insecurity, parenting stress or recent death in the family/household. Older caregivers reported higher rates of psychological distress and depression, while younger caregivers reported higher rates of anxiety. Suicidal ideation was associated with greater food insecurity and parenting stress, and lower caregiver education. Our findings support the need to address intersecting public health issues to improve conditions for caregivers in these settings. Targeting modifiable risk factors such as food insecurity among individuals within a society who carry disproportionate burdens of caregiving should be prioritised, especially in contexts of scarcity, where mental health is not prioritised

    The discovery of endogenous retroviruses

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    When endogenous retroviruses (ERV) were discovered in the late 1960s, the Mendelian inheritance of retroviral genomes by their hosts was an entirely new concept. Indeed Howard M Temin's DNA provirus hypothesis enunciated in 1964 was not generally accepted, and reverse transcriptase was yet to be discovered. Nonetheless, the evidence that we accrued in the pre-molecular era has stood the test of time, and our hypothesis on ERV, which one reviewer described as 'impossible', proved to be correct. Here I recount some of the key observations in birds and mammals that led to the discovery of ERV, and comment on their evolution, cross-species dispersion, and what remains to be elucidated
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