465 research outputs found

    Genetic parameters for first lactation dairy traits in the Alpine and Saanen goat breeds using a random regression test-day model

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    International audienceAbstractBackgroundRandom regression models (RRM) are widely used to analyze longitudinal data in genetic evaluation systems because they can better account for time-course changes in environmental effects and additive genetic values of animals by fitting the test-day (TD) specific effects. Our objective was to implement a random regression model for the evaluation of dairy production traits in French goats.ResultsThe data consisted of milk TD records from 30,186 and 32,256 first lactations of Saanen and Alpine goats. Milk yield, fat yield, protein yield, fat content and protein content were considered. Splines were used to model the environmental factors. The genetic and permanent environmental effects were modeled by the same Legendre polynomials. The goodness-of-fit and the genetic parameters derived from functions of the polynomials of orders 0 to 4 were tested. Results were also compared to those from a lactation model with total milk yield calculated over 250 days and to those of a multiple-trait model that considers performance in six periods throughout lactation as different traits. Genetic parameters were consistent between models. Models with fourth-order Legendre polynomials led to the best fit of the data. In order to reduce complexity, computing time, and interpretation, a rank reduction of the variance covariance matrix was performed using eigenvalue decomposition. With a reduction to rank 2, the first two principal components correctly summarized the genetic variability of milk yield level and persistency, with a correlation close to 0 between them.ConclusionsA random regression model was implemented in France to evaluate and select goats for yield traits and persistency, which are independent i.e. no genetic correlation between them, in first lactation

    Elastic, strain-aware physical modeling interface

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    Thesis (S.M.)--Massachusetts Institute of Technology, School of Architecture and Planning, Program in Media Arts and Sciences, 2006.Includes bibliographical references (leaves 56-58).Senspectra is a computationally augmented physical modeling toolkit designed for sensing and visualization of structural strain. The system functions as a distributed sensor network consisting of nodes, embedded with computational capabilities and a full spectrum LED, which communicate to neighbor nodes to determine a network topology through a system of flexible joints. Each joint, while serving as a data and power bus between nodes, also integrates an omnidirectional bend sensing mechanism, which uses a simple optical occlusion technique to sense and communicate mechanical strain between neighboring nodes. Using Senspectra, a user incrementally assembles and refines a physical 3D model of discrete elements with a real-time visualization of structural strain. While the Senspectra infrastructure provides a flexible modular sensor network platform, its primary application derives from the need to couple physical modeling techniques utilized in the architecture and industrial design disciplines with systems for structural engineering analysis, offering an intuitive approach for physical real-time finite element analysis. Utilizing direct manipulation augmented with visual feedback, the system gives users valuable insights on the global behavior of a constructed system defined as a network of discrete elements.by Vincent Leclerc.S.M

    The absence of reactive oxygen species production protects mice against bleomycin-induced pulmonary fibrosis

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    BACKGROUND: Reactive oxygen species and tissue remodeling regulators, such as metalloproteinases (MMPs) and their inhibitors (TIMPs), are thought to be involved in the development of pulmonary fibrosis. We investigated these factors in the fibrotic response to bleomycin of p47(phox )-/- (KO) mice, deficient for ROS production through the NADPH-oxidase pathway. METHODS: Mice are administered by intranasal instillation of 0.1 mg bleomycin. Either 24 h or 14 days after, mice were anesthetized and underwent either bronchoalveolar lavage (BAL) or lung removal. RESULTS: BAL cells from bleomycin treated WT mice showed enhanced ROS production after PMA stimulation, whereas no change was observed with BAL cells from p47(phox )-/- mice. At day 1, the bleomycin-induced acute inflammatory response (increased neutrophil count and MMP-9 activity in the BAL fluid) was strikingly greater in KO than wild-type (WT) mice, while IL-6 levels increased significantly more in the latter. Hydroxyproline assays in the lung tissue 14 days after bleomycin administration revealed the absence of collagen deposition in the lungs of the KO mice, which had significantly lower hydroxyproline levels than the WT mice. The MMP-9/TIMP-1 ratio did not change at day 1 after bleomycin administration in WT mice, but increased significantly in the KO mice. By day 14, the ratio fell significantly from baseline in both strains, but more in the WT than KO strains. CONCLUSIONS: These results suggest that NADPH-oxidase-derived ROS are essential to the development of pulmonary fibrosis. The absence of collagen deposition in KO mice seems to be associated with an elevated MMP-9/TIMP-1 ratio in the lungs. This finding highlights the importance of metalloproteinases and protease/anti-protease imbalances in pulmonary fibrosis

    Neighboring Group Participation and Internal Catalysis Effects on Exchangeable Covalent Bonds: Application to the Thriving Field of Vitrimer Chemistry

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    Vitrimers constitute a fascinating class of polymer materials that make the link between the historically opposed 3D networks (thermosets) and linear polymers (thermoplastics). Their chemical resistance, reshaping ability, and unique rheological behavior upon heating make them promising for future applications in industry. However, many vitrimers require the use of high catalyst loadings, which raises concerns for their durability and limits their potential applications. To cope with this issue, internal catalysis and neighboring group participation (NGP) can be used to enhance the reshaping ability of such materials. A few studies report the effect of activating groups on the exchange reactions in vitrimers. Nevertheless, knowledge on this topic remains scarce, although research on vitrimers would greatly benefit from NGP already known in organic chemistry. The present Perspective presents the different types of exchangeable bonds implemented in vitrimers and discusses chemical groups known to have or potentially capable of an enhancing effect on exchange reactions. This analysis is underpinned by a thorough mechanistic discussion of the various exchangeable bonds presented

    Multi-modeling and co-simulation-based mobile ubiquitous protocols and services development and assessment

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    International audienceMobile and Ubiquitous Computing is about interconnected computing resources embedded in our daily lives and providing contextual services to users. The real influence between user behavior and ubiquitous communication protocols performance and operation needs to be taken into account at the protocol design stage. Therefore, we provide a generic multi-modeling approach that allows us to couple a user behavior model with a network model. To allow both assessment and benchmarking of ubiquitous solutions, we define formal reference scenarios based on the selection of a set of environmental conditions (contexts). We illustrate the use of the framework through its application to the study of mutual influences of mobility models and ad hoc network protocols

    End-of-life care in long-term care homes : a scoping review protocol

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    Background: Quality end-of-life (EOL) care is essential in long-term care homes (LTCHs), as the average survival time of newly admitted residents is estimated to be around 2 to 2.5 years. However, significant challenges exist when it comes to providing EOL clinical care in LTCHs, and the available empirical evidence does not offer a clear idea of the best practices to adopt. Aim: To systematically map the state of knowledge on EOL clinical care in LTCHs, as it relates to people receiving care, family care partners, health care professionals, the characteristics of the organization, the social context, and the implementation of guides. Methods: The scoping review method by Levac et al. (2010) will be used. Data will be collected from multiple sources, including eleven databases using a combination of keywords and descriptors, references list, prospective and manual searches, and by consulting clinicians and managers from LTCHs for additional publications. The literature from 2012 and onwards will be selected if it directly concerns EOL care in LTCHs, with no restriction on the age of residents or on the type of health care professionals or family care partners. The screening and data extraction will be performed by two people independently and any discrepancies will be resolved by consensus. We will also assess the quality of publication with the critical appraisal tools developed by the Joanna Briggs Institute. We will synthesize the extracted data using content analysis and consult stakeholders in LTCHs when a first version of the data synthesis is available to enhance the interpretation of the results based on their experience. We will present results in narrative form with tables and graphs. Discussion: The results will provide evidence-based recommendations for clinical practice when available findings are conclusive and will allow identifying knowledge gaps to orient future research programs focusing specifically on EOL clinical care in LTCHs

    One-Year Safety Analysis of the COMPARE-AMI Trial: Comparison of Intracoronary Injection of CD133+ Bone Marrow Stem Cells to Placebo in Patients after Acute Myocardial Infarction and Left Ventricular Dysfunction

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    Bone marrow stem cell therapy has emerged as a promising approach to improve healing of the infarcted myocardium. Despite initial excitement, recent clinical trials using non-homogenous stem cells preparations showed variable and mixed results. Selected CD133+ hematopoietic stem cells are candidate cells with high potential. Herein, we report the one-year safety analysis on the initial 20 patients enrolled in the COMPARE-AMI trial, the first double-blind randomized controlled trial comparing the safety, efficacy, and functional effect of intracoronary injection of selected CD133+ cells to placebo following acute myocardial infarction with persistent left ventricular dysfunction. At one year, there is no protocol-related complication to report such as death, myocardial infarction, stroke, or sustained ventricular arrhythmia. In addition, the left ventricular ejection fraction significantly improved at four months as compared to baseline and remained significantly higher at one year. These data indicate that in the setting of the COMPARE-AMI trial, the intracoronary injection of selected CD133+ stem cells is secure and feasible in patients with left ventricle dysfunction following acute myocardial infarction
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