151 research outputs found

    Literacy in lockdown: learning and teaching in COVID-19 school closures

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    Across the globe, children have been away from schools and their teachers, but literacy learning has continued. In many countries, children’s literacy proficiency is often measured against high-stakes assessment tests. However, such tests do not make visible children’s literacy lives away from formal learning settings and thus children are positioned as task-responders, rather than as agentive readers and writers. This article explores the fluidity and diversity of literacy events and practices for students, children and their teachers observed during the recent period of Covid-19 lockdown restrictions

    Long-term Outcome after Surgical Closure of Atrial Septal Defect in Childhood with Extensive Assessment Including MRI Measurement of the Ventricles

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    Surgical closure of the secundum type of atrial septal defect (ASD) in childhood leads to excellent survival. However, relevant morbidity has been reported. Transcatheter closure of these defects has now become an alternative approach. To compare the results of the two different interventions, reliable data are needed on the long-term morbidity after defect closure with both methods. Patients were evaluated after a minimum of 10 years after surgical closure of an ASD in childhood. Assessment included analysis of perioperative data, interview, clinical examination, electrocardiogram, (ECG), 24-hour ECG, ergometry, chest radiograph, echocardiography, and MRI. A total of 66 patients underwent operation between 1971 and 1986 at our institution. Forty-eight of them (73%) were interviewed and 38 (58%) participated fully in the study program. Eighteen (27%) either refused to participate or were lost to follow-up. There were no substantial residual disorders, such as arrhythmias, right-sided heart dilatation, pulmonary hypertension, or reduced work capacity. Surgical closure of an ASD in childhood has an excellent long-term outcome. Surgical closure is thus the standard against which transcatheter closure needs to be measure

    Human Galectins Induce Conversion of Dermal Fibroblasts into Myofibroblasts and Production of Extracellular Matrix: Potential Application in Tissue Engineering and Wound Repair

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    Members of the galectin family of endogenous lectins are potent adhesion/growth-regulatory effectors. Their multi-functionality opens possibilities for their use in bioapplications. We studied whether human galectins induce the conversion of human dermal fibroblasts into myofibroblasts (MFBs) and the production of a bioactive extracellular matrix scaffold is suitable for cell culture. Testing a panel of galectins of all three subgroups, including natural and engineered variants, we detected activity for the proto-type galectin-1 and galectin-7, the chimera-type galectin-3 and the tandem-repeat-type galectin-4. The activity of galectin-1 required the integrity of the carbohydrate recognition domain. It was independent of the presence of TGF-beta 1, but it yielded an additive effect. The resulting MFBs, relevant, for example, for tumor progression, generated a matrix scaffold rich in fibronectin and galectin-1 that supported keratinocyte culture without feeder cells. Of note, keratinocytes cultured on this substratum presented a stem-like cell phenotype with small size and keratin-19 expression. In vivo in rats, galectin-1 had a positive effect on skin wound closure 21 days after surgery. In conclusion, we describe the differential potential of certain human galectins to induce the conversion of dermal fibroblasts into MFBs and the generation of a bioactive cell culture substratum. Copyright (C) 2011 S. Karger AG, Base

    Thermochemistry of Alane Complexes for Hydrogen Storage: A Theoretical and Experimental Comparison

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    Knowledge of the relative stabilities of alane (AlH3) complexes with electron donors is essential for identifying hydrogen storage materials for vehicular applications that can be regenerated by off-board methods; however, almost no thermodynamic data are available to make this assessment. To fill this gap, we employed the G4(MP2) method to determine heats of formation, entropies, and Gibbs free energies of formation for thirty-eight alane complexes with NH3-nRn (R = Me, Et; n = 0-3), pyridine, pyrazine, triethylenediamine (TEDA), quinuclidine, OH2-nRn (R = Me, Et; n = 0-2), dioxane, and tetrahydrofuran (THF). Monomer, bis, and selected dimer complex geometries were considered. Using these data, we computed the thermodynamics of the key formation and dehydrogenation reactions that would occur during hydrogen delivery and alane regeneration, from which trends in complex stability were identified. These predictions were tested by synthesizing six amine-alane complexes involving trimethylamine, triethylamine, dimethylethylamine, TEDA, quinuclidine, and hexamine, and obtaining upper limits of delta G for their formation from metallic aluminum. Combining these computational and experimental results, we establish a criterion for complex stability relevant to hydrogen storage that can be used to assess potential ligands prior to attempting synthesis of the alane complex. Based on this, we conclude that only a subset of the tertiary amine complexes considered and none of the ether complexes can be successfully formed by direct reaction with aluminum and regenerated in an alane-based hydrogen storage system.Comment: Accepted by the Journal of Physical Chemistry

    Statistical analysis plan for cluster randomised trial to evaluate a community-level complementary food safety and hygiene and nutrition intervention in Mali:the MaaCiwara study

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    Background: Diarrheal disease is a significant cause of morbidity and mortality in under-fives in many low- and middle-income countries. Changes in food safety, hygiene practices, and nutrition around the weaning period may reduce the risk of disease and improve infant development. The MaaCiwara study aims to evaluate the effectiveness of a community-based educational intervention designed to improve food safety and hygiene behaviours, as well as child nutrition. This update article describes the statistical analysis plan for the MaaCiwara study in detail. Methods and design: The MaaCiwara study is a parallel group, two-arm, superiority cluster randomised controlled trial with baseline measures, involving 120 clusters of rural and urban communities. These clusters are randomised to either receive the community-based behaviour change intervention or to the control group. The study participants will be mother–child pairs, with children aged between 6 and 36 months. Data collection involves a day of observation and interviews with each participating mother–child pair, conducted at baseline, 4 months, and 15 months post-intervention. The primary analysis aims to estimate the effectiveness of the intervention on changes to complementary food safety and preparation behaviours, food and water contamination, and diarrhoea. The primary outcomes will be analysed generalised linear mixed models, at individual level, accounting for clusters and rural/urban status to estimate the difference in outcomes between the intervention and control groups. Secondary outcomes include maternal autonomy, enteric infection, nutrition, child anthropometry, and development scores. In addition, structural equation analysis will be conducted to examine the causal relationships between the different outcomes. Trial registration: International Standard Randomised Controlled Trial Number (ISRCTN) register: ISRCTN14390796. Registered on 13 December 2021

    Donor genetic determinant of thymopoiesis, rs2204985, and stem cell transplantation outcome in a multipopulation cohort

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    \ua9 2024 The Author(s)Background: A genetic polymorphism, rs2204985, has been reported to be associated with the diversity of T-cell antigen receptor repertoire and TREC levels, reflecting the function of the thymus. As the thymus function can be assumed to be an important factor regulating the outcome of stem cell transplantation (SCT), it was of great interest that rs2204985 showed a genetic association to disease-free and overall survival in a German SCT donor cohort. Tools to predict the outcome of SCT more accurately would help in risk assessment and patient safety. Objective: To evaluate the general validity of the original genetic association found in the German cohort, we determined genetic associations between rs2204985 and the outcome of SCT in 1,473 SCT donors from four different populations. Study design: Genetic associations between rs2204985 genotype AA versus AG/GG and overall survival (OS) and disease-free survival (DFS) in 1,473 adult, allogeneic SCT from Finland, the United Kingdom, Spain, and Poland were performed using the Kaplan-Meier analysis and log-rank tests. We adjusted the survival models with covariates using Cox regression. Results: In unrelated SCT donors (N = 425), the OS of genotype AA versus AG/GG had a trend for a similar association (p = 0.049, log-rank test) as previously reported in the German cohort. The trend did not remain significant in the Cox regression analysis with covariates. No other associations were found. Conclusion: Weak support for the genetic association between rs2204985, previously also associated with thymus function, and the outcome of SCT could be found in a cohort from four populations

    The developmental dynamics of terrorist organizations

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    We identify robust statistical patterns in the frequency and severity of violent attacks by terrorist organizations as they grow and age. Using group-level static and dynamic analyses of terrorist events worldwide from 1968-2008 and a simulation model of organizational dynamics, we show that the production of violent events tends to accelerate with increasing size and experience. This coupling of frequency, experience and size arises from a fundamental positive feedback loop in which attacks lead to growth which leads to increased production of new attacks. In contrast, event severity is independent of both size and experience. Thus larger, more experienced organizations are more deadly because they attack more frequently, not because their attacks are more deadly, and large events are equally likely to come from large and small organizations. These results hold across political ideologies and time, suggesting that the frequency and severity of terrorism may be constrained by fundamental processes.Comment: 28 pages, 8 figures, 4 tables, supplementary materia

    3D pic simulations of collisionless shocks at lunar magnetic anomalies and their role in forming lunar swirls

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    The authors would like to thank the Science and Technology Facilities Council for fundamental physics and computing resources that were provided by funding from STFC’s Scientific Computing Department, and would like to thank the European Research Council (ERC 2010 AdG Grant 267841) and FCT (Portugal) grants SFRH/BD/75558/2010 for support.Investigation of the lunar crustal magnetic anomalies offers a comprehensive long-term data set of observations of small-scale magnetic fields and their interaction with the solar wind. In this paper a review of the observations of lunar mini-magnetospheres is compared quantifiably with theoretical kinetic-scale plasma physics and 3D particle-in-cell simulations. The aim of this paper is to provide a complete picture of all the aspects of the phenomena and to show how the observations from all the different and international missions interrelate. The analysis shows that the simulations are consistent with the formation of miniature (smaller than the ion Larmor orbit) collisionless shocks and miniature magnetospheric cavities, which has not been demonstrated previously. The simulations reproduce the finesse and form of the differential proton patterns that are believed to be responsible for the creation of both the "lunar swirls" and "dark lanes." Using a mature plasma physics code like OSIRIS allows us, for the first time, to make a side-by-side comparison between model and space observations. This is shown for all of the key plasma parameters observed to date by spacecraft, including the spectral imaging data of the lunar swirls. The analysis of miniature magnetic structures offers insight into multi-scale mechanisms and kinetic-scale aspects of planetary magnetospheres.Publisher PDFPeer reviewe
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