44 research outputs found

    Reliable multicast in heterogeneous mobile ad-hoc networks

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    In disaster scenarios, communication infrastructure could be damaged or completely failed. Mobile Ad-hoc Networks (MANETs) can be used to substitute failed communication devices and thus to enable communication. As group communication is an important part in disaster scenarios, multicast will be used to address several nodes. In this paper, we propose our new reliable multicast protocol RMDA (Reliable Multicast over Delay Tolerant Mobile Ad hoc Networks). We introduce an efficient group management approach and a new method for reliable multicast delivery over Delay Tolerant Networks. We show, that our protocol is adaptive to different kinds of MANETs, e.g. with or without clusterheads, respectively. For those without, we use our name resolution over adaptive routing approach

    Therapeutic and prophylactic effect of intermittent preventive anti-malarial treatment in infants (IPTi) from Ghana and Gabon

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    <p>Abstract</p> <p>Background</p> <p>Intermittent preventive treatment in infants (IPTi) with sulphadoxine-pyrimethamine (SP) reduces the incidence of malaria episodes in young children. The exact mechanism by which the protective effect is mediated needs to be defined. This study aimed to investigate therapeutic, prophylactic, and possible exceeding effects of SP-based IPTi in two clinical trials.</p> <p>Methods</p> <p>Protective efficacies from two IPTi trials performed in Kumasi, Ghana, and Lambaréné, Gabon, were assessed for overlapping time series of 61 days. For six-months periods after each of three IPTi doses a multivariate Poisson regression model with the respective cohort as co-variate was generated and effect modification of protective efficacy with time strata was evaluated by log-likelihood tests.</p> <p>Results</p> <p>Protective efficacies were not significantly different between the two study cohorts. Study-cohort corrected protective efficacy was highest for the first 61 days after each IPTi application and decreased continuously. For the first 61 days after IPTi-1, IPTi-2, and IPTi-3 the protective efficacy was 71%, 44%, and 43%, respectively. A reduction of the malaria incidence rate was detectable for the first 60, 30 and 40 days after IPTi-1, IPTi-2 and IPTi-3 drug application, respectively. After IPTi-3 a higher risk for malaria could be seen after day 60. This effect was mainly based on the overwhelming influence of the Kumasi cohort.</p> <p>Conclusion</p> <p>The results suggest that SP-based IPTi mainly works through a therapeutic and prophylactic effect over 30 to 60 days after drug application and that a sustained effect beyond post-treatment prophylaxis might be very low.</p> <p>Trial registration</p> <p>Data analysis from clinical trials NCT ID # 00206739 (Kumasi Trial) and NCT ID # 00167843 (Lambaréné Trial), <url>http://www.clinicaltrials.gov</url>.</p

    Predictive Value of Fever and Palmar Pallor for P. falciparum Parasitaemia in Children from an Endemic Area

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    INTRODUCTION: Although the incidence of Plasmodium falciparum malaria in some parts of sub-Saharan Africa is reported to decline and other conditions, causing similar symptoms as clinical malaria are gaining in relevance, presumptive anti-malarial treatment is still common. This study traced for age-dependent signs and symptoms predictive for P. falciparum parasitaemia. METHODS: In total, 5447 visits of 3641 patients between 2-60 months of age who attended an outpatient department (OPD) of a rural hospital in the Ashanti Region, Ghana, were analysed. All Children were examined by a paediatrician and a full blood count and thick smear were done. A Classification and Regression Tree (CART) model was used to generate a clinical decision tree to predict malarial parasitaemia a7nd predictive values of all symptoms were calculated. RESULTS: Malarial parasitaemia was detected in children between 2-12 months and between 12-60 months of age with a prevalence of 13.8% and 30.6%, respectively. The CART-model revealed age-dependent differences in the ability of the variables to predict parasitaemia. While palmar pallor was the most important symptom in children between 2-12 months, a report of fever and an elevated body temperature of ≥37.5°C gained in relevance in children between 12-60 months. The variable palmar pallor was significantly (p<0.001) associated with lower haemoglobin levels in children of all ages. Compared to the Integrated Management of Childhood Illness (IMCI) algorithm the CART-model had much lower sensitivities, but higher specificities and positive predictive values for a malarial parasitaemia. CONCLUSIONS: Use of age-derived algorithms increases the specificity of the prediction for P. falciparum parasitaemia. The predictive value of palmar pallor should be underlined in health worker training. Due to a lack of sensitivity neither the best algorithm nor palmar pallor as a single sign are eligible for decision-making and cannot replace presumptive treatment or laboratory diagnosis

    New insights into the genetic etiology of Alzheimer's disease and related dementias

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    Characterization of the genetic landscape of Alzheimer's disease (AD) and related dementias (ADD) provides a unique opportunity for a better understanding of the associated pathophysiological processes. We performed a two-stage genome-wide association study totaling 111,326 clinically diagnosed/'proxy' AD cases and 677,663 controls. We found 75 risk loci, of which 42 were new at the time of analysis. Pathway enrichment analyses confirmed the involvement of amyloid/tau pathways and highlighted microglia implication. Gene prioritization in the new loci identified 31 genes that were suggestive of new genetically associated processes, including the tumor necrosis factor alpha pathway through the linear ubiquitin chain assembly complex. We also built a new genetic risk score associated with the risk of future AD/dementia or progression from mild cognitive impairment to AD/dementia. The improvement in prediction led to a 1.6- to 1.9-fold increase in AD risk from the lowest to the highest decile, in addition to effects of age and the APOE ε4 allele

    Some like it hot? Developmental differences in yellow-bellied toad tadpoles (Bombina variegata) from geographically close but different habitats

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    The key for the long-term survival of species is their potential to respond to changing conditions. These reactions are usually species-specific and may vary between populations. The yellow-bellied toad, Bombina variegata (L., 1758), occurs in forested and open areas. We wanted to know whether tadpoles react plastically to different environmental conditions – and if so, whether reaction norms are species-, population- or season-specific. In a common garden experiment we compared developmental traits (developmental time, size, body-condition) of metamorphs from different habitats (forest versus quarry) in close geographic proximity. Tadpoles from both habitats grew up under shaded and sunny conditions. The experiments were run during early and late breeding season. We detected different developmental strategies between populations, concerning treatments and season on a microgeographic scale. Tadpoles with quarry origin developed faster and reached larger body sizes, at the expense of lower body-condition. Major risks affecting tadpole´s survival in the open habitat are high temperatures and high desiccation. Forest tadpoles were comparatively smaller in size, but showed higher plasticity and higher body-condition. Under changing climatic conditions quarry population may reach temperatures above their thermal limits. In contrast forest conditions may mitigate increasing temperatures. Forest populations could be better adapted to future climate change.The accepted manuscript in pdf format is listed with the files at the bottom of this page. The presentation of the authors' names and (or) special characters in the title of the manuscript may differ slightly between what is listed on this page and what is listed in the pdf file of the accepted manuscript; that in the pdf file of the accepted manuscript is what was submitted by the author

    Strain Echocardiography in Acute COVID-19 and Post-COVID Syndrome: More than Just a Snapshot

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    Speckle-tracking echocardiography (STE) has become an established, widely available diagnostic method in the past few years, making its value clear in cases of COVID-19 and the further course of the disease, including post-COVID syndrome. Since the beginning of the pandemic, many studies have been published on the use of STE in this condition, enabling, on the one hand, a better understanding of myocardial involvement in COVID-19 and, on the other, a better identification of risk to patients, although some questions remain unanswered in regard to specific pathomechanisms, especially in post-COVID patients. This review takes a closer look at current findings and potential future developments by summarising the extant data on the use of STE, with a focus on left and right ventricular longitudinal strain
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