A CRC usefulness assessment for adaptation layers in satellite systems

This paper assesses the real usefulness of CRCs in today's satellite network-to-link adaptation layers under the lights of enhanced error control and framing techniques, focusing on the DVB-S and DVB-S2 standards. Indeed, the outer block codes of their FEC schemes (Reed-Solomon and BCH, respectively) can provide very accurate error-detection information to the receiver in addition to their correction capabilities, at virtually no cost. This handy feature could be used to manage on a frame-by-frame basis what CRCs do locally, on the frames' contents, saving the bandwidth and processing load associated with them, and paving the way for enhanced transport of IP over DVB-S2. Mathematical and experimental results clearly show that if FEC has been properly congured for combined error correction and detection, having an uncorrected event after FEC decoding is likely to be an extremely improbable event. Under such conditions, it seems possible and attractive to optimize the way global error-control is done over satellite links by reducing the role of CRCs, or even by removing them from the overall encapsulation process

Design issues for the Generic Stream Encapsulation (GSE) of IP datagrams over DVB-S2

The DVB-S2 standard has brought an unprecedented degree of novelty and flexibility in the way IP datagrams or other network level packets can be transmitted over DVB satellite links, with the introduction of an IP-friendly link layer - he continuous Generic Streams - and the adaptive combination of advanced error coding, modulation and spectrum management techniques. Recently approved by the DVB, the Generic Stream Encapsulation (GSE) used for carrying IP datagrams over DVBS2 implements solutions stemmed from a design rationale quite different from the one behind IP encapsulation schemes over its predecessor DVB-S. This paper highlights GSE's original design choices under the perspective of DVB-S2's innovative features and possibilities

Relation between mean arterial pressure and renal function in the early phase of shock: a prospective, explorative cohort study

International audienceIntroduction: Because of disturbed renal autoregulation, patients experiencing hypotension-induced renal insult might need higher levels of mean arterial pressure (MAP) than the 65 mmHg recommended level in order to avoid the progression of acute kidney insufficiency (AKI)

Prevalence and incidence of antibodies against SARS-CoV-2 among primary healthcare providers in Belgium during 1 year of the COVID-19 epidemic: prospective cohort study protocol.

peer reviewed[en] INTRODUCTION: National SARS-CoV-2 seroprevalence data provide essential information about population exposure to the virus and help predict the future course of the epidemic. Early cohort studies have suggested declines in levels of antibodies in individuals associated with, for example, illness severity, age and comorbidities. This protocol focuses on the seroprevalence among primary healthcare providers (PHCPs) in Belgium. PHCPs manage the vast majority of (COVID-19) patients and therefore play an essential role in the efficient organisation of healthcare. Currently, evidence is lacking on (1) how many PHCPs get infected with SARS-CoV-2 in Belgium, (2) the rate at which this happens, (3) their clinical spectrum, (4) their risk factors, (5) the effectiveness of the measures to prevent infection and (6) the accuracy of the serology-based point-of-care test (POCT) in a primary care setting. METHODS AND ANALYSIS: This study will be set up as a prospective cohort study. General practitioners (GPs) and other PHCPs (working in a GP practice) will be recruited via professional networks and professional media outlets to register online to participate. Registered GPs and other PHCPs will be asked at each testing point (n=9) to perform a capillary blood sample antibody POCT targeting IgM and IgG against the receptor-binding domain of SARS-CoV-2 and complete an online questionnaire. The primary outcomes are the prevalence and incidence of antibodies against SARS-CoV-2 in PHCPs during a 12-month follow-up period. Secondary outcomes include the longevity of antibodies against SARS-CoV-2. ETHICS AND DISSEMINATION: Ethical approval has been granted by the ethics committee of the University Hospital of Antwerp/University of Antwerp (Belgian registration number: 3002020000237). Alongside journal publications, dissemination activities include the publication of monthly reports to be shared with the participants and the general population through the publicly available website of the Belgian health authorities (Sciensano). TRIAL REGISTRATION NUMBER: NCT04779424

Validation of a rapid SARS-CoV-2 antibody test in general practice.

peer reviewed[en] OBJECTIVES: To validate a rapid serological test (RST) for SARS-CoV-2 antibodies used in seroprevalence studies in healthcare providers, including primary healthcare providers (PHCPs) in Belgium. DESIGN: A phase III validation study of the RST (OrientGene) within a prospective cohort study. SETTING: Primary care in Belgium. PARTICIPANTS: Any general practitioner (GP) working in primary care in Belgium and any other PHCP from the same GP practice who physically manages patients were eligible in the seroprevalence study. For the validation study, all participants who tested positive (376) on the RST at the first testing timepoint (T1) and a random sample of those who tested negative (790) and unclear (24) were included. INTERVENTION: At T2, 4 weeks later, PHCPs performed the RST with fingerprick blood (index test) immediately after providing a serum sample to be analysed for the presence of SARS-CoV-2 immunoglobulin G antibodies using a two-out-of-three assay (reference test). PRIMARY AND SECONDARY OUTCOME MEASURES: The RST accuracy was estimated using inverse probability weighting to correct for missing reference test data, and considering unclear RST results as negative for the sensitivity and positive for the specificity. Using these conservative estimates, the true seroprevalence was estimated both for T2 and RST-based prevalence values found in a cohort study with PHCPs in Belgium. RESULTS: 1073 paired tests (403 positive on the reference test) were included. A sensitivity of 73% (a specificity of 92%) was found considering unclear RST results as negative (positive). For an RST-based prevalence at T1 (13.9), T2 (24.9) and T7 (70.21), the true prevalence was estimated to be 9.1%, 25.9% and 95.7%, respectively. CONCLUSION: The RST sensitivity (73%) and specificity (92%) make an RST-based seroprevalence below (above) 23% overestimate (underestimate) the true seroprevalence. TRIAL REGISTRATION NUMBER: NCT04779424

Between but not within species variation in the distribution of fitness effects

New mutations provide the raw material for evolution and adaptation. The distribution of fitness effects (DFE) describes the spectrum of effects of new mutations that can occur along a genome, and is therefore of vital interest in evolutionary biology. Recent work has uncovered striking similarities in the DFE between closely related species, prompting us to ask whether there is variation in the DFE among populations of the same species, or among species with different degrees of divergence, i.e., whether there is variation in the DFE at different levels of evolution. Using exome capture data from six tree species sampled across Europe we characterised the DFE for multiple species, and for each species, multiple populations, and investigated the factors potentially influencing the DFE, such as demography, population divergence and genetic background. We find statistical support for there being variation in the DFE at the species level, even among relatively closely related species. However, we find very little difference at the population level, suggesting that differences in the DFE are primarily driven by deep features of species biology, and that evolutionarily recent events, such as demographic changes and local adaptation, have little impact

Genetic analysis of organoleptic quality in fresh market tomato. 2. Mapping QTLs for sensory attributes

International audienc