A Comparison of Selected GBN ARQ Schemes for Variable-Error-Rate Channel Using QAM

In non-stationary channels, error rates vary considerably. The paper compares Yao's Adaptive Go-back-N (GBN) Automatic-Repeat-Request (ARQ) scheme with Adaptive go-back-N with sliding window mechanism which both estimate the channel state in a simple manner, and adaptively switch their operation mode. The throughput of these schemes is compared in conditions of Additive White Gauss Noise (AWGN) channel with independent errors using 16-QAM modulation

Recovery of Extra-Radical Fungal Peptides Amenable for Shotgun Protein Profiling in Arbuscular Mycorrhizae

International audienceIn arbuscular mycorrhizal symbiosis, the belowground mycelium that develops into the soil, not only provides extensive pathways for nutrient fluxes, the occupation of different niches, and dispersal of propagules, but also has strong influences upon biogeochemical cycling. By providing a valuable overview of expression changes of most proteins, shotgun proteomics can help decipher key metabolic pathways involved in the functioning of fungal mycelia. In this protocol, we describe the combination of extra-radical mycelium growth systems with gel-based extraction of fungal peptides amenable for shotgun protein profiling, which allows gaining information about the extra-radical proteom

Measuring discrimination experienced by people with a mental illness: Replication of the short-form DISCUS in six world regions

Background The Discrimination and Stigma Scale (DISC) is a patient-reported outcome measure which assesses experiences of discrimination among persons with a mental illness globally. Methods This study evaluated whether the psychometric properties of a short-form version, DISC-Ultra Short (DISCUS) (11-item), could be replicated in a sample of people with a wide range of mental disorders from 21 sites in 15 countries/territories, across six global regions. The frequency of experienced discrimination was reported. Scaling assumptions (confirmatory factor analysis, inter-item and item-total correlations), reliability (internal consistency) and validity (convergent validity, known groups method) were investigated in each region, and by diagnosis group. Results 1195 people participated. The most frequently reported experiences of discrimination were being shunned or avoided at work (48.7%) and discrimination in making or keeping friends (47.2%). Confirmatory factor analysis supported a unidimensional model across all six regions and five diagnosis groups. Convergent validity was confirmed in the total sample and within all regions [ Internalised Stigma of Mental Illness (ISMI-10): 0.28-0.67, stopping self: 0.54-0.72, stigma consciousness: -0.32-0.57], as was internal consistency reliability (α = 0.74-0.84). Known groups validity was established in the global sample with levels of experienced discrimination significantly higher for those experiencing higher depression [Patient Health Questionnaire (PHQ)-2: p < 0.001], lower mental wellbeing [Warwick-Edinburgh Well-being Scale (WEMWBS): p < 0.001], higher suicidal ideation [Beck Hopelessness Scale (BHS)-4: p < 0.001] and higher risk of suicidal behaviour [Suicidal Ideation Attributes Scale (SIDAS): p < 0.001]. Conclusions The DISCUS is a reliable and valid unidimensional measure of experienced discrimination for use in global settings with similar properties to the longer DISC. It offers a brief assessment of experienced discrimination for use in clinical and research settings

Characteristics of the freshwater cyanobacterium Microcystis aeruginosa grown in iron-limited continuous culture

A continuous culturing system (chemostat) made of metal-free materials was successfully developed and used to maintain Fe-limited cultures of Microcystis aeruginosa PCC7806 at nanomolar iron (Fe) concentrations (20 to 50 nM total Fe). EDTA was used to maintain Fe in solution, with bioavailable Fe controlled by absorption of light by the ferric EDTA complex and resultant reduction of Fe(III) to Fe(II). A kinetic model describing Fe transformations and biological uptake was applied to determine the biologically available form of Fe (i.e., unchelated ferrous iron) that is produced by photoreductive dissociation of the ferric EDTA complex. Prediction by chemostat theory modified to account for the light-mediated formation of bioavailable Fe rather than total Fe was in good agreement with growth characteristics of M. aeruginosa under Fe limitation. The cellular Fe quota increased with increasing dilution rates in a manner consistent with the Droop theory. Short-term Fe uptake assays using cells maintained at steady state indicated that M. aeruginosa cells vary their maximum Fe uptake rate (ρmax) depending on the degree of Fe stress. The rate of Fe uptake was lower for cells grown under conditions of lower Fe availability (i.e., lower dilution rate), suggesting that cells in the continuous cultures adjusted to Fe limitation by decreasing ρmax while maintaining a constant affinity for Fe