Comparaison de deux méthodes d'estimation du broutage des bactéries par les protozoaires en milieux aquatiques [Courte note]

L'objectif du présent travail est de comparer deux méthodes indépendantes permettant d'estimer, dans les milieux aquatiques, le flux de carbone transitant du compartiment bactérien vers les protozoaires. Les deux méthodes utilisées sont, d'une part, celle basée sur le suivi de la décroissance de radioactivité du matériel génétique bactérien après marquage à la thymidine tritiée (SERVAIS et al., 1985) et, d'autre part, celle de mesure du taux d'ingestion de bactéries fluorescentes (FLB) par les protozoaires. Elles ont été appliquées en parallèle sur des échantillons de la rivière Meuse (Belgique). L'emploi de la première méthode a montré des taux de broutage compris entre 0.002 h-1 et 0.016 h-1 qui représentent en moyenne 72 % des taux de mortalité totale. Une excellente corrélation entre les estimations de flux de broutage obtenues par les deux techniques a été trouvée, mais les valeurs estimées à partir de la méthode FLB sont systématiquement inférieures (d'environ 30% en moyenne) à celles obtenues par l'autre méthode. Une part de cette différence peut vraisemblablement s'expliquer par la non prise en compte par la méthode FLB du broutage par des organismes de taille supérieure à 100 µm.The goal of the present work was to compare two methods allowing to estimate, in aquatic ecosystems, the carbon flux due to grazing of bacteria by protozoa. The first method follows the decrease of labeling in the DNA of natural assemblages of bacteria previously labeled with tritiated thymidine (SERVAIS et al., 1985) and the second procedure is based on the estimation of bacterial ingestion rate by protozoa using fluorescently labeled bacteria (FLB). Both methods were applied in parallel on river Meuse (Belgium) samples. Using the first method, grazing rates in the range 0.002 h-1 to 0.016 h-1 were observed; they represented in average 72 % of the total bacterial mortality rates. A very good correlation between both estimates of the grazing fluxes was found but the data obtained by the FLB method were systematically lower (around 30% in average) than those estimated with the other method. A part of this difference is probably due to he fact that the FLB method does not take into account grazing by organism higher than 100 µm

Adult onset thalamocerebellar degeneration in dogs associated to neuronal storage of ceroid lipopigment

Late onset of hereditary cerebellar cortical abiotrophy has been described in a large variety of canine breeds. In some reported conditions, the cerebellar lesion is combined with degeneration of other systems. Here we describe a new hereditary cerebellar cortical degeneration in eight adult American Staffordshire and Pit Bull Terriers. The neuronal degeneration in these animals not only affects Purkinje cells of the cerebellum but also certain thalamic nuclei. In addition, nerve cell loss appears to be associated with a lysosomal storage disease, which is restricted to the affected cell populations. The stored material was histologically and ultrastructurally identified as fluorescent lipopigment. Since animals were euthanized at various stages of the disease, it could be shown that lysosomal storage preceded neuronal loss. Selective involvement of restricted neuronal populations is highly unusual in ceroid lipofuscinoses. It remains to be determined if the present neurodegenerative disease is caused by a primary or secondary neuronal ceroid lipofuscinosi

Opinie-onderzoek over verschillen tussen openbare en private Vlaamse ziekenhuizen.

Uit vroegere studies bleek dat algemeen directeurs van Vlaamse openbare en private ziekenhuizen een eenheidsstatuut nastreven. Met een eenheidsstatuut wordt in het algemeen een situatie bedoeld waarbij de regelgeving voor alle ziekenhuizen dusdanig is dat noch de openbare noch de private ziekenhuizen zich bevoordeeld of benadeeld voelen tegenover elkaar bij het aanbieden van de zorg. Dit kan zowel verband houden met het juridisch statuut als met de regelgeving over financiering, personeel enz.. Een mogelijk eenheidsstatuut zal wellicht makkelijker tot stand komen als openbare en private ziekenhuizen een zelfde visie delen over een aantal beleidstopics. Het leek ons daarom interessant om via een opinie-onderzoek na te gaan hoe ziekenhuizen met een openbaar of een privaat karakter dezelfde of verschillende meningen hebben over elkaar wat betreft hun juridisch statuut, personeelsbeleid, mogelijke samenwerking, ziekenhuisfinanciering en toegankelijkheid. Alhoewel de resultaten aanduiden dat beide types ziekenhuizen, anno 2003, sterk te vinden zijn voor een eenheidsstatuut blijken er heel wat meningverschillen te bestaan over een aantal belangrijke beleidstopics.Studies;

Agricultural extension messages using video on portable devices increase knowledge about seed selection, storage and handling among smallholder potato farmers in southwestern Uganda

Open Access JournalTo feed a growing population, agricultural productivity needs to increase dramatically. Agricultural extension information, with its public, non-rival nature, is generally undersupplied, and public provision remains challenging. In this study, simple agricultural extension video messages, delivered through Android tablets, were tested in the field to determine if they increased farmers’ knowledge of recommended practices on (i) potato seed selection and (ii) seed storage and handling among a sample of potato farmers in southwestern Uganda. Using a field experiment with ex ante matching in a factorial design, it was established that showing agricultural extension videos significantly increased farmers’ knowledge. However, results suggested impact pathways that went beyond simply replicating what was shown in the video. Video messages may have triggered a process of abstraction, whereby farmers applied insights gained in one context to a different context

The opportunities of two-phase hybrid stepping motor back EMF sampling

By counting the step command pulses, stepping motors can be straightforwardly used for open loop positioning. However, open-loop control is often insufficient to guarantee accurate and energy efficient movements. More intelligent stepping motor algorithms can meet these concerns, however, this requires position information. The back EMF signal contains useful information on the rotor position. This information can be used to monitor the motor condition and to implement a more advanced position control algorithm. A theoretical analysis gives insight into the back EMF generated in a two-phase hybrid stepping motor. In this paper a, by the authors, patented sampling method is considered to measure the back EMF signal. The opportunities of this method are considered theoretically. Moreover this paper presents extensive measurement results proving the opportunities of the method, to develop more intelligent stepping motor algorithms

Subsurface chlorophyll maximum and hydrodynamics of the water column

The vertical distributions of chlorophyll a (in vivo fluorescence) and hydrodynamic properties were monitored in the Gulf of St. Lawrence (Canada) from 6 to 10 August 1983, using an automatic yo-yo profiling system and a chain of 4 current meters. Spectral analyses of temperature and in vivo fluorescence series showed that dominant frequencies were associated with internal waves (∼16 h inertial frequency). A subsurface chlorophyll maximum was continuously observed in the lower part of the 20 m thick photic layer, at a depth corresponding with maximum vertical stability of the water column, just above the nutricline.The depth of maximum phytoplankton production, at least on sunny days, corresponded to that of the subsurface chlorophyll maximum and of the maximum in vertical stability. This close association persisted despite strong horizontal advection and vertical movements caused by internal waves. Photosynthetic adjustment did occur in the water column: higher vertical stability at depth favored shade adaptation of the phytoplankton in the layer of maximum stability, as compared to the more light-adapted cells of the upper well-mixed layer. At our sampling station, vertical turbulent diffusion seemed to be high enough to replenish nutrients in the photic layer, so that they never became completely exhausted, even in surface waters. Therefore, the observed subsurface chlorophyll maximum not only resulted from environmental conditions more favorable for phytoplankton accumulation and growth, but it also involved active photosynthetic responses of phytoplankton

BSR Spondyloarthritis Course, 27 February 2020. Spondyloarthritis: pathogenesis, diagnosis and management

High-quality continuous medical education is essential to maintain excellence in health-care delivery, upskilling professionals and improving patient outcomes. This is particularly relevant when addressing rare disease groups, such as the spondyloarthritides, a group of heterogeneous inflammatory conditions that affect joints and other organs, such as the skin, bowel and eye. Professional bodies, such as the British Society for Rheumatology (BSR), are well placed to deliver this type of education. In 2020, the BSR ran a dedicated SpA course aimed at rheumatology health-care professionals wishing to update their basic knowledge of SpA with a review of the latest advances in the field. Here, we summarize the proceedings of the meeting and discuss the value of such an initiative

Semiquantitative interpretation of anticardiolipin and antiβ2glycoprotein I antibodies measured with various analytical platforms: communication from the ISTH SSC subcommittee on Lupus Anticoagulant/Antiphospholipid antibodies

Background Antiβ2glycoprotein I (aβ2GPI) and anticardiolipin (aCL) IgG/IgM show differences in positive/negative agreement and titers between solid phase platforms. Method specific semiquantitative categorization of titers could improve and harmonize the interpretation across platforms. Aim To evaluate the traditionally 40/80 units thresholds used for aCL and aβ2GPI for categorization into moderate/high positivity with different analytical systems, and to compare with alternative thresholds. Material and methods aCL and aβ2GPI thresholds were calculated for two automated systems (chemiluminescent immunoassay (CLIA) and multiplex flow immunoassay (MFI)) by ROC-curve analysis on 1108 patient samples, including patients with and without APS, and confirmed on a second population (n=279). Alternatively, regression analysis on diluted standard material was applied to identify thresholds. Thresholds were compared to 40/80 threshold measured by an enzyme linked immunosorbent assay (ELISA). Additionally, likelihood ratios (LR) were calculated. Results Threshold levels of 40/80 units show poor agreement between ELISA and automated platforms for classification into low/moderate/high positivity, especially for aCL/aβ2GPI IgG. Agreement for semiquantitative interpretation of aPL IgG between ELISA and CLIA/MFI improves with alternative thresholds. LR for aPL IgG increase for thrombotic and obstetric APS based on 40/80 thresholds for ELISA and adapted thresholds for the other systems, but not for IgM. Conclusion Use of 40/80 units as medium/high thresholds is acceptable for aCL/aβ2GPI IgG ELISA, but not for CLIA and MFI. Alternative semiquantitative thresholds for non-ELISA platforms can be determined by a clinical approach or by using monoclonal antibodies. Semiquantitative reporting of aPL IgM has less impact on increasing probability for APS