270 research outputs found
Anålisis morfológico y molecular de los blenios de agua dulce: una nueva especie del género Salaria ForsskÄl, 1775 (Actinopterygii, Blennidae) en Marruecos.
The North African freshwater fish fauna is scarce compared to other regions of the world, probably due to historical and climatic factors. The western part of North Africa is more diverse than central or eastern areas. Populations of freshwater blennids that have been traditionally ascribed to the species Salaria fluviatilis nowadays inhabit the Sebou basin in Morocco. In this study we demonstrated morphologically and molecularly that these Moroccan populations constitute a new species, for which we provide a formal description. The following diagnostic characters distinguish the newly described species from other freshwater blennids: head without diagonal rows of dark dots or blotches on cheeks; supra-ocular tentacle thick and simple (not branched); 13-15 teeth on the upper jaw and 14-16 on the lower jaw; 16-17 soft anal fin rays; short pre-orbital distance (cephalic index: 2.9-3.8); height of the anterior (spiny) part of the dorsal fin short (dorsal fin index: 0.8-1.3) and 34 vertebrae. Mitochondrial and nuclear genetic distances between the new Salaria species and either S. economidisi or S. fluviatilis are high, especially in the mitochondrial control region (18%), while these genetic distances range from 2 to 3% when the nuclear S7 marker is compared. These morphological and molecular characters differentiate the new species from the remaining freshwater species of the genus (Salaria economidisi and S. fluviatilis). The new species is confined to a small restricted area of the Sebou basin in Morocco and should be considered endangered (EN) according to the IUCN Red List.La fauna de peces de agua dulce del norte de Ăfrica es escasa comparada con otras regiones del mundo debido fundamentalmente a factores histĂłricos y climĂĄticos. El oeste del norte de Ăfrica es mĂĄs diverso que las regiones del centro y del este. En la cuenca del rĂo Sebou habitan actualmente poblaciones de blenios de agua dulce que han sido tradicionalmente adscritas a la especie Salaria fluviatilis. En este estudio demostramos morfolĂłgica y molecularmente que estas poblaciones marroquĂes constituyen una nueva especie, para la cual proveemos una descripciĂłn formal. Los siguientes caracteres diagnĂłsticos distinguen a la nueva especie descrita del resto de especies de blenios de agua dulce: cabeza sin una fila diagonal de puntos oscuros o manchas en las mejillas; tentĂĄculo supraocular grueso y simple (no ramificado); 13-15 dientes en la mandĂbula superior y 14-16 en la inferior; 16-17 radios blandos en la aleta anal; distancia preorbital corta (Ăndice cefĂĄlico: 2.9-3.8); altura de la region anterior de la aleta dorsal corta (Ăndice dorsal: 0.8-1.3) y 34 vĂ©rtebras. Las distancias genĂ©ticas mitocondriales y nuclear entre la nueva especie de Salaria y las otras dos especies son altas, especialmente en la regiĂłn control (18%), mientras que estas distancias genĂ©ticas variaron entre 2-3% para el gen nuclear S7. Estos caracteres morfolĂłgicos y moleculares diferencian a la nueva especie del resto de blenios de agua dulce del gĂ©nero (Salaria fluviatilis y S. economidisi). La nueva especie estĂĄ confinada a la cuenca del rĂo Sebou en Marruecos y deberĂa ser considerada como En Peligro (EN) de acuerdo a las categorĂas de la lista roja
A novel scalable representative-based forecasting approach of service quality
© 2020, Springer-Verlag GmbH Austria, part of Springer Nature. Several approaches to forecast the service quality based on its quality of service (QoS) properties are reported in the literature. However, their main disadvantage resides in their limited scalability. In fact, they elaborate a forecasting model for each quality attribute per service, which cannot scale well for large or even medium size datasets of services. Accordingly, we propose a novel scalable representative-based forecasting approach of QoS. The QoS is modeled as a multivariate time series in which the values of service attributes are evaluated at each time instant and forecasted based on three stages. First, a data aggregation function is applied to the multivariate time series data. Then, principal component analysis (PCA) is applied to the quality attributes to determine the most relevant ones. The reduced data is then clustered, so that, a representative for each cluster is computed. Finally, a forecasting model is built for each cluster representative for the sake of deriving other servicesâ forecasting models. A set of extensive experiments are carried out to assess the efficiency and accuracy of the proposed approach on a dataset of real services. The experimental results show that the proposed approach is up to 75% more efficient than direct forecasting approaches using time measurements while increasing the number of forecasted services and that the elaborated forecasting models enjoy insignificant forecasting errors
Pathotypic diversity of Rhynchosporium secalis (Oudem) in Tunisia
Scald, caused by Rhynchosporium secalis (Oudem), is an important disease of barley in Tunisia particularly in northern, northwestern and central parts of the country where the climate is usually cold and wet during most of the barley growing season. Pathogenic variability of the barley scald pathogen in Tunisia was determined by testing the pathogenicity of 100 isolates from 5 different regions on 19 host differentials. Pathotypic diversity was high, with 93 R. secalis pathotypes identified on two differential sets (one comprising 9 and the other 10 barley lines) containing known resistance genes. A few pathotypes comprised 2% of the isolates; however, the majorities were represented by a single isolate. None of the differential lines was resistant to all isolates. The differential cultivar âAstrixâ was the least compatible with the scald pathotypes followed by the differential cultivars âAtlasâ and âAbyssiniaâ. Compatibility of the pathotypes on âRihaneâ (69%) was close to that on âOsirisâ (73%) and âLa Mesitaâ (61%). None of the pathotypes was found in all the five regions of Tunisia surveyed. Some pathotypes were specific to a single region while others were found in several regions. The incidence of pathotypes varied considerably among regions, with region 3 (northwestern Tunisia) comprising the largest number of pathotypes. Virulent pathotypes were recovered in all regions but more pathotypic variability (44%) was observed in the semi-arid region 3. Differential cultivars allowed classification of R. secalis in four virulence groups. Canonical discriminant analysis showed no apparent association between virulence and geographical origin of the populations. Pathogenic variability in R. secalis in Tunisia was found not to be associated with geographical region, hence, the necessity for deployment of different resistance sources in major barley growing areas.Key words: Rhynchosporium secalis, barley, virulence groups, pathotypic variation
Accident vasculaire cerebral ischemique post-chimiotherapie pour cancer du sein
IntroductionLa chimiothĂ©rapie anticancĂ©reuse est pourvoyeuse dâun large spectre de complications neurologiques. Parmi ces complications les accidents vasculaires cĂ©rĂ©braux ischĂ©miques (AVCI) restent un Ă©vĂšnement inhabituel dont lâincidence est de 0,14%.ObjectifRapporter et commenter lâobservation dâune patiente ayant prĂ©sentĂ© un AVCI dans les suites dâune chimiothĂ©rapie pour cancer du sein.ObservationPatiente ĂągĂ©e de 46ans, traitĂ©e pour une Ă©pilepsie gĂ©nĂ©ralisĂ©e, et sans facteur de risque cardiovasculaire, est suivie pour un cancer du sein. Elle a prĂ©sentĂ© au dĂ©cours de la chimiothĂ©rapie un accident vasculaire cĂ©rĂ©bral ischĂ©mique sylvien droit confirmĂ© au scanner cĂ©rĂ©bral. Les explorations cardiaques sont normales, ainsi que le bilan biologique Ă©tiologique.DiscussionLe diagnostic dâAVC post-chimiothĂ©rapie a Ă©tĂ© retenu chez notre patiente sur la base de lâabsence de facteur de risque vasculaire et la nĂ©gativitĂ© du bilan Ă©tiologique, ainsi que lâusage du 5 Fluorouracile qui a Ă©tĂ© incriminĂ© dans la survenue dâAVC ischĂ©miques. La survenue de cette complication dĂ©pend du type de drogue utilisĂ©, et de certaines associations thĂ©rapeutiques, et relĂšverait de plusieurs mĂ©canismes pouvant ĂȘtre intriquĂ©s. Le bilan doit ĂȘtre le plus complet possible afin dâaffirmer lâimputabilitĂ© de la chimiothĂ©rapie.ConclusionNotre observation souligne la sĂ©vĂ©ritĂ© des complications neurologiques de la chimiothĂ©rapie, ainsi que le dilemme thĂ©rapeutique posĂ©, en lâabsence de protocole de prise en charge codifiĂ©.Mots clĂ©s : Accident vasculaire cĂ©rĂ©bral, cancer du sein, chimiothĂ©rapie, toxicitĂ©, 5-Fluorouracil
Improved flux limits for neutrinos with energies above 10 eV from observations with the Westerbork Synthesis Radio Telescope
Particle cascades initiated by ultra-high energy (UHE) neutrinos in the lunar
regolith will emit an electromagnetic pulse with a time duration of the order
of nano seconds through a process known as the Askaryan effect. It has been
shown that in an observing window around 150 MHz there is a maximum chance for
detecting this radiation with radio telescopes commonly used in astronomy. In
50 hours of observation time with the Westerbork Synthesis Radio Telescope
array we have set a new limit on the flux of neutrinos, summed over all
flavors, with energies in excess of eV.Comment: Submitted to Phys. Rev. Let
Two highly divergent alcohol dehydrogenases of melon exhibit fruit ripening-specific expression and distinct biochemical characteristics
Alcohol dehydrogenases (ADH) participate in
the biosynthetic pathway of aroma volatiles in fruit by
interconverting aldehydes to alcohols and providing substrates
for the formation of esters. Two highly divergent
ADH genes (15% identity at the amino acid level) of
Cantaloupe Charentais melon (Cucumis melo var. Cantalupensis)
have been isolated. Cm-ADH1 belongs to the
medium-chain zinc-binding type of ADHs and is highly
similar to all ADH genes expressed in fruit isolated so far.
Cm-ADH2 belongs to the short-chain type of ADHs. The
two encoded proteins are enzymatically active upon
expression in yeast. Cm-ADH1 has strong preference for
NAPDH as a co-factor, whereas Cm-ADH2 preferentially
uses NADH. Both Cm-ADH proteins are much more active
as reductases with Kms 10â20 times lower for the conversion
of aldehydes to alcohols than for the dehydrogenation
of alcohols to aldehydes. They both show strong preference
for aliphatic aldehydes but Cm-ADH1 is capable of
reducing branched aldehydes such as 3-methylbutyraldehyde,
whereas Cm-ADH2 cannot. Both Cm-ADH genes are
expressed specifically in fruit and up-regulated during
ripening. Gene expression as well as total ADH activity are
strongly inhibited in antisense ACC oxidase melons and in
melon fruit treated with the ethylene antagonist 1-methylcyclopropene
(1-MCP), indicating a positive regulation by
ethylene. These data suggest that each of the Cm-ADH
protein plays a specific role in the regulation of aroma
biosynthesis in melon fruit
Experimental and modeling study of the autoignition of 1-hexene/iso-octane mixtures at low temperatures
Autoignition delay times have been measured in a rapid compression machine at
Lille at temperatures after compression from 630 to 840 K, pressures from 8 to
14 bar, \Phi = 1 and for a iso octane/1 hexene mixture containing 82%
iso-octane and 18% 1 hexene. Results have shown that this mixture is strongly
more reactive than pure iso-octane, but less reactive than pure 1 hexene. It
exhibits a classical low temperature behaviour, with the appearance of cool
flame and a negative temperature coefficient region. The composition of the
reactive mixture obtained after the cool flame has also been determined. A
detailed kinetic model has been obtained by using the system EXGAS, developed
in Nancy for the automatic generation of kinetic mechanisms, and an acceptable
agreement with the experimental results has been obtained both for autoignition
delay times and for the distribution of products. A flow rate analysis reveals
that the crossed reactions between species coming from both reactants (like
H-abstractions or combinations) are negligible in the main flow consumption of
the studied hydrocarbons. The ways of formation of the main primary products
observed and the most sensitive rate constants have been identified
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