51 research outputs found
L'instrumentation des activités publiques. Le cas d'une université
Les universités françaises doivent faire face à de nouvelles contraintes budgétaires et financiÚres qui induisent l'introduction de nouveaux outils de management. L'objectif de la recherche est d'explorer le rÎle joué par les représentations sociales des acteurs dans l'émergence d'un outil de gestion en sollicitant une grille de lecture institutionnelle de l'environnement. La méthodologie est fondée sur une recherche action d'un an au sein d'une université ayant permis d'étudier les attentes des acteurs face à l'émergence d'un outil de comptabilité de gestion. Il en ressort une multiplicité des représentations qui bloque l'émergence d'un outil adapté et amplifie la distance entre les acteurs et l'institution soulignant ainsi la force de pression de l'environnement institutionnel sur les représentations sociales.représentations sociales ; environnement institutionnel ; new public management ; émergence d'un outil de gestion
The lack of star formation gradients in galaxy groups up to z~1.6
In the local Universe, galaxy properties show a strong dependence on
environment. In cluster cores, early type galaxies dominate, whereas
star-forming galaxies are more and more common in the outskirts. At higher
redshifts and in somewhat less dense environments (e.g. galaxy groups), the
situation is less clear. One open issue is that of whether and how the star
formation rate (SFR) of galaxies in groups depends on the distance from the
centre of mass. To shed light on this topic, we have built a sample of X-ray
selected galaxy groups at 0<z<1.6 in various blank fields (ECDFS, COSMOS,
GOODS). We use a sample of spectroscopically confirmed group members with
stellar mass M >10^10.3 M_sun in order to have a high spectroscopic
completeness. As we use only spectroscopic redshifts, our results are not
affected by uncertainties due to projection effects. We use several SFR
indicators to link the star formation (SF) activity to the galaxy environment.
Taking advantage of the extremely deep mid-infrared Spitzer MIPS and
far-infrared Herschel PACS observations, we have an accurate, broad-band
measure of the SFR for the bulk of the star-forming galaxies. We use
multi-wavelength SED fitting techniques to estimate the stellar masses of all
objects and the SFR of the MIPS and PACS undetected galaxies. We analyse the
dependence of the SF activity, stellar mass and specific SFR on the
group-centric distance, up to z~1.6, for the first time. We do not find any
correlation between the mean SFR and group-centric distance at any redshift. We
do not observe any strong mass segregation either, in agreement with
predictions from simulations. Our results suggest that either groups have a
much smaller spread in accretion times with respect to the clusters and that
the relaxation time is longer than the group crossing time.Comment: Accepted for publication in MNRA
Integration of palliative and supportive care in the management of advanced liver disease:development and evaluation of a prognostic screening tool and supportive care intervention
BACKGROUND AND OBJECTIVES: Patients with decompensated cirrhosis rarely receive palliative and supportive care interventions, which are routine in other life-limiting diseases. We aimed to design and evaluate a prognostic screening tool to routinely identify inpatients with decompensated cirrhosis at high risk of dying over the coming year, alongside the development of a supportive care intervention. DESIGN: Clinical notes from consecutive patients admitted as an emergency to University Hospitals Bristol with a diagnosis of cirrhosis over two distinct 90-day periods were scrutinised retrospectively for the presence or absence of five evidence-based factors associated with poor prognosis. These were analysed against their ability to predict mortality at 1â
year. âPlan-Do-Study-Actâ (PDSA) methodology was used to incorporate poor-prognosis screening into the routine assessment of patients admitted with cirrhosis, and develop a supportive care intervention. RESULTS: 73 admissions were scrutinised (79.5% male, 63% alcohol-related liver disease, median age 54). The presence of three or more poor-prognosis criteria at admission predicted 1-year mortality with sensitivity, specificity and positive predictive value of 72.2%, 83.8% and 81.3%, respectively, and was used as a trigger for implementing the supportive care intervention. Following modification from six PDSA cycles, prognostic screening was integrated into the assessment of all patients admitted with decompensated cirrhosis, with the supportive care intervention (developed simultaneously) instigated for appropriate patients. CONCLUSIONS: We describe a model of care which identifies inpatients with cirrhosis at significant risk of dying over the coming year, and describe development of a supportive care intervention, which can be offered to suitable patients in parallel to ongoing active management
On Star Formation Rates and Star Formation Histories of Galaxies out to z ~ 3
We compare multi-wavelength SFR indicators out to z~3 in GOODS-South. Our
analysis uniquely combines U-to-8um photometry from FIREWORKS, MIPS 24um and
PACS 70, 100, and 160um photometry from the PEP survey, and Ha spectroscopy
from the SINS survey. We describe a set of conversions that lead to a
continuity across SFR indicators. A luminosity-independent conversion from 24um
to total infrared luminosity yields estimates of LIR that are in the median
consistent with the LIR derived from PACS photometry, albeit with significant
scatter. Dust correction methods perform well at low to intermediate levels of
star formation. They fail to recover the total amount of star formation in
systems with large SFR_IR/SFR_UV ratios, typically occuring at the highest SFRs
(SFR_UV+IR \gtrsim 100 Msun/yr) and redshifts (z \gtrsim 2.5) probed. Finally,
we confirm that Ha-based SFRs at 1.5<z<2.6 are consistent with SFR_SED and
SFR_UV+IR provided extra attenuation towards HII regions is taken into account
(Av,neb = Av,continuum / 0.44). With the cross-calibrated SFR indicators in
hand, we perform a consistency check on the star formation histories inferred
from SED modeling. We compare the observed SFR-M relations and mass functions
at a range of redshifts to equivalents that are computed by evolving lower
redshift galaxies backwards in time. We find evidence for underestimated
stellar ages when no stringent constraints on formation epoch are applied. We
demonstrate how resolved SED modeling, or alternatively deep UV data, may help
to overcome this bias. The age bias is most severe for galaxies with young
stellar populations, and reduces towards older systems. Finally, our analysis
suggests that SFHs typically vary on timescales that are long (at least several
100 Myr) compared to the galaxies' dynamical time.Comment: Accepted for publication in The Astrophysical Journal, 19 pages, 15
figure
Hi-GAL, theHerschelinfrared Galactic Plane Survey: photometric maps and compact source catalogues
Aims. We present the first public release of high-quality data products (DR1) from Hi-GAL, the Herschel infrared Galactic Plane Survey. Hi-GAL is the keystone of a suite of continuum Galactic plane surveys from the near-IR to the radio and covers five wavebands at 70, 160, 250, 350 and 500 ”m, encompassing the peak of the spectral energy distribution of cold dust for 8 < T < 50 K. This first Hi-GAL data release covers the inner
Milky Way in the longitude range 68⊠> t > â70⊠in a |b| †1⊠latitude strip. ⌠âŒ
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Methods. Photometric maps have been produced with the ROMAGAL pipeline, which optimally capitalizes on the excellent sensitivity and
stability of the bolometer arrays of the Herschel PACS and SPIRE photometric cameras. It delivers images of exquisite quality and dynamical range, absolutely calibrated with Planck and IRAS, and recovers extended emission at all wavelengths and all spatial scales, from the point-spread function to the size of an entire 2⊠à 2⊠âtileâ that is the unit observing block of the survey. The compact source catalogues were generated with the CuTEx algorithm, which was specifically developed to optimise source detection and extraction in the extreme conditions of intense and spatially varying background that are found in the Galactic plane in the thermal infrared.
Results. Hi-GAL DR1 images are cirrus noise limited and reach the 1Ï-rms predicted by the Herschel Time Estimators for parallel-mode obser- vations at 6011 sâ1 scanning speed in relatively low cirrus emission regions. Hi-GAL DR1 images will be accessible through a dedicated web-based image cutout service. The DR1 Compact Source Catalogues are delivered as single-band photometric lists containing, in addition to source posi- tion, peak, and integrated flux and source sizes, a variety of parameters useful to assess the quality and reliability of the extracted sources. Caveats and hints to help in this assessment are provided. Flux completeness limits in all bands are determined from extensive synthetic source experiments and greatly depend on the specific line of sight along the Galactic plane because the background strongly varies as a function of Galactic longitude. Hi-GAL DR1 catalogues contain 123210, 308509, 280685, 160972, and 85460 compact sources in the five bands
microbeMASST: A Taxonomically-informed Mass Spectrometry Search Tool for Microbial Metabolomics Data
microbeMASST, a taxonomically informed mass spectrometry (MS) search tool, tackles limited microbial metabolite annotation in untargeted metabolomics experiments. Leveraging a curated database of >60,000 microbial monocultures, users can search known and unknown MS/MS spectra and link them to their respective microbial producers via MS/MS fragmentation patterns. Identification of microbe-derived metabolites and relative producers without a priori knowledge will vastly enhance the understanding of microorganismsâ role in ecology and human health
RÎle des connexines 43 astrocytaires : une étude fonctionnelle dans un modÚle murin de dépression basé sur le stress chronique
Glial cells including astrocytes - as much abundant as neurons in the brain - may play an important role in anxiety, depression and possibly antidepressant drugs response. Previous studies in humans and animals are consistent with this hypothesis since they report an association between changes in astroglial markers expression and the severity of psychiatric disorders. Among those markers, the connexnis-43 (Cx43) are particularly interesting. Those transmembrane proteins are involved in the formation of two functional units of communications: the gap-junctions (GJs) which facilitate the communication between two neighboring astrocytes, and the hemichannels (HCs) which are able to release neuroactive molecules (gliotransmitters i.e. glutamate, ATP, D-serine) in the synaptic cleft. Decreased levels of Cx43 were unveiled in different brain regions of depressed patients but also in relevant mouse models of depression. Functionally, the induction of an anxio/depressive-like phenotype has been associated with a decreased activity of GJ and an increased HC activity. In light of these data, the aim of this thesis was to better characterize the role of Cx43 in anxio/depressive-like behaviors and antidepressant drugs response using genetic and pharmacological approaches. Our results show that hippocampal genetic inactivation of Cx43 has no effect on neuro-behaviors. However, in a mouse model of depression based on chronic corticosterone treatment exposure (CORT model), the genetic inactivation of Cx43 induces anxiolytic-/antidepressant-like effects. Mechanistically, these behavioral responses would be linked to an attenuation of hippocampal glutamate release through HCs and a lower hypothalamic pituitary adrenal (HPA) axis reactivity. Regarding the pharmacological approach, our work provides experimental evidence that systemic administration of the connexins blocker carbenoxolone, enhances the acute effects of a serotonin reuptake inhibitor in basal conditions while hindering its chronic beneficial effects in a mouse model of depression. Together, those results suggest the importance of the cellular microenvironment in the way Cx43 may influence treatment response. This work points out the importance of astroglial Cx43 in mood through the modulation of neuronal network associated with HPA. It also emphasizes the importance to develop Cx43 modulators to strengthen the therapeutic activity of antidepressant drugs. Further studies are warranted to define the modalities of such innovative strategies combining pharmacological agents with astroglial and neuronal tropisms.Les cellules gliales dont les astrocytes - au moins aussi nombreux que les neurones dans le cerveau - joueraient un rĂŽle important dans l'anxiĂ©tĂ©, la dĂ©pression et probablement dans la rĂ©ponse aux antidĂ©presseurs. Plusieurs Ă©tudes menĂ©es chez l'Homme et l'animal vont dans ce sens puisqu'elles mettent en Ă©vidence une association entre des changements d'expression de diffĂ©rents marqueurs astrocytaires et la sĂ©vĂ©ritĂ© de ces troubles psychiatriques. C'est notamment le cas de la connexine 43 (Cx43), une protĂ©ine transmembranaire impliquĂ©e dans la formation de deux unitĂ©s fonctionnelles distinctes : les jonctions communicantes (JCs) qui assurent la communication entre deux astrocytes voisins et les hĂ©micanaux (HCs) dont le rĂŽle est de libĂ©rer de molĂ©cules neuro-actives (gliotransmetteurs i.e. glutamate, ATP, D-sĂ©rine) dans la fente synaptique. En effet, une diminution de l'expression des Cx43 a Ă©tĂ© rapportĂ©e dans diffĂ©rentes rĂ©gions cĂ©rĂ©brales de patients dĂ©pressifs et dans des modĂšles murins de dĂ©pression. En revanche, d'un point de vue fonctionnel, l'induction d'un phĂ©notype "anxio-dĂ©pressif" serait associĂ©e Ă une diminution de l'activitĂ© des JCs et Ă une augmentation de l'activitĂ© des HCs. Face Ă ces effets opposĂ©s, l'objectif de cette thĂšse Ă©tait de caractĂ©riser plus finement le rĂŽle des Cx43 dans les comportements "anxio-dĂ©pressifs" et la rĂ©ponse aux psychotropes en utilisant des approches d'inactivation gĂ©nĂ©tiques et pharmacologiques de ces protĂ©ines. Nos rĂ©sultats montrent que l'inactivation gĂ©nĂ©tique des Cx43 dans l'hippocampe n'entraine aucun effet neuro-comportemental. En revanche, dans un modĂšle de dĂ©pression basĂ© sur l'exposition chronique des souris Ă la corticostĂ©rone (modĂšle CORT), l'inactivation gĂ©nĂ©tique des Cx43 exerce des effets de type anxiolytiques-antidĂ©presseurs. D'un point de vue mĂ©canistique, ces effets seraient liĂ©s Ă une diminution de la libĂ©ration hippocampique de glutamate par les HCs et Ă une attĂ©nuation de la rĂ©activitĂ© de l'axe hypothalamo-hypophysaire (HPA). Concernant l'inactivation pharmacologique des Cx43, nos travaux apportent des Ă©vidences expĂ©rimentales sur le fait que l'administration systĂ©mique de carbenoxolone, un bloqueur des connexines, potentialise la rĂ©ponse aiguĂ« d'un inhibiteur de recapture de la sĂ©rotonine en conditions basales, mais s'oppose Ă ses effets bĂ©nĂ©fiques chroniques dans un modĂšle de dĂ©pression. Le microenvironnement cellulaire semble donc essentiel dans la maniĂšre dont les Cx43 influencent la rĂ©ponse aux antidĂ©presseurs. L'ensemble de ces rĂ©sultats de thĂšse laissent entrevoir un rĂŽle des Cx43 astrocytaires dans la rĂ©gulation de l'humeur via la modulation de circuits neuronaux convergeant vers l'axe HPA. Ils soulignent Ă©galement l'intĂ©rĂȘt de moduler les Cx43 pour renforcer l'activitĂ© thĂ©rapeutiques des antidĂ©presseurs actuellement disponibles. Les futures recherches devront prĂ©ciser les modalitĂ©s de ces nouvelles stratĂ©gies combinant des agents pharmacologiques Ă tropisme astrocytaire et neuronal
Role of astroglial connexin 43 : a functional study in a mouse model of depression base on chronic stress
Les cellules gliales dont les astrocytes - au moins aussi nombreux que les neurones dans le cerveau - joueraient un rĂŽle important dans l'anxiĂ©tĂ©, la dĂ©pression et probablement dans la rĂ©ponse aux antidĂ©presseurs. Plusieurs Ă©tudes menĂ©es chez l'Homme et l'animal vont dans ce sens puisqu'elles mettent en Ă©vidence une association entre des changements d'expression de diffĂ©rents marqueurs astrocytaires et la sĂ©vĂ©ritĂ© de ces troubles psychiatriques. C'est notamment le cas de la connexine 43 (Cx43), une protĂ©ine transmembranaire impliquĂ©e dans la formation de deux unitĂ©s fonctionnelles distinctes : les jonctions communicantes (JCs) qui assurent la communication entre deux astrocytes voisins et les hĂ©micanaux (HCs) dont le rĂŽle est de libĂ©rer de molĂ©cules neuro-actives (gliotransmetteurs i.e. glutamate, ATP, D-sĂ©rine) dans la fente synaptique. En effet, une diminution de l'expression des Cx43 a Ă©tĂ© rapportĂ©e dans diffĂ©rentes rĂ©gions cĂ©rĂ©brales de patients dĂ©pressifs et dans des modĂšles murins de dĂ©pression. En revanche, d'un point de vue fonctionnel, l'induction d'un phĂ©notype "anxio-dĂ©pressif" serait associĂ©e Ă une diminution de l'activitĂ© des JCs et Ă une augmentation de l'activitĂ© des HCs. Face Ă ces effets opposĂ©s, l'objectif de cette thĂšse Ă©tait de caractĂ©riser plus finement le rĂŽle des Cx43 dans les comportements "anxio-dĂ©pressifs" et la rĂ©ponse aux psychotropes en utilisant des approches d'inactivation gĂ©nĂ©tiques et pharmacologiques de ces protĂ©ines. Nos rĂ©sultats montrent que l'inactivation gĂ©nĂ©tique des Cx43 dans l'hippocampe n'entraine aucun effet neuro-comportemental. En revanche, dans un modĂšle de dĂ©pression basĂ© sur l'exposition chronique des souris Ă la corticostĂ©rone (modĂšle CORT), l'inactivation gĂ©nĂ©tique des Cx43 exerce des effets de type anxiolytiques-antidĂ©presseurs. D'un point de vue mĂ©canistique, ces effets seraient liĂ©s Ă une diminution de la libĂ©ration hippocampique de glutamate par les HCs et Ă une attĂ©nuation de la rĂ©activitĂ© de l'axe hypothalamo-hypophysaire (HPA). Concernant l'inactivation pharmacologique des Cx43, nos travaux apportent des Ă©vidences expĂ©rimentales sur le fait que l'administration systĂ©mique de carbenoxolone, un bloqueur des connexines, potentialise la rĂ©ponse aiguĂ« d'un inhibiteur de recapture de la sĂ©rotonine en conditions basales, mais s'oppose Ă ses effets bĂ©nĂ©fiques chroniques dans un modĂšle de dĂ©pression. Le microenvironnement cellulaire semble donc essentiel dans la maniĂšre dont les Cx43 influencent la rĂ©ponse aux antidĂ©presseurs. L'ensemble de ces rĂ©sultats de thĂšse laissent entrevoir un rĂŽle des Cx43 astrocytaires dans la rĂ©gulation de l'humeur via la modulation de circuits neuronaux convergeant vers l'axe HPA. Ils soulignent Ă©galement l'intĂ©rĂȘt de moduler les Cx43 pour renforcer l'activitĂ© thĂ©rapeutiques des antidĂ©presseurs actuellement disponibles. Les futures recherches devront prĂ©ciser les modalitĂ©s de ces nouvelles stratĂ©gies combinant des agents pharmacologiques Ă tropisme astrocytaire et neuronal.Glial cells including astrocytes - as much abundant as neurons in the brain - may play an important role in anxiety, depression and possibly antidepressant drugs response. Previous studies in humans and animals are consistent with this hypothesis since they report an association between changes in astroglial markers expression and the severity of psychiatric disorders. Among those markers, the connexnis-43 (Cx43) are particularly interesting. Those transmembrane proteins are involved in the formation of two functional units of communications: the gap-junctions (GJs) which facilitate the communication between two neighboring astrocytes, and the hemichannels (HCs) which are able to release neuroactive molecules (gliotransmitters i.e. glutamate, ATP, D-serine) in the synaptic cleft. Decreased levels of Cx43 were unveiled in different brain regions of depressed patients but also in relevant mouse models of depression. Functionally, the induction of an anxio/depressive-like phenotype has been associated with a decreased activity of GJ and an increased HC activity. In light of these data, the aim of this thesis was to better characterize the role of Cx43 in anxio/depressive-like behaviors and antidepressant drugs response using genetic and pharmacological approaches. Our results show that hippocampal genetic inactivation of Cx43 has no effect on neuro-behaviors. However, in a mouse model of depression based on chronic corticosterone treatment exposure (CORT model), the genetic inactivation of Cx43 induces anxiolytic-/antidepressant-like effects. Mechanistically, these behavioral responses would be linked to an attenuation of hippocampal glutamate release through HCs and a lower hypothalamic pituitary adrenal (HPA) axis reactivity. Regarding the pharmacological approach, our work provides experimental evidence that systemic administration of the connexins blocker carbenoxolone, enhances the acute effects of a serotonin reuptake inhibitor in basal conditions while hindering its chronic beneficial effects in a mouse model of depression. Together, those results suggest the importance of the cellular microenvironment in the way Cx43 may influence treatment response. This work points out the importance of astroglial Cx43 in mood through the modulation of neuronal network associated with HPA. It also emphasizes the importance to develop Cx43 modulators to strengthen the therapeutic activity of antidepressant drugs. Further studies are warranted to define the modalities of such innovative strategies combining pharmacological agents with astroglial and neuronal tropisms
RĂŽle des connexines astrocytaires dans la rĂ©gulation des taux extracellulaires de glutamateâ: implication pour le traitement des Ă©pisodes dĂ©pressifs majeurs
La dĂ©pression majeure est une pathologie psychiatrique reposant sur diffĂ©rents mĂ©canismes neurobiologiques. Parmi ces mĂ©canismes, on trouve une hypersensibilitĂ© de lâaxe hypothalamo-hypophyso-surrĂ©nalien associĂ©e Ă un excĂšs de cortisol dans le sang et un dĂ©ficit de neurotransmission monoaminergique. Ainsi, lâefficacitĂ© thĂ©rapeutique des antidĂ©presseurs actuels repose sur leur capacitĂ© Ă augmenter les taux extracellulaires de monoamines dans la fente synaptique. Depuis la dĂ©couverte des effets antidĂ©presseurs rapides et durables de la kĂ©tamine, un antagoniste des rĂ©cepteurs NMDA, un intĂ©rĂȘt croissant est portĂ© sur les moyens pharmacologiques attĂ©nuant lâaction du glutamate pour traiter la dĂ©pression majeure. Les astrocytes jouent un rĂŽle prĂ©pondĂ©rant dans la balance excitation/inhibition du systĂšme nerveux central en rĂ©gulant la recapture et la sĂ©crĂ©tion du glutamate. De maniĂšre intĂ©ressante, la libĂ©ration de cet acide aminĂ© excitateur est contrĂŽlĂ©e, du moins en partie, par des canaux membranaires regroupĂ©s au niveau de jonctions intercellulaires de type «âgapâ»âou dâhĂ©micanaux formĂ©s par les connexines 30 et 43. Les donnĂ©es prĂ©cliniques suggĂšrent que ces deux entitĂ©s fonctionnelles ont des effets sur les comportements Ă©motionnels dans diffĂ©rents modĂšles murins de dĂ©pression. AprĂšs un bref rappel sur les troubles de lâhumeur et leurs traitements, cette revue de la littĂ©rature dĂ©crit le rĂŽle des astrocytes et des connexines dans la neurotransmission glutamatergique et la dĂ©pression majeure. Les arguments avancĂ©s soulignent lâintĂ©rĂȘt thĂ©rapeutique potentiel du blocage des connexines astrocytaires mais aussi les difficultĂ©s pratiques Ă cibler la fonction hĂ©micanal sans impacter la fonction «âgapâ»
Construire un outil de comptabilité de gestion au sein d'une université. Retour sur un acte manqué
International audienceLes universitĂ©s font face Ă de nouvelles contraintes financiĂšres qui se traduisent par lâintroduction de nouveaux outils de management. Lâobjectif de la recherche est dâexplorer le rĂŽle jouĂ© par les reprĂ©sentations sociales des acteurs dans lâĂ©mergence dâun outil de gestion, grĂące Ă une Ă©tude de cas par observation participante dâun an au sein dâune universitĂ©. Il en ressort une multiplicitĂ© des reprĂ©sentations sociales et la nĂ©cessitĂ© dâengager un pilotage actif de ces reprĂ©sentations
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