195 research outputs found
Rotating models of young solar-type stars : Exploring braking laws and angular momentum transport processes
We study the predicted rotational evolution of solar-type stars from the
pre-main sequence to the solar age with 1D rotating evolutionary models
including physical ingredients. We computed rotating evolution models of
solar-type stars including an external stellar wind torque and internal
transport of angular momentum following the method of Maeder and Zahn with the
code STAREVOL. We explored different formalisms and prescriptions available
from the literature. We tested the predictions of the models against recent
rotational period data from extensive photometric surveys, lithium abundances
of solar-mass stars in young clusters, and the helioseismic rotation profile of
the Sun. We find a best-matching combination of prescriptions for both internal
transport and surface extraction of angular momentum. This combination provides
a very good fit to the observed evolution of rotational periods for solar-type
stars from early evolution to the age of the Sun. Additionally, we show that
fast rotators experience a stronger coupling between their radiative region and
the convective envelope. Regardless of the set of prescriptions, however, we
cannot simultaneously reproduce surface angular velocity and the internal
profile of the Sun or the evolution of lithium abundance. We confirm the idea
that additional transport mechanisms must occur in solar-type stars until they
reach the age of the Sun. Whether these processes are the same as those needed
to explain recent asteroseismic data in more advanced evolutionary phases is
still an open question.Comment: 16 pages, 16 figures, accepted for publication in A&
Transfusion practices in postpartum hemorrhage: a population-based study.: Transfusion in Postpartum Haemorrhage
International audienceOBJECTIVE: To describe transfusion practices and anemia in women with postpartum hemorrhage (PPH), according to the clinical context. DESIGN: Population-based cohort study. SETTING: A total of 106 French maternity units (146 781 deliveries, December 2004 to November 2006). POPULATION: All women with PPH (n = 9365). METHODS: Description of the rate of red blood cell (RBC) transfusion in PPH overall and compared with transfusion guidelines. MAIN OUTCOME MEASURES: Transfusion practices and postpartum anemia by mode of delivery and cause of PPH in women given RBCs within 12 h after PPH. RESULTS: A total of 701 women received RBCs (0.48 ± 0.04% of all women and 7.5 ± 0.5% of women with PPH). Half the women with clinical PPH and hemoglobin lower than 7.0 g/dL received no RBCs. In the group with clinical PPH and transfusion within 12 h (n = 426), operative vaginal delivery was associated with a larger maximal hemoglobin drop, more frequent administration of fresh-frozen plasma (FFP) and pro-hemostatic agents [odds ratio (OR) 3.54, 95% confidence interval (95% CI) 1.12-11.18], transfusion of larger volumes of RBCs and FFP, a higher rate of massive RBCs transfusion (OR 5.22, 95% CI 2.12-12.82), and more frequent use of conservative surgery (OR 3.2, 95% CI 1.34-7.76), compared with spontaneous vaginal delivery. CONCLUSIONS: The RBC transfusion for PPH was not given in a large proportion of women with very low hemoglobin levels despite guidelines to the contrary. Operative vaginal delivery is characterized by higher blood loss and more transfusions than spontaneous vaginal delivery
Functional diversity and redundancy across fish gut, sediment and water bacterial communities.
This article explores the functional diversity and redundancy in a bacterial metacommunity constituted of three habitats (sediment, water column and fish gut) in a coastal lagoon under anthropogenic pressure. Comprehensive functional gene arrays covering a wide range of ecological processes and stress resistance genes to estimate the functional potential of bacterial communities were used. Then, diversity partitioning was used to characterize functional diversity and redundancy within (α), between (β) and across (γ) habitats. It was showed that all local communities exhibit a highly diversified potential for the realization of key ecological processes and resistance to various environmental conditions, supporting the growing evidence that macro-organisms microbiomes harbour a high functional potential and are integral components of functional gene dynamics in aquatic bacterial metacommunities. Several levels of functional redundancy at different scales of the bacterial metacommunity were observed (within local communities, within habitats and at the metacommunity level). The results suggested a high potential for the realization of spatial ecological insurance within this ecosystem, that is, the functional compensation among microorganisms for the realization and maintenance of key ecological processes, within and across habitats. Finally, the role of macro-organisms as dispersal vectors of microbes and their potential influence on marine metacommunity dynamics were discussed
Multifaceted intervention to decrease the rate of severe postpartum haemorrhage: the PITHAGORE6 cluster-randomised controlled trial.: Intervention to decrease severe postpartum haemorrhage
International audienceOBJECTIVE: Decreasing the prevalence of severe postpartum haemorrhages (PPH) is a major obstetrical challenge. These are often considered to be associated with substandard initial care. Strategies to increase the appropriateness of early management of PPH must be assessed. We tested the hypothesis that a multifaceted intervention aimed at increasing the translation into practice of a protocol for early management of PPH, would reduce the incidence of severe PPH. DESIGN: Cluster-randomised trial. POPULATION: 106 maternity units in six French regions. METHODS: Maternity units were randomly assigned to receive the intervention, or to have the protocol passively disseminated. The intervention combined outreach visits to discuss the protocol in each local context, reminders, and peer reviews of severe incidents, and was implemented in each maternity hospital by a team pairing an obstetrician and a midwife. MAIN OUTCOME MEASURES: The primary outcome was the incidence of severe PPH, defined as a composite of one or more of: transfusion, embolisation, surgical procedure, transfer to intensive care, peripartum haemoglobin decrease of 4 g/dl or more, death. The main secondary outcomes were PPH management practices. RESULTS: The mean rate of severe PPH was 1.64% (SD 0.80) in the intervention units and 1.65% (SD 0.96) in control units; difference not significant. Some elements of PPH management were applied more frequently in intervention units-help from senior staff (P = 0.005), or tended to - second-line pharmacological treatment (P = 0.06), timely blood test (P = 0.09). CONCLUSION: This educational intervention did not affect the rate of severe PPH as compared with control units, although it improved some practices
Congenital and Disseminated Pyogenic Granuloma-like Vascular Lesions
International audienceWe report an exceptional case of multiple cutaneous and visceral neonatal pyogenic granuloma (PG) initially suggestive of a diffuse neonatal haemangiomatosis. CASE REPORT A full-term female newborn, with no significant past medical history, was referred to our department for treatment of an acute respiratory distress syndrome of neurological origin at day 8 of life. At birth, she presented with 3 small angiomatous papules and 4 subcutaneous nodules suggestive of neonatal hae-mangiomatosis (NH) (Fig. 1). A brain MRI revealed a highly vascularised brain stem tumour suggestive of glioma (Fig. 2), associated with 2 abnormal hepatic lesions consistent with infantile haemangiomas (IH) on ultrasound and CT scan. Methylprednisolone was started for the suspected glioma-associated oedema, and vincristine and propranolol were introduced for NH. After initial improvement, an acute intracranial hypertension related to cystic evolution of the disease necessitated surgical resection at the age of 2 months. Pathological examinations of the brain, cutaneous and subcutaneous lesions were similar, showing a vascular lobular proliferation of capillaries highly suggestive of PG. The misdiagnosis of glioma was eliminated. The GLUT-1 antigen marker was negative, ruling out the diagnosis of NH-like infantile haemangioma (Fig. 3). Lymphatic marker (D2-40) was also negative and eliminated a multifocal lymphangioendotheliomato-sis with thrombocytopaenia (MLT). Cutaneous and hepatic lesions gradually regressed. She is currently in complete remission after completing a treatment over 18 months with propranolol but a spontaneous improvement can not be excluded. DISCUSSIO
Anthropogenic VOCs in Abidjan, southern West Africa : From source quantification to atmospheric impacts
Several field campaigns were conducted in the framework of the Dynamics-Aerosol-Chemistry-Cloud Interactions in West Africa (DACCIWA) project to measure a broad range of atmospheric constituents. Here we present the analysis of an unprecedented and comprehensive dataset integrating up to 56 volatile organic compounds (VOCs) from ambient sites and emission sources. VOCs were collected on multi-sorbent tubes in the coastal city of Abidjan, Côte d'Ivoire, in winter and summer 2016 and later analysed by gas chromatography coupled with flame ionization and mass spectrometer detectors (GC-FID and GC-MS) at the laboratory. The comparison between VOC emission source profiles and ambient profiles suggests the substantial impact of two-stroke motorized two-wheel vehicles and domestic fires on the composition of Abidjan's atmosphere. However, despite high VOC concentrations near-source, moderate ambient levels were observed (by factors of 10 to 4000 lower), similar to the concentrations observed in northern mid-latitude urban areas. Besides photochemistry, the reported high wind speeds seem to be an essential factor that regulates air pollution levels in Abidjan. Emission ratios (ΔVOC/CO) were established based on real-world measurements achieved for a selected number of representative combustion sources. Maximum measured molar mass emissions were observed from two-wheel vehicles, surpassing other regional sources by 2 orders of magnitude. Local practices like waste burning also make a significant contribution to VOC emissions, higher than those from light-duty vehicles by 1.5 to 8 orders of magnitude. These sources also largely govern the VOC's atmospheric impacts in terms of OH reactivity, secondary organic aerosol formation (SOAP), and photochemical ozone creation potential (POCP). While the contribution of aromatics dominates the atmospheric impact, our measurements reveal the systematic presence of anthropogenic terpenoids in all residential combustion sectors. Finally, emission factors were used to retrieve and quantify VOC emissions from the main anthropogenic source sectors at the national level. Our detailed estimation of VOC emissions suggests that the road transport sector is the dominant source in Côte d'Ivoire, emitting around 1200Gg yr-1 of gas-phase VOCs. These new estimates are 100 and 160 times larger than global inventory estimations from MACCity or EDGAR (v4.3.2), respectively. Additionally, the residential sector is largely underestimated in the global emission inventories, by factors of 13 to 43. Considering only Côte d'Ivoire, these new estimates for VOCs are 3 to 6 times higher than the whole of Europe. Given the significant underestimation of VOC emissions from the transport and residential sectors in Côte d'Ivoire, there is an urgent need to build more realistic and region-specific emission inventories for the entire West African region. This might be true not only for VOCs, but also for all atmospheric pollutants. The lack of waste burning, wood fuel burning and charcoal burning, and fabrication representation in regional inventories also needs to be addressed, particularly in low-income areas where these types of activities are ubiquitous sources of VOC emissions
Low-grade extraskeletal osteosarcoma of the chest wall: case report and review of literature
<p>Abstract</p> <p>Background</p> <p>Low-grade extraskeletal osteosarcomas (ESOS) are extremely rare.</p> <p>Case presentation</p> <p>We present the first case of low-grade ESOS of the chest wall, which occurred in a 30-year-old man. Because of initial misdiagnosis and patient's refusal of surgery, the diagnosis was done after a 4-year history of a slowly growing mass in soft tissues, leading to a huge (30-cm diameter) calcified mass locally extended over the left chest wall. Final diagnosis was helped by molecular analysis of <it>MDM2 </it>and <it>CDK4 </it>oncogenes. Unfortunately, at this time, no surgical treatment was possible due to loco-regional extension, and despite chemotherapy, the patient died one year after diagnosis, five years after the first symptoms.</p> <p>Conclusion</p> <p>We describe the clinical, radiological and bio-pathological features of this unique case, and review the literature concerning low-grade ESOS. Our case highlights the diagnostic difficulties for such very rare tumours and the interest of molecular analysis in ambiguous cases.</p
Hidden chromosomal abnormalities in pleuropulmonary blastomas identified by multiplex FISH
BACKGROUND: Pleuropulmonary blastoma (PPB) is a rare childhood dysontogenetic intrathoracic neoplasm associated with an unfavourable clinical behaviour. CASES PRESENTATION: We report pathological and cytogenetic findings in two cases of PPB at initial diagnosis and recurrence. Both tumors were classified as type III pneumoblastoma and histological findings were similar at diagnosis and relapse. In both cases, conventional cytogenetic techniques revealed complex numerical and structural chromosomal abnormalities. Molecular cytogenetic analysis (interphase/metaphase FISH and multicolor FISH) identified accurately chromosomal aberrations. In one case, TP53 gene deletion was detected on metaphase FISH. To date, only few cytogenetic data have been published about PPB. CONCLUSION: The PPB genetic profile remains to be established and compared to others embryonal neoplasia. Our cytogenetic data are discussed reviewing cytogenetics PPBs published cases, illustrating the contribution of multicolor FISH in order to identify pathogenetically important recurrent aberrations in PPB
Contrasted Effects of Diversity and Immigration on Ecological Insurance in Marine Bacterioplankton Communities
The ecological insurance hypothesis predicts a positive effect of species richness on ecosystem functioning in a variable environment. This effect stems from temporal and spatial complementarity among species within metacommunities coupled with optimal levels of dispersal. Despite its importance in the context of global change by human activities, empirical evidence for ecological insurance remains scarce and controversial. Here we use natural aquatic bacterial communities to explore some of the predictions of the spatial and temporal aspects of the ecological insurance hypothesis. Addressing ecological insurance with bacterioplankton is of strong relevance given their central role in fundamental ecosystem processes. Our experimental set up consisted of water and bacterioplankton communities from two contrasting coastal lagoons. In order to mimic environmental fluctuations, the bacterioplankton community from one lagoon was successively transferred between tanks containing water from each of the two lagoons. We manipulated initial bacterial diversity for experimental communities and immigration during the experiment. We found that the abundance and production of bacterioplankton communities was higher and more stable (lower temporal variance) for treatments with high initial bacterial diversity. Immigration was only marginally beneficial to bacterial communities, probably because microbial communities operate at different time scales compared to the frequency of perturbation selected in this study, and of their intrinsic high physiologic plasticity. Such local “physiological insurance” may have a strong significance for the maintenance of bacterial abundance and production in the face of environmental perturbations
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