79 research outputs found
Anomalous photon diffusion in atomic vapors
The multiple scattering of photons in a hot, resonant, atomic vapor is
investigated and shown to exhibit a L\'evy Flight-like behavior. Monte Carlo
simulations give insights into the frequency redistribution process that
originates the long steps characteristic of this class of random walk
phenomena
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Near-offset vertical seismic experiments during leg 204
Three successful vertical seismic profiles (VSPs) were acquired during
Ocean Drilling Program (ODP) Leg 204 at South Hydrate Ridge. The
data confirm earlier results from ocean bottom seismometer data and
analysis of moveout from common midpoint reflection data that the
average velocity between the seafloor and the bottom-simulating reflector
(BSR) is <1600 m/s throughout the region and is lowest near the
summit, where the amount of hydrate is greatest. This result supports
the conclusions that free gas and hydrate coexist beneath the summit
and that the average amount of gas hydrate present elsewhere is low.
The data also indicate that low-velocity zones (LVZs) resulting from free
gas beneath the BSR must be thin and stratigraphically controlled. The
only LVZ resolvable from traveltime analysis of the VSP data is associated
with Horizon A, which has been interpreted to be the primary conduit
transporting free gas to vents at the summit of South Hydrate
Ridge. Thin LVZs associated with Horizons B and B', however, are indicated
by sonic logs as well as by strong negative polarity reflections in
the multichannel seismic data. This limited distribution of sub-BSR free
gas contrasts with previous results at North Hydrate Ridge (Leg 146)
and Blake Ridge (Leg 164), which indicate the presence of free gas zones
several hundred meters thick that result in distinct LVZs in the VSP data
from those earlier ODP legs
TRY plant trait database – enhanced coverage and open access
Plant traits - the morphological, anatomical, physiological, biochemical and phenological characteristics of plants - determine how plants respond to environmental factors, affect other trophic levels, and influence ecosystem properties and their benefits and detriments to people. Plant trait data thus represent the basis for a vast area of research spanning from evolutionary biology, community and functional ecology, to biodiversity conservation, ecosystem and landscape management, restoration, biogeography and earth system modelling. Since its foundation in 2007, the TRY database of plant traits has grown continuously. It now provides unprecedented data coverage under an open access data policy and is the main plant trait database used by the research community worldwide. Increasingly, the TRY database also supports new frontiers of trait‐based plant research, including the identification of data gaps and the subsequent mobilization or measurement of new data. To support this development, in this article we evaluate the extent of the trait data compiled in TRY and analyse emerging patterns of data coverage and representativeness. Best species coverage is achieved for categorical traits - almost complete coverage for ‘plant growth form’. However, most traits relevant for ecology and vegetation modelling are characterized by continuous intraspecific variation and trait–environmental relationships. These traits have to be measured on individual plants in their respective environment. Despite unprecedented data coverage, we observe a humbling lack of completeness and representativeness of these continuous traits in many aspects. We, therefore, conclude that reducing data gaps and biases in the TRY database remains a key challenge and requires a coordinated approach to data mobilization and trait measurements. This can only be achieved in collaboration with other initiatives
Mortality from gastrointestinal congenital anomalies at 264 hospitals in 74 low-income, middle-income, and high-income countries: a multicentre, international, prospective cohort study
Summary
Background Congenital anomalies are the fifth leading cause of mortality in children younger than 5 years globally.
Many gastrointestinal congenital anomalies are fatal without timely access to neonatal surgical care, but few studies
have been done on these conditions in low-income and middle-income countries (LMICs). We compared outcomes of
the seven most common gastrointestinal congenital anomalies in low-income, middle-income, and high-income
countries globally, and identified factors associated with mortality.
Methods We did a multicentre, international prospective cohort study of patients younger than 16 years, presenting to
hospital for the first time with oesophageal atresia, congenital diaphragmatic hernia, intestinal atresia, gastroschisis,
exomphalos, anorectal malformation, and Hirschsprung’s disease. Recruitment was of consecutive patients for a
minimum of 1 month between October, 2018, and April, 2019. We collected data on patient demographics, clinical
status, interventions, and outcomes using the REDCap platform. Patients were followed up for 30 days after primary
intervention, or 30 days after admission if they did not receive an intervention. The primary outcome was all-cause,
in-hospital mortality for all conditions combined and each condition individually, stratified by country income status.
We did a complete case analysis.
Findings We included 3849 patients with 3975 study conditions (560 with oesophageal atresia, 448 with congenital
diaphragmatic hernia, 681 with intestinal atresia, 453 with gastroschisis, 325 with exomphalos, 991 with anorectal
malformation, and 517 with Hirschsprung’s disease) from 264 hospitals (89 in high-income countries, 166 in middleincome
countries, and nine in low-income countries) in 74 countries. Of the 3849 patients, 2231 (58·0%) were male.
Median gestational age at birth was 38 weeks (IQR 36–39) and median bodyweight at presentation was 2·8 kg (2·3–3·3).
Mortality among all patients was 37 (39·8%) of 93 in low-income countries, 583 (20·4%) of 2860 in middle-income
countries, and 50 (5·6%) of 896 in high-income countries (p<0·0001 between all country income groups).
Gastroschisis had the greatest difference in mortality between country income strata (nine [90·0%] of ten in lowincome
countries, 97 [31·9%] of 304 in middle-income countries, and two [1·4%] of 139 in high-income countries;
p≤0·0001 between all country income groups). Factors significantly associated with higher mortality for all patients
combined included country income status (low-income vs high-income countries, risk ratio 2·78 [95% CI 1·88–4·11],
p<0·0001; middle-income vs high-income countries, 2·11 [1·59–2·79], p<0·0001), sepsis at presentation (1·20
[1·04–1·40], p=0·016), higher American Society of Anesthesiologists (ASA) score at primary intervention
(ASA 4–5 vs ASA 1–2, 1·82 [1·40–2·35], p<0·0001; ASA 3 vs ASA 1–2, 1·58, [1·30–1·92], p<0·0001]), surgical safety
checklist not used (1·39 [1·02–1·90], p=0·035), and ventilation or parenteral nutrition unavailable when needed
(ventilation 1·96, [1·41–2·71], p=0·0001; parenteral nutrition 1·35, [1·05–1·74], p=0·018). Administration of
parenteral nutrition (0·61, [0·47–0·79], p=0·0002) and use of a peripherally inserted central catheter (0·65
[0·50–0·86], p=0·0024) or percutaneous central line (0·69 [0·48–1·00], p=0·049) were associated with lower mortality.
Interpretation Unacceptable differences in mortality exist for gastrointestinal congenital anomalies between lowincome,
middle-income, and high-income countries. Improving access to quality neonatal surgical care in LMICs will
be vital to achieve Sustainable Development Goal 3.2 of ending preventable deaths in neonates and children younger
than 5 years by 2030
Activation d'oncogenes dans les adenocarcinomes mammaires humains : mise en evidence de facteurs moleculaires lies a la progression tumorale
SIGLECNRS T Bordereau / INIST-CNRS - Institut de l'Information Scientifique et TechniqueFRFranc
The expression of c-myb is strongly associated with the presence of estrogen and progesterone receptors in breast cancer
International audienceThe c-myb gene was studied in 112 breast cancers. c-myb and estrogen receptor (ER) transcripts were found in 78 (70%) and 71 (63%) cancers respectively. Of these 71 ER positive cancers, 64 (90%) contained c-myb transcripts and of the 41 ER negative cancers, 27 (66%) did not contain c-myb mRNA. Our data show that c-myb transcripts are strongly associated with ER and progesterone receptors (p less than 10(-4) status in breast cancer. Thus the c-myb expression could be associated with breast cancers of better prognosis and its analysis could allow a better characterization of new subsets of hormono-dependent cancers responding more efficiently to hormonotherapy
Analysis of the expression of the oncogene c-myc in human breast adenocarcinoma
International audienceThe c-myc oncogene was characterized and its expression analyzed in 32 mammary adenocarcinomas and in 2 benign breast tumors from 34 untreated patients. Southern blot hybridization experiments have demonstrated the amplification of the oncogene (3 to 30 fold) in 3 carcinomas. The analysis of total RNA by Northern blot revealed the presence of a 2.4 kb c-myc RNA band. In 7 out of 10 carcinomas from patients with 3 or more than 3 lymph node metastases the level of c-myc expression evaluated by dot blot analysis was 4 to 14 fold greater than that of normal human tissues. In only 5 out of 22 carcinomas from patients without lymph node metastases or less than 3 invaded nodes the level of c-myc expression was also higher (4 to 10 fold). The level of c-myc expression was not significantly enhanced in the 2 benign tumors. It is suggested that the c-myc gene activation could be associated to a higher degree of malignancy of mammary carcinomas
Impact des variations environnementales sur la structure des communautés mammaliennes et l'anthropisation des milieux (exemple des faunes holocènes du Sahara occidental)
A l'Holocène (de 10 ka à l'actuel), le climat d'abord humide évolue vers une aridification en Afrique de l'Ouest affectant la structure des communautés mammaliennes. Cette faune est obtenue à travers les restes d'ongulés associés aux occupations humaines. Les espèces présentes encore aujourd'hui montraient une distribution géographiques différentes. En utilisant les exigences écologiques des Bovidae, une méthode de calibrage environnemental a été mise au point, mettant en évidence les particularités locales par rapport au contexte climatique général. Une analyse biométique permet de reconnaître une évolution de la taille des ongulés en relation avec le changement environnemental. L'étude archéozoologique démontre un changement comportemental des hommes néolithiques. Jusque vers 2 ka, l'adoption de l'élevage bovin n'exclue pas la chasse et la pêche. Face à l'aridification, la diversification des activités est une adaptation des modes de subsistance liée à l'appauvrissement du gibier.LYON1-BU.Sciences (692662101) / SudocLYON1 - UFR Sciences de la terre (692662208) / SudocSudocFranceF
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