175 research outputs found
Characterization of the Evolution of IC Emissions after Accelerated Aging
9 pagesInternational audienceWith the evolving technological development of integrated circuits (ICs), ensuring electromagnetic compatibility (EMC) is becoming a serious challenge for electronic circuit and system manufacturers. Although electronic components must pass a set of EMC tests to ensure safe operations, the evolution over time of EMC is not characterized and cannot be accurately forecast. This paper presents an original study about the consequences of the aging of circuits on electromagnetic emission. Different types of standard applicative and accelerated-life tests are applied on a mixed power circuit dedicated to automotive applications. Its conducted emission is measured before and after these tests showing variations in EMC performances. Comparisons between each type of aging procedure show that the emission level of the circuit under test is affected differently
Logistik: Hur pÄverkar Just-In-Time pÄ lönsamheten av ett företag?
Ett företag har som grunduppgift att hÄllas verksamt genom att ekonomiskt prestera bÀttre för varje Är. Logistik Àr det verksamhetsomrÄde som stÄr för majoriteten av ett företags kostnader. Kostnader i sig Àr en dÄlig sak för företag, men det Àr Àven en möjlighet för logistiken att sÀnka dessa kostnader, vilket i sin tur Àr bra för företagets lön-samhet. Just-In-Time (JIT) Àr en produktions- och styrfilosofi inom logistiken, dÀr det huvudsakliga mÄlet Àr att minska lagernivÄerna och att eliminera allt onödigt. Syftet med denna studie Àr att finna ett samband mellan JIT och lönsamhet ur ett logistiskt perspektiv. Vid studien anvÀnds DuPont-modellen som definition av lönsamhet samt som ett jÀmförelseverktyg dÀr sex olika finansiella faktorer mÀts. Metoden för studien Àr kvalitativ i form av en litteraturstudie. Materialet som analyseras hÀmtas endast frÄn Arcadas databaser och analysen av materialet sker i form av innehÄllsanalys. Resultaten av materialet som analyserades Àr vÀldigt blandat. MÄnga studier pÄpekar att det rÄder brist pÄ forskning inom detta ÀmnesomrÄdet, vilket Àven kan vara orsaken till dessa blandade resultat. Det gÄr dock att urskilja tre finansiella mÄtt frÄn DuPont-modellen som pÄver-kas positivt av JIT. Dessa Àr: intÀkter, kostnader och lager. Ingen studie visade att JIT skulle ha negativ inverkan pÄ ett företags lönsamhet. Andra intressanta faktorer som JIT hade en positiv inverkan pÄ Àr operativa prestanda, t.ex. minskade ledtider
Combining ground-based microwave radiometer and the AROME convective scale model through 1DVAR retrievals in complex terrain: an Alpine valley case study
Abstract. A RPG-HATPRO ground-based microwave radiometer (MWR) was operated in a deep Alpine valley during the Passy-2015 field campaign. This experiment aims to investigate how stable boundary layers during wintertime conditions drive the accumulation of pollutants. In order to understand the atmospheric processes in the valley, MWRs continuously provide vertical profiles of temperature and humidity at a high time frequency, providing valuable information to follow the evolution of the boundary layer. A one-dimensional variational (1DVAR) retrieval technique has been implemented during the field campaign to optimally combine an MWR and 1âŻh forecasts from the French convective scale model AROME. Retrievals were compared to radiosonde data launched at least every 3âŻh during two intensive observation periods (IOPs). An analysis of the AROME forecast errors during the IOPs has shown a large underestimation of the surface cooling during the strongest stable episode. MWR brightness temperatures were monitored against simulations from the radiative transfer model ARTS2 (Atmospheric Radiative Transfer Simulator) and radiosonde launched during the field campaign. Large errors were observed for most transparent channels (i.e., 51â52âŻGHz) affected by absorption model and calibration uncertainties while a good agreement was found for opaque channels (i.e., 54â58âŻGHz). Based on this monitoring, a bias correction of raw brightness temperature measurements was applied before the 1DVAR retrievals. 1DVAR retrievals were found to significantly improve the AROME forecasts up to 3âŻkm but mainly below 1âŻkm and to outperform usual statistical regressions above 1âŻkm. With the present implementation, a root-mean-square error (RMSE) of 1âŻK through all the atmospheric profile was obtained with values within 0.5âŻK below 500âŻm in clear-sky conditions. The use of lower elevation angles (up to 5°) in the MWR scanning and the bias correction were found to improve the retrievals below 1000âŻm. MWR retrievals were found to catch deep near-surface temperature inversions very well. Larger errors were observed in cloudy conditions due to the difficulty of ground-based MWRs to resolve high level inversions that are still challenging. Finally, 1DVAR retrievals were optimized for the analysis of the IOPs by using radiosondes as backgrounds in the 1DVAR algorithm instead of the AROME forecasts. A significant improvement of the retrievals in cloudy conditions and below 1000âŻm in clear-sky conditions was observed. From this study, we can conclude that MWRs are expected to bring valuable information into numerical weather prediction models up to 3âŻkm in altitude both in clear-sky and cloudy-sky conditions with the maximum improvement found around 500âŻm. With an accuracy between 0.5 and 1âŻK in RMSE, our study has also proven that MWRs are capable of resolving deep near-surface temperature inversions observed in complex terrain during highly stable boundary layer conditions
Effets comparatifs des acides gras omega-3 (ALA, EPA, DHA) sur la sensibilitĂ© Ă lâinsuline des cellules musculaires C2C12 dans un contexte lipotoxique
Objectifs :Etudier le rĂŽle des Ï3 sur la lipotoxicitĂ© induite par lâacide gras saturĂ© palmitate (PAL, C16:0) dans un modĂšle de cellule musculaire C2C12.Identifier les effets propres de chaque w3 (ALA, EPA et DHA) Ă dose Ă©quivalente sur la fluiditĂ© des membranes et la rĂ©ponse Ă lâinsuline.Suivre le devenir intracellulaire du [1-14C]-palmitate en prĂ©sence dâun w3 et dĂ©finir les classes de lipides altĂ©rĂ©es.Rechercher les voies de signalisation impliquĂ©es dans la modulation de la rĂ©ponse Ă lâinsuline
J Clin Med
We aimed to describe the burden represented by potentially inappropriate medications (PIMs) in chronic polypharmacy in France. We conducted a nationwide cross-sectional study using data from the French National Insurance databases. The study period was from 1 January 2016 to 31 December 2016. Chronic drug use was defined as uninterrupted daily use lasting ?6 months. Chronic polypharmacy was defined as the chronic use of ?5 medications, and chronic hyperpolypharmacy as the chronic use of ?10 medications. For individuals aged ?65 (older adults), PIMs were defined according to the Beers and Laroche lists, and for individuals aged 45-64 years (middle-aged) PIMs were defined according to the PROMPT (Prescribing Optimally in Middle-aged People's Treatments) list. Among individuals with chronic polypharmacy, 4009 (46.2%) middle-aged and 18,036 (64.8%) older adults had at least one chronic PIM. Among individuals with chronic hyperpolypharmacy, these figures were, respectively, 570 (75.0%) and 2544 (88.7%). The most frequent chronic PIM were proton pump inhibitors (43.4% of older adults with chronic polypharmacy), short-acting benzodiazepines (older adults: 13.7%; middle-aged: 16.1%), hypnotics (6.1%; 7.4%), and long-acting sulfonylureas (3.9%; 12.3%). The burden of chronic PIM appeared to be very high in our study, concerning almost half of middle-aged adults and two-thirds of older adults with chronic polypharmacy. Deprescribing interventions in polypharmacy should primarily target proton pump inhibitors and hypnotics
Sine-Gordon mean field theory of a Coulomb Gas
Sine-Gordon field theory is used to investigate the phase diagram of a
neutral Coulomb gas. A variational mean field free energy is constructed and
the corresponding phase diagrams in two (2d) and three dimensions (3d) are
obtained. When analyzed in terms of chemical potential, the Sine-Gordon theory
predicts the phase diagram topologically identical with the Monte Carlo
simulations and a recently developed Debye-H\"uckel-Bjerrum (DHBj) theory. In
2d we find that the infinite order Kosterlitz-Thouless line terminates in a
tricritical point, after which the metal-insulator transition becomes first
order. However, when the transformation from chemical potential to the density
is made the whole of the insulating phase is mapped onto zero density.Comment: 5 pages, Revtex with twocolumn style, 2 Postscript figures. Submitted
to PR
OPV strains circulation in HIV infected infants after National Immunisation Days in Bangui, Central African Republic
<p>Abstract</p> <p>Background</p> <p>Humans are the only host of polioviruses, thus the prospects of global polio eradication look reasonable. However, individuals with immunodeficiencies were shown to excrete vaccine derived poliovirus for long periods of time which led to reluctance to prolong the vaccination campaign for fear of this end result. Therefore, we aimed to assess the duration of excretion of poliovirus after the 2001 National Immunization Days according to Human immunodeficiency virus status.</p> <p>Findings</p> <p>Fifty three children were enrolled. Sequential stool samples were collected in between National Immunisation Days rounds and then every month during one year. Children were classified into 2 groups: no immunodepression (n = 38), immunodepression (n = 15) according to CD4+ lymphocytes cells count. Thirteen poliovirus strains were isolated from 11 children: 5 Human immunodeficiency virus positive and 6 Human immunodeficiency virus negative. None of the children excreted poliovirus for more than 4 weeks. The restriction fragment length polymorphism analysis showed that all strains were of Sabin origin including a unique Polio Sabine Vaccine types 2 and 3 (S2/S3) recombinant.</p> <p>Conclusions</p> <p>From these findings we assume that Human immunodeficiency virus positive children are not a high risk population for long term poliovirus excretion. More powerful studies are needed to confirm our findings.</p
A chemical survey of exoplanets with ARIEL
Thousands of exoplanets have now been discovered with a huge range of masses, sizes and orbits: from rocky Earth-like planets to large gas giants grazing the surface of their host star. However, the essential nature of these exoplanets remains largely mysterious: there is no known, discernible pattern linking the presence, size, or orbital parameters of a planet to the nature of its parent star. We have little idea whether the chemistry of a planet is linked to its formation environment, or whether the type of host star drives the physics and chemistry of the planetâs birth, and evolution. ARIEL was conceived to observe a large number (~1000) of transiting planets for statistical understanding, including gas giants, Neptunes, super-Earths and Earth-size planets around a range of host star types using transit spectroscopy in the 1.25â7.8 ÎŒm spectral range and multiple narrow-band photometry in the optical. ARIEL will focus on warm and hot planets to take advantage of their well-mixed atmospheres which should show minimal condensation and sequestration of high-Z materials compared to their colder Solar System siblings. Said warm and hot atmospheres are expected to be more representative of the planetary bulk composition. Observations of these warm/hot exoplanets, and in particular of their elemental composition (especially C, O, N, S, Si), will allow the understanding of the early stages of planetary and atmospheric formation during the nebular phase and the following few million years. ARIEL will thus provide a representative picture of the chemical nature of the exoplanets and relate this directly to the type and chemical environment of the host star. ARIEL is designed as a dedicated survey mission for combined-light spectroscopy, capable of observing a large and well-defined planet sample within its 4-year mission lifetime. Transit, eclipse and phase-curve spectroscopy methods, whereby the signal from the star and planet are differentiated using knowledge of the planetary ephemerides, allow us to measure atmospheric signals from the planet at levels of 10â100 part per million (ppm) relative to the star and, given the bright nature of targets, also allows more sophisticated techniques, such as eclipse mapping, to give a deeper insight into the nature of the atmosphere. These types of observations require a stable payload and satellite platform with broad, instantaneous wavelength coverage to detect many molecular species, probe the thermal structure, identify clouds and monitor the stellar activity. The wavelength range proposed covers all the expected major atmospheric gases from e.g. H2O, CO2, CH4 NH3, HCN, H2S through to the more exotic metallic compounds, such as TiO, VO, and condensed species. Simulations of ARIEL performance in conducting exoplanet surveys have been performed â using conservative estimates of mission performance and a full model of all significant noise sources in the measurement â using a list of potential ARIEL targets that incorporates the latest available exoplanet statistics. The conclusion at the end of the Phase A study, is that ARIEL â in line with the stated mission objectives â will be able to observe about 1000 exoplanets depending on the details of the adopted survey strategy, thus confirming the feasibility of the main science objectives.Peer reviewedFinal Published versio
Deliberate and Accidental Gas-Phase Alkali Doping of Chalcogenide Semiconductors: Cu(In,Ga)Se2
Alkali metal doping is essential to achieve highly efficient energy conversion in Cu(In,Ga)Se2 (CIGSe) solar cells. Doping is normally achieved through solid state reactions, but recent observations of gas phase alkali transport in the kesterite sulfide (Cu2ZnSnS4) system (re)open the way to a novel gas-phase doping strategy. However, the current understanding of gas-phase alkali transport is very limited. This work (i) shows that CIGSe device efficiency can be improved from 2% to 8% by gas-phase sodium incorporation alone, (ii) identifies the most likely routes for gas-phase alkali transport based on mass spectrometric studies, (iii) provides thermochemical computations to rationalize the observations and (iv) critically discusses the subject literature with the aim to better understand the chemical basis of the phenomenon. These results suggest that accidental alkali metal doping occurs all the time, that a controlled vapor pressure of alkali metal could be applied during growth to dope the semiconductor, and that it may have to be accounted for during the currently used solid state doping routes. It is concluded that alkali gas-phase transport occurs through a plurality of routes and cannot be attributed to one single source
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