"Qui sommes-nous" et qui nous ne sommes pas : l'identité américaine mise à mal à sa frontière Sud

La construction par le gouvernement nord-américain d’un mur le long de la frontière avec le Mexique, dès 2006, ainsi que les politiques migratoires toujours plus restrictives, visent à l’endiguement des flux de migrants clandestins. L’État de l’Arizona, en tentant d’introduire une « loi sur le renforcement de l’application de nos lois et de la sécurité de nos quartiers » en avril 2010 a franchi un pas supplémentaire et suscité une vive controverse. Le texte est en effet l’un des plus restrictifs au monde en matière d’immigration et normalise le « délit de faciès ». À la racine de ce phénomène de fermeture progressive se trouve le besoin des États-Unis d’asseoir leur pouvoir dans une zone toujours plus poreuse et imprégnée d’« hispanité ». Pour certains, avant tout parmi les néoconservateurs, c’est même l’identité américaine qui est en jeu

Les murs, ou la marque visible de l'exclusion

Depuis la chute du mur de Berlin et, par conséquent, la fin d’une logique bipolaire qui a marqué les relations internationales pendant près de cinquante ans, on observe, en parallèle avec l’intensification des processus de mondialisation, une parcellisation du monde. Pendant que les élites profitent des bienfaits de la globalisation, les exclus sont les premières victimes de cette fragmentation. Un mur économique, toujours plus haut, sépare les privilégiés des autres. Au-delà de la métaphore, on constate la construction bien réelle de murs de ségrégation, aux quatre coins de la planète. En Amérique latine, continent où la fracture sociale est la plus visible, le phénomène attire l’attention. Ainsi, la ville de Rio a-t-elle entrepris, début 2009, la construction d’un mur pour encercler la favela de Dona Marta, située à proximité d’un quartier résidentiel, avec l’excuse officielle de protéger la forêt primaire attenante. A Buenos Aires, quelques mois plus tard, un mur a commencé à s’ériger entre une zone résidentielle et un quartier populaire, avant que le projet ne soit gelé par les autorités. Deux exemples qui illustrent une nouvelle stratégie face à la violence et à l’insécurité : la relégation « sociospatiale » et le confinement des indésirables derrière des murs

Modal Decomposition in Goalpost Micro/nano Electro-mechanical Devices

We have studied the first three symmetric out-of-plane flexural resonance modes of a goalpost silicon micro-mechanical device. Measurements have been performed at 4.2K in vacuum, demonstrating high Qs and good linear properties. Numerical simulations have been realized to fit the resonance frequencies and produce the mode shapes. These mode shapes are complex, since they involve distortions of two coupled orthogonal bars. Nonetheless, analytic expressions have been developed to reproduce these numerical results, with no free parameters. Owing to their generality they are extremely helpful, in particular to identify the parameters which may limit the performances of the device. The overall agreement is very good, and has been verified on our nano-mechanical version of the device.Comment: Journal of Low Temperature Physics (2013

Naval officer selection in Canada : an evaluation of the Maritime Officer Selection Test (MOST)

ix, 103 leaves : ill. ; 28 cm.Includes abstract.Includes bibliographical references (leaves 69-78).Two studies evaluating the Maritime Officer Selection Test (MOST) were conducted. Study 1 ( N = 744) examined the psychometric properties of the individual items and their factorial structure. Study 2 ( N = 224) assessed convergent validity and sought to determine whether using the MOST for the selection of future naval officers might discriminate against women, thereby precluding them from pursuing a career within the Canadian Navy. The results of the first study indicate that most examinees do not have enough time to complete the test, which invalidates previous evaluations of its internal consistency. Additionally, the two studies suggest that the MOST does not measure what it was intended to assess (i.e., memory, selective attention, and decision-making), but that it does nonetheless evaluate other ability constructs required for naval officer training performance (i.e., spatial scanning and general reasoning). With regards to adverse effect, the absence of differential item functioning and similarities in success rates across genders indicate that using the MOST does not preclude women from pursuing a career within the Canadian Navy

Average Metallicity and Star Formation Rate of Lya Emitters Probed by a Triple Narrow-Band Survey

We present the average metallicity and star-formation rate of Lya emitters (LAEs) measured from our large-area survey with three narrow-band (NB) filters covering the Lya, [OII]3727, and Ha+[NII] lines of LAEs at z=2.2. We select 919 z=2.2 LAEs from Subaru/Suprime-Cam NB data in conjunction with Magellan/IMACS spectroscopy. Of these LAEs, 561 and 105 are observed with KPNO/NEWFIRM near-infrared NB filters whose central wavelengths are matched to redshifted [OII] and Ha nebular lines, respectively. By stacking the near-infrared images of the LAEs, we successfully obtain average nebular-line fluxes of LAEs, the majority of which are too faint to be identified individually by narrow-band imaging or deep spectroscopy. The stacked object has an Ha luminosity of 1.7x10^{42} erg s^{-1} corresponding to a star formation rate (SFR) of 14 M_{sun} yr^{-1}. We place, for the first time, a firm lower limit to the average metallicity of LAEs of Z>~0.09 Z_{sun} (2sigma) based on the [OII]/(Ha+[NII]) index together with photo-ionization models and empirical relations. This lower limit of metallicity rules out the hypothesis that LAEs, so far observed at z~2, are extremely metal poor (Z<2x10^{-2} Z_{sun}) young galaxies at the 4sigma level. This limit is higher than a simple extrapolation of the observed mass-metallicity relation of z~2 UV-selected galaxies toward lower masses (5x10^{8} M_{sun}), but roughly consistent with a recently proposed fundamental mass-metallicity relation when the LAEs' relatively low SFR is taken into account. The Ha and Lya luminosities of our NB-selected LAEs indicate that the escape fraction of Lya photons is ~12-30 %, much higher than the values derived for other galaxy populations at z~2.Comment: 21 pages, 15 figures, 8 tables. Accepted for publication in Ap

Thirty years of HIV pregnancies in French Guiana: prevention successes and remaining obstetrical challenges

IntroductionIn a context of high HIV prevalence, poor pregnancy follow-up, frequent poverty, preeclampsia, and preterm delivery, we aimed to describe the characteristics and outcomes of pregnancies among women living with HIV in French Guiana.MethodsA retrospective cohort study was conducted on HIV-infected pregnancies enrolled between January 1st 1992 to 31st July 2022. Overall, there were 1,774 pregnancies in 881 women living with HIV.ResultsFor 75.1% of pregnancies, the HIV diagnosis was already known before pregnancy and in 67.6% of women, HIV follow-up predated pregnancy. Nearly half of women, 49.6%, only had one pregnancy since having been diagnosed with HIV. Although most women received antiretroviral therapy during pregnancy, for those with the available information we found only 48.5% had an undetectable viral load at delivery. Overall, 15.3% of pregnancies ended with an abortion. There were a total of 110 newborns infected with HIV representing an overall transmission rate of 6.2% (110/1,771). Between 1993 and 2002, the transmission rate was 34%, between 2003 and 2012 it was 1.3%, and between 2013 and 2022 it was 0.7%. Overall, in Cayenne, since 2008, 106 of 581 HIV–infected pregnancies (18.2%) with available information were premature before 37 weeks of pregnancy; of these, 33 (5.7%) were very preterm deliveries and 73 (13.3%) were late preterm deliveries. Over time, in Cayenne, preterm delivery declined significantly.ConclusionsThe present study emphasizes that, despite spectacular progress in reducing mother to child transmission, pregnancy outcomes among women living with HIV are still preoccupying with high incidence of preterm delivery and low birth weight. Teasing out what fraction is linked to HIV and what fraction is linked to social precariousness and poor follow-up was not possible in this study. Despite the high incidence of very preterm delivery recent progress suggests that coordination efforts to improve follow-up may also have improved obstetrical outcomes

The Fourteenth Data Release of the Sloan Digital Sky Survey: First Spectroscopic Data from the extended Baryon Oscillation Spectroscopic Survey and from the second phase of the Apache Point Observatory Galactic Evolution Experiment

The fourth generation of the Sloan Digital Sky Survey (SDSS-IV) has been in operation since July 2014. This paper describes the second data release from this phase, and the fourteenth from SDSS overall (making this, Data Release Fourteen or DR14). This release makes public data taken by SDSS-IV in its first two years of operation (July 2014-2016). Like all previous SDSS releases, DR14 is cumulative, including the most recent reductions and calibrations of all data taken by SDSS since the first phase began operations in 2000. New in DR14 is the first public release of data from the extended Baryon Oscillation Spectroscopic Survey (eBOSS); the first data from the second phase of the Apache Point Observatory (APO) Galactic Evolution Experiment (APOGEE-2), including stellar parameter estimates from an innovative data driven machine learning algorithm known as "The Cannon"; and almost twice as many data cubes from the Mapping Nearby Galaxies at APO (MaNGA) survey as were in the previous release (N = 2812 in total). This paper describes the location and format of the publicly available data from SDSS-IV surveys. We provide references to the important technical papers describing how these data have been taken (both targeting and observation details) and processed for scientific use. The SDSS website (www.sdss.org) has been updated for this release, and provides links to data downloads, as well as tutorials and examples of data use. SDSS-IV is planning to continue to collect astronomical data until 2020, and will be followed by SDSS-V.Comment: SDSS-IV collaboration alphabetical author data release paper. DR14 happened on 31st July 2017. 19 pages, 5 figures. Accepted by ApJS on 28th Nov 2017 (this is the "post-print" and "post-proofs" version; minor corrections only from v1, and most of errors found in proofs corrected

Arbovirus-Derived piRNAs Exhibit a Ping-Pong Signature in Mosquito Cells

The siRNA pathway is an essential antiviral mechanism in insects. Whether other RNA interference pathways are involved in antiviral defense remains unclear. Here, we report in cells derived from the two main vectors for arboviruses, Aedes albopictus and Aedes aegypti, the production of viral small RNAs that exhibit the hallmarks of ping-pong derived piwi-associated RNAs (piRNAs) after infection with positive or negative sense RNA viruses. Furthermore, these cells produce endogenous piRNAs that mapped to transposable elements. Our results show that these mosquito cells can initiate de novo piRNA production and recapitulate the ping-pong dependent piRNA pathway upon viral infection. The mechanism of viral-piRNA production is discussed

Associations among hypertension, dementia biomarkers, and cognition: The MEMENTO cohort

Introduction Approximately 40% of dementia cases could be delayed or prevented acting on modifiable risk factors including hypertension. However, the mechanisms underlying the hypertension–dementia association are still poorly understood. Methods We conducted a cross-sectional analysis in 2048 patients from the MEMENTO cohort, a French multicenter clinic-based study of outpatients with either isolated cognitive complaints or mild cognitive impairment. Exposure to hypertension was defined as a combination of high blood pressure (BP) status and antihypertensive treatment intake. Pathway associations were examined through structural equation modeling integrating extensive collection of neuroimaging biomarkers and clinical data. Results Participants treated with high BP had significantly lower cognition compared to the others. This association was mediated by higher neurodegeneration and higher white matter hyperintensities load but not by Alzheimer's disease (AD) biomarkers. Discussion These results highlight the importance of controlling hypertension for prevention of cognitive decline and offer new insights on mechanisms underlying the hypertension–dementia association. Highlights Paths of hypertension–cognition association were assessed by structural equation models. The hypertension–cognition association is not mediated by Alzheimer's disease biomarkers. The hypertension–cognition association is mediated by neurodegeneration and leukoaraiosis. Lower cognition was limited to participants treated with uncontrolled blood pressure. Blood pressure control could contribute to promote healthier brain aging.Stopping cognitive decline and dementia by fighting covert cerebral small vessel diseas