Excitation of equatorial Kelvin and Yanai waves by tropical cyclones in an ocean general circulation model

Tropical cyclones (TCs) actively contribute to the dynamics of Earth's coupled climate system. They influence oceanic mixing rates, upper-ocean heat content, and air–sea fluxes, with implications for atmosphere and ocean dynamics on multiple spatial and temporal scales. Using an ocean general circulation model with modified surface wind forcing, we explore how TC winds can excite equatorial ocean waves in the tropical Pacific. We highlight a situation where three successive TCs in the western North Pacific region, corresponding to events in 2003, excite a combination of Kelvin and Yanai waves in the equatorial Pacific. The resultant thermocline adjustment significantly modifies the thermal structure of the upper equatorial Pacific and leads to eastward zonal heat transport. Observations of upper-ocean temperature by the Tropical Atmosphere Ocean (TAO) buoy array and sea-level height anomalies using altimetry reveal wave passage during the same time period with similar properties to the modeled wave, although our idealized model methodology disallows precise identification of the TC forcing with the observed waves. Results indicate that direct oceanographic forcing by TCs may be important for understanding the spectrum of equatorial ocean waves, thus remotely influencing tropical mixing and surface energy budgets. Because equatorial Kelvin waves are closely linked to interannual variability in the tropical Pacific, these findings also suggest TC wind forcing may influence the timing and amplitude of El Niño events

Mechanisms of decadal North Atlantic climate variability and implications for the recent cold anomaly

Decadal sea surface temperature (SST) fluctuations in the North Atlantic Ocean influence climate over adjacent land areas and are a major source of skill in climate predictions. However, the mechanisms underlying decadal SST variability remain to be fully understood. This study isolates the mechanisms driving North Atlantic SST variability on decadal time scales using low-frequency component analysis, which identifies the spatial and temporal structure of low-frequency variability. Based on observations, large ensemble historical simulations, and preindustrial control simulations, we identify a decadal mode of atmosphere–ocean variability in the North Atlantic with a dominant time scale of 13–18 years. Large-scale atmospheric circulation anomalies drive SST anomalies both through contemporaneous air–sea heat fluxes and through delayed ocean circulation changes, the latter involving both the meridional overturning circulation and the horizontal gyre circulation. The decadal SST anomalies alter the atmospheric meridional temperature gradient, leading to a reversal of the initial atmospheric circulation anomaly. The time scale of variability is consistent with westward propagation of baroclinic Rossby waves across the subtropical North Atlantic. The temporal development and spatial pattern of observed decadal SST variability are consistent with the recent observed cooling in the subpolar North Atlantic. This suggests that the recent cold anomaly in the subpolar North Atlantic is, in part, a result of decadal SST variability.publishedVersio

Epidémiologie des bactéries multi résistantes dans un service de réanimation polyvalente d’un hôpital universitaire de Marrakech entre octobre 2006 et septembre 2009

The intensive care units, “the epicenter of resistance to antibiotics”, are and will remain the place where multidrug–resistant bacteria infections are more frequent, in spite of the preventive measures in force. Material and methods: This work is a retrospective study of 3 years duration (beginning in October 2006 to end of September 2009) reporting the epidemiology of the multidrug–resistant bacteria infections isolated from different bacteriological samples for diagnosis emanating from the ICU (intensive care unit) of Avicenna Military Hospital of Marrakesh (HMA). The identification of bacterial strains as well as the relative antibiogram are achieved by automated method and the resistance phenotypes are determined by the methods of agar diffusion as recommended by the antibiogram committee of the French Society of Microbiology. Results and discussion: Over a period of 03 years, 84 clinical isolates of multidrug-resistant bacteria were isolated from 414 pathological specimens from the ICU of the hospital. The multi-resistant bacterial strains (BMR) (n = 84) are largely predominated by Acinetobacter sp (n = 40) followed by Enterobacteria producing extended spectrum betalactamases (n = 26), Enterobacteria secreting hyperproduced céphalosporinases (n= 8), Pseudomonas aeruginosa resistant to the ceftazidime (n=6), and finally Staphylococcus aureus resistant to meticilline SARM (n=4). No enterocoque resistant to the glycopeptides was insulated. The evolution of multidrug resistance to antibiotics over the past 3 years, was marked by the emergence of Acinetobacter. The monitoring of bacterial multi resistance is a necessity in ICU provider of nosocomial infections.Introduction : Les services de réanimation, « épicentre de la résistance aux antibiotiques », sont et resteront le lieu où les infections à bactéries multi résistantes sont les plus fréquentes, malgré les mesures de prévention en vigueur. Matériel et méthodes : Le présent travail est une étude rétrospective d’une durée de 3 ans (début octobre 2006 à fin Septembre 2009) relatant l'épidémiologie des infections bactériennes multi résistantes isolées à partir des différents prélèvements bactériologiques à visée diagnostique émanant de l'unité de réanimation de l’Hôpital Militaire Avicenne de Marrakech (HMA). L’identification des souches bactériennes ainsi que l’antibiogramme relatif sont réalisés par méthode automatisée et les phénotypes de résistance sont déterminés par les méthodes de diffusion en milieu gélosé selon les recommandations du Comité de l’Antibiogramme de la Société Française de Microbiologie. Résultats et discussion : Sur une période de 03 ans, 84 isolats cliniques de bactéries multi résistantes ont été isolés à partir de 414 produits pathologiques émanant du service de réanimation de l’hôpital. Les souches bactériennes multi résistantes (BMR) (n=84) sont largement prédominées par l’Acinetobacter sp (n=40) suivi des entérobactéries productrices de Bétalactamases à spectre élargi (n=26), des entérobactéries sécrétrices de céphalosporinases hyperproduites (n= 8), de Pseudomonas aeruginosa résistant à la ceftazidime (n=6), et enfin des Staphylococcus aureus résistant à la méticilline SARM (n=4). Aucun entérocoque résistant aux glycopeptides n’a été isolé. L’évolution de la multi résistance aux antibiotiques au cours des 3 années, a été marquée par l’émergence de l’Acinetobacter. La surveillance de la multi résistance bactérienne est une nécessité en milieu de réanimation pourvoyeur d’infections nosocomiales

Irminger Sea is the center of action for subpolar AMOC variability

Significant societally important climate impacts can be caused by changes in the strength of the Atlantic Meridional Overturning Circulation (AMOC) at higher latitudes. Focusing on variability and long-term change of the subpolar North Atlantic (SPNA)—a key AMOC action center—and using eastern OSNAP array observations, we identify a distinct density and sea-surface height signature of the AMOC strength in the Irminger Sea (2014–2018), reinforced and extended with an ocean reanalysis (1993–2018). Reconstruction of AMOC variability using Irminger Sea density shows strong control by the North Atlantic Oscillation on subpolar overturning on multiple timescales, achieved via the gyre circulation and waters from the Labrador Sea. Furthermore, the observed decrease of Irminger Sea density since the mid-twentieth century (1950–2019) is suggestive of a long-term AMOC weakening of 2.2 Sv or 13%, however, this trend remains statistically insignificant due to the large interannual and decadal variability of the SPNA

Brane inflation and the fine-tuning problem

Brane inflation can provide a promissing framework for solving the fine-tuning problem in standard inflationary models. The aim of this paper is to illustrate the mechanism by which this can be achieved. By considering the supersymmetric two-stage inflation model it is shown that the initial fine-tuning of the coupling parameter can be considerably relaxed. SubPlanckian values of the inflaton during inflation can also be obtained.Comment: 04 pages (Revtex

The Irminger Gyre as a key driver of the subpolar North Atlantic overturning

The lower limb of the Atlantic meridional overturning circulation (AMOC) is the equatorward flow of dense waters formed through the cooling and freshening of the poleward-flowing upper limb. In the subpolar North Atlantic (SPNA), upper limb variability is primarily set by the North Atlantic Current, whereas lower limb variability is less well understood. Using observations from a SPNA mooring array, we show that variability of the AMOC's lower limb is connected to poleward flow in the interior Irminger Sea. We identify this poleward flow as the northward branch of the Irminger Gyre (IG), accounting for 55% of the AMOC's lower limb variability. Over 2014–2018, wind stress curl fluctuations over the Labrador and Irminger Seas drive this IG and AMOC variability. On longer (>annual) timescales, however, an increasing trend in the thickness of intermediate water, from 2014 to 2020, within the Irminger Sea coincides with a decreasing trend in IG strength

Perceptions and Practices of Stimulating Children’s Cognitive Development Among Moroccan Immigrant Mothers

We explored the perceptions of children’s cognitive development among Moroccan Arabic and Berber immigrant mothers who cannot read, who are less educated, middle educated or highly educated in the Netherlands. A series of in-depth interviews was conducted with 22 mothers with young children (mean age = 5 years and 6 months). Qualitative data analyses revealed five major themes that are of significant importance to these mothers: moral attitudes, social values and religiousness; conversation, reading and playing as stimulating activities; importance attached to education; parental expectations; attributions of school success. The parental perceptions about the cognitive development of young children differed according to their own educational level. Mothers who cannot read and mothers with less education emphasized the development of moral, social and religious values for strengthening the cultural identity of their children. This sense of identity would enable them to function within their own cultural group and help them to perform well at school. School success was attributed in large part to a combination of the efforts of the child and the school. Middle and highly educated mothers, on the other hand, valued scholastic development and attributed school success to their own efforts and to the kind of support the child received. The ethnic background of the parents, whether Arabic or Berber, did not make a difference in the perceptions