What can hydrography tell Us about the strength of the Nordic Seas MOC over the last 70 to 100 years?

The flow of warm water into the Nordic Seas plays an important role for the mild climate of central and northern Europe. Here we estimate the stability of this flow thanks to the extensive hydrographic record that dates back to the early 1900s. Using all casts in two areas with little mean flow just south and north of the Greenland‐Scotland Ridge that bracket the two main inflow branches, we find a well‐defined approximately ±0.5 Sv volume transport (and a corresponding ±30 TW heat flux) variation in synchrony with the Atlantic multidecadal variability that peaked most recently around 2010 and is now trending down. No evidence is found for a long‐term trend in transport over the last 70 to 100 years

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

Effect of morphology and hydrophobization of MoS2 microparticles on the stability of poly-α-olefins lubricants

International audienceThe use of MoS ⁠ 2 nanoparticles as additive to lubricating oils is restricted by their low stability in oily media, which limits their use despite the enormous benefits associated with their intrinsic properties in terms of reduction of friction and wear coefficients. In this context, we investigated the effect of morphologies (platelets vs spheres) and surface functionalization of nanoparticles on the stability of their suspensions in poly-α-olefins (PAO) with various viscosities, which are base oils used in wind turbines. The particles were characterized by XRD, FTIR, scanning electron microscopy, atomic force microscopy and dynamic light scattering, and the stability of the resultant formulations was followed by optical (non-contact) measurements. It was found that the dispersions had similar stability despite the larger size of platelet-like particles compared to spherical ones (1-5 μm vs 600-800 nm). The dispersibility could be increased through grafting of alkylsilane on the surface defects (the longer the alkyl chain, the more stable the formulation) and with the increase of the oil kinematic viscosity (from 34 to 1705 cps at 25 °C)

North Atlantic subpolar gyre along predetermined ship tracks since 1993: a monthly data set of surface temperature, salinity, and density

We present a binned product of sea surface temperature, sea surface salinity, and sea surface density data in the North Atlantic subpolar gyre from 1993 to 2017 that resolves seasonal variability along specific ship routes (https://doi.org/10.6096/SSS-BIN-NASG). The characteristics of this product are described and validated through comparisons to other monthly products. Data presented in this work were collected in regions crossed by two predetermined ship transects, between Denmark and western Greenland (AX01) and between Iceland, Newfoundland, and the northeastern USA (AX02). The data were binned along a selected usable transect. The analysis and the strong correlation between successive seasons indicate that in large parts of the subpolar gyre, the binning approach is robust and resolves the seasonal timescales, in particular after 1997 and in regions away from the continental shelf. Prior to 2002, there was no winter sampling over the West Greenland Shelf. Variability in sea surface salinity increases towards Newfoundland south of 54°&thinsp;N, as well as in the western Iceland Basin along 59°&thinsp;N. Variability in sea surface temperature presents less spatial structure with an increase westward and towards Newfoundland. The contribution of temperature variability to density dominates in the eastern part of the gyre, whereas the contribution of salinity variability dominates in the southwestern part along AX02.</p

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

A Framework for the Development, Design and Implementation of a Sustained Arctic Ocean Observing System

Rapid Arctic warming drives profound change in the marine environment that have significant socio-economic impacts within the Arctic and beyond, including climate and weather hazards, food security, transportation, infrastructure planning and resource extraction. These concerns drive efforts to understand and predict Arctic environmental change and motivate development of an Arctic Region Component of the Global Ocean Observing System (ARCGOOS) capable of collecting the broad, sustained observations needed to support these endeavors. This paper provides a roadmap for establishing the ARCGOOS. ARCGOOS development must be underpinned by a broadly-endorsed framework grounded in high-level policy drivers and the scientific and operational objectives that stem from them. This should be guided by a transparent, internationally accepted governance structure with recognized authority and organizational relationships with the national agencies that ultimately execute network plans. A governance model for ARCGOOS must guide selection of objectives, assess performance and fitness-to-purpose, and advocate for resources. A requirements-based framework for an ARCGOOS begins with the Societal Benefit Areas (SBAs) that underpin the system. SBAs motivate investments and define the system's science and operational objectives. Objectives can then be used to identify key observables and their scope. The domains of planning/policy, strategy, and tactics define scope ranging from decades and basins to focused observing with near real time data delivery. Patterns emerge when this analysis is integrated across an appropriate set of SBAs and science/operational objectives, identifying impactful variables and the scope of the measurements. When weighted for technological readiness and logistical feasibility, this can be used to select Essential ARCGOOS Variables, analogous to Essential Ocean Variables of the Global Ocean Observing System. The Arctic presents distinct needs and challenges, demanding novel observing strategies. Cost, traceability and ability to integrate region-specific knowledge have to be balanced, in an approach that builds on existing and new observing infrastructure. ARCGOOS should benefit from established data infrastructures following the Findable, Accessible, Interoperable, Reuseable Principles to ensure preservation and sharing of data and derived products. Linking to the Sustaining Arctic Observing Networks (SAON) process and involving Arctic stakeholders, for example through liaison with the International Arctic Science Committee (IASC), can help ensure success

Rāšid et les Idrissides: l’histoire “originelle” du Maroc entre marginalisation et glorification

The dynasty of Idrisids is considered as the first of Morocco’s Islamic history. Nevertheless only the two figures of Idrīs I and Idrīs II are known by the general public and take up the specialists’ attentions. The character of Rāšid is completely left apart by the researchers. And yet he is the one who led future Idrīs I from Mecca to Volubilis, the one who succeeded him as head of the state and who had governed the country for twelve years (three times longer than Idrīs), and finally the one who minted coins with his name. I recently deal with this question in another article: the coins are from Volubilis, but also from the capital of the Rustumides, Tāhirt, that Rāšid certainly conquered. Moreover, he could have founded Fez for the first coins are minted in the city during his regency. All of this leads us to believe that this mysterious figure has played an important role and deserves a bigger place in the history books than he has today.[fr] Si les Idrissides sont aujourd’hui considérés comme la dynastie fondatrice de l’histoire musulmane du Maroc, seules les deux figures d’Idrīs I et d’Idrīs II monopolisent l’attention du grand public marocain (voire des spécialistes également). La figure de Rāšid est totalement marginalisée. Pourtant, c’est ce dernier qui conduisit le futur Idris I jusqu’à Volubilis (depuis La Mecque en passant notamment par l’Egypte), qui lui succéda au pouvoir pour régner presque trois fois plus longtemps que lui (environ douze années), qui frappa des monnaies à son nom (ainsi que l’a démontré une récente publication scientifique) aussi bien dans la capitale des Rustumides Tāhirt qu’il devait donc avoir temporairement conquise que dans la sienne Volubilis. La logique historique convainc mème du fait qu’il ait fondé Fès, vu que les plus anciennes monnaies (anonymes) frappées dans cette ville le furent sous son règne/régence… Autant de points qui méritent donc que l’on s’intéresse de plus près à cette figure mystérieuse qui pourrait bel et bien avoir eu un rôle de loin plus important que celui auquel l’a “cantonn” l’historiographie traditionnelle