Off-equilibrium fluctuation-dissipation relation in a spin glass

We report new experimental results obtained onthe insulating spin glass CdCrInS_4. Our experimental setup allows a quantitative comparison between thethermo-remanent magnetization and the autocorrelation of spontaneous fluctuations of magnetization, yielding acomplete determination of the fluctuation-dissipationrelation. The dynamics can be studied both in thequasi-equilibrium regime, where the fluctuation-dissipation theorem holds, and in the deeply aging regime. The limit of separation of time-scales, as used in analytical calculations, can be approached by use of a scaling procedure.Comment: Minor changes, accepted for publication in EPJ-

Topological phase transitions between chiral and helical spin textures in a lattice with spin-orbit coupling and a magnetic field

We consider the combined effects of large spin-orbit couplings and a perpendicular magnetic field in a 2D honeycomb fermionic lattice. This system provides an elegant setup to generate versatile spin textures propagating along the edge of a sample. The spin-orbit coupling is shown to induce topological phase transitions between a helical quantum spin Hall phase and a chiral spin-imbalanced quantum Hall state. Besides, we find that the spin orientation of a single topological edge state can be tuned by a Rashba spin-orbit coupling, opening an interesting route towards quantum spin manipulation. We discuss the possible realization of our results using cold atoms trapped in optical lattices, where large synthetic magnetic fields and spin-orbit couplings can be engineered and finely tuned. In particular, this system would lead to the observation of a time-reversal-symmetry-broken quantum spin Hall phase.Comment: 8 pages, 3 figures, Accepted in Europhys. Lett. (Dec 2011

Variabilidad espacial de los parámetros de historia vital del estornino (Scomber colias), una especie en expansión en el Atlántico noreste

Atlantic chub mackerel is a pelagic species present in the Atlantic Ocean that in recent decades has expanded northwards in the eastern Atlantic. Fish samples were collected in scientific surveys and commercial catches between 2011 and 2019. We analysed the geographical variation of the biological parameters (age, length, weight and condition), as well as the length-weight relationship, maturity-at-length and spawning season onset and duration in five geographical areas (from south to north): the Canary Islands, Gulf of Cadiz, western Portuguese coast, northwestern Spanish coast and Cantabrian Sea. The influence of sea surface temperature (SST) on fish length was modelled as a potential driver of geographical variability. All biological parameters increased progressively northwards, while the spawning season was delayed and prolonged with increasing latitude, from January in the Canary Islands to May-August in the Cantabrian Sea, when SST was between 15°C and 19°C. SST had a positive effect on length in three study areas and a negative one in two of them, suggesting that each group is at a different position within their thermal tolerance range. Deviance from the geographical pattern of some biological parameters in the Gulf of Cadiz suggests that it could be a hinge or mixing zone between Atlantic African, Mediterranean and Atlantic Iberian population components.El estornino es una especie pelágica presente en el océano Atlántico que en las últimas décadas se ha expandido hacia el norte en el Atlántico Oriental. Se recogieron muestras de peces procedentes de campañas científicas y capturas comerciales entre 2011 y 2019. Se analizó la variación geográfica de los parámetros biológicos (edad, longitud, peso y condición), así como la relación longitud-peso, la talla de madurez y el inicio y la duración de la temporada de desove en cinco áreas geográficas (de sur a norte): las islas Canarias, el Golfo de Cádiz, la costa occidental portuguesa, la costa noroccidental española y el mar Cantábrico. Se modeló la influencia de la SST en la talla de los peces como posible causa de la variabilidad geográfica. Todos los parámetros biológicos aumentaron progresivamente hacia el norte, mientras que la temporada de desove se retrasó y prolongó con el aumento de la latitud, desde enero en las islas Canarias hasta mayo-agosto en el mar Cantábrico, cuando la SST estaba entre 15ºC y 19ºC. La SST tuvo un efecto positivo sobre la talla en tres áreas de estudio y negativo en dos de ellas, lo que sugiere que cada grupo se encuentra en una posición diferente dentro de su rango de tolerancia térmica. La desviación del patrón geográfico de algunos parámetros biológicos en el Golfo de Cádiz, sugiere que podría ser una zona bisagra o de mezcla entre componentes poblacionales atlánticos africanos, mediterráneos e ibéricos

Psoriasis: from pathogenesis to pharmacological and nano-technological-based therapeutics

Research in the pathogenesis of inflammatory skin diseases, such as skin dermatitis and psoriasis, has experienced some relevant breakthroughs in recent years. The understanding of age-related factors, gender, and genetic predisposition of these multifactorial diseases has been instrumental for the development of new pharmacological and technological treatment approaches. In this review, we discuss the molecular mechanisms behind the pathological features of psoriasis, also addressing the currently available treatments and novel therapies that are under clinical trials. Innovative therapies developed over the last 10 years have been researched. In this area, advantages of nanotechnological approaches to provide an effective drug concentration in the disease site are highlighted, together with microneedles as innovative candidates for drug delivery systems in psoriasis and other inflammatory chronic skin diseases.This research was funded by the Portuguese Science and Technology Foundation (FCT/MCT) and European Funds (PRODER/COMPETE), under the project reference UIDB/04469/2020 (strategic fund), co-financed by FEDER, under the Partnership Agreement PT2020, granted to EBS.info:eu-repo/semantics/publishedVersio

Growth variability and demographic structure of northeast Atlantic chub mackerel (Scomber colias) in southern European Atlantic waters

The Atlantic chub mackerel (Scomber colias) is one of the main fishing resources for the fisheries targeting small pelagics in NW African waters. This species is expanding its geographical distribution through higher latitudes in southern European Atlantic waters, and it has become an important fishing resource in Iberian Atlantic waters during the last decades. The present study addresses the growth variability of S. colias in the Iberian waters, from southern Bay of Biscay up to Gulf of Cadiz. Age estimates based on otoliths and growth parameters were obtained from specimens collected within the study area during one decade (from both commercial landings and scientific-acoustic surveys), and sexual growth variation was analysed. A common pattern of abundant cohorts was observed in various areas. However, differences in the demographic structure of the catches were observed among the different areas, with the southernmost area studied (Portuguese and Spanish waters off Gulf of Cadiz) standing out with younger individuals. These new findings are of interest for the stock assessment of S. colias, which has not been addressed in ICES waters so far

Unveiling the collaborative effect at the cucurbit[8]urilMoS2 hybrid interface for electrochemical melatonin determination

Host-guest interactions are of paramount importance in supramolecular chemistry and in a wide range of applications. Particularly well known is the ability of cucurbit[n]urils (CB[n]) to selectively host small molecules. We show that the charge transfer and complexation capabilities of CB[n] are retained on the surface of 2D transition metal dichalcogenides (TMDs), allowing the development of efficient electrochemical sensing platforms. We unveil the mechanisms of host-guest recognition between the MoS2- CB[8] hybrid interface and melatonin (MLT), an important molecular regulator of vital constants in vertebrates. We find that CB[8] on MoS2 organizes the receptor portals perpendicularly to the surface, facilitating MLT complexation. This advantageous adsorption geometry is specific to TMDs and favours MLT electro-oxidation, as opposed to other 2D platforms like graphene, where one receptor portal is closed. This study rationalises the cooperative interaction in 2D hybrid systems to improve the efficiency and selectivity of electrochemical sensing platform

Simulating Dirac fermions with Abelian and non-Abelian gauge fields in optical lattices

In this work we present an optical lattice setup to realize a full Dirac Hamiltonian in 2+1 dimensions. We show how all possible external potentials coupled to the Dirac field can arise from perturbations of the existing couplings of the honeycomb lattice model, without the need of additional laser fields. This greatly simplifies the proposed implementations, requiring only spatial modulations of the intensity of the laser beams. We finally suggest several experiments to observe the properties of the Dirac field in the setup

A Quasi-Exclusive European Ancestry in the Senepol Tropical Cattle Breed Highlights the Importance of the slick Locus in Tropical Adaptation

Background: The Senepol cattle breed (SEN) was created in the early XXth century from a presumed cross between a European (EUT) breed (Red Poll) and a West African taurine (AFT) breed (N'Dama). Well adapted to tropical conditions, it is also believed trypanotolerant according to its putative AFT ancestry. However, such origins needed to be verified to define relevant husbandry practices and the genetic background underlying such adaptation needed to be characterized. Methodology/Principal Findings: We genotyped 153 SEN individuals on 47,365 SNPs and combined the resulting data with those available on 18 other populations representative of EUT, AFT and Zebu (ZEB) cattle. We found on average 89% EUT, 10.4% ZEB and 0.6% AFT ancestries in the SEN genome. We further looked for footprints of recent selection using standard tests based on the extent of haplotype homozygosity. We underlined i) three footprints on chromosome (BTA) 01, two of which are within or close to the polled locus underlying the absence of horns and ii) one footprint on BTA20 within the slick hair coat locus, involved in thermotolerance. Annotation of these regions allowed us to propose three candidate genes to explain the observed signals (TIAM1, GRIK1 and RAI14). Conclusions/Significance: Our results do not support the accepted concept about the AFT origin of SEN breed. Initial AFT ancestry (if any) might have been counter-selected in early generations due to breeding objectives oriented in particular toward meat production and hornless phenotype. Therefore, SEN animals are likely susceptible to African trypanosomes which questions the importation of SEN within the West African tsetse belt, as promoted by some breeding societies. Besides, our results revealed that SEN breed is predominantly a EUT breed well adapted to tropical conditions and confirmed the importance in thermotolerance of the slick locus. (Résumé d'auteur