A key life-history component for many animals is the need for movement between different geographical locations at particular times. Green turtle (Chelonia mydas) hatchlings disperse from their natal ...location to spend an early pelagic stage in the ocean, followed by a neritic stage where small juveniles settle in coastal areas. In this study, we combined genetic and Lagrangian drifter data to investigate the connectivity between natal and foraging locations. In particular we focus on the evidence for transatlantic transport. Atlantic Ocean. We used mitochondrial DNA (mtDNA) sequences (n = 1567) from foraging groups (n = 8) and nesting populations (n = 12) on both sides of the Atlantic. Genetic data were obtained for Cape Verde juvenile turtles, a foraging group not previously sampled for genetic study. Various statistical methods were used to explore spatial genetics and population genetic structure (e.g. exact tests of differentiation, G eneland and analysis of molecular variance). Many-to-many mixed stock analysis estimated the connectivity between nesting and foraging groups. Our key new finding is robust evidence for connectivity between a nesting population on the South American coast (25% of the Surinam nesting population are estimated to go to Cape Verde) and a foraging group off the coast of West Africa (38% of Cape Verde juveniles are estimated to originate from Surinam), thus extending the results of previous investigations by confirming that there is substantial transatlantic dispersal in both directions. Lagrangian drifter data demonstrated that transport by drift across the Atlantic within a few years is possible. Small juvenile green turtles seem capable of dispersing extensively, and can drop out of the pelagic phase on a transatlantic scale (the average distance between natal and foraging locations was 3048 km). Nevertheless, we also find support for the 'closest-to-home' hypothesis in that the degree of contribution from a nesting population to a foraging group is correlated with proximity. Larger-sized turtles appear to feed closer to their natal breeding grounds (the average distance was 1133 km), indicating that those that have been initially transported to far-flung foraging grounds may still be able to move nearer to home as they grow larger.
For many species, there is broad-scale dispersal of juvenile stages and/or long-distance migration of individuals and hence the processes that drive these various wide-ranging movements have ...important life-history consequences. Sea turtles are one of these paradigmatic long-distance travellers, with hatchlings thought to be dispersed by ocean currents and adults often shuttling between distant breeding and foraging grounds. Here, we use multi-disciplinary oceanographic, atmospheric and genetic mixed stock analyses to show that juvenile turtles are encountered ‘downstream’ at sites predicted by currents. However, in some cases, unusual occurrences of juveniles are more readily explained by storm events and we show that juvenile turtles may be displaced thousands of kilometres from their expected dispersal based on prevailing ocean currents. As such, storms may be a route by which unexpected areas are encountered by juveniles which may in turn shape adult migrations. Increased stormy weather predicted under climate change scenarios suggests an increasing role of storms in dispersal of sea turtles and other marine groups with life-stages near the ocean surface.
The relationship between invaders and the pathogens encountered in their new environment can have a large effect on invasion success. Invaders can become free from their natural pathogens and ...reallocate costly immune resources to growth and reproduction, thereby increasing invasion success. Release from enemies and relaxation of selective pressures could render newly founded populations more variable at immune-related genes, such as the major histocompatibility complex (MHC), particularly when they have different origins. Using rainbow and brown trout, two of the world’s most successful fish invaders, we tested the general hypothesis that invaders should display high intrapopulation immunogenetic diversity and interpopulation divergence, due to the interplay between genetic drift and successive waves of genetically divergent introductions. We analysed genetic diversity and signatures of selection at the MHC class II β immune-related locus. In both species, MHC diversity (allelic richness and heterozygosity) for southern hemisphere populations was similar to values reported for populations at their native range. However, MHC functional diversity was limited, and population immunogenetic structuring weaker than that observed using neutral markers. Depleted MHC functional diversity could reflect a decrease in immune response, immune-related assortative mating or selection for resistance to newly encountered parasites. Given that the role of MHC diversity in the survival of these populations remains unclear, depleted functional diversity of invasive salmonids could compromise their long-term persistence. A better understanding of the eco-immunology of invaders may help in managing and preventing the impact of biological invasions, a major cause of loss of biodiversity worldwide.
We have studied the magnetism in superconducting single crystals of EuFe2As1.4P0.6 by using the local probe techniques of zero-field muon spin rotation/relaxation and 151Eu/57Fe Mössbauer ...spectroscopy. All of these measurements reveal magnetic hyperfine fields below the magnetic ordering temperature TM=18K of the Eu2+ moments. The analysis of the data shows that there is a coexistence of antiferromagnetism, resulting from Eu2+ moments ordered along the crystallographic c-axis, and superconductivity below TSC≈ 10K. We find indications for a change in the dynamics of the small Fe magnetic moments (~0.07 μB) at T⁎≃15K that may be triggering the onset of superconductivity: below T⁎ the Fe magnetic moments seem to be “frozen” within the ab-plane.
•Coexistence of superconductivity and magnetism.•Study of magnetism using 3 different local techniques.•Change at Fe magnetic moment dynamics below superconducting transition temperature.
The hawksbill turtle is a critically endangered species that has been extensively exploited for centuries. Príncipe Island off western Africa harbours one of the species' major nesting populations in ...the eastern Atlantic, as well as hosting year-round foraging aggregations of juveniles, subadults and adult males. To gain insight into the population's genetic structure and relationships with regional stocks, we analysed mitochondrial DNA (mtDNA) sequences of nesting females (N=9), foraging adult females (N=11), adult males (N=32), subadults (N=15) and juveniles (N=80). The nesting population was found to be fixed for a single haplotype (EATL), which had been previously reported in both western and eastern Atlantic hawksbill foraging sites but had no known rookery source prior to this study. Thus it is now possible to confirm the westward transoceanic movement by hawksbills originating from Príncipe Island. Our analyses demonstrated that the Príncipe Island nesting colony is genetically distinct from breeding populations in the western Atlantic and is phylogenetically linked with Indo-Pacific hawksbill clades, suggesting that Príncipe Island was most likely colonised by migrants from the Indian Ocean via the Cape of Good Hope in southern Africa. Mixed stock analyses revealed that the eastern Atlantic appears to be the primary foraging area for Príncipe hawksbills (75%) while most of the foraging juveniles in Príncipe waters originate from the Príncipe rookery (84%). Furthermore, the presence of Caribbean haplotypes at low frequencies (<5%) suggests that eastward transatlantic movements by juveniles to distant foraging and developmental habitats also take place. Depleted hawksbill populations in the eastern Atlantic combined with the low genetic variability and high genetic distinctiveness found in the Príncipe nesting and foraging aggregations with respect to the western Atlantic, underscore the high degree of isolation and vulnerability of this eastern Atlantic stock. These characteristics are highly relevant for the development of effective conservation programmes and highlight the urgent need to consolidate international cooperation across regional boundaries.
► First genetic characterization of a hawksbill rookery in the eastern Atlantic. ► The Príncipe rookery was found to be fixed for a single haplotype (EATL). ► The EATL haplopyte had no known rookery source prior to this study. ► This unique haplotype was phylogenetically linked with Indo-Pacific clades. ► Results revealed the high degree of isolation and fragility of this rookery.
El objetivo principal de este estudio es analizar el efecto que tiene la aplicación de un Programa de Intervención Artística sobre el estado de ánimo. Se analizan los efectos de la observación e ...identificación de recursos expresivos de movimiento y escucha musical, a través de un espectáculo de danza-circo con música en directo, así como la posible correlación entre dichas variables. Se llevó a cabo un estudio cuasi-experimental, pre-post intervención (N =15). Los resultados muestran una influencia positiva del Programa encontrándose una reducción significativa en los factores de tensión y fatiga del Profile of Mood States (POMS). Se exploran algunos componentes de la experiencia de apreciación y se discuten los efectos que podría tener sobre la salud física y emocional.
Urban territorial expansion generated in the last decades has brought a series of consequences, such as the variation between urban and suburban weather conditions affecting indoor temperature and ...increasing electricity consumption derived from the use of cooling systems. Current approaches of simulation models in residential buildings use indoor environmental data for carrying out validations to propose hygrothermal comfort alternatives for the mitigation of the effects of the external environmental conditions on the interior spaces of dwellings. In this work, an hourly evaluation of both indoor and outdoor environmental parameters of two case studies in a tropical climate was carried out, by means of a whole-building simulation approach tool during a week representative of the warmest period of the year. The integration of the collected environmental data in the theoretical model allowed us to reduce the error range of the estimated indoor temperature with results in normalized mean bias error between 7.10% and −0.74% and in coefficient of variation of the root mean square error between 16.72% and 2.62%, in the different indoor zones of the case studies. At the same time, the energy assessment showed a difference of 33% in Case 1 and −217% in Case 2 for final electricity consumption.
Superconductivity in the iron pnictides is often closely connected to a nematic state in which the tetragonal symmetry of the crystal is spontaneously broken. Determining the dominant interactions ...responsible for this symmetry breaking is essential to understanding the superconducting state. Here, we use atomic-resolution variable-temperature scanning tunnelling spectroscopy to probe the nanoscale electronic structure of the nematically ordered, parent pnictide NaFeAs and compare it with non-nematic LiFeAs. Local electronic nematicity is only manifest in NaFeAs and is found to persist to high temperatures in the nominally tetragonal phase of the crystal. The spatial distribution and energy dependence of the electronic anisotropy at high temperatures is explained by the persistence of large-amplitude, short-range, unidirectional, antiferroic fluctuations, indicating that strong density-wave fluctuations exist and couple to near-Fermi surface electrons even far from the structural and density-wave phase boundaries.
The purpose of this research is to provide an approximation to the likely effects of the impact of the most important transmission channels of the international economic crisis on the Colombian ...economy. It also assesses the effectiveness of the most significant components of policy response. For this, a static computable general equilibrium model (CGE) is used. The results obtained are interesting in their own right and are in line with what could be expected given the information available on the behavior of the Colombian economy. Furthermore, they call into question the effectiveness of governmental intervention as judged by its intended countercyclical effects. PUBLICATION ABSTRACT
In a prototypical ferromagnet (Ga,Mn)As based on a III-V semiconductor, substitution of divalent Mn atoms into trivalent Ga sites leads to severely limited chemical solubility and metastable ...specimens available only as thin films. The doping of hole carriers via (Ga,Mn) substitution also prohibits electron doping. To overcome these difficulties, Masek et al. theoretically proposed systems based on a I-II-V semiconductor LiZnAs, where isovalent (Zn,Mn) substitution is decoupled from carrier doping with excess/deficient Li concentrations. Here we show successful synthesis of Li(1+y)(Zn(1-x)Mn(x))As in bulk materials. Ferromagnetism with a critical temperature of up to 50 K is observed in nominally Li-excess (y=0.05-0.2) compounds with Mn concentrations of x=0.02-0.15, which have p-type metallic carriers. This is presumably due to excess Li in substitutional Zn sites. Semiconducting LiZnAs, ferromagnetic Li(Zn,Mn)As, antiferromagnetic LiMnAs, and superconducting LiFeAs systems share square lattice As layers, which may enable development of novel junction devices in the future.
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