Detritic deposits of periglacial origin under coluvial organic soil on a slope in Serra da Loba. (Galicia. Spain): characterization and genesis

[Resumen] En ciertas posiciones de las partes media e inferior de la ladera aparece bajo el suelo orgánico un material detrítico muy fragmentado y ordenado en lechos estratificados. Se estudian dos perfiles con estas características, se canografía su extensión en la ladera, y se interpreta su génesis. Estos derrubios tienen poca fracci6n fina entre ellos, son bastante frescos, yaparecen ordenados según la pendiente y dispuestos en lechos en los que se alternan fragmentos de pequeño tamaño con otros más gruesos con más escaso contenido en fracción fina. Los estudios morfológicos y granulométricos revelan claras discontinuidades en los perfiles, así como una baja clasificaci6n de este material detrítico. La composición mineralógica es menos reveladora por su escasa evolución, prácticamente la heredada del material de partida, con predominio de minerales poco alterables. Se hace una correspondencia estratigráfica de episodios de deposici6n en ambos perfiles y se interpreta el origen de este material detrítico como ligado al accionamiento periglaciar. La localizaci6n en la ladera de estos depósitos y su potencia están relacionados con el menor espesor de las líneas de piedras, indicativas de procesos de erosión posterior. Sin embargo estos depósitos están ausentes en las partes más bajas de la ladera que, en cambio, muestran ser las más propicias a la deposición, ya que presentan un mayor engrosamiento de los horizontes orgánicos de acumulaci6n y en ellas no aparecen indicios erosivos. Esta ausencia se interpreta por ser también estas zonas, bajas y abrigadas, las que podrían ser más favorables a una mayor cobertura vegetal en las condiciones periglaciares, que impediría la deposición de los derrubios.[Abstract] Stratified beds of highly fragmented detritic material under organic soil occur on medium and low parts ofthe slope. Two profiles with these features are studied, their extent on the slope is mapped and their genesis interpreted. Debris are quite fresh, with little fine fraction between them; they are arranged according to the slope and consist of alternating beds of little size fragments and others coarser and poor in fine fraction. Morphological and granulometric studies reveal clear discontinuities in the profiles and a poor soning of the detritic Ínaterials. Mineralogical composition is less meaningful because of its little evolution, almost inherited from parent material, with a predominance of hardly weatherable minerals. A stratigraphic correspondence is established of deposition episodes between both profiles, and the origin of the detritic material is related to periglacial dynamics. The position of these deposits on the slope and their thickness are inversely related to the thickness of stonelines which are indicative of subsequent erosive processes. Detritic deposits are absent in the lowest part of the slope, which on the other hand appear to be the most favourable to deposition as showed by the greatest thickness of organic horizons of accumulation, and the no occurrence of erosive signs. This absence is' interpreted as being caused by the presence of a more extensive vegetal cover, under periglacial conditions, in the lowest and more protected slope, so preventing debris deposition

Critical state theory for nonparallel flux line lattices in type-II superconductors

Coarse-grained flux density profiles in type-II superconductors with non-parallel vortex configurations are obtained by a proposed phenomenological least action principle. We introduce a functional $C[H(x)]$, which is minimized under a constraint of the kind $J$ belongs to $Delta$ for the current density vector, where $Delta$ is a bounded set. This generalizes the concept of critical current density introduced by C. P. Bean for parallel vortex configurations. In particular, we choose the isotropic case ($Delta$ is a circle), for which the field penetration profiles $H(x,t)$ are derived when a changing external excitation is applied. Faraday's law, and the principle of minimum entropy production rate for stationary thermodynamic processes dictate the evolution of the system. Calculations based on the model can reproduce the physical phenomena of flux transport and consumption, and the striking effect of magnetization collapse in crossed field measurements.Comment: The compiled TeX document length is 10 pages. Two figures (one page each) are also included The paper is accepted for publication in Phys. Rev. Let

In vivo chromatin targets of the transcription factor Yin Yang 2 in trophoblast stem cells

Background: Yin Yang 2 (YY2) is a zinc finger protein closely related to the well-characterized Yin Yang 1 (YY1). YY1 is a DNA-binding transcription factor, with defined functions in multiple developmental processes, such as implantation, cell differentiation, X inactivation, imprinting and organogenesis. Yy2 has been treated as a largely immaterial duplication of Yy1, as they share high homology in the Zinc Finger-region and similar if not identical in vitro binding sites. In contrast to these similarities, gene expression alterations in HeLa cells with attenuated levels of either Yy1 or Yy2 were to some extent gene-specific. Moreover, the chromatin binding sites for YY2, except for its association with transposable retroviral elements (RE) and Endogenous Retroviral Elements (ERVs), remain to be identified. As a first step towards defining potential Yy2 functions matching or complementary to Yy1, we considered in vivo DNA binding sites of YY2 in trophoblast stem (TS) cells. Results: We report the presence of YY2 protein in mouse-derived embryonic stem (ES) and TS cell lines. Following up on our previous report on ERV binding by YY2 in TS cells, we investigated the tissue-specificity of REX1 and YY2 binding and confirm binding to RE/ERV targets in both ES cells and TS cells. Because of the higher levels of expression, we chose TS cells to understand the role of Yy2 in gene and chromatin regulation. We used in vivo YY2 association as a measure to identify potential target genes. Sequencing of chromatin obtained in chromatin-immunoprecipitation (ChIP) assays carried out with aYY2 serum allowed us to identify a limited number of chromatin targets for YY2. Some putative binding sites were validated in regular ChIP assays and gene expression of genes nearby was altered in the absence of Yy2. Conclusions: YY2 binding to ERVs is not confined to TS cells. In vivo binding sites share the presence of a consensus binding motif. Selected sites were uniquely bound by YY2 as opposed to YY1, suggesting that YY2 exerts unique contributions to gene regulation. YY2 binding was not generally associated with gene promoters. However, several YY2 binding sites are linked to long noncoding RNA (lncRNA) genes and we show that the expression levels of a few of those are Yy2-dependent

Evaluation of the combined glucose-insulin and intravenous glucose tolerance tests for insulin dysregulation diagnosis in donkeys

Background. Insulin dysregulation (ID) and donkey metabolic syndrome (DMS) are common in this species. Contrary to horses, diagnostic guidelines compiling insulin cut-offs values and dynamic testing interpretations have not been reported for this species. Objectives. To evaluate resting serum insulin concentrations, the combined glucose-insulin test (CGIT) and the glucose intravenous tolerance test (IVGTT) for the diagnosis of DMS with ID suspicion. Study design. Diagnostic test comparison.Methods. Six of 80 mix-breed adult donkeys fulfilled the inclusion criteria for DMS based on history or clinical evidence of recurrent laminitis, body condition >6 and neck score >2 or baseline insulin and leptin concentrations >20 µIU/mL and >12 ng/mL respectively. CGIT and IVGTT were performed in all donkeys within a week and interpreted following guidelines reported for equine metabolic syndrome (EMS). Insulin and glucose curves were analysed, proxies calculated and correlations and multivariate analysis assessed. Results. Following EMS guidelines, CGIT classified 2 (using glucose-positive phase duration) or 3 (using insulin concentration) and IVGTT classified 5 donkeys as ID. ID donkeys showed a lower glucose/insulin ratio, QUICKI and RISQI, and a higher insulin/glucose ratio, MIRG and HOMA-B%. Main limitations. Comparison of these tests with additional dynamic testing including a larger number of ID donkeys is necessary. Conclusions. This is the first study evaluating dynamic tests to assess ID/DMS in DMS-suspected donkeys. IVGTT detected more ID donkeys than CGIT. EMS recommendations could also be used for DMS diagnosis, although a baseline insulin cut-off value is needed

Enhancement of resistivity and magnetization of Bi1-xLaxFe1-yMnyO3 ceramics by composition optimization

This work aims at studying the effect of La and Mn substituents on the structural, electrical and magnetic properties of Bi1-xLaxFe1-yMnyO3 (0≤x≤0.30; 0≤y≤0.20) at room temperature, in order to find out the optimal compositions that provide both high resistivity and remnant magnetization. The analysis of the XRD patterns and Raman spectra suggest a progressive transition from a rhombohedral for x0.20. Moreover, we observe satellite peaks associated with an incommensurate modulated (IM) orthorhombic structure for x≥0.15 with y = 0, and x = 0.20 with y = 0.10. We were able to achieve a decrease by several orders of magnitude of the leakage current density and the emergence of a weak ferromagnetic response in the range of compositions 0.10<x≤0.3 and 0<y<0.1. These improved physical properties are a consequence of the absence of secondary phases and the breaking of the spiral cycloid spin structure. In particular, the compositions within 0.18≤x≤0.30 and 0.01<y<0.05 with IM orthorhombic structure exhibit the lowest conductivity and highest remnant magnetization. The outcome of this work suggests an alternative route to enhance multiferroic properties of BiFeO3, with simultaneous La (0.10≤x≤0.30) and moderate Mn (0.01<y<0.1) substitution.publishe

Marine collagen/apatite composite scaffolds envisaging hard tissue applications

The high prevalence of bone defects has become a worldwide problem. Despite the significant amount of research on the subject, the available therapeutic solutions lack efficiency.  Autografts, the most common used approaches to treat bone defects have limitations such as donor site morbidity, pain and lack of donor site. Marine resources emerge as an attractive alternative to extract bioactive compounds for further use in bone tissue engineering approaches. On one hand they can be isolated from by-products, at low costs, creating value from products that are considered waste for the fish transformation industry. One the other hand, religious constraints will be avoided. We isolated two marine origin materials, collagen from shark skin (Prionace glauca) and calcium phosphates from teeth of two different shark species (Prionace glauca and Isurus oxyrinchus), and further proposed to mix them to produce 3D composite structures for hard tissue applications. Two crosslinking agents, EDC/NHS and HMDI, were tested to enhance scaffoldsâ properties, with EDC/NHS resulting in better properties. The characterization of the structures showed that the developed composites could support attachment and proliferation of osteoblast-like cells. A promising scaffold for the engineering of bone tissue is thus proposed, based on a strategy of marine by-products valorisation.This work was funded by INTERREG under the POCTEP Project 0687_NOVOMAR_1_P and the Atlantic Area Transnational Cooperation Programme Project MARMED (2011-1/164), as well as by European Union FP7 under the project POLARIS (REGPOT-CT2012-316331).info:eu-repo/semantics/publishedVersio

Population overlap and habitat segregation in wintering Black-tailed Godwits Limosa limosa

Distinct breeding populations of migratory species may overlap both spatially and temporally, but differ in patterns of habitat use. This has important implications for population monitoring and conservation. To quantify the extent to which two distinct breeding populations of a migratory shorebird, the Black-tailed Godwit Limosa limosa, overlap spatially, temporally and in their use of different habitats during winter. We use mid-winter counts between 1990 and 2001 to identify the most important sites in Iberia for Black-tailed Godwits. Monthly surveys of estuarine mudflats and rice-fields at one major site, the Tejo estuary in Portugal in 2005-2007, together with detailed tracking of colour-ringed individuals, are used to explore patterns of habitat use and segregation of the Icelandic subspecies L. l. islandica and the nominate continental subspecies L. l. limosa. In the period 1990-2001, over 66 000 Black-tailed Godwits were counted on average in Iberia during mid-winter (January), of which 80% occurred at just four sites: Tejo and Sado lower basins in Portugal, and Coto Dontildeana and Ebro Delta in Spain. Icelandic Black-tailed Godwits are present throughout the winter and forage primarily in estuarine habitats. Continental Black-tailed Godwits are present from December to March and primarily use rice-fields. Iberia supports about 30% of the Icelandic population in winter and most of the continental population during spring passage. While the Icelandic population is currently increasing, the continental population is declining rapidly. Although the estuarine habitats used by Icelandic godwits are largely protected as Natura 2000 sites, the habitat segregation means that conservation actions for the decreasing numbers of continental godwits should focus on protection of rice-fields and re-establishment of freshwater wetlands

Clave dicotómica para la identificación preliminar de las especies de "Gambierdiscus" y "Fukuyoa" reportadas en la región del Caribe

Los géneros de dinoflagelados bentónicos Gambierdiscus y Fukuyoa están entre los agentes causales de la ciguatera, intoxicación causada por el consumo de invertebrados y peces contaminados con ciguatoxinas. Debido a las similitudes morfológicas que presentan las especies pertenecientes a estos géneros, su identificación requiere del uso combinado de técnicas de microscopía y moleculares. Sin embargo, estas metodologías son poco accesibles para muchos países con limitados recursos económicos, donde lo más común es disponer en la práctica de la microscopía óptica. Este trabajo propone una clave dicotómica para la identificación preliminar de las especies de Gambierdiscus y Fukuyoa reportadas en la región del Caribe, utilizando caracteres morfológicos visibles al microscopio óptico convencional. La clave propuesta permite emplear un número limitado de caracteres morfológicos lo cual fue posible al incluir pocas especies en el análisis.   Recibido: 15.09.2022 Aceptado: 06.06.2023 Editor: Liliana Gómez Lun

Charge separation relative to the reaction plane in Pb-Pb collisions at sNN=2.76\sqrt{s_{\rm NN}}= 2.76 TeV

Measurements of charge dependent azimuthal correlations with the ALICE detector at the LHC are reported for Pb-Pb collisions at $\sqrt{s_{\rm NN}} = 2.76$ TeV. Two- and three-particle charge-dependent azimuthal correlations in the pseudo-rapidity range $|\eta| < 0.8$ are presented as a function of the collision centrality, particle separation in pseudo-rapidity, and transverse momentum. A clear signal compatible with a charge-dependent separation relative to the reaction plane is observed, which shows little or no collision energy dependence when compared to measurements at RHIC energies. This provides a new insight for understanding the nature of the charge dependent azimuthal correlations observed at RHIC and LHC energies.Comment: 12 pages, 3 captioned figures, authors from page 2 to 6, published version, figures at http://aliceinfo.cern.ch/ArtSubmission/node/286