142 research outputs found
Social and environmental components of nestling provisioning behaviour in cooperatively breeding carrion crows
93 p.[ES] La cría cooperativa en aves se produce cuando unos individuos llamados ayudantes renuncian o posponen su propia reproducción para colaborar en el cuidado de las crías que no son suyas. La explicación más contundente y contrastada a este fenómeno es la obtención de beneficios indirectos como explica la selección por parentesco de Hamilton. Sin embargo, existen sociedades cooperativas donde el grado de parentesco entre los individuos es muy bajo o incluso inexistente. Además, en algunas especies que viven en grupos familiares, los beneficios indirectos parecen ser insuficientes para explicar un retraso en la reproducción propia. Por ello, se ha hipotetizado la existencia de beneficios directos (acceso a los recursos, protección frente a los depredadores y aumento del estatus social, entre otros) que permitan a estas sociedades mantenerse en el tiempo. Hay que destacar que la obtención de alguno de estos beneficios implica que los ayudantes señalen su contribución a otros individuos del grupo social. Sin embargo, la mayoría de los estudios hasta el momento, se han centrado únicamente en la cantidad del cuidado parental que proporciona cada miembro del grupo a la descendencia, pasando por alto la distribución temporal de las contribuciones individuales, siendo esta nueva dimensión la que podrá desvelar aspectos sociales del comportamiento cooperativo hasta ahora desconocidos, relacionados con su función última y con su mecanismo. En primer lugar, observar los patrones de solapamiento en el nido entre los diferentes miembros del grupo podría revelar si el aprovisionamiento de las crías mantiene un componente de señalización entre los cuidadores, con el fin de obtener beneficios directos, como, por ejemplo, un mayor “prestigio social” o el acceso a los recursos del territorio mediante “pago de una renta”. En segundo lugar, modelos teóricos recientes han postulado que una toma de turnos en las visitas al nido podría minimizar el conflicto sobre la distribución del cuidado parental. Testar estos dos aspectos en la sociedad cooperativa de la corneja negra Corvus corone, son dos objetivos clave de esta tesis, abordar los beneficios directos y la función señal nos permitirá arrojar luz sobre la función última de la cooperación, e investigar la estrategia de toma de turnos, nos ayudará a comprender los mecanismos estabilizadores de la cooperación en este sistema.
La corneja negra forma familias extendidas en el norte de España, donde los hijos retenidos y los parientes lejanos ayudan a la pareja reproductora dominante a criar a su prole. En esta sociedad, la probabilidad de reproducción futura de los machos subordinados es baja, por lo que permanecer en el grupo y aumentar su eficacia biológica indirecta se hace la mejor de las opciones. Sin embargo, las hembras subordinadas encuentran más fácilmente las condiciones favorables para abandonar el territorio con el propósito de reproducirse y aumentar su eficacia biológica directa. Esta perspectiva futura desigual entre machos y hembras ayudantes se ve también reflejada en sus contribuciones al nido, siendo la aportación de los machos significativamente mayor que la de las hembras. En estas circunstancias se espera que los dominantes, que a su vez sufren costes por mantener a los subordinados, vigilen más la contribución al nido de las hembras subordinadas. Y éstas, podrían necesitar hacer más visible su contribución para garantizar su permanencia al grupo. De acuerdo con esta idea, encontramos que las hembras ayudantes se solaparon más con los dominantes que cualquier otra categoría. Además, su permanencia en el grupo se asoció con un mayor esfuerzo, percibido por los dominantes, en la alimentación de los pollos. Nuestros resultados son coherentes con la hipótesis de” pagar por quedarse” y sugieren que puede surgir un componente de señalización de la ayuda en una sociedad cooperativa típicamente basada en el parentesco.
El aprovisionamiento cooperativo al nido puede producirse como resultado de una mera suma de los esfuerzos individuales de múltiples cuidadores que actúan de forma independiente, pero estudios recientes sugieren que los individuos también pueden coordinarse de manera activa adoptando una estrategia por turnos. Sin embargo, la evidencia de que los individuos responden al comportamiento de los demás es controvertida, y se desconocen los beneficios potenciales de dicha coordinación. Nuestros resultados muestran que todos los miembros del grupo de la corneja negra alternaban sus visitas en el aprovisionamiento de los pollos. Además, la masa corporal de los pollos aumentó significativamente con el grado de alternancia de los cuidadores, posiblemente porque los grupos coordinados proporcionaban alimento a intervalos más regulares. El aumento de la masa corporal de los pollos volanderos, en la corneja negra, se traduce en una mayor supervivencia después de abandonar el nido. Nuestro estudio, por lo tanto, demuestra que la alternancia en la provisión de alimento a los pollos tiene beneficios en términos de fitness, medibles en términos de supervivencia de los pollos. Esto implica que cualquier mecanismo que provoque y/o mejore la alternancia al nido sería favorecido por la selección natural.
Sin embargo, no solo los factores intrínsecos y sociales determinan los cuidados parentales en las aves que crían cooperativamente, sino que los efectos de los factores ambientales (tales como las variables meteorológicas) también pueden jugar un papel relevante en este sentido. Las condiciones meteorológicas (como, por ejemplo, la temperatura y la sequía) pueden limitar el aprovisionamiento de las crías en algunas especies de aves, pero las consecuencias sobre el éxito reproductor están aún pobremente estudiadas. El tercer objetivo de esta tesis aborda esta cuestión en la sociedad cooperativa de la corneja negra, mediante el análisis de un conjunto de datos a largo plazo que comprende los últimos 26 años. Nuestros resultados mostraron que la frecuencia de cebas individual disminuyó significativamente con el aumento de las temperaturas para todas las categorías sociales, mientras que la sequía se asoció con una reducción significativa del esfuerzo de los machos ayudantes en comparación con otras categorías sociales. El grado de alternancia de los cuidadores en las visitas al nido también se vio afectado negativamente por el aumento de la temperatura. Se detectaron consecuencias sobre el éxito reproductor de las cornejas en términos de condición corporal de los pollos, que empeoró cuando las temperaturas fueron altas durante el periodo de desarrollo de los pollos. Finalmente, se encontró una tendencia temporal significativamente negativa en la condición corporal de los pollos a lo largo de los 26 años del periodo de estudio. Aunque son muchos los factores que pueden incidir en los cambios poblaciones, nuestros datos sugieren una posible relación causal entre el calentamiento global, el comportamiento del cuidado parental y el declive de la población de corneja negra en las zonas climáticas mediterráneas de España.[EN] Cooperative breeding in birds arises when individuals, called helpers, forgo or postpone their reproduction to help raising young that are not their own. Hamilton’s inclusive fitness theory provides a firm theoretical basis for understanding the paradox of helping, but does not apply to societies composed of unrelated individuals. Moreover, in some species living in family groups, indirect benefits seem to be insufficient to explain a delay in own reproduction. Therefore, the existence of direct benefits (access to resources, protection from predators and increased social status, among others) has been hypothesized to explain how these societies have evolved and maintained over time. Importantly, some of the direct benefits proposed would imply that helpers signal their contribution to communal tasks to the rest of the social group.
Most research on cooperative breeding in bird has focused until now on the amount of care that individuals provide, overlooking, other dimensions of young provisioning behaviour, like the distribution over time of nest visits. This temporal dimension, however, might shed light on social aspects of cooperative behaviour that are related to its ultimate function and mechanism. First, looking at the patterns of overlap of provisioning events by different carers can unveil a signalling component of helping that may serve to enhance individual “social prestige” or to show to the dominants that a” rent” has being paid for access to the resources of the territory. Second, recent theoretical models have postulated that an alternation of nest visits among group members could resolve the conflict over brood care. Testing these two aspects in the cooperative society of the carrion crow Corvus corone are the key objectives of this thesis: addressing the direct benefits and signal function of brood provision will shed light on the ultimate function of helping, and investigating the turn taking among carers will help us understanding the stabilising mechanisms of cooperation in this system.
Carrion crows form stable enlarged families in northern Spain, where retained offspring and more distant relatives aid a dominant breeding pair to raise its brood. In this society, male subordinates face strong constraints on independent reproduction and make the best of bad job by investing substantially in helping to increase their indirect fitness. In contrast, the expectation of future reproduction is better for female offspring, because of the higher turnover of breeding females in this population, which explains why on average they are less helpful than males. Under these circumstances, dominants are expected to be more vigilant over the contribution to brood provisioning by female subordinates, which, in turn, might need to show their helpfulness to retain group membership. In accordance with this idea, we found that female retained offspring increased the ‘visibility’ of their contribution by provisioning in front of the dominant breeders significantly more than any other category of group members. In addition, retention of group membership for female offspring was associated with their perceived effort in chick feeding. Our results are consistent with the hypothesis of ‘pay to stay’ and suggest that a signalling component of helping can arise in a ‘typical’ kin-based cooperative society.
Cooperative food provisioning might arise incidentally as a result of the individual efforts of multiple carers that ‘act apart together’, but recent studies on birds suggest that individuals may also engage in active turn taking. However, evidence for individuals responding to each other’s behaviour is controversial, and the potential benefits of such coordination remain unknown. Our results suggested that crow carers alternate in provisioning the nestlings. Importantly, we found that the body mass of nestlings increased significantly with the degree of carers’ alternation, possibly because coordinated groups provided food at more regular intervals. The observed increase in body mass in crows substantially boosted estimated post-fledgling survival rates. Our study demonstrates that alternation in nestling provisioning has measurable fitness benefits in this system. This implies that any mechanism that causes and/or enhances nest alternation would be favoured by natural selection.
However, not only intrinsic and social factors determine parental care in cooperatively breeding birds, but the effects of environmental factors (such as the weather) may also play a relevant role. Meteorological conditions, like temperature and drought, can constrain brood provisioning in some bird species, but the consequences on reproductive success have been rarely quantified. The third objective of this thesis addresses this question in the cooperatively breeding carrion crow by analysing a long-term data set, which covers the last 26 years. Our results showed that individual feeding rates decreased significatively with rising temperatures both in breeders and helpers, while drought was associated with a significant reduction in the effort of the male helpers as compared to the other social categories. The degree of alternation of nest visits by carers was also negatively affected by rising temperature. Consequences on crow reproductive success were detected in terms of body condition of the nestlings, which worsened when temperatures were high during the rearing period. Interestingly, a significant temporal trend was found, with nestling body condition steadily deteriorating over the 26-years study period. Although many factors may concur in causing population changes, our data suggest a possible causal link between global warming, brood caring behaviour and the decline of carrion crow population in the Mediterranean climatic areas of Spai
On the influence of magnetic mineralogy in the tectonic interpretation of anisotropy of magnetic susceptibility in cataclastic fault zones
Of the several factors involved in the development of magnetic fabrics in fault zones at shallow crustal levels, lithology and deformation intensity have probably the most important consequences for the reconstruction of their kinematic history. The basement-involved Cenozoic thrusts in the Demanda Massif (N Spain) provide the opportunity for testing the applicability of anisotropy of magnetic susceptibility (AMS) to the study of deformation in cataclastic fault rocks belonging to shallow fault zones. The Rastraculos thrust is a relatively minor basement thrust (dip-slip movement of 2km defined from cross-sections and geological maps) of Cenozoic age. This thrust contains a re-activated fault zone involving different rock types both belonging to its hangingwall (Palaeozoic) and its footwall (Triassic sandstones and dolostones and Jurassic limestones). AMS results show magnetic foliations parallel or slightly oblique to the fault zone, and both transport-parallel (projected onto the foliation plane) and transport-perpendicular (parallel to the observed intersection lineation) magnetic lineations. The two types of strain/magnetic fabric relationships can be related to deformational and mineralogical features inferred from the direct analysis of thin and polished sections under the microscope and the naked eye, respectively. Analysis of fault rocks in the Rastraculos fault zone indicates that in cataclasites, magnetic fabrics are particularly dependent on lithology and hence magnetic mineralogy. The results obtained prove the usefulness of AMS in fault zones where kinematic indicators are scarce and also give clues on the number of samples necessary to define magnetic susceptibility axes, depending on grain size, ellipsoid shapes and magnetic mineralogy
Self-compacting concrete containing coarse recycled precast-concrete aggregate and its durability in marine-environment-related tests
Marine environments are extremely challenging for the long-term durability of concrete. Prior validation of concrete durability is therefore a prerequisite to guarantee its adequate performance under marine environmental conditions. In this study, the performance of Self-Compacting Concrete (SCC) with variable contents of coarse Recycled Precast-Concrete Aggregate (RPCA) and two different cement contents is assessed in terms of capillary water absorption, natural and accelerated carbonation, resistance to SO2 attack, and moist/dry performance in drinking water, marine water, and sulfate water. These tests are intended to simulate the conditions of a marine environment. In general, the results showed that an SCC containing coarse RPCA of adequate durability under marine conditions could be produced. On the one hand, porosity due to the presence of RPCA increased less as the cement content was increased, which in turn reduced water absorption and SCC carbonation. For example, the effective porosity of the SCC was reduced by 25 % between day 28 and day 180, following the addition of 100 % coarse RPCA. On the other hand, both the SO2-attack and the moist/dry tests revealed that the weight of the SCC with RPCA underwent greater variations, due to the reactions of the cementhydration products with chlorides and sulfates, as well as salt deposition. However, SCC compressive strength was never adversely affected, as the concrete strength increased up to 8 MPa after the drinking-water and the sulfate-water moist/dry tests when using RPCA. According to both Fick's and Parrot's models, the projected service life of all the mixes was over 100 years, regardless of the coarse RPCA content, making this sort of SCC a feasible option for construction in marine environments.This research work was supported by the Spanish Ministry of Universities, MICINN, AEI, EU, ERDF and NextGenerationEU/PRTR [grant numbers PID2020-113837RB-I00; 10.13039/501100011033; TED2021-
129715B-I00]; the Junta de Castilla y León (Regional Government) and ERDF [grant number UIC-231]; and, finally, the University of Burgos [grant number SUCONS, Y135.GI]
Monkeypox in pregnancy: clinical recommendation by the World Association of Perinatal Medicine-WAPM and the Perinatal Medicine Foundation-PMF
The World Health Organization in May 2022 declared the monkeypox virus (MPXV) a health emergency. Since then, over 45,355 cases have been reported, mostly from countries where the disease is not endemic. At the moment, most confirmed cases with travel history are reported to countries in Europe and North America, rather than West or Central Africa where the monkeypox virus is endemic. Its transmission depends on large respiratory droplets and skin-to-skin or skin-to-lesion close physical contact, including oral, anal, and vaginal intercourse therefore, women are also at risk of acquiring it. Given few data available, women’s and clinicians’ concerns about the uncertainty of the clinical course and management are more than understandable, especially so after the SARS-CoV-2 pandemic. Lessons must be learnt from our prior mistakes and pregnant individuals should be included in international registries as well as any studies evaluating new treatments or vaccines. The following recommendation aims to provide the latest evidence about the effect of MPXV in pregnancy as well as recommendations for clinical management
Estudio paleomagnético del volcanismo de Campos de Calatrava
A first systematic paleomagnetic study has been carried out in the upper Miocene-Pliocene volcanísm
of the Campos de Calatrava region. 78 localities have been sampled and 74 oi them yíelded useiul
paleomagnetíc results. A Pliocene paleomagnetic pole has been obtaíned for the {be rían Plate (Lat.=
82.7°N, Long.= 771.6°E, A95= 6.9). On the basis of the magnetíc polarity results a zoníng oi the
voJcanism may be recognízed which could be explaíned by a NE-wardmigration of the volcanism in
thís regíon
Epsilon iron oxide: Origin of the high coercivity stable low Curie temperature magnetic phase found in heated archeological materials
The identification of epsilon iron oxide (-Fe2O3) as the low Curie temperature high coercivity stable phase (HCSLT) carrying the remanence in heated archeological samples has been achieved in samples from two archeological sites that exhibited the clearest evidence of the presence of the HCSLT. This uncommon iron oxide has been detected by Confocal Raman Spectroscopy (CRS) and characterized by rock magnetic measurements. Large numbers of -Fe2O3 microaggregates (in CO) or isolated clusters (in HEL) could be recognized, distributed over the whole sample, and embedded within the ceramic matrix, along with hematite and pseudobrookite and with minor amounts of anatase, rutile, and maghemite. Curie temperature estimates of around 170 degrees C for CO and 190 degrees C for HEL are lower than for pure, synthetic -Fe2O3 (227 degrees C). This, together with structural differences between the Raman spectra of the archeologically derived and synthetic samples, is likely due to Ti substitution in the -Fe2O3 crystal lattice. The -Fe2O3--Fe2O3--Fe2O3 transformation series has been recognized in heated archeological samples, which may have implications in terms of their thermal history and in the factors that govern the formation of -Fe2O3
Maternal and perinatal outcomes in women with advanced maternal age affected by SARS-CoV-2 infection (Phase-2): The WAPM (World Association of Perinatal Medicine) Working Group on COVID-19
Objective To elucidate the role of advanced maternal age (AMA) in determining the outcome of pregnancies complicated by SARS-CoV-2 infection. Methods Multinational cohort study included women with laboratory-confirmed SARS-CoV-2 infection from 76 centers in 27 different countries in Europe, United States, South America, Asia and Australia from 04 April 2020 till 28 October 2020. The primary outcome was a composite measure of maternal mortality and morbidity including admission to intensive care unit (ICU), use of mechanical ventilation (defined as intubation, need for continuous positive airway pressure, extra-corporeal membrane oxygenation), severe respiratory symptoms (including dyspnea and shortness of breath) or death. Results Eight hundred and eighty seven pregnant women were included in the study who were positive SARS-CoV-2 results by RT-PCR (reverse transcriptase-polymerase chain reaction) on their nasal and pharyngeal swab specimens (352 with and 652 with no AMA). The risk of composite adverse maternal outcome was higher in AMA group compared to that of under 35 years of age group, with an OR of 1.99 (95% CI 1.4–2.9; p=0.002). Likewise, women >35 years were also at higher risk of hospital admission (OR: 1.88, 95% CI 1.4–2.5; p<0.001), presence of severe respiratory symptoms (OR: 1.53, 95% CI 1.0–2.3; p=0.04) and/or admission to ICU (OR: 2.00, 95% CI 1.1–3.7; p=0.003); however, no difference was observed in terms of perinatal outcome risk. Conclusion Advanced maternal age is an independent risk factor for adverse maternal outcome in pregnancies complicated by SARS-CoV-2 infection. Accurate risk stratification of women presenting with suspected SARS-CoV-2 infection in pregnancy is warranted in order to identify a subset of women who may benefit from a personalized management, including elective hospitalization and/or prolonged surveillance in order to improve maternal outcome
Management of preterm labor: Clinical practice guideline and recommendation by the WAPM-World Association of Perinatal Medicine and the PMF-Perinatal Medicine Foundation
: This practice guideline follows the mission of the World Association of Perinatal Medicine in collaboration with the Perinatal Medicine Foundation, bringing together groups and individuals throughout the world, with the goal of improving the management of preterm labor. In fact, this document provides further guidance for healthcare practitioners on the appropriate use of examinations with the aim to improve the accuracy in diagnosing preterm labor and allow timely and appropriate administration of tocolytics, antenatal corticosteroids and magnesium sulphate and avoid unnecessary or excessive interventions. Therefore, it is not intended to establish a legal standard of care. This document is based on consensus among perinatal experts throughout the world in the light of scientific literature and serves as a guideline for use in clinical practice
Why Did Red Ereño Limestone Go Red? Linking Scientific Knowledge and Geoheritage Story-Telling (Basque Country, Spain)
Red Ereño is a red-stained ornamental and construction limestone with characteristic white fossil shells. Although exploited since Roman times, marketed worldwide and that the rock itself and its outcrop areas have been included in geological heritage inventories, the origin of its characteristic reddish colour remained unresolved. The aim of this work is to deepen the scientific knowledge of Red Ereño as a basis for understanding the characteristics of this stone and to make this information available for geoconservation actions. The mineralogical and petrological study, mainly based on optical and electron microscopy, X-ray diffraction, and rock magnetism and paleomagnetic techniques, concluded that the red-staining mineral is pigmentary hematite. Moreover, the analysis stated that hematite precipitated after sedimentation but prior to burial diagenesis and before alpine inversion. Based on palaeomagnetic studies, it can be stated that mineralisation occurred during the Late Cretaceous. This work illustrates how scientific research on this potential heritage stone provides key information for geoconservation.This study has been carried out by the UPV/EHU Research Group IT-1678/22 (Government of the Basque Country) in the framework of the project US21/32 under the cooperation agreement between the University of the Basque Country UPV/EHU, Basque Energy Agency (EVE), and Provincial Council of Biscay (BFA). Authors also thank the support of the project PID2019-108753GB-C21 financed by State Research Agency (Spain) [AEI /https://doi.org/10.13039/501100011033]. Open Access funding provided thanks to the CRUE-CSIC agreement with Springer Nature. UPV/EHU Research Group IT-1678/22 (Government of the Basque Country); UPV/EHU, EVE/EEE, DFB/BFA project US21/32
Mechanism of Inhibition of Enveloped Virus Membrane Fusion by the Antiviral Drug Arbidol
The broad-spectrum antiviral arbidol (Arb) inhibits cell entry of enveloped viruses by blocking viral fusion with host cell membrane. To better understand Arb mechanism of action, we investigated its interactions with phospholipids and membrane peptides. We demonstrate that Arb associates with phospholipids in the micromolar range. NMR reveals that Arb interacts with the polar head-group of phospholipid at the membrane interface. Fluorescence studies of interactions between Arb and either tryptophan derivatives or membrane peptides reconstituted into liposomes show that Arb interacts with tryptophan in the micromolar range. Interestingly, apparent binding affinities between lipids and tryptophan residues are comparable with those of Arb IC50 of the hepatitis C virus (HCV) membrane fusion. Since tryptophan residues of membrane proteins are known to bind preferentially at the membrane interface, these data suggest that Arb could increase the strength of virus glycoprotein's interactions with the membrane, due to a dual binding mode involving aromatic residues and phospholipids. The resulting complexation would inhibit the expected viral glycoprotein conformational changes required during the fusion process. Our findings pave the way towards the design of new drugs exhibiting Arb-like interfacial membrane binding properties to inhibit early steps of virus entry, i.e., attractive targets to combat viral infection
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