Geopolítica del registro fósil de homínidos africanos

Proyecto fin de carrera en Biología Evolutiva y BiodiversidadA lo largo del último siglo se han descubierto en África multitud de yacimientos con restos fósiles de homínidos. Estos yacimientos se distribuyen por el norte de África, en la región central del Chad, en el este de África y en Sudáfrica. Para explicar la gran cantidad de yacimientos al este del Gran Valle del Rif, Yves Coppens propuso la hipótesis del East Side Story, la cual fue rebatida a causa de los descubrimientos de Abel y Toumai en el Chad. Han sido 54 los yacimientos estudiados. Para la digitalización y la georreferenciación de la información de todos estos yacimientos se utilizó el programa ArcGIS en combinación con imágenes satélites, geológicas y geográficas de alta resolución. Con esta información ha sido posible valorar en los resultados la posibilidad de la existencia de sedimentos geológicos, barreras geográficas y fenómenos políticos y sociales que hayan podido condicionar el hallazgo y la distribución de especies fósiles. Los resultados se han centrado en los lugares y países donde potencialmente pudieron existir homínidos en el Plioceno y Cuaternario pero que, por uno u otro motivo, no disponen de registro de yacimientos paleoantropológicos. Observamos que algunas variables pueden no haber influido en este hecho, pero otras, como las situaciones políticas de los países, probablemente sean los motivos del pequeño y sesgado registro fósil del que se tiene constancia en la actualidad en relación con nuestras raíces más profundas

Metodología para el diseño de envolventes de volantes de inercia

Actualmente, se está viviendo un auge de la tecnología de acumulación de energía. Durante las últimas décadas se está investigando y optimizando los diferentes sistemas de almacenamiento, por los beneficios que suponen. Entre estos sistemas se encuentran los volantes de inercia, usados en múltiples aplicaciones, desde el sector energético hasta la industria del transporte. Para optimizar su rendimiento, es conveniente diseñar los componentes adicionales del volante, y no solo el propio volante de inercia. En este trabajo se propone una metodología para el diseño de envolventes de volantes de inercia, con el objetivo de minimizar las pérdidas aerodinámicas del volante. Para ello, se diseñan la carcasa protectora que lo envuelve y el fluido que queda entre ambos. Los diseños se hacen teniendo en cuenta los movimientos y deformaciones de la estructura en su funcionamiento, de tal manera que el volumen que ocupa el fluido se minimiza. Finalmente, se estudia el fluido para determinar el punto de funcionamiento óptimo y diseñar la presión a la que debe operar.Nowadays, there has been a rise of energy storage technology. For the last decades, different storages systems are being investigated and optimized, because of the benefits they have. Among these systems, there are the flywheels, which are used in numerous applications, from energy industry to transport industry. To optimize their efficiency, it´s appropriate to design the additional components of the flywheels, and not just the flywheels themselves. In this present work, a methodology for the design of flywheels is proposed, with the aim of minimizing the aerodynamic drag. This requires designing the containment that covers it and the fluid that is between them. The designs are made considering the movements and deformations of the working structure, so the volume which is occupied by the fluid is minimum. Finally, to determinate the optimum operating point and the pressure in which it must operate, the fluid is studied.Ingeniería Mecánic

Fluid dynamics of mixing in the tanks of small vanadium redox flow batteries: Insights from order-of-magnitude estimates and transient two-dimensional simulations

This paper investigates the fluid dynamics of mixing in the tanks of small-scale vanadium redox flow batteries. These systems use two redox pairs dissolved in separate electrolytes to convert electrical energy into chemical energy, a process that can be reversed in an efficient way to restore the initial electrical energy with negligible chemical losses. After flowing through the electrochemical cell, the electrolytes are stored in separate tanks, where they discharge as submerged jets with small temperature and composition changes compared to the electrolyte already present in the tanks. The subsequent mixing process is critical for battery performance, as imperfect mixing tends to reduce the energy capacity and may lead to asymmetric battery operation. The analysis starts using order-of-magnitude estimates to determine the conditions under which the mixing process is dominated by momentum or buoyancy. Transient two-dimensional simulations illustrate the different flow regimes that emerge in the tanks under laminar flow conditions. The results show that, contrary to the common assumption, the electrolytes do not mix well in the tanks. In the presence of high-momentum -- and, specially, positively buoyant -- jets, a significant fraction of the electrolyte remains unmixed and unreacted for long periods, thus reducing the energy capacity. The results also show that the availability of reliable electrolyte properties is crucial for the accuracy of the numerical simulations, as, under the mixed convection conditions that typically prevail in vanadium redox flow batteries, small density variations can significantly impact the long-term mixing of the electrolytes. In particular, in momentum-dominated flows the cumulative effect of density changes over time eventually leads to flow instabilities that significantly promote mixing; therefore, they should be taken into account in future studies

Cuajada con melao

Maestro (a) en Artes VisualesPregrad

Short communication: Broadening the diagnosis panel of reproductive pathogens associated with abortion in ruminants

Diagnosis of abortion in cattle, sheep and goat have been mainly focused on abortive pathogens with a recognized impact in outbreaks, but the aetiologic diagnosis rates have been historically low worldwide. Thus, we analysed the presence of pathogens in abortion outbreaks, focusing on the less-common pathogens in cattle farms with control programmes for reproductive pathogens, and in ovine and caprine farms. Thirty-one cases from Galician farms submitted to our laboratory during 2013-2015 were analysed (16 bovine, 7 ovine and 8 caprine farms) by polymerase chain reaction and culture from foetal tissues (n = 52 foetuses). Diagnosis was reached in 21/31 farms: 9/16 in bovine, 6/7 in ovine and 6/8 in caprine. Campylobacter spp. were found in all three species (3/9 diagnosed cases in bovine, 2/6 in ovine and 4/6 in caprine). Furthermore, Ureaplasma diversum was detected in cattle (4/9 of diagnosed cases), Bovine Viral Diarrhoea Virus – 2 was detected in sheep (2/6) and Neospora caninum in goats (1/6). Our results prove the occurrence of abortion in response to pathogens that are traditionally considered less relevant and rarely included in the diagnosis of ruminant abortion. Therefore, differential diagnosis of abortion should consider these pathogens (at least when other causes have been ruled out), to effectively control abortion in farms

Environmental distribution of Porcine Circovirus Type 2 (PCV2) in swine herds with natural infection

Porcine circovirus type 2 (PCV2) is the aetiological agent of PCV2-Systemic Disease (PCV2-SD) and PCV2-Subclinical Infection (PCV2-SI). PCV2 is highly resistant to environmental conditions, being able to remain in the farm environment and thus represent a risk for infection maintenance. The aim of this study was to identify, under field conditions, the possible critical points in the environment of non-vaccinated farrow-to-weaning swine farms where PCV2 could accumulate and persist. For that, environmental samples from five swine farms with PCV2-SD or PCV2-SI were taken and analysed by qPCR, including different farm areas, farm personnel and management implements. PCV2 DNA was detected in the environment of all farms (42.9% of positive samples). Overall, the PCV2-SD herd seemed to present more positive samples and higher viral loads than the PCV2-SI herds. At individual farm level, weaning areas appeared to be the most contaminated facilities. In addition, PCV2 was found at high levels in most samples from farm workers, especially work boots, suggesting that they may play a role in within-farm transmission. In addition, PCV2 was detected in areas without animals the like warehouses, offices and farm perimeter. Therefore, this study is helpful to improve measures to reduce within-farm PCV2 dissemination.This work has been funded by the European PCV2-Award 2016 sponsored by Boehringer Ingelheim Animal Health, GermanyS

Seroprevalence of Toxoplasma gondii and Neospora caninum in goats from north-western Spain

Introduction and objective: Toxoplasma gondii and Neospora caninum are protozoans involved in reproductive failure especially in ruminant livestock. The objective was to estimate the seroprevalence of both parasites in goats from north-western Spain and to study the influence of some factors on seropositivity. Material and Methods: Blood samples from 638 goats were collected in 50 farms. Presence of T. gondii and N. caninum antibodies were detected by direct agglutination and competitive ELISA techniques, respectively. The risk factor analysis was performed using a mixed-effects logistic regression. Results: Individual (48%) and herd-level (74%) T. gondii seroprevalence values were high; the within-herd prevalence was 53%. In contrast, 6% of animals tested positive to N. caninum and 38% of the herds had at least one positive animal, with a true within-herd prevalence of 10%. Mixed infections were limited; 91% of N. caninum seropositive goats were also positive to T. gondii The risk factor analysis showed that T. gondii seroprevalence is influenced by the presence of sheep in the farm (OR=4.9) and the seropositivity to N. caninum (OR=16.5); goats from the Central-coastal area, more humid and warm, had a 15.7-fold probability of being seropositive to T. gondii than those from the Mountainous area. Cross-breed goats (OR=4.5) and the seropositivity to [i]T. gondii [/i](OR= 9.5) were factors associated with N. caninum seropositivity. Conclusions: The high T. gondii seroprevalence in goats constitute a noticeable zoonotic risk. The consideration of the risk factors identified in designing T. gondii and N. caninum control programs in goat herds should allow the implementation of more efficient measures, avoiding the appearance of outbreaks of reproductive disorders by both protozoans in goatsThe authors express their thank to OVICA (Galician Association of Ovine and Caprine Breeders), BOAGA (Galician Autochthonous Breed Federation) and the veterinarians of the ADSG ACIVO for their collaboration in this study. This work was supported by a Programme for consolidating and structuring competitive research groups (GRC2015/003, Xunta de Galicia) and by the Research Project ‘RUMIGAL: Rede de estudomultidisciplinar dos ruminantesen Galicia’ (R2014/005, REDES, Xunta de Galicia)S

Efficacy of two commercial ready-to-use PCV2 and mycoplasma hyopneumoniae vaccines under field conditions

Porcine Circovirus Type 2 (PCV2) and Mycoplasma hyopneumoniae are economically important pathogens in swine farms. Vaccination is the main preventive measure for both infections. In order to test two ready-to-use bivalent vaccines, 646 piglets from a herd actively infected with both pathogens were stratified according to the sow parity number and randomly assigned to three groups: A and B were vaccinated with two different vaccines, respectively, while C remained as the unvaccinated control. Vaccine efficacy was assessed based on the weight, average daily weight gai (ADWG), degree of lung lesions, presence of PCV2 viremia by qPCR and presence of PCV2 and M. hyopneumoniae antibody levels by ELISA. Our data revealed that the sow parity did not influence the vaccine outcomes. Good results for most of the analyzed parameters were observed in both vaccinated groups. ADGW and final weight were higher and lung lesions were less evident in both vaccinated groups than in the control one, but only Group A showed a significant improvement. PCV2 viremia was not detected in Group A, but it did appear in Group B coinciding with its peak in Group C. Finally, both the PCV2 and M. hyopneumoniae serological patterns differed depending on the employed vaccineS

Thermo-fluid study of the upc race-track microtron cooling system

The cooling system of the race-track microtron (RTM), which is under construction at the Universitat Politècnica de Catalunya (UPC), has been simulated by means of a computational fluid dynamics (CFD) software. The hydraulic and thermal performance of the system for various operation conditions has been studied. Firstly, the hydraulic model has been validated by comparison with experimental measurements at different flow rates. Then, the cooling fluid temperatures and the pressure losses of the system have been determined and the capacity of the current design to remove the generated heat at nominal power has been confirmed. Finally, the maximum and average wall temperatures and heat transfer coefficients inside the accelerating structure have been calculated. These results have allowed us to localize sections of the cooling system with a low convection due to detached flows where, therefore, a risk of zones of high temperatures exists. An optimization of the cooling circuit with the aim to reduce such high temperature zones has been proposed.Postprint (published version