Temperature dependence of the magnetic properties in LaMnO_(3+δ)

Data are presented on the thermal dependence of the hysteretic properties of cationic vacancies including manganite samples of composition LaMnO_(3+δ)(δ=0.05 and 0.12). Our results evidence the presence in both samples of two magnetic phases having ferro- and antiferromagnetic orders, respectively. The temperature dependence of the coercivity and relaxational properties of the samples is closely linked to the connectivity of the magnetic moment bearing Mn^(3+)-Mn^(4+) ferromagnetic clusters that demagnetize independently in the case of the δ=0.05 sample and collectively in that of the δ=0.12 one, as evidenced from the activation volume results (delta=0.05) which yielded a size of the same order magnitude as that obtained in previous works for the Mn^(3+)-Mn^(4+) ferromagnetic cluster size

Ice thickness, internal structure and subglacial topography of Bowles Plateau ice cap and the main ice divides of Livingston Island, Antarctica, by ground-based radio-echo sounding

Ground-based radio-echo sounding studies of Livingston Island ice cap, Antarctica, were started in 1999 at Johnsons and Hurd glaciers, in Hurd Peninsula, close to the Spanish Antarctic Station Juan Carlos I. Radar profiling continued in 2000 and 2003 along the main ice divides of the ice cap and in the upper parts of Huron and another unnamed glacier, both draining Bowles ice plateau towards Moon Bay. More detailed radar studies on Bowles ice plateau were performed in December 2006 using an icepenetrating radar VIRL-6, with central frequency of 20 MHz, and a Ramac/GPR radar with 200 MHz antennae, intended for deep penetration to bedrock and shallow penetration to determine the firn layer thickness, respectively. The radar equipment was installed on two Nansen sledges and two pulkas towed by snowmobiles. Georeferencing of radar data was accomplished by using a GPS receiver working in stand-alone mode. The endpoints of the radar profiles were more accurately georeferenced using differential GPS. The data collected were used to construct the ice thickness, glacier surface and bedrock elevation maps and to estimate the average ice thickness and total ice volume of the plateau, as well as the spatial distribution of snow accumulation. For time-to-depth conversion, an average radio-wave velocity determined from common midpoint measurements at several locations in Hurd Peninsula was used. The thickest ice (550 m) was found in the upper part of Huron glacier. This thickness is almost twice the maximum thickness found along the main ice divides (330 m) and almost three times that found in Hurd Peninsula (200 m). The bedrock in two large areas in the northern and southern parts of the plateau, towards Moon Bay and Huntress glacier, lies below sea level, at depths down to -200 m, indicating that, should the ice cap fully disappear, several separated islands would likely appear, even if isostacic rebound is taken into account

Aislamiento de un extracto de BMP y estudio anatomopatológico del fenómeno de inducción ósea tras su implante en defectos óseos

El objetivo del presente trabajo fue determinar el potencial osteogénico de la proteína morfogenética ósea (BMP) en la reparación de grandes defectos diafisarios. Además, se investiga la acción coadyuvante de la fibronectina (FN). La BMP fue extraída a partir de hueso cortical bovino. Se utilizaron un total de 108 ratas Sprague Dawley. En cada animal, se resecó un segmento de diáfisis femoral de 1.5 cm, siendo inmovilizado el defecto óseo con una aguja en omega. Se rellenó el defecto implantando 25 mg de BMP con o sin 0.5 mg de FN en una cápsula de gelatina (36 animales en ambos grupos). Los resultados se compararon con los obtenidos en otro grupo (36 animales) en el que sólo se implantó FN que sirvió como grupo control. El proceso de reparación se evaluó mediante métodos histológicos y ultraestructurales. La aparición del fenómeno de inducción ósea con reconstrucción del defecto óseo fue mayor en el grupo con implante de BMP más FN (23 animales, 64%) que en el grupo en el que sólo se implantó BMP (20 animales, 56%). Ningún animal del grupo control manifestaba signos de inducción ósea.The aim of the present work was to evaluate the osteogenic potential of Bone Morphogenetic Protein (BMP) for reparation of large segmental bone defects. In addition, the coadjuvant efect of fibronectin (FN) was investigated. BMP was partially purified from bovine cortical bone. A total of 108 Sprague Dawley rats were used in the experiment. Diaphyseal segments of the femur (1.5 cm) were removed in each animal, manteinant the bone defect with a wire. A gelatine capsula containing 25 mg of BMP without or with 0.5 mg of FN, were implanted into the bone defect (36 animal in each group). Results were compared to those obtained in a control group (36 animals) in which FN alone was implanted. The bone repair process was assessed by histologic and ultrastructural methods. Bone induction with reconstruction of the defect was found more of ten in the group with both BMP and FN implanted (23 animals, 64%) than in the group with BMP implant alone (20 animals, 56%). Animals of the control group showed no bone induction. The results suggest that BMP augments the capacity of the host bed to sucessfully regenerate large segmental bone defects. FN seens to increase bone induction. This protein migth stabilize BMP locally improving contact between BMP and the surrounding cells

Cross‐sectional study about impact of parental smoking on rhinitis symptoms in children

[Abstract] Objective. Assess the prevalence of rhinitis and exposure to environmental tobacco smoke (ETS) of children in our community and its relationship with symptoms of rhinitis Methods (design, setting, participants, main outcome measures). Cross‐sectional study using questionnaire on rhinitis of the International Study of Asthma and Allergies in Childhood, in children (6‐7 years) and adolescents (13‐14 years). Categories: “rhinitis ever”, “recent rhinitis”, “recent rhinoconjunctivitis”, “severe rhinoconjunctivitis”. Parental smoking: (i) neither parent smokes; (ii) only the mother smokes; (iii) only the father smokes; and (iv) both parents smoke. Odds ratio of the prevalence of symptoms of rhinitis according to ETS exposure was calculated using logistic regression. Results. 10 690 children and 10 730 adolescents. The prevalence of “rhinitis ever” in children: 29.4%, “recent rhinitis” 24%, “recent rhinoconjunctivitis” 11.5% and “severe rhinoconjunctivitis” 0.1%. In adolescents: 46.2%, 34.5%, 16.2% and 0.2%, respectively. Environmental tobacco smoke exposure in the home occurred in 51% of cases. Parental smoking was associated with a higher prevalence of forms of rhinitis in adolescents when only the mother was a smoker. In children when both parents were smokers. Conclusion. Rhinitis is highly prevalent in our community. Environmental tobacco smoke exposure is still very common. The relationship between ETS and rhinitis symptoms in children of this community is not as robust as that found for asthma

Magnetic Field Generation in Stars

Enormous progress has been made on observing stellar magnetism in stars from the main sequence through to compact objects. Recent data have thrown into sharper relief the vexed question of the origin of stellar magnetic fields, which remains one of the main unanswered questions in astrophysics. In this chapter we review recent work in this area of research. In particular, we look at the fossil field hypothesis which links magnetism in compact stars to magnetism in main sequence and pre-main sequence stars and we consider why its feasibility has now been questioned particularly in the context of highly magnetic white dwarfs. We also review the fossil versus dynamo debate in the context of neutron stars and the roles played by key physical processes such as buoyancy, helicity, and superfluid turbulence,in the generation and stability of neutron star fields. Independent information on the internal magnetic field of neutron stars will come from future gravitational wave detections. Thus we maybe at the dawn of a new era of exciting discoveries in compact star magnetism driven by the opening of a new, non-electromagnetic observational window. We also review recent advances in the theory and computation of magnetohydrodynamic turbulence as it applies to stellar magnetism and dynamo theory. These advances offer insight into the action of stellar dynamos as well as processes whichcontrol the diffusive magnetic flux transport in stars.Comment: 41 pages, 7 figures. Invited review chapter on on magnetic field generation in stars to appear in Space Science Reviews, Springe

Non-thermal emission processes in massive binaries

In this paper, I present a general discussion of several astrophysical processes likely to play a role in the production of non-thermal emission in massive stars, with emphasis on massive binaries. Even though the discussion will start in the radio domain where the non-thermal emission was first detected, the census of physical processes involved in the non-thermal emission from massive stars shows that many spectral domains are concerned, from the radio to the very high energies. First, the theoretical aspects of the non-thermal emission from early-type stars will be addressed. The main topics that will be discussed are respectively the physics of individual stellar winds and their interaction in binary systems, the acceleration of relativistic electrons, the magnetic field of massive stars, and finally the non-thermal emission processes relevant to the case of massive stars. Second, this general qualitative discussion will be followed by a more quantitative one, devoted to the most probable scenario where non-thermal radio emitters are massive binaries. I will show how several stellar, wind and orbital parameters can be combined in order to make some semi-quantitative predictions on the high-energy counterpart to the non-thermal emission detected in the radio domain. These theoretical considerations will be followed by a census of results obtained so far, and related to this topic... (see paper for full abstract)Comment: 47 pages, 5 postscript figures, accepted for publication in Astronomy and Astrophysics Review. Astronomy and Astrophysics Review, in pres

Response Surface Method to Calculate Energy Savings Associated with Thermal Comfort Improvement in Buildings

In developed countries, a large part of the building stock in 2050 will consist of currently existing buildings. Consequently, in order to achieve the objectives in terms of energy efficiency in the building sector we must consider not only new infrastructures but also the old ones. A reduction in energy consumption for climate control of between 50 and 90% can be achieved by rehabilitation and the implementation of different energy efficiency measures. Currently, these measures to reduce energy consumption and associated CO2 emissions can be modelled using computer tools. However, high precision and detail of thermal behaviour models through simulations can mean a great computational cost for companies, which results in a blockage of servers and workers. In this paper, the Response Surface Methodology (RSM) is presented as an innovative methodology for the simplification of models for calculation of the energy savings associated with thermal comfort improvement in buildings. A single-family house model, located in three different climates, is presented as a case study in order to validate the proposed methodology. Different scenarios were simulated, addressing heating and cooling temperature set points and external wall insulation represented by the transmittance (U-value). Results obtained from energy simulation using Design Builder were contrasted against those estimated from the simplified model extracted from the RSM analysis. The results revealed a deviation lower than 3% when comparing both methods. Therefore, the simplified mathematical prediction models are demonstrated to be suitable for the study of the energy performance of buildings, saving computational time, costs and associated human resources. © 2022 by the authors. Licensee MDPI, Basel, Switzerland

System Virtualization Tools for Software Development

The configuration complexity of preproduction sites coupled with access-control mechanisms often impede the software development life cycle. Virtualization is a cost-effective way to remove such barriers and provide a test environment similar to the production site, reducing the burden in IT administrators. An Eclipse-based virtualization tool framework can offer developers a personal runtime environment for launching and testing their applications. The authors have followed a model-driven architecture (MDA) approach that integrates best-of-breed virtualization technologies, such as Xen and VDE.ITECBAN is an IT innovation project partially funded by CENIT (a Spanish public R&D program). We're grateful to MITYC (Ministerio de Industria, Turismo y Comercio) and CDTI (Centro para el Desarrollo Tecnológico e Industrial) for supporting ITECBAN through CENIT