Abundant dust found in intergalactic space

Galactic dust constitutes approximately half of the elements more massive than helium produced in stellar nucleosynthesis. Notwithstanding the formation of dust grains in the dense, cool atmospheres of late-type stars, there still remain huge uncertainties concerning the origin and fate of galactic stardust. In this paper, we identify the intergalactic medium (i.e. the region between gravitationally-bound galaxies) as a major sink for galactic dust. We discover a systematic shift in the colour of background galaxies viewed through the intergalactic medium of the nearby M81 group. This reddening coincides with atomic, neutral gas previously detected between the group members. The dust-to-HI mass ratio is high (1/20) compared to that of the solar neighborhood (1/120) suggesting that the dust originates from the centre of one or more of the galaxies in the group. Indeed, M82, which is known to be ejecting dust and gas in a starburst-driven superwind, is cited as the probable main source.Comment: 5 pages, 3 figures, 1 table. ApJ Letters in pres

Spin Pumping and Inverse Spin Hall Effect in Platinum: The Essential Role of Spin-Memory Loss at Metallic Interfaces

Through combined ferromagnetic resonance, spin-pumping and inverse spin Hall effect experiments in Co|Pt bilayers and Co|Cu|Pt trilayers, we demonstrate consistent values of spin diffusion length $\ell_{\rm sf}^{\rm Pt}=3.4\pm0.4$ nm and of spin Hall angle $\theta_{\rm SHE}^{\rm Pt}=0.051\pm0.004$ for Pt. Our data and model emphasize on the partial depolarization of the spin current at each interface due to spin-memory loss. Our model reconciles the previously published spin Hall angle values and explains the different scaling lengths for the ferromagnetic damping and the spin Hall effect induced voltage.Comment: 6 pages, 3 figures (main text) and 8 pages supplementary. Published with small modifications in Phys. Rev. Let

The AGN Outflow in the HDFS Target QSO J2233-606 from a High-Resolution VLT/UVES Spectrum

We present a detailed analysis of the intrinsic UV absorption in the central HDFS target QSO J2233-606, based on a high-resolution, high S/N (~25 -- 50) spectrum obtained with VLT/UVES. This spectrum samples the cluster of intrinsic absorption systems outflowing from the AGN at radial velocities v ~ -5000 -- -3800 km/s in the key far-UV diagnostic lines - the lithium-like CNO doublets and H I Lyman series. We fit the absorption troughs using a global model of all detected lines to solve for the independent velocity-dependent covering factors of the continuum and emission-line sources and ionic column densities. This reveals increasing covering factors in components with greater outflow velocity. Narrow substructure is revealed in the optical depth profiles, suggesting the relatively broad absorption is comprised of a series of multiple components. We perform velocity-dependent photoionization modeling, which allows a full solution to the C, N, and O abundances, as well as the velocity resolved ionization parameter and total column density. The absorbers are found to have supersolar abundances, with [C/H] and [O/H] ~0.5 -- 0.9, and [N/H] ~ 1.1 -- 1.3, consistent with enhanced nitrogen production expected from secondary nucleosynthesis processes. Independent fits to each kinematic component give consistent results for the abundances. The lowest-ionization material in each of the strong absorbers is modeled with similar ionization parameters. Components of higher-ionization (indicated by stronger O VI relative to C IV and N V) are present at velocities just redward of each low-ionization absorber. We explore the implications of these results for the kinematic-geometric-ionization structure of the outflow.Comment: 12 pages, 10 figures, emulateapj, accepted for publication in Ap

Learning science towards a sustainable development

The learning of sciences can be very stimulating. One cannot say there exists a perfect pedagogical method but our experience proved that actually going through the situations makes it possible for the students to learn the concepts more effectively and efficiently. Concrete experiences help students acquire knowledge with more ease [1]. The objective of the project herein reported is to get the students to learn science and simultaneously awaken to the principles of sustainable development. In the context of the programs of various disciplines, the use of a general and globalizing theme will allow to integrate various areas of knowledge and contribute to better learning. As collateral objectives, this project also intends to promote the level of literacy of the students and consequently of the society they belong to [2]. The United Nations entitled 2003-2012, the Literacy decade. Scientific literacy is fundamental for the development of our societies and humanity. The project will be implemented in other schools, located in mountain regions, in different European countries, that will share our experiences and knowledge. A number of exchange visits of groups of teachers and students will be organized in order to enhance the sense of European citizenship among the participants in the project and there schools. Science fairs will be organized where the work developed will be presented to the community

Evaluation of performance under fire of compressed earth blocks

In this paper are presented and discussed the main results of fire resistance tests on walls made of soil-cement and Kraftterra compressed earth blocks (CEB). Within this research it was intended to evaluate the fire resistance of walls made with CEB, with and without cellulose pulp incorporation deriving from recycling of cement sacks. Firstly, it is described the Kraftterra production processes and the fire resistance test campaign. Then, the performance of the blocks under analysis in terms of fire resistance is compared

Tratamiento médico de la estenosis arterial intracraneal. ¿Es el mismo en prevención primaria que en secundaria?

In this study we review the risk factors associated with the formation and progression of an atheroma plaque, the mechanism involved in cerebral ischemia secondary to intracranial atheromatosis and possible medical treatment in primary and secondary prevention. DEVELOPMENT: Medical treatment of intracranial stenoses (ICS) is aimed at stopping the progression of the atheroma plaque and at preventing recurrences in the case of symptomatic stenoses. It is based on the control of vascular risk factors, the use of statins and antithrombotic therapy (antiplatelet or anticoagulation drugs). Although antiplatelet agents have not proved to be beneficial in the primary prevention of stroke, they are recommended in patients with ICS in order to lower the risk of heart attack associated with this pathology. The use of antiplatelet drugs in the secondary prevention of ischemic stroke secondary to an ICS is based on clinical trials which have shown that antiaggregation prevents non-cardioembolic strokes. Nevertheless, several retrospective studies have observed that oral anticoagulation is better than antiaggregation with aspirin. Two prospective clinical trials are currently being conducted which will, in the next few years, help to determine what the first choice medical treatment is for this group of patients. CONCLUSIONS: Medical treatment of ICS patients must include the control of vascular risk factors and the use of statins. New studies are needed to be able to establish the first choice antithrombotic drug in secondary prevention

A 4-D dataset for validation of crystal growth in a complex three-phase material, ice cream

Four dimensional (4D, or 3D plus time) X-ray tomographic imaging of phase changes in materials is quickly becoming an accepted tool for quantifying the development of microstructures to both inform and validate models. However, most of the systems studied have been relatively simple binary compositions with only two phases. In this study we present a quantitative dataset of the phase evolution in a complex three-phase material, ice cream. The microstructure of ice cream is an important parameter in terms of sensorial perception, and therefore quantification and modelling of the evolution of the microstructure with time and temperature is key to understanding its fabrication and storage. The microstructure consists of three phases, air cells, ice crystals, and unfrozen matrix. We perform in situ synchrotron X-ray imaging of ice cream samples using in-line phase contrast tomography, housed within a purpose built cold-stage (-40 to +20oC) with finely controlled variation in specimen temperature. The size and distribution of ice crystals and air cells during programmed temperature cycling are determined using 3D quantification. The microstructural evolution of three-phase materials has many other important applications ranging from biological to structural and functional material, hence this dataset can act as a validation case for numerical investigations on faceted and non-faceted crystal growth in a range of materials