756 research outputs found
Graphical tools for helping firefighters in victim rescues. Assessment during a live fire training program
This study compares three different methods to communicate the features of a building to firefighters, before starting a victim rescue during a live fire training program. Participants in this study did not previously know the hotel used for developing the activities. The effective number of participants was 144, all professional firefighters. One of the exercises in this training program was thoroughly designed not only for training purposes, but also to test different guide versions. The innovative guides were based on two different technologies (simple stapled sheets of paper and digital content displayed on a tablet) and were developed using several graphical tools (conventional pictures, aerial images captured with drone, 3D models, 360° pictures, etc.). With the intention of facilitating firefightersâ activity during a victim rescue, results obtained using these tools were compared with a conventional communication method. The assessment methodology applied in this study included the use of an anonym questionnaire, as well as the analysis of the videos captured with action cameras, attached with a harness to the chest of two of the four firefighters in every team, during the training activities. Thanks to these videos, it was possible to compare the time required for rescuing the victim and to observe followed paths, visited rooms and substantial information about the tested tools, including valuable participantsâ comments. For in emergency situations, the tools described in this paper were preferred to the already existent self-protection plans, usually considered too extensive for fast communication, a matter of special importance in victim rescues
Is true friendship possible on Facebook? A study from the psychological perspective of LaĂn Entralgo
The present work aims to analyse the meaning of the concept of friendship through the study of the work of the doctor and philosopher Pedro LaĂn Entralgo. The initial hypothesis of the study is that the concept of friendship has been used instrumentally by social media networks, and that these do not offer the conditions necessary to fully experience true friendship. To verify this, we focused on the study of the psychological dimensions of friendship proposed by the author, identifying a series of variables and conducting an analysis by means of a survey of university students who are active users of the platform. With these results the descriptive statistics were extracted and a nonparametric analysis was performed of the variables to determine if Facebook does in fact offer the conditions necessary for to experience true friendship in its psychological dimensions. As the results show, to experience true friendship on social networks is difficult, given that the nature of the interactions between users of the platform are not appropriate for this experience. In calling this different type of relationship friendship Facebook benefits from an attractive hook which leads users to generate contacts as a form of currency which benefits the business model of the social media platform. The concept of true friendship is altered, deformed and displaced in favour of other types of relationships.El presente trabajo tiene como objetivo analizar el significado del concepto de amistad a travĂ©s del estudio de la obra del mĂ©dico y filĂłsofo Pedro LaĂn Entralgo. La hipĂłtesis inicial del estudio es que el concepto de amistad ha sido utilizado instrumentalmente por las redes sociales, y que estas no ofrecen las condiciones necesarias para la vivencia plena de la verdadera amistad. Para comprobarlo, nos centramos en el estudio de las dimensiones psicolĂłgicas de la amistad que propone el autor, identificando una serie de variables y realizando un anĂĄlisis mediante una encuesta a estudiantes universitarios que son usuarios activos de la plataforma. Con estos resultados se extrajo la estadĂstica descriptiva y se realizĂł un anĂĄlisis no paramĂ©trico de las variables para determinar si Facebook efectivamente ofrece las condiciones necesarias para la vivencia de la verdadera amistad en sus dimensiones psicolĂłgicas. Como muestran los resultados, la experiencia de la verdadera amistad en las redes sociales es difĂcil, dado que la naturaleza de las interacciones entre los usuarios de la plataforma no son las adecuadas para esta experiencia. Al llamar amistad a este tipo diferente de relaciĂłn, Facebook se beneficia de un atractivo gancho que lleva a los usuarios a generar contactos como moneda de cambio que favorece el modelo de negocio de la plataforma de redes sociales. El concepto de verdadera amistad se altera, deforma y desplaza a favor de otro tipo de relaciones
WEDM Manufacturing Method for Noncircular Gears, Using CAD/CAM Software
Noncircular gears are used in several technological applications in order to enhance the performance of different mechanical instruments (flow meters, bikes, internal combustion engines, etc.), in order to unify speed in assembly lines and in research. Noncircular gears are typically manufactured by shaving: milling each tooth or by generation. This requires controlling the geometric and kinematic variables in the process.
In this research, a method to manufacture elliptical and oval gears using wire electro-discharge machining (WEDM) is presented. This is a continuous procedure, and its performance is not inferior to the previously mentioned methods. Mathematical models for manufacturing elliptical and oval gears are presented, simulations are carried out, and this method is implemented in a WEDM machine, obtaining two pairs of elliptical and oval gears. This method could be useful in the manufacturing of injection moulds or custom-made metallic gears.
Finally, a discussion using bibliographic references is presented about the surface finish and the consequences of using WEDM in comparison to other shaving methods which do not involve a material phase change
From thermal to electroactive graphene nanofluids
Here, we describe selected work on the development and study of nanofluids based on graphene and reduced graphene oxide both in aqueous and organic electrolytes. A thorough study of thermal properties of graphene in amide organic solvents (N,N-dimethylformamide, N,N-dimethylacetamide, and N-methyl-2-pyrrolidone) showed a substantial increase of thermal conductivity and specific heat upon graphene integration in those solvents. In addition to these thermal studies, our group has also pioneered a distinct line of work on electroactive nanofluids for energy storage. In this case, reduced graphene oxide (rGO) nanofluids in aqueous electrolytes were studied and characterized by cyclic voltammetry and charge-discharge cycles (i.e., in new flow cells). In addition, hybrid configurations (both hybrid nanofluid materials and hybrid cells combining faradaic and capacitive activities) were studied and are summarized here
Travertines associated with the Alhama-Jaraba thermal waters (NE, Spain): Genesis and geochemistry
Freshwater carbonates are interesting archives in palaeoenvironmental reconstructions. However, more studies of those systems are needed to fully understand past environments. In this work the actively-forming travertines of the Alhama-Jaraba thermal system were studied for the first time in order to evaluate the relationship between the geochemical and mineralogical composition and the environmental conditions during their formation. With that aim, a combination of petrographical, mineralogical, geochemical and stable isotope analyses were carried out. These carbonates provide a natural laboratory for the study of the effect of different variables (natural and anthropogenic) on carbonate precipitation. The results showed that there is a close relationship between the mineralogy of the solid precipitates and the formation temperature, and only the samples formed from overheated waters (40â60 °C) show significant concentrations of aragonite. Aragonite-bearing samples show higher concentrations in Sr, Ba and U while calcitic solids are enriched in Mg. These differences could be attributed to mineralogy, temperature or different precipitation rates. The geochemical evaluation of the chemistry of both the solids and their parental waters suggests that differences in the rate of CO2-degassing and, in some cases, evaporation are the primary environmental controls on isotopic compositions. In addition, the results show that, if strong evaporation and CO2-degassing are involved, calcite precipitation occurs under conditions of isotopic disequilibrium with its parental water. The results of our study are useful to interpret old depositional environments and palaeotemperatures
The ALHAMBRA Survey: Bayesian Photometric Redshifts with 23 bands for 3 squared degrees
The ALHAMBRA (Advance Large Homogeneous Area Medium Band Redshift
Astronomical) survey has observed 8 different regions of the sky, including
sections of the COSMOS, DEEP2, ELAIS, GOODS-N, SDSS and Groth fields using a
new photometric system with 20 contiguous ~ filters covering the
optical range, combining them with deep imaging. The observations,
carried out with the Calar Alto 3.5m telescope using the wide field (0.25 sq.
deg FOV) optical camera LAICA and the NIR instrument Omega-2000, correspond to
~700hrs on-target science images. The photometric system was designed to
maximize the effective depth of the survey in terms of accurate spectral-type
and photo-zs estimation along with the capability of identification of
relatively faint emission lines. Here we present multicolor photometry and
photo-zs for ~438k galaxies, detected in synthetic F814W images, complete down
to I~24.5 AB, taking into account realistic noise estimates, and correcting by
PSF and aperture effects with the ColorPro software. The photometric ZP have
been calibrated using stellar transformation equations and refined internally,
using a new technique based on the highly robust photometric redshifts measured
for emission line galaxies. We calculate photometric redshifts with the BPZ2
code, which includes new empirically calibrated templates and priors. Our
photo-zs have a precision of for I<22.5 and 1.4% for
22.5<I<24.5. Precisions of less than 0.5% are reached for the brighter
spectroscopic sample, showing the potential of medium-band photometric surveys.
The global shows a mean redshift =0.56 for I=0.86 for
I<24.5 AB. The data presented here covers an effective area of 2.79 sq. deg,
split into 14 strips of 58.5'x15.5' and represents ~32 hrs of on-target.Comment: The catalog data and a full resolution version of this paper is
available at https://cloud.iaa.csic.es/alhambra
Transfer learning for galaxy morphology from one survey to another
© 2018 The Author(s). Published by Oxford University Press on behalf of the Royal Astronomical Society.Deep Learning (DL) algorithms for morphological classification of galaxies have proven very successful, mimicking (or even improving) visual classifications. However, these algorithms rely on large training samples of labelled galaxies (typically thousands of them). A key question for using DL classifications in future Big Data surveys is how much of the knowledge acquired from an existing survey can be exported to a new dataset, i.e. if the features learned by the machines are meaningful for different data. We test the performance of DL models, trained with Sloan Digital Sky Survey (SDSS) data, on Dark Energy survey (DES) using images for a sample of 5000 galaxies with a similar redshift distribution to SDSS. Applying the models directly to DES data provides a reasonable global accuracy ( 90%), but small completeness and purity values. A fast domain adaptation step, consisting in a further training with a small DES sample of galaxies (500-300), is enough for obtaining an accuracy > 95% and a significant improvement in the completeness and purity values. This demonstrates that, once trained with a particular dataset, machines can quickly adapt to new instrument characteristics (e.g., PSF, seeing, depth), reducing by almost one order of magnitude the necessary training sample for morphological classification. Redshift evolution effects or significant depth differences are not taken into account in this study.Peer reviewedFinal Accepted Versio
Rapid host adaptation by extensive recombination
Experimental investigations into virus recombination can provide valuable insights into the biochemical mechanisms and the evolutionary value of this fundamental biological process. Here, we describe an experimental scheme for studying recombination that should be applicable to any recombinogenic viruses amenable to the production of synthetic infectious genomes. Our approach is based on differences in fitness that generally exist between synthetic chimaeric genomes and the wild-type viruses from which they are constructed. In mixed infections of defective reciprocal chimaeras, selection strongly favours recombinant progeny genomes that recover a portion of wild-type fitness. Characterizing these evolved progeny viruses can highlight both important genetic fitness determinants and the contribution that recombination makes to the evolution of their natural relatives. Moreover, these experiments supply precise information about the frequency and distribution of recombination breakpoints, which can shed light on the mechanistic processes underlying recombination. We demonstrate the value of this approach using the small single-stranded DNA geminivirus, maize streak virus (MSV). Our results show that adaptive recombination in this virus is extremely efficient and can yield complex progeny genomes comprising up to 18 recombination breakpoints. The patterns of recombination that we observe strongly imply that the mechanistic processes underlying rolling circle replication are the prime determinants of recombination breakpoint distributions found in MSV genomes sampled from nature
Selective Segmental Pulmonary Angiography: Anatomical, Technical and Safety Aspects of a Must-Learn Technique in Times of Balloon Pulmonary Angioplasty for Chronic Thromboembolic Pulmonary Hypertension
With the advent of balloon pulmonary angioplasty (BPA) for non-surgical chronic thromboembolic pulmonary hypertension (CTEPH) patients, there is renewed interest in the pulmonary angiography technique. This technique is still the standard imaging modality to confirm CTEPH, which, in addition, helps to determine the most appropriate treatment. Furthermore, learning this technique fulfills two main purposes: to identify BPA candidates and to provide the operator with the catheter handling needed to perform BPA. Operators interested in performing BPA must learn not only the pulmonary arteriesâ anatomy, but also which are the best angiographic projections and the most suitable catheters to canalize and display each segmental branch. Unfortunately, this information is scarce in the literature. With this goal, learning the diagnostic pulmonary angiography technique can be a first step on the way to perform BPA. Although there are descriptions on how to perform a pulmonary angiography with balloon-tipped catheters and the digital subtraction technique, this technique does not provide operators with the catheter knowledge and manual skill needed to cannulate each segmental branch. In contrast, learning the conventional selective segmental pulmonary angiography (SSPA) technique provides the operator with this knowledge and skills. In this review, based on the experience of the authors, we describe the pulmonary arteriesâ anatomy and detail the practical aspects of the SSPA procedure, with the aim of providing operators with the anatomical and technical knowledge needed to perform BPA. We also summarize the contemporary complications of SSPA in CTEPH patients at a reference center
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