266 research outputs found

    Las cuevas de la Sierra de Atapuerca y el uso humano del paisaje kárstico durante el Pleistoceno (Burgos, España)

    Get PDF
    El karst de la Sierra de Atapuerca representa un interesante sistema multinivel, inactivo y heredado de antiguos niveles de base plio-pleistocenos, que alberga los enclaves prehistóricos más importantes para el conocimiento del poblamiento antiguo en Eurasia, y que fue declarado Patrimonio de la Humanidad en 2000 por la UNESCO. Estas cuevas se originan a partir de conductos subhorizontales con paleodrenajes en sentido SN, localizándose la zona de descarga en la cabecera del río Pico. Los conductos están organizados en tres niveles principales que aparecen colgados entre 90 y 60 m sobre el actual cauce del río Arlanzón, coincidiendo con los niveles de base generados por sus terrazas fluviales T2, T3 y T5. La incisión fluvial liberó de las aguas los conductos superiores mientras se excavaban los niveles inferiores del karst. Las cuevas que iban quedando accesibles fueron utilizadas por la fauna y los homininos, conservando un registro arqueo-paleontológico de más de 1,2 Ma

    Introduciendo el profesionalismo médico en etapas precoces del currículo de medicina: un curso para alumnos de primer año del Grado de Medicina

    Get PDF
    a adquisición de valores y actitudes es un aspecto esencial de los resultados del aprendizaje de los estudiantes de medicina junto con los conocimientos y las habilidades prácticas y forma parte de lo que se conoce como profesionalis- mo médico. El proceso de aprendizaje de un médico implica no sólo el desarrollo de conocimientos y habilidades, sino también un proceso de transformación del alumno en el transcurso del cual aprende a ser diferente y a ser capaz de inte- grarse en una comunidad profesional. Por ello, debe considerarse seriamente la formación de nuestros estudiantes en este campo. Esta formación debe ser un proceso continuo y desde los primeros momentos del Grado de Medicina. En el contexto de la reforma de Bolonia, la Facultad de Medicina de la Universitat de Barcelona y otras facultades de medicina españolas han de nido sus resultados de aprendizaje. Entre ellos, gura que los estudiantes deben ser capaces de aplicar los valores profesionales de excelencia como altruismo, compromiso, responsabilidad, integridad y honestidad en la prác- tica médica. Sin embargo, esta temática no está su cientemente representada en las actividades de aprendizaje del plan de estudios. Por ello, hace seis años, decidimos implementar un curso introductorio sobre profesionalismo médico dirigi- do a estudiantes de primer curso de medicina. En este trabajo describimos nuestra experiencia durante esos años. Los re- sultados de esta experiencia indican que la introducción del profesionalismo desde momentos iniciales del Grado de Me- dicina es factible y altamente apreciado por los estudiantes. Palabras clave. Grado de Medicina. Profesionalismo. Introducing medical professionalism in early moments of the medical curriculum: a course for rst year's medical students Summary. The acquisition of values and attitudes is an essential aspect of the learning outcomes of medical students together with knowledge and practical skills and they are part of what is known as medical professionalism. The learning process of a physician implies not only the development of knowledge and skills but also a transformational process of the learner, whereby he/she also learns to be di erent and to be able to join a professional community. Therefore we need to consider seriously the training of our students in this eld. This training must be a continuous and on-going process throughout the entire educational continuum, beginning from early moments in medical school. In the context of the Bologna reform the Medical School of the University of Barcelona, and other Spanish medical schools, have de ned their learning outcomes. Among them, the students must be able to apply the professional values of excellence, altruism, commitment, responsibility, integrity and honesty in medical practice, but this topic is insu ciently represented in the curriculum learning activities. Consequently six years ago, we decided to implement an introductory course on medical professionalism addressed to rst year medical students. We describe our experience during the last six years of the implementation and development of this introductory course. Our results indicate that the introduction of professionalism from the earliest moments of the educative process in medical schools is feasible and is highly appreciated by our students. Key words. Professionalism. Undergraduate medical curriculum

    Gate-tuneable and chirality-dependent charge-to-spin conversion in tellurium nanowires

    Get PDF
    Chiral materials are an ideal playground for exploring the relation between symmetry, relativistic effects and electronic transport. For instance, chiral organic molecules have been intensively studied to electrically generate spin-polarized currents in the last decade, but their poor electronic conductivity limits their potential for applications. Conversely, chiral inorganic materials such as tellurium have excellent electrical conductivity, but their potential for enabling the electrical control of spin polarization in devices remains unclear. Here, we demonstrate the all-electrical generation, manipulation and detection of spin polarization in chiral single-crystalline tellurium nanowires. By recording a large (up to 7%) and chirality-dependent unidirectional magnetoresistance, we show that the orientation of the electrically generated spin polarization is determined by the nanowire handedness and uniquely follows the current direction, while its magnitude can be manipulated by an electrostatic gate. Our results pave the way for the development of magnet-free chirality-based spintronic devices.This work is supported by the Spanish Ministerio de Ciencia e Innovación (MICINN) under projects RTI2018-094861-B-100 and PID2019-108153GA-I00 and under the Maria de Maeztu Units of Excellence Programme (MDM-2016-0618); by the European Union Horizon 2020 under the Marie Slodowska-Curie Actions (0766025-QuESTech and 892983-SPECTER); and by Intel Corporation under ‘FEINMAN’ and ‘VALLEYTRONICS’ Intel Science Technology Centers. B.M.-G. acknowledges support from the Gipuzkoa Council (Spain) in the frame of the Gipuzkoa Fellows Program. M.S.-R. acknowledges support from La Caixa Foundation (no. 100010434) with code LCF/BQ/DR21/11880030. M.G. acknowledges support from La Caixa Foundation (no. 100010434) for a Junior Leader fellowship (grant no. LCF/BQ/PI19/11690017). A.J. acknowledges support from CRC/TRR 227 of Deutsche Forschungsgemeinschaft.Peer reviewe

    Genomic characterization of individuals presenting extreme phenotypes of high and low risk to develop tobacco-induced lung cancer

    Get PDF
    Single nucleotide polymorphisms (SNPs) may modulate individual susceptibility to carcinogens. We designed a genome-wide association study to characterize individuals presenting extreme phenotypes of high and low risk to develop tobacco-induced non-small cell lung cancer (NSCLC), and we validated our results. We hypothesized that this strategy would enrich the frequencies of the alleles that contribute to the observed traits. We genotyped 2.37 million SNPs in 95 extreme phenotype individuals, that is: heavy smokers that either developed NSCLC at an early age (extreme cases); or did not present NSCLC at an advanced age (extreme controls), selected from a discovery set (n=3631). We validated significant SNPs in 133 additional subjects with extreme phenotypes selected from databases including >39,000 individuals. Two SNPs were validated: rs12660420 (p(combined)=5.66x10(-5); ORcombined=2.80), mapping to a noncoding transcript exon of PDE10A; and rs6835978 (p(combined)=1.02x10(-4); ORcombined=2.57), an intronic variant in ATP10D. We assessed the relevance of both proteins in early-stage NSCLC. PDE10A and ATP10D mRNA expressions correlated with survival in 821 stage I-II NSCLC patients (p=0.01 and p<0.0001). PDE10A protein expression correlated with survival in 149 patients with stage I-II NSCLC (p=0.002). In conclusion, we validated two variants associated with extreme phenotypes of high and low risk of developing tobacco-induced NSCLC. Our findings may allow to identify individuals presenting high and low risk to develop tobacco-induced NSCLC and to characterize molecular mechanisms of carcinogenesis and resistance to develop NSCLC

    All-particle cosmic ray energy spectrum measured by the HAWC experiment from 10 to 500 TeV

    Full text link
    We report on the measurement of the all-particle cosmic ray energy spectrum with the High Altitude Water Cherenkov (HAWC) Observatory in the energy range 10 to 500 TeV. HAWC is a ground based air-shower array deployed on the slopes of Volcan Sierra Negra in the state of Puebla, Mexico, and is sensitive to gamma rays and cosmic rays at TeV energies. The data used in this work were taken from 234 days between June 2016 to February 2017. The primary cosmic-ray energy is determined with a maximum likelihood approach using the particle density as a function of distance to the shower core. Introducing quality cuts to isolate events with shower cores landing on the array, the reconstructed energy distribution is unfolded iteratively. The measured all-particle spectrum is consistent with a broken power law with an index of 2.49±0.01-2.49\pm0.01 prior to a break at (45.7±0.1(45.7\pm0.1) TeV, followed by an index of 2.71±0.01-2.71\pm0.01. The spectrum also respresents a single measurement that spans the energy range between direct detection and ground based experiments. As a verification of the detector response, the energy scale and angular resolution are validated by observation of the cosmic ray Moon shadow's dependence on energy.Comment: 16 pages, 11 figures, 4 tables, submission to Physical Review

    Constraining the pˉ/p\bar{p}/p Ratio in TeV Cosmic Rays with Observations of the Moon Shadow by HAWC

    Get PDF
    An indirect measurement of the antiproton flux in cosmic rays is possible as the particles undergo deflection by the geomagnetic field. This effect can be measured by studying the deficit in the flux, or shadow, created by the Moon as it absorbs cosmic rays that are headed towards the Earth. The shadow is displaced from the actual position of the Moon due to geomagnetic deflection, which is a function of the energy and charge of the cosmic rays. The displacement provides a natural tool for momentum/charge discrimination that can be used to study the composition of cosmic rays. Using 33 months of data comprising more than 80 billion cosmic rays measured by the High Altitude Water Cherenkov (HAWC) observatory, we have analyzed the Moon shadow to search for TeV antiprotons in cosmic rays. We present our first upper limits on the pˉ/p\bar{p}/p fraction, which in the absence of any direct measurements, provide the tightest available constraints of 1%\sim1\% on the antiproton fraction for energies between 1 and 10 TeV.Comment: 10 pages, 5 figures. Accepted by Physical Review
    corecore