280 research outputs found

    Undecidability as solution to the problem of measurement: fundamental criterion for the production of events

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    In recent papers we put forth a new interpretation of quantum mechanics, colloquially known as ``the Montevideo interpretation''. This interpretation is based on taking into account fundamental limits that gravity imposes on the measurement process. As a consequence one has that situations develop where a reduction process is undecidable from an evolution operator. When such a situation is achieved, an event has taken place. In this paper we sharpen the definition of when and how events occur, more precisely we give sufficient conditions for the occurrence of events. We probe the new definition in an example. In particular we show that the concept of undecidability used is not ``FAPP'' (for all practical purposes), but fundamental.Comment: 10 pages, contributed to the Castagnino Festschrif

    A realist interpretation of quantum mechanics based on undecidability due to gravity

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    We summarize several recent developments suggesting that solving the problem of time in quantum gravity leads to a solution of the measurement problem in quantum mechanics. This approach has been informally called "the Montevideo interpretation". In particular we discuss why definitions in this approach are not "for all practical purposes" (fapp) and how the problem of outcomes is resolved.Comment: 7 pages, IOPAMS style, no figures, contributed to the proceedings of DICE 2010, Castiglioncello, slightly improved versio

    Aprendizaje basado en problemas en Biología Vegetal

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    El aprendizaje basado en problemas (ABP) es un método de enseñanzaaprendizaje que usa el problema como punto de partida para la adquisición e integración de nuevos conocimientos. En el desarrollo del ABP el problema es el camino para que los estudiantes alcancen los objetivos de conocimientos, destrezas y habilidades. El ABP y el estudio de casos se centran en el estudiante lo cual implica necesariamente un cambio de función en el profesor que deja de ser protagonista para convertirse en una guía o en tutor. El tutor plantea problemas y cuestiones que contribuyen al entendimiento y a la resolución de problemas promoviendo de esta forma un aprendizaje significativo. Por otra parte, las nuevas tecnologías de la información y la comunicación introducen cambios importantes en el proceso de enseñanza-aprendizaje en base a lo siguiente: a) el acceso a la información y el modo de adquirir información, b) las nuevas formas de relación profesor-alumno. Este trabajo muestra algunas experiencias para el desarrollo de ABP, el estudio de casos y la elaboración de mapas conceptuales e infografías, experiencias realizadas en el aula con estudiantes de Biología de la Universidad Complutense de Madrid y en relación con dos campos de la Biología: la Fisiología Vegetal y la Biología Evolutiva.The problem-based learning (PBL) is a teaching-learning method that uses the problem as a starting point for the acquisition and integration of new knowledge. In the development of PBL the problem is the way to achieve the knowledge, skills and abilities. Problem-based learning and case study focuses on the student and therefore imply a change in the teacher role: from protagonist to tutor or guide. A tutor offers questions that contribute to understanding and managing the problem promoting meaningful learning. On the other hand, information and communication technologies introduces important changes in teaching and learning on the basis of two issues: a) access and how to acquire information, b) new forms of teacher-student relationship. This work shows some experiences for the development of PBL, case studies and concept mapping as classroom experiences for Biological Sciences students at the Complutense University of Madrid. Two biological sciences fields were considered: plant physiology and evolutionary plant biology

    Contribution of autochthonous maize populations for adaptation to European conditions

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    Early vigor, earliness and cold tolerance are the main potential contributions of European maize (Zea mays L.) for breeding programs for adaptation to areas with short growing seasons and cold springs. The objective of this research was to determine the potential contributions of populations from different European regions to breeding for adaptation. Six Spanish and six French maize populations differing on variability for earliness, vigor and cold tolerance were crossed in a complete diallel without reciprocals. The populations and their crosses were evaluated in the field and in a cold chamber. Minimum temperatures were the main environmental trait affecting genotype × environment interaction, probably due to the cold sensitivity of the genotypes with the best performance in the field. The best population cross, based on specific heterosis for adaptation-related traits in the field, was Viana × Rastrojero, but this cross was cold sensitive. Tuy × Lazcano should be the best choice for a breeding program for adaptation, based on performance in the field and cold tolerance. As conclusions, there was variability for earliness, vigor and cold tolerance among the populations and crosses involved in this study, being tolerant to cold conditions the populations with medium growing cycle originated in areas with short growing seasons. The highest yielding crosses were cold sensitive.Research supported by the Ministry of Science and Technology (Ref. HF1999-0138), the Ministère de l’Education Nationale et de la Recherche, the Committee for Science and Technology of Spain (Project AGL2004-06776), the Autonomous government of Galicia (PGIDIT04RAG403006PR), the Excma. Diputación Provincial de Pontevedra, and the European Union (RESGEN 88 CT96).Peer reviewe

    Physical properties of Lyman-alpha emitters at z0.3z\sim 0.3 from UV-to-FIR measurements

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    The analysis of the physical properties of low-redshift Lyα\alpha emitters (LAEs) can provide clues in the study of their high-redshift analogues. At z0.3z \sim 0.3, LAEs are bright enough to be detected over almost the entire electromagnetic spectrum and it is possible to carry out a more precise and complete study than at higher redshifts. In this study, we examine the UV and IR emission, dust attenuation, SFR and morphology of a sample of 23 GALEX-discovered star-forming (SF) LAEs at z0.3z \sim 0.3 with direct UV (GALEX), optical (ACS) and FIR (PACS and MIPS) data. Using the same UV and IR limiting luminosities, we find that LAEs at z0.3z\sim 0.3 tend to be less dusty, have slightly higher total SFRs, have bluer UV continuum slopes, and are much smaller than other galaxies that do not exhibit Lyα\alpha emission in their spectrum (non-LAEs). These results suggest that at z0.3z \sim 0.3 Lyα\alpha photons tend to escape from small galaxies with low dust attenuation. Regarding their morphology, LAEs belong to Irr/merger classes, unlike non-LAEs. Size and morphology represent the most noticeable difference between LAEs and non-LAEs at z0.3z \sim 0.3. Furthermore, the comparison of our results with those obtained at higher redshifts indicates that either the Lyα\alpha technique picks up different kind of galaxies at different redshifts or that the physical properties of LAEs are evolving with redshift.Comment: Accepted for publication in Ap

    PACS-Herschel FIR detections of Lyman-alpha emitters at 2.0<z<3.5

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    In this work we analyze the physical properties of a sample of 56 spectroscopically selected star-forming (SF) Lyα\alpha emitting galaxies at 2.0\lesssimz\lesssim3.5 using both a spectral energy distribution (SED) fitting procedure from rest-frame UV to mid-IR and direct 160μ\mum observations taken with the Photodetector Array Camera & Spectrometer (PACS) instrument onboard \emph{Herschel Space Observatory}. We define LAEs as those Lyα\alpha emitting galaxies whose rest-frame Lyα\alpha equivalent widths (Lyα\alpha EWrestframe_{rest-frame}) are above 20\AA, the typical threshold in narrow-band searches. Lyα\alpha emitting galaxies with Lyα\alpha EWrestframe_{rest-frame} are called non-LAEs. As a result of an individual SED fitting for each object, we find that the studied sample of LAEs contains galaxies with ages mostly below 100Myr and a wide variety of dust attenuations, SFRs, and stellar masses. The heterogeneity in the physical properties is also seen in the morphology, ranging from bulge-like galaxies to highly clumpy systems. In this way, we find that LAEs at 2.0\lesssimz\lesssim3.5 are very diverse, and do not have a bimodal nature, as suggested in previous works. Furthermore, the main difference between LAEs and non-LAEs is their dust attenuation, because LAEs are not as dusty as non-LAEs. On the FIR side, four galaxies of the sample (two LAEs and two non-LAEs) have PACS-FIR counterparts. Their total IR luminosity place all of them in the ULIRG regime and are all dusty objects, with A1200_{1200}\gtrsim4mag. This is an indication from direct FIR measurements that dust and Lyα\alpha emission are not mutually exclusive. This population of red and dusty LAEs is not seen at z\sim0.3, suggesting an evolution with redshift of the IR nature of galaxies selected via their Lyα\alpha emission.Comment: Accepted for publication in A&

    Un nuevo concepto de la gastronomía desde la bioeconomía y la actividad académica

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    El proyecto “Ciencia y arte en gastronomía: botánica gastronómica y gastronomía molecular” se está desarrollando con el objetivo de establecer y organizar el intercambio de conocimientos y negocio en este ámbito. Con este objetivo se pretende aunar el conocimiento científico con la salud y el bienestar social desde la perspectiva bioeconómica promoviendo la creación de riqueza y trabajo. El proyecto forma parte de los cursos especializados que la Universidad Complutense de Madrid oferta con el animo de incrementar el conocimiento y desarrollar competencias personales y profesionales. El programa responde a la demanda social proporcionando una formación con inmediata proyección profesional mediante el establecimiento de un nexo directo entre la actividad académica y la realidad social.Universidad de Sevilla. Cristalografía, Mineralogía y Química Agrícola The project "Science and art in gastronomy: gastronomic botany and molecular gastronomy" is being developed with the aim to establish and organize the exchange of knowledge and business in this area. In this way we are working to join the scientific knowledge to the health and the social well-being, without losing the current perspective from the bioeconomy which look forward the generation of wealth and work. The project belongs to specialized courses offered by The Complutense University of Madrid which aim is to update the knowledge and develop personal and professional competitions. These programs answer to a social demand on providing formation with professional immediate projection establishing a direct relation between the academic activity and the social reality

    Loop Quantum Cosmology: A Status Report

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    The goal of this article is to provide an overview of the current state of the art in loop quantum cosmology for three sets of audiences: young researchers interested in entering this area; the quantum gravity community in general; and, cosmologists who wish to apply loop quantum cosmology to probe modifications in the standard paradigm of the early universe. An effort has been made to streamline the material so that, as described at the end of section I, each of these communities can read only the sections they are most interested in, without a loss of continuity.Comment: 138 pages, 15 figures. Invited Topical Review, To appear in Classical and Quantum Gravity. Typos corrected, clarifications and references adde

    Gemini Observations of Galaxies in Rich Early Environments (GOGREEN) I : survey description.

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    We describe a new Large Program in progress on the Gemini North and South telescopes: Gemini Observations of Galaxies in Rich Early Environments (GOGREEN). This is an imaging and deep spectroscopic survey of 21 galaxy systems at 1 10 in halo mass. The scientific objectives include measuring the role of environment in the evolution of low-mass galaxies, and measuring the dynamics and stellar contents of their host haloes. The targets are selected from the SpARCS, SPT, COSMOS, and SXDS surveys, to be the evolutionary counterparts of today's clusters and groups. The new red-sensitive Hamamatsu detectors on GMOS, coupled with the nod-and-shuffle sky subtraction, allow simultaneous wavelength coverage over λ ∼ 0.6–1.05 μm, and this enables a homogeneous and statistically complete redshift survey of galaxies of all types. The spectroscopic sample targets galaxies with AB magnitudes z΄ < 24.25 and [3.6] μm < 22.5, and is therefore statistically complete for stellar masses M* ≳ 1010.3 M⊙, for all galaxy types and over the entire redshift range. Deep, multiwavelength imaging has been acquired over larger fields for most systems, spanning u through K, in addition to deep IRAC imaging at 3.6 μm. The spectroscopy is ∼50 per cent complete as of semester 17A, and we anticipate a final sample of ∼500 new cluster members. Combined with existing spectroscopy on the brighter galaxies from GCLASS, SPT, and other sources, GOGREEN will be a large legacy cluster and field galaxy sample at this redshift that spectroscopically covers a wide range in stellar mass, halo mass, and clustercentric radius

    The risk of lung cancer related to dietary intake of flavonoids

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    It has been hypothesized that flavonoids in foods and beverages may reduce cancer risk through antioxidation, inhibition of inflammation, and other antimutagenic and antiproliferative properties. We examined associations between intake of five flavonoid subclasses (anthocyanidins, flavan-3-ols, flavones, flavonols, flavanones) and lung cancer risk in a population-based case-control study in Montreal, Canada (1,061 cases and 1,425 controls). Flavonoid intake was estimated from a food frequency questionnaire that assessed diet two years prior to diagnosis (cases) or interview (controls). Odds ratios (ORs) and 95% confidence intervals (CIs) were estimated using unconditional logistic regression. Overall, total flavonoid intake was not associated with lung cancer risk, the effect being similar regardless of sex and smoking level. However, low flavonoid intake from food, but not from beverages, was associated with an increased risk. The adjusted ORs (95% CIs) comparing the highest versus the lowest quartiles of intake were 0.63 (0.47-0.85) for total flavonoids, 0.82 (0.61-1.11) for anthocyanidins, 0.67 (0.50-0.90) for flavan-3-ols, 0.68 (0.50-0.93) for flavones, 0.62 (0.45-0.84) for flavonols, and 0.70 (0.53-0.94) for flavanones. An inverse association with total flavone and flavanone intake was observed for squamous cell carcinoma but not adenocarcinoma. In conclusion, low flavonoid intake from food may increase lung cancer risk
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