The PADME experiment at LNF

Massive photon-like particles are predicted in many extensions of the Standard Model. They have interactions similar to the photon, are vector bosons, and can be produced together with photons. The PADME experiment proposes a search for the dark photon ($A'$) in the $e^+e^- \to \gamma A'$ process in a positron-on-target experiment, exploiting the positron beam of the DA$\Phi$NE linac at the Laboratori Nazionali di Frascati, INFN. In one year of running a sensitivity in the relative interaction strength down to $10^{-6}$ is achievable, in the mass region from 2.5 MeV $<M_{A'}<$ 22.5 MeV. The proposed experimental setup and the analysis technique is discussed.Comment: to be published in the DHF2014 proceedings EPJ Web of Conference

Improving application responsiveness with the BFQ disk I/O scheduler

BFQ (Budget Fair Queueing) is a production-quality, proportional-share disk scheduler with a relatively large user base. Part of its success is due to a set of simple heuristics that we added to the original algorithm about one year ago. These heuristics are the main focus of this paper. The first heuristic enriches BFQ with one of the most desirable properties for a desktop or handheld system: responsiveness. The remaining heuristics improve the robustness of BFQ across heterogeneous devices, and help BFQ to preserve a high throughput under demanding workloads. To measure the performance of these heuristics we have implemented a suite of micro and macro benchmarks mimicking several real-world tasks, and have run it on three different systems with a single rotational disk. We have also compared our results against Completely Fair Queueing (CFQ), the default Linux disk scheduler

Towards Design Strategies for Requalifying the Rural: A Comparative Study of Hollow Settlements in China and Italy

Smallsettlementsincountrysideareascallforagrowingnumberofchallengesagainst the backdrop of global rural-urban transition. In this paper, we focus on the processes of depopulation and building abandonment in rural areas of China and Italy. We consider two similar experiences taking place in different contexts, and suggest useful design tools for strategies of architectural requalification. In China, we study a small village in Fujian Province as a paradigmatic example of the well-known phenomenon of “hollow villages.” The word hollow refers to the emptying of dwellings in the central parts of rural settlements, while, paradoxically, their fringe areas are the object of residential land expansion. This notion was coined in the early 1990s to describe the spatial, social and economic consequences of the combination of a rural exodus and a rampant urbanisation. In Italy, we consider a case study in the Province of Trento, where the evacuation of village central cores follow the sprawling towards the village’s outskirts. Even though the recent trends show that the demographic haemorrhage away from the village is declining, the abandonment of old houses in favour of the construction of new ones seems relentless. Such issues gather a growing interest by cultural, political and academic institutions. Never the less, little attention has been paid to the similarities of architectural experiences across national boundaries. Aiming to bridge this gap, we compare the results of our studies on the architectural requalification of rural settlements in both China and Italy. Our methodology embodies a graphic representation of our fieldwork, examines the relationships between the built form and its natural framework and analytically assesses the physical condition and use level of the existing buildings. Despite local specificities, there are significant overlaps from which these and other cases can gain insight. We observe that similar transnational issues can be stimulated by global transition processes driven by local forces and context-related patterns of spatial transformation. More specifically, the intensity and the extent of hollowing of Chinese villages stimulates the broad testing of a spectrum of methodologies and knowledges. These can be both inherited from other contexts or experimented with as innovative approaches. From this perspective, the Italian experience, where the abandonment dates backwards in time, is a fruitful source of comparison

Dose distribution calculation for in-vivo X-ray fluorescence scanning

In-vivo X-ray fluorescence constitutes a useful and accurate technique, worldwide established for constituent elementary distribution assessment. Actually, concentration distributions of arbitrary user-selected elements can be achieved along sample surface with the aim of identifying and simultaneously quantifying every constituent element. The method is based on the use of a collimated X-ray beam reaching the sample. However, one common drawback for considering the application of this technique for routine clinical examinations was the lack of information about associated dose delivery. This work presents a complete study of the dose distribution resulting from an in-vivo X-ray fluorescence scanning for quantifying biohazard materials on human hands. Absorbed dose has been estimated by means of dosimetricmodels specifically developed to this aim. In addition, complete dose distributions have been obtained by means of full radiation transport calculations in based on stochastic Monte Carlo techniques. A dedicated subroutine has been developed using the PENELOPE 2008 main code also integrated with dedicated programs -MatLab supported- for 3D dose distribution visualization. The obtained results show very good agreement between approximate analytical models and full descriptions by means of Monte Carlo simulations.La Fluorescencia de rayos-X in-vivo constituye una técnica útil y precisa, establecida ampliamente para la evaluación de constituyente de distribución primaria. De hecho las distribuciones de concentración de un elemento seleccionado arbitrariamente por el usuario se pueden lograr a lo largo de la superficie de la muestra con el objetivo de identificar y cuantificar simultáneamente cada elemento constituyente. El método se basa en el uso de un haz colimado de rayos X que incide en la muestra. Sin embargo, un inconveniente común para considerar la aplicación de esta técnica para exámenes clínicos de rutina es la falta de información sobre la administración de la dosis correspondiente. Este trabajo presenta un estudio completo de la distribución de la dosis resultante de un barrido in-vivo de Fluorescencia de rayos X para la cuantificacio ́n de los materiales biológicos peligrosos en manos humanas. La dosis absorbida se ha estimado por medio de modelos dosimétricos específicamente desarrollados para este fin. Además, las distribuciones de dosis completas se han obtenido por medio de cálculos de transporte de radiación completo en base a técnicas estocásticas de Monte Carlo. Una subrutina dedicada ha sido desarrollada utilizando el código principal PENELOPE 2008 también integrada con programas dedicados de soporte MatLab para la visualización 3D de la distribución de dosis. Los resultados obtenidos muestran una buena concordancia entre los modelos analíıticos aproximados y en todas las descripciones por medio de simulaciones de Monte Carlo.Fil: Figueroa, Rodolfo. Universidad De La Frontera. Dep de Ciencias Físicas; Chile;Fil: Lozano, Enrique. Instituto Nacional del Cancer. Unidad de Física Médica; Chile;Fil: Valente, Mauro Andres. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico - Conicet - Cordoba. Instituto de Fisica Enrique Gaviola; Argentina

Direct vs 2-stage approaches to structured motif finding

BACKGROUND: The notion of DNA motif is a mathematical abstraction used to model regions of the DNA (known as Transcription Factor Binding Sites, or TFBSs) that are bound by a given Transcription Factor to regulate gene expression or repression. In turn, DNA structured motifs are a mathematical counterpart that models sets of TFBSs that work in concert in the gene regulations processes of higher eukaryotic organisms. Typically, a structured motif is composed of an ordered set of isolated (or simple) motifs, separated by a variable, but somewhat constrained number of “irrelevant” base-pairs. Discovering structured motifs in a set of DNA sequences is a computationally hard problem that has been addressed by a number of authors using either a direct approach, or via the preliminary identification and successive combination of simple motifs. RESULTS: We describe a computational tool, named SISMA, for the de-novo discovery of structured motifs in a set of DNA sequences. SISMA is an exact, enumerative algorithm, meaning that it finds all the motifs conforming to the specifications. It does so in two stages: first it discovers all the possible component simple motifs, then combines them in a way that respects the given constraints. We developed SISMA mainly with the aim of understanding the potential benefits of such a 2-stage approach w.r.t. direct methods. In fact, no 2-stage software was available for the general problem of structured motif discovery, but only a few tools that solved restricted versions of the problem. We evaluated SISMA against other published tools on a comprehensive benchmark made of both synthetic and real biological datasets. In a significant number of cases, SISMA outperformed the competitors, exhibiting a good performance also in most of the cases in which it was inferior. CONCLUSIONS: A reflection on the results obtained lead us to conclude that a 2-stage approach can be implemented with many advantages over direct approaches. Some of these have to do with greater modularity, ease of parallelization, and the possibility to perform adaptive searches of structured motifs. As another consideration, we noted that most hard instances for SISMA were easy to detect in advance. In these cases one may initially opt for a direct method; or, as a viable alternative in most laboratories, one could run both direct and 2-stage tools in parallel, halting the computations when the first halts

Dose point kernel calculation and modelling with nuclear medicine dosimetry purposes

Trabajo presentado en el X Latin American Symposium on Nuclear Physics and Applications (X LASNPA), 1-6 diciembre 2013. Montevideo, Uruguay.Monoclonal labeled antibodies are commonly used for radioimmunotherapy purposes in nuclear medicine. The procedure is based on the deposition of specific radiactivity concentrations on tumoral regions with the aim of treating tumoral diseases. Patient metabolism produces nonuniform organ activity distributions, but there are some traditional approaches for internal dosimetry assuming uniform spatial distribution of activity within organ or tissues of interest. When patient-specific dosimetry needs to be performed, these methods may involve non negligible uncertainties. Treatment evaluation and preliminary planning require the estimation of absorbed dose distribution and this goal can be achieved by different approaches. For example, it is possible to perform Monte Carlo simulations for numerical dose assessments; whereas analytical calculations can be carried out by convolution of activity distribution using Dose Point Kernels. Besides, it is often found that some internal dosimetry approaches assume simplified conditions of infinite ad homogeneous media for radiation transport and corresponding dose deposition. This work presents a method for internal dosimetry in nuclear medicine by means of Dose Point Kernels. The proposed method is capable of performing calculations over heterogeneous systems. The starting point is a set of suitable kernels previously calculated by Monte Carlo simulations in different tissues. Thus, dose distribution is obtained by the proposed hybrid approach involving both numerical and analytical methods. Preliminary tests on simplified geometries demonstrated the capability of the developed technique; whereas computation of patient-specific internal dosimetry suggest promising performance. Hence, the developed method may constitute a valuable tool for nuclear medicine dosimetry purposes.publishedVersionFil: Scarinci, Ignacio Emanuel. Universidad Nacional de Córdoba. Facultad de Matemática, Astronomía y Física. Laboratorio de Investigación e Instrumentación en Física Aplicada a la Medicina e Imágenes por Rayos X; Argentina.Fil: Valente, Mauro Andrés. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Física Enrique Gaviola; Argentina.Fil: Valente, Mauro Andrés. Universidad Nacional de Córdoba. Facultad de Matemática, Astronomía y Física. Laboratorio de Investigación e Instrumentación en Física Aplicada a la Medicina e Imágenes por Rayos X; Argentina.Fil: Pérez, Pedro Antonio. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Física Enrique Gaviola; Argentina.Fil: Pérez, Pedro Antonio. Universidad Nacional de Córdoba. Facultad de Matemática, Astronomía y Física. Laboratorio de Investigación e Instrumentación en Física Aplicada a la Medicina e Imágenes por Rayos X; Argentina.Fil: Pérez, Pedro Antonio. Universidad Nacional de Río Cuarto. Facultad de Ciencias Exactas, Físico-Químicas y Naturales. Departamento de Física; Argentina.Física Atómica, Molecular y Química (física de átomos y moléculas incluyendo colisión, interacción con radiación, resonancia magnética, Moessbauer Efecto.

Internal dosimetry for alpha emitters radiopharmaceuticals in biological tissue studied with the FLUKA code

Trabajo presentado en el X Latin American Symposium on Nuclear Physics and Applications (X LASNPA), 1-6 diciembre 2013. Montevideo, Uruguay.Nuclear medicine clinical practices for neoplasic disease diagnose and treatment are based on the incorporation of α, β and γ radiotracers and radiopharmaceuticals, which might be associated with potential damage. Thus, being necessary accurate dosimetry strategies. In vivo absorbed dose appears as an ideal solution. However, its implementation in clinics does not attain enough reliability. In this sense, different approaches were proposed for internal dosimetry calculations. This work presents a novel analytical-numerical approach for internal dosimetry purposes. Dedicated Monte Carlo simulations were performed by subroutines adapted from the FLUKA code. In-water EDK were evaluated at different photon energies and some typical γ-emitters radiopharmaceuticals; whereas DPK were obtained for both α- and β- emitters. Additionally, EDK and DPK were calculated for several biological tissues.publishedVersionFil: Valente, Mauro Andrés. Universidad Nacional de Córdoba. Facultad de Matemática, Astronomía y Física; Argentina.Fil: Valente, Mauro Andrés. Consejo Nacional de Investigaciones Científicas y Técnica. Instituto de Física Enrique Gaviola; Argentina.Fil: Valente, Mauro Andrés. Universidad Nacional de Córdoba. Laboratorio de Investigación e Instrumentación en Física Aplicada a la Medicina e Imágenes por Rayos X; Argentina.Fil: Malano, Francisco Mauricio. Universidad Nacional de Córdoba. Facultad de Matemática, Astronomía y Física; Argentina.Fil: Malano, Francisco Mauricio. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Física Enrique Gaviola; Argentina.Fil: Malano, Francisco Mauricio. Universidad Nacional de Córdoba. Laboratorio de Investigación e Instrumentación en Física Aplicada a la Medicina e Imágenes por Rayos X; Argentina.Fil: Pérez, Pedro Antonio. Universidad Nacional de Córdoba. Facultad de Matemática, Astronomía y Física; Argentina.Fil: Pérez, Pedro Antonio. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Física Enrique Gaviola; Argentina.Fil: Pérez, Pedro Antonio. Universidad Nacional de Córdoba. Laboratorio de Investigación e Instrumentación en Física Aplicada a la Medicina e Imágenes por Rayos X; Argentina.Física Atómica, Molecular y Química (física de átomos y moléculas incluyendo colisión, interacción con radiación, resonancia magnética, Moessbauer Efecto.

Macrophage inflammatory protein-1alpha mediates matrix metalloproteinase-9 enhancement in human adherent monocytes fed with malarial pigment.

Abstract Objective To investigate the role of macrophage inflammatory protein-1alpha (MIP-1alpha) in the detrimental enhancement of matrix metalloproteinase-9 (MMP-9) expression, release and activity induced by phagocytosis of malarial pigment (haemozoin, HZ) in human monocytes. Methods Human adherent monocytes were unfed/fed with native HZ for 2 h. After 24 hours, MIP-1alpha production was evaluated by ELISA in cell supernatants. Alternatively, HZ-unfed/fed monocytes were treated in presence/absence of anti-human MIP-1alpha blocking antibodies or recombinant human MIP-1alpha for 15 h (RNA studies) or 24 h (protein studies); therefore, MMP-9 mRNA expression was evaluated in cell lysates by Real Time RT-PCR, whereas proMMP-9 and active MMP-9 protein release were measured in cell supernatants by Western blotting and gelatin zymography. Results Phagocytosis of HZ by human monocytes increased production of MIP-1 alpha, mRNA expression of MMP-9 and protein release of proMMP-9 and active MMP-9. All the HZ-enhancing effects on MMP-9 were abrogated by anti-human MIP-1alpha blocking antibodies and mimicked by recombinant human MIP-1alpha. Conclusions The present work suggests a role for MIP-1alpha in the HZ-dependent enhancement of MMP-9 expression, release and activity observed in human monocytes, highlighting new detrimental effects of HZ-triggered proinflammatory response by phagocytic cells in falciparum malaria