740 research outputs found

    Relaxion and light (pseudo)scalars at the HL-LHC and lepton colliders

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    We study the potential of future lepton colliders, running at the Z-pole and above, and the High-Luminosity LHC to search for the relaxion and other light scalars ϕ\phi. We investigate the interplay of direct searches and precision observables for both CP-even and -odd couplings. In particular, precision measurements of exotic Z-decays, Higgs couplings, the exotic Higgs decay into a relaxion pair and associated ZϕZ\phi and γϕ\gamma \phi production are promising channels to yield strong bounds.Comment: 27 pages + references, 5 figures, 2 table

    Evidence-based indications for the planning of PET or PET/CT capacities are needed

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    Purpose To identify evidence-based indications for PET/PET–CT scans in support of facilities planning and to describe a pilot project in which this information was applied for an investment decision in an Austrian region. The study updates a Health Technology Assessment (HTA) report (2015) on oncological indications, extending it to neurological indications and inflammatory disorders. Methods A systematic literature search to identify HTA reports, evidence-based guidelines, and systematic reviews/meta-analyses (SR/MA) was performed, supplemented by a manual search for professional society recommendations and explicit “not-to-do’s”. A needs-assessment was conducted in the context of the pilot study on investing in an additional PET–CT scanner in the Austrian region of Carinthia. Results Overall recommendations for indications as well as non-recommendations for the three areas (oncology, neurology, and inflammatory disorders) were compiled from the 2015 PET–HTA report and expanded for a final total of ten HTA, comprising 234 (positive and negative) recommendations from professional societies and databases, and supplemented by findings from 23 SR/MA. For the investment decision pilot study in Carinthia, 1762 PET scans were analyzed; 77.8% were assigned to the category “recommended evidence-based indications” (54.7%), “not recommended” (1.8%) or “contradictory recommendations” (21.3%). The remaining could not be assigned to any of the three categories. Conclusions The piloting of PET capacity planning using evidence-based information is a first of its kind in the published literature. On one hand, the high number of PET scans that could not be ascribed to any of the categories identified limits to the instructive power of the study to use evidence-based indication lists as the basis for a needs-assessment investment planning. On the other hand, this study reveals how there is a need to improve indication coding for enhanced capacity planning of medical services. Overall recommendations identified can serve as needs-based and evidence-based decision support for PET/PET–CT service provision

    Phenomenology of relaxion-Higgs mixing

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    We show that the relaxion generically stops its rolling at a point that breaks CP leading to relaxion-Higgs mixing. This opens the door to a variety of observational probes since the possible relaxion mass spans a broad range from sub-eV to the GeV scale. We derive constraints from current experiments (fifth force, astrophysical and cosmological probes, beam dump, flavour, LEP and LHC) and present projections from future experiments such as NA62, SHiP and PIXIE. We find that a large region of the parameter space is already under the experimental scrutiny. All the experimental constraints we derive are equally applicable for general Higgs portal models. In addition, we show that simple multiaxion (clockwork) UV completions suffer from a mild fine tuning problem, which increases with the number of sites. These results favour a cut-off scale lower than the existing theoretical bounds.Comment: 46 pages, 6 figures, v3: typos fixed, references added, version matches the version published in JHE

    Frictional Duality Observed during Nanoparticle Sliding

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    One of the most fundamental questions in tribology concerns the area dependence of friction at the nanoscale. Here, experiments are presented where the frictional resistance of nanoparticles is measured by pushing them with the tip of an atomic force microscope. We find two coexisting frictional states: While some particles show finite friction increasing linearly with the interface areas of up to 310,000nm^2, other particles assume a state of frictionless sliding. The results further suggest a link between the degree of surface contamination and the occurrence of this duality.Comment: revised versio

    Probing new spin-independent interactions through precision spectroscopy in atoms with few electrons

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    The very high precision of current measurements and theory predictions of spectral lines in few-electron atoms allows us to efficiently probe the existence of exotic forces between electrons, neutrons and protons. We investigate the sensitivity to new spin-independent interactions in transition frequencies (and their isotopic shifts) of hydrogen, helium and some heliumlike ions. We find that present data probe new regions of the force-carrier couplings to electrons and neutrons around the MeV mass range. We also find that, below few keV, the sensitivity to the electron coupling in precision spectroscopy of helium and positronium is comparable to that of the anomalous magnetic moment of the electron. Finally, we interpret our results in the dark-photon model where a new gauge boson is kinetically mixed with the photon. There, we show that helium transitions, combined with the anomalous magnetic moment of the electron, provide the strongest indirect bound from laboratory experiments above 100 keV.United States. Department of Energy (Grant DE-SC0012567

    Effect of loss of CDKL5 on brain development in a new Cdkl5 knockout mouse model

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    Rett's Syndrome (RTT) is a severe neurodevelopmental disorder, characterized by cognitive disability that appears in the first months/years of life. Recently, mutations in the X-linked cyclin-dependent kinase-like 5 (CDKL5) gene have been detected in RTT patients characterized by early-onset seizures. CDKL5 is highly expressed in the brain starting from early postnatal stages to adulthood, suggesting the importance of this kinase for proper brain maturation and function. However, the role/s of CDKL5 in brain development and the molecular mechanisms whereby CDKL5 exerts its effects are still largely unknown. In order to characterize the role of CDKL5 on brain development, we created a mice carrying a targeted conditional knockout allele of Cdkl5. A first behavioral characterization shows that Cdkl5 knockout mice recapitulate several features that mimic the clinical features described in CDKL5 patients and are a useful tool to investigate phenotypic and functional aspects of Cdkl5 loss. We used the Cdkl5 knockout mouse model to dissect the role of CDKL5 on hippocampal development and to establish the mechanism/s underlying its actions. We found that Cdkl5 knockout mice showed increased precursor cell proliferation in the hippocampal dentate gyrus. Interestingly, this region was also characterized by an increased rate of apoptotic cell death that caused a reduction in the final neuron number in spite of the proliferation increase. Moreover, loss of Cdkl5 led to decreased dendritic development of new generated granule cells. Finally, we identified the Akt/GSK3-beta signaling as a target of Cdkl5 in the regulation of neuronal precursor proliferation, survival and maturation. Overall our findings highlight a critical role of CDKL5/AKT/GSK3-beta signaling in the control of neuron proliferation, survival and differentiation and suggest that CDKL5-related alterations of these processes during brain development underlie the neurological symptoms of the CDKL5 variant of RTT

    Patrimonio cultural de Aldea San Antonio. Aportes al desarrollo territorial a través del turismo (Entre Ríos, Argentina)

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    Universidad del Salvador, through its Faculty of History, Geography and Tourism, has been carrying out for several years research work where environment, natural and cultural resources, sustainable development and tourism have been analysed. Several of these works reflected the joint work with some villages in Entre Rios province, Argentina. Particularly, studies in Aldea San Antonio were carried out. It was possible to see the potential of this town from a heritage, cultural and tourist perspective. In this context, the objective of the research was to register and to classify tangible and intangible heritage. And specifically, to develop a cultural tourism circuit based on the opinion of the local community. The project had four phases. The first two were oriented to the survey of secondary sources, the elaboration of research instruments and relevant actors' interviews. The last phases involved the processing of the information collected and the preliminary design of a cultural touristic circuit.La Universidad del Salvador, a través de su Facultad de Historia, Geografía y Turismo, desarrolla desde hace varios años trabajos de investigación que han profundizado en aspectos relativos al medio ambiente, los recursos naturales y culturales, el desarrollo sostenible y el turismo. Varios de estos trabajos reflejan la labor conjunta con algunas localidades de la provincia de Entre Ríos, Argentina. Particularmente, se realizaron estudios en Aldea San Antonio que permitieron constatar el potencial de esta localidad desde la perspectiva patrimonial, cultural y turística. De esta manera el objetivo del proyecto de investigación fue realizar un registro y clasificación del patrimonio tangible e inmaterial, y de manera específica, elaborar una propuesta de circuito turístico basado en el patrimonio cultural que considere la opinión de la comunidad local y contribuya a fortalecer los procesos de desarrollo del territorio. El proyecto comprendió cuatro etapas. Las primeras fases se orientaron al relevamiento de fuentes secundarias, la entrevista a actores clave, la elaboración de instrumentos de registro y sondeo de opinión con su respectiva aplicación a través del trabajo de campo. En las últimas fases se realizó el procesamiento de la información recopilada y el diseño preliminar de un circuito turístico-cultural
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