4,256 research outputs found

    Corrigendum. Maars to calderas: end-members on a spectrum of explosive volcanic depressions

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    A corrigendum on Maars to calderas: end-members on a spectrum of explosive volcanic depressions by Palladino, D. M., Valentine, G. A., Sottili, G., and Taddeucci, J. (2015). Front. Earth Sci. 3:36. doi: 10.3389/feart.2015.00036 Reason for Corrigendum: In the original article (Palladino et al., 2015), there was an error in Figure 1. The vertical axis of the qualitative plot reported erroneously “ratio of juvenile to lithic materials in deposits outside of depression”. The correct wording is as follows: “ratio of juvenile to total (i.e., juvenile+lithic) materials in deposits outside of depression”. In fact, as it was reported correctly in the text, the amount of juvenilematerial (i.e., scoria or pumice) deposited ouside the different types of explosive volcanic depressions increases from zero (i.e., no juvenile, all lithic products), as is the case of hydrothermal (phreatic) explosion craters, to become largely dominant over the lithic component in the case of ash flow deposits associated with large overpressure collapse calderas. The corrected Figure 1 appears below. The authors apologize for this error and state that this does not change the scientific conclusions of the article in any way

    Neutrino telescopes and high-energy cosmic neutrinos

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    In this review paper, we present the main aspects of high-energy cosmic neutrino astrophysics. We begin by describing the generic expectations for cosmic neutrinos, including the effects of propagation from their sources to the detectors. Then we introduce the operating principles of current neutrino telescopes, and examine the main features (topologies) of the observable events. After a discussion of the main background processes, due to the concomitant presence of secondary particles produced in the terrestrial atmosphere by cosmic rays, we summarize the current status of the observations with astrophysical relevance that have been greatly contributed by IceCube detector. Then, we examine various interpretations of these findings, trying to assess the best candidate sources of cosmic neutrinos. We conclude with a brief perspective on how the field could evolve within a few years

    Mars Regolith Simulant Ameliorated by Compost as In Situ Cultivation Substrate Improves Lettuce Growth and Nutritional Aspects

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    Heavy payloads in future shuttle journeys to Mars present limiting factors, making self-sustenance essential for future colonies. Therefore, in situ resources utilization (ISRU) is the path to successful and feasible space voyages. This research frames the concept of planting leafy vegetables on Mars regolith simulant, ameliorating this substrate’s fertility by the addition of organic residues produced in situ. For this purpose, two butterhead lettuce (Lactuca sativa L. var. capitata) cultivars (green and red Salanova®) were chosen to be cultivated in four dierent mixtures of MMS-1 Mojave Mars simulant:compost (0:100, 30:70, 70:30 and 100:0; v:v) in a phytotron open gas exchange growth chamber. The impact of compost rate on both crop performance and the nutritive value of green- and red-pigmented cultivars was assessed. The 30:70 mixture proved to be optimal in terms of crop performance, photosynthetic activity, intrinsic water use eciency and quality traits of lettuce. In particular, red Salanova® showed the best performance in terms of these quality traits, registering 32% more phenolic content in comparison to 100% simulant. Nonetheless, the 70:30 mixture represents a more realistic scenario when taking into consideration the sustainable use of compost as a limited resource in space farming, while still accepting a slight significant decline in yield and quality in comparison to the 30:70 mixture

    Cosmic Microwave Background Temperature at Galaxy Clusters

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    We have deduced the cosmic microwave background (CMB) temperature in the Coma cluster (A1656, z=0.0231z=0.0231), and in A2163 (z=0.203z=0.203) from spectral measurements of the Sunyaev-Zel'dovich (SZ) effect over four passbands at radio and microwave frequencies. The resulting temperatures at these redshifts are TComa=2.7890.065+0.080T_{Coma} = 2.789^{+0.080}_{-0.065} K and TA2163=3.3770.102+0.101T_{A2163} = 3.377^{+0.101}_{-0.102} K, respectively. These values confirm the expected relation T(z)=T0(1+z)T(z)=T_{0}(1+z), where T0=2.725±0.002T_{0}= 2.725 \pm 0.002 K is the value measured by the COBE/FIRAS experiment. Alternative scaling relations that are conjectured in non-standard cosmologies can be constrained by the data; for example, if T(z)=T0(1+z)1aT(z) = T_{0}(1+z)^{1-a} or T(z)=T0[1+(1+d)z]T(z)=T_{0}[1+(1+d)z], then a=0.160.32+0.34a=-0.16^{+0.34}_{-0.32} and d=0.17±0.36d = 0.17 \pm 0.36 (at 95% confidence). We briefly discuss future prospects for more precise SZ measurements of T(z)T(z) at higher redshifts.Comment: 13 pages, 1 figure, ApJL accepted for publicatio

    Triple Experiment Spectrum of the Sunyaev-Zeldovich Effect in the Coma Cluster: H_0

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    The Sunyaev-Zeldovich (SZ) effect was previously measured in the Coma cluster by the Owens Valley Radio Observatory and Millimeter and IR Testa Grigia Observatory experiments and recently also with the Wilkinson Microwave Anisotropy Probe satellite. We assess the consistency of these results and their implications on the feasibility of high-frequency SZ work with ground-based telescopes. The unique data set from the combined measurements at six frequency bands is jointly analyzed, resulting in a best-fit value for the Thomson optical depth at the cluster center, tau_{0}=(5.35 \pm 0.67) 10^{-3}. The combined X-ray and SZ determined properties of the gas are used to determine the Hubble constant. For isothermal gas with a \beta density profile we derive H_0 = 84 \pm 26 km/(s\cdot Mpc); the (1\sigma) error includes only observational SZ and X-ray uncertainties.Comment: 11 pages, 1 figur

    Telematic solutions in plastic surgery during COVID-19 pandemic: Liability issues and risk management

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    During the COVID-19 pandemic, surgical elective procedures were stopped in our plastic surgery unit. Limitations for consultations and for follow-up of previous surgical procedures were imposed in order to minimize the risk of contagion in waiting rooms and outpatient clinics. We have identified telemedicine as an alternative way to follow patients during the lockdown. Nevertheless, we have experienced different difficulties. We have not had the possibility to use a secure teleconferencing software. In our unit we had not technological devices. Surgeons in our department were not able to use remote video technology for patient management. Guidelines for an appropriate selection of patients which could be served via telemedicine had to be created.Telemedicine must be regulated by healthcare organizations for legal, ethical, medico-legal and risk management aspects.Even if we have experienced an important need to use telematic solutions during the COVID-19 lockdown, liability and risk management issues has greatly limited this possibility in our unit. The need of telemedicine in the time of COVID-19 pandemic has encouraged us to implement future virtual encounters in order to reduce unnecessary in-person visits by taking into consideration all legal, ethical and medico-legal aspects

    CHANTI: a Fast and Efficient Charged Particle Veto Detector for the NA62 Experiment at CERN

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    The design, construction and test of a charged particle detector made of scintillation counters read by Silicon Photomultipliers (SiPM) is described. The detector, which operates in vacuum and is used as a veto counter in the NA62 experiment at CERN, has a single channel time resolution of 1.14 ns, a spatial resolution of ~2.5 mm and an efficiency very close to 1 for penetrating charged particles

    A prototype large-angle photon veto detector for the P326 experiment at CERN

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    The P326 experiment at the CERN SPS has been proposed with the purpose of measuring the branching ratio for the decay K^+ \to \pi^+ \nu \bar{\nu} to within 10%. The photon veto system must provide a rejection factor of 10^8 for \pi^0 decays. We have explored two designs for the large-angle veto detectors, one based on scintillating tiles and the other using scintillating fibers. We have constructed a prototype module based on the fiber solution and evaluated its performance using low-energy electron beams from the Frascati Beam-Test Facility. For comparison, we have also tested a tile prototype constructed for the CKM experiment, as well as lead-glass modules from the OPAL electromagnetic barrel calorimeter. We present results on the linearity, energy resolution, and time resolution obtained with the fiber prototype, and compare the detection efficiency for electrons obtained with all three instruments.Comment: 8 pages, 9 figures, 2 tables. Presented at the 2007 IEEE Nuclear Science Symposium, Honolulu HI, USA, 28 October - 3 November 200

    MELK expression correlates with tumor mitotic activity but is not required for cancer growth

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    The Maternal Embryonic Leucine Zipper Kinase (MELK) has been identified as a promising therapeutic target in multiple cancer types. MELK over-expression is associated with aggressive disease, and MELK has been implicated in numerous cancer-related processes, including chemotherapy resistance, stem cell renewal, and tumor growth. Previously, we established that triple-negative breast cancer cell lines harboring CRISPR/Cas9-induced null mutations in MELK proliferate at wild-type levels in vitro (Lin et al., 2017). Here, we generate several additional knockout clones of MELK and demonstrate that across cancer types, cells lacking MELK exhibit wild-type growth in vitro, under environmental stress, in the presence of cytotoxic chemotherapies, and in vivo. By combining our MELK-knockout clones with a recently described, highly specific MELK inhibitor, we further demonstrate that the acute inhibition of MELK results in no specific anti-proliferative phenotype. Analysis of gene expression data from cohorts of cancer patients identifies MELK expression as a correlate of tumor mitotic activity, explaining its association with poor clinical prognosis. In total, our results demonstrate the power of CRISPR/Cas9-based genetic approaches to investigate cancer drug targets, and call into question the rationale for treating patients with anti-MELK monotherapies
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