73 research outputs found

    Hydraulic properties of ignimbrites: matrix and fracture permeabilities in two pyroclastic flow deposits from Cimino‑Vico volcanoes (Italy)

    Get PDF
    Hydrological properties of ignimbrites are known in detail only for some areas, although these rocks cover large areas with considerable thicknesses in many volcanic regions of the world. This study investigates hydrological properties of two ignimbrites of Latium (Central Italy), different in age, composition, and origin. The dual porosity of the ignimbrites was examined through laboratory tests, pumping tests, and outcrop surveys. The degree of welding, composition, and stratigraphy of the two ignimbrites are the main factors determining their hydrological properties. The two ignimbrites share a low matrix permeability, showing a different fracturing degree. The more welded ignimbrite is characterized by lower porosity of the matrix and higher fracturing degree, while the less welded ignimbrite is characterized by higher porosity of the matrix and lower fracturing degree. Hydraulic conductivity and storage capacity of the highly welded ignimbrite mainly depend on the denser network of discontinuities. The hydraulic conductivity of the younger ignimbrite, less welded, mainly depend on the sparser network of discontinuities and on the layer of unconsolidated coarse pyroclastic deposits at its base, while the storage capacity depends on the more porous matrix. Should the pyroclastic rocks be used as aquifer for water supplies, or, in other cases, as substratum of waste disposal sites, the dual porosity of the ignimbrites must necessarily include different scales of analysis in order to evaluate the role of matrix and fractures on the permeability of rock mass. In any case, the results of laboratory and on-site tests are to be interpreted taking into account the stratigraphy of the ignimbrite

    Second-generation nitazoxanide derivatives: thiazolides are effective inhibitors of the influenza A virus

    Get PDF
    Aim: The only small molecule drugs currently available for treatment of influenza A virus (IAV) are M2 ion channel blockers and sialidase inhibitors. The prototype thiazolide, nitazoxanide, has successfully completed Phase III clinical trials against acute uncomplicated influenza. Results: We report the activity of seventeen thiazolide analogs against A/PuertoRico/8/1934(H1N1), a laboratory-adapted strain of the H1N1 subtype of IAV, in a cell culture-based assay. A total of eight analogs showed IC50s in the range of 0.14–5.0 μM. Additionally a quantitative structure–property relationship study showed high correlation between experimental and predicted activity based on a molecular descriptor set. Conclusion: A range of thiazolides show useful activity against an H1N1 strain of IAV. Further evaluation of these molecules as potential new small molecule therapies is justified

    SWIPE: a bolometric polarimeter for the Large-Scale Polarization Explorer

    Get PDF
    The balloon-borne LSPE mission is optimized to measure the linear polarization of the Cosmic Microwave Background at large angular scales. The Short Wavelength Instrument for the Polarization Explorer (SWIPE) is composed of 3 arrays of multi-mode bolometers cooled at 0.3K, with optical components and filters cryogenically cooled below 4K to reduce the background on the detectors. Polarimetry is achieved by means of large rotating half-wave plates and wire-grid polarizers in front of the arrays. The polarization modulator is the first component of the optical chain, reducing significantly the effect of instrumental polarization. In SWIPE we trade angular resolution for sensitivity. The diameter of the entrance pupil of the refractive telescope is 45 cm, while the field optics is optimized to collect tens of modes for each detector, thus boosting the absorbed power. This approach results in a FWHM resolution of 1.8, 1.5, 1.2 degrees at 95, 145, 245 GHz respectively. The expected performance of the three channels is limited by photon noise, resulting in a final sensitivity around 0.1-0.2 uK per beam, for a 13 days survey covering 25% of the sky.Comment: In press. Copyright 2012 Society of Photo-Optical Instrumentation Engineers. One print or electronic copy may be made for personal use only. Systematic reproduction and distribution, duplication of any material in this paper for a fee or for commercial purposes, or modification of the content of the paper are prohibite

    The Large-Scale Polarization Explorer (LSPE)

    Full text link
    The LSPE is a balloon-borne mission aimed at measuring the polarization of the Cosmic Microwave Background (CMB) at large angular scales, and in particular to constrain the curl component of CMB polarization (B-modes) produced by tensor perturbations generated during cosmic inflation, in the very early universe. Its primary target is to improve the limit on the ratio of tensor to scalar perturbations amplitudes down to r = 0.03, at 99.7% confidence. A second target is to produce wide maps of foreground polarization generated in our Galaxy by synchrotron emission and interstellar dust emission. These will be important to map Galactic magnetic fields and to study the properties of ionized gas and of diffuse interstellar dust in our Galaxy. The mission is optimized for large angular scales, with coarse angular resolution (around 1.5 degrees FWHM), and wide sky coverage (25% of the sky). The payload will fly in a circumpolar long duration balloon mission during the polar night. Using the Earth as a giant solar shield, the instrument will spin in azimuth, observing a large fraction of the northern sky. The payload will host two instruments. An array of coherent polarimeters using cryogenic HEMT amplifiers will survey the sky at 43 and 90 GHz. An array of bolometric polarimeters, using large throughput multi-mode bolometers and rotating Half Wave Plates (HWP), will survey the same sky region in three bands at 95, 145 and 245 GHz. The wide frequency coverage will allow optimal control of the polarized foregrounds, with comparable angular resolution at all frequencies.Comment: In press. Copyright 2012 Society of Photo-Optical Instrumentation Engineers. One print or electronic copy may be made for personal use only. Systematic reproduction and distribution, duplication of any material in this paper for a fee or for commercial purposes, or modification of the content of the paper are prohibite

    Measurement of the Bottom-Strange Meson Mixing Phase in the Full CDF Data Set

    Get PDF
    We report a measurement of the bottom-strange meson mixing phase \beta_s using the time evolution of B0_s -> J/\psi (->\mu+\mu-) \phi (-> K+ K-) decays in which the quark-flavor content of the bottom-strange meson is identified at production. This measurement uses the full data set of proton-antiproton collisions at sqrt(s)= 1.96 TeV collected by the Collider Detector experiment at the Fermilab Tevatron, corresponding to 9.6 fb-1 of integrated luminosity. We report confidence regions in the two-dimensional space of \beta_s and the B0_s decay-width difference \Delta\Gamma_s, and measure \beta_s in [-\pi/2, -1.51] U [-0.06, 0.30] U [1.26, \pi/2] at the 68% confidence level, in agreement with the standard model expectation. Assuming the standard model value of \beta_s, we also determine \Delta\Gamma_s = 0.068 +- 0.026 (stat) +- 0.009 (syst) ps-1 and the mean B0_s lifetime, \tau_s = 1.528 +- 0.019 (stat) +- 0.009 (syst) ps, which are consistent and competitive with determinations by other experiments.Comment: 8 pages, 2 figures, Phys. Rev. Lett 109, 171802 (2012

    Anticipating and addressing event-specific alcohol consumption among adolescents.

    Get PDF
    Background: Various specific events and celebrations are associated with excessive alcohol consumption and related harms. End-of-school celebrations such as Schoolies in Australia are of particular concern given high levels of documented harm among underage and young drinkers. The present study investigated high school students’ expectations of their Schoolies celebrations to inform future interventions to reduce adverse outcomes among members of this vulnerable group and other young people involved in similar rites of passage. Methods: A link to an online survey was distributed via high schools and Schoolies-related websites. The survey included qualitative questions that invited respondents to discuss (i) aspects of Schoolies they were looking forward to most and least and (ii) their perceptions of the likely consequences if they refrained from consuming alcohol during the event. In total, 435 students provided responses. Results: Respondents discussed the role of Schoolies in marking their transition to adulthood. Their comments revealed a cross-temporal focus indicating that Schoolies is simultaneously symbolic of the past, present, and future. Through its ability to enhance social interaction, alcohol was perceived to have a vital role in realising the potential of this event to signify and facilitate this temporal progression. Conclusions: Results suggest interventions that treat Schoolies as an isolated event that occurs in specific locations may fail to appreciate the extent to which these events transcend time for those involved. Instead, harm reduction is likely to involve a reconceptualisation of the event among both participants and authority figures to facilitate the provision of alternative pastimes to drinking during Schoolies that yield similar social benefits

    Guidelines for the use and interpretation of assays for monitoring autophagy (3rd edition)

    Get PDF
    In 2008 we published the first set of guidelines for standardizing research in autophagy. Since then, research on this topic has continued to accelerate, and many new scientists have entered the field. Our knowledge base and relevant new technologies have also been expanding. Accordingly, it is important to update these guidelines for monitoring autophagy in different organisms. Various reviews have described the range of assays that have been used for this purpose. Nevertheless, there continues to be confusion regarding acceptable methods to measure autophagy, especially in multicellular eukaryotes. For example, a key point that needs to be emphasized is that there is a difference between measurements that monitor the numbers or volume of autophagic elements (e.g., autophagosomes or autolysosomes) at any stage of the autophagic process versus those that measure fl ux through the autophagy pathway (i.e., the complete process including the amount and rate of cargo sequestered and degraded). In particular, a block in macroautophagy that results in autophagosome accumulation must be differentiated from stimuli that increase autophagic activity, defi ned as increased autophagy induction coupled with increased delivery to, and degradation within, lysosomes (inmost higher eukaryotes and some protists such as Dictyostelium ) or the vacuole (in plants and fungi). In other words, it is especially important that investigators new to the fi eld understand that the appearance of more autophagosomes does not necessarily equate with more autophagy. In fact, in many cases, autophagosomes accumulate because of a block in trafficking to lysosomes without a concomitant change in autophagosome biogenesis, whereas an increase in autolysosomes may reflect a reduction in degradative activity. It is worth emphasizing here that lysosomal digestion is a stage of autophagy and evaluating its competence is a crucial part of the evaluation of autophagic flux, or complete autophagy. Here, we present a set of guidelines for the selection and interpretation of methods for use by investigators who aim to examine macroautophagy and related processes, as well as for reviewers who need to provide realistic and reasonable critiques of papers that are focused on these processes. These guidelines are not meant to be a formulaic set of rules, because the appropriate assays depend in part on the question being asked and the system being used. In addition, we emphasize that no individual assay is guaranteed to be the most appropriate one in every situation, and we strongly recommend the use of multiple assays to monitor autophagy. Along these lines, because of the potential for pleiotropic effects due to blocking autophagy through genetic manipulation it is imperative to delete or knock down more than one autophagy-related gene. In addition, some individual Atg proteins, or groups of proteins, are involved in other cellular pathways so not all Atg proteins can be used as a specific marker for an autophagic process. In these guidelines, we consider these various methods of assessing autophagy and what information can, or cannot, be obtained from them. Finally, by discussing the merits and limits of particular autophagy assays, we hope to encourage technical innovation in the field

    Inflation and Dark Energy from spectroscopy at z > 2

    Get PDF
    corecore