5,725 research outputs found

    INFN Camera demonstrator for the Cherenkov Telescope Array

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    The Cherenkov Telescope Array is a world-wide project for a new generation of ground-based Cherenkov telescopes of the Imaging class with the aim of exploring the highest energy region of the electromagnetic spectrum. With two planned arrays, one for each hemisphere, it will guarantee a good sky coverage in the energy range from a few tens of GeV to hundreds of TeV, with improved angular resolution and a sensitivity in the TeV energy region better by one order of magnitude than the currently operating arrays. In order to cover this wide energy range, three different telescope types are envisaged, with different mirror sizes and focal plane features. In particular, for the highest energies a possible design is a dual-mirror Schwarzschild-Couder optical scheme, with a compact focal plane. A silicon photomultiplier (SiPM) based camera is being proposed as a solution to match the dimensions of the pixel (angular size of ~ 0.17 degrees). INFN is developing a camera demonstrator made by 9 Photo Sensor Modules (PSMs, 64 pixels each, with total coverage 1/4 of the focal plane) equipped with FBK (Fondazione Bruno Kessler, Italy) Near UltraViolet High Fill factor SiPMs and Front-End Electronics (FEE) based on a Target 7 ASIC, a 16 channels fast sampler (up to 2GS/s) with deep buffer, self-trigger and on-demand digitization capabilities specifically developed for this purpose. The pixel dimensions of 6×66\times6 mm2^2 lead to a very compact design with challenging problems of thermal dissipation. A modular structure, made by copper frames hosting one PSM and the corresponding FEE, has been conceived, with a water cooling system to keep the required working temperature. The actual design, the adopted technical solutions and the achieved results for this demonstrator are presented and discussed.Comment: In Proceedings of the 34th International Cosmic Ray Conference (ICRC2015), The Hague, The Netherlands. All CTA contributions at arXiv:1508.0589

    Emplacement of sandstone intrusions during contractional tectonics

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    Acknowledgments We acknowledge the support of sponsoring companies of Phase 3 of the Sand Injection Research Group (SIRG). We are very grateful to John Waldron and Jessica Ross for the constructive reviews of the manuscript. We also wish to thank and acknowledge the continuing help and access provided by the Bureau of Land Management.Peer reviewedPostprin

    Post-rift sequence architecture and stratigraphy in the Oligo-Miocene Sardinia rift (Western Mediterranean Sea)

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    Rift basins provide important sedimentary archives to reconstruct past tectonic and climatic conditions. Understanding their sedimentary history is, however, largely hampered by the competing influence of tectonic versus climatic forcing. The aim of this study is to comprehend the effects of local to regional tectonic and global climatic/eustatic changes on shallow marine depositional systems in the Sardinia Rift (Western Mediterranean Sea). For this purpose the stratigraphic and depositional relations of a mixed siliciclastic-carbonate ramp at the Porto Torres Basin margin were studied along extensive proximal to distal transects. Three depositional sequences (DS1 to DS3) of late Burdigalian to early Serravallian age have been identified, which are separated by erosional unconformities. Each contains a lower trans- gressive part and an upper regressive part. The former includes shoreface sandstone (DS2) or coral reef (DS3) deposits on the proximal ramp and channelized sheet sandstone (DS1) or basinal mudstone (DS2, DS3) deposits on the distal ramp, typically recording an upsection trend of sediment starvation. The latter is represented by basinward-prograding coralline red algal carbonate wedges due to enhanced shallow water carbonate production rates. In the long term, the depositional evolution from DS1 to DS3 reveals basin margin progradation associated with decreasing siliciclastic supply. Integrated calcareous nannoplankton-foraminiferal-pectinid biostratigraphy links the depositional sequences to third-order sea-level cycles and allows to correlate the erosional unconformities at the top of DS1 and DS2 with the Bur 5/Lan 1 and Lan 2/Ser 1 sequence boundaries. The improved sequence stratigraphic framework enables better regional and global correlations. This shows that rhodalgal carbonate slopes started prograding in the western branch of the Sardinia Rift during the late Burdigalian because (1) of a worldwide bloom of rhodalgal facies, and (2) decreasing tectonic activity at the transition from the syn- rift to the post-rift stage caused a continuous reduction of the siliciclastic sediment input

    School Attendance, Child Labor and Cash Transfers. An Impact Evaluation of PANES

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    In this paper we analyze the impact an emergency social assistance program, PANES, on school attendance and child labour. The program was carried out in Uruguay from April 2005 to December 2007. Specifically, we analyze the effects of the cash transfer component of the plan (Ingreso Ciudadano), and explore potential explanatory channels such as labour market outcomes, income and awareness of conditionalities. This research is based on a panel of successful and unsuccessful applicants to PANES. The first wave uses the administrative records of the program and the second wave is a follow-up survey that was gathered two months after the program ended and was specifically designed to carry out the impact evaluation of the program. In order to check the robustness of our results, we provide evidence based on two different identification strategies: a regression discontinuity approach using data from the second wave of the panel, and a difference-in-difference approach that exploits the longitudinal nature of the collected data. Our results indicate that the program did not affect school attendance or child labour, whether children are considered as one group or are disaggregated by age or sex. We also do not find any impact on household income, which suggests that income substitution does not explain the lack of results in terms of schooling. It therefore appears that either the size of the transfer was not generous enough to promote school attendance or that the determinants of child school attendance are more complex and require complementary interventions. Our results are particularly relevant for understanding of the role of cash transfers in middle-income countries where attendance rates at primary school are already high, and where the main challenge is to keep students in school at the secondary level. The data also allows us to explore the role of conditionalities. Only a small share of households was aware of the school enrolment condition (20%). Conditionalities were announced and are present in other social security programs in Uruguay, but were ultimately not monitored in this case. We did not find the conditionality to have any robust impact (as perceived by the household) on children’s school enrolment.Cash transfer program; Impact evaluation; School attendance, Child labour, Uruguay

    Mangarara Formation: exhumed remnants of a middle Miocene, temperate carbonate, submarine channel-fan system on the eastern margin of Taranaki Basin, New Zealand

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    The middle Miocene Mangarara Formation is a thin (1–60 m), laterally discontinuous unit of moderately to highly calcareous (40–90%) facies of sandy to pure limestone, bioclastic sandstone, and conglomerate that crops out in a few valleys in North Taranaki across the transition from King Country Basin into offshore Taranaki Basin. The unit occurs within hemipelagic (slope) mudstone of Manganui Formation, is stratigraphically associated with redeposited sandstone of Moki Formation, and is overlain by redeposited volcaniclastic sandstone of Mohakatino Formation. The calcareous facies of the Mangarara Formation are interpreted to be mainly mass-emplaced deposits having channelised and sheet-like geometries, sedimentary structures supportive of redeposition, mixed environment fossil associations, and stratigraphic enclosure within bathyal mudrocks and flysch. The carbonate component of the deposits consists mainly of bivalves, larger benthic foraminifers (especially Amphistegina), coralline red algae including rhodoliths (Lithothamnion and Mesophyllum), and bryozoans, a warm-temperate, shallow marine skeletal association. While sediment derivation was partly from an eastern contemporary shelf, the bulk of the skeletal carbonate is inferred to have been sourced from shoal carbonate factories around and upon isolated basement highs (Patea-Tongaporutu High) to the south. The Mangarara sediments were redeposited within slope gullies and broad open submarine channels and lobes in the vicinity of the channel-lobe transition zone of a submarine fan system. Different phases of sediment transport and deposition (lateral-accretion and aggradation stages) are identified in the channel infilling. Dual fan systems likely co-existed, one dominating and predominantly siliciclastic in nature (Moki Formation), and the other infrequent and involving the temperate calcareous deposits of Mangarara Formation. The Mangarara Formation is an outcrop analogue for middle Miocene-age carbonate slope-fan deposits elsewhere in subsurface Taranaki Basin, New Zealand

    Do Cash Transfers Improve Birth Outcomes? Evidence from Matched Vital Statistics, Social Security and Program Data

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    There is limited empirical evidence on whether unrestricted cash social assistance to poor pregnant women improves children’s birth outcomes. Using program administrative micro-data matched to longitudinal vital statistics on the universe of births in Uruguay, we estimate that participation in a generous cash transfer program led to a sizeable 15% reduction in the incidence of low birthweight. Improvements in mother nutrition and a fall in labor supply, out-of-wedlock births and mother’s smoking all appear to contribute to the effect. We conclude that, by improving child health, unrestricted unconditional cash transfers may help break the cycle of intergenerational poverty.

    Impact of the Uruguayan Conditional Cash Transfer Program

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    We analyze the impact of conditional cash payments on school enrollment, child labor and labor supply implemented between 2005 and 2007 to the poorest Uruguayan households. Targeting income discontinuities are not observed around the thresholds to particiConditional cash transfer program, targeting method, propensity score matching
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