4,563 research outputs found

    The upgrade of the ALICE Inner Tracking System

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    The Inner Tracking System (ITS) of the ALICE experiment will be upgraded during the second long LHC shutdown in 20192020\mathrm{2019}-\mathrm{2020}. The main goal of the ALICE ITS Upgrade is to enable high precision measurements of low - momentum particles (< 1 GeV/c) by acquiring a large sample of events, benefiting from the increase of the LHC instantaneous luminosity of PbPb\mathrm{Pb}-\mathrm{Pb} collisions to L=61027cm2s1\mathcal{L} = 6 \cdot 10^{27} cm^{-2} s^{-1} during Run 3. Working in this direction the ITS upgrade project is focusing on the increase of the readout rate, on the improvement of the impact parameter resolution, as well as on the improvement of the tracking efficiency and the position resolution. The major setup modification is the substitution of the current ITS with seven layers of silicon pixel detectors. The ALPIDE chip, a CMOS Monolithic Active Pixel Sensor (MAPS), was developed for this purpose and offers a spatial resolution of 5 μ\mum. The use of MAPS together with a stringent mechanical design allows for the reduction of the material budget down to 0.35% X0X_0 for the innermost layers and 1% X0X_0 for the outer layers. The detector design was validated during the research and development period through a variety of tests ensuring the proper operation for the full lifetime inside ALICE. The production phase is close to completion with all the new assembled components undergoing different tests that aim to characterize the modules and staves and determine their qualification level. This contribution describes the detector design, the measurements performed during the research and development phase, as well as the production status

    Forecasting Exchange-Rates via Local Approximation Methods and Neural Networks

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    There has been an increased number of papers in the literature in recent years, applying several methods and techniques for exchange - rate prediction. This paper focuses on the Greek drachma using daily observations of the drachma rates against four major currencies, namely the U.S. Dollar (USD), the Deutsche Mark (DM), the French Franc (FF) and the British Pound (GBP) for a period of 11 years, aiming at forecasting their short-term course by applying local approximation methods based on both chaotic analysis and neural networks.Key Words: Exchange Rates, Forecasting, Neural Networks

    Напрямки реформування аерокосмічної галузі України в умовах глобалізації

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    Strong selection against heterospecific sex signals, which includes both receivers and signallers, is considered to be the most significant causal factor in animal signal modification and is expected to prevent mate misinterpretation. Using a simultaneous choice bioassay, we tested the continued use of primordial sex signals in distantly related and geographically separated fish species, Pseudorasbora parva and Pimephales promelas. Here, we show that intraspecific selection pressures have not caused significant sex chemical signal differentiation between the 2 species and that mate attraction is likely due to a combination of common ancestry and an absence of divergence in allopatry. In the absence of mate discrimination among species, which have evolved for long periods of time in allopatry, reunification through species translocation could represent an overlooked risk of pheromone pollution

    Understanding the threats posed by non-native species: public vs. conservation managers.

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    Public perception is a key factor influencing current conservation policy. Therefore, it is important to determine the influence of the public, end-users and scientists on the prioritisation of conservation issues and the direct implications for policy makers. Here, we assessed public attitudes and the perception of conservation managers to five non-native species in the UK, with these supplemented by those of an ecosystem user, freshwater anglers. We found that threat perception was not influenced by the volume of scientific research or by the actual threats posed by the specific non-native species. Media interest also reflected public perception and vice versa. Anglers were most concerned with perceived threats to their recreational activities but their concerns did not correspond to the greatest demonstrated ecological threat. The perception of conservation managers was an amalgamation of public and angler opinions but was mismatched to quantified ecological risks of the species. As this suggests that invasive species management in the UK is vulnerable to a knowledge gap, researchers must consider the intrinsic characteristics of their study species to determine whether raising public perception will be effective. The case study of the topmouth gudgeon Pseudorasbora parva reveals that media pressure and political debate has greater capacity to ignite policy changes and impact studies on non-native species than scientific evidence alone

    The changing landscape of OSH regulation in the UK

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    This report presents key findings of a research project on the changing landscape of OSH regulation in the UK. Understanding the changing landscape of OSH regulation and standards and its implications are of central importance for ensuring that OSH outcomes are not compromised and the needs of different types of organisations are met. This project examined the landscape of OSH in the UK since its origin and in particular looked at how regulation of OSH has evolved over time. It considered both policy and practice issues as well as the role of key stakeholders in this process with a view to identify how the right balance can be achieved to promote health and safety going forward. To achieve its aims, a qualitative methodology was implemented in five stages: a. a literature and policy review, including a comparative analysis with other countries; b. case study analysis; c. stakeholder interviews, d. stakeholder workshops including focus groups; and e. research output synthesis

    Consistent patterns of trophic niche specialisation in host populations infected with a non-native copepod parasite.

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    Populations of generalist species often comprise of smaller sub-sets of relatively specialised individuals whose niches comprise small sub-sets of the overall population niche. Here, the role of parasite infections in trophic niche specialisation was tested using five wild fish populations infected with the non-native parasite Ergasilus briani, a copepod parasite with a direct lifecycle that infects the gill tissues of fish hosts. Infected and uninfected fishes were sampled from the same habitats during sampling events. Prevalence in the host populations ranged between 16 and 67 %, with parasite abundances of up to 66 parasites per fish. Although pathological impacts included hyperplasia and localised haemorrhaging of gill tissues, there were no significant differences in the length, weight and condition of infected and uninfected fishes. Stable isotope analyses (δ13C, δ15N) revealed that the trophic niche of infected fishes, measured as standard ellipse area (i.e. the isotopic niche), was consistently and significantly smaller compared to uninfected conspecifics. These niches of infected fishes always sat within that of uninfected fish, suggesting trophic specialisation in hosts. These results suggested trophic specialisation is a potentially important non-lethal consequence of parasite infection that results from impaired functional traits of the host

    Heavy Flavour measurements in Pb-Pb collisions with the upgraded ALICE Inner Tracking System

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    During the second LHC long shutdown (LS2) the Inner Tracking System (ITS) of ALICE (A Large Ion Collider Experiment) will be replaced by seven layers of CMOS Monolithic Active Pixel Sensors (MAPS). The latest innovations in silicon imaging technology allow for the construction of large, ultra-thin silicon wafers which can further improve the capabilities of the ALICE tracker. The research and development studies towards the construction of a novel vertex detector have started. The detector installation has been proposed for the third LHC long shutdown (LS3) during which the three innermost layers shall be replaced by three cylindrical layers of large curved CMOS wafers. This upgrade (ITS3) will further improve the impact parameter resolution and the tracking efficiency of low momentum particles. The innermost layer will be positioned closer to the interaction point and the material budget will be reduced down to 0.05%X0\%X_0 per layer. Monte Carlo simulations of a simplified ITS3 geometry within the ITS2 design indicate an improvement in the impact parameter resolution and the tracking efficiency, which are of crucial importance for measurements of heavy-flavour hadrons. This contribution shows the improved performance for the example of the Λb\Lambda_{\mathrm{b}}, for which the significance of its measurement is extracted based on these MC simulations. A significant improvement by almost a factor of three in the low momentum region compared to the ITS2 is observed

    Neo-Aristotelian Naturalism and the Evolutionary Objection: Rethinking the Relevance of Empirical Science

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    Neo-Aristotelian metaethical naturalism is a modern attempt at naturalizing ethics using ideas from Aristotle’s teleological metaphysics. Proponents of this view argue that moral virtue in human beings is an instance of natural goodness, a kind of goodness supposedly also found in the realm of non-human living things. Many critics question whether neo-Aristotelian naturalism is tenable in light of modern evolutionary biology. Two influential lines of objection have appealed to an evolutionary understanding of human nature and natural teleology to argue against this view. In this paper, I offer a reconstruction of these two seemingly different lines of objection as raising instances of the same dilemma, giving neo-Aristotelians a choice between contradicting our considered moral judgment and abandoning metaethical naturalism. I argue that resolving the dilemma requires showing a particular kind of continuity between the norms of moral virtue and norms that are necessary for understanding non-human living things. I also argue that in order to show such a continuity, neo-Aristotelians need to revise the relationship they adopt with empirical science and acknowledge that the latter is relevant to assessing their central commitments regarding living things. Finally, I argue that to move this debate forward, both neo-Aristotelians and their critics should pay attention to recent work on the concept of organism in evolutionary and developmental biology

    Deforestation-driven food-web collapse linked to emerging tropical infectious disease, Mycobacterium ulcerans.

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    Generalist microorganisms are the agents of many emerging infectious diseases (EIDs), but their natural life cycles are difficult to predict due to the multiplicity of potential hosts and environmental reservoirs. Among 250 known human EIDs, many have been traced to tropical rain forests and specifically freshwater aquatic systems, which act as an interface between microbe-rich sediments or substrates and terrestrial habitats. Along with the rapid urbanization of developing countries, population encroachment, deforestation, and land-use modifications are expected to increase the risk of EID outbreaks. We show that the freshwater food-web collapse driven by land-use change has a nonlinear effect on the abundance of preferential hosts of a generalist bacterial pathogen, Mycobacterium ulcerans. This leads to an increase of the pathogen within systems at certain levels of environmental disturbance. The complex link between aquatic, terrestrial, and EID processes highlights the potential importance of species community composition and structure and species life history traits in disease risk estimation and mapping. Mechanisms such as the one shown here are also central in predicting how human-induced environmental change, for example, deforestation and changes in land use, may drive emergence
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