3,256 research outputs found
The upgrade of the ALICE Inner Tracking System
The Inner Tracking System (ITS) of the ALICE experiment will be upgraded
during the second long LHC shutdown in . 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
collisions to 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 m. The use of MAPS together
with a stringent mechanical design allows for the reduction of the material
budget down to 0.35% for the innermost layers and 1% 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
Heavy Flavour measurements in PbPb collisions with the upgraded ALICE Inner Tracking System
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 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 , 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
Understanding the threats posed by non-native species: public vs. conservation managers.
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
Forecasting Exchange-Rates via Local Approximation Methods and Neural Networks
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
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
Sensitivity to the temporal structure of rapid sound sequences — An MEG study
AbstractTo probe sensitivity to the time structure of ongoing sound sequences, we measured MEG responses, in human listeners, to the offset of long tone-pip sequences containing various forms of temporal regularity. If listeners learn sequence temporal properties and form expectancies about the arrival time of an upcoming tone, sequence offset should be detectable as soon as an expected tone fails to arrive. Therefore, latencies of offset responses are indicative of the extent to which the temporal pattern has been acquired. In Exp1, sequences were isochronous with tone inter-onset-interval (IOI) set to 75, 125 or 225ms. Exp2 comprised of non-isochronous, temporally regular sequences, comprised of the IOIs above. Exp3 used the same sequences as Exp2 but listeners were required to monitor them for occasional frequency deviants. Analysis of the latency of offset responses revealed that the temporal structure of (even rather simple) regular sequences is not learnt precisely when the sequences are ignored. Pattern coding, supported by a network of temporal, parietal and frontal sources, improved considerably when the signals were made behaviourally pertinent. Thus, contrary to what might be expected in the context of an ‘early warning system’ framework, learning of temporal structure is not automatic, but affected by the signal's behavioural relevance
Isolated cotton-wool spots of unknown etiology: management and sequential spectral domain optical coherence tomography documentation
Cotton-wool spots (CWSs) are common retinal manifestations of many diseases including diabetes mellitus, systemic hypertension, and acquired immunodeficiency syndrome. Clinically they appear as whitish, fluffy patches on the retina and eventually fade with time. In this study, spectral domain optical coherence tomography (SD-OCT) with mapping was used to demonstrate in vivo the characteristics of an isolated CWS in a 59-year-old patient as well as its appearance immediately after ophthalmoscopic resolution. Presented here is the work-up and management of this clinical problem for the ophthalmologist. The authors propose that SD-OCT could be a valuable research tool in characterizing and following the dynamic CWS changes at individual retinal layer level, with potential clinical applications as a screening or diagnostic tool in CWS-related diseases
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The changing landscape of OSH regulation in the UK
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
The Impact of Pain Assessment on Critically Ill Patients’ Outcomes: A Systematic Review
In critically ill patients, pain is a major problem. Efficient pain management depends on a systematic, comprehensive assessment of pain. We aimed to review and synthesize current evidence on the impact of a systematic approach to pain assessment on critically ill patients’ outcomes. A systematic review of published studies (CINAHL, PUBMED, SCOPUS, EMBASE, and COCHRANE databases) with predetermined eligibility criteria was undertaken. Methodological quality was assessed by the EPHPP quality assessment tool. A total of 10 eligible studies were identified. Due to big heterogeneity, quantitative synthesis was not feasible. Most studies indicated the frequency, duration of pain assessment, and types of pain assessment tools. Methodological quality assessment yielded “strong” ratings for 5/10 and “weak” ratings for 3/10 studies. Implementation of systematic approaches to pain assessment appears to associate with more frequent documented reports of pain and more efficient decisions for pain management. There was evidence of favorable effects on pain intensity, duration of mechanical ventilation, length of ICU stay, mortality, adverse events, and complications. This systematic review demonstrates a link between systematic pain assessment and outcome in critical illness. However, the current level of evidence is insufficient to draw firm conclusions. More high quality randomized clinical studies are needed
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