592 research outputs found
Soliton solutions for quasilinear Schrodinger equations, I
No full textFor a class of quasilinear Schrodinger equations we establish the existence of ground states of soliton type solutions by a minimization argument.Mathematics, AppliedMathematicsSCI(E)95ARTICLE2441-44813
THE CALCULATIONS OF LOW-ENERGY BEAM TRANSPORT
No full textAfter the ion beams are extracted from ion sources, it is necessary to transport the beams to the experimental areas or to the accelerating installations. Low-energy beam transport systems usually consist of some axially symmetrical electrostatic focusing and accelerating lenses as well as quadrupoles and dipoles. Here, we discuss the calculation methods for the beam transport in electrostatic lens systems and describe a computer program for this use.Instruments & InstrumentationPhysics, AppliedSCI(E)
Physical–chemical characterisation of the particulate matter inside two road tunnels in the São Paulo Metropolitan Area
No full textabstract: The notable increase in biofuel usage by the road transportation sector in Brazil during recent years has significantly altered the vehicular fuel composition. Consequently, many uncertainties are currently found in particulate matter vehicular emission profiles. In an effort to better characterise the emitted particulate matter, measurements of aerosol physical and chemical properties were undertaken inside two tunnels located in the São Paulo Metropolitan Area (SPMA). The tunnels show very distinct fleet profiles: in the Jânio Quadros (JQ) tunnel, the vast majority of the circulating fleet are light duty vehicles (LDVs), fuelled on average with the same amount of ethanol as gasoline. In the Rodoanel (RA) tunnel, the particulate emission is dominated by heavy duty vehicles (HDVs) fuelled with diesel (5% biodiesel). In the JQ tunnel, PM[subscript 2.5] concentration was on average 52 μg m[superscript −3], with the largest contribution of organic mass (OM, 42%), followed by elemental carbon (EC, 17%) and crustal elements (13%). Sulphate accounted for 7% of PM[subscript 2.5] and the sum of other trace elements was 10%. In the RA tunnel, PM[subscript 2.5] was on average 233 μg m[superscript −3], mostly composed of EC (52%) and OM (39%). Sulphate, crustal and the trace elements showed a minor contribution with 5%, 1%, and 1%, respectively. The average OC : EC ratio in the JQ tunnel was 1.59 ± 0.09, indicating an important contribution of EC despite the high ethanol fraction in the fuel composition. In the RA tunnel, the OC : EC ratio was 0.49 ± 0.12, consistent with previous measurements of diesel-fuelled HDVs. Besides bulk carbonaceous aerosol measurement, polycyclic aromatic hydrocarbons (PAHs) were quantified. The sum of the PAHs concentration was 56 ± 5 ng m[superscript −3] and 45 ± 9 ng m[superscript −3] in the RA and JQ tunnel, respectively. In the JQ tunnel, benzo(a)pyrene (BaP) ranged from 0.9 to 6.7 ng m[superscript −3] (0.02–0.1‰ of PM[subscript 2.5)] whereas in the RA tunnel BaP ranged from 0.9 to 4.9 ng m[superscript −3] (0.004–0. 02‰ of PM[subscript 2.5]), indicating an important relative contribution of LDVs emission to atmospheric BaP.This article and any associated published material is distributed under the Creative Commons Attribution 3.0 License. View the article as published at: http://www.atmos-chem-phys.net/13/12199/2013
A new approach to probing primordial non-Gaussianity
No full text08/02/13 meb Publisher version attached, OK to pub
Fracture energy of columnar freshwater ice: Influence of loading type, loading rate and size
No full textFunding Information: This work was funded though the Finland Distinguished Professor programme ”Scaling of Ice Strength: Measurements and Modeling”, and through the ARAJ research project, both funded by Business Finland and the industrial partners Aker Arctic Technology, Arctech Helsinki Shipyard, Arctia Shipping, ABB Marine, Finnish Transport Agency, Suomen Hyȵtytuuli Oy, and Ponvia Oy. This financial support is gratefully acknowledged. The second author (J.P.D.) thanks Business Finland for support by the FiDiPro Professorship from Aalto University, and the sabbatical support from Aalto University, which collectively supported an annual visit 2015–2016, and summer visits 2017–2019. Publisher Copyright: © 2021 The Author(s)This work investigates the influence of loading type, loading rate, and test size on the fracture energy of columnar freshwater S2 ice. The ice sheet in the Ice tank at Aalto University was very warm (above -0.5 ∘C) and thick (0.34<h<0.41 m). A program of nineteen mode I fracture tests using deeply cracked edge-cracked rectangular plates of various sizes (size range 1:39), loading types, and loading rates were carried out. Fourteen displacement-controlled tests (DC) were loaded monotonically to fracture, and five load-controlled tests (LC) were conducted with creep/cyclic-recovery and monotonic loading to fracture. Different methods for computing the fracture energy were applied and compared. The apparent fracture energy at crack growth initiation was obtained via Rice's J-integral expression (JQ) modified to be applicable to the special case of a deeply cracked edge-cracked plate as well as via a viscoelastic fictitious crack analysis (GVFCM). The work-of-fracture (Wf) was also evaluated. Both JQ and Wf were measured from the load-displacement record at the crack mouth. GVFCM was obtained from the back-calculated stress-separation (σ−δ) relation within the fracture process zone. A rather good agreement was obtained between GVFCM and JQ, especially for the large specimens. JQ and Wf exhibited interrelated size and rate effects. The Wf/JQ values for the DC tests were affected by rate and confined to a narrow range of 1 to 3. The creep-recovery loading did not affect the JQ values but led to an increase in the Wf and Wf/JQ values for most of the LC tests.Peer reviewe
What is the impact of contraceptive methods and mixes of contraceptive methods on contraceptive prevalence, unmet need for family planning, and unwanted and unintended pregnancies?
No full textBackground - In many low-and middle-income countries, there is high maternal, infant and child mortality due in part to low contraceptive use and high unmet need for family planning. The aim of this overview of systematic reviews is to synthesise the findings of systematic reviews conducted in this area to assess the impact of various contraceptive methods and mixes of contraceptive methods on contraceptive prevalence, unwanted and unintended pregnancies, and unmet need (a desire to limit the number of children but not currently using any contraception) for family planning in developing countries/regions.Methods - Eight databases (Bioline international, The Cochrane Library, Latin American and Caribbean Health Sciences Literature - LILACS, Popline, PubMed, Turning Research Into Practice, World Health Organisation Reproductive Health Library and Zetoc) were searched from 28 October 2010 to 08 December 2010. Cochrane and non-Cochrane systematic reviews were included. Eligible reviews included studies whose participants were sexually active women or men from countries classified as ‘developing’, ‘low-income’ or ‘middle-income’. Systematic reviews of any intervention (or combination of interventions) designed to increase contraceptive prevalence, reduce fertility or both were eligible. Data were extracted and synthesised narratively. A Measurement Tool to Assess Systematic Reviews, AMSTAR, was used to evaluate the quality of the included systematic reviews, and Grading of Recommendations, Assessment, Development and Evaluation (GRADE) was used to evaluate the quality of the body of evidence for each comparison. To aid the interpretation of the findings for a variety of settings, relevant contextual information was presented where possible.Results - There were 22 systematic reviews included in this overview of reviews. The overview examined a range of contraceptive methods, including modern (terminal and spacing) and traditional methods (such as withdrawal and periodic abstinence which do not require contraceptive substances or devices and also do not require clinical procedures). However, the systematic reviews included did not address all the objectives of the overview.The results of the review are summarised below according to the objectives.Objective 1: To assess the impact of various contraceptive methods and mixes ofcontraceptive methods on contraceptive prevalence in developing countries/regions. There was no systematic review that met this objective.Objective 2: To assess the impact of various contraceptive methods and mixes ofcontraceptive methods on unwanted and unintended pregnancies in developingcountries/regions.The body of evidence for the relative efficacy or effectiveness of a variety ofcontraceptive methods to prevent pregnancy in developing countries was generally rated as of low or moderate quality. There was, however, a number of comparisons (between different derivatives of the same contraceptive methods) for which the evidence was rated as of high or moderate quality. Evidence from systematic reviews is lacking on the acceptability of contraceptive methods and their impact on prevalence and on unmet needs for family planning. The evidence for the relative effectiveness of a variety of contraceptive methods to prevent pregnancy in developing countries is generally of low quality. There is some high-quality evidence comparing different derivatives of the same contraceptive methods, although this is more often evidence of efficacy than evidence of effectiveness.Objective 3: To assess the impact of various contraceptive methods and mixes ofcontraceptive methods on unmet need for family planning in developing countries/regions.There was no systematic review that met this objective
Small fish swimming in the shape of a shark: why politicians join political parties in the Pacific islands
No full textPolitical parties are ubiquitous features of contemporary models of representative democracy and are widely believed to be integral to transition, and yet persistently democratic Pacific Island countries tend to have ‘weakly’ institutionalised parties – some have none at all – that have little influence on the mobilisation of voters during elections. Party theory largely assumes that politicians form parties to win elections: the author asks why, given the commonly cited irrelevance of party politics in much of the Pacific, politicians join political parties at all. Drawing on 96 biographical accounts – including 72 in-depth interviews –he interprets the explanations politicians give for joining, leaving and changing parties. The author identifies three narratives. The first accords with an augmented rational actor model, the second with a responsible parties model and the third points to intrinsic motivations that are largely overlooked in the existing literature. The author concludes that a comprehensive account must include all three interpretations
Toxicity and in vitro activity of HIV-1 latency-reversing agents in primary CNS cells
No full textDespite the success of combination antiretroviral therapy (cART), HIV persists in long lived latently infected cells in the blood and tissue, and treatment is required lifelong. Recent clinical studies have trialed latency-reversing agents (LRA) as a method to eliminate latently infected cells; however, the effects of LRA on the central nervous system (CNS), a well-known site of virus persistence on cART, are unknown. In this study, we evaluated the toxicity and potency of a panel of commonly used and well-known LRA (panobinostat, romidepsin, vorinostat, chaetocin, disulfiram, hexamethylene bisacetamide [HMBA], and JQ-1) in primary fetal astrocytes (PFA) as well as monocyte-derived macrophages as a cellular model for brain perivascular macrophages. We show that most LRA are non-toxic in these cells at therapeutic concentrations. Additionally, romidepsin, JQ-1, and panobinostat were the most potent at inducing viral transcription, with greater magnitude observed in PFA. In contrast, vorinostat, chaetocin, disulfiram, and HMBA all demonstrated little or no induction of viral transcription. Together, these data suggest that some LRA could potentially activate transcription in latently infected cells in the CNS. We recommend that future trials of LRA also examine the effects of these agents on the CNS via examination of cerebrospinal fluid.Lachlan R. Gray, Hung On, Emma Roberts, Hao K. Lu, Michael A. Moso, Jacqueline A. Raison, Catherine Papaioannou, Wan-Jung Cheng, Anne M. Ellett, Jonathan C. Jacobson, Damian F.J. Purcell, Steve L. Wesselingh, Paul R. Gorry, Sharon R. Lewin, Melissa J. Churchil
A real-time information gathering agent based on ontology
No full textThis paper provides an agent based on an ontology that helps user to gather the real-time information. We present an approach of ontology representation based on concept graph and introduce the building and revising algorithms of knowledge base, then discuss the application of the ontology in information source representation. Experimental results show that the agent helps user accomplish the task effectively.Computer Science, Information SystemsComputer Science, Theory & MethodsSCI(E)CPCI-S(ISTP)
On optimality of jury selection in crowdsourcing
No full textRecent advances in crowdsourcing technologies enable computationally challenging tasks (e.g., sentiment analysis and entity resolution) to be performed by Internet workers, driven mainly by monetary incentives. A fundamental question is: how should workers be selected, so that the tasks in hand can be accomplished successfully and economically? In this paper, we study the Jury Selection Problem (JSP): Given a monetary budget, and a set of decision-making tasks (e.g., “Is Bill Gates still the CEO of Microsoft now?”), return the set of workers (called jury), such that their answers yield the highest “Jury Quality” (or JQ). Existing JSP solutions make use of the Majority Voting (MV) strategy, which uses the answer chosen by the largest number of workers. We show that MV does not yield the best solution for JSP. We further prove that among all voting strategies (including deterministic and randomized strategies), Bayesian Voting (BV) can optimally solve JSP. We then examine how to solve JSP based on BV. This is technically challenging, since computing the JQ with BV is NP-hard. We solve this problem by proposing an approximate algorithm that is computationally efficient. Our approximate JQ computation algorithm is also highly accurate, and its error is proved to be bounded within 1%. We extend our solution by considering the task owner’s “belief” (or prior) on the answers of the tasks. Experiments on synthetic and real datasets show that our new approach is consistently better than the best JSP solution known.published_or_final_versio
- …
