5,008 research outputs found
An analytical approach to sorting in periodic potentials
There has been a recent revolution in the ability to manipulate
micrometer-sized objects on surfaces patterned by traps or obstacles of
controllable configurations and shapes. One application of this technology is
to separate particles driven across such a surface by an external force
according to some particle characteristic such as size or index of refraction.
The surface features cause the trajectories of particles driven across the
surface to deviate from the direction of the force by an amount that depends on
the particular characteristic, thus leading to sorting. While models of this
behavior have provided a good understanding of these observations, the
solutions have so far been primarily numerical. In this paper we provide
analytic predictions for the dependence of the angle between the direction of
motion and the external force on a number of model parameters for periodic as
well as random surfaces. We test these predictions against exact numerical
simulations
Development Of Technical Education In Dublin : Technical Education Report Pamphlet
Lecture delivered by Martin M. Gleeson, Chief Executive Officer, City of Dublin Vocational Education Committe, at the summer meeting of the Asssociation of Technical Institutions, 28th -30th June, 1956
Introduction to a Special Issue on the Impact of Immigrant Legalization Initiatives: International Perspectives on Immigration and the World of Work
This article is the third in a series to celebrate the 70th anniversary of the ILR Review. The series features articles that analyze the state of research and future directions for important themes the journal has featured over its many years of publication. In this issue, we also feature a special cluster of articles and book reviews on one of the most critical labor market issues across the globe—the legalization and integration of immigrants into national labor markets.
Despite the urgent need for immigration reform in the United States, there is a paucity of US research that looks at the impact of a shift from unauthorized to legal immigrant status in the workplace. The US immigration literature has also paid little attention to immigrant legalization policies outside of the United States, despite the fact that other countries have implemented such policies with far more regularity. The articles in this special issue draw on studies of legalization initiatives in major immigrant destinations: Canada, Italy, and the United Kingdom. Together they underscore the importance of cross-national perspectives for understanding the range of legalization programs and their impact on immigrant workers, the workplace, and the labor market. These findings contribute to key questions in migration scholarship and inform the global policy debate surrounding the integration and well-being of immigrant
Control of Ship capsize in stern quartering seas.
A non-linear mathematical model for the roll-yaw behaviour of a ship is used to predict capsize of a small
tanker which sank in the North Sea some years ago. This capsize problem was initially simulated on an analogue
computer by the Danish Maritime Authorities as well as being tank tested. The problem was simulated using the
digital package SIMULINK, which produced comparable results indicating instability in waves of just less than 3 m
in height. Validation of the results is attempted and a discussion of possible improvements to the model is given.
Simulated responses of the tanker with simple hydrodynamic fin stabilisers show that capsize could have been
prevented by this means in waves up to 7 m in height. Active PID control using a simple full span elevon is used to show a factor of ten reduction in roll angle to much greater waves. This work is of use to ship designers illustrating that stability can be enhanced for a fraction of the cost of major redesign of the ship hull and can be tailored to load conditions
Knee joint neuromuscular activation performance during muscle damage and superimposed fatigue
This study examined the concurrent effects of exercise-induced muscle damage and superimposed acute fatigue on the neuromuscular activation performance of the knee flexors of nine males (age: 26.7 ± 6.1yrs; height 1.81 ± 0.05m; body mass 81.2 ± 11.7kg [mean ± SD]). Measures were obtained during three experimental conditions: (i) FAT-EEVID, involving acute fatiguing exercise performed on each assessment occasion plus a single episode of eccentric exercise performed on the first occasion and after the fatigue trial; (ii) FAT, involving the fatiguing exercise only and; (iii) CON consisting of no exercise. Assessments were performed prior to (pre) and at lh, 24h, 48h, 72h, and 168h relative to the eccentric exercise. Repeated-measures ANOVAs showed that muscle damage within the FAT-EEVID condition elicited reductions of up to 38%, 24%) and 65%> in volitional peak force, electromechanical delay and rate of force development compared to baseline and controls, respectively (F[io, 80] = 2.3 to 4.6; p to 30.7%>) following acute fatigue (Fp; i6] = 4.3 to 9.1; p ; Fp, iq = 3.9; p <0.05). The safeguarding of evoked muscle activation capability despite compromised volitional performance might reveal aspects of capabilities for emergency and protective responses during episodes of fatigue and antecedent muscle damaging exercise
Becoming effective communicators with children: developing practitioner capability through social work education
Social workers employed within statutory settings in countries such as the UK are subject to legal and policy requirements to communicate directly and effectively with children and young people. Qualifying social work education is expected to prepare students so that they can practice competently. However, in England at least, practice and education are both falling short. While active attention is now being given to ways of facilitating improvements in practice, almost nothing is known about how qualifying courses might best promote student learning. This paper reports some of the findings from a UK-based empirical study into factors and processes which support students in developing the self-efficacy and ‘applied understanding’ they need to undertake effective direct work with children. A superficial focus on the ‘doing’ of communication (techniques and skills) appears to be inadequate: courses must additionally provide a range of experiential, participatory, didactic and critically reflective learning opportunities which can enable deep learning of the underpinning knowledges, ethical commitments and personal qualities also needed. A model is presented of an integrated and coherent learning sequence which could be used by programmes to ensure students develop the necessary generic, child-centred and ‘applied child-specialist’ capabilities in communication with children
Estimating the economic burden of cardiovascular events in patients receiving lipid-modifying therapy in the UK.
OBJECTIVES: To characterise the costs to the UK National Health Service of cardiovascular (CV) events among individuals receiving lipid-modifying therapy. DESIGN: Retrospective cohort study using Clinical Practice Research Datalink records from 2006 to 2012 to identify individuals with their first and second CV-related hospitalisations (first event and second event cohorts). Within-person differences were used to estimate CV-related outcomes. SETTING: Patients in the UK who had their first CV event between January 2006 and March 2012. PARTICIPANTS: Patients ≥18 years who had a CV event and received at least 2 lipid-modifying therapy prescriptions within 180 days beforehand. PRIMARY AND SECONDARY OUTCOME MEASURES: Direct medical costs (2014 £) were estimated in 3 periods: baseline (pre-event), acute (6 months afterwards) and long-term (subsequent 30 months). Primary outcomes included incremental costs, resource usage and total costs per period. RESULTS: There were 24 093 patients in the first event cohort of whom 5274 were included in the second event cohort. The mean incremental acute CV event costs for the first event and second event cohorts were: coronary artery bypass graft/percutaneous transluminal coronary angioplasty (CABG/PTCA) £5635 and £5823, myocardial infarction £4275 and £4301, ischaemic stroke £3512 and £4572, heart failure £2444 and £3461, unstable angina £2179 and £2489 and transient ischaemic attack £1537 and £1814. The mean incremental long-term costs were: heart failure £848 and £2829, myocardial infarction £922 and £1385, ischaemic stroke £973 and £682, transient ischaemic attack £705 and £1692, unstable angina £328 and £677, and CABG/PTCA £-368 and £599. Hospitalisation accounted for 95% of acute and 61% of long-term incremental costs. Higher comorbidity was associated with higher long-term costs. CONCLUSIONS: Revascularisation and myocardial infarction were associated with the highest incremental costs following a CV event. On the basis of real-world data, the economic burden of CV events in the UK is substantial, particularly among those with greater comorbidity burden
Anomalous increase in nematic-isotropic transition temperature in dimer molecules induced by magnetic field
We have determined the nematic-isotropic transition temperature as a function of applied magnetic field in three different thermotropic liquid crystalline dimers. These molecules are comprised of two rigid calamitic moieties joined end to end by flexible spacers with odd numbers of methylene groups. They show an unprecedented magnetic field enhancement of nematic order in that the transition temperature is increased by up to 15K when subjected to 22T magnetic field. The increase is conjectured to be caused by a magnetic field-induced decrease of the average bend angle in the aliphatic spacers connecting the rigid mesogenic units of the dimers
The engagement of young people in drug interventions in coercive contexts: findings from a cross-national European study
Background: The engagement of young people has been a neglected area in youth justice and drugs policy and practice. This paper explores the concept of ‘engagement’ in relation to drugs interventions in custodial and community settings in different European countries.
Methods: Interviews were undertaken with young people (aged 14-25 years) in contact with the criminal justice system who use illegal drugs and with practitioners involved in the delivery of interventions for our target group in Denmark, Italy, Poland the UK.
Results: The key techniques to engage young people were described in similar terms across the countries. These included forming relationships based on trust, honesty and empathy, setting goals collaboratively and employing practitioners with lived experience and understanding. The objectives and activities on offer are often constrained by the criminal justice contexts.
Conclusions: Despite the differences between the countries in terms of criminal justice systems and the structure of drug interventions, there were remarkable similarities in the ways young people and practitioners described effective engagement. Strong emphasis on operational engagement to ensure positive relationships between young people and practitioners was important in the design and delivery of interventions. Practitioners working in criminal justice contexts need to have flexibility and autonomy to work creatively to find ways to engage, connect and inspire young people
Non-local spatial frequency response of photopolymer materials containing chain transfer agents: I. Theoretical modelling
The non-local photopolymerization driven diffusion (NPDD) model predicts that a reduction in
the non-local response length within a photopolymer material will improve its high spatial
frequency response. The introduction of a chain transfer agent reduces the average molecular
weight of polymer chains formed during free radical polymerization. Therefore a chain transfer
agent (CTA) provides a practical method to reduce the non-local response length. An extended
NPDD model is presented, which includes the chain transfer reaction and most major
photochemical processes. The addition of a chain transfer agent into an acrylamide/polyvinyl
alcohol photopolymer material is simulated and the predictions of the model are examined. The
predictions of the model are experimentally examined in part II of this paper
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