346 research outputs found
Relativistic Attosecond Electron Bunches from Laser-Illuminated Droplets
The generation of relativistic attosecond electron bunches is observed in
three-dimensional, relativistic particle-in-cell simulations of the interaction
of intense laser light with droplets. The electron bunches are emitted under
certain angles which depend on the ratios of droplet radius to wavelength and
plasma frequency to laser frequency. The mechanism behind the multi-MeV
attosecond electron bunch generation is investigated using Mie theory. It is
shown that the angular distribution and the high electron energies are due to a
parameter-sensitive, time-dependent local field enhancement at the droplet
surface.Comment: 4 pages, 5 figures, REVTeX-styl
Electron self-injection threshold for the tandem-pulse laser wakefield accelerator
A controllable injection scheme is key to producing high quality laser-driven
electron beams and X-rays. Self-injection is the most straightforward scheme
leading to high current and peak energies, but is susceptible to variations in
laser parameters and target characteristics. In this work improved control of
electron self-injection in the nonlinear cavity regime using two laser-pulses
propagating in tandem is investigated. In particular the advantages of the
tandem-pulse scheme in terms of injection threshold, electron energy and beam
properties in a regime relevant to betatron radiation are demonstrated.
Moreover it is shown that the laser power threshold for electron self-injection
can be reduced by up to a factor of two compared to the standard, single-pulse
wakefield scheme.Comment: 11 pages, 9 figures, submitted for publication (2019
A HACCP-based approach to mastitis control in dairy herds. Part 1: Development
Hazard Analysis and Critical Control Points (HACCP) systems are a risk based preventive approach developed to increase levels of food safety assurance. This is part 1 of a pilot study on the development, implementation and evaluation of a HACCP-based approach for the control of good udder health in dairy cows. The paper describes the use of a novel approach based on a deconstruction of the infectious process in mastitis to identify Critical Control Points (CCPs) and develop a HACCP-based system to prevent and control mastitis in dairy herds. The approach involved the creation of an Infectious Process Flow Diagram, which was then cross-referenced to two production process flow diagrams of the milking process and cow management cycle. The HACCP plan developed, may be suitable for customisation and implementation on dairy farms. This is a logical, systematic approach to the development of a mastitis control programme that could be used as a template for the development of control programmes for other infectious diseases in the dairy herd
Core Health Outcomes In Childhood Epilepsy (CHOICE):Protocol for the selection of a core outcome set
This is the final version of the article. Available from BioMed Central via the DOI in this record.BACKGROUND: There is increasing recognition that establishing a core set of outcomes to be evaluated and reported in trials of interventions for particular conditions will improve the usefulness of health research. There is no established core outcome set for childhood epilepsy. The aim of this work is to select a core outcome set to be used in evaluative research of interventions for children with rolandic epilepsy, as an exemplar of common childhood epilepsy syndromes. METHODS: First we will identify what outcomes should be measured; then we will decide how to measure those outcomes. We will engage relevant UK charities and health professional societies as partners, and convene advisory panels for young people with epilepsy and parents of children with epilepsy. We will identify candidate outcomes from a search for trials of interventions for childhood epilepsy, statutory guidance and consultation with our advisory panels. Families, charities and health, education and neuropsychology professionals will be invited to participate in a Delphi survey following recommended practices in the development of core outcome sets. Participants will be able to recommend additional outcome domains. Over three rounds of Delphi survey participants will rate the importance of candidate outcome domains and state the rationale for their decisions. Over the three rounds we will seek consensus across and between families and health professionals on the more important outcomes. A face-to-face meeting will be convened to ratify the core outcome set. We will then review and recommend ways to measure the shortlisted outcomes using clinical assessment and/or patient-reported outcome measures. DISCUSSION: Our methodology is a proportionate and pragmatic approach to expediently produce a core outcome set for evaluative research of interventions aiming to improve the health of children with epilepsy. A number of decisions have to be made when designing a study to develop a core outcome set including defining the scope, choosing which stakeholders to engage, most effective ways to elicit their views, especially children and a potential role for qualitative research.This study is part of Changing Agendas on Sleep, Treatment and Learning in Childhood Epilepsy (CASTLE), which is funded by the National Institute for Health Research (NIHR) Programme Grants for Applied Research RP-PG-0615-20007
Outcomes of ventriculoperitoneal shunt insertion in the management of idiopathic intracranial hypertension in children
Purpose The ventriculoperitoneal (VP) shunt has become the
procedure of choice for treatment of idiopathic intracranial
hypertension (IIH). We aimed to assess the efficacy of
frameless stereotactic placement of VP shunts for the management of medically resistant IIH in children and to assess the role of gender and obesity in the aetiology of the condition.
Methods This is a retrospective analysis of the case notes of 10 patients treated surgically at the University Hospital of
Wales in Cardiff, from May 2006 to September 2012.
Results VP shunts were successful in relieving headache,
papilloedema and stabilising vision. No sex predilection was
identified, and increased BMI was a feature throughout the
population, regardless of age.
Conclusions Neuronavigated VP shunt insertion is an effective mode of treatment for medically resistant IIH in children. The aetiological picture in children does not seem to be dominated by obesity, as in adults. Literature on childhood IIH is sparse, and larger scale, comparative studies would be of benefit to treating clinicians
Nurses\u27 Alumnae Association Bulletin - Volume 16 Number 1
Alumnae Notes
ANA Biennial Convention
Cancer of the Cervix, Uterus and Ovaries
Committee Reports
Digest of Alumnae Association Meetings
Greetings from Miss Childs
Greetings from the President
Graduation Awards - 1950
Isotopes and the Nurse - Dr. T.P. Eberhard
Marriages
Necrology
New Arrivals
Nursing Care in Heart Disease with Pulmonary Infarction
Nursing Care of a Mitral Commissurotomy
Physical Advances at Jefferson - 1950
Policies of the Private Duty Nurses\u27 Registry
Staff Activities, 1950-1951
Students\u27 Corner
The Department of Surgical Research - Drs. Templeton and Gibbon
White Haven and Barton Memorial Division
Time perception and its neuropsychological correlates in patients with schizophrenia and in healthy volunteers
Disordered time perception has been reported in schizophrenia. We investigated time perception dysfunction and its neuropsychological correlates in patients with schizophrenia. Participants comprised 38 patients and 38 age- and sex-matched healthy volunteers who were compared in an auditory temporal bisection paradigm using two interval ranges (a 400/800 ins condition and a 1000/2000 ms condition). In the temporal bisection, subjects were required to categorise a probe duration as short or long, based upon the similarity with two reference durations. All subjects also completed a battery of neuropsychological tests measuring sustained attention, short- and long-term memory and executive function. In the 400/800 ins condition, patients judged durations significantly shorter than did control subjects. Patients also exhibited decreased temporal sensitivity in both conditions. We found in both groups a negative association between temporal sensitivity and sustained attention for the 400/800 ms condition, and between temporal sensitivity and long-term memory for the 1000/200 ms condition. In patients, short-term memory performance was negatively associated with duration judgement in both conditions, while executive dysfunction was correlated to a general performance deficit in the 400/800 ms condition. These findings suggest the possibility that time perception abnormalities in schizophrenia are part of neuropsychological dysfunction and are likely to adversely impact upon activity of daily living. (c) 2008 Elsevier Ireland Ltd. All rights reserved
Role of surface roughness in hard x-ray emission from femtosecond laser produced copper plasmas
The hard x-ray emission in the energy range of 30-300 keV from copper plasmas
produced by 100 fs, 806 nm laser pulses at intensities in the range of
10 W cm is investigated. We demonstrate that surface
roughness of the targets overrides the role of polarization state in the
coupling of light to the plasma. We further show that surface roughness has a
significant role in enhancing the x-ray emission in the above mentioned energy
range.Comment: 5 pages, 4 figures, to appear in Phys. Rev.
Generation of ultra-short light pulses by a rapidly ionizing thin foil
A thin and dense plasma layer is created when a sufficiently strong laser
pulse impinges on a solid target. The nonlinearity introduced by the
time-dependent electron density leads to the generation of harmonics. The pulse
duration of the harmonic radiation is related to the risetime of the electron
density and thus can be affected by the shape of the incident pulse and its
peak field strength. Results are presented from numerical
particle-in-cell-simulations of an intense laser pulse interacting with a thin
foil target. An analytical model which shows how the harmonics are created is
introduced. The proposed scheme might be a promising way towards the generation
of attosecond pulses.
PACS number(s): 52.40.Nk, 52.50.Jm, 52.65.RrComment: Second Revised Version, 13 pages (REVTeX), 3 figures in ps-format,
submitted for publication to Physical Review E, WWW:
http://www.physik.tu-darmstadt.de/tqe
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