2,706 research outputs found
Investigating the differential emission measure and energetics of microflares with combined SDO/AIA and RHESSI observations
An important question in solar physics is whether solar microflares, the
smallest currently observable flare events in X-rays, possess the same
energetic properties as large flares. Recent surveys have suggested that
microflares may be less efficient particle accelerators than large flares, and
hence contribute less nonthermal energy, which may have implications for
coronal heating mechanisms. We therefore explore the energetic properties of
microflares by combining Extreme Ultraviolet (EUV) and X-ray measurements.
We present forward-fitting differential emission measure (DEM) analysis of 10
microflares. The fitting is constrained by combining, for the first time, high
temperature RHESSI observations and flux data from SDO/AIA. Two fitting models
are tested for the DEM; a Gaussian distribution and a uniform DEM profile. A
Gaussian fit proved unable to explain the observations for any of the studied
microflares. However, 8 of 10 events studied were reasonably fit by a uniform
DEM profile. Hence microflare plasma can be considered to be significantly
multi-thermal, and may not be significantly peaked or contain resolvable fine
structure, within the uncertainties of the observational instruments.
The thermal and non-thermal energy is estimated for each microflare,
comparing the energy budget with an isothermal plasma assumption. From the
multithermal fits the minimum non-thermal energy content was found to average
approximately 30% of the estimated thermal energy. By comparison, under an
isothermal model the non-thermal and thermal energy estimates were generally
comparable. Hence, multi-thermal plasma is an important consideration for solar
microflares that substantially alters their thermal and non-thermal energy
content.Comment: 13 pages, 10 Figures, 2 tables. Accepted for publication in the
Astrophysical Journa
The Electron Scattering Region in Seyfert Nuclei
The electron scattering region (ESR) is one of important ingredients in
Seyfert nuclei because it makes possible to observe the hidden broad line
region (hereafter HBLR) in some type 2 Seyfert nuclei (hereafter S2s). However,
little is known about its physical and geometrical properties. Using the number
ratio of S2s with and without HBLR, we investigate statistically where the ESR
is in Seyfert nuclei. Our analysis suggests that the ESR is located at radius
between 0.01 pc and 0.1 pc from the central engine. We also
discuss a possible origin of the ESR briefly.Comment: 5 pages and 1 figure. The Astrophysical Journal (Letters), in pres
Disease management interventions for improving self-management in lower-limb peripheral arterial disease
The objective of this review is to systematically review, synthesise and quantify the effects of non-pharmacological and non-surgical chronic disease management interventions targeting self-management for people with lower-limb PAD
Meeting the challenges posed by an escalating diabetes healthcare burden: A mixed methods study
© 2019, © 2019 Informa UK Limited, trading as Taylor & Francis Group. Background: The ongoing escalation in the incidence of diabetes is contributing to a growing burden on health services because patients with diabetes as a co-morbidity are now spread throughout the hospital (rather than being located in specific areas). Thus, there is a need for expertise in diabetes care throughout services to ensure optimal care and reduce threats to patient safety. Aims and objectives: To identify new strategies to maintain optimal care for patients with diabetes while in hospital. Design: Mixed methods underpinned by Appreciative Inquiry. Methods: The Diabetes Knowledge Questionnaire Survey (DKQS) (n = 173); focus group interviews with nurses and midwives (n = 40), and individual interviews with recently discharged hospital patients (n = 6). Quantitative data were analysed using descriptive statistics and qualitative data by thematic analysis. Results: Highlight a need to enhance knowledge and confidence of diabetes management among nursing, midwifery, medical and ancillary staff through the introduction of focused education strategies. This, together with improved communication and team work, is required to relieve the burdens on frontline nursing staff and patients caused by delays in prescribing and reviewing insulin requirements and in accessing needed food for people with diabetes. Conclusions: In seeking solutions to the challenges in caring for hospitalised patients with diabetes there is a need to work across the entire hospital workforce and to develop effective and efficient methods for ensuring appropriate skills and knowledge of diabetes management for staff across complex and rapidly changing hospital systems. Relevance to clinical practice: The introduction and implementation of innovative educational and organisational strategies are needed to assist in meeting the challenges posed by an escalating diabetes healthcare burden. The safety of patients with diabetes can be optimised with the timely availability of appropriate meals and snacks, and enhanced coordination and communication between and within multidisciplinary teams
Effects of crack tip geometry on dislocation emission and cleavage: A possible path to enhanced ductility
We present a systematic study of the effect of crack blunting on subsequent
crack propagation and dislocation emission. We show that the stress intensity
factor required to propagate the crack is increased as the crack is blunted by
up to thirteen atomic layers, but only by a relatively modest amount for a
crack with a sharp 60 corner. The effect of the blunting is far less
than would be expected from a smoothly blunted crack; the sharp corners
preserve the stress concentration, reducing the effect of the blunting.
However, for some material parameters blunting changes the preferred
deformation mode from brittle cleavage to dislocation emission. In such
materials, the absorption of preexisting dislocations by the crack tip can
cause the crack tip to be locally arrested, causing a significant increase in
the microscopic toughness of the crack tip. Continuum plasticity models have
shown that even a moderate increase in the microscopic toughness can lead to an
increase in the macroscopic fracture toughness of the material by several
orders of magnitude. We thus propose an atomic-scale mechanism at the crack
tip, that ultimately may lead to a high fracture toughness in some materials
where a sharp crack would seem to be able to propagate in a brittle manner.
Results for blunt cracks loaded in mode II are also presented.Comment: 12 pages, REVTeX using epsfig.sty. 13 PostScript figures. Final
version to appear in Phys. Rev. B. Main changes: Discussion slightly
shortened, one figure remove
Spatially Resolved Far-Ultraviolet Spectroscopy of the Nuclear Region of NGC 1068
We carry out high-resolution FUSE spectroscopy of the nuclear region of NGC
1068. The first set of spectra was obtained with a 30" square aperture that
collects all emission from the narrow-line region. The data reveal a strong
broad OVI component of FWHM ~3500 kms-1 and two narrow OVI 1031/1037 components
of ~350 kms-1. The CIII 977 and NIII 991 emission lines in this spectrum can be
fitted with a narrow component of FWHM ~1000 kms-1 and a broad one of ~2500
kms-1. Another set of seven spatially resolved spectra were made using a long
slit of 1.25" X 20", at steps of ~1" along the axis of the emission-line cone.
We find that (1) Major emission lines in the FUSE wavelength range consist of a
broad and a narrow component; (2) There is a gradient in the velocity field for
the narrow OVI component of ~200 kms-1 from ~2" southwest of the nucleus to ~4"
northeast. A similar pattern is also observed with the broad OVI component,
with a gradient of ~3000 kms-1. These are consistent with the HST/STIS findings
and suggest a biconical structure in which the velocity field is mainly radial
outflow; (3) A major portion of the CIII and NIII line flux is produced in the
compact core. They are therefore not effective temperature diagnostics for the
conical region; and (4) The best-fitted UV continuum suggests virtually no
reddening, and the HeII 1085/1640 ratio suggests a consistently low extinction
factor across the cone.Comment: To appear in the Astrophysical Journal. 37 pages with 12 figure
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Self-Administered Computer Therapy for Apraxia of Speech
Background and Purpose
There is currently little evidence on effective interventions for poststroke apraxia of speech. We report outcomes of a trial of self-administered computer therapy for apraxia of speech.
Methods
Effects of speech intervention on naming and repetition of treated and untreated words were compared with those of a visuospatial sham program. The study used a parallel-group, 2-period, crossover design, with participants receiving 2 interventions. Fifty participants with chronic and stable apraxia of speech were randomly allocated to 1 of 2 order conditions: speech-first condition versus sham-first condition. Period 1 design was equivalent to a randomized controlled trial. We report results for this period and profile the effect of the period 2 crossover.
Results
Period 1 results revealed significant improvement in naming and repetition only in the speech-first group. The sham-first group displayed improvement in speech production after speech intervention in period 2. Significant improvement of treated words was found in both naming and repetition, with little generalization to structurally similar and dissimilar untreated words. Speech gains were largely maintained after withdrawal of intervention. There was a significant relationship between treatment dose and response. However, average self-administered dose was modest for both groups. Future software design would benefit from incorporation of social and gaming components to boost motivation.
Conclusions
Single-word production can be improved in chronic apraxia of speech with behavioral intervention. Self-administered computerized therapy is a promising method for delivering high-intensity speech/language rehabilitation
Detection of Trichomonas vaginalis Using the Polymerase Chain Reaction in Pregnant and Non-Pregnant Women
Objective: Trichomonas vaginalis vaginal infections are often both asymptomatic and difficult to
detect by current methods. We evaluated the ability of a newly developed polymerase chain reaction (PCR) assay to
identify T. vaginalis in vaginal samples from pregnant and non-pregnant women
Análise genética em populações de Butia eriospatha (Mart. ex Drude) Becc utilizando marcadores moleculares RAPD.
bitstream/CENARGEN/29611/1/cot170.pd
Investigating the ecology and evolution of cryptic marine nematode species through quantitative real-time PCR of the ribosomal ITS region
The presence of morphologically similar but genetically distinct species has impacted biogeographical and ecological paradigms. In marine sediments, free-living nematodes form one of the most abundant and diverse faunal groups. Inferring the importance of nematode diversity for ecosystem functioning requires species-level identification, which is hampered by the lack of easily observable diagnostic characters and the presence of cryptic species. New techniques are urgently needed to adequately study the ecology and evolution of cryptic species. The aim of the present study was to evaluate the potential of a quantitative real-time PCR (qPCR) assay using the internal transcribed spacer (ITS) region of the ribosomal DNA to detect and quantify cryptic species of the R. (P.) marina complex. All primer pairs proved to be highly specific, and each primer pair was able to detect a single juvenile in a pool of 100 nematodes. Ct values were significantly different between developmental stages for all species except for PmIII. Despite differences between developmental stages, a strong correlation was observed between the amount of extracted DNA and the number of nematodes present. Relative and absolute quantification estimates were comparable and resulted in strong positive correlations between the qPCR estimate and the actual number of nematodes present in the samples. The qPCR assay developed here provides the ability to quickly identify and quantify cryptic nematode species and will facilitate their study in laboratory and field settings
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