2,206 research outputs found
Phase Transition Study of Superconducting Microstructures
The presented results are part of a feasibility study of superheated
superconducting microstructure detectors. The microstructures (dots) were
fabricated using thin film patterning techniques with diameters ranging from
m up to m and thickness of m. We used arrays and single
dots to study the dynamics of the superheating and supercooling phase
transitions in a magnetic field parallel to the dot surface. The phase transi-
tions were produced by either varying the applied magnetic field strength at a
constant temperature or changing the bath temperature at a constant field.
Preliminary results on the dynamics of the phase transitions of arrays and
single indium dots will be reported.Comment: 7pages in LaTex format, five figures available upon request by
[email protected], preprint Bu-He 93/
Optimizing end-labeled free-solution electrophoresis by increasing the hydrodynamic friction of the drag-tag
We study the electrophoretic separation of polyelectrolytes of varying
lengths by means of end-labeled free-solution electrophoresis (ELFSE). A
coarse-grained molecular dynamics simulation model, using full electrostatic
interactions and a mesoscopic Lattice Boltzmann fluid to account for
hydrodynamic interactions, is used to characterize the drag coefficients of
different label types: linear and branched polymeric labels, as well as
transiently bound micelles.
It is specifically shown that the label's drag coefficient is determined by
its hydrodynamic size, and that the drag per label monomer is largest for
linear labels. However, the addition of side chains to a linear label offers
the possibility to increase the hydrodynamic size, and therefore the label
efficiency, without having to increase the linear length of the label, thereby
simplifying synthesis. The third class of labels investigated, transiently
bound micelles, seems very promising for the usage in ELFSE, as they provide a
significant higher hydrodynamic drag than the other label types.
The results are compared to theoretical predictions, and we investigate how
the efficiency of the ELFSE method can be improved by using smartly designed
drag-tags.Comment: 32 pages, 11 figures, submitted to Macromolecule
End-of-Life Delirium: Issues Regarding Recognition, Optimal Management and the Role of Sedation in the Dying Phase.
CONTEXT:
In end-of-life care, delirium is often not recognized and poses unique management challenges, especially in the case of refractory delirium in the terminal phase. OBJECTIVES:
To review: delirium in the terminal phase context, specifically in relation to recognition issues; the decision-making processes and management strategies regarding its reversibility; the potential refractoriness of delirium to symptomatic treatment; and the role of sedation in refractory delirium. METHODS:
We combined multidisciplinary input from delirium researchers and knowledge users at an international delirium study planning meeting and relevant electronic database literature searches (Ovid Medline, Embase, PsycINFO and CINAHL) to inform this narrative review. RESULTS:
The overall management strategy for delirium at the end of life is directed by the patient\u27s prognosis in association with the patient\u27s goals of care. As symptoms of delirium are often refractory in the terminal phase, especially in the case of agitated delirium, the judicious use of palliative sedation is frequently required. However, there remains a lack of high level evidence for the management of delirium in the terminal phase, including the role of antipsychotics and optimal sedation strategies. For the family and health care staff, clear communication, education and emotional support are vital components to assist with decision making and direct the treatment care plan. CONCLUSION:
Further research on the effectiveness of delirium management strategies in the terminal phase for patients and their families is required. Further validation of assessment tools for diagnostic screening and severity measurement are needed in this patient population
Detecting delirium superimposed on dementia: diagnostic accuracy of a simple combined arousal and attention testing procedure
Detecting delirium superimposed on dementia (DSD) can be challenging because assessment partly relies on cognitive tests that may be abnormal in both conditions. We hypothesized that a combined arousal and attention testing procedure would accurately detect DSD.
Patients aged â„70 years were recruited from five hospitals across Europe. Delirium was diagnosed by physicians using DSM-5 criteria using information from nurses, carers, and medical records. Dementia was ascertained by the Informant Questionnaire on Cognitive Decline in the Elderly. Arousal was measured using the Observational Scale of Level of Arousal (OSLA), which assesses eye opening, eye contact, posture, movement, and communication. Attention was measured by participants signaling each time an âAâ was heard when âS-A-V-E-A-H-A-A-R-Tâ was read out.
The sample included 114 persons (mean age 82 years (SD 7); 54% women). Dementia alone was present in 25% (n = 28), delirium alone in 18% (n = 21), DSD in 27% (n = 31), and neither in 30% (n = 34). Arousal and attention was assessed in n = 109 (96%). Using OSLA, 83% participants were correctly identified as having delirium (sensitivity 85%, specificity 82%, AUROC 0.92). The attention task correctly classified 76% of participants with delirium (sensitivity 90%, specificity 64%, AUROC 0.80). Combining scores correctly classified 91% of participants with delirium (sensitivity 84%, specificity 92%, AUROC 0.94). Diagnostic accuracy remained high in the subgroup with dementia (93% correctly classified, sensitivity 94%, specificity 92%, AUROC 0.98).
This combined arousalâattention assessment to detect DSD was brief yet had high diagnostic accuracy. Such an approach could have clinical utility for diagnosing DSD
Development of a SiPM Camera for a Schwarzschild-Couder Cherenkov Telescope for the Cherenkov Telescope Array
We present the development of a novel 11328 pixel silicon photomultiplier
(SiPM) camera for use with a ground-based Cherenkov telescope with
Schwarzschild-Couder optics as a possible medium-sized telescope for the
Cherenkov Telescope Array (CTA). The finely pixelated camera samples air-shower
images with more than twice the optical resolution of cameras that are used in
current Cherenkov telescopes. Advantages of the higher resolution will be a
better event reconstruction yielding improved background suppression and
angular resolution of the reconstructed gamma-ray events, which is crucial in
morphology studies of, for example, Galactic particle accelerators and the
search for gamma-ray halos around extragalactic sources. Packing such a large
number of pixels into an area of only half a square meter and having a fast
readout directly attached to the back of the sensors is a challenging task. For
the prototype camera development, SiPMs from Hamamatsu with through silicon via
(TSV) technology are used. We give a status report of the camera design and
highlight a number of technological advancements that made this development
possible.Comment: 8 pages, 5 figures, In Proceedings of the 34th International Cosmic
Ray Conference (ICRC2015), The Hague, The Netherlands. All CTA contributions
at arXiv:1508.0589
Patient and physician preferences for surgical and adjuvant treatment options for rectal cancer
Hypothesis Patients and their clinicians hold varying preferences for surgical and adjuvant treatment therapies for rectal cancer.
Design Preferences were determined using the Prospective Measure of Preference.
Setting Royal Prince Alfred and St Vincent\u27s hospitals in Sydney, Australia.
Participants Patients with colorectal cancer were interviewed during their postoperative hospital stay, and physicians were asked to complete a mailed survey.
Main Outcome Measures The Prospective Measure of Preference method produces 2 outcome measures of preference: willingness to trade and prospective measure of preference time trade-off.
Results Patients\u27 strongest preference was to avoid a stoma: more than 60% would give up a mean of 34% of their life expectancy to avoid this surgical option. This was followed by treatment options involving chemoradiotherapy, where more than 50% would give up a mean of almost 25% of their life to avoid treatment. Surgeons held stronger preferences against all adjuvant options compared with oncologists (P †.01).
Conclusions Patients had strong preferences against all treatment options, and these preferences frequently differed from those of physicians. These results highlight the importance of determining patients\u27 own preferences in the clinical encounter. Furthermore, the diversity of preferences of clinical subspecialists emphasizes the need for multidisciplinary treatment planning to ensure a balanced approach to treatment decision making for patients with rectal cancer
Nighttime removal of NOx in the summer marine boundary layer
The nitrate radical, NO3, and dinitrogen pentoxide, N2O5, are two important components of nitrogen oxides that occur predominantly at night in the lower troposphere. Because a large fraction of NO2 reacts to form NO3 and N2O5 during the course of a night, their fate is an important determining factor to the overall fate of NOx (=NO and NO2). As a comprehensive test of nocturnal nitrogen oxide chemistry, concentrations of O3, NO, NO2, NO3, N2O5, HNO3 and a host of other relevant compounds, aerosol abundance and composition, and meteorological conditions were measured in the marine boundary layer from the NOAA research vessel Ronald H. Brown off the East Coast of the United States as part of the New England Air Quality Study (NEAQS) during the summer of 2002. The results confirm the prominent role of NO3 and N2O5 in converting NOx to HNO3 at night with an efficiency on par with daytime photochemical conversion. The findings demonstrate the large role of nighttime chemistry in determining the NOx budget and consequent production of ozone. INDEX TERMS: 0322 Atmospheric Composition and Structure: Constituent sources and sinks; 0345 Atmospheric Composition and Structure: Pollutionâurban and regional (0305); 0365 Atmospheric Composition and Structure: Troposphereâcomposition and chemistry. Citation: Brown, S. S., et al. (2004), Nighttime removal of NOx in the summer marine boundary layer, Geophys. Res. Lett., 31, L07108, doi:10.1029/2004GL01941
Altered cortical brain activity in end stage liver disease assessed by multi-channel near-infrared spectroscopy: associations with delirium
Ethical considerations when involving older people in public service participation processes
In the United Kingdom, as in many other countries, New Labour governments have heavily promoted different forms of âservice-user involvementâ in decision making about public services. The current orthodoxy would appear to be that involvement activities carry with them de facto benefits that are both affirmative and empowering. However, relatively little research has been carried out into considering the real impact (emotional or otherwise) of involving citizens in such processes. In this paper, the findings from a small-scale qualitative study led the authors to reflect that when outcomes of consultation are undesired and that when the precise role of those involved is left unclear in terms of purpose, responsibility and accountability, people can be left with powerful, often uncomfortable, feelings. The ethical dimensions of involving people without adequate, prior preparation or ongoing support are discussed, with suggestions made as to how public organisations can take an ethically sound approach to participation. Drawing on research ethics, and informed by the ethics of care, methods through which the potentially harmful effects of involvement can be mitigated are proposed
Mixed-methods research: Whatâs in it for economists?
Empirical studies in economics traditionally use a limited range of methods, usually based on particular types of regression analysis. Increasingly, sophisticated regression techniques require the availability of appropriate data sets, often longitudinal and typically collected at a national level. This raises challenges for researchers seeking to investigate issues requiring data that are not typically included in regular large-scale data. It also raises questions of the adequacy of relying mainly or solely on regression analysis for investigating key issues of economic theory and policy. One way of addressing these issues is to employ a mixed-methods research framework to investigate important research questions. In this article, we provide an example of applying a mixed-methods design to investigate the employment decisions of mature age women working in the aged care sector. We outline the use of a coherent and robust framework to allow the integrated collection and analysis of quantitative and qualitative data. Drawing on particular examples from our analysis, we show how a mixed-methods approach facilitates richer insights, more finely grained understandings of causal relationships and identification of emergent issues. We conclude that mixed-methods research has the capacity to provide surprises and generate new insights through detailed exploratory data analysis
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