3,216 research outputs found
Event-based knowledge elicitation of operating room management decision-making using scenarios adapted from information systems data
<p>Abstract</p> <p>Background</p> <p>No systematic process has previously been described for a needs assessment that identifies the operating room (OR) management decisions made by the anesthesiologists and nurse managers at a facility that do not maximize the efficiency of use of OR time. We evaluated whether event-based knowledge elicitation can be used practically for rapid assessment of OR management decision-making at facilities, whether scenarios can be adapted automatically from information systems data, and the usefulness of the approach.</p> <p>Methods</p> <p>A process of event-based knowledge elicitation was developed to assess OR management decision-making that may reduce the efficiency of use of OR time. Hypothetical scenarios addressing every OR management decision influencing OR efficiency were created from published examples. Scenarios are adapted, so that cues about conditions are accurate and appropriate for each facility (e.g., if OR 1 is used as an example in a scenario, the listed procedure is a type of procedure performed at the facility in OR 1). Adaptation is performed automatically using the facility's OR information system or anesthesia information management system (AIMS) data for most scenarios (43 of 45). Performing the needs assessment takes approximately 1 hour of local managers' time while they decide if their decisions are consistent with the described scenarios. A table of contents of the indexed scenarios is created automatically, providing a simple version of problem solving using case-based reasoning. For example, a new OR manager wanting to know the best way to decide whether to move a case can look in the chapter on "Moving Cases on the Day of Surgery" to find a scenario that describes the situation being encountered.</p> <p>Results</p> <p>Scenarios have been adapted and used at 22 hospitals. Few changes in decisions were needed to increase the efficiency of use of OR time. The few changes were heterogeneous among hospitals, showing the usefulness of individualized assessments.</p> <p>Conclusions</p> <p>Our technical advance is the development and use of automated event-based knowledge elicitation to identify suboptimal OR management decisions that decrease the efficiency of use of OR time. The adapted scenarios can be used in future decision-making.</p
Body mass index and incident coronary heart disease in women: a population-based prospective study
BACKGROUND A high body mass index (BMI) is associated with an increased risk of mortality from coronary heart disease (CHD); however, a low BMI may also be associated with an increased mortality risk. There is limited information on the relation of incident CHD risk across a wide range of BMI, particularly in women. We examined the relation between BMI and incident CHD overall and across different risk factors of the disease in the Million Women Study. METHODS 1.2 million women (mean age=56 years) participants without heart disease, stroke, or cancer (except non-melanoma skin cancer) at baseline (1996 to 2001) were followed prospectively for 9 years on average. Adjusted relative risks and 20-year cumulative incidence from age 55 to 74 years were calculated for CHD using Cox regression. RESULTS After excluding the first 4 years of follow-up, we found that 32,465 women had a first coronary event (hospitalization or death) during follow-up. The adjusted relative risk for incident CHD per 5 kg/m2 increase in BMI was 1.23 (95% confidence interval (CI) 1.22 to 1.25). The cumulative incidence of CHD from age 55 to 74 years increased progressively with BMI, from 1 in 11 (95% CI 1 in 10 to 12) for BMI of 20 kg/m2, to 1 in 6(95% CI 1 in 5 to 7) for BMI of 34 kg/m2. A 10 kg/m2 increase in BMI conferred a similar risk to a 5-year increment in chronological age. The 20 year cumulative incidence increased with BMI in smokers and non-smokers, alcohol drinkers and non-drinkers, physically active and inactive, and in the upper and lower socioeconomic classes. In contrast to incident disease, the relation between BMI and CHD mortality (n=2,431) was J-shaped. For the less than 20 kg/m2 and ≥35 kg/m2 BMI categories, the respective relative risks were 1.27 (95% CI 1.06 to 1.53) and 2.84 (95% CI 2.51 to 3.21) for CHD deaths, and 0.89 (95% CI 0.83 to 0.94) and 1.85 (95% CI 1.78 to 1.92) for incident CHD. CONCLUSIONS CHD incidence in women increases progressively with BMI, an association consistently seen in different subgroups. The shape of the relation with BMI differs for incident and fatal disease.The Million Women Study is funded by Cancer Research UK, the Medical
Research Council, and the NHS Breast Screening Programme. The funding
organizations were not involved in the study design or conduct, data
analysis or interpretation, manuscript preparation or review, final version
approval, or decision to submit the manuscript
Radiative Models of Sagittarius A* and M87 from Relativistic MHD Simulations
Ongoing millimeter VLBI observations with the Event Horizon Telescope allow
unprecedented study of the innermost portion of black hole accretion flows.
Interpreting the observations requires relativistic, time-dependent physical
modeling. We discuss the comparison of radiative transfer calculations from
general relativistic MHD simulations of Sagittarius A* and M87 with current and
future mm-VLBI observations. This comparison allows estimates of the viewing
geometry and physical conditions of the Sgr A* accretion flow. The viewing
geometry for M87 is already constrained from observations of its large-scale
jet, but, unlike Sgr A*, there is no consensus for its millimeter emission
geometry or electron population. Despite this uncertainty, as long as the
emission region is compact, robust predictions for the size of its jet
launching region can be made. For both sources, the black hole shadow may be
detected with future observations including ALMA and/or the LMT, which would
constitute the first direct evidence for a black hole event horizon.Comment: 8 pages, 2 figures, submitted to the proceedings of AHAR 2011: The
Central Kiloparse
Effect of Agronomic Practices on Apparent Sucrose and Invert Sugar Levels During Storage of Sugarbeets (Beta Vulgaris L.)
The quality of sugar beet (Beta vulgaris L. ~ roots stored in open piles deteriorates due to a buildup of impurities t6). Sucrose is lost because of respiration and inversion to glucose and fructose. Invert sugar (glucose and fructose) constitutes a major portion of
the increase of impurities during storage. Storage temperatures affect invert sugar buildup (4). Other variables affecting sucrose loss and invert sugar accumulation are variety, date of harvest and various chemicals. The objectives of this study were to determine the effects of chemicals, supplemental irrigation, nitrogen, and cultivars on invert sugar accumulation and apparent sucrose loss in sugar beet roots stored for 150 days at 5 C. The data indicate the importance of controlling several agronomic practices that affect quality of sugar beet roots during storage. Sucros levels were higher in those sugar beets roots which were treated with three herbicides and a growth regulator when averaged over all sampling dates during storage of the roots
Associated degeneration of ventral tegmental area dopaminergic neurons in the rat nigrostriatal lactacystin model of parkinsonism and their neuroprotection by valproate
AbstractParkinson’s disease (PD) manifests clinically as bradykinesia, rigidity, and development of a resting tremor, primarily due to degeneration of dopaminergic nigrostriatal pathways in the brain. Intranigral administration of the irreversible ubiquitin proteasome system inhibitor, lactacystin, has been used extensively to model nigrostriatal degeneration in rats, and study the effects of candidate neuroprotective agents on the integrity of the dopaminergic nigrostriatal system. Recently however, adjacent extra-nigral brain regions such as the ventral tegmental area (VTA) have been noted to also become affected in this model, yet their integrity in studies of candidate neuroprotective agents in the model have largely been overlooked. Here we quantify the extent and distribution of dopaminergic degeneration in the VTA of rats intranigrally lesioned with lactacystin, and quantify the extent of VTA dopaminergic neuroprotection after systemic treatment with an epigenetic therapeutic agent, valproate, shown previously to protect dopaminergic SNpc neurons in this model. We found that unilateral intranigral administration of lactacystin resulted in a 53.81% and 31.72% interhemispheric loss of dopaminergic SNpc and VTA neurons, respectively. Daily systemic treatment of lactacystin lesioned rats with valproate however resulted in dose-dependant neuroprotection of VTA neurons. Our findings demonstrate that not only is the VTA also affected in the intranigral lactacystin rat model of PD, but that this extra-nigral brain region is substrate for neuroprotection by valproate, an agent shown previously to induce neuroprotection and neurorestoration of SNpc dopaminergic neurons in this model. Our results therefore suggest that valproate is a candidate for extra-nigral as well as intra-nigral neuroprotection
Statistics of X-ray flares of Sagittarius A*: evidence for solar-like self-organized criticality phenomenon
X-ray flares have routinely been observed from the supermassive black hole,
Sagittarius A (Sgr A), at our Galactic center. The nature of
these flares remains largely unclear, despite of many theoretical models. In
this paper, we study the statistical properties of the Sgr A X-ray
flares, by fitting the count rate (CR) distribution and the structure function
(SF) of the light curve with a Markov Chain Monte Carlo (MCMC) method. With the
3 million second \textit{Chandra} observations accumulated in the Sgr A
X-ray Visionary Project, we construct the theoretical light curves through
Monte Carlo simulations. We find that the keV X-ray light curve can be
decomposed into a quiescent component with a constant count rate of
count s and a flare component with a power-law
fluence distribution with . The duration-fluence correlation can also be modelled as a
power-law with (
confidence). These statistical properties are consistent with the theoretical
prediction of the self-organized criticality (SOC) system with the spatial
dimension . We suggest that the X-ray flares represent plasmoid
ejections driven by magnetic reconnection (similar to solar flares) in the
accretion flow onto the black hole.Comment: to appear in Ap
Recommended from our members
Achieving Equity by Building a Bridge From Eligible to Enrolled
Calls for multilingual outreach and enrollment efforts to enable Californians of color and those with limited English proficiency to benefit from the Health Benefit Exchange. Recommends targeting high-need groups and strengthening data collection
Influence of Fluoride on Strength and Elasticity of Femurs of Rats Maintained on Diets both Adequate and Low in Calcium
The effect of fluoride on the physical properties of the rat femur was investigated by using an Instron materials tester. Experimental animals consisting of 80 female weanling rats were employed. These were divided into two major groups of 40 rats each. Group I received adequate calcium in the diet and Group II received a low calcium (0.1%) diet. Group I and II were divided into five subgroups, the first subgroup being used as the control. Each of the other four subgroups was given a different dosage level of fluoride in their drinking water as follows: the second subgroup received Hereford, Texas, drinking water, which contains 3.4 ppm F; the third subgroup received 10.0 ppm F, as sodium fluoride, in deionized water; and the fifth subgroup received 45.0 ppm F, as sodium fluoride, in deionized water.
At 7 and 15 weeks the rats were x-rayed for the determination of bone density, the last x-ray being the time of sacrifice. The left and right femurs were removed, measured, and the shafts tested for strength and elasticity. The broken ends were photograph for volume and cortical thickness determination. In addition, the demur shafts were assayed for fluoride content.
From the tests made, the Load at the Elastic Limit, Maximum Load and Load at Breaking Point with their corresponding deflections were recorded. Using the above results, the Stress for each load, Energy Absorbed until breaking, Young\u27s Modulus of Elasticity, Flexibility and Stiffness were calculated. An analysis of variance to determine the difference between means of the variables given above, within the five subgroups, was run. For the variables that showed significant differences between subgroups within major groups, t test were run to determine where and to what extent differences were found.
Comparing the results with the controls showed that the rats given an adequate calcium diet with 45.0 ppm F in their drinking water had a slight decrease in breaking strength, but a significantly greater flexibility. The rats given a low calcium diet with 10 ppm F and 45.0 ppm F in their drinking water showed a significant decrease in strength, but increased flexibility at the 10 ppm F level and a highly significant decrease in strength and reciprocal increase in flexibility at the 45.0 ppm F level. This last subgroup also showed a significant increase in the amount of energy absorbed. The results clearly show that, if calcium and the trace element fluorine, as sodium fluoride, are given in adequate, but not excessive amounts, they complement each other in improving the physical properties of bone
The Post-Pericenter Evolution of the Galactic Center Source G2
In early 2014 the fast-moving near-infrared source G2 reached its closest
approach to the supermassive black hole Sgr A* in the Galactic Center. We
report on the evolution of the ionized gaseous component and the dusty
component of G2 immediately after this event, revealed by new observations
obtained in 2015 and 2016 with the SINFONI integral field spectrograph and the
NACO imager at the ESO VLT. The spatially resolved dynamics of the Br
line emission can be accounted for by the ballistic motion and tidal shearing
of a test-particle cloud that has followed a highly eccentric Keplerian orbit
around the black hole for the last 12 years. The non-detection of a drag force
or any strong hydrodynamic interaction with the hot gas in the inner accretion
zone limits the ambient density to less than a few 10 cm at the
distance of closest approach (1500 ), assuming G2 is a spherical cloud
moving through a stationary and homogeneous atmosphere. The dust continuum
emission is unresolved in L'-band, but stays consistent with the location of
the Br emission. The total luminosity of the Br and L' emission
has remained constant to within the measurement uncertainty. The nature and
origin of G2 are likely related to that of the precursor source G1, since their
orbital evolution is similar, though not identical. Both object are also likely
related to a trailing tail structure, which is continuously connected to G2
over a large range in position and radial velocity.Comment: 17 pages, 12 figures; accepted for publication in Ap
- …