1,861 research outputs found
Rotating Black Holes and Coriolis Effect
In this work, we consider the fluid/gravity correspondence for general
rotating black holes. By using the Petrov-like boundary condition in near
horizon limit, we study the correspondence between gravitational perturbation
and fluid equation. We find that the dual fluid equation for rotating black
holes contains a Coriolis force term, which is closely related to the angular
velocity of the black hole horizon. This can be seen as a dual effect for the
frame-dragging effect of rotating black hole under the holographic picture.Comment: 5 page
The research of hidden Markov models for overall equipment effectiveness analysis in smart manufacturing system
In the manufacturing industry, excellent product quality and increased production flexibility can be achieved by eliminating waste and improving production efficiency. In the past, the manufacturing industry used manual records of production information, but this method is characterized by low efficiency and high error rates. Even if a programmable logic controller and radio-frequency identification are employed, problems still occur because of constraints such as different machine types and high costs. The use of a cyber–physical system and information visualization requires the collection of manufacturing information in order to facilitate the analysis of manufacturing data. Monitoring the machining status. This study proposes an approach for segmenting machine-processed signals. With plug-and-play noninvasive current-sensing equipment to collect machine production information, this approach can immediately determine the state of the manufacturing process and calculate the machine utilization, machine production cycle, and production quantity. The goal is to enable the use of this method with this equipment, improve machine utilization, instantly identify the production quantity, and reduce equipment idle time to reduce manufacturing waste, thus rendering production management more convenient and faster
A Simple Model for Cavity Enhanced Slow Lights in Vertical Cavity Surface Emission Lasers
We develop a simple model for the slow lights in Vertical Cavity Surface
Emission Lasers (VCSELs), with the combination of cavity and population
pulsation effects. The dependences of probe signal power, injection bias
current and wavelength detuning for the group delays are demonstrated
numerically and experimentally. Up to 65 ps group delays and up to 10 GHz
modulation frequency can be achieved in the room temperature at the wavelength
of 1.3 m. The most significant feature of our VCSEL device is that the
length of active region is only several m long. Based on the experimental
parameters of quantum dot VCSEL structures, we show that the resonance effect
of laser cavity plays a significant role to enhance the group delays
Major interventions are associated with survival of out of hospital cardiac arrest patients - a population based survey
Background. The overall survival rate of
out-of-hospital cardiac arrest (OHCA)
in Taiwan or even in the whole of Asia
is relatively low. Major interventions,
such as target temperature management
(TTM), coronary artery angiography, and
extracorporeal membrane oxygenation
(ECMO), have been associated with better
patient outcome. However, studies in Taiwan
revealing evidence of the benefits of
these interventions are limited.
Methods. A population-based study used
an 8-year database to analyze overall survival
and risk factors Ëťamong OHCA patients.
All adult non-trauma OHCA patients
were identified through diagnostic
and procedure codes. Hospital survival
and return of spontaneous circulation
(ROSC) were primary and secondary outcomes.
Logistic regression and Cox regression
analyses were conducted.
Results. There was a relationship between
major interventions (including TTM,
coronary artery angiography, and ECMO)
and better hospital survival. Age, income,
major interventions, and acute myocardial
infarction history were associated with
hospital survival. The adjusted hazard
ratios (HRs) were 0.406 (95% CI, 0.295
to 0.558), 1.109 (95% CI, 1.027 to 1.197),
1.075 (95% CI, 1.002 to 1.154), 1.097 (95%
CI, 1.02 to 1.181) and 0.799(95% CI, 0.677
to 0.942) for patients with major interventions,
age≥50, medium low and low income,
middle income, and acute myocardial
infarction history, respectively.
Conclusion. This population-based study
in Taiwan revealed that older age (≥50),
medium low and low income were associated
with a lower rate of survival. Major
interventions, including TTM, coronary
angiography, and ECMO, were related to
better survival
Examination Of The Influence Of Service Quality On Membership Renewal In Fitness Centers In San Francisco Bay Area
Corporations have to learn how to satisfy their customers’ various demands as the era of interactivity with customers has emerged (Pepper & Rogers, 1999). For fitness center, customers’ demands are increasing and diversified. Therefore, service quality is an index of quality assessment from customers for service-producing industries. Furthermore, the concept of corporate expansion and customer relationship has become the foundation of service-providers for higher profitability through customers’ renewal of membership. The main purpose of this study is to evaluate the impact of service quality on the renewal willingness of fitness center membership. Customers from four fitness centers in the San Francisco Bay Area, USA, were randomly selected for this survey. A total of 50 subjects participated in this survey. The data was analyzed by multiple regression and stepwise regression. The result indicated that the service quality has positive influence on the renewal willingness of membership
Comparing the outcomes of two strategies for colorectal tumor detection: Policy-promoted screening program versus health promotion service
AbstractBackgroundThe Taiwanese government has proposed a population-based colorectal tumor detection program for the average-risk population. This study's objectives were to understand the outcomes of these screening policies and to evaluate the effectiveness of the program.MethodsWe compared two databases compiled in one medical center. The “policy-promoted cancer screening” (PPS) database was built on the basis of the policy of the Taiwan Bureau of National Health Insurance for cancer screening. The “health promotion service” (HPS) database was built to provide health check-ups for self-paid volunteers. Both the PPS and HPS databases employ the immunochemical fecal occult blood test (iFOBT) and colonoscopy for colorectal tumor screening using different strategies. A comparison of outcomes between the PPS and HPS included: (1) quality indicators—compliance rate, cecum reaching rate, and tumor detection rate; and (2) validity indicators—sensitivity, specificity, positive, and negative predictive values for detecting colorectal neoplasms.ResultsA total of 10,563 and 1481 individuals were enrolled in PPS and HPS, respectively. Among quality indicators, there was no statistically significant difference in the cecum reaching rate between PPS and HPS. The compliance rates were 56.1% for PPS and 91.8% for HPS (p < 0.001). The advanced adenoma detection rates of PPS and HPS were 1.0% and 3.6%, respectively (p < 0.01). The carcinoma detection rates were 0.3% and 0.4%, respectively (p = 0.59). For validity indicators, PPS provides only a positive predictive value for colorectal tumor detection. HPS provides additional validity indicators, including sensitivity, specificity, positive predictive value, and negative predictive value, for colorectal tumor screening.ConclusionIn comparison with the outcomes of the HPS database, the screening efficacy of the PPS database is even for detecting colorectal carcinoma but is limited in detecting advanced adenoma. HPS may provide comprehensive validity indicators and will be helpful in adjusting current policies for improving screening performance
Prenatal Diagnosis of Pulmonary Sequestration by Ultrasound and Magnetic Resonance Imaging
A 36-year-old multigravida, G2P1, underwent routine ultrasound scan at 22+1 weeks of gestation, which revealed a single normally growing fetus with left intrathoracic mass and left displacement of the cardiac apex. The left intrathoracic wedge-shaped hyperechogenic mass, measuring 32 Ă— 25 mm in size, was situated at the lower portion of the left lung. A combination of color and power Doppler ultrasound allowed visualization of a vessel arising from the descending aorta, which supplied the mass. The diagnosis of extralobar pulmonary sequestration was made. Magnetic resonance imaging (MRI) was also performed and revealed a well-defined mass with homogeneous high-signal intensity when compared with normal lung tissue in the left upper lung field, which was compatible with pulmonary sequestration. The pulmonary mass was followed up by color and power Doppler every 2 weeks. The peak velocity of 11.85 cm/sec and the diameter of the feeding artery of 1.19 mm gradually decreased and disappeared 8 weeks later. The intrathoracic mass disappeared 10 weeks later at 32+1 gestational weeks. Repeat MRI also revealed spontaneous regression of the mass in favor of resorption of sequestration. The fetus was delivered at 38+1 gestational weeks. A male newborn weighing 2,520 g was spontaneously delivered with an Apgar score of 8 at 1 minute and 9 at 5 minutes. In our patient, it is suggested that progressive decreases in the peak velocity of the feeding vessel heralded the spontaneous regression of pulmonary sequestration not associated with hydrops/hydrothorax
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