3,236 research outputs found
Saving Energy in Mobile Devices for On-Demand Multimedia Streaming -- A Cross-Layer Approach
This paper proposes a novel energy-efficient multimedia delivery system
called EStreamer. First, we study the relationship between buffer size at the
client, burst-shaped TCP-based multimedia traffic, and energy consumption of
wireless network interfaces in smartphones. Based on the study, we design and
implement EStreamer for constant bit rate and rate-adaptive streaming.
EStreamer can improve battery lifetime by 3x, 1.5x and 2x while streaming over
Wi-Fi, 3G and 4G respectively.Comment: Accepted in ACM Transactions on Multimedia Computing, Communications
and Applications (ACM TOMCCAP), November 201
Surgical challenges of down syndrome with developmental dislocation or dysplasia of the hip undergo operative treatment under anaesthesia in teaching hospital
Developmental/dislocation of the hip is one of the orthopaedic issues and the most common problem of the hip in down syndrome (DS). Down syndrome often arises with its general laxity problematics, one of the things is developmental dislocation/dysplasia of the hip (DDH). In chronic cases, surgery is a must, and this is mentions in several journals. Some complications can occur in the process of anaesthesia with intubation. We report two cases, both of which are seven years old with patients in the first case experiencing DDH and patients in the second case experiencing dislocation. The first patient had open reduction surgery with capsulotomy and internal fixation. The second patient, close reduction, and hemi spica installation. The first patient has trouble breathing one week after surgery, and then the tracheotomy is performed. A tracheotomy performed for almost two months and hemi spica removed in September 2019. After hemi spica removal, the patients were then routinely controlled for rehabilitation polyclinics, and the results improved
Diffusion-emission theory of photon enhanced thermionic emission solar energy harvesters
Numerical and semi-analytical models are presented for
photon-enhanced-thermionic-emission (PETE) devices. The models take diffusion
of electrons, inhomogeneous photogeneration, and bulk and surface recombination
into account. The efficiencies of PETE devices with silicon cathodes are
calculated. Our model predicts significantly different electron affinity and
temperature dependence for the device than the earlier model based on a
rate-equation description of the cathode. We show that surface recombination
can reduce the efficiency below 10% at the cathode temperature of 800 K and the
concentration of 1000 suns, but operating the device at high injection levels
can increase the efficiency to 15%.Comment: 5 pages, 4 figure
Metal Recovery and Preconcentration by Aminopolycarboxylic Acid modified Silica Surfaces
This study focuses on the adsorption and preconcentration of various metals by silica gel surfaces modified with aminopolycarboxylic acids namely ethylenediaminetetraacetic acid or diethylenetriamine-pentaacetic acid. The adsorption performance of the studied materials was determined in mixed metal solutions and the adsorption isotherm studies were conducted for cobalt, nickel, cadmium, and lead. The results were modeled using various theoretical isotherm equations, which suggested that two different adsorption sites were involved in metal removal although lead showed clearly different adsorption behavior attributed to its lowest hydration tendency. Efficient regeneration of the adsorbents and preconcentration of metals was conducted with nitric acid. Results
indicated that the metals under study could be analyzed rather accurately after preconcentration from both pure, saline and ground water samples
Correction to: Perinatal outcomes in Finnish twins : a retrospective study
An amendment to this paper has been published and can be accessed via the original article
Perinatal outcome of dichorionic and monochorionic-diamniotic Finnish twins : a historical cohort study
Introduction Although the perinatal mortality of monochorionic twins has been reported to be higher, the role of chorionicity is debated and data from Finland are still lacking. To examine the effect of chorionicity on the main outcome measures, perinatal and neonatal mortality and neonatal morbidity of Finnish twins, a comprehensive population-based historical cohort study was performed at Helsinki University Hospitals. Material and methods All 1034 dichorionic and monochorionic-diamniotic twin pregnancies managed at Helsinki University Hospital area during 2006, 2010, 2014 and 2018 were collected from patient databases. Information on chorionicity was retrieved from ultrasound reports and all relevant clinical information from patient records. Differences in perinatal and neonatal mortality and neonatal morbidity were analyzed by performing group comparisons between the twins and chorionicity. The role of chorionicity was also assessed in logistic regression analyses. Results There were 1034 dichorionic-diamniotic (DCDA, n = 789, 76.3%, 95% confidence interval [CI] 73.6-78.9) and monochorionic-diamniotic (MCDA, n = 245, 23.7%, 95% CI 21.4-26.0) twin pregnancies during the studied years. Most (n = 580, 56.1%, 95% CI 52.8-59.2) twins were born at term, but 151 (61.6%, 95% CI 55.8-67.3) of MCDA twins were preterm and had lower birthweight and Apgar scores and higher risk of death of one twin. Perinatal and neonatal mortality did not differ between twins A and B, but the immediate outcome of twin B was worse, with lower arterial pH and Apgar scores and increased need of neonatal intensive care unit treatment. Conclusions Chorionicity contributes to the perinatal and neonatal outcome in favor of dichorionic twins. This disadvantage of MCDA twinning is likely explained by earlier gestational age at birth and inequal placental sharing. Irrespective of chorionicity, twin B faces more complications.Peer reviewe
Operator-sum representation of time-dependent density operators and its applications
We show that any arbitrary time-dependent density operator of an open system
can always be described in terms of an operator-sum representation regardless
of its initial condition and the path of its evolution in the state space, and
we provide a general expression of Kraus operators for arbitrary time-dependent
density operator of an -dimensional system. Moreover, applications of our
result are illustrated through several examples.Comment: 4 pages, no figure, brief repor
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