742 research outputs found
The Generalized Laguerre Matrix Method or Solving Linear Differential-Difference Equations with Variable Coefficients
In this paper, a new and efficient approach based on the generalized Laguerre matrix method for numerical approximation of the linear differential-difference equations (DDEs) with variable coefficients is introduced. Explicit formulae which express the generalized Laguerre expansion coefficients for the moments of the derivatives of any differentiable function in terms of the original expansion coefficients of the function itself are given in the matrix form. In the scheme, by using this approach we reduce solving the linear differential equations to solving a system of linear algebraic equations, thus greatly simplify the problem. In addition, several numerical experiments are given to demonstrate the validity and applicability of the method
Study of Intraventricular Hemorrhage in VLBW Neonates Admitted in Al-Zahra Hospital, Tabriz, Iran
Introduction and Aim: Intra-ventricular hemorrhage (IVH) is an important predictor of adverse neurodevelopmental outcome. IVH risk factor identification may conduct improvement of quality of care in Neonatal Intensive Care Units. The aim of the current study was to determine possible risk factors associated with IVH in VLBW neonates admitted in our hospital. Patients and Methods: All neonates with birth weight below 1500 gr admitted to NICU. Cranial ultrasonography was done for premature neonates weighed <1000 g in 3 to 5 days and in 1 month again. In premature infants weighed >1000 g, sonography was done in 7 days and 30 days of life respectively. If there is any conditions such as apnea, seizure, significant decrease in level of hemoglobin, increased head circumference, increased oxygen consumption, and other significant changes another sonography was done again. Exclusion criteria were cerebral malformations, metabolic disturbances, chromosomal anomalies, central nervous system infection, and genetic syndromes. Data was analyzed by SPSS ver 16.0 (SPSS Inc, Chicago, IL, USA) Results: In this study 64 cases with IVH and 110 without IVH were included. Mean of gestational age was 28.78±2.08. From neonates, 54.6% were boys and 45.4% were girls. Vaginal delivery and cesarean section was done in 56 (32.2%) and 118(67.8%) cases respectively. Mean±SD of pH in cases with IVH and without IVH was 7.19±0.22 and 7.30±0.12 respectively(p=0.001). Mean ±SD of pco2 in cases with IVH and without IVH was 65.15±29.89 and 49.88±40.89 respectively(p=0.001). Mean of 5th min APGAR score in patients required CPR was 7.36±1.57 and in patients without CPR was 8.68±1.25(P=0.001). From cases with IVH, hydrocephaly was detected in 20 cases. From cases without IVH, hydrocephaly was detected in 6 cases. Result of chi-square showed significant correlation between IVH and prematurity( X2=21.94, df=1, P<0.001). From cases with IVH, 18 cases (28.1%) expired. From cases without IVH, 11 cases(10%) expired(X2=9.398, df=1, P=0.002). Results of chi-square test showed that there were a correlation between IVH and PDA, pressure support, surfactant therapy, inotrop drug administration, vaginal delivery, neonatal resuscitation, and antenatal corticosteroid therapy(p<0.05). Hyaline membrane disease, history of preclampsia in mother was significantly higher in cases without IVH(Chi-square, p<0.05). Conclusion: PDA, pressure support, surfactant therapy, inotrop drug administration, vaginal delivery, neonatal resuscitation, and antenatal corticosteroid therapy were significantly higher in cases with IVH. Hyaline membrane disease and preeclampsia in mother was significantly higher in cases without IVH.Keywords: Intraventricular hemorrhage, APGAR, low birth weight, hyaline membrane disease, corticosteroid, surfactant, inotrop, pre-eclampsi
Electron-phonon relaxation and excited electron distribution in zinc oxide and anatase
We propose a first-principle method for evaluations of the time-dependent
electron distribution function of excited electrons in the conduction band of
semiconductors. The method takes into account the excitations of electrons by
external source and the relaxation to the bottom of conduction band via
electron-phonon coupling. The methods permits calculations of the
non-equilibrium electron distribution function, the quasi-stationary
distribution function with steady-in-time source of light, the time of setting
of the quasi-stationary distribution and the time of energy loss via relaxation
to the bottom of conduction band. The actual calculations have been performed
for titanium dioxide in the anatase structure and zinc oxide in the wurtzite
structure. We find that the quasi-stationary electron distribution function for
ZnO is a fermi-like curve that rises linearly with increasing excitation energy
whereas the analogous curve for anatase consists of a main peak and a shoulder.
The calculations demonstrate that the relaxation of excited electrons and the
setting of the quasi-stationary distribution occur within the time no more than
500 fsec for ZnO and 100 fsec for anatase.
We also discuss the applicability of the effective phonon model with
energy-independent electron-phonon transition probability. We find that the
model only reproduces the trends in changing of the characteristic times
whereas the precision of such calculations is not high. The rate of energy
transfer to phonons at the quasi-stationary electron distribution also have
been evaluated and the effect of this transfer on the photocatalyses has been
discussed. We found that for ZnO this rate is about 5 times less than in
anatase.Comment: 21 p., 9 figure
Dabco containing acidic poly(ionic liquid): An efficient catalyst for the one-pot Preparation of 2,3-dihydroquinazoline-4(1H)-ones
1,4-Diazabicyclo[2.2.2]octane (DABCO) containing acidic poly(ionic liquid) (DAIL) has been prepared via condensation of 1,4-dichloro butane and DABCO, as an efficient acidic catalyst and has been applied in the one-pot preparation of 2,3-dihydroquinazolin-4(1H)-one derivatives. This catalyst has been characterized by FT-IR and TGA. According to the obtained results including time, yield and recyclability, DAIL could be considered as an efficient catalyst for organic transformations
Comparing performance of Tabriz obstetrics and gynaecology hospitals managed as autonomous and budgetary units using Pabon Lasso method
Background: Considering governmental scrutiny and financial constraints in medicine, the need for improved performance, which can provide acceptable care for medical consumers, leads to the conduct of new managerial methods to improve effectiveness. Aims: This study aimed to compare performance indicators of obstetrics and gynaecology teaching hospitals in Tabriz. Method: A longitudinal, retrospective study was conducted to compare performance indexes of Tabriz obstetrics and gynaecology teaching hospitals during 2010-2012. Al-Zahra is Tabriz's central teaching hospital in obstetrics and gynaecology that is authorised under a board of trustees as an autonomous hospital and Taleghani hospital is managed under centralised administration. Study variables included: Average Length of Stay (ALOS), Bed Occupancy Rate (BOR), and Bed Turnover Ratio (BTR). The data was extracted via the Hospital Information Systems (HIS) within the hospitals' admission and discharge units. Pabon Lasso model was used to assess hospital performance. Data was analysed and graphs were plotted using the SPSS-17 software package. Results: According to study findings, overall ALOS in Al-Zahra hospital is 3.15 (2.15) days (1.88 (0.97) days for prenatal wards and 6.13 (0.97) days for neonatal wards) and ALOS in Taleghani Hospital is 3.37 (3.09) days (1.74 (0.14) days for perinatal wards and 5.96 (3.55) days for neonatal wards). In this regard, Al-Zahra hospital holds the maximum BOR with 86.92 per cent and the minimum BOR was attributed to Taleghani hospital at 68.44 per cent (P<0.001). Study findings indicate that BOR in neonatal wards is greater than prenatal wards. On the other hand, BOR in Al-Zahra is greater than Taleghani (P<0.001), whereas BOR trend shows an increasing pattern in both hospitals. Conclusion: Results of this study showed that the performance of Al- Zahra Hospital is better than Taleghani Hospital. These two hospitals are similar in different aspects except Al-Zahra is under a board of trustees and Taleghani is not. We should also consider that Al-Zahra Hospital has more facilities than Taleghani
A novel ensemble artificial intelligence approach for gully erosion mapping in a semi-arid watershed (Iran)
© 2019 by the authors. Licensee MDPI, Basel, Switzerland. In this study, we introduced a novel hybrid artificial intelligence approach of rotation forest (RF) as a Meta/ensemble classifier based on alternating decision tree (ADTree) as a base classifier called RF-ADTree in order to spatially predict gully erosion at Klocheh watershed of Kurdistan province, Iran. A total of 915 gully erosion locations along with 22 gully conditioning factors were used to construct a database. Some soft computing benchmark models (SCBM) including the ADTree, the Support Vector Machine by two kernel functions such as Polynomial and Radial Base Function (SVM-Polynomial and SVM-RBF), the Logistic Regression (LR), and the Naïve Bayes Multinomial Updatable (NBMU) models were used for comparison of the designed model. Results indicated that 19 conditioning factors were effective among which distance to river, geomorphology, land use, hydrological group, lithology and slope angle were the most remarkable factors for gully modeling process. Additionally, results of modeling concluded the RF-ADTree ensemble model could significantly improve (area under the curve (AUC) = 0.906) the prediction accuracy of the ADTree model (AUC = 0.882). The new proposed model had also the highest performance (AUC = 0.913) in comparison to the SVM-Polynomial model (AUC = 0.879), the SVM-RBF model (AUC = 0.867), the LR model (AUC = 0.75), the ADTree model (AUC = 0.861) and the NBMU model (AUC = 0.811)
Quantum Fluctuation Theorems
Recent advances in experimental techniques allow one to measure and control
systems at the level of single molecules and atoms. Here gaining information
about fluctuating thermodynamic quantities is crucial for understanding
nonequilibrium thermodynamic behavior of small systems. To achieve this aim,
stochastic thermodynamics offers a theoretical framework, and nonequilibrium
equalities such as Jarzynski equality and fluctuation theorems provide key
information about the fluctuating thermodynamic quantities. We review the
recent progress in quantum fluctuation theorems, including the studies of
Maxwell's demon which plays a crucial role in connecting thermodynamics with
information.Comment: As a chapter of: F. Binder, L. A. Correa, C. Gogolin, J. Anders, and
G. Adesso (eds.), "Thermodynamics in the quantum regime - Fundamental Aspects
and New Directions", (Springer International Publishing, 2018
Anticonvulsant effects of aerial parts of Passiflora incarnata extract in mice: involvement of benzodiazepine and opioid receptors
<p>Abstract</p> <p>Background</p> <p>Passion flower (<it>Passiflora incarnata</it>) is used in traditional medicine of Europe and South America to treat anxiety, insomnia and seizure. Recently, it has shown antianxiety and sedative effects in human.</p> <p>Methods</p> <p>In this study, anticonvulsant effects of hydro- alcoholic extract of Passiflora, Pasipay, were examined by using pentylentetrazole model (PTZ) on mice. Pasipay, diazepam, and normal saline were injected intraperitoneally at the doses 0.4–0.05 mg/kg, 0.5–1 mg/kg and 10 ml/kg respectively 30 minutes before PTZ (90 mg/kg, i.p). The time taken before the onset of clonic convulsions, the duration of colonic convulsions, and the percentage of seizure and mortality protection were recorded. For investigating the mechanism of Pasipay, flumazenil (2 mg/kg, i.p) and naloxone (5 mg/kg, i.p) were also injected 5 minutes before Pasipay.</p> <p>Results</p> <p>An ED<sub>50 </sub>value of Pasipay in the PTZ model was 0.23 mg/kg (%95 CL: 0.156, 0.342). Pasipay at the dose of 0.4 mg/kg prolonged the onset time of seizure and decreased the duration of seizures compared to saline group (p < 0.001). At the dose of 0.4 mg/kg, seizure and mortality protection percent were 100%. Flumazenil and naloxone could suppress anticonvulsant effects of Pasipay.</p> <p>Conclusion</p> <p>It seems that Pasipay could be useful for treatment absence seizure and these effects may be related to effect of it on GABAergic and opioid systems. More studies are needed in order to investigate its exact mechanism.</p
Detection of regulator genes and eQTLs in gene networks
Genetic differences between individuals associated to quantitative phenotypic
traits, including disease states, are usually found in non-coding genomic
regions. These genetic variants are often also associated to differences in
expression levels of nearby genes (they are "expression quantitative trait
loci" or eQTLs for short) and presumably play a gene regulatory role, affecting
the status of molecular networks of interacting genes, proteins and
metabolites. Computational systems biology approaches to reconstruct causal
gene networks from large-scale omics data have therefore become essential to
understand the structure of networks controlled by eQTLs together with other
regulatory genes, and to generate detailed hypotheses about the molecular
mechanisms that lead from genotype to phenotype. Here we review the main
analytical methods and softwares to identify eQTLs and their associated genes,
to reconstruct co-expression networks and modules, to reconstruct causal
Bayesian gene and module networks, and to validate predicted networks in
silico.Comment: minor revision with typos corrected; review article; 24 pages, 2
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