719 research outputs found
Transfer learning for predicting source terms of principal component transport in chemically reactive flow
The objective of this study is to evaluate whether the number of requisite
training samples can be reduced with the use of various transfer learning
models for predicting, for example, the chemical source terms of the
data-driven reduced-order model that represents the homogeneous ignition
process of a hydrogen/air mixture. Principal component analysis is applied to
reduce the dimensionality of the hydrogen/air mixture in composition space.
Artificial neural networks (ANNs) are used to tabulate the reaction rates of
principal components, and subsequently, a system of ordinary differential
equations is solved. As the number of training samples decreases at the target
task (i.e.,for T0 > 1000 K and various phi), the reduced-order model fails to
predict the ignition evolution of a hydrogen/air mixture. Three transfer
learning strategies are then applied to the training of the ANN model with a
sparse dataset. The performance of the reduced-order model with a sparse
dataset is found to be remarkably enhanced if the training of the ANN model is
restricted by a regularization term that controls the degree of knowledge
transfer from source to target tasks. To this end, a novel transfer learning
method is introduced, parameter control via partial initialization and
regularization (PaPIR), whereby the amount of knowledge transferred is
systemically adjusted for the initialization and regularization of the ANN
model in the target task. It is found that an additional performance gain can
be achieved by changing the initialization scheme of the ANN model in the
target task when the task similarity between source and target tasks is
relatively low.Comment: 41 pages, 14 figure
Modified Vertical Rectus Abdominis Musculocutaneous Flap for Limb Salvage Procedures in Proximal Lower Limb Musculoskeletal Sarcomas
Introduction and aim. Management of complicated wounds after tumor extipiration of pelvic and proximal lower limb musculoskeletal sarcoma represents an essential component in the outcome of these patients. The authors present modified vertical rectus abdominis musculocutaneous (VRAM) flap techniques to reconstruct extensive defects after debridment of these complicated wounds. Material and Methods. Over a period of 4 years (2002–2005), 5 men and 2 women were managed. Median age was 21 years (range 15–49). The patients were managed for complicated lower trunk, groin, and upper thigh wounds after resection of three pelvic chondrosarcomas as well as two pelvic and two proximal femur osteosarcomas. The modifications included a VRAM flap with lateral and tongue-like extension design of the skin paddle (5 cases) or a delayed extended VRAM flap (2 cases). Results. All flaps showed complete survival and healing with no ischemic events providing stable coverage. All patients were ambulant with good limb functions in terms of walking and gait after adequate rehabilitation, 2 needed support with crutches. Conclusion. The modified VRAM flaps offer reliable reconstructive tools for coverage of complex groin and thigh defects by providing larger well-vascularized soft tissue with acceptable donor site
Evaluation of Global Solar Radiation Estimated from ECMWF-ERA5 and Validation with Measured Data over Egypt
Solar energy is a big source of renewable energy and, luckily, solar energy is very rich in Egypt and the eastern Mediterranean region.The validation of the global solar radiation from the reanalysis data ECMWF-ERA5 by using the parameters from data elements and to deduce a new model to give a good representation of the GSR distribution when compared with measured data. The estimation of global solar radiation (GSR) distribution over Egyptduring the period time from 2017 to 2019. Evaluated and a comparative assessment of the models was carried out using measured GSR at Helwan (29.82 ᵒN, 31.29ᵒE) and Suez(31ᵒN.32ᵒE) sites are done.
Database:The European Center for Middle-Distance Weather Forecast recently released its most complex reanalysis product ERA5 data set (ECMWF). This method has been developed and manufactured, giving it more advantages than ECMWF's previously released ERA-Interim reanalysis products. It has better spatial resolution, can be archived every hour, and uses more advanced assimilation methods and merges more data sources.
The results showed that the model could predict the pattern of the measured monthly, daily mean of GSR for the entire period. The correlation coefficient (R) is equal 95% and 97% of GSR for Helwan and Suez respectively.The outputs from our proposed model for monthly global solar radiation distribution over the period of study is given, and the maximum value 7.5 KWh/m2and the minimum are 3 KWh/m2.The values of RMSE of GSR-ERA5 and GSR-estimated for Helwan and Suez sites are 0.275, 0.446 and 0.2, 0.36 (KWh/m2) respectively. The values of MABE of GSR-ERA5 and GSR-estimated for the two station Helwan and Suez is 0.014, 0.023 and 0.007, 0.03 (KWh/m2) respectively. Finally the proposed model was used to givean indication of theGSR distribution over Egypt
Clinical characteristics of depression among adolescent females: a cross-sectional study
<p>Abstract</p> <p>Background</p> <p>Adolescents rarely seek psychiatric help; they even hesitate to disclose their feelings to their parents. However; the adolescents especially the females experience depressive symptoms more frequently than general population. Do they experience classic depressive symptoms? Are there symptoms specific to this subpopulation?</p> <p>Aim of the study</p> <p>Through this study, the authors aimed to estimate the prevalence of depressive disorders in Egyptian adolescent female students. They also expected a characteristic profile of symptoms for the adolescent females. However available literature provides no guidance in the description of this profile of symptoms.</p> <p>Methods</p> <p>A number of 602 adolescent females were interviewed, and subjected to General Health Questionnaire (GHQ); Children Depression Inventory (CDI), Structured Clinical Interview for DSM-IV Axis-I Disorders (SCID-I), then Hamilton Rating Scale for Depression (Ham-D). Results were analyzed by the use of SPSS-15.</p> <p>Results</p> <p>The study revealed the prevalence of depression in the sample of the study to be 15.3% (measured by CDI), and 13.3% (measured by SCID-I). Fatigue was the most common presenting depressive symptom (81.3%), in addition to other emotional, cognitive and physiological symptoms. Suicidal ideations were the most common suicidal symptoms in depressed adolescent females (20%), with 2.5% serious suicidal attempts.</p> <p>Conclusions</p> <p>The somatic symptoms were by far the most common presenting symptom for female adolescents suffering from depressive disorders. Depressive phenomena including unexplained fatigue, decreased energy, psychomotor changes, lack of concentration, weight changes and suicidal ideations may be the presenting complaints instead of the classic sad mood.</p
A Combined Use of Rhizobacteria and Moringa Leaf Extract Mitigates the Adverse Effects of Drought Stress in Wheat (Triticum aestivum L.)
Less nutrient availability and drought stress are some serious concerns of agriculture. Both biotic and abiotic stress factors have the potential to limit crop productivity. However, several organic extracts obtained from moringa leaves may induce immunity in plants under nutritional and drought stress for increasing their survival. Additionally, some rhizobacterial strains have the ability to enhance root growth for better nutrient and water uptake in stress conditions. To cover the knowledge gap on the interactive effects of beneficial rhizobacteria and moringa leaf extracts (MLEs), this study was conducted. The aim of this experimental study was to investigate the effectiveness of sole and combined use of rhizobacteria and MLEs against nutritional and drought stress in wheat. Nitrogen-fixing bacteria Pseudomonas aeruginosa (Pa) (10(8) CFU ml(-1)) was inoculated to wheat plants with and without foliar-applied MLEs at two different concentrations (MLE 1 = 1:15 v/v and MLE 2 = 1:30 v/v) twice at 25 and 35 days after seed sowing (50 ml per plant) after the establishment of drought stress. Results revealed that Pa + MLE 2 significantly increased fresh weight (FW), dry weight (DW), lengths of roots and shoot and photosynthetic contents of wheat. A significant enhancement in total soluble sugars, total soluble proteins, calcium, potassium, phosphate, and nitrate contents validated the efficacious effect of Pa + MLE 2 over control-treated plants. Significant decrease in sodium, proline, glycine betaine, electrolyte leakage, malondialdehyde, hydrogen peroxide, superoxide dismutase (SOD), and peroxide (POD) concentrations in wheat cultivated under drought stress conditions also represents the imperative role of Pa + MLE 2 over control. In conclusion, Pa + MLE 2 can alleviate nutritional stress and drought effects in wheat. More research in this field is required to proclaim Pa + MLE 2 as the most effective amendment against drought stress in distinct agroecological zones, different soil types, and contrasting wheat cultivars worldwide.Peer reviewe
Renormalisation and fixed points in Hilbert Space
The energies of low-lying bound states of a microscopic quantum many-body
system of particles can be worked out in a reduced Hilbert space. We present
here and test a specific non-perturbative truncation procedure. We also show
that real exceptional points which may be present in the spectrum can be
identified as fixed points of coupling constants in the truncation procedure.Comment: 4 pages, 1 tabl
Mixing of the CP Even and the CP Odd Higgs Bosons and the EDM Constraints
The mixing among the CP even and the CP odd neutral Higgs bosons of MSSM by
one loop induced effects in the presence of CP phases is investigated using
three different mechanisms to satisfy the EDM constraints, i.e., a fine tuning
of phases, a heavy sparticle spectrum, and the cancellation mechanism. It is
shown that if a mixing effect among the CP even and the CP odd Higgs bosons is
observed experimentally, then it is only the cancellation mechanism that can
survive under the naturalness constraint.Comment: 14 pages, Latex and 4figures. A new paragraph is added and few more
references. One figure is modified. To appear in Phys. Rev.
Effects of Large CP violating phases on g_{\m}-2 in MSSM
Effects of CP violation on the supersymmetric electro-weak correction to the
anomalous magnetic moment of the muon are investigated with the most general
allowed set of CP violating phases in MSSM. The analysis includes contributions
from the chargino and the neutralino exchanges to the muon anomaly. The
supersymmetric contributions depend only on specific combinations of CP phases.
The independent set of such phases is classified. We analyse the effects of the
phases under the EDM constraints and show that large CP violating phases can
drastically affect the magnitude of the supersymmetric electro-weak
contribution to and may even affect its overall sign.Comment: 26 pages Latex file including 4 figure
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