380 research outputs found
HIGH PRICE VOLATILITY AND SPILLOVER EFFECTS IN ENERGY MARKETS
Replaced with revised version of paper 07/22/11.Asymmetric shocks, energy markets, oil, spillover effects, volatility, Marketing, Resource /Energy Economics and Policy, GARCH,
Design of a deep learning based nonlinear aerodynamic surrogate model for UAVs
In this paper, we present a deep learning based surrogate model to determine non-linear aerodynamic characteristics of UAVs. The main advantage of this model is that it can predict the aerodynamic properties of the configurations very quickly by using only geometric configuration parameters without the need for any special input data or pre-process phase. This provides a crucial and explicit design and synthesis tool for mini and small UAVs. To achieve this goal, a large data set, which includes thousands of wing-tail configurations geometry parameters and performance coefficients, was generated using the previously developed and computationally very efficient non-linear lifting line method. This data is used for training the artificial neural network model. The preliminary results show that the neural network model has generalization capability. The aerodynamic model predictions show almost 1-1 coincidence with the numerical data even for configurations with different 2D profiles that are not used in model training. Specifically, the results of test cases are found to capture both the linear and non-linear region of the lift curves, by predicting the maximum lift coefficient, the stall angle of attack, and the characteristics of post-stall region correctly. Similarly, total drag and pitching moment coefficients are predicted successfully. The developed methodology provides the basis for bidirectional design optimization and offers insight for an inverse tool that can calculate geometry parameters for a given design condition
Spatio-temporal patterns of recent and future climate extremes in the eastern Mediterranean and Middle East region
Recent and future changes in temperature and precipitation climate extremes
are estimated using the Hadley Centre PRECIS ("Providing REgional Climates
for Impacts Studies") climate model for the eastern Mediterranean and Middle
East region. The area of interest is considered vulnerable to extreme
climate events as there is evidence for a temperature rise while
precipitation tends to decline, suggesting likely effects on vital
socioeconomic sectors in the region. Observations have been obtained for the
recent period (1961â1990) and used to evaluate the model output. The spatial
distribution of recent temporal trends in temperature indicates strong
increasing in minimum temperature over the eastern Balkan Peninsula, Turkey
and the Arabian Peninsula. The rate of warming reaches
0.4â0.5 °C decade<sup>â1</sup> in a large part of the domain, while
warming is expected to be strongest in
summer (0.6â0.7 °C decade<sup>â1</sup>) in the eastern Balkans and western Turkey. The trends in
annual and summer maximum temperature are estimated at approximately 0.5 and
0.6 °C decade<sup>â1</sup> respectively. Recent estimates do not indicate
statistically significant trends in precipitation except for individual
sub-regions. Results indicate a future warming trend for the study area over
the last 30 years of the 21st century. Trends are estimated to be positive
and statistically significant in nearly the entire region. The annual trend
patterns for both minimum and maximum temperature show warming rates of
approximately 0.4â0.6 °C decade<sup>â1</sup>, with pronounced warming over the Middle
Eastern countries. Summer temperatures reveal a gradual warming
(0.5â0.9 °C decade<sup>â1</sup>) over much of the region. The model projects drying
trends by 5â30% in annual precipitation towards the end of the 21st
century, with the number of wet days decreasing at the rate of 10â30 days year<sup>â1</sup>,
while heavy precipitation is likely to decrease in the
high-elevation areas by 15 days year<sup>â1</sup>
Stress and depression among infertile couples: A cross-sectional study from a government fertility clinic
Background: Infertility is usually associated with long-term stress, which can manifest as anxiety and depressive symptoms. The goal of this study is to look into the emotional well-being of couples dealing with infertility challenges, as well as to look into the causes of anxiety and despair in these couples. Methods: The research was conducted in a government clinic set up at New Delhi, India with the participation of two hundred couples (400 participants), who were attending there for treatment purposes. The Fertility Problem Inventory (FPI) and the Hamilton Depression Score (HAM-D) were utilized to develop the questionnaire. We also interviewed our subjects to find out more about their sociodemographic and fertility-related characteristics. To evaluate our hypotheses, we used independent-samples t-tests (M SD) and the chi-square test. The objective of the study: The study\u27s goal was to assess the stress and sadness experienced by infertile couples who visited government infertility clinics, as well as to determine the independent variables that may have been associated with infertility. These characteristics included age, sex, educational qualification, profession, infertility period, and type of family. Results: Infertile women were younger (48% were in 26 to 30 years), while 40% of men were 31-35 years old. However, females experienced a much lower level of psychological well-being. Anxiety and depression in infertile couples were linked with age, marriage duration, social issues, sexual issues, and marital relationship tension. Financial stress was also associated with trait anxiety. Our method could explain 58 percent of the variance in depressive symptoms and 62 percent of the variance in anxiety-related symptoms. Conclusions: Symptoms of depression and anxiety in infertile couples were present prominently. It caused an impact on marital & sexual relationships. It is essential to encourage the monitoring of these markers as well as the treatment of underlying stress through suitable psychological therapies
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Effect of Demineralized Bone Matrix, Bone Marrow Mesenchymal Stromal Cells, and Platelet-Rich Plasma on Bone Tunnel Healing After Anterior Cruciate Ligament Reconstruction: A Comparative Micro-Computed Tomography Study in a Tendon Allograft Sheep Model
Background:
The effect of demineralized bone matrix (DBM), bone marrowâderived mesenchymal stromal cells (BMSCs), and platelet-rich plasma (PRP) on bone tunnel healing in anterior cruciate ligament reconstruction (ACLR) has not been comparatively assessed.
Hypothesis:
These orthobiologics would reduce tunnel widening, and the effects on tunnel diameter would be correlated with tunnel wall sclerosis.
Study Design:
Controlled laboratory study.
Methods:
A total of 20 sheep underwent unilateral ACLR using tendon allograft and outside-in interference screw fixation. The animals were randomized into 4 groups (n = 5 per group): Group 1 received 4mL of DBM paste, group 2 received 10 million BMSCs in fibrin sealant, group 3 received 12 mL of activated leukocyte-poor platelet-rich plasma, and group 4 (control) received no treatment. The sheep were euthanized after 12 weeks, and micro-computed tomography scans were performed. The femoral and tibial tunnels were divided into thirds (aperture, midportion, and exit), and the trabecular bone structure, bone mineral density (BMD), and tunnel diameter were measured. Tunnel sclerosis was defined by a higher bone volume in a 250-”m volume of interest compared with a 4-mm volume of interest surrounding the tunnel.
Results:
Compared with the controls, the DBM group had a significantly higher bone volume fraction (bone volume/total volume [BV/TV]) (52.7% vs 31.8%; P = .020) and BMD (0.55 vs 0.47 g/cm3; P = .008) at the femoral aperture and significantly higher BV/TV at femoral midportion (44.2% vs 32.9%; P = .038). There were no significant differences between the PRP and BMSC groups versus controls in terms of trabecular bone analysis or BMD. In the controls, widening at the femoral tunnel aperture was significantly greater than at the midportion (46.7 vs 41.7 mm2; P = .034). Sclerosis of the tunnel was common and most often seen at the femoral aperture. In the midportion of the femoral tunnel, BV/TV (r = 0.52; P = .019) and trabecular number (r S = 0.50; P = .024) were positively correlated with tunnel widening.
Conclusion:
Only DBM led to a significant increase in bone volume, which was seen in the femoral tunnel aperture and midportion. No treatment significantly reduced bone tunnel widening. Tunnel sclerosis in the femoral tunnel midportion was correlated significantly with tunnel widening
Prognostic comparison of tissue Doppler indices of diastolic dysfunction and cardiac biomarkers in septic shock
{\phi}^4 Solitary Waves in a Parabolic Potential: Existence, Stability, and Collisional Dynamics
We explore a {\phi}^4 model with an added external parabolic potential term.
This term dramatically alters the spectral properties of the system. We
identify single and multiple kink solutions and examine their stability
features; importantly, all of the stationary structures turn out to be
unstable. We complement these with a dynamical study of the evolution of a
single kink in the trap, as well as of the scattering of kink and anti-kink
solutions of the model. We see that some of the key characteristics of
kink-antikink collisions, such as the critical velocity and the multi-bounce
windows, are sensitively dependent on the trap strength parameter, as well as
the initial displacement of the kink and antikink
A PMT-Block test bench
The front-end electronics of the ATLAS hadronic calorimeter (Tile Cal) is
housed in a unit, called {\it PMT-Block}. The PMT-Block is a compact instrument
comprising a light mixer, a PMT together with its divider and a {\it 3-in-1}
card, which provides shaping, amplification and integration for the signals.
This instrument needs to be qualified before being assembled on the detector. A
PMT-Block test bench has been developed for this purpose. This test bench is a
system which allows fast, albeit accurate enough, measurements of the main
properties of a complete PMT-Block. The system, both hardware and software, and
the protocol used for the PMT-Blocks characterisation are described in detail
in this report. The results obtained in the test of about 10000 PMT-Blocks
needed for the instrumentation of the ATLAS (LHC-CERN) hadronic Tile
Calorimeter are also reported.Comment: 23 pages, 10 figure
Ancient DNA extraction and amplification of human bone samples from the area of Delphi: a pilot case study
The present work is a preliminary effort, an experiment on the extraction of ancient DNA from human remains from a proto-Byzantine context in the area of Delphi. The first results are encouraging; however, the interpretation of such analyses needs to be very careful. DNA and other scientific methods have to take into consideration all historical and socio-economic characteristics of a past society before the proposal, for example, of the existence or migration of specific ethnic groups in an area. The theoretical and methodological thinking of Archaeology in the last decades suggest that all scientific analyses have to evaluate the specific context and the complex nature of human existence before the application of any general-based model
Reply to Comments on Effect of heating rate on kinetic parameters of beta-irradiated Li2B4O7:Cu,Ag,P in TSL measurements
We appreciate the opportunity to respond to comments regarding the paper published by Ege et al (2007 Effect of heating rate on kinetic parameters of beta-irradiated Li2B4O7: Cu, Ag, P in TSL measurements Meas. Sci. Technol. 18 889). We would like to thank the authors for taking the time to tell us about their opinion, but unfortunately we do not agree with them completely. In the article presented by Kumar and Chourasiya some comment is advanced to the analysis of the glow curves measured with different heating rates, presented in our recent study. According to our study, the area under the glow curve decreases with increasing heating rate in TL-temperature plots due to the quenching effects. Contrary to this, Kumar and Chourasiya suggest that this decrease is due to the normalization process. Here we hope to clarify any confusion regarding our published study
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