122 research outputs found
" Do Financial Planners Take Financial Crashes In Their Advice: Dynamic Asset Allocation Under Thick Tails And Fast Volatility Updating
Strategic Asset Allocation in Stochastic Environment And Incomplete Markets: Evidence on Horizon And Hedging Effects
A Widely Tunable High-power Continuous-wave Optical Parametric Oscillator (cw-opo) System For Mid-infrared Spectroscopy And Frequency Metrology
Continuous-wave optical parametric oscillators (CW-OPOs) can offer broad tuning with high resolution and high power in the mid-infrared (MIR) and have many important potential applications in precision spectroscopy. The widely tunable cw-OPO system (TOPO) developed by TOPTICA Photonics is capable of covering the wavelength range of 1.45-4.0 m (with a degenerate gap between 2.07-2.19 m) without optics or nonlinear optical crystal exchanges. A computer-controlled automation system has been developed to achieve a broad (up to 300 GHz) mode-hop-free (MHF) tuning range of the idler wavelengths and high output power (1 W). Its narrow linewidth is demonstrated in the direct absorption measurements and the Doppler-free saturated absorption spectroscopy of atmospheric molecules. Furthermore, a much-improved frequency accuracy has been achieved by referencing the OPO to a frequency comb and creating a phase-coherent bridge between the NIR and MIR spectral ranges. Frequency noise from both the OPO cavity and the seed laser is eliminated by (i) beating the OPO signal output against the fundamental of the frequency comb and (ii) beating the seed laser against a 1064 nm comb extension. The TOPO system has been incorporated in the MIR cavity ring-down (CRD) system and the CRD-based two-photon spectroscopy system in our lab
Analytical Estimation of Value at Risk Under Thick Tails and Fast Volatility Updating
Despite its recent advent, value at risk (VaR) became the most widely used technique for measuring future expected risk for both financial and non-financial institutions. VaR, the measure of the worst expected loss over a given horizon at a given confidence level, depends crucially on the distributional aspects of trading revenues. Existing VaR models do not capture adequately some empirical aspects of financial data such as the tail thickness, which is vital in VaR calculations. Tail thickness in financial variables results basically from stochastic volatility and event risk (jumps). Those two sources are not totally separated; under event risk, volatility updates faster than under normal market conditions. Generally, tail thickness is associated with hyper volatility updating. Existing VaR literature accounts partially for tail thickness either by including stochastic volatility or by including jump diffusion, but not both. Additionally, this literature does not account for fast updating of volatility associated with tail thickness. This dissertation fills the gap by developing analytical VaR models account for the total (maximum) tail thickness and the associated fast volatility updating. Those aspects are achieved by assuming that trading revenues are evolving according to a mixed non-affine stochastic volatility-jump diffusion process. The mixture of stochastic volatility and jumps diffusion accounts for the maximum tail thickness, whereas the nonaffine structure of stochastic volatility captures the fast volatility updating. The non-affine structure assumes that volatility dynamics are non-linearly related to the square root of current volatility rather than the traditional linear (affine) relationship. VaR estimates are obtained by deriving the conditional characteristic function, and then inverting it numerically via the Fourier Inversion technique to infer the cumulative distribution function. The application of the developed VaR models on a sample that contains six U.S banks during the period 1995-2002 shows that VaR models based on the non-affine stochastic volatility and jump diffusion process produce more reliable VaR estimates compared with the banks\u27 own VaR models. The developed VaR models could significantly predict the losses that those banks incurred during the Russian crisis and the near collapse of the LTCM in 1998 when the banks\u27 VaR models fail
Laser spectroscopy investigations on molecular and free radicals dynamics.
Studying molecular dynamics and chemical kinetics is important to understand the chemical behavior of renewable energy sources. Laser spectroscopy techniques are powerful tools for the identification and diagnosis of such processes. In this dissertation, using our laser spectroscopy techniques, biofuels and solar energy were targeted as renewable energy sources study. We have studied the ultrafast exciton dynamics for a series of methylammonium lead bromide (CH3NH3PbBr3) nanostructures, nanocrystals (NCs, 0D), nanowires (NWs, 1D), and nanoplatelets (NPs, 2D) as a promising solar energy materials.1-2 Aided by analysis of UVâvisible absorption and photoluminescence spectra, features in the transient absorption (TA) spectra are assigned to different charge carrier processes, time constants of which are determined in fitting the transient kinetics. Immediately after photoexcitation, the charge carrier thermalization process occurs within the instrument response function time and results in a quasi-equilibrium distribution of charge carriers. It is followed by charge carrier cooling on a sub-picosecond time scale. The charge carrier recombination process obeys the rate law of a second-order reaction, which suggests that it occurs mainly via the bimolecular nongeminate recombination process. Dependence of the charge recombination rate constant on the initial charge carrier density has also been investigated in fluence-dependence measurements. The sensitivity of the recombination rate constant to initial charge carrier density is different for the three perovskite nanostructures, signifying the strong impact of quantum confinement on exciton dynamics. Using room-temperature cavity ring-down spectroscopy (CRDS), we obtained the spectra of the AÌ â XÌ electronic transition of tetrahydrofuranyl peroxy (THFOOâą) and tetrahydropyranyl peroxy (THPOOâą) radicals.3-4 The peroxy radicals were produced by Cl-initiated oxidation of tetrahydrofuran and tetrahydropyran. Quantum chemical calculations of the lowest-energy conformers of all regioisomers of these two peroxy radicals have been carried out to aid the spectral simulation. Conformational identification and vibrational assignment were achieved by comparing the experimentally obtained spectra to the simulated ones. The absence of α-THPOOâą absorption peaks in the CRD spectrum is attributed to ring-opening due to its weak CαâČO bond
NCDR and Women in Jordan
High levels of gender inequality exist within Jordanâinequalities that affect the workforce. In a nation like Jordan, where women have minimal political participation and only 26 percent of women are active economically, it is difficult for women to be incorporated into the workforce. Fewer women are employed outside of the home when compared to men, with only 9 percent of Jordanian women above the age of 15 working outside their homes. Among females, unemployment rates are double those for males; further, high percentages of women are discouraged from seeking employment outside of the home. Women who are employed are typically compensated with much lower wages than men in the same fields. The roots of these problems arise from a lack of available employment options that are compatible with the current social roles for women
Biologic and Immunotherapy Developments in Advanced Hepatocellular Carcinoma
Hepatocellular carcinoma (HCC) is the most common primary cancer of the liver, and the second leading cause of cancer-related mortality worldwide with a very poor 5-year survival. Treatment for HCC includes surgery, liver-directed therapies and systemic therapies. Until 2008, no effective systemic therapy was available for advanced HCC. Sorafenib is the first drug to show improvement in overall survival among patients with advanced HCC in comparison to placebo, and it is approved by U.S. Food and Drug Administration (FDA) as a first-line treatment of advanced HCC. After sorafenib approval, several targeted and immune therapies were tested and showed efficacy in advanced HCC. Lenvatinib has been shown to be non-inferior to sorafenib as first-line treatment. Both nivolumab and regorafenib showed improvement in overall survival among patients with advanced HCC as a second line treatment after progression on sorafenib, and both are FDA approved for this indication. There is a limited role for cytotoxic agents in the treatment of advanced HCC
Arabic Teachersâ Evaluation Degree of their Reading Teaching Strategies and Practices
The present study measured the Arabic teachersâ evaluation degree of their own reading teaching strategies and practices to reveal any statistically significant differences in terms of two teacher-related variables: educational qualification and years of experience. In order to achieve the objectives of the study, the researcher developed a questionnaire of 33 paragraphs distributed in three phases: pre-reading, during-reading, and post-reading. The study sample consisted of 302 female and male Arabic teachers who were selected following the simple random approach out of the total study population (730 female and male teachers). The results of the study revealed that the Arabic teachersâ evaluation degree of their reading teaching strategies was high; however, no statistically significant differences were found in terms of teachersâ educational qualification and or their years of experience. The results are pedagogically analyzed, and a number of recommendations were set forth for teaching reading and future directions of research. Keywords: Arabic language Teachers, Reading Comprehension, Reading Teaching Strategies. The present study measured the Arabic teachersâ evaluation degree of their own reading teaching strategies and practices to reveal any statistically significant differences in terms of two teacher-related variables: educational qualification and years of experience. In order to achieve the objectives of the study, the researcher developed a questionnaire of 33 paragraphs distributed in three phases: pre-reading, during-reading, and post-reading. The study sample consisted of 302 female and male Arabic teachers who were selected following the simple random approach out of the total study population (730 female and male teachers). The results of the study revealed that the Arabic teachersâ evaluation degree of their reading teaching strategies was high; however, no statistically significant differences were found in terms of teachersâ educational qualification and or their years of experience. The results are pedagogically analyzed, and a number of recommendations were set forth for teaching reading and future directions of research
Performance assessment of commercial principles in water services provision
As a water scarce country, Jordan started initiatives to reform its water sector to meet the objective of bridging the gap between increasing demands and diminishing renewable water supply, besides implementing technical solutions. Commercialization, as alternative to privatization in its conventional notion, was adopted as a strategy to extend partnership with the private sector and to establish new corporatized water service companies wholly owned by the Government and operated under commercial principles. This paper assesses the utilization of commercial and market principles in managing water services provision, it assesses Amman water utility performances under the management of Jordan water Company (Miyahuna) Corporate and the Management Contractor (LEMA). The assessment covered the period from 1999 through 2013, with 1999 as a base year. It was based on the International Water Association recommended performance indicators and on the customized ones, as used by the Ministry of Water and Irrigation. Financial sustainability Criteria variations and its trends has been analysed, discussed and historically tracked for possible indications and causes. Miyahuna performance was compared to international and regional performance standards using data available on the International Benchmarking Network for Water and Sanitation Utilities database. This inter-utility comparison may trigger enhancement as the water sector direct completion is limited. The paper concludes that application of the corporatize model for the Amman utility was successful. Miyahuna performance in the long term reveals positive trends in most of the evaluated criteria
Improvement in Adherence to Surgical Antimicrobial Prophylaxis Guidelines after Implementation of a Multidisciplinary Quality Improvement Project
Objectives: This study aimed to show the impact of a multidisciplinary quality improvement project on adherence to antimicrobial prophylaxis guidelines in oncological surgery. Methods: This pre- and post-intervention prospective observational study was carried out at the King Hussein Cancer Centre (KHCC) in Amman, Jordan, between August 2009 and February 2012. The quality improvement project consisted of revising the institutional guidelines for surgical antimicrobial prophylaxis, assigning a clinical pharmacist to the surgical department, establishing an operating room satellite pharmacy and providing education regarding the appropriate utilisation of antibiotics. The medical records of adult cancer patients who underwent surgery were evaluated one month before and one month after the project was implemented to assess adherence to the guidelines with regards to antibiotics prescribed, drug doses and timing and treatment duration. Results: A total of 70 patients were evaluated before and 97 patients were evaluated after the intervention, of which 57 (81.4%) and 95 (97.9%) patients received antibiotics, respectively. In comparing the pre- and post-intervention groups, an improvement was observed in the proportion of patients who received antibiotics at the appropriate time (n = 12 versus n = 79; 21.1% versus 83.2%; P <0.01), for the appropriate duration of time (n = 22 versus n = 94; 38.6% versus 99.0%; P <0.01) and in the appropriate dose (n = 9 versus n = 87; 56.3% versus 98.9%; P <0.01). Conclusion: Adherence to the antimicrobial prophylaxis guidelines at KHCC improved significantly after the implementation of a quality improvement project
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