Inclusive Photoproduction of η\eta Mesons on Nuclei and the in-medium properties of the S11_{11} Resonance

A relativistic non-local model for the inclusive photoproduction of $\eta$ mesons from complex nuclei is introduced. The model is based on the dominance of the S$_{11}$(1535) resonance. We compare the results of our calculations with the available data on inclusive cross sections for the nuclei C, Al and Cu. Assuming the resonance propagates freely in the nuclear medium, we find that the calculated angular distribution and energy dependence of the cross sections reproduce the data in a reasonable fashion. The present non-local model allows the inclusion of density dependent mass and width in the calculations. Including these in the calculations reveals that the presently available data do not show clear preference for the inclusion of such modifications of the properties of the S$_{11}$(1535) in the nuclear medium.Comment: 15 pages, 8 figure

Importance of the direct knockout mechanism in relativistic calculations for (gamma, p) reactions

Results of relativistic calculations of the direct knockout (DKO) mechanism for the photon induced removal of a proton from a target nucleus over a wide range of energies and nuclei are presented. Spectroscopic factors used in the calculations are fixed from consistent analyses of the quasifree electron scattering process (e,e'p). The results indicate that within the uncertainties of the model, the knockout contributions are generally close to the experimental data for missing momenta below approximately 500 MeV/c. This is in disagreement with nonrelativistic analyses which often find that the direct knockout contribution can be quite small compared to the data and that meson exchange corrections can be important. The present study suggests that meson exchange current contributions may not be as large when treated in a relativistic framework. We also point out some difficulties we encountered in analyzing the data for a 12C target at photon energies below 80 MeV.Comment: 25 pages, LaTeX with 8 postscript figure

Long-Range Planning Cost Model for Support of Future Space Missions by the Deep Space Network

A simple model is suggested to do long-range planning cost estimates for Deep Space Network (DSP) support of future space missions. The model estimates total DSN preparation costs and the annual distribution of these costs for long-range budgetary planning. The cost model is based on actual DSN preparation costs from four space missions: Galileo, Voyager (Uranus), Voyager (Neptune), and Magellan. The model was tested against the four projects and gave cost estimates that range from 18 percent above the actual total preparation costs of the projects to 25 percent below. The model was also compared to two other independent projects: Viking and Mariner Jupiter/Saturn (MJS later became Voyager). The model gave cost estimates that range from 2 percent (for Viking) to 10 percent (for MJS) below the actual total preparation costs of these missions

Relativistic calculations for photonuclear reactions; 2, nonrelativistic reductions and nuclear medium effects

The relativistic amplitude for the direct knock-out contribution to \left( \gamma, p \right) reactions on nuclei is reduced to a nonrelativistic form using an effective Pauli reduction scheme. The reduction is carried out to second order in the inverse nucleon mass. It is found that the interaction Hamiltonian appearing in the nonrelativistic amplitude has significant dependence, starting at second order, on the vector and scalar mean nuclear potentials. These strong medium modifications are absent in traditional nonrelativistic calculations. Detailed comparisons show that these modifications are crucial to understanding the differences between relativistic and nonrelativistic models. These differences are also examined through reduction of the relativistic amplitude via the Foldy-Wouthuysen transformation. Similar medium modifications are obtained in this case as well. We discuss the implications of these medium modifications for the consistency of existing nonrelativistic calculations

A Novel Method for Banknote Recognition Using a Combined Histogram of Oriented Gradients and Scale-Invariant Feature Transform

Automated banknote recognition systems are essential for people with visual impairments who face challenges distinguishing between different currency denominations. This study presents a novel method aimed at helping blind people identify banknotes from three different countries (Egypt, Saudi Arabia, and the United States of America) by using a proposed feature detection algorithm. Our proposed system has two main stages: the proposed algorithm uses the Speeded-UP Robust Features (SURF) algorithm for key point detection, as it is fast and robust to variations in geometry and lighting. Then, it extracts features using the scale-invariant feature transform (SIFT) and histogram of oriented gradients (HOG) algorithms, which are scale invariant. This algorithm aims to overcome the limitations of both the SURF and SIFT algorithms and reduce the average response time and computational cost of the SIFT and HOG algorithms. We developed a banknote dataset with 12 classes for three countries. The accuracy of the banknote recognition was 99.2%. The performance of the proposed dataset was compared with that of the global Kaggle Egyptian dataset, resulting in 98.9% accuracy

Nuclear Medium Effects in the Relativistic Treatment of Quasifree Electron Scattering

Non-relativistic reduction of the S-matrix for the quasifree electron scattering process $A\left(~e, e'p~\right)A-1$ is studied in order to understand the source of differences between non-relativistic and relativistic models. We perform an effective Pauli reduction on the relativistic expression for the S-matrix in the one-photon exchange approximation. The reduction is applied to the nucleon current only; the electrons are treated fully relativistically. An expansion of the amplitude results in a power series in the nuclear potentials. The series is found to converge rapidly only if the nuclear potentials are included in the nuclear current operator. The results can be cast in a form which reproduces the non-relativistic amplitudes in the limit that the potentials are removed from the nuclear current operator. Large differences can be found between calculations which do and do not include the nuclear potentials in the different orders of the nuclear current operator. In the high missing momentum region we find that the non-relativistic calculations with potentials included in the nuclear current up to second order give results which are close to those of the fully relativistic calculation. This behavior is an indication of the importance of the medium modifications of the nuclear currents in this model, which are naturally built into the relativistic treatment of the reaction.Comment: Latex, 26 pages including 5 uuencoded postscript figures. accepted for publication in Phys. Rev. C

Impact of Coronavirus Disease-19 Lockdown on Egyptian Children and Adolescents: Dietary Pattern Changes Health Risk

BACKGROUND: Lockdown and school closure related to the coronavirus disease 2019 (COVID-19) have unfavorable effects on children and adolescents. AIM: This study was conducted to survey the changes in dietary pattern and related health factors in Egyptian children and adolescents during the COVID-19 outbreak closure. MATERIALS AND METHODS: Data were collected through a dietary pattern, eating behavior, and physical activity electronic questionnaire conducted through social media sites, targeting parents of children and adolescents after two whole months of lockdown and school closure in Egypt. RESULTS: This study included 765 participants, 31.8% noted increased appetite, 45.6% reported increased sweets and unhealthy food consumption, and 37.6% showed increased frequent snacking between meals. Alongside 53.1% showed increase in late snacks during night after COVID-19 closure. The majority of our participants 82.0% noted associative change in eating behavior with boring and 94.6% revealed increased usage of electronics and screen time. This study showed significant positive correlation between increased appetite and mobile screen time, laptop screen time, and video gaming. Increased sweets and unhealthy food consumption was positively correlated with TV watching and mobile screen time. A significant positive correlation was revealed between uncaring about eating fruits and vegetables and increase screen time for each of mobile, and laptop and remote learning. Furthermore, there was positive correlation between decreased protein serving intake and each of mobile screen time and remote learning. TV watching and laptop screen times showed positively significantly association with frequent snacking between meals. Mobile screen time, TV screen time, and video gaming were positively significantly correlated with late night snacking. CONCLUSIONS: The present study concluded prolonged lockdown leads to changes in eating patterns, related to contributing factors of physical inactivity and prolonged screen time

Evaluating the In vivo Efficacy of Copper-Chitosan Nanocomposition for Treating Vascular Wilt Disease in Date Palm

Date palm, Phoenix dactylifera, as one of the most important fruit crops in Egypt and many other countries, can be affected by many fungal diseases, among which the vascular wilt disease, caused by the fungal pathogen Fusarium oxysporum, is considered the most deteriorating one. This study aims at evaluating the efficiency of Copper-Chitosan Nanopcomposition for treating the vascular wilt disease in date palm. The study relies mainly on beleaguering the disease via the double-role functionality of copper-chitosan nanocomposition, i.e. its potential antifungal effect on the fungal pathogen, besides its capability to enhance the immune responses of the infected plant. In this regard, chitosan nanoparticles were prepared according to the ionic gelation method, whereas copper nanoparticles were prepared according to the chemical reduction method. Physicochemical characterization of both chitosan and copper nanoparticles was performed using dynamic light scattering (DLS), transmission electron microscopy (TEM), fourier transform infrared spectroscopy (FTIR) and x-ray diffraction (XRD). Copper-chitosan nanocomposition could significantly reduce the vascular wilt disease severity; this means that the nanocomposition can be used in the future for developing new nano-fungicides to control such pathogens

Blunt Liver Trauma at Sunnybrook Medical Centre: A 13 Year Experience

Between June 1, 1976 and June 30, 1989 The Regional Trauma Unit at Sunnybrook Medical Centre in Toronto, Ontario, Canada received 3730 patients. Of these 335 (9%) sustained a liver injury, 95% being due to blunt trauma. Open peritoneal lavage was performed on 80% of liver trauma patients (267/335), 99% being true positive