Gamma ray shielding is essential to ensure the safety of personnel and equipment in facilities and environments where radiation exists.The Monte Carlo technique is vital for analyzing the gamma-ray shielding capabilit...Gamma ray shielding is essential to ensure the safety of personnel and equipment in facilities and environments where radiation exists.The Monte Carlo technique is vital for analyzing the gamma-ray shielding capabilities of materials.In this study,a simple Monte Carlo code,EJUSTCO,is developed to cd simulate gamma radiation transport in shielding materials for academic purposes.The code considers the photoelectric effect,Compton(incoherent)scattering,pair production,and photon annihilation as the dominant interaction mechanisms in the gamma radiation shielding problem.Variance reduction techniques,such as the Russian roulette,survival weighting,and exponential transformation,are incorporated into the code to improve computational efficiency.Predicting the exponential transformation parameter typically requires trial and error as well as expertise.Herein,a deep learning neural network is proposed as a viable method for predicting this parameter for the first time.The model achieves an MSE of 0.00076752 and an R-value of 0.99998.The exposure buildup factors and radiation dose rates due to the passage of gamma radiation with different source energies and varying thicknesses of lead,water,iron,concrete,and aluminum in single-,double-,and triple-layer material systems are validated by comparing the results with those of MCNP,ESG,ANS-6.4.3,MCBLD,MONTEREY MARK(M),PENELOPE,and experiments.Average errors of 5.6%,2.75%,and 10%are achieved for the exposure buildup factor in single-,double-,and triple-layer materials,respectively.A significant parameter that is not considered in similar studies is the gamma ray albedo.In the EJUSTCO code,the total number and energy albedos have been computed.The results are compared with those of MCNP,FOTELP,and PENELOPE.In general,the EJUSTCO-developed code can be employed to assess the performance of radiation shielding materials because the validation results are consistent with theoretical,experimental,and literary results.展开更多
Gamma-ray polarimetry is a new and prospective tool for studying extremely high-energy celestial objects and is of great significance for the field of astrophysics.With the rapid development of microsatellite technolo...Gamma-ray polarimetry is a new and prospective tool for studying extremely high-energy celestial objects and is of great significance for the field of astrophysics.With the rapid development of microsatellite technology,the advantages of space exploration have become increasingly apparent.Therefore,we simulated a soft-gamma-ray polarimeter for a microsatellite based on the Compton scattering principle.We performed detailed Monte Carlo simulations using monoenergetic gamma-ray linear-polarization sources and Crab-like sources in the energy range of 0.1-10 MeV considering the orbital background.The polarimeter exhibited excellent polarization detection performance.The modulation factor was 0.80±0.01,and the polarization angles were accurate within an error of 0.2°at 200 keV for on-axis incidence.For the Crab-like sources for on-axis incidence,the polarization degrees were consistent with the set values within the error tolerance,the modulation factor was 0.76±0.01,and the minimum detectable polarization reached 2.4%at 3σfor an observation time of10^(6) s.Additionally,the polarimeter exhibited recoil electron tracking,imaging,and powerful background suppression in a large field of view(FoV;∼2πsr).The proposed polarimeter meets the requirements of a space soft-gamma-ray polarization detector and has promising research prospects.展开更多
We show that recently multi-messenger astronomy has provided compelling evidence that the bulk of high energy cosmic rays (CRs) are produced by highly relativistic narrow jets of plasmoids launched in core collapse of...We show that recently multi-messenger astronomy has provided compelling evidence that the bulk of high energy cosmic rays (CRs) are produced by highly relativistic narrow jets of plasmoids launched in core collapse of stripped-envelope massive stars to neutron stars and stellar mass black holes. Such events produce also a visible GRB if the jet happens to point in our direction. This has been long advocated by the cannon ball (CB) model of high energy CRs and GRBs, but the evidence has been provided only recently by what were widely believed to be unrelated discoveries. They include the very recent discovery of a knee around TeV in the energy spectrum of high energy CR electrons, the peak photon energy in the “brightest of all time” GRB221009A, and the failure of IceCube to detect high energy neutrinos from GRBs, including GRB221009A. They were all predicted by the cannonball (CB) model of high energy CRs and GRBs long before they were discovered in observations, despite a negligible probability to occur by chance.展开更多
BACKGROUND The traditional Gamma3 nail is a mainstream treatment for femoral intertrochanteric fractures.Literature reports that the Gamma3U-blade system can increase the stability of the Gamma3 nail and reduce compli...BACKGROUND The traditional Gamma3 nail is a mainstream treatment for femoral intertrochanteric fractures.Literature reports that the Gamma3U-blade system can increase the stability of the Gamma3 nail and reduce complication incidence.However,comparative studies between the Gamma3U-blade and Gamma3 systems are limited;hence,this meta-analysis was performed to explore the clinical efficacy of these two surgical methods.AIM To investigate the clinical efficacy of Gamma3 and Gamma3 U-blade for intertrochanteric fractures.METHODS A computerized search for Chinese and English literature published from 2010 to 2022 was conducted in PubMed,Cochrane,CNKI,Wanfang,and VIP databases.The search keywords were gamma 3,gamma 3 U blade,and intertrochanteric fracture.Additionally,literature tracking was performed on the references of published literature.The data were analyzed using Revman 5.3 software.Two individuals checked the inputs for accuracy.Continuous variables were described using mean difference and standard deviation,and outcome effect sizes were expressed using ratio OR and 95%confidence interval(CI).High heterogeneity was considered at(P<0.05,I2>50%),moderate heterogeneity at I2 from 25%to 50%,and low heterogeneity at(P≥0.05,I2<50%).RESULTS Following a comprehensive literature search,review,and analysis,six articles were selected for inclusion in this study.This selection comprised five articles in English and one in Chinese,with publication years spanning from 2016 to 2022.The study with the largest sample size,conducted by Seungbae in 2021,included a total of 304 cases.Statistical analysis:A total of 1063 patients were included in this meta-analysis.The main outcome indicators were:Surgical time:The Gamma3U blade system had a longer surgical time compared to Gamma3 nails(P=0.006,I2=76%).Tip-apex distance:No statistical significance or heterogeneity was observed(P=0.65,I2=0%).Harris Hip score:No statistical significance was found,and low heterogeneity was detected(P=0.26,I2=22%).Union time:No statistical significance was found,and high heterogeneity was detected(P=0.05,I2=75%).CONCLUSION Our study indicated that the Gamma3 system reduces operative time compared to the Gamma3 U-blade system in treating intertrochanteric fractures.Both surgical methods proved to be safe and effective for this patient group.These findings may offer valuable insights and guidance for future surgical protocols in hip fracture patients.展开更多
Several densities or probability laws of continuous random variables derive from the Euler Gamma function. These laws form the basis of sampling theory, namely hypothesis testing and estimation. Namely the gamma, beta...Several densities or probability laws of continuous random variables derive from the Euler Gamma function. These laws form the basis of sampling theory, namely hypothesis testing and estimation. Namely the gamma, beta, and Student law, through the chi-square law and the normal law are all distributions resulting from applications of Euleur functions.展开更多
The Giant Radio Array for Neutrino Detection(GRAND)is a proposed large-scale observatory designed to detect cosmic rays,gamma-rays,and neutrinos with energies exceeding 100 Pe V.The GRANDProto300 experiment is propose...The Giant Radio Array for Neutrino Detection(GRAND)is a proposed large-scale observatory designed to detect cosmic rays,gamma-rays,and neutrinos with energies exceeding 100 Pe V.The GRANDProto300 experiment is proposed as the early stage of the GRAND project,consisting of a hybrid array of radio antennas and scintillator detectors.The latter,as a mature and traditional detector,is used to cross-check the nature of the candidate events selected from radio observations.In this study,we developed a simulation software called G4GRANDProto300,based on the Geant4 software package,to optimize the spacing of the scintillator detector array and to investigate its effective area.The analysis was conducted at various zenith angles under different detector spacings,including 300,500,600,700,and 900 m.Our results indicate that,for large zenith angles used to search for cosmic-ray in the GRAND project,the optimized effective area is with a detector spacing of 500 m.The G4GRANDProto300 software that we developed could be used to further optimize the layout of the particle detector array in future work.展开更多
Background: This study aimed to evaluate the diagnostic value of interferon-γ release assay (IGRA), a sensitive microbiological diagnostic method, in children and adolescents with suspected tuberculosis in a country ...Background: This study aimed to evaluate the diagnostic value of interferon-γ release assay (IGRA), a sensitive microbiological diagnostic method, in children and adolescents with suspected tuberculosis in a country with a high burden of tuberculosis. Method: This study included 581 children and adolescents aged 4 - 19 years who were suspected of having tuberculosis, were latently infected with Mycobacterium tuberculosis, and had received at least one dose of BCG vaccine between April 17, 2019, and February 24, 2021. The study evaluated the TST results of 106 patients who had a positive Quantiferon test and were suspected of having tuberculosis. Results: The study included 581 patients aged between 4 and 19 years. Of these, 106 patients tested positive for the Quantiferon test, while 19 were indeterminate and 456 were negative. The Quantiferon test positivity rate was 18.24%. Among the 106 QFT-Plus-positive cases, 23 patients also tested positive for TST. The difference in distribution was found to be statistically significant. Conclusion: The QFT-Plus test is considered an alternative to TST and other microbiological diagnostic methods for early tuberculosis diagnosis, particularly in children and adolescents.展开更多
According to a recent calculation, 10<sup>58</sup> erg of radiant energy was released by Sgr A*, when it formed the Fermi bubbles. Here, it is argued that this explosion constituted a long gamma-ray burst. .
Lorentz Invariance is a foundational principle in modern physics, but some recent quantum gravity theories have hinted that it may be violated at extremely high energies. Gamma-ray bursts (GRBs) provide a promising to...Lorentz Invariance is a foundational principle in modern physics, but some recent quantum gravity theories have hinted that it may be violated at extremely high energies. Gamma-ray bursts (GRBs) provide a promising tool for checking and constraining any deviations from Lorentz Invariance due to their huge energies and cosmological distances. Gamma-ray bursts, which are the most intense and powerful explosions in the universe, are traditionally divided into long bursts whose observed duration exceeds 2 s, and short bursts whose observed duration is less than 2 s. In this study, we employ a recent sample of 46 short GRBs to check for any deviation from Lorentz Invariance. We analyze the spectral lag of the bursts in our data sample and check for any redshift dependence in the GRB rest frame, which would indicate a violation of Lorentz Invariance. Our results are consistent, to within 1σ, with no deviation from Lorentz Invariance.展开更多
为了研究不同码型的卷积码在水下湍流信道中的误码率(BER)性能,采用接受-拒绝采样模拟湍流信道乘性干扰,并选择二进制相移键控(BPSK)调制方式,建立Gamma-Gamma湍流信道通信系统仿真模型。仿真结果表明:在不同强度的湍流信道中,采用卷积...为了研究不同码型的卷积码在水下湍流信道中的误码率(BER)性能,采用接受-拒绝采样模拟湍流信道乘性干扰,并选择二进制相移键控(BPSK)调制方式,建立Gamma-Gamma湍流信道通信系统仿真模型。仿真结果表明:在不同强度的湍流信道中,采用卷积码编码均能提升系统的BER性能;卷积码的码率越小,系统BER性能提升越显著;随着信噪比(SNR)增大,记忆深度越长,系统BER下降速度越快;采用软译码比采用硬译码时增益至少提升2.82 d B;卷积码的解码不仅受当前信息的影响,还与之前的码元信息有关。展开更多
Background and Aims While chest X-ray (CXR) has been a conventional tool in intensive care units (ICUs) to identify lung pathologies, computed tomography (CT) scan remains the gold standard. Use of lung ultrasound (LU...Background and Aims While chest X-ray (CXR) has been a conventional tool in intensive care units (ICUs) to identify lung pathologies, computed tomography (CT) scan remains the gold standard. Use of lung ultrasound (LUS) in resource-rich ICUs is still under investigation. The present study compares the utility of LUS to that of CXR in identifying pulmonary edema and pleural effusion in ICU patients. In addition, consolidation and pneumothorax were analyzed as secondary outcome measures. Material and Methods This is a prospective, single centric, observational study. Patients admitted in ICU were examined for lung pathologies, using LUS by a trained intensivist;and CXR done within 4 hours of each other. The final diagnosis was ascertained by an independent senior radiologist, based on the complete medical chart including clinical findings and the results of thoracic CT, if available. The results were compared and analyzed. Results Sensitivity, specificity and diagnostic accuracy of LUS was 95%, 94.4%, 94.67% for pleural effusion;and 98.33%, 97.78%, 98.00% for pulmonary edema respectively. Corresponding values with CXR were 48.33%, 76.67%, 65.33% for pleural effusion;and 36.67%, 82.22% and 64.00% for pulmonary edema respectively. Sensitivity, specificity and diagnostic accuracy of LUS was 91.30%, 96.85%, 96.00% for consolidation;and 100.00%, 79.02%, 80.00% for pneumothorax respectively. Corresponding values with CXR were 60.87%, 81.10%, 78.00% for consolidation;and 71.3%, 97.20%, 96.00% for pneumothorax respectively. Conclusion LUS has better diagnostic accuracy in diagnosis of pleural effusion and pulmonary edema when compared with CXR and is thus recommended as an effective alternative for diagnosis of these conditions in acute care settings. Our study recommends that a thoracic CT scan can be avoided in most of such cases.展开更多
Long-term levodopa administration can lead to the development of levodopa-induced dyskinesia.Gamma oscillations are a widely recognized hallmark of abnormal neural electrical activity in levodopa-induced dyskinesia.Cu...Long-term levodopa administration can lead to the development of levodopa-induced dyskinesia.Gamma oscillations are a widely recognized hallmark of abnormal neural electrical activity in levodopa-induced dyskinesia.Currently,studies have reported increased oscillation power in cases of levodopa-induced dyskinesia.However,little is known about how the other electrophysiological parameters of gamma oscillations are altered in levodopa-induced dyskinesia.Furthermore,the role of the dopamine D3 receptor,which is implicated in levodopa-induced dyskinesia,in movement disorder-related changes in neural oscillations is unclear.We found that the cortico-striatal functional connectivity of beta oscillations was enhanced in a model of Parkinson’s disease.Furthermore,levodopa application enhanced cortical gamma oscillations in cortico-striatal projections and cortical gamma aperiodic components,as well as bidirectional primary motor cortex(M1)↔dorsolateral striatum gamma flow.Administration of PD128907(a selective dopamine D3 receptor agonist)induced dyskinesia and excessive gamma oscillations with a bidirectional M1↔dorsolateral striatum flow.However,administration of PG01037(a selective dopamine D3 receptor antagonist)attenuated dyskinesia,suppressed gamma oscillations and cortical gamma aperiodic components,and decreased gamma causality in the M1→dorsolateral striatum direction.These findings suggest that the dopamine D3 receptor plays a role in dyskinesia-related oscillatory activity,and that it has potential as a therapeutic target for levodopa-induced dyskinesia.展开更多
We present a pilot study of time delays Δt in four GRB Radio Afterglow emissions, i.e., delays in the arrival times of radio waves of different frequencies emanating from eight GRB Radio Afterglows. Unlike in most st...We present a pilot study of time delays Δt in four GRB Radio Afterglow emissions, i.e., delays in the arrival times of radio waves of different frequencies emanating from eight GRB Radio Afterglows. Unlike in most studies on this phenomenon, we do not assume that this time delay is due to the Photon being endowed with a non-zero mass, but that this may very well be due to the interstellar space being a cold rarefied cosmic plasma, which medium’s Electrons interact with the electric component of the Photon, thus generating tiny currents that lead to dispersion, hence, a frequency (v) dependent speed of Light where this speed scales off as v<sup>-</sup><sup>1</sup>. The said interaction is such that, lower frequency Photons will propagate at lower speeds than higher frequency Photons thus leading to the observed time delays in the arrivals times of Photons of different frequencies. In reasonable accord with the proposed model, we find that for four of these GRB afterglows, there is a strong unsolicited correlation between the observed time delays and the frequency. If this model can be corroborated by a large enough data set, there is hope that this same model might lead to a better understanding of the observed time delays in GRBs.展开更多
Ray tracing is a computer graphics method that renders images realistically. As the name suggests, this technique primarily traces the path of light rays interacting with objects in a scene [1], permitting the calcula...Ray tracing is a computer graphics method that renders images realistically. As the name suggests, this technique primarily traces the path of light rays interacting with objects in a scene [1], permitting the calculation of lighting and reflecting impact [2]. As ray tracing is a time-consuming process, the need for parallelization to solve this problem arises. One downside of this solution is the existence of race conditions. In this work, we explore and experiment with a different, well-known solution for this race condition. Starting with the introduction and the background section, a brief overview of the topic is followed by a detailed part of how the race conditions may occur in the case of the ray tracing algorithm. Continuing with the methods and results section, we have used OpenMP to parallelize the Ray tracing algorithm with the different compiler directives critical, atomic, and first-private. Hence, it concluded that both critical and atomic are not efficient solutions to produce a good-quality picture, but first-private succeeded in producing a high-quality picture.展开更多
Two new solutions of the homogeneous diffusion equation in 1D are derived in the presence of losses and a trigonometric profile for a profile of density. A simulation for the ankle in the energy distribution of cosmic...Two new solutions of the homogeneous diffusion equation in 1D are derived in the presence of losses and a trigonometric profile for a profile of density. A simulation for the ankle in the energy distribution of cosmic rays (CRs) is provided in the framework of the fine tuning of the involved parameters. A theoretical image for the overall diffusion of CRs in galactic coordinates is provided.展开更多
基金Our profound gratitude and appreciation go to the Egyptian and Japanese governments for supporting and financing this research work at the Egypt-Japan University of Science and TechnologyFurther appreciation goes to the Science and Technology Development Fund for the additional financial support(project ID:STDF-33397).
文摘Gamma ray shielding is essential to ensure the safety of personnel and equipment in facilities and environments where radiation exists.The Monte Carlo technique is vital for analyzing the gamma-ray shielding capabilities of materials.In this study,a simple Monte Carlo code,EJUSTCO,is developed to cd simulate gamma radiation transport in shielding materials for academic purposes.The code considers the photoelectric effect,Compton(incoherent)scattering,pair production,and photon annihilation as the dominant interaction mechanisms in the gamma radiation shielding problem.Variance reduction techniques,such as the Russian roulette,survival weighting,and exponential transformation,are incorporated into the code to improve computational efficiency.Predicting the exponential transformation parameter typically requires trial and error as well as expertise.Herein,a deep learning neural network is proposed as a viable method for predicting this parameter for the first time.The model achieves an MSE of 0.00076752 and an R-value of 0.99998.The exposure buildup factors and radiation dose rates due to the passage of gamma radiation with different source energies and varying thicknesses of lead,water,iron,concrete,and aluminum in single-,double-,and triple-layer material systems are validated by comparing the results with those of MCNP,ESG,ANS-6.4.3,MCBLD,MONTEREY MARK(M),PENELOPE,and experiments.Average errors of 5.6%,2.75%,and 10%are achieved for the exposure buildup factor in single-,double-,and triple-layer materials,respectively.A significant parameter that is not considered in similar studies is the gamma ray albedo.In the EJUSTCO code,the total number and energy albedos have been computed.The results are compared with those of MCNP,FOTELP,and PENELOPE.In general,the EJUSTCO-developed code can be employed to assess the performance of radiation shielding materials because the validation results are consistent with theoretical,experimental,and literary results.
基金This work was supported by the National Natural Science Foundation of China(Nos.U2031206,12273086,12133007)the CAS Key Technology Talent Program。
文摘Gamma-ray polarimetry is a new and prospective tool for studying extremely high-energy celestial objects and is of great significance for the field of astrophysics.With the rapid development of microsatellite technology,the advantages of space exploration have become increasingly apparent.Therefore,we simulated a soft-gamma-ray polarimeter for a microsatellite based on the Compton scattering principle.We performed detailed Monte Carlo simulations using monoenergetic gamma-ray linear-polarization sources and Crab-like sources in the energy range of 0.1-10 MeV considering the orbital background.The polarimeter exhibited excellent polarization detection performance.The modulation factor was 0.80±0.01,and the polarization angles were accurate within an error of 0.2°at 200 keV for on-axis incidence.For the Crab-like sources for on-axis incidence,the polarization degrees were consistent with the set values within the error tolerance,the modulation factor was 0.76±0.01,and the minimum detectable polarization reached 2.4%at 3σfor an observation time of10^(6) s.Additionally,the polarimeter exhibited recoil electron tracking,imaging,and powerful background suppression in a large field of view(FoV;∼2πsr).The proposed polarimeter meets the requirements of a space soft-gamma-ray polarization detector and has promising research prospects.
文摘We show that recently multi-messenger astronomy has provided compelling evidence that the bulk of high energy cosmic rays (CRs) are produced by highly relativistic narrow jets of plasmoids launched in core collapse of stripped-envelope massive stars to neutron stars and stellar mass black holes. Such events produce also a visible GRB if the jet happens to point in our direction. This has been long advocated by the cannon ball (CB) model of high energy CRs and GRBs, but the evidence has been provided only recently by what were widely believed to be unrelated discoveries. They include the very recent discovery of a knee around TeV in the energy spectrum of high energy CR electrons, the peak photon energy in the “brightest of all time” GRB221009A, and the failure of IceCube to detect high energy neutrinos from GRBs, including GRB221009A. They were all predicted by the cannonball (CB) model of high energy CRs and GRBs long before they were discovered in observations, despite a negligible probability to occur by chance.
基金Supported by The Clinical Medical Science and Technology Development Fund Project of Jiangsu University,No.JLY2021185.
文摘BACKGROUND The traditional Gamma3 nail is a mainstream treatment for femoral intertrochanteric fractures.Literature reports that the Gamma3U-blade system can increase the stability of the Gamma3 nail and reduce complication incidence.However,comparative studies between the Gamma3U-blade and Gamma3 systems are limited;hence,this meta-analysis was performed to explore the clinical efficacy of these two surgical methods.AIM To investigate the clinical efficacy of Gamma3 and Gamma3 U-blade for intertrochanteric fractures.METHODS A computerized search for Chinese and English literature published from 2010 to 2022 was conducted in PubMed,Cochrane,CNKI,Wanfang,and VIP databases.The search keywords were gamma 3,gamma 3 U blade,and intertrochanteric fracture.Additionally,literature tracking was performed on the references of published literature.The data were analyzed using Revman 5.3 software.Two individuals checked the inputs for accuracy.Continuous variables were described using mean difference and standard deviation,and outcome effect sizes were expressed using ratio OR and 95%confidence interval(CI).High heterogeneity was considered at(P<0.05,I2>50%),moderate heterogeneity at I2 from 25%to 50%,and low heterogeneity at(P≥0.05,I2<50%).RESULTS Following a comprehensive literature search,review,and analysis,six articles were selected for inclusion in this study.This selection comprised five articles in English and one in Chinese,with publication years spanning from 2016 to 2022.The study with the largest sample size,conducted by Seungbae in 2021,included a total of 304 cases.Statistical analysis:A total of 1063 patients were included in this meta-analysis.The main outcome indicators were:Surgical time:The Gamma3U blade system had a longer surgical time compared to Gamma3 nails(P=0.006,I2=76%).Tip-apex distance:No statistical significance or heterogeneity was observed(P=0.65,I2=0%).Harris Hip score:No statistical significance was found,and low heterogeneity was detected(P=0.26,I2=22%).Union time:No statistical significance was found,and high heterogeneity was detected(P=0.05,I2=75%).CONCLUSION Our study indicated that the Gamma3 system reduces operative time compared to the Gamma3 U-blade system in treating intertrochanteric fractures.Both surgical methods proved to be safe and effective for this patient group.These findings may offer valuable insights and guidance for future surgical protocols in hip fracture patients.
文摘Several densities or probability laws of continuous random variables derive from the Euler Gamma function. These laws form the basis of sampling theory, namely hypothesis testing and estimation. Namely the gamma, beta, and Student law, through the chi-square law and the normal law are all distributions resulting from applications of Euleur functions.
基金supported by the National Natural Science Foundation of China(Nos.12322302,12275279 and U1931201)the National Key R&D Program of China(No.2023YFE0102300)+2 种基金the Project for Young Scientists in Basic Research of Chinese Academy of Sciences(No.YSBR-061)the Chinese Academy of Sciencesthe Entrepreneurship and Innovation Program of Jiangsu Province。
文摘The Giant Radio Array for Neutrino Detection(GRAND)is a proposed large-scale observatory designed to detect cosmic rays,gamma-rays,and neutrinos with energies exceeding 100 Pe V.The GRANDProto300 experiment is proposed as the early stage of the GRAND project,consisting of a hybrid array of radio antennas and scintillator detectors.The latter,as a mature and traditional detector,is used to cross-check the nature of the candidate events selected from radio observations.In this study,we developed a simulation software called G4GRANDProto300,based on the Geant4 software package,to optimize the spacing of the scintillator detector array and to investigate its effective area.The analysis was conducted at various zenith angles under different detector spacings,including 300,500,600,700,and 900 m.Our results indicate that,for large zenith angles used to search for cosmic-ray in the GRAND project,the optimized effective area is with a detector spacing of 500 m.The G4GRANDProto300 software that we developed could be used to further optimize the layout of the particle detector array in future work.
文摘Background: This study aimed to evaluate the diagnostic value of interferon-γ release assay (IGRA), a sensitive microbiological diagnostic method, in children and adolescents with suspected tuberculosis in a country with a high burden of tuberculosis. Method: This study included 581 children and adolescents aged 4 - 19 years who were suspected of having tuberculosis, were latently infected with Mycobacterium tuberculosis, and had received at least one dose of BCG vaccine between April 17, 2019, and February 24, 2021. The study evaluated the TST results of 106 patients who had a positive Quantiferon test and were suspected of having tuberculosis. Results: The study included 581 patients aged between 4 and 19 years. Of these, 106 patients tested positive for the Quantiferon test, while 19 were indeterminate and 456 were negative. The Quantiferon test positivity rate was 18.24%. Among the 106 QFT-Plus-positive cases, 23 patients also tested positive for TST. The difference in distribution was found to be statistically significant. Conclusion: The QFT-Plus test is considered an alternative to TST and other microbiological diagnostic methods for early tuberculosis diagnosis, particularly in children and adolescents.
文摘According to a recent calculation, 10<sup>58</sup> erg of radiant energy was released by Sgr A*, when it formed the Fermi bubbles. Here, it is argued that this explosion constituted a long gamma-ray burst. .
文摘Lorentz Invariance is a foundational principle in modern physics, but some recent quantum gravity theories have hinted that it may be violated at extremely high energies. Gamma-ray bursts (GRBs) provide a promising tool for checking and constraining any deviations from Lorentz Invariance due to their huge energies and cosmological distances. Gamma-ray bursts, which are the most intense and powerful explosions in the universe, are traditionally divided into long bursts whose observed duration exceeds 2 s, and short bursts whose observed duration is less than 2 s. In this study, we employ a recent sample of 46 short GRBs to check for any deviation from Lorentz Invariance. We analyze the spectral lag of the bursts in our data sample and check for any redshift dependence in the GRB rest frame, which would indicate a violation of Lorentz Invariance. Our results are consistent, to within 1σ, with no deviation from Lorentz Invariance.
文摘为了研究不同码型的卷积码在水下湍流信道中的误码率(BER)性能,采用接受-拒绝采样模拟湍流信道乘性干扰,并选择二进制相移键控(BPSK)调制方式,建立Gamma-Gamma湍流信道通信系统仿真模型。仿真结果表明:在不同强度的湍流信道中,采用卷积码编码均能提升系统的BER性能;卷积码的码率越小,系统BER性能提升越显著;随着信噪比(SNR)增大,记忆深度越长,系统BER下降速度越快;采用软译码比采用硬译码时增益至少提升2.82 d B;卷积码的解码不仅受当前信息的影响,还与之前的码元信息有关。
文摘Background and Aims While chest X-ray (CXR) has been a conventional tool in intensive care units (ICUs) to identify lung pathologies, computed tomography (CT) scan remains the gold standard. Use of lung ultrasound (LUS) in resource-rich ICUs is still under investigation. The present study compares the utility of LUS to that of CXR in identifying pulmonary edema and pleural effusion in ICU patients. In addition, consolidation and pneumothorax were analyzed as secondary outcome measures. Material and Methods This is a prospective, single centric, observational study. Patients admitted in ICU were examined for lung pathologies, using LUS by a trained intensivist;and CXR done within 4 hours of each other. The final diagnosis was ascertained by an independent senior radiologist, based on the complete medical chart including clinical findings and the results of thoracic CT, if available. The results were compared and analyzed. Results Sensitivity, specificity and diagnostic accuracy of LUS was 95%, 94.4%, 94.67% for pleural effusion;and 98.33%, 97.78%, 98.00% for pulmonary edema respectively. Corresponding values with CXR were 48.33%, 76.67%, 65.33% for pleural effusion;and 36.67%, 82.22% and 64.00% for pulmonary edema respectively. Sensitivity, specificity and diagnostic accuracy of LUS was 91.30%, 96.85%, 96.00% for consolidation;and 100.00%, 79.02%, 80.00% for pneumothorax respectively. Corresponding values with CXR were 60.87%, 81.10%, 78.00% for consolidation;and 71.3%, 97.20%, 96.00% for pneumothorax respectively. Conclusion LUS has better diagnostic accuracy in diagnosis of pleural effusion and pulmonary edema when compared with CXR and is thus recommended as an effective alternative for diagnosis of these conditions in acute care settings. Our study recommends that a thoracic CT scan can be avoided in most of such cases.
基金supported by the National Natural Science Foundation of China,No.82071254(to WZ).
文摘Long-term levodopa administration can lead to the development of levodopa-induced dyskinesia.Gamma oscillations are a widely recognized hallmark of abnormal neural electrical activity in levodopa-induced dyskinesia.Currently,studies have reported increased oscillation power in cases of levodopa-induced dyskinesia.However,little is known about how the other electrophysiological parameters of gamma oscillations are altered in levodopa-induced dyskinesia.Furthermore,the role of the dopamine D3 receptor,which is implicated in levodopa-induced dyskinesia,in movement disorder-related changes in neural oscillations is unclear.We found that the cortico-striatal functional connectivity of beta oscillations was enhanced in a model of Parkinson’s disease.Furthermore,levodopa application enhanced cortical gamma oscillations in cortico-striatal projections and cortical gamma aperiodic components,as well as bidirectional primary motor cortex(M1)↔dorsolateral striatum gamma flow.Administration of PD128907(a selective dopamine D3 receptor agonist)induced dyskinesia and excessive gamma oscillations with a bidirectional M1↔dorsolateral striatum flow.However,administration of PG01037(a selective dopamine D3 receptor antagonist)attenuated dyskinesia,suppressed gamma oscillations and cortical gamma aperiodic components,and decreased gamma causality in the M1→dorsolateral striatum direction.These findings suggest that the dopamine D3 receptor plays a role in dyskinesia-related oscillatory activity,and that it has potential as a therapeutic target for levodopa-induced dyskinesia.
文摘We present a pilot study of time delays Δt in four GRB Radio Afterglow emissions, i.e., delays in the arrival times of radio waves of different frequencies emanating from eight GRB Radio Afterglows. Unlike in most studies on this phenomenon, we do not assume that this time delay is due to the Photon being endowed with a non-zero mass, but that this may very well be due to the interstellar space being a cold rarefied cosmic plasma, which medium’s Electrons interact with the electric component of the Photon, thus generating tiny currents that lead to dispersion, hence, a frequency (v) dependent speed of Light where this speed scales off as v<sup>-</sup><sup>1</sup>. The said interaction is such that, lower frequency Photons will propagate at lower speeds than higher frequency Photons thus leading to the observed time delays in the arrivals times of Photons of different frequencies. In reasonable accord with the proposed model, we find that for four of these GRB afterglows, there is a strong unsolicited correlation between the observed time delays and the frequency. If this model can be corroborated by a large enough data set, there is hope that this same model might lead to a better understanding of the observed time delays in GRBs.
文摘Ray tracing is a computer graphics method that renders images realistically. As the name suggests, this technique primarily traces the path of light rays interacting with objects in a scene [1], permitting the calculation of lighting and reflecting impact [2]. As ray tracing is a time-consuming process, the need for parallelization to solve this problem arises. One downside of this solution is the existence of race conditions. In this work, we explore and experiment with a different, well-known solution for this race condition. Starting with the introduction and the background section, a brief overview of the topic is followed by a detailed part of how the race conditions may occur in the case of the ray tracing algorithm. Continuing with the methods and results section, we have used OpenMP to parallelize the Ray tracing algorithm with the different compiler directives critical, atomic, and first-private. Hence, it concluded that both critical and atomic are not efficient solutions to produce a good-quality picture, but first-private succeeded in producing a high-quality picture.
文摘Two new solutions of the homogeneous diffusion equation in 1D are derived in the presence of losses and a trigonometric profile for a profile of density. A simulation for the ankle in the energy distribution of cosmic rays (CRs) is provided in the framework of the fine tuning of the involved parameters. A theoretical image for the overall diffusion of CRs in galactic coordinates is provided.