Background: Cerebral and retinal vessels behave similarly under the influence of vascular risk factors. Several groups have shown that retinal microvascular abnormalities represent an independent risk factor with rega...Background: Cerebral and retinal vessels behave similarly under the influence of vascular risk factors. Several groups have shown that retinal microvascular abnormalities represent an independent risk factor with regard to strokes and heart attacks. Aim of the Study: The aim of this study was to perform a prospective screening examinationwith regard to retinalmicrovascular abnormalities as well as an extended vessel diagnosis in a subgroup of patients with lower arteriovenous risk values. Methods: In the course of a prospective cross-sectional study (“Talking Eyes”) between 1.9.2001 and 1.8.2002 a telemedical-supported screening of the retina (study 1) was carried out in 7,163 subjects. The patients were selected without any inclusion or exclusion criteria. The mean age was 48.2±8 years (18-83 years) with a sex distribution of 39.2%females to 60.8%males. Digital fundus photos of the right and left eyes were taken for all patients. The pictures were taken without pupil dilation using a CANON-NM camera. The pictures and case histories were stored in a central server using web-based software (MedStage, Siemens). In a central reading centre, the arteriovenous ratio of both eyes was determined telemedically using the Parr-Hubbard formula and the retinas subjected to a standardised examination by an ophthalmologist. The retinal risk factor was calculated on the basis of the arteriovenous ration, the presence of microvascular abnormalities and the case history. The reproducibility of measurement of the arteriovenous ratio (Kronbach alpha coefficient) was evaluated by double measurements on 1,332 images. In a subgroup of study 1 with arteriovenous ratio values < 0.76 (N=107), an extended vessel diagnosis with measurement of 24-h blood pressure and vessel-relevant blood values (homocysteine, cholesterol, LDL, HDL, CRP, TG, HbA1c) was carried out (study II). Results: Study 1: The Kronbach alpha coefficient as a measure of reproducibility amounted to 0.77. The mean arteriovenous ratio of the retinal vessels was 0.83±0.09 and showed a pronounced age dependence (R=0.9, p< 0.0001). On multivariate testing the arteriovenous ratio correlated significantly (R=0.33, p< 0.001) with the factors age, systolic blood pressure, diastolic blood pressure and body mass index. Diastolic blood pressure followed by age had the largest influence. The prevalence of microvascular abnormalities in the right (RE) and left (LE)-eyes, respectively were: cotton wool foci RE 0.0015%, LE 0.003%, retinal haemorrhage RE 0.1%, LE 0.1%, focal stenoses RE 3.4%, LE 3.4%, tortuositas vasorumRE 4.1%, LE 4.0%, arteriovenous crossing signs RE 11.2%, LE 11.2%. On multivariate testing the occurrence of microvascular abnormalities correlated significantly (R=0.38, p < 0.001) with the factors high blood pressure known from case history, body mass index, and gender. Arterial hypertension had the strongest influence followed by diastolic blood pressure. The calculated retinal risk factor correlated with the prevalence of angina pectoris. Study 11: 2/3 of the subjects with arteriovenous risk factor values < 0.76 exhibited pathologically high 24-h blood pressure values. For these patients there were significant correlations between the arteriovenous ratio and the low-density lipoprotein concentration as well as the Framingham risk score. Conclusion: In the course of a prospective, telemedical-supported screening examination of the retinal vessels of more than 7,000 subjects the arteriovenous ratio exhibited a strong dependence on age and blood pressure. Among the subjects with lowered arteriovenous ratio values, 2/3 exhibited arterial hypertension in the 24-h blood pressure determination.展开更多
Comparative analyses were conducted to compare the effects of the behavioral characteristics of the drivers of taxis and private cars on the capacity and safety of signalized intersections. Data were collected at sixt...Comparative analyses were conducted to compare the effects of the behavioral characteristics of the drivers of taxis and private cars on the capacity and safety of signalized intersections. Data were collected at sixteen signalized intersections in the Nanjing area in China. The risk-taking behaviors of the drivers of taxis and private cars were compared. The results suggest that 19.9% of taxi drivers have committed at least one of the identified risky behaviors, which is 2.37 times as high as that of the drivers of private cars(8.4%). The traffic conflicts technique was used to estimate the safety effects of taxis and private cars. The overall conflict rate for taxis is 21.4% higher than that for private cars, implying that taxis are more likely to be involved in conflicts. Almost all of the identified traffic conflicts can be attributed to certain levels of risk-taking behaviors committed by either taxi drivers or the drivers of private cars, and taxi drivers are more likely to be at fault in a conflict. Failure to yield to right-of-way and improper lane change is the leading causes of the conflicts in which taxis are at-fault. The research team further studied the effects of taxis on the queue discharge characteristics at signalized intersections. The results show that the presence of taxis significantly reduces both start-up lost time and saturation headways. The effects of taxis on saturation flow rates are dependent on the proportion of taxis in the discharge flow, and the saturation flow rates increase with the increase in the proportion of taxis. The adjustment factors for various proportions of taxis for different turning movements are then calculated to quantitatively evaluate the effects of taxis on the capacity of signalized intersections.展开更多
This study combined fault identification with a deep learning algorithm and applied a convolutional neural network(CNN)design based on an improved balanced crossentropy(BCE)loss function to address the low accuracy in...This study combined fault identification with a deep learning algorithm and applied a convolutional neural network(CNN)design based on an improved balanced crossentropy(BCE)loss function to address the low accuracy in the intelligent identification of seismic faults and the slow training speed of convolutional neural networks caused by unbalanced training sample sets.The network structure and optimal hyperparameters were determined by extracting feature maps layer by layer and by analyzing the results of seismic feature extraction.The BCE loss function was used to add the parameter which is the ratio of nonfaults to the total sample sets,thereby changing the loss function to find the reference of the minimum weight parameter and adjusting the ratio of fault to nonfault data.The method overcame the unbalanced number of sample sets and improved the iteration speed.After a brief training,the accuracy could reach more than 95%,and gradient descent was evident.The proposed method was applied to fault identification in an oilfield area.The trained model can predict faults clearly,and the prediction results are basically consistent with an actual case,verifying the effectiveness and adaptability of the method.展开更多
With the aid of computation, we consider the variable-coefficient coupled nonlinear Schrodinger equations with the effects of group-velocity dispersion, self-phase modulation and cross-phase modulation, which have pot...With the aid of computation, we consider the variable-coefficient coupled nonlinear Schrodinger equations with the effects of group-velocity dispersion, self-phase modulation and cross-phase modulation, which have potential applications in the long-distance communication of two-pulse propagation in inhomogeneous optical fibers. Based on the obtained nonisospectral linear eigenvalue problems （i.e. Lax pair）, we construct the Darboux transformation for such a model to derive the optical soliton solutions. In addition, through the one- and two-soliton-like solutions, we graphically discuss the features of picosecond solitons in inhomogeneous optical fibers.展开更多
Objective:To observe the therapeutic efficacy of sinew-bone balancing manipulation plus exercise therapy in treating postures of primary school students with upper crossed syndrome(UCS).Methods:Sixty pupils with UCS w...Objective:To observe the therapeutic efficacy of sinew-bone balancing manipulation plus exercise therapy in treating postures of primary school students with upper crossed syndrome(UCS).Methods:Sixty pupils with UCS were divided into an exercise group and a combination group using the random number table method,with 30 cases in each group.The combination group received treatments of sinew-bone balancing manipulation plus exercise therapy,while the exercise group received exercise therapy alone.The two groups received interventions once every other day,for a total of 1 month.The sagittal static posture assessment total score,forward head angle(FHA)and forward shoulder angle(FSA)were compared before and after treatment;the sagittal static assessment total score,FHA and FSA were compared between the exercise group and the combination group.Results:Before treatment,there were no significant differences comparing the sagittal static posture assessment total score,FHA and FSA between the two groups(all P>0.05);after treatment,the sagittal static posture assessment total score,FHA and FSA decreased in the two groups,with intra-group statistical significance(all P<0.01),and were lower in the combination group than in the exercise group,with inter-group statistical significance(all P<0.01).Conclusion:Sinew-bone balancing manipulation plus exercise therapy can notably improve the FHA and FSA and reduce the sagittal static posture total score in pupils with UCS,so as to correct the bad postures and adjust UCS physique.It can produce more significant efficacy compared with exercise therapy alone.展开更多
文摘Background: Cerebral and retinal vessels behave similarly under the influence of vascular risk factors. Several groups have shown that retinal microvascular abnormalities represent an independent risk factor with regard to strokes and heart attacks. Aim of the Study: The aim of this study was to perform a prospective screening examinationwith regard to retinalmicrovascular abnormalities as well as an extended vessel diagnosis in a subgroup of patients with lower arteriovenous risk values. Methods: In the course of a prospective cross-sectional study (“Talking Eyes”) between 1.9.2001 and 1.8.2002 a telemedical-supported screening of the retina (study 1) was carried out in 7,163 subjects. The patients were selected without any inclusion or exclusion criteria. The mean age was 48.2±8 years (18-83 years) with a sex distribution of 39.2%females to 60.8%males. Digital fundus photos of the right and left eyes were taken for all patients. The pictures were taken without pupil dilation using a CANON-NM camera. The pictures and case histories were stored in a central server using web-based software (MedStage, Siemens). In a central reading centre, the arteriovenous ratio of both eyes was determined telemedically using the Parr-Hubbard formula and the retinas subjected to a standardised examination by an ophthalmologist. The retinal risk factor was calculated on the basis of the arteriovenous ration, the presence of microvascular abnormalities and the case history. The reproducibility of measurement of the arteriovenous ratio (Kronbach alpha coefficient) was evaluated by double measurements on 1,332 images. In a subgroup of study 1 with arteriovenous ratio values < 0.76 (N=107), an extended vessel diagnosis with measurement of 24-h blood pressure and vessel-relevant blood values (homocysteine, cholesterol, LDL, HDL, CRP, TG, HbA1c) was carried out (study II). Results: Study 1: The Kronbach alpha coefficient as a measure of reproducibility amounted to 0.77. The mean arteriovenous ratio of the retinal vessels was 0.83±0.09 and showed a pronounced age dependence (R=0.9, p< 0.0001). On multivariate testing the arteriovenous ratio correlated significantly (R=0.33, p< 0.001) with the factors age, systolic blood pressure, diastolic blood pressure and body mass index. Diastolic blood pressure followed by age had the largest influence. The prevalence of microvascular abnormalities in the right (RE) and left (LE)-eyes, respectively were: cotton wool foci RE 0.0015%, LE 0.003%, retinal haemorrhage RE 0.1%, LE 0.1%, focal stenoses RE 3.4%, LE 3.4%, tortuositas vasorumRE 4.1%, LE 4.0%, arteriovenous crossing signs RE 11.2%, LE 11.2%. On multivariate testing the occurrence of microvascular abnormalities correlated significantly (R=0.38, p < 0.001) with the factors high blood pressure known from case history, body mass index, and gender. Arterial hypertension had the strongest influence followed by diastolic blood pressure. The calculated retinal risk factor correlated with the prevalence of angina pectoris. Study 11: 2/3 of the subjects with arteriovenous risk factor values < 0.76 exhibited pathologically high 24-h blood pressure values. For these patients there were significant correlations between the arteriovenous ratio and the low-density lipoprotein concentration as well as the Framingham risk score. Conclusion: In the course of a prospective, telemedical-supported screening examination of the retinal vessels of more than 7,000 subjects the arteriovenous ratio exhibited a strong dependence on age and blood pressure. Among the subjects with lowered arteriovenous ratio values, 2/3 exhibited arterial hypertension in the 24-h blood pressure determination.
基金Projects(51322810,50908050)supported by the National Natural Science Foundation of China
文摘Comparative analyses were conducted to compare the effects of the behavioral characteristics of the drivers of taxis and private cars on the capacity and safety of signalized intersections. Data were collected at sixteen signalized intersections in the Nanjing area in China. The risk-taking behaviors of the drivers of taxis and private cars were compared. The results suggest that 19.9% of taxi drivers have committed at least one of the identified risky behaviors, which is 2.37 times as high as that of the drivers of private cars(8.4%). The traffic conflicts technique was used to estimate the safety effects of taxis and private cars. The overall conflict rate for taxis is 21.4% higher than that for private cars, implying that taxis are more likely to be involved in conflicts. Almost all of the identified traffic conflicts can be attributed to certain levels of risk-taking behaviors committed by either taxi drivers or the drivers of private cars, and taxi drivers are more likely to be at fault in a conflict. Failure to yield to right-of-way and improper lane change is the leading causes of the conflicts in which taxis are at-fault. The research team further studied the effects of taxis on the queue discharge characteristics at signalized intersections. The results show that the presence of taxis significantly reduces both start-up lost time and saturation headways. The effects of taxis on saturation flow rates are dependent on the proportion of taxis in the discharge flow, and the saturation flow rates increase with the increase in the proportion of taxis. The adjustment factors for various proportions of taxis for different turning movements are then calculated to quantitatively evaluate the effects of taxis on the capacity of signalized intersections.
基金supported by the Natural Science Foundation of Shandong Province(ZR202103050722).
文摘This study combined fault identification with a deep learning algorithm and applied a convolutional neural network(CNN)design based on an improved balanced crossentropy(BCE)loss function to address the low accuracy in the intelligent identification of seismic faults and the slow training speed of convolutional neural networks caused by unbalanced training sample sets.The network structure and optimal hyperparameters were determined by extracting feature maps layer by layer and by analyzing the results of seismic feature extraction.The BCE loss function was used to add the parameter which is the ratio of nonfaults to the total sample sets,thereby changing the loss function to find the reference of the minimum weight parameter and adjusting the ratio of fault to nonfault data.The method overcame the unbalanced number of sample sets and improved the iteration speed.After a brief training,the accuracy could reach more than 95%,and gradient descent was evident.The proposed method was applied to fault identification in an oilfield area.The trained model can predict faults clearly,and the prediction results are basically consistent with an actual case,verifying the effectiveness and adaptability of the method.
基金Supported by the National Natural Science Foundation of China under Grant No.60772023 the Open Fund of the State Key Laboratory of Software Development Environment under Grant No.BUAA-SKLSDE-09KF-04+2 种基金Beijing University of Aeronautics and Astronautics,by the National Basic Research Program of China (973 Program) under Grant No.2005CB321901the Specialized Research Fund for the Doctoral Program of Higher Education under Grant Nos.20060006024 and 200800130006Chinese Ministry of Education
文摘With the aid of computation, we consider the variable-coefficient coupled nonlinear Schrodinger equations with the effects of group-velocity dispersion, self-phase modulation and cross-phase modulation, which have potential applications in the long-distance communication of two-pulse propagation in inhomogeneous optical fibers. Based on the obtained nonisospectral linear eigenvalue problems （i.e. Lax pair）, we construct the Darboux transformation for such a model to derive the optical soliton solutions. In addition, through the one- and two-soliton-like solutions, we graphically discuss the features of picosecond solitons in inhomogeneous optical fibers.
文摘Objective:To observe the therapeutic efficacy of sinew-bone balancing manipulation plus exercise therapy in treating postures of primary school students with upper crossed syndrome(UCS).Methods:Sixty pupils with UCS were divided into an exercise group and a combination group using the random number table method,with 30 cases in each group.The combination group received treatments of sinew-bone balancing manipulation plus exercise therapy,while the exercise group received exercise therapy alone.The two groups received interventions once every other day,for a total of 1 month.The sagittal static posture assessment total score,forward head angle(FHA)and forward shoulder angle(FSA)were compared before and after treatment;the sagittal static assessment total score,FHA and FSA were compared between the exercise group and the combination group.Results:Before treatment,there were no significant differences comparing the sagittal static posture assessment total score,FHA and FSA between the two groups(all P>0.05);after treatment,the sagittal static posture assessment total score,FHA and FSA decreased in the two groups,with intra-group statistical significance(all P<0.01),and were lower in the combination group than in the exercise group,with inter-group statistical significance(all P<0.01).Conclusion:Sinew-bone balancing manipulation plus exercise therapy can notably improve the FHA and FSA and reduce the sagittal static posture total score in pupils with UCS,so as to correct the bad postures and adjust UCS physique.It can produce more significant efficacy compared with exercise therapy alone.
