目的对发生在社区蛋糕店的一起食物中毒事件进行流行病学调查分析,查明致病因子、致病食品及其污染来源,为今后预防类似事件的发生提供参考。方法采用现场流行病学调查、食品卫生学调查和实验室检验相结合的方法。结果本次事件共发现病...目的对发生在社区蛋糕店的一起食物中毒事件进行流行病学调查分析,查明致病因子、致病食品及其污染来源,为今后预防类似事件的发生提供参考。方法采用现场流行病学调查、食品卫生学调查和实验室检验相结合的方法。结果本次事件共发现病例14例,病例的临床表现相似,主要为腹泻、腹痛、发热、呕吐。发病潜伏期中位数为9.25 h(3.2~14.6 h)。所有病例发病前均食用过HG糕店制售的三文治,经剂量反应关系分析,认为三文治食用量和疾病严重程度存在相关性(r=0.583,P=0.029)。病例肛拭子、呕吐物及粪便、剩余三文治和三文治生产原料等标本中均检出肠炎沙门氏菌,不同来源标本中分离到的阳性菌株经脉冲场凝胶电泳(pulsed-field gel electrophoresis,PFGE)分子分型分析具有同源性。结论该起事件是一起因食用社区蛋糕店制售的受沙门氏菌污染的三文治引起的食物中毒事件。展开更多
Image segmentation is a key and fundamental problem in image processing,computer graphics,and computer vision.Level set based method for image segmentation is used widely for its topology flexibility and proper mathem...Image segmentation is a key and fundamental problem in image processing,computer graphics,and computer vision.Level set based method for image segmentation is used widely for its topology flexibility and proper mathematical formulation.However,poor performance of existing level set models on noisy images and weak boundary limit its application in image segmentation.In this paper,we present a region consistency constraint term to measure the regional consistency on both sides of the boundary,this term defines the boundary of the image within a range,and hence increases the stability of the level set model.The term can make existing level set models significantly improve the efficiency of the algorithms on segmenting images with noise and weak boundary.Furthermore,this constraint term can make edge-based level set model overcome the defect of sensitivity to the initial contour.The experimental results show that our algorithm is efficient for image segmentation and outperform the existing state-of-art methods regarding images with noise and weak boundary.展开更多
Background Valvular heart disease(VHD)is expected to become more prevail as the population ages and disproportionately affects older adults.However,direct comparison of clinical characteristics,sonographic diagnosis,a...Background Valvular heart disease(VHD)is expected to become more prevail as the population ages and disproportionately affects older adults.However,direct comparison of clinical characteristics,sonographic diagnosis,and outcomes in VHD patients aged over 65 years is scarce.The objective of this study was to evaluate the differences in clinical characteristics and prognosis in two age-groups of geriatric patients with VHD.Methods We retrospectively enrolled consecutive individuals aged>65 years from Guangdong Provincial Peopled Hospital and screened for VHD using transthoracic echocardiography(TTE)or transesophageal echocardiography(TEE).Finally,260(48.9%)patients were in the 65-74 years group,and 272(51.1%)were in the>75-year group.Factors that affected long-term survival was explored.A multivariable Cox hazards regression was performed to identify the predictors of major adverse cardiac events(MACEs)in each group.Results In our population,the older group were more likely to have chronic obstructive pulmonary disease(COPD),degenerative VHD,but with less rheumatic VHD,aortic stenosis(AS)and mitral stenosis(MS).Compared with those aged 65-74 years,the older group had a higher incidence of all-cause death(10.0%vs.16.5%,P=0.027),ischemic stroke(13.5%vs.20.2%,P=0.038)and MACEs(37.3%vs.48.2%,P=0.011)at long-term follow-up.In multivariable Cox regression analysis,mitral regurgitation,a history of COPD,chronic kidney disease,diabetes,hypertension,atrial fibrillation and New York Heart Association(NYHA)functional class were identified as independent predictors of MACEs in the older group.Conclusion Advanced age profoundly affect prognosis and different predictors were associated with MACEs in geriatric patients with VHD.展开更多
Energy minimization has been widely used for constructing curve and surface in the fields such as computer-aided geometric design, computer graphics. However, our testing examples show that energy minimization does no...Energy minimization has been widely used for constructing curve and surface in the fields such as computer-aided geometric design, computer graphics. However, our testing examples show that energy minimization does not optimize the shape of the curve sometimes. This paper studies the relationship between minimizing strain energy and curve shapes, the study is carried out by constructing a cubic Hermite curve with satisfactory shape. The cubic Hermite curve interpolates the positions and tangent vectors of two given endpoints. Computer simulation technique has become one of the methods of scientific discovery, the study process is carried out by numerical computation and computer simulation technique. Our result shows that： （1） cubic Hermite curves cannot be constructed by solely minimizing the strain energy; （2） by adoption of a local minimum value of the strain energy, the shapes of cubic Hermite curves could be determined for about 60 percent of all cases, some of which have unsatisfactory shapes, however. Based on strain energy model and analysis, a new model is presented for constructing cubic Hermite curves with satisfactory shapes, which is a modification of strain energy model. The new model uses an explicit formula to compute the magnitudes of the two tangent vectors, and has the properties： （1） it is easy to compute; （2） it makes the cubic Hermite curves have satisfactory shapes while holding the good property of minimizing strain energy for some cases in curve construction. The comparison of the new model with the minimum strain energy model is included.展开更多
Recently, significant oil discoveries have been made in the shallower pay zones of the Jurassic Badaowan Formation (J_(1)b) in the Mahu Sag, Junggar Basin, Northwest China. However, little work has been done on the ge...Recently, significant oil discoveries have been made in the shallower pay zones of the Jurassic Badaowan Formation (J_(1)b) in the Mahu Sag, Junggar Basin, Northwest China. However, little work has been done on the geochemical characteristics and origins of the oil in the J_(1)b reservoir. This study analyzes 44 oil and 14 source rock samples from the area in order to reveal their organic geochemical characteristics and the origins of the oils. The J_(1)b oils are characterized by a low Pr/Ph ratio and high β-carotene and gammacerane indices, which indicate that they were mainly generated from source rocks deposited in a hypersaline environment. The oils are also extremely enhanced in C_(29) regular steranes, possibly derived from halophilic algae. Oil-source correlation shows that the oils were derived from the Lower Permian Fengcheng Formation (P_(1)f) source rocks, which were deposited in a strongly stratified and highly saline water column with a predominance of algal/bacterial input in the organic matter. The source rocks of the Middle Permian lower-Wuerhe Formation (P_(2)w), which were deposited in fresh to slightly saline water conditions with a greater input of terrigenous organic matter, make only a minor contribution to the J_(1)b oils. The reconstruction of the oil accumulation process shows that the J_(1)b oil reservoir may have been twice charged during Late Jurassic–Early Cretaceous and the Paleogene–Neogene, respectively. A large amount volume of hydrocarbons generated in the P_(1)f source rock and leaked from T_(1)b oil reservoirs migrated along faults connecting source beds and shallow-buried secondary faults into Jurassic traps, resulting in large-scale accumulations in J_(1)b. These results are crucial for understanding the petroleum system of the Mahu Sag and will provide valuable guidance for petroleum exploration in the shallower formations in the slope area of the sag.展开更多
文摘目的对发生在社区蛋糕店的一起食物中毒事件进行流行病学调查分析,查明致病因子、致病食品及其污染来源,为今后预防类似事件的发生提供参考。方法采用现场流行病学调查、食品卫生学调查和实验室检验相结合的方法。结果本次事件共发现病例14例,病例的临床表现相似,主要为腹泻、腹痛、发热、呕吐。发病潜伏期中位数为9.25 h(3.2~14.6 h)。所有病例发病前均食用过HG糕店制售的三文治,经剂量反应关系分析,认为三文治食用量和疾病严重程度存在相关性(r=0.583,P=0.029)。病例肛拭子、呕吐物及粪便、剩余三文治和三文治生产原料等标本中均检出肠炎沙门氏菌,不同来源标本中分离到的阳性菌株经脉冲场凝胶电泳(pulsed-field gel electrophoresis,PFGE)分子分型分析具有同源性。结论该起事件是一起因食用社区蛋糕店制售的受沙门氏菌污染的三文治引起的食物中毒事件。
基金supported in part by the NSFC-Zhejiang Joint Fund of the Integration of Informatization and Industrialization(U1609218)NSFC(61772312,61373078,61772253)+1 种基金the Key Research and Development Project of Shandong Province(2017GGX10110)NSF of Shandong Province(ZR2016FM21,ZR2016FM13)
文摘Image segmentation is a key and fundamental problem in image processing,computer graphics,and computer vision.Level set based method for image segmentation is used widely for its topology flexibility and proper mathematical formulation.However,poor performance of existing level set models on noisy images and weak boundary limit its application in image segmentation.In this paper,we present a region consistency constraint term to measure the regional consistency on both sides of the boundary,this term defines the boundary of the image within a range,and hence increases the stability of the level set model.The term can make existing level set models significantly improve the efficiency of the algorithms on segmenting images with noise and weak boundary.Furthermore,this constraint term can make edge-based level set model overcome the defect of sensitivity to the initial contour.The experimental results show that our algorithm is efficient for image segmentation and outperform the existing state-of-art methods regarding images with noise and weak boundary.
基金National Nature Science Foundation of China (No.81370295)Science and Technology Program of Guangdong Province, China (No.2017A020215054)Science and Technology Planning of Guangzhou City, China (No.2014B 070705005)
文摘Background Valvular heart disease(VHD)is expected to become more prevail as the population ages and disproportionately affects older adults.However,direct comparison of clinical characteristics,sonographic diagnosis,and outcomes in VHD patients aged over 65 years is scarce.The objective of this study was to evaluate the differences in clinical characteristics and prognosis in two age-groups of geriatric patients with VHD.Methods We retrospectively enrolled consecutive individuals aged>65 years from Guangdong Provincial Peopled Hospital and screened for VHD using transthoracic echocardiography(TTE)or transesophageal echocardiography(TEE).Finally,260(48.9%)patients were in the 65-74 years group,and 272(51.1%)were in the>75-year group.Factors that affected long-term survival was explored.A multivariable Cox hazards regression was performed to identify the predictors of major adverse cardiac events(MACEs)in each group.Results In our population,the older group were more likely to have chronic obstructive pulmonary disease(COPD),degenerative VHD,but with less rheumatic VHD,aortic stenosis(AS)and mitral stenosis(MS).Compared with those aged 65-74 years,the older group had a higher incidence of all-cause death(10.0%vs.16.5%,P=0.027),ischemic stroke(13.5%vs.20.2%,P=0.038)and MACEs(37.3%vs.48.2%,P=0.011)at long-term follow-up.In multivariable Cox regression analysis,mitral regurgitation,a history of COPD,chronic kidney disease,diabetes,hypertension,atrial fibrillation and New York Heart Association(NYHA)functional class were identified as independent predictors of MACEs in the older group.Conclusion Advanced age profoundly affect prognosis and different predictors were associated with MACEs in geriatric patients with VHD.
基金Supported by the National Natural Science Foundation of China(61173174,61103150,61373078)the NSFC Joint Fund with Guangdong under Key Project(U1201258)the National Research Foundation for the Doctoral Program of Higher Education of China(20110131130004)
文摘Energy minimization has been widely used for constructing curve and surface in the fields such as computer-aided geometric design, computer graphics. However, our testing examples show that energy minimization does not optimize the shape of the curve sometimes. This paper studies the relationship between minimizing strain energy and curve shapes, the study is carried out by constructing a cubic Hermite curve with satisfactory shape. The cubic Hermite curve interpolates the positions and tangent vectors of two given endpoints. Computer simulation technique has become one of the methods of scientific discovery, the study process is carried out by numerical computation and computer simulation technique. Our result shows that： （1） cubic Hermite curves cannot be constructed by solely minimizing the strain energy; （2） by adoption of a local minimum value of the strain energy, the shapes of cubic Hermite curves could be determined for about 60 percent of all cases, some of which have unsatisfactory shapes, however. Based on strain energy model and analysis, a new model is presented for constructing cubic Hermite curves with satisfactory shapes, which is a modification of strain energy model. The new model uses an explicit formula to compute the magnitudes of the two tangent vectors, and has the properties： （1） it is easy to compute; （2） it makes the cubic Hermite curves have satisfactory shapes while holding the good property of minimizing strain energy for some cases in curve construction. The comparison of the new model with the minimum strain energy model is included.
基金supported by the National Natural Science Foundation of China(No.41802179)Sichuan Science and Technology Program(No.2019YFH0037)the Foundation of the State Key Laboratory of Petroleum Resources and Prospecting,China University of Petroleum,Beijing(No.PRP/open-1906).
文摘Recently, significant oil discoveries have been made in the shallower pay zones of the Jurassic Badaowan Formation (J_(1)b) in the Mahu Sag, Junggar Basin, Northwest China. However, little work has been done on the geochemical characteristics and origins of the oil in the J_(1)b reservoir. This study analyzes 44 oil and 14 source rock samples from the area in order to reveal their organic geochemical characteristics and the origins of the oils. The J_(1)b oils are characterized by a low Pr/Ph ratio and high β-carotene and gammacerane indices, which indicate that they were mainly generated from source rocks deposited in a hypersaline environment. The oils are also extremely enhanced in C_(29) regular steranes, possibly derived from halophilic algae. Oil-source correlation shows that the oils were derived from the Lower Permian Fengcheng Formation (P_(1)f) source rocks, which were deposited in a strongly stratified and highly saline water column with a predominance of algal/bacterial input in the organic matter. The source rocks of the Middle Permian lower-Wuerhe Formation (P_(2)w), which were deposited in fresh to slightly saline water conditions with a greater input of terrigenous organic matter, make only a minor contribution to the J_(1)b oils. The reconstruction of the oil accumulation process shows that the J_(1)b oil reservoir may have been twice charged during Late Jurassic–Early Cretaceous and the Paleogene–Neogene, respectively. A large amount volume of hydrocarbons generated in the P_(1)f source rock and leaked from T_(1)b oil reservoirs migrated along faults connecting source beds and shallow-buried secondary faults into Jurassic traps, resulting in large-scale accumulations in J_(1)b. These results are crucial for understanding the petroleum system of the Mahu Sag and will provide valuable guidance for petroleum exploration in the shallower formations in the slope area of the sag.
