Combining the characteristics of peer-to-peer (P2P) and grid, a super-peer selection algorithm--SSABC is presented in the distributed network merging P2P and grid. The algorithm computes nodes capacities using their...Combining the characteristics of peer-to-peer (P2P) and grid, a super-peer selection algorithm--SSABC is presented in the distributed network merging P2P and grid. The algorithm computes nodes capacities using their resource properties provided by a grid monitoring and discovery system, such as available bandwidth, free CPU and idle memory, as well as the number of current connections and online time. when a new node joins the network and the super-peers are all saturated, it should select a new super-peer from the new node or joined nodes with the highest capacity. By theoretical analyses and simulation experiments, it is shown that super-peers selected by capacity can achieve higher query success rates and shorten the average hop count when compared with super-peers selected randomly, and they can also balance the network load when all super-peers are saturated. When the number of total nodes changes, the conclusion is still valid, which explains that the algorithm SSABC is feasible and stable.展开更多
Plane detection is a prerequisite for many computer vision tasks. This paper proposes a new method which can automatically detect planes from two projective images. Firstly, we modify Scott’s feature point matching m...Plane detection is a prerequisite for many computer vision tasks. This paper proposes a new method which can automatically detect planes from two projective images. Firstly, we modify Scott’s feature point matching method by post-processing its result with the concept of similarity, and then get the lines matching according to feature points matching based on the approximate invariance of the features’ distribution between two images. Finally, we group all feature points into subsets in terms of their geometric relations with feature lines as initial sets to estimate homography rather than by a random search strategy (like RANSAC) as in most existing methods. The proposed method is especially suitable to detecting planes in man-made scenes. This method is validated on real images.展开更多
In order to analyze the failure data from repairable systems, the homogeneous Poisson process (HPP) is usually used. In general, HPP cannot be applied to analyze the entire life cycle of a complex, re-pairable system ...In order to analyze the failure data from repairable systems, the homogeneous Poisson process (HPP) is usually used. In general, HPP cannot be applied to analyze the entire life cycle of a complex, re-pairable system because the rate of occurrence of failures (ROCOF) of the system changes over time rather than remains stable. However, from a practical point of view, it is always preferred to apply the simplest method to address problems and to obtain useful practical results. Therefore, we attempted to use the HPP model to analyze the failure data from real repairable systems. A graphic method and the Laplace test were also used in the analysis. Results of numerical applications show that the HPP model may be a useful tool for the entire life cycle of repairable systems.展开更多
The performance in vibration environment of switching apparatus containing mechanical contact is an important element when judging the apparatus’s reliability. A piecewise linear two-degrees-of-freedom mathematical m...The performance in vibration environment of switching apparatus containing mechanical contact is an important element when judging the apparatus’s reliability. A piecewise linear two-degrees-of-freedom mathematical model considering contact loss was built in this work, and the vibration performance of the model under random external Gaussian white noise excitation was investigated by using Monte Carlo simulation in Matlab/Simulink. Simulation showed that the spectral content and statistical characters of the contact force coincided strongly with reality. The random vibration character of the contact system was solved using time (numerical) domain simulation in this paper. Conclusions reached here are of great importance for reliability design of switching apparatus.展开更多
To obtain higher accurate position estimates, the stochastic model is estimated by using residual of observations, hence, the stochastic model describes the noise and bias in measurements more realistically. By using ...To obtain higher accurate position estimates, the stochastic model is estimated by using residual of observations, hence, the stochastic model describes the noise and bias in measurements more realistically. By using GPS data and broadcast ephemeris, the numerical results indicating the accurate position estimates at sub-meter level are obtainable.展开更多
Grassland fire is one of the most important disturbance factors in the natural ecosystems.This paper focuses on the spatial distribution of long-term grassland fire patterns in the Hulun Buir Grassland located in the ...Grassland fire is one of the most important disturbance factors in the natural ecosystems.This paper focuses on the spatial distribution of long-term grassland fire patterns in the Hulun Buir Grassland located in the northeast of Inner Mongolia Autonomous Region in China.The density or ratio of ignition can reflect the relationship between grassland fire and different ignition factors.Based on the relationship between the density or ratio of ignition in different range of each ignition factor and grassland fire events,an ignition probability model was developed by using binary logistic regression function and its overall accuracy averaged up to 81.7%.Meanwhile it was found that daily relative humidity,daily temperature,elevation,vegetation type,distance to county-level road,distance to town are more important determinants of spatial distribution of fire ignitions.Using Monte Carlo method,we developed a time-dependent stochastic ignition probability model based on the distribution of inter-annual daily relative humidity and daily temperature.Through this model,it is possible to estimate the spatial patterns of ignition probability for grassland fire,which will be helpful to the quantitative evaluation of grassland fire risk and its management in the future.展开更多
Objective:Nephron-sparing surgery(NSS) for small renal masses offers a similar functional and oncological outcome to that of radical surgery.Laparoendoscopic single-site surgery(LESS) emerges as an advanced alternativ...Objective:Nephron-sparing surgery(NSS) for small renal masses offers a similar functional and oncological outcome to that of radical surgery.Laparoendoscopic single-site surgery(LESS) emerges as an advanced alternative for reduced invasiveness and improves cosmesis;LESS is developing quickly and its indications have been expanded,but still in its infancy.The aim of this paper is to report our preliminary experience in transumbilical LESS partial nephrectomy(LESS-PN),so as to assess its utility, safety and efficacy.Methods:From August 2009 to October 2010,3 patients underwent transumbilical LESS-PN via a novel multi-channel TriPort by a single experienced urologist in our institution.Patient demographics,perioperative and follow-up data were prospectively collected and analyzed.Results:All the three procedures were successfully completed.A 5-mm ancillary trocar was utilized in all 3 cases.The mean operative duration was 226.3(210-254 min) with an estimated blood loss of 56.7 ml (20-100 ml).Mean warm ischemia time was 35.7 min(19-48 min).One patient was transfused due to postoperative bleeding. The recovery was uneventful and mean length of postoperative stay was 13 days(12-14 days).At the latest follow-up,all patients remained symptom-free and had normal renal function without evidence of recurrence,and they were delighted for a hidden transumbilical scar.Conclusion:Transumbilical LESS-PN is a feasible and safe procedure albeit extremely technically challenging.Surgical outcomes at a median follow-up of 2 years are promising,while currently it should be reserved for highly selected patients with favorable tumor anatomy and performed by a very experienced laparoscopic surgeon.展开更多
Banking institutions all over the world face significant challenge due to the cumulative loss due to defaults of borrowers of different types of loans. The cumulative default loss built up over a period of time could ...Banking institutions all over the world face significant challenge due to the cumulative loss due to defaults of borrowers of different types of loans. The cumulative default loss built up over a period of time could wipe out the capital cushion of the banks. The aim of this paper is to help the banks to forecast the cumulative loss and its volatility. Defaulting amounts are random and defaults occur at random instants of time. A non Markovian time dependent random point process is used to model the cumulative loss. The expected loss and volatility are evaluated analytically. They are functions of probability of default, probability of loss amount, recovery rate and time. Probability of default being the important contributor is evaluated using Hidden Markov modeling. Numerical results obtained validate the model.展开更多
Suppose {X,X n,n≥1} are the i.i.d. random variables with values in 2 type Banach space B,S n=∑nk=1X k,φ(x) is a increasing function on [0,+∞), φ(x)→+∞, and φ(x)x is no increasing; then we point out that the cl...Suppose {X,X n,n≥1} are the i.i.d. random variables with values in 2 type Banach space B,S n=∑nk=1X k,φ(x) is a increasing function on [0,+∞), φ(x)→+∞, and φ(x)x is no increasing; then we point out that the cluster set CS n2nφ(n) is ρK, where ρ= lim L 2nφ(n)<+∞, ∫ ∞e -ρ 2φ(x) 1xd x=+∞,X∈WM 2 0, and E‖X‖ 2φ(‖X‖)<+∞.展开更多
This paper addresses the available capacity and robust connectivity of time division duplex based wireless mesh networks (TDD-based WMNs). A stochastic model is presented for TDD-based WMNs. Considering the paramete...This paper addresses the available capacity and robust connectivity of time division duplex based wireless mesh networks (TDD-based WMNs). A stochastic model is presented for TDD-based WMNs. Considering the parameters that affect the network performance like ratio of control slots number to data slots number, collision probability, node density and average hopcounts, the availa- ble capacity for each node is inferred. Meanwhile, the order of transmission range for robust connec- tivity of large scale WMNs is derived. With the stochastic model and inferred available capacity per node, the performance of TDD-based WMNs using IEEE 802.16 standard is analyzed under various conditions. Simulation results indicate that the available capacity of IEEE 802.16-based TDD-based WMNs and the theoretical result have the same increasing and decreasing trend as the node density increases. Simulation results also illustrate the optimal value of the ratio of control slots number to data slots number that maximizes the available capacity.展开更多
A novel approach was proposed to allocate spinning reserve for dynamic economic dispatch.The proposed approach set up a two-stage stochastic programming model to allocate reserve.The model was solved using a decompose...A novel approach was proposed to allocate spinning reserve for dynamic economic dispatch.The proposed approach set up a two-stage stochastic programming model to allocate reserve.The model was solved using a decomposed algorithm based on Benders' decomposition.The model and the algorithm were applied to a simple 3-node system and an actual 445-node system for verification,respectively.Test results show that the model can save 84.5 US $ cost for the testing three-node system,and the algorithm can solve the model for 445-node system within 5 min.The test results also illustrate that the proposed approach is efficient and suitable for large system calculation.展开更多
Objective: The aim of this study was to explore the relationship between p53 gene and triple-negative breast cancer (TNBC), and determine that whether p53 gene could be a new effective therapeutic target. Methods:...Objective: The aim of this study was to explore the relationship between p53 gene and triple-negative breast cancer (TNBC), and determine that whether p53 gene could be a new effective therapeutic target. Methods: We identified studies with quantitative data on the relation of p53 gene and TNBC through searching 12 databases online (Oct. 1999-Oct. 2012) and reviewing the references, which were written in English or Chinese. Summary estimates of odds ratio (OR) was calculated using the fixed-effects model or the random-effects model as appropriate. Results: We identified 12 eligible stud- ies with 1532 cases of TNBC patients and 6329 controls of non-TNBC patients. The test for homogeneity resulted in X^2 = 200.16 (P 〈 0.05), it showed significant heterogeneity so that a random effect model was applied. Our results showed that the expression of p53 gene could be much stronger in TNBC group than that in non-TNBC group [OR = 2.10, 95% confidence interval (CI) = 1.21-3.65]. In ethnicity-subgroup analysis, we found that in Caucasian group, the expression of p53 gene were stronger in TNBC group (OR = 2.60, 95% CI = 1.21-5.57), but there was no statistical significance in Asian group (OR = 1.69, 95% CI = 0.83-3.45). Conclusion: P53 gene could be an effective predictor and a good therapeutic target for TNBC patients in the future, especially in Caucasian. Further researches focusing on p53 gene would gain a breakthrough in the treatment of TNBC.展开更多
Objective To evaluate the use of titanium mesh reconstruction after sternal tumor resection. Methods From January 2007 to January 2011, 14 patients with sternal tumors were admitted into Peking Union Medical Hospital....Objective To evaluate the use of titanium mesh reconstruction after sternal tumor resection. Methods From January 2007 to January 2011, 14 patients with sternal tumors were admitted into Peking Union Medical Hospital. The clinical characteristics, surgical resection, and technique of reconstruction were reviewed. Results Of the 14 patients, 3 had a metastatic sternal tumor, the primary sites of which were as follows: hepatic carcinoma in one case (metastasis 19 years after operation), breast carcinoma in another case (metastasis 5 years after operation), and renal carcinoma in the other case (found simultaneously). Two patients showed local involvement of the sternum: 1 had thymic carcinoma, and the other had myofibrosarcoma. The remaining 9 patients had primary tumors: 4 were osteochondroma, 3 chondrosarcoma, 1 eosinophilic granuloma, 1 non-Hodgekin's lymphoma. En bloc resection of the sternal tumor was performed in all the 14 patients. The defect was repaired with the titanium mesh adjusted to the shape of the defect and fixed with the stainless steel wire. Eleven patients were followed up for a period from 2 months to 4 years, during which no translocation or broken of the titanium mesh was observed. Conclusions Radical en bloc excision remains the treatment of choice for sternal tumors. Sternum defect reconstruction using titanium mesh as a rigid replacement proves appropriate and effective.展开更多
The traffic equilibrium assignment problem under tradable credit scheme(TCS) in a bi-modal stochastic transportation network is investigated in this paper. To describe traveler’s risk-taking behaviors under uncertain...The traffic equilibrium assignment problem under tradable credit scheme(TCS) in a bi-modal stochastic transportation network is investigated in this paper. To describe traveler’s risk-taking behaviors under uncertainty, the cumulative prospect theory(CPT) is adopted. Travelers are assumed to choose the paths with the minimum perceived generalized path costs, consisting of time prospect value(PV) and monetary cost. At equilibrium with a given TCS, the endogenous reference points and credit price remain constant, and are consistent with the equilibrium flow pattern and the corresponding travel time distributions of road sub-network. To describe such an equilibrium state, the CPT-based stochastic user equilibrium(SUE) conditions can be formulated under TCS. An equivalent variational inequality(VI) model embedding a parameterized fixed point(FP) model is then established, with its properties analyzed theoretically. A heuristic solution algorithm is developed to solve the model, which contains two-layer iterations. The outer iteration is a bisection-based contraction method to find the equilibrium credit price, and the inner iteration is essentially the method of successive averages(MSA) to determine the corresponding CPT-based SUE network flow pattern. Numerical experiments are provided to validate the model and algorithm.展开更多
We develop the theory of multivariate saddlepoint approximations. Our treatment differs from the one in Barndorff-Nielsen and Cox (1979, equation (4.7)) in two aspects: 1) our results are satisfied for random ve...We develop the theory of multivariate saddlepoint approximations. Our treatment differs from the one in Barndorff-Nielsen and Cox (1979, equation (4.7)) in two aspects: 1) our results are satisfied for random vectors that are not necessarily sums of independent and identically distributed random vectors, and 2) we consider that the sample is taken from any distribution, not necessarily a member of the exponential family of densities. We also show the relationship with the corresponding multivariate Edgeworth approximations whose general treatment was developed by Durbin in 1980, emphasizing that the basic assumptions that support the validity of both approaches are essentially similar.展开更多
In this papert we give an approach for detecting one or more outliers inrandomized linear model.The likelihood ratio test statistic and its distributions underthe null hypothesis and the alternative hypothesis are giv...In this papert we give an approach for detecting one or more outliers inrandomized linear model.The likelihood ratio test statistic and its distributions underthe null hypothesis and the alternative hypothesis are given. Furthermore,the robustnessof the test statistic in a certain sense is proved. Finally,the optimality properties of thetest are derived.展开更多
A study of the genetic diversity within four subpopulations of Chimonobambusa rivularis Yi and adaptations to altitude, habitat and related factors in Qionglai City of Sichuan province in China, analyzed by random amp...A study of the genetic diversity within four subpopulations of Chimonobambusa rivularis Yi and adaptations to altitude, habitat and related factors in Qionglai City of Sichuan province in China, analyzed by random amplified polymorphic DNA technique. 22 random primers were selected in the amplification and 375 repetitive loci with 350 polymorphic loci were produced. The total average percentage of amplification loci was 93.3%. The genetic diversity of every subpopulation was medium on (the percentage of amplification loci was 49.33%-66.67%). The genetic diversity of high altitude samples of Zhengtiantai was lower than that of low altitude Wutonggang's. There was no obvious differentiation between two subpopulations of Zhengtiantais. The correlation is very low between altitude and the amplification loci and the genetic distance, Pearson correlation coefficient was 0.431 and 0.488 (P 〈 0.01). Through investigation, the primary cause of heredity multiplicity drops was that the habitat had been destroyed by tourism development and other human disturbance.展开更多
基金The National High Technology Research and Development Program of China (863 Program) (No.2007AA01Z422)the NaturalFoundation of Anhui Provincial Education Department (No.2006KJ041B,KJ2007B073)
文摘Combining the characteristics of peer-to-peer (P2P) and grid, a super-peer selection algorithm--SSABC is presented in the distributed network merging P2P and grid. The algorithm computes nodes capacities using their resource properties provided by a grid monitoring and discovery system, such as available bandwidth, free CPU and idle memory, as well as the number of current connections and online time. when a new node joins the network and the super-peers are all saturated, it should select a new super-peer from the new node or joined nodes with the highest capacity. By theoretical analyses and simulation experiments, it is shown that super-peers selected by capacity can achieve higher query success rates and shorten the average hop count when compared with super-peers selected randomly, and they can also balance the network load when all super-peers are saturated. When the number of total nodes changes, the conclusion is still valid, which explains that the algorithm SSABC is feasible and stable.
文摘Plane detection is a prerequisite for many computer vision tasks. This paper proposes a new method which can automatically detect planes from two projective images. Firstly, we modify Scott’s feature point matching method by post-processing its result with the concept of similarity, and then get the lines matching according to feature points matching based on the approximate invariance of the features’ distribution between two images. Finally, we group all feature points into subsets in terms of their geometric relations with feature lines as initial sets to estimate homography rather than by a random search strategy (like RANSAC) as in most existing methods. The proposed method is especially suitable to detecting planes in man-made scenes. This method is validated on real images.
文摘In order to analyze the failure data from repairable systems, the homogeneous Poisson process (HPP) is usually used. In general, HPP cannot be applied to analyze the entire life cycle of a complex, re-pairable system because the rate of occurrence of failures (ROCOF) of the system changes over time rather than remains stable. However, from a practical point of view, it is always preferred to apply the simplest method to address problems and to obtain useful practical results. Therefore, we attempted to use the HPP model to analyze the failure data from real repairable systems. A graphic method and the Laplace test were also used in the analysis. Results of numerical applications show that the HPP model may be a useful tool for the entire life cycle of repairable systems.
基金Project (No. FEBQ24409102) supported by the Space Technology Innovation Fund, China
文摘The performance in vibration environment of switching apparatus containing mechanical contact is an important element when judging the apparatus’s reliability. A piecewise linear two-degrees-of-freedom mathematical model considering contact loss was built in this work, and the vibration performance of the model under random external Gaussian white noise excitation was investigated by using Monte Carlo simulation in Matlab/Simulink. Simulation showed that the spectral content and statistical characters of the contact force coincided strongly with reality. The random vibration character of the contact system was solved using time (numerical) domain simulation in this paper. Conclusions reached here are of great importance for reliability design of switching apparatus.
基金Supported by the National 863 Program of China (No.2006AA12Z325) and the National Natural Science Foundation of China (No.40274005).
文摘To obtain higher accurate position estimates, the stochastic model is estimated by using residual of observations, hence, the stochastic model describes the noise and bias in measurements more realistically. By using GPS data and broadcast ephemeris, the numerical results indicating the accurate position estimates at sub-meter level are obtainable.
基金Under the auspices of National Science & Technology Support Program of China(No.2006BAD20B00)
文摘Grassland fire is one of the most important disturbance factors in the natural ecosystems.This paper focuses on the spatial distribution of long-term grassland fire patterns in the Hulun Buir Grassland located in the northeast of Inner Mongolia Autonomous Region in China.The density or ratio of ignition can reflect the relationship between grassland fire and different ignition factors.Based on the relationship between the density or ratio of ignition in different range of each ignition factor and grassland fire events,an ignition probability model was developed by using binary logistic regression function and its overall accuracy averaged up to 81.7%.Meanwhile it was found that daily relative humidity,daily temperature,elevation,vegetation type,distance to county-level road,distance to town are more important determinants of spatial distribution of fire ignitions.Using Monte Carlo method,we developed a time-dependent stochastic ignition probability model based on the distribution of inter-annual daily relative humidity and daily temperature.Through this model,it is possible to estimate the spatial patterns of ignition probability for grassland fire,which will be helpful to the quantitative evaluation of grassland fire risk and its management in the future.
基金Supported by the Military Major Project for Clinical High-tech and Innovative Technology of China(2010gxjs057)the Municipal Hospitals' Project for Emerging and Frontier Technology of Shanghai(SHDC12010115)the Project for the Key Discipline of Shanghai
文摘Objective:Nephron-sparing surgery(NSS) for small renal masses offers a similar functional and oncological outcome to that of radical surgery.Laparoendoscopic single-site surgery(LESS) emerges as an advanced alternative for reduced invasiveness and improves cosmesis;LESS is developing quickly and its indications have been expanded,but still in its infancy.The aim of this paper is to report our preliminary experience in transumbilical LESS partial nephrectomy(LESS-PN),so as to assess its utility, safety and efficacy.Methods:From August 2009 to October 2010,3 patients underwent transumbilical LESS-PN via a novel multi-channel TriPort by a single experienced urologist in our institution.Patient demographics,perioperative and follow-up data were prospectively collected and analyzed.Results:All the three procedures were successfully completed.A 5-mm ancillary trocar was utilized in all 3 cases.The mean operative duration was 226.3(210-254 min) with an estimated blood loss of 56.7 ml (20-100 ml).Mean warm ischemia time was 35.7 min(19-48 min).One patient was transfused due to postoperative bleeding. The recovery was uneventful and mean length of postoperative stay was 13 days(12-14 days).At the latest follow-up,all patients remained symptom-free and had normal renal function without evidence of recurrence,and they were delighted for a hidden transumbilical scar.Conclusion:Transumbilical LESS-PN is a feasible and safe procedure albeit extremely technically challenging.Surgical outcomes at a median follow-up of 2 years are promising,while currently it should be reserved for highly selected patients with favorable tumor anatomy and performed by a very experienced laparoscopic surgeon.
文摘Banking institutions all over the world face significant challenge due to the cumulative loss due to defaults of borrowers of different types of loans. The cumulative default loss built up over a period of time could wipe out the capital cushion of the banks. The aim of this paper is to help the banks to forecast the cumulative loss and its volatility. Defaulting amounts are random and defaults occur at random instants of time. A non Markovian time dependent random point process is used to model the cumulative loss. The expected loss and volatility are evaluated analytically. They are functions of probability of default, probability of loss amount, recovery rate and time. Probability of default being the important contributor is evaluated using Hidden Markov modeling. Numerical results obtained validate the model.
文摘Suppose {X,X n,n≥1} are the i.i.d. random variables with values in 2 type Banach space B,S n=∑nk=1X k,φ(x) is a increasing function on [0,+∞), φ(x)→+∞, and φ(x)x is no increasing; then we point out that the cluster set CS n2nφ(n) is ρK, where ρ= lim L 2nφ(n)<+∞, ∫ ∞e -ρ 2φ(x) 1xd x=+∞,X∈WM 2 0, and E‖X‖ 2φ(‖X‖)<+∞.
基金Supported by the National Natural Science Foundation of China ( No. 60674009, 60830001 ).
文摘This paper addresses the available capacity and robust connectivity of time division duplex based wireless mesh networks (TDD-based WMNs). A stochastic model is presented for TDD-based WMNs. Considering the parameters that affect the network performance like ratio of control slots number to data slots number, collision probability, node density and average hopcounts, the availa- ble capacity for each node is inferred. Meanwhile, the order of transmission range for robust connec- tivity of large scale WMNs is derived. With the stochastic model and inferred available capacity per node, the performance of TDD-based WMNs using IEEE 802.16 standard is analyzed under various conditions. Simulation results indicate that the available capacity of IEEE 802.16-based TDD-based WMNs and the theoretical result have the same increasing and decreasing trend as the node density increases. Simulation results also illustrate the optimal value of the ratio of control slots number to data slots number that maximizes the available capacity.
基金Projects(51007047,51077087)supported by the National Natural Science Foundation of ChinaProject(2013CB228205)supported by the National Key Basic Research Program of China+1 种基金Project(20100131120039)supported by Higher Learning Doctor Discipline End Scientific Research Fund of the Ministry of Education Institution,ChinaProject(ZR2010EQ035)supported by the Natural Science Foundation of Shandong Province,China
文摘A novel approach was proposed to allocate spinning reserve for dynamic economic dispatch.The proposed approach set up a two-stage stochastic programming model to allocate reserve.The model was solved using a decomposed algorithm based on Benders' decomposition.The model and the algorithm were applied to a simple 3-node system and an actual 445-node system for verification,respectively.Test results show that the model can save 84.5 US $ cost for the testing three-node system,and the algorithm can solve the model for 445-node system within 5 min.The test results also illustrate that the proposed approach is efficient and suitable for large system calculation.
基金supported by a grant from the Key Project of National 12th Five-Years Research Program of China (No. 2012ZX-09303016-002)
文摘Objective: The aim of this study was to explore the relationship between p53 gene and triple-negative breast cancer (TNBC), and determine that whether p53 gene could be a new effective therapeutic target. Methods: We identified studies with quantitative data on the relation of p53 gene and TNBC through searching 12 databases online (Oct. 1999-Oct. 2012) and reviewing the references, which were written in English or Chinese. Summary estimates of odds ratio (OR) was calculated using the fixed-effects model or the random-effects model as appropriate. Results: We identified 12 eligible stud- ies with 1532 cases of TNBC patients and 6329 controls of non-TNBC patients. The test for homogeneity resulted in X^2 = 200.16 (P 〈 0.05), it showed significant heterogeneity so that a random effect model was applied. Our results showed that the expression of p53 gene could be much stronger in TNBC group than that in non-TNBC group [OR = 2.10, 95% confidence interval (CI) = 1.21-3.65]. In ethnicity-subgroup analysis, we found that in Caucasian group, the expression of p53 gene were stronger in TNBC group (OR = 2.60, 95% CI = 1.21-5.57), but there was no statistical significance in Asian group (OR = 1.69, 95% CI = 0.83-3.45). Conclusion: P53 gene could be an effective predictor and a good therapeutic target for TNBC patients in the future, especially in Caucasian. Further researches focusing on p53 gene would gain a breakthrough in the treatment of TNBC.
文摘Objective To evaluate the use of titanium mesh reconstruction after sternal tumor resection. Methods From January 2007 to January 2011, 14 patients with sternal tumors were admitted into Peking Union Medical Hospital. The clinical characteristics, surgical resection, and technique of reconstruction were reviewed. Results Of the 14 patients, 3 had a metastatic sternal tumor, the primary sites of which were as follows: hepatic carcinoma in one case (metastasis 19 years after operation), breast carcinoma in another case (metastasis 5 years after operation), and renal carcinoma in the other case (found simultaneously). Two patients showed local involvement of the sternum: 1 had thymic carcinoma, and the other had myofibrosarcoma. The remaining 9 patients had primary tumors: 4 were osteochondroma, 3 chondrosarcoma, 1 eosinophilic granuloma, 1 non-Hodgekin's lymphoma. En bloc resection of the sternal tumor was performed in all the 14 patients. The defect was repaired with the titanium mesh adjusted to the shape of the defect and fixed with the stainless steel wire. Eleven patients were followed up for a period from 2 months to 4 years, during which no translocation or broken of the titanium mesh was observed. Conclusions Radical en bloc excision remains the treatment of choice for sternal tumors. Sternum defect reconstruction using titanium mesh as a rigid replacement proves appropriate and effective.
基金Project(BX20180268)supported by National Postdoctoral Program for Innovative Talent,ChinaProject(300102228101)supported by Fundamental Research Funds for the Central Universities of China+1 种基金Project(51578150)supported by the National Natural Science Foundation of ChinaProject(18YJCZH130)supported by the Humanities and Social Science Project of Chinese Ministry of Education
文摘The traffic equilibrium assignment problem under tradable credit scheme(TCS) in a bi-modal stochastic transportation network is investigated in this paper. To describe traveler’s risk-taking behaviors under uncertainty, the cumulative prospect theory(CPT) is adopted. Travelers are assumed to choose the paths with the minimum perceived generalized path costs, consisting of time prospect value(PV) and monetary cost. At equilibrium with a given TCS, the endogenous reference points and credit price remain constant, and are consistent with the equilibrium flow pattern and the corresponding travel time distributions of road sub-network. To describe such an equilibrium state, the CPT-based stochastic user equilibrium(SUE) conditions can be formulated under TCS. An equivalent variational inequality(VI) model embedding a parameterized fixed point(FP) model is then established, with its properties analyzed theoretically. A heuristic solution algorithm is developed to solve the model, which contains two-layer iterations. The outer iteration is a bisection-based contraction method to find the equilibrium credit price, and the inner iteration is essentially the method of successive averages(MSA) to determine the corresponding CPT-based SUE network flow pattern. Numerical experiments are provided to validate the model and algorithm.
文摘We develop the theory of multivariate saddlepoint approximations. Our treatment differs from the one in Barndorff-Nielsen and Cox (1979, equation (4.7)) in two aspects: 1) our results are satisfied for random vectors that are not necessarily sums of independent and identically distributed random vectors, and 2) we consider that the sample is taken from any distribution, not necessarily a member of the exponential family of densities. We also show the relationship with the corresponding multivariate Edgeworth approximations whose general treatment was developed by Durbin in 1980, emphasizing that the basic assumptions that support the validity of both approaches are essentially similar.
文摘In this papert we give an approach for detecting one or more outliers inrandomized linear model.The likelihood ratio test statistic and its distributions underthe null hypothesis and the alternative hypothesis are given. Furthermore,the robustnessof the test statistic in a certain sense is proved. Finally,the optimality properties of thetest are derived.
文摘A study of the genetic diversity within four subpopulations of Chimonobambusa rivularis Yi and adaptations to altitude, habitat and related factors in Qionglai City of Sichuan province in China, analyzed by random amplified polymorphic DNA technique. 22 random primers were selected in the amplification and 375 repetitive loci with 350 polymorphic loci were produced. The total average percentage of amplification loci was 93.3%. The genetic diversity of every subpopulation was medium on (the percentage of amplification loci was 49.33%-66.67%). The genetic diversity of high altitude samples of Zhengtiantai was lower than that of low altitude Wutonggang's. There was no obvious differentiation between two subpopulations of Zhengtiantais. The correlation is very low between altitude and the amplification loci and the genetic distance, Pearson correlation coefficient was 0.431 and 0.488 (P 〈 0.01). Through investigation, the primary cause of heredity multiplicity drops was that the habitat had been destroyed by tourism development and other human disturbance.