In May of 2007,the second generation selected （SS） and control （SC） groups of pearl oyster Pinctada martensii were established by selecting 10% breeders with the largest and mean shell length,respectively,from the...In May of 2007,the second generation selected （SS） and control （SC） groups of pearl oyster Pinctada martensii were established by selecting 10% breeders with the largest and mean shell length,respectively,from the first generation selected group.Growth performance of the SS and SC groups were compared on the basis of measurement data at Days 8,18,60,95,195 and 365.On Day 365,100 individuals （60.0–75.0 mm at shell length） were sampled from each group and then subjected to the experiment where physiological parameters such as filtrate rate,oxygen consumption and ammonia excretion were measured at 15,20,25 and 30°C.The results show that the SS group had significantly larger mean shell length and shell height than the SC group at Days 8,18,60,95,195 and 365 （P 0.05）.The genetic gains at different ages varied from 6.0% to 17.0% for shell length and 5.7% to 14.6% for shell height,respectively.At 15,20,25 and 30 ° C,the SS groups had significantly larger filtrate rate than the SC group （P 0.05）.At 15 and 25 °C,the differences in oxygen consumption rate between the SS and SC groups were not significant （P 0.05）.At 20 and 30 °C,however,the oxygen consumption rate of the SS group was significantly larger than the SC group （P 0.05）.At 15,20,25 and 30 °C,there were no significant differences in ammonia excretion rate between the SS and SC groups （P 0.05）.The present results indicate that there existed considerable genetic variability in the base population and a further selection could be likely fruitful.Mass selection for faster growth might produce animals that had higher intake of metabolizable energy by virtue of faster filtrating behavior.展开更多
The decisions concerning portfolio selection for army engineering and manufacturing development projects determine the benefit of those projects to the country concerned.Projects are typically selected based on ex ant...The decisions concerning portfolio selection for army engineering and manufacturing development projects determine the benefit of those projects to the country concerned.Projects are typically selected based on ex ante estimates of future return values,which are usually difficult to specify or only generated after project launch.A scenario-based approach is presented here to address the problem of selecting a project portfolio under incomplete scenario information and interdependency constraints.In the first stage,the relevant dominance concepts of scenario analysis are studied to handle the incomplete information.Then,a scenario-based programming approach is proposed to handle the interdependencies to obtain the projects,whose return values are multi-criteria with interval data.Finally,an illustrative example of army engineering and manufacturing development shows the feasibility and advantages of the scenario-based multi-objective programming approach.展开更多
Effects of copper toxicity and salinity shock on selective group of juvenile pompano Trachinotus ovatus were investigated.The fish were exposed to different Cu2+ concentrations of 0(blank),0.02(C1),0.05(C2),0.10(C3),a...Effects of copper toxicity and salinity shock on selective group of juvenile pompano Trachinotus ovatus were investigated.The fish were exposed to different Cu2+ concentrations of 0(blank),0.02(C1),0.05(C2),0.10(C3),and 0.15 mg·L–1(C4)at a salinity of 10‰ or 40‰ for 96 h,with the salinity of 29‰ as the control.The results showed that the effects of the acute salinity stimulation to survival rates of pompano between control(29‰)and lower or higher salinity for 96 h were not significant(p>0.05).However,the survival rates in each treatment were decreased with the increase of Cu2+ concentration.The dominant factor influencing body moisture of the fish was salinity,and there was no sign that body moisture was correlated with exposure to Cu2+.The gill lamellas in high level of Cu2+ concentration(C4 treatments)were abnormal under the salinity of 40‰ and extremely curly under the salinity of 10‰.Hemorrhage in gill was observed in the two C4 treatments.Under transmission electron microscope,pillar cells in gill lamellas appeared deformed and ruptured in some areas of the epithelia in the higher concentration of Cu2+,resulting in the death of the fish due to the destruction of gill tissue,elevation of the arithmetic mean distance from water to blood,the decrease of oxygen diffusion capacity,and other physiological functions.These findings indicate that the pompano might suffer much more pressure when encountered with Cu2+ pollution and low salinity.展开更多
The paper posits that kin sociality and eusociality are derived from the handicap-care principles based on the need-based care to the handicappers from the caregivers for the self-interest of the caregivers. In this p...The paper posits that kin sociality and eusociality are derived from the handicap-care principles based on the need-based care to the handicappers from the caregivers for the self-interest of the caregivers. In this paper, handicap is defined as the difficulty to survive and reproduce independently. Kin sociality is derived from the childhood handicap-care principle where the children are the handicapped children who receive the care from the kin caregivers in the inclusive kin group to survive. The caregiver gives care for its self-interest to reproduce its gene. The individual’s gene of kin sociality contains the handicapped childhood and the caregiving adulthood. Eusociality is derived from the adulthood handicap-care principle where responsible adults are the handicapped adults who give care and receive care at the same time in the interdependent eusocial group to survive and reproduce its gene. Queen bees reproduce, but must receive care from worker bees that work but must rely on queen bees to reproduce. A caregiver gives care for its self-interest to survive and reproduce its gene. The individual’s gene of eusociality contains the handicapped childhood-adulthood and the caregiving adulthood. The chronological sequence of the sociality evolution is individual sociality without handicap, kin sociality with handicapped childhood, and eusociality with handicapped adulthood. Eusociality in humans is derived from bipedalism and the mixed habitat. The chronological sequence of the eusocial human evolution is 1) the eusocial early hominins with bipedalism and the mixed habitat, 2) the eusocial early Homo species with bipedalism, the larger brain, and the open habitat, 3) the eusocial late Homo species with bipedalism, the largest brain, and the unstable habitat, and 4) extended eusocial Homo sapiens with bipedalism, the shrinking brain, omnipresent imagination, and the harsh habitat. The omnipresence of imagination in human culture converts eusociality into extended eusociality with both perception and omnipresent imagination.展开更多
When selection increases the frequency of a beneficial gene substitution it can also increase the frequencies of linked neutral alleles through a process called genetic hitchhiking. A model built to investigate reduce...When selection increases the frequency of a beneficial gene substitution it can also increase the frequencies of linked neutral alleles through a process called genetic hitchhiking. A model built to investigate reduced genetic diversity in Pleistocene hominins shows that genetic hitchhiking can have a strong effect on neutral diversity in the presence of culturally mediated mi- gration. Under conditions in which genetic and cultural variants are transmitted symmetrically, neutral genes may also hitchhike to higher frequencies on the coattails of adaptive cultural traits through a process called cultural hitchhiking. Cultural hitchhiking has been proposed to explain why some species of matrilineal whales display relatively low levels of mitochondrial DNA diver- sity, and it may be applicable to humans as well. This paper provides a critical review of recent models of both types of hitch- hiking in socially structured populations. The models＇ assumptions and predictions are compared and discussed in the hope that studies of reduced genetic diversity in humans might improve our understanding of reduced genetic diversity in other species, and vice versa展开更多
Time and motion studies were conducted to evaluate the impact of selective cutting type on Chainsaw productivity in Caspian forests, the selective cutting performed as single and group selection cutting in the region....Time and motion studies were conducted to evaluate the impact of selective cutting type on Chainsaw productivity in Caspian forests, the selective cutting performed as single and group selection cutting in the region. The selective cutting was performed on a 42-ha tract with an average slope of 30%. The results indicate that felling time for per tree is most affected by diameter at breast height, the distance among harvested trees in single-tree selection method and diameter at breast height in group selection method. The production rate in single and group selection cutting were 21.2 m^3·h^-1 and 28.4 m^3·h^-1 for one person, respectively. Considering the gross and net production rate in single and group selection cutting, the unit cost was 1.11 USD.m^-3 and 0.88 USD.m^-3, respectively. The results indicate that group selection cutting can be more profitable than single-tree selection method.展开更多
In practice, predictors possess grouping structures spontaneously. Incorporation of such useful information can improve statistical modeling and inference. In addition, the high-dimensionality often leads to the colli...In practice, predictors possess grouping structures spontaneously. Incorporation of such useful information can improve statistical modeling and inference. In addition, the high-dimensionality often leads to the collinearity problem. The elastic net is an ideal method which is inclined to reflect a grouping effect. In this paper, we consider the problem of group selection and estimation in the sparse linear regression model in which predictors can be grouped. We investigate a group adaptive elastic-net and derive oracle inequalities and model consistency for the cases where group number is larger than the sample size. Oracle property is addressed for the case of the fixed group number. We revise the locally approximated coordinate descent algorithm to make our computation. Simulation and real data studies indicate that the group adaptive elastic-net is an alternative and competitive method for model selection of high-dimensional problems for the cases of group number being larger than the sample size.展开更多
The planetary roller screw mechanism(PRSM)is a novel precision transmission mechanism that realizes the conversion between linear and rotary motions.The contact characteristics of helical surfaces directly determine P...The planetary roller screw mechanism(PRSM)is a novel precision transmission mechanism that realizes the conversion between linear and rotary motions.The contact characteristics of helical surfaces directly determine PRSM’s performance in load-carrying capacity and transmission accuracy.Therefore,studying the contact characteristics of PRSM forms the fundamental basis for enhancing its transmission performance.In this study,a three-dimensional parametric analysis method of contact characteristics is proposed based on the PRSM meshing principle and PyVista(a high-level API to the Visualization Toolkit).The proposed method considers the influence of machining errors among various thread teeth.The effects of key machining errors on contact positions and axial clearance,as well as their sensitivities,are analyzed.With excellent solution accuracy,this method exhibits higher calculation efficiency and stronger robustness than the analytical and numerical meshing models.The influence of nominal diameter and pitch errors of the screw,roller,and nut on the axial clearance follows a linear relationship,whereas flank angle errors have negligible effects on the axial clearance.The corresponding influence coefficients for these three machining errors on the axial clearance are 0.623,0.341,and 0.036.The variations in contact positions caused by individual errors are axisymmetric.Flank angle errors and roller diameter errors result in linear displacements of the contact points,whereas pitch errors cause the contact points to move along the arc of the roller diameter.Based on the proposed threedimensional parametric contact characteristics analysis method,the Fuzzy C-Means clustering algorithm considering error sensitivity is utilized to establish a component grouping technique in the selective assembly of critical PRSM components,ensuring the rational and consistent clearances based on the given component’s machining errors.This study provides effective guidance for analyzing contact characteristics and grouping in selective assembly for PRSM components.It also presents the proposed method’s potential applicability to similar calculation problems for contact positions and clearances in other transmission systems.展开更多
According to the information coming from concerned depart-ment, the total production of auto would be 1.67 million units in 1999, including 530,000 cars. You can read programs set by selected auto groups below for det...According to the information coming from concerned depart-ment, the total production of auto would be 1.67 million units in 1999, including 530,000 cars. You can read programs set by selected auto groups below for details: FAW Group ◆Production and sales: 300 thousand units. ◆Products: widen the展开更多
In many applications,covariates can be naturally grouped.For example,for gene expression data analysis,genes belonging to the same pathway might be viewed as a group.This paper studies variable selection problem for c...In many applications,covariates can be naturally grouped.For example,for gene expression data analysis,genes belonging to the same pathway might be viewed as a group.This paper studies variable selection problem for censored survival data in the additive hazards model when covariates are grouped.A hierarchical regularization method is proposed to simultaneously estimate parameters and select important variables at both the group level and the within-group level.For the situations in which the number of parameters tends to∞as the sample size increases,we establish an oracle property and asymptotic normality property of the proposed estimators.Numerical results indicate that the hierarchically penalized method performs better than some existing methods such as lasso,smoothly clipped absolute deviation(SCAD)and adaptive lasso.展开更多
基金The National Key Technology R&D Program in the 11th Five Year Plan of China under contract No. 2007BAD29B01-2National Department Public Benefit Research Foundation under contract No. nyhyzx 07-048Guangdong Marine and Fishery Bureau under contract Nos A200708C01, A200908A02 and A200908A05
文摘In May of 2007,the second generation selected （SS） and control （SC） groups of pearl oyster Pinctada martensii were established by selecting 10% breeders with the largest and mean shell length,respectively,from the first generation selected group.Growth performance of the SS and SC groups were compared on the basis of measurement data at Days 8,18,60,95,195 and 365.On Day 365,100 individuals （60.0–75.0 mm at shell length） were sampled from each group and then subjected to the experiment where physiological parameters such as filtrate rate,oxygen consumption and ammonia excretion were measured at 15,20,25 and 30°C.The results show that the SS group had significantly larger mean shell length and shell height than the SC group at Days 8,18,60,95,195 and 365 （P 0.05）.The genetic gains at different ages varied from 6.0% to 17.0% for shell length and 5.7% to 14.6% for shell height,respectively.At 15,20,25 and 30 ° C,the SS groups had significantly larger filtrate rate than the SC group （P 0.05）.At 15 and 25 °C,the differences in oxygen consumption rate between the SS and SC groups were not significant （P 0.05）.At 20 and 30 °C,however,the oxygen consumption rate of the SS group was significantly larger than the SC group （P 0.05）.At 15,20,25 and 30 °C,there were no significant differences in ammonia excretion rate between the SS and SC groups （P 0.05）.The present results indicate that there existed considerable genetic variability in the base population and a further selection could be likely fruitful.Mass selection for faster growth might produce animals that had higher intake of metabolizable energy by virtue of faster filtrating behavior.
基金supported by the National Natural Science Foundation of China(7157118571201168)
文摘The decisions concerning portfolio selection for army engineering and manufacturing development projects determine the benefit of those projects to the country concerned.Projects are typically selected based on ex ante estimates of future return values,which are usually difficult to specify or only generated after project launch.A scenario-based approach is presented here to address the problem of selecting a project portfolio under incomplete scenario information and interdependency constraints.In the first stage,the relevant dominance concepts of scenario analysis are studied to handle the incomplete information.Then,a scenario-based programming approach is proposed to handle the interdependencies to obtain the projects,whose return values are multi-criteria with interval data.Finally,an illustrative example of army engineering and manufacturing development shows the feasibility and advantages of the scenario-based multi-objective programming approach.
基金supported by Special Scientific Research Funds for Central Non-profit Institutes,Chinese Academy of Fishery Sciences(2012A0401,2013A0501)
文摘Effects of copper toxicity and salinity shock on selective group of juvenile pompano Trachinotus ovatus were investigated.The fish were exposed to different Cu2+ concentrations of 0(blank),0.02(C1),0.05(C2),0.10(C3),and 0.15 mg·L–1(C4)at a salinity of 10‰ or 40‰ for 96 h,with the salinity of 29‰ as the control.The results showed that the effects of the acute salinity stimulation to survival rates of pompano between control(29‰)and lower or higher salinity for 96 h were not significant(p>0.05).However,the survival rates in each treatment were decreased with the increase of Cu2+ concentration.The dominant factor influencing body moisture of the fish was salinity,and there was no sign that body moisture was correlated with exposure to Cu2+.The gill lamellas in high level of Cu2+ concentration(C4 treatments)were abnormal under the salinity of 40‰ and extremely curly under the salinity of 10‰.Hemorrhage in gill was observed in the two C4 treatments.Under transmission electron microscope,pillar cells in gill lamellas appeared deformed and ruptured in some areas of the epithelia in the higher concentration of Cu2+,resulting in the death of the fish due to the destruction of gill tissue,elevation of the arithmetic mean distance from water to blood,the decrease of oxygen diffusion capacity,and other physiological functions.These findings indicate that the pompano might suffer much more pressure when encountered with Cu2+ pollution and low salinity.
文摘The paper posits that kin sociality and eusociality are derived from the handicap-care principles based on the need-based care to the handicappers from the caregivers for the self-interest of the caregivers. In this paper, handicap is defined as the difficulty to survive and reproduce independently. Kin sociality is derived from the childhood handicap-care principle where the children are the handicapped children who receive the care from the kin caregivers in the inclusive kin group to survive. The caregiver gives care for its self-interest to reproduce its gene. The individual’s gene of kin sociality contains the handicapped childhood and the caregiving adulthood. Eusociality is derived from the adulthood handicap-care principle where responsible adults are the handicapped adults who give care and receive care at the same time in the interdependent eusocial group to survive and reproduce its gene. Queen bees reproduce, but must receive care from worker bees that work but must rely on queen bees to reproduce. A caregiver gives care for its self-interest to survive and reproduce its gene. The individual’s gene of eusociality contains the handicapped childhood-adulthood and the caregiving adulthood. The chronological sequence of the sociality evolution is individual sociality without handicap, kin sociality with handicapped childhood, and eusociality with handicapped adulthood. Eusociality in humans is derived from bipedalism and the mixed habitat. The chronological sequence of the eusocial human evolution is 1) the eusocial early hominins with bipedalism and the mixed habitat, 2) the eusocial early Homo species with bipedalism, the larger brain, and the open habitat, 3) the eusocial late Homo species with bipedalism, the largest brain, and the unstable habitat, and 4) extended eusocial Homo sapiens with bipedalism, the shrinking brain, omnipresent imagination, and the harsh habitat. The omnipresence of imagination in human culture converts eusociality into extended eusociality with both perception and omnipresent imagination.
文摘When selection increases the frequency of a beneficial gene substitution it can also increase the frequencies of linked neutral alleles through a process called genetic hitchhiking. A model built to investigate reduced genetic diversity in Pleistocene hominins shows that genetic hitchhiking can have a strong effect on neutral diversity in the presence of culturally mediated mi- gration. Under conditions in which genetic and cultural variants are transmitted symmetrically, neutral genes may also hitchhike to higher frequencies on the coattails of adaptive cultural traits through a process called cultural hitchhiking. Cultural hitchhiking has been proposed to explain why some species of matrilineal whales display relatively low levels of mitochondrial DNA diver- sity, and it may be applicable to humans as well. This paper provides a critical review of recent models of both types of hitch- hiking in socially structured populations. The models＇ assumptions and predictions are compared and discussed in the hope that studies of reduced genetic diversity in humans might improve our understanding of reduced genetic diversity in other species, and vice versa
文摘Time and motion studies were conducted to evaluate the impact of selective cutting type on Chainsaw productivity in Caspian forests, the selective cutting performed as single and group selection cutting in the region. The selective cutting was performed on a 42-ha tract with an average slope of 30%. The results indicate that felling time for per tree is most affected by diameter at breast height, the distance among harvested trees in single-tree selection method and diameter at breast height in group selection method. The production rate in single and group selection cutting were 21.2 m^3·h^-1 and 28.4 m^3·h^-1 for one person, respectively. Considering the gross and net production rate in single and group selection cutting, the unit cost was 1.11 USD.m^-3 and 0.88 USD.m^-3, respectively. The results indicate that group selection cutting can be more profitable than single-tree selection method.
基金supported by National Natural Science Foundation of China(Grant No.11571219)the Open Research Fund Program of Key Laboratory of Mathematical Economics(SUFE)(Grant No.201309KF02)Ministry of Education,and Changjiang Scholars and Innovative Research Team in University(Grant No.IRT13077)
文摘In practice, predictors possess grouping structures spontaneously. Incorporation of such useful information can improve statistical modeling and inference. In addition, the high-dimensionality often leads to the collinearity problem. The elastic net is an ideal method which is inclined to reflect a grouping effect. In this paper, we consider the problem of group selection and estimation in the sparse linear regression model in which predictors can be grouped. We investigate a group adaptive elastic-net and derive oracle inequalities and model consistency for the cases where group number is larger than the sample size. Oracle property is addressed for the case of the fixed group number. We revise the locally approximated coordinate descent algorithm to make our computation. Simulation and real data studies indicate that the group adaptive elastic-net is an alternative and competitive method for model selection of high-dimensional problems for the cases of group number being larger than the sample size.
基金supported by the National Key R&D Program of China(Grant No.2023YFB3406404).
文摘The planetary roller screw mechanism(PRSM)is a novel precision transmission mechanism that realizes the conversion between linear and rotary motions.The contact characteristics of helical surfaces directly determine PRSM’s performance in load-carrying capacity and transmission accuracy.Therefore,studying the contact characteristics of PRSM forms the fundamental basis for enhancing its transmission performance.In this study,a three-dimensional parametric analysis method of contact characteristics is proposed based on the PRSM meshing principle and PyVista(a high-level API to the Visualization Toolkit).The proposed method considers the influence of machining errors among various thread teeth.The effects of key machining errors on contact positions and axial clearance,as well as their sensitivities,are analyzed.With excellent solution accuracy,this method exhibits higher calculation efficiency and stronger robustness than the analytical and numerical meshing models.The influence of nominal diameter and pitch errors of the screw,roller,and nut on the axial clearance follows a linear relationship,whereas flank angle errors have negligible effects on the axial clearance.The corresponding influence coefficients for these three machining errors on the axial clearance are 0.623,0.341,and 0.036.The variations in contact positions caused by individual errors are axisymmetric.Flank angle errors and roller diameter errors result in linear displacements of the contact points,whereas pitch errors cause the contact points to move along the arc of the roller diameter.Based on the proposed threedimensional parametric contact characteristics analysis method,the Fuzzy C-Means clustering algorithm considering error sensitivity is utilized to establish a component grouping technique in the selective assembly of critical PRSM components,ensuring the rational and consistent clearances based on the given component’s machining errors.This study provides effective guidance for analyzing contact characteristics and grouping in selective assembly for PRSM components.It also presents the proposed method’s potential applicability to similar calculation problems for contact positions and clearances in other transmission systems.
文摘According to the information coming from concerned depart-ment, the total production of auto would be 1.67 million units in 1999, including 530,000 cars. You can read programs set by selected auto groups below for details: FAW Group ◆Production and sales: 300 thousand units. ◆Products: widen the
基金supported by National Natural Science Foundation of China(Grant Nos.11171112,11101114 and 11201190)National Statistical Science Research Major Program of China(Grant No.2011LZ051)
文摘In many applications,covariates can be naturally grouped.For example,for gene expression data analysis,genes belonging to the same pathway might be viewed as a group.This paper studies variable selection problem for censored survival data in the additive hazards model when covariates are grouped.A hierarchical regularization method is proposed to simultaneously estimate parameters and select important variables at both the group level and the within-group level.For the situations in which the number of parameters tends to∞as the sample size increases,we establish an oracle property and asymptotic normality property of the proposed estimators.Numerical results indicate that the hierarchically penalized method performs better than some existing methods such as lasso,smoothly clipped absolute deviation(SCAD)and adaptive lasso.
