Under the background of a severe job market and fierce talent competition,the career planning education of college students is of great importance.In this study,a combination of quantitative and qualitative research m...Under the background of a severe job market and fierce talent competition,the career planning education of college students is of great importance.In this study,a combination of quantitative and qualitative research methods was used;500 students in Shenzhen Polytechnic of Information Technology were surveyed by questionnaire,and 40 counselors were interviewed in depth to comprehensively analyze the role and practical effect of counselors in career planning education.The research showed that the role positioning of counselors includes the guide of students’career development,emotional support,and job-hunting strategy,and the specific path selection involves the strengthening of professional knowledge,the construction of interpersonal relationship networks,and personalized counseling.Based on the survey and interview data,this paper constructed a model for enhancing the role of counselors in career planning education and put forward a set of targeted work paths.展开更多
Flexible strain sensors are promising in sensing minuscule mechanical signals,and thereby widely used in various advanced fields.However,the effective integration of hypersensitivity and highly selective response into...Flexible strain sensors are promising in sensing minuscule mechanical signals,and thereby widely used in various advanced fields.However,the effective integration of hypersensitivity and highly selective response into one flexible strain sensor remains a huge challenge.Herein,inspired by the hysteresis strategy of the scorpion slit receptor,a bio-inspired flexible strain sensor(BFSS)with parallel through-slit arrays is designed and fabricated.Specifically,BFSS consists of conductive monolayer graphene and viscoelastic styrene–isoprene–styrene block copolymer.Under the synergistic effect of the bio-inspired slit structures and flexible viscoelastic materials,BFSS can achieve both hypersensitivity and highly selective frequency response.Remarkably,the BFSS exhibits a high gage factor of 657.36,and a precise identification of vibration frequencies at a resolution of 0.2 Hz through undergoing different morphological changes to high-frequency vibration and low-frequency vibration.Moreover,the BFSS possesses a wide frequency detection range(103 Hz)and stable durability(1000 cycles).It can sense and recognize vibration signals with different characteristics,including the frequency,amplitude,and waveform.This work,which turns the hysteresis effect into a"treasure,"can provide new design ideas for sensors for potential applications including human–computer interaction and health monitoring of mechanical equipment.展开更多
Larix gmelinii var.principis-rupprechtii(Mayr.)Pilger is an important native tree species in North China with advantages of fast growth,straight trunk,and good wood properties.The multi-year and multi-site breeding re...Larix gmelinii var.principis-rupprechtii(Mayr.)Pilger is an important native tree species in North China with advantages of fast growth,straight trunk,and good wood properties.The multi-year and multi-site breeding research of families of the species has not been reported previously.Based on diameter at breast height(DBH),height and volume of 25 families on four experimental sites,we calculated variance components,genetic parameters,juvenile and mature trait correlations and made genotype main effect plus genotype×environment interaction effect(GGE)biplot based on the breeding values estimated using the method of best linear unbiased prediction(BLUP).Compared with height,DBH and volume had higher heritability and larger variation coefficients,making them the more suitable traits for family selection and evaluation.Based on these,GGE biplots containing 20 combinations of site×age were drawn using data at 13 to 17 years when the interactions between family and location were strong.Test sites classifications based on DBH,and volume were inconsistent,with two categories for DBH and one for volume.The Guyuan site was the most suitable with strong discriminating ability,high representativeness and stability among tree ages.Integrating the ranking results of DBH and volume,families 66,76,82 and 111 were high-yielding and stable,families 78 and96 were high-yielding with above average stability,families72 and 79 were high-yielding with below average stability,whereas stability of family 100 was inconsistent between DBH and volume.Early selection based on DBH was convenient and reliable,and can be made at seven years.This study provides support for the selection of Larix gmelinii var.principis-rupprechtii families in Hebei province and an example for the application of stem analysis data from multiple sites in tree breeding.展开更多
Based on China's industrial enterprises-customs matched data, this paper utilizes two-tier stochastic frontier analysis method to estimate and verify the extent to which selection effect and competition effect inf...Based on China's industrial enterprises-customs matched data, this paper utilizes two-tier stochastic frontier analysis method to estimate and verify the extent to which selection effect and competition effect influence exporting firms' markup. Our findings suggest that the interaction between selection effect and competition effect ultimately causes actual firm markup to be higher than the baseline markup by 7.11%. Exporting firms' actual markup is higher than the baseline markup by different degrees. In terms of the decomposition of selection effect, TFP explains for 28.05% of selection effect, and nonproductivity factors explain for the rest 71.95%. By controlling for the type of firms' export,the export-productivity paradox only exists for processing trade firms, which shows that with increasing trade facilitation, the policy incentives to encourage firms to export are major contributors to the low export markups.展开更多
We consider the problem of variable selection for the single-index random effects models with longitudinal data. An automatic variable selection procedure is developed using smooth-threshold. The proposed method share...We consider the problem of variable selection for the single-index random effects models with longitudinal data. An automatic variable selection procedure is developed using smooth-threshold. The proposed method shares some of the desired features of existing variable selection methods: the resulting estimator enjoys the oracle property;the proposed procedure avoids the convex optimization problem and is flexible and easy to implement. Moreover, we use the penalized weighted deviance criterion for a data-driven choice of the tuning parameters. Simulation studies are carried out to assess the performance of our method, and a real dataset is analyzed for further illustration.展开更多
This paper investigates the development,the breakdown process,and the discharge path selection of the lightning discharges in two-phase mixtures(TPMs).13 kinds of solid-gas mixtures and 3 kinds of liquid-gas mixtures ...This paper investigates the development,the breakdown process,and the discharge path selection of the lightning discharges in two-phase mixtures(TPMs).13 kinds of solid-gas mixtures and 3 kinds of liquid-gas mixtures are employed to study effect of two phase mixtures on the selection of the discharge path under lightning impulses.Grain size effects are shown upon these experimental results.When the diameter of solid or liquid grains is less than about 10 μm,the discharge path does not select TPM but air.And the discharge path selects TPM when the diameter is greater than about 100 μm.And when the diameter is between about 10 μm and 100 μm,the discharge path selects TPM under negative lightning impulses,but it has a greater selection of air than TPMs under positive lightning impulses.Volume fraction and permittivity of solid/liquid can also influence the selection of the discharge path.展开更多
This research develops two new models for project portfolio selection, in which the candidate projects are composed of multiple repetitive units. To reflect some real situations, the learning effect is considered in t...This research develops two new models for project portfolio selection, in which the candidate projects are composed of multiple repetitive units. To reflect some real situations, the learning effect is considered in the project portfolio selection problem for the first time. The mathematical representations of the relationship between learning experience and investment cost are provided. One numerical example under different scenarios is demonstrated and the impact of considering learning effect is then discussed.展开更多
The F2, F3, families and F4 lines of six soybean crosses, were selected successively under high-and low - fertility sites with the relection objective of high yield and the method of pedigree was used. Two best F4 - d...The F2, F3, families and F4 lines of six soybean crosses, were selected successively under high-and low - fertility sites with the relection objective of high yield and the method of pedigree was used. Two best F4 - derived lines were chosen from each of the six crosses under both high-and low-fertility for use in this study. In 1995, the total 24 lines were tested in high, medium and low fertility sites with the same experimental design (CRB) to study the selcctoin effects of high and low - fertility. The results suggested that high- and low-fertility had different selection effects. High fertility was more effective for selecting lines, which had higher yield under high-fertility and lower yield under low-fertility; low-fertility was better for selecting lines, which had higher yield under low-fertility and lower yield under low-fertility, and high fertility was somewhat better than low fertility for selecting lines, which had higher yield under both high and low-fertility. It revealed that the lines selected from high-fertility had superior yield potential. The lines selected from high-fertility had shorter plant height, more nodes on main stem, fewer branches, higher seed-stem ratio. The reverse was true for the lines selected from low-fertility . The lodging-resistance of the lines selected from highfertility was greater than that of the lines from low-fertility. The soil fertility level of breeding nursery should be chosen according to the breeding objective.展开更多
This paper lays particular emphasis on pun's effectiveness and selectivity in English advertisements.The illustration and examples can help us understand the English advertisements well and foster our ability to a...This paper lays particular emphasis on pun's effectiveness and selectivity in English advertisements.The illustration and examples can help us understand the English advertisements well and foster our ability to appreciate the charm of English.展开更多
The green miridbug,Cyrtorhinus lividipennis,is an important predator of the rice brown planthopper,Nilaparvata lugens.In this study,the selective toxicity of seven commercial biopesticides for C.lividipennis was exami...The green miridbug,Cyrtorhinus lividipennis,is an important predator of the rice brown planthopper,Nilaparvata lugens.In this study,the selective toxicity of seven commercial biopesticides for C.lividipennis was examined under laboratory conditions; abamectin was the most selective to C.lividipennis,followed by matrine and azadirachtin.Veratridine,rotenone,Bacillus thuringiensis and Beauveria bassiana showed less selectivity for C.lividipennis.Subsequently,matrine,abamectin and azadirachtin were selected for sublethal assessments with respect to C.lividipennis due to their high toxicities to N.lugens.C.lividipennis treated with sublethal concentrations(LC10 and LC20) of the three biopesticides could distinguish volatiles released from healthy and N.lugens-infested plants indicating that the biopesticides tested did not affect the foraging ability of surviving miridbugs.Azadirachtin decreased the consumption capability of C.lividipennis when the densities of N.lugens were 20,30,40 and 50 insects per vial.Sublethal concentration treatment did not impact the pre-oviposition period or egg hatchability of C.lividipennis.However,the fecundity of C.lividipennis exposed to azadirachtin and abamectin increased by 27–41% compared to the untreated individuals.In summary,abamectin or matrine together with C.lividipennis could be considered an effective,sustainable pest management strategy for rice.展开更多
Objective:To investigate the effects of 20 methanolic extracts from Malaysian selected plants on CD18/11 a expression and phagocytosis activity of leukocytes using flow cytometry analysis.Methods:The effects of methan...Objective:To investigate the effects of 20 methanolic extracts from Malaysian selected plants on CD18/11 a expression and phagocytosis activity of leukocytes using flow cytometry analysis.Methods:The effects of methanolic extracts on CD18/11 a expression and phagocytosis of leukocytes were measured by labelling the cells with CD18-fluorescein isolhiocyanaie and ingestion labelled with Escherichia coli-fluorescein isothiocyanate and then analyzed using flow cytometer.Results:About 12 out of 20 methanolic extracts of selected Malaysian medicinal plants significantly(P≤0.05) inhibited the CD18/1 la expression of leukocytes at both concentrations of 6.25 μg/mL and 100 μg/mL in dose dependent manner.The most active inhibitory was shown in Citrus aurantifolia(Christm.) Swingle and Alpinia galangal(L.) Willd.at dosage 100ug/mL.Moreover,the Orthosiphon aristatus(Blume) Miq(O.aristatus).showed the highest stimulatory activity at the concentration of 100 μg/mL.Other than that,four plant extracts significantly(P<0.05) rose the phagocytosis activities of leukocytes in dose dependent manner.However,Annona muricata L.and O.aristatus showed the highest stimulated activities at the 100 pg/mL concentration.Conclusions:The results suggest that methanolic extracts of Cirrus aurantifolia.Alpinia gaiangal,O.aristatus and Annona muricata are able to modulate innate immune system and can potentially be recognized as therapeutic agents for modulating immune system.展开更多
Four successive mass selection lines of the Pacific oyster, Crassostrea gigas, selected for faster growth in breeding programs in China were examined at ten polymorphic microsatellite loci to assess the level of allel...Four successive mass selection lines of the Pacific oyster, Crassostrea gigas, selected for faster growth in breeding programs in China were examined at ten polymorphic microsatellite loci to assess the level of allelic diversity and estimate the effective population size. These data were compared with those of their base population. The results showed that the genetic variation of the four generations were maintained at high levels with an average allelic richness of 18.8–20.6, and a mean expected heterozygosity of 0.902–0.921. They were not reduced compared with those of their base population. Estimated effective population sizes based on temporal variances in microsatellite frequencies were smaller to that of sex ratio-corrected broodstock count estimates. Using a relatively large number of broodstock and keeping an equal sex ratio in the broodstock each generation may have contributed to retaining the original genetic diversity and maintaining relatively large effective population size. The results obtained in this study showed that the genetic variation was not affected greatly by mass selection progress and high genetic variation still existed in the mass selection lines, suggesting that there is still potential for increasing the gains in future generations of C. gigas. The present study provided important information for future genetic improvement by selective breeding, and for the design of suitable management guidelines for genetic breeding of C. gigas.展开更多
Through the study by electronic probe it was found that many new cracks and holes appear on the surface of gold bearing arsenopyrite crystal oxidized by Thiobacillus ferrooxidans, which are along with some directions....Through the study by electronic probe it was found that many new cracks and holes appear on the surface of gold bearing arsenopyrite crystal oxidized by Thiobacillus ferrooxidans, which are along with some directions. Then the selective bio oxidation model of gold bearing arsenopyrite was set up. The selective bio oxidation resulting from the submicro battery effect of gold/ arsenopyrite mineral pairs naturally forms in the gold bearing arsenopyrite crystal. Thiobacillus ferrooxidans has priority to oxidize the place of gold rich and oxidizes selectedly along with the crystal border, crystal face and crack. The bacteria oxidation process of gold bearing arsenopyrite is divided into three stages: the first stage is the surface oxidation, the second stage is restraining oxidation and the third stage is the filament oxidation, bacteria oxidize along with cracks of arsenopyrite.展开更多
[Objectives]This study was conducted to rationally and effectively use natural genetic resources of white birch(Betula platyphylla Suk.),and improve the scientific and technological content of improved varieties.[Meth...[Objectives]This study was conducted to rationally and effectively use natural genetic resources of white birch(Betula platyphylla Suk.),and improve the scientific and technological content of improved varieties.[Methods]With the progeny of the white birch populations naturally distributed in northern China as objects,based on genetic effect analysis and comprehensive evaluation,the genetic variation,heritability and genetic gain of the growth characters in the progeny forest were systematically analyzed,by which populations or individuals with good growth vigor and strong stress resistance and adaptability were finally selected.[Results]There were extremely significant differences in the growth characters between the natural populations of white birch in northern China.The variation was the smallest in tree height,followed by crown width,and largest in DBH,and the average coefficients of variation were 20.56%,32.25%and 33.00%,respectively.The differences in characters between progeny of the same population were also extremely significant.The growth characters of white birch were more controlled by genes,and the genetic gains were larger.The heritability of tree height,DBH and crown width was 0.971,0.816 and 0.576,respectively,and the genetic gains were 15.97%,21.54%and 13.87%,respectively.[Conclusions]With the growth characters as the main evaluation indexes,taking various influencing factors into account,the Shanxi[SX]population,Hebei[HB]population and Liaoning[LN]population were selected to be excellent populations,and LN305,SX516 and HB403 were excellent individuals,which are advised to be widely used in multi-generation genetic improvement breeding.展开更多
The selection for large and small relative brain weight (RBW) in mice, started in 1999, resulted in stable significant differences in the trait (16%). The selection was discontinued at F22, and both lines (Large Brain...The selection for large and small relative brain weight (RBW) in mice, started in 1999, resulted in stable significant differences in the trait (16%). The selection was discontinued at F22, and both lines (Large Brain, LB and Small brain, SB) were maintained by random mating. In F25-F28 the significant differences in RBW were still present in spite of the lack of selection. In F28 ethanol injections (2.4 mg/kg, 12% ethanol, i.p.) were performed to animals of both lines. The ethanol effects were more intense in SB, than in LB line. Mice were tested in elevated and closed plus-mazes and in slip-funnel tests. Control LB mice explored new environment more actively and were less affected by stressful environment than SBs. SB ethanol mice were less anxious in elevated plus maze, initiated closed maze exploration earlier, moved more vividly and demonstrated lower anxiety level in elevated plus maze than saline injected mice, while changes in these behaviors after ethanol were not so clear in LB mice, although their locomotion level increased.展开更多
Mutualisms are cooperative interactions between members of different species. We focus on obligate mutualism, where each species cannot survive without the other. From a theoretical aspect, obligate mutualism is simil...Mutualisms are cooperative interactions between members of different species. We focus on obligate mutualism, where each species cannot survive without the other. From a theoretical aspect, obligate mutualism is similar to the relationship between male and female. Empirical data indicate a sex-ratio selection: male and female have a specific ratio in their population sizes. In the present paper, we apply lattice model to obligate mutualism between two species, and present a theory of “ratio selection” which is a generalization of sex-ratio selection. Computer simulations are carried out by two methods: local and global interactions. In the former, interactions occur between neighbouring cells, while in the latter they occur between any pair of cells. Simulations in both interactions show the so-called Allee effect: both species can survive, when both densities are large in some extent. However, we find a large difference between local and global simulations. In the case of local interaction, restriction for survival is found to be extremely severe compared to global interaction. Both species require a proper ratio for their sustainability. This result leads to the theory of ratio selection: when interaction occurs locally, the ratio of both species is uniquely determined. We discuss that the ratio selection explains not only the evolution of endosymbionts from free-living ancestors but also the evolution from endosymbionts to organelles.展开更多
In the selective hydrogenation of diene (or alkyne) using heterogenized homogeneous catalyst, the high selectivity of monoene formation only appears in a very short time interval. The addition of suitable electron don...In the selective hydrogenation of diene (or alkyne) using heterogenized homogeneous catalyst, the high selectivity of monoene formation only appears in a very short time interval. The addition of suitable electron donors can decrease or even cease the monoene hydrogenation and thereby keep the high monoene selectivity after reaching its maximum.展开更多
In this paper,the functional polymeric active materials were prepared by the grafting copolymerization and their structure and properties were studied.The results show that the structure and properties of these ac- ti...In this paper,the functional polymeric active materials were prepared by the grafting copolymerization and their structure and properties were studied.The results show that the structure and properties of these ac- tive materials have the relative large effects on the properties of gadolinium ion selective electrodes.展开更多
Laboratory interspecific competition and grain-hosts selection experiments involving maize weevil (MW), Sitophilus zeamais (Motsch.) and larger grain borer (LGB), Prostephanus truncatus (Horn) were performed under amb...Laboratory interspecific competition and grain-hosts selection experiments involving maize weevil (MW), Sitophilus zeamais (Motsch.) and larger grain borer (LGB), Prostephanus truncatus (Horn) were performed under ambient temperature and relative humidity (25°C - 35°C and 70% - 80% relative humidity) in their major host cereal, maize grains. The species reproductive rate and grain-hosts preference were evaluated by a number of emerged adults. In combined infestation, both species competed intensively by simultaneously increasing their individuals’ emergence, 9-fold or greater than when reared alone. Even though both species simultaneously increased their progeny, S. zeamais was the dominant competitor and had a significant suppressant effect on P. truncatus. The selection result of grain-hosts showed that P. truncatus placed in the environment containing both uninfested maize grains and grains previously infested by S. zeamais, the insect prefers uninfested grains. Indeed, P. truncatus individuals’ emergences were significantly more important to uninfested grains than to infested grains. The weevil-infested grains seemed to have deterrent and detrimental effects on P. truncatus. Conversely, S. zeamais selection of grain-hosts was significantly (P = 0.0001) more attracted by P. truncatus infested grains than to uninfested grains. Sitophilus zeamais individuals’ emergences were significantly (P = 0.0008) more important to infested grains than to uninfested grains. The S. zeamais preference on grains previously infested would be stimulated by P. truncatus larval vibrations in grain.展开更多
文摘Under the background of a severe job market and fierce talent competition,the career planning education of college students is of great importance.In this study,a combination of quantitative and qualitative research methods was used;500 students in Shenzhen Polytechnic of Information Technology were surveyed by questionnaire,and 40 counselors were interviewed in depth to comprehensively analyze the role and practical effect of counselors in career planning education.The research showed that the role positioning of counselors includes the guide of students’career development,emotional support,and job-hunting strategy,and the specific path selection involves the strengthening of professional knowledge,the construction of interpersonal relationship networks,and personalized counseling.Based on the survey and interview data,this paper constructed a model for enhancing the role of counselors in career planning education and put forward a set of targeted work paths.
基金This work was supported by the Foundation for Innovative Research Groups of the National Natural Science Foundation of China(Grant No.52021003)National Natural Science Foundation of China(Grant No.51835006)+6 种基金the National Natural Science Foundation of China(Grant Nos.52222509,52105301,U19A20103)Jilin University Science and Technology Innovative Research Team(Grant No.2020TD-03)Interdisciplinary Integration and Innovation Project of JLU(Grant No.JLUXKJC2021ZZ03)the Natural Science Foundation of Jilin Province(Grant No.20220101220JC)Education Department of Jilin Province(Grant No.JJKH20220979KJ)Graduate Innovation Fund of Jilin University(2023CX077)supported by“Fundamental Research Funds for the Central Universities.”。
文摘Flexible strain sensors are promising in sensing minuscule mechanical signals,and thereby widely used in various advanced fields.However,the effective integration of hypersensitivity and highly selective response into one flexible strain sensor remains a huge challenge.Herein,inspired by the hysteresis strategy of the scorpion slit receptor,a bio-inspired flexible strain sensor(BFSS)with parallel through-slit arrays is designed and fabricated.Specifically,BFSS consists of conductive monolayer graphene and viscoelastic styrene–isoprene–styrene block copolymer.Under the synergistic effect of the bio-inspired slit structures and flexible viscoelastic materials,BFSS can achieve both hypersensitivity and highly selective frequency response.Remarkably,the BFSS exhibits a high gage factor of 657.36,and a precise identification of vibration frequencies at a resolution of 0.2 Hz through undergoing different morphological changes to high-frequency vibration and low-frequency vibration.Moreover,the BFSS possesses a wide frequency detection range(103 Hz)and stable durability(1000 cycles).It can sense and recognize vibration signals with different characteristics,including the frequency,amplitude,and waveform.This work,which turns the hysteresis effect into a"treasure,"can provide new design ideas for sensors for potential applications including human–computer interaction and health monitoring of mechanical equipment.
基金supported by the Key Research and Development Program of Hebei Province[20326333D]Science and Technology Promotion Demonstration Project of forestry and grassland in Hebei Province[Hebei TG[2019]001]Science and Technology Promotion Demonstration Project of forestry and grassland in Hebei Province[Hebei TG[2020]013]。
文摘Larix gmelinii var.principis-rupprechtii(Mayr.)Pilger is an important native tree species in North China with advantages of fast growth,straight trunk,and good wood properties.The multi-year and multi-site breeding research of families of the species has not been reported previously.Based on diameter at breast height(DBH),height and volume of 25 families on four experimental sites,we calculated variance components,genetic parameters,juvenile and mature trait correlations and made genotype main effect plus genotype×environment interaction effect(GGE)biplot based on the breeding values estimated using the method of best linear unbiased prediction(BLUP).Compared with height,DBH and volume had higher heritability and larger variation coefficients,making them the more suitable traits for family selection and evaluation.Based on these,GGE biplots containing 20 combinations of site×age were drawn using data at 13 to 17 years when the interactions between family and location were strong.Test sites classifications based on DBH,and volume were inconsistent,with two categories for DBH and one for volume.The Guyuan site was the most suitable with strong discriminating ability,high representativeness and stability among tree ages.Integrating the ranking results of DBH and volume,families 66,76,82 and 111 were high-yielding and stable,families 78 and96 were high-yielding with above average stability,families72 and 79 were high-yielding with below average stability,whereas stability of family 100 was inconsistent between DBH and volume.Early selection based on DBH was convenient and reliable,and can be made at seven years.This study provides support for the selection of Larix gmelinii var.principis-rupprechtii families in Hebei province and an example for the application of stem analysis data from multiple sites in tree breeding.
基金Sponsorship of the National Social Science Foundation (NSSF) Youth Project (16CJL014)the China Postdoctoral Science Special Foundation (2017T100001)
文摘Based on China's industrial enterprises-customs matched data, this paper utilizes two-tier stochastic frontier analysis method to estimate and verify the extent to which selection effect and competition effect influence exporting firms' markup. Our findings suggest that the interaction between selection effect and competition effect ultimately causes actual firm markup to be higher than the baseline markup by 7.11%. Exporting firms' actual markup is higher than the baseline markup by different degrees. In terms of the decomposition of selection effect, TFP explains for 28.05% of selection effect, and nonproductivity factors explain for the rest 71.95%. By controlling for the type of firms' export,the export-productivity paradox only exists for processing trade firms, which shows that with increasing trade facilitation, the policy incentives to encourage firms to export are major contributors to the low export markups.
文摘We consider the problem of variable selection for the single-index random effects models with longitudinal data. An automatic variable selection procedure is developed using smooth-threshold. The proposed method shares some of the desired features of existing variable selection methods: the resulting estimator enjoys the oracle property;the proposed procedure avoids the convex optimization problem and is flexible and easy to implement. Moreover, we use the penalized weighted deviance criterion for a data-driven choice of the tuning parameters. Simulation studies are carried out to assess the performance of our method, and a real dataset is analyzed for further illustration.
基金Project Supported by National Natural Science Foundation of China(50237010).
文摘This paper investigates the development,the breakdown process,and the discharge path selection of the lightning discharges in two-phase mixtures(TPMs).13 kinds of solid-gas mixtures and 3 kinds of liquid-gas mixtures are employed to study effect of two phase mixtures on the selection of the discharge path under lightning impulses.Grain size effects are shown upon these experimental results.When the diameter of solid or liquid grains is less than about 10 μm,the discharge path does not select TPM but air.And the discharge path selects TPM when the diameter is greater than about 100 μm.And when the diameter is between about 10 μm and 100 μm,the discharge path selects TPM under negative lightning impulses,but it has a greater selection of air than TPMs under positive lightning impulses.Volume fraction and permittivity of solid/liquid can also influence the selection of the discharge path.
基金supported by the National Natural Science Foundation of China (71772060).
文摘This research develops two new models for project portfolio selection, in which the candidate projects are composed of multiple repetitive units. To reflect some real situations, the learning effect is considered in the project portfolio selection problem for the first time. The mathematical representations of the relationship between learning experience and investment cost are provided. One numerical example under different scenarios is demonstrated and the impact of considering learning effect is then discussed.
文摘The F2, F3, families and F4 lines of six soybean crosses, were selected successively under high-and low - fertility sites with the relection objective of high yield and the method of pedigree was used. Two best F4 - derived lines were chosen from each of the six crosses under both high-and low-fertility for use in this study. In 1995, the total 24 lines were tested in high, medium and low fertility sites with the same experimental design (CRB) to study the selcctoin effects of high and low - fertility. The results suggested that high- and low-fertility had different selection effects. High fertility was more effective for selecting lines, which had higher yield under high-fertility and lower yield under low-fertility; low-fertility was better for selecting lines, which had higher yield under low-fertility and lower yield under low-fertility, and high fertility was somewhat better than low fertility for selecting lines, which had higher yield under both high and low-fertility. It revealed that the lines selected from high-fertility had superior yield potential. The lines selected from high-fertility had shorter plant height, more nodes on main stem, fewer branches, higher seed-stem ratio. The reverse was true for the lines selected from low-fertility . The lodging-resistance of the lines selected from highfertility was greater than that of the lines from low-fertility. The soil fertility level of breeding nursery should be chosen according to the breeding objective.
文摘This paper lays particular emphasis on pun's effectiveness and selectivity in English advertisements.The illustration and examples can help us understand the English advertisements well and foster our ability to appreciate the charm of English.
基金financially supported by the Jiangsu Agricultural Scientific Self-innovation Fund,China (CX(15)1057)the Fund of Science and Technology of Jiangsu Province,China (BE2015342)the National Key Research and Development Program of China (2017YFD0200400 and 2016YFD0300706)
文摘The green miridbug,Cyrtorhinus lividipennis,is an important predator of the rice brown planthopper,Nilaparvata lugens.In this study,the selective toxicity of seven commercial biopesticides for C.lividipennis was examined under laboratory conditions; abamectin was the most selective to C.lividipennis,followed by matrine and azadirachtin.Veratridine,rotenone,Bacillus thuringiensis and Beauveria bassiana showed less selectivity for C.lividipennis.Subsequently,matrine,abamectin and azadirachtin were selected for sublethal assessments with respect to C.lividipennis due to their high toxicities to N.lugens.C.lividipennis treated with sublethal concentrations(LC10 and LC20) of the three biopesticides could distinguish volatiles released from healthy and N.lugens-infested plants indicating that the biopesticides tested did not affect the foraging ability of surviving miridbugs.Azadirachtin decreased the consumption capability of C.lividipennis when the densities of N.lugens were 20,30,40 and 50 insects per vial.Sublethal concentration treatment did not impact the pre-oviposition period or egg hatchability of C.lividipennis.However,the fecundity of C.lividipennis exposed to azadirachtin and abamectin increased by 27–41% compared to the untreated individuals.In summary,abamectin or matrine together with C.lividipennis could be considered an effective,sustainable pest management strategy for rice.
基金Supported by National Basic Research Program of China (973Program) (2005CB321902) National Natural Science Foundation of China (90916024 60727002 60774003 60850004)+1 种基金 the Ph.D. Programs Foundation of Ministry of Education of China (20030006003) the Commission on Science Technology and Industry for National Defense (A2120061303)
基金Supported by Ministry of Higher Education.Malaysia(Grant No.GUP-SK-07-23-042)
文摘Objective:To investigate the effects of 20 methanolic extracts from Malaysian selected plants on CD18/11 a expression and phagocytosis activity of leukocytes using flow cytometry analysis.Methods:The effects of methanolic extracts on CD18/11 a expression and phagocytosis of leukocytes were measured by labelling the cells with CD18-fluorescein isolhiocyanaie and ingestion labelled with Escherichia coli-fluorescein isothiocyanate and then analyzed using flow cytometer.Results:About 12 out of 20 methanolic extracts of selected Malaysian medicinal plants significantly(P≤0.05) inhibited the CD18/1 la expression of leukocytes at both concentrations of 6.25 μg/mL and 100 μg/mL in dose dependent manner.The most active inhibitory was shown in Citrus aurantifolia(Christm.) Swingle and Alpinia galangal(L.) Willd.at dosage 100ug/mL.Moreover,the Orthosiphon aristatus(Blume) Miq(O.aristatus).showed the highest stimulatory activity at the concentration of 100 μg/mL.Other than that,four plant extracts significantly(P<0.05) rose the phagocytosis activities of leukocytes in dose dependent manner.However,Annona muricata L.and O.aristatus showed the highest stimulated activities at the 100 pg/mL concentration.Conclusions:The results suggest that methanolic extracts of Cirrus aurantifolia.Alpinia gaiangal,O.aristatus and Annona muricata are able to modulate innate immune system and can potentially be recognized as therapeutic agents for modulating immune system.
基金supported by grants from the National High Technology Research and Development Program (2012AA10A405-6)National Natural Science Foundation of China (31372524)Special Fund for Independent Innovation of Shandong Province (2013CX80202)
文摘Four successive mass selection lines of the Pacific oyster, Crassostrea gigas, selected for faster growth in breeding programs in China were examined at ten polymorphic microsatellite loci to assess the level of allelic diversity and estimate the effective population size. These data were compared with those of their base population. The results showed that the genetic variation of the four generations were maintained at high levels with an average allelic richness of 18.8–20.6, and a mean expected heterozygosity of 0.902–0.921. They were not reduced compared with those of their base population. Estimated effective population sizes based on temporal variances in microsatellite frequencies were smaller to that of sex ratio-corrected broodstock count estimates. Using a relatively large number of broodstock and keeping an equal sex ratio in the broodstock each generation may have contributed to retaining the original genetic diversity and maintaining relatively large effective population size. The results obtained in this study showed that the genetic variation was not affected greatly by mass selection progress and high genetic variation still existed in the mass selection lines, suggesting that there is still potential for increasing the gains in future generations of C. gigas. The present study provided important information for future genetic improvement by selective breeding, and for the design of suitable management guidelines for genetic breeding of C. gigas.
文摘Through the study by electronic probe it was found that many new cracks and holes appear on the surface of gold bearing arsenopyrite crystal oxidized by Thiobacillus ferrooxidans, which are along with some directions. Then the selective bio oxidation model of gold bearing arsenopyrite was set up. The selective bio oxidation resulting from the submicro battery effect of gold/ arsenopyrite mineral pairs naturally forms in the gold bearing arsenopyrite crystal. Thiobacillus ferrooxidans has priority to oxidize the place of gold rich and oxidizes selectedly along with the crystal border, crystal face and crack. The bacteria oxidation process of gold bearing arsenopyrite is divided into three stages: the first stage is the surface oxidation, the second stage is restraining oxidation and the third stage is the filament oxidation, bacteria oxidize along with cracks of arsenopyrite.
基金Supported by Heilongjiang Provincial Science and Technology Department Project(GC04B116)National Forest Tree Germplasm Resource Platform Running Service Project(2011DKA21003-02)National Forestry Public Welfare Industry Research Project(201204307-07)
文摘[Objectives]This study was conducted to rationally and effectively use natural genetic resources of white birch(Betula platyphylla Suk.),and improve the scientific and technological content of improved varieties.[Methods]With the progeny of the white birch populations naturally distributed in northern China as objects,based on genetic effect analysis and comprehensive evaluation,the genetic variation,heritability and genetic gain of the growth characters in the progeny forest were systematically analyzed,by which populations or individuals with good growth vigor and strong stress resistance and adaptability were finally selected.[Results]There were extremely significant differences in the growth characters between the natural populations of white birch in northern China.The variation was the smallest in tree height,followed by crown width,and largest in DBH,and the average coefficients of variation were 20.56%,32.25%and 33.00%,respectively.The differences in characters between progeny of the same population were also extremely significant.The growth characters of white birch were more controlled by genes,and the genetic gains were larger.The heritability of tree height,DBH and crown width was 0.971,0.816 and 0.576,respectively,and the genetic gains were 15.97%,21.54%and 13.87%,respectively.[Conclusions]With the growth characters as the main evaluation indexes,taking various influencing factors into account,the Shanxi[SX]population,Hebei[HB]population and Liaoning[LN]population were selected to be excellent populations,and LN305,SX516 and HB403 were excellent individuals,which are advised to be widely used in multi-generation genetic improvement breeding.
文摘The selection for large and small relative brain weight (RBW) in mice, started in 1999, resulted in stable significant differences in the trait (16%). The selection was discontinued at F22, and both lines (Large Brain, LB and Small brain, SB) were maintained by random mating. In F25-F28 the significant differences in RBW were still present in spite of the lack of selection. In F28 ethanol injections (2.4 mg/kg, 12% ethanol, i.p.) were performed to animals of both lines. The ethanol effects were more intense in SB, than in LB line. Mice were tested in elevated and closed plus-mazes and in slip-funnel tests. Control LB mice explored new environment more actively and were less affected by stressful environment than SBs. SB ethanol mice were less anxious in elevated plus maze, initiated closed maze exploration earlier, moved more vividly and demonstrated lower anxiety level in elevated plus maze than saline injected mice, while changes in these behaviors after ethanol were not so clear in LB mice, although their locomotion level increased.
文摘Mutualisms are cooperative interactions between members of different species. We focus on obligate mutualism, where each species cannot survive without the other. From a theoretical aspect, obligate mutualism is similar to the relationship between male and female. Empirical data indicate a sex-ratio selection: male and female have a specific ratio in their population sizes. In the present paper, we apply lattice model to obligate mutualism between two species, and present a theory of “ratio selection” which is a generalization of sex-ratio selection. Computer simulations are carried out by two methods: local and global interactions. In the former, interactions occur between neighbouring cells, while in the latter they occur between any pair of cells. Simulations in both interactions show the so-called Allee effect: both species can survive, when both densities are large in some extent. However, we find a large difference between local and global simulations. In the case of local interaction, restriction for survival is found to be extremely severe compared to global interaction. Both species require a proper ratio for their sustainability. This result leads to the theory of ratio selection: when interaction occurs locally, the ratio of both species is uniquely determined. We discuss that the ratio selection explains not only the evolution of endosymbionts from free-living ancestors but also the evolution from endosymbionts to organelles.
文摘In the selective hydrogenation of diene (or alkyne) using heterogenized homogeneous catalyst, the high selectivity of monoene formation only appears in a very short time interval. The addition of suitable electron donors can decrease or even cease the monoene hydrogenation and thereby keep the high monoene selectivity after reaching its maximum.
文摘In this paper,the functional polymeric active materials were prepared by the grafting copolymerization and their structure and properties were studied.The results show that the structure and properties of these ac- tive materials have the relative large effects on the properties of gadolinium ion selective electrodes.
文摘Laboratory interspecific competition and grain-hosts selection experiments involving maize weevil (MW), Sitophilus zeamais (Motsch.) and larger grain borer (LGB), Prostephanus truncatus (Horn) were performed under ambient temperature and relative humidity (25°C - 35°C and 70% - 80% relative humidity) in their major host cereal, maize grains. The species reproductive rate and grain-hosts preference were evaluated by a number of emerged adults. In combined infestation, both species competed intensively by simultaneously increasing their individuals’ emergence, 9-fold or greater than when reared alone. Even though both species simultaneously increased their progeny, S. zeamais was the dominant competitor and had a significant suppressant effect on P. truncatus. The selection result of grain-hosts showed that P. truncatus placed in the environment containing both uninfested maize grains and grains previously infested by S. zeamais, the insect prefers uninfested grains. Indeed, P. truncatus individuals’ emergences were significantly more important to uninfested grains than to infested grains. The weevil-infested grains seemed to have deterrent and detrimental effects on P. truncatus. Conversely, S. zeamais selection of grain-hosts was significantly (P = 0.0001) more attracted by P. truncatus infested grains than to uninfested grains. Sitophilus zeamais individuals’ emergences were significantly (P = 0.0008) more important to infested grains than to uninfested grains. The S. zeamais preference on grains previously infested would be stimulated by P. truncatus larval vibrations in grain.