BACKGROUND The relation between orthodontic treatment and temporomandibular disorders(TMDs)is under debate;the management of TMD during orthodontic treatment has always been a challenge.If TMD symptoms occur during or...BACKGROUND The relation between orthodontic treatment and temporomandibular disorders(TMDs)is under debate;the management of TMD during orthodontic treatment has always been a challenge.If TMD symptoms occur during orthodontic treatment,an immediate pause of orthodontic adjustments is recommended;the treatment can resume when the symptoms are managed and stabilized.CASE SUMMARY This case report presents a patient(26-year-old,female)with angle class I,skeletal class II and TMDs.The treatment was a hybrid of clear aligners,fixed appliances and temporary anchorage devices(TADs).After 3 mo resting and treatment on her TMD,the patient’s TMD symptom alleviated,but her anterior occlusion displayed deep overbite.Therefore,the fixed appliances with TAD were used to correct the anterior deep-bite and level maxillary and mandibular deep curves.After the levelling,the patient showed dual bite with centric relation and maximum intercuspation discrepancy on her occlusion.After careful examination of temporomandibular joints(TMJ)position,the stable bite splint and Invisible Mandibular Advancement appliance were used to reconstruct her occlusion.Eventually,the improved facial appearance and relatively stable occlusion were achieved.The 1-year follow-up records showed there was no obvious change in TMJ morphology,and her occlusion was stable.CONCLUSION TMD screening and monitoring is of great clinical importance in the TMD susceptible patients.Hybrid treatment with clear aligners and fixed appliances and TADs is an effective treatment modality for the complex cases.展开更多
Extensive numerical simulations and scaling analysis are performed to investigate competitive growth between the linear and nonlinear stochastic dynamic growth systems, which belong to the Edwards–Wilkinson(EW) and K...Extensive numerical simulations and scaling analysis are performed to investigate competitive growth between the linear and nonlinear stochastic dynamic growth systems, which belong to the Edwards–Wilkinson(EW) and Kardar–Parisi–Zhang(KPZ) universality classes, respectively. The linear growth systems include the EW equation and the model of random deposition with surface relaxation(RDSR), the nonlinear growth systems involve the KPZ equation and typical discrete models including ballistic deposition(BD), etching, and restricted solid on solid(RSOS). The scaling exponents are obtained in both the(1 + 1)-and(2 + 1)-dimensional competitive growth with the nonlinear growth probability p and the linear proportion 1-p. Our results show that, when p changes from 0 to 1, there exist non-trivial crossover effects from EW to KPZ universality classes based on different competitive growth rules. Furthermore, the growth rate and the porosity are also estimated within various linear and nonlinear growths of cooperation and competition.展开更多
This study analyzed the difference between using a downward breaststroke kick and a horizontal breaststroke kick in a sample of world class elite swimmers.We compared average muscle activity of the gluteus maximus,qua...This study analyzed the difference between using a downward breaststroke kick and a horizontal breaststroke kick in a sample of world class elite swimmers.We compared average muscle activity of the gluteus maximus,quadriceps femoris(vastus medialis and rectus femoris),hamstring/long head of the biceps femoris,gastrocnemius medialis,rectus abdominal,and erector spinae when using the downward breaststroke kick technique.We find that when this sample of swimmers utilized the downward breaststroke kick,max speed and velocity per stroke increased,measured by 12,788 EMG samples,where the results are highly correlated to duration of the aerodynamic buoyant force in breaststroke kick technique.The increases in performance observed from measuring the world class elite swimmers is highly correlated to the duration of the kick aerodynamic buoyant force.Among this sample of elite swimmers,the longer a swimmer demonstrates a buoyant force breaststroke kick,the lower the time in a 100 breaststroke.展开更多
One-class classification problem has become a popular problem in many fields, with a wide range of applications in anomaly detection, fault diagnosis, and face recognition. We investigate the one-class classification ...One-class classification problem has become a popular problem in many fields, with a wide range of applications in anomaly detection, fault diagnosis, and face recognition. We investigate the one-class classification problem for second-order tensor data. Traditional vector-based one-class classification methods such as one-class support vector machine (OCSVM) and least squares one-class support vector machine (LSOCSVM) have limitations when tensor is used as input data, so we propose a new tensor one-class classification method, LSOCSTM, which directly uses tensor as input data. On one hand, using tensor as input data not only enables to classify tensor data, but also for vector data, classifying it after high dimensionalizing it into tensor still improves the classification accuracy and overcomes the over-fitting problem. On the other hand, different from one-class support tensor machine (OCSTM), we use squared loss instead of the original loss function so that we solve a series of linear equations instead of quadratic programming problems. Therefore, we use the distance to the hyperplane as a metric for classification, and the proposed method is more accurate and faster compared to existing methods. The experimental results show the high efficiency of the proposed method compared with several state-of-the-art methods.展开更多
The small-scale drilling technique can be a fast and reliable method to estimate rock strength parameters. It needs to link the operational drilling parameters and strength properties of rock. The parameters such as b...The small-scale drilling technique can be a fast and reliable method to estimate rock strength parameters. It needs to link the operational drilling parameters and strength properties of rock. The parameters such as bit geometry, bit movement, contact frictions and crushed zone affect the estimated parameters.An analytical model considering operational drilling data and effective parameters can be used for these purposes. In this research, an analytical model was developed based on limit equilibrium of forces in a Tshaped drag bit considering the effective parameters such as bit geometry, crushed zone and contact frictions in drilling process. Based on the model, a method was used to estimate rock strength parameters such as cohesion, internal friction angle and uniaxial compressive strength of different rock types from operational drilling data. Some drilling tests were conducted by a portable and powerful drilling machine which was developed for this work. The obtained results for strength properties of different rock types from the drilling experiments based on the proposed model are in good agreement with the results of standard tests. Experimental results show that the contact friction between the cutting face and rock is close to that between bit end wearing face and rock due to the same bit material. In this case,the strength parameters, especially internal friction angle and cohesion, are estimated only by using a blunt bit drilling data and the bit bluntness does not affect the estimated results.展开更多
The conventional Duffing oscillator weak signal detection method, which is based on a strong reference signal, has inherent deficiencies. To address these issues, the characteristics of the Duffing oscillator's phase...The conventional Duffing oscillator weak signal detection method, which is based on a strong reference signal, has inherent deficiencies. To address these issues, the characteristics of the Duffing oscillator's phase trajectory in a small- scale periodic state are analyzed by introducing the theory of stopping oscillation system. Based on this approach, a novel Duffing oscillator weak wide-band signal detection method is proposed. In this novel method, the reference signal is discarded, and the to-be-detected signal is directly used as a driving force. By calculating the cosine function of a phase space angle, a single Duffing oscillator can be used for weak wide-band signal detection instead of an array of uncoupled Duffing oscillators. Simulation results indicate that, compared with the conventional Duffing oscillator detection method, this approach performs better in frequency detection intervals, and reduces the signal-to-noise ratio detection threshold, while improving the real-time performance of the system.展开更多
This paper attempts to study dolomite failure using small-scale blast tests.The experimental setup consisted of a cylindrical specimen with a central borehole fitted with a detonation cord inside a copper pipe.The spe...This paper attempts to study dolomite failure using small-scale blast tests.The experimental setup consisted of a cylindrical specimen with a central borehole fitted with a detonation cord inside a copper pipe.The specimen was confined using lead material.During the test,acceleration histories were recorded using sensors placed on the lead confinement.The results showed that heterogeneity and initial cracks significantly influenced the observed failure and cracking patterns.The tests were numerically represented using the previously validated Johnson-HolmquistⅡ(JH-2)constitutive model.The properties of the detonation cord were first determined and verified in a special test with a lead specimen to compare the deformation in the test with that of numerical simulation.Then,the small-scale blast test was simulated,and the failure of the dolomite was compared with the test observations.Comparisons of acceleration histories,scabbing failure,and number of radial cracks and crack density confirmed the overall repeatability of the actual testing data.It is likely that the proposed model can be further used for numerical studies of blasting of dolomite rock.展开更多
In recent years, China has been frequented by floods and droughts which has greatly evoked much concern from the Central Government about rural water conservancy construction. Irrigation is closely related to the &quo...In recent years, China has been frequented by floods and droughts which has greatly evoked much concern from the Central Government about rural water conservancy construction. Irrigation is closely related to the "three rural" issues and concerns about the vital interests of farmers. To achieve a virtuous circle of agricultural water supply, it is necessary and urgent to establish Farmer Water User Association (FWUA) to participate in the construction, management and maintenance of small-scale irrigation system. Based on the survey on nationwide "Small-scale irrigation conditions", the roles of FWUA in the construction, management and maintenance of small-scale water conservancy have studied in this study.展开更多
It has been shown that farmers with limited knowledge of the use and safe handling of pesticides may suffer exposure which results in adverse health effects. In Buea, Cameroon, small-scale tomato farmers commonly use ...It has been shown that farmers with limited knowledge of the use and safe handling of pesticides may suffer exposure which results in adverse health effects. In Buea, Cameroon, small-scale tomato farmers commonly use pesticides for pest control. Information was obtained from these tomato farmers to determine the extent and types of their pesticide use, their knowledge of pesticide use and effectiveness, and their perception of potential harm resulting from pesticide use. A standardized questionnaire, interviews, field observations and an analytical ranking game were used to describe the pesticide use of 93 tomato farmers. Many farmers (47.6%) used pyrethiod and organophosphorus insecticides and identified these chemicals as the most effective in pesticide control;these are WHO Class II pesticides which are the most hazardous to humans. Most farmers (83.8%) used knapsack sprayers to apply pesticides, with 76.3% using no or partial personal protective equipment (PPE). It was notable that 55.5% of farmers expressed no concern regarding the wind direction (pesticide drift) during spraying. The results showed a significant association between the method of pesticides application and farm size (P < 0.001). Most farmers (85.0%) reported at least one symptom of acute pesticide poisoning following spraying. This study revealed that the tomato farmers have a high exposure to pesticides secondary to inadequate knowledge of the safe and judicious use of pesticides. Strategies that provide training on the appropriate use of pesticides, how to reduce exposure to and health risks of pesticides and alternative options of pest management and control are required. The study also raised concerns that further control of the sale and distribution of pesticides may be indicated.展开更多
Large-scaled reclamation modifies the coastal environment dramatically while accelerating the disappearance of salt marshes,which causes the degradation of the coastal ecosystem and the biodiversity function.In this s...Large-scaled reclamation modifies the coastal environment dramatically while accelerating the disappearance of salt marshes,which causes the degradation of the coastal ecosystem and the biodiversity function.In this study,we explored the changes of tidal flat and salt marsh coverage in a small-scale tidal flat with an area of ~160 000 m^2 in the plain coast of Jiangsu Province,China.Human activities(e.g.,the construction of dikes) are a crucial contributor that benefits for the tidal flat accretions and the following changes of salt marsh coverage.Located in the front of the man-made "concave coastline",the study area is suitable for sediment accretion after the dike construction in the end of 2006.On the basis of the annual tidal surface elevation survey from 2007 to 2012,the sedimentation rates in the human influenced tidal flat varied from a few centimeters per year to 23 cm/a.The study area experienced a rapid accretion in the tidal flat and the expansion of the salt marsh,with the formation of a longshore bar,and a subsequent decline of the salt marsh.Breaking waves during the flooding tide brought much sediment from the adjacent tidal flat to the study area,which caused burial and degeneration of the salt marsh.The vertical grain size changes within a 66 cm long core in the study area also demonstrated the above changes in the tidal environment.This study indicates that the responses of small-scale tidal flat changes to reclamation are significant,and the rational reclamation would benefit for the new salt marsh formation in front of the dikes.Further research about the evolution of small scale tidal flat as well as the spatial planning of the polder dike should be strengthened for the purpose to maintain a healthier coastal environment.展开更多
Fisheries management worldwide struggles to strike a balance between protecting resources,ensuring fair access to resources and promoting economic effectiveness and stability.The transition to a participatory democrac...Fisheries management worldwide struggles to strike a balance between protecting resources,ensuring fair access to resources and promoting economic effectiveness and stability.The transition to a participatory democracy in South Africa in 1994 resulted in the transformation of government institutions and an extensive process of legislative reform regarding展开更多
Genes are continually being created by the processes of genome duplication (ohnolog) and gene duplication (paralog). Whole-genome duplications have been found to be widespread in plant species and play an importan...Genes are continually being created by the processes of genome duplication (ohnolog) and gene duplication (paralog). Whole-genome duplications have been found to be widespread in plant species and play an important role in plant evolution. Clearly un-overlapping duplicated blocks of whole-genome duplications can be detected in the genome of sequenced rice (Oryza sativa). Syntenic ohnolog pairs (ohnologues) of the whole-genome duplications in rice were identified based on their syntenic duplicate lines. The paralogs of ohnologues were further scanned using multi-round reciprocal BLAST best-hit searching (E〈e^-14). The results indicated that an average of 0.55 sister paralogs could be found for every ohnologue in rice. These results suggest that small-scale duplications, as well as whole-genome duplications, play a significant role in the two duplicated rice genomes.展开更多
Active control of a fully developed turbulence boundary layer(TBL) over a flat plate has been investigated with a statistical view. The piezoelectric(PZT) oscillator is employed to produce periodic input into the inne...Active control of a fully developed turbulence boundary layer(TBL) over a flat plate has been investigated with a statistical view. The piezoelectric(PZT) oscillator is employed to produce periodic input into the inner region of the TBL.A wall probe is fixed upstream of the oscillator to identify the high-or low-speed fluctuations as the detecting signals.Then, the impact of the detecting signals on the small-scale bursting process is investigated based on the data acquired by the traversing probe downstream of the oscillator. The results indicate that the small-scale bursting intensity is restrained more apparently at high-speed detecting fluctuations but less impacted at low-speed detecting fluctuations. Furthermore, the perturbed-scale fluctuations arrange the small-scale bursting process in the near-wall region. The detecting signals have an obvious impact on this arrangement, especially the high-intensity regions of the small-scale bursting events: the vibration enhances the intensity at high-speed detecting signals but weakens it at low-speed detecting signals in these regions, which gives a direct evidence on how detecting signals interfering the small-scale bursting process.展开更多
A theoretical model which describes the small-scale irregularities excited by powerful high frequency (3–30 MHz) electromagnetic wave in ionosphere heating is investigated quantitatively in this paper. The model is...A theoretical model which describes the small-scale irregularities excited by powerful high frequency (3–30 MHz) electromagnetic wave in ionosphere heating is investigated quantitatively in this paper. The model is based on the transport equation in magnetic plasma and mode conversion from electromagnetic wave to electrostatic wave in ionospheric modification.Threshold electric field for exciting small-scale (meter scale) irregularities and spatial spectra of irregularities are analytically calculated by this model. The results indicate that background electron density and geomagnetic field play an important role for the threshold electric field and the spatial scale of the electron density irregularities. The results demonstrate that the electric field threshold increases with the decrease of the spatial scale of the irregularities. For exciting meter scale irregularities, the threshold electric field is about tens of mV m^(-1). The theoretical results are consistent with those of the experiments.展开更多
In an attempt to identify solutions to the effects of erratic rainfall patterns and droughts that limit agricultural production growth,the Rwandan government has recently increased investments in irrigation developmen...In an attempt to identify solutions to the effects of erratic rainfall patterns and droughts that limit agricultural production growth,the Rwandan government has recently increased investments in irrigation development.In this study,we analyze the adoption of small-scale irrigation technologies(SSITs)and its impact on land productivity using cross-sectional data from a sample of 360 farmers in Rwanda.The study uses the propensity score matching technique to address potential self-selection bias.Our results reveal that adoption decisions are significantly influenced by factors such as education,farm size,group membership,gender,extension services,access to credit,access to weather forecast information,risk perceptions,access to a reliable source of water for irrigation,awareness of rainwater harvesting techniques,and awareness of subsidy programs.In addition,the results show that the adoption of SSITs has a significantly positive impact on land productivity.The study concludes with policy implications that highlight the need to promote the adoption of SSITs among farmers as a strategy to improve agricultural productivity and food security in Rwanda.展开更多
基金Natural Science Foundation of Jiangsu Province, No. SBK2021021787the Major Project of the Health Commission ofJiangsu Province, No. ZD2022025and the Key Project of the Nanjing Health Commission, No. ZKX20048.
文摘BACKGROUND The relation between orthodontic treatment and temporomandibular disorders(TMDs)is under debate;the management of TMD during orthodontic treatment has always been a challenge.If TMD symptoms occur during orthodontic treatment,an immediate pause of orthodontic adjustments is recommended;the treatment can resume when the symptoms are managed and stabilized.CASE SUMMARY This case report presents a patient(26-year-old,female)with angle class I,skeletal class II and TMDs.The treatment was a hybrid of clear aligners,fixed appliances and temporary anchorage devices(TADs).After 3 mo resting and treatment on her TMD,the patient’s TMD symptom alleviated,but her anterior occlusion displayed deep overbite.Therefore,the fixed appliances with TAD were used to correct the anterior deep-bite and level maxillary and mandibular deep curves.After the levelling,the patient showed dual bite with centric relation and maximum intercuspation discrepancy on her occlusion.After careful examination of temporomandibular joints(TMJ)position,the stable bite splint and Invisible Mandibular Advancement appliance were used to reconstruct her occlusion.Eventually,the improved facial appearance and relatively stable occlusion were achieved.The 1-year follow-up records showed there was no obvious change in TMJ morphology,and her occlusion was stable.CONCLUSION TMD screening and monitoring is of great clinical importance in the TMD susceptible patients.Hybrid treatment with clear aligners and fixed appliances and TADs is an effective treatment modality for the complex cases.
基金supported by Undergraduate Training Program for Innovation and Entrepreneurship of China University of Mining and Technology (CUMT)(Grant No. 202110290059Z)Fundamental Research Funds for the Central Universities of CUMT (Grant No. 2020ZDPYMS33)。
文摘Extensive numerical simulations and scaling analysis are performed to investigate competitive growth between the linear and nonlinear stochastic dynamic growth systems, which belong to the Edwards–Wilkinson(EW) and Kardar–Parisi–Zhang(KPZ) universality classes, respectively. The linear growth systems include the EW equation and the model of random deposition with surface relaxation(RDSR), the nonlinear growth systems involve the KPZ equation and typical discrete models including ballistic deposition(BD), etching, and restricted solid on solid(RSOS). The scaling exponents are obtained in both the(1 + 1)-and(2 + 1)-dimensional competitive growth with the nonlinear growth probability p and the linear proportion 1-p. Our results show that, when p changes from 0 to 1, there exist non-trivial crossover effects from EW to KPZ universality classes based on different competitive growth rules. Furthermore, the growth rate and the porosity are also estimated within various linear and nonlinear growths of cooperation and competition.
文摘This study analyzed the difference between using a downward breaststroke kick and a horizontal breaststroke kick in a sample of world class elite swimmers.We compared average muscle activity of the gluteus maximus,quadriceps femoris(vastus medialis and rectus femoris),hamstring/long head of the biceps femoris,gastrocnemius medialis,rectus abdominal,and erector spinae when using the downward breaststroke kick technique.We find that when this sample of swimmers utilized the downward breaststroke kick,max speed and velocity per stroke increased,measured by 12,788 EMG samples,where the results are highly correlated to duration of the aerodynamic buoyant force in breaststroke kick technique.The increases in performance observed from measuring the world class elite swimmers is highly correlated to the duration of the kick aerodynamic buoyant force.Among this sample of elite swimmers,the longer a swimmer demonstrates a buoyant force breaststroke kick,the lower the time in a 100 breaststroke.
文摘One-class classification problem has become a popular problem in many fields, with a wide range of applications in anomaly detection, fault diagnosis, and face recognition. We investigate the one-class classification problem for second-order tensor data. Traditional vector-based one-class classification methods such as one-class support vector machine (OCSVM) and least squares one-class support vector machine (LSOCSVM) have limitations when tensor is used as input data, so we propose a new tensor one-class classification method, LSOCSTM, which directly uses tensor as input data. On one hand, using tensor as input data not only enables to classify tensor data, but also for vector data, classifying it after high dimensionalizing it into tensor still improves the classification accuracy and overcomes the over-fitting problem. On the other hand, different from one-class support tensor machine (OCSTM), we use squared loss instead of the original loss function so that we solve a series of linear equations instead of quadratic programming problems. Therefore, we use the distance to the hyperplane as a metric for classification, and the proposed method is more accurate and faster compared to existing methods. The experimental results show the high efficiency of the proposed method compared with several state-of-the-art methods.
文摘The small-scale drilling technique can be a fast and reliable method to estimate rock strength parameters. It needs to link the operational drilling parameters and strength properties of rock. The parameters such as bit geometry, bit movement, contact frictions and crushed zone affect the estimated parameters.An analytical model considering operational drilling data and effective parameters can be used for these purposes. In this research, an analytical model was developed based on limit equilibrium of forces in a Tshaped drag bit considering the effective parameters such as bit geometry, crushed zone and contact frictions in drilling process. Based on the model, a method was used to estimate rock strength parameters such as cohesion, internal friction angle and uniaxial compressive strength of different rock types from operational drilling data. Some drilling tests were conducted by a portable and powerful drilling machine which was developed for this work. The obtained results for strength properties of different rock types from the drilling experiments based on the proposed model are in good agreement with the results of standard tests. Experimental results show that the contact friction between the cutting face and rock is close to that between bit end wearing face and rock due to the same bit material. In this case,the strength parameters, especially internal friction angle and cohesion, are estimated only by using a blunt bit drilling data and the bit bluntness does not affect the estimated results.
基金Project supported by the National Natural Science Foundation of China(Grant No.61673066)
文摘The conventional Duffing oscillator weak signal detection method, which is based on a strong reference signal, has inherent deficiencies. To address these issues, the characteristics of the Duffing oscillator's phase trajectory in a small- scale periodic state are analyzed by introducing the theory of stopping oscillation system. Based on this approach, a novel Duffing oscillator weak wide-band signal detection method is proposed. In this novel method, the reference signal is discarded, and the to-be-detected signal is directly used as a driving force. By calculating the cosine function of a phase space angle, a single Duffing oscillator can be used for weak wide-band signal detection instead of an array of uncoupled Duffing oscillators. Simulation results indicate that, compared with the conventional Duffing oscillator detection method, this approach performs better in frequency detection intervals, and reduces the signal-to-noise ratio detection threshold, while improving the real-time performance of the system.
基金supported by the Interdisciplinary Center for Mathematical and Computational Modeling(ICM),University of Warsaw(Grant No.GA73-19)as part of the implementation of the Military University of Technology(Grant No.22-876)。
文摘This paper attempts to study dolomite failure using small-scale blast tests.The experimental setup consisted of a cylindrical specimen with a central borehole fitted with a detonation cord inside a copper pipe.The specimen was confined using lead material.During the test,acceleration histories were recorded using sensors placed on the lead confinement.The results showed that heterogeneity and initial cracks significantly influenced the observed failure and cracking patterns.The tests were numerically represented using the previously validated Johnson-HolmquistⅡ(JH-2)constitutive model.The properties of the detonation cord were first determined and verified in a special test with a lead specimen to compare the deformation in the test with that of numerical simulation.Then,the small-scale blast test was simulated,and the failure of the dolomite was compared with the test observations.Comparisons of acceleration histories,scabbing failure,and number of radial cracks and crack density confirmed the overall repeatability of the actual testing data.It is likely that the proposed model can be further used for numerical studies of blasting of dolomite rock.
文摘In recent years, China has been frequented by floods and droughts which has greatly evoked much concern from the Central Government about rural water conservancy construction. Irrigation is closely related to the "three rural" issues and concerns about the vital interests of farmers. To achieve a virtuous circle of agricultural water supply, it is necessary and urgent to establish Farmer Water User Association (FWUA) to participate in the construction, management and maintenance of small-scale irrigation system. Based on the survey on nationwide "Small-scale irrigation conditions", the roles of FWUA in the construction, management and maintenance of small-scale water conservancy have studied in this study.
文摘It has been shown that farmers with limited knowledge of the use and safe handling of pesticides may suffer exposure which results in adverse health effects. In Buea, Cameroon, small-scale tomato farmers commonly use pesticides for pest control. Information was obtained from these tomato farmers to determine the extent and types of their pesticide use, their knowledge of pesticide use and effectiveness, and their perception of potential harm resulting from pesticide use. A standardized questionnaire, interviews, field observations and an analytical ranking game were used to describe the pesticide use of 93 tomato farmers. Many farmers (47.6%) used pyrethiod and organophosphorus insecticides and identified these chemicals as the most effective in pesticide control;these are WHO Class II pesticides which are the most hazardous to humans. Most farmers (83.8%) used knapsack sprayers to apply pesticides, with 76.3% using no or partial personal protective equipment (PPE). It was notable that 55.5% of farmers expressed no concern regarding the wind direction (pesticide drift) during spraying. The results showed a significant association between the method of pesticides application and farm size (P < 0.001). Most farmers (85.0%) reported at least one symptom of acute pesticide poisoning following spraying. This study revealed that the tomato farmers have a high exposure to pesticides secondary to inadequate knowledge of the safe and judicious use of pesticides. Strategies that provide training on the appropriate use of pesticides, how to reduce exposure to and health risks of pesticides and alternative options of pest management and control are required. The study also raised concerns that further control of the sale and distribution of pesticides may be indicated.
基金The National Key Technology Research and Development Program of the Ministry of Science and Technology of China under contract No.2012BAC07B01the National Natural Science Foundation of China under contract Nos 41371024,41230751 and 41071006
文摘Large-scaled reclamation modifies the coastal environment dramatically while accelerating the disappearance of salt marshes,which causes the degradation of the coastal ecosystem and the biodiversity function.In this study,we explored the changes of tidal flat and salt marsh coverage in a small-scale tidal flat with an area of ~160 000 m^2 in the plain coast of Jiangsu Province,China.Human activities(e.g.,the construction of dikes) are a crucial contributor that benefits for the tidal flat accretions and the following changes of salt marsh coverage.Located in the front of the man-made "concave coastline",the study area is suitable for sediment accretion after the dike construction in the end of 2006.On the basis of the annual tidal surface elevation survey from 2007 to 2012,the sedimentation rates in the human influenced tidal flat varied from a few centimeters per year to 23 cm/a.The study area experienced a rapid accretion in the tidal flat and the expansion of the salt marsh,with the formation of a longshore bar,and a subsequent decline of the salt marsh.Breaking waves during the flooding tide brought much sediment from the adjacent tidal flat to the study area,which caused burial and degeneration of the salt marsh.The vertical grain size changes within a 66 cm long core in the study area also demonstrated the above changes in the tidal environment.This study indicates that the responses of small-scale tidal flat changes to reclamation are significant,and the rational reclamation would benefit for the new salt marsh formation in front of the dikes.Further research about the evolution of small scale tidal flat as well as the spatial planning of the polder dike should be strengthened for the purpose to maintain a healthier coastal environment.
文摘Fisheries management worldwide struggles to strike a balance between protecting resources,ensuring fair access to resources and promoting economic effectiveness and stability.The transition to a participatory democracy in South Africa in 1994 resulted in the transformation of government institutions and an extensive process of legislative reform regarding
基金the National NaturalSciencc Foundation of China (90208022,30471067) IBM Shared University Research (LifeScience).
文摘Genes are continually being created by the processes of genome duplication (ohnolog) and gene duplication (paralog). Whole-genome duplications have been found to be widespread in plant species and play an important role in plant evolution. Clearly un-overlapping duplicated blocks of whole-genome duplications can be detected in the genome of sequenced rice (Oryza sativa). Syntenic ohnolog pairs (ohnologues) of the whole-genome duplications in rice were identified based on their syntenic duplicate lines. The paralogs of ohnologues were further scanned using multi-round reciprocal BLAST best-hit searching (E〈e^-14). The results indicated that an average of 0.55 sister paralogs could be found for every ohnologue in rice. These results suggest that small-scale duplications, as well as whole-genome duplications, play a significant role in the two duplicated rice genomes.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.11972251,11732010,11572221,11502066,and 11872272)。
文摘Active control of a fully developed turbulence boundary layer(TBL) over a flat plate has been investigated with a statistical view. The piezoelectric(PZT) oscillator is employed to produce periodic input into the inner region of the TBL.A wall probe is fixed upstream of the oscillator to identify the high-or low-speed fluctuations as the detecting signals.Then, the impact of the detecting signals on the small-scale bursting process is investigated based on the data acquired by the traversing probe downstream of the oscillator. The results indicate that the small-scale bursting intensity is restrained more apparently at high-speed detecting fluctuations but less impacted at low-speed detecting fluctuations. Furthermore, the perturbed-scale fluctuations arrange the small-scale bursting process in the near-wall region. The detecting signals have an obvious impact on this arrangement, especially the high-intensity regions of the small-scale bursting events: the vibration enhances the intensity at high-speed detecting signals but weakens it at low-speed detecting signals in these regions, which gives a direct evidence on how detecting signals interfering the small-scale bursting process.
基金supported by National Natural Science Foundation of China(NSFC grants 41204111,4157414641774162 and 41704155)China Postdoctoral Science Foundation(2017M622504)
文摘A theoretical model which describes the small-scale irregularities excited by powerful high frequency (3–30 MHz) electromagnetic wave in ionosphere heating is investigated quantitatively in this paper. The model is based on the transport equation in magnetic plasma and mode conversion from electromagnetic wave to electrostatic wave in ionospheric modification.Threshold electric field for exciting small-scale (meter scale) irregularities and spatial spectra of irregularities are analytically calculated by this model. The results indicate that background electron density and geomagnetic field play an important role for the threshold electric field and the spatial scale of the electron density irregularities. The results demonstrate that the electric field threshold increases with the decrease of the spatial scale of the irregularities. For exciting meter scale irregularities, the threshold electric field is about tens of mV m^(-1). The theoretical results are consistent with those of the experiments.
基金This work was supported by the Research Scholarship of Chungnam National University,South Korea.
文摘In an attempt to identify solutions to the effects of erratic rainfall patterns and droughts that limit agricultural production growth,the Rwandan government has recently increased investments in irrigation development.In this study,we analyze the adoption of small-scale irrigation technologies(SSITs)and its impact on land productivity using cross-sectional data from a sample of 360 farmers in Rwanda.The study uses the propensity score matching technique to address potential self-selection bias.Our results reveal that adoption decisions are significantly influenced by factors such as education,farm size,group membership,gender,extension services,access to credit,access to weather forecast information,risk perceptions,access to a reliable source of water for irrigation,awareness of rainwater harvesting techniques,and awareness of subsidy programs.In addition,the results show that the adoption of SSITs has a significantly positive impact on land productivity.The study concludes with policy implications that highlight the need to promote the adoption of SSITs among farmers as a strategy to improve agricultural productivity and food security in Rwanda.