A review of the period of unregulated exploitation of forests in the state of West Virginia (U.S.) and in Shaanxi Province, PRC was presented. Economic and ecological recovery from exploitation has been different in t...A review of the period of unregulated exploitation of forests in the state of West Virginia (U.S.) and in Shaanxi Province, PRC was presented. Economic and ecological recovery from exploitation has been different in the two regions due to basic differences in nature of the forest and in the degree and persistence of exploitive pressures. After a century since unregulated exploitation, West Virginia forests are well on the road to management for sustainability and conservation. Shaanxi's recovery from overuse and unregulated exploitation is less certain; forests are still in the early phases of ecological recovery there. Full recovery to a period of sustainability will take a century or longer. Suggestions are made for measures needed to enhance the forest recovery. Keywords Forests - Shaanxi - West Virginia - Central China - Forest exploitation - Recovery CLC number S754 Document code A Article ID 1007-662X(2004)01-0049-06 Foundation item: The project was sponsored by the Scientific Research Foundation for the Returned Overseas Chinese Scholars, State Education Ministry (2002–2004) and Shaanxi Provincial Foreign Expert Bureau (2003).Biography: Jack E. Coster (1935-), male, professor of West Virginia University, Morgantown, West Virginia. U.S.A.Responsible editor: Song Funan展开更多
The lower Mississippi River(LMR) has been heavily modified for multiple human purposes such as navigation, flood control, and bank stabilization. However, the LMR simultaneously supports a diverse fish fauna that incl...The lower Mississippi River(LMR) has been heavily modified for multiple human purposes such as navigation, flood control, and bank stabilization. However, the LMR simultaneously supports a diverse fish fauna that includes recreational and commercial fisheries. Due to river training and diversion structures constructed during the past 80 years, the historic characteristics of the LMR have been drastically altered and have likely influenced fishes and fisheries in the system. One common restoration measure used throughout the LMR has been to "notch" wing-dike structures that close secondary(side) river channels. Dike notching allows year-round flows through secondary channels, which enhances habitat diversity and promotes biological productivity at the ecosystem scale. Although notching is presumed good for LMR fishes and other biota, few studies have examined its effects on fish assemblages. In this study, fish assemblages were sampled at seven LMR secondary channels spanning from river kilometer(rkm) 628(Louisiana-Mississippi, U.S.A.) upstream to rkm 1504(Missouri-Kentucky, U.S.A.). Four secondary channels were termed "permanent"(i.e.,with notched dikes) while three secondary channels were termed "temporary"(i.e., without notched dikes).Fishes were sampled by boat-mounted electrofishing conducted during falling and low stages from1995—1997. Fish assemblages differed between permanent and temporary secondary channels, and varied somewhat between falling and low stages. Gizzard shad(Dorosoma cepedianum), threadfin shad(D. petenense), and white bass(Morone chrysops) demonstrated consistent preferences for low-current conditions associated with temporary secondary channels. Conversely, blue catfish(Ictalurus furcatus), flathead catfish(Pylodictis olivaris), and freshwater drum(Aplodinotus grunniens) were more associated with permanent secondary channels. Future restoration strategies in the LMR should consider dike notching and resultant maintenance of permanent secondary channels in selected river reaches. However, temporary secondary channels also contain unique fish species, and also appear to be important sites of riverine primary production. Restoration strategies should consider a balance of both secondary channel types, which should support the greatest biodiversity for the LMR ecosystem.展开更多
I offer suggestions to increase the probability of success of an international research project.Collaborative studies often produce more innovative and transformative scientific results than work done by a single inve...I offer suggestions to increase the probability of success of an international research project.Collaborative studies often produce more innovative and transformative scientific results than work done by a single investigator or an isolated team.My advice is intended for early-career scientists.The product of the collaboration may be high-impact research publications,enhanced geophysical monitoring capabilities in a foreign country,or an advanced training course.Choosing the right international partner is the most important step.Keeping an open mind and being receptive to suggestions to modify the initial concept is critical.Other key steps include having a mutually agreed upon plan with achievable goals and well-defined expected outcomes.International cooperation is a richly rewarding experience that accelerates progress in the Earth Sciences.展开更多
When making assessments of forest resources,there is nearly ubiquitous interest in quantifying current status and trends in tree biomass and carbon stocks.While important at various spatial scales,typical estimations ...When making assessments of forest resources,there is nearly ubiquitous interest in quantifying current status and trends in tree biomass and carbon stocks.While important at various spatial scales,typical estimations pertinent to broad forest management and policy issues are conducted for large areas such as state,regional,and national perspectives.These assessments are usually accomplished using large-area forest inventory data collected by National Forest Inventory(NFI)programs.While NFI efforts commonly collect size data for individual trees,there is often limited information for tree seedlings,e.g.,frequency by species.To fully describe the tree population across the entire range of sizes present,this study proposes methods to predict individual seedling groundline diameter and height using models developed from trees having a diameter at breast height(DBH)less than 7.62 cm.These attributes are subsequently used for the prediction of seedling stem volume,total aboveground biomass,and carbon content.The results suggest a smooth transition in tree attributes as size increases to where direct measurement of individual trees and prediction of their volume,biomass,and carbon are implemented as part of standard inventory protocols.Analyses including the full spectrum of tree sizes show that seedlings contribute roughly 0.6%–0.7%of the total tree volume/mass.This additional suite of information provides opportunities for more holistic assessments across the full spectrum of the tree resource or for specialized subdomains that include the seedling component.展开更多
It is well known that critical points of the total scalar curvature functional S on the space of all smooth Riemannian structures of volume 1 on a compact manifold M are exactly the Einstein metrics.When the domain of...It is well known that critical points of the total scalar curvature functional S on the space of all smooth Riemannian structures of volume 1 on a compact manifold M are exactly the Einstein metrics.When the domain of S is restricted to the space of constant scalar curvature metrics,there has been a conjecture that a critical point is also Einstein or isometric to a standard sphere.In the Riemannian case,it’s tangent space satisfies a decomposition.In this paper,we prove that if we only consider the Hermitian metrics,it also have a decomposition.Then we obtain the equation of the critical points among the Hermitian metrics.展开更多
The Leafminers,representing a diverse group of insects from various genera within the Agromyzidae family,pose a significant threat to spinach(Spinacia oleracea L.)production.This study aimed to identify single nucleot...The Leafminers,representing a diverse group of insects from various genera within the Agromyzidae family,pose a significant threat to spinach(Spinacia oleracea L.)production.This study aimed to identify single nucleotide polymorphism(SNP)markers associated with leafminer resistance through a genome-wide association study(GWAS)and to evaluate the prediction accuracy(PA)for selecting resistant spinach using genomic prediction(GP).Using a dataset of 84301 SNPs obtained from whole-genome resequencing,seven GWAS models,including BLINK,FarmCPU,MLM,and MLMM in GAPIT 3,as well as MLM,GLM,and SMR in TASSEL 5,were employed to perform GWAS on a panel of 286 USDA spinach germplasm accessions.Three SNP markers,namely 1_115279256_C_T,3_157082529_C_T,and 4_168510908_T_G on chromosomes 1,3,and 4,respectively,were identified as associated with leafminer resistance.In the 30 kb flanking regions of these markers,four candidate genes(SOV1g031330,SOV1g031340,SOV4g047270,and SOV4g047280),encoding LOB domain-containing protein,KH domain-containing protein,were discovered.Nodulin-like domain-containing protein,and SAM domain-containing protein,were discovered.The PA for leafminer resistance selection was estimated using ten different SNP sets,including two GWAS-derived marker sets(three and 51 SNPs)and eight random marker sets(ranging from 51 to 10 K SNPs)analyzed by seven GP models.The findings emphasized the superior performance of GWAS-derived SNP sets,reaching a PA of up to 0.79 using the cBLUP model.Notably,this research marks the pioneering application of GP in the context of insect resistance,providing a significant advancement in the understanding and management of leafminer resistance in spinach cultivation.展开更多
Acute exposure to high altitude can cause acute altitude illnesses and is associated with impaired cognitive and physical performance.The most effective preventive strategies currently recommended include environmenta...Acute exposure to high altitude can cause acute altitude illnesses and is associated with impaired cognitive and physical performance.The most effective preventive strategies currently recommended include environmental acclimatization(slow ascent and/or pre-acclimatization)or pharmacological support of acclimatization using acetazolamide.However,these strategies are not practical for high-altitude exposures that require rapid and unplanned ascent,high physical and mental performance,such as rescue missions or military operations.Dexamethasone and other modulators of the glucocorticoid system take effect quickly and are effective alternatives for preventing acute altitude illnesses when rapidly ascending to high altitudes.As the efficacy of dexamethasone in preventing acute mountain illnesses remains controversial,a review of existing studies on the use of dexamethasone for the prevention of acute mountain sickness was conducted,aiming to determine the best strategy.Possible mechanisms of protection against acute altitude illnesses are discussed based on the results of clinical trials.The data indicate that dexamethasone is most effective at altitudes above 4000 m at doses of 8–16 mg/d.Appropriately designed and powered trials are needed to obtain more evidence-based results on the dosage and timing of dexamethasone administration,and to provide optimized recommendations for the application of this powerful pharmacological tool.展开更多
This paper presents CMOS circuit designs of a ternary adder and a ternary multiplier,formulated using transmission function theory.Binary carry signals appearing in these designs allow conventional look-ahead carry te...This paper presents CMOS circuit designs of a ternary adder and a ternary multiplier,formulated using transmission function theory.Binary carry signals appearing in these designs allow conventional look-ahead carry techniques to be used.Compared with previous similar designs,the circuits proposed in this paper have advantages such as low dissipation,low output impedance,and simplicity of construction.展开更多
基金The Scientific Research Foundation for the Returned Overseas Chinese Scholars State Education Ministry(2002-2004)and Shaanxi Provincial Foreign Expert Bureau (2003).
文摘A review of the period of unregulated exploitation of forests in the state of West Virginia (U.S.) and in Shaanxi Province, PRC was presented. Economic and ecological recovery from exploitation has been different in the two regions due to basic differences in nature of the forest and in the degree and persistence of exploitive pressures. After a century since unregulated exploitation, West Virginia forests are well on the road to management for sustainability and conservation. Shaanxi's recovery from overuse and unregulated exploitation is less certain; forests are still in the early phases of ecological recovery there. Full recovery to a period of sustainability will take a century or longer. Suggestions are made for measures needed to enhance the forest recovery. Keywords Forests - Shaanxi - West Virginia - Central China - Forest exploitation - Recovery CLC number S754 Document code A Article ID 1007-662X(2004)01-0049-06 Foundation item: The project was sponsored by the Scientific Research Foundation for the Returned Overseas Chinese Scholars, State Education Ministry (2002–2004) and Shaanxi Provincial Foreign Expert Bureau (2003).Biography: Jack E. Coster (1935-), male, professor of West Virginia University, Morgantown, West Virginia. U.S.A.Responsible editor: Song Funan
基金Supported by the Financial from the U.S.Army Corps of Engineers-Lower Mississippi Valley Division,Vicksburg,Mississippi,U.S.A.
文摘The lower Mississippi River(LMR) has been heavily modified for multiple human purposes such as navigation, flood control, and bank stabilization. However, the LMR simultaneously supports a diverse fish fauna that includes recreational and commercial fisheries. Due to river training and diversion structures constructed during the past 80 years, the historic characteristics of the LMR have been drastically altered and have likely influenced fishes and fisheries in the system. One common restoration measure used throughout the LMR has been to "notch" wing-dike structures that close secondary(side) river channels. Dike notching allows year-round flows through secondary channels, which enhances habitat diversity and promotes biological productivity at the ecosystem scale. Although notching is presumed good for LMR fishes and other biota, few studies have examined its effects on fish assemblages. In this study, fish assemblages were sampled at seven LMR secondary channels spanning from river kilometer(rkm) 628(Louisiana-Mississippi, U.S.A.) upstream to rkm 1504(Missouri-Kentucky, U.S.A.). Four secondary channels were termed "permanent"(i.e.,with notched dikes) while three secondary channels were termed "temporary"(i.e., without notched dikes).Fishes were sampled by boat-mounted electrofishing conducted during falling and low stages from1995—1997. Fish assemblages differed between permanent and temporary secondary channels, and varied somewhat between falling and low stages. Gizzard shad(Dorosoma cepedianum), threadfin shad(D. petenense), and white bass(Morone chrysops) demonstrated consistent preferences for low-current conditions associated with temporary secondary channels. Conversely, blue catfish(Ictalurus furcatus), flathead catfish(Pylodictis olivaris), and freshwater drum(Aplodinotus grunniens) were more associated with permanent secondary channels. Future restoration strategies in the LMR should consider dike notching and resultant maintenance of permanent secondary channels in selected river reaches. However, temporary secondary channels also contain unique fish species, and also appear to be important sites of riverine primary production. Restoration strategies should consider a balance of both secondary channel types, which should support the greatest biodiversity for the LMR ecosystem.
文摘I offer suggestions to increase the probability of success of an international research project.Collaborative studies often produce more innovative and transformative scientific results than work done by a single investigator or an isolated team.My advice is intended for early-career scientists.The product of the collaboration may be high-impact research publications,enhanced geophysical monitoring capabilities in a foreign country,or an advanced training course.Choosing the right international partner is the most important step.Keeping an open mind and being receptive to suggestions to modify the initial concept is critical.Other key steps include having a mutually agreed upon plan with achievable goals and well-defined expected outcomes.International cooperation is a richly rewarding experience that accelerates progress in the Earth Sciences.
文摘When making assessments of forest resources,there is nearly ubiquitous interest in quantifying current status and trends in tree biomass and carbon stocks.While important at various spatial scales,typical estimations pertinent to broad forest management and policy issues are conducted for large areas such as state,regional,and national perspectives.These assessments are usually accomplished using large-area forest inventory data collected by National Forest Inventory(NFI)programs.While NFI efforts commonly collect size data for individual trees,there is often limited information for tree seedlings,e.g.,frequency by species.To fully describe the tree population across the entire range of sizes present,this study proposes methods to predict individual seedling groundline diameter and height using models developed from trees having a diameter at breast height(DBH)less than 7.62 cm.These attributes are subsequently used for the prediction of seedling stem volume,total aboveground biomass,and carbon content.The results suggest a smooth transition in tree attributes as size increases to where direct measurement of individual trees and prediction of their volume,biomass,and carbon are implemented as part of standard inventory protocols.Analyses including the full spectrum of tree sizes show that seedlings contribute roughly 0.6%–0.7%of the total tree volume/mass.This additional suite of information provides opportunities for more holistic assessments across the full spectrum of the tree resource or for specialized subdomains that include the seedling component.
基金Supported by National Natural Science Foundation of China(Grant No.12171140).
文摘It is well known that critical points of the total scalar curvature functional S on the space of all smooth Riemannian structures of volume 1 on a compact manifold M are exactly the Einstein metrics.When the domain of S is restricted to the space of constant scalar curvature metrics,there has been a conjecture that a critical point is also Einstein or isometric to a standard sphere.In the Riemannian case,it’s tangent space satisfies a decomposition.In this paper,we prove that if we only consider the Hermitian metrics,it also have a decomposition.Then we obtain the equation of the critical points among the Hermitian metrics.
基金supported by USDA-SCRI(Grant Nos.2017-51181-26830 and 2023-51181-41321)USDA-AMS SCMP(Grant No.16SCCMAR0001)+1 种基金Arkansas Department of Agriculture SCBGP(Grant No.AM22SCBGPAR1130-00)USDA NIFA Hatch project ARK0VG2018 and ARK02440.
文摘The Leafminers,representing a diverse group of insects from various genera within the Agromyzidae family,pose a significant threat to spinach(Spinacia oleracea L.)production.This study aimed to identify single nucleotide polymorphism(SNP)markers associated with leafminer resistance through a genome-wide association study(GWAS)and to evaluate the prediction accuracy(PA)for selecting resistant spinach using genomic prediction(GP).Using a dataset of 84301 SNPs obtained from whole-genome resequencing,seven GWAS models,including BLINK,FarmCPU,MLM,and MLMM in GAPIT 3,as well as MLM,GLM,and SMR in TASSEL 5,were employed to perform GWAS on a panel of 286 USDA spinach germplasm accessions.Three SNP markers,namely 1_115279256_C_T,3_157082529_C_T,and 4_168510908_T_G on chromosomes 1,3,and 4,respectively,were identified as associated with leafminer resistance.In the 30 kb flanking regions of these markers,four candidate genes(SOV1g031330,SOV1g031340,SOV4g047270,and SOV4g047280),encoding LOB domain-containing protein,KH domain-containing protein,were discovered.Nodulin-like domain-containing protein,and SAM domain-containing protein,were discovered.The PA for leafminer resistance selection was estimated using ten different SNP sets,including two GWAS-derived marker sets(three and 51 SNPs)and eight random marker sets(ranging from 51 to 10 K SNPs)analyzed by seven GP models.The findings emphasized the superior performance of GWAS-derived SNP sets,reaching a PA of up to 0.79 using the cBLUP model.Notably,this research marks the pioneering application of GP in the context of insect resistance,providing a significant advancement in the understanding and management of leafminer resistance in spinach cultivation.
文摘Acute exposure to high altitude can cause acute altitude illnesses and is associated with impaired cognitive and physical performance.The most effective preventive strategies currently recommended include environmental acclimatization(slow ascent and/or pre-acclimatization)or pharmacological support of acclimatization using acetazolamide.However,these strategies are not practical for high-altitude exposures that require rapid and unplanned ascent,high physical and mental performance,such as rescue missions or military operations.Dexamethasone and other modulators of the glucocorticoid system take effect quickly and are effective alternatives for preventing acute altitude illnesses when rapidly ascending to high altitudes.As the efficacy of dexamethasone in preventing acute mountain illnesses remains controversial,a review of existing studies on the use of dexamethasone for the prevention of acute mountain sickness was conducted,aiming to determine the best strategy.Possible mechanisms of protection against acute altitude illnesses are discussed based on the results of clinical trials.The data indicate that dexamethasone is most effective at altitudes above 4000 m at doses of 8–16 mg/d.Appropriately designed and powered trials are needed to obtain more evidence-based results on the dosage and timing of dexamethasone administration,and to provide optimized recommendations for the application of this powerful pharmacological tool.
基金Project supported by the National Natural Science Foundation of China.
文摘This paper presents CMOS circuit designs of a ternary adder and a ternary multiplier,formulated using transmission function theory.Binary carry signals appearing in these designs allow conventional look-ahead carry techniques to be used.Compared with previous similar designs,the circuits proposed in this paper have advantages such as low dissipation,low output impedance,and simplicity of construction.
