The maintenance and restoration of wetland habitat is a priority conservation action for most waterfowl and other wetland-dependent species in North America.Despite much progress in targeting habitat management in sta...The maintenance and restoration of wetland habitat is a priority conservation action for most waterfowl and other wetland-dependent species in North America.Despite much progress in targeting habitat management in staging and wintering areas,methods to identify and target high-quality breeding habitats that result in the greatest potential for wildlife are still required.This is particularly true for species that breed in remote,inaccessible areas such as the American black duck,an intensively managed game bird in Eastern North America.Although evidence suggests that black ducks prefer productive,nutrient-rich waterbodies,such as beaver ponds,information about the distribution and quality of these habitats across the vast boreal forest is lacking with accurate identification remaining a challenge.Continuing advancements in remote sensing technologies that provide spatially extensive and temporally repeated information are particularly useful in meeting this information gap.In this study,we used multi-source remotely sensed information and a fuzzy analytical hierarchy process to map the spatial distribution of beaver ponds in Ontario.The use of multi-source data,including a Digital Elevation Model,a Sentinel-2 Multi-Spectral Image,and RadarSat 2 Polarimetric data,enabled us to identify individual beaver ponds on the landscape.Our model correctly identified an average of 83.0%of the known beaver dams and 72.5%of the known beaver ponds based on validation with an independent dataset.This study demonstrates that remote sensing is an effective approach for identifying beaver-modified wetland features and can be applied to map these and other wetland habitat features of interest across large spatial extents.Furthermore,the systematic acquisition strategy of the remote sensors employed is well suited for monitoring changes in wetland conditions that affect the availability of habitats important to waterfowl and other wildlife.展开更多
In this paper, we consider the mixed Navier-Stokes/Darcy model with BeaversJoseph interface conditions. Based on two-grid discretizations, a local and parallel finite element algorithm for this mixed model is proposed...In this paper, we consider the mixed Navier-Stokes/Darcy model with BeaversJoseph interface conditions. Based on two-grid discretizations, a local and parallel finite element algorithm for this mixed model is proposed and analyzed. Optimal errors are obtained and numerical experiments are presented to show the efficiency and effectiveness of the local and parallel finite element algorithm.展开更多
The European beaver (Castor fiber L.) is the largest free-living rode nt in Eurasia. The prese nt work aimed to determi ne sex- and seas on-related cha nges in leptin receptor (Ob-R) expression in the hypothalamic-pit...The European beaver (Castor fiber L.) is the largest free-living rode nt in Eurasia. The prese nt work aimed to determi ne sex- and seas on-related cha nges in leptin receptor (Ob-R) expression in the hypothalamic-pituitary-gonadal/adrenal axes and uterus of beavers during breeding-(April), postbreeding-(July), and pre-breeding-(November) periods. The expression of Ob-R gene and protein was found in all analyzed tissues. The expression of Ob-R mRNA remained constant in the hypothalamus of both sexes during the analyzed stages. Sex- and season-related changes were found in the pituitary gland;the greatest level was observed in July in both sexes. The same expression pattern was noted in the testis, whereas in the ovary a lack of seasonal changes was found. In uterine tissues, the greatest expression occurred in November. The impact of season was also demonstrated in the adrenal cortex. In females, a higher Ob-R transcript level was noted in April, while in males, an increased mRNA abundanee was noted in November than July. Our study suggests that in the beaver, leptin acting via the Ob-R can be an important endocrine factor engaged in the regulation of reproductive functions and stress response.展开更多
Recent studies show an increase in the population of beavers, nutria and other rodents in vast regions of central Europe over the last 15 years. Unfortunately, this caused in many instances considerable damage on larg...Recent studies show an increase in the population of beavers, nutria and other rodents in vast regions of central Europe over the last 15 years. Unfortunately, this caused in many instances considerable damage on large rivers along dykes and earthworks in the floodplain areas, leading to an increased risk of bank failures. However, most of these mammals belong to protected species. This work is aimed at showing positive experience in cooperation with universities, research institutes and environmental agencies regarding measures to permanently safeguard the banks using composite erosion control systems with polymer coated steel wire net （as flexible reinforcement component） and a geosynthetic （to promote vegetation growth）. The steel mesh component works as an effective long-term barrier against the intrusion of mammals, discouraging them from digging inside the core of the dyke. An analysis of the sensitive areas to be protected led also to definition of the characteristics of these interventions （length, shape, escape ways, population areas, etc.）. The study will present several additional benefits when using polymer steel nets along dykes, such as： high and durable erosion protection in overflow areas, promotion of fast and effective vegetation growth （increasing stability）, surface protection against ice impacts （in northern regions）, ease of installation, maintenance, ability to conform to irregular shapes of the slope. This work will also present the positive outcome of research studies along dykes in Germany, Austria and in Italy.展开更多
Objective: To report a case of beaver tail liver accidentally discovered by preoperative examination, and review relevant literature to improve the understanding of the anatomical variation of the liver. Methods: Anal...Objective: To report a case of beaver tail liver accidentally discovered by preoperative examination, and review relevant literature to improve the understanding of the anatomical variation of the liver. Methods: Analysis of a case of beaver tail liver incidentally discovered during preoperative examination for hepatic abscess in our hospital in June 2023. Combining domestic and foreign literature, the etiology, clinical manifestations, diagnosis, differential diagnosis, and treatment of beaver tail liver are discussed. Results: The patient was admitted due to abdominal pain and fever, with no other specific discomfort. An incidental finding of a beaver tail liver was discovered during imaging examinations. Conclusion: The beaver tail liver is a variant in hepatic anatomical morphology with nonspecific clinical manifestations. It is often incidentally discovered through imaging examinations such as ultrasound, CT, or MRI. Treatment is only necessary when the beaver tail liver is associated with hepatitis or tumors;otherwise, it does not require specific treatment.展开更多
PURPOSE. To investigate a potential genetic contribution to intraocular pressure (IOP), we performed a complex segregation analysis on 2337 individuals in 620 extended pedigrees ascertained through a population- based...PURPOSE. To investigate a potential genetic contribution to intraocular pressure (IOP), we performed a complex segregation analysis on 2337 individuals in 620 extended pedigrees ascertained through a population- based cohort, the Beaver Dam Eye Study (BDES). IOP is a principal risk factor for primary open- angle glaucoma (POAG) a leading cause of blindness worldwide. METHODS. Segregation analysis is an analytical method that provides statistical evidence supporting the involvement of a major gene or polygenes in a particular phenotype. Detailed medical histories and eye examinations were performed on all participants. From the two eyes, the higher IOP measurement was used as a continuous trait after adjustment for covariates. Agenome- wide scan(GWS) using affected sib pair linkage analysis was performed on 218 sibling pairs. RESULTS. In this segregation analysis the model that allowed for an unmeasured major environmental effect plus a polygenic/ multifactorial effect provided the best fit and was the most parsimonious model. The lack of an adequate fit for the Mendelian single- gene models is consistent with a multifactorial model of inheritance that may include multiple genes and environmental factors that contribute to IOP. The results of the GWS yielded two novel loci as potential linkage regions for IOP on chromosomes 6 (P=0.008) and 13 (P=0.0007). Neither of these regions has previously been identified in GWS of POAG. CONCLUSIONS. The segregation and familial correlation analyses of IOP suggest a polygenetic component with environmental influences. The pilot linkage study further con- firms the heterogeneity of IOP with the identification of two novel genetic loci.展开更多
PURPOSE: To examine the association between presence,severity,and extent of lesions of age-related macular degeneration (AMD) and optic disk and cup diameters in a general population. DESIGN: Cross-sectional study. ME...PURPOSE: To examine the association between presence,severity,and extent of lesions of age-related macular degeneration (AMD) and optic disk and cup diameters in a general population. DESIGN: Cross-sectional study. MET-HODS: setting: Population-based. study population: Adults aged 43 to 86 years participating in the Beaver Dam Eye Study. observation procedures: Fundus photographs were graded for lesions of AMD using standard protocols. The photographs were obtained during the baseline examination of the Beaver Dam Eye Study. main outcome measure: Optic disk cupping as related to presence,severity,and extent of lesions of AMD. RESULTS: There were no significant differences in the vertical optic disk and cup measurements or in the vertical cup to disk ratios by severity of lesions of AMD (P values all greater than .10). In those eyes with late lesions of AMD,there was no association of the size of the lesions or their distribution in the fundus and the extent of cupping. CONCLUSIONS: From a population perspective,there is no relationship of the presence or severity of AMD and optic disk cupping.展开更多
PURPOSE. To describe familial correlations of retinal vessel measurements. METHODS. A standardized examination and interview was administered to a population- based cohort of adults aged 43- 86 years. Blood pressure w...PURPOSE. To describe familial correlations of retinal vessel measurements. METHODS. A standardized examination and interview was administered to a population- based cohort of adults aged 43- 86 years. Blood pressure was measured, and family relationships, current smoking status, and photographs of the retina were obtained. Computer- assisted grading was done to determine central retinal arteriole (CRAE) and venule equivalents (CRVE), and the arteriole- to- venule ratio (AVR)- was computed. Familial correlations were calculated using FCOR in the SAGE software package. Analysis was done on the right eye measures for 871 sibling, 341 parent- child, 1362 cousin, 554 avuncular, and 887 spousal pairs. RESULTS. After adjustment for age, gender, mean arterial blood pressure, and current smoking status, the correlations (and 95% confidence interval) between siblings for the CRVE, CRAE,and AVR were 0.23 (0.16, 0.31), 0.20 (0.12, 0.28) and 0.13 (0.05, 0.20), respectively. Parent- child correlations were very similar, and the avuncular correlations were about half as great. The cousin correlations were about half the avuncular correlations. Spousal correlations of 0.03, 0.04, and 0.01 for CRVE, CRAJE, and AVR, respectively, were not significantly different from 0. CONCLUSIONS. Retinal vessel equivalents were more highly correlated between relatives than between unrelated individuals. The relative magnitudes of these correlations were likely the result of shared genes. Because the vessel measurements have been shown to be predictive of cardiovascular and other systemic diseases, understanding the determinants of these familial relationships could have important health benefits.展开更多
Objective: To investigate the relationship of age-related maculopathy,cataract,glaucoma,visual impairment,and diabetic retinopathy to survival during a 14-year period. Methods: Persons ranging in age from 43 to 84 yea...Objective: To investigate the relationship of age-related maculopathy,cataract,glaucoma,visual impairment,and diabetic retinopathy to survival during a 14-year period. Methods: Persons ranging in age from 43 to 84 years in the period from September 15,1987,to May 4,1988,participated in the baseline examination of the population-based Beaver Dam Eye Study (n=4926). Standardized protocols,including photography,were used to determine the presence of ocular disease. Survival was followed using standardized protocols. Results: As of December 31,2002,32% of the baseline population had died (median follow-up,13.2 years). After adjusting for age,sex,and systemic and lifestyle factors,poorer survival was associated with cortical cataract (hazard ratio HR,1.21; 95% confidence interval CI,1.06-1.37),any cataract (HR,1.16; 95% CI,1.03-1.32),diabetic retinopathy (HR per 1-step increase in 4-level severity,1.36; 95% CI,1.14-1.63),and visual impairment (HR,1.24; 95% CI,1.04-1.48) and marginally associated with increasing severity of nuclear sclerosis (HR,1.07;95% CI,0.99-1.16). Age-related maculopathy and glaucoma were not associated with poorer survival. Associations tended to be slightly stronger in men than women. Conclusions: Cataract,diabetic retinopathy,and visual impairment were associated with poorer survival and not explained by traditional risk factors for mortality. These ocular conditions may serve as markers for mortality in the general population.展开更多
Eight fatty acids from beaver oil were identified by GC-9A, and their contents were determinded. A simple yet effective method for separation and quantification was described. Contents of the fatty acids were related ...Eight fatty acids from beaver oil were identified by GC-9A, and their contents were determinded. A simple yet effective method for separation and quantification was described. Contents of the fatty acids were related to their conditions of extraction.展开更多
There are many locations in Russia where Eurasian beaver(Castor fiber)populations have been restored.As a keystone species,beavers provide wide-ranging direct and indirect impacts on aquatic ecosystems.In particular,b...There are many locations in Russia where Eurasian beaver(Castor fiber)populations have been restored.As a keystone species,beavers provide wide-ranging direct and indirect impacts on aquatic ecosystems.In particular,beaver-created ponds are sites for spawning and nursery places for tadpoles of the brown frogs(genus Rana).Because of such impacts,study techniques for assessing aquatic organism abundance are being developed.We compared two methods for estimating tadpole abundance:traditional catches by dipnet and electrofishing.Our results show that the dipnet catch data for the shallower ponds with larger water surface area were five times lower than that obtained by electrofishing.Therefore,we conclude that dipnet catches are not suitable for comparing the relative abundance of tadpoles in the two beaver ponds that were studied.展开更多
基金supported by the Natural Sciences and Engineering Research Council of Canada[RGPIN-2021-03624].
文摘The maintenance and restoration of wetland habitat is a priority conservation action for most waterfowl and other wetland-dependent species in North America.Despite much progress in targeting habitat management in staging and wintering areas,methods to identify and target high-quality breeding habitats that result in the greatest potential for wildlife are still required.This is particularly true for species that breed in remote,inaccessible areas such as the American black duck,an intensively managed game bird in Eastern North America.Although evidence suggests that black ducks prefer productive,nutrient-rich waterbodies,such as beaver ponds,information about the distribution and quality of these habitats across the vast boreal forest is lacking with accurate identification remaining a challenge.Continuing advancements in remote sensing technologies that provide spatially extensive and temporally repeated information are particularly useful in meeting this information gap.In this study,we used multi-source remotely sensed information and a fuzzy analytical hierarchy process to map the spatial distribution of beaver ponds in Ontario.The use of multi-source data,including a Digital Elevation Model,a Sentinel-2 Multi-Spectral Image,and RadarSat 2 Polarimetric data,enabled us to identify individual beaver ponds on the landscape.Our model correctly identified an average of 83.0%of the known beaver dams and 72.5%of the known beaver ponds based on validation with an independent dataset.This study demonstrates that remote sensing is an effective approach for identifying beaver-modified wetland features and can be applied to map these and other wetland habitat features of interest across large spatial extents.Furthermore,the systematic acquisition strategy of the remote sensors employed is well suited for monitoring changes in wetland conditions that affect the availability of habitats important to waterfowl and other wildlife.
文摘In this paper, we consider the mixed Navier-Stokes/Darcy model with BeaversJoseph interface conditions. Based on two-grid discretizations, a local and parallel finite element algorithm for this mixed model is proposed and analyzed. Optimal errors are obtained and numerical experiments are presented to show the efficiency and effectiveness of the local and parallel finite element algorithm.
文摘The European beaver (Castor fiber L.) is the largest free-living rode nt in Eurasia. The prese nt work aimed to determi ne sex- and seas on-related cha nges in leptin receptor (Ob-R) expression in the hypothalamic-pituitary-gonadal/adrenal axes and uterus of beavers during breeding-(April), postbreeding-(July), and pre-breeding-(November) periods. The expression of Ob-R gene and protein was found in all analyzed tissues. The expression of Ob-R mRNA remained constant in the hypothalamus of both sexes during the analyzed stages. Sex- and season-related changes were found in the pituitary gland;the greatest level was observed in July in both sexes. The same expression pattern was noted in the testis, whereas in the ovary a lack of seasonal changes was found. In uterine tissues, the greatest expression occurred in November. The impact of season was also demonstrated in the adrenal cortex. In females, a higher Ob-R transcript level was noted in April, while in males, an increased mRNA abundanee was noted in November than July. Our study suggests that in the beaver, leptin acting via the Ob-R can be an important endocrine factor engaged in the regulation of reproductive functions and stress response.
文摘Recent studies show an increase in the population of beavers, nutria and other rodents in vast regions of central Europe over the last 15 years. Unfortunately, this caused in many instances considerable damage on large rivers along dykes and earthworks in the floodplain areas, leading to an increased risk of bank failures. However, most of these mammals belong to protected species. This work is aimed at showing positive experience in cooperation with universities, research institutes and environmental agencies regarding measures to permanently safeguard the banks using composite erosion control systems with polymer coated steel wire net （as flexible reinforcement component） and a geosynthetic （to promote vegetation growth）. The steel mesh component works as an effective long-term barrier against the intrusion of mammals, discouraging them from digging inside the core of the dyke. An analysis of the sensitive areas to be protected led also to definition of the characteristics of these interventions （length, shape, escape ways, population areas, etc.）. The study will present several additional benefits when using polymer steel nets along dykes, such as： high and durable erosion protection in overflow areas, promotion of fast and effective vegetation growth （increasing stability）, surface protection against ice impacts （in northern regions）, ease of installation, maintenance, ability to conform to irregular shapes of the slope. This work will also present the positive outcome of research studies along dykes in Germany, Austria and in Italy.
文摘Objective: To report a case of beaver tail liver accidentally discovered by preoperative examination, and review relevant literature to improve the understanding of the anatomical variation of the liver. Methods: Analysis of a case of beaver tail liver incidentally discovered during preoperative examination for hepatic abscess in our hospital in June 2023. Combining domestic and foreign literature, the etiology, clinical manifestations, diagnosis, differential diagnosis, and treatment of beaver tail liver are discussed. Results: The patient was admitted due to abdominal pain and fever, with no other specific discomfort. An incidental finding of a beaver tail liver was discovered during imaging examinations. Conclusion: The beaver tail liver is a variant in hepatic anatomical morphology with nonspecific clinical manifestations. It is often incidentally discovered through imaging examinations such as ultrasound, CT, or MRI. Treatment is only necessary when the beaver tail liver is associated with hepatitis or tumors;otherwise, it does not require specific treatment.
文摘PURPOSE. To investigate a potential genetic contribution to intraocular pressure (IOP), we performed a complex segregation analysis on 2337 individuals in 620 extended pedigrees ascertained through a population- based cohort, the Beaver Dam Eye Study (BDES). IOP is a principal risk factor for primary open- angle glaucoma (POAG) a leading cause of blindness worldwide. METHODS. Segregation analysis is an analytical method that provides statistical evidence supporting the involvement of a major gene or polygenes in a particular phenotype. Detailed medical histories and eye examinations were performed on all participants. From the two eyes, the higher IOP measurement was used as a continuous trait after adjustment for covariates. Agenome- wide scan(GWS) using affected sib pair linkage analysis was performed on 218 sibling pairs. RESULTS. In this segregation analysis the model that allowed for an unmeasured major environmental effect plus a polygenic/ multifactorial effect provided the best fit and was the most parsimonious model. The lack of an adequate fit for the Mendelian single- gene models is consistent with a multifactorial model of inheritance that may include multiple genes and environmental factors that contribute to IOP. The results of the GWS yielded two novel loci as potential linkage regions for IOP on chromosomes 6 (P=0.008) and 13 (P=0.0007). Neither of these regions has previously been identified in GWS of POAG. CONCLUSIONS. The segregation and familial correlation analyses of IOP suggest a polygenetic component with environmental influences. The pilot linkage study further con- firms the heterogeneity of IOP with the identification of two novel genetic loci.
文摘PURPOSE: To examine the association between presence,severity,and extent of lesions of age-related macular degeneration (AMD) and optic disk and cup diameters in a general population. DESIGN: Cross-sectional study. MET-HODS: setting: Population-based. study population: Adults aged 43 to 86 years participating in the Beaver Dam Eye Study. observation procedures: Fundus photographs were graded for lesions of AMD using standard protocols. The photographs were obtained during the baseline examination of the Beaver Dam Eye Study. main outcome measure: Optic disk cupping as related to presence,severity,and extent of lesions of AMD. RESULTS: There were no significant differences in the vertical optic disk and cup measurements or in the vertical cup to disk ratios by severity of lesions of AMD (P values all greater than .10). In those eyes with late lesions of AMD,there was no association of the size of the lesions or their distribution in the fundus and the extent of cupping. CONCLUSIONS: From a population perspective,there is no relationship of the presence or severity of AMD and optic disk cupping.
文摘PURPOSE. To describe familial correlations of retinal vessel measurements. METHODS. A standardized examination and interview was administered to a population- based cohort of adults aged 43- 86 years. Blood pressure was measured, and family relationships, current smoking status, and photographs of the retina were obtained. Computer- assisted grading was done to determine central retinal arteriole (CRAE) and venule equivalents (CRVE), and the arteriole- to- venule ratio (AVR)- was computed. Familial correlations were calculated using FCOR in the SAGE software package. Analysis was done on the right eye measures for 871 sibling, 341 parent- child, 1362 cousin, 554 avuncular, and 887 spousal pairs. RESULTS. After adjustment for age, gender, mean arterial blood pressure, and current smoking status, the correlations (and 95% confidence interval) between siblings for the CRVE, CRAE,and AVR were 0.23 (0.16, 0.31), 0.20 (0.12, 0.28) and 0.13 (0.05, 0.20), respectively. Parent- child correlations were very similar, and the avuncular correlations were about half as great. The cousin correlations were about half the avuncular correlations. Spousal correlations of 0.03, 0.04, and 0.01 for CRVE, CRAJE, and AVR, respectively, were not significantly different from 0. CONCLUSIONS. Retinal vessel equivalents were more highly correlated between relatives than between unrelated individuals. The relative magnitudes of these correlations were likely the result of shared genes. Because the vessel measurements have been shown to be predictive of cardiovascular and other systemic diseases, understanding the determinants of these familial relationships could have important health benefits.
文摘Objective: To investigate the relationship of age-related maculopathy,cataract,glaucoma,visual impairment,and diabetic retinopathy to survival during a 14-year period. Methods: Persons ranging in age from 43 to 84 years in the period from September 15,1987,to May 4,1988,participated in the baseline examination of the population-based Beaver Dam Eye Study (n=4926). Standardized protocols,including photography,were used to determine the presence of ocular disease. Survival was followed using standardized protocols. Results: As of December 31,2002,32% of the baseline population had died (median follow-up,13.2 years). After adjusting for age,sex,and systemic and lifestyle factors,poorer survival was associated with cortical cataract (hazard ratio HR,1.21; 95% confidence interval CI,1.06-1.37),any cataract (HR,1.16; 95% CI,1.03-1.32),diabetic retinopathy (HR per 1-step increase in 4-level severity,1.36; 95% CI,1.14-1.63),and visual impairment (HR,1.24; 95% CI,1.04-1.48) and marginally associated with increasing severity of nuclear sclerosis (HR,1.07;95% CI,0.99-1.16). Age-related maculopathy and glaucoma were not associated with poorer survival. Associations tended to be slightly stronger in men than women. Conclusions: Cataract,diabetic retinopathy,and visual impairment were associated with poorer survival and not explained by traditional risk factors for mortality. These ocular conditions may serve as markers for mortality in the general population.
文摘Eight fatty acids from beaver oil were identified by GC-9A, and their contents were determinded. A simple yet effective method for separation and quantification was described. Contents of the fatty acids were related to their conditions of extraction.
基金supported by the Russian Foundation for Basic Research,project numbers 15-29-02550 ofi_m and 16-34-00119 mol_a.
文摘There are many locations in Russia where Eurasian beaver(Castor fiber)populations have been restored.As a keystone species,beavers provide wide-ranging direct and indirect impacts on aquatic ecosystems.In particular,beaver-created ponds are sites for spawning and nursery places for tadpoles of the brown frogs(genus Rana).Because of such impacts,study techniques for assessing aquatic organism abundance are being developed.We compared two methods for estimating tadpole abundance:traditional catches by dipnet and electrofishing.Our results show that the dipnet catch data for the shallower ponds with larger water surface area were five times lower than that obtained by electrofishing.Therefore,we conclude that dipnet catches are not suitable for comparing the relative abundance of tadpoles in the two beaver ponds that were studied.
