Wetlands have been noted to be beneficial worldwide. Despite wetlands being a natural asset that is of great significance to the human community, they are threatened by human and natural events. In Virunga National Pa...Wetlands have been noted to be beneficial worldwide. Despite wetlands being a natural asset that is of great significance to the human community, they are threatened by human and natural events. In Virunga National Park (VNP) wetlands are the habitat of Hippopotamus (<em>Hippopotamus amphibius</em>) which are among the animal species threatened by extinction in VNP since the past few decades. As shown by the last studies the number of Hippos population declined for 96% for the period of less than 40 years. This study evaluated landscape fragmentation status and its implication on the decline of the hippos population in VNP wetland for the period from 1990 to 2018. This study’s land cover data was obtained using remote sensing techniques with the help of software package ERDAS IMAGINE v16.6 and ArcGIS v10.3. It was mapped and classified using the maximum likelihood supervised classification technique. The landscape was classified into seven classes, which included Cropland, Forest, grassland, wetland, scrubland, bare area, and water. Satellite data (Landsat) was used to evaluate NDVI and NDWI and finally the landscape patterns in the study were analyzed using Fragstats 4.2, which was also used to calculate landscape indices for the respective periods. The results obtained from the LULC, NDVI, NDWI and the landscape metrics showed that during the period of our study the VNP wetland was fragmented. A strong negative correlation between the number of hippos and the wetland’s LFI (Landscape Fragmentation Index) values showed that wetland fragmentation was one of the reasons of the decline of Hippos in the park.展开更多
Hippopotamus bites are rare in medical consultations, despite several studies exposing their aggressive character. A case of a hippopotamus bite on the shoulder of a fisherman has been reported. In addition to the ost...Hippopotamus bites are rare in medical consultations, despite several studies exposing their aggressive character. A case of a hippopotamus bite on the shoulder of a fisherman has been reported. In addition to the osteoarticular aspect representing a therapeutic problem, the infectious aspect was marked by sepsis, with a death in less than 48 hours. Based on this observation, a protocol for the initial management of large animal bites was submitted.展开更多
Hippopotamidae is currently represented by the common hippo(Hippopotamus amphibius)and the pygmy one(Choeropsis liberiensis).Hippopotamus amphibius is a gregarious,social,and polygamous animal characterized by a semi-...Hippopotamidae is currently represented by the common hippo(Hippopotamus amphibius)and the pygmy one(Choeropsis liberiensis).Hippopotamus amphibius is a gregarious,social,and polygamous animal characterized by a semi-aquatic lifestyle,widely populating African fluvial and lacustrine systems.The common hippopotamus displays features such as high orbits on the cranial roof,high nostrils on the snout,webbed toes,and a complex skin adapted for an amphibious lifestyle(Lewison&Pluháˇcek 2017).Hippopotamus is characterized by a limited body size dimorphism(Shannon et al.2021)and is primarily a grazer,feeding largely on C4 plants(e.g.grass),but also including C3 plants in its diet(Cerling et al.2008).On the other hand,C.liberiensis is a solitary mammal,exhibiting nocturnal habits and adaptations for a more terrestrial environment,such as less webbed toes and low orbits(Eltringham 1999).Weston(2003)reported sexually dimorphic canines in C.liberiensis,with males exhibiting bigger tusks than females.展开更多
Effectively tuning the parameters of proportional-integralderivative(PID)controllers has persistently posed a challenge in control engineering.This study proposes enhanced hippopotamus optimization(EHO)to address this...Effectively tuning the parameters of proportional-integralderivative(PID)controllers has persistently posed a challenge in control engineering.This study proposes enhanced hippopotamus optimization(EHO)to address this challenge.Latin hypercube sampling and adaptive lens reverse learning are used to initialize the population to improve population diversity and enhance global search.Additionally,an adaptive perturbation mechanism is introduced into the position update in the exploration phase.To validate the performance of EHO,it is benchmarked against hippopotamus optimization and four classical or state-of-the-art intelligent algorithms using the CEC2022 test suite.The effectiveness of EHO is further evaluated by applying it in tuning PID controllers for different types of systems.The performance of EHO is compared with five other algorithms and the classical Ziegler-Nichols method.Analysis of convergence curves,step responses,box plots,and radar charts indicates that EHO outperforms the compared methods in accuracy,convergence speed,and stability.Finally,EHO is used to tune the cascade PID controller for trajectory tracking in a quadrotor unmanned aerial vehicle to assess its applicability.The simulation results indicate that the integrals of the time absolute error for the position channels(c,y,z),when the system is optimized using EHO over an 80 s runtime,are 59.979,22.162,and 0.017,respectively.These values are notably lower than those obtained by the original hippopotamus optimization and manual parameter adjustment.展开更多
In order to promote hippopotamus manage-ment in the captive and ex-situ environment,especially the control of behavioural and physiological status during breeding and lactation seasons,we conducted a prelimin-ary stud...In order to promote hippopotamus manage-ment in the captive and ex-situ environment,especially the control of behavioural and physiological status during breeding and lactation seasons,we conducted a prelimin-ary study on behavioural responses of a pair of hippos including both mother and infant in Hangzhou Wildlife Park,China.The study of the captive hippos for about 1-month in the lactation season was carried out during August and September,2009.The behavioural patterns were identified by all occurrence sampling and instanta-neous scanning sampling methods with 5–10 min inter-vals.As a result,mother-offspring conflicts and interactions did occur throughout the whole study period.Early maternal investment showed a positive trend in activity rhythms(slope=0.0014,Z=0.3027,P<0.001)and a negative trend(slope=–0.0066,Z=0.8807,P<0.001)in territorial occupation of water,all of which supported our hypotheses that the mother hippo might exert less care for the infant and cut down on her own obligations in nursing.For infant self-independence,during the whole lactation season,the primary trends of activities and territorial occupation dynamics of the infant hippo were slightly different from before,judging from linear models(slope=–0.0017,Z=0.3309,P<0.001).However,the frequencies of activities were not stable,especially at around 12 days of age.The trends of territorial occupation(slope=–0.0071,Z=0.904,P<0.001)also showed negative dynamics in water body occupation by the time the infant hippo grew up.The general trend(slope=–0.005,Z=0.06,P<0.001)of suckling dynamics was demonstrably negative,with an upwardsfluctuation at period 3(10–15th day).This also illustrated that as the infant developed,the dependency on the mother was reduced at the end of the lactation season.In addition,a sharp decline between P3 and P4 also supported the mother-offspring conflict theory.In general,time budgets of hippos in active behaviour were(31.8�2.1)%for the mother and(32.1�2.6)%for the infant.Spatial distribu-tions in water within temporal limitations were(80.1�2.7)%for the mother and(81.8�2.7)%for the infant.Behavioural dynamics showed strong synchronous relations between maternal investment and infant inde-pendence.Our current short-term investigation proves to be a key in management and conservation of hippopotami during the lactation season.展开更多
The pattern of population distribution of the common hippopotamus was examined along the 165 km stretch of the Luangwa River in eastern Zambia. The study area was divided between the upper (A-D) and lower (E-H) study ...The pattern of population distribution of the common hippopotamus was examined along the 165 km stretch of the Luangwa River in eastern Zambia. The study area was divided between the upper (A-D) and lower (E-H) study blocks. Population data are collected between 1976-2008 and this study 2009-2012 showed a significant difference in the pattern of density distribution between upper and lower study blocks. Upper blocks had higher density of 41/km than lower blocks 29/km. Length of study blocks was discounted as density was used to determine distribution pattern. Results obtained suggest that primary production in each study block as influenced by river geomorphologic features such as river bends and confluences characterized higher hippopotamus density in the upper blocks. Further research is required to investigate other factors that may have interplayed with food (above ground grass biomass) and river meander features to separate upper and lower blocks.展开更多
文摘Wetlands have been noted to be beneficial worldwide. Despite wetlands being a natural asset that is of great significance to the human community, they are threatened by human and natural events. In Virunga National Park (VNP) wetlands are the habitat of Hippopotamus (<em>Hippopotamus amphibius</em>) which are among the animal species threatened by extinction in VNP since the past few decades. As shown by the last studies the number of Hippos population declined for 96% for the period of less than 40 years. This study evaluated landscape fragmentation status and its implication on the decline of the hippos population in VNP wetland for the period from 1990 to 2018. This study’s land cover data was obtained using remote sensing techniques with the help of software package ERDAS IMAGINE v16.6 and ArcGIS v10.3. It was mapped and classified using the maximum likelihood supervised classification technique. The landscape was classified into seven classes, which included Cropland, Forest, grassland, wetland, scrubland, bare area, and water. Satellite data (Landsat) was used to evaluate NDVI and NDWI and finally the landscape patterns in the study were analyzed using Fragstats 4.2, which was also used to calculate landscape indices for the respective periods. The results obtained from the LULC, NDVI, NDWI and the landscape metrics showed that during the period of our study the VNP wetland was fragmented. A strong negative correlation between the number of hippos and the wetland’s LFI (Landscape Fragmentation Index) values showed that wetland fragmentation was one of the reasons of the decline of Hippos in the park.
文摘Hippopotamus bites are rare in medical consultations, despite several studies exposing their aggressive character. A case of a hippopotamus bite on the shoulder of a fisherman has been reported. In addition to the osteoarticular aspect representing a therapeutic problem, the infectious aspect was marked by sepsis, with a death in less than 48 hours. Based on this observation, a protocol for the initial management of large animal bites was submitted.
基金granted by the FCT-Fundação para a Ciência e a Tecnologia[2021.08458.BD],Erasmus+grant[29,191(532)105/2022/SMT],and SYNTHESYS+[DETAF-TA4-0632022]D.F.was supported by the Ayuda del Programa de Formación de Profesorado Universitario(FPU20/03,389)+2 种基金is a PhD student at the Programa de Doctorado en Biología at the Universidad Complutense de Madrid.This research was also supported by FCT,I.P.through the Research Unit UIDB/04,035/2020(https://doi.org/10.54499/UIDB/04035/2020)L.P.is granted by SYNTHESYS+[BE-TAF-136]This project is funded by the European Union-Next Generation EU,call PRIN PNRR project P2022RZ4PL.
文摘Hippopotamidae is currently represented by the common hippo(Hippopotamus amphibius)and the pygmy one(Choeropsis liberiensis).Hippopotamus amphibius is a gregarious,social,and polygamous animal characterized by a semi-aquatic lifestyle,widely populating African fluvial and lacustrine systems.The common hippopotamus displays features such as high orbits on the cranial roof,high nostrils on the snout,webbed toes,and a complex skin adapted for an amphibious lifestyle(Lewison&Pluháˇcek 2017).Hippopotamus is characterized by a limited body size dimorphism(Shannon et al.2021)and is primarily a grazer,feeding largely on C4 plants(e.g.grass),but also including C3 plants in its diet(Cerling et al.2008).On the other hand,C.liberiensis is a solitary mammal,exhibiting nocturnal habits and adaptations for a more terrestrial environment,such as less webbed toes and low orbits(Eltringham 1999).Weston(2003)reported sexually dimorphic canines in C.liberiensis,with males exhibiting bigger tusks than females.
基金Project supported by the National Natural Science Foundation of China(Nos.62341303,62203132,and 52265066)the Guizhou Provincial Science and Technology Projects(No.[ZK[2022]Yiban103])the Guizhou Science and Technology Support Plan(No.2024 General 136)。
文摘Effectively tuning the parameters of proportional-integralderivative(PID)controllers has persistently posed a challenge in control engineering.This study proposes enhanced hippopotamus optimization(EHO)to address this challenge.Latin hypercube sampling and adaptive lens reverse learning are used to initialize the population to improve population diversity and enhance global search.Additionally,an adaptive perturbation mechanism is introduced into the position update in the exploration phase.To validate the performance of EHO,it is benchmarked against hippopotamus optimization and four classical or state-of-the-art intelligent algorithms using the CEC2022 test suite.The effectiveness of EHO is further evaluated by applying it in tuning PID controllers for different types of systems.The performance of EHO is compared with five other algorithms and the classical Ziegler-Nichols method.Analysis of convergence curves,step responses,box plots,and radar charts indicates that EHO outperforms the compared methods in accuracy,convergence speed,and stability.Finally,EHO is used to tune the cascade PID controller for trajectory tracking in a quadrotor unmanned aerial vehicle to assess its applicability.The simulation results indicate that the integrals of the time absolute error for the position channels(c,y,z),when the system is optimized using EHO over an 80 s runtime,are 59.979,22.162,and 0.017,respectively.These values are notably lower than those obtained by the original hippopotamus optimization and manual parameter adjustment.
基金supported by Zhejiang Provincial Natural Science Foundation of China(No.Y3090613)Key Project of Zhejiang Provincial Education Department of China(No.Z200906965).
文摘In order to promote hippopotamus manage-ment in the captive and ex-situ environment,especially the control of behavioural and physiological status during breeding and lactation seasons,we conducted a prelimin-ary study on behavioural responses of a pair of hippos including both mother and infant in Hangzhou Wildlife Park,China.The study of the captive hippos for about 1-month in the lactation season was carried out during August and September,2009.The behavioural patterns were identified by all occurrence sampling and instanta-neous scanning sampling methods with 5–10 min inter-vals.As a result,mother-offspring conflicts and interactions did occur throughout the whole study period.Early maternal investment showed a positive trend in activity rhythms(slope=0.0014,Z=0.3027,P<0.001)and a negative trend(slope=–0.0066,Z=0.8807,P<0.001)in territorial occupation of water,all of which supported our hypotheses that the mother hippo might exert less care for the infant and cut down on her own obligations in nursing.For infant self-independence,during the whole lactation season,the primary trends of activities and territorial occupation dynamics of the infant hippo were slightly different from before,judging from linear models(slope=–0.0017,Z=0.3309,P<0.001).However,the frequencies of activities were not stable,especially at around 12 days of age.The trends of territorial occupation(slope=–0.0071,Z=0.904,P<0.001)also showed negative dynamics in water body occupation by the time the infant hippo grew up.The general trend(slope=–0.005,Z=0.06,P<0.001)of suckling dynamics was demonstrably negative,with an upwardsfluctuation at period 3(10–15th day).This also illustrated that as the infant developed,the dependency on the mother was reduced at the end of the lactation season.In addition,a sharp decline between P3 and P4 also supported the mother-offspring conflict theory.In general,time budgets of hippos in active behaviour were(31.8�2.1)%for the mother and(32.1�2.6)%for the infant.Spatial distribu-tions in water within temporal limitations were(80.1�2.7)%for the mother and(81.8�2.7)%for the infant.Behavioural dynamics showed strong synchronous relations between maternal investment and infant inde-pendence.Our current short-term investigation proves to be a key in management and conservation of hippopotami during the lactation season.
文摘The pattern of population distribution of the common hippopotamus was examined along the 165 km stretch of the Luangwa River in eastern Zambia. The study area was divided between the upper (A-D) and lower (E-H) study blocks. Population data are collected between 1976-2008 and this study 2009-2012 showed a significant difference in the pattern of density distribution between upper and lower study blocks. Upper blocks had higher density of 41/km than lower blocks 29/km. Length of study blocks was discounted as density was used to determine distribution pattern. Results obtained suggest that primary production in each study block as influenced by river geomorphologic features such as river bends and confluences characterized higher hippopotamus density in the upper blocks. Further research is required to investigate other factors that may have interplayed with food (above ground grass biomass) and river meander features to separate upper and lower blocks.
