Perching allows small Unmanned Aerial Vehicles(UAVs)to maintain their altitude while significantly extending their flight duration and reducing noise.However,current research on flying habitats is poorly adapted to un...Perching allows small Unmanned Aerial Vehicles(UAVs)to maintain their altitude while significantly extending their flight duration and reducing noise.However,current research on flying habitats is poorly adapted to unstructured environments,and lacks autonomous capabilities,requiring ideal experimental environments and remote control by personnel.To solve these problems,in this paper,we propose a bat-like UAV perching mechanism by investigating the bat upside-down perching method,which realizes double self-locking in the perching state using the ratchet and four-link dead point mechanisms.Based on this perching mechanism,this study proposes a control strategy for UAVs to track targets and accomplish flight perching autonomously by combining a binocular camera,single-point LiDAR,and pressure sensors.Autonomous perching experiments were conducted for crossbar-type objects outdoors.The experimental results show that a multirotor UAV equipped with the perching mechanism and sensors can reliably achieve autonomous flight perching and re-flying off the target outdoors.The power consumption is reduced to 2.9%of the hovering state when perched on the target object.展开更多
The mineral stability and solute activities of soil solution extracted from selected horizons of seven studied pedons of Alfisols in Kentucky, USA, and the relationship between distribution of iron-manganese concretio...The mineral stability and solute activities of soil solution extracted from selected horizons of seven studied pedons of Alfisols in Kentucky, USA, and the relationship between distribution of iron-manganese concretions and the restrictive layers were investigated. The results showed that the genesis and development of these soils and mineral weathering trends were strongly influenced by the depth of bedrock and the presence of perched water tables at lithic (limestone) interfaces due to the dissolution and buffering effect of limestone bedrock. The extractable Mg/Ca ratio as depth function and soil depth above bedrock could be used as indices of weathering and degree of soil development. Maximum iron-manganese concretion accumulation was found to occur in the horizon overlying clay horizon (>40% clay) with a sharp increase in clay content (>10%), which suggested that zones of Fe-Mn concretion accumulation in soils of the Inner Bluegrass Region appeared to be a sensitive genetic indicator of argillic horizons with restrictive permeability.展开更多
Energy consumption and acoustic noise can be significantly reduced through perching in the sustained flights of small Unmanned Aerial Vehicles(UAVs).However,the existing flying perching robots lack good adaptability o...Energy consumption and acoustic noise can be significantly reduced through perching in the sustained flights of small Unmanned Aerial Vehicles(UAVs).However,the existing flying perching robots lack good adaptability or loading capacity in unstructured environments.Aiming at solving these problems,a deformable UAV perching mechanism with strong adaptability and high loading capacity,which is inspired by the structure and movements of birds'feet,is presented in this paper.Three elastic toes,an inverted crank slider mechanism used to realize the opening and closing movements,and a gear mechanism used to deform between two configurations are included in this mechanism.With experiments on its performance towards different objects,Results show that it can perch on various objects reliably,and its payload is more than 15 times its weight.By integrating it with a quadcopter,it can perch on different types of targets in outdoor environments,such as tree branches,cables,eaves,and spherical lamps.In addition,the energy consumption of the UAV perching system when perching on objects can be reduced to 0.015 times that of hovering.展开更多
The key to high manoeuvre ability in bird flight lies in the combined morphing of wings and tail.The perching of a wild Haliaeetus Albicilla without running or wing flapping is recorded and investigated using a high-s...The key to high manoeuvre ability in bird flight lies in the combined morphing of wings and tail.The perching of a wild Haliaeetus Albicilla without running or wing flapping is recorded and investigated using a high-speed digital video.A shape reconstruction method is proposed to describe wing contours and tail contours during perching.The avian airfoil geometries of the Aquila Chrysaetos are extracted from noncontact surface measurements using a ROMBER 3D laser scanner.The wing planform,chord distribution and twist distribution are fitted in convenient analytical expressions to obtain a 3D wing geometry.A three-jointed arm model is proposed to associate with the 3D wing geometry,while a one-joint arm model is proposed to describe the kinematics of tail.Therefore,a 3D bird model is established.The perching sequences of the wild eagle are recaptured and regenerated with the proposed 3D bird model.A quasi-steady aerodynamic model is applied in the aerodynamic predictions,a four-step Adams-Bashforth method is used to calculate the ordinary differential equations,thus a BFGS based optimization method is established to predict the perching motions.展开更多
The technology of homology cloning and anchored PCR was used to clone the IL-1β gene from the Japanese sea perch （Lateolabrax iaponicus）. The full-length cDNA of sea perch IL-1β was 1 310 bp, including a 5＇ untra...The technology of homology cloning and anchored PCR was used to clone the IL-1β gene from the Japanese sea perch （Lateolabrax iaponicus）. The full-length cDNA of sea perch IL-1β was 1 310 bp, including a 5＇ untranslated regiop （UTR） of 136 bp, a 3＇ UTR ot 430 bp, and an ORF of 774 bp encoding a polypeptide of 258 amino acids with an estimated molecular mass of 29.31 kDa. The searches for nucleotides and protein sequence similarities with the BLAST analysis indicated that the deduced amino acid sequence of sea perch IL-1β was homological to the IL-1β in other fish species and even the mammalian. Conserved signature sequences of the IL-1β gene family were found in the sea perch IL-1β deduced amino acid sequence. Temporal expressions of the IL-1β gene in LPS or iridovirus challenged group and in control group were measured by the semi-quantitative RT-PCR. The mRNA transcripts of IL-1β could be detected in head-kidney, spleen, liver, gill and heart of the healthy individuals, and the expression level of IL-1β in head-kidney, spleen and gill was higher than that in liver and heart, but it was hard to be detected in the brain. After being stimulated by the LPS or iridovirus, the IL-1β expression in most of examined tissues was up-regulated, and also could be detected in the brain. These results indicated that the expression of sea perch IL-1β was constitutive and could be up-regulated by immune effector stimulation. Therefore the sea perch IL-1β could play a critical role in the host-pathogen interaction.展开更多
Fish maw(the dried swimbladders of fish) is ranked in the list of the four sea treasures in Chinese cuisine. Fish maw is mainly produced from croaker, which is the most highly priced. However, some of the fish maw bei...Fish maw(the dried swimbladders of fish) is ranked in the list of the four sea treasures in Chinese cuisine. Fish maw is mainly produced from croaker, which is the most highly priced. However, some of the fish maw being sold as croaker maw are in fact not from croaker, but from the Nile perch Lates niloticus. The present work determined and compared the proximate composition, amino acid and fatty acid composition of croaker Protonibea diacanthus maw and perch L. niloticus maw. The results indicated that both maws were high protein sources and low in fat content. The dominant amino acids in both maws were glycine, proline, glutamic acid, alanine and arginine. These amino acids constituted 66.2% and 66.4% of the total amino acids in P. diacanthus and L. niloticus, respectively. The ratio of FAA: TAA(functional amino acids: total amino acids) in both maws were 0.69. This is a good explanation for why fish maws have been widely utilized as a traditional tonic and remedy in Asia. Except valine and histidine, all the essential amino acid contents in P. diacanthus were higher than in L. niloticus. Moreover, croaker P. diacanthus maw contained more AA and DHA than perch L. niloticus maw, showing a higher ratio of n-3 / n-6, which is more desirable.展开更多
The persistence of malachite green (MG), and its metabolite leucomalachite green (LMG), in fish tissues is still unclear, leading to many trade disputes. In this research, we established and evaluated an HPLC method t...The persistence of malachite green (MG), and its metabolite leucomalachite green (LMG), in fish tissues is still unclear, leading to many trade disputes. In this research, we established and evaluated an HPLC method that could detect MG and LMG simultaneously, and then investigated the persistence of these two toxins in the tissues of juvenile perch (Lateolabrax japonicus) post sub-chronic MG exposure at 1.0 mg/L. Exposure lasted for 2 h everyday and was repeated six times. The perch were then placed in MG-free seawater for 100 d to eliminate the toxins. Results show that MG accumulated in the tissues, including the gills, liver, muscle, blood and viscera, and then was metabolized rapidly to LMG. The concentrations of these two toxins increased significantly with the accumulation process. In general, the highest concentrations of MG and LMG in all tissue exceeded 1 000 μg/kg, except for MG in the muscle. The order of accumulation levels (highest to lowest) of MG was gill>blood>liver>viscera>muscle, while that of LMG was liver>blood>gill>viscera>muscle. High levels of MG or LMG could persist for several hours but decreased rapidly during the elimination process. The concentration of LMG was much higher than that of MG during the experiment, especially in the gill, liver and blood. Therefore, the three tissues play important roles in toxin accumulation, biotransformation, and elimination. Although the MG and LMG concentrations in muscle were much lower than in other tissues, the content still exceeded the European minimum required performance limit (MRPL), even after 2 400 h (100 d) of elimination. This demonstrates that it is extremely difficult to eliminate MG and LMG from tissues of perch, and therefore use of these toxins is of concern to public health.展开更多
Fish size and harvest density generally exhibit a negative relationship in pond culture, but the influence that pond substrate type can have on this relationship is not well understood. To evaluate the influence of po...Fish size and harvest density generally exhibit a negative relationship in pond culture, but the influence that pond substrate type can have on this relationship is not well understood. To evaluate the influence of pond substrate type on yellow perch (<i></span><i><span style="font-family:Verdana;">Perca flavescens</span></i><span style="font-family:Verdana;"></i></span><span style="font-family:Verdana;">), harvest density (number/hectare) was linearly regressed against individual fingerling size (grams) for lined (n = 48) and earthen (n = 40) substrate ponds that were treated similarly in terms of organic fertilizer use and the number of days in the pond over 12 culture seasons at Blue Dog Lake State Hatchery, South Dakota, USA. Harvest density explained 45 and 39% of the variation in yellow perch size in lined and earthen-substrate ponds (all <i></span><i><span style="font-family:Verdana;">P</span></i><span style="font-family:Verdana;"></i></span><span style="font-family:Verdana;"> < 0.01). Comparison of regression lines indicated that fingerling size decreased as harvest density increased at a similar rate in both pond types (slope comparison, <i></span><i><span style="font-family:Verdana;">P</span></i><span style="font-family:Verdana;"></i></span><span style="font-family:Verdana;"> = 0.62);however, fingerling size was significantly larger in lined ponds regardless of density that varied from near 0 to 700,000 per hectare (y-intercept comparison, <i></span><i><span style="font-family:Verdana;">P</span></i><span style="font-family:Verdana;"></i></span><span style="font-family:Verdana;"> < 0.01). At the same harvest density, lined ponds will tend to produce larger yellow perch fingerlings compared to earthen ponds when similar organic fertilizers are used.展开更多
New born hatchlings of Calotes versicolor were reared in terrarium having narrow or wide perches for a period of 4-month and their snout vent length（SVL）, tail, fore and hindlimb lengths were measured at monthly int...New born hatchlings of Calotes versicolor were reared in terrarium having narrow or wide perches for a period of 4-month and their snout vent length（SVL）, tail, fore and hindlimb lengths were measured at monthly intervals. Limb postures（closer to the body or spread away from the body） were also recorded. The sprint speed was recorded in two and four-month old lizards on a 1 m long race track providing 45° or 60° slope. In both the groups, SVL and tail lengths were comparable but the limb lengths and their growth rates were significantly greater in lizards of wider perch group. The lizards reared with narrow perches positioned their limbs closer to the body; while those reared on wider perches spread their limbs away from their body. Further, the latter exhibited significantly higher sprint speed regardless of the slope of the race track over those of narrow perch group. Sprint speeds of lizards in both groups were correlated with the limb sizes. The study showed that the lizards reared on narrow or wide perches exhibited divergent adaptive responses（phenotypic plasticity） by developing longer or shorter limbs and corresponding changes in their sprint speeds. These findings support the idea that availability of perch structure during early development evokes adaptive plasticity in the limb development and associated locomotory performance in arboreal lizards like C. versicolor.展开更多
Distillers dried grains with solubles (DDGS) in combination with soy protein concentrate (SPC) with and without an essential amino acid (EAA) complex were assessed as protein alternatives in juvenile Yellow Perch Perc...Distillers dried grains with solubles (DDGS) in combination with soy protein concentrate (SPC) with and without an essential amino acid (EAA) complex were assessed as protein alternatives in juvenile Yellow Perch Perca flavescens diets. Diets contained 5% FM, 40% SPC, and 20% or 40% DDGS each with or without EAA. No mortalities or health assessment differences were observed during the trial and all fish readily accepted the experimental diets. Diets supplemented with EAA produced greater weight gain, improved feed conversion, and apparent protein digestibility. Performance was consistently improved for fish fed diets containing amino acid supplements. Based on these results, Yellow Perch are able to utilize high levels of the plant proteins, accompanied with EAAs, as a FM replacer.展开更多
Considering the strong nonlinearity of Unmanned Aerial Vehicles(UAVs)resulting from high Angle of Attack(AOA)and fast maneuvering,we present a multi-model predictive control strategy for UAV maneuvering,which has a sm...Considering the strong nonlinearity of Unmanned Aerial Vehicles(UAVs)resulting from high Angle of Attack(AOA)and fast maneuvering,we present a multi-model predictive control strategy for UAV maneuvering,which has a small amount of online calculation.Firstly,we divide the maneuver envelope of UAV into several sub-regions on the basis of the gap metric theory.A novel algorithm is then developed to determine the ploytopic model for each sub-region.According to this,a Robust Model Predictive Control based on the Idea of Comprehensive optimization(ICE-RMPC)is proposed.The control law is designed offline and optimized online to reduce the computational expense.Then,the ICE-RMPC method is applied to design the controllers of sub-regions.In addition,to guarantee the stability of whole closed-loop system,a multi-model switching control strategy based on guardian maps is put forward.Finally,the tracking performance of proposed control strategy is demonstrated by an illustrative example.展开更多
In this study,a groundwater exploration survey was conducted using the DC Resistivity(DCR)method in a hydrogeological setting containing a perched aquifer.DCR data were gathered and an electrical tomography section wa...In this study,a groundwater exploration survey was conducted using the DC Resistivity(DCR)method in a hydrogeological setting containing a perched aquifer.DCR data were gathered and an electrical tomography section was recovered using conventional four-electrode instruments with a Schlumberger array and a two-dimensional(2D)inversion scheme.The proposed scheme was tested over a synthetic threedimensional(3D)subsurface model before deploying it in a field situation.The proposed method indicated that gathering data with simple four-electrode instruments at stations along a line and 2D inversion of datasets at multiple stations can recover depth intervals of the studied aquifer in the hydrogeological setting even if it has a 3D structure.In this study,2D inversion of parallel profiles formed a pseudo-3D volume of the subsurface resistivity structures and mapped out multiple resistive(>25 ohm·m)bodies at shallow(between 50-100 m)and deep sections(>150 m).In general,the proposed method is convenient to encounter geological units that have limited vertical and spatial extensions in any direction and presents resistivity contrast from groundwater-bearing geologic materials.展开更多
The northward drift of the Indian Plate and its collision with Eurasia have profoundly impacted the evolutionary history of the terrestrial organisms, especially the ones along the Indian Ocean rim. Climbing perches(A...The northward drift of the Indian Plate and its collision with Eurasia have profoundly impacted the evolutionary history of the terrestrial organisms, especially the ones along the Indian Ocean rim. Climbing perches(Anabantidae) are primary freshwater fishes showing a disjunct south Asian-African distribution,but with an elusive paleobiogeographic history due to the lack of fossil evidence. Here, based on an updated time-calibrated anabantiform phylogeny integrating a number of relevant fossils, the divergence between Asian and African climbing perches is estimated to have occurred in the middle Eocene(ca.40 Ma, Ma: million years ago), a time when India had already joined with Eurasia. The key fossil lineage is ?Eoanabas, the oldest anabantid known so far, from the upper Oligocene of the Tibetan Plateau.Ancestral range reconstructions suggest a Southeast Asian origin in the early Eocene(ca. 48 Ma) and subsequent dispersals to Tibet and then India for this group. Thereby we propose their westbound dispersal to Africa via the biotic bridge between India and Africa. If so, climbing perch precursors had probably followed the paleobiogeographical route of snakehead fishes, which have a slightly older divergence between African and Asian taxa. As such, our study echoes some recent molecular analyses in rejecting the previously held ‘‘Gondwana continental drift vicariance" or late Mesozoic dispersal scenarios for the climbing perches, but provides a unique biogeographical model to highlight the role of the preuplift Tibet and the docked India in shaping the disjunct distribution of some air-breathing freshwater fishes around the Indian Ocean.展开更多
The purpose of this study was to evaluate the potential of a host-associated Bacillus subtilis 1-C-7 as a probiotic for Chinese perch(Siniperca chuatsi).Four test diets were formulated to contain graded levels of B.su...The purpose of this study was to evaluate the potential of a host-associated Bacillus subtilis 1-C-7 as a probiotic for Chinese perch(Siniperca chuatsi).Four test diets were formulated to contain graded levels of B.subtilis 1-C-7 at 0(CY),0.85×10^(8)(Y1),0.95×10^(9)(Y2)and 0.91×10^(10)(Y3)CFU/kg diet.The test fish with initial weight 30.0±1.2 g were fed the 4 test diets with 3 replicates in an indoor water-flow aquaculture system with 12 net cages(40 fish/cage)for 10 wk.At the conclusion of the feeding trial,the probiotic effects of B.subtilis on Chinese perch were analyzed based on growth performance,serum biochemical indices,histologic morphology of liver and gut,gut microbiota and the resistance to Aero-monas hydrophila.The results showed that the percentage of weight gain had no significant change in the Y1 and Y2 groups(P>0.05)but decreased in the Y3 group compared to that in the CY group(P<0.05).The fish in the Y3 group displayed the highest activity of serum alanine aminotransferase(ALT)and aspartate aminotransferase(AST)among these 4 groups(P<0.05).The fish in the CY group had the highest value of malondialdehyde in the liver(P<0.05)and showed severe nuclear migration and vacuolization of hepatocytes.The morphology indicated that all test fish had poor intestinal health.However,the fish in the Y1 group had a relatively normal intestinal histologic structure.The mid gut microbial diversity analysis showed that dietary B.subtilis supplementation increased the abundance of probiotics such as Tenericutes and Bacteroides,whereas it reduced the abundance of pernicious bacteria such as Proteobacteria,Actinobacteria,Thermophilia and Spirochaetes.The challenge test showed that dietary B.subtilis supplementation increased the resistance to A.hydrophila in Chinese perch.In conclusion,dietary supplementation of 0.85×10^(8)CFU/kg B.subtilis 1-C-7 could improve the intestinal microbiota,intestinal health and disease resistance in Chinese perch,but more or excessive supple-mentation could reduce growth performance and have negative effects on health.展开更多
基金financially supported by National Key Research&Development Program of China[Grant No.2020YFB1313000]National Natural Science Foundation of China[Grant No.62003060]+1 种基金China Postdoctoral Science Foundation[2022M720566]Natural Science Foundation of Chongqing,China[CSTB2022NSCQ-MSX1297].
文摘Perching allows small Unmanned Aerial Vehicles(UAVs)to maintain their altitude while significantly extending their flight duration and reducing noise.However,current research on flying habitats is poorly adapted to unstructured environments,and lacks autonomous capabilities,requiring ideal experimental environments and remote control by personnel.To solve these problems,in this paper,we propose a bat-like UAV perching mechanism by investigating the bat upside-down perching method,which realizes double self-locking in the perching state using the ratchet and four-link dead point mechanisms.Based on this perching mechanism,this study proposes a control strategy for UAVs to track targets and accomplish flight perching autonomously by combining a binocular camera,single-point LiDAR,and pressure sensors.Autonomous perching experiments were conducted for crossbar-type objects outdoors.The experimental results show that a multirotor UAV equipped with the perching mechanism and sensors can reliably achieve autonomous flight perching and re-flying off the target outdoors.The power consumption is reduced to 2.9%of the hovering state when perched on the target object.
基金Project (No. Y97D02061) supported by the Natural Science Foundation of Shandong Province, China.
文摘The mineral stability and solute activities of soil solution extracted from selected horizons of seven studied pedons of Alfisols in Kentucky, USA, and the relationship between distribution of iron-manganese concretions and the restrictive layers were investigated. The results showed that the genesis and development of these soils and mineral weathering trends were strongly influenced by the depth of bedrock and the presence of perched water tables at lithic (limestone) interfaces due to the dissolution and buffering effect of limestone bedrock. The extractable Mg/Ca ratio as depth function and soil depth above bedrock could be used as indices of weathering and degree of soil development. Maximum iron-manganese concretion accumulation was found to occur in the horizon overlying clay horizon (>40% clay) with a sharp increase in clay content (>10%), which suggested that zones of Fe-Mn concretion accumulation in soils of the Inner Bluegrass Region appeared to be a sensitive genetic indicator of argillic horizons with restrictive permeability.
基金supported by the National Key R&D Program of China[Grant No.2020YFB1313000]National Natural Science Foundation of China[Grant No.51975070,62003060,62073211].
文摘Energy consumption and acoustic noise can be significantly reduced through perching in the sustained flights of small Unmanned Aerial Vehicles(UAVs).However,the existing flying perching robots lack good adaptability or loading capacity in unstructured environments.Aiming at solving these problems,a deformable UAV perching mechanism with strong adaptability and high loading capacity,which is inspired by the structure and movements of birds'feet,is presented in this paper.Three elastic toes,an inverted crank slider mechanism used to realize the opening and closing movements,and a gear mechanism used to deform between two configurations are included in this mechanism.With experiments on its performance towards different objects,Results show that it can perch on various objects reliably,and its payload is more than 15 times its weight.By integrating it with a quadcopter,it can perch on different types of targets in outdoor environments,such as tree branches,cables,eaves,and spherical lamps.In addition,the energy consumption of the UAV perching system when perching on objects can be reduced to 0.015 times that of hovering.
基金Project supported by the National Natural Science Foundation of China(Grant No.51705459)the China Postdoctoral Science Foundation.
文摘The key to high manoeuvre ability in bird flight lies in the combined morphing of wings and tail.The perching of a wild Haliaeetus Albicilla without running or wing flapping is recorded and investigated using a high-speed digital video.A shape reconstruction method is proposed to describe wing contours and tail contours during perching.The avian airfoil geometries of the Aquila Chrysaetos are extracted from noncontact surface measurements using a ROMBER 3D laser scanner.The wing planform,chord distribution and twist distribution are fitted in convenient analytical expressions to obtain a 3D wing geometry.A three-jointed arm model is proposed to associate with the 3D wing geometry,while a one-joint arm model is proposed to describe the kinematics of tail.Therefore,a 3D bird model is established.The perching sequences of the wild eagle are recaptured and regenerated with the proposed 3D bird model.A quasi-steady aerodynamic model is applied in the aerodynamic predictions,a four-step Adams-Bashforth method is used to calculate the ordinary differential equations,thus a BFGS based optimization method is established to predict the perching motions.
文摘The technology of homology cloning and anchored PCR was used to clone the IL-1β gene from the Japanese sea perch （Lateolabrax iaponicus）. The full-length cDNA of sea perch IL-1β was 1 310 bp, including a 5＇ untranslated regiop （UTR） of 136 bp, a 3＇ UTR ot 430 bp, and an ORF of 774 bp encoding a polypeptide of 258 amino acids with an estimated molecular mass of 29.31 kDa. The searches for nucleotides and protein sequence similarities with the BLAST analysis indicated that the deduced amino acid sequence of sea perch IL-1β was homological to the IL-1β in other fish species and even the mammalian. Conserved signature sequences of the IL-1β gene family were found in the sea perch IL-1β deduced amino acid sequence. Temporal expressions of the IL-1β gene in LPS or iridovirus challenged group and in control group were measured by the semi-quantitative RT-PCR. The mRNA transcripts of IL-1β could be detected in head-kidney, spleen, liver, gill and heart of the healthy individuals, and the expression level of IL-1β in head-kidney, spleen and gill was higher than that in liver and heart, but it was hard to be detected in the brain. After being stimulated by the LPS or iridovirus, the IL-1β expression in most of examined tissues was up-regulated, and also could be detected in the brain. These results indicated that the expression of sea perch IL-1β was constitutive and could be up-regulated by immune effector stimulation. Therefore the sea perch IL-1β could play a critical role in the host-pathogen interaction.
基金supported by the National Natural Science Foundation of China (No.31201999)the Natural Science Foundation of Guangdong Province, China (No.2014A030307022)+5 种基金the Special Support Program of Guangdong Province, China (No.2014TQ01N621)the Foundation for Distinguished Young Teachers in Higher Education of Guangdong, China (No.Yq2014115)the Foundation of Education Bureau of Guangdong Province (No.2014KTSCX159)the Technology Program of Guangdong Province (No.2015A030302089)the Overseas Scholarship Program for Elite Young and Middle-aged Teachers of Lingnan Normal University, the Technology Program of Zhanjiang (Nos.2015A03017, 2014A03011)the Guangxi Key Laboratory of Beibu Gulf Marine Biodiversity Conservation, Qinzhou University (No.2015KB04)
文摘Fish maw(the dried swimbladders of fish) is ranked in the list of the four sea treasures in Chinese cuisine. Fish maw is mainly produced from croaker, which is the most highly priced. However, some of the fish maw being sold as croaker maw are in fact not from croaker, but from the Nile perch Lates niloticus. The present work determined and compared the proximate composition, amino acid and fatty acid composition of croaker Protonibea diacanthus maw and perch L. niloticus maw. The results indicated that both maws were high protein sources and low in fat content. The dominant amino acids in both maws were glycine, proline, glutamic acid, alanine and arginine. These amino acids constituted 66.2% and 66.4% of the total amino acids in P. diacanthus and L. niloticus, respectively. The ratio of FAA: TAA(functional amino acids: total amino acids) in both maws were 0.69. This is a good explanation for why fish maws have been widely utilized as a traditional tonic and remedy in Asia. Except valine and histidine, all the essential amino acid contents in P. diacanthus were higher than in L. niloticus. Moreover, croaker P. diacanthus maw contained more AA and DHA than perch L. niloticus maw, showing a higher ratio of n-3 / n-6, which is more desirable.
基金Supported by the Special Fund of Chinese Government for Basic Scientific Research Operations in Commonweal Research Institute (Yellow Sea Fisheries Research Institute) (No. 2007-qn-12)the Strategic Research Grant of the Databases and Risk Analysis of POPs in Aquatic Products (No. 2005DIB4J049)the Standard System Research on Quality and Safety of Aquatic Products (No. 2004DEA70880)
文摘The persistence of malachite green (MG), and its metabolite leucomalachite green (LMG), in fish tissues is still unclear, leading to many trade disputes. In this research, we established and evaluated an HPLC method that could detect MG and LMG simultaneously, and then investigated the persistence of these two toxins in the tissues of juvenile perch (Lateolabrax japonicus) post sub-chronic MG exposure at 1.0 mg/L. Exposure lasted for 2 h everyday and was repeated six times. The perch were then placed in MG-free seawater for 100 d to eliminate the toxins. Results show that MG accumulated in the tissues, including the gills, liver, muscle, blood and viscera, and then was metabolized rapidly to LMG. The concentrations of these two toxins increased significantly with the accumulation process. In general, the highest concentrations of MG and LMG in all tissue exceeded 1 000 μg/kg, except for MG in the muscle. The order of accumulation levels (highest to lowest) of MG was gill>blood>liver>viscera>muscle, while that of LMG was liver>blood>gill>viscera>muscle. High levels of MG or LMG could persist for several hours but decreased rapidly during the elimination process. The concentration of LMG was much higher than that of MG during the experiment, especially in the gill, liver and blood. Therefore, the three tissues play important roles in toxin accumulation, biotransformation, and elimination. Although the MG and LMG concentrations in muscle were much lower than in other tissues, the content still exceeded the European minimum required performance limit (MRPL), even after 2 400 h (100 d) of elimination. This demonstrates that it is extremely difficult to eliminate MG and LMG from tissues of perch, and therefore use of these toxins is of concern to public health.
文摘Fish size and harvest density generally exhibit a negative relationship in pond culture, but the influence that pond substrate type can have on this relationship is not well understood. To evaluate the influence of pond substrate type on yellow perch (<i></span><i><span style="font-family:Verdana;">Perca flavescens</span></i><span style="font-family:Verdana;"></i></span><span style="font-family:Verdana;">), harvest density (number/hectare) was linearly regressed against individual fingerling size (grams) for lined (n = 48) and earthen (n = 40) substrate ponds that were treated similarly in terms of organic fertilizer use and the number of days in the pond over 12 culture seasons at Blue Dog Lake State Hatchery, South Dakota, USA. Harvest density explained 45 and 39% of the variation in yellow perch size in lined and earthen-substrate ponds (all <i></span><i><span style="font-family:Verdana;">P</span></i><span style="font-family:Verdana;"></i></span><span style="font-family:Verdana;"> < 0.01). Comparison of regression lines indicated that fingerling size decreased as harvest density increased at a similar rate in both pond types (slope comparison, <i></span><i><span style="font-family:Verdana;">P</span></i><span style="font-family:Verdana;"></i></span><span style="font-family:Verdana;"> = 0.62);however, fingerling size was significantly larger in lined ponds regardless of density that varied from near 0 to 700,000 per hectare (y-intercept comparison, <i></span><i><span style="font-family:Verdana;">P</span></i><span style="font-family:Verdana;"></i></span><span style="font-family:Verdana;"> < 0.01). At the same harvest density, lined ponds will tend to produce larger yellow perch fingerlings compared to earthen ponds when similar organic fertilizers are used.
文摘New born hatchlings of Calotes versicolor were reared in terrarium having narrow or wide perches for a period of 4-month and their snout vent length（SVL）, tail, fore and hindlimb lengths were measured at monthly intervals. Limb postures（closer to the body or spread away from the body） were also recorded. The sprint speed was recorded in two and four-month old lizards on a 1 m long race track providing 45° or 60° slope. In both the groups, SVL and tail lengths were comparable but the limb lengths and their growth rates were significantly greater in lizards of wider perch group. The lizards reared with narrow perches positioned their limbs closer to the body; while those reared on wider perches spread their limbs away from their body. Further, the latter exhibited significantly higher sprint speed regardless of the slope of the race track over those of narrow perch group. Sprint speeds of lizards in both groups were correlated with the limb sizes. The study showed that the lizards reared on narrow or wide perches exhibited divergent adaptive responses（phenotypic plasticity） by developing longer or shorter limbs and corresponding changes in their sprint speeds. These findings support the idea that availability of perch structure during early development evokes adaptive plasticity in the limb development and associated locomotory performance in arboreal lizards like C. versicolor.
文摘Distillers dried grains with solubles (DDGS) in combination with soy protein concentrate (SPC) with and without an essential amino acid (EAA) complex were assessed as protein alternatives in juvenile Yellow Perch Perca flavescens diets. Diets contained 5% FM, 40% SPC, and 20% or 40% DDGS each with or without EAA. No mortalities or health assessment differences were observed during the trial and all fish readily accepted the experimental diets. Diets supplemented with EAA produced greater weight gain, improved feed conversion, and apparent protein digestibility. Performance was consistently improved for fish fed diets containing amino acid supplements. Based on these results, Yellow Perch are able to utilize high levels of the plant proteins, accompanied with EAAs, as a FM replacer.
基金co-supported by the National Natural Science Foundation of China(Nos.61873126,11572149)。
文摘Considering the strong nonlinearity of Unmanned Aerial Vehicles(UAVs)resulting from high Angle of Attack(AOA)and fast maneuvering,we present a multi-model predictive control strategy for UAV maneuvering,which has a small amount of online calculation.Firstly,we divide the maneuver envelope of UAV into several sub-regions on the basis of the gap metric theory.A novel algorithm is then developed to determine the ploytopic model for each sub-region.According to this,a Robust Model Predictive Control based on the Idea of Comprehensive optimization(ICE-RMPC)is proposed.The control law is designed offline and optimized online to reduce the computational expense.Then,the ICE-RMPC method is applied to design the controllers of sub-regions.In addition,to guarantee the stability of whole closed-loop system,a multi-model switching control strategy based on guardian maps is put forward.Finally,the tracking performance of proposed control strategy is demonstrated by an illustrative example.
文摘In this study,a groundwater exploration survey was conducted using the DC Resistivity(DCR)method in a hydrogeological setting containing a perched aquifer.DCR data were gathered and an electrical tomography section was recovered using conventional four-electrode instruments with a Schlumberger array and a two-dimensional(2D)inversion scheme.The proposed scheme was tested over a synthetic threedimensional(3D)subsurface model before deploying it in a field situation.The proposed method indicated that gathering data with simple four-electrode instruments at stations along a line and 2D inversion of datasets at multiple stations can recover depth intervals of the studied aquifer in the hydrogeological setting even if it has a 3D structure.In this study,2D inversion of parallel profiles formed a pseudo-3D volume of the subsurface resistivity structures and mapped out multiple resistive(>25 ohm·m)bodies at shallow(between 50-100 m)and deep sections(>150 m).In general,the proposed method is convenient to encounter geological units that have limited vertical and spatial extensions in any direction and presents resistivity contrast from groundwater-bearing geologic materials.
基金supported by the Strategic Priority Research Program of the Chinese Academy of Sciences (CAS) (XDA20070203, XDB26000000, XDB310403, XDA20070301)the Second Tibetan Plateau Scientific Expedition Program, the National Natural Science Foundation of China (41872006)Youth Innovation Promotion Association, CAS (2017103, 2017439)
文摘The northward drift of the Indian Plate and its collision with Eurasia have profoundly impacted the evolutionary history of the terrestrial organisms, especially the ones along the Indian Ocean rim. Climbing perches(Anabantidae) are primary freshwater fishes showing a disjunct south Asian-African distribution,but with an elusive paleobiogeographic history due to the lack of fossil evidence. Here, based on an updated time-calibrated anabantiform phylogeny integrating a number of relevant fossils, the divergence between Asian and African climbing perches is estimated to have occurred in the middle Eocene(ca.40 Ma, Ma: million years ago), a time when India had already joined with Eurasia. The key fossil lineage is ?Eoanabas, the oldest anabantid known so far, from the upper Oligocene of the Tibetan Plateau.Ancestral range reconstructions suggest a Southeast Asian origin in the early Eocene(ca. 48 Ma) and subsequent dispersals to Tibet and then India for this group. Thereby we propose their westbound dispersal to Africa via the biotic bridge between India and Africa. If so, climbing perch precursors had probably followed the paleobiogeographical route of snakehead fishes, which have a slightly older divergence between African and Asian taxa. As such, our study echoes some recent molecular analyses in rejecting the previously held ‘‘Gondwana continental drift vicariance" or late Mesozoic dispersal scenarios for the climbing perches, but provides a unique biogeographical model to highlight the role of the preuplift Tibet and the docked India in shaping the disjunct distribution of some air-breathing freshwater fishes around the Indian Ocean.
基金supported by the Fund of Fujian Key Laboratory of Functional Aquafeed and Culture Environment Control(FACE20200004)and China Agriculture Research System(CARS-46).
文摘The purpose of this study was to evaluate the potential of a host-associated Bacillus subtilis 1-C-7 as a probiotic for Chinese perch(Siniperca chuatsi).Four test diets were formulated to contain graded levels of B.subtilis 1-C-7 at 0(CY),0.85×10^(8)(Y1),0.95×10^(9)(Y2)and 0.91×10^(10)(Y3)CFU/kg diet.The test fish with initial weight 30.0±1.2 g were fed the 4 test diets with 3 replicates in an indoor water-flow aquaculture system with 12 net cages(40 fish/cage)for 10 wk.At the conclusion of the feeding trial,the probiotic effects of B.subtilis on Chinese perch were analyzed based on growth performance,serum biochemical indices,histologic morphology of liver and gut,gut microbiota and the resistance to Aero-monas hydrophila.The results showed that the percentage of weight gain had no significant change in the Y1 and Y2 groups(P>0.05)but decreased in the Y3 group compared to that in the CY group(P<0.05).The fish in the Y3 group displayed the highest activity of serum alanine aminotransferase(ALT)and aspartate aminotransferase(AST)among these 4 groups(P<0.05).The fish in the CY group had the highest value of malondialdehyde in the liver(P<0.05)and showed severe nuclear migration and vacuolization of hepatocytes.The morphology indicated that all test fish had poor intestinal health.However,the fish in the Y1 group had a relatively normal intestinal histologic structure.The mid gut microbial diversity analysis showed that dietary B.subtilis supplementation increased the abundance of probiotics such as Tenericutes and Bacteroides,whereas it reduced the abundance of pernicious bacteria such as Proteobacteria,Actinobacteria,Thermophilia and Spirochaetes.The challenge test showed that dietary B.subtilis supplementation increased the resistance to A.hydrophila in Chinese perch.In conclusion,dietary supplementation of 0.85×10^(8)CFU/kg B.subtilis 1-C-7 could improve the intestinal microbiota,intestinal health and disease resistance in Chinese perch,but more or excessive supple-mentation could reduce growth performance and have negative effects on health.
