1,877 research outputs found
A niche model to predict Microcystis bloom decline in Chaohu Lake, China
Cyanobacterial blooms occur frequently in lakes due to eutrophication. Although a number of models have been proposed to forecast algal blooms, a good and applicable method is still lacking. This study explored a simple and effective mathematical-ecological model to evaluate the growth status and predict the population dynamics of Microcystis blooms. In this study, phytoplankton were collected and identified from 8 sampling sites in Chaohu Lake every month from July to October, 2010. The niche breadth and niche overlap of common species were calculated using standard equations, and the potential relative growth rates of Microcystis were calculated as a weighted-value of niche overlap. In July, the potential relative growth rate was 2.79 (a.u., arbitrary units) but then rapidly declined in the following months to -3.99 a.u. in September. A significant correlation (R =0.998, P < 0.01) was found in the model between the net-increase in biomass of Microcystis in the field and the predicted values calculated by the niche model, we concluded that the niche model is suitable for forecasting the dynamics of Microcystis blooms. Redundancy analysis indicated that decreases in water temperature, dissolved oxygen and total dissolved phosphorus might be major factors underlying bloom decline. Based on the theory of community succession being caused by resource competition, the growth and decline of blooms can be predicted from a community structure. This may provide a basis for early warning and control of algal blooms.Cyanobacterial blooms occur frequently in lakes due to eutrophication. Although a number of models have been proposed to forecast algal blooms, a good and applicable method is still lacking. This study explored a simple and effective mathematical-ecological model to evaluate the growth status and predict the population dynamics of Microcystis blooms. In this study, phytoplankton were collected and identified from 8 sampling sites in Chaohu Lake every month from July to October, 2010. The niche breadth and niche overlap of common species were calculated using standard equations, and the potential relative growth rates of Microcystis were calculated as a weighted-value of niche overlap. In July, the potential relative growth rate was 2.79 (a.u., arbitrary units) but then rapidly declined in the following months to -3.99 a.u. in September. A significant correlation (R =0.998, P < 0.01) was found in the model between the net-increase in biomass of Microcystis in the field and the predicted values calculated by the niche model, we concluded that the niche model is suitable for forecasting the dynamics of Microcystis blooms. Redundancy analysis indicated that decreases in water temperature, dissolved oxygen and total dissolved phosphorus might be major factors underlying bloom decline. Based on the theory of community succession being caused by resource competition, the growth and decline of blooms can be predicted from a community structure. This may provide a basis for early warning and control of algal blooms
Perceptual Grouping without Awareness: Superiority of Kanizsa Triangle in Breaking Interocular Suppression
Much information could be processed unconsciously. However, there is no direct evidence on whether perceptual grouping could occur without awareness. To answer this question, we investigated whether a Kanizsa triangle (an example of perceptual grouping) is processed differently from stimuli with the same local components but are ungrouped or weakly grouped. Specifically, using a suppression time paradigm we tested whether a Kanizsa triangle would emerge from interocular continuous flash suppression sooner than control stimuli. Results show a significant advantage of the Kanizsa triangle: the Kanizsa triangle emerged from suppression noise significantly faster than the control stimulus with the local Pacmen randomly rotated (t(9)β=ββ2.78, pβ=β0.02); and also faster than the control stimulus with all Pacmen rotated 180Β° (t(11)β=ββ3.20, p<0.01). Additional results demonstrated that the advantage of the grouped Kanizsa triangle could not be accounted for by the faster detection speed at the conscious level for the Kanizsa figures on a dynamic noise background. Our results indicate that certain properties supporting perceptual grouping could be processed in the absence of awareness
The complete mitochondrial genome of Leiocassis crassilabris (Teleostei, Siluriformes: Bagridae)
The Leiocassis crassilabris is an important economic fish in China, and is widely distributed in south China, e.g. Yangtze River, Pearl River, and Min River, so it is a good model to study population genetics and geological changes of these regions. In this study, the complete mitochondrial genome sequence of L. crassilabris has been obtained with PCR. The gene arrangement and composition L. crassilabris of mitochondrial genome sequence are similar to most of the other vertebrates', which contains 13 protein-coding genes, 22 tRNA genes, 2 rRNA genes and a non-coding control region with the total length of 16,530 bp. Except for eight tRNA and ND6 genes, other genes are encoded on heavy-strand (H-strand). Similar to most other vertebrates, the bias of G and C have universality in different region (genes). The complete mitochondrial genome sequence of L. crassilabris would contribute to better understand population genetics, conservation, biogeography, evolution of this lineage.The Leiocassis crassilabris is an important economic fish in China, and is widely distributed in south China, e.g. Yangtze River, Pearl River, and Min River, so it is a good model to study population genetics and geological changes of these regions. In this study, the complete mitochondrial genome sequence of L. crassilabris has been obtained with PCR. The gene arrangement and composition L. crassilabris of mitochondrial genome sequence are similar to most of the other vertebrates', which contains 13 protein-coding genes, 22 tRNA genes, 2 rRNA genes and a non-coding control region with the total length of 16,530 bp. Except for eight tRNA and ND6 genes, other genes are encoded on heavy-strand (H-strand). Similar to most other vertebrates, the bias of G and C have universality in different region (genes). The complete mitochondrial genome sequence of L. crassilabris would contribute to better understand population genetics, conservation, biogeography, evolution of this lineage
Thiol-Functionalized Mesoporous Silica for Effective Trap of Mercury in Rats
The chance of exposure to heavy metal for human being rises severely today due to the increasing water contamination and air pollution. Here, we prepared a series of thiol-functionalized mesoporous silica as oral formulation for the prevention and treatment of heavy metal poisoning. The successful incorporation of thiol was verified by the FTIR spectra. SBA15-SH-10 was used for the study as it is of uniform mesopores and fine water dispersibility. In simulated gastrointestinal fluid, the thiol-functionalized mesoporous silica can selectively capture heavy metal, showing a very high affinity for inorganic mercury (II). The blood and urine mercury levels of rats fed with a diet containing Hg (II) and material were significantly lower than those of rats fed with the metal-rich diet only. On the contrary, the mercury content in fecal excretion of the treatment group increased more than twice as much as that of the control group. This result indicated that SBA15-SH-10 could effectively remove mercury (II) in vivo and the mercury loaded on SBA15-SH-10 would be excreted out. Hence, SBA15-SH-10 has potential application in preventing and treating heavy metal poisoning via digestive system
Isolation of Robinsoniella peoriensis from the fecal material of the endangered Yangtze finless porpoise, Neophocaena asiaeorientalis asiaeorientalis
The aim of this study was to determine the causative agent of diarrhea in an endangered Yangtze finless porpoise (Neophocaena asiaeorientalis asiaeorientalis). From the fecal material collected from this porpoise Robinsoniella peoriensis was isolated. (C) 2013 Elsevier Ltd. All rights reserved.The aim of this study was to determine the causative agent of diarrhea in an endangered Yangtze finless porpoise (Neophocaena asiaeorientalis asiaeorientalis). From the fecal material collected from this porpoise Robinsoniella peoriensis was isolated. (C) 2013 Elsevier Ltd. All rights reserved
Effects of Mach number on turbulent separation behaviours induced by blunt fin
An experimental study of the interaction between shock wave and turbulent boundary layer induced by blunt fin has been carried out at M-infinity = 7.8 using oil flow visualization and simultaneous measurements of fluctuating wall pressure and heat transfer. This paper presents the effects of Mach number on turbulent separation behaviours induced by blunt fin
Molecular cloning and characterization of interferon regulatory factor 1 (IRF-1), IRF-2 and IRF-5 in the chondrostean paddlefish Polyodon spathula and their phylogenetic importance in the Osteichthyes
The interferon regulatory factor (IRF) with its 10 members is a very important gene family related to innate immunity. Currently, most fish IRFs reported are from bony fish (teleosts). Cloning and sequencing of IRFs from chondrosteans, the so-called "ancient fish" including sturgeon, paddlefish, bichir and gar, are absent from the literature. In this study, three IRF genes PsIRF-1, PsIRF-2 and PsIRF-5, were cloned and characterized from the paddlefish (Polyodon spathula). PsIRF-1 includes an open reading frame (ORF) of 972 bp that encodes a putative protein of 324 amino acids; PsIRF-2 includes an ORF of 1023 bp encoding 341 amino acids and P5IRF-5 includes an ORF of 1491 bp that encodes 497 amino acids. The P5IRF-5 gene structure is similar to those in mammals but differs from those in teleosts in the first and second exons. Phylogenetic studies of the putative amino acid sequences of PsIRF-1, PsIRF-2 and PsIRF-5 based on the neighbor-joining and Bayesian inference method for Osteichthyes found widely accepted inter-relationships among actinopterygians and tetrapods. Reverse Transcription Polymerase Chain Reaction (RT-PCR) analysis of PsIRF-1, PsIRF-2 and P5IRF-5 in different paddlefish tissues shows higher levels of expression in gill, spleen and head kidney. Poly (I: C) (polyinosinic-polycytidylic acid) stimulation in vivo up-regulated PsIRF-1 and PsIRF-2 expression, while P5IRF-5 gene expression did not respond to the challenge of Poly (I: C). (C) 2011 Elsevier Ltd. All rights reserved.The interferon regulatory factor (IRF) with its 10 members is a very important gene family related to innate immunity. Currently, most fish IRFs reported are from bony fish (teleosts). Cloning and sequencing of IRFs from chondrosteans, the so-called "ancient fish" including sturgeon, paddlefish, bichir and gar, are absent from the literature. In this study, three IRF genes PsIRF-1, PsIRF-2 and PsIRF-5, were cloned and characterized from the paddlefish (Polyodon spathula). PsIRF-1 includes an open reading frame (ORF) of 972 bp that encodes a putative protein of 324 amino acids; PsIRF-2 includes an ORF of 1023 bp encoding 341 amino acids and P5IRF-5 includes an ORF of 1491 bp that encodes 497 amino acids. The P5IRF-5 gene structure is similar to those in mammals but differs from those in teleosts in the first and second exons. Phylogenetic studies of the putative amino acid sequences of PsIRF-1, PsIRF-2 and PsIRF-5 based on the neighbor-joining and Bayesian inference method for Osteichthyes found widely accepted inter-relationships among actinopterygians and tetrapods. Reverse Transcription Polymerase Chain Reaction (RT-PCR) analysis of PsIRF-1, PsIRF-2 and P5IRF-5 in different paddlefish tissues shows higher levels of expression in gill, spleen and head kidney. Poly (I: C) (polyinosinic-polycytidylic acid) stimulation in vivo up-regulated PsIRF-1 and PsIRF-2 expression, while P5IRF-5 gene expression did not respond to the challenge of Poly (I: C). (C) 2011 Elsevier Ltd. All rights reserved
Thermogravimetric and kinetic analysis of energy crop Jerusalem artichoke using the distributed activation energy model
Jerusalem artichoke has great potential as future feedstock for bioenergy production because of its high tuber yield (up to 90 t ha(-1)), appropriate biomass characteristics, low input demand, and positive environmental impact. The pyrolytic and kinetic characteristics of Jerusalem artichoke tubers were analyzed at heating rates of 5, 10, 20 and 30 A degrees C min(-1). TG and DTG curves in an inert (nitrogen) atmosphere suggested that there were three distinct stages of mass loss and the major loss occurs between about 190-380 A degrees C. Heating rate brought a lateral shift toward right in the temperature. And, it not only affects the temperature at which the highest mass loss rate reached, but also affect the maximum rate of mass loss. The distributed activation energy model (DAEM) was used to study the pyrolysis kinetics and provided reasonable fits to the experimental data. The activation energy (E) of tubers ranged from 146.40 to 232.45 kJ mol(-1), and the frequency factor (A) changed greatly corresponding to E values at different mass conversion.Jerusalem artichoke has great potential as future feedstock for bioenergy production because of its high tuber yield (up to 90 t ha(-1)), appropriate biomass characteristics, low input demand, and positive environmental impact. The pyrolytic and kinetic characteristics of Jerusalem artichoke tubers were analyzed at heating rates of 5, 10, 20 and 30 A degrees C min(-1). TG and DTG curves in an inert (nitrogen) atmosphere suggested that there were three distinct stages of mass loss and the major loss occurs between about 190-380 A degrees C. Heating rate brought a lateral shift toward right in the temperature. And, it not only affects the temperature at which the highest mass loss rate reached, but also affect the maximum rate of mass loss. The distributed activation energy model (DAEM) was used to study the pyrolysis kinetics and provided reasonable fits to the experimental data. The activation energy (E) of tubers ranged from 146.40 to 232.45 kJ mol(-1), and the frequency factor (A) changed greatly corresponding to E values at different mass conversion
Computational model of 18650 lithium-ion battery with coupled strain rate and SOC dependencies
Highly nonlinear structures and constituent materials and hazardous experiment situations have resulted in a pressing need for a numerical mechanical model for lithium-ion battery (LIB). However, such a model is still not well established. In this paper, an anisotropic homogeneous model describing the jellyroll and the battery shell is established and validated through compression, indentation, and bending tests at quasi-static loadings. In this model, state-of-charge (SOC) dependency of the LIB is further included through an analogy with the strain-rate effect. Moreover, with consideration of the inertia and strain rate effects, the anisotropic homogeneous model is extended into the dynamic regime and proven capable of predicting the dynamic response of the LIB using the drop-weight test. The established model may help to predict extreme cases with high SOCs and crashing speeds with an over 135% improved accuracy compared to traditional models. The established coupled strain rate and SOC dependencies of the numerical mechanical model for the LIB aims to provide a solid step toward unraveling and quantifying the complicated problems for research on LIB mechanical integrity. (C) 2016 Elsevier Ltd. All rights reserved
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