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Early onset of a microcystin-producing cyanobacterial bloom in an agriculturally-influenced Great Lakes tributary

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Journal of Oceanology and Limnology 2018年第4期36卷 1112-1125页

作者： Robert Michael L.McKAY Taylor TUTTLE Laura A.REITZ George S.BULLERJAHN william R.CODY Adam J.McDOWELL Timothy W.davis Department of Biological Sciences Bowling Green State University Bowling Green OH 43403 USA Aquatic Taxonomy Specialists Malinta OH 43535 USA City of Defiance Water Division Defiance OH 43512 USA NOAA Great Lakes Environmental Research Laboratory Ann Arbor MI USA

In late May 2016, a cyanobacterial harmful algal bloom(cHAB) was detected in the Maumee River, the largest tributary to Lake Erie, the southernmost lake of the Laurentian Great Lakes system. Testing on 31 May identified Planktothrix agardhii as the dominant cyanobacterium with cell abundance exceeding 1.7×10~9 cells/L and total microcystins(MC) reaching 19 μg/L MC-LR equivalents, a level over 10-fold higher than the 2015 revised U.S. Environmental Protection Agency(EPA) national health advisory levels for drinking water exposure to adults. Low river discharge coincident with negligible precipitation through the latter half of May coincided with an 80% decline in river turbidity that likely favored bloom formation by a low-light adapted P. agardhii population. Also contributing to the c HAB were high initial nutrient loads and an increase of the river temperature from 13℃ to 26℃ over this same period. The bloom persisted through 5 June with microcystins exceeding 22 μg/L MC-LR equivalents at the bloom peak. By 6 June, the river had returned to its muddy character following a rain event and sampling on 7 June detected only low levels of toxin(<0.6 μg/L) at public water systems located near the bloom origin. The elevated toxin production associated with this early onset bloom was without precedent for the Maumee River and an unique attribute of the c HAB was the high proportion of potentially-toxic genotypes. Whereas Planktothrix spp. is common in lotic environments, and has been previously detected in the Maumee, blooms are not commonly reported. This early onset, microcystin-producing c HAB provided a rare opportunity to glean insights into environmental factors that promote bloom development and dominance by Planktothrix in lotic environments.

关键词： cyanobacteria microcystin Planktothrix qPCR river

Physical and chemical processes promoting dominance of the toxic cyanobacterium Cylindrospermopsis raciborskii

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Chinese Journal of Oceanology and Limnology 2011年第4期29卷 883-891页

作者： Michele A. BURFORD Timothy W. davis Australian Rivers Institute Griffith University Nathan Qld. 4111 Australia

The freshwater cyanobacterium, Cylindrospermopsis raciborskii （Woloszyflska） Seenayya and Subba Raju is a common species in lakes and reservoirs globally. In some areas of the world it can produce cytoand hepatotoxins （cylindrospermopsins, saxitoxins）, making blooms of this species a serious health concern for humans. In the last 10 15 years, there has been a considerable body of research conducted on the ecology, physiology and toxin production of this species and this paper reviews these studies with a focus on the cylindrospermopsin （CYN）-producing strains. C. raciborskii has low light requirements, close to neutral buoyancy, and a wide temperature tolerance, giving it the capacity to grow in many lentic waterbodies. It also has a flexible strategy with respect to nitrogen （N） utilisation; being able to switch between utilising fixed and atmospheric N as sources of N fluctuate. Additionally this species has a high phosphate （DIP） affinity and storage capacity. Like many cyanobacteria, it also has the capacity to use dissolved organic phosphorus （DOP）. Changes in nutrient concentrations, light levels and temperature have also been found to affect production of the toxin CYN by this species. However, optimal toxin production does not necessarily occur when growth rates are optimal. Additionally, different strains of C. raciborskii vary in their cell quota of CYN, making it difficult to predict toxin concentrations, based on C. raciborskii cell densities. In summary, the ecological flexibility of this organism means that controlling blooms of C. raciborskii is a difficult undertaking. However, improved understanding of factors promoting the species and toxin production by genetically capable strains will lead to improved predictive models of blooms.

关键词： cyanobacteria freshwater algal toxins nutrients light temperature

Supersonic Transport Redux？

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Engineering 2017年第6期3卷 785-786页

作者： Lance A. davis Senior Advisor US National Academy of Engineering

On June 26, 2017, the US National Aeronautics and Space Administration （NASA） announced that it had completed a preliminary design review （PDR） for its Quiet Supersonic Transport （QueSST）, designed with the pros... 详细信息

关键词： CCS 可再生能源发电

Pelage color of red bats Lasiurus borealis varies with body size:An image analysis of museum specimens

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Current Zoology 2010年第4期56卷 401-405页

作者： Andrew K.davis Steven B.CASTLEBERRY D.B. Warnell School of Forestry and Natural Resources The University of Georgia

Mammalian pelage color can vary among individuals of many species, although this intraspecific variation is oftenoverlooked by researchers, perhaps because of its sometimes subtle nature and difficulty in assessing it quantitatively. Thus, suchvariation is rarely studied in mammals, and this is especially true within the order Chiroptera, where there has been very little empiricalresearch. We examined museum specimens of red bats (Lasiurus borealis, family Vespertilionidae) from Georgia, USA, todetermine the extent of sexual dimorphism in pelage color and to explore possible associations between body size and pelagecolor. We photographed 54 specimens under uniform lighting, and used an image analysis program to measure pelage hue on theuropatagium region, which is fully furred in members of the genus Lasiurus. Statistical analyses of pelage hue scores showedmales had significantly redder pelage than females when considered alone, but when examined together with effects of body sizeand collection year, sex was not significant, and collection year and body size were. More recent specimens tended to be less redthan older specimens, which might indicate a wearing of the buffy tips of hairs from older specimens, and smaller bats of bothsexes tended to be more red. These interesting findings are encouraging and we suggest that future explorations into intraspecificvariation in pelage color of bats using this or similar approaches are warranted to clarify the significance of the patterns. Thisstudy also demonstrated that care must be taken in analyses of mammalian pelage color from older museum skins, or at least thatresearchers must take into account the age of the specimens .

关键词： Pelage color Sexual dimorphism Red bats Lasiurus borealis Image analysis

The Shale Oil and Gas Revolution

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Engineering 2018年第4期4卷 438-439页

作者： Lance A. davis Senior Advisor US National Academy of Engineering USA

The global energy landscape has very often been subject to upheaval due to geopolitical strife. Americans old enough will vividly recall waiting in long lines at gasoline stations during the 1973 oil embargo. At present, there is another sort of upheaval afoot that is totally driven by technology-hydraulic fracturing and horizontal drilling.

关键词：水平钻井技术水力压裂石油化工行业技术创新

An evaluation of a catch and release trout regulation in Rapid Creek,South Dakota

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Aquaculture and Fisheries 2023年第5期8卷 558-563页

作者： Jacob L.davis South Dakota Department of Game Fish and Parks4130 Adventure TrailRapid CitySD57702USA

Often,catch and release regulations are meant to maximize a fisheries potential to create trophy fish.I evaluated adult Brown Trout populations at five locations within Rapid Creek within Rapid City,SD over a two-year *** each year,one of these locations was within a catch and release area,while two were *** 2012,density and biomass estimates were higher in a site located outside of the catch and release ***,size structure within the catch and release area was only significantly larger than one of the two sites outside of the regulation *** relative weight values were inversely related to density estimates,with the lowest density sites having the highest mean relative ***,a site outside of the catch and release area had the highest abundance and biomass estimates in *** cumulative length distribution was significantly different between the site within the catch and release area and the two located *** weight was significantly higher in the catch and release area than the two sites *** population characteristics within the catch and release area were not consistently better than outside,it is more likely that factors such as habitat and density dependence are impacting the Brown Trout population more than the regulation itself.

关键词： Trout Regulations Catch and release

Variability of waste copper slag concrete and its effect on the seismic safety of reinforced concrete building: A case study

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Frontiers of Structural and Civil Engineering 2022年第1期16卷 117-130页

作者： Swetapadma PANDA Nikhil P.ZADE Pradip SARKAR Robin davis Department of Civil Engineering Institute of Technical Education and ResearchOdisha 751030India Department of Civil Engineering National Institute of Technology RourkelaOdisha 769008India Department of Civil Engineering National Institute of Technology CalicutKerala 673601India

Proven research output on the behavior of structures made of waste copper slag concrete can improve its utilization in the construction industry and thereby help to develop a sustainable built *** numerous studies on waste copper slag concrete can be found in the published literature,no research has focused on the structural application of this type of *** particular,the variability in the strength properties of waste copper slag concrete,which is required for various structural applications,such as limit state design formulation,reliability-based structural analysis,etc.,has so far not attracted the attention of *** paper quantifies the uncertainty associated with the compressive-,flexural-and split tensile strength of hardened concrete with different dosages of waste copper slag as fine ***-fit probability distribution models are proposed based on statistical analyses of strength data generated from laboratory *** addition,the paper presents a reliability-based seismic risk assessment of a typical waste copper slag incorporated reinforced concrete framed building,considering the proposed distribution *** results show that waste copper slag can be safely used for seismic resistant structures as it results in an identical probability of failure and dispersion in the drift demand when compared with a conventional concrete building made of natural sand.

关键词： waste copper slag quantification of variability goodness-of-fit test seismic risk assessment PSDM

Spon's Landscape and External Works Price Book 2005: Free CDROM (Spons Price Books) 24

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Parallelization of an Implicit Algorithm for Multi-Dimensional Particle-in-Cell Simulations

2004年

作者： davis Langdon

来源：畅想之星图书光盘版（南... 评论

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Communications in Computational Physics 2014年第8期16卷 599-611页

作者： George M.Petrov Jack davis Naval Research Laboratory Plasma Physics Division4555 Overlook Ave.SWWashingtonDC 20375USA.

The implicit 2D3V particle-in-cell(PIC)code developed to study the interaction of ultrashort pulse lasers with matter[*** and ***,Computer ***.179,868(2008);*** 18,073102(2011)]has been parallelized using MPI(Message Passing Interface).The parallelization strategy is optimized for a small number of computer cores,up to about *** on the algorithm implementation are given with emphasis on code optimization by overlapping computations with *** evaluation for 1D domain decomposition has been made on a small Linux cluster with 64 computer cores for two typical regimes of PIC operation:”particle dominated”,for which the bulk of the computation time is spent on pushing particles,and”field dominated”,for which computing the fields is *** a small number of computer cores,less than 32,the MPI implementation offers a significant numerical *** the”particle dominated”regime it is close to the maximum theoretical one,while in the”field dominated”regime it is about 75-80%of the maximum *** a number of cores exceeding 32,performance degradation takes place as a result of the adopted 1D domain *** code parallelization will allow future implementation of atomic physics and extension to three dimensions.

关键词： Particle-in-cell Maxwell equations MPI lasertarget interaction.