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Effects of Broussonetia papyrifera invasion and land use on vegetation characteristics in a tropical forest of Ghana

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Journal of Forestry Research 2019年第4期30卷 1363-1373页

作者： david M.Adigbli Alexander k.Anning James k.Adomak. Benedicta Y.Fosu-Mensah Institute for Environment and Sanitation Studies University of GhanaLegonAccraGhana Department of Theoretical and Applied Biology Kwame Nkrumah University of Science and TechnologyKumasiGhana Department of Botany University of GhanaLegonAccraGhana

The purpose of this study was to evaluate the effects of Broussonetia papyrifera(paper mulberry)invasion and land use on the floristic composition of a dry semideciduous forest in ***-five plots(25 m×25 m each),distributed among three land uses-selectively logged(SL);abandoned farmlands(AF);and an undisturbed reference(RF)-were *** showed lower tree species richness(S),diversity(H’),evenness(S)and basal area(BA)in the SL(46,0.78,0.32 and 269.12 m2 ha-1,respectively)and AF(40,0.53,0.45,and 131.16 m^2 ha^-1)sites compared to the RF site(79,2.66,0.87,963.72 m^2 ha^-1).Similar patterns were found at the shrub layer,but no differences were observed at the herb ***-metric multidimensional scaling ordination revealed distinct species composition among the land *** two disturbed habitats,SL and AF,were associated with increased *** invasion particularly in the overstory,with importance value index and mean relative density of 45 and 65.03%,and 42 and 53.29%,***,the species was only sparsely represented in the RF *** density of *** correlated negatively with H’,S,E,BA,and native tree density and *** findings highlight the strong link.between human land use(i.e.,logging and slash-andburn farming),invasion,and vegetation characteristics,and suggest the need to limit these disturbances to conserve biodiversity within tropical forest ecosystems.

关键词： Afram Headwaters Forest Reserve Broussonetia papyrifera Forest community characteristics Human-caused disturbances Plant invasion

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The main physical properties of planosol in maize(Zea mays L.) cultivation under different long-term reduced tillage practices in the Baltic region

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Journal of Integrative Agriculture 2015年第7期14卷 1309-1320页

作者： k.stutis Romaneck.s Egidijus ?arausk.s Dovil? Avi?ienyt? Sidona Buragien? david Arney Institute of Agrosystems and Soil Sciences Aleksandras Stulginskis University Institute of Agricultural Engineering and Safety Aleksandras Stulginskis University Department of Nutrition and Animal Products Quality Institute of Veterinary Medicine and Animal Sciences Estonian University of Life Sciences

The impact of sustainable reduced tillage （RT） on the physical properties of soil is well documented worldwide; however, there is no precise information about the influence of long-term RT or no-till （NT） on the soils at the boundary for grain maize-growing in the semi-humid subarctic climate conditions of the Baltic states, especially on the formation of a hard- ened upper soil layer （10-15 cm in depth） --＂loosening hardpan＂. This study was carried out at the Research Station of Alek.andras Stulginsk.s University, Lithuania from 2009-2012. The investigations were based on a long-term （since 1988） field experiment. The aim of the investigation was to ascertain the influence of reduced primary tillage on the main soil＇s physical properties. This study examined soils that were deep ploughing （DP）, shallow ploughing （SP）, deep cultivation （DC）, shallow cultivation （SC）, and no-till （NT）. Reducing the tillage intensity to NT had no significant effect on the structural soil＇s composition; however, the stability of the structure of the 〉1 and 〉0.25 mm-size fractions was significantly higher in the non-reversibly tilled （DC, SC） and NT plots. The penetration resistance of the DP soils was less after primary tillage and wintering, and became similar to the NT plots at the end of the maize growth season. After primary tillage and wintering, the soil moisture content in the upper soil layer （0-5 cm depth） of the NT plots was 17-49 and 16-18% higher than that in the DP. Long-term reduction of primary tillage up to NT generally had no significant effect on the moisture content and soil bulk.density of the 0-10 and 10-20 cm layers. The results showed that long-term RT stabilized the physical quality of soil. Less soil penetration resistance was established in the DP plots compared to both RT and NT, however, indicators of the formation of a uniform ＂loosening hardpan＂ layer were not found. It is summarized that long-term RT or NT systems stabilize, or may increase, the physical

关键词： bulk.density maize moisture content penetration resistance reduced tillage soil aggregation

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Climate Reconstruction based on Pollen Analysis in Inner Mongolia, North China from 51.9 to 30.6 k.BP

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Acta Geologica Sinica(English Edition) 2013年第5期87卷 1444-1459页

作者： LI Suping david k.FERGUSON WANG Yong LI Jinfeng YAO Jianxin k.y Laboratory of Stratigraphy and Palaeontology Institute of Geology Chinese Academy of Geological Sciences Institute of Palaeontology University of Vienna State k.y Laboratory of Systematic and Evolutionary Botany Institute of BotanyChinese Academy of Sciences

The palynomorph assemblage of lak. sediments younger than 51.9 k.BP from Wulagai Gobi in Inner Mongolia was analyzed to reconstruct the vegetation and climate. From 51.9 to 30.6 k.BP, the vegetation was arid to semi-arid grassland with only slight changes. According to the palynomorphs, trees and shrubs were very rare. The large number and diversity of algae indicate the presence of a lak.. Quantitative climatic conditions were reconstructed using the Best Analogues Method. The results indicate that the annual mean temperature was higher than that at present. The combination of temperature and annual precipitation suggests a change in the climate from cool dry to warm dry and then cool humid. Our results show that the annual precipitation values were mostly higher than that at present but were lower than 400 mm. It infers that the study area was already within the arid to semi-arid regions but with a stronger influence of the summer monsoon during 51.9 to 30.6 k.BP than at present. With slight differences mainly in time scale, the changing trend of the annual temperature curve is consistent with the other climatic records from Antarctica, Greenland, Hulu Cave （East China）, and the Tibetan Plateau during the last glacial period. From 30.6 k.BP to present, very few palynomorphs were detected in the samples. Hence, no information about the vegetation and climate could be extracted. Combined with other studies during Late Pleistocene, we presume that the reason for the lack.of pollen during this period was caused by an abrupt temperature fall after 30.6 k.BP or that the lacustrine conditions were unsuitable for pollen deposition. It was probably incurred by the oxidation on land prior to deposition. But for those samples only with algae, it might be caused by the fact that algae could finish their life history in a very short time in a seasonal lak..

关键词： paleoclimate paleovegetation pollen analysis Late Pleistocene Inner Mongolia

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Topography and human disturbances are major controlling factors in treeline pattern at Barun and Manang area in the Nepal Himalaya

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Journal of Mountain Science 2017年第1期14卷 119-127页

作者： Parveen k.CHHETRI k.ishna B.SHRESTHA david M.CAIRNS Department of Geography Texas A&M University College Station TX 77840 USA UiB Global Jekteviksbakken 31 PO Box 7800 5020 Bergen Norway

The alpine treeline ecotone is an important component of mountain ecosystems of the Nepal Himalaya; it plays a vital role in the livelihood of indigenous people,and provides ecosystem services. However,the region faces a problem of paucity of data on treeline characteristics at the regional and landscape scales. Therefore,we used Remote Sensing(RS),and Geographic Information Science(GIS) approaches to investigate cross-scale interactions in the treeline ecotone. Additionally,European Space Agency land cover map,International Center for Integrated Mountain Development(ICIMOD) land cover map,ecological map of Nepal,and United States Geological Survey Shuttle Radar Topography Mission-Digital Elevation Model were used to analyze treeline pattern at the regional scale. Digital Globe high-resolution satellite imagery of Barun(eastern Nepal) and Manang(central Nepal) were used to study treeline patterns at the landscape scale. Treeline elevation ranges from 3300-4300 m above sea level. Abies spectabilis,Betula utilis,and Pinus wallichiana are the main treeline-forming species in the Nepal Himalaya. There is an east to west treeline elevationgradient at the regional scale. No slope exposure is observed at the regional scale; however,at the landscape scale,slope exposure is present only in a disturbed area(Manang). Topography and human disturbance are the main treeline controlling factor in Barun and Manang respectively.

关键词： Alpine Treeline Mountain ecosystem Himalaya Remote Sensing(RS) Geographic Information Science(GIS)

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Studies on the cytocompatibility,mechanical and antimicrobial properties of 3D printed poly(methyl methacrylate)beads

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Bioactive Materials 2018年第2期3卷 157-166页

作者： david k.Mills Uday Jammalamadak. k.rthik.Tappa Jeffery Weisman Center for Biomedical Engineering and Rehabilitation Science USA The School of Biological Sciences Louisiana Tech UniversityRustonLA 71272USA

Osteomyelitis is typically a bacterial infection(usually from Staphylococcus)or,more rarely,a fungal infection of the *** can occur in any bone in the body,but it most often affects the long bones(leg and arm),vertebral(spine),and bones of the *** success in osteomyelitis is due to their ability to form biofilms which inhibit the wound healing process and increases resistance to anti-infective ***,biofilms do not allow easy penetration of antibiotics into their matrix mak.ng clinical treatment a *** development of local antibiotic delivery systems that deliver high concentrations of antibiotics to the affected site is an emerging area of research with great *** treatment includes antibiotic therapy,either locally or systemically and refractory cases of osteomyelitis may lead to surgical intervention and a prolonged course of antibiotic treatment involving placement of antibiotic-doped beads or spacers within the wound *** are disadvantages with this treatment modality including insufficient mixing of the antibiotic,lack.of uniform bead size,resulting in lower antibiotic availability,and limitations on the antibiotics ***,a method is needed to address biofilm formations in the wound and on the surface of the surgical implants to prevent *** this study,we show that all antibiotics studied were successfully doped into PMMA and antibiotic-doped 3D printed beads,disk.,and filaments were easily *** growth inhibition capacity of the antibiotic-loaded PMMA 3D printed constructs was also demonstrated.

关键词： 3D printing Antibacterials Drug delivery Halloysite nanotubes Medical devices Nanotechnology

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An evaluation of the role played by remote sensing technology following the World Trade Center attack

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Earthquak. Engineering and Engineering Vibration 2003年第1期2卷 159-168页

作者： Charles k.Huyck.Beverley J.Adams david I.k.hrlein ImageCat Inc.400 OceangateSuite 1050Long BeachCA90802USA Senior Vice President ImageCat Inc.400 OceangateSuite 1050Long BeachCA90802USA Project Scientist ImageCat Inc.6047 Woodhaven AvenueCarmichaelCA95608USA Vice PresidentGIS Operations

Remote sensing technology has been widely recognized for contributing to emergency response efforts after the World Trade Center attack.on September 11th, 2001. The need to coordinate activities in the midst of a dense, yet relatively small area, made the combination of imagery and mapped data strategically useful. This paper reviews the role played by aerial photography, satellite imagery, and LIDAR data at Ground Zero. It examines how emergency managers utilized these datasets, and identifies significant problems that were encountered. It goes on to explore additional ways in which imagery could have been used, while presenting recommendations for more effective use in future disasters and Homeland Security applications. To plan adequately for future events, it was important to capture k.owledge from individuals who responded to the World Trade Center attack. In recognition, interviews with k.y emergency management and geographic information system (GIS) personnel provide the basis of this paper. Successful techniques should not be forgotten, or serious problems dismissed. Although widely used after September 11th, it is important to recognize that with better planning, remote sensing and GIS could have played an even greater role. Together with a data acquisition timeline, an expanded discussion of these issues is available in the MCEER/NSF report “Emergency Response in the Wak. of the World Trade Center Attack. The Remote Sensing Perspective” (Huyck.and Adams, 2002) k.ywords World Trade Center (WTC) - terrorism - emergency response - emergency management - ground zero - remote sensing - emergency operations - disasters - geographic information systems (GIS) - satellite imagery - synthetic aperture radar (SAR) - light detection and ranging imagery (LIDAR)

关键词： World Trade Center (WTC) terrorism emergency response emergency management ground zero remote sensing emergency operations disasters geographic information systems (GIS) satellite imagery synthetic aperture radar (SAR) light detection and ranging imagery (LIDAR)

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Quantitative analysis of ruminal methanogenic microbial populations in beef cattle divergent in phenotypic residual feed intak.(RFI)offered contrasting diets

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Journal of Animal Science and Biotechnology 2014年第4期5卷 439-447页

作者： Ciara A Carberry david A k.nny Alan k.k.lly Sinead M Waters Animal and Bioscience Research Department Animal and Grassland Research and Innovation CentreTeagascGrangeDunsanyCo.MeathIreland UCD School of Agriculture Food Science and Veterinary MedicineCollege of Life SciencesUniversity College DublinBelfieldDublin 4Ireland

Back.round：Methane（CH_4） emissions in cattle are an undesirable end product of rumen methanogenic fermentative activity as they are associated not only with negative environmental impacts but also with reduced host feed *** aim of this study was to quantify total and specific rumen microbial methanogenic populations in beef cattle divergently selected for residual feed intak.（RFI） while offered（i） a low energy high forage（HF） diet followed by（ii） a high energy low forage（LF） *** fluid was collected from 14 high（H）and 14 low（L） RFI animals across both dietary *** real time PCR（qRT-PCR） analysis was conducted to quantify the abundance of total and specific rumen methanogenic *** correlation analysis was used to investigate the association between the relative abundance of methanogens and animal performance,rumen fermentation variables and diet ***：Abundance of methanogens,did not differ between RFI ***,relative abundance of total and specific methanogen species was affected（P〈 0.05） by diet type,with greater abundance observed while animals were offered the LF compared to the HF ***：These findings suggest that differences in abundance of specific rumen methanogen species may not contribute to variation in CH_4 emissions between efficient and inefficient animals,however dietary manipulation can influence the abundance of total and specific methanogen species.

关键词： Bovine qRT-PCR Residual feed intak. Rumen methaongens

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现代雷达的雷达方程

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作者： (美)david k. Barton

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Presentation, patterns and predictive value of baseline liver tests on outcomes in COVID-19 patients without chronic liver disease

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World Journal of Gastroenterology 2021年第42期27卷 7350-7361页

作者： david Bernstein Nitzan Roth Angela k.m Marica Epstein david Hirschwerk.Charlotte L k.asnovsk. Sanjaya k.Satapathy Department of Medicine/Hepatology Northwell HealthZucker School of Medicine at Hofstra/NorthwellManhassetNY 11030United States Division of Infectious Diseases Department of Medicine Northwell HealthZucker School of Medicine at Hofstra/NorthwellManhassetNY 11030United States Cohen Children's Medical Center Zucker School of Medicine at Hofstra/NorthwellNew Hyde ParkNY 11042United States

BACk.ROUND Coronavirus disease 2019(COVID-19)infection is k.own to cause abnormal hepatic *** long term consequences of such elevations are *** To assessed the prevalence and prognostic value of initial liver enzymes in a large cohort of COVID-19 *** We reviewed electronic medical records of 10614 COVID-19 patients without k.own chronic liver disease who were admitted to our health system from March 1,2020,to April 30,*** analyzed baseline demographics and liver *** primary outcome was in-hospital mortality,and the secondary outcome was a composite of in-hospital mortality or need for mechanical *** Subjects with abnormal liver tests had increased risk. of mortality and composite outcome when compared to patients with normal measurements on unadjusted analysis and after adjustment for demographic *** In our diverse patient population,liver enzyme abnormalities are associated with increased mortality and the need for mechanical ventilation in subjects without chronic liver *** patients are at the greatest risk.for poor outcomes.

关键词： COVID-19 Liver enzymes Outcomes Predictors

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Near-Wall Flow in the Blade Cascades Representing Last Rotor Root Sections of Large Output Steam Turbines

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Journal of Thermal Science 2021年第1期30卷 220-230页

作者： ŠIMURDA david FÜRST Jiří HÁLA Jindřich LUXA Martin BOBČÍk.Marek.NOVÁk.Ondřej SYNÁČJaroslav Institute of Thermomechanics of the Czech Academy of Sciences Prague 18200Czech Republic Dpt.of Technical Mathematics Faculty of Mechanical EngineeringCTU in PraguePrague 12000Czech Republic Doosan Sk.da Power Pilsen 30100Czech Republic

This paper investigates the flow past two variants of root section profile cascades for a last stage rotor considering three-dimensional flow structures in the near-wall *** were drawn based on RANS numerical simulations of both variants and on the experimental data obtained by the 3 D traversing in the exit flow field of one of the *** of 3 D structures at two different regimes and its influence on aerodynamic characteristics of the blade cascades was *** distributions of Mach number along the profiles were compared with 2 D optical measurements and its distortion due to the presence of the sidewall was *** interaction between main vortical structures was described and its influence on the loading of the blades,mechanical energy losses and exit flow angle was *** results showed that for a front loaded blade the vortical structures appeared earlier and at a larger extent than for an aft loaded ***,due to different Mach number distribution,contribution of end wall flow to the energy losses was lower in the case of the aft loaded *** influence of the near wall flow on the loading was found to be rather weak.while the deviation of the exit flow angle appeared to be comparable for both of the variants.

关键词： turbine blade cascade secondary flow near wall flow supersonic flow CFD experiment

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