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The Impact of Encroachment on the Distribution of Tree Species in Cross River National Park, Oban Division, Nigeria

Journal of Environmental Protection 2015年第7期6卷 744-754页

作者： Margaret A. Yaro Department of Urban and Regional Planning Cross River University of Technology Calabar Nigeria

Increasing human activities around protected area pinpoint to looming degradation and alteration of the component of such areas, especially where adequate measures are not taken to forestall encroachment. The Oban division of the Cross River National Park is one of the oldest rainforests and has been identified as a biodiversity hotspot. However, communities settling around the park have been involved in some economic activities for their livelihood. Resource utilization at the edge of the park may alter the components of the park such as species diversity. Therefore this study is geared towards assessing the impact of human encroachment and the concomitant impact on the distribution of species within the park. The study adopted participatory research methods which included Focus Group Discussion and participatory mapping as well as a plot based survey which involved the laying of sample plots within two zones of the park designated as areas bounded by cultivated land and areas bounded by fallow. Three 40 m × 40 m square plots are laid along a 320 meter transect measured from the boundary of the park at each buffer zone. The plots are separated by 100 m gap. From the result obtained, it is discovered that Musanga cercropoides dominates the outer plots of the cultivated zones and fallow zones comprising 20.2 and 21.5 percent respectively while Terminalia ivorensis dominates the middle and inner areas of the park. Moreover the composition of species decreases inward to the inner part of the park. Diversity index decreases in the order of 2.566 zones and 2.443 zones. It is concluded that human activities close to the park alters the species composition of the park. Hence, it’s recommended that adequate alternatives livelihood and incentive be provided to support zone communities to reduce their dependents on the edge of the park.

关键词： Park Encroachment Impact Diversity Colonizers zones

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Dust pollen distribution on a continental scale and its relation to present-day vegetation along north-south transects in east China

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Science China Earth Sciences 2007年第2期50卷 236-246页

作者： P. COUR D. DUZER G. ROBERT M. CALLEJA C. BEAUDOUIN Ecole Nationale Supérieure Agronomique de Montpellier 34000 Montpellier France UMR CNRS 5554 ISEM Université Montpellier 2 34000 Montpellier France Department of Earth Sciences Sun Yat-sen University

A series of dust pollen samples was collected along N-S transects in east China (18°N to 53°N latitudes). Sample sites extend from the cold-temperate zone in the north to the tropical region in the south. Pollen taxa characterize each region and reflect the natural and devastated vegetation as well as corre- sponding climatic zones. The quantitative pollen data can be used to estimate the spatial distribution of planted and introduced species. Valuable information of human disturbance of the natural forest is evaluated by quantitative comparison between dust pollen and in-situ pollen of protected forest. In addition, percentages of grass pollen vary regularly from north to south that is consistent with spatial distribution of net primary productivity in east China. Among all grasses, Artemisia and the Gramineae carry the clearest signal: their ratio increases northwards and therefore represent a suitable and con- venient tool for palaeoclimate reconstructions.

关键词： dust pollen vegetation east China human impact climate zones

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Electrical Resistivity Imaging of Suspected Seepage Channels in an Earthen Dam in Zaria, North-Western Nigeria

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Open Journal of Applied Sciences 2013年第1期3卷 145-154页

作者： Ani D. Chinedu Arewa J. Ogah Department of Mathematics Statistics and Computer Science College of Science and Technology Kaduna Polytechnic Kaduna Nigeria Department of Physics Kogi State University Anyigba Nigeria

To determine and map the subsurface conditions of a dam, a 2D electrical resistivity tomography study was carried out within the two flanks of Zaria dam at Shika. This was done to ascertain if the variations in the volume of water content in the dam is due to an anomalous seepage beneath the subsurface or seasonal effects. On the basis of the interpretation of the acquired data, various zones of relatively uniform resistivity values were mapped and identified. The first zone is characterized by moderate resistivity values of 150 - 600 ohm-m. It represents unsaturated topsoil with thicknesses varying from 1 - 4.5 m. The second (intermediate depth) resistivity zone, with values ranging from 5 - 100 ohm-m and thickness varying from 3.5 - 10 m, represents a silt clay layer with high moisture content. The third resistivity zone represents fairly weathered granite and is characterized by relatively high resistivity values ranging from 700 - 6000 ohm-m. The available borehole log data correlated well with the pseudo-sections in relation to the obtained resistivity values and depth. zones of relatively low resistivity within the bedrock are interpreted to represent potential seepage pathways. Hence, this geophysical method can be successfully used to delineate and map these seepage pathways within the subsurface of the earth dam.

关键词： Anomalous Seepage Earthen Dam Unconsolidated Formations Loose Ground Saturated zones

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Ground Penetrating Radar Survey of Dam Structures of Kazakhstan on example of Aktobe and Karatomar Water Storage Basins

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Open Journal of Geology 2013年第2期3卷 25-27页

作者： Zhumabek Zhantayev Baurzhan Kurmanov Nikolai Breusov Shigayev Dauren Kirsanov Alexandr Department of Geophysical and Geodynamic Monitoring LLP “Institute of Ionosphere” Almaty Kazakhstan

Ground penetrating radar surveys of technical condition of Karatomar and Aktobe water storage basins on the river Tobol are shown. In this article we have shown that dams have problems with cavities and identified lon... 详细信息

关键词： Ground Penetrating Radar (GPR) Hydraulic Structures Anomalous zones Dam Decompression Zone Areas of High Humidity

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Biopharmaceutical Assessment of Active Components of <i>Deadaleopsis confragosa</i>and <i>Ganoderma lucidum</i>

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Open Journal of Medical Microbiology 2013年第2期3卷 135-138页

作者： Soji Fakoya Kehinde Tope Adegbehingbe Aderinola Adedamola Ogundiimu Department of Biological Sciences Joseph Ayo Babalola University Ikeji-Arakeji Nigeria Department of Biological Sciences Ondo State University of Science and Technology Okitipupa Nigeria Department of Microbiology Adekunle Ajasin University Akungba Akoko Nigeria

The spread of multidrug-resistant strains of bacteria makes it necessary to discover new classes of antibacterial and compounds that inhibit these resistant mechanisms. Hence, this study investigated the antimicrobial activities of Ganoderma lucidum and Deadaleopsis confragosa extracts against some bacterial isolates of medical importance. Using agar well diffusion assay, aqueous, ethanolic and petroleum ether extracts were obtained from Ganoderma lucidum and Daedaleopsis confragosa and assayed for antimicrobial on five bacterial species, viz: Pseudomonas aeruginosa, Escherichia coli, Staphylococcus aureus, Proteus mirabilis and Klebsiella pneumoniae. In vitro bioassay revealed that the aqueous extract of G. lucidum inhibited P. aeruginosa S. aureus, E. coli and K. Pneumoniae with inhibition zones of 11.0 ± 0.02 mm, 10.0 ± 0.02 mm, 13.0 ± 0.03 mm and 14.0 ± 0.0 mm respectively. The ethanolic extract of G. lucidum also inhibited P. aeruginosa, S. aureus and E. coli with inhibition zones 12.0 ± 0.01 mm, 11.0 ± 0.02 mm and 16.0 ± 0.01 mm. Petroleum ether extract of G. lucidum inhibited P. aeruginosa, S. aureus and E. coli with inhibition zones of 12.0 ± 0.01 mm, 11.0 ± 0.03 mm and 12.0 ± 0.02 mm. For Daedaleopsis confragosa, the aqeous extract inhibited P. aeruginosa and E. coli with inhibition zones of 12.0 ± 0.01 and 12.0 ± 0.02 mm respectively while the petroleum ether extract inhibited S. aureus and E. coli with inhibition zones of 19.0 ± 0.02 mm and 13.0 ± 0.01 mm respectively. All these inhibitions on clinical isolates are therefore attributed to the presence of some bioactive compound as shown by the phytochemical screening of the mushrooms which include tannins, phenolics, flavonoids and saponin.

关键词： Ganoderma lucidum Deadaleopsis confragosa Antimicrobials Inhibition zones Phytochemicals

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Study on Peat-Forming Mechanism of Tropic and Sub-TropicTidal Flats

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International Journal of Mining Science and Technology 1997年第2期18卷 51-55页

作者：桑树勋刘焕杰施健

Tropic and sub-tropic tidal flats (generalised) are a kind of speific peat-forming environments. Taking the Mangrove tidal flats and mangrove pets in Hainan island as a example, the authors deeply study and discuss the peat-forming mechanism of tropic and sub-tropic tidal flats. The conclusions are as follows: intrusion accretiou of plant organic matter is more important ; the organic matter has accumulated witk high productivity, high return rate and high decompeition rate ;anaerobic bacterin play a more important role during early peatification ; sea level change is the fundameutal factor controlling the formation and evolution of tidal flat peat-forming environments; lagoon peat-flat and delta peat-flat are main types of tidal flat peat-forming euvironments ;tidal flat peat-forming environments are remarkably characterized by low-level and rabe properties.

关键词： mangrove tidal flat mangrove peat peat-forming mechanism tropic and subtropic zones

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Performance Assessment of Islanding Detection for Mul-ti-inverter Grid-connected Photovoltaic Systems

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Energy and Power Engineering 2013年第4期5卷 1517-1520页

作者： Xing Zhang Dong Xie College of Electric and Automation Hefei University of Technology Hefei China

Islanding detection is an essential function for safety and reliability in grid-connected Distributed Generation Systems (DGS). Passive and active islanding detection methods have been analyzed in literature considering DGS with only one inverter connected to the utility. With the big scale application of photovoltaic (PV) power systems, islanding detection technology of multi-inverter DGS has been paid more attention. This paper analyzes the performance of diverse islanding detection methods in multiple inverters grid-connected PV systems. Non-Detection zones (NDZ) of multi-inverter systems in a load parameter space are used as analytical tool. The paper provides guidance for the islanding detection design in multiple grid-connected inverters.

关键词： Photovoltaic Power Systems Islanding Detection Multi-inverter Non-Detection zones

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2D metamaterials coherently steer nonlinear valley photons of 2D semiconductor

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Journal of Semiconductors 2019年第6期40卷 2-2页

作者： Chuanbo Li Ming Li School of Science Minzu University of China Beijing China Institute of Semiconductors CAS Beijing China

Monolayer transition-metal dichacolgenides (TMDCs) present a direct optical bandgap at the Brillouin zones, socalled valleys. Those energetically degenerate valleys (K and K’) present different valley pseudospins, emitting the valley photons with opposite spin angular momentums due to nonlinear optical selection rules. Furthermore, although atomically thin, two-dimensional (2D) TMDCs have giant nonlinearity, which can be enhanced by the valley-excitons.

关键词： 2D semiconductor transition-metal dichacolgenides(TMDCs) Brillouin zones

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Sources of Resistance to Blast Disease(Pyricularia grisea L.)in Finger Millet(Eleusine Coracana)Germplasm

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Journal of Life Sciences 2019年第1期13卷 34-47页

作者： C.M.Wekesa P.K.Kimurto C.O.Oduori B.K.Towett L.Jeptanui H.Ojulong E.Manyasa M.Siambi Department of Crops Horticulture&SoilsEgerton UniversityP.O.Box 536-20115EgertonKenya Kenya Agricultural Research and Livestock Organization(KALRO) P.O.Box465 KisiiKenya International Crops Research Institute for the Semi-Arid Tropics(ICRISAT) P.O.Box 39063-00623NairobiKenya

Blast has been a continuous threat to finger millet production in semi-arid *** disease is economically important and widespread in finger millet major growing areas of western,Nyanza and Rift valley in *** resistance is the most economical and effective means of controlling the disease as finger millet is grown by resource-poor *** study evaluated a hundred finger millet genotypes for resistance to blast at KALRO(Kenya Agricultural Research and Livestock Organization)Kakamega and Alupe,Kenya for two seasons in 2011/2012 in a lattice square design for two seasons *** on blast incidence and severity were *** were analyzed using ANOVA(analysis of variance)and means separated using Duncan multiple range test(DMRT)at p<*** results showed that disease severity was highest in early maturing varieties and lowest in the late maturing *** most resistant genotypes were:GBK000702,GBK000513,GBK029869,GULU-E,GBK000752 and *** correlation analysis between neck severity and physiological maturity was positively significant(r=-0.47).A strong positive correlation between finger severity and neck severity(r=0.87)was *** tolerant genotypes could be utilized as donor parents for breeding durable blast resistant varieties.

关键词： Eleusine coracana incidence Pyricularia grisea severity mid altitude zones

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Seasonal Variability in the Distribution of Phytoplankton in Paracas Bay/Peru, as a Response to Environmental Conditions

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Journal of Environmental Science and Engineering(B) 2019年第1期8卷 7-16页

作者： Sonia Sánchez Nelly Jacobo Avy Bernales Augusto Franco Jorge Quispe Georgina Flores Laboratory of Phytoplankton and Primary Production Instituto del Mar del Peru Chucuito Callao 07001 Peru Functional Area of Research in Physical Oceanography Instituto del Mar del Peru Chucuito Callao 07001 Peru Functional Area of Research in Chemical Oceanography Instituto del Mar del Peru Chucuito Callao 07001 Peru

During 2013-2015, a series of bio-oceanographic surveys was carried out in Paracas bay (13°50′ S). This coastal habitat represents a transition between open ocean and continent. Changes in distribution and structure of phytoplankton community and presence of noxious algal blooms were evaluated. The vertical stability of water column was analyzed on transects of temperature, salinity and potential density. Stratification of the water column as well as other variables presented a seasonal behavior. The maximum values were recorded in summer and were directly related to the seasonal heat flux in surface layers of the bay, while in winter this stratification index was minimum. N/P ratios showed a seasonal variation with highest values in winter and lowest ones in summer. Silicate concentrations were minimum mainly during in spring due to high biological fixation. The dominance of diatoms was evident in winter and spring, with maximum abundances of r strategists. The diversity and equitability indexes were low (< 3 bits?cel^-1 and 0.31, respectively). During summer, there was a greater contribution of oceanic species, with high concentrations of the dinoflagellate Prorocentrum cordatum;and a higher frequency of algal blooms (Akashiwo sanguinea, Heterosigma akashiwo, Eutreptiella gymnastica and Gonyaulax polygramma) in the coastal zone. Silicates and pH presented a significant correlation with diatom abundances in spring, whilst dinoflagellates were associated to warm and salinity conditions in summer. Weak correlations were found for potentially toxic dinoflagellates with temperature and for Pseudo-nitzschia group with silicates and phosphates.

关键词： HAB transition zones inshore ecosystem Paracas bay-Peru phytoplankton

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