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| Registros recuperados: 138 | |
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| Gyedu-Ababio, T.; Furstenberg, J.P.; Baird, D.J.; Vanreusel, A.. |
| Nematodes from the sediments of the Swartkops estuary in Port Elizabeth, South Africa were investigated at 10 selected sites along a salinity gradient in the subtidal region at neap tide. The relation between nematode density, genera, community structure and environmental parameters including concentrations of seven heavy metals, Mn, Ti, Cr, Pb, Fe, Sn and Zn in the sediment were investigated. The nematode community structure was significantly influenced by the chlorophyll a concentration and sediment particle-size distribution. The number of genera had significant negative correlation with chlorophyll a and two heavy metals, Fe and Zn in the sediment. The habitat preferences of the genera were also assessed. A combination of the Shannon-Wiener Diversity... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Check lists; Density; Diversity; Ecology; Meiobenthos; Pollution; Sediment; Sediments; Nematoda [Nematodes]. |
| Ano: 1999 |
URL: http://www.vliz.be/nl/open-marien-archief?module=ref&refid=7328 |
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| Zaque, Leonardo Antônio Moraes; Ferreira, Mayra Daniela; Melo, Rafael Rodolfo. |
| A massa específica da madeira é uma das propriedades mais importantes do ponto de vista prático, sendo utilizada como principal indicador para diversos tipos de uso. No entanto, mesmo se tratando de uma única espécie, esse parâmetro pode variar ao longo do fuste, seja no sentido base-topo e/ou medula-casca. Deste modo, a sua determinação torna-se essencial para qualificação da madeira de qualquer espécie florestal. O presente estudo teve como objetivo avaliar as variações radial e longitudinal da massa específica básica da madeira de Araucaria angustifolia (Bert.) O. Kuntze. para indivíduos de diferentes idades. Para isso, foram abatidas doze árvores com as idades de 23, 25, 28 e 30 anos. Foram retirados discos a 10%, 35%, 55% e 75% da altura total de cada... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Propriedades físicas; Medula; Densidade Physical properties; Pith; Density. |
| Ano: 2018 |
URL: http://pfb.cnpf.embrapa.br/pfb/index.php/pfb/article/view/1368 |
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| Sbrissia,André Fischer; Silva,Sila Carneiro da; Matthew,Cory; Carvalho,Carlos Augusto Brandão de; Carnevalli,Roberta Aparecida; Pinto,Luiz Felipe de Moura; Fagundes,Jaílson Lara; Pedreira,Carlos Guilherme Silveira. |
| The objective of this study was to evaluate the occurrence of the tiller size/density compensation mechanism in Tifton 85 bermudagrass swards grazed by sheep under continuous stocking. Treatments corresponded to four sward steady state conditions (5, 10, 15, and 20 cm of sward surface height), maintained by sheep grazing. The experimental design was a complete randomized block with four replicates. Pasture responses evaluated include: tiller population density, tiller mass, leaf mass and leaf area per tiller, and herbage mass. Tiller volume, leaf area index, tiller leaf/stem ratio, and tiller leaf area/volume ratio were calculated and simple regression analyses between tiller population density and tiller mass were performed. Measurements were made in... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Cynodon; Leaf area index; Mass; Density; Plant morphology. |
| Ano: 2003 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-204X2003001200013 |
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| Silva,Cleonor Cavalcante; Laumann,Raul Alberto; Blassioli,Maria Carolina; Pareja,Martin; Borges,Miguel. |
| The objective of this work was to improve the mass rearing technique of Euschistus heros in laboratory. Nymphs and adults were reared at densities 100, 200, 300 and 400 eggs per Petri dish (9 cm diameter), and at 50, 100, 150 and 200 couples per rearing cages (900 mL), respectively. Survival rate of immature stages and survivorship and reproduction of adults were determinated. Survivorship of nymph to adult was the highest (89%) at density 100 eggs per dish. Adult survivorship was independent of density, and 100 couples per cage were the best to improve quality of the produced progeny. In these conditions, fecundity was 160.8±9.28 eggs per female, and a total of 8,950±456 eggs per cage per month was produced. Two hundred couples per cage showed a negative... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Biological control; Density; Egg parasitoid; Neotropical brown stink bug. |
| Ano: 2008 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-204X2008000500004 |
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| Chaim,Aldemir; Pessoa,Maria Conceição Peres Young; Camargo Neto,João; Hermes,Luiz Carlos. |
| The main objective of this work was to compare two methods to estimate the deposition of pesticide applied by aerial spraying. Hundred and fifty pieces of water sensitive paper were distributed over an area of 50 m length by 75 m width for sampling droplets sprayed by an aircraft calibrated to apply a spray volume of 32 L/ha. The samples were analysed by visual microscopic method using NG 2 Porton graticule and by an image analyser computer program. The results reached by visual microscopic method were the following: volume median diameter, 398±62 mum; number median diameter, 159±22 mum; droplet density, 22.5±7.0 droplets/cm² and estimated deposited volume, 22.2±9.4 L/ha. The respective ones reached with the computer program were: 402±58 mum, 161±32 mum,... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Agricultural chemicals; Aerial application; Application methods; Density; Volume. |
| Ano: 2002 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-204X2002000400010 |
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| Concenço,G.; Tomazi,M.; Correia,I.V.T.; Santos,S.A.; Galon,L.. |
| In simple terms, a phytosociological survey is a group of ecological evaluation methods whose aim is to provide a comprehensive overview of both the composition and distribution of plant species in a given plant community. To understand the applicability of phytosociological surveys for weed science, as well as their validity, their ecological basis should be understood and the most suitable ones need to be chosen, because cultivated fields present a relatively distinct group of selecting factors when compared to natural plant communities. For weed science, the following sequence of steps is proposed as the most suitable: (1) overall infestation; (2) phytosociological tables/graphs; (3) intra-characterization by diversity; (4) inter-characterization and... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Weed community; Density; Frequency; Dominance; Diversity; Similarity. |
| Ano: 2013 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-83582013000200025 |
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| ABDULLAH,Y.; BALOCH,M.S.; SHAH,A.N.; HASHIM,M.M.; NADIM,M.A.; ULLAH,G.; KHAN,A.A.; SHAHZAD,M.F.. |
| ABSTRACT: The present study was to assess the additive effects of cuscuta (akasbel) aqueous extract alone and in combination with full and reduced doses of commercially available weedicides against weeds in wheat crop during the year 2016-2017. The study was conducted in a randomized complete block design (RCBD) with 3 replications. The results showed that hand weeding and use of weedicides Allymax and Axial (full and half recommended doses) significantly controlled all prevailing weeds and increased yield and yield contributing parameters over the weedy check/control and sole application of cuscuta aqueous extract. Hand weeding and Allymax (full dose) showed minimum weed population, relative density, fresh and dry weed biomass and higher leaf area index... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Wheat; Weedicides; Management; Density. |
| Ano: 2020 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-83582020000100230 |
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| Ronchi,C.P.; Silva,A.A.. |
| The effects of competition of seven weed species on the growth of coffee plants were evaluated under greenhouse conditions. Thirty days after coffee seedling transplantation into 12 L pots with soil level area of 6.5 dm², weeds were transplanted into or sown in those pots, at densities of 0, 1, 2, 3, 4 and 5 plants per pot. Competition or weedy periods from weed transplantation or emergence to plant harvesting, at weed pre-flowering stage, were: 77 days - Bidens pilosa, 98 days - Brachiaria decumbens, 180 days - Commelina diffusa, 82 days - Leonurus sibiricus, 68 days - Nicandra physaloides, 148 days - Richardia brasiliensis and 133 days - Sida rhombifolia. Coffee plant height, stem diameter, leaf number and shoot dry matter were determined. Effects of... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Density; Coffea arabica; Competition; Weedy period. |
| Ano: 2006 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-83582006000300001 |
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| Casadei,Eloisa; L. Bacha,Allan; S. Rodrigues,Juliana; S. Santos,Renata T.; L.C.A. Alves,Pedro; B.C. Filho,Arthur. |
| Abstract Background: Lettuce-production areas in Brazil are frequently infested by pigweed plants, which can interfere with production by competing for resources or releasing allelopathic compounds in the environment. Objective: The present study evaluated the effect of redroot pigweed (Amaranthus retroflexus) density and distribution on lettuce crop (Lactuca sativa L.). Methods: The cultivars Lídia, Verônica, Lucy Brown and Salad Bowl were used. After transplanting, these plants coexisted until harvest with four pigweed plants (equivalent to 16 plants m-2) located within or outside planting rows, or with one pigweed plant located at the center of the plot (4 plants m-2), as well as a control without weed. The experiment was conducted in an open and... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Lactuca sativa L.; Amaranthus retroflexus; Competition; Weeds; Density; Distribution. |
| Ano: 2020 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-83582020000100308 |
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| REHMAN,A.; QAMAR,R.; SAFDAR,M.E.; JAVEED,H.M.R.; SHEHZAD,M.; ALI,M.; ASIF,M.; TARAR,Z.H.; AHMED,A.; JAMIL,M.. |
| ABSTRACT: Weed-induced yield loss in wheat crop is a great threat to food security in Pakistan. A comprehensive understanding of weed-crop competition is very important to develop sustainable and cost-effective weed management. For this purpose, two-year field studies were conducted to determine the effect of different blessed milkthistle densities on the phenology and yield of wheat crop in a rice-wheat cropping scheme in Sargodha, Pakistan during 2013-2014 and 2014-2015. The experiment comprised seven treatments: control (weed free), weedy check (weedy without any control) and blessed milkthistle densities of 5, 10, 15, 20 and 25 plants m-2. In response to increasing weed density, a gradual reduction in yield and yield-related traits of wheat was noted.... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Blessed milkthistle; Density; Phenology; Rice-wheat cropping systems; Yield. |
| Ano: 2020 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-83582020000100210 |
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| DIESEL,F.; TREZZI,M.M.; GALLON,M.; MIZERSKI,P.H.F.; BATISTEL,S.C.; PAGNONCELLI,F.B.. |
| ABSTRACT: Weed species is one of the factors contributing to grain yield losses due to crop-weed competition. Two of the most common weeds of soybean fields in Brazil are from the Rubiaceae family: Borreria latifolia and Richardia brasiliensis. This study aimed to evaluate the effects of B. latifolia and R. brasiliensis on plant development, yield components, and soybean productivity. Two assays were conducted in a randomized block design with four replications, using a two-level factorial design, in which the first factor consisted of the species B. latifolia and R. brasiliensis and the second factor consisted of the densities 0, 2, 4, 6, 8, 10, and 12 plants m-2. Plant height, leaf area and total chlorophyll in the V6 and R5 stages, number of pods per... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Interspecific competition; Glycine max; Richardia brasiliensis; Borreria latifolia; Density. |
| Ano: 2020 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-83582020000100222 |
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| Soltani,E; Soltani,A; Galeshi,S; Ghaderi-far,F; Zeinali,E. |
| Volunteer canola (Brassica napus) and Sinapis arvensis are well identified weeds of different cropping systems. Quantitative information on regarding seed production by them is limited. Such information is necessary to model dynamics of soil seed banks. The aim of this work was to quantify seed production as a function of the size of those weeds. A wide range of plant size was produced by using a fan seeding system performed at two sowing dates (environments). Plant size varied from 3 to 167 g per plant for canola and from 6 to 104 g per plant for S. arvensis. Seed production ranged from 543 to14,773 seeds per plant for canola, and from 264 to 10,336 seeds per plant for S. arvensis. There was a close relationship between seed production per plant and plant... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Weed; Plant size; Density; Planting. |
| Ano: 2011 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-83582011000300003 |
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| McConnell, Virginia D.; Kopits, Elizabeth; Walls, Margaret. |
| This paper examines transferable development rights (TDRs) policies as a way to preserve farmland and change the density of development. Characteristics of TDR markets are described, including why they might promote efficiency, and the difficulties that arise in implementing them. Evidence from an established TDR program in Calvert County, Maryland, is used to assess the potential for TDRs to influence subdivision density, and to achieve local land preservation goals. The Calvert program has succeeded in creating an active and stable TDR market, and has therefore preserved a large amount of farmland in the region. But we find that the demand for additional density permitted with TDRs occurs mostly in rural areas and not in the higher density town centers... |
| Tipo: Journal Article |
Palavras-chave: Land preservation; Development; Markets; Density; Land Economics/Use. |
| Ano: 2005 |
URL: http://purl.umn.edu/10240 |
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| Kopits, Elizabeth; McConnell, Virginia D.; Walls, Margaret. |
| Many economists see current land use patterns as inefficient due to various market failures, and planners argue that current patterns do not follow sound planning practice. One policy of interest to both groups is transferable development rights (TDR). TDRs allow the development rights from land that is preserved in an undeveloped state to be transferred to other areas where development can be made denser. This paper addresses one of the greatest difficulties TDR programs face-insufficient demand. We develop a simple theoretical model and estimate a TDR demand function using data from Calvert County, Maryland, one of the only regions where data on individual sales are available. We find that baseline zoning is a critical determinant of TDR demand- demand... |
| Tipo: Working or Discussion Paper |
Palavras-chave: TDRs; Density; Zoning; Subdivisions; International Development; R14; R52; R21. |
| Ano: 2005 |
URL: http://purl.umn.edu/10880 |
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| Rocha,Pedro Luís B. da; Queiroz,Luciano P. de; Pirani,José Rubens. |
| One dune habitat in the semi-arid Caatinga Biome, rich in endemisms, is described based on plant species composition, woody plant density, mean height and phenology and a multivariate analysis of the micro-habitats generated by variables associated to plants and topography. The local flora is composed mainly by typically sand-dweller species of Caatinga, suggesting the existence of a phytogeographic unity related to the sandy areas in the Caatinga biome, which seems to be corroborated by faunal distribution. Moreover, some species are probably endemic from the dunes, a pattern also found in vertebrates. The plant distribution is patchy, there is no conspicuous herbaceous layer and almost 50% of the ground represents exposed sand. Phenology is not... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Density; Endemic species; Phenology; Phytogeography; Semiarid. |
| Ano: 2004 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-84042004000400013 |
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| Schmidt,GS. |
| This study included 35 farmers contracted by a broiler integrator company. Each farmer owned an average of seven poultry houses, housing six flocks per year per farmer, summing up 4.0 million broilers housed. Live performance was evaluated in flocks housed in three densities (D1<12, 12<D2<14, and D3>14 birds/m2), and included the following parameters: market age (MA), average flock weight (AFW), average daily gain (DWG), feed conversion ratio (FCR), livability (LB), production efficiency index (PEI) and carcass yield/m2 (CY). Production costs and gross margin were calculated with birds housed at two densities (11.5<D4<12.4 and 14.5<D5<15.5birds/m2), standardizing MA to 44 days. The economic evaluation included 15 farmers and 1.0... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Broilers; Density; Economic indices; Integration; Performance parameters. |
| Ano: 2008 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1516-635X2008000300002 |
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| Registros recuperados: 138 | |
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