597 resultados para braced frame


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The evaluations of the effect of the climatic conditions and of the intensity of forest management in the trunk of the Gmelina arborea Linn. Roxb. trees are restricted to its physical-mechanical properties and use. The present work has as objective to study the radial variations of the wood anatomy of the gmelina trees sampled in plantations of 30 sites in Costa Rica, characterized by two climatic conditions (tropical dry and humid) and three intensities of forest management (intensive, moderate and without management). The results of the analyses demonstrated the existence of radial variation of the different anatomical parameters, except for the fiber lumen diameter and multiple vessels in the wood of the gmelina trees. For the wood anatomical elements, fibers (width, lumen diameter, and length), vessels (multiple vessels, diameter and frequency) and radial parenchyma (height) relationships were observed with the climate (tropical humid and dry). The radial variations of the wood anatomical elements were, also, influenced by the management regimes of the gmelina trees.

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This work aimed to determining the anatomical structure of wood, through methodology of histology and X-ray densitometry, of resin-tapped and not resin-tapped Pinus caribaea var. hondurensis trees samples, of three diameter classes. Pine trees, in forest plantation established in 1969, in the Ecological Experimental Station of Itirapina, from the Forestry Institute of Sao Paulo State, were measured and stratified into three classes of trunk diameter. The pine trees were resin-tapped since 2004, with the opening of two simultaneous and opposing panels. Sixty samples of pine wood trees were extracted from the tree trunk through a non-destructive method and in the laboratory. Tree rings were determined in the laboratory and wood apparent density by X-ray densitometry. The test results showed that: (i) false tree rings occur in the early wood and late wood of the tree rings due to climate change; (ii) the X-ray densitometry allowed the demarcation of the tree rings limits; (iii) the wood apparent density average was significantly different between the trees in high class diameter and in the medium-low class; (iv) the wood characteristics from the resin-tapped and non resin-tapped faces did not show significant differences.

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Rapid deforestation in the Brazilian Amazon, caused by economic, social, and policy factors, has focused global and national attention on protecting this valuable forest resource. In response, Brazil reformed its federal forest laws in 2006, creating new regulatory, development, and incentive policy instruments and institutions. Federal forestry responsibilities are maintained within the ministry of the environment; its regulatory agency responsibilities are divided among three different branches of the agency; many powers are delegated to states and municipalities; and a new private concession system is being developed. These reforms offer promise to improve forest protection and management in Brazil but must overcome significant institutional and social resistance for success.

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Mahogany trees, Swietenia macrophylla, occur in open rainforest, semi deciduous and deciduous and dense rainforest of Peruvian Amazonian tropical forest. They occur, preferentially, in areas with a defined dry season, with typical phenology and seasonal variation activity, forming distinct tree-rings. The present work had as aim to determine the wood density radial variation of 14 mahogany trees, of two populations of the Peruvian Amazonian tropical forest, through the X-ray densitometry and to evaluate their application as methodology, compared to the classic method of measurement table, for the determination of the treering width. The radial wood apparent density of the trees profiles rendered it possible to delimit the areas of juvenile-adult wood and of the heartwood-sapwood, relative to the anatomical structure and chemical composition differences, due to the extractives and the vessels obstruction by tyloses. The mean, minimum and maximum wood apparent density of the mahogany trees for the Populations A and B were of 0.70; 0.29; 1.01 g.cm(-3) and 0.81; 0.29; 1.19 g.cm(-3), respectively. The analysis of the variance and mean test indicate differences of mean wood density among the mahogany trees of each population, probably due to the age of the trees. There was no correlation between mean wood density of mahogany trees among the two populations, as well as, between the tree-ring width and the respective mean density. The X-ray densitometry technique is an important tool in the evaluation of the radial variation of wood apparent density and the delimitation of tree-ring boundaries, with correlations of 0.94 and 0.93 in relation to measurement table, for each sampled population.

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Two species of Neocypholaelaps Vitzthum are reported from Sri Lanka. One of them, Neocypholaelaps ceylonicus Narita & Moraes, n. sp., is described based on adult females. The other, Neocypholaelaps ampullula (Berlese), originally described from Indonesia, is reported for the first time in Sri Lanka. Complementary morphological information about this species is provided based on the specimens collected in this study. A discussion is presented about the spermathecal apparatus of Neocypholaelaps species.

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The sugarcane spittlebug, Mahanarva fimbriolata (Hemiptera: Cercopidae), is considered the most important pest of sugarcane harvested without the burning of trash, or green cane, in Brazil. The objective of this work was to compare the biology of M. fimbriolata on six sugarcane varieties: SP79-1011, SP80-1816, SP80-1842, SP81-3250, RB72454, and RB835486. The experiments were conducted at a temperature of 25 +/- 1 degrees C, RH of 70 +/- 10%, and a photoperiod of 14:10 [L:D]. Variety RB72454 outperformed the rest, reducing the nymphal population that fed on its roots by 50%. With regard to adults, variety SP81-3250 allowed greater mean longevity of males (38 days) and females (51 days), greater mean oviposition period (46 days), and higher mean fecundity (1215 eggs/female); these parameters were statistically different from those obtained with other varieties. For the eggs, there was no significant effect of variety on developmental time or viability. Consequently, the variety SP81-3250 should be avoided in areas predisposed to the occurrence of M. fimbriolata.

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In a previous study, we observed no spatial genetic structure in Mexican populations of the parasitoids Chelonus insularis Cresson (Hymenoptera: Braconidae) and Campoletis sonorensis Cameron (Hymenoptera: Ichneumonidae) by using microsatellite markers In the current study, we Investigated whether for these important parasitoids of the fall armyworm (Lepidoptera: Noctuidae) there is any genetic structure at a larger scale Insects of both species were collected across the American continent and their phylogeography was Investigated using both nuclear and mitochondria] markers Our results suggest an ancient north-south migration of C insularis, whereas no clear pattern] could be determined for C sonorensis. Nonetheless, the resulting topology indicated the existence of a cryptic taxon within this later species. a few Canadian specimens determined as C. sonorensis branch outside a clack composed of the Argentinean Chelonus grioti Blanchard, the Brazilian Chelonus flavicincta Ashmead, and the rest of the C sonorensis individuals The individuals revealing the cryptic taxon were collected from Thichoplusia in (Hubner) (Lepidoptera. Noctuidae) on tomato (Lycopersicon spp) and may represent a biotype that has adapted to the early season phenology of its host. Overall, the loosely defined spatial genetic structure previously shown at a local fine scale also was found at the larger scale, for both species Dispersal of these insects may be partly driven by wind as suggested by genetic similarities between Individuals coming from very distant locations.

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A new species, Neocypholaelaps geonomae n. sp., is described based on the morphology of adult females and males collected on Geonoma spp. (Arecaceae) in southeastern Brazil. This is the first species of this genus identified from the American continent. A key to the world species of Neocypholaelaps is provided.

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Four new species of Anastrepha Schiner were collected in McPhail-type traps hung in trees in a natural reserve and in commercial papaya orchards in Linhares, Espirito Santo state, Brazil. They are described and named herein as follows: Anastrepha atlantica n. sp., Anastrepha glochin n. sp., Anastrepha linharensis n. sp. and Anastrepha martinsi n. sp. Only the latter was collected in traps hung in papaya orchards. The classification of these species in species groups of Anastrepha is also discussed.

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On Mho obesa F. (Diptera: Syrphidae) is usually neglected in forensic entomology, although adults are rather frequent on vertebrate carrion. In this study, conducted in southeastern Brazil in 2008, we used two pig carcasses, one killed by cocaine overdose and the other by shooting, to evaluate mainly the possible influences of the type of death on the larval development of O. obesa in the pig remains. We recorded the breeding of 218 adult specimens of this syrphid fly from the carcass killed by shooting, and none from the carcass killed by cocaine. These observations may open a new perspective for the use of O. obesa in forensic studies, considering its breeding preferences and its complete development on vertebrate carrion.

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Gamasiphis paulista n. sp. is described based on specimens representing all postembryonic stages, collected from litter and soil in Piracicaba, State of Sao Paulo. This is the first species of Gamasiphis described from Brazil. A key is provided for the separation of species of this genus known from the Neotropical Region.

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The phytoseiid mites of the Dominican Republic are virtually unknown. In a survey conducted in areas of natural vegetation of that country, 23 species were collected, two of which, Phytoseius dominicensis Ferragut & Moraes sp. nov. and Typhloseiopsis adventitius Ferragut & Moraes sp. nov., are new to science. We report the species found in that survey, describe the two new species, and provide complementary morphological information about other species. To accommodate the new Typhloseiopsis De Leon species, a redefinition of Typhloseiopsis is proposed. A key for the separation of the species in this genus is provided.

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Diaphorina citri Kuwayama (Hemiptera: Psyllidae) is the vector of the bacteria that causes citrus greening and is considered one of the world`s most important citrus diseases. We examined how host, geographic region, and gender affect the thermal requirements of D. citri. The insects were reared in climatic chambers at constant temperatures of 18, 20, 22, 25, 28, 30, and 32 1 degrees C, 70 +/- 10% RH, and a 14 h photophase. Host plants for D. citri included orange (Citrus sinensis [Rutaceae]) varieties Pera and Natal, the rootstock, Rungpur lime (C. limonia [Rutaceae]) and the natural host, Orange jessamine (Murraya paniculata [Rutaceae]). To study the influence of geographic origin on thermal requirements, we studied D. citri populations from Piracicaba, SP (warmer region) and Itapetininga, SP (cooler region). The duration and survival of the development stages and the duration of the total development (egg-adult) did not differ significantly on the different hosts, but it did vary with temperature. Nymphs of D. citri created on the different hosts have the same thermal requirements. The thermal requirements for this species collected from the two climate regions were identical; males and females also had the same thermal requirements.

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This research was carried out to evaluate and compare 11 organic honey samples and six non organic honey samples, respectively, harvested from islands of the triple frontier (Sao Paulo, Parana and Mato Grosso do Sul states) and from the state of Parana, Brazil. The samples were studied for the presence of coliforms from 35 degrees C, to 45 degrees C and the enumeration of moulds and yeast, a minimum of 1.9 x 10(2) and a maximum of 1.1 x 10(3) CFU/g were observed in organic honey and a minimum of 1.8 x 10(1) and a maximum of 2.5 x 10(2) CFU/g were in non organic honey. In this studied region, the organic honey presented a microbiological quality inferior to the non organic honey.

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This is the ninth publication in a series on the taxonomy of phytoseiid mites of sub-Saharan Africa. Sixty-five phytoseiid species of the tribe Typhlodromini Wainstein, all of which are in the genus Typhlodromus Scheuten are reported in this paper (62 in the subgenus Anthoseius DeLeon and 3 in the subgenus Typhlodromus Scheuten). They refer to all species of this tribe known to occur in sub-Saharan Africa. Fifteen new species are described and 41 species are redescribed. Most of the reported species were collected in various habitats in southern Africa and in cassava habitats in tropical Africa. A key is included for the separation of these species.