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101.
A key challenge in modern wildfire mitigation and forest management is accurate mapping of forest fuels in order to determine spatial fire hazard, plan mitigation efforts, and manage active fires. This study quantified forest fuels of the montane zone of Boulder County, CO, USA in an effort to aid wildfire mitigation planning and provide a metric by which LANDFIRE national fuel maps may be compared. Using data from 196 randomly stratified field plots, pre-existing vegetation maps, and derived variables, predictive classification and regression tree models were created for four fuel parameters necessary for spatial fire simulation with FARSITE (surface fuel model, canopy bulk density, canopy base height, and stand height). These predictive models accounted for 56–62% of the variability in forest fuels and produced fuel maps that predicted 91.4% and 88.2% of the burned area of two historic fires simulated in the FARSITE model. Simulations of areas burned based on LANDFIRE national fuel maps were less accurate, burning 77.7% and 40.3% of the historic fire areas. Our results indicate that fuel mapping efforts that utilize local area information and biotic as well as abiotic predictors will more accurately simulate fire spread rates and reflect the inherent variability of forested environments than do current LANDFIRE data products. 相似文献
102.
Ibrom A Oltchev A June T Kreilein H Rakkibu G Ross T Panferov O Gravenhorst G 《Tree physiology》2008,28(4):499-508
Photosynthetically active radiation (Q)-use efficiency (epsilon) is an important parameter for deriving carbon fluxes between forest canopies and the atmosphere from meteorological ground and remote sensing data. A common approach is to assume gross primary production (P(g)) and net primary production (P(n)) are proportional to Q absorbed by vegetation (Q(abs)) by defining the proportionality constants epsilon(Pg) and epsilon(Pn) (for P(g) and P(n), respectively). Although remote sensing and climate monitoring provide Q(abs) and other meteorological data at the global scale, information on epsilon is particularly scarce in remote tropical areas. We used a 16-month continuous CO(2) flux and meteorological dataset from a mountainous tropical rain forest in central Sulawesi, Indonesia to derive values of epsilon(Pg) and to investigate the relationship between P(g) and Q(abs). Absorption was estimated with a 1D SVAT model from measured canopy structure and short wave radiation. The half-hourly P(g) data showed a saturation response to Q(abs). The amount of Q(abs) required to saturate P(g) was reduced when water vapor saturation deficit (D) was high. Light saturation of P(g) was still evident when shifting from half-hourly to daily and monthly time scales. Thus, for a majority of observations, P(g) was insensitive to changes in Q(abs). A large proportion of the observed seasonal variability in P(g) could not be attributed to changes in Q(abs) or D. Values of epsilon(Pg) varied little around the long-term mean of 0.0179 mol CO(2) (mol photon)(-1) or 0.99 g C MJ(-1) (the standard deviations were +/- 0.006 and +/- 0.0018 mol CO(2) (mol photon)(-1) for daily and monthly means, respectively). In both cases, epsilon(Pg) values were more sensitive to Q(abs) than to daytime D. These findings show that the current epsilon-approaches fail to predict P(g) at our tropical rain forest site for two reasons: (1) they neglect saturation of P(g) when Q(abs) is high; and (2) they do not include factors, other than Q(abs) and D, that determine seasonality and annual sums of P(g). 相似文献
103.
This paper describes the research work carried out on Octopus vulgaris reproduction at Maricoltura di Rosignano Solvay, Italy, during the period 2002–2007. Already in the first few years, it was possible to establish healthy broodstock groups, starting from subadults captured in the wild. Obtaining numerous viable eggs was not difficult and paralarval rearing up to around 40 days was successful. In 2007, the first juveniles were produced and the oldest juvenile reached the age of 160 days. During the initial stages, careful attention was paid to work as closely as possible with standard aquaculture procedures for live food production (mainly the use of Artemia and rotifers as live prey) and paralarval rearing techniques, in order to facilitate the step towards industrialization later on. 相似文献
104.
Transcriptional profile of pyruvate kinase and pancreatic lipase encoding mRNAs of the Pacific whiteleg shrimp Penaeus vannamei during PstDV‐1 infection
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105.
Tania Morata Silvia Falco Javier Sospedra Isabel Gadea Miguel Rodilla 《Journal of the World Aquaculture Society》2014,45(4):380-391
An environmental recovery study was carried out after the cessation of a gilt‐head seabream farm off the Mediterranean coast of Spain. Physicochemical variables of sediments, in situ benthic fluxes of oxygen and nutrients, and benthic macrofauna were measured in the farming area and at a control station. Five sampling campaigns were done, one before the closure and the others at 1, 3, 9, and 24 mo after cessation. Benthic flux of ammonium was the first variable to recover, followed by benthic fluxes of phosphate and dissolved oxygen and percentage organic matter in the sediments, which 3 mo after the cessation of farming already showed levels similar to those in the control station. Nine months after cessation, the other abiotic variables of the sediments disturbed by the activity had recovered, such as percentage coarse fraction, total phosphorus concentrations, and redox potential measurements. The recovery of the macrofauna was slower than the abiotic variables. Three months after cessation, Capitella capitata abundance had reduced drastically in the farming area, but similar specific richness levels were not observed between the two sampled zones until 2 yr after farming cessation. 相似文献
106.
Florida torreya (Torreya taxifolia Arn.) is an endangered conifer with a very limited range in the USA: two counties in Florida and one in Georgia, along the Apalachicola River. The species was once abundant in its small native range but suffered a major decline, ~99% loss, in the late 1950s to early 1960s that is thought to have been caused by a disease. Recently, a canker disease caused by Fusarium torreyae was identified as the primary cause of Florida torreya decline. Efforts to restore and preserve the species in situ and ex situ are hampered by lack of pathogen‐free planting stock, and there exists an interest in methods to verify pathogen presence in seeds and seedlings prior to collection and transport for planting. This paper presents a new species‐specific diagnostic method that enables detection of F. torreyae and may allow for conservation programmes to ensure germplasm is free of the pathogen prior to planting. 相似文献
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Lien WH Klezovitch O Fernandez TE Delrow J Vasioukhin V 《Science (New York, N.Y.)》2006,311(5767):1609-1612
During development, cells monitor and adjust their rates of accumulation to produce organs of predetermined size. We show here that central nervous system-specific deletion of the essential adherens junction gene, alphaE-catenin, causes abnormal activation of the hedgehog pathway, resulting in shortening of the cell cycle, decreased apoptosis, and cortical hyperplasia. We propose that alphaE-catenin connects cell-density-dependent adherens junctions with the developmental hedgehog pathway and that this connection may provide a negative feedback loop controlling the size of developing cerebral cortex. 相似文献