Water content measurement in black spruce and aspen sapwood with benchtop and portable magnetic resonance devices

Abstract

In this study, water content in black spruce (Picea mariana Mill.) and aspen (Populus tremuloides Michx.) sapwood samples was investigated with time-domain magnetic resonance (MR). Time-domain MR measurements easily distinguish water in different environments in wood according to the spin-spin relaxation time and provide quantitative information on water content. The MR techniques employed can distinguish and quantify the individual signal components. Both black spruce and aspen have two signal components at moisture contents above the fiber saturation point. These two signal components correspond to motionally restricted water, often referred to as bound water, and unrestricted, or free water. Bound water content is constant above 40% moisture content. No signal from free water was detected at or below 20% moisture content in either species. We also demonstrate the use of a recently developed portable unilateral magnet that can be employed as a powerful tool in the study and measurement of water content in wood.     

Introduction: Working Forests in the Tropics: Policy and Market Impacts on Conservation and Management

Abstract

Tropical forests are very rich in biological diversity and form an important economic and ecological resource. This biodiversity is of great value for communities living in or near these forests as a ready source of subsistence and cash income, and for the world at large as a source of tropical timber and non-timber products and a repository of genetic and chemical information. However, this biological complexity is diminishing rapidly. We analyze the main human (anthropogenic) actions causing loss of tropical forest biodiversity along with the strategies of management for forest biodiversity. Not only is the biophysical component important in management for biodiversity, but the active participation and support of local people, national governments, and the international community as a whole are essential to effective and sustainable development of tropical forests. This development strategy ensures that socioeconomic and environmental benefits are provided for present and future generations.     

Cost of distributing oral raccoon-variant rabies vaccine in Ohio: 1997-2000

OBJECTIVE: Analysis of the cost of 8 distributions of oral rabies vaccine (ORV) with strains known to infect raccoons in Ohio between 1997 and 2000. DESIGN: Original study. PROCEDURE: Fishmeal bait containing ORV was distributed on foot, by vehicle, and by helicopter and fixed-wing aircraft. The cost of personnel, vehicles, and helicopter and aircraft use and other associated expenses were obtained from field records and interviews with personnel and agencies involved in the ORV program. RESULTS: Each bait distribution lasted approximately 1 week. Areas baited ranged from 1,701 km2 to 6,497 km2. Density varied for each distribution, with means of 79 baits/km2 for ground baiting and 93 baits/km2 for aerial baiting. Typically, 72 people participated in the ground portion of each distribution and 32 in the aerial portion. The cost of ground baiting (mean +/- SD, 19.24 dollars/km2 +/- 6.35 dollars/km2) was consistently less than that for air baiting (mean +/- SD, 24.71 dollars/km2 +/- 4.65 dollars/kml) for each distribution. The total cost of distribution varied from 30,568 dollars to 145,842 dollars (mean, 96,791 dollars), and bait cost varied from 150,714 dollars to 1,029,423 dollars (mean, 543,839 dollars). The total cost of ORV distributions ranged from 102 dollars/km2 to 261 dollars/km2 (mean, 153 dollars/km2). CONCLUSIONS: In the United States, rabies strains that infect raccoons have been responsible for the largest increase in rabies in animals in the past 3 decades. Use of ORV is a promising new tool that can be used to control rabies in raccoons. Documenting the estimated cost of implementing an ORV program may lead to more efficient use of resources to control and limit the spread of rabies. In addition, accurately measured distribution costs can be used to perform an economic cost-benefit analysis for an ORV program.     

Cellular Impact of Metal Trace Elements in Terricolous Lichen Diploschistes muscorum (Scop.) R. Sant. – Identification of Oxidative Stress Biomarkers

The purpose of this research is to present toxic effects of some heavy metals (cadmium, lead and zinc) on lichen physiology. In the North of France, those metals are concentrated for example in industrial polluted soils near metallurgic plants and waste dumps. Our investigations were conducted on Diploschistes muscorum (Scop.) R. Sant, a terricolous lichen growing on previously quoted soils as well as on non-contaminated ones. Different stress parameters were investigated as potassium leakage – which is related to the loss of membrane integrity – and oxidative stress through following parameters: malondialdehyde (MDA), glutathione (GSH) and superoxide dismutase (SOD). It seems, therefore, that heavy metals induce oxidative stress in this lichen, in which we found membrane damage and enhancement of SOD activity and GSH concentrations. With regard to very high concentrations of Cd, Pb and Zn, a resistance involving antioxidant mechanisms limits the expected damage. Those mechanisms involve GSH, SOD as well as secondary metabolites, which have this resistance property. This study is a first step of investigation to use – in the future– physiological parameters as tool for environment assessment.     

Antibody class switching mediated by yeast endonuclease-generated DNA breaks

Antibody class switching in activated B cells uses class switch recombination (CSR), which joins activation-induced cytidine deaminase (AID)-dependent double-strand breaks (DSBs) within two large immunoglobulin heavy chain (IgH) locus switch (S) regions that lie up to 200 kilobases apart. To test postulated roles of S regions and AID in CSR, we generated mutant B cells in which donor Smu and accepter Sgamma1 regions were replaced with yeast I-SceI endonuclease sites. We found that site-specific I-SceI DSBs mediate recombinational IgH locus class switching from IgM to IgG1 without S regions or AID. We propose that CSR evolved to exploit a general DNA repair process that promotes joining of widely separated DSBs within a chromosome.     

Shifting cultivation on the tidal floodplains of Amazônia: impacts on soil nutrient status

Studies of the impact of traditional agroforestry practices on soil nutrient status in the Amazon Basin have largely been limited to upland sites, many of which are oligotrophic. However, rural population density in Amazonia is highest on the floodplains of the major rivers and shifting cultivation has been practiced on the floodplains for millennia. We established a slash-and-burn cultivation plot and an untreated forest plot in tidal floodplain successional forest in the Islands of Abaetetuba, Pará, Brazil, and sampled soils (0–10 cm) during four phases of the agroforest cycle (n = 9 in each plot for each sampling period): (1) prior to clearing, (2) following burning, (3) harvest one (rice at four months), and (4) harvest two (sugar cane at 15 months). During the course of this pilot experiment, background temporal variability in SOC, total N and available mineral nutrient pools (P, K, Ca, Mg) exceeded treatment effects, suggesting that soil nutrient pools in this environment are well-buffered against the effects of shifting cultivation. These results contrast markedly with those reported for Amazonian upland sites where nutrient pulses and declines associated with the agroforest cycle have been demonstrated and may restrict the potential for low-input, continuous cultivation. Physical limitations imposed by flooding and fluvial erosion, rather than nutrient constraints, restrict the potential of agricultural intensification in the tidal floodplains. This revised version was published online in June 2006 with corrections to the Cover Date.     

Using near-infrared hyperspectral images on subalpine fir board. Part 1: Moisture content estimation

Abstract

In this study, moisture content (MC) images of subalpine fir (abies lasiocarpa Hook) boards were derived from near-infrared hyperspectral images in the 947–1637 nm range. One hundred and seven cubic samples with the size of 4 cm were prepared from 14 boards. All samples were dried to various MCs during several steps until being completely dried. Hyperspectral images and weight measurements were acquired over each sample at each drying step. The samples have MC ranging from 1% to 137% (dry basis). The images were first calibrated into reflectance. Then, bad pixels were found and replaced by a corrected value using a median filter. A modified version of the boxplot method was used to find abnormal spectra that were then removed. The remaining spectra were converted into absorbance spectra. They were then split into a calibration and a validation data-set according to the boards they were extracted from to build and validate a partial least squares (PLS) regression model between the near-infrared absorbance spectra and the measured MCs. The PLS model was applied first to the sample images, then to the whole board images in order to produce 2D images of MC.     

Acute oxalate intoxication associated to ingestion of eshnan (<Emphasis Type="Italic">Seidlitzia rosmarinus</Emphasis>) in sheep

An outbreak of acute oxalate intoxication in a sheep flock was associated to Seidlitzia rosmarinus (Chenopodiaceae) with a mortality rate of about 19%. Affected sheep showed marked azotemia and hypocalcemia. Post-mortem findings included congestion and hemorrhage in visceral organs, ruminitis frequently associated with precipitation of birefringent calcium oxalate crystals, and acute nephrosis with numerous birefringent calcium oxalate crystals in renal tubules. This is the first report of oxalate poisoning due to ingestion of S. rosmarinus in sheep.