Non-destructive measurement techniques for taper equation development: a study case in the Spanish Northern Iberian Range

In recent years, the technology for measuring the diameter and height of standing trees has improved significantly. These enhancements allow estimation of the volume of standing trees using stem taper equations, which traditionally have been constructed with data from felled trees, in an accurate and economically feasible way. A non-destructive method was evaluated with data from 38 pines and was validated with data from another 38 pines, both in the Northern Iberian Range (Spain). The electronic dendrometer Criterion RD1000 (Laser Technology Inc.) and the laser hypsometer TruPulse (Laser Technology Inc.) were used due to their accuracy and interoperability. The methodology was valid (unbiased and precise) measuring from a distance similar to the height of the tree. In this distance, statistical criteria and plots based on the residuals showed no clear advantage in volume estimation with models fitted with data from destructive methods against models fitted with data from the proposed non-destructive technique. This methodology can be considered useful for individual volume estimation and for developing taper equations.     

Buffelgrass (Pennisetum ciliare) land conversion and productivity in the plains of Sonora, Mexico

Bufflelgrass (Pennisetum ciliare syn. Cenchrus ciliaris) is an African grass that has been widely introduced in subtropical arid regions of the world to improve rangelands for cattle production. However, it can have a negative effect on the diversity of native plant communities. Buffelgrass was introduced to Sonora, Mexico in the 1970s as a means to bolster the cattle industry. “Desmonte,” the process by which native desert vegetation is removed in preparation for buffelgrass seeding, alters the land surface such that buffelgrass plots are easily detectable from aerial and Landsat satellite images. We estimated the extent of conversion to buffelgrass in a 1,850,000 ha area centered on Hermosillo, from MSS and TM images from 1973, 1983, 1990 and 2000. We then compared the relative above-ground productivity of buffelgrass to native vegetation using Normalized Difference Vegetation Index values (NDVI) from Landsat and Moderate Resolution Imaging Spectrometer (MODIS) satellite sensor systems. Buffelgrass pastures have increased from just 7700 ha in 1973 to over 140,000 ha in 2000. Buffelgrass pastures now cover 8% of the land surface in the study area. Buffelgrass pastures have lower net primary productivity, estimated by MODIS NDVI values, than unconverted desert land. The desmonte process removes trees and shrubs, while the buffelgrass plantings are often sparse, leading to an apparent net loss in net primary production from land conversion. We recommend that the desmonte process be discontinued until its efficacy and safety for native ecosystems can be established, and that a comprehensive plan for preserving biodiversity while accomodating economic development be established for this region of the Sonoran Desert in Mexico.     

Temporal variation in breeding,foraging and bird sanctuary visitation by a Southern African Population of great white pelicans Pelecanus onocratalus

Temporal variation in visitation, breeding and foraging during 1977–1978 at a breeding site and a proclaimed bird sanctuary are described for a southern African population of great white pelicans Pelecanus onocratalus. Foraging activity and sanctuary visitation were at low levels during the austral winter (May–August). The pelicans bred at only one site, Dassen Island (33° 25t?, 18° 12′ E), in three major waves in spring and summer (September–March), coinciding with periods of high visitation and foraging activity at Rondevlei Bird Sanctuary (34° 04′S, 18° 30′ E), an important foraging and roosting site within the range of the population. Temporal variation in these aspects of pelican biology is influenced by the fluctuating availability of suitable foraging habitat and fish prey. Water depth and rainfall, those environmental factors which appear to affect the availability of foraging habitat and fish prey, were correlated strongly negatively with measures of pelican foraging activity and sanctuary visitation during 1977–1978. They were also negatively correlated with measures of sanctuary visitation calculated for a 22-year period. Therefore, these factors may have influenced patterns of foraging and visitation of this great white pelican population over the long term.     

Interpreting vegetation indices

Remotely sensed spectral vegetation indices are widely used and have benefited numerous disciplines interested in the assessment of biomass, water use, plant stress, plant health and crop production. The successful use of these indices requires knowledge of the units of the input variables used to form the indices, and an understanding of the manner in which the external environment and the architectural aspects of a vegetation canopy influence and alter the computed index values. Although vegetation indices were developed to extract the plant signal only, the soil background, moisture condition, solar zenith angle, view angle, as well as the atmosphere, alter the index values in complex ways. The nature of these problems are explored both in an empirical and in a theoretical sense, and suggestions are offered for the effective use and interpretation of vegetation indices.     

Antioxidant activity of diterpenes and polyphenols from Ophryosporus heptanthus

The antioxidant activity of 14 compounds (1-14) isolated from the ether and butanolic extracts of the aerial parts of Ophryosporus heptanthus has been assayed using a beta-carotene bleaching method and the DPPH technique. Compounds 1 and 13 showed the most potent antioxidant activity. Their structures have been established by spectroscopic techniques (mainly NMR). Compounds 7 and 12 are new natural products, and their structures have been confirmed by chemical synthesis.     

Pork Meat Quality of Preto Alentejano and Commercial Largewhite Landrace Cross

This work aimed to evaluate the physical-chemical characteristics of pork from a local breed （Portuguese black pork called Preto Alentejano） and a commercial breed. Sixteen animals were used, 4 females and 4 males from each breed. Animals had 80-100 kg of live weight. The longissimus muscle between the 5th thoracic vertebra and the 10th lumbar vertebra was used in the analysis. Samples were analysed for protein, fat, pigments, ashes, dry mater, water-holding capacity, and texture. Results of fat and pigments contents indicate signiifcant （P〈0.05 and P〈0.01） differences for all treatments. For protein, ashes, dry mater, water-holding capacity and texture, no signiifcant differences were found for sex. In the analysis of fatty acids composition, ten were detected, being the main ones C16：0, C18：0, C16：1, C18：1, C18：2. There was a predominance of monounsaturated fatty acids （MUFA）, followed by saturated （SFA） and polyunsaturated （PUFA）. Differences were signiifcant for sex （P〈0.01） and breed （P〈0.01）. Preto Alentejano breed and females presented the higher percentages of SFA （P〈0.01） and MUFA （P〈0.001） fatty acids. Differences between breeds might be due to breed production system and feed differences.     

Silicon‐induced cadmium resistance in rice (Oryza sativa)

Silicon (Si)‐induced cadmium (Cd) tolerance in rice (Oryza sativa L.) was investigated by analyzing Cd uptake, growth, and physiological parameters. Silicon treatments (0.0, 0.2, or 0.6 mM) were added to 6 d–old seedlings, and Cd treatments (0.0 or 5.0 μM) were added to 20 d–old seedlings. Parameters determined included: maximum net CO₂ assimilation (A_max), stomatal conductance (g_smax), and transpiration (E_max) rates at varying intercellular CO₂ concentrations (C_i). Also measured were chlorophyll fluorescence, growth, and Cd‐uptake parameters. Results showed a Si‐induced inhibition of Cd uptake. However, 0.2 mM or 0.6 mM Si treatment concentrations did not differentially inhibit Cd uptake or differentially alleviate Cd‐induced growth inhibition, despite a significant increase in tissue Si concentration due to 0.6 mM Si treatment compared to 0.2 mM Si treatment. Additionally, photosynthesis and chlorophyll‐fluorescence analysis showed that treatment with Cd significantly inhibited photosynthetic efficiency. Interestingly, the addition of 0.2 mM Si, more so than the addition of 0.6 mM Si, significantly alleviated the inhibitory effects of Cd toxicity on photosynthesis and chlorophyll‐fluorescence parameters. Our results suggest that 0.2 mM Si could be close to an optimum Si‐dose requirement for the alleviation of toxicity symptoms mediated by moderate (5 μM) Cd exposure.     

Influence of processing conditions on acrylamide content in black ripe olives

The presence of acrylamide was investigated in different presentations of commercial black ripe olives, a well-known sterilized alkali-treated product. The analysis was performed by gas chromatography-mass spectrometry (GC-MS) after bromination of acrylamide, using (13C3)acrylamide as internal standard. In-house validation data for commercial ripe olives showed good precision and accuracy of the method, with repeatability below 3% and recoveries between 94 and 105%. Acrylamide was detected in all samples, but its concentration varied significantly from 176 to 1578 microg/kg of pulp. The effects of different processing conditions (two preservation methods and three darkening methods), cultivar (Hojiblanca or Manzanilla), and presentation form (pitted or sliced olives) on acrylamide content were evaluated in experiments performed in an olive-processing plant. All canned samples were sterilized at 121 degrees C for 30 min. Statistical analysis of the data indicated that the effects of darkening method and olive cultivar were the most pronounced. Acrylamide contents did not significantly differ after 6 months of storage. The small amounts of free amino acids and reducing sugars found in olives before sterilization did not significantly correlate with the acrylamide formed.     

Nutraceutical,Physicochemical, and Sensory Properties of Blue Corn polvorones,a Traditional Flour-Based Confectionery

Blue corn is an anthocyanin-rich material that can be used in the preparation of baking products. The aim of this work was to evaluate the physicochemical, nutraceutical, and sensory properties of polvorones (a traditional flour-based confectionery) made with whole blue-corn flour. All samples showed similar bromatological composition, but polvorones from whole blue-corn flour had a higher phenolics (837.1 mg gallic acid/kg) and anthocyanins (373.0 mg cyanidin-3-glucoside/kg) content, which exerted an influence on their higher antioxidant activity compared with wheat flour-based laboratory and commercial samples. The transformation of raw blue-corn flour into polvorones produced the degradation of some acylated anthocyanins into non-acylated forms. The substitution of wheat flour with whole blue-corn flour enhanced overall acceptability, as well as the color and flavor of polvorones. Our findings demonstrated that it is possible to use whole blue corn in the formulation of polvorones with more health beneficial properties and better consumer acceptability than refined wheat products.     

Modeling nitrogen mineralization at surface and deep layers of sandy soils

We evaluated potential soil nitrogen mineralization of 46 sandy fields of the Pampas for determining the contribution of deep layers to mineralization and modeling its trend in depth as a possible tool for improving current existing mineralization models based on surface data. Mineralization, total and mineral nitrogen decreased with depth. A potential model fitted well to these variables (R² = 0.95–0.99), but mineralization showed a more stratified profile. Consequently, the fraction of total nitrogen mineralized decreased with depth despite soils had constant texture across the profile. Potential mineralization to 1 m depth could be estimated using data from the 0–0.2-m soil layer and the average curvature of the potential model (R² = 0.60) or linear regression methods (R² = 0.71). Another estimation of potential mineralization could be performed by developing a pedotransfer function which used as predictors total nitrogen and depth (R² = 0.62), without the need of laboratory incubations. Our results showed that for sandy soils, deep nitrogen mineralization account for 40% of soil mineralization and can be assessed using surface data or the total nitrogen content of the soils. Because surface soil mineralization and whole profile mineralization were highly correlated, it is improbable that field mineralization modeling may be improved using deep data in these soils.