Multi-spectral classification of snow using NOAA AVHRR imagery

Abstract

Problems of accurate discrimination between snow and cloud, together with the detection of the snow pack boundary, have handicapped the use of satellite data in operational snow-cover mapping systems. A technique, involving an unsupervised clustering procedure, is described which allows the removal of cloud areas using NOAA-9 Advanced Very High Resolution Radiometer (AVHRR) channel-1, channel-3 and channel-4 data in conditions of recent snow lie and a difference channel (channel-2 —channel-1 with channel-3 and channel-4) during periods of advanced snow melt. Accurate delineation of snow extent is provided by the techniques if these specified snow conditions are taken into account. A method for the identification of areas of marginal snow melt is also presented, based on comparisons with Landsat Thematic Mapper data. The classifications also enable the determination of snow areas influenced by cloud shadows and conifer forest in addition to separating areas of differing snow depth and percentage cover.     

Behavior of Aflatoxin during the Manufacture, Ripening and Storage of Manchego-type Cheese

The behavior of aflatoxins B₁, B₂, G₁, G₂, and M₁ was investigated during manufacture, ripening, refrigeration, and frozen storage of Manchego-type cheese. More aflatoxins (per weight or volume) occurred in curd than in whey, although total quantity was greater in whey. Aflatoxins B₁ B₂, and M₁ remained stable during ripening, but G₁ and G₂ levels increased. Concentration of B₁, B₂, and M₁ decreased after 15 and 30 days refrigeration storage, but after 60 days 100% recovery occurred in the inner portion and only 60% in the outer. Concentrations of G₁ and G₂ also decreased during the first 30 days, but on day 60 an increase was observed, 200% in the inner and 120% in the outer portions. Aflatoxins were stable after 90 days in frozen storage.     

SUBCHRONIC TOXICITY STUDY OF EASTERN BLACK NIGHTSHADE (SOLANUM PTYCANTHUM) BERRIES IN SPRAGUE-DAWLEY RATS

Species of the Solanum nigrum complex, including eastern black nightshade (S. ptycanthum Dun.), are common nuisance plants, and their berries often contaminate agricultural commodities. Black nightshade plants and their fruits contain solanaceous glycoalkaloids, but little information is available regarding their toxicity in vivo. Male and female rats were fed diets containing 0, 1, 5 or 25% (w/w) eastern black nightshade berries (BNB) for 13 weeks. BNB had no effect upon clinical appearance and behavior, body weight, food and water consumption, serum chemical profiles or organ weights. Gross or microscopic lesions related to BNB were not found. Anemia was present in high-dose males after six weeks and in mid-dose males, high-dose males and high-dose females after 13 weeks. Erythrocyte counts, hemoglobin concentrations and hematocrits of these groups were significantly decreased and averaged 81–93% of their respective control values. Erythrocyte counts, hemoglobin concentration and hematocrits of males fed 1% BNB, females fed 1% BNB and females fed 5% BNB averaged 94–97% of the control values after 13 weeks. These findings indicate that ingestion of low to moderate amounts of S. ptycanthum berries does not pose a significant health risk, although anemia may be a potential consequence of prolonged exposure to highly contaminated foodstuffs .     

An assessment of radiance in Landsat TM middle and thermal infrared wavebands for the detection of tropical forest regeneration

It has been postulated that tropical forests regenerating after deforestation constitute an unmeasured terrestrial sink of atmospheric carbon, and that the strength of this sink is a function of regeneration stage. Such regeneration stages can be characterized by biophysical properties, such as leaf and wood biomass, which influence the radiance emitted and/or reflected from the forest canopy. Remotely sensed data can therefore be used to estimate these biophysical properties and thereby determine the forest regenerative stage. Studies conducted on temperate forests have related biophysical properties successfully with red and near-infrared radiance, particularly within the Normalized Difference Vegetation Index (NDVI). However, only weak correlations have generally been observed for tropical forests and it is suggested here that the relationship between forest biophysical properties and middle and thermal infrared radiance may be stronger than that between those properties and visible and near-infrared radiance.

An assessment of Landsat Thematic Mapper (TM) data revealed that radiance acquired in middle and thermal infrared wavebands contained significant information for the detection of regeneration stages in Amazonian tropical forests. It was demonstrated that tropical forest regeneration stages were most separable using middle infrared and thermal infrared wavebands and that the correlation with regeneration stage was stronger with middle infrared, thermal infrared or combinations of these wavebands than they were with visible, near infrared or combinations of these wavebands. For example, correlation coefficients increased from — 0·26 (insignificant at 95 per cent confidence level) when using the NDVI, to up to 0·93 (significant at 99 per cent confidence level) for a vegetation index containing data acquired in the middle and thermal infrared wavebands. These results point to the value of using data acquired in middle and thermal infrared wavebands for the study of tropical forests.     

Immersion Chilling and Freezing: Phase Change and Mass Transfer in Model Food

The influence of immersion chilling and freezing process variables (temperature, concentration, agitation) on phase change and salt gain, was studied on a gelatin gel dipped into a NaCl solution, with particular emphasis on unsteady state (first hour). Under freezing conditions, water loss was <2 g/100g initial gel and salt gain remained low (<1 g/100g initial gel). Salt penetration was hindered by formation of an ice barrier, which was favored by high concentration and low temperature. Under chilling conditions, salt gain was higher (up to 2 g/100g initial gel), and was enhanced when temperature or concentration increased.     

Visualization of volume data in confocal microscopy: comparison and improvements of volume rendering methods

Confocal microscopes routinely produce three-dimensional data sets. The visualization of these digital volumes is currently performed by one surface rendering or volume rendering approach. In this paper, we describe improvements developed in the field of volume rendering. We focused on three methods: parallelepiped face mapping: the rotation-projection method (with or without stereoscopy, with different matters and transparencies); the voxel ray-tracing method. We compared the possibilities of these different algorithms, in terms of quality of rendering, of computation load and as an essential aid to study the 3D organization of biological specimens.     

ION EXCHANGE KINETICS OF DL-LYSINE MONOHYDROCHLORIDE ON AMBERLITE IRA-420

ABSTRACT

The ion exchange kinetics of DL-lysine monohydrochloride on Amberlite IRA-420 have been studied. Ionic diffusivity of hydroxyl anion, which is supposed to be equal to the interdiffusion coefficient, has been evaluated by fitting experimental kinetic data to a theoretical model based on the continuity equation of the CI" anion in solution filling the pores of the resin. Because of changes of both viscosity with ionic concentration and co-ion behavior in solution at high concentrations, a variation of ionic diffusivity of hydroxyl anion has been observed. In order to predict the dynamic behavior of fixed beds a simple mathematical model including both equilibrium isotherm and ionic diffusivity of hydroxyl anion has been developed. Likewise, resin regeneration using NaOH solutions has been investigated. The results show the feasibility of the procedure of purification and regeneration and they have been used to design a plant for the treatment of 50 Tm/yr of DL-lysine monohydrochloride.     

CHEMICAL MACHINING FROM ANOTHER VIEWPOINT*

This paper uses the statistical tool of analysis of variance to look at the recommended operating values for chemical machining.

The results obtained agree in general with those published by The Chem-Mill Division of Turco Products Inc., except that there was an indication of some deterioration of surface finish when using sodium aluminate in the solution.

The results obtained should not be used in general, but only applied where the material and method are comparable to the one used in the study.     

New results on relationships between multipoint Padé approximation and stability preserving methods in model reduction

Three well-known stability preserving methods of reduction are shown to be special forms of the multipoint pade approximation. Two of the methods—the modified forms of the Schwarz approximation and the stability equation method—are consequently shown to be closely related. Previously observed properties of the methods are explained by treating them as multipoint approximants, and the significance of using expansion points on the imaginary axis is shown to be central to stability preservation.