Monitoring leaf area of sugar beet using ERS-1 SAR data

This paper presents the results of field testing a radar model which relates leaf area index to radar backscatter for ERS-1 C-band VV polarization SAR data. Ground truth measurements of leaf area index and soil moisture content were made in selected sugar beet fields, with simultaneous acquisition of ERS-1 SAR image data. Radar backscatter coefficients were derived from the calibrated ERS-1 SAR data. The Leeuwen and Clevers expression of the water cloud model was fitted to determine the in situ relationship between radar back-scatter and leaf area index. The model can be inverted analytically to calculate leaf area index from radar backscatter. The results show considerable potential for the operational application of ERS-1 SAR data in crop monitoring.     

Rapid Direct Extraction Derivatization Method for the Determination of Acylglycerol Lipids in Selected Sample Matrices

Acylglycerol lipids as total fatty acid methylesters (FAME) were rapidly determined by direct extraction derivatization from sample matrices utilizing 0.4N methanolic sodium methoxide in hexane solution and quantitated using gas chromatography. FAME values determined by the direct extraction derivatization (DED) method and standard AOAC ether extraction saponification method were similar for all samples. The DED method was reproducible and required less than 35 min total sample preparation and analysis time compared to a minimum of 6 hr needed for the standard AOAC method. The DED method yielded FAME derivatives of acylglycerol lipids which were free from interfering compounds when analyzed by gas chromatography. Identity and purity of isolated FAME were positively confirmed by mass spectrometry by comparison with authentic standards.     

Challenge Studies with Selected Pathogenic Bacteria on Freshly Peeled Hamlin Orange

The survival and growth of Salmonella spp., Escherichia coli O157:H7, Listeria monocytogenes , and Staphylococcus aureus on peeled Hamlin orange were examined. Fruits were peeled by infusing the peel with water to assist hand removal. The peeled oranges had an average pH of 6.0–6.5 at the surface and 3.8 in the juice. After surface inoculation, peeled fruits were incubated for up to 14 days. Growth was observed with all tested pathogens only at the abusive storage temperature (24°C). Refrigeration (4 or 8°C) effectively inhibited the growth of all pathogens and caused population reduction of Salmonella spp. and S. aureus.     

ABILITY OF COLICIN V TO CONTROL ESCHERICHIA COLI O157:H7 IN GROUND BEEF

Culture counts of Escherichia coli O157:H7 showed that colicin V caused rapid death in buffered (pH 7) cell suspensions at 30C. A decrease in optical density of cell suspensions indicated that colicin V lysed cells. Decreased optical densities were proportional to increased colicin V concentrations. Colicin V was also effective in killing E. coli O157:H7 in ground beef at 4, 20 and 30C. Initial rates of killing were directly proportional to temperature.     

Characterization of the calcification of cardiac valve bioprostheses by environmental scanning electron microscopy and vibrational spectroscopy

Bioprosthetic heart valve tissue and associated calcification were studied in their natural state, using environmental scanning electron microscopy (ESEM). Energy dispersive X‐ray micro‐analysis, X‐ray diffraction, Fourier‐transform infrared and Raman spectroscopy were used to characterize the various calcific deposits observed with ESEM. The major elements present in calcified valves were also analyzed by inductively coupled plasma–optical emission spectroscopy. To better understand the precursor formation of the calcific deposits, results from the elemental analyses were statistically correlated. ESEM revealed the presence of four broad types of calcium phosphate crystal morphology. In addition, two main patterns of organization of calcific deposits were observed associated with the collagen fibres. Energy dispersive X‐ray micro‐analysis identified the crystals observed by ESEM as salts containing mainly calcium and phosphate with ratios from 1.340 (possibly octacalcium phosphate, which has a Ca/P ratio of 1.336) to 2.045 (possibly hydroxyapatite with incorporation of carbonate and metal ion contaminants, such as silicon and magnesium, in the crystal lattice). Raman and fourier‐transform infrared spectroscopy also identified the presence of carbonate and the analyses showed spectral features very similar to a crystalline hydroxyapatite spectrum, also refuting the presence of precursor phases such as β‐tricalcium phosphate, octacalcium phosphate and dicalcium phosphate dihydrate. The results of this study raised the possibility of the presence of precursor phases associated with the early stages of calcification.     

Cognitive activities in OO development

The cognitive activities performed by systems designers during systems development include problem understanding, problem decomposition and solution specification. One aspect of object-oriented (OO) approaches to system design that appeals to many adopting organizations is the purported naturalness, i.e. the consistency of OO approaches with these cognitive activities of problem solving. Essentially, OO aims to abstract components of the problem of system development to a high level that parallels problem solving in the world the system represents. In other words, knowing how a problem is solved in the real world informs one about how the OO system solves the problem. Thus, the OO development process and the resulting OO model are believed to be consistent with innate cognitive activities and consistent with the problem/real world, respectively. A cognitive mapping method was used to ask graduate students experienced with OO techniques about their perceptions of what is complex (difficult to understand) about OO systems. Their responses include a set of concepts, categories of similar concepts and cognitive maps that reveal what they believe is difficult about using OO techniques. Evaluating these perceptions in terms of the cognitive activities of system design reveals problem decomposition was perceived as the activity that caused the most difficulties related to learning OO techniques. Problem understanding was the goal of the participants, while the solution activity ranked lower in importance but contained many issues essential to systems development and influenced problem understanding.