Pectolytic Enzymes in Sweet Bell Peppers (Capsicum annuum L.)

Low levels of polygalacturonase (PG) and pectinesterase (PE) activities were quantitated in sweet bell peppers at four stages of maturity based on surface ground color (dark green, light green, turning, and red). The PG activity increased during pepper ripening and was maximal at the turning stage while the PE activity declined during ripening and was maximal at the light green stage. Pepper texture measurements were found to decline concomitantly with the increase in PG activity. Pepper PG showed pH optimum between 4.8 to 5.0 and increased temperature stability with advanced ripening. Compared to tomatoes, pepper PG activity was 116- to 164-fold lower and pepper PE activity was 429- to 1900-fold lower than the corresponding tomato enzymes.     

SOLUBILITY AND EMULSIFYING PROPERTIES OF BETACASEIN MODIFIED ENZYMATICALLY BY TRYPSIN

Beta A1-casein was treated with TPCK-trypsin to give 3.2, 5.0, 5.8 and 7.4% hydrolysis of the peptide bonds. By sodium dodecyl sulfate-polyacrylamide gel electrophoresis the resulting peptides had apparent molecular weights in the range 8,000–4,000. Size-exclusion chromatography of hydrolyzed samples showed four major peaks near 15,000, 5,500, 3,500 and 2,500 molecular weights, representing 17, 15, 7 and 14% of the material, respectively, after 3.2% hydrolysis and 9, 6, 14 and 52% of the material, respectively, after 7.4% hydrolysis. Between the extremes 3.2% and 7.4% hydrolysis, a peak near 8,500 molecular weight was present until 5.8% hydrolysis then disappeared after 7.4% hydrolysis to be replaced by a peak near 12,000 molecular weight. Peptides recovered from reversed-phase high performance liquid chromatography were analyzed by determination of their amino acid composition and identified in the sequence of β-casein. After trypsin treatment, the solubility of β-casein hydrolysates was largely increased at pH 4.0–7.5. The emulsifying activity of the hydrolysates was higher than that of β-casein in the range of pH 1.5–3.5 and 6.5–10.0, but all the emulsions obtained with trypsin-treated β-casein were less stable than those obtained with original β-casein.     

Correlation between Rm and Standard Affinity of Some Anionic Azo Dyes on Cellulose

Results on affinity measurements and paper chromatography of some anionic azo dyes, obtained by diazotization of 4-aminobenzophenone, 2(4′-amino-benzoyl)thiophene, 4′-aminobenzanilide, 2-thiophene-carboxanilide-4′-amino, trans-4-aminostilbene and trans-2(4′-aminostyryl)thiophene and coupling with naphthionic acid, Nevile-Winther's acid, R acid, Hacid and chromotropic acid, have been reported. A linear relationship between the R_m value of the dyes and their standard affinity of dyeing has been observed for dyes with the same coupling component.     

Band-aid or Panacea? The Role of Private Rental Support Programs in Addressing Access Problems in the Australian Housing Market

Australia has a significant private rental market with over a quarter of households renting their home from a private landlord. Many of these households are on low incomes and receive assistance from private rental support programs provided by each Australian state and territory. In spite of these large numbers, little is known about the effectiveness of policy initiatives to assist low-income private renters. Limited knowledge of the private rental support programs stands in stark contrast to the detailed research on programs established to address homelessness and problems within the public housing sector. This paper addresses this lacuna by reporting on the suite of initiatives currently funded by state governments to assist low-income households (for example, bond loans and rental deposits, advice and help with removal expenses). Based on a comprehensive study of Private Rental Support Programs (PRSPs) commissioned by the Australian Housing and Urban Research Institute, it is argued that though policies to assist vulnerable tenants are acknowledged as a success by practitioners and clients, their effectiveness as a policy instrument is undermined by wider structural changes in the housing market. The paper concludes that the stress faced by many vulnerable households is likely to intensify over the coming years thereby compounding the pressure on state Housing Authorities to provide more comprehensive packages of support that extend beyond just a ‘one-off’ form of assistance.     

APPLICATION OF FREQUENCY DIVERSITY FOR DIMENSIONING A Ka-BAND SATELLITE SYSTEM

The growth of the demand for telecommunication services is going to saturate the frequency bands usually used (C or K_u). For this reason the K_a-band is much considered and is going to be highly used. To meet the requirements of a more developed market a satellite system in K_a-band with European coverage and better performance than those of common VSATs, especially in terms of capacity and of link availability, is proposed and characterized. The negative effect due to the high rain attenuation, that represents the main impairment using K_a-band, can be mitigated using one or more fade countermeasures. Frequency diversity, which well suites the characteristics of the proposed systems, has been analysed and characterized in detail using a model developed at Politecnico di Milano. Its performances are shown as a function of different system parameters such as total number of stations, number of assisted stations, link availability and statistical dependence among stations. The aim of the paper is to introduce a design methodology and to show the advantages obtainable using frequency diversity for a K_a-band system with higher performances than common VSATs. The advantages achieved for rain margins are shown and system design parameters are then compared with those of an uncompensated system. Using this type of countermeasure, the dimensioning of the whole system (both payload and earth-station) is proved to be much less severe.     

GOING ONLINE WITHOUT EASY ACCESS: A TALE OF THREE CITIES

ABSTRACT: Building on a national study that showed that concentrated poverty matters for the “digital divide,” this research compares the influence of the neighborhood‐level context in three cities that vary in racial composition and income. We use a 2005 random digit‐dialed survey of respondents in Northeast Ohio communities, and find unexpectedly that residents in areas of concentrated poverty demonstrate efforts to go online despite lacking home or work access. We analyze the results using regression models that include contextual “buffers” that create a unique geography for each respondent within a half‐kilometer radius. Respondents who live in areas with a high percentage of African Americans or college graduates are more likely to go online even if they lack convenient Internet access, although the percentage of college graduates has a greater effect. At the neighborhood level, race and education influence the context for technology use.     

ASCETA: AN EXPERT SYSTEM FOR PASSIVE NETWORK SYNTHESIS

An expert system for passive network synthesis and filter design, developed in an object-oriented environment, is presented. It has been implemented using a shell written in the language SMALL2ALK/V and is highly interactive. It has been conceived and developed mainly for educational purposes, and its implementation has demonstrated the suitability of the object-oriented approach and of the SMALLTALK environment for this kind of problem.     

Probabilistic assessment of small disturbance stability in multimachine power systems

In planning electric power systems, it is always necessary to assess whether small-disturbance (SD) instability phenomena occur at prefixed system operating conditions. This analysis can become very difficult when the problem data are uncertain. In such cases the use of deterministic approaches is inadequate and the application of probabilistic analysis techniques is the most feasible alternative. This paper presents a new and practical probabilistic approach for the assessment of SD stability in multimachine power systems taking into account the uncertainties associated with bus load forecasting and treating loads as random uncorrelated variables with normal distributions. This approach proves suitable for determining the risk of SD instability for each expected system operating condition and for systematically individualizing all factors that can affect the probability of SD instability in large power systems. A numerical example illustrates the capability of the proposed technique.