信令网的核心--下一代信令转接点

本文在讨论了下一代信令转接点在满足传统信令网络功能的基础上，着重介绍了下一代的信令转接点上实现的号码携带、灵活路由等新业务，并如何实现传统STP面向下一代网络的平滑过渡。     

ROUGH KNOWLEDGE DISCOVERY FOR NUCLEAR SAFETY

Large amounts of data are generated in the investigating and maintaining of nuclear energy. Making full use of this data to gain useful insights into, for example, safety issues, presents a tremendous challenge. It is well-known that rough set theory can be applied successfully to rough classification and knowledge discovery. Our work is concerned with finding methods for using rough sets to identify classes in datasets, finding dependencies in relations and discovering rules which are hidden in databases. We believe that these methods can be used to understand and control aspects of nuclear energy generation. So in this paper we illustrate the use of our rough discovery methods by means of a running example using data on nuclear safety from the Belgian Nuclear Reactor 1 (BR1).     

Some further evidence for a counter-example in singular optimal control problems

This paper first completes an investigation started by Bell and Turpin (1981). It is shown that for a general second-order system with a drift term and for which parameter values are q = 1, m = 2, McDanell's conjecture is correct. Following this, a statement is given of all necessary conditions that must be satisfied at a junction in order for a counter-example to the conjecture to exist. These conditions prove to be consistent, indicating that it is worth continuing the search for such a counterexample     

The Influence of Improved Physical Property Data on Calculated Heat Transfer Coefficients

Heat transfer coefficients calculated from accepted correlations, but using physical properties derived from different sources, are compared with experimentally determined local heat transfer coefficients. In all cases, consistent, accurate property data yield more accurate estimates of the heat transfer coefficients.     

Glass Transition Explanation for the Effect of Polyhydroxy Compounds on Protein Denaturation in Dehydrated Solids

Dehydrated proteins are frequently subjected to thermal stress in the presence of other components. The effect such substances may have upon protein structure, and therefore function, has not been fully investigated. Thus, the effect of added polyhydroxy components on the denaturation of lyophilized β-lactoglobulin, ovalbumin, and ribonuclease, as determined by differential scanning calorimetry, was evaluated. The denaturation temperature, T_m, of the globular proteins decreased in the dry state after the addition of sucrose, sorbitol, or glycerol. The thermal stability (based on T_m) of the dehydrated proteins appeared to correlate with the glass transition temperature (T_g) of the polyhydroxy component, which was assumed to be related to the T_g of the mixture. The lower the T_g of the component, the greater was the degree of protein destabilization. Thus, glass transition data may be used to predict the effect that a component would have on denaturation of dehydrated proteins at elevated temperatures.     

BOTULINAL TOXIN PRODUCTION IN VACUUM AND CARBON DIOXIDE PACKAGED MEAT DURING CHILLED STORAGE AT 2 AND 4C

This study was undertaken to determine if carbon dioxide packaging of meat afforded a food safety advantage over vacuum packaging with respect to botulinal toxin production during chilled storage. A cocktail of washed spores from five toxigenic clostridial strains – four reference Clostridium botulinum strains [types A, B (2 strains) and E] and a C. butyricum type E strain – was inoculated onto lamb chumps. Of these strains, two were psychrotolerant. The inoculated chumps were individually carbon dioxide packaged and duplicate packs were placed into storage at 10, 8, 6, 4 and 2C. All storage regimens included a weekly defrost cycle when meat surface temperatures increased by up to 6 to 7C during a 2 to 2.5 h period. After 84 days storage, packs were assessed for the presence of botulinal toxin using the mouse bioassay procedure. All packs contained botulinal toxin. To compare toxin production in vacuum and carbon dioxide packs at chill temperatures, the challenge trials were repeated for 4 and 2C storage. Packs were examined at regular intervals for toxin presence. Both pack types contained toxin after 21 and 48 days storage at 4 and 2C, respectively. In the unlikely, but not impossible, event that raw meat would be contaminated with psychrotolerant toxincapable clostridial spores, product safety, with respect to botulinal toxin presence after prolonged chilled storage, requires storage temperatures to be maintained below 2C for both vacuum and carbon dioxide packaged product.     

Factors influencing the determination of nisin in meat products

Recovery of nisin from minced meat and meat emulsions was poor and variable. The rate of recovery was little affected by the presence of NaCl and/or NaNO₂, particle size, or the meat to extractant (0.02N HCl) ratio, but was significantly affected by the fat content of the meat. For nisin added at 100 iu/g, recoveries at the optimal meat to extractant ratio, 10% wt/wt suspension, ranged from 26% at 3% fat to 76% at 83% fat. At addition levels of 200 iu/g and greater, nisin recovery efficiency was reduced.     

Implications of nitrogen nutrition for grapes, fermentation and wine

This review discusses the impacts of nitrogen addition in the vineyard and winery, and establishes the effects that nitrogen has on grape berry and wine composition and the sensory attributes of wine. Nitrogen is the most abundant soil‐derived macronutrient in a grapevine, and plays a major role in many of the biological functions and processes of both grapevine and fermentative microorganisms. Manipulation of grapevine nitrogen nutrition has the potential to influence quality components in the grape and, ultimately, the wine. In addition, fermentation kinetics and formation of flavour‐active metabolites are also affected by the nitrogen status of the must, which can be further manipulated by addition of nitrogen in the winery. The only consistent effect of nitrogen application in the vineyard on grape berry quality components is an increase in the concentration of the major nitrogenous compounds, such as total nitrogen, total amino acids, arginine, proline and ammonium, and consequently yeast‐assimilable nitrogen (YAN). Both the form and amount of YAN have significant implications for wine quality. Low must YAN leads to low yeast populations and poor fermentation vigour, increased risk of sluggish/stuck/slow fermentations, increased production of undesirable thiols (e.g. hydrogen sulfide) and higher alcohols, and low production of esters and long chain volatile fatty acids. High must YAN leads to increased biomass and higher maximum heat output due to greater fermentation vigour, and increased formation of ethyl acetate, acetic acid and volatile acidity. Increased concentrations of haze‐causing proteins, urea and ethyl carbamate and biogenic amines are also associated with high YAN musts. The risk of microbial instability, potential taint from Botrytis‐infected fruit and possibly atypical ageing character is also increased. Intermediate must YAN favours the best balance between desirable and undesirable chemical and sensory wine attributes. ‘Macro tuning’, of berry nitrogen status can be achieved in the vineyard, given genetic constraints, but the final ‘micro tuning’ can be more readily achieved in the winery by the use of nitrogen supplements, such as diammonium phosphate (DAP) and the choice of fermentation conditions. This point highlights the need to monitor nitrogen not only in the vineyard but also in the must immediately before fermentation, so that appropriate additions can be made when required. Overall, optimisation of vineyard and fermentation nitrogen can contribute to quality factors in wine and hence affect its value. However, a better understanding of the effect of nitrogen on grape secondary metabolites and different types of nitrogen sources on yeast flavour metabolism and wine sensory properties is still required.