企业生死选择：变则通，不变则完

"我真的可以改变!"谁都会这样说,可悲的是,大多数企业并没有这样去做.一项调查显示,在困难面前,作出改变与不改变的比例为1:9.在全球市场竞争不断加剧的今天,我们急需打破现有的不适用的游戏规则.     

SellPoint为在线零售商提供视频导购

SAN RAMON,CALIF.-随着越来越多的消费者为了节省燃油费用而选择在家购物,电子商务的视频导购,比如说SellPoint的可定制在线产品视频就被各个在线购物网站大量采用。     

Reduction of the pesticides oxamyl and methomyl by FeII: effect of pH and inorganic ligands

This work examines the effect that pH and selected inorganic ligands have on the kinetics of reactions between FeII and two structurally related oxime carbamate pesticides, oxamyl and methomyl. In anoxic solutions containing FeII, these compounds degrade by parallel elimination and reduction pathways. Rates of FeII-independent carbamate elimination (EIcb mechanism) are proportional to [OH-], increasing 10-fold for each unit increase in pH. In homogeneous solution, rates of carbamate reduction by 0.5 mM FeII are relatively constant at pH <7, but increase dramatically between pH 7 and pH 8.3. At pH >8.3, Fe(OH)2(s) precipitation occurs, and carbamates react with both solution-phase and solid-phase FeII. Carbamate reduction by FeII is not significantly affected by the presence of chloride, bromide, nitrate, perchlorate, and sulfate. In contrast, increased rates of carbamate reduction are observed in solutions containing fluoride, carbonate, and phosphate. Kinetic measurements are interpreted in terms of changing FeII speciation according to the expression kred = [FeII]sigmaikialphai, where k(red) is the pseudo-first-order rate constant for carbamate reduction, [FeII] is the total FeII concentration, and ki and alphai are the second-order rate constant and fractional concentration of each FeII species, respectively. It follows that the overall kinetics of carbamate reduction is a function of the identity and concentration of individual FeII species present in solution as well as the inherent reactivity of each species with carbamates. The magnitude of ki is related to the standard one-electron reduction potential (E(H) degrees) of the corresponding FeIII/FeII redox couple.     

2,5-diketopiperazines in food and beverages: Taste and bioactivity

2,5-Diketopiperazines (2,5-DKPs) have been found to occur in a wide range of food and beverages, and display an array of chemesthetic effects (bitter, astringent, metallic, and umami) that can contribute to the taste of a variety of foods. These smallest cyclic peptides also occur as natural products and have been found to display a variety of bioactivities from antibacterial, antifungal, to anthroprotective effects and have the potential to be used in the development of new functional foods. An overview of the synthesis of these small chiral molecules and their molecular properties is presented. The occurrence, taste, and bioactivity of all simple naturally occurring 2,5-DKPs to date have been reviewed and those found in food from yeasts, fungi, and bacteria that have been used in food preparation or contamination, as well as metabolites of sweeteners and antibiotics added to food are also reviewed.     

Effect of milk centrifugation and incorporation of high-heat-treated centrifugate on the composition,texture, and ripening characteristics of Maasdam cheese

This study investigated the effect of centrifugation (9,000 × g, 50°C, flow rate = 1,000 L/h), as well as the incorporation of high-heat-treated (HHT) centrifugate into cheese milk on the composition, texture, and ripening characteristics of Maasdam cheese. Neither centrifugation nor incorporation of HHT centrifugate into cheese milk had a pronounced effect on the compositional parameters of any experimental cheeses, except for moisture and moisture in nonfat substance (MNFS) levels. Incorporation of HHT centrifugate at a rate of 6 to 10% of the total milk weight into centrifuged milk increased the level of denatured whey protein in the cheese milk and also increased the level of MNFS in the resultant cheese compared with cheeses made from centrifuged milk and control cheeses; moreover, cheese made from centrifuged milk had ～3% higher moisture content on average than control cheeses. Centrifugation of cheese milk reduced the somatic cell count by ～95% relative to the somatic cell count in raw milk. Neither centrifugation nor incorporation of HHT centrifugate into cheese milk had a significant effect on age-related changes in pH, lactate content, and levels of primary and secondary proteolysis. However, the value for hardness was significantly lower for cheeses made from milk containing HHT centrifugate than for other experimental cheese types. Overall, centrifugation appeared to have little effect on composition, texture, and ripening characteristics of Maasdam cheese. However, care should be taken when incorporating HHT centrifugate into cheese milk, because such practices can influence the level of moisture, MNFS, and texture (particularly hardness) of resultant cheeses. Such differences may have the potential to influence subsequent eye development characteristic, although no definitive trends were observed in the present study and further research on this is recommended.     

New directions in migration research

This paper takes several surveys of the literature concerning migration research as its starting point and directs the reader toward a number of potentially fruitful lines for future research. Major sections include one on modeling migrant choice in which the pros and cons of using gross versus net migration measures are discussed. A second introduces and discusses the concept of a spatial choice set, which has the potential to be implemented with laboratory experimental techniques. The third involves a wide-ranging discussion of new directions in modeling the interrelationships between employment and migration.This paper was prepared in connection with the Western Regional Science Association's President's Panel, Molokai, Hawaii, February 1990.     

Hydrogen storage and demand to increase wind power onto electricity distribution networks

An optimal power flow (OPF) methodology is developed to investigate the provision of a demand hydrogen as a means to maximise wind power generation in relation to a constrained electricity network. The use of excess wind energy to generate hydrogen for use as a transport fuel is investigated. Hydrogen demand is included in the objective function of the OPF, and a techno-economic analysis is presented. We conclude that using this method to generate hydrogen increases the utilisation of wind energy and allows for a hydrogen demand to be met at or near to the point of use. The OPF algorithm that has been developed optimises the amount of wind energy utilised, as well as minimising the amount of hydrogen demand not met. The cost at which the hydrogen is produced was found to be dependent on the operating methodology, component capital investment costs, level of hydrogen demand, and storage constraint.