Top-down versus bottom-up forecasting strategies

Some controversy exists about the advocacy of top-down versus bottom-up forecasting strategies. Top-down forecasting refers to the process of forecasting the demand for the aggregate of items in a class and then inferring individual demands according to a percentage of the total; bottom-up refers to separately forecasting the requirements for each individual item. This paper outlines the relative advantages of each strategy and indicates the situations in which each should be preferred.     

An analytical comparison of long and short term contracts

In this paper, we describe an analytical model to determine contracting policies for a firm that purchases components from external suppliers. The model evaluates the tradeoff between the flexibility offered by short term contracts arid the fixed investments, improvement opportunities and price certainty associated with long term contracts. We show that long term contracts may not always be optimal, and discuss conditions under which short term contracts may be justified. During a recent survey of supply managers, we observed that managers often tend to participate in short term contracts, even though they claim to seek long term relationships with suppliers. Sensitivity analysis of our model provides some explanation for this observed inconsistency. We also discuss managerial implications of the analysis.     

DEFINITION AND MEASUREMENT OF MEAT TEXTURE IN MILITARY DEVELOPMENT AND PROCUREMENT

The need for improved texture evaluation methods in meat product development and procurement is discussed with emphasis on problems facing the Armed Forces. It is pointed out that inexpensive, reproducible, simple methods are needed similar to, for example, the rapid moisture analysis equipment now being used in chemical evaluation of foods.     

Effect of Delayed Cooling on the Poststorage Flesh Firmness of Apples

Decreasing the delay in proper cooling of apples before storage can decrease the softening of fruit in storage. Three apple cultivars were studied and storage delays were simulated for two growing seasons. Each cultivar showed a different softening rate in storage as a result of delays in cooling. Apple cultivars should be cooled rapidly especially those susceptible to firmness loss as a result of delays in cooling.     

MINIMIZING COLOR DEGRADATION IN BLUSH WINES1

Abstract Minimization of color degradation in blush wines was investigated. Cabernet Sauvignon wines produced with sulfur dioxide (SO₂) at different levels (0, 30, 60, and 120 mg/L) added at crush and bottling were evaluated during 12 months of storage at 16C. Addition of SO₂ at crush did not affect browning (absorbance at 420 nm) but increased red color (absorbance at 520 nm). As SO₂ levels at bottling increased, browning and red color decreased. Prefermentation treatments (hyperoxidation, nitrogen sparging, and SO₂ addition) and tannic acid addition at bottling in Cabernet Sauvignon, Delaware, and Noble blush wines stored at 16 and 37C were evaluated. Prefermentation treatments did not affect red color. Browning differences were observed in Cabernet Sauvignon but not in Delaware and Noble wines. In blush wines from all cultivars, as tannic acid levels increased, browning and red color increased. The prefermentation treatments can be used to minimize color degradation in the cultivars evaluated.     

An enzyme immunoassay for nisin

The development of an enzyme-linked immunosorbent assay (ELISA) for nisin using polyclonal antiserum is described. The method has a limit of detection of 1.9 X 10⁻² i.u. ml⁻¹ and correlates well with the bioassay. Its use in the analysis of commercial processed cheese samples is described and the results obtained compared with those from the bioassay.     

无铅钎料对波峰焊设备的影响

目前,无铅钎料应用的日益推广使得波峰焊设备问题更加突出.其中主要的问题是设备的腐蚀及材料的寿命.为此,许多设备制造商提出了不同的方案来解决此类问题.这些方案涉及范围从不对元件进行改进到使用昂贵的金替代整个钎料锅及喷嘴.本文对制造波峰焊设备"钎料元件"的所用材料进行评估.