Optimal dairy farm adjustments to increased utilization of corn distillers dried grains with solubles.

The purpose of this paper was to identify effective dairy farm management adjustments related to recent structural changes in agricultural commodity markets because of expanded biofuels production and other market factors. We developed a mathematical programming model of a representative dairy farm in New York State to estimate the effects of changes in the relative prices of important feed components on farm profitability, identify optimal adjustments for on-farm feed production, crop sales, and dairy rations that account for expanded utilization of corn distillers dried grains with solubles (DDGS), and point out potential implications of these adjustments on whole-farm nutrient planning. We mapped out an effective farm-level demand curve for DDGS by varying DDGS prices relative to other primary feed ingredients, which allowed us to compare DDGS utilization at alternative market conditions. Had the relative prices of major feed ingredients remained at their historical averages, our results suggest that there is only modest potential for feeding DDGS through supplementation in rations for dry cows and heifers as a substitute for soybean meal. However, the relatively lower DDGS prices experienced in 2008 imply an expanded optimal use of DDGS to include rations for lactating cows at 10% of the total mixed ration. Despite these expanded opportunities for DDGS at lower prices, the effects on farm net returns were modest. The most important considerations are perhaps those related to changes in the phosphorus (P) levels in the dairy waste. We showed that including moderate levels of DDGS (10%) in rations for lactating cows did not significantly increase P excretion. However, if the rations for dry cows and heifers were supplemented with DDGS, P excretion did increase, resulting in sizable increases of plant-available phosphorus applied to cropland well beyond crop nutrient requirements. Although our results show that it is economically optimal for the dairy producer to incorporate DDGS into these rations, some operations will be unable to accommodate the additional P because of existing nutrient management recommendations, soil P status, and the number of acres available for manure spreading.

Measuring the financial risks of New York dairy producers.

The financial risks of a group of New York dairy producers were measured from 1988 through 1997 and were decomposed by source of risk by two procedures. Decomposition of the variance suggested major contributors to variability in returns to New York dairy farms were variabilities in purchased feed quantities and milk production; milk price variability contributed substantially less. Similarly, decomposing the Gini measure of income dispersion indicated that milk revenues and purchased feed expenditures contributed most to farm return inequality over time. Controlling feed costs and maintaining high and stable milk production appear to be the principal approaches that dairy producers can use to control their financial risks.

Mathematics and Measurement.

In this paper we describe the role that mathematics plays in measurement science at NIST. We first survey the history behind NIST's current work in this area, starting with the NBS Math Tables project of the 1930s. We then provide examples of more recent efforts in the application of mathematics to measurement science, including the solution of ill-posed inverse problems, characterization of the accuracy of software for micromagnetic modeling, and in the development and dissemination of mathematical reference data. Finally, we comment on emerging issues in measurement science to which mathematicians will devote their energies in coming years.

[Epidemiological study of a tuberculosis case in a large manufacturing enterprise in Quebec]. / Enquête épidémiologique sur un cas de tuberculose dans une grande entreprise manufacturière québécoise.

OBJECTIVES: To determine the prevalence of tuberculosis infection related to a case of pulmonary and laryngeal tuberculosis in a workplace and to study PPD predictors. METHODS: The Mantoux skin test (PPD) was offered to all potentially infected contacts. Participants were asked to answer a questionnaire. RESULTS: Among 112 exposed employees, 92 (82.1%) were tested. At the 5 mm level, 65.2% of employees had positive tuberculin skin test (PPD). By controlling prior BCG and the degree of exposure, it showed a positive association between age and PPD (RC: 3.5; 95% CI: 1.25-10.03). When age and BCG were controlled, high exposure was statistically associated with PPD results (RC: 5.6; 95% CI: 1.25-24.68). CONCLUSION: The observed prevalence rate is probably related to the fact that the index case was very infectious and had contact in an enclosed area over a long period of time before withdrawal from work.

[Prevalence of cervical Chlamydia trachomatis infection in a female population seeking contraception counseling]. / Prévalence de l'infection cervicale à Chlamydia trachomatis dans une population féminine consultant pour contraception.

OBJECTIVES: To determine the prevalence and risk indicators of cervical infection due to Chlamydia trachomatis among female patients consulting for contraception and to evaluate an enzyme immunoassay for the detection of C. trachomatis in this setting. DESIGN: Prevalence study. Endocervical specimens were analysed by means of culture and enzyme immunoassay. C. trachomatis infection was diagnosed through culture. SETTING: A hospital family planning clinic in Trois-Rivières, Que. SUBJECTS: All 533 female patients who consulted for contraception between November 1986 and March 1988. Results of culture were available for 495 patients. MAIN OUTCOME MEASURE: Demographic, epidemiologic and clinical information was collected by means of a standard questionnaire and a gynecologic examination. MAIN RESULTS: The prevalence rate of chlamydial infection was 9% (45/495). Enzyme immunoassay detected 37 (82%) of the infections. The mean age of the patients was 19.8 years, and 98% of the infections were diagnosed in those aged 25 years or less. The variables significantly associated with C. trachomatis infection were having more than one sexual partner in the preceding year (odds ratio [OR] 2.9; 95% confidence limits [CL] 1.7 and 5.0) and having more than one partner in the preceding 3 months (OR 2.3; 95% CL 1.2 and 4.3). These two indicators would have detected 58% and 22% of the infections respectively. CONCLUSIONS: Screening for C. trachomatis infection by means of enzyme immunoassay should be proposed to all female patients aged 25 years or less consulting for contraception in our clinic. Such screening may prove to be an effective preventive measure in other similar clinical settings.

Cost-benefit analysis of thrombolytic therapy.

Thrombolysis is a new treatment for myocardial infarct patients, 162 such patients were studied: 62 received thrombolytic treatment and 100 a classical therapy. For cost-benefit analysis, all patients were followed for at least 1 year and received an identical questionnaire to assess the costs induced by this disease. At 1 year, 10% had died in the two groups. Patients who received thrombolytic treatment had a hospital stay 2 days longer, on average, but were readmitted for shorter periods (10.3 days less). Thrombolysis was more expensive (10,550 pounds vs 8998 pounds). Therefore, it is necessary to invest 150 pounds to reduce rehospitalization time by 1 day. Benefits were almost 31% greater for thrombolysis patients and the cost-benefit ratio was about 0.7. Thus the monetary benefits, initially rather negative, became positive at the end of the first year.

[The dental health of institutionalized elderly patients: from awareness to action]. / La santé dentaire des personnes âgées hébergées: de la connaissance à l'action.

Too often survey reports, studies and well advised considerations by health researchers follow one another and pile up without any real application in the day-to-day life. For example, most health professionals and health care workers and even the public in general have deplored the fact, when they read the study done by Brodeur and Simard in 1982 on the dental health of the elderly, that 72 per cent of the Quebecers of 65 years of age and older were edentulous. Yet, since this study has been published, there has been no blitz or systematic action to improve the dental health of the elderly. Unless I'm mistaken, efforts were made mostly to promote prevention among the younger generations. In the Quebec Province, the works of Dr Vallée have of course fostered some progress in the field of Geriatric Dentistry. However, it must be said again that real positive actions for the elderly patients remain few if not exceptional. Perhaps are we right when we say that seniors as a social group are somewhat neglected. Perhaps also do we consider them as a group for which there is not much left to be done... In reality, dental healthwise, is there anything better than to wish for the young generations not to have the deplorable fate of the elderly?