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Many previous empirical studies on the productivity of pesticides suggest that pesticides are under-utilized in agriculture despite the general held believe that these inputs are substantially over-utilized. This paper uses data envelopment analysis (DEA) to calculate non-parametric measures of the value of the marginal product of pesticides. Furthermore, the effect of pesticides on the value of the marginal product of productive inputs is investigated in order to analyze technical interdependence between pesticides and productive inputs. Results suggest, in general, substantial under-utilization of pesticides, which is consistent with earlier findings of parametric specifications.JEL Classification: C6, Q0, Q1

Nonparametric dynamic measures of production efficiency are developed in the context of an adjustment-cost technology and intertemporal cost minimization. Bounds on each efficiency measure are derived for each firm using a nonparametric revealed preference approach. Long-run efficiency measures indicate the relative efficiency of both variable and dynamic factors while short-run measures of efficiency indicate whether variable inputs are employed efficiently in the production process. The efficiency measures are temporal in nature by describing the degree of efficiency of the firm at a particular point along its adjustment path. The empirical implementation is illustrated for a balanced panel of Pennsylvania dairy operators during 1986&-1992. Copyright 2007, Oxford University Press.

During 1995, we added gold sodium thiosulfate and potassium dicyanoaurate to the patch test standard series. Our purpose was to compare the reactivity of the gold salts, to determine the frequency of contact allergy to gold in our country, to compare our results with those of the Malmö group and, finally to try to clarify the clinical relevance 2853 patients were routinely tested and 168 patients answered a questionnaire similar to that used by the Malmö group. Contact allergy to gold was found in 23 patients, all women: 22 to gold sodium thiosulfate (0.78%), only 1 to potassium dicyanoaurate and 2 to both salts. All reactors had their ears pierced and were exposed to gold jewelery (mainly earrings). Simultaneous allergies to nickel and cobalt were statistically significant in patients with positive patch tests to gold sodium thiosulfate. Atopy was no more common among these patients.

We present the case of a 72-year-old woman observed for dermatitis on the legs followed by apperance of erythema on the eyelids. She had a past history of peripheral venous insufficiency and had been using self home-made Aloe vera juice over the legs for relief from pain. Patch tests showed positive reactions to the leaf of Aloe, the macerated Aloe jelly, and nickel sulfate. Although most manufacturers process Aloe products avoiding its irritant extracts, and probably as a consequence reports of allergic reactions are rare, one must remember that the growing popularity on the use of Aloe products may stimulate its use 'as is' by the patients. Furthermore, it is important to specifically ask patients about the use of these products, because they consider it as innocuous and thus would not spontaneously provide such information. Case reportA 72-year-old woman was observed for a 3-month history of pruriginous erythema of the legs, followed by intense itching, erythema, and desquamation of the eyelids (Figs 1 and 2). Shortly before, she had started applying self home-made Aloe vera leaf juice over the legs for the treatment of chronic peripheral venous insufficiency. There was no history of atopy or other relevant medical condition.

In this article, a new method to estimate the ridge parameter, based on the ridge trace and an analytical method borrowed from maximum entropy, is presented. The performance of the new estimator is illustrated through a Monte Carlo simulation study and an empirical application to the well-known Portland cement data set.

No abstract

Atopic dermatitis (AD) is a common disorder and appears to be on the increase, especially among children. It was thought at first to be a manifestation of immediate hypersensitivity, but it is now known that delayed hypersensitivity also plays an important role. Sensitivity to mite antigens is found in 20% to 60% of patients when immediate hypersensitivity is evaluated by the detection of specific IgE antibodies and prick tests, and in 30% to 50% of patients when delayed hypersensitivity is studied by patch testing. A prospective randomized study was carried out in the pediatric dermatology clinic on a sample of 51 children under 15 years of age. A prevalence of immediate and delayed hypersensitivity to mites, like that described for other populations, was found. It was further found that there was a positive association, not described in the literature, between the younger age groups and delayed hypersensitivity to mite antigens, while the opposite was true for immediate hypersensitivity. We believe that patch tests with airborne allergens, specifically mites, should be part of the protocol for assessing children with AD, particularly in the younger age groups.