Peru: integration, sectoral specialization and synchronization with international gross domestic product cycles

Includes bibliography

Enzyme effects on extruded diets for dogs with soybean meal as a substitute for poultry by-product meal

The effects of exogenous enzymes supplementation on kibble diets for dogs formulated with soybean meal (SBM) as a substitute for poultry by-product meal (PM) was investigated on nutrient digestibility, fermentation products formation, post-prandial urea response and selected faecal bacteria counts. Two kibble diets with similar compositions were used in two trials: PM-based diet (28.9% of PM; soybean hulls as a fibre source) and SBM-based diet (29.9% of SBM). In experiment 1, the SBM diet was divided into three diets: SBM-0, without enzyme addition; SBM-1, covered after extrusion with 7500U protease/kg and 45U cellulase/kg; and SBM-2, covered with 15000U protease/kg and 90U cellulase/kg. In experiment 2, the SBM diet was divided into three diets: SBM-0; SBM-1, covered with 140U protease/kg; 8U cellulase/kg, 800U pectinase/kg, 60U phytase/kg, 40U betaglucanase/kg and 20U xylanase/kg; and SMB-2, covered with 700U protease/kg, 40U cellulase/kg, 4000U pectinase/kg, 300U phytase/kg, 200U betaglucanase/kg and 100U xylanase/kg. Each experiment followed a block design with six dogs per diet. Data were submitted to analysis of variance and means compared by orthogonal and polynomial contrasts (p<0.05). In both experiments, nutrients and energy digestibility did not differ between diets (p>0.05). SBM consumption resulted in increased faecal moisture and production (p<0.05), without effect on faecal score. Higher concentration of propionate, acetate and lactate, and lower ammonia and pH were found in the faeces of dogs fed SBM (p<0.05). Higher post-prandial urea was verified in dogs fed SBM (p<0.05). In experiment 2, the addition of enzymes increased faecal concentration of propionate, acetate and total short-chain fatty acid (p<0.05) and tended to reduce post-prandial urea concentration (p=0.06). Although with similar digestibility, SBM shows a worse utilization of absorbed amino acids than the PM. Soybean oligosaccharides can beneficially change gut fermentation product formation. Enzymes can increase the gut fermentation activity and improve the SBM proteic value. © 2013 Blackwell Verlag GmbH.

When less is better: Insights from the product mix dilemma from the Theory of Constraints perspective

Perhaps due to its origins in a production scheduling software called Optimised Production Technology (OPT), plus the idea of focusing on system constraints, many believe that the Theory of Constraints (TOC) has a vocation for optimal solutions. Those who assess TOC according to this perspective indicate that it guarantees an optimal solution only in certain circumstances. In opposition to this view and founded on a numeric example of a production mix problem, this paper shows, by means of TOC assumptions, why the TOC should not be compared to methods intended to seek optimal or the best solutions, but rather sufficiently good solutions, possible in non-deterministic environments. Moreover, we extend the range of relevant literature on product mix decision by introducing a heuristic based on the uniquely identified work that aims at achieving feasible solutions according to the TOC point of view. The heuristic proposed is tested on 100 production mix problems and the results are compared with the responses obtained with the use of Integer Linear Programming. The results show that the heuristic gives good results on average, but performance falls sharply in some situations. © 2013 Copyright Taylor and Francis Group, LLC.

Product mix: The approach of throughput per day

Defining product mix is very important for organisations because it determines how productive resources are allocated among various operations. However, it is often defined subjectively. The methods commonly used for this definition are Integer Linear Programming and heuristics based in Theory of Constraints, which use maximum throughput as a performance measure. Although this measure provides maximum throughput to specific problem, it does not consider aspects of time, as days, utilised to make the throughput. Taking this into account, the aim of this paper is to present a throughput per day approach to define product mix, as well as to propose a constructive heuristic to help in this process. The results show that the proposed heuristic obtained satisfactory approximation when compared to the optimum values obtained by enumeration. © 2013 Copyright Taylor and Francis Group, LLC.

The use of NaOCl in combination with CHX produces cytotoxic product

Objectives: The combination of sodium hypochlorite (NaOCl) and chlorhexidine (CHX) yields a precipitate potentially toxic (PPT). The aim of this study was to evaluate the tissue response to implanted polyethylene tubes filled with PPT-soaked fibrin sponge. Methods: Forty rats received four polyethylene tubes each; each tube was filled with fibrin sponge soaked by 2.5 % NaOCl, 2.0 % CHX, PPT (2.5 % NaOCl plus 2.0 % CHX), or not soaked (control). The observation time points were 7, 15, 30, 60, and 90 days. At each time point, eight animals were killed, and the tubes and surrounding tissues were removed, fixed, and prepared for light microscopic analysis by performing glycol methacrylate embedding, serial cutting into 3-μm sections, and hematoxylin-eosin staining. Qualitative and quantitative evaluations of the reactions were performed. Results were statistically analyzed by Kruskal-Wallis test (p < 0.05). Results: All chemical solutions caused moderate reactions at 7 days. On day 30, PPT group was more cytotoxic than the control group and the CHX group (p < 0.05). On days 15 and 60, PPT group was more cytotoxic than the control group (p < 0.05). On day 90, there was no statistically significant difference between the different groups. Conclusion: PPT is more cytotoxic than NaOCl and CHX alone, particularly in the short term. Clinical significance: Protocols which suggest the use of CHX and NaOCl must be revised because this mixture produces cytotoxic product. © 2013 Springer-Verlag Berlin Heidelberg.

The historical relationship between energy-consumption and gross national product in the United States

Includes bibliography