Produção de matéria seca e absorção de nutrientes pelo milho em razão da saturação por bases e da adubação potássica Dry matter yield and nutrient uptake in corn plants as a function of potassic fertilization and of basis soil saturation

O trabalho foi conduzido em condições de casa de vegetação, com o objetivo de avaliar a resposta do milho à adubação potássica e à saturação do solo por bases, na produção de matéria seca e na absorção de nutrientes. O delineamento experimental foi inteiramente casualizado, com quatro repetições, em esquema fatorial 3x2x4, constituindo-se de três solos (Areia Quartzosa, Latossolo Vermelho-Escuro e Latossolo Roxo), dois valores de saturação por bases (40% e 70 %) e quatro teores de K no solo (0,5, 1,5, 3,0 e 6,0 mmol c dm-3). Para a calagem, foi utilizada mistura de carbonato de cálcio + carbonato de magnésio (PRNT = 103,3 %) na proporção de 4:1. A adubação básica constou de 200 mg kg-1 de N, 200 mg kg-1 de P e 5 mg kg-1 de Zn por vaso de 30 L, sendo o N parcelado em 2,48 g (83,7 mg kg-1) na semeadura e o restante em duas coberturas aos 25 e 40 dias após a emergência das plântulas (DAE). As doses de K utilizadas foram de 0, 3,62, 7,24 e 14,48 g de KCl por vaso. A semeadura foi realizada em 4/3/97, utilizando-se o milho cv. Zêneca 8392, mantendo-se uma planta/vaso durante 60 DAE. O K proporciona ganhos de matéria seca até teores de 1,5 mmol c dm-3 no solo. O aumento dos teores de K no solo resultam em queda na concentração de Ca e Mg na matéria seca do milho. A elevação da saturação por bases e respectivo aumento dos teores de Ca e Mg no solo reduzem a absorção de K pelo milho.<br>The purpose of this research was to study dry matter yield and nutrients uptake by corn plants as a function of potassic fertilization and of soil basis saturation. An experiment was conducted under greenhouse conditions, using an early single hybrid corn Zêneca 8392 grown in 30 L pots, tested with three types of soil (Quartzpsamment and two alic Dark-Red Latosol - Haplorthox), with two levels of basis saturation (40 and 70 %) and four levels of potassium content (0.5, 1.5, 3.0 and 6.0 mmol c dm-3). A completely random design with four replications was utilized. The basis saturation treatments were calibrated by liming the soils with a mixture of 4:1 of calcium and magnesium carbonate, according to soil type. K content in the soil was established by applying 0, 3.62, 7.24 and 14.48 g of KCl per 30 L pot. P (200 mg kg-1) and Zn (5 mg kg-1) were applied to all treatments at sowing time. N was applied at sowing time (83.7 mg kg-1) as well as at top dressing, 25 and 40 days after seedling emergence, totalizing 200 mg kg-1. Sixty days after seedling emergence the dry matter weight and N, P, K, Ca and Mg content of the leaves and stems were determined. The dry matter yield was increased by K concentrations in the soil up to 1.5 mmol c dm-3. The increase in soil K levels allowed decrease on the Ca and Mg concentrations in corn dry matter. The increase of basis saturation and soil Ca and Mg levels decrease corn plant K uptake

The playfulness of eBay and the implications for business as a game-maker

The purpose of this article is to theorize and to illustrate how eBay as a game may both support and undermine playful consumption. In reaching that aim, we argue that business models such as eBay that operate in an experiential economy supplying new games for restless consumers to play may find it hard to sustain their initial success. As internal and external forces transform “playful” behaviors into “professional” ones and as imaginative and autotelic play is rationalized such that its purpose becomes extrinsic, consumer boredom may follow. Conceptually, we make a case for an appraisal of consumption as playful activity, borrowing key concepts from Caillois's sociology derived from play to guide our analysis of recent developments in eBay's business model as well as to flesh out an explanation as to how eBay engages playful consumption. We conclude by commenting on society's preferred play forms for businesses and for consumer cultur

Body mass index and complications following major gastrointestinal surgery: A prospective, international cohort study and meta-analysis

Aim Previous studies reported conflicting evidence on the effects of obesity on outcomes after gastrointestinal surgery. The aims of this study were to explore the relationship of obesity with major postoperative complications in an international cohort and to present a metaanalysis of all available prospective data. Methods This prospective, multicentre study included adults undergoing both elective and emergency gastrointestinal resection, reversal of stoma or formation of stoma. The primary end-point was 30-day major complications (Clavien–Dindo Grades III–V). A systematic search was undertaken for studies assessing the relationship between obesity and major complications after gastrointestinal surgery. Individual patient meta-analysis was used to analyse pooled results. Results This study included 2519 patients across 127 centres, of whom 560 (22.2%) were obese. Unadjusted major complication rates were lower in obese vs normal weight patients (13.0% vs 16.2%, respectively), but this did not reach statistical significance (P = 0.863) on multivariate analysis for patients having surgery for either malignant or benign conditions. Individual patient meta-analysis demonstrated that obese patients undergoing surgery formalignancy were at increased risk of major complications (OR 2.10, 95% CI 1.49–2.96, P < 0.001), whereas obese patients undergoing surgery for benign indications were at decreased risk (OR 0.59, 95% CI 0.46–0.75, P < 0.001) compared to normal weight patients. Conclusions In our international data, obesity was not found to be associated with major complications following gastrointestinal surgery. Meta-analysis of available prospective data made a novel finding of obesity being associated with different outcomes depending on whether patients were undergoing surgery for benign or malignant disease