Rendimento de grãos de milho cultivado após aveia-preta em resposta a adubação nitrogenada e regime hídrico

O rendimento de grãos de milho é influenciado pela disponibilidade de nitrogênio (N) no solo durante o ciclo de desenvolvimento da planta. O objetivo deste trabalho foi avaliar os efeitos da adubação nitrogenada em pré-semeadura e do regime hídrico no rendimento de grãos e nos componentes de rendimento em cultivo de milho sob semeadura direta após aveia-preta. O experimento foi conduzido em Eldorado do Sul, RS, no ano agrícola de 1998/99. Os tratamentos constaram da aplicação de um nível de irrigação adequado às exigências da cultura, e outro, com excesso hídrico; e de sete sistemas de aplicação de N em milho: 0-30-150, 150-30-0, 75-30-75, 0-30-60, 60-30-0, 30-30-30 e 0-30-0, correspondendo, respectivamente, às quantidades de N (kg ha-1) aplicadas em pré-semeadura (no momento de dessecação da aveia-preta), na semeadura e em cobertura do milho. Com a antecipação da aplicação de N da cobertura para a época de pré-semeadura, o rendimento de grãos de milho foi menor em relação ao obtido com a aplicação na época convencional, principalmente sob alta disponibilidade hídrica e com elevada dose de adubação nitrogenada. O componente mais associado ao rendimento de grãos de milho foi o número de grãos por espiga.

Experimental investigation of the initial regime in fingering electrodeposition: Dispersion relation and velocity measurements.

Recently a fingering morphology, resembling the hydrodynamic Saffman-Taylor instability, was identified in the quasi-two-dimensional electrodeposition of copper. We present here measurements of the dispersion relation of the growing front. The instability is accompanied by gravity-driven convection rolls at the electrodes, which are examined using particle image velocimetry. While at the anode the theory presented by Chazalviel et al. [J. Electroanal. Chem. 407, 61 (1996)] describes the convection roll, the flow field at the cathode is more complicated because of the growing deposit. In particular, the analysis of the orientation of the velocity vectors reveals some lag of the development of the convection roll compared to the finger envelope.

Influence of silvicultural regime on wood structure characteristics and mechanical properties of clear wood in Pinus sylvestris

Abstract

Reconstruction of the join time-delay Doppler-scale reflectivity density in the wide-band regime. A frame theory based approach

The inverse scattering problem concerning the determination of the joint time-delayDoppler-scale reflectivity density characterizing continuous target environments is addressed by recourse to the generalized frame theory. A reconstruction formula,involving the echoes of a frame of outgoing signals and its corresponding reciprocalframe, is developed. A ‘‘realistic’’ situation with respect to the transmission ofa finite number of signals is further considered. In such a case, our reconstruction formula is shown to yield the orthogonal projection of the reflectivity density onto a subspace generated by the transmitted signals.

NDA waveform estimation in the low-SNR regime

This correspondence addresses the problem of nondata-aidedwaveform estimation for digital communications. Based on the unconditionalmaximum likelihood criterion, the main contribution of this correspondenceis the derivation of a closed-form solution to the waveform estimationproblem in the low signal-to-noise ratio regime. The proposed estimationmethod is based on the second-order statistics of the received signaland a clear link is established between maximum likelihood estimation andcorrelation matching techniques. Compression with the signal-subspace isalso proposed to improve the robustness against the noise and to mitigatethe impact of abnormals or outliers.

Dynamics of Appropriability - Finding a Balance between Efficiency and Strength in the Appropriability Regime

Building and sustaining competitive advantage through the creation of market imperfections is challenging in a constantly changing business environment - particularly since the sources of such advantages are increasingly knowledge-based. Facilitated by improved networks and communication, knowledge spills over to competitors more easily than before,thus creating an appropriability problem: the inability of an innovating firm to utilize its innovations commercially. Consequently, as the importance of intellectual assets increases, their protection also calls for new approaches. Companies have various means of protection at their disposal, and by taking advantage of them they can make intangibles more non-transferable and prevent, or at leastdelay, imitation of their most crucial intellectual assets. However, creating barriers against imitation has another side to it, and the transfer of knowledge in situations requiring knowledge sharing may be unintentionally obstructed. Theaim of this thesis is to increase understanding of how firms can balance knowledge protection and sharing so as to benefit most from their knowledge assets. Thus, knowledge protection is approached through an examination of the appropriability regime of a firm, i.e., the combination of available and effective means ofprotecting innovations, their profitability, and the increased rents due to R&D. A further aim is to provide a broader understanding of the formation and structure of the appropriability regime. The study consists of two parts. The first part introduces the research topic and the overall results of the study, and the second part consists of six complementary research publications covering various appropriability issues. The thesis contributes to the existing literature in several ways. Although there is a wide range of prior research on appropriability issues, a lot of it is restricted either to the study of individual appropriability mechanisms, or to comparing certain features of them. These approaches are combined, and the relevant theoretical concepts are clarified and developed. In addition, the thesis provides empirical evidence of the formation of the appropriability regime, which is consequently presented as an adaptive process. Thus, a framework is provided that better corresponds to the complex reality of the current business environment.

Composição da produção e qualidade da uva em videira cultivada sob dupla poda e regime microclimático estacional constrastante

Em São Paulo, destaca-se a viticultura como atividade familiar de caráter artesanal. Nas bacias de maior concentração atual da vitivinicultura, ocorre um período chuvoso que se estende de novembro a fevereiro, que alcança grande parte das variedades da região em fase de crescimento e maturação da baga, o que afeta negativamente a qualidade da uva e do vinho artesanal, na maioria das safras. Por outro lado, nas mesmas regiões, ocorre um período mais favorável, que é o outono/inverno com potencial de soma térmica adequado ao crescimento da videira e com incidência de um longo período de baixa pluviometria, entre os meses de abril e outubro. Um experimento foi conduzido em Jundiaí (SP), região de média altitude (700 m), com variedades de uvas híbridas e fina, no qual, objetivou-se estudar os impactos ecofisiológicos do cultivo da videira conduzida sob dupla poda, forçando-se a condução das plantas por quatro estações de cultivo sequenciais de verão e inverno; analisaram-se aspectos da ecofiosologia da cultura e a composição quali-quantitativa do rendimento. Os resultados mostram que a estação de outono-inverno apresenta condições mais favoráveis à maturação fenólica das bagas, com chuvas mais bem distribuídas e desconcentradas no período do estabelecimento do fruto à colheita. A uva colhida na estação de outono-inverno apresentou maiores índices de pigmentação fenólica em relação à estação de cultivo tradicional, sendo que o controle do nível de reservas da planta revelou influência da dupla poda sequencial sobre esta variável, o que inspira práticas de manejo específicas para este tipo de exploração da videira.

The empirical assessment of agency accountability: A regime approach and an application to the German Bundesnetzagentur

Regulation has in many cases been delegated to independent agencies, which has led to the question of how democratic accountability of these agencies is ensured. There are few empirical approaches to agency accountability. We offer such an approach, resting upon three propositions. First, we scrutinize agency accountability both de jure (accountability is ensured by formal rights of accountability 'fora' to receive information and impose consequences) and de facto (the capability of fora to use these rights depends on resources and decision costs that affect the credibility of their sanctioning capacity). Second, accountability must be evaluated separately at political, operational and managerial levels. And third, at each level accountability is enacted by a system of several (partially) interdependent fora, forming together an accountability regime. The proposed framework is applied to the case of the German Bundesnetzagentur's accountability regime, which shows its suitability for empirical purposes. Regulatory agencies are often considered as independent, yet accountable. This article provides a realistic framework for the study of accountability 'regimes' in which they are embedded. It emphasizes the need to identify the various actors (accountability fora) to which agencies are formally accountable (parliamentary committees, auditing bodies, courts, and so on) and to consider possible relationships between them. It argues that formal accountability 'on paper', as defined in official documents, does not fully account for de facto accountability, which depends on the resources possessed by the fora (mainly information-processing and decision-making capacities) and the credibility of their sanctioning capacities. The article applies this framework to the German Bundesnetzagentur.

Predicting the future effectiveness of protected areas for bird conservation in Mediterranean ecosystems under climate change and novel fire regime scenarios

AimGlobal environmental changes challenge traditional conservation approaches based on the selection of static protected areas due to their limited ability to deal with the dynamic nature of driving forces relevant to biodiversity. The Natura 2000 network (N2000) constitutes a major milestone in biodiversity conservation in Europe, but the degree to which this static network will be able to reach its long-term conservation objectives raises concern. We assessed the changes in the effectiveness of N2000 in a Mediterranean ecosystem between 2000 and 2050 under different combinations of climate and land cover change scenarios. LocationCatalonia, Spain. MethodsPotential distribution changes of several terrestrial bird species of conservation interest included in the European Union's Birds Directive were predicted within an ensemble-forecasting framework that hierarchically integrated climate change and land cover change scenarios. Land cover changes were simulated using a spatially explicit fire-succession model that integrates fire management strategies and vegetation encroachment after the abandonment of cultivated areas as the main drivers of landscape dynamics in Mediterranean ecosystems. ResultsOur results suggest that the amount of suitable habitats for the target species will strongly decrease both inside and outside N2000. However, the effectiveness of N2000 is expected to increase in the next decades because the amount of suitable habitats is predicted to decrease less inside than outside this network. Main conclusionsSuch predictions shed light on the key role that the current N2000may play in the near future and emphasize the need for an integrative conservation perspective wherein agricultural, forest and fire management policies should be considered to effectively preserve key habitats for threatened birds in fire-prone, highly dynamic Mediterranean ecosystems. Results also show the importance of considering landscape dynamics and the synergies between different driving forces when assessing the long-term effectiveness of protected areas for biodiversity conservation.

Estudos da eletrodeposição de metais em regime de subtensão

This work reviews recent studies of underpotential deposition (UPD) of several metals on Pt and Au substrates performed in the Grupo de Materiais Eletroquímicos e Métodos Eletroanalíticos (IQSC -- USP, São Carlos). The UPD Cu, Cd and Pb on Pt were analysed in terms of their influence in the oxygen evolution reaction. Partial blockage of surface active sites, promoted by Pb ad-atoms, resulted in a change from water to hydrogen peroxide as the final product. The Ag UPD on Pt and Au substrates was also discussed in this work. A detailed model of charge calculation for Ag monolayer was developed and confirmed by the rotating ring-disk data. The partial charge transfer in UPD studies was analysed in the Cd/Pt and Cd/Au systems and a value of 0.5 was found for the adsorption electrovalence of Cd ad-ions. The Sn/Pt UPD systems were studied from the point of view of the valences of metallic ions in solution. The deposition from Sn(IV) generates a full monolayer with a maximum occupation of approximately 40% of the surface active sites (340 µC cm-2) plus 105 µC cm-2 of Hads (half monolayer). Changing the metallic ion for Sn(II), it was possible to deposit a full monolayer (210 µC cm-2) without any detectable Hads. Finally, the effect of anions was discussed in the Zn/Pt and Zn/Au systems. Here, the hydrogen evolution reaction (her) and the hydrogen adsorption/desorption were used in order to investigate the maximum coverage of the surface with Zn ad-atoms. The full monolayer, characterised by the complete absence of Hads, was achieved only in 0.5 M HF solutions.

Understanding Flood Regime Changes in Europe: a state-of-the-art assessment

There is growing concern that flooding is becoming more frequent and severe in Europe. A better understanding of flood regime changes and their drivers is therefore needed. The paper reviews the current knowledge on flood regime changes in European rivers that has traditionally been obtained through two alternative research approaches. The first approach is the data-based detection of changes in observed flood events. Current methods are reviewed together with their challenges and opportunities. For example, observation biases, the merging of different data sources and accounting for nonlinear drivers and responses. The second approach consists of modelled scenarios of future floods. Challenges and opportunities associated with flood change scenarios are discussed such as fully accounting for uncertainties in the modelling cascade and feedbacks. To make progress in flood change research, we suggest that a synthesis of these two approaches is needed. This can be achieved by focusing on long duration records and flood-rich and flood-poor periods rather than on short duration flood trends only, by formally attributing causes of observed flood changes, by validating scenarios against observed flood regime dynamics, and by developing low-dimensional models of flood changes and feedbacks. The paper finishes with a call for a joint European flood change research network.

Fiscal Regime Shifts in Portugal

We estimate changes in fiscal policy regimes in Portugal with a Markov Switching regression of fiscal policy rules for the period 1978-2007, using a new dataset of fiscal quarterly series. We find evidence of a deficit bias, while repeated reversals of taxes making the budget procyclical. Economic booms have typically been used to relax tax pressure, especially during elections. One-off measures have been preferred over structural ones to contain the deficit during economic crises. The EU fiscal rules prompted temporary consolidation, but did not permanently change the budgeting process.