Effects of protecting broccoli plants with nonwoven polypropyleno

This investigation was conducted between June and September, in an experimental area, whose coordinates are latitude 21°15'22 south and longitude 48°18'58 east, situated at a mean altitude of 575 m. The soil of the area is classified as Red Latossolo (Commission of Soils, 1960), Haplorthox soil. The effects of two cultivation systems: protection with nonwoven polypropyleno and in an open field, on broccoli cultivars 'Baron', 'Shigimori', 'Pinacco' were evaluated. The experiments were a randomized block experimental design, using a factorial arrangement of 3 (cultivars) x 2 (cultivation systems), with four replicates. The characteristics evaluated were precociousness, longitudinal and transverse diameters of broccoli heads, fresh mass of broccoli heads and number of leaves per plant. The 'Baron' cultivar was more precocious, having its harvest at 86 days after transplanting in both cultivation systems. 'Baron', despite being more precocious, had inferior results in relation to the other cultivars. The open field cultivation system was optimum for cultivars 'Shigimori' and 'Pinacco'.

Inflation and the variability of relative prices in the Caribbean: evidence from panel threshold models

Includes bibliography

Estudo dos efeitos do nitrato de lítio na expansão de argamassas sujeitas a reação álcali-sílica

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Essays on credit rating agencies and the assessment of sovereign risk

Sovereign ratings have only recently regained attention in the academic debate. This seems to be somewhat surprising against the background that their influence is well-known and that rating decisions have often been criticized in the past (as for example during the Asian crisis in the 90s). Sovereign ratings do not only assess the creditworthiness of governments: They are also included in the calculation of ratings for sub-sovereign issuers whereby their rating is usually restricted to the upper bound of the sovereign rating (sovereign ceiling). Earlier studies have also shown that the downgrade of a sovereign often leads to contagion effects on neighbor countries. This study focuses first on misleading incentives in the rating industry before chapter three summarizes the literature on the influence and determinants of sovereign ratings. The fourth chapter explores empirically how ratings respond to changes in sovereign debt across specific country groups. The fifth part focuses on single rating decisions of four selected rating agencies and investigates whether the timing of decisions gives reason for herding behavior. The final chapter presents a reform proposal for the future regulation of the rating industry in light of the aforementioned flaws.rn

Disentangling the impact of seroconversion age and set-point viral load on ART-free HIV survival

Thesis (Master's)--University of Washington, 2016-06

Privatisation, state ownership and productivity:evidence from China

This paper examines the relationship between the transfer of ownership between the public and private sectors of Chinese industry, and its impacts on performance. We link ownership changes to productivity growth, and demonstrate that privatisation contributes significantly. We offer an extension that is generally ignored in the literature, in looking at firms that are taken back into state ownership, and evaluating the productivity growth effects of this. Further, we highlight the well-understood simultaneity problems, and demonstrate the hazard of ignoring the issue by comparing various estimators, including the modified control function approach. In general, the results stress the importance of allowing for such endogeneity when evaluating the productivity effects of ownership change.

Technology flows, outsourcing and productivity:an analysis of UK trade and FDI

By engaging in trade and foreign direct investment (FDI) with foreign partners, a country can access the R&D and related knowledge stocks of other countries (by accident or by design) and so benefit from those stocks of knowledge at a cost lower than that which would be incurred by developing the knowledge internally. This should lead to beneficial ‘spillover’ effects on the productivity of domestic firms. However, the literature on technology spillovers from trade and FDI is ambiguous in its findings. This may in part be because of the assumption in much of the work that trade and FDI flows are homogeneous in their determinants and thus in their effects. We develop a taxonomy of trade and FDI determinants based on R&D intensity and unit labour cost differentials, and test for the presence of spillovers from inward investment and imports on an extensive sample of UK manufacturing plants. We find that both trade and FDI have measurable spillover effects, but the size of these effects varies depending on the technological and labour cost differentials between the UK and its trading partners. There is therefore an identifiable link between the determinants and effects of trade and FDI which the previous literature has not explored. We also find that absorptive capacity matters for spillovers from FDI, but not from trade. Overall, these findings suggest that the productivity effects of FDI are largely restricted to plants with high absorptive capacity, while the productivity effects of imports occur largely among higher-technology plants regardless of their absorptive capacity.

Identification of nonlinear systems by correlation using pseudorandom signals

This thesis is concerned with the measurement of the characteristics of nonlinear systems by crosscorrelation, using pseudorandom input signals based on m sequences. The systems are characterised by Volterra series, and analytical expressions relating the rth order Volterra kernel to r-dimensional crosscorrelation measurements are derived. It is shown that the two-dimensional crosscorrelation measurements are related to the corresponding second order kernel values by a set of equations which may be structured into a number of independent subsets. The m sequence properties determine how the maximum order of the subsets for off-diagonal values is related to the upper bound of the arguments for nonzero kernel values. The upper bound of the arguments is used as a performance index, and the performance of antisymmetric pseudorandom binary, ternary and quinary signals is investigated. The performance indices obtained above are small in relation to the periods of the corresponding signals. To achieve higher performance with ternary signals, a method is proposed for combining the estimates of the second order kernel values so that the effects of some of the undesirable nonzero values in the fourth order autocorrelation function of the input signal are removed. The identification of the dynamics of two-input, single-output systems with multiplicative nonlinearity is investigated. It is shown that the characteristics of such a system may be determined by crosscorrelation experiments using phase-shifted versions of a common signal as inputs. The effects of nonlinearities on the estimates of system weighting functions obtained by crosscorrelation are also investigated. Results obtained by correlation testing of an industrial process are presented, and the differences between theoretical and experimental results discussed for this case;

Technology sourcing and reverse productivity spillovers in the MNE:global or regional phenomenon?

The focus of this paper is the importance of regions in technology transfer by the multinational firm. Specifically, we focus on an issue that has become known as knowledge or technology sourcing via 'reverse spillovers', i.e. productivity effects running from domestic firms to foreign establishments. Traditionally this issue has presented a challenge for international business scholars, both in terms of identifying the phenomenon and in terms of determining the success of the strategy. In this paper we examine these questions within the context of the debate on globalization/regionalization. For a set of some 4500 subsidiaries of multinationals across a wide range of countries we show that reverse productivity spillovers via technology sourcing are significant but that they tend to be concentrated within 'triad regions' rather than across them. We also find that reverse spillovers from host country multinational enterprises are greater than those from other host country firms or from other foreign affiliates. © 2013 British Academy of Management.

Directly unproductive schooling:how country characteristics affect the impact of schooling on growth

The rapid rise in schooling in developing countries in recent decades has been dramatic. However, many cross-country regression analyses of the impact of schooling on economic growth find low and insignificant coefficients. This empirical 'puzzle' contrasts with theoretical arguments that schooling, through raising human capital, should raise income levels. This paper argues that poor results are to be expected when regression samples include countries that vary greatly in their ability to use schooling productively. Data on corruption, the black market premium on foreign exchange and the extent of the brain drain for developing countries are used as indicators of an economy's productive use of schooling. Regression analysis shows that the impact of secondary schooling on economic growth is substantially higher in countries that are adjudged to use schooling productivity.

Quantum and pseudoclassical descriptions of nonrelativistic spinning particles in noncommutative space

We construct a nonrelativistic wave equation for spinning particles in the noncommutative space (in a sense, a theta modification of the Pauli equation). To this end, we consider the nonrelativistic limit of the theta-modified Dirac equation. To complete the consideration, we present a pseudoclassical model (a la Berezin-Marinov) for the corresponding nonrelativistic particle in the noncommutative space. To justify the latter model, we demonstrate that its quantization leads to the theta-modified Pauli equation. We extract theta-modified interaction between a nonrelativistic spin and a magnetic field from such a Pauli equation and construct a theta modification of the Heisenberg model for two coupled spins placed in an external magnetic field. In the framework of such a model, we calculate the probability transition between two orthogonal Einstein-Podolsky-Rosen states for a pair of spins in an oscillatory magnetic field and show that some of such transitions, which are forbidden in the commutative space, are possible due to the space noncommutativity. This allows us to estimate an upper bound on the noncommutativity parameter.

Free-fall in a uniform gravitational field in noncommutative quantum mechanics

We study the free-fall of a quantum particle in the context of noncommutative quantum mechanics (NCQM). Assuming noncommutativity of the canonical type between the coordinates of a two-dimensional configuration space, we consider a neutral particle trapped in a gravitational well and exactly solve the energy eigenvalue problem. By resorting to experimental data from the GRANIT experiment, in which the first energy levels of freely falling quantum ultracold neutrons were determined, we impose an upper-bound on the noncommutativity parameter. We also investigate the time of flight of a quantum particle moving in a uniform gravitational field in NCQM. This is related to the weak equivalence principle. As we consider stationary, energy eigenstates, i.e., delocalized states, the time of flight must be measured by a quantum clock, suitably coupled to the particle. By considering the clock as a small perturbation, we solve the (stationary) scattering problem associated and show that the time of flight is equal to the classical result, when the measurement is made far from the turning point. This result is interpreted as an extension of the equivalence principle to the realm of NCQM. (C) 2010 American Institute of Physics. [doi:10.1063/1.3466812]

Extremal problems on sum-free sets and coverings in tridimensional spaces

Given a prime power q, define c (q) as the minimum cardinality of a subset H of F 3 q which satisfies the following property: every vector in this space di ff ers in at most 1 coordinate from a multiple of a vector in H. In this work, we introduce two extremal problems in combinatorial number theory aiming to discuss a known connection between the corresponding coverings and sum-free sets. Also, we provide several bounds on these maps which yield new classes of coverings, improving the previous upper bound on c (q)

Flat tori, lattices and bounds for commutative group codes

We show that commutative group spherical codes in R(n), as introduced by D. Slepian, are directly related to flat tori and quotients of lattices. As consequence of this view, we derive new results on the geometry of these codes and an upper bound for their cardinality in terms of minimum distance and the maximum center density of lattices and general spherical packings in the half dimension of the code. This bound is tight in the sense it can be arbitrarily approached in any dimension. Examples of this approach and a comparison of this bound with Union and Rankin bounds for general spherical codes is also presented.

Multiple synchronous states in static delay-free mutually connected PLL networks

In many engineering applications, the time coordination of geographically separated events is of fundamental importance, as in digital telecommunications and integrated digital circuits. Mutually connected (MC) networks are very good candidates for some new types of application, such as wireless sensor networks. This paper presents a study on the behavior of MC networks of digital phase-locked loops (DPLLs). Analytical results are derived showing that, even for static networks without delays, different synchronous states may exist for the network. An upper bound for the number of such states is also presented. Numerical simulations are used to show the following results: (i) the synchronization precision in MC DPLLs networks; (ii) the existence of synchronous states for the network does not guarantee its achievement and (iii) different synchronous states may be achieved for different initial conditions. These results are important in the neural computation context. as in this case, each synchronous state may be associated to a different analog memory information. (C) 2010 Elsevier B.V. All rights reserved.