Damage level of the two-spotted spider mite Tetranychus urticae Koch (acari: tetranychidae) in soybeans

Among phytophagous spider mites, the two-spotted spider mite Tetranychus urticae Koch, 1836 is one of the most important agricultural pests, not only because of the damage it causes, but also because it has a wide host range, infesting many commercial crops such as leafy greens, cotton, beans, and soybeans, among others. This study was carried out in a greenhouse of the Faculdade de Ciências Agrárias (FCA) of the Universidade Federal da Grande Dourados (UFGD), located in the city of Dourados, state of Mato Grosso do Sul. The experiment was arranged in a randomized block design with 5 treatments and 4 replicates. The treatments consisted of 5 levels in percentage of chlorotic symptoms (indicating mite damage): 0%, 25%, 50%, 75%, and 100%. All of the characteristics evaluated, except for number of pods per plant, the number of seeds per plant, the total weight (productivity), and the weight of 1000 seeds, were significantly influenced by the different levels of chlorotic symptoms. The economic damage level for the two-spotted spider mite Tetranychus urticae, according to the equation y = 66.63-0.51 x, based on the price of US$ 11.00 per bag of soybeans and a control cost of US$ 16.00, would be 15.80% chlorotic symptoms. At a price of US$ 29.00 per bag with the same control cost, the economic damage level would be 13% of chlorotic symptoms.

Efficiency of nitrogen fertilizer applied at corn sowing in contrasting growing seasons in Paraguay

In order to select soil management practices that increase the nitrogen-use efficiency (NUE) in agro-ecosystems, the different indices of agronomic fertilizer efficiency must be evaluated under varied weather conditions. This study assessed the NUE indices in no-till corn in southern Paraguay. Nitrogen fertilizer rates from 0 to 180 kg ha-1 were applied in a single application at corn sowing and the crop response investigated in two growing seasons (2010 and 2011). The experimental design was a randomized block with three replications. Based on the data of grain yield, dry matter, and N uptake, the following fertilizer indices were assessed: agronomic N-use efficiency (ANE), apparent N recovery efficiency (NRE), N physiological efficiency (NPE), partial factor productivity (PFP), and partial nutrient balance (PNB). The weather conditions varied largely during the experimental period; the rainfall distribution was favorable for crop growth in the first season and unfavorable in the second. The PFP and ANE indices, as expected, decreased with increasing N fertilizer rates. A general analysis of the N fertilizer indices in the first season showed that the maximum rate (180 kg ha-1) obtained the highest corn yield and also optimized the efficiency of NPE, NRE and ANE. In the second season, under water stress, the most efficient N fertilizer rate (60 kg ha-1) was three times lower than in the first season, indicating a strong influence of weather conditions on NUE. Considering that weather instability is typical for southern Paraguay, anticipated full N fertilization at corn sowing is not recommended due the temporal variability of the optimum N fertilizer rate needed to achieve high ANE.

Gill Nets of Kerala

The fishing industry the world over is passing through a critical situation.The landings of marine fishes seemed to have reached saturation in major fishing areas of the world.As a general rule fisheries employing fishing gear and techniques used by small scale and artisanal fishermen either from shore or from onboard small fishing craft come under small-scale fisheries.This study on gill nets of Kerala, the fishing method depended upon by maximum fishermen of the state focuses on the importance of this selective and low energy fishing method in the marine fishing sector of the state.The study opens with the conceptual framework by briefly reviewing the crisis in the marine fisheries sector. Maximum fishermen depend upon gill net, which is, an important selective and low energy fishing gear. A review of relevant literature on aspects such as material, selectivity and techno-economic efficiency together with scope and main objectives of the study form the major part of the compass of the introductory chapter.This survey provided the inputs for selection of centres. The chapter presents the basis for selection of sample centres, sample units and methodology for field and experimental study.The subject matter of the fourth chapter is a basic study on gear aterials. The weathering resistance, which is an important criterion to assess the material performance, was studied for polyamide monofilament in comparison to polyamide multifilament and polyethylene twisted monofilament.The study provides supporting evidence of oxidation and characteristic C-O stretching in polyethylene and cyclic lactam .formation and presence of OH in polyamide.The study indicates that small mesh gill netting can be encouraged as a selective fishing method in the inshore waters with restrained use of 30 and 32 mm mesh sizes. The economic efficiency was assessed using standard indices such as rate of return, internal rate of return, pay back period, fishery income, energy efficiency and factor productivity. The effect of size and cost of capital and cost of production on the economics of operation is also discussed in this chapter. It was observed that level of technology did not have direct effect on economic performance.

On the long run effects of barriers to trade

We study the macroeconomic effects of international trade policy by integrating a Hecksher-Ohlin trade model into an optimal-growth framework. The model predicts that a more open economy will have higher factor productivity. Furthermore, there is a "selective development trap," an additional steady state with low income, to which countries may or may not converge, depending on policy. Income at the development trap falls as trade barriers increase. Hence, cross-country differences in barriers to trade may help explain the dispersion of per-capita income observed across countries. The effects are quantified and we show that protectionism can explain a relevant fraction of TFP and long-run income differentials across countries.

On the growth effects of barriers to trade

We study the macroeconomic effects of international trade policy by integrating a Hecksher-Ohlin trade model into an optimal-growth framework. The model predicts that an open economy will have higher factor productivity and faster growth. Also, under protectionist policies there may be “development traps,” or additional steady states with low income. In the last case, higher tariffs imply lower incomes, so that the large cross-country differences in barriers to trade may explain part of the huge dispersion of per capita income observed across countries. The model simulation shows that the link between trade and macroeconomic performance may be quantitatively important.

Malthus to Solow

A unified growth theory is developed that accounts for the roughly constant living standards displayed by world economies prior to 1800 as well as the growing living standards exhibited by modem industrial economies. Our theory also explains the industrial revolution, which is the transition from an era when per capita incomes are stagnant to one with sustained growth. This transition is inevitable given positive rates oftotal factor productivity growth. We use a standard growth mode1 with one good and two available techno10gies. The first, denoted the "Malthus" technology, requires 1and, labor and reproducible capital as inputs. The second, denoted the "Solow" technology, does not require land. We show that in the earIy stages of development, only the Malthus technology is used and, due to population growth, living standards are stagnant despite technological progresso Eventually, technological progress causes the Solow technology to become profitable and both technologies are employed. At this point, living standards improve since population growth has less influence on per capita income growth. In the limit, the economy behaves like a standard Solow growth model.

Elasticity of substitution between capital and labor: a panel data approach

This paper estimates the elasticity of substitution of an aggregate production function. The estimating equation is derived from the steady state of a neoclassical growth model. The data comes from the PWT in which different countries face different relative prices of the investment good and exhibit different investment-output ratios. Then, using this variation we estimate the elasticity of substitution. The novelty of our approach is that we use dynamic panel data techniques, which allow us to distinguish between the short and the long run elasticity and handle a host of econometric and substantive issues. In particular we accommodate the possibility that different countries have different total factor productivities and other country specific effects and that such effects are correlated with the regressors. We also accommodate the possibility that the regressors are correlated with the error terms and that shocks to regressors are manifested in future periods. Taking all this into account our estimation resuIts suggest that the Iong run eIasticity of substitution is 0.7, which is Iower than the eIasticity that had been used in previous macro-deveIopment exercises. We show that this lower eIasticity reinforces the power of the neoclassical mo deI to expIain income differences across countries as coming from differential distortions.

Adubação organomineral e biofertilização líquida na produção de frutos de pinheira ( Annona squamosa L.) no submédio São Francisco, Brasil

The organic production systems based on natural processes do not allow the use of synthetic fertilizers with a high solubility, so it is required the use of technologies in accordance with the organic production legislation in order to make the technical, economical and environmental sustainable activities viable. To evaluate the effects of the usage of mineral and organic natural fertilizers, associated with liquid biofertilizers (BLE= enriched liquid biofertilizer and BF= leaf biofertilizers) on the production of the sugar apple fruit crop Annona squamosa L., replacing totally the chemical fertilizers, used by conventional farming systems, a nine year old orchard was driven in the irrigated plot n degrees 1295, irrigated project Nilo Coelho, district of Petrolina - PE. The experiment was carried out from September 2005 to February 2006. The experimental design was done through randomized blocks with eight treatments and four replications in plots of three plants each, with 96 plants in total. The treatments were the following: T(1) - plants with no fertilizer; T(2) - 60 g de N + 32 g de P(2)O(5) + 48 g de K(2)O; T(3) - 90g de N + 32 g de P(2)O(5) + 48 g de K(2)O; T(4) - 30 g de N + 32 g de P(2)O(5) + 48 g de K(2)O + 15 L de BLE + BF a 5 %; T(5) - 60g de N + 32 g de P(2)O(5) + 48 g de K(2)O + 30 L de BLE + BF a 5 %; T(6)- 90g de N + 32 g de P(2)O(5) + 48 g de K(2)O + 45 L de BLE + BF a 5 %; T(7) - 120g de N + 32 g de P(2)O(5) + 48 g de K(2)O + 60 L de BLE + BF a 5 %; T(8) - 150 g de N + 32 g de P(2)O(5) + 48 g de K(2)O + 75 L de BLE + BF a 5 % The fruit growth analyses (diameter and average length), total yield, productivity, average fruit weight, average number of fruits, fresh weight of the skin and pulp and dry weight of the fruits were used to evaluate the experiment. The results were relevant to the total production, fresh weight of the skin and dry weight of the fruits. The use of organominerals associated with liquid fertilizers increased significantly the productivity in values ranging from 10.44% (T(5) = 1.98 t ha(-1)) to 24.52 % (T(7) = 12.34 %). The treatment T(3) stood out (90g de N + 32g de P(2)O(5) + 48g de K(2)O) with a higher production than the control. The fruit weight increased in the fertilized treatments, with values increasing from treatment (T(2) = 5.26 %) to the treatment (T(7) = 12.34 %) in relation to the control. The fruit development was characterized by an average growth increase of 82 % in length and 84 % in diameter until the 56(th) day, with a sigmoidal growth pattern.

Potential output in Latin America: a standard approach for the 1950-2002 period

Includes bibliography

Potencial de uso de gramíneas como substrato pasteurizado no cultivo do cogumelo Pleurotus ostreatus (Jacq.) P. Kumm

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Expression profiling und rationale Expressionsoptimierung am Beispiel eines prokaryontischen Wirt-,Vektor-Systems

Durch globale Expressionsprofil-Analysen auf Transkriptom-, Proteom- oder Metabolom-Ebene können biotechnologische Produktionsprozesse besser verstanden und die Erkenntnisse für die zielgerichtete, rationale Optimierung von Expressionssystemen genutzt werden. In der vorliegenden Arbeit wurde die Überexpression einer Glukose-Dehydrogenase (EC 1.1.5.2), die von der Roche Diagnostics GmbH für die diagnostische Anwendung optimiert worden war, in Escherichia coli untersucht. Die Enzymvariante unterscheidet sich in sieben ihrer 455 Aminosäuren vom Wildtyp-Enzym und wird im sonst isogenen Wirt-/Vektor-System in signifikant geringeren Mengen (Faktor 5) gebildet. Das prokaryontische Expressionssystem wurde auf Proteom-Ebene charakterisiert. Die 2-dimensionale differenzielle Gelelektrophorese (DIGE) wurde zuvor unter statistischen Aspekten untersucht. Unter Berücksichtigung von technischen und biologischen Variationen, falsch-positiven (α-) und falsch-negativen (β-) Fehlern sowie einem daraus abgeleiteten Versuchsdesign konnten Expressionsunterschiede als signifikant quantifiziert werden, wenn sie um den Faktor ≥ 1,4 differierten. Durch eine Hauptkomponenten-Analyse wurde gezeigt, dass die DIGE-Technologie für die Expressionsprofil-Analyse des Modellsystems geeignet ist. Der Expressionsstamm für die Enzymvariante zeichnete sich durch eine höhere Variabilität an Enzymen für den Zuckerabbau und die Nukleinsäure-Synthese aus. Im Expressionssystem für das Wildtyp-Enzym wurde eine unerwartet erhöhte Plasmidkopienzahl nachgewiesen. Als potenzieller Engpass in der Expression der rekombinanten Glukose-Dehydrogenase wurde die Löslichkeitsvermittlung identifiziert. Im Expressionsstamm für das Wildtyp-Enzym wurden viele Proteine für die Biogenese der äußeren Membran verstärkt exprimiert. Als Folge dessen wurde ein sog. envelope stress ausgelöst und die Zellen gingen in die stationäre Wuchsphase über. Die Ergebnisse der Proteomanalyse wurden weiterführend dazu genutzt, die Produktionsleistung für die Enzymvariante zu verbessern. Durch den Austausch des Replikationsursprungs im Expressionsvektor wurde die Plasmidkopienzahl erhöht und die zelluläre Expressionsleistung für die diagnostisch interessantere Enzymvariante um Faktor 7 - 9 gesteigert. Um die Löslichkeitsvermittlung während der Expression zu verbessern, wurde die Plasmidkopienzahl gesenkt und die Coexpression von Chaperonen initiiert. Die Ausbeuten aktiver Glukose-Dehydrogenase wurden durch die Renaturierung inaktiven Produkts aus dem optimierten Expressionssystem insgesamt um einen Faktor von 4,5 erhöht. Somit führte im Rahmen dieser Arbeit eine proteombasierte Expressionsprofil-Analyse zur zielgerichteten, rationalen Expressionsoptimierung eines prokaryontischen Modellsystems.

Geochemistry of abyssal peridotites from ODP Hole 209-1274A

Aqueous dihydrogen (H2,aq) is produced in copious amounts when seawater interacts with peridotite and H2O oxidizes ferrous iron in olivine to ferric iron in secondary magnetite and serpentine. Poorly understood in this process is the partitioning of iron and its oxidation state in serpentine, although both impose an important control on dihydrogen production. We present results of detailed petrographic, mineral chemical, magnetic and Mößbauer analyses of partially to fully serpentinized peridotites from the Ocean Drilling Program (ODP) Leg 209, Mid-Atlantic Ridge (MAR) 15°N area. These results are used to constrain the fate of iron during serpentinization and are compared with phase equilibria considerations and peridotite-seawater reaction path models. In samples from Hole 1274A, mesh-rims reveal a distinct in-to-out zoning from brucite at the interface with primary olivine, followed by a zone of serpentine + brucite ± magnetite and finally serpentine + magnetite in the outermost mesh-rim. The compositions of coexisting serpentine (Mg# 95) and brucite (Mg# 80) vary little throughout the core. About 30-50% of the iron in serpentine/brucite mesh-rims is trivalent, irrespective of subbasement depth and protolith (harzburgite versus dunite). Model calculations suggest that both partitioning and oxidation state of iron are very sensitive to temperature and water-to-rock ratio during serpentinization. At temperatures above 330 °C the dissolution of olivine and coeval formation of serpentine, magnetite and dihydrogen depends on the availability of an external silica source. At these temperatures the extent of olivine serpentinization is insufficient to produce much hydrogen, hence conditions are not reducing enough to form awaruite. At T < 330 °C, hydrogen generation is facilitated by the formation of brucite, as dissolution of olivine to form serpentine, magnetite and brucite requires no addition of silica. The model calculations suggest that the iron distribution observed in serpentine and brucite is consistent with formation temperatures ranging from <150 to 250 °C and bulk water-to-rock ratios between 0.1 and 5. These conditions coincide with peak hydrogen fugacities during serpentinization and are conducive to awaruite formation during main stage serpentinization. The development of the common brucite rims around olivine is either due to an arrested reaction olivine -> brucite -> serpentine + brucite, or reflects metastable olivine-brucite equilibria developing in the strong gradient in silica activity between orthopyroxene (talc-serpentine) and olivine (serpentine-brucite).

Diversification economies and specialisation efficiencies in a mixed food and coffee smallholder farming system in Papua New Guinea

Smallholder farming systems in Papua New Guinea are characterised by an integrated set of cash cropping and subsistence food cropping activities. In the Highlands provinces, the subsistence food crop sub-system is dominated by sweet potato production. Coffee dominates the cash cropping sub-system, but a limited number of food crops are also grown for cash sale. The dynamics between sub-systems can influence the scope for complementarity between, and technical efficiency of, their operations, especially in light of the seasonality of demand for household labour and management inputs within the farming system. A crucial element of these dynamic processes is diversification into commercial agricultural production, which can influence factor productivity and the efficiency of crop production where smallholders maintain a strong production base in subsistence foods. In this study we use survey data from households engaged in coffee and food crop production in the Benabena district of Eastern Highlands Province to derive technical efficiency indices for each household over two years. A stochastic input distance function approach is used to establish whether diversification economies exist and whether specialisation in coffee, subsistence food or cash food production significantly influences technical efficiency on the sampled smallholdings. Diversification economics are weakly evident between subsistence food production and both coffee and cash food production, but diseconomies of diversification are discerned between coffee and cash food production. A number of factors are tested for their effects on technical efficiency. Significant technical efficiency gains are made from diversification among broad cropping enterprises.

Patterns of Root Dynamics in Mangrove Forests Along Environmental Gradients in the Florida Coastal Everglades, USA

Patterns of mangrove vegetation in two distinct basins of Florida Coastal Everglades (FCE), Shark River estuary and Taylor River Slough, represent unique opportunities to test hypotheses that root dynamics respond to gradients of resources, regulators, and hydroperiod. We propose that soil total phosphorus (P) gradients in these two coastal basins of FCE cause specific patterns in belowground biomass allocation and net primary productivity that facilitate nutrient acquisition, but also minimize stress from regulators and hydroperiod in flooded soil conditions. Shark River basin has higher P and tidal hydrology with riverine mangroves, in contrast to scrub mangroves of Taylor basin with more permanent flooding and lower P across the coastal landscape. Belowground biomass (0–90 cm) of mangrove sites in Shark River and Taylor River basins ranged from 2317 to 4673 g m-2, with the highest contribution (62–85%) of roots in the shallow root zone (0–45 cm) compared to the deeper root zone (45–90 cm). Total root productivity did not vary significantly among sites and ranged from 407 to 643 g m-2 y-1. Root production in the shallow root zone accounted for 57–78% of total production. Root turnover rates ranged from 0.04 to 0.60 y-1 and consistently decreased as the root size class distribution increased from fine to coarse roots, indicating differences in root longevity. Fine root biomass was negatively correlated with soil P density and frequency of inundation, whereas fine root turnover decreased with increasing soil N:P ratios. Lower P availability in Taylor River basin relative to Shark River basin, along with higher regulator and hydroperiod stress, confirms our hypothesis that interactions of stress from resource limitation and long duration of hydroperiod account for higher fine root biomass along with lower fine root production and turnover. Because fine root production and organic matter accumulation are the primary processes controlling soil formation and accretion in scrub mangrove forests, root dynamics in the P-limited carbonate ecosystem of south Florida have a major controlling role as to how mangroves respond to future impacts of sealevel rise.