Aya Suzuki

Chiral Metal Nanoparticle Systems as Heterogeneous Catalysts beyond Homogeneous Metal Complex Catalysts for Asymmetric Addition of Arylboronic Acids to α,β-Unsaturated Carbonyl Compounds

We describe the use of chiral metal nanoparticle systems, as novel heterogeneous chiral catalysts for the asymmetric 1,4-addition of arylboronic acids to α,β-unsaturated carbonyl compounds, as representative C-C bond-forming reactions. The reactions proceeded smoothly to afford the corresponding β-arylated products in high to excellent yields and outstanding enantioselectivities with wide substrate scope. Remarkably, the nanoparticle catalysts showed performance in terms of yield, enantioselectivity, and catalytic turnover that was superior to that of the corresponding homogeneous metal complexes. The catalyst can be successfully recovered and reused in a gram-scale synthesis with low catalyst loading without significant loss of activity. The nature of the active species was investigated, and we found that characteristic features of the nanoparticle system were totally different from those of the metal complex system.

Optimal Investment in Transportation Infrastructure When Middlemen Have Market Power: A Developing-Country Analysis

Transportation costs and buyer market power reduce prices and income received by farmers in developing countries. Transportation costs directly affect the marketing margin and also exacerbate market power by limiting farmers’ access to buyers. This article develops a multistage spatial model to determine optimal investment in transportation improvements, taking account of impacts on marketing costs and competition. The beneficial impact of investments from farmers’ perspective is mainly through enhanced competition, meaning significant under-investment may occur if this effect is ignored. However, the optimal investment depends on the relative importance of transportation costs; in some settings, transportation improvements reduce farm prices because buyers rationally over-compensate farmers for these costs. Copyright 2007, Oxford University Press.

On the Possibility of Rice Green RevolutionGreen Revolution in Rainfed Areas in Northern Ghana: An Assessment of a Management Training Program

This chapter investigates the impact of technical intervention on the adoption of a set of improved rice production technologies, as well as on productivity and profit for smallholders in rainfed lowland areas in Northern Ghana. The key finding is that productivity and profit are significantly enhanced when modern varieties (MVs) and chemical fertilizer are adopted, coupled with water control techniques. This is essentially the transfer of the Asian Green Revolution to sub-Saharan Africa. Such transfer, however, is not truly successful unless information about the use of MVs and fertilizer are directly disseminated by extension activities.

Industrial Development through Takeovers and Exits: The Case of the Cut Flower Exporters in Ethiopia

The exit and takeover of firms influence the structure and economic efficiency of an industry. The existing literature suggests that firms gradually learn about their own productivity. Some stagnate and ultimately exit if they encounter unfavorable prospects; others survive and grow. This selection process implies that the probability of firm exit initially increases with firm age as learning progresses before it eventually falls as learning is completed. We use a firm-level panel of Ethiopia’s cut flower industry to confirm this theoretical implication. The empirical results also suggest that takeover improves productivity and profitability of average firms endowed with a favorable business environment.

Polysilane-Immobilized Rh–Pt Bimetallic Nanoparticles as Powerful Arene Hydrogenation Catalysts: Synthesis, Reactions under Batch and Flow Conditions and Reaction Mechanism

Hydrogenation of arenes is an important reaction not only for hydrogen storage and transport but also for the synthesis of functional molecules such as pharmaceuticals and biologically active compounds. Here, we describe the development of heterogeneous Rh-Pt bimetallic nanoparticle catalysts for the hydrogenation of arenes with inexpensive polysilane as support. The catalysts could be used in both batch and continuous-flow systems with high performance under mild conditions and showed wide substrate generality. In the continuous-flow system, the product could be obtained by simply passing the substrate and 1 atm H2 through a column packed with the catalyst. Remarkably, much higher catalytic performance was observed in the flow system than in the batch system, and extremely strong durability under continuous-flow conditions was demonstrated (>50 days continuous run; turnover number >3.4 × 105). Furthermore, details of the reaction mechanisms and the origin of different kinetics in batch and flow were studied, and the obtained knowledge was applied to develop completely selective arene hydrogenation of compounds containing two aromatic rings toward the synthesis of an active pharmaceutical ingredient.

Reducing Agricultural Income Vulnerabilities through Agroforestry Training: Evidence from a Randomized Field Experiment in Indonesia

Although agroforestry is recognised as a means to stabilise farm income, little work has been done to differentiate farmers based on their incomes, their capacity to diversify crops, and the economic outcomes of agroforestry adoption. By distinguishing between high- and low-income farmers, this paper examines how agricultural training affects agroforestry promotion, and evaluates its relevance for the poor, the extent of its adoption, and its economic consequences. We found that although training generally increased participants’ knowledge of agroforestry, it increased crop diversity only for low-income participants. We also detected the presence of information spillovers from participants to non-participants, which may increase crop diversity among non-participants and consequently reduce the measurable impact of training. When income heterogeneity is considered, we found that the low-income participants benefited more from increasing their incomes and expanding their social networks than the higher-income participants. We also found that agroforestry adoption helped to reduce income volatility.

Better management practices and their outcomes in shrimp farming: evidence from small-scale shrimp farmers in Southern Vietnam

Despite the growth of aquaculture exports from developing countries to developed countries in recent years, a high percentage of these products are rejected at developed countries’ ports because of non-compliance with international standards. This paper presents a case study of the shrimp aquaculture sector in Vietnam to examine the factors behind the persistence of such port rejections. In particular, we focus on why the so-called better management practices (BMPs) are not appropriately adopted by many farmers and examine whether the number and types of information sources matter in farmers’ decisions on BMP adoption and whether BMP adoption actually leads to better performances. On the basis of our estimation using primary data collected in Southern Vietnam, we find that information sources and training experiences indeed matter in the adoption of a higher number of BMPs and that BMP adoption indeed reduces the possibility of disease outbreaks. These results prove the effectiveness of BMPs and suggest the importance of disseminating knowledge regarding them to farmers through experts.

The Fresh Pineapple Export Industry in Ghana: The Role of Smallholders in the High-Value Horticultural Supply Chain

Agricultural markets in developing countries have experienced many changes over the past decades (Jaffee and Morton, 1995; Dolan and Humphrey, 2000; Minot and Ngigi, 2004; World Bank, 2008). The domestic agricultural supply chains, which were formerly dominated by parastatal organizations, have been liberalized in many countries due to a series of policies such as the Structural Adjustment Programme. This invited the massive entry of private traders, making the domestic market more competitive. At the international level, many tariff barriers have been mitigated as preferential treaties have been signed for developing countries. The role of retailers (both in developing and developed countries) in procuring the raw produce from farmers has also increased. In addition, improved modes of transport have also reduced transportation costs. All these changes have contributed to providing farmers in developing countries with greater access to global markets. On the other hand, competition in global markets is becoming unprec-edentedly intense, and non-tariff barriers in the form of stricter food quality standards and traceability requirements have been increasing (Jaffee and Henson, 2004; Henson et al., 2008). This trend may be causing small-scale farmers in developing countries to become marginalized from global markets.