Parametric and Non-Parametric Estimation of Soil Conservation Impact on Productivity in the Northwestern Ethiopian Highlands

The impact of fanya juu bunds on productivity in a high rainfall area in the Ethiopian highlands is analyzed based on data from a cross section household survey with multiple plot observations per household. The results from parametric and non-parametric analysis indicated that productivity from conserved plots was lower than from non-conserved plots. The Oaxaca-Blinder productivity decomposition results showed that there was little difference in plot characteristics between conserved and non-conserved plots, however the returns to those characteristics were higher for non-conserved plots. The sensitivity analysis, increasing fodder grass production on bunds, suggests that there are possibilities to make conserved plots as productive as non-conserved ones. The findings imply that fanya juu bunds may be inappropriate to the local conditions under the existing condition. Farmers in the study area reported that these bunds h ave problem of water-logging, reduce land available for production, and create difficulties in turning the ox-drawn plough due to narrow bund sp acing. Apart from these, there is no attempt made to integrate these bunds with soil fertility management techniques. Overall, these results yield important lessons for future design of conservation technologies that have both physical and economic benefits as well as that are best suited to the local conditions.Yield decomposition, soil conservation, switching regression, stochastic dominance analysis, matching methods, Land Economics/Use, Productivity Analysis, C21, C23, Q12, Q15, Q16,

Tenure Insecurity, Transaction Costs in the Land Lease Market and their Implications for Gendered Productivity Differentials

This study sets out to assess the link between land leasing behavior and productivity differentials between male and female-headed households. A double-moral hazard model allows us to show that landlord's tenure insecurity leads to sub-optimal level of effort on tenant's part, via its impact on the likelihood of contract renewal. The landlord's enforcement ability is also shown to increase the optimal level of effort. The empirical findings support the hypothesis that female heads of households have higher tenant turnover and lower enforcement ability. The results, however, show that contract renewal is not strongly linked to productivity.productivity, female headed households, contract length, enforcement ability, Land Economics/Use, D2, Q12, Q15, C21, C7,

Impact of Land Certification on Land Rental Market Participation in Tigray Region, Northern Ethiopia

There is a renewed interest in whether land reforms can contribute to market development in Africa and whether land reforms can be pro-poor. This paper uses unique household panel data from Tigray region in Ethiopia to assess the impact of the 1998 low-cost land registration and certification reform on land rental market participation over a period of eight years after the reform, using random effects probit and tobit panel data models for land leased out and leased in, while correcting for unobservable heterogeneity and endogeneity of having certificate. The analysis revealed that the land reform contributed to increased land rental market participation. Female-headed households became more willing to rent out land and making land available for more efficient producers. Average areas leased out and leased in increased after certification. The land rental market remained characterised with significant and non-convex transaction costs also after the reform as evidenced by significant state dependence, a low response to own holding size and a high share of non-participation in the land market, leaving room for further improvement.Land certification; land rental market; panel data analysis; unobserved heterogeneity; household response; female-headed households

NLO Corrections to Deeply-Virtual Compton Scattering

We have calculated the NLO corrections to the twist-2 part of the deeply-virtual Compton scattering amplitude. Our results for the transverse and antisymmetric parts agree with recent calculations by Ji and Osborne and by Belitsky and M\"uller. In addition we present NLO results for the longitudinal part of the amplitude.Comment: 8 pages, Latex. Error in polarised gluonic coefficient in Eq.(8) correcte

FOOD-FOR-WORK FOR POVERTY REDUCTION AND THE PROMOTION OF SUSTAINABLE LAND USE: CAN IT WORK?

Food-for-work (FFW) programs are commonly used both for short-term relief and long-term development purposes. In the latter capacity, they are increasingly used for natural resources management projects. Barrett, Holden and Clay (forthcoming) assess the suitability of FFW programs as insurance to cushion the poor against short-term, adverse shocks that could, in the absence of a safety net, have permanent repercussions. In this paper we explore the complementary question of FFW programs' potential to reduce poverty and promote sustainable land use in the longer run through induced changes in investment patterns. FFW programs commonly aim to produce or maintain potentially valuable public goods necessary to stimulate productivity and thus income growth. Among the most common projects are road building, reforestation, and the installation of terracing or irrigation. In the abstract, public goods such as these are unambiguously good. There is a danger, however, that such programs could discourage private soil and water conservation and crowd out private investment. How important are such effects and when are these effects small or large and when and how can they be reduced? How do market characteristics, timing and design of FFW programs affect this? When, where and how can FFW programs more efficiently reduce poverty and promote more sustainable land management? The paper aims to answer these questions. Much recent empirical research has focused on the shorter-term targeting issue of whether FFW and related workfare programs efficiently target the poor (Dev 1995, Von Braun 1995, Webb 1995, Subbarao 1997, Clay et al. 1998, Devereux 1999, Jayne et al. 1999, Ravallion 1999, Teklu and Asefa 1999, Atwood et al. 2000, Gebremedhin and Swinton 2000, Haddad and Adato 2001, Jalan and Ravallion 2001). Much less research has been focused on the longer-term effects of FFW. Yet the large share of hunger worldwide arises due to chronic deprivation and vulnerability, not short-term shocks (Speth 1993, Barrett 2002). Also most of the FFW programs in Ethiopia have long-term development goals and are formally distinguished from the disaster relief FFW programs (Aas and Mellemstrand 2002). It is therefore appropriate to evaluate these programs based on their long-term goals and not only on the basis of short-term targeting. In a case study in Tigray Aas and Mellemstrand (2002) found that the FFW recipients considered the long-term benefits of FFW as more important than the short-term benefits of food provision. FFW programs may produce valuable public goods. For example, Von Braun et al. (1999) report multiplier effects of a FFW-built road in the Ethiopian lowlands. Public provision of public goods may be socially desirable because private investment in soil and water conservation and tree planting may be well below socially optimal levels due to poverty and market imperfections (Holden, Shiferaw and Wik 1998, Holden and Shiferaw 2002, Holden and Yohannes 2002, Pender and Kerr 1998), tenure insecurity (Gebremedhin and Swinton 2000, Holden, Benin, Shiferaw and Pender 2003), lack of technical knowledge and coordination problems across farms (Hagos and Holden 2002). There is, however, also a danger that FFW programs crowd out private investments (Gebremedhin and Swinton 2000). We analyze these issues using multiple methods. First, section II introduces a simple theoretical framework for understanding the analytically ambiguous effects of FFW programs on sustainable land use patterns. We first present the basic intuition in a static framework to illustrate the selection, crowding out and targeting issues, before generalizing it to a dynamic model to illustrate the possible insurance and crowding in effects of FFW. Section III then uses an applied, dynamic bio-economic farm household model applied to a less-favoured area in Ethiopia to investigate via numerical simulation how household welfare and land use patterns vary with changes in environmental and FFW program design parameters. Section IV presents econometric evidence based on survey panel data from northern Ethiopia to assess the relationship between FFW and private investment in conservation. Section V discusses our findings and fleshes them out a bit with further empirical evidence. Section VI concludes.Food Security and Poverty, Q18, O1, Q2, I1,

Electronic properties of Si/Si1–x–yGexCy heterojunctions

We have used admittance spectroscopy and deep-level transient spectroscopy to characterize electronic properties of Si/Si1–x–yGexCy heterostructures. Band offsets measured by admittance spectroscopy for compressively strained Si/Si1–x–yGexCy heterojunctions indicate that incorporation of C into Si1–x–yGexCy lowers both the valence- and conduction-band edges compared to those in Si1–xGex by an average of 107 ± 6 meV/% C and 75 ± 6 meV/% C, respectively. Combining these measurements indicates that the band alignment is type I for the compositions we have studied, and that these results are consistent with previously reported results on the energy band gap of Si1–x–yGexCy and with measurements of conduction band offsets in Si/Si1–yCy heterojunctions. Several electron traps were observed using deep-level transient spectroscopy on two n-type heterostructures. Despite the presence of a significant amount of nonsubstitutional C (0.29–1.6 at. %), none of the peaks appear attributable to previously reported interstitial C levels. Possible sources for these levels are discussed

Structural design of an in-line bolted joint for the space shuttle solid rocket motor case segments

Results of a structural design study of an in-line bolted joint concept which can be used to assemble Space Shuttle Solid Rocket Motor (SRM) case segments are presented. Numerous parametric studies are performed to characterize the in-line bolted joint behavior as major design variables are altered, with the primary objective always being to keep the inside of the joint (where the O-rings are located) closed during the SRM firing. The resulting design has 180 1-inch studs, an eccentricity of -0.5 inch, a flange thickness of 3/4 inch, a bearing plate thickness of 1/4 inch, and the studs are subjected to a preload which is 70% of ultimate. The mass penalty per case segment joint for the in-line design is 346 lbm more than the weight penalty for the proposed capture tang fix