The Role of Agriculture in Reducing Poverty in Tanzania: A Household Perspective from Rural Kilimanjaro and Ruvuma

This paper explores how farm productivity affects poverty, and how various factor market constraints affect farm productivity. The empirical analysis draws on representative surveys of farm households in Kilimanjaro and Ruvuma, two cash crop growing regions in Tanzania. We find that poorer households do not only possess fewer assets, but are also much less productive. We find that agricultural productivity directly affects household consumption and hence overall poverty and welfare. Stochastic production frontier analysis indicates that many farmers are farming well below best practice in the region. Analysis of allocative efficiency suggests that family labour is substantially over utilized, a sign of considerable excess labour supply. Use of intermediate inputs on the other hand is well below what is commensurate with the estimated value of their marginal productivities. An important reason for low input use is lack of credit to purchase inputs, but difficult access to the inputs themselves, being connected to the economy, and food security and self insurance considerations are also important impediments. Easy access to credit is positively associated with being a member of a savings association or being in a contractual arrangement with a cooperative or firm. The findings support a continuing emphasis on increasing agricultural productivity in designing poverty reduction policies. Better agronomic practices and increased input use will be crucial in this strategy. Financial constraints might be relieved through fostering institutional arrangements facilitating contract enforcement and institutions that facilitate saving by the households themselves. They may also be relieved by the provision of more adequate consumption safety nets.Agricultural development, Factor markets, Rural poverty, Farm productivity, Food Security and Poverty, O13, O120, Q120,

Question-answering, relevance feedback and summarisation : TREC-9 interactive track report

In this paper we report on the effectiveness of query-biased summaries for a question-answering task. Our summarisation system presents searchers with short summaries of documents, composed of a series of highly matching sentences extracted from the documents. These summaries are also used as evidence for a query expansion algorithm to test the use of summaries as evidence for interactive and automatic query expansion

MgB2 tunnel junctions and SQUIDs

Recent advances in the realization and understanding of MgB2 tunnel junctions and SQUIDs are surveyed. High quality MgB2 junctions with suitable tunnel barriers have been realized based on both oriented and epitaxial thin MgB2 films. Multiband transport properties, such as the existence of two energy gaps, phonon spectra and anisotropy have been investigated with these junctions. We review the suitability of different barrier materials and recent advances in obtaining reproducible all-MgB2 Josephson junctions for superconducting electronic circuitry. The development of epitaxial thin films has also led to high-quality multiband MgB2 SQUIDs and magnetometers that operate at high temperatures. The multiband nature of MgB2 provides new phenomena such as the Leggett mode. Manipulating the different phases of the condensates could lead to novel MgB2 devices with phase degrees of freedom.\ud \u

Secants of Lagrangian Grassmannians

We study the dimensions of secant varieties of the Grassmannian of Lagrangian subspaces in a symplectic vector space. We calculate these dimensions for third and fourth secant varieties. Our result is obtained by providing a normal form for four general points on such a Grassmannian and by explicitly calculating the tangent spaces at these four points

A mutli-technique search for the most primitive CO chondrites

As part of a study to identify the most primitive COs and to look for weakly altered CMs amongst the COs, we have conducted a multi-technique study of 16 Antarctic meteorites that had been classified as primitive COs. For this study, we have determined: (1) the bulk H, C and N abundances and isotopes, (2) bulk O isotopic compositions, (3) bulk modal mineralogies, and (4) for some selected samples the abundances and compositions of their insoluble organic matter (IOM). Two of the 16 meteorites do appear to be CMs – BUC 10943 seems to be a fairly typical CM, while MIL 090073 has probably been heated. Of the COs, DOM 08006 appears to be the most primitive CO identified to date and is quite distinct from the other members of its pairing group. The other COs fall into two groups that are less primitive than DOM 08006 and ALH 77307, the previously most primitive CO. The first group is composed of members of the DOM 08004 pairing group, except DOM 08006. The second group is composed of meteorites belonging to the MIL 03377 and MIL 07099 pairing groups. These two pairing groups should probably be combined. There is a dichotomy in the bulk O isotopes between the primitive (all Antarctic finds) and the more metamorphosed COs (mostly falls). This dichotomy can only partly be explained by the terrestrial weathering experienced by the primitive Antarctic samples. It seems that the more equilibrated samples interacted to a greater extent with 16O-poor material, probably water, than the more primitive meteorites

A fast branch-and-prune algorithm for the position analysis of spherical mechanisms

The final publication is available at link.springer.comDifferent branch-and-prune schemes can be found in the literature for numerically solving the position analysis of spherical mechanisms. For the prune operation, they all rely on the propagation of motion intervals. They differ in the way the problem is algebraically formulated. This paper exploits the fact that spherical kinematic loop equations can be formulated as sets of 3 multi-affine polynomials. Multi-affinity has an important impact on how the propagation of motion intervals can be performed because a multi-affine polynomial is uniquely determined by its values at the vertices of a closed hyperbox defined in its domain.Peer ReviewedPostprint (author's final draft

Motion and gravitational radiation of a binary system consisting of an oscillating and rotating coplanar dusty disk and a point-like object

A binary system composed of an oscillating and rotating coplanar dusty disk and a point mass is considered. The conservative dynamics is treated on the Newtonian level. The effects of gravitational radiation reaction and wave emission are studied to leading quadrupole order. The related waveforms are given. The dynamical evolution of the system is determined semi-analytically exploiting the Hamiltonian equations of motion which comprise the effects both of the Newtonian tidal interaction and the radiation reaction on the motion of the binary system in elliptic orbits. Tidal resonance effects between orbital and oscillatory motions are considered in the presence of radiation damping.Comment: 26 pages, 8 figure

Kinks in the Hartree approximation

The topological defects of the lambda phi^4 theory, kink and antikink, are studied in the Hartree approximation. This allows us to discuss quantum effects on the defects in both stationary and dynamical systems. The kink mass is calculated for a number of parameters, and compared to classical, one loop and Monte Carlo results known from the literature. We discuss the thermalization of the system after a kink antikink collision. A classical result, the existence of a critical speed, is rederived and shown for the first time in the quantum theory. We also use kink antikink collisions as a very simple toy model for heavy ion collisions and discuss the differences and similarities, for example in the pressure. Finally, using the Hartree Ensemble Approximation allows us to study kink antikink nucleation starting from a thermal (Bose Einstein) distribution. In general our results indicate that on a qualitative level there are few differences with the classical results, but on a quantitative level there are some import ones.Comment: 20 pages REVTeX 4, 17 Figures. Uses amsmath.sty and subfigure.sty. Final version, fixed typo in published versio

Single use droplet Based Microfluidics – Screening Tools for Biotechnology and Life-Sciences

In the recent years droplet-based microfluidic techniques were developed and used for various screening purposes mainly in the field of life-sciences and biotechnology. Therefore, droplet volumes in a range from pL to μL were used and different technology platforms were necessary to produce the required fluidic devices which made of various materials. Traditionally, lithography combined with etching processes were used to produce precise glass or silicon devices. But, hot embossing and injection molding techniques are better suited for the production of single use devices. Recently, 3D-printing technologies are under development for the generation of individual costumes made microfluidic devices in low numbers for reasonable prices. Here, we present an example for a complex droplet based screening network designed for bacterial screening purposes received by CD-production technologies. General principles of droplet based processing, fluidic devise units and peripheral analytical techniques will be introduced as well as details for the screening of soil bacteria will be given. As an outlook the future microfluidic techniques for monitoring or continuous sampling form large volume bioprocesses will be given