The promises and challenges of biofuels for the poor in developing countries: IFPRI 2005-2006 Annual Report Essay

"In the past several years the changing world energy situation has generated intensive discussion about biofuels, much of it promising a source of environment-friendly energy that would also be a boon to the world's farmers. At the same time skeptics argue that biofuel production will threaten food supplies for the poor and fail to achieve the environmental benefits claimed. Based on the analyses below, we conclude that in order to make a difference in the lives of poor people as both energy producers and consumers, and to make strong environmental and economic contributions, biofuel technology needs further advancement, and investments and policies facilitating agricultural innovation and trade will have to be considered." from TextBiofuels, Poor Developing countries, Small farmers,

Normal frames for non-Riemannian connections

The principal properties of geodesic normal coordinates are the vanishing of the connection components and first derivatives of the metric components at some point. It is well-known that these hold only at points where the connection has vanishing torsion and non-metricity. However, it is shown that normal frames, possessing the essential features of normal coordinates, can still be constructed when the connection is non-Riemannian.Comment: 4 pages, plain TeX. To appear in Class. Quantum Gra

Measurement of the proton light response of various LAB based scintillators and its implication for supernova neutrino detection via neutrino-proton scattering

The proton light output function in electron-equivalent energy of various scintillators based on linear alkylbenzene (LAB) has been measured in the energy range from 1 MeV to 17.15 MeV for the first time. The measurement was performed at the Physikalisch-Technische Bundesanstalt (PTB) using a neutron beam with continuous energy distribution. The proton light output data is extracted from proton recoil spectra originating from neutron-proton scattering in the scintillator. The functional behavior of the proton light output is described succesfully by Birks' law with a Birks constant kB between (0.0094 +/- 0.0002) cm/MeV and (0.0098 +/- 0.0003) cm/MeV for the different LAB solutions. The constant C, parameterizing the quadratic term in the generalized Birks law, is consistent with zero for all investigated scintillators with an upper limit (95% CL) of about 10^{-7} cm^2/MeV^2. The resulting quenching factors are especially important for future planned supernova neutrino detection based on the elastic scattering of neutrinos on protons. The impact of proton quenching on the supernova event yield from neutrino-proton scattering is discussed.Comment: 12 pages, 17 figures, 4 tables, updated version for publication in Eur.Phys.J.

Electronic structure and magnetism in doped semiconducting half-Heusler compounds

We have studied in details the electronic structure and magnetism in M (Mn and Cr) doped semiconducting half-Heusler compounds FeVSb, CoTiSb and NiTiSn (XM$_{x}$Y$_{1-x}$Z) in a wide concentration range using local-spin density functional method in the framework of tight-binding linearized muffin tin orbital method(TB-LMTO) and supercell approach. Our calculations indicate that some of these compounds are not only ferromagnetic but also half-metallic and may be useful for spintronics applications. The electronic structure of the doped systems is analyzed with the aid of a simple model where we have considered the interaction between the dopant transition metal (M) and the valence band X-Z hybrid. We have shown that the strong X-d - M-d interaction places the M-d states close to the Fermi level with the M-t$_{2g}$ states lying higher in energy in comparison to the M-e$_{g}$ states. Depending on the number of available d-electrons, ferromagnetism is realized provided the d-manifold is partially occupied. The tendencies toward ferromagnetic(FM) or antiferromagnetic(AFM) behavior are discussed within Anderson-Hasegawa models of super-exchange and double-exchange. In our calculations for Mn doped NiTiSn, the strong preference for FM over AFM ordering suggests a possible high Curie temperature for these systems.Comment: 14 pages, 6 figure

Déjà vu and the entorhinal cortex: dissociating recollective from familiarity disruptions in a single case patient

Past research has demonstrated a relationship between déjà vu and the entorhinal cortex in patients with wider medial temporal lobe damage. The aim of the present research was to investigate this crucial link in a patient (MR) with a selective lesion to the left lateral entorhinal cortex to provide a more direct exploration of this relationship. Two experiments investigated the experiences of déjà vécu (using the IDEA questionnaire) and déjà vu (using an adapted DRM paradigm) in MR and a set of matched controls. The results demonstrated that MR had quantitatively more and qualitatively richer recollective experiences of déjà vécu. In addition, under laboratory-based déjà vu conditions designed to elicit both false recollection (critical lures) and false familiarity (weakly-associated lures), MR only revealed greater memory impairments for the latter. The present results are therefore the first to demonstrate a direct relationship between the entorhinal cortex and the experience of both déjà vu and déjà vécu. They furthermore suggest that the entorhinal cortex is involved in both weakly-associative false memory as well as strongly-associative memory under conditions that promote familiarity-based processing