Paving the Way for Development: The Impact of Road Infrastructure on Agricultural Production and Household Wealth in the Democratic Republic of Congo

Given its vast land resources and favorable water supply, the Democratic Republic of Congo's (DRC) natural agricultural potential is immense. However, the economic potential of the sector is handicapped by one of the most dilapidated transport systems in the developing world (World Bank, 2006). Road investments are therefore a high priority in the government's investment plans, and those of its major donors. Whilst these are encouraging signs, very little is known about how the existing road network constrains agricultural and rural development, and how these new road investments would address these constraints. To inform this issue the present paper primarily employs GIS-based data to assess the impact of market access on agricultural and rural development (ARD). Compared to existing work, however, the paper makes a number of innovations to improve and extend the generic techniques used to estimate the importance of market access for ARD. First, the DRC road network data is augmented with survey-based data from Minten and Kyle (1999) on agricultural transport times to calculate improved “market access” measures for the DRC. Second, we follow Dorosh et al (2009) in estimating the long run relationship between market access and agricultural production, although we also investigate the relationship with household wealth. Finally, we run simulations of how proposed infrastructure investments would affect market access, and how market access would in turn affect agricultural production and household wealth.Infrastructure, market access, road and river transport, agricultural production, poverty., Agricultural and Food Policy, Crop Production/Industries, Food Security and Poverty, Production Economics,

Evolution of YidC/Oxa1/Alb3 insertases: three independent gene duplications followed by functional specialization in bacteria, mitochondria and chloroplasts

Members of the YidC/Oxa1/Alb3 protein family facilitate the insertion, folding and assembly of proteins of the inner membranes of bacteria and mitochondria and the thylakoid membrane of plastids. All homologs share a conserved hydrophobic core region comprising five transmembrane domains. On the basis of phylogenetic analyses, six subgroups of the family can be distinguished which presumably arose from three independent gene duplications followed by functional specialization. During evolution of bacteria, mitochondria and chloroplasts, subgroup-specific regions were added to the core domain to facilitate the association with ribosomes or other components contributing to the substrate spectrum of YidC/Oxa1/Alb3 proteins

The bulge-disk orthogonal decoupling in galaxies: NGC 4698 and NGC 4672

We report the case of the geometrical and kinematical decoupling between the bulge and the disk of the Sa galaxy NGC 4698. The R-band isophotal map of this spiral shows that the bulge structure is elongated perpendicularly to the major axis of the disk. At the same time a central stellar velocity gradient is found along the major axis of the bulge. We also present the Sa NGC 4672 as good candidate of a spiral hosting a bulge and a disk orthogonally decoupled with respect to one other. This decoupling of the two fundamental components of a visible galaxy suggests that the disk could represent a second event in the history of early-type spirals.Comment: 4 pages, 3 figures (LaTeX, cupconf.sty). To appear in "The Formation of Bulges" C. M. Carollo, H. C. Ferguson, R. F. G. Wyse (eds.), Cambridge University Pres

The Circumnuclear Ring of Ionized Gas in NGC3593

We present the results of narrow-band Halpha+NII imaging of the early-type spiral NGC3593 in combination with a study of the flux radial profiles of the NII (lambda: 654.80, 658.34 nm), Halpha, and SII (lambda: 671.65, 673.08 nm) emission lines along its major axis. The galaxy is known to contain two counterrotating stellar discs of different size and luminosity. We find that the Halpha emission mainly derives from a small central region of 57 arcsec x 25 arcsec. It consists of a filamentary pattern with a central ring. This has a diameter of about 17 arcsec (~ 0.6/h kpc) and it contributes about half of the total Halpha flux. The ring is interpreted as the result of the interaction between the acquired retrograde gas which later formed the smaller counterrotating stellar disc and the pre-existing prograde gas of the galaxy.Comment: Accepted for pubblication in Astronomy and Astrophysics; one latex file (corsini.tex), and 2 encapsulated postscript figures (corsini_fig1.ps,corsini_fig2.ps). To be compiled with aa.cls latex2e macro style (pslatex option): 6 pages after latex compilatio

La producción académica sobre educación en la Argentina : Un análisis del período 2001-2010

En esta ponencia se presentan resultados parciales de una investigación que se propone realizar un mapeo del campo de la producción de conocimiento en educación, tanto en lo referido a las agencias y los agentes productores como de las formas de producción y difusión de conocimientos, en el período 2001-2010. Se realizó un relevamiento de las publicaciones de académicos de instituciones argentinas en el área de la educación, incluyendo libros y artículos en las revistas argentinas especializadas y en una selección de revistas extranjeras, y se analizó la producción en relación a volumen global, región geográfica, sector institucional (universidades públicas y privadas, centros independientes, organismos internacionales, etc.), área disciplinaria y autores. En base a ese análisis, se discuten los niveles de consolidación de la producción y difusión que revela el volumen de publicaciones existente, en general y por áreas disciplinarias; el peso de distintos tipos de instituciones; y las diferencias que existen entre la producción en revistas nacionales, extranjeras y librosFil: Tello, César. Universidad Nacional de La Plata. Facultad de Humanidades y Ciencias de la Educación; Argentina

Circumnuclear Keplerian Disks in Galaxies

In this paper we demonstrate the possibility of inferring the presence of Keplerian gaseous disks using optical ground-based telescopes properly equipped. We have modeled the peculiar bidimensional shape of the emission lines in a sample of five S0-Sa galaxies as due to the motion of a gaseous disk rotating in the combined potential of a central point-like mass and of an extended stellar disk. The value of the central mass concentration estimated for four galaxies of the sample (NGC 2179, NGC 4343, NGC 4435 and NGC 4459) is ~10^9 Msolar. For the remaining galaxy NGC 5064 an upper limit of 5*10^7 Msolar is estimated.Comment: 11 pages, LaTeX, with 3 PostScript figures, Submitted to The Astrophysical Journal Letter

Mixed Early and Late-Type Properties in the Bar of NGC 6221: Evidence for Evolution along the Hubble Sequence?

Rotation curves and velocity dispersion profiles are presented for both the stellar and gaseous components along five different position angles (P.A.=5, 50, 95, 125 and 155 degrees) of the nearby barred spiral NGC 6221. The observed kinematics extends out to about 80" from the nucleus. Narrow and broad-band imaging is also presented. The radial profiles of the fluxes ratio [NII]/Halpha reveal the presence of a ring-like structure of ionized gas, with a radius of about 9" and a deprojected circular velocity of about 280 km/s. The analysis of the dynamics of the bar indicates this ring is related to the presence of an inner Lindblad resonance (ILR) at 1.3 kpc. NGC6221 is found to exhibit intermediate properties between those of the early-type barred galaxies: the presence of a gaseous ring at an ILR, the bar edge located between the ILR's and the corotation radius beyond the steep rising portion of the rotation curve, the dust-lane pattern, and those of the late-type galaxies: an almost exponential surface brightness profile, the presence of Halpha regions along all the bar, the spiral-arm pattern. It is consistent with scenarios of bar-induced evolution from later to earlier-type galaxies.Comment: 1 File ds7406.tar.gz which contains: one latex file (ds7406.tex), and 10 encsulated postscript figures (ds7406f**.eps). To be compiled with aa-l latex2e macro style. To be published in A&A Sup. Serie

Economic Methodology for Pasture Grass and Legume Seed Production

The importance and complexity of the industrial process of seed production is known. Thus, conditions should be established for achieving and efficiently controlling the activity in order to know production costs, selling prices and to guarantee economic efficiency. The objective of this paper was to evaluate from an economic point of view, seed production of species of tropical grasses and legumes based on a preliminary methodology facilitating the control of the whole activity