Smallholders' Cost Efficiency in Mozambique: Implications for Improved Maize Seed Adoption

Maize is an important staple in Mozambique. It is also a dominant crop produced by smallholder farmers. However, the actual maize yields, currently estimated at 1.4 tons/ha, fall short of potential yields of 5-6.5 tons/ha. With population growth rate increasingly exceeding agricultural (and maize) productivity growth rate, the government of Mozambique faces a serious problem of food insecurity and poverty alleviation. This study examines cost inefficiency among smallholder maize farmers in Mozambique, and the impact of improved maize seed adoption on cost efficiency. A Translog functional form is used to estimate the frontier cost function. A cost-inefficiency function is used to examine the factors that determine cost inefficiency among farmers. Econometric techniques to control for self-selection bias resulting from endogeneity of the adoption variable are used.stochastic frontier, technology adoption, selection bias, Mozambique, Crop Production/Industries, Q12, Q16, D13, O33,

Smallholders’ Cost Efficiency in Mozambique: Implications for Improved Maize Seed Adoption

The objectives of this paper are to estimate cost efficiency and investigate factors influencing the cost efficiency of maize-growing smallholders in Mozambique. The data used in this study came from a national random sample of 4,908 smallholder farmers conducted by the Ministry of Agriculture and Rural Development in 2002. Stochastic cost frontier and self-selection bias methods are used. The results indicate that twelve out of twenty factors are significantly found to be the determining factors influencing the cost efficiency. To enhance the cost efficiency of producing maize, policy makers should put more emphasis on improving rural infrastructures, providing better education, and providing access to credit.Crop Production/Industries, Farm Management,

Adoption of Improved Maize Seed by Smallholder Farmers in Mozambique

The objective of this paper is to investigate factors influencing the adoption of improved maize seed by smallholder farmers in Mozambique. The data used in this study were obtained from a national random sample of 4,908 smallholder farmers conducted by the Ministry of Agriculture and Rural Development in 2002. Using Probit and Logit models, the main factors influencing adoption of improved maize seed were identified. The results of this analysis indicate that fifteen out of twenty five factors are significantly found to be the determining factors influencing the probability of adopting improved maize seed. To increase the likelihood of adopting improved maize seed, policy makers should put more emphasis on improving rural infrastructures and providing better education.Crop Production/Industries,

Proper Motions of H-alpha filaments in the Supernova Remnant RCW 86

We present a proper motion study of the eastern shock-region of the supernova remnant RCW 86 (MSH 14-63, G315.4-2.3), based on optical observations carried out with VLT/FORS2 in 2007 and 2010. For both the northeastern and southeastern regions, we measure an average proper motion of H-alpha filaments of 0.10 +/- 0.02 arcsec/yr, corresponding to 1200 +/- 200 km/s at 2.5kpc. There is substantial variation in the derived proper motions, indicating shock velocities ranging from just below 700 km/s to above 2200 km/s. The optical proper motion is lower than the previously measured X-ray proper motion of northeastern region. The new measurements are consistent with the previously measured proton temperature of 2.3 +/- 0.3 keV, assuming no cosmic-ray acceleration. However, within the uncertainties, moderately efficient (< 27 per cent) shock acceleration is still possible. The combination of optical proper motion and proton temperature rule out the possibility that RCW 86 has a distance less than 1.5kpc. The similarity of the proper motions in the northeast and southeast is peculiar, given the different densities and X-ray emission properties of the regions. The northeastern region has lower densities and the X-ray emission is synchrotron dominated, suggesting that the shock velocities should be higher than in the southeastern, thermal X-ray dominated, region. A possible solution is that the H-alpha emitting filaments are biased toward denser regions, with lower shock velocities. Alternatively, in the northeast the shock velocity may have decreased rapidly during the past 200yr, and the X-ray synchrotron emission is an afterglow from a period when the shock velocity was higher.Comment: Accepted for publication in MNRA

The influence of chain orientation in the electric behaviour of polymer diodes

Recently some experimental results have showed that the spatial alignment of conjugated polymer chains on nanometre length scales can influence the behaviour of polymer-based electronic devices, such as light-emitting diodes, field effect transistors, and photovoltaic cells. The effects of chain orientation at electrode-polymer interfaces on the charge injection process and charge mobility through the polymer layer are not well understood. In this work we use a generalized dynamical Monte Carlo method to study the influence of different polymer chain orientation relative to the electrodes surface on the electric behaviour of single-layer polymer diode, namely density current and charge density.Fundação para a Ciência e a Tecnologia (FCT) - POCTI/CTM/41574/2001; CONC-REEQ/443/EEI/2005; SFRH/BD/22143/2005FEDE

Computer simulation of hole distribution in polymeric materials

Polymers have been known for their flexibility and easy processing into coatings and films, which made them suitable to be applied in a variety of areas and in particular the growing area of organic electronics. The electronic properties of semiconducting polymers made them a serious rival in areas where until now inorganic materials were the most used, such as light emitting diodes or solar cells. Typical polymers can be seen as a network of molecular strands of varied lengths and orientations, with a random distribution of physical and chemical defects which makes them an anisotropic material. To further increase their performance, a better understanding of all aspects related to charge transport and space charge distribution in polymeric materials is required. The process associated with charge transport depends on the properties of the polymer molecules as well as connectivity and texture, and so we adopt a mesoscopic approach to build polymer structures. Changing the potential barrier for charge injection we can introduce holes in the polymer network and, by using a generalised Monte-Carlo method, we can simulate the transport of the injected charge through the polymer layer caused by imposing a voltage between two planar electrodes. Our results show that the way that holes distribute within polymer layer and charge localization in these materials is quite different from the inorganic ones.Fundação para a Ciência e a Tecnologia (FCT) – Programa Operacional “Ciência, Tecnologia, Inovação” – POCTI/CTM/41574/2001, CONC-REEQ/443/EEI/2005, SFRH/BD/22143/2005European Community Fund (FEDER

Mesoscopic modelling of polymer-based optoelectronic devices

Substantial progress has been made in fabricating optoelectronic devices using polymers as an active material. In polymer light emitting diodes (PLEDs), a balanced injection of electrons and holes from the electrodes is fundamental to increase their performance. Using a mesoscopic model based on a generalized Monte-Carlo method, we studied the influence of changing zero-field barrier heights at both electrode/polymer interfaces in the performance of a PLED with an active layer of poly paraphenylenevinylene) (PPV). Our results show that by controlling the electrodes work functions it is possible to tune the region inside the device where charge recombination preferentially takes place.Fundação para a Ciência e a Tecnologia (FCT) Programa Operacional “Ciência , Tecnologia, Inovação” – POCTI/CTM/41574/2001, CONC-REEQ/443/EEI/2001 e SFRH/BD/22143/200

Adoption of Improved Maize Seed by Smallholder Farmers in Mozambique

The objective of this paper is to investigate factors influencing the adoption of improved maize seed by smallholder farmers in Mozambique. The data used in this study were obtained from a national random sample of 4,908 smallholder farmers conducted by the Ministry of Agriculture and Rural Development in 2002. Using Probit and Logit models, the main factors influencing adoption of improved maize seed were identified. The results of this analysis indicate that fifteen out of twenty five factors are significantly found to be the determining factors influencing the probability of adopting improved maize seed. To increase the likelihood of adopting improved maize seed, policy makers should put more emphasis on improving rural infrastructures and providing better education

Chandra observations of SN 1987A: the soft X-ray light curve revisited

We report on the present stage of SN 1987A as observed by the Chandra X-ray Observatory. We reanalyze published Chandra observations and add three more epochs of Chandra data to get a consistent picture of the evolution of the X-ray fluxes in several energy bands. We discuss the implications of several calibration issues for Chandra data. Using the most recent Chandra calibration files, we find that the 0.5-2.0 keV band fluxes of SN 1987A have increased by ~6 x 10 ^-13 erg s^-1 cm^-2 per year since 2009. This is in contrast with our previous result that the 0.5-2.0 keV light curve showed a sudden flattening in 2009. Based on our new analysis, we conclude that the forward shock is still in full interaction with the equatorial ring.Comment: Accepted for publication by ApJ, 7 pages, 5 figure

The kinematics and chemical stratification of the Type Ia supernova remnant 0519-69.0

We present an analysis of the XMM-Newton and Chandra X-ray data of the young Type Ia supernova remnant 0519-69.0 in the Large Magellanic Cloud. We used data from both the Chandra ACIS and XMM-Newton EPIC-MOS instruments, and high resolution X-ray spectra obtained with the XMM-Newton Reflection Grating Spectrometer. The Chandra data show that there is a radial stratification of oxygen, intermediate mass elements and iron, with the emission from more massive elements more toward the center. Using a deprojection technique we measure a forward shock radius of 4.0(3) pc and a reverse shock radius of 2.7(4) pc. We took the observed stratification of the shocked ejecta into account in the modeling of the X-ray spectra with multi-component NEI models, with the components corresponding to layers dominated by one or two elements. An additional component was added in order to represent the ISM, which mostly contributed to the continuum emission. This model fits the data well, and was also employed to characterize the spectra of distinct regions extracted from the Chandra data. From our spectral analysis we find that the fractional masses of shocked ejecta for the most abundant elements are: M(O)=32%, M(Si/S)=7%/5%, M(Ar+Ca)=1%, and M(Fe) = 55%. From the continuum component we derive a circumstellar density of nH= 2.4(2)/cm^3. This density, together with the measurements of the forward and reverse shock radii suggest an age of 450+/-200 yr,somewhat lower than, but consistent with the estimate based on the optical light echo (600+/-200 yr). From the RGS spectra we measured a Doppler broadening of sigma=1873+/-50 km/s, from implying a forward shock velocity of vS = 2770+/-500 km/s. We discuss the results in the context of single degenerate explosion models, using semi-analytical and numerical modeling, and compare the characteristics of 0519-69.0 with those of other Type Ia supernova remnants.Comment: Astronomy and Astrophysics in press. This version is the A&A accepted version, which contains improved figures and an extended discussion sectio