Impact of Technological Change on Developing Countries, The

The Impact of Technological Change in the Canada/U.S. Contex

Impact of Technological Change on Developing Countries, The

The Impact of Technological Change in the Canada/U.S. Contex

Anderson localization in carbon nanotubes: defect density and temperature effects

The role of irradiation induced defects and temperature in the conducting properties of single-walled (10,10) carbon nanotubes has been analyzed by means of a first-principles approach. We find that di-vacancies modify strongly the energy dependence of the differential conductance, reducing also the number of contributing channels from two (ideal) to one. A small number of di-vacancies (5-9) brings up strong Anderson localization effects and a seemly universal curve for the resistance as a function of the number of defects. It is also shown that low temperatures, around 15-65 K, are enough to smooth out the fluctuations of the conductance without destroying the exponential dependence of the resistivity as a function of the tube length.Comment: 4 pages, 4 figure

Visioning a Sustainable Energy Future: The Case of Urban Food-Growing

We outline a future where society re-energises itself, in the sense both of recapturing creative dynamism, and of applying creativity to meeting physical energy needs. Both require us to embrace self-organising properties, whether in nature or society. We critically appraise backcasting as a methodology for visioning, arguing that backcasting’s potential for radical, outside-the-box thinking is restricted unless it contemplates a break with class society, connects with existing grassroots struggles (notably over land) and dialogues with utopian socialist tradition. We develop a case study of food, starting from the physical parameters of combatting the entropy expressed in the loss of soil structure, and apply this to urban food-growing. Drawing upon ‘real utopias’ of existing practice, the paper proposes a threefold categorisation: subsistence plots, an urban forest, and an ultra-high productivity sector. We emphasise the emergent properties of such a complex system characterised by the ‘free energy’ of societal self-organisation

The cDNA and deduced amino acid sequence of the γ subunit of the L-type calcium channel from rabbit skeletal muscle

Complementary DNAs for the γ subunit of the calcium channel of rabbit skeletal muscle were isolated on the basis of peptide sequences derived from the purified protein. The deduced primary structure is without homology to other known protein sequences and is consistent with the γ subunit being an integral membrane protein

Nonperturbative indirect exchange in spin valley coupled two-dimensional crystals

We study indirect exchange interactions between localized spins of magnetic impurities in spin valley coupled systems described with the Kane-Mele model. Our model captures the main ingredients of the energy bands of the 1H transition metal dichalcogenide (TMD) monolayers, such as 1H-MoS2 and 1H-NbSe2. To obtain the effective interactions, we use the exact diagonalization of the Hamiltonian, avoiding momentum cutoffs. We start by comparing the standard perturbation expansion in terms of the Kondo exchange with the exact calculation of the interaction, treating the local spins classically. We find that perturbation theory works well even beyond the regime where the relevant figure of merit, the ratio between the exchange J and the hopping t, is small. We verify that the effective indirect exchange Hamiltonian derived from perturbation theory also works in the nonperturbative regime. Additionally, we analyze the interplay between the symmetry of the different terms of the interaction (Heisenberg, Ising, and Dzyaloshinskii-Moriya), the Fermi-surface topology, and the crystallographic direction in which the impurities are placed. We show that the indirect exchange along the armchair direction is actually Heisenberg-like, due to the reflection symmetry of the crystal structure around this direction. Finally, we explore the exploitation of indirect exchange, combined with atomic manipulation, to engineer the Majumdar-Ghosh model. Our results show that TMDs provide an extremely versatile platform to engineer indirect exchange interactions.This study forms part of the Advanced Materials programme and was supported by MCIN with funding from European Union NextGenerationEU (PRTR-C17.I1) and by Generalitat Valenciana (MFA/2022/045). We acknowledge Programa Operativo FEDER/Junta de Andalucía—Consejería de Transformación Económica, Industria, Conocimiento, y Universidades (Grant No. P18-FR-4834). The Albaicín supercomputer of the University of Granada is also acknowledged for providing computational time and facilities. B.B. acknowledges financial support from AEI under Project No. PID2021-125604NB-I00. J.F.R. acknowledges financial support from FCT (Grant No. PTDC/FIS-MAC/2045/2021), SNF Sinergia (Grant Pimag), Generalitat Valenciana funding Prometeo 2021/017 and MFA/2022/045, and funding from MICIIN-Spain (Grant No. PID2019-109539GB-C41)

Spatial variability in the soil water content of a Mediterranean agroforestry system with high soil heterogeneity

Variability of soil water content is known to increase with the size of spatial domain in which measurements are taken. At field scale, heterogeneity in soil, vegetation, topography, water input volume and management affects, among other factors, hydrologic plot behaviour under different mean soil water contents. The present work studies how the spatial variability of soil water content (SWC) is affected by soil type (texture, percentage of stones and the combination of them) in a timber-orientated plantation of cherry tree (Prunus avium) under Mediterranean climatic conditions. The experimental design is a randomized block one with 3 blocks * 4 treatments, based on two factors: irrigation (6 plots irrigated versus 6 plots not irrigated) and soil management (6 plots tillaged versus 6 plots not tillaged). SWC is continuously measured at 25, 50 and 100 cm depth with FDR sensors, located at two positions in each treatment: under tree influence and 2.5 m apart. This study presents the results of the monitoring during 2012 of the 24 sensors located at the 25 cm depth. In each of the measurement point, texture and percentage of stones were measured. Sandy-loam, sandy-clay-loam and loam textures were found together with a percentage of stones ranging from 20 to 70 %. The results indicated that the relationship between the daily mean SWC and its standard deviation, a common procedure used to study spatial variability, changed with texture, percentage of stones and the estimation of field capacity from the combination of both. Temporal stability analysis of SWC showed a clear pattern related to field capacity, with the measurement points of the sandy-loam texture and the high percentage of stones showing the maximun negative diference with the global mean. The high range in the mean relative difference observed ( 75 %), could indicate that the studied plot may be considered as a good field-laboratory to extrapolate results at higher spatial scales. Furthermore, the pattern in the temporal stability of tree growth was clearly related to that one in SWC. Nevertheless, the treatments that represent the mean conditions in growth were not exactly the same than those in SWC, which could be attributable to other characteristics than soil

Controles oficiales de calidad y lucha contra el fraude en el sector del aceite de oliva en Cataluña. Resultados 2011–2014

This article highlights the key aspects of the official control procedures concerning quality and in the fight against food fraud in the oil sector implemented in Catalonia by the Ministry for Agriculture, Livestock, Fisheries and Food of the Government of Catalonia and, more specifically, by the Subdirectorate General of Agri-food Inspection and Control. This summarized view focuses on issues related to the legality and competence framework for official controls, the goals and purpose thereof, the area’s object of investigation and technical scope, the stages of the food chain at which measures are carried out, the types of inspection and control actions and the main investigation techniques. It also presents the results of the inspections, with a summary of the types of irregularities detected in the olive oil sector over the 2011–2014 period.En este artículo se exponen los aspectos más relevantes del control oficial en materia de calidad y lucha contra el fraude alimentario en el sector del aceite, efectuado en Cataluña por el Departamento de Agricultura, Ganadería, Pesca y Alimentación de la Generalitat de Catalunya, y en concreto, por la Subdirección General de la Inspección y Control Agroalimentario. De manera resumida se focaliza en los aspectos relacionados con el marco legal y competencial del control oficial, objetivo y finalidad del control oficial, ámbitos objeto de investigación y alcance técnico, fase de la cadena alimenticia donde se realiza, tipo de actuaciones de inspección y control y principales técnicas de investigación. Asimismo, se presentan los resultados de las inspecciones, con un resumen de los tipos de irregularidades detectadas en el sector del aceite de oliva en el período 2011–2014