5,734 research outputs found
Energy consumption in the US reconsidered. Evidence across sources and economic sectors
This study analyzes the impact of GDP shocks in USA on primary energy consumption and the reverse impact in a comprehensive and novel framework, distinguishing by economic sectors (commercial, industrial, residential and transportation) and energy source, i.e., total fossil (coal, natural gas and petroleum), nuclear, and renewable (hydroelectric, geothermal and biomass) for the period 1973:1 to 2015:2. To this end, we apply Granger causality analysis through the Hatemi-J [1] and Toda and Yamamoto [2] approaches from a time series perspective to evaluate the existence of asymmetries on this bidirectional relationship. The empirical results suggest that the impact of GDP on primary energy consumption is heterogeneous and energy source-specific, and an asymmetric behavior appears among cycles. Moreover, it seems clear that the US economy is highly dependent on petroleum energy consumption. The renewable energy sources do not seem to show any relationshipsources seem to show no relationship with economic growth, and finally, our results suggest that energy consumption in the industrial sector is key to economic growth and is also very sensitive to negative economic shocks
The Anthropomorphic Hand Assessment Protocol (AHAP)
The progress in the development of anthropomorphic hands for robotic and prosthetic applications has not been followed by a parallel development of objective methods to evaluate their performance. The need for benchmarking in grasping research has been recognized by the robotics community as an important topic. In this study we present the Anthropomorphic Hand Assessment Protocol (AHAP) to address this need by providing a measure for quantifying the grasping ability of artificial hands and comparing hand designs. To this end, the AHAP uses 25 objects from the publicly available Yale-CMU-Berkeley Object and Model Set thereby enabling replicability. It is composed of 26 postures/tasks involving grasping with the eight most relevant human grasp types and two non-grasping postures. The AHAP allows to quantify the anthropomorphism and functionality of artificial hands through a numerical Grasping Ability Score (GAS). The AHAP was tested with different hands, the first version of the hand of the humanoid robot ARMAR-6 with three different configurations resulting from attachment of pads to fingertips and palm as well as the two versions of the KIT Prosthetic Hand. The benchmark was used to demonstrate the improvements of these hands in aspects like the grasping surface, the grasp force and the finger kinematics. The reliability, consistency and responsiveness of the benchmark have been statistically analyzed, indicating that the AHAP is a powerful tool for evaluating and comparing different artificial hand designs
John Brown University disaster shelter competition
John Brown University hosted the 6th annual Disaster Shelter Relief Competition in April 2017 for which the team built a prototype shelter and proposed a camp plan. Both the shelter and the camp plan were designed to house refugees coming into Greece from the Middle East. The shelter would accommodate a family of four and the camp plan was designed to hold 1250 shelters, or 5000 people. The shelter was built on site at John Brown University and was required to take less than two hours to fully construct. This report summarizes the work the team did for the competition, including a review of existing shelter designs currently in use, a description of the method of design of the prototype, validation that the prototype meets the criteria, a discussion of the cultural appropriateness of the shelter to the scenario, suggested modifications and improvements that can be made, photos and drawings of the prototype, and the camp plan
Selection of antagonistic actinomycete isolates as biocontrol agents against root-rot fungi
In this study, actinomycetes isolates, isolated from rhizosphere of wheat (Triticum aestivum L.), were screened for antagonistic activities on certain root rot fungi (Fusarium culmorum, Fusarium graminearum, Fusarium verticilloides and Bipolaris sorokiniana). The in vitro antagonistic effects of actinomycetes isolates were determined on solid media against fungal pathogens. The inhibition mechanism, effect of application time and pH on inhibition was investigated. The actinomycete isolate 129.01 exhibited a high inhibition ratio of more than 60 % against all fungi. The activity of the isolate 129.01 against root rot fungi was tested under greenhouse conditions. The root rot score (1-10), mean plant height (cm) and mean weight of green part of plant (g) were determined after an incubation period. The root rot score of the infected plants was decreased significantly by this isolate, even if the plants were inoculated with all of the pathogen fungi together (P<0.05). The results indicate that isolate 129.01 could be useful as a biocontrol agent. The assignment of the isolate 129.01 to the genus Streptomyces was supported by 16S rRNA analysis.Fil: Erginbas, Gul. Centro Internacional de Mejoramiento de Maíz y Trigo; TurquíaFil: Yamac, Mustafa. Eskisehir Osmangazi University; TurquíaFil: Amoroso, Maria Julia del R.. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Planta Piloto de Procesos Industriales Microbiológicos; ArgentinaFil: Cuozzo, Sergio Antonio. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Planta Piloto de Procesos Industriales Microbiológicos; Argentin
First Order Actions and Duality
We consider some aspects of classical S-duality transformations in first
order actions taken into account the general covariance of the Dirac algorithm
and the transformation properties of the Dirac bracket. By classical S-Duality
transformations we mean a field redefinition that interchanges the equations of
motion and its associated Bianchi identities. By working from a first order
variational principle and performing the corresponding Dirac analysis we find
that the standard electro-magnetic duality can be reformulated as a canonical
local transformation. The reduction from this phase space to the original phase
space variables coincides with the well known result about duality as a
canonical non local transformation. We have also applied our ideas to the
bosonic string. These Dualities are not canonical transformations for the Dirac
bracket and relate actions with different kinetic terms in the reduced space.Comment: accepted for publication in IJMP
Closed model structures for algebraic models of n-types
AbstractIn this paper we give a general method to obtain a closed model structure, in the sense of Quillen, on a category related to the category of simplicial groups by a suitable adjoint situation. Applying this method, categories of algebraic models of connected types such as those of crossed modules of groups (2-types), 2-crossed modules of groups (3-types) or, in general, n-hypercrossed complexes of groups ((n + l)-types), as well as that of n-simplicial groups (all types), inherit such a closed model structure
Persiana modulable de doble recorrido.
Article about comparative study of modulable shutters versus traditional shutters: hypothesis, methodology, analysis and conclusions
Estrategia didáctica para un aprendizaje significativo en la enseñanza de los números enteros en los séptimos grados, del Instituto Nacional Juan XIII en el Municipio de San Marcos, Carazo
Este trabajo final presenta una estrategia didáctica aplicada para la enseñanza de los números enteros en los séptimos grados, realizado en el Instituto Nacional Juan XIII, en la Ciudad de San Marcos, Carazo. Se utilizó estrategia didáctica a modo de juegos y actividades, en el que se puede aprender a realizar operaciones básicas con números enteros.
Las experiencias en el aula de clase muestran que los números enteros, es un eje muy importante en el conocimiento de la matemática, es por esto que esta propuesta de trabajo busca apoyar el proceso de enseñanza aprendizaje de los estudiantes de los séptimos grados, para ello se toma el constructivismo como una forma de apoyar este trabajo.
Para cumplir con este objetivo se inicia con la elaboración de diferentes instrumentos que permitan al docente ver la concepción que tiene el estudiante de los conceptos de los números positivos, negativos y solución de ejercicios, luego se propone iniciar una transcripción del lenguaje cotidiano al simbolismo matemático.
Se compararon los resultados obtenidos del grupo seleccionado al azar de estudiantes al cual se le aplicó una estrategia didácticas basadas en actividades sencillas como juegos y resolución de problemas. Los resultados muestran un alto grado de motivación hacia el aprendizaje en los estudiantes que participaron en la estrategia didáctica aplicada
Characterization of Rhizobium grahamii extrachromosomal replicons and their transfer among rhizobia
Background Rhizobium grahamii belongs to a new phylogenetic group of rhizobia together with Rhizobium mesoamericanum and other species. R. grahamii has a broad-host-range that includes Leucaena leucocephala and Phaseolus vulgaris, although it is a poor competitor for P. vulgaris nodulation in the presence of Rhizobium etli or Rhizobium phaseoli strains. This work analyzed the genome sequence and transfer properties of R. grahamii plasmids. Results Genome sequence was obtained from R. grahamii CCGE502 type strain isolated from Dalea leporina in Mexico. The CCGE502 genome comprises one chromosome and two extrachromosomal replicons (ERs), pRgrCCGE502a and pRgrCCGE502b. Additionally, a plasmid integrated in the CCGE502 chromosome was found. The genomic comparison of ERs from this group showed that gene content is more variable than average nucleotide identity (ANI). Well conserved nod and nif genes were found in R. grahamii and R. mesoamericanum with some differences. R. phaseoli Ch24-10 genes expressed in bacterial cells in roots were found to be conserved in pRgrCCGE502b. Regarding conjugative transfer we were unable to transfer the R. grahamii CCGE502 symbiotic plasmid and its megaplasmid to other rhizobial hosts but we could transfer the symbiotic plasmid to Agrobacterium tumefaciens with transfer dependent on homoserine lactones. Conclusion Variable degrees of nucleotide identity and gene content conservation were found among the different R. grahamii CCGE502 replicons in comparison to R. mesoamericanum genomes. The extrachromosomal replicons from R. grahamii were more similar to those found in phylogenetically related Rhizobium species. However, limited similarities of R. grahamii CCGE502 symbiotic plasmid and megaplasmid were observed in other more distant Rhizobium species. The set of conserved genes in R. grahamii comprises some of those that are highly expressed in R. phaseoli on plant roots, suggesting that they play an important role in root colonization.Fil: Althabegoiti, Maria Julia. Universidad Nacional Autónoma de México; México. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Ormeño Orrillo, Ernesto. Universidad Nacional Autónoma de México; MéxicoFil: Lozano, Luis. Universidad Nacional Autónoma de México; MéxicoFil: Torres Tejerizo, Gonzalo Arturo. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional Autónoma de México; MéxicoFil: Rogel, Marco Antonio. Universidad Nacional Autónoma de México; MéxicoFil: Mora, Jaime. Universidad Nacional Autónoma de México; MéxicoFil: Martinez Romero, Esperanza. Universidad Nacional Autónoma de México; Méxic
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