Cross-country differences in monetary policy transmission

This paper examines possible explanations for observed differences in the transmission of euro area monetary policy in central bank large-scale macroeconomic models. In particular it considers the extent to which these differences are due to differences in the underlying economies or (possibly unrelated) differences in the modelling strategies adopted for each country. It finds that, against most yardsticks, the cross-country variations in the results are found to be plausible in the sense that they correspond with other evidence or observed characteristics of the economies in question. Nevertheless, the role of differing modelling strategies may also play a role. Important features of the models –for instance in the treatment of expectations or wealth– can have a major bearing on the results that may not necessarily reflect differences in the underlying economies.[resumen de autor

Hybrid poly(ether ether ketone) composites reinforced with a combination of carbon fibres and graphene nanoplatelets

Poly(ether ether ketone) (PEEK), with its superb mechanical properties, excellent chemical resistance and high thermo-oxidative stability is one of the most important engineering thermoplastics for high-end applications. In this work, we investigate the elastic and viscoelastic properties along with the creep mitigation of two sets of samples: PEEK reinforced with graphene nanoplatelets (GNPs) and PEEK reinforced with a hybrid graphene/short carbon fibre (CF) filler. The melt viscosity of the PEEK nanocomposites was found to increase with increasing GNPs content; however, the viscosity of the hybrid CF-GNP samples with the highest filler content was equal to the one of the samples filled only with GNPs at low shear rates. This processability shows the advantage of GNPs over other nano and conventional fillers in the ability to use meaningful loadings. The introduction of GNPs improved significantly the stiffness and the storage modulus of the materials in both PEEK-GNP and PEEK-CF-GNP composites. Moreover, the presence of GNPs within the composites led to a restriction of the mobility of the macromolecular chains of PEEK, which resulted in enhanced creep properties at both room temperature and elevated temperatures. Overall, the nanocomposites produced displayed properties that make them attractive in applications where high stiffness and structural integrity at elevated temperatures are required

Coulomb Zero-Bias Anomaly: A Semiclassical Calculation

Effective action is proposed for the problem of Coulomb blocking of tunneling. The approach is well suited to deal with the ``strong coupling'' situation near zero bias, where perturbation theory diverges. By a semiclassical treatment, we reduce the physics to that of electrodynamics in imaginary time, and express the anomaly through exact conductivity of the system $\sigma(\omega, q)$ and exact interaction. For the diffusive anomaly, we compare the result with the perturbation theory of Altshuler, Aronov, and Lee. For the metal-insulator transition we derive exact relation of the anomaly and critical exponent of conductivity.Comment: 9 pages, RevTeX 3.

The mechanics of reinforcement of polymers by graphene nanoplatelets

A detailed study has been undertaken of the mechanisms of stress transfer in polymeric matrices with different values of Young's modulus, Em, reinforced by graphene nanoplatelets (GNPs). For each material, the Young's modulus of the graphene filler, Ef, has been determined using the rule of mixtures and it is found to scale with the value of Em. Additionally stress-induced Raman bands shifts for the different polymer matrices show different levels of stress transfer from the polymer matrix to the GNPs, which again scale with Em. A theory has been developed to predict the stiffness of the bulk nanocomposites from the mechanics of stress transfer from the matrix to the GNP reinforcement based upon the shear-lag deformation of individual graphene nanoplatelets. Overall it is found that it is only possible to realise the theoretical Young's modulus of graphene of 1.05 TPa for discontinuous nanoplatelets as Em approaches 1 TPa; the effective modulus of the reinforcement will always be less for lower values of Em. For flexible polymeric matrices the level of reinforcement is independent of the graphene Young's modulus and, in general, the best reinforcement will be obtained in nanocomposites with strong graphene-polymer interfaces and aligned nanoplatelets with high aspect ratios

TPM Maintenance Management Model Focused on Reliability that Enables the Increase of the Availability of Heavy Equipment in the Construction Sector

The purpose of this paper is to present a maintenance study focused on total productive maintenance (TPM) and reliability-centered maintenance (RCM). Its approach is based on the first pillars of TPM, preventive and autonomous maintenance, as well as the FMEA analysis of RCM for maintenance analysis, which was conducted in this study. The implementation of TPM was successful in that various preventive maintenance (PM) policies assigned to the assets were implemented and it was demonstrated that TPM application in the construction industry could reduce the excessive accumulation of maintenance with the same effective optimization, and with support from RCM analysis and its heavy equipment systems analysis. Excessive corrective maintenance accounts for high investment and delay rates in work times of the assigned project. Traditional methods of availability guarantee, such as reactive or routine maintenance, are insufficient to satisfy a heavy equipment maintenance plan; therefore, what is called for is the systematic application of RCM and TMP because they allow the selection and application of effective PM tasks. An approach that develops and thoroughly analyzes the strategies of continuous corrective and PM is used with an atmosphere of uncertainty and with operational data limited by criticism. Results show a 90% improvement in availability.Revisión por pare

Efecto garrapaticida del Bromophos ethylico.

Se describe el efecto garrapaticida de un compuesto fosforado de acción sistémica. El trabajo se realiza en la Estación Experimental El Nus, en Antioquia, Colombia. Se utilizan 30 hembras adultas de la raza Blaco Orejinegro repartidas en 3 grupos (1, 2, 3) de 10 animales cada uno. La droga usada fue el Bromophus Ethylico en baños por aspersión en concentraciones de 1:2000 y 1:1000 para los grupos 1 y 2 respectivamente, el grupo 3, control, fue bañado por inmersión en Matatik. El experimento se divide en 2 partes. La primera parte con 12 recuentos de garrapatas y 3 tratamientos para todos los animales, durante 112 días. Para la segunda parte los grupos 1 y 2 se dividen en 2 subgrupos de 5 animales cada uno, designando 1A y 2A los subgrupos tratados y 1B y 2B los subgrupos no tratados. La mejor efectividad del Bromophos Ethylico se observó a la concentración de 1:1000. La concentración 1:2000 ejerce un buen control sobre las garrapatas, aunque su período de acción residual es más corto. A las concentraciones usadas no se observó ningún síntoma tóxico. Además, no se observó efecto insecticida sobre ningún estado larvario de Dermatobia hominis en lo que respecta a las concentraciones usadas en el experiment

The relationship between aerobic fitness and depression level determined with Hamilton scale in older adults

INTRODUCTION: Depression is a major public health problem associated with both morbidity and mortality throughout the world, in Mexico epidemiological reports show a prevalence of depression in older adults of 9.5% in women and 5% in men; it is widely held that regular exercise and physical activity in older subjects have a significant impact on psychological health and well-being. PURPOSE: To determine whether if higher aerobic fitness is associated with decreased symptoms of clinical depression in older adults. METHODS: Participants (n=21) included individuals raging ages from 61 to 72 years old and were not regular exercisers. The 6 minute walking test was used to determine the aerobic fitness, the total distance covered during the test was determined with pedometers; all subjects were free of unstable cardiovascular symptoms and disabilities that could interfere with performance in the sub-maximal exercise test. Indirect Peak Oxygen Consumption (VO2peak) was obtained with the equation stablished by Burr et al. (2011). Depression Symptoms were evaluated using the Hamilton Depression Scale which consisted of an interview of the subjects and scoring 17 items defined in terms of a series of categories of increasing intensity. Statistical analyses included a non-parametric Spearman correlation test to determine the association between predicted VO2peak and depression, level of significance was stablished at P≤0.05. RESULTS: Twenty one overweight (BMI 29.3±3.7 kg/m2) subjects that presented mild clinical depression symptoms were included in the study. A moderate negative correlation between predicted peak VO2 and depression was obtained, with a coefficient of r= -0.5099 (P≤0.05). A regression analysis was performed to establish the significant predictor of VO2 entering the analysis a psychological variable as a dependent factor (P value 0.0102). CONCLUSION: Based on the results, there is evidence that aerobic exercise could be a plausible and healthy strategy to avert depressive symptoms in the appearance of clinical depression in older adults