13,704 research outputs found
A framework for analysing the adoption of New Zealand pastoral farming systems in central Veracruz State, Mexico : a thesis presented in partial fulfilment of the requirements for the degree of Master of Agricultural Science in Farm Management at Massey University
Tropical areas of developing countries have significant potential for increased food production. In the case of Mexico, an important economic activity in the tropics is livestock production based on pasture. Tropical regions represent 25% of the total area of Mexico and support more than 50% of the country's cow production. Historically, however, animal production in Mexican, and other tropical areas, has been low. Low pasture utilisation, and associated poor herbage quality, is one factor that contributes to poor animal performance in the tropics. This situation contrasts with the success of New Zealand pastoral systems, which in comparative terms have been able to obtain high levels of animal production and efficient use of pasture. Differences in pasture productivity (both in quality and quantity) and social and economic conditions between the Mexican tropics and New Zealand are large. Nevertheless it was proposed that some of the pastoral farming methods used in New Zealand, could be adapted to the conditions of tropical farmers in Mexico, particularly in relation to effective planning and control of the farming system. To test this hypothesis, the consequences of implementing some of New Zealand's pastoral farming techniques under tropical conditions in Central Veracruz State were explored by developing a spreadsheet model to simulate local farming systems. The model included linked submodels for pasture growth and quality, livestock transactions, milk production and enterprise gross margins. The effect of improved farming systems of milk output and cash returns were evaluated relative to the average levels of performance currently achieved from a medium-sized farm in the Central region of Veracruz State in Mexico. Straight forward changes in the design of the farming system, such as synchronising calving with the pattern of pasture growth rather than year-round calving, would significantly affect milk production and cash returns to the farm family. The modelling process was seriously constrained by the lack of farm-level data on pasture production and animal performance. Nevertheless, the model framework clearly identifies which data should be collected, and priority should now be given to assembling these data so simulation decision support models such as that developed in this study, can be effectively used to plan improved farming systems. Keywords: tropical agricultural, Mexico, farming systems, spreadsheet model
Spatial storage of discrete dark solitons
The interaction between a mobile discrete dark soliton (DDS) and impurities
in one-dimensional nonlinear (Kerr) photonic lattices is studied. We found that
the scattering is an inelastic process where the DDS can be reflected or
transmitted depending on its transversal speed and the strength of the
impurities. In particular, in the reflection regime, the DDS increases its
transversal speed after each scattering. A method for spatial storage of DDS
solutions using two impurities is discussed, where the soliton can be trapped
within a storage region until it reaches the critical speed needed to be
transmitted. We show, numerically, that this method allows the storage of
multiple DDS simultaneously.Comment: 6 pages and 6 figure
Classical Emergence of Intrinsic Spin-Orbit Interaction of Light at the Nanoscale
Traditionally, in macroscopic geometrical optics intrinsic polarization and
spatial degrees of freedom of light can be treated independently. However, at
the subwavelength scale these properties appear to be coupled together, giving
rise to the spin-orbit interaction (SOI) of light. In this work we address
theoretically the classical emergence of the optical SOI at the nanoscale. By
means of a full-vector analysis involving spherical vector waves we show that
the spin-orbit factorizability condition, accounting the mutual influence
between the amplitude (spin) and phase (orbit), is fulfilled only in the
far-field limit. On the other side, in the near-field region, an additional
relative phase introduces an extra term that hinders the factorization and
reveals an intricate dynamical behavior according to the SOI regime. As a
result, we find a suitable theoretical framework able to capture analytically
the main features of intrinsic SOI of light. Besides allowing for a better
understanding into the mechanism leading to its classical emergence at the
nanoscale, our approach may be useful in order to design experimental setups
that enhance the response of SOI-based effects.Comment: 10 pages, 5 figure
La co-educaciĂłn en el ámbito educativo : proyecto de intervenciĂłn interdisciplinar en la materia de educaciĂłn fĂsica
Treball Final de Mà ster Universitari en Igualtat i Gènere en l'Àmbit Públic i Privat (Pla de 2013). Codi: SRM042. Curs: 2015/2016La discriminación por motivos de género en el ámbito educativo es un reflejo de nuestra
sociedad y no se puede negar que sucede actualmente en nuestros centros educativos.
Nuestra herencia cultural procedente del androcentrismo considera el modelo masculino
como universal, quedando todavĂa resquicios y actitudes sexistas derivadas del mismo.
La materia de EducaciĂłn FĂsica no es una excepciĂłn ya que, a pesar de que ha ido
perdiendo parte de la carga sexista que poseĂa en sus orĂgenes, todavĂa podemos
percibir multitud de actitudes sexistas durante las clases de EducaciĂłn Secundaria
Obligatoria.
Uno de los errores que se han cometido en torno a este tema es considerar que la
escuela mixta garantizaba un trato igualitario al alumnado por el mero hecho de que
tanto los alumnos como las alumnas convivieran en una misma clase. Es por ello que la
coeducación en el ámbito educativo cobra especial importancia ya que ésta, además de
educar conjuntamente tanto a alumnos como alumnas, pretende crear las condiciones
necesarias para que se lleve a cabo una igualdad de oportunidades real a través del
respeto y atendiendo a las caracterĂsticas de ambos grupos.
Los objetivos principales de este TFM se resumen en, por un lado, conocer y analizar la
situación actual de todo lo comentado anteriormente y, por otro y en base a ello, diseñar
un proyecto de intervenciĂłn interdisciplinar para un centro de educaciĂłn secundaria
liderado desde la materia de EducaciĂłn FĂsica con el propĂłsito de aplicar una serie de
estrategias educativas y metodolĂłgicas apoyadas en los modelos globalizadores que
permitan modificar actitudes, prejuicios y estereotipos sociales para eliminar las
situaciones de desigualdad de género
Pricing Derivatives Securities with Prior Information on Long- Memory Volatility
This paper investigates the existence of long memory in the volatility of the Mexican stock market. We use a stochastic volatility (SV) model to derive statistical test for changes in volatility. In this case, estimation is carried out through the Kalman filter (KF) and the improved quasi-maximum likelihood (IQML). We also test for both persistence and long memory by using a long-memory stochastic volatility (LMSV) model, constructed by including an autoregressive fractionally integrated moving average (ARFIMA) process in a stochastic volatility scheme. Under this framework, we work up maximum likelihood spectral estimators and bootstraped confidence intervals. In the light of the empirical findings, we develop a Bayesian model for pricing derivative securities with prior information on long-memory volatility.contingent pricing, econometric modeling
The monkey’s smile: A satire by Herrera the Younger on knowledge in the Arts
Partiendo de una conocida anécdota literaria en la vida
de Herrera el Mozo por Palomino se ofrece un análisis
de la imagen satĂrica del mono cuyo significado remite
a los excesos de la imitaciĂłn servil y a la pintura como
ciencia especulativa capaz de reivindicarse en la risaFocusing on a well-kown literary anecdote in Palomino’s
life of Herrera the Younger, this article analyzes the satirical
image of the ape whose meaning refers to the excesses
of the servile imitation and claims for painting as an
speculative science that uses laughter to vindicate itsel
Silicon-photonics microwave oscillators closer to commercialisation
This project has received funding from the European Research Council (ERC) under the European Union's Horizon 2020 research and innovation programme under grant agreement No. 945915.MartĂnez, A. (2021). Silicon-photonics microwave oscillators closer to commercialisation. The Project Repository Journal. 12:20-23. https://doi.org/10.54050/PRJ121841020231
Analysis of ultra low cycle fatigue problems with the barcelona plastic damage model
This paper presents a plastic formulation based on the Barcelona plastic damage model ([1], [2]) capable of predicting the material failure due to Ultra Low Cycle Fatigue. This is achieved taking into account the fracture energy dissipated during the cyclic process. This approach allows the simulation of ULCF in regular cyclic tests, but also in non-regular cases such as seismic loads
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