Elastic geobarometry for anisotropic inclusions in cubic hosts

Mineral inclusions entrapped in other minerals may record the local stresses at the moment of their entrapment in the deep Earth. When rocks are exhumed to the surface of the Earth, residual stresses and strains may still be preserved in the inclusion. If measured and interpreted correctly through elastic geobarometry, they give us invaluable information on the pressures (P) and temperatures (T) of metamorphism. Current estimates of P and T of entrapment rely on simplified models that assumes that the inclusion is spherical and embedded in an infinite host, and that their elastic properties are isotropic. We report a new method for elastic geobarometry for anisotropic inclusions in quasi-isotropic hosts. The change of strain in the inclusion is modelled with the axial equations of state of the host and the inclusion. Their elastic interaction is accounted for by introducing a 4th rank tensor, the relaxation tensor, that can be evaluated numerically for any symmetry of the host and the inclusion and for any geometry of the system. This approach can be used to predict the residual strain/stress state developed in an inclusion after exhumation from known entrapment conditions, or to estimate the entrapment conditions from the residual strain measured in real inclusions. In general, anisotropic strain and stress states are developed in non-cubic mineral inclusions such as quartz and zircon, with deviatoric stresses typically limited to few kbars. For garnet hosts, the effect of the mutual crystallographic orientation between the host and the inclusion on the residual strain and stress is negligible when the inclusion is spherical and isolated. Assuming external hydrostatic conditions, our results suggest that the isotropic and the new anisotropic models give estimations of entrapment conditions within 2%

Analysis of the (1+1) EA on LeadingOnes with Constraints

Understanding how evolutionary algorithms perform on constrained problems has gained increasing attention in recent years. In this paper, we study how evolutionary algorithms optimize constrained versions of the classical LeadingOnes problem. We first provide a run time analysis for the classical (1+1) EA on the LeadingOnes problem with a deterministic cardinality constraint, giving $\Theta(n (n-B)\log(B) + n^2)$ as the tight bound. Our results show that the behaviour of the algorithm is highly dependent on the constraint bound of the uniform constraint. Afterwards, we consider the problem in the context of stochastic constraints and provide insights using experimental studies on how the ($\mu$+1) EA is able to deal with these constraints in a sampling-based setting

Essays on farm household credit constraint, productivity and consumption inequality in Malawi

Credit has proven to be a necessary tool for economic development affecting positively the welfare of households and individuals. However, one major area in which rural households lack is access to financial markets including credit. The studies included in this thesis contribute to the access to credit literature and the credit constraint/unconstraint impact on some welfare outcomes. The first empirical study examined farm households' access to credit in rural Malawi. Unlike previous empirical studies, particular attention is given to discouraged borrowers who are mostly ignored in such studies. Using the 2010/2011 household survey data from Malawi the study determines the demographic and socio-economic characteristics that distinguish farm households who need credit, who are the discouraged borrowers and who are rejected applicants. A three-step sequential estimation model following a trivariate probit model with double sample selection was adopted. The findings revealed that there were over 7 times more discouraged borrowers than denied applicants. Women were more likely to be discouraged from applying for credit but, if they applied, they were more likely to be successful in obtaining credit than males. This shows that when examining farm households' access to credit discouraged borrowers should be given special consideration. Capturing discouraged borrowers as also credit constrained, the second empirical study employed a switching model to estimate the impact of credit constraint status on farm productivity for each credit constraint regime. The study further compared the expected production under actual and counterfactual conditions for a household being credit constrained or unconstrained. The findings suggest that a household that is constrained is less productive than a randomly selected household from the sample would but that for the unconstrained household is inconclusive, however, the counterfactual arguments as seen from the analysis shows that being credit unconstrained was beneficial to the increase in productivity. Studies have shown that undeveloped financial markets have been a major contributing factor increasing inequality, especially in developing countries. The third empirical study examined the impact of household credit constraint on the consumption inequality of rural households in Malawi. Factors that explain the within and between credit constrained and unconstrained status of consumption inequality were examined. The General Entropy (GE) Index and the Regression-Based Inequality Decomposition Methods, Field's (2003) and Blinder-Oaxaca Decomposition were employed. The findings show that inequality was more prominent within the groups than between them. Also, the size of households and the value of assets were the major contributors to the within-group inequalities for credit constrained and unconstrained households. Further, only the endowment component was important in explaining the consumption inequality gap between the credit constrained and unconstrained households. Adjusting the level of endowments of constrained households to that of the unconstrained households increased their welfare by 15.7 percent

A Review of the Travel Behavior Analysis: Its Basis and Application for Developing Cities

Travel, most often viewed in theory as derived from the demand for activity participation, has almost always been modeled on the trip-based basis, i.e., the trip is treated as the unit of analysis. Attributes of a trip (e.g., its origin and destination, mode, length) have been the subjects of analysis, but not the types of activities engaged in, their durations, sequences, and timing. This paper offers a brief review of the travel behavior analysis in order to provide a better understanding and forecasting of travel behavior. The article further offers discussions on its possible applications in urban areas of developing countries where historical accumulations of transportation and communications technologies are being introduced within a short span of time, creating the environment for travel which may not be properly accounted for using the conventional trip-based models of travel demand. In addition, the dataset from Malaysia was employed as a case of study

The adsorption structure of furan on Pd(1 1 1)

The structure of molecular furan, C4H4O, on Pd(1 1 1) has been investigated by O K-edge near-edge X-ray absorption fine structure (NEXAFS) and C 1s scanned-energy mode photoelectron diffraction (PhD). NEXAFS shows the molecule to be adsorbed with the molecular plane close to parallel to the surface, a conclusion confirmed by the PhD analysis. Chemical-state specific C 1s PhD data were obtained for the two inequivalent C atoms in the furan, the α-C atoms adjacent to the O atom, and the β-C atoms bonded only to C atoms, but only the PhD modulations for the α-C emitters were of sufficiently large amplitude for detailed evaluation using multiple scattering calculations. This analysis shows the α-C atoms to be located approximately 0.6 Å off-atop surface Pd atoms with an associated C–Pd bondlength of 2.13 ± 0.03 Å. Two alternative local geometries consistent with the data place the O atom in off-atop or near-hollow locations, and for each of these local structures there are two equally-possible registries relative to the fcc and hcp hollow sites. The results are in good agreement with earlier density functional theory calculations which indicate that the fcc and hcp registries are equally probable, but the PhD results fail to distinguish the two distinct local bonding geometries