3-D Velocity Structures, Seismicity Patterns, and their Tectonic Implications across the Andean Foreland of San Juan Argentina

Three-dimensional velocity structures and seismicity patterns have been studied across the Andean Foreland of San Juan Argentina using data acquired by PANDA deployment. Distinct velocity variations are revealed between Precordillera in the west and Pie de Palo in the east. The low velocity anomaly beneath Precordillera is associated with the presence of thick sedimentary rock and thick sediment cover of Matagusanos valley. Similarly, the high velocity anomaly east of Eastern Precordillera is correlated with the presence of basement rocks. These anomalies are observed from the station corrections of Joint Hypocentral Determination (JHD) analysis. A northeast trending west dipping high velocity anomaly is imaged beneath the southern half of Pie de Palo. This anomaly represents a Grenvillian suture zone formed when Pie de Palo collided with the Precordillera. Relocated seismicity using 3-D Vp and Vs models obtained in this study revealed crustal scale buried faults beneath the Eastern Precordillera and Sierra de Pie de Palo. The fault defined by the seismicity extend down to a depth of ~40 km and ~35 km beneath Precordillera and Pie de Palo, respectively, defining the lower bound of the brittle to ductile transition of the crust. These results confirm that present day active crustal thickening involves the entire crust in the tectonic process and results in thick-skinned deformation beneath both the Eastern Precordillera and Pie de Palo. Based on the seismicity pattern, geomorphology, and velocity structures, Sierra Pie de Palo, a basement uplift block, can be divided into two separate semi-blocks separated by a northeast trending fracture zone. The northern block is characterized by a well-defined west dipping fault and low Vp/Vsration particularly at a depth of 12 to 16 km, while the southern block shows poorly-defined east dipping fault with high Vp/Vs ratio at a depth of 20 to 26 km. Spatial distribution of the well-relocated crustal earthquakes along these faults reveals that major deformation of the thick Andean crust in the region is mainly concentrated along localized regions.The geometry of the subducted Nazca plate defined by the relocation of 1040 intermediate depth events is flat at a depth of 100 ± 3 km until it resumes its normal subduction further to the east and south of the study area. The thickness of the seismogenic zone at intermediate depth is narrowly defined to 10 km within the flat subducting slab, a result that is a significant improvement from previous studies. Previous focal mechanism studies show dominant normal mechanism with tensional axis perpendicular to the trench axis indicating the likely mechanism of deformation is slab-pull (Stauder, 1973; Reta, 1992; and Anderson et al., 2007). Thus, the geometry of the subducting slab Nazca plate and their corresponding tectonic process can be better understood

A Fixed-Inverse Binary Misclassification Model Under Possible False-Positive Misclassification

In this project, we develop a particular statistical model for binary data that allows for the possibility of false-positive misclassification. To account for the misclassification, the model incorporates a two-stage sampling scheme. • Next, we apply maximum likelihood methods to find estimators of the primary prevalence parameter p as well as the false-positive misclassification rate parameter ϕ. In addition, we derive confidence intervals for p based on inverting Wald, score and likelihood ratio statistics. • Also, we graphically compare coverage and width properties of the Wald-based, score-based, and likelihood ratio-based confidence intervals for p through a Monte Carlo simulation. The simulation study is done under different parameter and sample size configurations. Also, we apply the newly-derived confidence intervals for p to a real data set

Breast cancer clinicopathological presentation, gravity and challenges in Eritrea, East Africa: Management practice in a resource-poor setting

Background. In Africa, breast cancer closely compares with cervical cancer as the most common malignancy affecting women and the incidence rates appear to be rising. Early detection of breast cancer is a key strategy for a good treatment outcome. However, there is no established protocol or guideline for management of breast cancer in Eritrea, East Africa.Objective. To assess the clinicopathological presentation, gravity and management challenges presented in breast cancer treatment in Eritrea. Methods. Our investigation was a retrospective, descriptive study to assess the clinical features and severity of breast cancer at time of presentation. We reviewed the medical records of all patients who presented with breast malignancies over the 2-year period from 1 January 2007 to 31 December 2008.Results. Eighty-two patients ranging in age from 26 - 80 years (mean 48 years) were included in the study. Of these 51% were premenopausal women; 61% of the patients presented with breast mass only and the remainder with manifestations of local (mass plus discharge, breast pain or breast ulceration) or distant metastatic disease. More than 60% of the patients presented after >2 years following onset of symptoms. Two-thirds of patients had late stage (III or IV) disease. All except one case was managed surgically. Conclusion. Most cases presented at younger age and advanced stage. These findings call for strengthening health education to promote early health-seeking behaviour and advocacy for the introduction of national screening, implementation of a management protocol and establishment of a radio-chemotherapy centre.

Analysis of the Gran Desierto, Pinacte Region, Sonora, Mexico, via shuttle imaging radar

The radar discriminability of geolian features and their geological setting as imaged by the SIR-A experiment is examined. The Gran Desierto and Pincate volcanio field of Sonora, Mexico was used to analyze the radar characteristics of the interplay of aeolian features and volcano terrain. The area in the Gran Desierto covers 4000 sq. km. and contains sand dunes of several forms. The Pincate volcanio field covers more than 2.000 sq. km. and consists primarily of basaltic lavas. Margins of the field, especially on the western and northern sides, include several maar and maar-like craters; thus obtaining information on their radar characteristics for comparison with impact craters

Efficiency Estimates of Public Health Center II Facilities in Southwestern Uganda

The study estimates the efficiency of public health centre II (HCII) facilities in Southwestern Uganda. Specifically, it determines the level of technical efficiency (TE), scale efficiency (SE) and estimates the economic savings required to make inefficient public health facilities efficient. An output-oriented Data Envelopment Analysis (DEA) is employed in the estimation of TE and SE. It was found out that 73 % of the HCIIs were technically inefficient while 27% were technically efficient. Mean TE stood at 72.3% implying that an average HCII could potentially improve its efficiency by increasing its outputs by 27.7%. In addition, 77% of the facilities were SE implying that they obtained the most productive scale size given the input-output combination. 23% of the facilities were scaled inefficient implying that they have more input waste attributable to their size. There is great potential for economic savings shown by different magnitudes of input reductions and output augmentations required to make inefficient facilities efficient. The study has important policy implications. The health sector should embark on rigorous periodic research and development to enhance healthcare delivery efficiently. Since the health units are small, there is a need  to augment their scale sizes and improve on their management practices so as to enhance their overall productivity and efficiency. Stakeholders should scale up efforts to attract, align skills with needs and improve retention and motivation of the health workforce. Holistic investment in resource inputs is essential. A comprehensive monitoring and evaluation plan with key verifiable indicators to monitor the overall health sector performance is required. &nbsp

Do fear indices help predict stock returns

This study investigates the forecasting power of implied volatility indices on forward looking returns. Prior studies document that negative innovations to returns are associated with increasing implied volatility of the underlying indices; thus, suggesting a possible relationship between extremely high levels of implied volatility and positive short term returns. We investigate this issue by examining the predictive power of three implied volatility indices, VIX, VXN and VDAX, on the underlying index returns. We extend previous research by also focusing on characterised selected stocks and examine the relationship between implied volatility indices and future returns across different sectors and classified portfolios. Our findings suggest that implied volatility indices are good predictors of 20-days and 60-days forward looking returns and illustrate insignificant predictive power for very short term (1-day and 5-days) returns

Climate change scenario simulations over Eritrea by using a fine resolution limited area climate model : temperature and moisture sensitivity

The climate of the eastern section of the Sahelian latitude, especially over the Eritrean subdomain, is often associated with long drought episodes from which the atmospheric mechanisms are poorly understood. In an effort to improve our knowledge of weather and climate systems over this region, the PRECIS Regional Climate Model (RCM) from the United Kingdom (UK) was obtained and implemented. Such a climate model that is based upon the physical laws of nature has the ability to simulate regional-scale atmospheric patterns, and therefore, may significantly contribute to our understanding of local atmospheric processes. In this dissertation the assessment of past regional climate trends from both observations and model simulations, and the simulation of scenarios for possible future climate change were regarded as important. To investigate this, the PRECIS RCM was first nested over the Eritrean domain into the “atmosphere only” HadAM3H global General Circulation Model (GCM) and forced at its lateral boundaries by a 30-year present-day (1961-1990) integration of the same global model. Secondly, the PRECIS RCM was constrained at its lateral boundary by the “fully coupled” HadCM3 GCM (for Sea Surface Temperatures (SSTs) and sea-ice) and its improved atmospheric component (HadAM3H GCM). The latter simulations provided boundary conditions for the A2 and B2 future emission scenarios (Special Report on Emission Scenarios (SRES)) to simulate a 20-year (2070-2090) projection of future climate. These experiments allowed for verification of both spatial and temporal present-day climate simulations, as well as possible future climate trends as simulated by the PRECIS RCM over the Eritrean domain, with specific emphasis on temperature and moisture related variables. The study indicates that PRECIS RCM climate simulations are mostly in harmony with observed spatial patterns. This skill may be attributed to the full representation of the climatic system (land surface, sea, ice, atmosphere and atmospheric chemistry such as sulphur and greenhouse gasses) in the model configuration. However, when comparing PRECIS RCM results with the much coarser resolution (2.5ox2.5o) National Centre for Environmental Prediction (NCEP) reanalysis data, obvious differences do occur. These differences are not necessarily the result of poor model performance, but may be attributed to more detailed simulations over the finer RCM grid (0.44o x 0.44o). Future climate scenario simulation with the PRECIS RCM over Eritrea produce increased surface temperature in both the A2 and B2 SRES scenario integrations, relative to the present climatology. This temperature increase also appears in the driving GCM (HadCM3) as well as in other GCM results from the Inter Governmental Panel for Climate Change (IPCC) initiative. There are, however, mixed signals in rainfall projections. According to PRECIS RCM results, rainfall is expected to increase in most of the Eritrean region. Copyright 2005, University of Pretoria. All rights reserved. The copyright in this work vests in the University of Pretoria. No part of this work may be reproduced or transmitted in any form or by any means, without the prior written permission of the University of Pretoria. Please cite as follows: Beraki, A F 2005, Climate change scenario simulations over Eritrea by using a fine resolution limited area climate model : temperature and moisture sensitivity , MSc dissertation, University of Pretoria, Pretoria, viewed yymmdd Dissertation (MSc)--University of Pretoria, 2007.Geography, Geoinformatics and MeteorologyUnrestricte