White matter microstructure and cognitive function in young women with polycystic ovary syndrome

Context: Polycystic ovary syndrome (PCOS) is a disorder characterized by insulin resistance and hyperandrogenism, which leads to an increased risk of type 2 diabetes in later life. Androgens and insulin signaling affect brain function but little is known about brain structure and function in younger adults with PCOS. Objective: To establish whether young women with PCOS display altered white matter microstructure and cognitive function. Patients, interventions, and main outcome measures: Eighteen individuals with PCOS (age, 31 ± 6 y; body mass index [BMI] 30 ± 6 kg/m2) and 18 control subjects (age, 31 ± 7 y; BMI, 29 ± 6 kg/m2), matched for age, IQ, and BMI, underwent anthropometric and metabolic evaluation, diffusion tensor MRI, a technique especially sensitive to brain white matter structure, and cognitive assessment. Cognitive scores and white matter diffusion metrics were compared between groups. White matter microstructure was evaluated across the whole white matter skeleton using tract-based spatial statistics. Associations with metabolic indices were also evaluated. Results: PCOS was associated with a widespread reduction in axial diffusivity (diffusion along the main axis of white matter fibers) and increased tissue volume fraction (the proportion of volume filled by white or grey matter rather than cerebrospinal fluid) in the corpus callosum. Cognitive performance was reduced compared with controls (first principal component, t = 2.9, P = .007), reflecting subtle decrements across a broad range of cognitive tests, despite similar education and premorbid intelligence. In PCOS, there was a reversal of the relationship seen in controls between brain microstructure and both androgens and insulin resistance. Conclusions: White matter microstructure is altered, and cognitive performance is compromised, in young adults with PCOS. These alterations in brain structure and function are independent of age, education and BMI. If reversible, these changes represent a potential target for treatment

Dense urban typologies and the game of life: evolving cellular automata.

The ongoing rate of urbanization in China is the motivator behind this paper. As a response to the observed monotonous housing developments in Suzhou Industrial Park (SIP) and elsewhere, our method exploits Cellular Automata (CA) combined with fitness evaluation algorithms to explore speculatively the potential of existing developments and respective building regulations for increased density and diversity through an automated design algorithm. The well-known Game of Life CA is extended from its original two-dimensional functionality into the realm of three dimensions and enriched with the opportunity of resizing the involved cells according to their function. Moreover, our method integrates an earlier technique of constrcuctivists - namely the social condenser as a means of diversifying functional distribution within the Cellular Automata - as well as solar radiation as requested by the existing building regulation. The method achieves a densification of the development from 31% to 39% ratio of footprint to occupied volume whilst obeying the solar radiation rule and offering a more diverse functional occupation. This proof of concept demonstrates a solid approach to the automated design of housing developments at an urban scale with a limited evaluation procedure including solar radiation, which can be extended to other performance criteria in future work

A Class of Computationally Fast First Order Finite Volume Solvers: PVM Methods

In this work, we present a class of fast first order finite volume solvers, named as PVM (Polynomial Viscosity Matrix), for balance laws or, more generally, for nonconservative hyperbolic systems. They are defined in terms of viscosity matrices computed by a suitable polynomial evaluation of a Roe matrix. These methods have the advantage that they only need some information about the eigenvalues of the system to be defined, and no spectral decomposition of Roe Matrix is needed. As consequence, they are faster than Roe method. These methods can be seen as a generalization of the schemes introduced by Degond et al. in [12] for balance laws and nonconservative systems. The first-order path conservative methods to be designed here are intended to be used as the basis for higher order methods for multi-dimensional problems. In this work, some well known solvers as Rusanov, Lax-Friedrichs, FORCE (see [30], [8]), GFORCE (see [31], [8]) or HLL (see [18]) are redefined under this form, and then some new solvers are proposed. Finally, some numerical tests are presented and the performance of the numerical schemes are compared among them and with Roe schem

An investigation into using news analytics data in GARCH type volatility models

This thesis was submitted for the degree of Master of Philosophy and awarded by Brunel University.In the work we study different dynamic volatility models. We consider the family of ARCH and GARCH models to compare the performance of the models using both unconditional coverage Kupiec’s test and the test of conditional coverage proposed by Christoffersen. In-sample estimation procedure and out-of-sample evaluation will be based on General Electric stock market closing daily prices (January 2, 2008 - December 31, 2010). We consider different volatility models augmented with news analytics data to examine the impact of news intensity on stock volatility. First we consider two types of GARCH models: augmented with volume and augmented with news intensity. Based on empirical evidences for some of FTSE100 companies it will be shown that the GARCH(1,1) model augmented with volume does remove GARCH and ARCH effects for the most of the companies, while the GARCH(1,1) model augmented with news intensity has difficulties in removing the impact of log return on volatility. Then we compare GARCH model with jumps and GARCH–Jumps model augmented with news intensity using likelihood ratio test. The study shows that the problem of examining the impact of news intensity on volatility is far more sophisticated than it might seem at first sight. Some hypothesists and suggestions for future work are proposed in the final chapter.This work was funded by the Russian Government Programme ”National Research University”

Immiscible and miscible gas-oil displacements in porous media

Gas Injection is the second largest EOR process in U.S. To increase the extent of the reservoir contacted by displacing fluids, gas and water are injected intermittently - water-alternating-gas (WAG) process, is widely practiced. This experimental study is aimed at evaluating the WAG process performance in short and long cores as a function of gas-oil miscibility and brine composition. This performance evaluation has been carried out by comparing oil recoveries between WAG injection and continuous gas injection (CGI). Miscible (2500 psi) and immiscible (500 psi) floods were conducted using Berea cores, n-Decane and two different brines, namely the commonly used 5% NaCl solution and another the multicomponent brine from the West Texas Yates reservoir. Each of the ten corefloods consisted of series of steps including brine saturation, absolute permeability determination, flooding with oil (drainage) to initial oil saturation, flooding with brine (imbibition) to residual oil saturation, and finally, tertiary gas injection to recover the waterflood residual oil. It was found that comparing tertiary gas floods only on the basis of recovery yielded misleading conclusions. However, when oil recovery per unit volume of gas injection was used as a parameter to evaluate the floods, miscible gas floods were found more effective (recovery 60-70% higher) than immiscible floods. The WAG mode of injection out-performed the CGI floods. At increased gas volume injection, the performance of miscible CGI flood, inspite of the high injection pressure, approached the immiscible floods. A change in brine composition from 5% NaCl to 9.26% multivalent Yates reservoir brine showed a slight adverse effect on tertiary gas flood recovery due to increased solubility of CO2 in the latter. While immiscible WAG floods in short cores donot show appreciable improvement over CGI immiscible floods, WAG recovery was 31% higher than 6-ft CGI floods. The results of this study prompted a new process by combining CGI and WAG modes of gas injection. Such a process was found patented and practiced in the industry. In addition to providing performance characteristics of the WAG process, this study has indicated directions for further research aimed at improving oil recovery from gas injection processes

The influence of quantization process on the performance of global entropic thresholding algorithms using electrical capacitance tomography data

In measuring component fraction in multiphase flows using tomographic techniques, it is desirable to use a high speed tomography system capable of generating 100 tomograms per second. The electrical capacitance tomography system in this regard is considered to be the best among the available tomographic techniques. However, due to its inherent limitations the system generates distorted reconstructed tomograms necessitating the use of extra signal processing techniques such as thresholding to minimize these distortions. Whilst thresholding technique has been effective in minimizing distortions, the additional computation associated with the process limits the speed of tomogram generation desired from the system. Further, the accuracy of the techniques is limited to higher ranges of the full component fraction range. However, since its performance can be influenced by the nature of the quantization process required a priori, optimal quantization parameters can be found and used to improve performance. In this article the influence of quantization resolution and its rate on the performance of global entropic thresholding algorithms have been investigated. Measurement of gas volume component fraction in a multiphase flow of gas/liquid mixture using electrical capacitance tomography system has been used for evaluation using simulated and online capacitance measurement data. Results show that an optimal quantizer resolution is flow regime dependent. Higher resolutions are optimal for annular flow and vice versa for stratified flow regimes. Also, higher resolution significantly minimizes the dependency of the thresholding algorithm on the object to be searched, thereby reducing complexity of designing a thresholder. Overall, the optimal quantization resolution is 256. Tanzania Journal of Science Vol. 31 (2) 2005: pp. 63-7

Yield Performance of Locally Selected Cocoa Clones in North Luwu

Participatory selection in North Luwu District selected some locally cocoa clones, of which MCC 01 and MCC 02 the most promising to be developed as clonal material. This research has objectives to observe the stability performance of yield of these clones that enable be characterized of the potency as the basis for recommendation. Observation were carried out in 35 selected-farms be differentiated according to clone\u27s type, namely MCC 01, MCC 02 and Sulawesi 01 (control) and the year of planting (age). These farms were establised at the main area of cocoa in North Luwu. The assessed variables were the number of pod, yield components, the resistance to cocoa pod borer (CPB), vascular-streak dieback (VSD) and phytophthora pod rot (PPR). Data were recorded through 20 sampled-trees per farm in the period of April 2013 to April 2014 with monthly basis assessment. Data were analyzed refer to Eberhart & Russel method to perform stability parameters of the yield. The results indicate that these clones stable performing yield potency among plant age. MCC 01 and MCC 02 performed yield potency in amount of 3,682 kg/ha and 3,132 kg/ha respectively higher than Sulawesi 01 of 2,772 kg/ha. Evaluation of the resistance, MCC 01 having moderate resistance to CPB and VSD and resistance to PPR, however MCC 02 having resistance to CPB, VSD and PPR. Referring to the potency thus MCC 01 and MCC 02 were legally recommended as clonal material for farmers, restricted at the agroclimatic area similar to the condition in North Luwu