A laboratory Study of Polymer Rheology in Bulk and in Sandstone Cores with Application to German Oilfields

Imperial Users onl

Analytical study of the effects of clouds on the light produced by lightning

Researchers consider the scattering of visible and infrared light due to lightning by cubic, cylindrical and spherical clouds. The researchers extend to cloud physics the work by Twersky for single and multiple scattering of electromagnetic waves. They solve the interior problem separately to obtain the bulk parameters for the scatterer equivalent to the ensemble of spherical droplets. With the interior solution or the equivalent medium approach, the multiple scattering problem is reduced to that of a single scatterer in isolation. Hence, the computing methods of Wiscombe or Bohren specialized to Mie scattering with the possibility for absorption were used to generate numerical results in short computer time

Analytical optical scattering in clouds

An analytical optical model for scattering of light due to lightning by clouds of different geometry is being developed. The self-consistent approach and the equivalent medium concept of Twersky was used to treat the case corresponding to outside illumination. Thus, the resulting multiple scattering problem is transformed with the knowledge of the bulk parameters, into scattering by a single obstacle in isolation. Based on the size parameter of a typical water droplet as compared to the incident wave length, the problem for the single scatterer equivalent to the distribution of cloud particles can be solved either by Mie or Rayleigh scattering theory. The super computing code of Wiscombe can be used immediately to produce results that can be compared to the Monte Carlo computer simulation for outside incidence. A fairly reasonable inverse approach using the solution of the outside illumination case was proposed to model analytically the situation for point sources located inside the thick optical cloud. Its mathematical details are still being investigated. When finished, it will provide scientists an enhanced capability to study more realistic clouds. For testing purposes, the direct approach to the inside illumination of clouds by lightning is under consideration. Presently, an analytical solution for the cubic cloud will soon be obtained. For cylindrical or spherical clouds, preliminary results are needed for scattering by bounded obstacles above or below a penetrable surface interface

Evaluation of Stem-Loop Reverse Transcription and Poly-A Tail Extension in MicroRNA Analysis of Body Fluids

MicroRNA has been demonstrated to be a viable tool for body fluid identification purposes in forensic casework. Stem-loop reverse transcription (slRT) is regularly used for cDNA synthesis from mature miRNA, along with poly-A tail extension. Both have been used in a forensic context, but no direct comparison has been carried out. It has also not been shown whether poly-A tail extension can be used upon DNA extracts, as previously shown with slRT. Blood and saliva samples were collected and underwent DNA extraction with or without on-column DNA digestion. All samples were then aliquoted and underwent slRT and poly-A tail extension separately. qPCR was then conducted targeting microRNA markers hsa-miR-451 and hsa-miR-205. It was shown that the DNA digestion step did not affect the ability to differentiate between blood and saliva. It was also shown that this differentiation was possible using poly-A tail extension, and that poly-A tail extension exhibited more amplification than slRT. So whilst the choice of slRT and poly-A tail extension for the purpose of forensic body fluid identification is not critical, it may be best to use poly-A tail extension, particularly where there are low traces of sample

A Case Study in Developing an Apologetic Discipleship Model Among Second Generation Haitians in Florida

This thesis seeks to demonstrate that equipping second-generation Haitian believers in Florida requires a contextually-appropriate, apologetics discipleship model. This project starts with an examination of the weakness or absence of the use of current apologetics discipleship among second-generation Haitians, which gives birth to unequipped second-generation Haitians ravaged by worldview conflict and who leave the church in record numbers. Building upon this foundation, this work sheds light on a cultural shift among second-generation Haitians. The objective is to isolate some key discipleship factors among second-generation Haitians in Florida by examining the fear of some Haitian pastors to address voodoo and its influence on secondgeneration Haitian believers. Such inaction has negative impacts on them from the loss of confidence in their pastors and God’s Word. The discipleship chain being broken leads to syncretism and the drifting away of second-generation Haitians from the church and even the unsubscribing from the biblical worldview. In addition, this thesis will map out what a vibrant community of disciples among second-generation Haitians in Florida looks like and how it can be achieved by training Haitian pastors both theologically and apologetically. It also will encourage viable training venues to include apologetics in their programs. Finally, it will encourage disciple-makers to teach second-generation Haitian believers a thorough biblical worldview to defend their faith through love and the use of the mind in this culture of feeling

Sustainable Development in Sub-Saharan Africa: Strategies for Self-help in Food Production, Case Study of Kenya

This thesis analyses the food crisis in sub-Saharan Africa in the 1980s and 1990s, identifies roots of the problem, and proposes strategies of sustainable development based on self-sufficiency in food production for domestic needs. The main goal of this research has been to devise development strategies centered on development of the food production sector. The thesis strongly suggests that countries of the region should consider developing the food production sector to experience any meaningful development, and to escape a dark future of food shortages and food dependency on developed economies. Investigation into Development Economics, Dependency, Underdevelopment, and Modernization theories has provided a basis to justify that improvement of the food production sector is an urgent necessity for sub-Saharan African countries. The thesis uses a comparative analytical methodology based on a historical study of Kenya from the colonial period to the 1990s. The food crisis is identified as a common problem for many countries in sub-Saharan Africa and its general causes are investigated: ( 1) low output productivity of traditional methods and technology, (2) harsh ecological environment with frequent droughts and soil erosion, (3) neglect of food production in the policies and priorities of governments, ( 4) poor marketing and distribution of foodstuffs, (5) fast population growth. Kenya is then used as a model to confirm the hypothesis that roots of the crisis are strongly linked to the colonial setting of these economies as cash crop and raw material producers. Also, neglect of the food production sector in government policy is matched in the Kenyan case. Kenya\u27s food crisis can be explained by two sets of factors. On the input side of the food production sector, reasons found were ( 1) government emphasis on cash crops to the neglect of food production, and (2) underdeveloped technology and agricultural methods used in food production. On the output side, food shortages are due to ( 1) an inefficient marketing and distribution system, (2) inefficient pricing policies, and (3) fast population growth. A model of five solutions is presented which puts emphasis, on the input side, on (1) a shift of policies from cash crop production to accommodate food crop production as a viable economic development policy, (2) curbing food imports, and (3) boosting domestic food production by empowering women, attracting men to the food production activity, reorganizing production, and improving agricultural technology and methods. On the output side the solutions call for ( 4) reorganizing and improving the distribution, and marketing, and pricing of foodstuffs, and (5) developing rural economies around the food production sector and the agribusiness industry

Full Disclosure: Model Uncertainty in Adjusting for Confounders

This study examines the role of knowledge about underlying causal relationships in classifying controls in order to mitigate omitted- and included-variable biases. Using simulations and accounting examples, the study shows that the researcher may not distinguish good and bad controls because the underlying causal relationships are unobservable, and remedying strategies (such as the relative timing of measurement) may not remove the uncertainty in the classification. Because of the uncertainty about which controls to use, two or more models will be credible as will the distinct estimates derived from them. Next, the study shows that the current standard practice of singling out a preferred model (e.g., one about which the researcher is most confident) masks model uncertainty and is generally not supported by theories of rational decision making under uncertainty. Specifically, relying on the estimate from a preferred model will often involve higher risks in statements made from the study than relying on another estimate or combination of estimates. Accordingly, the study recommends that the researcher disclose all the relevant credible estimates without signalling which estimate is more important or choose an applicable theory that recommends which estimate to rely on in making conclusions and other important statements from their study

Fundamental length in quantum theories with PT-symmetric Hamiltonians

The direct observability of coordinates x is often lost in PT-symmetric quantum theories. A manifestly non-local Hilbert-space metric $\Theta$ enters the double-integral normalization of wave functions $\psi(x)$ there. In the context of scattering, the (necessary) return to the asymptotically fully local metric has been shown feasible, for certain family of PT-symmetric toy Hamiltonians H at least, in paper I (M. Znojil, Phys. Rev. D 78 (2008) 025026). Now we show that in a confined-motion dynamical regime the same toy model proves also suitable for an explicit control of the measure or width $\theta$ of its non-locality. For this purpose each H is assigned here, constructively, the complete menu of its hermitizing metrics $\Theta=\Theta_\theta$ distinguished by their optional "fundamental lengths" $\theta\in (0,\infty)$. The local metric of paper I recurs at $\theta=0$ while the most popular CPT-symmetric hermitization proves long-ranged, with $\theta=\infty$.Comment: 31 pp, 3 figure