Spectral interferometric polarised coherent anti-Stokes Raman spectroscopy

We have developed an interferometric implementation of coherent anti-Stokes Raman scattering (CARS) which enables broadband coherent Raman spectroscopy free from non-resonant background (NRB), with a signal strength proportional to concentration. Spectra encode mode symmetry information into the amplitude response which can be directly compared to polarised spontaneous Raman spectra. The method requires only passive polarisation optics and is suitable for a wide range of laser linewidths and pulse durationsComment: 5 pages, 3 figures, submitted to PR

Finite-element simulations of earthquakes

This thesis discusses simulations of earthquake ground motions using prescribed ruptures and dynamic failure. Introducing sliding degrees of freedom led to an innovative technique for numerical modeling of earthquake sources. This technique allows efficient implementation of both prescribed ruptures and dynamic failure on an arbitrarily oriented fault surface. Off the fault surface the solution of the three-dimensional, dynamic elasticity equation uses well known finite-element techniques. We employ parallel processing to efficiently compute the ground motions in domains containing millions of degrees of freedom. Using prescribed ruptures we study the sensitivity of long-period near-source ground motions to five earthquake source parameters for hypothetical events on a strike-slip fault (Mw 7.0 to 7.1) and a thrust fault (Mw 6.6 to 7.0). The directivity of the ruptures creates large displacement and velocity pulses in the ground motions in the forward direction. We found a good match between the severity of the shaking and the shape of the near-source factor from the 1997 Uniform Building Code for strike-slip faults and thrust faults with surface rupture. However, for blind thrust faults the peak displacement and velocities occur up-dip from the region with the peak near-source factor. We assert that a simple modification to the formulation of the near-source factor improves the match between the severity of the ground motion and the shape of the near-source factor. For simulations with dynamic failure on a strike-slip fault or a thrust fault, we examine what constraints must be imposed on the coefficient of friction to produce realistic ruptures under the application of reasonable shear and normal stress distributions with depth. We found that variation of the coefficient of friction with the shear modulus and the depth produces realistic rupture behavior in both homogeneous and layered half-spaces. Furthermore, we observed a dependence of the rupture speed on the direction of propagation and fluctuations in the rupture speed and slip rate as the rupture encountered changes in the stress field. Including such behavior in prescribed ruptures would yield more realistic ground motions

The impact of college student immersion service learning trips on coping with stress and vocational identity

This study examined the impact of service learning immersion trips on vocational identity and coping with stress among college students. Fifty-one students (15 males, 36 females) who participated in immersion trips and 76 students (25 males, 51 females) in a non-immersion control group completed a series of questionnaires directly before and immediately after both fall and spring break immersion trips, and during a four-month follow up. Results suggest that, after returning from an immersion trip, students report a greater ability to cope with stress and a somewhat stronger sense of vocational identity relative to students who do not participate in immersion trips

Long-Period Building Response to Earthquakes in the San Francisco Bay Area

This article reports a study of modeled, long-period building responses to ground-motion simulations of earthquakes in the San Francisco Bay Area. The earthquakes include the 1989 magnitude 6.9 Loma Prieta earthquake, a magnitude 7.8 simulation of the 1906 San Francisco earthquake, and two hypothetical magnitude 7.8 northern San Andreas fault earthquakes with hypocenters north and south of San Francisco. We use the simulated ground motions to excite nonlinear models of 20-story, steel, welded moment-resisting frame (MRF) buildings. We consider MRF buildings designed with two different strengths and modeled with either ductile or brittle welds. Using peak interstory drift ratio (IDR) as a performance measure, the stiffer, higher strength building models outperform the equivalent more flexible, lower strength designs. The hypothetical magnitude 7.8 earthquake with hypocenter north of San Francisco produces the most severe ground motions. In this simulation, the responses of the more flexible, lower strength building model with brittle welds exceed an IDR of 2.5% (that is, threaten life safety) on 54% of the urban area, compared to 4.6% of the urban area for the stiffer, higher strength building with ductile welds. We also use the simulated ground motions to predict the maximum isolator displacement of base-isolated buildings with linear, single-degree-of-freedom (SDOF) models. For two existing 3-sec isolator systems near San Francisco, the design maximum displacement is 0.5 m, and our simulations predict isolator displacements for this type of system in excess of 0.5 m in many urban areas. This article demonstrates that a large, 1906-like earthquake could cause significant damage to long-period buildings in the San Francisco Bay Area

Analysis of Shale Production Performance Using Decline Curve Methods

With the recent development of shale gas reservoirs such as the Marcellus using horizontal drilling and fracturing, it has become necessary to evaluate the amount of gas recoverable for both economic and operational purposes. As a result of limited production history, the production behavior of horizontal well producing from Marcellus shale has not been well established. A technique in accomplishing the estimation of future production history would be most useful to the industry.;Decline curve analysis (DCA) methods have been utilized successfully in various hydrocarbon plays throughout the world in approximating future production. Several DCA models have been proposed specifically for unconventional gas reservoirs. However, their applicability to production data from Marcellus shale wells has not been attempted. Four sets of simulated Marcellus shale production profiles were generated in this study. They included production from a 3000 feet-long horizontal well containing seven hydraulic fracture stages (a hydraulic fracture spacing of 500 feet) and thirteen fractures (a hydraulic fracture spacing of 250 feet). Two sets were simulated using a dual porosity model with adsorbed gas and two sets were simulated using a dual porosity model without adsorbed gas. The most appropriate DCA models for each set were selected based on the entire production profile (30 years). Subsequently, a technique was developed to predict the long term DCA model parameters based on the limited production history via dimensionless log-log plots. Finally, the developed methodology was applied to the limited field production data from a horizontal well containing eight hydraulic fracture stages (a hydraulic fracture spacing of 429 feet). The comparison of the predicted future production rates with those rates predicted by history matching with a commercial reservoir simulator confirmed the reliability of methodology developed in this study

Autism-associated SNPs in the clock genes _npas2_, _per1_ and the homeobox gene _en2_ alter DNA sequences that show characteristics of microRNA genes.

Intronic single nucleotide polymorphisms (SNPs) in the clock genes _npas2_ and _per1_ and the homeobox gene _en2_ are reported to be associated with autism. This bioinformatics analysis of the intronic regions which contain the autism-associated SNPs rs1861972 and rs1861973 in _en2_, rs1811399 in _npas2_, and rs885747 in _per1_, shows that these regions encode RNA transcripts with predicted structural characteristics of microRNAs. These microRNA-like structures are disrupted _in silico_ by the presence of the autism enriched alleles of rs1861972, rs1861973, rs1811399 and rs885747 specifically, as compared with the minor alleles of these SNPs. The predicted gene targets of these microRNA-like structures include genes reported to be implicated in autism (_gabrb3_, _shank3_) and genes causative of diseases co-morbid with autism (_mecp2_ and _rai1_). The inheritance of the AC haplotype of rs1861972 - rs1861973 in _en2_, the C allele of rs1811399 in _npas2_, and the C allele of rs1234747 in _per1_ may contribute to the causes of autism by affecting microRNA genes that are co-expressed along with the homeobox gene _en2_ and the circadian genes _npas2_ and _per1_

Molecular mechanisms controlling bovine lymphocyte homing

The cDNA clones encoding for the bovine glycoproteins CD44 and LECAM-1 (lectin cell adhesion molecule-1) were isolated and sequenced. The predicted amino acid sequences of bovine CD44 and LECAM-1 had high identities with those of human and murine CD44 and LECAM-1. The high identities of the predicted amino acid sequences of these glycoproteins in the bovine, human and mouse suggest they may have similar functions in all three species. While the overall amino acid identities were high, bovine CD44 had an area of low identity with human and murine CD44 in the extracellular domain and the cytoplasmic tail of bovine LECAM-1 had low identity with the cytoplasmic tails of human and murine LECAM-1;Human CD44 has been previously reported to be involved in the recirculation or homing of human lymphocytes to high-walled endothelial venules (HEV) in lymphoid tissue. While the predicted amino acid sequence of bovine CD44 was determined to be similar to human CD44, the role of bovine CD44 in lymphocyte homing was not determined in this study;Bovine LECAM-1, like human and murine LECAM-1, contained a lectin domain that likely controls the homing of peripheral lymphocytes as fructose-1-phosphate and fucoidin blocked the binding of bovine lymphocytes to peripheral lymph node HEV. Neuraminidase and phorbol myristate acetate treatments affected the binding of bovine, human, and murine lymphocytes to murine peripheral lymph node HEV in a similar manner in all three species. A monoclonal antibody that recognizes human LECAM-1 blocked the binding of bovine lymphocytes to peripheral lymph node HEV, but not Peyer\u27s patch HEV. Expression of bovine LECAM-1 was high in peripheral lymph nodes and low in Peyer\u27s patches. These data strongly suggest that LECAM-1 is an evolutionarily conserved molecule and that bovine LECAM-1, like human and a murine LECAM-1, is a peripheral lymphocyte homing receptor

Teaching Against Tradition: Historical Preludes to Critical Pedagogy

This dissertation revises the historical narrative of critical pedagogy in college writing classrooms. It argues that the key principles of critical pedagogy, first articulated by Paulo Freire in Pedagogy of the Oppressed, were practiced by a number of pedagogues as early as the eighteenth century. It examines the teaching practices of these men and shows that they anticipated the methods of critical pedagogy. This dissertation spotlights the need to reinterpret the history of critical pedagogy and to select a wider lens through which to understand the current pedagogical scene. Chapter I defines critical pedagogy as method and explains the Freirean project. Chapter II locates parallels between critical pedagogy and the process and expressive pedagogies of the late 1960s and early '70s. Specifically, it argues that the works of Peter Elbow and Donald Murray embody the principles of critical pedagogy. Their emphasis on the epistemological power of language, for example, prefigures the theoretical foundation upon which Freire constructs his critical methodology. Chapter III argues that the pedagogical advancements of I. A. Richards in the early twentieth century anticipated the teaching methods of critical pedagogy, especially insofar as they established student-centered writing classrooms. Richards's attempts to place student interpretations at the center of the course situate his pedagogy more comfortably among contemporary approaches to writing instruction like critical pedagogy than it does among the formalist approaches to which he is generally linked. Chapter IV argues that Isaac Watts and Philip Doddridge, two eighteenth-century educators, employ teaching methods that parallel contemporary critical pedagogy. Foremost, Watts and Doddridge create participatory learning environments that center on practical subjects. They are among the first educators to teach in the English vernacular and to supplement the traditional classical curriculum with new learning. Chapter V examines the historical contexts in which these preludes to critical pedagogy emerge and shows that Murray, Elbow, Richards, Watts, and Doddridge taught at times when educational access was expanding. It argues that their pedagogies developed in an effort to address classroom diversity and to discover strategies for bringing people into dialogue with each other about the world