Development of a Long-Period Torsion Balance for Tests of Einstein\u27s Equivalence Principle and a Search for Normal Mode Torsional Oscillations of the Earth

This thesis describes the development of a torsion balance experiment designed to test Einstein\u27s equivalence principle with unprecedented sensitivity, while also taking a novel approach to directly observe the normal mode torsional oscillations of the Earth. Accordingly, a model of the signal expected from a potential equivalence principle violation has been developed, as well as a multi-slit auto-collimating optical lever which possesses a resolution on the order of a nanoradian and a range of observation of 10 milliradians and is used to monitor the torsion balance. A torsion balance with a natural torsional frequency of ~104 Hz, signi_cantly below the frequency of the longest of the Earth\u27s normal modes, was designed, built, and operated in a remote laboratory at Washington University\u27s Tyson Research Center. More than 1800 hours of data was collected and used to evaluate the performance of this prototype instrument and characterize the conditions in the Tyson laboratory

Unscripting Piety: Muslim Women, Pakistani Nationalism, and Islamic Feminism

This dissertation analyzes Muslim womens processes of pious subject formation and the intersection of these processes with discourses of Pakistani nationalism and Islamic feminism. Drawing primarily on interviews and participatory observations with Pakistani women in Karachi, Islamabad, and Mississauga associated with two Sunni Muslim groups, Al-Huda International and the Jamaat-e-Islami, I examine how women comprehend and inhabit their piety in and through the spiritual, social, and political milieu of their everyday lives. I argue that taking up piety while understanding the spiritual as epistemological reveals contradictory and relational dimensions of Muslim womens subjectivities, including complicities with structures of power and relationships with the secular. By taking up religiosity as a way of knowing, this dissertation intervenes in the normative secularity of knowledge production about Muslim women that renders the epistemic dimension of their pious subjectivities unintelligible. To explicate what analytical openings are enabled by taking up the spiritual as epistemological, I look at how the women I conducted research with conceptualize their piety and how their Islamic discourse coalesces, contradicts and co-exists with dominant discourses of Islam, religio-nationalism, and universal rights-based feminism. I begin with an exploration of the spaces created for Muslim women through Al-Huda and the Jamaat and what these spaces meant to the women I met. I juxtapose my respondents Islamic praxis with a discourse analysis of Pakistani religio-nationalism and rights-based Islamic feminism that also stake a claim on defining the relationship between women and Islam. These discursive structures of nationalism and feminism anchor analyses of Muslim womens piety in secular epistemologies that render practices such as veiling or the qawwam (authoritative status) of men, for example, in secular terms. Focusing on how the women I interviewed conceptualize qawwam, I elucidate the paradoxical processes by which they implement an ostensible gendered hierarchy, often in face of resistant men, in their everyday lives. I then turn to how their piety is complicit with structures of power by examining how the focus on scripture in their literalist Islamic praxis secures a rational subject of piety

A feasibility study of a home-based exercise intervention for prostate cancer patients on androgen deprivation therapy

Purpose: Androgen deprivation therapy (ADT) is an effective treatment for advanced-stage prostate cancer. Unfortunately, ADT has several adverse effects that significantly impair health-related quality of life (HRQOL). In patients receiving ADT, resistance training has been shown to improve important physical and psychosocial outcomes. However, little is known about the effects of aerobic exercise in this population. This feasibility study compares the effects of aerobic and resistance exercise interventions on a panel of psychological, physical fitness, and biological outcomes related to prostate cancer and ADT. Methods: 66 men receiving ADT for prostate cancer were recruited for this prospective, randomized trial. Participants are assigned to either a resistance or aerobic, moderate-intensity exercise 3-5 times per week for 30-60 minutes/session. Participants were provided with equipment so that they could exercise at home. The primary outcomes were related to feasibility for future, large-scale trials. Secondary outcomes included: fatigue, HRQOL, physical fitness, adipokines, insulin-like growth factor axis proteins, and exercise adherence. Outcomes were assessed at baseline and at 3, 6, and 12 months. Results: Preliminary findings are presented. 205 patients were approached for participation, 66 of which agreed to participate (n=34 in the resistance training group and 32 in the aerobic training group). Over the intervention period we experienced an attrition rate of 33%. There were no adverse events and biweekly booster sessions were poorly attended (n=27 aerobic training participants and n=22 resistance training participants did not attend any booster sessions). Intention-to-treat analyses showed that fatigue and HRQOL were not significantly different between groups; however, in a per-protocol analysis the resistance-training group demonstrated clinically significant improvements in HRQOL. Differential within-groups effects on physical fitness and biomarkers were also observed at various time-points. At all time-points, the aerobic training group engaged in significantly more physical activity than the resistance training group. Conclusion: Our findings suggest that both resistance and aerobic training can have positive effects on body composition with differential effects on psychosocial and biological outcomes. It appears that the aerobic exercise intervention was more effective at producing long-term, clinically significant increases in physical activity volume than resistance training. Our study has set the framework to conduct future clinical trials investigating the effects of exercise in men treated for prostate cancer

Managing for change: October 11, 1989

Bi-weekly newsletter of University Hospital's Change Project, provided to managers at the hospital

A Streamlined, Bi-Organelle, Multiplex PCR Approach to Species Identification: Application to Global Conservation and Trade Monitoring of the Great White Shark, Carcharodon carcharias

The great white shark, Carcharodon carcharias, is the most widely protected elasmobranch in the world, and is classified as Vulnerable by the IUCN and listed on Appendix III of CITES. Monitoring of trade in white shark products and enforcement of harvest and trade prohibitions is problematic, however, in large part due to difficulties in identifying marketed shark parts (e.g., dried fins, meat and processed carcasses) to species level. To address these conservation and management problems, we have developed a rapid, molecular diagnostic assay based on species-specific PCR primer design for accurate identification of white shark body parts, including dried fins. The assay is novel in several respects: It employs a multiplex PCR assay utilizing both nuclear (ribosomal internal transcribed spacer 2) and mitochondrial (cytochrome b) loci simultaneously to achieve a highly robust measure of diagnostic accuracy; it is very sensitive, detecting the presence of white shark DNA in a mixture of genomic DNAs from up to ten different commercially fished shark species pooled together in a single PCR tube; and it successfully identifies white shark DNA from globally distributed animals. In addition to its utility for white shark trade monitoring and conservation applications, this highly streamlined, bi-organelle, multiplex PCR assay may prove useful as a general model for the design of genetic assays aimed at detecting body parts from other protected and threatened species

Local seismicity around the Chain Transform Fault at the Mid-Atlantic Ridge from OBS observations

Summary Seismicity along transform faults provides important constraints for our understanding of the factors that control earthquake ruptures. Oceanic transform faults are particularly informative due to their relatively simple structure in comparison to their continental counterparts. The seismicity of several fast-moving transform faults has been investigated by local networks, but as of today there been few studies of transform faults in slow spreading ridges. Here we present the first local seismicity catalogue based on event data recorded by a temporary broadband network of 39 ocean bottom seismometers located around the slow-moving Chain Transform Fault (CTF) along the Mid-Atlantic Ridge (MAR) from March 2016 to March 2017. We locate 972 events in the area by simultaneously inverting for a 1-D velocity model informed by the event P- and S-arrival times. We refine the depths and focal mechanisms of the larger events using deviatoric moment tensor inversion. Most of the earthquakes are located along the CTF (700) and Romanche transform fault (94) and the MAR (155); a smaller number (23) can be observed on the continuing fracture zones or in intraplate locations. The ridge events are characterised by normal faulting and most of the transform events are characterised by strike slip faulting, but with several reverse mechanisms that are likely related to transpressional stresses in the region. CTF events range in magnitude from 1.1 to 5.6 with a magnitude of completeness around 2.3. Along the CTF we calculate a b-value of 0.81 ± 0.09. The event depths are mostly shallower than 15 km below sea level (523), but a small number of high-quality earthquakes (16) are located deeper, with some (8) located deeper than the brittle-ductile transition as predicted by the 600˚C-isotherm from a simple thermal model. The deeper events could be explained by the control of seawater infiltration on the brittle failure limit

Importance of small earthquakes for stress transfers and earthquake triggering

We estimate the relative importance of small and large earthquakes for static stress changes and for earthquake triggering, assuming that earthquakes are triggered by static stress changes and that earthquakes are located on a fractal network of dimension D. This model predicts that both the number of events triggered by an earthquake of magnitude m and the stress change induced by this earthquake at the location of other earthquakes increase with m as \~10^(Dm/2). The stronger the spatial clustering, the larger the influence of small earthquakes on stress changes at the location of a future event as well as earthquake triggering. If earthquake magnitudes follow the Gutenberg-Richter law with b>D/2, small earthquakes collectively dominate stress transfer and earthquake triggering, because their greater frequency overcomes their smaller individual triggering potential. Using a Southern-California catalog, we observe that the rate of seismicity triggered by an earthquake of magnitude m increases with m as 10^(alpha m), where alpha=1.00+-0.05. We also find that the magnitude distribution of triggered earthquakes is independent of the triggering earthquake magnitude m. When alpha=b, small earthquakes are roughly as important to earthquake triggering as larger ones. We evaluate the fractal correlation dimension of hypocenters D=2 using two relocated catalogs for Southern California, and removing the effect of short-term clustering. Thus D=2alpha as predicted by assuming that earthquake triggering is due to static stress. The value D=2 implies that small earthquakes are as important as larger ones for stress transfers between earthquakes.Comment: 14 pages, 7 eps figures, latex. In press in J. Geophys. Re

Mainshocks are aftershocks of conditional foreshocks: How do foreshock statistical properties emerge from aftershock laws

The inverse Omori law for foreshocks discovered in the 1970s states that the rate of earthquakes prior to a mainshock increases on average as a power law ~ 1/(t_c-t)^p' of the time to the mainshock occurring at t_c. Here, we show that this law results from the direct Omori law for aftershocks describing the power law decay ~ 1/(t-t_c)^p of seismicity after an earthquake, provided that any earthquake can trigger its suit of aftershocks. In this picture, the seismic activity at any time is the sum of the spontaneous tectonic loading and of the activity triggered by all preceding events weighted by their corresponding Omori law. The inverse Omori law then emerges as the expected (in a statistical sense) trajectory of seismicity, conditioned on the fact that it leads to the burst of seismic activity accompanying the mainshock. The often documented apparent decrease of the b-value of the GR law at the approach to the main shock results straightforwardly from the conditioning of the path of seismic activity culminating at the mainshock. In the space domain, we predict that the phenomenon of aftershock diffusion must have its mirror process reflected into an inward migration of foreshocks towards the mainshock. In this model, foreshock sequences are special aftershock sequences which are modified by the condition to end up in a burst of seismicity associated with the mainshock.Comment: Latex document of 35 pages, 10 figure

Melanoma cells break down LPA to establish local gradients that drive chemotactic dispersal.

The high mortality of melanoma is caused by rapid spread of cancer cells, which occurs unusually early in tumour evolution. Unlike most solid tumours, thickness rather than cytological markers or differentiation is the best guide to metastatic potential. Multiple stimuli that drive melanoma cell migration have been described, but it is not clear which are responsible for invasion, nor if chemotactic gradients exist in real tumours. In a chamber-based assay for melanoma dispersal, we find that cells migrate efficiently away from one another, even in initially homogeneous medium. This dispersal is driven by positive chemotaxis rather than chemorepulsion or contact inhibition. The principal chemoattractant, unexpectedly active across all tumour stages, is the lipid agonist lysophosphatidic acid (LPA) acting through the LPA receptor LPAR1. LPA induces chemotaxis of remarkable accuracy, and is both necessary and sufficient for chemotaxis and invasion in 2-D and 3-D assays. Growth factors, often described as tumour attractants, cause negligible chemotaxis themselves, but potentiate chemotaxis to LPA. Cells rapidly break down LPA present at substantial levels in culture medium and normal skin to generate outward-facing gradients. We measure LPA gradients across the margins of melanomas in vivo, confirming the physiological importance of our results. We conclude that LPA chemotaxis provides a strong drive for melanoma cells to invade outwards. Cells create their own gradients by acting as a sink, breaking down locally present LPA, and thus forming a gradient that is low in the tumour and high in the surrounding areas. The key step is not acquisition of sensitivity to the chemoattractant, but rather the tumour growing to break down enough LPA to form a gradient. Thus the stimulus that drives cell dispersal is not the presence of LPA itself, but the self-generated, outward-directed gradient

Seismicity rate immediately before and after mainshock rupture from high-frequency waveforms in Japan

International audienceWe analyze seismicity rate immediately before and after 82 mainshocks with the magnitudes ranging from 3 to 5 using waveforms recorded by the Hi-net borehole array in Japan. By scrutinizing high-frequency signals, we detect ~5 times as many aftershocks in the first 200 s as in the Japan Meteorological Agency catalogue. After correcting for the changing completeness level immediately after the mainshock, the aftershock rate shows a crossover from a slower decay with an Omori's law exponent p = 0.58±0.08 between 20 and 900 s after the mainshock, to a faster decay with p = 0.92±0.04 after 900 s. The foreshock seismicity rate follows an inverse Omori's law with p = 0.73±0.07 from several tens of days up to several hundred seconds before the mainshock. The seismicity rate in the 200 s immediately before the mainshock appears steady with p = 0.36±0.45. These observations can be explained by the epidemic-type aftershock sequence (ETAS) model, and the rate-and-state model for a heterogeneous stress field on the mainshock rupture plane. Alternatively, non-seismic stress changes near the source region, such as episodic aseismic slip, or pore fluid pressure fluctuations, may be invoked to explain the observation of small p values immediately before and after the mainshock