Active Tectonics In Southern Alaska And The Role Of The Yakutat Block Constrained By Gps Measurements

Thesis (Ph.D.) University of Alaska Fairbanks, 2011GPS data from southern Alaska and the northern Canadian Cordillera have helped redefine the region's tectonic landscape. Instead of a comparatively simple interaction between the Pacific and North American plates, with relative motion accommodated on a single boundary fault, the margin is made up of a number of small blocks and deformation zones with relative motion distributed across a variety of structures. Much of this complexity can be attributed to the Yakutat block, an allochthonous terrane that has been colliding with southern Alaska since the Miocene. This thesis presents GPS data from across the region and uses it to constrain a tectonic model for the Yakutat block collision and its effects on southern Alaska and eastern Canada. The Yakutat block itself moves NNW at a rate of 50 mm/yr. Along its eastern edge, the Yakutat block is fragmenting into small crustal slivers. Part of the strain from the collision is transferred east of the Fairweather -- Queen Charlotte fault system, causing the region inboard of the Fairweather fault to undergo a distinct clockwise rotation into the northern Canadian Cordillera. About 5% of the relative motion is transferred even further east, causing small northeasterly motions well into the northern Cordillera. Further north, the GPS data and model results indicate that the current deformation front between the Yakutat block and southern Alaska runs along the western side of the Malaspina Glacier. The majority of the ~37 mm/yr of relative convergence is accommodated along a narrow band of thrust faults concentrated in the southeastern part of the St. Elias orogen. Near the Bering Glacier, the tectonic regime abruptly changes as crustal thrust faults give way to subduction of the Yakutat block beneath the western St. Elias orogen and Prince William Sound. This change aligns with the Gulf of Alaska shear zone, implying that the Pacific plate is fragmenting in response to the Yakutat collision. The Bering Glacier region is undergoing internal deformation and may represent the final stage of accretion of the Yakutat block sedimentary layers. Further west, modeled block motions suggest the crust is laterally escaping along the Aleutian forearc

Coseismic deformation from the 2002 Denali Fault earthquake: contributions from synthetic aperture radar speckle tracking

Thesis (M.S.) University of Alaska Fairbanks, 2005The technique of speckle tracking can provide coseismic surface offsets for an earthquake in regions where other geodetic data are not available. These offsets can be used to map the surface deformation and create slip distribution models. This thesis uses speckle tracking to study the 2002 Mw7.9 Denali Fault earthquake, with emphasis on the central section of the rupture. The Denali Fault earthquake began with a thrust event on the Susitna Glacier fault before rupturing unilaterally west to east on the Denali and Totschunda faults with overwhelmingly right-lateral strike-slip motion. A slip distribution estimated from a combination of speckle tracking data from the central section of the rupture, GPS data, and geologic data displays highly variable slip, with four major patches of high slip along the Denali fault. Compared to the primarily GPS-derived model of Hreinsdóttir [2005], the combined model is better constrained along the central rupture and predicts slip values much closer to the geologic offset measurements. A significant releasing bend in the fault just west of the pipeline can be correlated to a patch of high slip and the second-largest pulse of moment release along the rupture, suggesting that fault geometry plays an important role in earthquake mechanics.Introduction -- Tectonic background -- Overview of SAR and speckle tracking -- Speckle tracking data -- Data processing -- Coseismic displacements determined from offsets -- 3-D fault model -- Discussion -- Conclusions -- References

Improving Patient Decision-Making in Health Care

Outlines regional variations within Minnesota in rates of patients with similar conditions receiving elective surgery, the concept of shared decision making, treatment choices for eight conditions, and steps for ensuring patients make informed decisions

Planning and Producing Videos: A Two-Part Workshop on Writing Scripts & Making Videos @Your Library

With the advent of YouTube and new digital editing software, it has become easier for libraries to experiment with instruction videos. However, creating the right script to get your message across can be a challenge. This two-part interactive workshop aims to share our video production experience with you. In the first session, the presenters will help you write a script and guide you through the production planning process. In the second session, one script will be videotaped, edited and will be ready to share with students. By the time the workshop is over, each person will have a script that she or he can take back to their campus for actual production. Interactive Sessio

The alpha-effect in cyclic secondary amines: new scaffolds for iminium ion accelerated transformations

Five-membered secondary amine heterocycles containing an α-heteroatom were prepared and shown to be ineffective as catalysts for the iminium ion catalysed Diels–Alder reaction between cinnamaldehyde and cyclopentadiene. Their six-membered counterparts proved to be highly active catalysts. In stark contrast, the catalytic activity observed when comparing the non α-heteroatom cyclic amines proline methyl ester and methyl pipecolinate showed the five-membered ring amine was significantly more active. Concurrent density functional theoretical calculations suggest a rationale for the observed trends in reactivity, highlighting that LUMO activation through an iminium ion intermediate plays a key role in catalytic activity

Use of a cAMP BRET Sensor to Characterize a Novel Regulation of cAMP by the Sphingosine 1-Phosphate/G13 Pathway

Regulation of intracellular cyclic adenosine 3',5'-monophosphate (cAMP) is integral in mediating cell growth, cell differentiation, and immune responses in hematopoietic cells. To facilitate studies of cAMP regulation we developed a BRET (bioluminescence resonance energy transfer) sensor for cAMP, CAMYEL (cAMP sensor using YFP-Epac-RLuc), which can quantitatively and rapidly monitor intracellular concentrations of cAMP in vivo. This sensor was used to characterize three distinct pathways for modulation of cAMP synthesis stimulated by presumed Gs-dependent receptors for isoproterenol and prostaglandin E2. Whereas two ligands, uridine 5'-diphosphate and complement C5a, appear to use known mechanisms for augmentation of cAMP via Gq/calcium and Gi, the action of sphingosine 1-phosphate (S1P) is novel. In these cells, S1P, a biologically active lysophospholipid, greatly enhances increases in intracellular cAMP triggered by the ligands for Gs-coupled receptors while having only a minimal effect by itself. The enhancement of cAMP by S1P is resistant to pertussis toxin and independent of intracellular calcium. Studies with RNAi and chemical perturbations demonstrate that the effect of S1P is mediated by the S1P2 receptor and the heterotrimeric G13 protein. Thus in these macrophage cells, all four major classes of G proteins can regulate intracellular cAMP