Shallow stratigraphic control on pockmark distribution in north temperate estuaries

This paper is not subject to U.S. copyright. The definitive version was published in Marine Geology 329-331 (2012): 34-45, doi:10.1016/j.margeo.2012.09.006.Pockmark fields occur throughout northern North American temperate estuaries despite the absence of extensive thermogenic hydrocarbon deposits typically associated with pockmarks. In such settings, the origins of the gas and triggering mechanism(s) responsible for pockmark formation are not obvious. Nor is it known why pockmarks proliferate in this region but do not occur south of the glacial terminus in eastern North America. This paper tests two hypotheses addressing these knowledge gaps: 1) the region's unique sea-level history provided a terrestrial deposit that sourced the gas responsible for pockmark formation; and 2) the region's physiography controls pockmarks distribution. This study integrates over 2500 km of high-resolution swath bathymetry, Chirp seismic reflection profiles and vibracore data acquired in three estuarine pockmark fields in the Gulf of Maine and Bay of Fundy. Vibracores sampled a hydric paleosol lacking the organic-rich upper horizons, indicating that an organic-rich terrestrial deposit was eroded prior to pockmark formation. This observation suggests that the gas, which is presumably responsible for the formation of the pockmarks, originated in Holocene estuarine sediments (loss on ignition 3.5–10%), not terrestrial deposits that were subsequently drowned and buried by mud. The 7470 pockmarks identified in this study are non-randomly clustered. Pockmark size and distribution relate to Holocene sediment thickness (r2 = 0.60), basin morphology and glacial deposits. The irregular underlying topography that dictates Holocene sediment thickness may ultimately play a more important role in temperate estuarine pockmark distribution than drowned terrestrial deposits. These results give insight into the conditions necessary for pockmark formation in nearshore coastal environments.Graduate support for Brothers came from a Maine Economic Improvement Fund Dissertation Fellowship

The Grizzly, February 15, 1985

USGA Reschedules Election • Japanese Studies Prof. Returns to U.C. • UC Retention Rate Above National Average • Without Reform, Second Election Doomed to Failure • U.C. Contributes to Local Secondary Education: Need for Tutors May Grow • College Students Have Trouble Managing Money, Survey Shows • Campus Life Surveys Possible Displacements • Grapplers Keep Winning: Wiehler Notches 14-second Fall • Senior Matmen Get Last Shot at MAC Title • Ververeli Operates on the Mats for Now • Mers Dunk Dips • Mermaids Win Three, Lose One • UC Grad Writes Book • B-ball Drops Two • Lady Hoopsters\u27 Losing Ways Continuehttps://digitalcommons.ursinus.edu/grizzlynews/1133/thumbnail.jp

Hybrid kernelised expectation maximisation for Bremsstrahlung SPECT reconstruction in SIRT with 90Y micro-spheres

BACKGROUND: Selective internal radiation therapy with Yttrium-90 microspheres is an effective therapy for liver cancer and liver metastases. Yttrium-90 is mainly a high-energy beta particle emitter. These beta particles emit Bremsstrahlung radiation during their interaction with tissue making post-therapy imaging of the radioactivity distribution feasible. Nevertheless, image quality and quantification is difficult due to the continuous energy spectrum which makes resolution modelling, attenuation and scatter estimation challenging and therefore the dosimetry quantification is inaccurate. As a consequence a reconstruction algorithm able to improve resolution could be beneficial. METHODS: In this study, the hybrid kernelised expectation maximisation (HKEM) is used to improve resolution and contrast and reduce noise, in addition a modified HKEM called frozen HKEM (FHKEM) is investigated to further reduce noise. The iterative part of the FHKEM kernel was frozen at the 72nd sub-iteration. When using ordered subsets algorithms the data is divided in smaller subsets and the smallest algorithm iterative step is called sub-iteration. A NEMA phantom with spherical inserts was used for the optimisation and validation of the algorithm, and data from 5 patients treated with Selective internal radiation therapy were used as proof of clinical relevance of the method. RESULTS: The results suggest a maximum improvement of 56% for region of interest mean recovery coefficient at fixed coefficient of variation and better identification of the hot volumes in the NEMA phantom. Similar improvements were achieved with patient data, showing 47% mean value improvement over the gold standard used in hospitals. CONCLUSIONS: Such quantitative improvements could facilitate improved dosimetry calculations with SPECT when treating patients with Selective internal radiation therapy, as well as provide a more visible position of the cancerous lesions in the liver

The Grizzly, February 1, 1985

Ursinus Dodges Enrollment Drought • USGA Candidate Petitions Due • Letter: Spanish Prof Encounters Alumnus • New Fogerty Album a Hit • The Beat Goes Public • pro Theatre • Swimmin\u27 Women Boost Record to 3-2 • Grapplers Win 6, Lose 1 • Injured Matman Won\u27t Quit • Mers and Vers Compete During Break • Men\u27s B-ball Defeat Moravian • Lady Bears Trying to Pull Out of Slump • Chinese Star Talks to Bootershttps://digitalcommons.ursinus.edu/grizzlynews/1131/thumbnail.jp

Forested plant associations of the Colville National Forest

A classification of forest vegetation is presented for the Colville National Forest in northeastern Washington State. It is based on potential vegetation with the plant association as the basic unit. The classification is based on a sample of approximately 229 intensive plots and 282 reconnaisance plots distributed across the forest from 1980 to 1983. The hierarchical classification includes 5 forest tree series and 39 plant associations or community types. Diagnostic keys are presented for each tree series and plant association or community type. Descriptions include information about plant association or community species composition, occurrences, distribution, environment, soils, forest productivity, management implications and relations to other vegetation classifications. Background information is also presented on the ecology, geology, soils, climate, and fire history of the Colville National Forest.Keywords: Vegetation classification, climax plant communities, potential vegetation, plant association, vegetation series, forest ecology, fire, wildife, range, northeastern Washington

Early (and Later) LHC Search Strategies for Broad Dimuon Resonances

Resonance searches generally focus on narrow states that would produce a sharp peak rising over background. Early LHC running will, however, be sensitive primarily to broad resonances. In this paper we demonstrate that statistical methods should suffice to find broad resonances and distinguish them from both background and contact interactions over a large range of previously unexplored parameter space. We furthermore introduce an angular measure we call ellipticity, which measures how forward (or backward) the muon is in eta, and allows for discrimination between models with different parity violation early in the LHC running. We contrast this with existing angular observables and demonstrate that ellipticity is superior for discrimination based on parity violation, while others are better at spin determination.Comment: 31 pages, 19 figures. References added, minor modifications made to section

The Grizzly, December 7, 1984

Campus Life Considers Alternative Housing • Meunch Proposes RA Pay Raise • French Department Plans Summer Study Aboard • Campus Enjoys Third Pub Night • Phone Jacks in Old Men\u27s by Spring Semester, Kane Says • College Bowl Enters Sixth Week • Grapplers Take Second at LVI • Men\u27s B-ball Jumps to 4-0 • Women\u27s B-ball Loses to Swarthmore • Fencing Club Co-sponsors Tourney • Mermen Win Big • Men\u27s Track Begins Indoor Season • Gymnasts Win Openerhttps://digitalcommons.ursinus.edu/grizzlynews/1130/thumbnail.jp

Triple modality image reconstruction of PET data using SPECT, PET, CT information increases lesion uptake in images of patients treated with radioembolization with [Formula: see text] micro-spheres.

PURPOSE: Nuclear medicine imaging modalities like computed tomography (CT), single photon emission CT (SPECT) and positron emission tomography (PET) are employed in the field of theranostics to estimate and plan the dose delivered to tumors and the surrounding tissues and to monitor the effect of the therapy. However, therapeutic radionuclides often provide poor images, which translate to inaccurate treatment planning and inadequate monitoring images. Multimodality information can be exploited in the reconstruction to enhance image quality. Triple modality PET/SPECT/CT scanners are particularly useful in this context due to the easier registration process between images. In this study, we propose to include PET, SPECT and CT information in the reconstruction of PET data. The method is applied to Yttrium-90 ([Formula: see text]Y) data. METHODS: Data from a NEMA phantom filled with [Formula: see text]Y were used for validation. PET, SPECT and CT data from 10 patients treated with Selective Internal Radiation Therapy (SIRT) were used. Different combinations of prior images using the Hybrid kernelized expectation maximization were investigated in terms of VOI activity and noise suppression. RESULTS: Our results show that triple modality PET reconstruction provides significantly higher uptake when compared to the method used as standard in the hospital and OSEM. In particular, using CT-guided SPECT images, as guiding information in the PET reconstruction significantly increases uptake quantification on tumoral lesions. CONCLUSION: This work proposes the first triple modality reconstruction method and demonstrates up to 69% lesion uptake increase over standard methods with SIRT [Formula: see text]Y patient data. Promising results are expected for other radionuclide combination used in theranostic applications using PET and SPECT

Most Common Single-Nucleotide Polymorphisms Associated With Rheumatoid Arthritis in Persons of European Ancestry Confer Risk of Rheumatoid Arthritis in African Americans

Objective. Large-scale genetic association studies have identified \u3e20 rheumatoid arthritis (RA) risk alleles among individuals of European ancestry. The influence of these risk alleles has not been comprehensively studied in African Americans. We therefore sought to examine whether these validated RA risk alleles are associated with RA risk in an African American population. Methods. Twenty-seven candidate single-nucleotide polymorphisms (SNPs) were genotyped in 556 autoantibody-positive African Americans with RA and 791 healthy African American control subjects. Odds ratios (ORs) and 95% confidence intervals (95% CIs) for each SNP were compared with previously published ORs for RA patients of European ancestry. We then calculated a composite genetic risk score (GRS) for each individual based on the sum of all risk alleles. Results. Overlap of the ORs and 95% CIs between the European and African American populations was observed for 24 of the 27 candidate SNPs. Conversely, 3 of the 27 SNPs (CCR6 rs3093023, TAGAP rs394581, and TNFAIP3 rs6920220) demonstrated ORs in the opposite direction from those reported for RA patients of European ancestry. The GRS analysis indicated a small but highly significant probability that African American patients relative to control subjects were enriched for the risk alleles validated in European RA patients (P = 0.00005). Conclusion. The majority of RA risk alleles previously validated for RA patients of European ancestry showed similar ORs in our population of African Americans with RA. Furthermore, the aggregate GRS supports the hypothesis that these SNPs are risk alleles for RA in the African American population. Future large-scale genetic studies are needed to validate these risk alleles and identify novel RA risk alleles in African Americans