106 research outputs found
Low-Frequency hybrid earthquakes near a magma chamber in Afar: quantifying path effects
No full textAreas of active volcanism contain elaborate velocity structures that complicate interpretations of earthquake source mechanisms. We examine the spectral characteristics of 805 earthquakes that immediately followed a large volume basaltic dike intrusion and associated silicic flank eruption of Dabbahu volcano in the Afar Depression as recorded on near-source seismometers. We use these results to quantify the contribution of scattering and attenuation to the observed spectra of low-frequency hybrid and volcano-tectonic earthquake clusters from beneath Dabbahu volcano and around the dike zone. We find strong variations in the signal amplitude and frequency content of earthquakes recorded at stations separated by as little as 2 km, caused by preferential attenuation of high frequencies depending on the vantage point. These observations imply that there are large impedance contrasts near the cooling, solidifying, and recently intruded dike. We estimate the intrinsic absorption attenuation coefficient, QI, and inverse scattering length, g0, averaged over a 300-sq-km area beneath Dabbahu. Our results are consistent with the highest attenuation coefficients from studies of volcanic provinces in Italy (QI-1 ? 0.02, g0?0.1 km-1 for a signal at 2 Hz). The magnitude of these two parameters indicates there are large impedance contrasts present in the area due to the recent intrusion of magma and associated fracturing
The relationship between depression and chronotype: A longitudinal assessment during childhood and adolescence
No full textBackground/Objective
During adolescence, chronotype shifts towards “eveningness.” “Eveningness” is related to negative physical and mental health outcomes. Little is known about what influences the shift in chronotype beyond pubertal status. The current study examined the influence of earlier depression predicting later individual differences in adolescent chronotype, accounting for pubertal status, and the prospective prediction of later increases in depression from earlier chronotype.
Methods
Youth (age M=12.06, SD=2.35; 56.5% girls) from the community completed repeated assessments of depression, including both self-reports (14 assessments) and diagnostic interviews (8 assessments), over a 48-month period. At the 36-month time-point, participants completed chronotype and pubertal development measures. Regression and ANOVA analyses examined: (1) the influence of earlier depression levels (baseline to 36-months) upon chronotype, and (2) chronotype (at 36 months) upon later depression (48 months).
Results
Youth with higher earlier depression symptoms (β=-.347, p<.001) and history of depression diagnosis (β=-.13, p=.045) showed a greater eveningness preference controlling for pubertal status, age and gender. Further, depression diagnosis history interacted with pubertal status to predict chronotype: (F(1,243)=4.171, p=.045) such that the influence of depression on chronotype was greatest among postpubertal youth (t=3.271, p=.002). Chronotype (greater eveningness preference) predicted prospective increases in depression symptoms (β=-.16, p=.03) and onset of depressive episode (b=-.085, OR=.92, p=.03) one year later.
Conclusion
Depression, experienced earlier in life, predicts greater preference for eveningness, especially among postpubertal youth. In turn, later depression is predicted by evening preference. These findings suggest the reciprocal interplay between mood and biological rhythms, especially depression and chronotype, during adolescence.Submission published under a 24 month embargo labeled 'Closed Access', the embargo will last until 2019-12-01The student, Dustin Haraden, accepted the attached license on 2017-12-12 at 16:34.The student, Dustin Haraden, submitted this Thesis for approval on 2017-12-12 at 16:40.This Thesis was approved for publication on 2017-12-13 at 08:22.DSpace SAF Submission Ingestion Package generated from Vireo submission #11961 on 2018-03-13 at 10:38:25Made available in DSpace on 2018-03-13T17:35:57Z (GMT). No. of bitstreams: 2
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Previous issue date: 2017-12-13Embargo set by: Seth Robbins for item 105503
Lift date: 2020-03-13T17:36:05Z
Reason: Author requested closed access (OA after 2yrs) in Vireo ETD systemLimited Restriction Lifted for Item 105503 on 2020-03-14T09:15:25Z
Supplemental material2 - Supplemental material for Building and Maintaining a Citizen Science Network With Fishermen and Fishing Communities Post Deepwater Horizon Oil Disaster Using a CBPR Approach
No full textSupplemental material, Supplemental material2 for Building and Maintaining a Citizen Science Network With Fishermen and Fishing Communities Post Deepwater Horizon Oil Disaster Using a CBPR Approach by Academic Authors: John Sullivan, Sharon Croisant, Marilyn Howarth, Gilbert T. Rowe, Harshica Fernando, Amanda Phillips-Savoy, Dan Jackson, John Prochaska, Ghulam A. S. Ansari, Trevor M. Penning, Cornelis Elferink and Community Partner Authors: Louisiana Environmental Action Network, United Houma Nation, Bayou Interfaith Shared Community Organizing, Dustin Nguyen-Vietnamese Community Partner, Center for Environmental & Economic Justice, and Alabama Fisheries CooperativeProject Community Scientist Author: Wlima Subra in NEW SOLUTIONS: A Journal of Environmental and Occupational Health Policy</p
Supplemental material1 - Supplemental material for Building and Maintaining a Citizen Science Network With Fishermen and Fishing Communities Post Deepwater Horizon Oil Disaster Using a CBPR Approach
No full textSupplemental material, Supplemental material1 for Building and Maintaining a Citizen Science Network With Fishermen and Fishing Communities Post Deepwater Horizon Oil Disaster Using a CBPR Approach by Academic Authors: John Sullivan, Sharon Croisant, Marilyn Howarth, Gilbert T. Rowe, Harshica Fernando, Amanda Phillips-Savoy, Dan Jackson, John Prochaska, Ghulam A. S. Ansari, Trevor M. Penning, Cornelis Elferink and Community Partner Authors: Louisiana Environmental Action Network, United Houma Nation, Bayou Interfaith Shared Community Organizing, Dustin Nguyen-Vietnamese Community Partner, Center for Environmental & Economic Justice, and Alabama Fisheries CooperativeProject Community Scientist Author: Wlima Subra in NEW SOLUTIONS: A Journal of Environmental and Occupational Health Policy</p
Supplemental material4 - Supplemental material for Building and Maintaining a Citizen Science Network With Fishermen and Fishing Communities Post Deepwater Horizon Oil Disaster Using a CBPR Approach
No full textSupplemental material, Supplemental material4 for Building and Maintaining a Citizen Science Network With Fishermen and Fishing Communities Post Deepwater Horizon Oil Disaster Using a CBPR Approach by Academic Authors: John Sullivan, Sharon Croisant, Marilyn Howarth, Gilbert T. Rowe, Harshica Fernando, Amanda Phillips-Savoy, Dan Jackson, John Prochaska, Ghulam A. S. Ansari, Trevor M. Penning, Cornelis Elferink and Community Partner Authors: Louisiana Environmental Action Network, United Houma Nation, Bayou Interfaith Shared Community Organizing, Dustin Nguyen-Vietnamese Community Partner, Center for Environmental & Economic Justice, and Alabama Fisheries CooperativeProject Community Scientist Author: Wlima Subra in NEW SOLUTIONS: A Journal of Environmental and Occupational Health Policy</p
Supplemental material3 - Supplemental material for Building and Maintaining a Citizen Science Network With Fishermen and Fishing Communities Post Deepwater Horizon Oil Disaster Using a CBPR Approach
No full textSupplemental material, Supplemental material3 for Building and Maintaining a Citizen Science Network With Fishermen and Fishing Communities Post Deepwater Horizon Oil Disaster Using a CBPR Approach by Academic Authors: John Sullivan, Sharon Croisant, Marilyn Howarth, Gilbert T. Rowe, Harshica Fernando, Amanda Phillips-Savoy, Dan Jackson, John Prochaska, Ghulam A. S. Ansari, Trevor M. Penning, Cornelis Elferink and Community Partner Authors: Louisiana Environmental Action Network, United Houma Nation, Bayou Interfaith Shared Community Organizing, Dustin Nguyen-Vietnamese Community Partner, Center for Environmental & Economic Justice, and Alabama Fisheries CooperativeProject Community Scientist Author: Wlima Subra in NEW SOLUTIONS: A Journal of Environmental and Occupational Health Policy</p
Influences of host community characteristics on Borrelia burgdorferi infection prevalence in Blacklegged ticks
No full textLyme disease is a major vector-borne bacterial disease in the USA. The disease is caused by Borrelia burgdorferi, and transmitted among hosts and humans, primarily by blacklegged ticks (Ixodes scapularis). The ~25 B. burgdorferi genotypes, based on genotypic variation of their outer surface protein C (ospC), can be phenotypically separated as strains that primarily cause human diseases – human invasive strains (HIS) – or those that rarely do – and are non-randomly associated with host species. The goal of this study was to examine the extent to which phenotypic outcomes of B. burgdorferi could be explained by the host communities fed upon by blacklegged ticks. In 2006 and 2009, we determined the host community composition based on abundance estimates of the vertebrate hosts, and collected host-seeking nymphal ticks in 2007 and 2010 to determine the ospC genotypes within infected ticks. We regressed instances of B. burgdorferi phenotypes on site-specific characteristics of host communities by constructing Bayesian hierarchical models that properly handled missing data. The models provided quantitative support for the relevance of host composition on Lyme disease risk pertaining to B. burgdorferi prevalence (i.e., overall nymphal infection prevalence, or NIPAll) and HIS prevalence among the infected ticks (NIPHIS). In 2006, we found positive associations of the relative abundances of mice, of chipmunks, and of shrews with NIPAll. We also found positive associations of NIPHIS with shrews, and with host community diversity (H’), but negative associations with mice, and with chipmunks. In 2009, the relative abundance of mice showed a positive association with NIPAll, whereas the relative abundance of shrews and of H’ showed a negative association. With NIPHIS, only H’ showed a positive association, whereas the relative abundances of mice, of chipmunks, and of shrews, had negative associations. Our study highlights the variability between two years in the effects of host composition on B. burgdorferi genotypes. More importantly, our results highlight how disease risk inference, based on the role of host community, changes when we examine risk overall or at the phenotypic level. Long-term studies will be necessary to detect any consistent effects of host community composition on genotypic variation in the Lyme disease spirochetes
Morphology of mitochondria and cell respiration,pt.1.
No full textTo reveal the mechanism of liver damage by taking CCl4 the author observed the liver tissues from rats at 1.5, 5, 6, 10, 17, 20, and 22 hours after the CCl4 administration, both by light microscope and electron-microscope. 1. Light microscope observation revealed the swelling of liver cells in the carly stage, the appearance of centrolobular fatty degeneration, focal degeneration area and the appearance of balloon cells, with the circulatory disturbances in accompanying stages and hemorrhage in the later stage. 2. Electron-microscope observation revealed the swelling of mitochondria, appearance of the files of thin ER's in the early stage and the regeneration and degeneration of mitochondria with an increase of microbodies in number. Fat droplets are developed from small ones probably from some microbodies without correlation with mitochondria. 3. From these observations the author is of the opinion that CCl4 arrests the cells at first inducing the swelling of cells and their mitochondria, but later the degenerative changes will become severe being complicated by the anoxia which is induced by the circulatory disturbances caused by the compression of vessels with the swollen cells.</p
Repetition Blindness for Emotion Words: Exploring Interactions Between Valence and Arousal
No full textR code for manuscript that I am a co-author on with Dr. Tina Sutto
The first rolling load simulator (ROLLS) for testing bridges in Canada and its application on a full-scale precast box girder
No full textThis paper describes the development of a unique rolling load simulator (ROLLS) for testing bridge superstructure with a footprint up to 4 m ×17 m, and its first application to test a full-scale 1220 mm ×900 mm ×16000 mm B900 prestressed concrete box girder. This facility at Queen’s University in Kingston, Ontario, is the first of its kind in Canada. ROLLS can apply cyclic loading in a controlled laboratory environment, under realistic highway scale ‘rolling wheel loads’, in lieu of the conventional ‘pulsating stationary loads’. It has two half-axles of a large tandem, each comprising a dual 1140 mm diameter air-inflated tires spaced at either 1.2 or 2.4 m. Each half-axle can apply up to 125 kN, representing the heaviest half-axle load of the CL-625 design truck of the Canadian Highway Bridge Design Code (CHBDC). The maximum travel range and speed are 14.9 m and 6 m/s, respectively. A case study involving analysis of a bridge with eight adjacent B900 box girders of 27.6 m span was carried out prior to experimentally testing one of the girders using ROLLS. Load distribution analyses were conducted using both (i) a finite element model of the full bridge under various CL-625 truck loading configurations and (ii) the CHBDC load distribution method, and both agreed well. Scaling analysis of the girder load share was then conducted to account for shortening it to 16 m to fit in the laboratory, resulting in two-115 kN ROLLS design loads, 1.2 m apart. Multiple passes were conducted at various loads of 40%–100% of the design load, at speeds of 1–5 m/s to examine the machine and girder behaviours. It was found that the applied load fluctuates by less than 10% of full capacity and a 0.13 s/cycle time lag occurs. The measured girder deflection and elastic strains were 11%–20% lower than predicted theoretically. With the two half-axles assembly spaced at 1.2 m, the apparatus has the ability to complete three million cycles in approximately 4.5 months if ran continuously at 5 m/s.The accepted manuscript in pdf format is listed with the files at the bottom of this page. The presentation of the authors' names and (or) special characters in the title of the manuscript may differ slightly between what is listed on this page and what is listed in the pdf file of the accepted manuscript; that in the pdf file of the accepted manuscript is what was submitted by the author
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