Late Spring and Summer Phytoplankton Community Dynamics on Georges Bank with Emphasis on Diatoms, Alexandrium SPP., and other Dinoflagellates

Georges Bank is a highly productive continental shelf system in the Northwest Atlantic that has historically supported a rich fishery. Part of that productivity stems from annual spring diatom bloom, which is followed by post-bloom populations of flagellates, including the toxic dinoflagellate Alexandrium spp., responsible for paralytic shellfish poisoning. While the general oceanography of Georges Bank has been well studied, far less is known about phytoplankton community dynamics or even basic species distributions and abundance. This thesis is driven in part by the possible competitive interactions among species of phytoplankton which are thought to influence Alexandrium blooms on the Bank. I examined the distribution, abundance, and succession patterns of the major species groups of diatoms, dinoflagellates, and nanoplankton on Georges Bank from late spring through summer 2008 (late April, May and June). Those results were related to dissolved inorganic nutrients, total and size-fractioned chlorophyll concentrations, and hydrography (temperature and salinity). The late April phytoplankton community was predominantly diatoms, mainly Skeletonema spp., Thalassiosira spp., Coscinodiscus spp., and Chaetoceros spp. with cell densities of \u3e 200,000 cells L 1; reduced nutrient concentrations over most of the Bank, except the northern portions, indicated that this marked the end of the spring bloom. Lower nitrate (and silicate) concentrations in May, and patches of slightly elevated ammonium, were supporting a dinoflagellate population with high cell densities of Alexandrium spp. (up to 13,000 cells L 1). Diatom cell densities were fewer than 40,000 cells L 1 and did not overlap spatially with the high cell densities of Alexandrium spp. Localized patches of elevated silicate (from regeneration) observed in late May cruise appeared to support a post-bloom, summer diatom community (\u3e 180,000 cells L 1), of species of Leptocylindrus spp., Dactyliosolen spp., and Guinardia flaccida. Continued reduction of nutrient concentrations in late June was accompanied by a shift in the phytoplankton community. The Alexandrium cell densities had dropped by late June, and species of heterotrophic and mixotrophic dinofiagellates, notably Polykrikos spp., Gyrodinium spp., Gymnodinium spp., and Prorocentrum spp. increased in abundance. Ingested cells were visible in the preserved samples of Gyrodinium spp. and Polykrikos spp. from late June, suggesting an interaction between the heterotrophic component of the phytoplankton community and the declining Alexandrium spp. bloom. Multivariate statistical analyses of phytoplankton groups and sampling stations revealed distinct groupings of diatom and dinoflagellate taxa based on similarities in abundance and distribution on Georges Bank, throughout the late spring and summer, which could often be linked to particular oceanographic processes. Spatial and temporal trends with respect to these statistical groups suggest that interesting succession patterns exist in the phytoplankton community on Georges Bank and may be the result of biological interactions between and among the major groups (i.e. diatoms and dinoflagellates). Preliminary laboratory experiments using Alexandrium fundyense and the diatom Ditylum brightwellii suggested a competitive interaction between diatoms and dinoflagellates, which argues for further study

Breaking Art Apart

The human figure, allegory, myth, and the appropriation of other artist’s compositions are elements in my work. I aim to update traditional stories to conform to contemporary times and culture. In addition, I am striving to create a new method to visually express figurative storytelling. Breaking from the traditional flat painting surface, I use multiple shaped panels. The surface is broken into different shaped panels at varying distances from each other and from the wall. This allows for more exploration into shape and negative space while depicting the dramatic height of a story. As part of this method, my paintings explore the discrete nature of human vision, or how we focus on individual parts of a scene while the brain filters the gestalt

Multifractal magnetic susceptibility distribution models of hydrothermally altered rocks in the Needle Creek Igneous Center of the Absaroka Mountains, Wyoming

International audienceMagnetic susceptibility was measured for 700 samples of drill core from thirteen drill holes in the porphyry copper-molybdenum deposit of the Stinkingwater mining district in the Absaroka Mountains, Wyoming. The magnetic susceptibility measurements, chemical analyses, and alteration class provided a database for study of magnetic susceptibility in these altered rocks. The distribution of the magnetic susceptibilities for all samples is multi-modal, with overlapping peaked distributions for samples in the propylitic and phyllic alteration class, a tail of higher susceptibilities for potassic alteration, and an approximately uniform distribution over a narrow range at the highest susceptibilities for unaltered rocks. Samples from all alteration and mineralization classes show susceptibilities across a wide range of values. Samples with secondary (supergene) alteration due to oxidation or enrichment show lower susceptibilities than primary (hypogene) alteration rock. Observed magnetic susceptibility variations and the monolithological character of the host rock suggest that the variations are due to varying degrees of alteration of blocks of rock between fractures that conducted hydrothermal fluids. Alteration of rock from the fractures inward progressively reduces the bulk magnetic susceptibility of the rock. The model introduced in this paper consists of a simulation of the fracture pattern and a simulation of the alteration of the rock between fractures. A multifractal model generated from multiplicative cascades with unequal ratios produces distributions statistically similar to the observed distributions. The reduction in susceptibility in the altered rocks was modelled as a diffusion process operating on the fracture distribution support. The average magnetic susceptibility was then computed for each block. For the purpose of comparing the model results with observation, the simulated magnetic susceptibilities were then averaged over the same interval as the measured data. Comparisons of the model and data from drillholes show good but not perfect agreement

Understanding the communicative processes of baby boomer women adjusting to retirement: Connecting micro and macro discourses

Baby Boomers are changing the face of retirement in the United States. For example, retirement traditionally refers to the time when an individual who has worked full-time for the majority of her life chooses to entirely and permanently exit the workforce, but now includes a range of formations (e.g., bridge employment). Baby Boomer women are most affected by this “new” retirement because they have worked a broader range of jobs for longer periods of time than ever before. Transitioning to retirement implicates processes of adjusting beyond just a change in one’s employment status as retirees potentially confront instrumental (e.g., where to live), relational (e.g., changes in routine with spouse/partner) and identity (e.g., aging) shifts. This study pairs organizational discourse perspectives and the normative theory of social support to analyze micro and macro discourses about how Baby Boomer women experience the transition to retirement. Regarding micro-discourses, retirees often experience retirement as part of a couple since most have a self-defined partner. Hence, retirement involves communicative processes of adjusting as partners (re)negotiate roles and behaviors that have existed for many years. Regarding macro-discourses, the unprecedented nature of today’s retirement likely encourages women and their partners to look to and be influenced by media representations of retirement and respond to these representations in a range of ways. The multilevel nature of this project necessitated two types of data. Semi-structured interviews with women who retired in the past three years and their partners represented micro level discourses (N = 35; 19 females, 16 males), whereas media texts from sources like AARP The Magazine reflected macro level Discourses (N = 100). Analysis techniques included grounded theory methods, thematic analysis, dyadic qualitative data analysis methods, as well as innovative approaches for linking multiple levels of data. Findings from interviews resulted in a framework which reveals that retirement becomes “meaning-ful” for women when situated between their pre-retirement lives and the uncertainty that surrounds the future. Seven aspects become salient during the transition to retirement including (a) finances, (b) how to spend time, (c) where to live, (d) changes in friendship relationships, (e) valuing relationships with family members, (f) loss of professional identity, and (g) age/aging. Each of these areas implicates instrumental, relational, and identity meanings. Analysis of interviews with men does not fit the framework developed from women’s interviews, suggesting the gendered nature of retirement. Discourses associated with the transition to retirement in media texts included: (a) the “new” retirement, (b) finances in retirement, (c) you need to stay physically, mentally, and socially active in retirement, (d) retirees relocate and you probably should, too, and (e) aging in America. Tensions emerged between Discourses. In addition, most media texts did not articulate ways that forms of difference (e.g., gender) influence retirement. In terms of exploring the transition to retirement as individual and/or dyadic, Discourses tended to emphasize individual aspects while participants themselves framed it as both individual and dyadic. Indeed, variation in how couples treated relevant issues resulted in four couple types (individual decision/individual transition, dyadic decision/individual transition, individual decision/dyadic transition, dyadic decision/dyadic transition). Moreover, four dilemmas emerged that reflect participants’ attempts to pursue conflicting goals via interaction with their spouses: (a) I love you but I don’t want to spend (all) my time with you, (b) Retirement is enjoyable for everyone but you aren’t enjoying it, (c) (Good) parents to X in retirement but you’re doing Y, and (d) Retirement means freedom from work but you’re still “working.” Couples reported several strategies employed to manage dilemmas. Finally, analysis identified a range of connections between levels of D/discourse such as “The lucky ones: Baby Boomers with enough money to retire,” which suggests alignment between D/discourses that financial preparation for retirement is an individual responsibility. These connections tap into broader dialectics (e.g., certainty v. uncertainty). Theoretical, methodological, and practical implications of these findings are discussed and future research directions are noted

Facilitating support groups for siblings of children with neurodevelopmental disorders using audioconferencing: a longitudinal feasibility study

Background: Siblings of children with chronic illness and disabilities are at increased risk of negative psychological effects. Support groups enable them to access psycho-education and social support. Barriers to this can include the distance they have to travel to meet face-to-face. Audio-conferencing, whereby three or more people can connect by telephone in different locations, is an efficient means of groups meeting and warrants exploration in this healthcare context. This study explored the feasibility of audio-conferencing as a method of facilitating sibling support groups. Methods: A longitudinal design was adopted. Participants were six siblings (aged eight to thirteen years) and parents of children with complex neurodevelopmental disorders attending the Centre for Interventional Paediatric Psychopharmacology (CIPP). Four of the eight one-hour weekly sessions were held face-to-face and the other four using audio-conferencing. Pre- and post-intervention questionnaires and interviews were completed and three to six month follow-up interviews were carried out. The sessions were audio-recorded, transcribed and thematic analysis was undertaken. Results: Audio-conferencing as a form of telemedicine was acceptable to all six participants and was effective in facilitating sibling support groups. Audio-conferencing can overcome geographical barriers to children being able to receive group therapeutic healthcare interventions such as social support and psycho-education. Psychopathology ratings increased post-intervention in some participants. Siblings reported that communication between siblings and their family members increased and siblings’ social network widened. Conclusions: Audio-conferencing is an acceptable, feasible and effective method of facilitating sibling support groups. Siblings’ clear accounts of neuropsychiatric symptoms render them reliable informants. Systematic assessment of siblings’ needs and strengthened links between Child and Adolescent Mental Health Services, school counsellors and young carers groups are warranted

Gravity signals at the Geysers geothermal system

Journal ArticleThree high-precision gravity and GPS surveys have been conducted over The Geysers geothermal reservoir and surrounding area. These surveys, in September 2000, April 2001, and September 2001, provide an initial baseline for future imaging studies of spatial mass changes from the Santa Rosa Effluent Pipeline currently under construction. Analysis of the three surveys provides a measure of the seasonal and annual gravity and deformation signals currently occurring at The Geysers. GPS results show an average subsidence of 3±2 cm over the production field from September 2000 to April 2001, although some stations have significant deviations from this average

An air suspension to demonstrate the properties of torsion balances with fibers of zero length

We report on the design and characterisation of an air-bearing suspension that has been constructed to highlight the properties of torsion balances with fibres of zero length. A float is levitated on this suspension and its rotational and translational motion in the horizontal plane of the laboratory is controlled using magnetic actuators. We demonstrate the in-situ electromagnetic tuning of the float's centre-of-buoyancy to an accuracy of $\pm$0.3 mm, which was limited by the noise in the air bearing. The rotational stiffness of the float, which is approximately zero by design, was also measured. We compare the observed behaviour of the float with the predictions of a detailed model of the statics of the float-actuator system. Finally, we briefly discuss the application of these ideas and results to the construction of sensitive devices for the measurement of weak forces with short ranges.Comment: 7 pages, 9 figure

Techniques, analysis, and noise in a Salt Lake Valley 4D gravity experiment

Journal ArticleRepeated high-precision gravity measurements using an automated gravimeter and analysis of time series of 1-Hz samples allowed gravity measurements to be made with an accuracy of 5 μGal or better. Nonlinear instrument drift was removed using a new empirical staircase function built from multiple station loops. The new technique was developed between March 1999 and September 2000 in a pilot study conducted in the southern Salt Lake Valley along an east-west profile of eight stations from the Wasatch Mountains to the Jordan River

Racketeer Influenced and Corrupt Organizations (RICO): Basic Concepts - Criminal and Civil Remedies

This article will present a brief overview of the legislative history of RICO, the Racketeer Influenced and Corrupt Organizations, and its structure, including its standards and basic concepts. The article will then consider the criminal sanctions authorized under RICO and discuss specific aspects of the RICO civil suit as well as some of the problems that may be expected to arise in it. The objective of the article is to provide the reader with a short introduction to RICO, one of the most sophisticated statutes ever enacted by Congress