Long-Period Seismicity At Shishaldin Volcano, Alaska

Thesis (Ph.D.) University of Alaska Fairbanks, 2006Since it last erupted in 1999, Shishaldin Volcano, Aleutian Islands, Alaska, has been characterized by a continuous and extremely high level of seismicity. The activity consists of many hundreds to thousands long-period (LP; 1-2 Hz) earthquakes per day. The rate of one LP event every 0.5-5 minutes has remained more or less constant for the last 7 years. A high rate of LP seismicity has been associated with pre-eruptive activity at many other volcanoes presented in the volcano seismology literature. Shishaldin, however, shows no other signs of volcanic unrest except for a ~200 m high steam plume that nearly always emanates from the volcano's summit and occasional weak thermal anomalies observed in satellite imagery. This thesis investigates the nature of Shishaldin's unusual volcanic behavior, and provides a case-study that mainly focuses on seismic data recorded by the short-period monitoring network surrounding the volcano, but also integrates local infrasound data, visual observations and SO2 measurements. The observations suggest a steady-state volcanic process within an open conduit system that is capable of releasing a large amount of energy, approximately equivalent to at least one magnitude 1.8-2.6 earthquake per clay. Shishaldin infrasound signals recorded by a pressure sensor co-located with a seismic instrument are used to confine the source locations of the LP events to a depth of 240 +/- 200 m below the crater rim. The seismo-acoustic data suggest that the LP earthquakes are associated with degassing explosions, created by complex gas volume ruptures from a fluid-air interface. Measurements of the SO2 flux within the puffing summit plume have revealed low values (58 tons/day), suggestive of a hydrothermal system. Four time periods of increased earthquake amplitudes, which each lasted about 1-2 months; have been analyzed. The periods of elevated seismicity are characterized by an abundance of LP events with highly similar waveforms that represent a spatially confined, repetitive, and non-destructive source process. A mechanism, known as choked flow, fulfills all the requirements implied by the observed repeating events and provides a plausible trigger mechanism for Shishaldin's LP events. The observations suggest that the hydrothermal system at Shishaldin is multi-fractured, regulating a pressure gradient within the gas flow through the uppermost conduit

CTX-M-1 and CTX-M-15-producing <i>Escherichia coli</i> in dog faeces from public gardens

BACKGROUND: Extended-spectrum beta-lactamase (ESBL)-producing Escherichia coli are increasingly reported in dogs. The objective of this study was to provide data on the prevalence of ESBL-producing E. coli in dog faecal deposits in public gardens. RESULTS: A total of 209 faecal deposits collected in nine public gardens in Copenhagen, Denmark were screened by selective enrichment followed by plating on MacConkey agar supplemented with cefotaxime. Presumptive ESBL-producing E. coli were confirmed by MALDI-TOF MS and polymerase chain reaction (PCR) for detection of common cefotaxime resistance determinants (bla(TEM), bla(SHV), bla(CTX-M) and bla(CMY-2)). ESBL-producers were further characterized by multilocus sequence typing (MLST) and antimicrobial susceptibility testing using broth microdilution. Plasmids harbouring ESBL genes were characterized by S1 nuclease pulsed field gel electrophoresis, PCR-based replicon typing, and pMLST. Cefotaxime-resistant E. coli were detected in four (1.9 %) samples. Three samples harboured CTX-M-1-producing isolates, and one sample contained two CTX-M-15-producing isolates displaying distinct colony morphology. All isolates belonged to distinct sequence types (STs), including one E. coli lineage previously associated to a human-specific pathotype (ST59). bla(CTX-M-1) was carried on IncI1 plasmids classified as ST3 or ST58 by pMLST, whereas bla(CTX-M-15) was located on IncF/Y and non-typeable plasmids in the two strains isolated from the same sample. CONCLUSIONS: The study shows that dog faeces are a vector for dissemination of CTX-M-producing E. coli within urban areas. The risk derived from human exposure to dog faeces in public gardens depends on the prevalence of these bacteria in the local dog population as well as on the owners’ practice to remove and dispose their dog’s faeces

Prevalence and heritability of distichiasis in the English Cocker spaniel

BACKGROUND: Canine distichiasis is a well-known cause of ocular irritation and excessive lacrimation (secretion of tears) in the dog. The term distichiasis originates from the Greek words di and stichos meaning two and rows, respectively, and as the name implies, the condition is characterized by an additional row of cilia, which erupts on the eyelid margin. Many purebred dogs are known to be predisposed to the condition, with many affected individuals within the populations. Even though the problem is widespread, the exact mode of inheritance and the heredity has not been studied extensively. However, some degree of genetic influence has been assumed, due to the high incidences within specific breeds. In the present study we have examined a cohort of English Cocker spaniels in Denmark to determine the prevalence and heritability of the disease. RESULTS: Data from English Cocker spaniels with an ECVO eye examination registered between 2004–2013 were included in the study. The number of dogs examined during this period was 799, and the prevalence of distichiasis within this cohort was estimated at 49.31 % with a gender predisposition that females are more likely to get distichiasis than males. The correlation between the distichiasis status of the parents and their offspring revealed a significant association between the breeding combination of the parents and the occurrence of distichiasis in the offspring (p <0.0001). A relative risk (RR) ranging from 1.3 to 1.8 demonstrates that offspring of two affected parents are more likely to be affected than offspring descending from either one or two unaffected parents. The heritability was estimated to be moderate to high, i.e., 0.22 to 0.51. CONCLUSIONS: The prevalence of distichiasis in English Cocker spaniels from Denmark, examined in 2004–2013 was shown to be extremely high. The relative risk of developing the disease was 1.3 and 1.8 for offspring of one or two affected parents respectively. This together with the moderate to high heritability of the condition indicates that selective breeding could be used to reduce the incidence of distichiasis

Isolation, Structural Analyses and Biological Activity Assays against Chronic Lymphocytic Leukemia of Two Novel Cytochalasins - Sclerotionigrin A and B

Two new cytochalasins, sclerotionigrin A (1) and B (2) were isolated together with the known proxiphomin (3) from the filamentous fungus Aspergillus sclerotioniger. The structures and relative stereochemistry of 1 and 2 were determined based on comparison with 3, and from extensive 1D and 2D NMR spectroscopic analysis, supported by high resolution mass spectrometry (HRMS). Compounds 2 and 3 displayed cytotoxic activity towards chronic lymphocytic leukemia cells in vitro, with 3 being the most active

Intersectional research stories of responsibilising the family for food, feeding and health in the twenty-first century

Purpose: Literature from across the social sciences and research evidence are used to highlight interdisciplinary and intersectional research approaches to food and family. Responsibilisation emerges as an important thematic thread as family has (compared with the state and corporations) been increasingly made responsible for its members’ health and diet. Approach: Three questions are addressed. First, the extent to which food is fundamentally social, and integral to family identity, as reflected in the sociology of food; Second, how debates about families and food are embedded in global, political and market systems; and thirdly, how food work and caring became constructed as gendered. Findings: Interest in food can be traced back to early explorations of class, political economy, the development of commodity culture, and gender relations. Research across the social sciences and humanities draw on concepts that are implicitly sociological. Food production, mortality and dietary patterns are inextricably linked to the economic/social organization of capitalist societies, including its gender-based divisions of domestic labour. DeVault’s (1991) groundbreaking work reveals the physical and emotional work of providing /feeding families and highlights both its class and gendered dimensions. Family mealtime practices have come to play a key role in the emotional reinforcement of the idea of the nuclear family. Originality/value: Highlights the imperative to take pluri-disciplinary and intersectional approaches to researching food and family. Additionally, this article emphasizes that feeding the family is an inherently political, moral, ethical, social and emotional process, frequently associated with gendered constructions

The Knowing mother:Maternal knowledge and the reinforcement of the feminine consuming subject in magazine advertisements

The caring mother is one of the most recurring images of femininity in post-war advertising. We examine how mothers are depicted as knowing consumers in advertisements in Australian Women’s Weekly and the United Kingdom’s Good Housekeeping magazines between 1950 and 2010. Our data suggest that although visual representations of maternal consumer knowledge change over this period, assumptions about the responsibilities of mothers endure in the family-related advertisements in these women’s magazines. There is a shift over time, however, from a representation of mothers as passive recipients of advice provided by external experts to a more active representation of mothers as experts themselves within both domestic and private spheres. We trace historically how the trope of the knowing mother works as a visual discursive device that helps to reinforce not just patriarchal hegemony, but a particular form of maternal hegemony. The hegemony of motherhood presents a particularly desirable/idealised femininity. However, this visual depiction also serves to gender the very way in which maternal knowledge is to be used. While maternal knowledge is depicted as changing from being merely intuitive or practical to subsuming the technique of knowledge or prescribed expertise; the purposes for which such knowledge is used remain firmly situated within the maternal/feminine realm of nurturing and caring consumption for the family. Despite shifts in discourse that appear to increasingly value mothers’ knowledge—there exists an enduring assumption that mothers should use their knowledge for domestic caring and consumption , ultimately reinforcing a heteronormativity of the use of women’s knowledge that subdues even expert knowledge for a domestic purpose