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"Pugh, D. T"
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Troubled waters : ocean science and governance
\"Bringing together 30 international experts, this volume commemorates the 50th anniversary of the Intergovernmental Oceanographic Commission of UNESCO, the UN organization responsible for fostering intergovernmental cooperation on global ocean issues. It looks at how governments use science to establish ocean policies, with chapters ranging from the history of ocean management to current advances in marine science, observation and management applications, and the international agencies that co-ordinate this work. With a focus on key topical issues such as marine pollution, exploitation, and hazards, Troubled Waters reflects on past successes and failures in ocean management and emphasises the need for knowledge and effective government action to ensure a sustainable future for this precious resource. Illustrated with dramatic, full-colour images, it is essential reading for researchers, students, policy makers and managers of the marine environment, and also provides an attractive and accessible overview for anyone concerned about the future stewardship of our oceans\"-- Provided by publisher.
Book
Mitochondrial DNA Mutations, Oxidative Stress, and Apoptosis in Mammalian Aging
Mutations in mitochondrial DNA (mtDNA) accumulate in tissues of mammalian species and have been hypothesized to contribute to aging. We show that mice expressing a proofreading-deficient version of the mitochondrial DNA polymerase g (POLG) accumulate mtDNA mutations and display features of accelerated aging. Accumulation of mtDNA mutations was not associated with increased markers of oxidative stress or a defect in cellular proliferation, but was correlated with the induction of apoptotic markers, particularly in tissues characterized by rapid cellular turnover. The levels of apoptotic markers were also found to increase during aging in normal mice. Thus, accumulation of mtDNA mutations that promote apoptosis may be a central mechanism driving mammalian aging.
Journal Article
Long-term and recent changes in sea level in the Falkland Islands
Mean sea level measurements made at Port Louis in the Falkland Islands in 1981–1982, 1984, and 2009, together with values from the nearby permanent tide gauge at Port Stanley, have been compared to measurements made at Port Louis in 1842 by James Clark Ross. The long‐term rate of change of sea level is estimated to have been +0.75 ± 0.35 mm/yr between 1842 and the early 1980s, after correction for air pressure effects and for vertical land movement due to glacial isostatic adjustment (GIA). The 2009 Port Louis data set is of particular importance due to the availability of simultaneous information from Port Stanley. The data set has been employed in two ways, by providing a short recent estimate of mean sea level itself, and by enabling the effective combination of measurements at the two sites. The rate of sea level rise observed since 1992, when the modern Stanley gauge was installed, has been larger at 2.51 ± 0.58 mm/yr, after correction for air pressure and GIA. This rate compares to a value of 2.79 ± 0.42 mm/yr obtained from satellite altimetry in the region over the same period. Such a relatively recent acceleration in the rate of sea level rise is consistent with findings from other locations in the Southern Hemisphere and globally.
Journal Article
Meteorological and internal wave forcing of seiches along the Sri Lanka coast
Regularly observed seiches from tide gauge records around the Sri Lanka coast have been analyzed to determine the forcing mechanisms. The seiche periods range from a few 10s of min to 2 h. Fortnightly and seasonal variations of seiche amplitudes are clearly visible on the east coast. These seiche amplitudes are particularly large approximately 6–8 days after spring tides, with maximum seiche amplitudes observed during March–April and October–November, suggesting that the seiche variation could be related to stratification and internal wave activity. There is no visible fortnightly and seasonal variation of seiche amplitudes in west coast records. Instead, they show a daily pattern with relatively larger seiches around 1000 LT, suggesting that the seiches on the west coast could result from diurnal atmospheric forcing. Barotropic and two‐layer models have been developed to investigate the influence of atmospheric forcing and internal wave activity on the seiches. A barotropic model applied to the west coast shows that the daily seiche amplitude variation could be simulated with cyclic diurnal meteorological forcing. Two‐layer model runs for Trincomalee Bay and the adjacent east coast shelf suggest that seiche amplitudes are proportional to vertical stratification and mixed layer depths. Therefore, the observed seiches there could be excited by internal waves, which originate as far away as the Andaman Sea during spring tides and have a travel time of 6–8 days to the Sri Lankan east coast. However, further studies, including direct measurements of internal wave activity within the region, are required to confirm this hypothesis.
Journal Article
Seiches Around the Shetland Islands
Sea level records have been obtained from a dozen tide gauges deployed around the Shetland Islands, and the high-frequency components of each record have been analysed to determine how the amplitudes and periods of seiches vary from place to place. We have found that seiches occur almost everywhere, although with different periods at different locations, and sometimes with amplitudes exceeding several decimetres. Spectral analysis shows that two or more modes of seiching are present at some sites. The study attempts to explain, with the help of a numerical model, why seiches with particular periods are observed at each location, and what forcings are responsible for them. In particular, we have revisited an earlier study of seiches on the east coast of Shetland by Cartwright and Young (Proc R Soc Lond A 338:111–128, 1974) and find no evidence to support the theory that they proposed for their generation. In addition, we have investigated how often and why the largest seiche events occur at Lerwick (with trough-to-crest wave heights of about 1 m), taking advantage of its long sea level record. Seiches (and other types of high-frequency sea level variability) are often ignored in studies of sea level changes and their coastal impacts. And yet they can be large enough to contribute significantly to the extreme sea levels that have major impacts on the coast. Therefore, our Shetland research serves as a case study of the need to have a fuller understanding of the climatology of seiches for the whole world coastline.
Journal Article
In vivo Cytokine Gene Transfer by Gene Gun Reduces Tumor Growth in Mice
Implantation of tumor cells modified by in vitro cytokine gene transfer has been shown by many investigators to result in potent in vivo antitumor activities in mice. Here we describe an approach to tumor immunotherapy utilizing direct transfection of cytokine genes into tumorbearing animals by particle-mediated gene transfer. In vivo transfection of the human interleukin 6 gene into the tumor site reduced methylcholanthrene-induced fibrosarcoma growth, and a combination of murine tumor necrosis factor α and interferon γ genes inhibited growth of a renal carcinoma tumor model (Renca). In addition, treatment with murine interleukin 2 and interferon γ genes prolonged the survival of Renca tumor-bearing mice and resulted in tumor eradication in 25% of the test animals. Transgene expression was demonstrated in treated tissues by ELISA and immunohistochemical analysis. Significant serum levels of interleukin 6 and interferon γ were detected, demonstrating effective secretion of transgenic proteins from treated skin into the bloodstream. This in vivo cytokine gene therapy approach provides a system for evaluating the antitumor properties of various cytokines in different tumor models and has potential utility for human cancer gene therapy.
Journal Article
Orchiectomy Increases Bone Marrow Interleukin-6 Levels in Mice
Interleukin-6 (IL-6) appears to be an important factor in disease states associated with bone resorption. There is both in vitro and in vivo evidence supporting the fact that androgens down-regulate interleukin-6 production. These observations, in combination with the fact that osteoblasts and bone marrow stromal cells produce IL-6, led us to hypothesize that orchiectomy-induced androgen loss will result in increased IL-6 expression in the bone microenvironment. To prove our hypothesis we assessed the effect of orchiectomy on IL-6 protein and mRNA expression in bone marrow and spleen. We found that orchiectomy was associated with increased serum IL-6 levels at 3 and 28 days postsurgery. Phorbol ester-stimulated IL-6 levels were also higher in supernatants from bone marrow and spleen cell cultures from orchiectomized mice compared with unoperated or sham-operated mice. Additionally, we found that steady state IL-6 mRNA levels were increased in bone marrow but not spleen cells. Finally, we found that orchiectomized mice had splenomegaly and increased bone marrow cellularity. Histopathology of the spleen revealed lymphoid hyperplasia accompanied by a marked mononuclear cell infiltration of the red pulp. We conclude that orchiectomy induces IL-6 expression in the bone marrow. These findings suggest that endocrine and cytokine interactions contribute to bone pathophysiology.
Journal Article
Timed appearance of lymphocytic choriomeningitis virus after gastric inoculation of mice
Arenaviruses present an emerging health threat in agrarian areas of Africa and South America; however, the natural routes of arenaviral infections are not clearly understood. Our previous studies with lymphocytic choriomeningitis virus (LCMV), the prototype arenavirus, implicate oral and intragastric routes as natural routes of infection. Our studies raised many questions about the primary site of infection and the route of dissemination after gastric infection. In this report, we use in situ hybridization to detect LCMV in various organs at different time points (0 to 96 hours). After gastric inoculation, the gastric mucosa is the initial site of viral infection, followed by infection of the spleen and liver, then ileum and last, lung, kidney, brain, and esophagus. Furthermore, our observations suggest that virus is disseminated lymphatically rather than by a hematogenous route. Infectious center assays using mononuclear cells from stomach, blood, and spleen of mice infected by the gastric route confirmed active infection with LCMV and the presence of mononuclear cells producing infectious virus in these tissues. This is the first identification of gastric epithelia as a primary site of virus infection.
Journal Article