1,123 research outputs found

    1862-06-14 A.C. Spaulding submits bills to Governor Washburn

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    https://digitalmaine.com/cw_me_1st_cav/1298/thumbnail.jp

    1862-06-01 A.C. Spaulding reports to General Hodsdon about casualties

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    https://digitalmaine.com/cw_me_1st_cav/1284/thumbnail.jp

    1862-06-04 A.C. Spaulding writes Governor Washburn about the killed and wounded of the regiment

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    https://digitalmaine.com/cw_me_1st_cav/1285/thumbnail.jp

    1862-06-09 A.C. Spaulding sends his bill for services

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    https://digitalmaine.com/cw_me_1st_cav/1287/thumbnail.jp

    Repeat late instent-stenosis after an interval of four years in the same lesion after bare-metal and drug-eluting stent: a case report

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    In 2001, a 71-year old male was admitted to our hospital with unstable angina. The angiography revealed 2-vessel disease with a 90% stenosis of the proximal LAD. A bare-metal stent was implanted. Four years later the angiography showed a 80% instent-stenosis in the bare-metal stent but no progress at the other coronary arteries. A DES was implanted. Again, four years later, the patient presented with non-ST-elevation myocardial infarction. Angiography showed a 90% instent-restenosis, again without any progession of coronary artery disease in the other vessels. Again a DES implanted. Therefore the processes involved in the late instent-stenosis were not influenced by the antiproliferative agent sirolimu

    Separating the Influences of Diagenesis, Productivity and Anthropogenic Nitrogen Deposition on Sedimentary δ15N Variations

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    The stable isotopic composition of nitrogen (δ15N) in organic lake sediments is frequently used to infer changes in the source or cycling of N prior to sedimentation. However, diagenetic processes that occur after sedimentation can systematically alter the primary isotopic signal recorded in sedimentary organic matter and must be accounted for in order to detect changes in the δ15N of nitrogen inputs to the sediment surface. Here we present a null model that estimates the diagenetic effect on sedimentary lake δ15N records. The model was tested using lake sediment cores from relatively pristine alpine lakes in the Wind River and Teton Ranges of Wyoming, USA. Model-inferred increases in productivity were tested against independent productivity proxies (diatom accumulation rates and the planktonic to benthic ratio), and inferred changes in anthropogenic nitrogen contribution were validated with records of atmospheric nitrogen deposition from the nearby Fremont Glacier, Wyoming. Diagenetic overprinting significantly altered sediment δ15N profiles, and the degree of alteration was not constant through time. Of the cores analyzed, ∼30–70% of the variability can be explained by diagenesis alone, with the remainder explained by either a change in productivity or a change in the isotopic composition of the source material. Our null model of isotopic fractionation proved to be successful at separating the diagenetic overprinting from other causes of isotopic shifts, thereby providing environmental scientists with an analytical tool to partition the effects of diagenesis and environmental change on sedimentary δ15N values

    Didymosphenia geminata: Algal blooms in oligotrophic streams and rivers

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    In recent decades, the diatom Didymosphenia geminata has emerged as nuisance species in river systems around the world. This periphytic alga forms large “blooms” in temperate streams, presenting a counterintuitive result: the blooms occur primarily in oligotrophic streams and rivers, where phosphorus (P) availability typically limits primary production. The goal of this study is to examine how high algal biomass is formed under low P conditions. We reveal a biogeochemical process by which D. geminata mats concentrate P from flowing waters. First, the mucopolysaccaride stalks of D. geminata adsorb both iron (Fe) and P. Second, enzymatic and bacterial processes interact with Fe to increase the biological availability of P. We propose that a positive feedback between total stalk biomass and high growth rate is created, which results in abundant P for cell division. The affinity of stalks for Fe in association with iron-phosphorus biogeochemistry suggest a resolution to the paradox of algal blooms in oliogotrophic streams and rivers

    Dust Mediated Transfer of Phosphorus to Alpine Lake Ecosystems of the Wind River Range, Wyoming, USA

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    Alpine lakes receive a large fraction of their nutrients from atmospheric sources and are consequently sensitive to variations in both the amount and chemistry of atmospheric deposition. In this study we explored the spatial changes in lake water chemistry and biology along a gradient of dust deposition in the Wind River Range, Wyoming. Regional differences were explored using the variation in bulk deposition, lake water, sediment, and bedrock geochemistry and catchment characteristics. Dust deposition rates in the Southwestern region averaged 3.34 g m−2 year−1, approximately three times higher than deposition rates in the Northwestern region (average 1.06 g m−2 year−1). Dust-P deposition rates ranged from 87 µg P m2 day−1 in the Northwestern region to 276 µg P m2 day−1 in the Southwestern region. Subalpine and alpine lakes in the Southwestern region had greater total phosphorus (TP) concentrations (5–13 µg L−1) and greater sediment phosphorus (SP) concentrations (2–5 mg g−1) than similar lakes elsewhere in the region (1–8 µg L−1 TP, 0.5–2 mg g−1 SP). Lake phosphorus concentrations were related to dissolved organic carbon (DOC) across vegetation gradients, but related to the percent of bare rock, catchment area to lake area, and catchment steepness across dust deposition gradients. Modern phytoplankton and zooplankton biomasses were two orders of magnitude greater in the Southwest than in the Northwest, and alpine lakes in the Southwest had a unique diatom species assemblage with relatively higher concentrations of Asterionella formosa, Pseudostaurosira pseudoconstruens, and Pseudostaurosira brevistriata. These results suggests that catchment controls on P export to lakes (i.e. DOC) are overridden in dominantly bare rock basins where poor soils cannot effectively retain dust deposited P

    Hydroacoustic Assessment of Abundance and Diel Distribution of Sockeye Salmon and Kokanee in the Sawtooth Valley Lakes, Idaho

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    We used dual-beam hydroacoustics and echo integration techniques, combined with midwater trawling and gillnetting, to assess the abundance and distribution of the endangered Snake River juvenile sockeye salmon and resident kokanee (both Oncorhynchus nerka) in Sawtooth Valley lakes of Idaho during September 1991 and 1992. Abundance of O. nerka varied among the four lakes containing this species (12,500–257,000) and varied between years in Redfish Lake (86,400 in 1994 and 241,000 in 1992) and Alturas Lake (230,000 in 1991 and 257,000 in 1992). In Alturas Lake, where piscivore densities were high and zooplankton densities were low, small acoustic targets (≤18 cm long) were nearly absent from the limnetic zone during daylight, and high densities remained in colder intermediate depths (15–30 m) during crepuscular and nocturnal periods. In Redfish Lake, where predator density was much lower and zooplankton density was higher, targets concentrated in schools at 25–30 m during daylight, dispersed into the upper 10 m at dusk, then were broadly distributed over the upper 30 m at night. In Pettit and Stanley lakes, nocturnal distributions of smaller (3–7 cm) and intermediate (7–18 cm) target sizes were skewed toward the epilimnion, and larger targets remained in the metalimnion or upper hypolimnion. The different diel vertical distribution patterns suggested that juvenile O. nerka exposed to limited food and high predation risk consumed smaller rations and maximized bioenergetic efficiency. Populations with higher food supplies and exposed to lower piscivore densities exploited the higher epilimnetic prey densities and temperatures at night and crepuscular periods to maximize growth but deviated further from bioenergetic efficiency. Populations responded differently to the unique combination of constraints that limit potential sockeye salmon smolt production at each lake. Consequently, different management strategies may be needed in each lake
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