Limnological Characterization of the Tristate Oxbow Wetland (Ohio, Indiana)

Author Institution: Department of Botany, Miami UniversityWe conducted a limnological study in bodies of water (Oxbow Lake, North Pond, Great Miami River, Ohio River) comprising the Tristate Oxbow Wetland region of southwestern Ohio and southeastern Indiana. This wetland, an extensive and important wildlife habitat located at the confluence of the Great Miami River and the Ohio River, is a region that has been and may in the future be impacted by industrial and commercial development. The present data suggest that Oxbow Lake and North Pond are strongly influenced by seasonal flooding patterns and resultant nutrient loading from the Great Miami River and the Ohio River. On the basis of physico-chemical and biological parameters, Oxbow Lake can be classified as a eutrophic to hypereutrophic system, while North Pond is mesotrophic to eutrophic

Resistencia a la compresión axial del grout f’c=370 kg/cm2 con adición de bentonita, Cajamarca 2022

El Grout es utilizado por su trabajabilidad y alta resistencia, mejorar sus propiedades hidráulicas con bentonita resultaría beneficioso como protección al acero de refuerzo y aumentar la vida útil de la estructura impidiendo las filtraciones de agua y acumulación de humedad. Si bien la adición de bentonita disminuiría su resistencia a compresión del Grout, mejoraría las propiedades de absorción, capilaridad y permeabilidad sin suponer un problema, por las altas capacidades de resistencia a compresión que este posee. Para esto, el objetivo establecido fue determinar la resistencia a la compresión axial del Grout con adición de bentonita en porcentajes de 10%, 20% y 30%. El diseño de esta investigación es experimental; ya que, se usaron materiales y métodos normados y adecuados para el propósito establecido, dichas metodologías fueron los ensayos correspondientes para cuantificar las variables pertinentes. Los resultados obtenidos fueron que la adición de bentonita al SikaGrout 110 disminuye la resistencia a la compresión, aumenta la capilaridad y la absorción y vuelve impermeables a las muestras hasta el 20% de adición de bentonita. Finalmente se concluyó que la mejor proporción de Grout más Lodo bentonitico es 90% Grout y 10% lodo bentonitico; debido a, su mejor desempeño tanto en resistencia a la compresión con un valor de 432.07 kg/cm2 a los 28 días, como en capilaridad con un valor de 72.72 gr.seg/cm2, un porcentaje de absorción medio – bajo y un comportamiento impermeable

The IceCube Realtime Alert System

Following the detection of high-energy astrophysical neutrinos in 2013, their origin is still unknown. Aiming for the identification of an electromagnetic counterpart of a rapidly fading source, we have implemented a realtime analysis framework for the IceCube neutrino observatory. Several analyses selecting neutrinos of astrophysical origin are now operating in realtime at the detector site in Antarctica and are producing alerts to the community to enable rapid follow-up observations. The goal of these observations is to locate the astrophysical objects responsible for these neutrino signals. This paper highlights the infrastructure in place both at the South Pole detector site and at IceCube facilities in the north that have enabled this fast follow-up program to be developed. Additionally, this paper presents the first realtime analyses to be activated within this framework, highlights their sensitivities to astrophysical neutrinos and background event rates, and presents an outlook for future discoveries.Comment: 33 pages, 9 figures, Published in Astroparticle Physic

Investigation on the occurrence and significance of cyclic adenosine 3':5'-monophosphate in phytoplankton and natural aquatic communities

This study is an investigation into the occurrence and potential functions of cyclic adenosine 3':5'-monophosphate (cAMP), a potent and ubiquitous metabolic regulatory molecule in heterotrophic organisms, in phytoplankton and in natural aquatic communities. Laboratory-cultured phytoplankton were grown under both optimal and suboptimal nutrient regimes under constant temperature and illumination regimes. Cellular and extracellular cAMP production, characterized by a number of biochemical techniques, was correlated with growth rate dynamics, chlorophyll a synthesis, /sup 14/C-bicarbonate uptake, alkaline phosphatase activity, and heterocyst formation. The blue-green alga Anabaena flos-aquae was used as a model system in the examination of these metabolic variables. Additionally, this alga was used to test the effects of perturbation of cAMP levels on the aforementioned metabolic variables. Investigations on the occurrence and seasonal dynamics of cAMP in aquatic systems were conducted on Lawrence Lake, a hardwater oligotrophic lake, and on Wintergreen Lake, a hardwater hypereutrophic lake, both in southwestern Michigan. Putative cAMP from both systems was characterized by several biochemical techniques. Weekly sampling of particulate and dissolved cAMP in the epilimnia of both lakes was correlated with data on the rates of primary productivity, alkaline phosphatase activity, chlorophyll a synthesis and changes in phytoplankton community structure

Investigation on the occurrence and significance of cyclic adenosine 3':5'-monophosphate in phytoplankton and natural aquatic communities

This study demonstrates, on the basis of several analyanalytical criteria, that the production and extracellular release of cyclic adenosine 3':5'-monophosphate (cAMP) is widespread among phytoplankton species. The production and release of CAMP varied markedly among different species grown under similar environmental conditions, and intraspecifically during the life cycle of a given algal species. This investigation marks the first time cAMP has been investigated in natural aquatic systems. An examination of epilimnetic lakewater samples from Lawrence Lake, a hardwater oligotrophic lake, and Wintergreen Lake, a hardwater hypereutrophic lake, both in southwestern Michigan, demonstrated that cAMP existed in both particulate-associated and dissolved forms in these systems