A Characterization of Water Chemistry and Plankton from Four Prairie Lakes

Plankton and water chemistry were sampled in four glacial prairie lakes on six dates in 1995 and 1996. Phytoplankton and zooplankton were identified and enumerated. Chemical parameters included nitrate, total kjeldahl nitrogen, total phosphorus, silica, iron, manganese, sodium, potassium, magnesium, calcium, chloride, sulfate, bicarbonate, carbonate and chlorophyll a. Station depth, secchi depth, turbidity, and conductivity were also measured. Two of the lakes were located in moraines and two were located in outwash. One lake was less than 13,000 years old as determined by position, and three were older. Two of the lakes were hypertrophic and two were eutrophic. Two of the lakes were slightly saline in 1995-1996, and two were fresh. Values obtained were compared with previous data bases maintained by the junior author and state agencies from in the 1970\u27s and 1989-1994. Roy Lake (Marshall County) is located in Mankato moraine (less than 13,000 years old). It was slightly saline with the following mean values measured in 1995-6: 1170 uS conductivity, 376 ppm sulfate, 251 ppm bicarbonate, 122 ppm calcium, and 91 ppm magnesium. Roy Lake was eutrophic (7.8 ppb chlorophyll a, 0.03 ppm total phosphorus, 1.31 ppm total nitrogen, 2.32 m secchi depth, and 4.2 ntu turbidity). Mean values for other phytoplankton nutrients were: 0.07 ppm iron, 0.07 ppm manganese, and 8.5 ppm silica. Pickerel Lake (Day County) is older and located in outwash. It was fresh with the following mean values measured in 1995-6: 580 uS Conductivity, 73 ppm sulfate, 189 ppm bicarbonate, 36 ppm calcium, and 34 ppm magnesium. Pickerel Lake was eutrophic (17.7 ppb chlorophyll a, 0.03 ppm total phosphorus, 0.75 ppm total nitrogen, 1.25 m secchi depth, and 7.4 ntu turbidity). Mean values for other phytoplankton nutrients were: 0.17 ppm iron, 0.07 ppm manganese, and 4.5 ppm silica. Bitter Lake (Day County) is older than Pickerel and located in outwash, downstream from Pickerel Lake. Bitter is a saline lake in most years. However, during 1995-6, its water level rose and it was slightly saline with the following mean values measured in 1995-6: 3758 uS conductivity, 3248 ppm sulfate, 386 ppm bicarbonate, 142 ppm chloride, 509 ppm magnesium, 401 ppm sodium, and 93 ppm potassium. Bitter Lake was hypertrophic (33.7 ppb chlorophyll a, 0.64 ppm total phosphorus, 9.56 ppm total nitrogen, 0.78 m secchi depth, and 38.9 ntu turbidity). Mean values for other phytoplankton nutrients were: 0.20 ppm iron, 0.14 ppm manganese, and 5.0 ppm silica. 268 Proceedings of the South Dakota Academy of Science, Vol. 76 (1997) Oak Lake (Brookings County) is located in 14,000 year old moraine. It was fresh with the following mean values measured in 1995-6: 610 uS conductivity, 123 ppm sulfate, 178 ppm bicarbonate, 36 ppm calcium, and 32 ppm magnesium. Oak Lake was hypertrophic (35.6 ppb chlorophyll a, 0.13 ppm total phosphorus, 1.41 ppm total nitrogen, 0.42 m secchi depth, and 37.3 ntu turbidity). Mean values for other phytoplankton nutrients were: 0.28 ppm iron, 0.12 ppm manganese, and 10.3 ppm silica. Comparisons with previous data bases did not indicate major changes between years for Roy, Pickerel and Oak but indicated drastic change between years for Bitter. Major ion concentrations other than calcium were almost an order of magnitude lower in 1995-6 than sampled by the junior author in 1975. In addition, water depth and clarity were much greater in 1995-6 than in all previous years. In previous years Bitter was dominated by non-nitrogen-fixing coccoid bluegreen algae including Anacystis (Microcystis) incerta and cyanea. Anacystis spp. populations were 2 orders of magnitude lower in 1995, however Bitter experienced a heavy bloom of the nitrogen-fixing Aphanizomenon holsaticum (flos-aquae) in midsummer 1995, a species not previously recorded from Bitter

A novel engine mount with semi-active dry friction damping

In this paper the authors present a semi-active engine mount with a controllable friction damper. The normal force of the friction contact is applied by an electromagnetic actuator and can be varied dynamically. The nonlinear current-force-relation of the actuator is linearized. To account for wear and assembly tolerances, an initialization method is developed, that is based on indirect measurement of the actuators inductance. The friction contact is made up of industrial friction pads and a friction rod of steel. The friction model used is suitable especially for small oscillations of the friction damper. The control policy imitates viscous damping forces that exert a minimum of harmonics. Damping is activated only when necessary. Finally the friction mount is compared to the original mount in a row of test rack experiments and also in the car

Differential influence of components resulting from atmospheric-pressure plasma on integrin expression of human HaCaT keratinocytes

Adequate chronic wound healing is a major problem in medicine. A new solution might be non-thermal atmospheric-pressure plasma effectively inactivating microorganisms and influencing cells in wound healing. Plasma components as, for example, radicals can affect cells differently. HaCaT keratinocytes were treated with Dielectric Barrier Discharge plasma (DBD/air, DBD/argon), ozone or hydrogen peroxide to find the components responsible for changes in integrin expression, intracellular ROS formation or apoptosis induction. Dependent on plasma treatment time reduction of recovered cells was observed with no increase of apoptotic cells, but breakdown of mitochondrial membrane potential. DBD/air plasma increased integrins and intracellular ROS. DBD/argon caused minor changes. About 100 ppm ozone did not influence integrins. Hydrogen peroxide caused similar effects compared to DBD/air plasma. In conclusion, effects depended on working gas and exposure time to plasma. Short treatment cycles did neither change integrins nor induce apoptosis or ROS. Longer treatments changed integrins as important for influencing wound healing. Plasma effects on integrins are rather attributed to induction of other ROS than to generation of ozone. Changes of integrins by plasma may provide new solutions of improving wound healing, however, conditions are needed which allow initiating the relevant influence on integrins without being cytotoxic to cells

Monolithic Perovskite Silicon Tandem Solar Cells Fabricated Using Industrial p Type Polycrystalline Silicon on Oxide Passivated Emitter and Rear Cell Silicon Bottom Cell Technology

Combining a perovskite top cell with a conventional passivated emitter and rear cell PERC silicon bottom cell in a monolithically integrated tandem device is an economically attractive solution to boost the power conversion efficiency PCE of silicon single junction technology. Proof of concept perovskite silicon tandem solar cells using high temperature stable bottom cells featuring a polycrystalline silicon on oxide POLO front junction and a PERC type passivated rear side with local aluminum p contacts are reported. For this PERC POLO cell, a process flow that is compatible with industrial, mainstream PERC technology is implemented. Top and bottom cells are connected via a tin doped indium oxide recombination layer. The recombination layer formation on the POLO front junction of the bottom cell is optimized by postdeposition annealing and mitigation of sputter damage. The perovskite top cell is monolithically integrated in a p amp; 8722;i amp; 8722;n junction device architecture. Proof of concept tandem cells demonstrate a PCE of up to 21.3 . Based on the experimental findings and supporting optical simulations, major performance enhancements by process and layer optimization are identified and a PCE potential of 29.5 for these perovskite silicon tandem solar cells with PERC like bottom cell technology is estimate

Ten Years of Pathway Analysis: Current Approaches and Outstanding Challenges

Pathway analysis has become the first choice for gaining insight into the underlying biology of differentially expressed genes and proteins, as it reduces complexity and has increased explanatory power. We discuss the evolution of knowledge base–driven pathway analysis over its first decade, distinctly divided into three generations. We also discuss the limitations that are specific to each generation, and how they are addressed by successive generations of methods. We identify a number of annotation challenges that must be addressed to enable development of the next generation of pathway analysis methods. Furthermore, we identify a number of methodological challenges that the next generation of methods must tackle to take advantage of the technological advances in genomics and proteomics in order to improve specificity, sensitivity, and relevance of pathway analysis

Coastal Upwelling Supplies Oxygen-Depleted Water to the Columbia River Estuary

Low dissolved oxygen (DO) is a common feature of many estuarine and shallow-water environments, and is often attributed to anthropogenic nutrient enrichment from terrestrial-fluvial pathways. However, recent events in the U.S. Pacific Northwest have highlighted that wind-forced upwelling can cause naturally occurring low DO water to move onto the continental shelf, leading to mortalities of benthic fish and invertebrates. Coastal estuaries in the Pacific Northwest are strongly linked to ocean forcings, and here we report observations on the spatial and temporal patterns of oxygen concentration in the Columbia River estuary. Hydrographic measurements were made from transect (spatial survey) or anchor station (temporal survey) deployments over a variety of wind stresses and tidal states during the upwelling seasons of 2006 through 2008. During this period, biologically stressful levels of dissolved oxygen were observed to enter the Columbia River estuary from oceanic sources, with minimum values close to the hypoxic threshold of 2.0 mg L−1. Riverine water was consistently normoxic. Upwelling wind stress controlled the timing and magnitude of low DO events, while tidal-modulated estuarine circulation patterns influenced the spatial extent and duration of exposure to low DO water. Strong upwelling during neap tides produced the largest impact on the estuary. The observed oxygen concentrations likely had deleterious behavioral and physiological consequences for migrating juvenile salmon and benthic crabs. Based on a wind-forced supply mechanism, low DO events are probably common to the Columbia River and other regional estuaries and if conditions on the shelf deteriorate further, as observations and models predict, Pacific Northwest estuarine habitats could experience a decrease in environmental quality

Drons col·laboratius

La robòtica col·laborativa és senzillament robots dissenyats per dur a terme treballs de col·laboració amb els humans. Els robots col·laboratius o cobots són cada cop més utilitzats a les indústries. La robòtica col·laborativa és un dels àmbits d'actualitat en aquests moments. Però també és un dels més interessants en més d'un sentit. Com es comuniquen dos drons autònoms que col·laboren per fer una tasca? Com són aquests missatges que s'envien? Que poden fer que no podrien fer sols? Aquestes són algunes de les preguntes que ens volem respondre en aquest projecte. En aquest treball es presenta un disseny i implementació de dos drons terrestres que es comuniquen per col·laborar entre ells per resoldre una tasca.Collaborative robotics is simply robots designed to perform collaborative work with humans. Collaborative robots or cobots are increasingly used in industries. Collaborative robotics is one of the current topics now. But it is also one of the most interesting in more ways than one. How do two autonomous drones that collaborate to perform a task communicate? How are these messages sent? What can they do that they could not do alone? These are some of the questions we want to answer in this project. This work presents a design and implementation of two ground drones that communicate to collaborate with each other to solve a task.La robótica colaborativa es sencillamente robots diseñados para llevar a cabo trabajos de colaboración con los humanos. Los robots colaborativos o cobots son cada vez más utilizados en las industrias. La robótica colaborativa es uno de los ámbitos de actualidad. Pero también es uno de los más interesantes en más de un sentido. ¿Cómo se comunican drones autónomos que colaboran para hacer una tarea? ¿Cómo son estos mensajes que es envían? ¿Qué pueden hacer que no lo podrían hacer solos? Estas son algunas de las preguntas que queremos responder con este proyecto. En este trabajo se presenta un diseño e implementación de dos drones terrestres que se comunican para colaborar entre ellos para resolver una tarea