Evaluation of Several Commercial Algicides for Control of Odor-producing Cyanobacteria

The production of certain odorous metabolites is an undesirable attribute of cyanobacteria (blue-green algae) growth in aquaculture ponds [e.g., channel catfish(Ictalurus punctatus)] and in drinking water reservoirs. The most common odorous compounds encountered in catfish aquaculture are geosmin (trans-1,10-dimethyltrans-9-decalol) and 2-methylisoborneol(exo-1,2,7,7-tetramethylbicyclo[2.2.1]heptan-2-ol). These compounds are also frequently encountered worldwide in reservoirs and aqueducts used for municipal drinking water systems(Schrader et al. 2002). In this study, several algicides were evaluated using a rapid bioassay to determine their effectiveness in controlling the MIB-producing cyanobacterium Oscillatoria perornata from a west Mississippi catfish pond and the MIBproducing Pseudanabaena sp. (strain LW397) from Lake Whitehurst, Virginia, used as a city water supply reservoir. The cyanobacterium Oscillatoria agardhii , not a MIB-producer, and the green alga Selenastrum capricornutum , found in catfish ponds in the southeastern United States, were included in the bioassay to help determine potential broad-spectrum toxicity of the commercial products. (PDF has 3 pages.

Assisting Nursing Students to Plan for Retirement

The Nursing Leadership and Management faculty felt it was very important to teach career and retirement life lessons . Inadequate retirement savings is an issue that many nurses may face,…preparing for a secure retirement isn\u27t taught in nursing school says Monica Vollmuth, (ANA\u27s Congress of Nursing Practice and Economics). In response, this content was included in a one credit senior seminar course

Contribution of organic farming to conserving and improving biodiversity in Germany avi-fauna as an example

Although it is the aim of organic farming to increase biodiversity, there is little information about the impact of organic farming on birds. From 2001 to 2003, the number of breeding birds was recorded annually on the organic experimental farm of the Institute of Organic Farming (600 ha), and on adjacent conventional and organic farms (60 ha and 40 ha) in Northern Germany. The number of skylark (Alauda arvensis) territories increased considerably after the conversion from conventional to organic farming on the premises of the Institute. Their number remained unvaried on the conventional farm. The highest density of skylark territories was found on the farm which has been under organic management for many years. The number of yellowhammer (Emberiza citronella) territories fluctuated largely in relation to the availability of field margin strips, both on conventional and organic land. During the breeding season aerial hunters (swallows and swifts) and raptors significantly preferred organic fields. Outside the breeding season, densities of raptors (in autumn and in winter), seed-eating birds (in autumn) and insect-eating birds (in autumn) were significantly higher on organic than on conventional fields

A new shielding effectiveness measurement method based on a skin-effect transmission line coupler

We propose a new convenient material shielding effectiveness measurement method based on a skin-effect transmission line coupler. The method is somewhat similar to the arrangement with two coupled TEM cells known from literature. The transmission line coupler consists of a pair of identical transmission line 2-port devices. Each device contains a coaxial waveguide, with a circular inner conductor and an outer conductor having a square cross section. One side of the outer conductor is left completely open as a slot. The slot is surrounded by a large metal housing to contact the two halves. As a measure for the shielding effectiveness the coupling between the two devices is measured in terms of scattering parameters after the test material is brought between the two halves. The devices can be used in a range from low frequencies to a few GHz

Measured Response of Local, Mid-range and Far-range Discontinuities of Large Metal Groundplanes using Time Domain Techniques

This work describes a method to detect and to quantify any local or mid-range discontinuity on extended flat metal planes. Often these planes are used for antenna calibration (open area test site-OATS) or the plane could be the ground of a semi-anechoic chamber used in Electromagnetic Compatibility (EMC) testing. The measurement uncertainty of antenna calibration or EMC testing depends on the groundplane's quality, which can be accessed using this method. A vector network analyzer with time-domain option is used to determine the complex-valued input scattering parameter S̄11,F of an aperture antenna in a monostatic setup. S̄11,F contains the information desired about the discontinuities and is measured in the frequency domain with high dynamic range. But only after a linear filtering utilizing the Chirp-Z-Transform the obtained time-domain signal S̄11,T give clear evidence of local and mid-range discontinuities

Effects of Solids Removal on Water Quality and Channel Catfish Production in a Biofloc Technology Production System

Total suspended solids control was evaluated in a channel catfish (Ictalurus punctatus) biofloc technology production system. Settling chamber flow rates were 0.9 (LO) or 2.9 (HI) L/min to reduce total suspended solids to 300 mg/L; solids were not removed from control tanks. Channel catfish yields (7.6–8.7 kg/m3) were not affected significantly, but control fish were skewed toward smaller size classes. Control treatment channel catfish tolerated 1,410 mg/L total suspended solids without adverse effects. LO- and HI-treatment fillet geosmin concentrations were high enough to be designated as off-flavor. Water quality results suggested that nitrification was affected by solids removal

Positronic lithium, an electronically stable Li-e+^+ ground state

Calculations of the positron-Li system were performed using the Stochastic Variational Method and yielded a minimum energy of -7.53208 Hartree for the L=0 ground state. Unlike previous calculations of this system, the system was found to be stable against dissociation into the Ps + Li$^+$ channel with a binding energy of 0.00217 Hartree and is therefore electronically stable. This is the first instance of a rigorous calculation predicting that it is possible to combine a positron with a neutral atom and form an electronically stable bound state.Comment: 11 pages, 2 tables. To be published in Phys.Rev.Let