Survival and Growth Rate of Channel Catfish as a Function of Dissolved-Oxygen Concentration

Channel catfish were raised in water-recirculating systems for several periods of about six months duration each. Initial stock was fingerling size fish (10 to 20 grams). At dissolved-oxygen levels below 2.5 parts per million, mortality was high. Fish raised in tanks held at dissolved-oxygen levels between 3.0 and 6.8 parts per million showed increased gains of weight for each increment of added oxygen. Weight gains were as much as 50 percent higher at 6.8 parts per million compared with weights at 3.0 parts per million. Feed conversion was good in all cases. When feeding was limited to demand, feed conversion was about the same at all oxygen levels, indicating that reduced oxygen levels resulted in reduced appetites for those fish at lower oxygen levels. Conclusions are that the dissolved-oxygen level should be held as close to saturation as circumstances allow for maximum gain rate

Operation instructions for the cold electron source Final report, part II

Operation and maintenance procedures for cold electron accelerato

Study of Cumulative Growth-Inhibiting Factors in Recycled Water for Catfish Cultivation

Channel catfish were grown in tanks with integral biological filters and complete recirculation of water. After the fish had resided in the tanks for 120 days, solvent extraction was performed on a portion of the tank water. Fresh pond-raised specimen channel catfish showed decreases in their heartbeat rates of about 20 percent when exposed to the extract. This metabolic disturbance is thought to be a factor in reducing the growth rate of fish held in close confinement in recirculating systems

A Study to Improve Dissolved Oxygen Analysis Techniques to Facilitate Water Quality Field Survey Applications

This report describes studies made of the temperature characteristics of dissolved oxygen electrodes having a large surface area. Large area electrodes proved to have much longer lifetime between rejuvenations. Many measurements of dissolved oxygen in water need to be made in field situations where recalibration techniques would be difficult and where making temperature corrections is time consuming for operators who may be making numerous measurements. This study was directed toward design of a compensation circuit for a dissolved oxygen electrode which will give the best possible measurement over a large water temperature range of 5° - 35°C without the necessity of recalibration. Studies were made of the temperature characteristics of dissolved oxygen probes and several electronic circuits with different configurations and components are described. Experimental data using two of the circuits are reported. One method involved using an integrated circuit multiplier module. The best temperature compensation was obtained for a circuit based on a design in which two thermistors were incorporated

Neurogenin1 Defines Zebrafish Cranial Sensory Ganglia Precursors

AbstractCells delaminate from epithelial placodes to form sensory ganglia in the vertebrate head. We describe the formation of cranial neurogenic placodes in the zebrafish, Danio rerio, using bHLH transcription factors as molecular markers. A single neurogenin gene, neurogenin1 (ngn1), is required for the development of all zebrafish cranial ganglia, which contrasts with other described vertebrates. Expression of ngn1 delineates zebrafish ganglionic placodes, including trigeminal, lateral line, and epibranchial placodes. In addition, ngn1 is expressed in a subset of cells within the otic vesicle that will delaminate to form the octaval (statoacoustic) ganglion. The trigeminal placode is the first to differentiate, and forms just lateral and adjacent to the neural crest. Expression of ngn1 is transient and prefigures expression of a related bHLH transcription factor, neuroD. Interfering with ngn1 function using a specific antisense morpholino oligonucleotide blocks differentiation of all cranial ganglia but not associated glial cells. Lateral line sensory neuromasts develop independently of ngn1 function, suggesting that two derivatives of lateral line placodes, ganglia and migrating primordia, are under separate genetic control

Final Report: Buffalo National River Ecosystems

The objective of this study was to sample the Buffalo River on a seasonal basis for a year, in order to determine whether any potential water quality problems existed

An in vivo Biomarker to Characterize Ototoxic Compounds and Novel Protective Therapeutics

There are no approved therapeutics for the prevention of hearing loss and vestibular dysfunction from drugs like aminoglycoside antibiotics. While the mechanisms underlying aminoglycoside ototoxicity remain unresolved, there is considerable evidence that aminoglycosides enter inner ear mechanosensory hair cells through the mechanoelectrical transduction (MET) channel. Inhibition of MET-dependent uptake with small molecules or modified aminoglycosides is a promising otoprotective strategy. To better characterize mammalian ototoxicity and aid in the translation of emerging therapeutics, a biomarker is needed. In the present study we propose that neonatal mice systemically injected with the aminoglycosides G418 conjugated to Texas Red (G418-TR) can be used as a histologic biomarker to characterize in vivo aminoglycoside toxicity. We demonstrate that postnatal day 5 mice, like older mice with functional hearing, show uptake and retention of G418-TR in cochlear hair cells following systemic injection. When we compare G418-TR uptake in other tissues, we find that kidney proximal tubule cells show similar retention. Using ORC-13661, an investigational hearing protection drug, we demonstrate in vivo inhibition of aminoglycoside uptake in mammalian hair cells. This work establishes how systemically administered fluorescently labeled ototoxins in the neonatal mouse can reveal important details about ototoxic drugs and protective therapeutics

Ca2+-permeable AMPARs mediate glutamatergic transmission and excitotoxic damage at the hair cell ribbon synapse

We report functional and structural evidence for GluA2-lacking C

A Survey of the Philosophy and State of the Art of Adaptive Systems

This is a preliminary report on the state of the art of adaptive control. It in no way attempts to review all of the various adaptive systems which have been proposed or constructed® Probably the most complete effort in this direction is WADC TR 59-49# The Proceedings of the Self Adaptive Flight Control Systems Symposium, Edited by P. C. Gregory® Rather this report attempts a synthesis of the present philosophy on adaptive control and is essentially a definition of the problem® The report attempts to subdivide the adaptive control problem into three subdivisions and to assess present progress in each of these areas. Ideas that have been proposed by various authors are brought together and given unified treatment® In making this organization# various gaps in the present state of the art have become apparent and these are under intensive survey presently at Purdue. The initial portion of the project# consisting of this organization terminated several months ago and at present the project personnel are engaged on original research along the lines indicated by the monthly progress reports to WADD. Further interim reports will discuss these items and in accordance with present Air Force practice the final report will contain all of the information of the interim reports and will thus be self sufficient