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

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

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

Operation and maintenance procedures for cold electron accelerato

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

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

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

A 2k2k-Vertex Kernel for Maximum Internal Spanning Tree

We consider the parameterized version of the maximum internal spanning tree problem, which, given an $n$-vertex graph and a parameter $k$, asks for a spanning tree with at least $k$ internal vertices. Fomin et al. [J. Comput. System Sci., 79:1-6] crafted a very ingenious reduction rule, and showed that a simple application of this rule is sufficient to yield a $3k$-vertex kernel. Here we propose a novel way to use the same reduction rule, resulting in an improved $2k$-vertex kernel. Our algorithm applies first a greedy procedure consisting of a sequence of local exchange operations, which ends with a local-optimal spanning tree, and then uses this special tree to find a reducible structure. As a corollary of our kernel, we obtain a deterministic algorithm for the problem running in time $4^k \cdot n^{O(1)}$

Mixtures in non stable Levy processes

We analyze the Levy processes produced by means of two interconnected classes of non stable, infinitely divisible distribution: the Variance Gamma and the Student laws. While the Variance Gamma family is closed under convolution, the Student one is not: this makes its time evolution more complicated. We prove that -- at least for one particular type of Student processes suggested by recent empirical results, and for integral times -- the distribution of the process is a mixture of other types of Student distributions, randomized by means of a new probability distribution. The mixture is such that along the time the asymptotic behavior of the probability density functions always coincide with that of the generating Student law. We put forward the conjecture that this can be a general feature of the Student processes. We finally analyze the Ornstein--Uhlenbeck process driven by our Levy noises and show a few simulation of it.Comment: 28 pages, 3 figures, to be published in J. Phys. A: Math. Ge

ORC-13661 protects sensory hair cells from aminoglycoside and cisplatin ototoxicity

Aminoglycoside (AG) antibiotics are widely used to prevent life-threatening infections, and cisplatin is used in the treatment of various cancers, but both are ototoxic and result in loss of sensory hair cells from the inner ear. ORC-13661 is a new drug that was derived from PROTO-1, a compound first identified as protective in a large-scale screen utilizing hair cells in the lateral line organs of zebrafish larvae. Here, we demonstrate, in zebrafish larvae and in mouse cochlear cultures, that ORC-13661 provides robust protection of hair cells against both ototoxins, the AGs and cisplatin. ORC-13661 also prevents both hearing loss in a dose-dependent manner in rats treated with amikacin and the loading of neomycin-Texas Red into lateral line hair cells. In addition, patch-clamp recordings in mouse cochlear cultures reveal that ORC-13661 is a high-affinity permeant blocker of the mechanoelectrical transducer (MET) channel in outer hair cells, suggesting that it may reduce the toxicity of AGs by directly competing for entry at the level of the MET channel and of cisplatin by a MET-dependent mechanism. ORC-13661 is therefore a promising and versatile protectant that reversibly blocks the hair cell MET channel and operates across multiple species and toxins

Causes and Consequences of Past and Projected Scandinavian Summer Temperatures, 500–2100 AD

Tree rings dominate millennium-long temperature reconstructions and many records originate from Scandinavia, an area for which the relative roles of external forcing and internal variation on climatic changes are, however, not yet fully understood. Here we compile 1,179 series of maximum latewood density measurements from 25 conifer sites in northern Scandinavia, establish a suite of 36 subset chronologies, and analyse their climate signal. A new reconstruction for the 1483–2006 period correlates at 0.80 with June–August temperatures back to 1860. Summer cooling during the early 17th century and peak warming in the 1930s translate into a decadal amplitude of 2.9°C, which agrees with existing Scandinavian tree-ring proxies. Climate model simulations reveal similar amounts of mid to low frequency variability, suggesting that internal ocean-atmosphere feedbacks likely influenced Scandinavian temperatures more than external forcing. Projected 21st century warming under the SRES A2 scenario would, however, exceed the reconstructed temperature envelope of the past 1,500 years