Depletion of antibiotics from the mammary gland of goats

Four intramammary infusion products were tested in 10 normal goats to determine their rates of depletion from milk. The products tested, which are marketed for treatment of mastitis in the bovine, contained the single active ingredient erythromycin, oxytetracycline, penicillin, or cephapirin. Each mammary gland was infused, after the goats were milked, with the maximum recommended dose of test product (dosing frequency and quantity) for administration to lactating dairy cattle. With one exception, no antibiotics could be detected in the milk by the end of the bovine milk-discard period. Penicillin was detectable in the milk of one goat for 72 h after the last dose of product containing this antibiotic was given (60-h withdrawal period). Only the product containing oxytetracycline produced significant adverse reactions in the mammary gland. The applicator tips of the products were too large for atraumatic insertion into the teat opening of some goats. Overall, results of this limited study indicated that some intramammary infusion products can be used to treat mastitis in the goat if instructions for use in the bovine are followed.     

Two-dimensional encoding by finite-state encoders

Distortion-free compressibility of individual pictures by finite-state encoders is investigated. In a recent paper (see IEEE Trans. Inform. Theory, vol.32, no.1, p.1-8, 1986) the compressibility of a given picture I was defined and shown to be the asymptotically attainable lower bound on the compression ratio that can be achieved for I by any finite-state encoder. Here, a different and more direct approach is taken to prove similar results, which are summarized in a converse-to-coding theorem and a constructive-coding-theorem that leads to a universal asymptotically optimal compression algorithm     

One universally efficient estimation of the first-orderautoregressive parameter and universal data compression

A universal nearly efficient estimator is proposed for the first-order autoregressive (AR) model where the probability distribution of the driving noise is unknown. It is shown that universal estimators for the AR model can be derived from universal data compression algorithms and universal tests for randomness. In other words, estimators derived appropriately from efficient universal codes can be expected to inherit good estimation performance under some conditions. The proposed estimator has a simple information-theoretic interpretation related to universal coding, which can be easily generalized to the higher-order case and to other parametric models, e.g. the one-sample location model, the two-sample location model, and the linear regression model     

Variable-to-fixed length codes are better than fixed-to-variablelength codes for Markov sources

It is demonstrated that for finite-alphabet, kth-order ergodic Markov sources (i.e. memory of k letters), a variable-to-fixed length code is better than the best fixed-to-variable length code (Huffman code). It is shown how to construct a variable-to-fixed length code for a kth order ergodic Markov source, which compresses more effectively than the best fixed-to-variable code     

On Finite Memory Universal Data Compression and Classification of Individual Sequences

Consider the case where consecutive blocks of letters of a semi-infinite individual sequence over a finite-alphabet are being compressed into binary sequences by some one-to-one mapping. No a priori information about is available at the encoder, which must therefore adopt a universal data-compression algorithm. It is known that if the universal Lempel-Ziv (LZ) data compression algorithm is successively applied to -blocks then the best error-free compression, for the particular individual sequence is achieved as tends to infinity. The best possible compression that may be achieved by any universal data compression algorithm for finite -blocks is discussed. It is demonstrated that context tree coding essentially achieves it. Next, consider a device called classifier (or discriminator) that observes an individual training sequence . The classifier's task is to examine individual test sequences of length and decide whether the test -sequence has the same features as those that are captured by the training sequence , or is sufficiently different, according to some appropriate criterion. Here again, it is demonstrated that a particular universal context classifier with a storage-space complexity that is linear in , is essentially optimal. This may contribute a theoretical ldquoindividual sequencerdquo justification for the Probabilistic Suffix Tree (PST) approach in learning theory and in computational biology.     

Upper bounds on the probability of sequences emitted byfinite-state sources and on the redundancy of the Lempel-Ziv algorithm

An upper bound on the probability of a sequence drawn from a finite-state source is derived. The bound is given in terms of the number of phrases obtained by parsing the sequence according to the Lempel-Ziv (L-Z) incremental parsing rule, and is universal in the sense that it does not depend on the statistical parameters that characterize the source. This bound is used to derive an upper bound on the redundance of the L-Z universal data compression algorithm applied to finite-state sources, that depends on the length N of the sequence, on the number K of states of the source, and, eventually, on the source entropy. A variation of the L-Z algorithm is presented, and an upper bound on its redundancy is derived for finite-state sources. A method to derive tighter implicit upper bounds on the redundancy of both algorithms is also given, and it is shown that for the proposed variation this bound is smaller than for the original L-Z algorithm, or every value of N and K     

On sliding-window universal data compression with limited memory

Nonasymptotic coding and converse theorems are derived for universal data compression algorithms in cases where the training sequence (“history”) that is available to the encoder consists of the most recent segment of the input data string that has been processed, but is not large enough so as to yield the ultimate compression, namely, the entropy of the source     

Lessons learned from six years of international administrations of the ECFMG''s SP-based clinical skills assessment

Thapsigargin (TG), a plant-derived sesquiterpene lactone, inhibits several isoforms of both the sarcoplasmic and endoplasmic reticulum Ca2+-ATPases. Thus, intracellular Ca2+ stores found in the endoplasmic reticulum can be released by this compound. The mammalian sperm acrosome reaction (AR) depends on influx of extracellular Ca2+. However, few reports have presented evidence for the involvement of putative Ca2+ stores and intracellular Ca2+ mobilization in the AR. Thus, we designed experiments to evaluate the effect of TG on the hamster sperm AR. Thapsigargin stimulated-in a dose-dependent manner-the AR of spermatozoa previously capacitated for at least 3 hr, not affecting sperm motility. A maximal stimulatory effect was apparent 3 min after addition of TG to spermatozoa previously capacitated for 4 hr and was dependent on external Ca2+ since ethyleneglycol-bis-(b-amino-ethyl ether) N,N'-tetra-acetic acid added 1 min before TG completely inhibited AR stimulation. The Ca2+ channel blockers diltiazem and nifedipine also abolished the TG-stimulatory effect when added to capacitated spermatozoa 10 min before the inhibitor. In addition, the trypsin inhibitors p-nitrophenyl-p'-guanidine-benzoate hydrochloride and benzamidine added to the sperm suspensions 10 min before TG inhibited by 70-80% the TG-induced AR. These results indicate that putative Ca2+ stores release may be involved in stimulation of extracellular Ca2+ influx required for the occurrence of the AR. In addition, a sperm trypsin-like protease may be part of the mechanism by which TG induces the hamster sperm AR.     

Measurements and numerical simulations for optimization of the combustion process in a utility boiler

A three‐dimensional computational fluid dynamics code was used to analyse the performance of 550MW pulverized coal combustion opposite a wall‐fired boiler (of IEC) at different operation modes. The main objective of this study was to prove that connecting plant measurements with three‐dimensional furnace modelling is a cost‐effective method for design, optimization and problem solving in power plant operation. Heat flux results from calculations were compared with measurements in the boiler and showed good agreement. Consequently, the code was used to study hydrodynamic aspects of air–flue gases mixing in the upper part of the boiler. It was demonstrated that effective mixing between flue gases and overfire air is of essential importance for CO reburning. From our complementary experimental‐numerical effort, IEC considers a possibility to improve the boiler performance by replacing the existing OFA nozzles by those with higher penetration depth of the air jets, with the aim to ensure proper mixing to achieve better CO reburning. Copyright © 2004 John Wiley & Sons, Ltd.