A COMPARATIVE STUDY OF FOLPMERS' GLUTAMIC ACID MEDIUM FOR THE DETECTION OF BACT. COLI IN WATER

SUMMARY: Folpmers' glutamic acid medium and certain modifications of it have been compared with MacConkey's broth for the detection of organisms of the coli-aerogenes group in water. Very satisfactory results were obtained with the glutamic acid medium made up in tubes and incubated in the same way as with MacConkey's broth. Less satisfactory acid were obtained when lactose was substituted for glucose in the glutamic acid medium, although both were superior to MacConkey's broth. The anaerobic method as described by Folpmers had too many disadvantages to be practicable for the routine examination of large numbers of samples.     

A general Akaike-type criterion for model selection in robust regression

Akaike's procedure (1970) for selecting a model minimises anestimate of the expected squared error in predicting new, independentobservations. This selection criterion was designed for modelsfitted by least squares. A different model-fitting technique,such as least absolute deviation regression, requires an appropriatemodel selection procedure. This paper presents a general Akaike-typecriterion applicable to a wide variety of loss functions formodel fitting. It requires only that the function be convexwith a unique minimum, and twice differentiable in expectation.Simulations show that the estimators proposed here well approximatetheir respective prediction errors.     

ULTRASONIC VOCALIZATIONS AND THEIR ASSOCIATIONS WITH THE NON-VOCALIZATION BEHAVIOUR OF THE ENDANGERED TURKISH SPINY MOUSE ACOMYS CILICIUS SPITZENBERGER IN A CAPTIVE POPULATION

ABSTRACT

Although ultrasonic vocalizations (USVs) have been recorded in many species of rodent and in various contexts, e.g. sexual behaviour and aggression, it has not been demonstrated for the endangered Turkish Spiny Mouse Acomys cilicius Spitzenberger. This study investigated whether A. cilicius emits USVs and, if so, how these USVs associated with non-vocalization behaviour. Ultrasonic recording equipment was set up for 12 days in an off-exhibit enclosure of A. cilicius at Bristol Zoo. At least seven different types of USV were recorded. For eight of the 12 study days, ultrasonic and video recording equipment were run concurrently. From these observations it was found that emission of USVs were associated with sexual behaviour, aggression and social investigation. The results of this study show for the first time that captive A. cilicius produce USVs that resemble those produced by other rodent species, including its close relative the Egyptian Spiny Mouse A. cahirinus Desmarest. As these findings apply only to a captive Turkish Spiny Mouse population, additional work should be carried out to investigate the behaviour and USV production in the wild in addition to further research on captive populations investigating the apparent communicative function of these vocalizations.     

Cl- Fluxes during Osmoregulation in Chara

Measurements of Cl^– influx in cells of Chara corallinashow that control of this flux contributes to the ability ofthis cell to regulate its osmotic pressure. Transcellular osmosiswas used to generate cell fragments with abnormally high ₁,(H-cells), and with abnormally low ₁, (L-cells). Plasmalemmainflux (_oc) was very high in L-cells, and markedly reduced inH-cells. Influx was not affected by the presence of sucrosein the pond water and the consequent reduction in turgor. InH-cells the chloride flux from cytoplasm to vacuole (_cv) wasalso strongly inhibited. It is suggested that control of Cl^–fluxes at both plasmalemma and tonoplast is involved in osmoregulationin these cells. Key words: Chara corallina, osmoregulation, Cl^– flux     

Techniques for the Assessment of Growth of Micro-organisms on Plumbing Materials Used in Contact with Potable Water Supplies

Water samples from plumbing installations have often been of poorer microbiological quality than samples collected from the distribution main. This deterioration is often associated with a musty taste or visible turbidity in the water and slimes have sometimes been observed on water fittings. A technique to assess the ability of plumbing materials to support microbial growth is described and the most common categories of materials capable of supporting growth are identified. The most significant micro-organisms frequently found to grow on unsuitable materials were coliform organisms, especially members of the genus Citrobacter. Aeromonas hydrophila, Pseudomonas aeruginosa and fungi.