Proceedings: Female sterilization: long-term follow-up with particular reference to regret

220 women who had been sterilized 20-46 months previously were questioned about any regrets they felt about the operation. 13 patients expressed regret (5.9%) and 15 expressed uncertainty (6.8%). The worsening of the sex life, the occurrence of menorrhagia, dysmenorrhea, or both, and nervous problems were each significantly associated with the regret/uncertain group (p less than .01). 7 patients also experienced weight gain and 3 reported a bad conscience. The percentage of sterilization patients expressing regret is felt likely to decline since smaller families are now favored. The results did not indicate that sterilization necessarily causes the problem.     

The natural cross-pollination of crop plants with particular reference to the radish

Experiments were carried out to determine what degree of intervarietal cross-pollination occurs when two radish varieties are grown at varying distances apart. The varieties chosen were Icicle and Scarlet Globe. Hybrids are distinctive; thus crossing is readily determined.
In closely planted experiments, where one half of the plot was Icicle and the other half Scarlet Globe, the amount of intercrossing ranged from 30 to 40 % at a distance of 9 in. to an average of about 1 % at 15 ft. Intercrossing decreased fairly regularly and rapidly with distance.
Single plants of Icicle were run out from plots of Scarlet Globe; in 1941 at distances from 9 in. to 95 ft. and in 1942 from 9 in. to 408 ft. In the plants near the red plots crossing was approximately 100 %. In 1941 there was a regular and rapid fall with distance and intervarietal crossing stopped at 95 ft. In 1942 the plots were closer to beehives; intercrossing was less regular and extended farther than in 1941, but beyond 240 ft. it was only 0.1%, and in an all-white plot 360 ft. from a red plot with no intervening stringer plants it was nil.
Given a mass of plants and a profusion of flowers, bees confine their flower visiting to a small area. When radishes are grown in quantity 300 ft. guards against contamination of stock due to intervarietal crossing. If only small numbers are grown intercrossing is likely to occur over a greater distance.     

An ecological study of a small New Zealand stream with particular reference to the Oligochaeta

The composition, temporal and spatial distribution, and productivity of profundal benthos were investigated in a Colorado Front Range reservoir which impounds water diverted from the Western Slope of the Rocky Mountains. Horsetooth Reservoir, 10.6 km × 1.0 km, consists of three basins with depths greater than 50 m connected by two equalizing channels ca. 30 m deep. Water quality parameters did not vary significantly between sites, but temperature, pH, and dissolved oxygen varied seasonally. The composition and organic content of sediment exhibited a gradient from inlet to outlet which significantly influenced faunal density and distribution patterns. Although 28 genera of macroinvertebrates were collected, the oligochaetes Tubifex tubifex (Müller) and Limnodrilus hoffmeisteri Claparède comprised 97.6% of the total organisms. Chironomids comprised 2.2%. The relative contribution of chironomids to total biomass decreased with increasing depth; the reverse was true for oligochaetes. Mean annual density ranged from 3,827 to 51,901 total organisms/m² for six sampling sites. Mean annual biomass varied from 0.16 to 2.3 g ash-free dry wt/m². Annual turnover ratios ranged from 3.6 to 4.5. Annual production estimates varied from 7.2 to 82.8 kg/ha ash-free dry weight, averaging 39.3 kg/ha or 26.9 kcal/m².     

Inheritance of components of partial resistance of barley to Rhynchosporium secalis with particular reference to race specificity

Six spring barley cultivars with no known genes for resistance to specific virulences but varying in partial resistance to Rhynchosporium secalis, were crossed in all combinations (6 × 6 diallel including reciprocals). In addition to seeds from naturally selfed plants, seeds of all parent cultivars were also produced by artificial selfing (emasculation followed by pollination using pollen from the same cultivar). This ensured comparability between seeds of parents and F₁. Both sets of parents, F₁ and F₂ families were grown in the field as single spaced plants and inoculated at Zadoks growth stage 49 with spore suspensions (2 × 10⁶ spores ml^-1) of three races (pathotypes) of R. secalis (Zadoks, Chang & Konzak, 1974). Components of partial resistance, incubation period (ICP), infection frequency (IF) and spore production per lesion (SP/L) were assessed on each plant. There were highly significant differences for all three components of partial resistance in both sets of parent cultivars but rank order in both sets was similar as evidenced by correlation coefficients, r= 0.96 for ICP and IF and r= 0.87 for SP/L. All three components of partial resistance were strongly correlated with NIAB (National Institute of Agricultural Botany, Cambridge, UK) resistance ratings. Means of F₁ and F₂ families were correlated with mid-parent values for ICP and IF but not SP/L. No difference in aggressiveness was found between races but for each component of partial resistance there was a significant interaction between race and parent cultivar (artificial selfs) and, for IF and ICP, a significant interaction between race and F₁ family. There was no evidence of interaction between parent (natural selfs) and race nor between race and F₂ family. Examination of genetic control of resistance showed evidence of strong additive effects (combining ability) in both F₁ and F₂ for ICP and IF but not for SP/L. There was no evidence for maternal or reciprocal differences, but there was evidence for dominance effects although their nature differed between components of partial resistance and between F₁ and F₂ generations. In the F₁, but not the F₂ generation, several elements of dominance (direction, distribution of dominant genes between parent cultivars, specific combining ability) showed for ICP or IF (but not SP/L) significant interaction with race.     

An experimental model of chemotherapy on dormant tuberculous infection, with particular reference to rifampicin

Mice were infected intravenously with a streptomycin (SM)-dependent strain of tubercle bacilli which had been starved of the antibiotic. The inoculum persisted in the spleen for a fairly long period, especially keeping almost the initial level of viable counts in the first few weeks. Isoniazid (INH) administration exerted little effect on such fate of the infection at a bactericidal dose to the same strain multiplying under the supply of SM. Rifampicin (RFP) was, however, highly effective in either case. Similar results were obtained in the corresponding in vitro experiments. The data suggest that this animal model is a convenient system for screening drugs effective on the dormant tuberculous infection.     

Inorganic speciation of organotin(IV) cations in natural waters with particular reference to seawater

Abstract

This paper examines the inorganic complexing capacity of seawater, where chloride and sulfate ions are present in high concentration, towards mono- di- and tri-organotin(IV) cations which show a different trend of acidity, depending on cation charges, and a corresponding tendency to hydrolysis. By considering hydrolytic species and chloride and sulphate complex formation, a basic inorganic speciation model of organotins in synthetic seawater (Na⁺, K⁺, Ca²⁺, Mg²⁺, Cl^?, SO₄^2?) has been built up. The model has been extended to also consider interactions of organotins with carbonate and fluoride ions, which are other important components of seawater. Because of the strength of hydrolysis processes, the main complexes formed are in general mixed hydroxo-species. No species are formed by organotin cations and/or their hydroxo-species with fluoride owing to their very low concentration in fluoride, in comparison to the other components of seawater. In order to simplify calculations and to establish a cumulative inorganic binding capacity for seawater, we applied a chemical complexation model, according to which the major inorganic components of seawater are considered as a single salt BA.     

A survey of soil microorganisms,with particular reference to the actinomycetes as sources of substances toxic to Heliothis virescens

Cultures of microorganisms isolated from cultivated soils were grown in submerged fermentation in test tubes kept on a rotary shaker at 28°C for 5 days using a fermentation medium composed primarily of soybean flour and dextrose. The beers were harvested and centrifuged, and the supernatants were incorporated at a dilution of 1:10 into artificial diets on which neonate larvae of Heliothis virescens were allowed to feed ad libitum for 7 days. If the beer killed or markedly retarded the development of at least 50% of the test larvae, the culture was regrown in shaken cultures in 500-ml Erlenmeyer flasks and assayed again. If a culture produced toxic beers in both fermentations, it was considered active. Over 2100 soil isolates were tested, of which an estimated 95% were actinomycetes. Slightly over 0.4% of the isolates were active, all of which, probably due to our selection procedure, were actinomycetes.     

Studies on the Golgi apparatus by electron microscopy with particular reference to Aoyama's technique

1. Aoyama's silver impregnation method for the Golgi apparatus has been used on exocrine cells of the pancreas of the mouse and studied by electron microscopy in order to determine as precisely as possible where the silver is deposited. Similar cells have also been fixed in buffered osmium tetroxide solution and compared with cells treated by the silver technique. 2. Examination of the Aoyama preparations usually revealed a light deposition of silver in the cytoplasm (hyaloplasm or matrix) and a heavy deposition of silver around a series of closely apposed vacuoles. The heavy deposition of silver was regarded as revealing the chromophilic region of the Golgi apparatus while the vacuoles were identified as the chromophobic component. 3. Comparison of the silver preparations with those fixed in buffered osmium tetroxide solution showed that the silver was primarily deposited in the region of the Golgi membranes.