ALBERT

Notes: Zusammenfassung Die somatischen Chromosomen von 100 Ratten (Wildfänge),Neotoma micropus Baird (Cricetidae), zeigen ein nicht-Robertsonsches polymorphes System mit 2 verschiedenen homologen Chromosomenpaaren. Sie stellen 4 verschiedene Rattenpopulationen mit Polymorphismus dar.

Notes: Abstract Collection and culture of the large lobate ctenophore Mnemiopsis mccradyi Mayer is described, including the requirements for successful development of larvae. Particular attention must be given to the collection of these delicate animals, the handling and provision of live microzooplankton of suitable size for the larvae, and the provision of food densities for the adults which neither stimulate “wasteful” feeding nor limit their growth. Although these ctenophores will ingest detritus and algal cells in high concentration, they lost weight at the same rate as starved individuals unless provided with living zooplankton. Under optimum conditions, specimens would lay eggs within 13 days of their own birth. By the 17th day they laid eggs daily, and had produced an average of 8,000 eggs within 23 days after birth. The maximum number of eggs laid by a single wild individual within 24 h after being brought into the laboratory was 10,000. Their high fecundity, rapid generation time, and ability to self-fertilize help to explain their sudden appearance in bloom proportions at periods of high food concentration in the environment, often referred to in the literature.

Notes: Summary We have determined unidirectional influxes by measuring rate of uptake between 0.5 and 1.0 min of incubation in 5mm galactose.3H-inulin was used to correct for galactose in residual mucosal solution. Influx was greatly depressed by removing Na+ from or adding 10−4 m phlorizin to the incubation medium. Influx was also greatly depressed by making the mucosal solution anaerobic during a 10-min preincubation period. The same severe inhibition of galactose influx by mucosal anaerobiosis also occurrend under conditions in which the epithelial cells did not gain Na+. After taking into account the effect of the mucosal unstirred water layer, influxes could be normalized to a concentration of 1.0mm at the membrane surface. It was estimated that at 1.0mm the phlorizin-sensitive component of galactose influx was reduced 93% by 10 min of mucosal anaerobiosis. Unidirectional effluxes were estimated by subtracting steady-state downhill mucosal-to-serosal flux from influx. The ease of efflux was apparently augmented 2.8-fold by mucosal anaerobiosis. After 10 min of mucosal anaerobiosis, there was no longer any directional preference for movement of galactose across the brush border and there was no uphill transport, in spite of the persistence of a large Na+ gradient. These results provide strong evidence against the theory that ion gradients provide the major source of energy for directional preference and uphill transport.

Notes: Summary The osmotic pressure (OP) of the incubation medium directly affects synthesis and release of prolactin byPoecilia andAnguilla pituitariesin vitro. There is an inverse relationship between the OP of the medium and the amount of prolactin released into the medium (Pigs. 1, 2; Tables 1, 3). Release of newly-synthesised prolactin is similarly related to OP of the medium (Pigs. 3,4; Table 3). Histometric data of prolactin cells also suggests that hormone synthesis is reduced in high OP media (Table 2). Release and synthesis of putative growth hormone (GH) byPoecilia pituitaries is not influenced by OP of the medium (Table 4), butAnguilla pituitaries release more GH in low OP media (Table 5).

Notes: Summary Hearts of 17-day-old chick embryos were assayed for alterations in lactic dehydrogenase and cytochrome oxidase activity following exposure to 425 ppm carbon monoxide during the previous 24 to 168 hours of incubation. The level of the heme-containing enzyme, cytochrome oxidase, was significantly less in the exposed than in the control embryos, and biologic effects of exposure and interaction were noted. There was no sigificant difference between the level of the nonheme-containing enzyme lactic dehydrogenase in the control and exposed group. Hypertrophy of the heart was noted in embryos exposed to CO for 144 and 168 hours.

Notes: Abstract We discuss the nature of bounds on the error in polynomial interpolation for functions of various degrees of smoothness.

Notes: Abstract Equations are developed to describe the energy expenditure of the human heart. As well as the external potential and kinetic energy terms, general consideration is given to other possible avenues of energy consumption. Emphasis is placed upon using mathematical variables which are readily available for experimental verification. The errors involved in assuming that mean values for the physiological parameters give reasonable estimations for the external mechanical performance are examined, and a theoretical estimation for the discrepancy in the kinetic component is presented. Logical extension of the mathematical derivation leads to a determination of cardiac external mechanical efficiency and clearly demonstrates the significance of the ventricular pressure-volume loop in this context. Finally, experimental procedures are suggested to clarify further some of the conclusions reached through the theoretical analysis.

Notes: Abstract Over sixty syntectonic deformation experiments in uniaxial compression have been done on fine-grained limestones in the stability fields of calcite I, calcite II and aragonite. X-ray techniques and spherical harmonic analysis of the data were used to determine preferred orientation quantitatively, and inverse pole-figures were derived for these axially symmetric specimens. They display in most cases strong preferred orientation which varies as a function of the experimental conditions, mainly temperature and pressure. At temperatures below 350° C recrystallization is lacking and flattened grains indicate that translation, twin gliding and kinking have been the dominant deformation mechanisms. The inverse pole-figure shows a maximum at c with a shoulder towards or a second maximum at e. This is in agreement with preferred orientation observed in experimentally deformed Yule marble and can be explained as the product of dominant twin gliding on e and translation gliding on r (Turner et al., 1956). At high temperatures (900–1000° C) strong grain growth (from 4 to 50 microns) indicates that the fabric recrystallized. Grains are equidimensional and clear with a marble-like texture. The inverse pole-figure shows a single maximum at r, and c-axes are oriented in a small circle around the axis of compression, σ 1. Such a pattern of preferred orientation would be expected on thermodynamic grounds assuming that recrystallized grains will be oriented in such a way that the strain energy is a maximum (e.g. MacDonald, 1960). Decrease in confining pressure caused a decrease of the maximum at c and the formation of a secondary maximum at highangle positive rhombs in the inverse pole-figure. This can be interpreted as r translation dominating over e twinning. In all deformation experiments an equilibrium in preferred orientation was reached after 20 percent shortening. The strength of preferred orientation decreased with increasing temperature. Aragonite was produced within its hydrostatic stability field at temperatures above 500° C. Close to the phase boundary, coarse-grained textures showed preferred orientation with poles to (010) parallel to σ 1. At higher pressures the fabric is fine-grained and [001] is aligned parallel to σ 1. Evidence is given that the phase change from calcite to aragonite in these deformation experiments is a diffusive and not a martensitic transformation.

Notes: Summary Ultrastructural studies of the asexual plurilocular reproductive stages of the brown algaEctocarpus have been made. The zoospores released from the plurilocular sporangia were found to attach to surfaces by means of an adhesive whose site of formation has been shown to be the Golgi apparatus. A preliminary cytochemical investigation has shown that the adhesive contains polysaccharide. This forms the basis for a more precise chemical characterization of the adhesive material.