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Plaque formation of phage kappa on Serratia marcescens strain HY normally depends on the presence of either a psi or y prophage in the indicator bacteria. Bacterial ink mutants allowing kappa growth in the absence of either prophage were isolated from the doubly cured strain HY (psi, y)--. By means of a kappa mutant, named gdy, an active participation of kappa in antagonizing inhibition of its own growth on HY (psi, y)-- was demonstrated. The gdy mutation is closely linked to gene cIII coding for the kappa repressor. The prophages psi and y enable kappa to grow undisturbed probably by modifying the kappa DNA during replication in such a way that it is not susceptible to the ink+ effect. Whereas kappa grown on HY (psi, y)--ink-- gave only rare productive infections of HY (kappa, y)--, psi and y grown on the same strain were fully infective. The interference exerted by a kappa prophage on vegetative propagation of y is based upon a multi-component mechanism, the interference being removed, or diminished by mutations residing either inside or outside of the kappa prophage. The responsive phage gene iny+ is dominant over its mutant allele iny--; hence it codes for a diffusible product. Both on the vegetative and the prophage genome iny is located near gene lI responsible for lysogenic conversion of bacteria to non-adsorption of kappa. The restriction-modification system of HY is not involved in the growth inhibition of kappa by HY (psi, y)--. Contrary to the other phages used in this work y is refractory to restriction.

The region of the Mazagan Plateau (Figure 1) offers unique access for Glomar Challenger to document the Jurassic environment of rifting and the early subsidence history of a segment of passive margin bordering the proto-Atlantic. The edge of the Upper Jurassic carbonate platform bulges seaward here from its normal position beneath the present Moroccan continental shelf, and crops out along a spectacular escarpment that falls about 1 km to a broad slope leading to the abyssal sea floor (Figures 2 and 7). The escarpment reveals a section of Mesozoic strata, near the base of which Oxfordian algal limestone has been dredged. With a series of holes drilled near the escarpment, we planned to piece together a composite section that would record the sequence of depo- sitional environments and subsidence history of this thick carbonate platform, including the timing of platform drowing and the installation of pelagic conditions. The results of drilling here bear strongly on the early evolution of the deeply buried conjugate margin on the North American side.

New Hornblende K-Ar and 39Ar-40Ar and mica Rb-Sr and K-Ar ages are used to place specific timemarks on a well-constrained pressure-temperature path for the late Alpine metamorphism in the Western Tauern Window. After identification of excess 40Ar the closure behavior of Ar in hornblende is compared with that of Sr and Ar in phengite and biotite. Samples were collected in three locations, whose maximum temperatures were 570° C (Zemmgrund), 550° C (Pfitscher Joch), and 500-540° C (Landshuter Hütte). The average undisturbed age sequence found is: Phengite Rb-Sr (20 Ma)> hornblende K-Ar (18 Ma)> phengite K-Ar (15 Ma)>biotite Rb-Sr, K-Ar (13.3 Ma)>apatite FT (7 Ma). Except for the phengite Rb-Sr age, the significance of which is debatable, all ages are cooling ages. No compositional effects are seen for closure in biotite. Additionally, Rb-Sr phengite ages from shearzones possibly indicate continuous shearing from 20 to 15 Ma, with reservations regarding the validity of the initial Sr correction and possible variations of the closure temperatures. The obviously lower closure temperature (Tc) for Ar in these hornblendes than for Sr in the unsheared phengites indicates that the T(c sequence in the Western Tauern Window is different from those observed in other terrains. In spite of this discrepancy, valuable geological conclusions can be drawn if the application of closure temperatures is limited to this restricted area with similar T, P and PH2O: (1) All ages of samples located on equal metamorphic isotherms decrease from east to west by about 1 Ma which is the result of a westward tilting of the Tauern Window during uplift. (2) In a PT-path, the undisturbed cooling ages yield constantly decreasing uplift rates from 3.6mm/a to 0.1 mm/a. (3) Use of recently published diffusion data for Ar in hornblende (Tc=520° C) and biotite (Tc=320° C) suggests an extrapolated phengite closure temperature for Sr at 550° C. This suggests that the prograde thermal metamorphism at this tectonic level of the Tauern Window lasted until some 20 Ma ago.

Serratia marcescens HY bacteria must be lysogenic with either prophage y or psi to make it possible for phage kappa to form plaques unless they carry a so-called ink mutation. Genes in y and psi termed any and anp were identified that after infection of ink+ cells are necessary for an effective propagation of these phages as well as of coinfecting kappa phage. When kappa infects y and/or psi-lysogenic cells it transactivates the respective prophage genes by means of two early genes termed tay and tap. It appears that on infection of nonlysogenic ink+ cells kappa damps its own development, provided the regulatory region of the responsible gene is undermethylated. After kappa infection duly to achieve the special methylation of this region seems to be the function of any and anp. There are some more genes in y and psi prophage under the control of tay and tap, concerning in both cases a Dam methylation (recognition sequence GATC) of kappa DNA, a recombination proneness under restricting conditions of kappa DNA not modified by the modification enzyme of HY, and the kappa plaque size. By hybridization studies a region of homology common to y and psi was demonstrated which from its size might comprise all the transactivated genes. The view is supported by genetic data indicating an affinity among the any and anp genes. Investigation of various any mutants were indicative of DNA inversions in this region of the y genome. Surprisingly some of the any mutants had become sensitive in their plaque forming ability to an inhibitory activity exerted by prophage psi. Mutants of psi unable to interfere but still able to lysogenize were isolated. A model is presented accounting for the formation of pleiotropic and nonpleiotropic mutations with Any phenotype and their reversion types. Possible functions of the y genes and their counterparts in psi are discussed.

We examined the mortality rates and causes of death of harbor seal (Phoca vitulina) pups in three regions of the inland waters of Washington (USA) in 1984. One hundred eight pups were collected during 239 searches of the shoreline areas near harbor seal haulout sites or through public reports. Minimum neonatal (up to 1 mo after birth) mortality rates at these regions ranged from 12% to 26% of the pups born. Neonatal mortality was highest in the Strait of Juan de Fuca; 33 of the estimated 105 (31%) pups born at the primary site died. Causes of death varied by location. In southern Puget Sound predation by coyotes (Canis latrans) was the primary cause of death, accounting for eight of 43 (19%) of the dead pups examined; starvation was the next most common cause of death. Mortality at study sites in the Strait of Juan de Fuca was related to premature parturition; 19 of 49 (39%) of the pups found dead were born prematurely. Nine species of bacteria were identified in samples taken from 42 pups; Proteus sp. and Escherichia coli were the most common.

Die Staubentwicklung unter Tage ist fur den Bergmann nicht nur eine Belastigung, sondern auch ein groses gesundheitliches Problem. Die Einatmung des Feinststaubes unter 5 μ, vor allem wenn er einen gewissen Quarzgehalt besitzt, fuhrt nach einer mehr oder minder langen Expositionsdauer zu schweren Staublungenerkrankungen. Da man annahm, das der Feinststaub von 1–5 μ am gefahrlichsten ist, wurden bei der Staubbekampfung und Staubmessung vor allem diese Korngrosen berucksichtigt. In den letzten Jahren hat man aber in den Lungen von Bergleuten, die an Pneumokoniose verstorben waren, vorwiegend Staube unter 1 μ gefunden. Auf dem europaischen Kongres fur Elektronenmikroskopie in Stockholm wurde von Schlipkoter und Colli uber elektronenoptische Untersuchungen von Staubkorngrosen in Staublungen berichtet. Hierbei ergaben sich fur die Lange der Staubpartikel Korngrosenmaxima zwischen 0,15 μ und 0,35 μ. Wir haben deshalb darauf hingewiesen, das man bei einer Staubbekampfung auch die Feinststaube unter 0,5 μ berucksichtigen mus.

An isolierten elektrisch gereizten linken Vorhofen von Meerschweinchen wurde die Refraktarzeit durch gepaarte Stimulation bestimmt und die Kontraktionskraft nach einfacher und doppelter Reizung isometrisch registriert (Versuchstemperatur 30° C).

Die Staubentwicklung unter Tage ist fur den Bergmann nicht nur eine Belastigung, sondern auch ein groses gesundheitliches Problem. Die Einatmung des Feinststaubes unter 5 µ, vor allem wenn er einen gewissen Quarzgehalt besitzt, fuhrt nach einer mehr oder minder langen Expositionsdauer zu schweren Staublungenerkrankungen. Da man annahm, das der Feinststaub von 1–5 µ am gefahrlichsten ist, wurden bei der Staubbekampfung und Staubmessung vor allem diese Korngrosen berucksichtigt. In den letzten Jahren hat man aber in den Lungen von Bergleuten, die an Pneumokoniose verstorben waren, vorwiegend Staube unter 1 µ, gefunden. Auf dem europaischen Kongres fur Elektronenmikroskopie in Stockholm wurde von Schlipkoter und Colli uber elektronenoptische Untersuchungen von Staubkorngrosen in Staublungen berichtet. Hierbei ergaben sich fur die Lange der Staubpartikel Korngrosenmaxima zwischen 0,15 µ und 0,35 µ. Wir haben deshalb darauf hingewiesen, das man bei einer Staubbekampfung auch die Feinststaube unter 0,5 µ berucksichtigen mus.

ALPHA-PARTICLES are very strongly absorbed even by thin layers of materials. Their path through matter is almost exactly a straight line, and their effect on a photographic emulsion is very strong. These properties seem to be well suited for micro-radiographic mass determinations. Since such methods promise to be of value in several research fields, such as biology, medicine, mineralogy and metallurgy, experiments have been undertaken to determine the potentialities and optimal conditions for alpha-microradiography. The main advantage of using alpha-particles as compared with soft X-rays1 would be the much simpler apparatus needed and the relative independence of the absorption on the composition of the object.

Exact similar and nonsimilar solutions for axisymmetric wakes with small swirl in a constant‐property medium are derived. Emphasis is placed on the similar solutions, particularly those associated with the swirl. A unique similar solution for the axial velocity is distinguished from a possible infinite set by invoking the auxiliary condition of invariance of the axial momentum defect. Likewise, for the circumferential velocity only one of the large number of possible similar solutions is shown to satisfy the conditions that the circumferential mass flow, momentum flux, and higher moments are bounded.