Type Sbc Research Articles

Star formation activity in spiral galaxy disks and the properties of radio halos: Observational evidence for a direct dependence

In this article we address observationally the questions: how does star formation (SF) in the disks of galaxies lead to the creation of radio halos, and what minimum energy input into the interstellar medium (ISM) is needed to facilitate this? For the investigation we use a sample of five edge-on galaxies exhibiting radio continuum emmission in their halos and enhanced SF spread over large parts of their disks. In a detailed study of the two galaxies in our sample for which we have the best data, NGC 891 and NGC 4631, we show that the radio halos cut off abruptly at galactocentric radii smaller than those of the underlying thin radio disks. Our most important result is that the halo cutoffs are spatially coincident with the radii where the SF activity in the underlying disks drops sharply. The difference in radius of the emission distributions tracing ongoing SF in the disks (IRAS 50 micrometers, H alpha) versus that of the nonthermal radio continuum thin disks (tracing the distribution of cosmic-ray (CR) electrons) is typically a few kpc. This difference in extent is caused by CR diffusion. We have measured the CR diffusion coefficients in the thin disks of both NGC 891 and NGC 4631. For radial diffusion of CR electrons within the galactic disks the values are D(sub r) = 1.1-2.5 x 10 (exp 29) sq cm/s (NGC 4631) and D(sub r) = 1.2 x 10(exp 29) sq cm/s (NGC 891). For motions in the z-direction in areas within the thin disks where no outflows occur, we derive a firm upper limit of D(sub z) less than or equal to 0.2 x 10(exp 28) sq cm/s for NGC 891. The value for NGC 4631 is D(sub z = 1.4 x 10 (exp 28) sq cm/s. The other three galaxies in our sample, NGC 3044, NGC 4666, and NGC 5775 show (at the sensitivity of our data) less extended, more filamentary radio halos. Isolates spurs or filaments of nonthermal radio continuum emission in their halos are traced only above the most actively star-forming regions in the disks. This, in conjuction with the results obtained for NGC 891 and NGC 4631, suggests a direct connection between the shapes and radial extents of radio halos of normal galaxies and the level and the spatial distribution of the current SF in their disks. The existence of filamentary structures implies that expansion and convection of CR-heated plasma plays an important role even at low z-distances above the plane. Based on radio data we derive the disk-averaged mean energy input rates into the ISM due to supernova explosions per unit surface area in nine galaxies, including the ones in our sample. We find a clear trend in the sense that the galaxies with the highest mean energy input rates in the underlying disks have the most extended and pervasisve radio halos. Below a certain threshohld, outflows are inhibited. As a lower limit for this threshhold we derive an energy input rate of approximately 10 (exp -4) erg/s sq cm. The fact that radio halo emission is found only above the most luminous giant H 2 regions in late-type 'normal' galaxies (of type Sbc or later) indicates that only these are capable of initiating disk-halo interactions by locally exceeding the threshold. The distribution of the local outflows determines the overall shapes of the CR halos and leads to the observed filamentary structures.

Developmental disorders of skin potential responses in mentally retarded children during nocturnal sleep

Skin potential responses (SPRs) of 89 mentally retarded children were studied during their nocturnal sleep. Forty-three out of the 89 subjects showed more SPRs (type A) during NREM sleep than in REM sleep. The opposite was observed in 10 cases (type C), and 4 had evenly distributed SPRs during both sleep phases (type B). The remaining 32 subjects had mixed types AB (n = 19), AC (n = 6) or BC (n = 7). Types B and C (including the mixed type) were observed more frequently for subjects with low developmental quotient (DQ) and abnormal clinical EEGs than for those with high DQ and normal clinical EEGs. Since it has been well established that normal subjects of 3 months and over exhibit exclusively type A, SPRs may be used as an additional tool for the diagnostic assessment of mental retardation in early infancy.

Geographical distribution of landrace groups classified by hybrid pollen sterility in foxtail millet, Setaria italica (L.) P. Beauv.

Eighty-three strains of Setaria italica collected from various areas throughout Eurasia were crossed with three tester strains from Japan (tester A), Lan Hsu Island of Taiwan (B) and Belgium(C). The F1 hybrids were obtained in 224 of the 249 cross combinations tried. The pollen fertility of the F1 hybrids ranged widely from almost sterile (8.2%) to highly fertile (99.1%) while there was a little variation among the individual F1 plants of the same cross combination. The 62 strains, which successfully produced F1 hybrids with all of the three testers, could be clearly classified into six types, designated as types A, B, C, AC. BC and X. Pollen fertility of more than 75% was regarded as normal. The strains of types A, B and C were those which produced F1 hybrids having normal pollen fertility when crossed with testers A, B and C, respectively. When both F1 hybrids from the crosses with two testers, A and C, or B and C, showed normal pollen fertility, the strain was classified as type AC or BC. The strains whose F1 hybrids always showed pollen fertility of less than 75% in all three cross combinations were designated as type X. There was no strain whose F1 hybrids always showed normal pollen fertility in the cross combinations with all three testers or both testers A and B. These types classified are thought to reflect the landrace groups phylogenetically differentiated, because hybrid sterility occurs as the results of genetic differentiation between strains. Most type A strains were distributed in East Asia including Japan, Korea and China. Type B strains were narrowly found in Taiwan and in the southwestern part of the Nansei Islands of Japan. Most European strains were found to be type C. Strains of types AC and BC were distributed in Afghanistan and India, respectively. Types AC and BC are thought to be less specialized genetically than A, B or C. The geographical distribution of these landrace groups suggests that S.italica was first domesticated in an area ranging frorn Afghanistan to India, and then dispersed both eastward and westward from there.

The morphological types and orbits of H I-deficient spirals in clusters of galaxies

view Abstract Citations (73) References (24) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS The Morphological Types and Orbits of H i Deficient Spirals in Clusters of Galaxies Dressler, A. Abstract Further analysis of the Giovanelli and Haynes catalog of the H I content of cluster spirals reveals that H I deficiency is strongly correlated with morphological type. Those spirals deficient in H I are predominantly early-type galaxies; spirals of type Sbc and later are rarely found to be gas deficient, even though they often reside in the same dense environments. Comparison of the velocity dispersion as a function of radius for gas-poor and gas-rich spirals indicates that the gas-poor spirals are on radial orbits which carry them into the dense environment of the cluster core, while the orbits of gas-rich spirals are more likely to be isotropic or even circular. The simplest interpretation of these data is that ram pressure stripping of spiral galaxies on radial orbits is responsible for H I deficiency. Publication: The Astrophysical Journal Pub Date: February 1986 DOI: 10.1086/163868 Bibcode: 1986ApJ...301...35D Keywords: Galactic Clusters; Galactic Structure; Hydrogen Clouds; Interstellar Gas; Orbital Mechanics; Spiral Galaxies; Galactic Evolution; Radio Galaxies; Astrophysics; GALAXIES: CLUSTERING; GALAXIES: STRUCTURE; INTERSTELLAR: MATTER; RADIO SOURCES: 21 CM RADIATION full text sources ADS | data products SIMBAD (8) NED (5)

THE TWO SUPERPOSED GALAXIES OF NGC 3314.

ABSTRACT Spectroscopic observations of NGC 3314 are presented. Long-slit spectrograms clearly show two sets of emission lines stemming from the two superposed galaxies. The foreground galaxy, NGC 3314a, is a type SBbc or SBc spiral of absolute magnitude MB ≈ -20 and has a radial velocity czsun; = 2835±15 km s-1. The background galaxy, NGC 3314b, is probably an Sb of MB ≈ -20.5 with czsun; = 4641±6 km s-1. The availabe evidence suggests that at least NGC 3314a, and probably also NGC 3314b, are members of the Hydra I cluster of galaxies (czsun; = 3699 km s-1, σv = 681 km s-1), although the alternative hypothesis that one of them or both are field galaxies cannot presently be ruled out.

CO (2–1) observations of Maffei 2

Maffei 2 is a highly obscured galaxy, probably of type Sbc, at a distance of 5 Mpc (Allen and Raimond 1972; Spinrad et al. 1973). Since it lies close to the Galactic plane, there is considerable confusion in infrared and 21-cm HI observations due to Galactic emission, but investigations of its structure can be carried out at millimeter wavelengths where the Galaxy contribution is confined to a limited velocity range. The high resolution (30″) of our CO J=2–1 observations permits both a detailed examination of Maffei 2 and a study of the nature of the gas in its nucleus, through comparison with the CO J=1–0 observations.

Isolation of enterotoxigenic strains of staphylococci from dogs

The ability of 309 staphylococcal isolates from household dogs to produce enterotoxin, coagulase, thermonuclease and hemolysin was investigated. A total of 52 (16.8%) isolates from 45 out of 150 dogs examined were enterotoxigenic when tested for enterotoxin types A, B and C. Based on sites sampled, 33 (20.5%) out of 161 isolates from the anterior nares were enterotoxigenic while from dorsal skins 19 (12.8%) out of 148 isolates were enterotoxigenic. Staphylococcal enterotoxin C(SEC) was predominantly produced as 21 (6.8%) isolates elaborated it and also accounted for 40.4% of all enterotoxins produced by isolates. Staphylococcal enterotoxins A(SEA) and B(SEB) were produced by 10 (3.2%) and 16 (5.2%) strains, respectively. Mixed enterotoxin types AB, AC and BC were produced by 1,3 and 1 strains, respectively. With human plasma, 17.1% of coagulase-positive and 15.0% of coagulase-negative strains were enterotoxigenic. However, using canine plasma, 19.1% and 6.9% of the coagulase-positive and negative isolates, respectively, were enterotoxigenic. The incidence of enterotoxigenicity was 16.9% amongst thermonuclease-positive isolates and 16.3% for thermonuclease-negative strains. Alpha hemolysin was predominantly produced by 180 (60.2%) isolates and 19.9% of these were enterotoxigenic. Beta hemolysin was produced by 36 (11.7%) isolates with 13.9% enterotoxigenic, while 87 (28.2%) exhibited gamma hemolytic pattern amongst which 11.5% were enterotoxigenic. Based on data provided on coagulation of human and canine plasmas and hemolytic patterns, it is concluded that a large proportion of canine isolates from this environment are not of canine biotypes, but are most probably human biotypes.

The subgenus Persicargas (Ixodoidea, Argasidae, Argas). 15. Histology and histochemistry of the salivary glands of A. (P.) persicus (Oken).

The salivary glands of Argas (Persicargas) persicus (Oken) consist of 2 types of alveoli. Type A alveoli, aggregated around and directly connected to the main salivary duct through shorter alveolar ducts, appear syncytial with finely granulated, fibrillar cytoplasm, and 1 large and several small nuclei. The cytoplasm contains proteins and phospholipids and fine PAS-positive granules. Type B alveoli, connected by branching secondary alveolar ducts to the main salivary duct, are formed of 3 cell types (Ba, Bb, and Bc) representing synthetic sites for at least 3 functional salivary components. One or 2 Ba cells at the alveolus base contain PAS-positive granules rich in tryptophan-containing proteins, and phospholipids. Two or more Bb cells next to Ba cells secrete granules containing neutral mucopolysaccharides and proteins rich in tyrosine. The others are Bc cells containing large PAS- and protein-positive globules showing a moderate degree of metachromasia. Histochemical tests suggest that Ba cell secretion may contribute a pharmacologically active substance to the saliva. Bb cells may produce a lytic salivary component. Bc cells may produce a moderately sulphated anticoagulant which becomes active as the tick feeds. Type A alveoli probably contribute watery secretions to the saliva. The results show that the 3 cell types are not different steps in secretion of a single salivary substance, as believed by previous workers.

Secular Fluctuation of the October Precipitation in the Carpathian Region of the Danube Basin

There appears an ever increasing need of studying not only the changes of values of climatic elements but also the changes of their annual variation. A convenient method of satisfying this need is the study of the principal singularities of the weather and of the singularities of individual climatic elements. Apart from purely synoptic analyses and the formal study of secular series of climatic elements, studies concerning the values of climatic elements and their dependence on the changes of factors of the atmospheric circulation as well as research into the geographical laws governing these changes are also most necessary. An analysis of the annual variation of precipitation in Brno has shown that this annual variation is very different in the successive distinct periods (1851/1875, 1876/1900, 1901/1925, 1926/1950) of the past one hundred years. An analysis of the annual variation in other European stations has confirmed the reality of these changes throughout Europe. We have analysed more fully the changes in the variation of autumn precipitation, and particular attention has been paid to the October precipitation in the Carpathian part of the Danube basin for the period 1901/50, from which the necessary synoptic and meteorological material is already available. In the annual variation of precipitation in this region there occurs a secondary October, or November, maximum. The principal cause of increased precipitation in October is the intensive precipitation of certain synoptic situations, which can be characterized (according to the catalogue of P. Hess and H. Brezowsky) as (GT) types TM, NW, E, SE+S, or (according to Fr. Rein an M. Konček's catalogue) as types Bc, Cc, Ec, SWc2 and NWc. Increased frequency of these situations occurs at the beginning and towards the end of the month of October. Diurnal totals of precipitation in these situations are so great that October registers a high monthly total, although most days in October have otherwise low diurnal amount of precipitation. In the diurnal variation of the October precipitation amounts a significant change has also taken place during the past fifty years. Thus, in the period 1901/1925, the maximum of precipitation occurs at the beginning of the month (about October 5th) and towards the end of the month there is little rainfall; in the period 1926/1950 the amount of precipitation is small at the beginning of the month and the maximum occurs towards the end (about October 25th). In both cases the minimum of precipitation occurs in the middle of the month (about October 15th). A change in the period referred to has also taken place in the variation of synoptic situations. The variation of precipitation is not much affected by the most frequent synoptic types W(GT) and HM(GT), but it agrees strikingly with the variation of otherwise infrequent situations, such as TM and NW. The last two situations should be regarded as the cause of the October precipitation singularities referred to. The variation of precipitation in Hungary and in the greater part of the Rumanian territory has similar characteristics as in Czechoslovakia. But there appears also a secondary maximum at the end of the month in the period 1926/1950. Southern and eastern Rumania has a different regime of precipitation. The above mentioned three distinct (in regard to precipitation) sections of October, which roughly coincide with three October decades, have been analysed according to the degree of similarity in precipitation. The synoptic basis of this method has been justified by M. Bouët, and in our study we have only modified the conditions for its climatological application. The maps of the degrees of similarity demonstrate that the region of moderate to considerable degree of similarity covers roughly the basin of the rivers Morava and Vah with Nitra and also north-~ astern and central Hungary. The remaining regions show a low degree of similarity or have an indifferent or even opposite regime of precipitation. In the above mentioned region there occurs roughly the same climatological fluctuation of the precipitation regime. Research of this type is important for a dynamic conception of the term of physiographical milieu in which a change of the precipitation regime affects changes in the hydrological regime with all consequences for biogeographical conditions. Besides its contribution to the theory of climate and to the rising science of climate forecast it is of great value for studies concerned with methods of climatological classification.

Ionized Gas in Spiral and Irregular Galaxies.

view Abstract Citations (141) References (35) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS Ionized Gas in Spiral and Irregular Galaxies. Burbidge, E. Margaret ; Burbidge, G. R. Abstract The distribution of ionized gas as deduced from the emission lines seen with the nebular spectrograph is described for more than 30 spiral and irregular galaxies. From the comparison of estimates of the relative intensities of Ha and [N ii] X 6583, with relative intensities computed by the usual techniques, it is concluded that the major regions of emission in the outer parts of galaxies and in the spiral arms, where the Ha/[N ii] X 6583 ratio is 3, are similar to the extended H ii regions first discovered by Struve and Elvey in our own Galaxy. The investigation has substantiated the result that irregular galaxies have the highest proportion of ionized gas and that this decreases steadily through barred spirals of types SBc and SBb and normal spirals of types Sc, Sbc, Sb, and Sa. Throughout irregular galaxies and in the nuclear, as well as the spiral-arm, regions of SBc and SBb galaxies and some Sbc and Sc galaxies there must be a considerable population of massive luminous stars. The nuclei of other Sc and Sbc galaxies and the nuclei in the majority of Sb galaxies contain less ionized gas than do the spiral-arm regions. The most striking observational result is that between the outer parts and the nuclear regions in many of these latter galaxies the ratio of the strengths of Ha and [N ii] X 6583 decreases from about 3 to values in the range 10.1. This reversal is most common in Sb and Sa galaxies with large prominent nuclei and well-developed nuclear bulges, but it appears even in some Sc galaxies with small nuclei. This can be explained either by a general deficiency of hydrogen in these regions (which we think improbable) or by supposing that radiative processes are comparatively unimportant in those nuclei where the light comes mainly from K giants, and that collisional ionization and excitation take place in the gas with an electron temperature of , or with energies of a few electron volts, since such excitation may be non-thermal. These excitation conditions might arise through corpuscular radiation from . Whether such an explanation for the anomalous ratios is accepted depends on the energy balance, i.e., estimates of the energy supply required to maintain such a high electron temperature against cooling mainly by line emission. This will require absolute measurement of emission4ine intensities. Publication: The Astrophysical Journal Pub Date: May 1962 DOI: 10.1086/147313 Bibcode: 1962ApJ...135..694B full text sources ADS | data products SIMBAD (42) NED (36)