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Clouds play an important role in the climate system by reducing the amount of shortwave radiation reaching the surface and the amount of longwave radiation escaping to space. Although dependent on type and location, clouds produce more cooling than warming in the global average. Accurate simulation of clouds in computer models remains elusive, however, pointing to a lack of understanding of the connection between large-scale dynamics and cloud properties. This study uses a k-means clustering algorithm to group 21-years of satellite cloud data over midlatitude oceans into seven clusters and demonstrates that the cloud clusters are associated with distinct large-scale dynamical conditions. Three clusters correspond to low-level cloud regimes with different cloud fraction and cumuliform or stratiform characteristics, but all occur under large-scale descent and a relatively dry free troposphere. The "small cumulus" regime is most prevalent equatorward of 40° in all seasons; the "large cumulus" regime is associated with a relatively cold troposphere and primarily occurs during winter; and the "stratocumulus/stratus" regime occurs under a temperature inversion and relatively warm free troposphere and predominates during summer. Three clusters correspond to vertically extensive cloud regimes with tops in the middle or upper troposphere. They differ according to the strength of large-scale ascent and enhancement of tropospheric temperature and humidity: "deep altostratus" has the smallest forcing, "weak frontal" is in the middle, and "strong frontal" has the largest forcing. The frontal cloud regimes occur most frequently in storm track regions. The final cluster, "cirrus" is associated with a lower troposphere that is dry and an upper troposphere that is moist and experiencing weak ascent and horizontal moist advection. This information builds a foundation for producing an observational estimate of the midlatitude ocean cloud response to warming that is independent of confounding meteorological influences.

We consider a stochastic particle model for coagulating particles, whose free motion is Brownian, with diffusivity given by Einstein's law. We present in outline a derivation from this model of a spatially inhomogeneous version of Smoluchowski's coagulation equation. Some analytic results on existence, uniqueness and mass conservation for the limit equation are also presented.

A structural study based on EXAFS, FTIR, and optical absorption spectroscopies has been conducted on a photogenerated, metastable state of cyclopentadienylnickelnitrosyl (CpNiNO) produced by a reversible photochemical reaction. The photogenerated, metastable state with distinctively different EXAFS, IR, and optical absorption spectra from those of the ground state molecules was created by irradiating the sample with the 365 nm line of a mercury lamp at 20K . At the same temperature, the reverse reaction was induced by irradiation with the 313 nm line from the mercury lamp. Based on the analysis of the EXAFS data, the photogenerated, metastable state of CpNiNO has undergone considerable nuclear rearrangements compared to its ground state. The nuclear movement is characterized by a 0.12{angstrom} elongation of Ni-N bond and by a bending of Ni-N-O. A shift of the N-O stretching frequency from 1824 to 1387 cm{sup {minus}1} was observed in the photoinduced reaction with 365 nm light, implying that a NO{sup {minus}} like species results from intramolecular electron transfer from Ni to NO. The changes in the absorption spectra for the same reaction showed reduced absorption of the 385 nm band and a newly generated broad band near IR region. Temperature dependence of the Debye-Waller factor of CpNiNO was in good agreement with the diatomic harmonic oscillator for the Ni-N bond, but deviated for the Ni-O and the Ni-C bonds. Based on the structures obtained from EXAFS, ZINDO calculations for both the ground state and the photogenerated, metastable state of CpNiNO reproduced the general features of the observed absorption spectra and qualitatively explained the wavelength dependence of the reaction. The calculated partial charges on each atom in the ground state and the photogenerated, metastable state of CpNiNO are consistent with intramolecular electron transfer upon photoexcitation by 365 nm light.

Nine strains of Bacillus mycoides, 10 of Bacillus cereus and 18 of Bacillus thuringiensis were analysed using pyrolysis gas—liquid chromatography. Application of canonical variates analysis to the resultant pyrograms showed that these organisms formed three distinct groups. Stepwise discriminant analysis with jacknifing showed that of the original 27 peak heights used to define the canonical variates axes, only two were needed to obtain reasonably stable discriminant functions. These discriminant functions (Dixon, 1975) are potentially valuable in identification. Jacknifing also indicated that, had it been an unknown, one strain of B. mycoides would have been incorrectly identified as B. cereus.

Eight strains each of Bacillus subtilis, Bacillus pumilus, Bacillus licheniformis, and Bacillus amyloliquefaciens were analyzed by using pyrolysis gas-liquid chromatography. Statistical analysis with canonical variates gave four well-separated groups, which represented the four species. Further analysis of the same strains by deoxyribonucleic acid-deoxyribonucleic acid hybridization and API identification systems confirmed the discrimination obtained with pyrolysis gasliquid chromatography. However, analysis by biochemical tests performed in the classical way gave only three groups since it was not possible to achieve separation of the strains representing B. subtilis from those of B. amyloliquefaciens when these tests were used.

SUMMARY: The existence of subgroups within Bacillus megaterium has been reported previously on the basis of DNA-DNA hybridization and DNA base composition studies. In this study the strains used to define these subgroups have been reanalysed by pyrolysis gas-liquid chromatography. The resultant two-group classification of the test strains was directly comparable with that obtained from the previous nucleic acid analyses at the between-group level. However, comparisons of the test strains at the within-group level proved less successful.

SUMMARY: A lytic principle associated with cultures of Bacillus cereus is described and some of its properties discussed. The principle is relatively non-specific, acting on several species of aerobic spore-formers. It has properties in common with similar agents reported recently and comparisons with these are made. Lysis results in the loss of cell contents whilst at least part of the cell-wall structure remains intact.

Crystalline inclusion bodies resembling those seen in Clostridium cochlearium were detected in cultures of Bacillus thuringiensis infected with bacteriophage.

SUMMARY: The ‘negative contrast method’ was used to study by electron microscope four previously described Bacillus cereus bacteriophages. The main features of the structure of these phages are described and the observations corrected with similar work on phages associated with other genera.

SUMMARY: The use of pyrolysis mass spectrometry in the characterization and identification of Bacillus species was studied. Fifty-three strains of four closely related groups, Bacillus subtilis, B. pumilus, B. licheniformis and “B. amyloliquefaciens”, were used in a study of both sporulated and non-sporulated cultures. Pyrolysis was carried out using a Pyromass 8-80, a novel pyrolysis mass spectrometer specifically designed for fingerprinting complex samples. The pyrolysis data obtained were analysed using multivariate statistical techniques. All four groups could be differentiated using data from non-sporulated cultures but the data from sporulated cultures did not separate B. subtilis from “B. amyloliquefaciens” or B. pumilus. In contrast, B. licheniformis was more clearly differentiated from the other three species using these data. Culture maturity affected the mass spectra obtained from non-sporulated cultures.

High-resolution pyrolysis gas-liquid chromatography was applied to three bacteria (Escherichia coli NCTC 9001, Pseudomonas putida (NCIB 9494, and Staphylococcus aureus NCTC 8532) grown under a variety of conditions. Changing the culture medium drastically altered the quantitative aspects of the pyrograms of all three organisms, but the effects of culture time and incubation temperature were less severe. Mathematical analysis of the relative peak heights showed that four peaks could be used to discriminate the three bacteria however they were cultured.

Low resolution pyrolysis gas-liquid chromatography could differentiate the following groups of Clostridium botulinum and related organisms: (1) Cl. botulinum type A. proteolytic types B and F and Cl. sporogenes; (2) Cl. botulinum types C and D. and (3) Cl. botulinum type E and non-proteolytic types B and F. Toxin types A and B could be distinguished from type E and from type F.

Baillie, Ann (University of Glasgow, Glasgow, Scotland), and John R. Norris . Antigen changes during spore formation in Bacillus cereus . J. Bacteriol. 87: 1221–1226. 1964.—Ultrasonic extracts of Bacillus cereus cells harvested at different stages in spore formation were analyzed by immunoelectrophoresis with antisera prepared by injecting similar extracts into rabbits. Seven antigens resistant to heating at 80 C for 10 min were detected in extracts of young vegetative cells, and there were at least eight additional thermolabile antigens present at this stage. During spore formation, many of the thermolabile antigens disappeared from the cells and new antigens could be detected. Mature spores contained four of the heat-resistant antigens present in young vegetative cells and an additional five heat-resistant antigens. Only three thermolabile antigens were detected in spore extracts.

SUMMARY Four phages isolated from bacteria of the Bacillus cereus group are described. They show cross-reactions between crystal-forming and non-crystal-forming strains which are deficient in ability to produce a lecithinase C. The implications of this finding are discussed.

SUMMARY: Agglutinogens and precipitinogens have been detected in the spores of many species of aerobic and anaerobic spore-formers and these antigens are distinct from those of the vegetative growth phases of the corresponding organisms. Spore antigens are heat resistant and antibody response is elicited by the injection of autoclaved spores into rabbits. Injection of living spores leads to the development of antibodies reacting with vegetative cell antigens in addition to spore antibodies. Agglutinogens tend to show subspecies distribution in some aerobic species but spore precipitinogens appear to be mainly species specific in aerobes. Less information is available about anaerobes where a similar pattern of specificity is suggested. Data about the antigenic structure of the spore and the antigenic changes accompanying sporulation and germination are scant; it is in these aspects of the subject that the most significant progress is to be anticipated.

PREVIOUS attempts at studying the antigens of Azotobacter have met with only limited success. Azo and Yoshida in a brief report1 described complement-fixation by Azotobacter cells in the presence of specific antisera but gave few experimental details. Jensen and Petersen2 obtained an agglutinating antiserum for Azotobacter chroococcum. Recently, Petersen3 studied the agglutinogens of Az. chroococcum, Az. vinelandii, and Az. agilis. Az. chroococcum and Az. vinelandii had antigens in common and showed serological affinities to Beijerinckia sp. Az. agilis appeared to be antigenically distinct. Eisenstark et al., on the other hand, using apparently adequate technical methods, failed to produce antisera to Az. agilis or “numerous other azotobacter species”. Heidelberger (quoted in Lawson and Stacey5) showed Az. chroococcum polysaccharide to be antigenic.