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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.

Markov chains are central to the understanding of random processes. This is not only because they pervade the applications of random processes, but also because one can calculate explicitly many quantities of interest. This textbook, aimed at advanced undergraduate or MSc students with some background in basic probability theory, focuses on Markov chains and quickly develops a coherent and rigorous theory whilst showing also how actually to apply it. Both discrete-time and continuous-time chains are studied. A distinguishing feature is an introduction to more advanced topics such as martingales and potentials in the established context of Markov chains. There are applications to simulation, economics, optimal control, genetics, queues and many other topics, and exercises and examples drawn both from theory and practice. It will therefore be an ideal text either for elementary courses on random processes or those that are more oriented towards applications.

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.

This article documents the successful development of a computer-assisted process for systematic review of nursing policies and procedures at The Queen Elizabeth Hospital, Toronto, Ontario. Through broad staff input, policies and procedures are research-based yet grounded in the reality of the facility's nursing practice. Client-related standards are written as measurable, realistic statements of desired client outcomes, and as such are standards for client care. Policies and procedures have been rated according to the Canadian Council on Health Facilities Accreditation criteria (client centered, high risk, high volume, problem prone, interservice, outcome-related), so that important policies are easily identified to provide focus for quality assurance activities. The review process is structured so that over the course of a year, all policies are circulated for review by all levels of nursing staff.

Previous studies indicate that limiting tyrosine and phenylalanine intake in the diet decreases tumor growth and metastasis. General health status, immune status, and platelet function were studied in nine healthy human subjects consuming low-protein foods supplemented with formula diets free of tyrosine and phenylalanine to maintain total daily intake of tyrosine at 2.4 mg/kg body wt and phenylalanine at 3.5 mg/kg body wt. This regimen decreased plasma tyrosine (p less than 0.05) but not phenylalanine. Blood indicators of protein status were not changed. Platelet aggregation decreased in response to adenosine diphosphate and platelet activating factor in seven of nine subjects. Natural killer, T-helper, and T-cytotoxic/suppressor lymphocyte numbers proportionally increased relative to neutrophils (p less than 0.05). Natural killer cell activity increased in six of nine subjects. Increased natural killer cell activity and decreased platelet aggregation are two indices associated with decreased tumor growth and metastasis.

Direct probe mass spectrometry of single colonies of different bacteria produced spectra which could be distinguished by calculations based on the intensities of 25 selected ions. Direct probe mass spectrometry has enormous potential as a rapid technique for characterizing micro-organisms.

The discrimination of a set of 53 strains, taken from four closely related Bacillus species (Bacillus subtilis, B. pumilus, B. licheniformis and B. amyloliquefaciens), was examined using pyrolysis mass spectrometry. Strains were grown on six different media to examine the effect of media variation, especially batch-to-batch variation of a single medium, on the pyrolysis mass spectra and strain discrimination achieved. Long-term reproducibility over a period of 14 months was also examined. It was shown that batch-to-batch media variation is insufficient to affect spectra and strain discrimination significantly, but different media types do affect this. It was shown that species groups could still be recovered from the data, however, with an appropriate data-handling system. It was not possible to directly compare spectra produced 14 months apart, but the strain and species discrimination achieved using each data-set were highly comparable.

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.

The electron spin echo modulation spectrum of organic radicals in randomly oriented solids is analyzed in detail for axially symmetric hyperfine tensors. Numerical calculations of the modulation spectra are compared with experimental results from the radical cations of 15N labeled bacteriochlorophyll a and the primary donor of photosynthetic bacterium Rhodospirillum rubrum. Determination of hyperfine coupling constants from experimental spectra in the frequency domain is complicated by the anisotropy of modulation intensity, the effects of second and higher order hyperfine interactions, overlapping spectra from several nuclei, multiple quantum coherences among hyperfine levels, and the spectrometer deadtime. Nonlinear least‐squares analysis of the time domain data [Tang et al., J. Chem. Phys. 83, 4197 (1985)] is the only reliable method for extracting coupling constants from randomly oriented organic radicals.

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.

The design and operation of a time‐resolved electron spin echo spectrometer suitable for detecting transient radicals produced by 3 MeV electron radiolysis is described. Two modes of operation are available: Field swept mode which generates a normal EPR spectrum and kinetic mode in which the time dependence of a single EPR line is monitored. Techniques which may be used to minimize the effects of nonideal microwave pulses and overlapping sample tube signals are described. The principal advantages of the spin echo method over other time‐resolved EPR methods are: (1) Improved time resolution (presently ∼30–50 nsec) allows monitoring of fast changes in EPR signals of transient radicals, (2) Lower susceptibility to interference between the EPR signal and the electron beam pulse at short times, and (3) Lack of dependence of transient signals on microwave field amplitude or static field inhomogeneity at short times. The performance of the instrument is illustrated using CIDEP from acetate radical formed in puls...

The morphology of neurons in the subthalamic nucleus (STN) of the lesser bushbaby (Galago senegalensis) is described in coronal brain sections processed by Golgi- and Nissl-staining techniques. Quantitative and statistical methods are used to evaluate (1) soma size and shape, (2) dendritic field size, shape, and branch frequency, (3) the number of dendritic and somatic spines per neuron, and (4) neuron location within the STN. Principal components analysis of these variables suggests that three classes of neurons are present. Two of these classes are considered to be projection cells, referred to as elongate-fusiform and radiate neurons, respectively. Elongate fusiform neurons have somata and dendritic fields which are large in diameter, extremely fusiform in shape, and give rise to few appendages. Somata and dendritic fields of radiate neurons are smaller in diameter, more rounded in shape, and support more spines than the elongate-fusiform neurons. The third class of cells in Galago STN is tentatively identified as consisting of interneurons on the basis of small soma and dendritic field size, thin and varicose dendritic morphology, and the presence of multilobulated dendritic appendages.

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 Twentyfive separate isolates of serotype 4B of the aerobic sporeforming insect pathogen, Bacillus thuringiensis, have been obtained over the period 1961–68. Most of the isolates of this particular serotype were obtained from storage products insects infesting such places as grain stores, flour mills or ships carrying grain materials. In one instance the organism was isolated from insects infesting Guinea corn growing in the field. In comparison with the other serotypes of this bacillus the association with stored products environments is striking and, on several occasions, it has been possible to trace the distribution of the bacteria by movements of infested materials from one part of the world to another.

SUMMARY Spore, vegetative O and vegetative H agglutinogens were demonstrated as separate entities in Bacillus species. Spore precipitinogens were distinct from those of the vegetative stage, the latter being associated with the H antigen. Injection of viable spores into rabbits resulted in the formation of antibodies for the vegetative phase as well as spore antibodies, while injection of autoclaved spores gave rise to spore antibodies only. Spore agglutinogens varied in their strain specificity, B. cereus and B. megaterium especially showing much subspecies specificity, but the spore precipitinogens showed a high degree of species specificity and could be of considerable taxonomic value. The multiplicity of spore precipitinogens in certain species was demonstrated and inter-species cross reactions were studied.

Summary. Thin sections of methane-utilizing bacteria have been examined in the electron microscope and the fine structure of the cells is described for the first time. The outstanding feature of all the isolates studied is the existence of intracellular membrane structures resembling those seen in nitrifying and photosynthetic bacteria. The possible significance of these membranes is discussed.

Summary The results of an electron microscope survey of flagellation in the genus Azotobacter are presented and the implications of the findings are discussed.

Summary. Forty-six isolates of protein crystal-forming bacteria pathogenic for insects were studied in an attempt to correlate classifications based on biochemical reactions, flagellar antigens, and esterase patterns obtained when cell extracts were analysed by electrophoresis in starch gel. Nine serotypes were represented, one being subdivided into two subtypes on the basis of secondary H antigens. There was a close correlation between the serological classification and that based on esterase analysis. The relationships between the three types of classification are described and the significance of esterase analysis in this context is discussed.

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.