ALBERT

Notes: Summary Cephalotes atratus, the “giant turtle ant” of the Neotropical tribe Cephalotini, exhibits an intermediate stage in the evolution of polymorphism. The allometric growth line is straight, but the distribution of worker sizes is bimodal. An ethogram of workers in laboratory nests showed pronounced differences in behavior according to age. Under natural conditions, individual foraging specializations based on worker size were also found. Compared to other advanced cephalotines, this species appears to be less strongly adapted for arboreal life. A model is presented for the evolution of polymorphism in ants.

Notes: Summary In females ofPolistes gallicus the activity of corpora allata (CA) was determined volumetrically as well as radiochemically using the in vitro assay for juvenile hormone (JH). The results we have compared with the ovarian activity. During the period of egg maturation after overwintering the volume of CA is well correlated with the synthetic activity. But in overwintering females and in ovariectomized females we have observed very large glands which produced only little amounts of JH like the small glands of parasitized wasps. In all dominant females the CA we have found to be larger and more active than in subordinated females indicating that changes in the endocrine activity may be a primary result of social hierarchy.

Notes: Summary The colony-moving ofMyrmica rubra L. was induced in he laboratory by worsening the microclimate of the nest. A detailed analysis of the whole process is given; it is based both on observation and on traffic measurements between the old and the new nests. Three periods can be recognized: exploration, emigration, and final exploration. Two recruitment methods occur, initiated by distinct motor displays: group recruitment takes place first, whilst carrying behaviour becomes the main technique later. The organization of the group is described. The recruiter extrudes its sting while returning to the old nest and while leading the group. Tracks left on soot-coated glasses are analyzed. Sticks crushed with either the poison gland or the Dufour's gland are effective in leading the ants. Most adult carrying postures are typical for myrmicines: the occurrence of atypical postures is discussed. All the carrying acts (of brood and adults) are effected by 25% of the workers (on average); carrying activity is age-dependent. The stability of the group of carriers is tested during successive emigrations. Social regulation potentiality is strong: even queens or callows can move with their larvae when isolated from the rest of the colony.

Notes: Summary The reproductive rate of unmanaged European honeybee races was studied in Kansas, U.S.A. Colonies produced a mean of 3.6 daughter colonies per original queen during one year. This high reproductive rate was largely due to the frequent occurrence of afterswarms, a factor not adequately considered in previous studies. The rate of afterswarming was influenced by at least two factors: the amount of sealed brood (pupae) in the colony and the season when swarming occurred. Factors which may influence the survival and subsequent reproduction of prime swarms and afterswarms are discussed.

Notes: Abstract The integral equation for the electromagnetic response of a sphere in a layered medium may be solved as follows. First, the unknown time harmonic electric field in the sphere is expanded in spherical vector waves. Secondly, the coefficients for these wave functions are found by a set of equations. The equations are found by multiplying the integral equation throughout by each wave function and integrating over the spherical conductor. Once the unknown coefficients have been determined, then the transient response may be found by taking the inverse Fourier transform. In carrying out the Fourier transform one learns that for most of the time range used in prospecting, only the lowest order vector wave function is significant. A study of the singularities of the spectrum of the transient shows that, for the time range considered, only a single branch cut is significant. There are no pole type responses. That is, the field does not decay exponentially. Previous studies of a sphere in free space reported only pole type responses. That is, at the later stages, the field decays exponentially. This study shows that, in order to model satisfactorily the effect of the host rock on transient electromagnetic fields, the sphere must be placed in layered ground.

Notes: Abstract Tidal records at Hanasaki, southeastern Hokkaido, are analysed to clarify the post-seismic crustal vertical movement in the 1973 Nemuro-oki, Japan, earthquake. The result shows that the post-seismic uplift, as speculated byKasahara (1975), terminated in late 1975 and reverted to the previous rate of rapid subsidence of about 1 cm/yr. Ceasing of the post-seismic uplift, which occurred much earlier than previously speculated, could be explained by supplementary mechanisms, such as frictional resistance against creeping at the fault surface. This unexpected mode of movement, however, raises a new question about the accumulation of tectonic movements in this district. Since the subsidence rate extrapolated from geomorphological data for the past several thousand years is almost one order of magnitude lower than the recent rate as mentioned above, we have to provide some alternative explanation for the discrepancy between the two rates. In other words, simple repetition of co-, post- and inter-seismic movements in seismic cycles due to plate subduction, must be modified in this district. Several possible modifications to the subduction process are suggested, and a brief discussion of vertical movements expected in each case is given.

Notes: Abstract Recent advances in the use of dynamical and statistical models to forecast the weather are described. High resolution physical-mathematical models can now predict the development of synoptic weather systems in great detail for a few days ahead, while large-scale phenomena like blocking can be predicted for about a week or more. The local forecasting problem is presently being attacked by statistical- and meso-scale models using the large-scale predictions as input parameters. Very encouraging results have been obtained to predict the local weather, in particular when the local weather is influenced by topography and the underlying surface.

Notes: Abstract In recent years there has been much progress in describing and understanding the detailed dynamical and microphysical structure of frontal precipitation systems. In this article we consider phenomena on a hierarchy of scales: the broad synoptic-scale flows in mid-latitude depressions, the mesoscale patterns of precipitation, the nature and origin of convection at the surface and aloft, and the microphysical properties of the resulting precipitation. The influence of orography is also briefly discussed.

Notes: Abstract Spectral analyses were made of derived area-index series of areas subject to extreme temperatures and precipitation as well as cross-spectral analyses of the area-index series with double sunspot cycle (Zurich) numbers. Superposed epoch analyses also were made of area-index series versus various double-sunspot cycle phases. Area series for wet and dry Junes, warm Junes, defined June drought, and warm Januaries all show statistically significant double sunspot cycle (∼21 year) periodicities. The 21-year cycle of above-normal June precipitation is most striking and has not received previous recognition.

Notes: Abstract An examination is made of the hypothesis that internal cloud properties are determined by the mixing of dry air from above the cloud top and cloud base air in such a way that the mixture is neutrally buoyant with respect to the clear air environment at each level. It is concluded that the resulting mixture is much drier than is actually observed. Comments are made about observed cloud properties which need to be taken into account in any model of the mixing process.

Notes: Abstract Riming growth of ice particles is simulated by numerically solving the stochastic collection equations, simultaneously considering coagulation of water droplets. By introducing a special criterion which defines the habit of a riming particle, the influence of this habit on the growth of several kinds of ice particles assumed to be formed during riming was investigated. It was found that (i) hexagonal rimed ice plates are growing more efficiently than lump graupel or rimed columns, (ii) the use of different collection kernels for the lump graupel evolution leads to widely differing results and that (iii) the time dependent decrease of liquid water substance and the size of the resulting ice particles were more strongly influenced by the initial ice crystal concentration than by the initial ice crystal size and the habit of the ice particles. By decreasing the number density of ice crystals gradually a critical ice crystal concentration was found at which the present liquid water was not completely consumed by the riming process even after 1800 s model time, causing large drops of radii 〉100 μm to be formed in appreciable concentrations.

Notes: Abstract Helicopter measurements of solar irradiance and meteorological data within the atmospheric boundary-layer were made in Lagos during February 1979. Filter samples of aerosols were collected both during flight in February 1979 and at ground level in December 1978. Profile data on spectral aerosol optical depth were obtained and, from these, the aerosol extinction coefficient at two wavelengths (0.5 and 0.88 μm) were calculated. Precipitable water was low and was contained mainly within the 750 m layer above ground, suggesting the establishment of a deep unstable boundary layer. Calculated channel energy depletions by aerosols show that, within the first 750 m of the surface, the 0·88 μm might be more efficient at attenuating solar energy than 0·5 μm. The lagoon (maritime) aerosol sample indicated a more monodisperse size-distribution than the dusty harmattan aerosol sample.

Notes: Abstract After briefly reviewing the observational data on the stratospheric sulfate aerosol layer, the chemical and physical processes that are likely to fix the properties of the layer are discussed. We present appropriate continuity equations for aerosol particles, and show how to solve the equations on a digital computer. Simulations of the unperturbed aerosol layer by various published models are discussed and the sensitivity of layer characteristics to variations in several aerosol model parameters is studied. We discuss model applications to anthropogenic pollution problems and demonstrate that moderate levels of aerospace activity (supersonic transport and space shuttle operations) will probably have only a negligible effect on global climate. Finally, we evaluate the possible climatic effect of a ten-fold increase in the atmospheric abundance of carbonyl sulfide.

Notes: Abstract Solar radiation of λ〉175 nm and of Lyman-alpha at 121.6 nm is absorbed in the mesosphere and stratosphere by molecular oxygen (λ〈242 nm) and also by ozone molecules at λ〉200 nm. This paper describes the photodissociation processes resulting from absorption in the Schumann-Runge bands and Herzberg continuum of molecular oxygen and also in the Hartley, Huggins and Chappuis bands of ozone. Special consideration is given to differences between the stratospheric and mesospheric problems.

Notes: Abstract The catalytic destruction of stratospheric ozone by the oxides of nitrogen is believed to be an important part of the global ozone balance. The lack of sufficient measurements of NO x concentrations has impeded efforts to quantify this process. Recent measurements of stratospheric nitrogen dioxide from ground-based stations as well as aircraft and balloons have provided a first approximation to a global distribution of NO2 vertical columns at sunset. These observed vertical columns have been translated into time-dependent vertical NO2 profiles by means of a one-dimensional atmospheric photochemical model. Using recent observations of air temperature and ozone along with this information, the independent instantaneous (one second) rates of ozone production from oxygen photolysis P(O3), of ozone destruction from pure oxygen species (Chapman reactions) L(O x ), and of ozone destruction by nitrogen oxides L(NO x ) were estimated over the three-dimensional atmosphere. These quantities are displayed as zonal average contour maps, summed over various latitude zones, summed over various altitude bands, and integrated globally between 15 and 45 km. Although the global summation between 15 and 45 km by no means tells the complete story, these numbers are of some interest, and the relative values are: P(O3), 100; L(O x ), 15; L(NO x ), 45±15. It is to be emphasized that this relative NO x contribution to the integrated ozone balance is not a measure of the sensitivity of ozone to possible perturbations of stratospheric NO x ; recent model results must be examined for current estimates of this sensitivity.

Notes: Abstract An assessment is made of the relative contribution of certain classes of energetic particle precipitation to the chemical composition of the middle atmosphere with emphasis placed on the production of odd nitrogen and odd hydrogen species and their subsequent role in the catalytic removal of ozone. Galactic cosmic radiation is an important source of odd nitrogen in the lower stratosphere but since the peak energy deposition occurs below the region where catalytic removal of O3 is most effective, it is questionable whether this mechanism is important in the overall terrestrial ozone budget. The precipitation of energetic solar protons can periodically produce dramatic enhancement in upper stratospheric NO. The long residence time of NO in this region of the atmosphere, where catalytic interaction with O3 is also most effective, mandates that this mechanism be included in future modelling of the global distribution of O3. Throughout the mesosphere the precipitation of energetic electrons from the outer radiation belt (60°≲Λ≲70°) can sporadically act as a major local source of odd hydrogen and odd nitrogen leading to observable O3 depletion. Future satellite studies should be directed at simultaneously measuring the precipitation flux and the concomitant atmosphere modification, and these results should be employed to develop more sophisticated models of this important coupling.

Notes: Abstract Using standard ‘two-scaling’ techniques we calculate the Eulerian- and Lagrangianmean flows induced at second order in amplitude by small-amplitude, transient, non-dissipative, vertically-propagating inertio-gravity waves on anf-plane. The example is an idealized one, but illustrates a number of important features that are typical of wave, mean-flow interaction in a rotating, stratified fluid. Physical discussion of the solution is given in Section 4 of the review byMcIntyre (1980), which appears elsewhere in this issue.

Notes: Summary This article analyzes the nature of the aerosol information that current or planned spacecraft measurements could contribute toward the required input data for studies of natural anthropogenic influences on the middle atmosphere, and their consequent effects on our weather and climate. The analysis is conducted with particular reference to the solar occultation sounding technique as applied by the SAGE I experiment on the Atmospheric Explorer Mission B spacecraft. Its conclusions should prove to be of use in both the interpretation of the SAGE I data, and in the design of the follow-on mission on the Earth Radiation Budget satellite. Our analysis shows, in particular, that further studies are required in: the choice and number of sounding channels; the data taking sequence in relation to the atmospheric regions probed; the accuracy and vertical resolution of the atmospheric profiling, and their dependence on both the instrument/spacecraft parameters and the data inversion techniques; and the data reduction procedures. Neither of the selected channels is in a one-to-one relationship with an atmospheric constituent; hence, unless further assumptions are introduced, inversion techniques based on such a property are not applicable. The aerosol wavelengths are not satisfactory as they are only sensitive to the large size tail of the aerosol size distribution rather than to the predominant sizes; for these, UV wavelengths would be required. Owing to the change of the Sun's shape due to atmospheric refraction as the Sun either sets or rises, the higher altitudes will be scanned fewer times than the lower altitudes. Also, because transmission approaches rapidly unity above ∼40 km, the same high altitudes are more sensitive to measurement errors-errors that will propagate to lower altitude determinations when inverted profiles are reconstructed from the top of the atmosphere. These two factors, combined with the small air mass values at the high altitudes, are the cause of the mathematical ill-conditioning of the inversion problem. They point toward the need for a data-taking sequence strategy that would trade off between data storage and transmission constraints, larger accuracy at the high altitudes, and proper division of the atmosphere in order to overcome the ill-conditioning. Likewise, and as a result of the above considerations, there is a need for a detailed trade off study between data accuracy and vertical resolution of the reconstructed profiles. This should take into account the seasonal and geographical variations in the distribution of atmospheric constituents, as well as a representative statistical set at any given location and time, appropriate error measures and their vertical profiles, and several inversions utilizing as initial guesses profiles that depart from the true ones. It is also shown that the aerosol and ozone number densities cannot be recovered simultaneously without introducing some formula for the aerosol extincition or assumptions on the form of the aerosol size distribution. This problem is not resolved by the addition of sounding channels because each such channel introduces an additional unknown aerosol extinction. Thus, one is led to a separate rather than a simultaneous determination of the various constituents by resorting to complementary measurements. For a future experiment, it is suggested to determine the ozone separately from measurements at a close pair of appropriate wavelengths between which the aerosol extinction varies slowly whereas that of ozone exhibits a rapid variation. A similar technique could also be used for the separate determination of NO2. The relaxation-type of inversion suggest byChu andMcCormick (1979) does not seem to be appropriate because each channel is not sensitive selectively to an individual constituent, the aerosol channels are not sensitive to the important sizes in the distribution, and the sensitivity of the channels to the constituents of interest varies greatly with altitude. In the retrieval of the vertical profiles, the cause of the ill-conditioning of the inversion is identified. Two approaches are suggested for overconing this problem: (i) build the profile starting from the top of the atmosphere (forward procedure) but with an initial layer of sufficient air mass, or preferably (ii) reconstruct the profile from the lowest altitude reached (backward procedure) with a renormalization at the top of the atmosphere. In this process, the minimization search method (Fymat, 1976) would appear to be a better technique than the onion-peeling technique, as demonstrated byMill andDrayson (1978). In order to maximize the scientific return of SAGE I, a data inversion procedure is proposed. It assumes that (i) there are no aerosols above ∼25 km, and no NO2 below this altitude (as suggested byChu andMcCormick, 1979), (ii) below ∼25 km, ozone (and NO2, if present) could be determined separately, and (iii) the aerosol has a known refractive index at all wavelengths of interest, is assumed to be spherical (or describable in terms of ‘equivalent spheres’), and the minimum and maximum radii of its size distribution are known a priori. Under these assumptions, it is possible to retrieve the neutral density, NO2 and O3 profiles above ∼25 km, by either the forward or the backward procedure described above. Taking into consideration the power law variation of the air density with altitude, it is further possible to reconstruct the corresponding profiles at all the lower altitudes from the determinations in the altitude range ∼30–40 km. Below ∼25 km, the four SAGE I channels would then all become available for the aerosol inversion. While the profile reconstruction could proceed as for the higher altitudes, the aerosol inversion at each individual altitude presents problems of its own. Results of numerical experiments for aerosol inversion using all four SAGE wavelengths and seven different inversion routines are presented. If good a priori information is available on the sought size distribution solution, reasonably satisfactory inversions can be performed (see line 1 of Table 2, and Fig. 3c and 3d). However, in the absence of such information, there are as many solutions as inversion methods tried, in complete conformity with the well-known ill-conditioning of the problem. Among methods providing physically meaningful solutions, no method could be singled out as preferable to the others. In these inversions, the data were assumed to be exact, and 99% of the distribution were used. Under different conditions, the nonuniqueness of the inversion would be further compounded. Lastly, based on the present study, a strategy is suggested for the design and data interpretation of a follow-on SAGE-type experiment. Considering the important advantages to this problem presented by forward scattering, as demonstrated byFymat andMease (1978), a composite (extinction-forward scattering) experiment is recommended for the future experiments.

Notes: Abstract Solar radiance measurements covering over seventeen months are analysed for a location beside the Lagos Lagoon. The aerosol extinction coefficient was generally higher in the dusty months than in the wet months. ‘Clean air’ estimates of the coefficient are made. Data on its wavelength dependence are also presented.

Notes: Abstract Phase velocities of Rayleigh waves for the Adriatic Sea area are obtained in the period range 25–190 sec along the path (l'Aquila-Trieste) AQU-TRI and 20–167 sec along the path (Trieste-Bari) TRI-BAI. The phase velocities are systematically higher than the known values for the surrounding regions. The data inversion indicates the presence of a lithosphere typical of stable continental areas with clear high-velocity lid (V s ∼4.6 km/sec) overlying a well developed low velocity zone (V s ∼4.2 km/sec).

Notes: Abstract Model uncertainty is introduced into direct-current resistivity data by adding random changes to layer thicknesses in a ten-layer model. The resulting information is then aliased by generating a sounding curve which contains less information than the ten resistivities and nine thicknesses. These sounding curves are then inverted via the Backus-Gilbert algorithm using singular value decomposition to obtain solutions in terms of simpler two-or three-layer models. Quantitative results confirm what has been known qualitatively for many years as the principle of equivalence. An interesting result is that the geometric average of a given suite of noisy models is virtually identical to the best-fit model for the average of the noisy curves. The results show that the inversion of resistivity data by nonlinear least-squares parameter fitting is stable in the sense that noise in the data inverts to the same magnitude of noise in the model.

Notes: Abstract Results are presented from a two-dimensional, time-dependent model of the atmosphere which has been used to investigate perturbations to the ozone layer due to chlorofluorocarbons. The unperturbed stratosphere is modelled well with the observed features of the ozone distribution reproduced. The main features of the perturbation calculations are the large latitudinal and seasonal variations found in the modelled ozone reductions with greates reductions where the total ozone amounts are largest. The importance of at least a two-dimensional study in problems of this kind is stressed and the important role of dynamical and radiative processes, as well as chemical, is indicated.

Notes: Abstract For a thermal starting from rest, the scales of motion consistent with the initial conditions are given. An alternative time scale based on the motion of the thermal is derived. The anticipated similarity solutions for thermals are summarised and possible qualitative differences between solutions are given. Within this consistent framework previously published laboratory and numerical models of thermals are discussed. Reasons why numerical models have not rigorously demonstrated the existence of a self-similarity solution are considered. Comparisons of all available results show that a single similarity solution valid for all thermals does not exist.

Notes: Abstract The measurement of the atmospheric electric field was carried out with a field mill at a small island in a bay on the Pacific coast of Japan. The data obtained during 80 months from 1971 to 1977 were analysed. It was found that characteristically the diurnal variation regularly alters with the seasons. Whereas the electric field in winter has the same diurnal pattern as that observed at globally representative stations, it exhibits in summer a pattern depending on the variation of the local electric conductivity. The alteration is inferred to be associated with regional atmospheric conditions surrounding the observation site.

Notes: Abstract This paper examines the evidence for the model of a small cumulus cloud represented as a quasi static but turbulent entity, growing on the upshear side and decaying on the downshear side. While the air just outside the cloudy outline is, on average, stationary relative to the embedding airmass, there is a slight flow, upwards and forward as though the updraft has induced upward motion in the clear air outside the cloud, on the growing side. On the decaying side the motion is downwards and away from the cloud. This is a flow pattern which is not consistent with the air flowing around the cloud as it moves forward but it agrees well with the picture given. Decayed remnants of cloud are found throughout the air previously occupied by the cloud. The cloud outline moves through the embedding air at a velocity which is almost as large as the relative motion of the subcloud feeding airflow (which is almost free from internal wind shear in strong convection). The mixing of dry air from above the inversion yields the observed diluted liquid water content in small cumuli, if such mixing is allowed to proceed until the cloud density equals that of the surrounding air. Quantitative conditions relating the liquid water to inversion temperature and moisture changes, and to the stability of the environment are presented. The strong vertical mixing from the top of the cloud downwards is important to microphysical processes.

Notes: Zusammenfassung Die Anfangsadjustierung der atmosphärischen Zustandsvariablen und die sehr kleinen Rechenzeitschritte sind Kernprobleme der numerischen Simulation von grossräumigen Wetterentwicklungen auf der Basis strenger hydrodynamischer Vorhersagemodelle. In dem vorliegenden Aufsatz wird ausführlich diskutiert wie beide Prognosehindernisse mit geeigneten Verträglichkeitsbedingungen (diagnostische Differentialgleichungen) zwischen den atmosphärischen Feldgrössengemeinsam beseitigt werden. Diese Bedingungsgleichungen sind gleichzeitig verwendbar, um (1) die Anfangsfelder der meteorologischen Variablen so aneinander anzupassen, dass kurzperiodische Lärmeffekte weitgehend unterdrückt werden (ungefilterte Systeme) (2) originäre Modellgleichungen zu ersetzen, so dass die meteorologisch irrelevanten Lärmwellen (mit lästig kleinen Zeitschritten) in den mathematischen Lösungen eliminiert werden (gefilterte Systeme). Die konsequente Nutzung der Lärmfiltertechnik führt (bei einem vertretbaren mathematischen Aufwand) in der Praxis dazu, dass während des numerischen Lösungsprozesses Lärmwellenanteile bis zur Unwirksamkeit reduziert und meteorologisch relevante Rossby-Wellen hinreichend gut konserviert werden. Die Praktizierbarkeit der Lärmfiltertheorie wird an einem (barotropen) 1-Schichtenprognosemodell rechnerisch realisiert und veranschaulicht. Die Kernprobleme der Initialisierung und der Lärmfilterung (Zeitschritt) werden dabei separat diskutiert.

Notes: Abstract Atmospheric mercury concentrations were measured during a nautical expedition on the Atlantic Ocean between Hamburg (54°N, 10°E) and Santo Domingo (20°N, 67°W). In addition, samples were taken during flights on a commerical aircraft in the upper and middle troposphere between 60°N and 55°S, mostly over the Pacific Ocean. The data obtained in the lower troposphere over the Northern Atlantic show considerable variation in the Hg concentrations, with values ranging between 1 and 11 ng/m3; the average concentration was found to be 2.8 ng/m3. The upper tropospheric data show an interhemispheric difference with average values of 1.45 ng/m3 and 1.08 ng/m3 in the Northern and Southern Hemisphere, respectively. This suggests that mercury production occurs predominantly over the continents both by natural and anthropogenic processes. The mercury content in aerosols was found to be ≤0.3 ng/m3, or one-tenth of the atmospheric concentration. The data indicate a mean residence time of mercury in the atmosphere of a few months to one year.

Notes: Abstract Compressional and shear-wave velocities (V p andV s ) were measured during the generalized triaxial deformation (i.e.σ 1≠σ 2=2σ 3) of pyrophyllite. Observed velocity changes could be ascribed to crack development during dilatancy. Velocity changes were very localized with respect to the ultimate failure plane. The orientation and development of the failure plane was continuously observed with laser holography. Velocity reverals, i.e. changes from a decreasing trend to an increasing trend, were documented in a wet sample in bothV p andV s . These changes in bothV p andV p are inconsistent with dialatancy-diffusion models. The reversals were interpreted as a reflection of local stress reorientation caused by a slowly propagating fault.

Notes: Abstract Meteorological rocket soundings, launched between 1968–74 at six locations representative of low, middle, and high latitudes in the northern hemisphere, are employed to determine the vertical, meridional and off-diagonal components of the eddy diffusivity in the northern hemispheric statosphere and lower mesosphere. It is shown that the distribution of the vertical and meridional components of the eddy diffusivity are similar in the northern hemisphere, although the magnitude of the former is 107 smaller than that of the latter; the magnitude of the off-diagonal eddy diffusivity is about 103 smaller than that of the meridional eddy diffusivity. In the troposphere, a maximum eddy diffusivity occurs in the mid-latitude at about 7 km above the mean sea level for both the summer and winter seasons. In the stratosphere, a maximum eddy diffusivity occurs in the mid-latitude at about 33 km in the winter, but no maximum in the summer.

Notes: Abstract The results of numerical models or of new observational programs are checked by comparing them with past observations. Also, it is desirable that the eddy diffusion coefficients used in two-dimensional models be derived from the same data set as the circulation statistics which the model outputs are checked against, so that all results refer to the same atmospheric conditions. For the first time, the three components of the eddy diffusion matrix, from 30–60 km, 80°N–10°S are computed, together with the means, variances and covariances of the wind and temperature through the same region using the same data set for 1960–76 and the same handling and analysis methods for all variables. Horizontal diffusivities,K yy , are obtained from the variance and integral time scale of the meridional wind speed. The present values are generally smaller than past estimates, presumably because temporal variations longer than a month have been removed in this work. Estimates ofK yz are based on the tentative assumption that the diffusivity is proportional to the slope of isentropic surfaces, and estimates ofK zz are based on the assumption that small-scale gravity waves are primarily responsible for vertical mixing.

Notes: Abstract Computations of concentrations of minor stratospheric gases using a two-dimensional model of the stratosphere are reported. The model includes Rayleigh scattering. This results in an increase in the photodissociation rate computation time by a factor of 1.5. The effect of ground albedo is assessed by comparing our results with a calculation of photolysis rates for a constant albedo with latitude. Comparison of results with a reference model including only molecular absorption are also made. The largest differences (≲50%) occur in NO and OH. An approximate expression for including the effects of Rayleigh scattering and surface reflectance in multi-dimensional models is suggested.

Notes: Abstract It is shown how to retrieve the atmospheric ozone profile by means of ground based microwave measurements of the radiative intensity. Chahine's iteration method is used. The method is tested by a numerical experiment. The retrieval rms about the mean error is approximately 0.4 ppm. The required measurement accuracy for the brightness temperatures is ±0.01 K.

Notes: Abstract Values for mean precipitable water are computed for four seasons of the year and for different regions of the Southern Hemisphere. Relationships between surface dew-point temperature and precipitable water were studied for these regions. A harmonic analysis of our data on precipitable water is attempted. Out results are presented and discussed.

Notes: Abstract The paper defines the intertropical convergence zone. (ITCZ) in the Indian monsoon region during the northern summer, identifies it with the northern boundary of the advancing monsoon and suggests that its seasonal movement can serve as an indicator of onset, advance and withdrawal of the monsoon. Evidence suggesting the movement of the ITCZ which is associated with the equatorial trough of low pressure is indirectly furnished by an analysis of the isallobaric or height-tendency field which reveals a distinct gradient towards the north/south during period of advance/withdrawal of the monsoon. A comparative study of the dates of onset of monsoon during two successive years appears to suggest that some of the problems encountered in using rainfall as the sole criterion for determining the onset and advance of the monsoon may be over-come by using the ITCZ concept as proposed in the present paper. Attention is drawn to the effects of synoptic-scale disturbances on the normal dates of onset, advance and withdrawal of the monsoon.

Notes: Abstract A theoretical model is presented which allows computing the efficiency with which aerosol particles of 0.001 ≤r≤1 μm are collected by columnar ice crystals in air of various relative humidities, temperatures, and pressures. Particle capture due to Brownian diffusion, thermo- and diffusiophoresis is considered. It is shown that phoretic effects importantly determine the particle capture process of 0.01≤r≤1 μm. The various pressure-temperature levels studied are found to affect the collection efficiency only ifr〉0.1 μm. Comparison shows that water drops generally are better aerosol particle scavengers than columnar ice crystals.

Notes: Abstract A theoretical model is presented which allows computing the efficiency with which aerosol particles of radius 0.1≤r≤10 μm are collected by simple ice crystal plates of radius 50≤a c ≤640 μm in air of various relative humidities, temperatures and pressures. Particle capture due to thermophoresis, diffusiophoresis and inertial impaction are considered. It is shown that the capture efficiency of an ice crystal in considerably affected by phoretic effects in the range 0.1≤r≤1 μm. For aerosol particles ofr〉1 μm the efficiency is strongly controlled by the flow field around the crystal and the density of the aerosol material. Trajectory analysis also predicts that aerosol particles are preferentially captured by the ice crystal rim. Our theoretica results are found to agree satisfactorily with the laboratory studies presently available. Comparison shows that for the same pressure, temperature and relative humidity of the ambient air ice crystal plates are better aerosol particle scavengers than water drops.

Notes: Abstract The paper deals with the atmospheric gaseous nitrogen-compounds under special consideration of the ocean being a source for NH3. The distribution of NH3 and NH4 + in the ocean is discussed. Additionally a survey of measured marine pH-values is given. While in temperate latitudes the source-strength of the ocean seems to be low, no such statement can be made at present for tropical latitudes owing to lack of measurements.

Notes: Abstract A Fourier transformation of the magnetic field from a magnetized sphere allows a particularly simple interpretation of the parameters of the sphere. The depth to the centre and total magnetic moments of the sphere are related to the intercept and slope of the power spectrum. The horizontal centre and direction of magnetization are related to slope and intercept of the phase spectra in two perpendicular, horizontal directions. Examples with artificial data contaminated by various noise components are presented.

Notes: Abstract Ion exchange and flameless atomic absorption spectrophotometry methods were used to measure the concentrations of sodium, manganese, iron and silver in snow accumulating at several sites on the Antarctic continent. The results show that the ratio of Mn/Fe is consistently close to the crustal value at all sites. The silver concentrations observed suggest a different origin, probably oceanic. When referenced to sodium, the degrees of enrichment of silver, manganese and iron increase by factors of 8, 2 and 2 respectively over a distance of 500 km from the ocean, after changes in sodium are accounted for. Investigation of the heavy metal content of fresh falling precipitation occorring on the Ross Ice Shelf, has shown that more enhanced enrichments of silver, manganese and iron occur in this fresh precipitation by factors up to 100, than in samples of snow and firn collected from shallow (up to 2 meters depth) pits at the same locations. Because the occurrences of these precipitation types vary temporally and geographically, it seems apparent that the shear stress conditions in the near surface boundary layer need to be considered in studies of snow and ice chemistry, particularly in polar regions where the chemical composition of permanent snow and ice fields are often investigated for evidence of climatic change, of glaciological behavior and of origins of chemical constituents.

Notes: Abstract Rayleigh's principle and the concept of the local wave number have been utilised for the approximate determination of the dispersion of Love waves propagating in a laterally heterogeneous layer lying over a homogeneous half-space. The shear wave velocity and the rigidity in the surface layer have been assumed to decrease with the increase of the lateral distance from the origin. The range of validity of the dispersion equation obtained by this method has been examined critically. It was found that: (a) for existence of Love waves the minimum value of shear wave velocity in the layer must be less than that in the matter below, and (b) the phase velocity of Love waves decreases with the increase of the lateral distance from the origin.

Notes: Abstract TheP-arrival times of local and regional earthquakes that are outside of a small network of seismometers can be used to interpret crustal parameters beneath the network by employing the time-term technique. Even when the estimate of the refractor velocity is poorly determined, useful estimates of the station time-terms can be made. The method is applied to a 20 km diameter network of eight seismic stations which was operated near Castaic, California, during the winter of 1972–73. The stations were located in sedimentary basins. Beneath the network, the sedimentary rocks of the basins are known to range from 1 to more than 4 km in thickness. Relative time-terms are estimated fromP-waves assumed to be propagated by a refractor in the mid-crust, and again fromP-waves propagated by a refractor in the upper basement. For the range of velocities reported by others, the two sets of time-terms are very similar. They suggest that both refractors dip to the southwest, and the geology also indicates that the basement dips in this direction. In addition, theP-wave velocity estimated for the refractor of mid-crustal depths, roughly 6.7 km/sec, agrees with values reported by others. Thus, even in this region of complicated geologic structure, the method appears to give realistic results.

Notes: Abstract It is shown, through numerical experiments, that the effect of ignoring ellipticity and rotation of the earth when inverting free oscillation data in moment tensor studies, is to introduce spurious spectral components in the solution. For numerical simulation of the data conditions of the 1970 deep Colombian event the spurious part has isotropic and deviatoric components, besides a distortion in the phase spectra which may lead to artificial precursive source in the solution. The magnitude of the artificial isotropic component is of the order of 10% of the real source moment tensor, depending on the data set used in the inversion. Measuring the excitation of each mode at each station using the technique of integrating over the spectral peaks does not cancel completely the effect of multiplet splitting, in particular that splitting due to rotation of the earth. The effect of lateral heterogeneities was simulated by introducing arbitrary splitting parameters which produced scattering in the eigenperiods compatible with those observed. For that splitting the inversion rendered additional isotropic components. We conclude that the observed implosive precursor the the 1970 Colombian event could have been artificially introduced by ignoring rotation, ellipticity and lateral heterogeneities of the earth. A procedure to invert free oscillation data for an elliptical rotating earth is proposed. It could be applied to a laterally inhomogeneous earth if the excitation for that model could be computed. Its application to real data for the deep Colombian event indicates that we will need to improve our knowledge on the effect of rotation, ellipticity, lateral heterogeneities and anelasticity on free oscillation and their excitation in order to solve accurately for the six components of the moment tensor independently.

Notes: Abstract The precision of measurement of surface-wave phase velocities at very long periods has reached a point where the exact, rather than asymptotic, form of the spherical harmonics must be considered in order to compute theoretical phase velocities or phase delays. The zeroth-order (i.e. constant) polar phase shift afterBrune et al. (1961) applies only between stations antipodal to each other. Everywhere else a correction for incomplete polar phase shift must be applied even if the waves do not cross a pole between the stations. The correction can exceed one percent of the total phase delay and thus be of the same order as the expected regional anomalies. It depends on the epicentral distance on the signal period and on the focal mechanism; the latter dependence can make the practical application cumbersome. We derive first-order asymptotic formulae for the correction of local phase velocities and total phase travel times of Rayleigh waves.

Notes: Abstract Long-period recordings of dispersive Rayleigh waves along numerous station lines, or ‘profiles’, in Europe have for the first time permitted a uniform inversion of these observations based on a new method of phase velocity regionalization. Regional dispersion relations obtained by this method have then been subjected to a complete inversion procedure commonly known as the ‘hedgehog’ method. The results are presented in a map outlining the thickness of the lower lithosphere (‘lid’) and the shear (S) velocities in both the ‘lid’ and the asthenosphere ‘channel’. A comparison of these results with the minimum compressional (P) wave velocities in the asthenosphere and their corresponding depths provides an estimate of theV p /V s ratio for the asthenosphere in the European area.

Notes: Summary To derive the structure of the Lower Mantle, observations of P and S waves at epicentral distances beyond 90 degrees have been used. The arrival times and amplitude decay with distance proved to be a source of information to derive the structure near the core-mantle interface. These observations were compared with results of theoretical calculations based on full wave theory [1, 2, 5, 6]. Another important theoretical method is the reflectivity method [4]. Differences between the two methods have a direct bearing on the interpretation of the observations and therefore need to be investigated. In the two methods the wave propagation involved in diffraction is simulated in different ways. In this paper the importance of approximations involved in each of the methods will be discussed. For this purpose the calculation of the frequency-dependent decay with distance of diffracted SH waves has been chosen. The approximations are considered to be important both in P and SH diffraction. The advantage of studying SH waves is the simpler and more straightforward formulation.

Notes: Summary The SH body-wave spectrum of a deep earthquake, which occurred at the foot of the Kamchatka peninsula and was recorded in the Solomon Islands, presents a regular modulation. The distribution of minima in the amplitude spectrum, corresponding to jumps in the phase spectrum, conforms with that expected from the interference between direct and surface reflected waves. The strong dependence of the modulation on the focal depth, emerging from theoretical SH body wave spectra obtained with the contribution of the first 21 higher Love-wave modes, was used to investigate the focal depth of the event here considered. The value estimated, 140 km, agrees with an earlier focal depth determination by travel time data.

Notes: Abstract Shallow strike slip earthquakes on vertical faults are modelled as two-dimensional antiplane strain ruptures in a uniformly prestressed homogeneous halfspace. Behind the rupture front, which is specified, the stress drops to a lower value. The elastodynamic boundary value problem is solved with a finite difference method. Several cases are studied, which include symmetric and one-directional rupture propagation, surface faulting, multiple events, variable rupture velocity, sticking and rebreaking of the fault plane. The time function of displacement, velocity and acceleration are interpreted as signals generated by events in the focus, namely starting, stopping and breaking through the surface of the rupture. The model explains peak velocity and peak acceleration in the near field of M≈5.5–6 earthquakes; which are typically about 0.2 m/s and 5 m/s2 at 10 km epicentral distance, if the rupture velocity is close to the shear wave velocity. Sticking of the fault does not alter the accelerograms significantly, but it increases the seismic moment in simple events and decreases it in multiple events.

Notes: Abstract The paper discusses basic ideas and principles underlying methods, which have proved useful in the interpretation of diffraction and scattering phenomena by a smooth or slightly rough solid-liquid interface. Generally, the wave interaction may be formulated as an excitation problem; it involves (1) finding an equivalent dislocation or source distribution on the interface, and (2) evaluating the excited wave field. These steps are taken through perturbation theory and/or adopting the appropriate generalization of ray theory. In this context an explicit form of Green's function is also given. The methods have been applied to the core-mantle boundary, with a view toward the interpretation of recent data: (a) diffracted P and S waves around the core (in particular, their attenuation); (b) scattered short-period core phases (in particular, precursors to PKP and PKKP). Other types of wave interaction, and implications for models of the core-mantle boundary structure, are briefly mentioned.

Notes: Abstract The derivation of P and S velocities at the core-mantle boundary (CMB) from long-period diffracted waves by the use of the simple ray-theoretical formulav CMB=r c /p (v CMB=velocity at the CMB;r c =core radius;p=ray parameter) yields apparent velocity values which differ from the true velocities. Using a dominant period of about 20 sec for calculating theoretical seismograms, we found a linear relation between the apparent velocity and the average velocity in a transition zone at the base of the mantle with fixed velocity on top. The ray parameters determined from long-period earthquake data are found to be 4.540±0.035 and 8.427±0.072 sec/deg for Pdiff and Sdiff, respectively. These values yield apparent velocities of 13.378±0.103 for P and 7.207±0.062 km/sec for S waves. By means of the theoretical relation between apparent and average velocity and under the assumption of linear variation of velocity with depth, one can invert the apparent velocities into true CMB velocities of 13.736±0.170 and 7.320±0.124 km/sec. These results imply positive velocity gradients at the base of the mantle and hence no significant departures from adiabaticity and homogeneity.

Notes: Abstract Data from a reversed seismic crustal profile crossing the Caledonides of southern Norway suggest a continuously increasing P-wave velocity followed by a low-velocity zone extending from a depth of about 14 km downwards. Interpretation of observed travel time and amplitude characteristics leads to a thickness of 4 km and velocity of 6.0 km/s for this layer, the velocity above and below it being about 6.6 km/s. The role of such a velocity inversion is discussed in the tectonic framework of the Caledonian orogeny and other relevant geophysical information, and it is suggested that the low-velocity zone materializes deep-seated sediments under Precambrian crystalline rocks. The structure of the lower crust is more tentatively established, but still in reasonable agreement with other seismic investigations in the general profiling area.

Notes: Abstract A scheme of a system of physical and chemical processes controlling the production, transport and destruction of ozone and its gaseous catalysts, as well as other related gases in the low and high stratosphere is presented. An account is made of temperature variations of the stratospheric layer resulting from changes in ozone content; also included is the effect of temperature variations on photochemical reaction rates and ozone and other gases transport between atmospheric layers. Parameters describing major relations of the system are inferred from the analysis of ozone and trace gas data and from the results of model calculations of interdependence between variations in temperature and ozone content of the layer. An analysis of minor fluctuations of the linearized system shows that photochemical processes are responsible for its aperiodic stability and that gas transport between atmospheric layers destabilizes the system.

Notes: Abstract The effect of the time change of static stability and wind shear on a two-level quasigeostrophic baroclinic wave is considered. First, by keeping the wind shear as a constant the effect of the increase of static stability is that the amplitude of the temperature wave reaches a maximum first while that of the stream field is still amplifying and, as that of temperature wave reaches a minimum, that of the stream field becomes a maximum, and both are in phase. Next, by keeping the static stability as a constant, a life cycle of disturbance associated with the time change of wind shear is obtained. In this case the maximum amplitude of the wave appears at about 6 days and the life cycle is about 11 days for reasonable values of the model parameters. Finally, both effects are considered. The results show that as the wind shear decreases, the static stability increases, and the percentage change of wind shear is larger than that of static stability. This paper is not an entirely convincing analysis of the finite amplitude dynamics of an unstable wave in the two-level model, but rather a pedagogically useful approximate theory in which the retention of some terms rather than others is justified in view of the plausibility of the results.

Notes: Abstract This paper examines the effects of the mixing of dry air into a cloud top from the point of view of the droplet spectra. It is shown theoretically that the resulting cycling of the air up and down in the cloud, as seems to be the essential mechanism by which cumuli have been diluted to their observed liquid water mixing ratio, can double the largest drop radius and generate cloud parcels containing drops of all sizes up to this maximum. These changes in the droplet distribution with size occur by a process which is not greatly influenced by the cloud condensation nuclei or the details of droplet growth since ‘maritime’ like spectra can develop in ‘continental’ type cumuli. It shows that large numbers of cloud condensation nuclei should not have much effect in inhibiting the rainforming process by reducing coalescence growth. On the contrary, the controlling parameters which determine precipitation efficiency and times seem to be those which control the mixing.

Notes: Schlußfolgerungen 1. Auch bei den Seeigeleiern wirkt die Schwerkraft mit bei der Bestimmung der Richtung der ersten Furchungsspindel. 2. Wider Erwarten nimmt die Spindel die wagerechte Richtung unter der Wirkung der Schwerkraft nicht an, sie ordnet sich hingegen um 45° gegen den Horizont an. 3. Wie die Versuche erweisen, ist die stabile Gleichgewichtslage zweier an Volumen und Gewicht einander gleichen beweglichen Kügelchen innerhalb einer Kugel, wenn die Summe ihrer Durchmesser dem Durchmesser der Kugel gleichkommt, gerade diejenige Lage, in welcher die beiden Kügelchen ihre Mittelpunkte auf einer um 45° gegen den Horizont geneigten Geraden haben, wie man es genau bei den Eiern der Seeigel beobachtet. 4. Diese Tatsache ist ein neuer untrüglicher Beweis dafür, daß die Karyokinesis wirklich in der schrittweisen Bildung und ebensolchem Wachstume zweier Kügelchen im Inneren der Mutterzelle besteht, welche bestimmt sind, die künftigen Tochterzellen zu werden. 5. Keine andere Erklärung der Karyokinesis kann uns bis jetzt Aufschluß darüber geben, daß und warum die erste Furchungsspindel sich unter der Einwirkung der Schwerkraft so verhält. 6. Die besagte Neigung der ersten Furchungsspindel erlaubt uns schließlich, zu erklären, wie die inäquale Furchung bei vielen Eiern von der ersten Teilung an ermöglicht wird, wofür sich keine Erklärung finden würde, wenn die erste Spindel horizontal wäre. 7. Die schräge Neigung der Spindel und die Ungleichheit der Furchung sind zwei Erscheinungen, welche eine auf die andere einwirken. Die von der Schwerkraft erzeugte Neigung ruft die Ungleichheit der Teilung hervor, und diese vergrößert die Neigung der Spindel. Die Schwerkraft ist also die erste Ursache dieser Tatsachen. 8. In der ungleichen Teilung wird die Spindel unter der Wirkung der Schwerkraft, je größer der Unterschied zwischen dem Volumen und dem Gewichte der beiden Blastomeren ist, desto mehr das Bestreben haben, sich der vertikalen Richtung anzunähern, ohne sie jedoch jemals zu erreichen. Die Mikromere entsteht also um so mehr in der Nähe des oberen Eipoles je kleiner sie in bezug auf die Makromere ist.

Notes: Summary Antisera against larval and adultXenopus hemoglobins as well as adult human hemoglobin showed no cross-reaction when tested by immunodiffusion against each heterologous antigen. In this test hemoglobin of a single animal produced two precipitation lines for larvae, but only one for adult stages. Immunoelectrophoresis also revealed more complex precipitation patterns for larval than for adult hemoglobins. Hemoglobin of the isogenic hybrid cloneXenopus laevis/X. gilli also reacted with antisera against normalXenopus hemoglobin. Quantitation of hemoglobins, analyzed by radial immunodiffusion showed fewer than 1% of adult hemoglobin in red cells of larvae, but 30% at completion of metamorphosis. Two weeks later adult hemoglobin attained over 90%, and in red cells of adultXenopus an average of 1% larval hemoglobin were detected. The relatively short transition period suggests that the loss of larval hemoglobin may be due to the elimination of larval red cells, and that the increase in adult hemoglobin may be indicative of a new cell line.

Notes: Summary Drosophila melanogaster chorion proteins are characterized on one-dimensional isoelectric focusing (IF) gels. The six major chorion components previously identified on SDS gels are shown to resolve into at least 11 components in our IF system. IF screening of 102 geographic strains ofDrosophila melanogaster revealed seven cases of variation in major chorion components. Two strains, Crimea and Falsterbo, which were monomorphic for a variant B1 protein and two strains, Skafto and Lausanne, which were monomorphic for a variant C1 protein, were chosen for further study. After IF developmental analysis of F1 hybrids had indicated that the sources of the variation resided in the structural genes for these proteins, each variant was crossed to a multiply marked and inverted strain (BLT) to determine the linkage group of the variant gene. To localize genes to more specific sites multiply marked 3rd (SKERO) or X-chromosomal (CB1) (X-PLE) mapping strains were used. In both Crimea and Falsterbo the gene for the B1 protein is located near map location 26 on the 3rd chromosome. In both Lausanne and Skafto the C1 gene is located on the X chromosome. Hence, for the first time, we have demonstrated genetically the non-linkage of two chorion genes, B1 and C1.

Notes: Summary The effects of nitrogen mustard (methylbis-chlorethylamine) on limb organogenesis were studied inPleurodeles waltlii at different stages of fore and hind limb development. The effects of four different doses of nitrogen mustard (1.25; 2.5; 5 and 10 μg/ml) on the limb bud mesoderm and epidermis were studied histologically. This analysis was carried out on cylindrical unchondrified hind limb buds treated at stage 45. The effects of these doses on all stages of fore and hind limb development were investigated. This included the effect on the establishment of the proximo-distal sequence (segment chondrification) and the antero-posterior sequence (pre-postaxial zeugopod, basipod chondrification and progressive pre-postaxial organization of fingers and toes. Correlations were established between the mesodermal necrosis observed in hind limb buds treated at stage 45 and the skeletal abnormalities occurring in fore and hind limbs after treatment at all stages of their development. Thus, it appears that the effects of nitrogen mustard on organogenesis demonstrates the existence of a state in the differentiation of the mesoderm that is not revealed by morphological studies.

Notes: Summary The inducing activity of the vegetalizing factor decreases after covalent coupling to CNBr-Sepharose with reduced binding capacity. The residual inducing activity is probably due to the release of a small amount of the factor from Sepharose beads. Covalent coupling to activated CH-Sepharose completely inactivated the vegetalizing factor, whereas the neuralizing factor retained its full activity. The biological activity was also very much reduced when the vegetalizing factor was bound to Sephadex beads, a derivative of dextran. Fully active factor was recovered after enzymatic degradation of the dextran matrix with dextranase. The experiments suggest that the neuralizing factor acts on the cell surface of ectoderm cells, whereas the vegetalizing factor must probably be internalized to become biologically active.

Notes: Summary The larva ofIschnochiton gradually develops 6 transversal ridges and later a seventh one on its back. These intersegmental ridges are composed of two types of cells, one of them a goblet cell, as they are found in the girdle. Both types of cell seem to be responsible for cuticle secretion. The depressions between the ridges, called plate fields, are responsible for plate secretion. There are two different cell types. The marginal ones, which remain slender and tall, develop an enormous flat villus (here called a stragulum). Each plate field is tightly sealed against sea water by the stragulum. In the crystallization chamber formed by the stragulum, the first plate anlage is formed. In the later stages, the stragulum protects the growing plate margin. No periostracum is found. Most probably the cells developing the stragulum are responsible for the secretion of the tegmentum and in early development are the only secretory cells. The central cells of the plate field, which very soon flatten, then produce the second plate layer, the hypostracum. There is no secretion product in common to plate fields and intersegmental ridges. During the developmental period studied inIschnochiton (from hatching to 94 h) the number of cells of the individual plate field is not increased. The earliest anlage of the plates inMiddendorffia andIschnochiton is rodlike with straight margins and is not composed of several granules. Growth takes place at least inMiddendorffia by apposition of lime to the ends, posterior and, preferably, anterior margins. All plates are posttrochal.

Notes: Summary Concentrations of the cyclic nucleotides in regenerating limb tissues change in a manner which suggests that they might mediate neural or endocrine influences upon specific developmental events. Since modulation of the role of cAMP within this process can be achieved through cAMP phosphodiesterase, enzymatic activity, relative intracellular distribution, and the kinetic parameters of this enzyme were examined at several stages of limb regeneration in adultNotophthalmus viridescens. Both forms of the phosphodiesterase displayed decreased activity about the time of bud formation. Total phosphodiesterase activity was reduced between 66% and 85% (as compared to intact limbs) between wound healing and palette stages. Relative intracellular distribution (soluble vs. particulate), however, remained essentially constant, 93%–98% soluble for the highK m form and 61%–71% soluble for the lowK m form of the enzyme, throughout this process. The apparentK m of the highK m form increased more than 2-fold during wound healing then fell to approximately 10% (0.7–1.1 μM) of the value of intact limbs (8.3 μM) during dedifferentiation and bud formation. A return to pre-amputational levels was subsequently achieved. In contrast, the apparentK m of the lowK m form increased (from 0.064 to 0.86 μM) during dedifferentiation and began decreasing thereafter. These results are consistent with the hypothesis that one or more mechanisms are operating to modify either the quantity, activity, or physical characteristics of the cAMP phosphodiesterases and that such changes are instrumental in regulating endogenous concentrations of cAMP in limb tissues during regeneration.

Notes: Summary Methods are described for isolation and culture of primary mesenchyme cells from echinoid embryos. Ninety-five percentpure primary mesenchyme cells were isolated from early gastrulae ofStrongylocentrotus purpuratus, exploiting the biological segregation of these cells within the blastocoel. When cultured, more than 90% of the isolated cells reached the differentiated state, spicule formation, in synchrony with in vivo controls. Isolated primary mesenchyme cells were cultured with and without various cellular and acellular components of normal embryos in order to study the potential involvement of these components in the morphogenesis of the primary mesenchyme. Our data indicate that: 1. primary mesenchyme cells lack the ability to form the annular pattern of the primary mesenchymal ring autonomously; 2. they autonomously produce spicules of a characteristic morphology that differs from that of embryonic spicules; 3. morphogenesis of the primary mesenchyme is not affected by association with embryonic basal lamina, blastocoel matrix, or loosely aggregated epithelial cells, or by close confinement of each set of primary mesenchyme cells within the blastocoelar space; and 4. reaggregated, tightly associated epithelial cells can promote normal primary mesenchyme ring formation, and modify the primary mesenchyme-intrinsic spicule pattern to produce more normal spicule forms.

Notes: Summary The migratory and organogenetic capacities of muscle cells at different stages of differentiation were tested in heterospecific chick/quail recombinants. Grafts containing muscle cells were taken from the premuscular masses from 4- to 5-day quail embryos, from the limb or trunk muscles of 12-day embryonic and 4-day post-natal quails, and from experimentally produced bispecific premuscular masses in which the myoblasts are of quail origin and the connective tissue cells of chick origin. Grafts were implanted into 2-day chick embryos in place of the somitic mesoderm at the limb level. Hosts were examined 4 to 7 days after operation. After implantation of a piece of premuscular mass, quail cells were found at and around the site of the graft in the truncal region and within the limb as far as the autopod. Quail cells participated predominantly in the trunk and limb musculature, which contained a number of quail myotubes and of bispecific quail/chick myotubes. Apart from skeletal muscles, quail cells contributed sporadically to nerve envelopes and blood vessel walls in the limb. When the graft was of bispecific constitution, quail nuclei in the limb and the trunk were found exclusively in monospecific and bispecific myotubes. After implantation of differentiated embryonic or post-natal muscle tissue, quail cells in the limb contributed only sporadically to nerve envelopes and blood vessel walls, while in the trunk they also participated in the formation of muscles and tendons. It is concluded that the myogenic cells in 4 to 5-day quail premuscular masses are still able to undergo an extensive migration into the limb buds and there participate in the formation of myotubes and anatomically normal muscles. They display developmental potentialities equivalent to those of the somitic myogenic stem cells. These capacities are lost in 12-day embryonic muscles.

Notes: Schlußfolgerungen 1. Die Spindel im Innern des Eies ist sehr beweglich; das kleinste Hindernis genügt, um sie von ihrer Richtung abzulenken. 2. Es ist nicht richtig, daß die erste Furchungsspindel in den Seeigeleiern eine ganz beliebige Richtung, wie O.Hertwig meinte, annehme und infolgedessen von der Wirkung der Schwerkraft freibleibe. 3. Sie erfährt hingegen diese Wirkung immer, in welcher Lage das Ei sich auch befinde, aber sie lagert sich nicht horizontal, wie man im allgemeinen glaubt, vielmehr bildet sie mit der Horizontalen einen Winkel von 45°, wieGiglio-Tos schon bewiesen hat. 4. Im übrigen ist, wieGiglio-Tos ebenfalls bewiesen hat, diese Neigung gerade dieselbe, welche zwei bewegliche Kügelchen innerhalb einer Kugel unter der Wirkung der Schwerkraft im stabilen Gleichgewicht einnehmen, wenn die Summe ihrer Durchmesser einen gewissen Wert im Vergleiche zu demjenigen der Kugel übertrifft. 5. Es ist auch nicht richtig, daß die Spindel sich längs der Richtung der größten Massen des Protoplasmas anordnet, wie es das wohlbekannte, als empirisch bezeichnete Gesetz von O.Hertwig als gültig oder wahrscheinlich hinstellen möchte. Wenn dieses Gesetz zuträfe, so müßte die Spindel in den kugelförmigen Eiern unterschiedslos jede beliebige Lage einnehmen, wohingegen festgestellt wird, daß sie unter der Einwirkung der Schwerkraft immer eine bestimmte Richtung einnimmt. Wenn übrigens die kugelförmigen Eier in Röhren eingeführt werden, deren innere Weiten dem Durchmesser des Eies gleich sind, so erleidet dieses natürlich keinerlei Deformation und bewahrt also seine ursprüngliche Kugelform. Dennoch erfährt auch in solchen Fällen die Spindel eine offensichtliche Ablenkung, welche durch das Hindernis verursacht wird, das ihr in den Röhrenwänden während ihrer Verlängerung begegnet. 6. Die von der Spindel während der Teilung erlittenen Ablenkungen, welche von uns beobachtet wurden, stimmen genau, insoweit man das bei dieser Art von Versuchen verlangen kann, mit denjenigen überein, welche theoretisch vonGiglio-Tos bestimmt worden sind, abgesehen von den Ausnahmen, deren Erläuterung in den vorhergehenden Seiten gegeben wurde. 7. Die Ergebnisse dieser Beobachtungen sind also geeignet, zu beweisen, daß das caryokinetische Phänomen, wieGiglio-Tos behauptet, in der Bildung und dem schrittweisen Wachstum zweier Kügelchen besteht, welche danach die Tochterzellen werden. Weil dem so ist, so kann das karyokinetische Phänomen nicht vor sich gehen ohne eine bestimmte Verlängerung der Zelle, und nur mit dieser Verlängerung kann man die Ablenkung erklären, welche die Spindel erfährt, wenn sie irgendein Hindernis antrifft.