Large Shape Variations Research Articles

A method for the determination of the initial shapes of deformed xenoliths in granitoids

Measuring strain from deformed xenoliths is problematic due mainly to the large initial shape variations of these markers. A method is described which allows mean initial shape to be determined for a number of xenolith populations by displaying their logarithmic ranges (log R f max — log R f max ) on a Range diagram. The diagram contains a check on validity and allows bad samples to be recognised. Xenolith data from a deformed granite in northwest Ireland is analysed using the method.

An objective Analysis of the Boundary-Layer Thermodynamic Structure During GATE. Part II: Analysis

Profiles of potential temperature, specific humidity and moist static energy are analyzed using the objective classification method described in Part I (Jalickee and Ropelewski, 1979). These profiles, extending from the surface to 890 mb, were derived from structure sonde data taken by the Fay and the Meteor during Phase III (30 August–18 September 1974) of GATE. The technique permits an objective separation of the data into groups and subgroups based on profile shapes. The initial classification, based on the shapes of the potential temperature profiles, yields two broad categories, i.e., those corresponding to undisturbed and disturbed boundary layers. While the potential temperature profiles in these groups are relatively homogeneous, that is, they resemble each other, the specific humidity and moist static energy profiles show large shape variations in each category. To form more homogeneous groups, the data within each of the broad classes are further subclassified using moist static energy as a discriminator in the objective analysis. This analysis yields two, clearly defined, moist static energy profile types. The first, a subclass of the undisturbed group, comprises 25% of the soundings and contains profiles which exhibit clearly defined mixed, transition and cloud layers. The mean mixed-layer top for these profiles was close to 960 mb with a mean transition-layer thickness of near 35 mb. The second type, while a subclass of the disturbed group, contains profiles that are not associated with organized convective precipitation at the time of the sounding. In these profiles 27% of the total, moist static energy decreased rapidly with height in the lowest 20–30 mb, i.e., to ∼980 mb, and then became constant for the remainder of the profile. Profiles in this subclass may result from mass and energy transfers usually associated with organized deep convection.

Variability of the optical spectra of two quasars

view Abstract Citations (32) References (36) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS Variability of the optical spectra of two quasars. Netzer, H. ; Wills, B. J. ; Uomoto, A. K. ; Rybski, P. M. ; Tull, R. G. Abstract Spectroscopic monitoring of the quasars PKS 0736+01 and 3C 345 is reported for the period 1977 November through 1979 March. The emission-line intensities in both objects remained constant while large variations in continuum brightness and shape occurred. Comparison with previous data suggests that the Mg II 2798 line in 3C 345 may have remained constant in intensity over the last 13 years. The broad '3000 A bump' in the spectrum of PKS 0736+01 did not change with the continuum. The implications for the sizes of the emission-line regions in quasars and Seyfert nuclei are discussed. Publication: The Astrophysical Journal Pub Date: September 1979 DOI: 10.1086/183055 Bibcode: 1979ApJ...232L.155N Keywords: Quasars; Radio Sources (Astronomy); Seyfert Galaxies; Stellar Spectra; Brightness; Emission Spectra; Line Spectra; Stellar Spectrophotometry; Astronomy; Quasars:Optical Variations; Quasars:Spectra full text sources ADS |

The Relationship of Egg Shape to Time of Oviposition and Egg Shell Quality

Experiments were conducted to determine the relationship of egg shape to time of oviposition and egg shell quality. Eggs were collected at 2-hr intervals throughout the day and depending upon the experiment various measurements (egg weight, shape index, shell weight, shell thickness, or specific gravity) were determined.The results indicated that eggs laid during the afternoon had a higher shape index (rounder eggs) than eggs laid during the morning. The afternoon eggs also had a higher specific gravity, shell weight, shell thickness, and were smaller than eggs laid during the morning. A large variation in shape index occurred among eggs.It was concluded that the difference in shape between times of oviposition would not explain the variation in shell quality due to time of oviposition, but that the large variation in egg shape among birds is a significant factor in determining the bird’s ability to produce eggs with maximum shell thickness with a given amount of shell.

Electroluminescence (EL) from natural semiconducting (p-type) diamond

Microscopical examination in this work has shown the EL obtained from a semiconducting diamond using silver-paint electrodes to appear mainly at the negative electrode and only at very small points where the silver grains make contact with the crystal. Complications due to large variations in grain size and shape were eliminated by preparing silver-evaporated electrodes, with dimensions of the order of 1 μm. The EL brightness was found to increase with the decrease of the electrode size. An expression describing the dependence of the EL on the applied voltage and on the energy of the level to which excitation takes place was fitted to the experimental results. Detailed analysis of the EL suggested that electrons are raised by impact with holes to four discrete levels in the forbidden gap, probably from the level at 0.37 eV above the valence band present in these diamonds. The emission spectrum was found to show three peaks in the spectral range 3600–9000 Å, and indicated the existence of another peak beyond 9000 Å. All the emission bands seem to result from recombination at one common level, which should be the valence band itself or a level very close to it. Our emission spectrum fitted that given in the literature (ref. [13]) for cathodoluminescence of natural semiconducting diamond.

Sex Pheromones of Noctuid Moths. XX. Short-Range Visual Orientation by Pheromone-Stimulated Males of Trichoplusia ni1,2

Pheromone-stimulated males of the cabbage looper, Trichoplusia ni (Hubner) (Lepidoptera: Noctuidae), were observed in the laboratory for orientation and copulatory attempt behavior directed toward a pheromone source or nearby visual models positioned vertically in a cage. The models were either dried T. ni females or black paper silhouettes. When 2 models were presented simultaneously, 2 cm to the right and left of a pheromone source on a disc of filter paper, 33% of the males observed oriented to one of the models vs. 67% to the source. However, 86% of all copulatory attempts were directed toward a model vs. 14% toward the source. The models did not influence the frequency of orientation behavior of pheromone-stimulated males; they only influenced the direction of orientation. By contrast, the models influenced both the frequency and direction of copulatory attempts. All orientation and copulatory attempts were directed toward the lower apex of a model, even if that apex was the head or wing tip of a dried female. Large variations in model shape from a shape similar to a female had to be made to cause a diminution in effectiveness for directing orientation. A black paper silhouette was less effective than a normal dried female moth but was as effective as a dried female that was dyed black. Black silhouettes ½ or ¼ normal size were less effective than one of the size and shape of a female.

Migration of air bubbles, vapor figures, and brine pockers in ice under a temperature gradient

Equations are derived for the speed and direction of migration of air-, vapor-, or brine-filled triaxial ellipsoidal cavities of any orientation, and expected velocities are computed for the spherical, cylindrical, and discoidal cases that have been investigated experimentally. In the case of air bubbles agreement is only fair for approximately spherical bubbles trapped during freezing and is somewhat better for drilled cylindrical holes open to the atmosphere. The lack of agreement and the considerable scatter in the data are probably due to uncontrolled variations in pressure and shape and to the slow accumulation of frost. In the case of discoidal vapor figures the agreement is much poorer and the scatter is much greater, probably because of large uncontrolled variations in shape, air content, and temperature of the figures. Calculation of the effect of small size, for which viscous flow of the vapor is important, shows it to be negligible for the figures used in the experiments. For spherical brine pockets at temperatures a few degrees or more below freezing agreement is fairly good, considering the uncertainties in the diffusion coefficient, but at the ice point the predicted speed is about 5 times that observed, probably because the brine concentration in the pockets at this temperature was not in fact zero as required by the theory.

Endogenous bud formation in Histriculus vorax, a new asexual reproductive process in the hypotrichida.

SYNOPSIS. Histriculus vorax (Stokes) Corliss, a hypotrichous ciliate, has been separated from activated sludge and cultured monoxenically in the laboratory. The asexual life cycle has been observed and the stages of development photographed. There are large variations in shape and size of cells within clonal cultures. Both large (190–250 μ long) and small (70–140 μ long) cells are capable of normal asexual binary fission but only the large cells are able to grow endogenous buds, which, when mature, are extruded through the body wall of the mother cell. Newly deposited buds can either develop directly into an embryonic form, or, if unfavorable conditions prevail, first encyst. Similar embryonic stages bearing caudal and frontal cirri are produced both by direct development and by excystment of the encysted bud. Embryos develop rapidly into trophic forms which finally grow into small adults capable of asexual binary fission. During binary fission the nuclei behave as described previously for other members of the Oxytrichidae. A reorganization band forms at the outer end of each macronucleus, and these bands move along the macronuclei towards each other, finally disappearing at the inner ends. A fusion nucleus is then formed which splits into 4 pieces, 2 of which pass to the proter and 2 to the opisthe. During bud formation the reorganisation bands form and move as in binary fission. No fusion nucleus is formed, but the macronuclei divide immediately after reorganization, and the anterior macronucleus of each pair so produced migrates to the budding region. The infraciliature of H. vorax resembles that of Opisthotricha monspessulana.‘Erratic’ kinetosomes, which are present in the adult, divide during binary fission and so produce the infraciliature of the proter and opisthe. During bud formation the budding region receives a number of these ‘erratic’ kinetosomes from the mother cell, and these divide to form the infraciliature of the bud.