THE CYTOLOGY OF THREE HYBRIDS INVOLVING HORDEUM JUBATUM L.: THE CHIASMA DISTRIBUTIONS AND THE OCCURRENCE OF PSEUDO RING-BIVALENTS IN GENETICALLY INDUCED ASYNAPSIS

1960 ◽  
Vol 38 (1) ◽  
pp. 69-85 ◽  
Author(s):  
E. B. Wagenaar
Keyword(s):  
Secale Cereale ◽  
The Other ◽  
Random Pattern ◽  
Secondary Effect ◽  
Chiasma Distribution ◽  
Other Hand ◽  
Ring Bivalents ◽  
Secale Cereale L ◽  
Hordeum Jubatum ◽  
Theoretical Considerations

Three hybrids, two of Hordeum jubatum L. × Secale cereale L. var. Prolific, and one of H. jubatum × H. bulbosum L., were examined cytologically. The two genomes of H. jubatum showed autosyndesis in the H. jubatum × S. cereale hybrids. It was concluded, therefore, that H. jubatum has two closely related genomes.One of the H. jubatum × S. cereale hybrids displayed weak asynapsis. The H. jubatum × H. bulbosum hybrid, on the other hand, showed strong asynapsis, although the prophase pairing was almost complete. It was concluded that the asynapsis of this latter hybrid was due to interaction of genes of the H. jubatum and the H. bulbosum genomes.The chiasma distributions of the hybrids were tested for randomness by Gaul's formula. It was found that the chiasma distributions of the H. jubatum × S. cereale hybrids followed a random pattern, whereas in the H. jubatum × H. bulbosum hybrid the distribution was disturbed by a secondary effect. Cytological observations and theoretical considerations led to the conclusion that the occurrence of pseudo ring-bivalents had disturbed the apparent chiasma distribution in the H. jubatum × H. bulbosum hybrid. A theory of the origin of pseudo bivalents and an evaluation of Gaul's formula is presented.

Experimental Determination of the Cinematic Misfit within the Transmission of a 4x4 Vehicle that Leads to Self-Generated Torque along the Vehicle’s Inter-Axle Driveline

2014 ◽  
Vol 659 ◽  
pp. 262-267
Author(s):  
Marian Truta ◽  
Marin Marinescu ◽  
Octavian Alexa ◽  
Radu Vilau ◽  
Valentin Vinturis
Keyword(s):  
Experimental Determination ◽  
Experimental Methods ◽  
The Self ◽  
The Other ◽  
Other Hand ◽  
Theoretical Considerations ◽  
The Way

Present paper aims at revealing a way to determine the cinematic misfit within a 4x4 vehicle’s inter-axle driveline, which is eventually the reason of the self-generated torque occurrence. We used experimental methods to determine the magnitude of the cinematic misfit. Within this frame, we used a vehicle that has a longitudinal (inter-axle) differential and we locked it, actually forcing the longitudinal transmission to work without differentiating the angular speeds on its output shafts. On the other hand, the tire radii were different, inducing the above-mentioned cinematic misfit that we were looking for. We also present the way we fit the transducers on the vehicle’s driveline components to measure the needed parameters. The paper also presents some theoretical considerations regarding the occurrence of the cinematic misfit and its way of generating closed power loops within the vehicle’s transmission.

SPRING AND SUMMER PASTURES FOR SOUTHWESTERN SASKATCHEWAN

1979 ◽  
Vol 59 (2) ◽  
pp. 339-342 ◽  
Author(s):  
M. R. KILCHER ◽  
T. LAWRENCE
Keyword(s):  
Secale Cereale ◽  
Perennial Grasses ◽  
The Other ◽  
Secale Cereale L

Fall rye (Secale cereale L.), Russian wild ryegrass (Elymus junceus Fisch.) and Altai wild ryegrass (Elymus angustus Trin.) pastures were compared over a 4-yr period. Cows with calves were used as grazing animals for 2 yr and yearling steers were used for the other 2 additional yr. The two perennial grasses provided about twice as many grazing days as did fall rye. Average daily liveweight gains were highest for fall rye. Altai wild ryegrass produced 50% more liveweight gain per hectare than Russian wild ryegrass and nearly 100% more than fall rye.

Practical Seismology and Seismic Prospecting. L. D. Leet. D. Appleton‐Century Company, New York, 1938. x+430 pp. $6.00. (The Century Earth Science Series, Kirtley F. Mather, Editor.)

Geophysics ◽  
1938 ◽  
Vol 3 (4) ◽  
pp. 358-358
Author(s):  
M. M. Slotnick
Keyword(s):  
New York ◽  
Wave Propagation ◽  
Earth Science ◽  
The Other ◽  
Elastic Theory ◽  
Seismic Prospecting ◽  
Other Hand ◽  
Instrumental Technique ◽  
Theoretical Considerations

To most people interested in seismic prospecting, the title of the volume will perhaps be somewhat misleading. A large part of the book is devoted to earthquake lore in general; and those early chapters devoted to the geology of this subject, the reviewer found intensely interesting. On the other hand, the treatment on seismic prospecting, as the term is generally understood, is rather inadequate. One feels that the author might have done far more with the various theoretical considerations of instrumental technique, elastic theory, wave‐propagation and such. The treatment, mathematical and physical, cannot be considered convincing—in fact this writer feels that it is definitely superficial in most places.

scholarly journals X. On the mineral constituents of meteorites

1870 ◽  
Vol 160 ◽  
pp. 189-214 ◽  
Keyword(s):  
Chemical Separation ◽  
The Other ◽  
Fine Grained ◽  
Other Hand ◽  
Mineralogical Investigation ◽  
The One ◽  
Theoretical Considerations ◽  
Mineral Constituents ◽  
Insoluble Portion

I. The applications of the Microscope in the investigation of Meteorites . The mineralogical investigation of a meteoric stone presents difficulties very similar to those which have hitherto rendered the analyses and descriptions of many of the finer-grained terrestrial rocks unsatisfactory ; for a meteoric stone is in fact a fragment of a rock, though formed under conditions in some respects widely differing from those which have produced the rocks of our globe. The difficulties alluded to arise from the minute size and imperfectly developed crys­tallisation of the mineral constituents alike of the rock and the aërolite ; and they have in general baffled the efforts of the chemist on the one hand to effect their separate analyses, and of the crystallographer on the other hand to determine the forms of these constituents. The chemist indeed has endeavoured to overcome the difficulty by attempt­ing a chemical separation of the constituent minerals of these fine-grained mixtures into one group of such as are soluble and another group of those which are insoluble in acids, and then treating the numbers obtained from the analyses of these groups by the light of theoretical considerations founded on the formulae and properties of known minerals. This method is necessarily only an approximative one. Even granting that by its means, we could divide a rock into two classes of ingredients, which we cannot in fact accurately do, there remains the question of how to separate from each other the mingled minerals in, for instance, its insoluble portion.

scholarly journals Log Files as a Tool for Improving Internet Dictionaries

2017 ◽  
Vol 18 (34) ◽  
pp. 117
Author(s):  
Henning Bergenholtz ◽  
Mia Johnsen
Keyword(s):  
Empirical Research ◽  
The Other ◽  
User Behaviour ◽  
Log Files ◽  
Other Hand ◽  
Types Of Information ◽  
Dictionary Use ◽  
Theoretical Considerations

In their advertisements, dictionary publishers often praise their dictionaries for taking into account the exact needs of the users. Until the beginning of the 1980s, however, no theoretical contributions on dictionary use were available, neither in the form of purely theoretical considerations nor in the form of empirical research. Since then, the situation has changed completely. Such a large number of user surveys have been carried out that it is no longer possible to give a complete overview. Nevertheless, this has led to no significant improvement of the situation as the majority of these surveys are not related to concrete examples of dictionary use. The surveys, which have always been concerned with printed dictionaries, have therefore not contributed to substantial improvements of dictionary conception. In the case of internet dictionaries, on the other hand, technical possibilities enable lexicographers to monitor user behaviour in a different and much more precise way. Analyses of log files reveal exactly which lemmas and which types of information have been requested, and, perhaps more significantly, which lemmas and which types of information have been requested but were not found in the dictionary. Furthermore, log files allow lexicographers to see the types of information which have not, or not yet, been searched for. All in all, log files may thus be used as a tool for improving internet dictionaries – and perhaps also printed dictionaries – quite considerably.

scholarly journals On Cluster Calculation for Amorphous Tetrahedrally Bonded Semiconductors

1997 ◽  
Vol 20 (1) ◽  
pp. 1-5
Author(s):  
M. A. Grado-Caffaro ◽  
M. Grado-Caffaro
Keyword(s):  
Electronic Spectra ◽  
Amorphous Semiconductors ◽  
The Other ◽  
Cluster Calculation ◽  
Other Hand ◽  
Valence States ◽  
Theoretical Considerations ◽  
Operational Methods ◽  
Tetrahedrally Bonded

This article consists of an approach to the calculation of the density of valence states in tetrahedrally bonded amorphous semiconductors and, on the other hand, the paper contains theoretical considerations on electronic spectra related to the results obtained by the authors concerning cluster calculation. The exposition is centered on III–V compounds. Moreover, operational methods are used to perform certain computations related to the previous subjects.

A study of cometary eruptions through OH radio-lines

1999 ◽  
Vol 173 ◽  
pp. 249-254
Author(s):  
A.M. Silva ◽  
R.D. Miró
Keyword(s):  
Short Duration ◽  
Growth Curves ◽  
The Other ◽  
Initial Mass ◽  
Radio Lines ◽  
Other Hand ◽  
Sudden Rise

AbstractWe have developed a model for theH2OandOHevolution in a comet outburst, assuming that together with the gas, a distribution of icy grains is ejected. With an initial mass of icy grains of 108kg released, theH2OandOHproductions are increased up to a factor two, and the growth curves change drastically in the first two days. The model is applied to eruptions detected in theOHradio monitorings and fits well with the slow variations in the flux. On the other hand, several events of short duration appear, consisting of a sudden rise ofOHflux, followed by a sudden decay on the second day. These apparent short bursts are frequently found as precursors of a more durable eruption. We suggest that both of them are part of a unique eruption, and that the sudden decay is due to collisions that de-excite theOHmaser, when it reaches the Cometopause region located at 1.35 × 105kmfrom the nucleus.

Closing the GAP—A 5Å Scanning Microscope

1969 ◽  
Vol 27 ◽  
pp. 6-7
Author(s):  
A. V. Crewe
Keyword(s):  
Normal Form ◽  
The Other ◽  
Resolving Power ◽  
Scanning Microscope ◽  
Conventional Microscope ◽  
Other Hand ◽  
Closing The Gap ◽  
Thermal Sources ◽  
Better Than ◽  
Transmission Microscope

We have become accustomed to differentiating between the scanning microscope and the conventional transmission microscope according to the resolving power which the two instruments offer. The conventional microscope is capable of a point resolution of a few angstroms and line resolutions of periodic objects of about 1Å. On the other hand, the scanning microscope, in its normal form, is not ordinarily capable of a point resolution better than 100Å. Upon examining reasons for the 100Å limitation, it becomes clear that this is based more on tradition than reason, and in particular, it is a condition imposed upon the microscope by adherence to thermal sources of electrons.

Life Beyond 1MeV

1980 ◽  
Vol 38 ◽  
pp. 30-33
Author(s):  
K.H. Westmacott
Keyword(s):  
Electron Microscopy ◽  
Past Experience ◽  
The Other ◽  
Good Case ◽  
Other Hand ◽  
The U.S

Life beyond 1MeV – like life after 40 – is not too different unless one takes advantage of past experience and is receptive to new opportunities. At first glance, the returns on performing electron microscopy at voltages greater than 1MeV diminish rather rapidly as the curves which describe the well-known advantages of HVEM often tend towards saturation. However, in a country with a significant HVEM capability, a good case can be made for investing in instruments with a range of maximum accelerating voltages. In this regard, the 1.5MeV KRATOS HVEM being installed in Berkeley will complement the other 650KeV, 1MeV, and 1.2MeV instruments currently operating in the U.S. One other consideration suggests that 1.5MeV is an optimum voltage machine – Its additional advantages may be purchased for not much more than a 1MeV instrument. On the other hand, the 3MeV HVEM's which seem to be operated at 2MeV maximum, are much more expensive.

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