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Comparative Growth Rates Of Different Strains Of Rhizobium Meliloti, R.H. Walker, Dean A. Anderson

Proceedings of the Iowa Academy of Science

The growth rates of two strains of Rhizobium meliloti were measured when the organisms were grown in a nitrogen-free medium and in a medium containing nitrate nitrogen. The strains used differed widely in their ability to aid the host plant in symbiotic nitrogen fixation. They also differed somewhat in cultural characteristics.

Secondary Emission Of Electrons From Metals, Paul L. Copeland

Proceedings of the Iowa Academy of Science

When electrons are incident upon a metal surface, it is observed that electrons also leave the surface. The amount of this "secondary emission" depends upon the velocity of the incident electrons, upon the metal used as a target, and upon the previous heat treatment of the metal. The results obtained in this investigation indicate that secondary emission is very low for incident electrons of low energy; that it increases rapidly as the energy of impact is raised; that it reaches a broad maximum at a position characteristic of the metal and then declines. Metals of low work function give the …

Can The Ayres Spelling Scale Be Relied On For Measuring The Individual Class Achievement?, E. C. Denny

Proceedings of the Iowa Academy of Science

Twenty words were selected at random from column Q of the Ayres Spelling Scale. These words were given as a dictated spelling test to 29 pupils in the 5th grade of the I. S. T. C. Training School. The papers were scored and it was also determined how many times each word was missed. The ten easiest words were then considered as one test and the ten most difficult words as a second test.

Effects Of Various Amounts Of Calcium Carbonate On The Degree Of Saturation Of Some Iowa Soils With Bases, R. H. Walker, P. E. Brown

Proceedings of the Iowa Academy of Science

Untreated Grundy silt loam was found to contain 9.30 M.E. of exchangeable hydrogen and 14.03 M.E. of exchangeable bases per 100 grams of soil in the base-exchange complex. Six months after the same soil had been treated with chemically pure calcium carbonate at the rate of six tons per acre the exchangeable hydrogen content was only 1.15 M.E. and the exchangeable base content was 24.54 M.E. The calcium carbonate treatment, therefore, increased the degree of saturation with bases from 60.13 per cent to 95.52 per cent.

Table Of Contents

Proceedings of the Iowa Academy of Science

No abstract provided.

Effect Of Piezo Electric Oscillations On X-Ray Patterns Of Quartz, P. H. Carr, G. W. Fox

Proceedings of the Iowa Academy of Science

Experiments have been made to determine the amplitude of vibration of the atoms in a quartz lattice due to piezo electric oscillations. A series of Laue X-ray patterns have been made of quartz plates cut at various angles to the electric axes. Very marked intensity differences are apparent between the patterns made with the plates oscillating and not oscillating.

Studies In The Selection For Susceptibility And Resistance To Anaphylactic Shock In Guinea Pigs, E. W. Shrigley

Proceedings of the Iowa Academy of Science

In 1927 the foundation stock for this experiment was picked at random from the guinea pig colony of the Genetics Department at Iowa State College. Since then three generations of individuals, selected both for resistance and susceptibility to protein reaction, have been obtained.

In Memoriam: Bird Thomas Baldwin; J. M. Fulton; John Littleton Tilton; Flora May Tuttle; M. F. Arey; Abram Owen Thomas; Joseph A. Treganza; Louis H. Pammel, George D. Stoddard, Charles Keyes, Henry S. Conrad, E. J. Cable, James H. Lees, B. Shimek

Proceedings of the Iowa Academy of Science

No abstract provided.

The Production Of Kynurenic Acid From Tryptophane Derivatives, Clarence P. Berg

Proceedings of the Iowa Academy of Science

Tryptophane, when administered to certain animals, is converted into kynurenic acid. Use has been made of this fact in the study of possible cleavage of tryptophane derivatives in the alimentary tract and in the body proper.

The Unsoundness Of Certain Types Of Rocks, Mark Morris

Proceedings of the Iowa Academy of Science

Geologists, working in cooperation with highway engineers, have been of great assistance to them, and of great economic service to the public in searching out sources of material, in classifying and identifying rock formations, and in passing judgment upon the suitability of different rocks for use in highway projects. More recently geologists have rendered great assistance in the study of slides in earth embankments in both the cut and fill sections. All of these and innumerable other associations have developed the mutual respect and spirit of cooperation now existing between geologists and highway engineers. This seems particularly fitting since the …

Larger Prospect Of Our Loess Mantle, Charles Keyes

Proceedings of the Iowa Academy of Science

It is exceedingly unfortunate and disturbing that the loess deposits of our state should ever have been mixed up with the glacial tills, when, indeed, they have no more to do with glaciation than the bed-rock itself. Loess, being mainly wind-borne dust derived from Southwestern deserts, and a deposit being continuously laid down far and wide, inside and outside of the glaciated areas, throughout glacial, a swell as interglacial, times, is doubtless being deposited over our state as rapidly and as extensively as loess ever accumulates. It should not, therefore be associated, genetically or otherwise, with our glacial deposits; but …

Progress In The Analysis Of Cosmic-Ray Observations (Ii), Le Roy D. Weld

Proceedings of the Iowa Academy of Science

One year ago the writer reported to this Academy the results of some preliminary calculations of the intensities of the three components assumed by Millikan to compose the cosmic radiation, based upon his last published data.1 At that time the Academy was so kind as to set apart a grant for a continuance of this research. Soon afterward, Dr. Millikan informed me that he was engaged upon a more elaborate series of depth-ionization measurements which promised greater precision, and extended the hope that the results would be available by fall. It was, however, not until February that the new data …

Ultra Violet Absorption Spectra Of Carotene And Vitamin A, Jay W. Woodrow, J. B. Philipson

Proceedings of the Iowa Academy of Science

Using a sensitive photo electric spectrophotometer, carotene derived from carrots and dissolved in an oil, has been found to exhibit an absorption band in the region 325-330 Mμ. An absorption band in this region has been shown by Morton & Heilbron to be characteristic of vitamin A in fats derived from animal sources. The appearance of this band in carotene from a vegetable source, establishes an even closer relationship between these two growth-promoting factors.

Phosphorescence In A Photoelectric Cell Of Fused Quartz, George V. Emery

Proceedings of the Iowa Academy of Science

While using a quartz spectrograph and a fused quartz photoelectric cell, a large leak was observed immediately after shutting off the exciting light. This was apparently due to a phosphorescence of the fused quartz. Only a few seconds exposure sufficed to give the saturation value. The current decreased according to the regular law of decay of phosphorescence reaching zero in about one minute.

Exchange Of Oestrous And Corpus Luteum Hormones In Parabiotic Female Rats, Robert T. Hill

Proceedings of the Iowa Academy of Science

Normal female rats in parabiosis have a tendency to run oestrous cycles independent of each other. Though sufficient hormones are exchanged to disturb somewhat the oestrous cycles of each twin member this interference does not result in synchronized cycles. During pregnancy of one of the twins the oestrous cycle of the non-pregnant animal is almost entirely inhibited by the action of the corpus luteum hormone from the pregnant member. This same phenomenon persists after parturition as long as the mother nurses her litter, which must be due to the activity of the hormone of corpus luteum of lactation. Also the …

Some Nitrification Studies On An Alkali Soil In Iowa, Sanford M. Smith, F. B. Smith

Proceedings of the Iowa Academy of Science

So-called "alkali" spots are somewhat common in certain parts of Iowa. They occur mainly in the Wisconsin drift soil area but occasionally areas are also found in the Iowan drift soil area. In many cases the peat and alkali areas appear in association, the peat occurring in an old lake bed or depression while the alkali spots are found on the uplands adjacent to the peat, occasionally forming a ring around the peat bed.

Effects Of Soil Aeration On Plant Growth And Root Development, W. F. Loehwing

Proceedings of the Iowa Academy of Science

Considerable is known concerning the immediate effect on root growth of excess carbon dioxide and shortage of oxygen in the soil. The ecologic importance of soil atmosphere in relation to root growth has also been studied. Very little work has been done on the formative and metabolic effects of continuous liberal soil aeration on plants so grown. A preliminary report is herewith presented of the formative effects of optimal air supply upon root and top growth in several types of plants whose roots differ in their oxygen requirements.

Notes On Iowa Mosses. Iv, Lucy M. Cavanagh

Proceedings of the Iowa Academy of Science

Work on the moss flora of Iowa at the State University in the past year has added fourteen species and varieties to the state list. These forms represent nine families and thirteen genera, one family (Fabroniaceae) and two genera (Fabronia and Amphidium) being new to the state.

Contemporaneous Deformation In The Cedar Valley Limestone, A. C. Tester

Proceedings of the Iowa Academy of Science

Occasional references have been made in geological literature to the brecciation which marks certain zones of the Cedar Valley limestone of eastern Iowa. Additional data is presented in this paper on this subject. A new type of structure which appears as slickensides and grooves is described and interpreted as the result of movement prior to complete hardening of the lime ooze. There is a suggestion that this movement may be partially responsible for the formation of the stylolites which also occur in the same bed.

Origin Of The Pebble Band On Iowan Till, George F. Kay

Proceedings of the Iowa Academy of Science

According to one view the pebble band on the Iowan till is the result of wind action in a marginal area during the retreat of the Iowan ice. An alternative interpretation is that the pebble band is the result chiefly of the erosion of Iowan till by running water, considerable time having been involved in its formation.

Some Recent Improvements In The Galvanic Techniques, Christian A. Ruckmick

Proceedings of the Iowa Academy of Science

Our latest experimental results verify some previous tentative conclusions that mental and physical fatigue cause an increase in O's resistance which is fairly uniform but presents still some anomalous cases. Blood pressure almost uniformly increases. We have also perfected the device which photographs the deflections obtained from the Hathaway apparatus.

Instinct Or Intelligence In The Great Golden Digger?, Roy L. Abbott

Proceedings of the Iowa Academy of Science

"

To know everything and to know nothing according as it acts under normal or exceptional conditions: that is the strange antithesis presented by the insect race." So said that profound student of insects, Fabre, after an immense amount of experimentation. No one has written so entertainingly about insects as has this great Frenchman; few have equaled and none excelled him in the wealth and variety of his observations upon them. But he was trained as a physicist and a mathematician and consequently, brought into his biological studies the viewpoint of the inorganic sciences.

Aspergillus Niger As An Indicator Of Available Phosphorus In The Soil, F. E. Schlots, F. B. Smith, P. E. Brown

Proceedings of the Iowa Academy of Science

There have been numerous attempts in recent years to develop a method which would indicate accurately the phosphorus needs of the soil. Biological methods and chemical methods have been suggested, but at some time or other all the methods have failed to give satisfactory results.

The Effect Of Phosphorus On Nitrogen Fixation By Azotobacter, L. G. Thompson Jr., F. B. Smith

Proceedings of the Iowa Academy of Science

Since the isolation of species of Azotobacter by Beijerinck in 1901, many investigations have been conducted to determine the mineral requirements of the organisms of this genus. In most of this work it has been found that increasing concentrations of phosphates up to a certain limit, greatly stimulate the growth of Azotobacter. The question may be asked-- are the rather large amounts of phosphorus which seem to be necessary for maximum growth assimilated by the organisms or do they serve another purpose, such as a stimulant or a buffer in the culture medium?

Remedial Measures In Reading At The College Level, Francis P. Robinson

Proceedings of the Iowa Academy of Science

Reading ability is highly related to school success. College freshmen with inferior ability have a high scholastic mortality and those that do remain in school are hampered in gaining knowledge. Therefore, a remedial unit has been inaugurated at the University of Iowa to aid the lowest quarter in reading ability. A clinical method is used, each case being handled individually which allows each difficulty to be treated and makes for better rapport. A complete analysis is made of the student's abilities and weaknesses and work is directed to remove these defects. Various methods of reading and their uses are also …

Index

Proceedings of the Iowa Academy of Science

No abstract provided.

Radio And The Outer Atmosphere

Science Bulletin

In investigating the possibilities of short-wave radio the surprising fact was discovered that although short waves may often be clearly received at distances of thousands of miles from stations with very little power, it is difficult or impossible to detect them at nearby points, 30 to 300 miles away. This can be understood if the upper atmosphere acts like a reflector.

About Atmospheric Electricity, L. Begeman

Science Bulletin

Our atmosphere is electrified at all times. During the summer the average increase of potential from the earth's surface up is about 100 volts for one meter of ascent. This potential gradient, however, diminishes with increasing altitude until at the height of one mile it is only 25 volts per meter. During the winter the atmosphere is much more in tensely electrified. The average increase of electrical potential near the earth 's surface during this season is as much as 250 volts per meter of ascent.

The Antioxidant Of Lettuce, H. S. Olcovich, H. A. Mattill

Proceedings of the Iowa Academy of Science

The unsaponifiable lipids of lettuce were fractionally crystallized from a number of organic solvents. The distribution of vitamin E was determined by the effects on female rats on a sterility producing ration; that of the antioxidant, by the capacity to prolong the induction period of an autoxidizable fat mixture. The antioxidant could be separated by extracting a petroleum ether solution with 92% methyl alcohol. A concentrate of the antioxidant was secured by distillation in vacuo, and the compound crystallized from the fraction distilling from 160-180°. It was purified by crystallization from CHC1₃. Formula: C₁₃H₁₄O …

Evidence Of Energy Exchanges Accompanying Scattering Of Atoms By Crystals, H. A. Zahl, A. Ellett

Proceedings of the Iowa Academy of Science

The distribution of mercury atoms scattered from NaCl KCl, KBr KI has been studied by means of an ionization gauge as a function of angle of incidence and temperatures of scatterer and incident beam. The direction of maximum intensify makes an angle with the crystal normal not equal to the angle of incidence but always slightly less.