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Articles 32701 - 32730 of 32960

Full-Text Articles in Life Sciences

Anthocyan Pigments, Paul B. Sears Jun 1922

Anthocyan Pigments, Paul B. Sears

Papers in Ecology

Noack has found rhamnose-free flavonol diglucosides to be much more abundant in green leaves than has generally been supposed. In such leaves as he studied he was able to establish the existence of flavonol-anthocyan in couples of similar glucosidal nature, but secured no evidence of aromatic nucleus composition in such cases. He suggests that these couples function as a reduction mechanism during photosynthesis.


Corn Investigations, T. A. Kiesselbach Jun 1922

Corn Investigations, T. A. Kiesselbach

Nebraska Agricultural Experiment Station: Historical Research Bulletins

The purpose of the investigations reported in this bulletin has been primarily to determine some of the underlying principles involved in corn improvement. The work comprises a study of some of the physiological characteristics of the crop together with a comparison of various selection, breeding, and cultural practices in their relation to grain yield.


The Preparation Of Laboratory Specimens As An Aid To The Diagnosis Of Animal Diseases, L. Van Es, L. V. Skidmore Jun 1922

The Preparation Of Laboratory Specimens As An Aid To The Diagnosis Of Animal Diseases, L. Van Es, L. V. Skidmore

Nebraska Agricultural Experiment Station: Historical Circulars

Many problems in connection with animal diseases require for their solution the application of methods which can only be undertaken at properly equipped laboratories. This ordinarily involves the collection, packing, and shipping of samples of specimens. The manner in which this is done is a most important factor and to a very large extent is responsible either for the success or for the failure of the undertaking. The discussion of the subject to which the following pages are devoted is taken in hand in the hope that it may provide guidance to the veterinarians and others who may have occasion …


The Common Intestinal Roundworm Of Swine (Ascaris Lumbricoides), H. M. Martin Jun 1922

The Common Intestinal Roundworm Of Swine (Ascaris Lumbricoides), H. M. Martin

Nebraska Agricultural Experiment Station: Historical Circulars

The large intestinal roundworm of pigs is a very common parasite and is probably present in every hog raising district of Nebraska. Up until the last few years the true nature of this parasite was unknown. Little did we realize the actual harm done by this worm; but through the scientific investigations of Stewart, Ransom, and others we now know that this parasite causes heavier losses to the breeder and feeder of swine than any other now common in Nebraska.


Variations In Cytolgoy And Gross Morphology Of Taraxacum, I. Cytology Of Taraxacum Laevigatum, Paul B. Sears Apr 1922

Variations In Cytolgoy And Gross Morphology Of Taraxacum, I. Cytology Of Taraxacum Laevigatum, Paul B. Sears

Papers in Ecology

These investigations are the outgrowth of a study, begun in 1914 at the instance of the late Professor C. E. Bessey, of parthenogenesis in Taraxacum vulgare (Lam.) Schrk. and T. laevigatum ( Willd.) DC. These two species are the common ones in central United States, being respectively designated as Leontodon taraxacum L. and L. erythrospermum (Andrz.) by Britton and Brown (3). In 1917 the existence of ameiotic parthenogenesis in both species was confirmed (23) and certain pollen abnormalities briefly described. These abnormalities have invited more critical analysis as a means of throwing light upon certain phases of variation …


Hog Houses For Nebraska, O. W. Sjogren, I. D. Wood Mar 1922

Hog Houses For Nebraska, O. W. Sjogren, I. D. Wood

Nebraska Agricultural Experiment Station: Historical Circulars

The material contained in this bulletin is a culmination of several years' study and investigation of the different types of hog houses used in Nebraska. It is realized that the plans given will not suit all conditions that may arise, but an effort has been made to bring out the essential factors so that the plans may serve as a guide in planning a house suited to particular conditions.


Insect Pests Of Stored Grains And Their Control, M. H. Swenk Feb 1922

Insect Pests Of Stored Grains And Their Control, M. H. Swenk

Nebraska Agricultural Experiment Station: Historical Circulars

In Nebraska there are about 20 species of insects that injure stored grain more or less. Some are beetles and their larvae, others are the caterpillars of small moths. To the farmer all are "weevil," although that name is really properly applied only to two beetle species-the granary weevil and the rice weevil. The following paragraphs and illustrations will describe the several more important stored grain pests to be found in this State, so that the farmer may recognize the particular pest or pests that are doing the injury to his grain, and may then apply the proper remedy.


The Physiology Of The Respiration Of Fishes In Relation To The Hydrogen Ion Concentration Of The Medium, Edwin B. Powers Jan 1922

The Physiology Of The Respiration Of Fishes In Relation To The Hydrogen Ion Concentration Of The Medium, Edwin B. Powers

Papers in Systematics and Biological Diversity

Within recent years much has been added to the knowledge concerning the mechanism of the respiratory function of the blood. Haldane and Priestley (1905) have shown that, at least in the higher animals, the respiratory movements are affected by the carbon dioxide tension of the arterial blood. It has been shown definitely (Hasselbalch, 1912 and citations) that the exciting agent is the hydrogen ion concentration of the blood bathing the respiratory center.

Krogh and Leitch (1919) undertook to study the respiratory function of the blood of fishes in view of the knowledge of the influence of temperature upon the dissociation …


The Flat-Headed Apple-Tree Borer, Fred E. Brooks Jan 1922

The Flat-Headed Apple-Tree Borer, Fred E. Brooks

United States Department of Agriculture-Agricultural Research Service / University of Nebraska-Lincoln: Faculty Publications

The flat-headed apple-tree borer, a serious orchard pest throughout the greater part of United States, is found from the Atlantic to Pacific and from Florida and Texas to Canada.

The larva, or grub, of this insect (which in the adult stage is a medium-sized beetle) bores in the bark and wood of a great variety of trees, but is best known as an enemy of apple, pear, peach, and other cultivated fruit trees. Its depredations are felt in almost every locality where orchards have been planted.

Fortunately, this borer almost invariably confines its attacks to the sunny sides of trees …


Relation Of Hardpan To Root Penetration In The Great Plains, J. E. Weaver, John Crist Jan 1922

Relation Of Hardpan To Root Penetration In The Great Plains, J. E. Weaver, John Crist

Department of Agronomy and Horticulture: Faculty Publications

During the excavation of root systems of native and crop plants through- out the Great Plains region during the past five years (Weaver, 1919,1920, 1922) contact has been made in more than thirty fields with the so-called hardpan. Such a layer of soil underlies much of this area of low rainfall, at depths varying from 15 inches to 3 feet. It varies from 8 inches to over 1.5 feet in thickness. In connection with studies on the physical and chemical composition of the soils and their seasonal water-content under natural and cropped conditions, a more detailed study has been made …


Genetic Interrelations Of Two Andromonoecious Types Of Maize, Dwarf And Anther Ear, R. A. Emerson, Sterling H. Emerson Jan 1922

Genetic Interrelations Of Two Andromonoecious Types Of Maize, Dwarf And Anther Ear, R. A. Emerson, Sterling H. Emerson

Department of Agronomy and Horticulture: Faculty Publications

Attention was called by Montgomery (1906)to the occasional appearance

of perfect flowers in the staminate inflorescence of maize and similar

cases were reported by Kempton (1913). Montgomery (1911) described

with illustrations a true-breeding type of semi-dwarf dent maize, the ears

of which were perfect-flowered. Perfect-flowered maize was described

and illustrated also by Blaringhem (1908, pp. 180-183). East and

Hayes (1911, pp. 13, 14) noted and illustrated a perfect-flowered sweet

corn. Weatherwax (1916, 1917) showed that typically pistillate

flowers of maize exhibit in microscopic sections the rudiments of stamens

and that staminate flowers show rudiments of pistils.


Development And Activities Of Roots Of Crop Plants: A Study In Crop Ecology, J. E. Weaver, Frank C. Jean, John W. Crist Jan 1922

Development And Activities Of Roots Of Crop Plants: A Study In Crop Ecology, J. E. Weaver, Frank C. Jean, John W. Crist

Department of Agronomy and Horticulture: Faculty Publications

Introduction
I. INVESTIGATIONS AT PERU, NEBRASKA, IN 1919.
University No. 21 oats, Avena sativa
Swedish Select oats, Avena sativa
Durum wheat, Triticum durum
Marquis wheat, Triticum aestivum
Manchuria barley, Hordeum vulgare
Corn, Zea mays indentata
Earlier investigations of corn
Potato, Solanum tuberosum
Earlier investigations of potatoes
Comparison of root systems
Environmental conditions of growth
Summary of root development
II. INVESTIGATIONS AT LINCOLN, NEBRASKA, IN 1919 AND 1920.
Oats, Avena sativa
Barley, Hordeum vulgare
Wheat, Triticum aestivum
Alfalfa, Medicago sativa
Sweet clover, Melilotus alba
Comparison of root systems
III. INVESTIGATIONS AT PHILLIPSBURG, KANSAS, IN 1920.
Oats, Avena sativa
Barley, Hordeum vulgare …


New Species And Collections Of Arrhenuri: 1921, Ruth Marshall Oct 1921

New Species And Collections Of Arrhenuri: 1921, Ruth Marshall

School of Biological Sciences: Faculty Publications

The genus Arrhenurus, the largest group of the water mites, continues to yield new material from collections in lake regions. The new species described in this paper came from regions as far apart as Canada and China; while additional notes on already described species are based on material secured in several states of northeastern United States, some of them from new localities. Through the kindness of Professor N. Gist Gee, of Soochow University, material was secured for the description of new species from China. Professor Frank Smith and Dr. H. R. Vancleave, of the University of Illinois, were good enough …


Vegetation Mapping, Paul B. Sears Apr 1921

Vegetation Mapping, Paul B. Sears

Papers in Ecology

The value of accurate maps of native vegetation as a basis for very practical generalizations can not be questioned. It is obvious that an essential condition for getting accurate maps of large areas is the existence of precise maps of smaller component ones. At present very few precise local maps are available, but it is to be hoped that botanists throughout the country will begin to supplement the efforts of a few of their number who are doing map work of permanent and general' value.


The Regional Adaptation Of Corn In Nebraska, T. A. Kiesselbach, F. D. Keim Apr 1921

The Regional Adaptation Of Corn In Nebraska, T. A. Kiesselbach, F. D. Keim

Nebraska Agricultural Experiment Station: Historical Research Bulletins

The purpose of this investigation was to determine some of the factors involved in the regional adaptation of corn. The procedure has been to make a comparative study of native corn types, known to be locally adapted to various regional areas in Nebraska through long growth there. The work has been confined to the single species group - Zea mays indentata. No one variety of a common source is grown throughout the state, and therefore it has been impossible to keep within a single variety. It would appear that the data should indicate morphological and histological plant characteristics involved …


The Nebraska Tractor Law And Rules For Official Tractor Tests, O. W. Sjogren, E. E. Brackett, C. W. Smith, F. R. Nohavec Apr 1921

The Nebraska Tractor Law And Rules For Official Tractor Tests, O. W. Sjogren, E. E. Brackett, C. W. Smith, F. R. Nohavec

Nebraska Agricultural Experiment Station: Historical Circulars

The Nebraska Tractor Law, which became effective July 15, 1919, was enacted to encourage the manufacture and sale of improved types of tractors and to contribute to a more successful use of the tractor for farming. It was thought that the best method of accomplishing these objects would be to require a tractor of each model sold in the State to be tested at the State University and to have the results of these tests made public.


A New Blood Fluke From Turtles, Henry Baldwin Ward Mar 1921

A New Blood Fluke From Turtles, Henry Baldwin Ward

Harold W. Manter Laboratory of Parasitology: Library Materials

For several years an interesting trematode has been under observation in the laboratory here. It occurs in various species of turtles, and was first discovered in some material shipped in from the south for class work. Peculiar importance attaches to the fact that it is a species inhabiting the circulatory system, and in fact it shows a relationship to the blood-inhabiting flukes of man which has become more clearly evident as the observations have accumulated. Since the material is easily obtained, it will afford perhaps the best opportunity available in this country for the laboratory study of forms adapted to …


Variation In Taraxacum, Paul B. Sears Feb 1921

Variation In Taraxacum, Paul B. Sears

Papers in Ecology

To the editor of Science: Since several species of Taraxacum are parthenogenetic and at the same time highly variable they have. looked like tempting material for the study of certain phases of genetics. Moreover their "polysnorphy," as well as that of other parthenogenetic plants, has served as a partial basis for well-known attempts to explain parthenogenesis as due to hybridization.


The Apple-Tree Tent Caterpillar, A. L. Quaintance Jan 1921

The Apple-Tree Tent Caterpillar, A. L. Quaintance

United States Department of Agriculture-Agricultural Research Service / University of Nebraska-Lincoln: Faculty Publications

The Apple-Tree Tent Caterpillar makes the unsightly nests or tents to be seen in the spring in trees along roadways, fences, and streams, and' in orchards. It varies greatly in abundance from year to year or over longer periods. Wild cherry is the favorite food plant, but many other plants are attacked, including several orchard fruits, especially the apple. During years when caterpillars are abundant the trees may be so completely stripped of their foliage that larvae are forced to hunt other food plants and hence are to be seen in numbers crawling over the ground and fences and elsewhere. …


The Relative Frequency Of Crossing Over In Microspore And In Megaspore Development In Maize, R. A. Emerson, C. B. Hutchison Jan 1921

The Relative Frequency Of Crossing Over In Microspore And In Megaspore Development In Maize, R. A. Emerson, C. B. Hutchison

Department of Agronomy and Horticulture: Faculty Publications

One of the early developments in the study of linkage in Drosophila was the discovery that the phenomenon of crossing over is confined to the female sex (Morgan 1912). The fact that no crossing over occurs in the male Drosophila holds true not only for sex-linked genes but for factors in the autosomes as well and is so well established that it affords a most convenient method of determining to which of the different linkage groups a new factor belongs.

The same phenomenon, but with the sexes reversed, obtains in the silkworm moth. Tanaka (1914, 1915) has found from back-cross …


Un Linguatulide Nouveau Parasite D’Un Batracien, Louis Gedoelst Jan 1921

Un Linguatulide Nouveau Parasite D’Un Batracien, Louis Gedoelst

Harold W. Manter Laboratory of Parasitology: Library Materials

Parmi des matériaux parasitqlogiques rec;us de l'Indian Museum de Calcutta et comprenant essentiellement des larves de dipteres, nous avons trouvé un objet d'un particulier intérêt, dont nous donnons la description ci-après.


Heritable Characters Of Maize: Ix. Crinkly Leaf, R. A. Emerson Jan 1921

Heritable Characters Of Maize: Ix. Crinkly Leaf, R. A. Emerson

Department of Agronomy and Horticulture: Faculty Publications

In 1910 a strain of dent corn obtained at the National Corn Exposition held at Omaha was crossed with a strain of flint corn obtained from the Department of Agronomy of the University of Nebraska. The F1 plants of this cross were normal and no abnormalities had been observed in the parent strains. But since the latter had not been subjected to self-pollination, there is no assurance that one or other of them did not have in it the character to be described here. In the F2 generation of this cross there occurred a tpe of plant that …


How To Select Good Layers, F. E. Mussehl Jul 1920

How To Select Good Layers, F. E. Mussehl

Nebraska Agricultural Experiment Station: Historical Circulars

Certain standard methods of selecting good laying hens have been developed as a result of observations made at the laying contests and at other places where trapnesting is being done.


Freezing Injury Of Seed Corn, Theodore A. Kiesselbach, J. A. Ratcliff Jun 1920

Freezing Injury Of Seed Corn, Theodore A. Kiesselbach, J. A. Ratcliff

University of Nebraska-Lincoln Extension: Historical Materials

Research Bulletin No. 16
The University of Nebraska Bulletin of the Agricultural Experiment Station of Nebraska

Summary • Introduction • Character of corn embryo and process of germination • Freezing injury not due to arrested development of the embryo • Moisture content of corn • Old corn • New corn • Physical effects of freezing • Ice formation in kernels • Effect of freezing on color of embryo • Effect of freezing on embryonic tissues • Chemical effects of freezing • Probable cause of death from freezing • Historical review • Crushing of plant tissues or rupturing of cell structures …


Freezing Injury Of Seed Corn, T. A. Kiesselbach, J. A. Ratcliff Jun 1920

Freezing Injury Of Seed Corn, T. A. Kiesselbach, J. A. Ratcliff

Nebraska Agricultural Experiment Station: Historical Research Bulletins

The object of the investigations in this bulletin has been to determine the conditions under which freezing injury may occur to seed corn; to indicate, if possible, the vital changes in the embryo resulting in such injury; and to point out ways by which seed corn of strong vitality and satisfactory yielding capacity may be obtained.


Albert Francis Coutant [Obituary] Jun 1920

Albert Francis Coutant [Obituary]

Harold W. Manter Laboratory of Parasitology: Library Materials

Obituary of Albert Francis Coutant, parasitologist. Born Brooklyn, New York, USA, July 7, 1892 - Died April 18, 1919, Manila, Philippine Islands.

Bibliograpy

Coutant, Albert F. 1915. The habits, life history and structure of a blood-sucking muscid larva (Protocalliphora azurea). Journal of Parasitology 1: 135-150.

Coutant, Albert F. 1916. Chenopodium poisoning: Report of case. Journal of the American Medical Association 67: 1,599-1,600.

Coutant, Albert F. 1918. An epidemic of influenza at Manila, P. I. Journal of the American Medical Association 71: 1,566-1,567.


Strawberries In Nebraska, C. C. Wiggans Feb 1920

Strawberries In Nebraska, C. C. Wiggans

Nebraska Agricultural Experiment Station: Historical Circulars

The strawberry is probably the most important small fruit grown in Nebraska. It thrives well in all sections of the State where the moisture supply is not too limited, being found almost universally in home plantings. It is also produced commercially in certain favored localities but this acreage is limited.


Heritable Characters Of Maize Ii.-Pistillate Flowered Maize Plants, R. A. Emerson Jan 1920

Heritable Characters Of Maize Ii.-Pistillate Flowered Maize Plants, R. A. Emerson

Department of Agronomy and Horticulture: Faculty Publications

In the "freak"

class at the Annual

Corn Show held at Lincoln, Nebraska,

in the winter of 1913-14,

there was exhibited a corn tassel

with a heavy setting of seeds. A few

seeds are not infrequently found in the

staminate inflorescence of maize, particularly

in pod com, and tillers of various

corn varieties often end in ears instead

of in tassels or have tassels, the central

spikes of which are ear like. The freak

exhibited at the com show, however,

was a large. much branched affair.

wholly tassel-like in form except for the

fact that it bore a heavy crop …


The Nebraska Tractor Law And Rules For Official Tractor Tests, L. W. Chase, E. E. Brackett, O. W. Sjogren, C. K. Shedd Dec 1919

The Nebraska Tractor Law And Rules For Official Tractor Tests, L. W. Chase, E. E. Brackett, O. W. Sjogren, C. K. Shedd

Nebraska Agricultural Experiment Station: Historical Circulars

The Nebraska Tractor Law, which became effective July 15, 1919, was enacted to encourage the manufacture and sale of improved types of tractors and to contribute to a more successful use of the tractor for farming. It was thought that the best method of accomplishing these objects would be to require a tractor of each model sold in the State to be tested at the State University and to have the results of these tests made public. These tests will give reliable information on the power, capacity and fuel consumption of each tractor and also some information on endurance. The …


Notes On North American Myxosporidia, Henry Baldwin Ward Dec 1919

Notes On North American Myxosporidia, Henry Baldwin Ward

Harold W. Manter Laboratory of Parasitology: Library Materials

In this paper are published data on three new species of Myxosporidia. Two species were observed in Lake Erie as parasites of a minnow; the third came from a species of Pacific salmon. Both cases present some unusual features that seem worthy of record.

Included are descriptions of Myxobolus aureatus nov. spec., Henneguya brachyura nov. sp., and Henneguya salminicola nov. spec.

I am greatly indebted to my colleague, Dr. Rokusaburo Kudo, for valuable assistance given while I was working up the material. The beautiful sketch illustrating the species from Lake Erie was prepared by Mrs. H. S. Jennings, to whom …