bluuebunny/crossref_metadata_2025 huggingface dataset:
Dynamics of Mechanical Systems and the Generalized Free-Body Diagram—Part I: General Formulation
Authors: Kövecses József
Published: August 2008

In this paper, we generalize the idea of the free-body diagram for analytical mechanics for representations of mechanical systems in configuration space. The configuration space is characterized locally by an Euclidean tangent space. A key element in this work relies on the relaxation of constraint conditions. A new set of steps is proposed to treat constrained systems. According to this, the analysis should be broken down to two levels: (1) the specification of a transformation via the relaxation of the constraints; this defines a subspace, the space of constrained motion; and (2) specification of conditions on the motion in the space of constrained motion. The formulation and analysis associated with the first step can be seen as the generalization of the idea of the free-body diagram. This formulation is worked out in detail in this paper. The complement of the space of constrained motion is the space of admissible motion. The parametrization of this second subspace is generally the task of the analyst. If the two subspaces are orthogonal then useful decoupling can be achieved in the dynamics formulation. Conditions are developed for this orthogonality. Based on this, the dynamic equations are developed for constrained and admissible motions. These are the dynamic equilibrium equations associated with the generalized free-body diagram. They are valid for a broad range of constrained systems, which can include, for example, bilaterally constrained systems, redundantly constrained systems, unilaterally constrained systems, and nonideal constraint realization.
Scratching of Elastic∕Plastic Materials With Hard Spherical Indenters
Authors: Flores Shane E. , Pontin Michael G. , Zok Frank W.
Published: August 2008

A mechanistic framework has been developed for interpreting scratch tests performed with spherical indenters on elastic∕plastic materials. The pertinent scaling relations have been identified through a plastic analysis and the model has been subsequently calibrated by finite element calculations. The results show that the ratio of scratch force to normal force (or apparent friction coefficient) can be partitioned into two additive components: one due to interfacial friction and another associated with plastic deformation. The plastic component scales parabolically with the normal force and depends only weakly on the true (elastic) friction coefficient. A simple formula for the scratch force, based on the plastic analysis and the numerical results, has been derived. Finally, experimental measurements on two material standards commonly used for nanoindenter calibration have been used to verify the theoretical results.
High-Quality Binary Protein Interaction Map of the Yeast Interactome Network
Authors: Yu Haiyuan , Braun Pascal , Yıldırım Muhammed A. , Lemmens Irma , Venkatesan Kavitha , Sahalie Julie , Hirozane-Kishikawa Tomoko , Gebreab Fana , Li Na , Simonis Nicolas , Hao Tong , Rual Jean-François , Dricot Amélie , Vazquez Alexei , Murray Ryan R. , Simon Christophe , Tardivo Leah , Tam Stanley , Svrzikapa Nenad , Fan Changyu , de Smet Anne-Sophie , Motyl Adriana , Hudson Michael E. , Park Juyong , Xin Xiaofeng , Cusick Michael E. , Moore Troy , Boone Charlie , Snyder Michael , Roth Frederick P. , Barabási Albert-László , Tavernier Jan , Hill David E. , Vidal Marc
Published: August 2008

Current yeast interactome network maps contain several hundred molecular complexes with limited and somewhat controversial representation of direct binary interactions. We carried out a comparative quality assessment of current yeast interactome data sets, demonstrating that high-throughput yeast two-hybrid (Y2H) screening provides high-quality binary interaction information. Because a large fraction of the yeast binary interactome remains to be mapped, we developed an empirically controlled mapping framework to produce a “second-generation” high-quality, high-throughput Y2H data set covering ∼20% of all yeast binary interactions. Both Y2H and affinity purification followed by mass spectrometry (AP/MS) data are of equally high quality but of a fundamentally different and complementary nature, resulting in networks with different topological and biological properties. Compared to co-complex interactome models, this binary map is enriched for transient signaling interactions and intercomplex connections with a highly significant clustering between essential proteins. Rather than correlating with essentiality, protein connectivity correlates with genetic pleiotropy.
Quantum Communication with Zero-Capacity Channels
Authors: Smith Graeme , Yard Jon
Published: August 2008

Communication over a noisy quantum channel introduces errors in the transmission that must be corrected. A fundamental bound on quantum error correction is the quantum capacity, which quantifies the amount of quantum data that can be protected. We show theoretically that two quantum channels, each with a transmission capacity of zero, can have a nonzero capacity when used together. This unveils a rich structure in the theory of quantum communications, implying that the quantum capacity does not completely specify a channel's ability to transmit quantum information.
Experimental muscle pain during a forward lunge — the effects on knee joint dynamics and electromyographic activity
Authors: Henriksen M , Alkjær T , Simonsen E B , Bliddal H
Published: August 2008

Objective:

The purpose of this study was to investigate whether the knee joint dynamics during a forward lunge could be modulated by experimentally induced vastus medialis pain in healthy subjects.

Design:

Randomised cross-over study.

Setting:

Biomechanical movement laboratory.

Participants:

20 healthy subjects were included. One subject was excluded during data collection.

Intervention:

The subjects performed forward lunges before, during and 20 minutes after induction of experimental quadriceps muscle pain. Muscle pain was induced using hypertonic saline (5.8%) injected intramuscularly. Isotonic saline (0.9%) was used as control.

Main outcome measurements:

Three-dimensional movement analyses were performed and inverse dynamics were used to calculate joint kinematics and kinetics for ankle, knee and hip joints. Electromyographic (EMG) signals of the hamstrings and quadriceps muscles were recorded.

Results:

During and after pain, significant decreases in knee joint dynamics and EMG recordings were observed.

Conclusion:

The study shows that local pain in the quadriceps is capable of modulating movements with high knee joint dynamics. The results may have implications in the management of muscle pain and prevention of injuries during activities involving the knee joint.
Cost-effectiveness of the Australian National Tobacco Campaign
Authors: Hurley S F , Matthews J P
Published: August 2008

Background:

The Australian National Tobacco Campaign (NTC) was an intensive mass media anti-smoking campaign, the first phase of which commenced in 1997, cost around $A9 million, and reduced smoking prevalence by 1.4%.

Objective:

To assess the cost-effectiveness of phase one of the NTC, which ran from June to November 1997.

Design and study population:

The quit benefits model (QBM), a Markov-cycle simulation model was used to predict the benefits of smoking cessation for the estimated 190 000 quitters from the time of quitting until death, censored at age 85 years. Measures of effectiveness were cases of lung cancer, acute myocardial infarction (AMI), stroke and chronic obstructive pulmonary disease (COPD) avoided; deaths prevented, and life-years and quality-adjusted life-years (QALYs) gained. The savings in healthcare costs through prevention of the four specified smoking-associated diseases were estimated. Future costs, life-years and QALYS were discounted at 3% per year.

Results:

The QBM predicted that the NTC avoided over 32 000 cases of COPD, 11 000 cases of AMI, 10 000 cases of lung cancer, and 2500 cases of stroke. Prevention of around 55 000 deaths, gains of 323 000 life-years and 407 000 QALYs, and healthcare cost savings of $A740.6 million were predicted. The NTC was therefore both cost saving and effective.

Conclusions:

As well as reducing smoking prevalence, the NTC was unequivocally cost-effective.
THE GROWTH CYCLE OF THE BLUEBERRY AND SOME FACTORS OF THE ENVIRONMENT
Authors: Bell Hugh P.
Published: August 2008

The effects of latitude, burning, and pruning on the growth cycle of the blueberry were studied and found to be as follows. The morphology of the growth cycle and the sequence of morphological changes were not altered by any of the factors considered. For spring and summer, a north and south difference of one hundred and fifty miles had no greater effect than that which is regarded as "seasonal". Burning and pruning delayed the spring and summer growth by about two weeks. For the late autumn and early winter, there was some evidence that morphological changes occurred in the distal florets during that period, but for the "depth of winter", that is from mid-December till the end of February, the winter bud was a morphological complex that, with the exception of the apical floret, always had the same structure regardless of latitude, burning, or pruning and this structure was the same as that found in normal plants during that season.
AN ESSENTIAL BACTERIAL GROWTH FACTOR PRODUCED BY MICROBIAL SYNTHESIS
Authors: Lochhead A. G. , Burton Margaret O.
Published: August 2008

An organism isolated from soil, cultivated in a simple medium containing only inorganic salts and sugar, was found to synthesize an essential growth factor that was nutritionally equivalent to soil extract in promoting the growth of an organism for which the latter was hitherto considered essential. The factor could not be replaced by the B vitamins, purines, pyrimidines, or other growth-promoting substances tested (including derivatives of various natural products) with the exception of hemin, which evoked but a partial response, and concentrated liver extract, the effect of which was not attributable to vitamin B12. Partially purified material from the metabolic liquid showed distinct growth-promoting activity at a concentration of 0.1 p.p.m. The organism requiring the growth factor, as well as that synthesizing it, both pleomorphic bacteria of the "soil diphtheroid" type, were found to be hitherto undescribed species. They are considered to be most appropriately assigned to the genus Arthrobacter, as proposed by Conn and Dimmick, and are named, respectively, Arthrobacter terregens n. sp. and Arthrobacter pascens n. sp.
THE RESPONSE OF POTATO TUBERS TO A PERIOD OF ANAEROBIOSIS: I. DRIFTS IN CARBON DIOXIDE PRODUCTION
Authors: Forward Dorothy F.
Published: August 2008

A survey of the course of carbon dioxide output of potato tubers upon transfer from air to nitrogen shows that the form of drift in nitrogen undergoes metamorphosis with the lapse of time between harvest and the anaerobic experience. A stable form is attained about three months from harvest.On restoration of air after nitrogen a temporary outburst of carbon dioxide occurs, and both form and magnitude of this after-effect change with time elapsed after harvest. The magnitude is also influenced by the duration of anaerobiosis. At any season, increased time in nitrogen produces an increased after-effect of more than proportionate magnitude. The rate of carbon dioxide output in air after nitrogen ultimately becomes steady, but is not necessarily equivalent to that preceding anaerobiosis. For the space of about three months, subjecting a tuber to nitrogen for two days or more at 22 °C. causes the ultimate rate of carbon dioxide output in air to remain well above that preceding anaerobiosis, while it bears a constant ratio to the final rate in nitrogen before air was restored. This permanent displacement of the rate in air is not at any time brought about by an anaerobic period of only one day.The nature of the drifts in metabolic state of the tubers that underlie these metamorphic changes in response to a period of anaerobiosis is still under investigation.
THE ISOLATION AND IDENTIFICATION OF SUCROSE FROM THE SEEDLING WHEAT LEAF
Authors: Ward G. M.
Published: August 2008

Crystalline sucrose has been isolated from cleared alcoholic extracts of mature wheat leaves by precipitation as the barium salt. The crystals were positively identified by melting point, X-ray diffraction analysis, and glucose–fructose ratio as well as by conventional analytical techniques. The evidence for the presence of sucrose in the wheat leaf has been corroborated by chromatographic analysis of leaf extracts. It is concluded that sucrose forms the bulk of the soluble sugar reserve of this tissue.
MICROBIOLOGICAL STUDIES OF AIR OVER SOME NONARCTIC REGIONS OF CANADA
Authors: Kelly C. D. , Pady S. M.
Published: August 2008

Using aircraft, studies were carried out on the numbers of bacteria and fungi in the air and 10 separate flights were made during 1948 and 1949 covering territory between Goose Bay, Labrador, and Fairbanks, Alaska. Quantitative samples were taken on agar plates, and silicone coated slides in the McGill G.E. Sampler, as well as in glass wool filters and the results correlated with definite air masses. A comparison of methods showed that the McGill G.E. Sampler gives higher and more consistent results for the total viable count than the filters. Silicone coated slides give the total fungus count including nonviable spores and spores that will not grow on the agar plates.From various air masses and during different times of the year, there was considerable variation in the average number of bacteria and fungi found. The highest fungus count was 23.6 per cu. ft. and the lowest 0.01. There was less variation in the number of bacteria, the highest being 5.6 and the lowest 0.2 per cubic foot. The highest fungus counts were found in continental polar air during the summer months while for the bacteria the highest counts were found in Pacific polar air during the spring and fall. The bacteria and fungi isolated were all soil types.
FERTILITY AND POLYPLOIDY OF EUPHORBIA CYPARISSIAS IN CANADA
Authors: Moore R. J. , Lindsay D. R.
Published: August 2008

Euphorbia cyparissias L., a European species originally introduced into North America as an ornamental, is now firmly established on roadsides and pastures in Eastern Canada. The Canadian distribution is mapped from specimens in three herbaria. Plants with a somatic chromosome number of 20 and plants with the number 2n = 40 occur in eastern Ontario and adjacent Quebec. According to all available evidence for this region, the diploid plants never set seed, whereas the tetraploid populations are highly fertile. The cells of the upper leaf epidermis of the tetraploid plants are conspicuously larger than those of the diploid plants. By means of this criterion, the probable chromosome number of herbarium specimens was determined. The distribution of the diploid and tetraploid plants in Ontario and western Quebec is mapped. Tetraploid plants are known from eight locations in this area; five of these infestations are serious. It is believed that the sterility of the diploid populations is due to a genic condition which may interrupt normal pollen development.
MICROBIOLOGICAL STUDIES OF THE ACTION OF SOME SELECTED SOIL FUMIGANTS
Authors: Wensley R. N.
Published: August 2008

Microbiological studies involving the use of three soil fumigants, methyl bromide, a propane–propene mixture, and ethylene dibromide, established a biological basis for the evaluation of soil fumigants as fungicides, bactericides, and actinomycides and provided quantitative and qualitative data from which the efficacy of each fumigant was rated as high, medium, low, and poor in each capacity and permitted a study of the significance of population trends. Due emphasis was placed on the two factors, concentration of the fumigant and the period of confined exposure, by determining the value of each factor required to produce, under controlled conditions of temperature and soil moisture, a 90% reduction in numbers of each microbiological group. Methyl bromide proved to be the most effective fumigant in all three capacities while ethylene dibromide formulations were least effective. The concentrations of, and exposure periods to, ethylene dibromide and the propane–propene mixture required to give satisfactory reduction of the three microbiological populations are considered high and neither fumigant is recommended as a fungicide, bactericide, or actinomycide. However, ethylene dibromide proved to be more effective than methyl bromide against root-knot nematodes and is recommended for use in this capacity. Soil fumigation effectively altered the microbiological balance in favor of fungi that were normally suppressed by a predominance of aspergilli and penicillia. Of four physiological groups of bacteria studied, nitrifiers and cellulose decomposers were most severely reduced in numbers by methyl bromide fumigation. The actinomycetes showed a greater tolerance of fumigation than either the fungi or bacteria.
ANTAGONISME DES MICROORGANISMES DU SOL ENVERS FUSARIUM OXYSPORUM F. LINI, AGENT DE LA FLÉTRISSURE DU LIN
Authors: Lachance Par René-O. , Perrault C.
Published: August 2008

Nineteen bacteria and 11 actinomycetes isolated from various soils in which fiber flax had been grown in the Lower St. Lawrence district were found to be antagonistic to Fusarium oxysporum f. lini. Among the 11 organisms forming the largest inhibition zone on agar plates, six had a fungicidal action on the spores of F. oxysporum f. lini while the other five exerted a fungistatic action. Among the 19 antagonistic bacteria under trial, six induced a swelling of the germ tubes or the production of an appressoriumlike structure on agar. Green-house experiments have indicated that 15 bacteria and 11 actinomycetes offered a certain protection to seedlings some of which reached. 6, 12, and sometimes 24 in. in height before showing any signs of uniting. The organisms evidently delayed the onset of wilt symptoms, but failed to protect the plants through their entire growth.
CYTOLOGICAL STUDIES OF CHROMOSOMES OF RUST FUNGI: I. THE MITOTIC GHROMOSOMES OF PUCCINIA GRAMINIS
Authors: McGinnis R. C.
Published: August 2008

Germinating sporidia (basidiospores) of Puccinia graminis Pers. were cytologically examined during nuclear division (mitosis) to determine the chromosome number. Studies at metaphase showed a haploid number of six chromosomes for this organism. Prophase chromosomes were observed to be united to form a continuous chain. Limits of individual chromosomes could not be seen at this stage. At metaphase, what were apparently residual terminal attractions were observed, the six chromosomes appearing as three loose pairs. The possibility of a basic chromosome number of three for this species is discussed.
NOTES ON BOREAL USTILAGINALES
Authors: Savile D. B. O.
Published: August 2008

A number of new records of smut fungi, largely from northern Canada, are listed. Thecaphora apicis (on Carex pyrenaica), Ustilago cilinodis (on Polygonum cilinode), and U. anomala Kunze var. tovarae (on Polygonum virginianum) are described as new. Ustilago punctata Clint. is shown to be synonymous with U. bosniaca G. Beck. Ustilago polygoni-punctati nom. nov. is proposed in place of the invalid name U. microspora (Speg.) Liro. Ustilago anomala Kunze var. cordai (Liro) Savile and U. violacea (Pers.) Roussel var. stellariae (Sow.) Savile are proposed as new combinations.
STUDIES IN FOREST PATHOLOGY: XI. DECAY IN BLACK COTTONWOOD IN THE MIDDLE FRASER REGION, BRITISH COLUMBIA
Authors: Thomas G. P. , Podmore D. G.
Published: August 2008

A study of decay of black cotton wood, Populus trichocarpa Torr. and Gray, revealed that, although 70 species of fungi caused decay, only six caused significant loss in living trees and that two of these, Polyporus delectans Peck and Pholiota destruens (Brand.) Quél., caused 92% of this loss. The sporophores and associated decays of certain of the fungi are described and their relative importance is indicated. Data on the relation of decay to tree age showed that, despite a high incidence of infection, the average volume of decay per infected tree was low. In general, decay proved important only to the recovery of specialty products such as plywood. A significant reduction of strength was found to occur in wood containing an early stage of decay caused by P. destruens. The practicability of segregating trees having a high or low probability of being decayed was demonstrated through the use of decay indicators.
BACTERIOPHAGE IN RELATION TO XANTHOMONAS TRANSLUCENS
Authors: Katznelson H. , Sutton M. D.
Published: August 2008

A phage specific for one isolate of Xanthomonas translucens f. sp. undulosa and three polyvirulent phages active against various members of the X. translucens group have been isolated. One of the polyvirulent phages, Pg35, lysed 24 out of 28 isolates of X. translucens; the other two were somewhat less active. Attempts to use form specific phages to identify cultures of X. translucens f. spp. hordei, hordei-avenae, and undulosa were unsuccessful. However, use of a phage specific for f. sp. secalis to detect homologous cultures gave encouraging results.
PRELIMINARY STUDIE IN ASCOCHYTA PISI LIB.
Authors: Brewer Donald , MacNeill Blair H.
Published: August 2008

Foliage infection of pea by Ascochyta pisi Lib. is accomplished by direct penetration of the cuticle without the formation of an appressorium. Subsequent colonization is at first subcuticular, then intercellular, resulting in the collapse and death of the host cells. No haustoria are formed. Resistance may be due in part to the cuticular barrier as well as to a physiologic factor which limits the colonization of the host once penetration has been effected. Pycnidial formation is symphogenous. Spores are produced singly from conidiophores that grow out from the inner wall cells of the pycnidium. Each spore is two-celled, and each cell contains but one nucleus. A single nuclear division occurs early in the ontogeny of the spore so that most spores even prior to germination have binucleate cells. Spore production is marked by the almost complete depletion of the protoplasmic content of the fungal mass; as a consequence vegetative development of the mycelium ceases and the focus of infection becomes localized as a leaf spot. It is suggested that the production of this discrete type of lesion by A. pisi and certain other pycnidiaceous leaf-spotting fungi is, mainly, a function of the developmental rhythm of the fungus, and, accordingly, is not the expression of a specific host-parasite interaction.
PYRENOMYCETES OF BRITISH COLUMBIA
Authors: Barr Margaret E.
Published: August 2008

The 258 species and six varieties listed from the province are distributed in 94 genera as follows: Perisporiales — 28 species and three varieties in 14 genera; Hypocreales — 19 species in 10 genera; Sphaeriales — 205 species and three varieties in 65 genera; Dothideales — six species in five genera.
THE PERSISTENCE OF THIRAM IN SOIL AND ITS RELATIONSHIP TO THE MICROBIOLOGICAL BALANCE AND DAMPING-OFF CONTROL
Authors: Richardson L. T.
Published: August 2008

A means of determining the thiram content of treated soil was developed, applying the paper disk bioassay technique with Glomerella cingulata as the test organism. It was found that thiram persisted in sandy soil for over two months but disappeared from compost soil within one week. Thiram treatment changed the microbiological balance in the soil, the number of bacteria being increased and the fungi decreased for some time. Thiram was shown to be selective in its action against fungi; Penicillium and Trichoderma, being resistant, increased in number after soil treatment. Thiram treatment rendered soil more difficult to infest artificially with Pythium ultimum and also prevented a natural increase in the population of damping-off organisms resulting from repeated cropping. This protection for seedlings persisted longer than did the fungicide in the soil.
STUDIES IN PLANT MINERAL NUTRITION: I. AN INVESTIGATION INTO THE CAUSE OF GRAY SPECK DISEASE OF OATS
Authors: Leach W. , Bulman Ruth , Kroeker Johanna
Published: August 2008

A series of experiments were carried out over a period of three years in which plants of Avena sativa var. Tama were grown in nutrient solutions which provided variations in iron and manganese concentrations, calcium concentration, and pH. The experiments were conducted under a wide range of growing conditions as regards light intensity and temperature control. The aim of the work was to furnish information regarding the factors associated with the development of the symptoms of gray speck disease. The experimental results indicated that under otherwise favorable culture conditions, manganese deficiency alone will produce gray speck symptoms. Inoculation of the cultures with root material from plants bearing gray speck symptoms had no effect whatever on the incidence of the disease. Variations in the pH of the culture solutions did not affect the development of gray speck symptoms, but the symptoms appeared later in cultures containing a high concentration of calcium than in cultures containing a low concentration of this metal.
STUDIES ON ACTINOPHAGE FOR STREPTOMYCES SCABIES (THAXT.) WAKSMAN AND HENRICI
Authors: Newbould F. H. S. , Garrard E. H.
Published: August 2008

An actinophage for Streptomyces scabies was isolated from soil surrounding scab infected potatoes. Tested against 15 scab producing Streptomyces cultures isolated from scab lesions, 13 were lysed, one partially lysed, and one was resistant. Against 15 nonscab producing strains of actinomycetes, also isolated from scab lesions, 13 were not lysed and 2 showed evidence of partial lysis. Tested against actinomycete cultures isolated from soil, the phage was less specific and the results were inconclusive. Lack of phage specificity is attributed to variation among Streptomyces cultures.
RING WIDTH, TRACHEID SIZE, AND RAY VOLUME IN STEM WOOD OF THUJA OCCIDENTALIS L.
Authors: Bannan M. W.
Published: August 2008

The interrelations between varied growth rates and those phases of cambial activity involved in determination of tracheid size and ray volume were investigated in Thuja occidentalis. Length of tracheids at the time of pseudotransverse division of the initiating cambial cells was determined from the peripheral wood of stems which fell within a similar range of size but differed in their rates of growth. The circumstances which favored accelerated growth, as shown in more frequent periclinal divisions in the cambium, encouraged earlier pseudotransverse division of fusiform initials and hence the production of shorter tracheids. Among trees of similar size decline in growth rate was accompanied by lengthening of cambial cells to a maximum associated with annual radial increments of 0.7 to 0.8 mm. Tracheid diameter was only slightly influenced by the rate of growth. Tangential width underwent minor increase in suppressed trees and radial diameter was slightly augmented in fast-growing trees. A positive correlation was revealed between ray volume and rate of growth.
A CONTRIBUTION TO THE CONCEPT OF WOUND REPAIR IN WOODY STEMS
Authors: Barker W. George
Published: August 2008

Those xylem ray cells closely associated with the cambial zone will unite in proliferating with other cells recently derived from the cambium following the wounding of a basswood stem. However, ray cells remote from the cambium, although potentially meristematic, will fail to divide. Nonetheless these latter will grow out occasionally when the ray, exposed during the culturing operation, is closely connected with actively growing callus tissue. Parenchyma throughout the body of the secondary wood of the basswood has been shown to proliferate whenever a mass is exposed which is considerably larger in volume than a normal multiseriate ray. The healing of wounds in the linden best should be considered as a function of active, newly formed, cambial derivatives and not as a reaction dominated by any one tissue.
AN ANATOMICAL STUDY OF CANE AND GROWN GALLS
Authors: McKeen W. E.
Published: August 2008

An anatomical study was made of galls which occur naturally on the stems of boysenberry and Himalaya blackberry plants. The galls form at any region of the stem of the floral canes of plants systemically infected with Agrobacterium rubi and originate from or near the cambial layer, and not from the outer layer of the pericycle. The vascular system in galls caused by A. rubi and A. tumefaciens on broad bean, tomato, sugar beet, loganberry, and Himalaya blackberry plants is connected to the vascular system of the organ on which they are growing.
CYTOLOGICAL STUDIES IN ALFALFA POLYPLOIDS
Authors: Armstrong J. M.
Published: August 2008

Normal tetraploid alfalfa, Medicago sativa L., is characterized by meiotic irregularities consisting of a low percentage of univalents, trivalents, and quadrivalents. While these irregularities might suggest an autoploid origin, their frequency is too low to be conclusive. Cytological studies of the induced octoploid and of the hexaploid, obtained from crossing tetraploid and octoploid, indicate that the two genomes in the tetraploid are only partially homologous. The partial homology is established by the meiotic behavior in the hexaploid in which a low univalent frequency indicates fairly complete pairing between the A and B genomes. The comparatively low frequency of quadrivalents in the octoploid indicates a correspondingly low chiasma frequency at pachytene. Nevertheless this quadrivalent frequency in the octoploid is more than three times as high as in the tetraploid which suggests a lack of complete homology between the two genomes. The theory is advanced that tetraploid species of Medicago originated from crosses between a series of diploid species fairly similar cytologically but differing in well marked, morphological characters. This affords an explanation for the inheritance of some characters in a disomic and others in a tetrasomic manner. Cytological and genetic evidence thus points to tetraploid alfalfa as originating as an alloploid from closely related diploid species.
A HITHERTO UNREPORTED ASCOMYCETE PARASITIC ON THE ROOTS OF WHEAT, OATS, AND BARLEY
Authors: Robinson D. B. , Ayers G. W.
Published: August 2008

An ascomycetous fungus, named Cryptoascus graminis sp. nov., is described. This fungus is found parasitic on the roots of wheat, oats, and barley in Prince Edward Island.
STUDIES IN PLANT MINERAL NUTRITION: II. THE ABSORPTION OF IRON AND MANGANESE BY DWARF KIDNEY BEAN, TOMATO, AND ONION FROM CULTURE SOLUTIONS
Authors: Leach W. , Taper C. D.
Published: August 2008

Dwarf kidney beans and tomatoes were grown in complete nutrient solutions containing various concentrations of iron and manganese. It was found that the iron to manganese ratio in the culture solutions must be within a definite range in order to avoid deficiency symptoms in the experimental plants. For the dwarf bean this range was 1.5 to 3.0, and for the tomato it was 0.5 to 5.0. Concentration ratios outside the optimum range produced either iron or manganese deficiency symptoms. Concentrations below minimum values of both iron and manganese always produced deficiency symptoms irrespective of the ratio of iron to manganese in the culture solutions. An apparent antagonism between the absorption of iron and of manganese was observed with both beans and tomatoes grown in nutrient solutions. This antagonism was also found to occur with onions grown in solutions containing only the sulphates of the two metals. It was further found that with onions growing in single salt solutions of the sulphates of iron and manganese, the concentration of iron or manganese in the solutions did not affect the amounts of the metals absorbed by the plants from the solutions. The combined amount of iron plus manganese absorbed appeared to remain constant irrespective of the iron to manganese ratio in the culture solution.
THE EFFECT OF INFECTION BY HELMINTHOSPORIUM SATIVUM ON THE AMINO ACID CONTENT OF WHEAT ROOTS
Authors: Hrushovhtz S. B.
Published: August 2008

The amino acids present in roots of healthy and diseased (Helminthosporium sativum P. K. & B.) wheat seedlings were determined by paper chromatography. Treatment of dried roots with 80% ethanol followed by acid hydrolysis effected maximum extraction of the amino acids. Eleven free and 13 combined amino acids were identified on the chromatograms, and four unidentified fractions were indicated. Total nitrogen of the diseased roots was higher on a dry weight basis than that of healthy roots. The aggregate content of both free and combined amino acids was slightly higher in the diseased roots than in the healthy ones. However, the concentrations of free alanine, serine, and asparagine in the diseased roots were twice those in the healthy ones.
THE OCCURRENCE OF FUSARIUM SPECIES IN CANADA: III. TAXONOMY OF FUSARIUM SPECIES IN THE SEED OF VEGETABLE, FORAGE, AND MISCELLANEOUS CROPS
Authors: Gordon W. L.
Published: August 2008

A taxonomic study was made of isolates of Fusarium obtained from a microbiological examination of seed from a total of 44 species and botanical varieties of cultivated plants. These plants may be classed as vegetable, forage, and miscellaneous crops. Most of the seed samples originated from stocks produced in Canada, but some were seed from other countries. A total of 16 species, varieties, and forms of Fusarium, classified in eight sections of the genus, were encountered among the isolates that were obtained from seed; they are F. poae (Pk.) Wr., F. sporotrichioides Sherb., F. arthrosporioides Sherb., F. avenaceum (Fr.) Sacc, F. semitectum Berk. & Rav., F. acuminatum Ell. & Ev., F. compactum (Wr.) Gordon, F. equiseti (Cda.) Sacc, F. culmorum (W. G. Sm.) Sacc, F. graminearum Schwabe, F. sambucinum Fuckel, F. sambucinum var. coeruleum Wr., F. moniliforme Sheld. em. S. & H., F. oxysporum Schlecht. em. S. & H., F. oxysporum f. lini (Bolley) S. & H., F. solani (Mart.) App. & Wr. em. S. & H. From the seed of a total of 44 species and botanical varieties of host plants, F. equiseti was identified among isolates from 34; F. poae and F. oxysporum each from 18; F. acuminatum from 17; F. avenaceum from 16; F. culmorum, from 10; F. sambucinum and F. moniliforme each from five; F. graminearum and F. sambucinum var. coeruleum each from four; F. solani from three; F. sporotrichioides from two; F. arthrosporioides, F. semitectum, F. compactum, and F. oxysporum f. lini each from one. The origin of the seed samples of each host is given.
MICROBIOLOGICAL STUDIES OF AIR MASSES OVER MONTREAL DURING 1950 AND 1951
Authors: Kelly C. D. , Pady S. M.
Published: August 2008

The numbers of bacteria and fungi in air masses over Montreal, Canada, were determined by sampling at the top of the Sun Life Building, 400 ft. above ground level, from September 1950 to December 1951. During 113 days of sampling, 978 exposures were made with agar plates in the General Electric Bacterial Air Sampler and the Bourdillon Slit Sampler. Eighty-seven exposures for fungus spores were made with silicone coated slides in the Slit Sampler. Most of the air encountered was continental polar either moving direct to Montreal, found on 38 days, or modified by moving over agricultural land, sampled on 51 days. Maritime polar air from the Atlantic was encountered on 21 days, and from the Pacific on one day. Maritime tropic air from the Gulf of Mexico was encountered twice. The seasonal variation of bacteria and fungi in all air masses showed low counts in January, February, and March. Higher bacterial counts were obtained from early April into July and from early September into November, covering a range from 3.0 to 55.0 per cu. ft. Lower counts were found during late July and August. The high fungus counts extended from May into November and covered a range from 5.0 to 56.3 per cu. ft. Both continental polar and maritime polar air that moved over considerable cultivated land showed generally higher counts than where these air masses moved directly to Montreal.
STUDIES IN FOREST PATHOLOGY: XIV. DECAY OF DOUGLAS FIR IN THE COASTAL REGION OF BRITISH COLUMBIA
Authors: Thomas G. P. , Thomas R. W.
Published: August 2008

An investigation of Douglas fir, Pseudotsuga taxifolia (Poir.) Britton, in coastal British Columbia has shown that decay losses in old-growth stands are low, amounting to 2.6 and 7.3% of the gross volume of living and combined living and dead trees respectively. Twenty-five decay-producing fungi were isolated from living trees and 29 from dead trees. The most important of these were Fomes pini (Thore) Lloyd, Polyporus schweinitzii Fries, and Fomes pinicola (Sw.) Cke. Certain irregularities in the occurrence of decay-producing fungi and the amounts of decay associated with them were traced to the influences of site, tree age or size, latitude, and stand history. Root infections were the most frequent but branch-stub infections caused the greatest average amount of decay. An examination of tree abnormalities showed that a select group of them, sporophores and swollen knots of Fomes pini in particular, are useful indicators of hidden decay. A separate analysis of dead trees has shown that they occasion ally form a high proportion of Douglas fir stands and that much of the wood in such trees is sound.
SEED DEVELOPMENT IN BLACKBERRIES
Authors: Kerr Ernest A.
Published: August 2008

This study of blackberries deals with seed production and germination, describes the main steps in megagametophyte development of pseudogamous and syngamous varieties, and traces the development of both germinable and aborted seeds. Certain conclusions are drawn concerning the interdependence of maternal and filial tissues. The number of drupelets which develop in both pseudogamous and syngamous varieties depends, in part, on the pollen parent. A small but rather constant proportion of the drupelets display only a partial enlargement. Seeds of the well-developed drupelets are divided into three intergrading classes: (i) plump seeds, (ii) collapsed seeds, and (iii) an intermediate group. The general developmental features of the ovule and its contents are described. Regular megagametophyte formation is the rule in the syngamous varieties, but many irregularities, especially multiple gametophytes, are common in the pseudogamous species studied. Approximately a third of the seeds in the drupelets which appeared normal at 6 to 15 days after pollination did not contain an embryo. Some of the "eggs" were disintegrating, whereas others were still in a turgid condition. All the seeds which were imperfectly developed contained endosperm but only rarely was there an embryo or its remains. Reserve food was usually stored only in the chalazal region of the endosperm. The endosperm is believed to stimulate the transfer of nutrient materials to the seed. The embryo supplements this function as the seed approaches maturity, and influences the distribution of the storage products within the endosperm.
QUANTITATIVE STUDIES ON THE SURVIVAL OF FUNGI IN FIVE-YEAR-OLD DRIED SOIL CULTURES
Authors: Atkinson R. G.
Published: August 2008

Of 51 dried soil cultures of fungi isolated from soil, only 12, comprising seven of the 32 genera represented, were viable after five years. Platings, directly from the cultures, of 5-, 50-, and 500-mgm. samples with oxgall-amended potato dextrose agar revealed extreme variations in viability of surviving fungi. Population levels were so high in cultures of Rhizopus nigricans, Aspergillus fumigatus, A. sydowi, and A. ustus that plate counts were not obtained, even when a 5-mgm. sample was apportioned among five plates. Cultures of Chaetomium indicum and of C. spirale contained an estimated population of approximately one and one half million, and 450,000 viable centers per gram, respectively, the highest counts obtained. The next most viable cultures were those of Fusarium oxysporum var. redolens and of Circinella spinosa, but these contained only about 60,000 and 20,000 centers per gram, respectively. Next came Penicillium janthinellum with an estimated 4000 centers per gram. The least viable cultures were those of Penicillium purpurogenum and of two isolates of F. oxysporum whose population level was down to about 100 to 200 viable centers per gram.
THE ANTIBIOTIC ACTIVITY OF SOIL MICROORGANISMS AS RELATED TO BACTERIAL PLANT PATHOGENS
Authors: Patrick Z. A.
Published: August 2008

In an attempted evaluation of the importance of soil antagonisms as a possible factor in the different survival capabilities of some bacterial plant pathogens in the soil environment, a comparison was made of the numbers of antagonists detected when different plant pathogenic species were used as test organisms in determining the "antibiotic potential" of nine "virgin" soils. It was found that there are present among the soil flora a great abundance of microorganisms intrinsically capable of antagonizing most of the bacterial pathogens tested and only for a few species are such antagonists relatively rare. There were great differences in the number of isolates antagonistic to the different pathogenic species, even in the same genus, and there seemed to be a correlation between the numbers of antagonists, as found here, and the capability of a species to maintain itself for long periods in the soil. For the most part the Xanthomonas species appeared to be most sensitive to the antagonistic soil microflora while the soft-rot-causing Erwinia species were most resistant.A comparative study of the antibiotic activity of 120 of the most active antagonistic isolates tested against 28 bacterial plant pathogens showed that each antagonist was characterized by a specific antibacterial spectrum and those antagonists having the most intense antibiotic activity usually inhibited the greatest number of bacterial species. Many antagonists were highly specific, affecting only certain groups or even certain species. The high specificity which characterized some of the antibiotic reactions was used to separate sharply, consistently, and with minimum effort such closely related species as E. carotovora and E. atroseptica or X. corylina and X. juglandis.
THE PHYSIOLOGY OF STOMATA: I. CARBON DIOXIDE FIXATION IN GUARD CELLS
Authors: Shaw Michael , Maclachlan G. A.
Published: August 2008

The guard cells of Tulipa gesneriana L. were found to contain both chlorophylls a and b. The total chlorophyll content was estimated to be of the order of 0.5 × 10−12 gm, per cell. By exposure to radioactive carbon dioxide followed by microautoradiography, selective carbon dioxide uptake in the light was demonstrated in the stomatal cells of Allium, Hordeum, Nicotiana, Sedum, Tradescantia, Tulipa, and Vicia, A less intense uptake was observed in darkness with Allium, Sedum, Tulipa, and Vicia. The rate of guard-cell photosynthesis was estimated to be of the order of 0.02 × 10−12 M. carbon dioxide per cell per hour at 500 ft-c. and in 0.04% (v/v) carbon dioxide. It was concluded that this rate was too low to account for the increase in osmotic potential caused by illumination.
THE PRODUCTION OF THIAMINE BY CERCOSPORA CRUENTA SACC.
Authors: Naqvi S. H. Zamin
Published: August 2008

Cercospora cruenta Sacc, the causal organism of a leaf spot of Vigna catjang Endl., was investigated with respect to (1) its ability to synthesize thiamine, (2) the presence of thiamine in its mycelium, and (3) possible release of thiamine from the mycelium into the medium. The fungus was found to synthesize thiamine from a medium containing inorganic salts and dextrose. The thiamine was found chiefly stored in the mycelium with only a trace in medium in which the fungus had grown for 50 days at 25 °C.
CULTURE OF PRASIOLA STIPITATA SUHR
Authors: Lewin Ralph A.
Published: August 2008

Prasiola stipitata has been grown from spore to maturity in pure culture. The alga exhibits no specific organic growth-substance requirements. Growth is markedly stimulated by a source of organic nitrogen.
AN ANALYTICAL STUDY OF CHROMOSOME BEHAVIOR IN A WHEAT HAPLOID
Authors: Person Clayton
Published: August 2008

Bivalents, univalents, end-to-end and side-by-side associations, also chromosome distributions to the poles were associatively recorded for each of approximately 2000 meta-anaphase cells of a haploid Triticum aestivum L. It was demonstrated that the distribution of the univalents to the polar groups was not random. An inverse relationship between side-by-side association and bivalent frequencies was also demonstrated, and this formed the first in a series of analytical steps which led to a description of chromosome movement in the haploid. The validity of certain assumptions concerning chromosome behavior was tested using the χ2 method; for others, confirmatory observations were made in monosomic cells.
MORPHOLOGICAL DEVELOPMENT OF NODULES ON CARAGANA ARBORESCENS LAM.
Authors: Allen Ethel K. , Gregory K. F. , Allen O. N.
Published: August 2008

Developmental stages of nodules on Caragana arborescens, a woody perennial leguminous species, were studied. Root hair invasion and early cortical infection conformed to the well-known description of herbaceous leguminous nodules having apical meristems, except that a relatively smaller number of cells was infected. In the region of maturation behind the nodule meristem the infection threads remained active throughout the growth of the nodule and served to spread the infection to newly-formed cells. In mature nodules the distribution of red pigment, leghemoglobin, corresponded exactly with the location of the active bacteroidal tissue in the apical zones. Endodermal thickening of the vascular sheath and suberization of the nodule endodermis apparently restricted nutrient diffusion and aeration within the proximal areas. Senescence commenced relatively early, presumably as a result of these factors. However, the thickening of cell walls in these areas delayed, or prevented, necrosis; and a protective periderm which supplanted the outer cortex enhanced longevity of the nodule. Nodule rootlets projecting from six- to eight-month-old nodules were observed. The development of these rootlets from lateral branches of vascular strands and from terminal extensions of the apical tips of vascular bundles within the nodule is described.
SPECIFICITY IN THE EFFECT OF HIGH TEMPERATURE ON THE ADULT PLANT REACTION OF WHEAT VARIETIES TO RACES OF STEM RUST
Authors: Green G. J. , Johnson T.
Published: August 2008

The reactions of adult plants of 10 wheat varieties to stem rust (Puccinia graminis f. sp. tritici Erikss. & Henn.) races 11, 12, 15A, 15B-1, 15B-2, 15B-3, 17A, 29, 29A, and 139 were determined at temperatures of about 60° F. and 80° F. The varieties K338 AC 2.E.2 and K117A were resistant to all races at both temperatures. Redman was resistant to all races at both temperatures except for the races 15B-1, -2, -3, which attacked it at both temperatures. This variety was somewhat more susceptible to race 12 at the low than at the high temperature. The other varieties were more susceptible at the high temperature to one or more races to which they were resistant at the low temperature. McMurachy was more susceptible at the high than at the low temperature to races 15B-1, 15B-2, and 17A; Selkirk to races 15B-1 and 15B-2; Red Egyptian to races 15B-1 and 17A; Triticum timopheevi to races 15B-1, 15B-2, and 15B-3; Frontana × Thatcher II-47-37 to race 15B-1; Kentana to races 12 and 15B-2; and K58 to races 12, 15A, 17A, and 29. Since the resistance of these varieties broke down to different races, the effect of high temperature on the rust reaction of adult plants is specific for certain combinations of host variety and rust race.