bluuebunny/crossref_metadata_2025 huggingface dataset:
A Variable Fidelity Model Management Framework for Designing Multiphase Materials
Authors: Mejía-Rodríguez Gilberto , Renaud John E. , Tomar Vikas
Published: August 2008

Research applications involving design tool development for multi phase material design are at an early stage of development. The computational requirements of advanced numerical tools for simulating material behavior such as the finite element method (FEM) and the molecular dynamics (MD) method can prohibit direct integration of these tools in a design optimization procedure where multiple iterations are required. One, therefore, requires a design approach that can incorporate multiple simulations (multiphysics) of varying fidelity such as FEM and MD in an iterative model management framework that can significantly reduce design cycle times. In this research a material design tool based on a variable fidelity model management framework is presented. In the variable fidelity material design tool, complex “high-fidelity” FEM analyses are performed only to guide the analytic “low-fidelity” model toward the optimal material design. The tool is applied to obtain the optimal distribution of a second phase, consisting of silicon carbide (SiC) fibers, in a silicon-nitride (Si3N4) matrix to obtain continuous fiber SiC–Si3N4 ceramic composites with optimal fracture toughness. Using the variable fidelity material design tool in application to two test problems, a reduction in design cycle times of between 40% and 80% is achieved as compared to using a conventional design optimization approach that exclusively calls the high-fidelity FEM. The optimal design obtained using the variable fidelity approach is the same as that obtained using the conventional procedure. The variable fidelity material design tool is extensible to multiscale multiphase material design by using MD based material performance analyses as the high-fidelity analyses in order to guide low-fidelity continuum level numerical tools such as the FEM or finite-difference method with significant savings in the computational time.
Self-Collision Detection in Spatial Closed Chains
Authors: Ketchel John S. , Larochelle Pierre M.
Published: August 2008

A novel methodology for detecting self-collisions in spatial closed kinematic chains is presented. In general these chains generate complex three dimensional motions in which their own links will collide with each other (i.e., a self-collision) without effective motion planning. The self-collision detection is accomplished via a novel algorithm for definitively detecting collisions of right circular, cylindrically shaped, rigid bodies moving in three dimensions. The algorithm uses line geometry and dual number algebra to exploit the geometry of right circular cylindrical objects to facilitate the detection of collisions. In the first stage of the algorithm, cylindrically shaped rigid bodies are modeled by infinite length right circular cylinders. Sufficient and necessary conditions are then used to determine if a pair of infinite length cylinders collide. If the actual finite length rigid bodies collide, then it is necessary that their associate infinite length cylinder models collide, and we proceed to the next stage of the algorithm where the bodies are modeled with finite length cylinders and a definitive necessary and sufficient collision detection algorithm is employed. The result is an efficient approach of detecting collisions of cylindrically shaped bodies moving in three dimensions that has applications in spatial mechanism design and motion planning. A case study examining a spatial 4C mechanism for self-collisions is included.
A Concept for a Material That Softens With Frequency
Authors: Prasad J. , Diaz A. R.
Published: August 2008

This work presents design concepts to synthesize composite materials with special dynamic properties, namely, materials that soften at high frequencies. Such dynamic properties are achieved through the use of a two-phase material that has inclusions of a viscoelastic material of negative elastic modulus in a typical matrix phase that has a positive elastic modulus. A possible realization of the negative-stiffness inclusion phase is presented. A numerical homogenization technique is used to compute the average viscoelastic properties of the composite. The method and the properties of a composite material designed with it are demonstrated through an example.
Effects of Exposure of
Clostridium difficile
PCR Ribotypes 027 and 001 to Fluoroquinolones in a Human Gut Model
Authors: Saxton Katie , Baines Simon D. , Freeman Jane , O'Connor Rachael , Wilcox Mark H.
Published: August 2008

The incidence of
Clostridium difficile
infection is increasing, with reports implicating fluoroquinolone use. A three-stage chemostat gut model was used to study the effects of three fluoroquinolones (ciprofloxacin, levofloxacin, and moxifloxacin) on the gut microbiota and two epidemic
C. difficile
strains, strains of PCR ribotypes 027 and 001, in separate experiments.
C. difficile
total viable counts, spore counts, and cytotoxin titers were determined. The emergence of
C. difficile
isolates with reduced antibiotic susceptibility was monitored with fluoroquinolone-containing medium, and molecular analysis of the quinolone resistance-determining region was performed.
C. difficile
spores were quiescent in the absence of fluoroquinolones. Instillation of each fluoroquinolone led to
C. difficile
spore germination and high-level cytotoxin production. High-level toxin production occurred after detectable spore germination in all experiments except those with
C. difficile
PCR ribotype 027 and moxifloxacin, in which marked cytotoxin production preceded detectable germination, which coincided with isolate recovery on fluoroquinolone-containing medium. Three
C. difficile
PCR ribotype 027 isolates and one
C. difficile
PCR ribotype 001 isolate from fluoroquinolone-containing medium exhibited elevated MICs (80 to ≥180 mg/liter) and possessed mutations in
gyrA
or
gyrB
. These in vitro results suggest that all fluoroquinolones have the propensity to induce
C. difficile
infection, regardless of their antianaerobe activities. Resistant mutants were seen only following moxifloxacin exposure.
The Cyclic AMP Receptor Protein, CRP, Is Required for Both Virulence and Expression of the Minimal CRP Regulon in
Yersinia pestis
Biovar microtus
Authors: Zhan Lingjun , Han Yanping , Yang Lei , Geng Jing , Li Yingli , Gao He , Guo Zhaobiao , Fan Wei , Li Gang , Zhang Lianfeng , Qin Chuan , Zhou Dongsheng , Yang Ruifu
Published: August 2008

The cyclic AMP receptor protein (CRP) is a bacterial regulator that controls more than 100 promoters, including those involved in catabolite repression. In the present study, a null deletion of the
crp
gene was constructed for
Yersinia pestis
bv. microtus strain 201. Microarray expression analysis disclosed that at least 6% of
Y. pestis
genes were affected by this mutation. Further reverse transcription-PCR and electrophoretic mobility shift assay analyses disclosed a set of 37 genes or putative operons to be the direct targets of CRP, and thus they constitute the minimal CRP regulon in
Y. pestis
. Subsequent primer extension and DNase I footprinting assays mapped transcriptional start sites, core promoter elements, and CRP binding sites within the DNA regions upstream of
pla
and
pst
, revealing positive and direct control of these two laterally acquired plasmid genes by CRP. The
crp
disruption affected both in vitro and in vivo growth of the mutant and led to a >15,000-fold loss of virulence after subcutaneous infection but a <40-fold increase in the 50% lethal dose by intravenous inoculation. Therefore, CRP is required for the virulence of
Y. pestis
and, particularly, is more important for infection by subcutaneous inoculation. It can further be concluded that the reduced in vivo growth phenotype of the
crp
mutant should contribute, at least partially, to its attenuation of virulence by both routes of infection. Consistent with a previous study of
Y. pestis
bv. medievalis,
lacZ
reporter fusion analysis indicated that the
crp
deletion resulted in the almost absolute loss of
pla
promoter activity. The plasminogen activator encoded by
pla
was previously shown to specifically promote
Y. pestis
dissemination from peripheral infection routes (subcutaneous infection [flea bite] or inhalation). The above evidence supports the notion that in addition to the reduced in vivo growth phenotype, the defect of
pla
expression in the
crp
mutant will greatly contribute to the huge loss of virulence of this mutant strain in subcutaneous infection.
Prostaglandin E2Produced byEntamoeba histolyticaBinds to EP4 Receptors and Stimulates Interleukin-8 Production in Human Colonic Cells
Authors: Dey Indranil , Chadee Kris
Published: August 2008

Entamoeba histolyticapathogenesis in the colon occurs in a stepwise fashion. It begins with colonization of the mucin layer, which is followed by stimulation of a proinflammatory response that causes nonspecific tissue damage that may facilitate parasite invasion of the underlying colonic mucosa. Unfortunately, the parasite and/or host factors that stimulate a proinflammatory response in the gut are poorly understood. In this study, we found that liveE. histolyticaor secretory or proteins (SP) and soluble ameba components (SAP) can markedly increase interleukin-8 (IL-8) mRNA expression and protein production in colonic epithelial cells. The IL-8-stimulating molecule produced by live amebae was identified as prostaglandin E2(PGE2) as trophozoites treated with cyclooxygenase inhibitors inhibited the biosynthesis of PGE2and eliminated IL-8 production induced by live parasites or ameba components. Moreover, using specific prostaglandin EP2 and EP4 receptor agonists and antagonists, we found that PGE2binds exclusively through EP4 receptors in colonic epithelial cells to stimulate IL-8 production. Silencing of EP4 receptors with EP4 small interfering RNA completely eliminated SP- and SAP-induced IL-8 production. These studies identified bioactive PGE2as a one of the major virulence factors produced byE. histolyticathat can stimulate the potent neutrophil chemokine and activator IL-8, which can trigger an acute host inflammatory response. Thus, the induction of IL-8 production in response toE. histolytica-derived PGE2may be a mechanism that explains the initiation and amplification of acute inflammation associated with intestinal amebiasis.
Strength development with burial in fine-grained sediments from the Saguenay Fjord, Quebec
Authors: Perret D. , Locat J. , Leroueil S.
Published: August 2008

Following a sedimentological and geotechnical investigation, two main types of materials were identified in the Saguenay Fjord: (1) organic-rich sediments deposited by continuous sedimentation, and (2) unbioturbated sediments deposited rapidly by episodic events. The consolidation state of sediments with depth were analysed. In all subsurface deposits, sediments are overconsolidated irrespective of the depositional processes. However, in continuously deposited sediments, strength develops more rapidly than in turbidites or mass flows. In the surficial bioturbated layer, strength and liquidity index gradients are at a maximum and the rate of strength variation can reach values as high as 9 kPa/kPa. Results from one-dimensional creep tests suggest that in the organic-poor turbidites, the strength development is controlled, at least partly, by thixotropic strengthening. For bioturbated clays, it appears that the viscosity and the aggregating potential of organic matter controls the evolution of the strength with burial. Key words : Saguenay Fjord, marine clays, consolidation, turbidite, organic matter, bioturbation.
Experiments on granular flows to predict avalanche runup
Authors: Chu T. , Hill G. , McClung D.M. , Ngun R. , Sherkat R.
Published: August 2008

Design of deflectors or barriers to slow or stop snow avalanche debris in the runout zone requires estimates of runup height. In this paper, experimental data on runup of dense, dry granular flows in a flume are presented. The data are then compared with two one-dimensional theoretical equations for runup estimation: (1) a formulation based on following the leading edge of the flow up the barrier and (2) the traditional method adapted from equations presented by A. Voellmy for describing the centre of mass of the avalanche. The results show that the leading-edge model more closely matches the experimental results and, in field applications, the leading-edge model is expected to provide higher and, therefore, more conservative runup estimates. Key words : avalanche run-up, granular flows, avalanche defences, runout zone.
The mechanics of a pop-up: a stress relief phenomenon
Authors: Roorda John
Published: August 2008

The mechanical behaviour of a "pop-up" in a layered, near-surface rock formation under compression is examined by treating it as a one-way buckling problem in which a compressed flat plate lying on a horizontal substrate can suddenly buckle upward. Axi-symmetric deformation is assumed, the plate has self-weight, and frictional forces resist relative motion between the supporting substrate and the plate. It is found that, given a small initial disturbance, the plate may bulge upward in an explosive manner provided the in situ compressive in-plane stress exceeds a critical value. This phenomenon, which frequently happens in quarrying operations, acts as a stress relief mechanism that affects not only the localized buckle but also a large radial area surrounding the pop-up as inward slippage occurs. A numerical example of the upheaval of a limestone plate is presented. Key words : pop-up, buckle, rock strata, stress relief.
Frost protection of buried PVC water mains in western Canada: Reply
Authors: Sepehr K. , Goodrich L.E.
Published: August 2008

not available
POPULATION CYCLES AND COLOR PHASE GENETICS OF THE COLORED FOX IN QUEBEC
Authors: Butler L.
Published: August 2008

The pelt collection figures for colored fox in the province of Quebec were examined. The figures for the central and southern part of the province show a typical nine-year cycle. In the northern sections the data show that until 1930 there was a nine-year cycle in colored fox coexisting with a four-year cycle in white fox. After 1930 the four-year and nine-year cycles exist simultaneously with the four-year gradually dominating the scene. In the Upper James Bay region the typical nine-year cycle shows a supplementary peak corresponding with the four-year peak observed in the regions to the north. The coat color phase ratios cannot be explained by monohybrid equilibrium but they are consistent with the view that the population consists of isolates. A partial breakdown of isolate barriers would account for the ratios observed without the necessity of the large unexplained gene frequency changes which occur if panmixia is postulated. Migration causes the breakdown of isolate barriers and this accounts for the sudden shift in gene frequency and explains the long term trends which have resulted in a lower percentage of the silver phase. The degree of isolation changes with the population pressures. The cause of the cycles appears to be resident in the respective area in which the animal breeds. Both the cycle and the color phase data indicate that northward migrations have taken place.
NUTRITION DES LARVES DE TRIBOLIUM CONFUSUM DUVAL: I. RECHERCHE D'UN RÉGIME SYNTHÉTIQUE BASAL SATISFAISANT LEURS BESOINS NUTRITIFS
Authors: Lemonde A. , Bernard R.
Published: August 2008

A purified diet suitable for the study of the qualitative amino acids requirements of the larvae of the Coleoptera Tribolium confusum is presented. The composition of the diet is as follows: amino acid mixture 20%, cornstarch 75.5%, cholesterol 1%, wheat germ oil 1.5%, salt mixture No. 2 U.S.P. XII 2%, yeast 0.5%, vitamin mixture M.V.–II. In presence of amino acids, glucose cannot be used as a source of hydrocarbon. The mixture is very hygroscopic, develops a brown color, and is apparently toxic to the larvae. The importance of choline as a growth factor is demonstrated. Wilson's Liver Fraction L or Liver Concentrate 1: 20 cannot replace this vitamin. Yeast appears to contain unknown factors for it improves growth when added to a diet already supplemented with vitamins known to be essential for the larvae. A mixture of 19 crystalline amino acids known to occur in casein satisfies the nitrogen requirements of the larvae of T. confusum equally as well as purified casein.
NUTRITION DES LARVES DE TRIBOLIUM CONFUSUM DUVAL: II. IMPORTANCE DES ACIDES AMINES
Authors: Lemonde A. , Bernard R.
Published: August 2008

The normal pupation period of Tribolium confusum on whole wheat diet averages 18 days. In presence of a purified diet containing 19 crystalline amino acids known to exist in casein, the pupation period is increased to 28 days. Removal of one of the amino acids considered as nonessential for growth in the rat from such a diet, results in pupation periods falling between 26 and 32 days. On the other hand, omission of lysine, threonine, phenylalanine, methionine, isoleucine, and arginine, one at a time, increases the pupation period from 61 to 70 days. If valine, tryptophane, histidine, or leucine are left out singly, pupation is prevented, though two-thirds of the larvae survive. It is concluded that the amino acids known to be essential for growth in the rat are also essential for growth and pupation of the larvae of T. confusum. Four of these essential amino acids appear to be connected with the phenomenon of pupation.
DESCRIPTION OF METABRONEMA PREVOSTI SP. NOV. WITH A NOTE ON THE GENUS AND A LIST OF ITS SPECIES AND THEIR HOST AND GEOGRAPHICAL DISTRIBUTION
Authors: Choquette L. P. E.
Published: August 2008

Metabronema prevosti sp. nov. is described from Ameirus nebulosus nebulosus (Le Sueur) and the systematic status of the genus Metabronema Yorke and Maplestone, 1926, in relation to other spirurid genera is reviewed briefly. A list of the species of the genus, their hosts, and geographical distribution is given.
OBSERVATIONS ON THE DEVELOPMENT OF STRONGYLOIDES AGOUTII OF THE AGOUTI IN THE GUINEA PIG
Authors: Reesal Michael R.
Published: August 2008

The development from infective larva to adult female of S. agoutii in the guinea pig is described. In this animal the adult worm lives only for six weeks, the host becoming immune after this period. Egg production is much more rapid than in the agouti in which animal the parasite has a life of over a year.
PARACUARIA MACDONALDI n.g., n.sp. (FAMILY ACUARIIDAE, SUBFAMILY ACUARIINAE) FROM THE SEA GULL (LARUS ARGENTATUS)
Authors: Rao N. S. Krishna
Published: August 2008

Paracuaria macdonaldi n.g., n.sp. (family Acuariidae, subfamily Acuariinae) is described from the sea gull, Larus argentatus.
ECHINOCHASMUS COHENSI N.SP. (FAMILY ECHINOSTOMIDAE, SUBFAMILY ECHINOCHASMINAE) FROM THE SEA GULL, LARUS ARGENTATUS
Authors: Rao N. S. Krishna
Published: August 2008

Echinochasmus cohensi n.sp. (family Echinostomidae, subfamily Echinochasminae) is described from the sea gull, Larus argentatus Brünn.
OBSERVATIONS ON THE BIONOMICS OF SOME NORTHERN SPECIES OF TABANIDAE (DIPTERA)
Authors: Miller L. A.
Published: August 2008

Ten species of Tabanus, five of Chrysops, and one of Atylotus are recorded from the Churchill, Manitoba, area. Of these, Tabanus itasca Philip, Tabanus sp. (new?), and Atylotus ohioensis (Hine) represent new records. It is established that Tabanidae in this region overwinter in the larval stage and that most species have at least a three-year life cycle. Problems in taxonomy are discussed. Methods of rearing the immature stages, of collecting adults emerging in the field, of estimating larval and adult populations, and of correlating adult activity and weather conditions are described, and the results are presented. Larvae of the tipulid Prionocera dimidiata (Lw.) are reported as predators of larvae of Chrysops spp. The emergence of the chalcid parasite Diglochis occidentalis (Ashm.) from pupae of Tabanus and Chrysops spp. reared from the larval stage is recorded.
THE EFFECT OF GONADAL HORMONES ON THE NUCLEIC ACID CONTENT OF LIVER AND SERUM IN THE IMMATURE PULLET, AND THE DIFFERENCE BETWEEN THE NUCLEIC ACID CONTENT OF THE LIVERS OF SEXUALLY MATURE PULLETS AND COCKERELS
Authors: Common R. H. , Chapman D. G. , Maw W. A.
Published: August 2008

Treatment of sexually immature pullets with testosterone propionate so as to evoke changes in combs and wattles similar to normal puberal changes did not affect liver weight or liver content of nucleic acids. Estradiol benzoate, or estradiol benzoate plus testosterone propionate, increased liver weight and total liver pentose nucleic acid, and slightly increased liver desoxypentose nucleic acid. Chemical evidence is adduced in support of the view that the increase of liver crude protein caused by estrogen is a consequence of cellular hypertrophy accompanied by a slight degree of hyperplasia. The ratio RNAP: DNAP was relatively high in the liver of the young chicken, but declined somewhat during the first 12 weeks. With the onset of reproductive activity, the ratio RNAP: DNAP increased in the livers of the females but did not show a similar tendency in the males. The results suggest that there is a sexual differentiation in the nucleic acid content of the livers of the mature fowl, and that this is reasonably attributable to endogenous estrogen activity. Data are presented in confirmation of the reported effect of estrogen in increasing serum or plasma nucleic acid in the fowl, androgen being without any such effect.
PARASITES OF FRESHWATER FISH: V. PARASITIC HELMINTHS OF THE MUSKALLUNGE, ESOX M. MASQUINONGY MITCHILL, IN THE ST. LAWRENCE WATERSHED
Authors: Choquette L. P. E.
Published: August 2008

The incidence of the following species of helminths recovered from the digestive tract of 218 muskallunge, Esox m. masquinongy, from various localities in the St. Lawrence watershed is recorded: Azygia augusticauda, A. longa, Triaenophorus nodulosus, Proteocephalus pinguis, Neoechinorhynchus cylindratus, Leptorhynchoides thecatus, Metabronema salvelini, and Rhaphidascaris canadensis. One hundred and ninety-two, or 88% of the fish examined were found to harbor one or more species. The most commonly found species were T. nodulosus and A. longa. In all cases the number of worms recovered per host was small.
THE EFFECTS ON THE GRASSHOPPER, MELANOPLUS MEXICANUS MEXICANUS (SAUSS.) (ORTHOPTERA: ACRIDIDAE), OF VARYING THE NITROGEN CONTENT IN ITS FOOD PLANT
Authors: Smith D. S. , Northcott F. E.
Published: August 2008

Melanoplus mexicanus mexicanus (Sauss.), from time of hatching, was fed on wheat (Renown) grown in nutrient solutions of varying nitrogen content. Some wheat was produced with an average nitrogen content of 6.16% (dry weight), some with 4.29%, and some with 3.33%. Survival and development were greatest on the high nitrogen wheat, least on the low. On the low nitrogen wheat no individuals developed beyond the last nymphal instar. Neither weight of adults nor the sex ratio was affected by the various foods. Females fed on wheat with a high nitrogen content laid more eggs but the viability of the eggs was not affected.
LIFE HISTORY OF LEUCOCYTOZOON SIMONDI MATHIS AND LEGER IN NATURAL AND EXPERIMENTAL INFECTIONS AND BLOOD CHANGES PRODUCED IN THE AVIAN HOST
Authors: Fallis A. Murray , Davies Douglas M. , Vickers Marjorie A.
Published: August 2008

Ducks exposed outdoors in Algonquin Park during the summer became infected with Leucocytozoon simondi and many of them died from the infection in June and July when black flies were abundant. The minimum prepatent period was five and a half days. Young parasites were observed in erythrocytes and lymphocytes; mature gametocytes, as shown by exflagellation of microgametocytes, occurred in round and elongated host cells. Asexual development was observed in the spleen, liver, heart, brain, lung, lymphoid tissue, and pancreas. The schizonts were large and contained, at maturity, more than a million merozoites about 1 μ in diameter. Sexual development of the parasites within two species of black flies was completed in three days at summer temperature. Ookinetes were present in the stomach of black flies about four to six hours after the flies had ingested blood containing gametocytes. Developing oocysts were found free among the stomach contents of flies 40–48 hr. after the blood meal. Sporozoites were observed between 60–70 hr. after the flies had ingested gametocytes. Artificial infections were produced in ducks following the injection of macerated black flies that had fed two and one-half to seven days previously on infected ducks. The resulting infections were less severe than those that resulted from natural infections, although the pattern was similar and a minimum prepatent period of eight days was observed. The asexual cycle was completed in fewer than six days although some asynchronicity was apparent. Artificial infections were produced following the injections of blood, spleen, liver, lung, and bone marrow that were taken from ducks at various intervals following their exposure to natural infection. The minimum prepatent period in these infections was eight days and low parasitemias were produced. Gametocytes survived for at least one week in peripheral blood. Ducks developed some resistance following repeated infections but single infections did not protect ducks that were exposed to infection six weeks later. Heavy infections developed in ducks that were splenectomized. The leucocytosis and anemia associated with infections were measured and recorded.
POLARIZED LIGHT AND BODY TEMPERATURE LEVEL AS ORIENTATION FACTORS IN THE LIGHT REACTIONS OF SOME HYMENOPTEROUS AND LEPIDOPTEROUS LARVAE
Authors: Wellington W. G. , Sullivan C. R. , Green G. W.
Published: August 2008

Larvae of the diprionid sawfly, Neodiprion banksianae Roh., the lasiocampid, Malacosoma disstria Hbn., and the tortricid, Choristoneura fumiferana (Clem.), were used to demonstrate the effects of heat and of plane-polarized light upon the photic orientation of immature insects. Photic orientation was shown to be primarily a result of internal temperature level. When larvae were heated sufficiently, they reversed the sign of their orientation. Larvae of the three species were sensitive to variations in the plane of polarization, and they used the polarization pattern of the sky to varying degrees in their orientation. Neodiprion larvae orientated primarily with reference to the polarization pattern when one was available. Malacosoma larvae and photonegative Choristoneura larvae appeared to orientate with reference to the position of the sun, but rotation of the axis of a "Polaroid" screen through 90° could change the direction of their travel by this amount. On the other hand, photonegative Choristoneura larvae subjected to a 90° shift of the axis continued to orientate with reference to the solar compass position when the sun was visible, even when their actions under the "Polaroid" showed that they could detect changes in polarization. The type of eye structure, the number of pairs of eyes, and the position of these on hypognathous and prognathous heads are considered to have some influence upon the different degrees of efficiency in orientation. Smoke and ice crystal cloud affected the orientation of the "Polaroid" axis that would produce a response, notably when the sun was obscured. Water droplet cloud had little effect, except in a complete overcast, under which polarization was disrupted.
STUDIES ON THE ENDOPARASITIC FAUNA OF TRINIDAD MAMMALS: VIII. PARASITES OF MARSUPIALS
Authors: Wolfgang R. W.
Published: August 2008

Two species of Trematoda and 17 of Nematoda were recovered from three species of opossums. Of these, a trematode (Zonorchis philanderi), and seven nematodes (Cruzia cameroni, Subulura trinitatis, Camerostrongylus didelphis, Philostrongylus philanderi, Spirocerca cylicola, Trichuris urichi, and T. reesali) are new.
DISEASE IN CODLING MOTH LARVAE PRODUCED BY SEVERAL STRAINS OF BACILLUS CEREUS
Authors: Stephens June M.
Published: August 2008

This paper describes a bacteriological study of strains of Bacillus cereus Frankland and Frankland producing disease in codling moth larvae and an investigation of their pathogenicity. Strains of the bacterium were pathogenic to the codling moth by feeding or by injection.
DIETARY FAT AND TEMPERATURE TOLERANCE OF GOLDFISH
Authors: Hoar William S. , Cottle Merva K.
Published: August 2008

Resistance of goldfish to low as well as to high temperatures may be changed by feeding diets containing different fats in high concentration. There is no evident relationship between melting point of the natural fats (pilchard oil, herring oil, and lard) and tolerance to cold. Hydrogenation of pilchard oil used in the diets reduces resistance of goldfish to both low and high temperatures. Fish fed on hydrogenated cottonseed oil show a similar reaction to high temperatures. These findings are contrary to the theory that increased thermal resistance is associated with higher melting point fats. It is suggested that the presence of double bonds in the lipids is important in maintaining the integrity of the plasma membrane.
USE OF DAILY METABOLIC PERIODICITIES AS A MEASURE OF THE ENERGY EXPENDED BY VOLUNTARY ACTIVITY OF MICE
Authors: Hart J. S.
Published: August 2008

At temperatures of 10, 20, and 30 °C., average metabolism of 12 mice in small respiration chambers was significantly greater during the night than during the day but was sensibly the same at night and day when constant work levels were imposed in a treadmill apparatus. In these tests the increase in metabolism due to work varied only slightly, if at all, with temperature. It is concluded that diurnal variation in metabolism in the small chambers resulted mainly from variation in voluntary muscular activity. On this supposition, it is estimated that the energy expended in voluntary activity averaged 2350 cal. per mouse per 24 hr. at all these temperatures, which was 12, 16, and 27% of the total daily expenditure at 10, 20, and 30 °C. respectively.
THE EFFECTS OF RADIATION ON THE HABITAT TEMPERATURES OF THE LODGEPOLE NEEDLE MINER, RECURVARIA MILLERI BUSCK (GELECHIIDAE: LEPIDOPTERA)
Authors: Henson W. R. , Shepherd R. F.
Published: August 2008

The lodgepole needle miner (Recurvaria, milleri Busck) passes the greater part of its life in the interior of needles of its host tree. Investigations of the temperature of needle mines and its relation to ambient air temperature, radiation, and a number of other weather factors are reported. Incoming solar radiation shows a heating effect on the needle mines which is directly proportional to the radiation level. The heating effect of the radiation is modified by other weather factors, by differences in the exposure of the needles, and by the type of mines in the needles. At night, needles are cooled below ambient air temperatures by outgoing radiation, which in turn is dependent on the nocturnal weather. The application of these results to studies of the effect of temperature on the needle miner can only be made with respect to individual needles. Thus, radiation of 1.5 gm-cal. per cm.2 per min. will elevate the temperature of a needle 6.3 Centigrade degrees in air moving at less than one mile per hour if the needle is orientated at right angles to the sun and fully exposed. Shade from other needles, wind over one mile per hour, and needle orientation other than 90° to the sun's rays all tend to reduce the amount of heating at the indicated level of radiation.
EFFECTS OF STARVATION ON LARVAE OF THE PALE WESTERN CUTWORM, AGROTIS ORTHOGONIA MORR. (LEPIDOPTERA: PHALAENIDAE)
Authors: Jacobson L. A.
Published: August 2008

All larval instars of the pale western cutworm, Agrotis orthogonia Morr., were starved for varying periods at 10°, 15°, 20°, and 25 °C. Mortality curves indicated varying individual susceptibility or resistance to starvation. The time required for 100% mortality varied inversely with temperature and directly with size of larvae. The rate of mortality of newly hatched larvae whether fed or unfed was nearly the same at all temperatures. Application of the findings to recommended control practices is discussed.
STUDIES ON THE BIOLOGY OF THE MUSKRAT IN MANITOBA: PART I. OESTROUS CYCLE AND BREEDING SEASON
Authors: McLeod J. A. , Bondar G. F.
Published: August 2008

A study of oestrus in female muskrats was conducted during the summers of 1950 and 1951 as part of a five year investigation of the biology of the muskrat in Manitoba. Two captive females examined daily by the vaginal smear method from June 30 to Aug. 10, 1950, inconclusively indicated an oestrous cycle length of about 30 days which agreed with the findings of Beer on Wisconsin muskrats. In 9151 10 female muskrats of various ages and of different lengths of time in captivity were examined daily beginning on March 13 and continuing until August 15. The data obtained at this time showed a considerable variation in the lengths of the oestrous cycles in different females or, even, in the same individual from time to time. The minimum time required for the completion of an oestrous cycle was found to be two days while the maximum time observed was 22 days. On the basis of 136 complete oestrous cycles studied, the modal time was found to be approximately four days and the mean time 6.1 days. The longer cycles found by ourselves in 1950 and by Beer are interpreted as representing pseudopregnancies and not oestrous cycles. Failure of muskrats to mate in captivity or in the wild during the latter part of the summer is attributed to sexual inactivity of the males and not the females.
THE IMPORTANCE OF THE LOCUS OF APPLICATION ON THE EFFECTIVENESS OF DDT FOR THE HOUSE FLY, MUSCA DOMESTICA L. (DIPTERA: MUSCIDAE)
Authors: Fisher R. W.
Published: August 2008

DDT-benzene droplets, 1.5 ml. and up, produced by a 0.25 ml. syringe combined with a microfine glass tube and a rocking microtome (to regulate the plunger movement) were collected, evaporated on water, and applied as saturated droplets or crystalline masses to 16 different areas of the integument of adult Musca domestica L. males harmlessly immobilized in cellulose tape holders.Crystalline DDT on the pulvilli of one leg or injected into muscle was ineffective. DDT in benzene was more effective than crystalline DDT. Effectiveness increased as loci of application approached the body or head; was enhanced by pulsatile membranes beneath loci; was greatest and most rapid when the labella were treated; was increased as the area of intact integument surrounding the locus was increased; but was not enhanced by additional cuticular waxes in the benzene solvent.
EFFECTS OF SOME HORMONES ON THE BEHAVIOR OF SALMON FRY
Authors: Hoar William S. , MacKinnon Dixon , Redlich Aline
Published: August 2008

Chum and coho salmon fry, when immersed in solutions of methyl testosterone, synthetic thyroxine sodium, or the antithyroid drug, thiourea, do not show any new or different patterns of behavior. Chum salmon fry do, however, show quantitative changes in the rate of swimming and in the intensity of schooling. Less marked variations are seen in aggregating behavior of the treated coho. Control chum fry swim in the brightest part of a horizontal light gradient while coho fry, coho smolt, and trout prefer darker areas. Minor changes in this photoresponse, observed in fish treated with drugs, are probably produced by variations in the amount of swimming.
DIROFILARIA DESPORTESI SP. NOV., A FILARIID FROM THE BLACK BEAR IN CANADA
Authors: Choquette Laurent P. E.
Published: August 2008

Dirofilaria desportesi sp. nov. (Family Filariidae, subfamily Filariinae) is described from the black bear (Euarclos americanus americanus).
THE HAEMOCYTES OF THE MEDITERRANEAN FLOUR MOTH, EPHESTIA KÜHNIELLA ZELL. (LEPIDOPTERA: PYRALIDIDAE)
Authors: Arnold J. W.
Published: August 2008

The haemocytes of the Mediterranean flour moth were arranged in four classes, prohaemocytes, plasmatocytes, spheroidocytes, and oenocytoids, by a modification of Yeager's classification system for the haemocytes of the southern army worm. Total and differential haemocyte counts were made in each stage of the insects' development. Total cell numbers increased gradually during larval life and reached their maximum in the prepupal period. They decreased markedly during pupation and remained at a low level during adult life. Plasmatocytes and spheroidocytes accounted for more than 90% of the total cells in most stages. The plasmatocytes were in the majority during most of the larval life but were superseded by the spheroidocytes in the prepupal period. The spheroidocytes also increased in numbers when larvae were subjected to certain abnormal conditions. Histochemical tests showed that the spheroidocytes were sites for the accumulation of neutral fats just before pupation.
OBSERVATIONS ON THE DEVELOPMENT OF LYMNAEA PALUSTRIS MÜLLER
Authors: McCraw Bruce M.
Published: August 2008

Observations were made in the laboratory on the egg-laying habits, egg masses, and embryos of isolated Lymnaea palustris Müller placed in equal volumes of water (415 cc.). It was found that the mean number of eggs per mass decreased as L. palustris oviposited more frequently, but that the mean percentage of embryos surviving to emerge from the masses increased. This inverse relation between egg production and survival of embryos resulted in the hatching of a mean number of embryos which was approximately constant for each of a series of ovipositions. The factors which may determine or influence this relation were discussed (amount of dissolved oxygen, temperature, volume and pH of the water, nutrition, and disease). Factors similar to those affecting the number of surviving embryos probably influenced the rate of decrement of egg production. Most of the egg masses were laid on a horizontal plane, suggesting that a balance mechanism operates, the snail showing preference for this position during egg deposition.
THE EARLY DEVELOPMENT OF A BOTTOM FAUNA IN A NEW POWER RESERVOIR IN THE ROCKY MOUNTAINS OF ALBERTA
Authors: Nursall J. R.
Published: August 2008

The Barrier reservoir, Alberta, was examined periodically from May, 1947, shortly after water impoundment began, until June 1949. The reservoir is fundamentally oligotrophic; rapid replacement of water, periodic fluctuation of the water level, and a marked annual deposition of sediment contribute to this condition. The bottom fauna, consisting chiefly of immature Chironomidae, was much influenced by these factors during the period of the investigation. A Pentapedilum–Chironomus–Tanytarsus succession is interpreted as indicating a change from original eutrophic conditions on the bottom to oligotrophic, as the rich leaf litter of the original bottom was lost under sediments.
MASS TAGGING OF BLACK FLIES (Diptera: Simuliidae) WITH RADIOPHOSPHORUS
Authors: Fredeen F. J. H. , Spinks J. W. T. , Anderson J. R. , Arnason A. P. , Rempel J. G.
Published: August 2008

A new method for tagging large numbers of black flies (Simulium spp.) for flight range investigations is described. Radioactive adults that were readily detected with a Geiger counter were reared from larvae that had been kept for 24 hr. in a very dilute solution of radioactive phosphorus (0.2 μc. per ml.) and then returned to nonradioactive water to complete their development. The treatment did not visibly harm larvae or the adults that emerged from them. Larvae were reared in small containers of water circulated and aerated with air jets in the laboratory, and with a simple arrangement of stream-driven paddle wheels in the field. By this method, tagged larvae, pupae, and adults were produced which could be readily detected with a Geiger counter. In field tests, tagged larvae and pupae were found as far as 520 yd. downstream from the point of release. Tagged adults were taken in cages placed over radioactive larvae and pupae in the stream, but only one was recaptured in the open, and this only 100 yd. from the stream. Failure to capture more tagged adults was believed due mainly to inadequate collecting methods. A short treatment period is desirable when tagging large populations of black-fly larvae in the field because other methods, such as rearing in a small container for a long period of time, or treating the stream with a radioactive isotope, are impractical. This method would be applicable in studies on dispersal and predation of immature and adult stages of other insects of streams and ponds.
THE CLYPEUS AND THE EPISTOMAL SUTURE IN HYMENOPTERA
Authors: DuPorte E. Melville , Bigelow R. S.
Published: August 2008

The frontoclypeal suture in the Hymenoptera does not arch upwards into the frontal region but retains its primitive position at the horizontal level of the mouth, the clypeus remaining preoral in position. The genae and postgenae have continued or resumed their ventral growth, the inner margins of the genae have fused with the previously free lateral edges of the clypeus, and a pair of clypeogenal sutures, continuous with the frontogenal, have formed along the lines of fusion. The clypeogenal sutures form the vertical or oblique elements of the U-shaped epistomal suture, while the frontoclypeal suture forms its horizontal component. The anterior tentorial pits, within the bases of the frontogenal sutures, lie at the junction of the frontoclypeal with the clypeogenal sutures. These changes in the structure of the face have caused a ventral shifting of the mandibular articulations.
RATE OF GAIN AND LOSS OF COLD RESISTANCE IN MICE
Authors: Hart J. Sanford
Published: August 2008

The resistance time of white mice acclimated to 10 and 30 °C, was 1730 min. and 67 min. respectively when both groups were exposed to −17 °C. After shifting the 30 °C. mice to 10 °C. and the 10 °C. mice to 30 °C., the resistance time of the original 30 °C. mice at −17 °C. became approximately the same in five weeks as that of the original 10 °C. mice and vice versa. Change of resistance time was greatest in the first two weeks and it gradually declined thereafter. Rate of loss of resistance in the first week was greater than rate of gain in terms of resistance time at −17 °C., but appeared slightly less than rate of gain in terms of resistance temperature. In white-footed mice, several short (two- to three-hour) exposures to cold increased cold resistance.
SOMATIC CHROMOSOMES OF HIGHER DIPTERA: I. DIFFERENTIATION OF TACHINID PARASITES
Authors: Boyes J. W. , Wilkes A.
Published: August 2008

A method of analysis of somatic chromosome complements in cells of the brains of larvae and pupae is presented. Tachinid species have regularly 12 chromosomes in their somatic complements. These consist of five metacentric pairs and a pair of sex chromosomes which are acrocentric in most species. Careful measurement, on drawings, of each arm of each chromosome provides a basis for calculating the percentage that each pair constitutes of the total complement length and for determining the ratio of the long to the short arm for each pair. Results of analysis and other distinguishing features of the chromosome complements are presented for Aplomya caesar, A. mitis, Ceracia dentata, Ceromasia auricaudata, Drino bohemica, Eumea westermanni, Lydella grisescens, Madremyia saundersii, Mericia ampelus, Nemorilla pyste, Neophorocera hamata, Omotoma fumiferanae, Phryxe pecosensis, Spathimeigenia sp., Winthemia datanae, and W. occidentis. Most of these species can be distinguished by differences in the morphology of their chromosomes.
THE DESOXYRIBONUCLEIC ACID CONTENT OF THE LIVER NUCLEI OF IMMATURE PULLETS TREATED WITH GONADAL HORMONES
Authors: Phillips W. E. J. , Maw W. A. , Common R. H.
Published: August 2008

Treatment of sexually immature pullets with estrogen, or with estrogen plus androgen, increased significantly the number of liver cell nuclei per kgm. live weight, but did not significantly affect the average amount of DNAP per nucleus (2.67 × 10−10 mgm. DNAP per nucleus). It is shown that increase in number of cells can account for approximately half the increase in liver weight evoked by estrogen or estrogen plus androgen. The rest of the increase may be in large part a consequence of cellular hypertrophy.
VARIATION IN ANAL FIN RAY COUNT OF THE REDSIDE SHINER RICHARDSONIUS BALTEATUS (RICHARDSON)
Authors: Lindsey C. C.
Published: August 2008

Anal fin rays were counted on 4766 specimens of Richardsonius balteatus from 61 localities in British Columbia. Individual counts varied from 10 to 21, and mean counts of different populations varied from 12.06 to 17.51. Significant differences in counts occurred between different bodies of water, between recently introduced populations and their parent stock, between different parts of the same lake, and between different year classes. Ray counts tended to be higher amongst females in populations with high over-all means, and higher amongst males in populations with low over-all means. A positive correlation was demonstrated between water temperatures recorded in the vicinity of developing fry and the mean numbers of anal rays produced. Within each latitudinal zone a similar correlation occurred between mean ray count and average air temperature during the spawning season, but data on 109 means of populations in U.S.A. and Canada indicated a tendency, probably genetic, towards production, at equivalent temperature, of higher ray count towards the northern end of the range. Loose correlations between anal ray count and certain other morphological characteristics suggest that these may be dependent on more or less common environmental factors but are not linked by direct causality.
THE EFFECT OF METAMORPHOSIS ON THE MULTIPLICATION OF AN INSECT VIRUS
Authors: Bird F. T.
Published: August 2008

The prepupal stage of the European spruce sawfly is immune to infection by a polyhedral virus disease. The virus multiplies only in the nuclei of the digestive cells of the mid-gut epithelium and during metamorphosis these are replaced by embryonic cells not susceptible to infection although they develop into digestive cells eventually. The prepupal mid-gut, a temporary gut, is composed entirely of embryonic cells. New digestive cells appear later in the pupal and adult stages and these rapidly become infected with virus.
THE NATURAL IMMUNITY OF THE LARCH SAWFLY (PRISTIPHORA ERICHSONII (HTG.)) TO THE INTRODUCED PARASITE MESOLEIUS TENTHREDINIS MORLEY, IN MANITOBA AND SASKATCHEWAN
Authors: Muldrew J. A.
Published: August 2008

By 1945 it was suspected that the larch sawfly in Saskatchewan and Manitoba had developed an immunity to the introduced parasite Mesoleius tenthredinis Morley. Results of subsequent studies showed that embryonic development of M. tenthredinis in sawfly larvae from Manitoba and Saskatchewan was inhibited three to four days after oviposition. No such inhibition occurred in larvae from British Columbia where the parasite is still highly effective. Inhibition seemed to be related to the deposition of phagocytic capsules around parasite embryos, which occurred in host larvae from Manitoba and Saskatchewan but not in larvae from British Columbia. Encapsulated parasite embryos were shown to be viable, for a number of them hatched after being placed in Ringer's solution. Viability decreased with age. Some embryos were viable seven months after oviposition, though the normal incubation period is 7 to 10 days. Unencapsulated embryos developed more rapidly than encapsulated embryos in Ringer's solution. Results obtained indicate that the phagocytes of the larch sawfly from Manitoba and Saskatchewan play an important role in the immunity reaction of this insect to M. tenthredinis.