bluuebunny/crossref_metadata_2025 huggingface dataset:
CFD, Thermal and Stress Analysis for daVinci X-Prize Manned Space Mission: Computational Design Analysis - Part 1 (Keynote Lecture)
Authors: Kudriavtsev Vladimir , Feeney Brian , Buneta Max , Krzeminski Marek , Ania Asier , Trauttmansdorff Michael , Todorcevic Stana , Balage Sudantha , Viechweg Michael
Published: August 2008

In the present article we review engineering and research efforts conducted by a group of volunteers with the help of advanced engineering commercial software (CFD-ACE+, ANSYS, CFD-FASTRAN, Matlab/Simulink, Autodesk Inventor, Maple) in support of the da Vinci Project, the first Canadian competitor in the International X Prize Competition. The da Vinci Project has an objective of launching the first private sub-orbital manned space flight by the end of 2004. Under X Prize rules the vehicle must be reusable, built to hold 3 people and complete 2 flights within a 2 week period. The basic launch configuration is to lift the rocket using a reusable helium balloon to a launch altitude of 24,400 meters (80,000 feet). The paper describes in detail the various major subsystem components of the Rocket, Balloon Launch Platform, Ground Operations and Logistics and the multidisciplinary approach to arrive at a viable and safe design. A state of the art software and engineering data management methodology is described. All parameters that effect the design are ported through a data management software linking, CFD, FEA and Flight Simulation software’s directly to the primary CAD platform resulting in direct updates to the CAD model. This process allows an iterative design to develop rapidly, multiple configurations to be assessed and a final design output in the shortest overall timeframe. The data management software contains every parameter in the rockets design including all rocket engine performance criteria. Running a variation on the engine lsp (Specific Impulse) results in the CAD drawings updated with new tank sizes etc, yet still driven by constrictions such as maximum diameter of the vehicle. Lowering of the Isp in such case would result in the need for more fuel to reach the minimum assigned altitude of 115 Km. The rockets length would automatically be increased, given a diameter restriction. CG and CP values for instance are automatically recalculated for stability analysis.
The Flows in Weightlessness Generated by Vibrations
Authors: Lyubimov D. , Lyubimova T. , Sharifulin A. , Volfson D.
Published: August 2008

Vibration phenomena play an important role in many technical processes involving heated interfaces in the microgravity environment. The analysis of vibration effect on non-isothermal fluid in closed cavity is important for planning technological experiments in space. Control and optimization of these processes critically depend on the understanding of liquid response to the vibrations. With this aim the theoretical investigation for two kinds of problems are performed for infinite plane and cylindrical fluid layers. First of all we investigated simple case of the fluid response-thermal vibrational convection in a cylindrical fluid layer with rigid conducting boundaries. It is found that steady modes of thermal vibrational convection are subjected to various bifurcations. Bifurcations cause shay changes in heat transfer. The generalized Lorenz model is modified and used to conduct the analysis of bifurcations caused by the changing of the cavity shape and vibrational Rayleigh number. The shape of steady-state surface in space of {ψ, Rv, γ} is found, where ψ is the streamfunction of mean flow, Rv is the vibrational Rayleigh number, γ is the cavity curvature. The solution correctly illustrates the general view of steady states surface for the parameter values corresponding to the cavity with the curvature close to zero (thin cylindrical layer). The numerical solution of the vibrational convection equations is performed for plane and cylindrical fluid layers. The results of the analysis based on the generalized Lorenz model are compared with the data obtained by direct numerical simulation. It is shown that the steady-state surface is different from that in the Lorenz model. The bifurcation curve with extremum is found. Thus, bifurcations of complex shape could be observed. This is impossible in a Lorenz model. Second set of investigated problems is related to thermo-vibrational flows caused by oscillations of the boundaries. A general class of oscillations of the boundaries is shown to produce specific mechanisms, of mean transport of vorticity in a uniform fluid, and in addition heat/concentration transport in non-uniform fluid. We performed analytical and numerical study of the flow between two infinite cylinders when the axis of the inner one is subjected to high frequency, small amplitude and oscillations of circular polarization. This type of oscillation produces basic Couette-like mean flow in the gap between the cylinders through the diffusion of vorticity generated in the boundary layers near the rigid surfaces (so-called Schlichting mechanism). The linear stability analysis for this flow with and without radial temperature gradient is performed. Non linear regimes are studied numerically by finite difference method. The results of numerical and analytical simulation of fluid motion for both types vibration interactions are discussed as well.
ABC Transporter Cdr1p Contributes More than Cdr2p Does to Fluconazole Efflux in Fluconazole-Resistant
Candida albicans
Clinical Isolates
Authors: Holmes Ann R. , Lin Ya-Hsun , Niimi Kyoko , Lamping Erwin , Keniya Mikhail , Niimi Masakazu , Tanabe Koichi , Monk Brian C. , Cannon Richard D.
Published: August 2008

Fluconazole (FLC) remains the antifungal drug of choice for non-life-threatening
Candida
infections, but drug-resistant strains have been isolated during long-term therapy with azoles. Drug efflux, mediated by plasma membrane transporters, is a major resistance mechanism, and clinically significant resistance in
Candida albicans
is accompanied by increased transcription of the genes
CDR1
and
CDR2
, encoding plasma membrane ABC-type transporters Cdr1p and Cdr2p. The relative importance of each transporter protein for efflux-mediated resistance in
C. albicans
, however, is unknown; neither the relative amounts of each polypeptide in resistant isolates nor their contributions to efflux function have been determined. We have exploited the pump-specific properties of two antibody preparations, and specific pump inhibitors, to determine the relative expression and functions of Cdr1p and Cdr2p in 18 clinical
C. albicans
isolates. The antibodies and inhibitors were standardized using recombinant
Saccharomyces cerevisiae
strains that hyper-express either protein in a host strain with a reduced endogenous pump background. In all 18
C. albicans
strains, including 13 strains with reduced FLC susceptibilities, Cdr1p was present in greater amounts (2- to 20-fold) than Cdr2p. Compounds that inhibited Cdr1p-mediated function, but had no effect on Cdr2p efflux activity, significantly decreased the resistance to FLC of seven representative
C. albicans
isolates, whereas three other compounds that inhibited both pumps did not cause increased chemosensitization of these strains to FLC. We conclude that Cdr1p expression makes a greater functional contribution than does Cdr2p to FLC resistance in
C. albicans
.
Quantitative Real-Time Reverse Transcription-PCR Analysis Reveals Stable and Prolonged Neurotoxin Cluster Gene Activity in a
Clostridium botulinum
Type E Strain at Refrigeration Temperature
Authors: Chen Ying , Korkeala Hannu , Lindén Jere , Lindström Miia
Published: August 2008

The relative expression levels of six botulinum neurotoxin cluster genes in a group II
Clostridium botulinum
type E strain grown at 10 or 30°C were investigated using quantitative real-time reverse transcription-PCR. An enzyme-linked immunosorbent assay was used to confirm neurotoxin expression. Distinct mRNA and toxin production patterns were observed at the two temperatures. The average relative mRNA levels at 10°C were higher than (
ntnh
and
p47
), similar to (
botE
), or lower than (
orfx1
,
orfx2
,
orfx3
) those at 30°C. The maximum
botE
expression levels and average neurotoxin levels at 10°C were 45 to 65% of those at 30°C. The relative mRNA levels at 10°C declined generally slowly within 8 days, as opposed to the rapid decline observed at 30°C within 24 h. Distinct expression patterns of the six genes at the two temperatures suggest that the type E neurotoxin cluster genes are transcribed as two tricistronic operons at 30°C, whereas at 10°C monocistronic (
botE
or
orfx1
alone) and bicistronic (
ntnh
-
p47
and
orfx2
-
orfx3
) transcription may dominate. Thus, type E botulinum neurotoxin production may be involved with various temperature-dependent regulatory events. In light of group II
C. botulinum
type E being a dangerous food-borne pathogen, these findings may be important in terms of the safety of refrigerated packaged foods of extended durability.
Differential Effects of Temperature on Natural Transformation to Erythromycin and Nalidixic Acid Resistance in
Campylobacter coli
Authors: Kim Joo-Sung , Kim Jae-Won , Kathariou S.
Published: August 2008

Campylobacter jejuni
and
Campylobacter coli
are naturally competent, but limited information exists on the impact of environmental conditions on transformation. In this study, we investigated the impact of temperature and microaerobic versus aerobic atmosphere on transformation of
C. coli
to erythromycin and nalidixic acid resistance. Frequency of transformation was not significantly different between microaerobic (5 to 10% CO
2
) and aerobic conditions. However,
C. coli
was transformed to erythromycin resistance at a significantly higher frequency at 42°C than at 25°C (
P
< 0.05), and few or no transformants were obtained at 25°C. In contrast, transformation to nalidixic acid resistance was highly efficient at both 42°C and 25°C and was similar or, at the most, fourfold higher at 42°C than at 25°C. DNase I treatment experiments suggested that steps both prior and subsequent to internalization of DNA were influenced by temperature in the case of transformation of
C. coli
to erythromycin resistance. However, the moderately increased (fourfold) frequency of transformation to nalidixic acid resistance at 42°C compared to that at 25°C was exclusively associated with steps prior to DNA internalization. These findings suggest that transformation to erythromycin resistance may be significantly more frequent in the gastrointestinal tract of hosts such as poultry (at 42°C) than in other habitats characterized by lower temperatures, whereas transformation to nalidixic acid resistance may be highly efficient both within and outside the animal hosts.
Climate Patterns Governing the Presence and Permanence of Salmonellae in Coastal Areas of Bahia de Todos Santos, Mexico
Authors: Simental Lourdes , Martinez-Urtaza Jaime
Published: August 2008

Despite the importance of salmonellae as one of the major causes of food-borne infections worldwide, data regarding the presence of these organisms in the environment are limited. We investigated the presence of
Salmonella
spp. in Bahia de Todos Santos (Baja California, Mexico) and evaluated the environmental factors that affect the occurrence of
Salmonella
spp. in this arid region. A total of 1,331 samples collected from 21 sites along the coast during a period of 3 years were analyzed for
Salmonella
spp. Geographical and seasonal distribution of
Salmonella
spp. was evaluated in association with environmental parameters and with human infections in the area. The incidence of
Salmonella
bacteria throughout the study was 4.8%, with the highest incidence detected in wastewater (16.2%), followed by stream water (10.6%), mollusks (7.4%), and seawater (2.3%). Twenty different serotypes were identified among the 64
Salmonella
isolates. The dominant serotype was Typhimurium (23.4%), followed by Vejle (6.2%). The presence of
Salmonella
spp. in coastal areas was mostly confined to rainy periods and areas of stream discharges, and runoff was identified as the predominant factor influencing the transport of
Salmonella
bacteria from source points to the sea via streams. Isolation of
Salmonella
spp. was negatively and significantly associated with temperature, probably because of the effect of solar radiation in the decline of permanence of
Salmonella
bacteria. Conversely, human infections prevailed during the warmest months and were negatively correlated with the presence of
Salmonella
spp. in the marine environment.
Amplification of Uncultured Single-Stranded DNA Viruses from Rice Paddy Soil
Authors: Kim Kyoung-Ho , Chang Ho-Won , Nam Young-Do , Roh Seong Woon , Kim Min-Soo , Sung Youlboong , Jeon Che Ok , Oh Hee-Mock , Bae Jin-Woo
Published: August 2008

Viruses are known to be the most numerous biological entities in soil; however, little is known about their diversity in this environment. In order to explore the genetic diversity of soil viruses, we isolated viruses by centrifugation and sequential filtration before performing a metagenomic investigation. We adopted multiple-displacement amplification (MDA), an isothermal whole-genome amplification method with φ29 polymerase and random hexamers, to amplify viral DNA and construct clone libraries for metagenome sequencing. By the MDA method, the diversity of both single-stranded DNA (ssDNA) viruses and double-stranded DNA viruses could be investigated at the same time. On the contrary, by eliminating the denaturing step in the MDA reaction, only ssDNA viral diversity could be explored selectively. Irrespective of the denaturing step, more than 60% of the soil metagenome sequences did not show significant hits (E-value criterion, 0.001) with previously reported viral sequences. Those hits that were considered to be significant were also distantly related to known ssDNA viruses (average amino acid similarity, approximately 34%). Phylogenetic analysis showed that replication-related proteins (which were the most frequently detected proteins) related to those of ssDNA viruses obtained from the metagenomic sequences were diverse and novel. Putative circular genome components of ssDNA viruses that are unrelated to known viruses were assembled from the metagenomic sequences. In conclusion, ssDNA viral diversity in soil is more complex than previously thought. Soil is therefore a rich pool of previously unknown ssDNA viruses.
Syntrophic Growth on Formate: a New Microbial Niche in Anoxic Environments
Authors: Dolfing Jan , Jiang Bo , Henstra Anne M. , Stams Alfons J. M. , Plugge Caroline M.
Published: August 2008

Anaerobic syntrophic associations of fermentative bacteria and methanogenic archaea operate at the thermodynamic limits of life. The interspecies transfer of electrons from formate or hydrogen as a substrate for the methanogens is key. Contrary requirements of syntrophs and methanogens for growth-sustaining product and substrate concentrations keep the formate and hydrogen concentrations low and within a narrow range. Since formate is a direct substrate for methanogens, a niche for microorganisms that grow by the conversion of formate to hydrogen plus bicarbonate—or vice versa—may seem unlikely. Here we report experimental evidence for growth on formate by syntrophic communities of (i)
Moorella
sp. strain AMP in coculture with a thermophilic hydrogen-consuming
Methanothermobacter
species and of (ii)
Desulfovibrio
sp. strain G11 in coculture with a mesophilic hydrogen consumer,
Methanobrevibacter arboriphilus
AZ. In pure culture, neither
Moorella
sp. strain AMP, nor
Desulfovibrio
sp. strain G11, nor the methanogens grow on formate alone. These results imply the existence of a previously unrecognized microbial niche in anoxic environments.
High and Low Temperatures Differently Affect Infection Density and Vertical Transmission of Male-Killing
Spiroplasma
Symbionts in
Drosophila
Hosts
Authors: Anbutsu Hisashi , Goto Shunsuke , Fukatsu Takema
Published: August 2008

We investigated the vertical transmission, reproductive phenotype, and infection density of a male-killing
Spiroplasma
symbiont in two
Drosophila
species under physiological high and low temperatures through successive host generations. In both the native host
Drosophila nebulosa
and the nonnative host
Drosophila melanogaster
, the symbiont infection and the male-killing phenotype were stably maintained at 25°C, rapidly lost at 18°C, and gradually lost at 28°C. In the nonnative host, both the high and low temperatures significantly suppressed the infection density of the spiroplasma. In the native host, by contrast, the low temperature suppressed the infection density of the spiroplasma whereas the high temperature had little effect on the infection density. These results suggested that the low temperature suppresses both the infection density and the vertical transmission of the spiroplasma whereas the high temperature suppresses the vertical transmission preferentially. The spiroplasma density was consistently higher in the native host than in the nonnative host, suggesting that the host genotype may affect the infection density of the symbiont. The temperature- and genotype-dependent instability of the symbiont infection highlights a complex genotype-by-genotype-by-environment interaction and may be relevant to the low infection frequencies of the male-killing spiroplasmas in natural
Drosophila
populations.
Identification of the Putative Protein Phosphatase GenePTC1as a Virulence-Related Gene Using a Silkworm Model ofCandida albicansInfection
Authors: Hanaoka Nozomu , Takano Yukie , Shibuya Kazutoshi , Fugo Hajime , Uehara Yoshimasa , Niimi Masakazu
Published: August 2008

Protein phosphatases are critical for the regulation of many cellular processes. Null mutants of 21 putative protein phosphatases ofCandida albicanswere constructed by consecutive allele replacement using theURA3andARG4marker genes. A simple silkworm model ofC. albicansinfection was used to screen the panel of mutants. Four null mutant (cmp1Δ,yvh1Δ,sit4Δ, andptc1Δ) strains showed attenuated virulence in the silkworm model relative to that of control and parental strains. Three of the mutants, thecmp1Δ,yvh1Δ, andsit4Δ mutants, had previously been identified as affecting virulence in a conventional mouse model, indicating the validity of the silkworm model screen. Disruption of the putative protein phosphatase genePTC1ofC. albicans, which has 52% identity to theSaccharomyces cerevisiaetype 2C protein phosphatasePTC1, significantly reduced virulence in the silkworm model. The mutant was also avirulent in a mouse model of disseminated candidiasis. Reintroducing either of theC. albicans PTC1alleles into the disruptant strain, using a cassette containing either allele under the control of a constitutiveACT1promoter, restored virulence in both infection models. Characterization ofptc1Δ revealed other phenotypic traits, including reduced hyphal growth in vitro and in vivo, and reduced extracellular proteolytic activity. We conclude thatPTC1may contribute to pathogenicity inC. albicans.
Anoxia-Induced Suspended Animation in Budding Yeast as an Experimental Paradigm for Studying Oxygen-Regulated Gene Expression
Authors: Chan Kin , Roth Mark B.
Published: August 2008

A lack of oxygen can force many organisms to enter into recoverable hypometabolic states. To better understand how organisms cope with oxygen deprivation, our laboratory previously had shown that when challenged with anoxia, both the nematode
Caenorhabditis elegans
and embryos of the zebrafish
Danio rerio
enter into suspended animation, in which all life processes that can be observed by light microscopy reversibly halt pending the restoration of oxygen (P. A. Padilla and M. B. Roth, Proc. Natl. Acad. Sci. USA 98:7331-7335, 2001, and P. A. Padilla, T. G. Nystul, R. A. Zager, A. C. Johnson, and M. B. Roth, Mol. Biol. Cell 13:1473-1483, 2002). Here, we show that both sporulating and vegetative cells of the budding yeast
Saccharomyces cerevisiae
also enter into a similar state of suspended animation when made anoxic on a nonfermentable carbon source. Transcriptional profiling using cDNA microarrays and follow-on quantitative real-time PCR analysis revealed a relative derepression of aerobic metabolism genes in carbon monoxide (CO)-induced anoxia when compared to nitrogen (N
2
) gas-induced anoxia, which is consistent with the known oxygen-mimetic effects of CO. We also found that mutants deleted for components of the mitochondrial retrograde signaling pathway can tolerate prolonged exposure to CO but not to N
2
. We conclude that the cellular response to anoxia is dependent on whether the anoxic gas is an oxygen mimetic and that the mitochondrial retrograde signaling pathway is functionally important for mediating this response.
Transcriptome for Photobiological Hydrogen Production Induced by Sulfur Deprivation in the Green Alga
Chlamydomonas reinhardtii
Authors: Nguyen Anh Vu , Thomas-Hall Skye R. , Malnoë Alizée , Timmins Matthew , Mussgnug Jan H. , Rupprecht Jens , Kruse Olaf , Hankamer Ben , Schenk Peer M.
Published: August 2008

Photobiological hydrogen production using microalgae is being developed into a promising clean fuel stream for the future. In this study, microarray analyses were used to obtain global expression profiles of mRNA abundance in the green alga
Chlamydomonas reinhardtii
at different time points before the onset and during the course of sulfur-depleted hydrogen production. These studies were followed by real-time quantitative reverse transcription-PCR and protein analyses. The present work provides new insights into photosynthesis, sulfur acquisition strategies, and carbon metabolism-related gene expression during sulfur-induced hydrogen production. A general trend toward repression of transcripts encoding photosynthetic genes was observed. In contrast to all other
LHCBM
genes, the abundance of the
LHCBM9
transcript (encoding a major light-harvesting polypeptide) and its protein was strongly elevated throughout the experiment. This suggests a major remodeling of the photosystem II light-harvesting complex as well as an important function of
LHCBM9
under sulfur starvation and photobiological hydrogen production. This paper presents the first global transcriptional analysis of
C. reinhardtii
before, during, and after photobiological hydrogen production under sulfur deprivation.
Shr Is a Broad-Spectrum Surface Receptor That Contributes to Adherence and Virulence in Group A Streptococcus
Authors: Fisher Morly , Huang Ya-Shu , Li Xueru , McIver Kevin S. , Toukoki Chadia , Eichenbaum Zehava
Published: August 2008

Group A streptococcus (GAS) is a common hemolytic pathogen that produces a range of suppurative infections and autoimmune sequelae in humans. Shr is an exported protein in GAS, which binds in vitro to hemoglobin, myoglobin, and the hemoglobin-haptoglobin complex. We previously reported that Shr is found in association with whole GAS cells and in culture supernatant. Here, we demonstrate that cell-associated Shr could not be released from the bacteria by the muralytic enzyme mutanolysin and was instead localized to the membrane. Shr was available, however, on the exterior of GAS, exposed to the extracellular environment. In vitro binding and competition assays demonstrated that in addition to hemoprotein binding, purified Shr specifically interacts with immobilized fibronectin and laminin. The absence of typical fibronectin-binding motifs indicates that a new protein pattern is involved in the binding of Shr to the extracellular matrix. RecombinantLactococcus lactiscells expressing Shr on the bacterial surface gained the ability to bind to immobilized fibronectin, suggesting that Shr can function as an adhesin. The inactivation ofshrresulted in a 40% reduction in the attachment to human epithelial cells in comparison to the parent strain. GAS infection elicited a high titer of Shr antibodies in sera from convalescent mice, demonstrating that Shr is expressed in vivo. Theshrmutant was attenuated for virulence in an intramuscular zebrafish model system. In summary, this study identifies Shr as being a new microbial surface component recognizing adhesive matrix molecules in GAS that mediates attachment to epithelial cells and contributes to the infection process.
Chlamydial Effector Proteins Localized to the Host Cell Cytoplasmic Compartment
Authors: Kleba Betsy , Stephens Richard S.
Published: August 2008

Disease-causing microbes utilize various strategies to modify their environment in order to create a favorable location for growth and survival. Gram-negative bacterial pathogens often use specialized secretion systems to translocate effector proteins directly into the cytosol of the eukaryotic cells they infect. These bacterial proteins are responsible for modulating eukaryotic cell functions. Identification of the bacterial effectors has been a critical step toward understanding the molecular basis for the pathogenesis of the bacteria that use them. Chlamydiae are obligate intracellular bacterial pathogens that have a type III secretion system believed to translocate virulence effector proteins into the cytosol of their host cells. Selective permeabilization of the eukaryotic cell membrane was used in conjunction with metabolic labeling of bacterial proteins to identify chlamydial proteins that localize within the cytosol of infected cells. More than 20Chlamydia trachomatisandC. pneumoniaeproteins were detected within the cytoplasmic compartment of infected cells. While a number of cytosolic proteins were shared, others were unique to each species, suggesting that variation among cytosolic chlamydial proteins contributes to the differences in the pathogenesis of the chlamydial species. The spectrum of chlamydial proteins exported differed concomitant with the progress of the developmental cycle. These data confirm that a dynamic relationship exists betweenChlamydiaand its host and that translocation of bacterial proteins into the cytosol is developmentally dependent.
Integrative Conjugative Elements and Related Elements Are Major Contributors to the Genome Diversity ofStreptococcus agalactiae
Authors: Brochet Mathieu , Couvé Elisabeth , Glaser Philippe , Guédon Gérard , Payot Sophie
Published: August 2008

Thirty-five putative integrative conjugative elements and related elements were identified at 15 locations in the eight sequenced genomes ofStreptococcus agalactiae. Twelve are composite, likely resulting from site-specific accretions. Circular forms were detected for five elements. Macroarray analysis confirmed their high plasticity and wide distribution inS. agalactiae.
Interaction of Penicillin-Binding Protein 2 with Soluble Lytic Transglycosylase B1 inPseudomonas aeruginosa
Authors: Legaree Blaine A. , Clarke Anthony J.
Published: August 2008

Soluble lytic transglycosylase B1 fromPseudomonas aeruginosawas coupled to Sepharose and used to immobilize interaction partners from membrane protein extracts. Penicillin-binding protein 2 (PBP2) was identified as a binding partner, suggesting that the two proteins function together in the biosynthesis of peptidoglycan. By use of an engineered truncated derivative, the N-terminal module of PBP2 was found to confer the binding properties.
Search for critical slip surfaces based on finite element method
Authors: Zou Jin-Zhang , Williams David J. , Xiong Wen-Lin
Published: August 2008

In this paper, finite element methods (FEM) are used to determine local shear strength mobilization ratios within a slope and to indicate the probable location of the critical slip surface. To locate the critical slip surface and hence determine the minimum factor of safety, an improved dynamic programming method (IDPM) is employed, in which possible slip surfaces, which must pass between state points, may pass both between and along stages. The IDPM is coupled with an expression for the factor of safety for which the stresses are obtained from the FEM. The results obtained using the FEM–IDPM, for a homogeneous slope and for a test embankment on soft Bangkok clay, have been compared with those observed and obtained using the traditional finite element method and the generalized limit equilibrium wedge method. The FEM–IDPM has the advantage over limit equilibrium methods that the strain- and time-dependent behaviour of soil and the staged construction of the slope can be modelled. Key words : critical slip surface, dynamic programming, factor of safety, finite element method, limit equilibrium method, slope stability.
Simplified design methods for pipelines subject to transverse and longitudinal soil movements
Authors: Rajani B.B. , Robertson P.K. , Morgenstern N.R.
Published: August 2008

Pipelines are often subjected to transverse and longitudinal movements due to displacements in the ground caused by landslides. As landslide movements develop, pipelines can undergo transverse and longitudinal displacements and the resistance offered by the surrounding soil steadily increases depending on the soil characteristics. This resistance reaches an ultimate as the soil reaches failure and develops plastic strains. Two simple analytical solutions have been developed based on this concept: one for transverse movements and another for longitudinal movements. Nondimensional relationships have been developed and are presented in the form of charts. These charts permit hand calculations and rapid verification of structural design of the pipeline and, thus, assess the integrity of existing pipelines located in areas with ground instability. A knowledge of the soil strength and subgrade modulus is required along with pipeline geometry and pipe stiffness to apply the nondimensional relationships. The soil parameters can be measured in situ or estimated using empirical correlations. Worked examples are given to illustrate the proposed methods and to show how various pipe failure criteria can be included. Key words : pipelines, landslide, transverse and longitudinal movements, design method.
THE POLYHEDRAL DISEASE OF THE SPRUCE BUDWORM,CHORISTONEURA FUMIFERANA(CLEM.) (LEPIDOPTERA: TORTRICIDAE)
Authors: Bergold G. H.
Published: August 2008

In investigations of the polyhedral disease of the spruce budworm, the polyhedral bodies have been purified and the isolated virus rods described. Quantitative infection tests indicate a high resistance or immunity of the insects against the virus. Some remarks are made regarding epizootiology.
SOME EFFECTS OF TEMPERATURE ACCLIMATIZATION ON THE CHEMICAL CONSTITUTION OF GOLDFISH TISSUES
Authors: Hoar William S. , Cottle Merva K.
Published: August 2008

The water content of goldfish maintained at 5°, 15°, 20°, and 35 °C. varied directly and the lipid content varied inversely with the change in acclimatization temperature. The cholesterol: fatty acid ratio varied directly and the cholesterol: phospholipid ratio varied inversely with the water content and the temperature of acclimatization. The iodine value changed by 0.51 point per centigrade degree increase in acclimatization temperature These changes are discussed in relation to thermal tolerance and temperature death in poikilotherms.
A NEW APPARATUS FOR THE STUDY OF SEDIMENTATION IN LAKES
Authors: Kleerekoper Herman
Published: August 2008

An apparatus is described for the quantitative study of sedimentation at different levels in lakes. A tray of 1 sq. meter area receives the descending material. This tray can be tightly closed before lifting it from the water, by means of a hydraulic device. Because of the large area and very low borders (5 cm.), the collecting error produced by narrow deep vessels is avoided. Even in oligotrophic lakes, enough material can be collected during one week for microchemical analysis.
PSEUDOCRUZIA (OXYUROIDEA: KATHLANIIDAE) A NEW GENUS OF NEMATODE FROM DOMESTIC SWINE IN INDIA
Authors: Wolfgang R. W.
Published: August 2008

Cruzia orientalis described from pigs in India is re-examined and after comparison with other species of Cruzia, all of which occur in American hosts, it is made the type of a new genus, Pseudocruzia.
THE EFFECT OF INSECTICIDES ON THE ACTION POTENTIALS OF INSECT NERVE
Authors: Lalonde D. I. V. , Brown A. W. A.
Published: August 2008

Solutions of 17 insecticides in corn oil were applied to the leg of Periplaneta americana (L), and their effect on the sensory impulses of the crural nerve was determined by means of a preamplifier and cathode-ray oscillograph. DDT, methoxychlor, and DDD induced well-marked trains of repetitive discharge. Aldrin and dieldrin evoked low-voltage trains of repetitive discharge after a latent period of two to four hours. Technical chlordane, heptachlor, α-chlordan, β-chlordan, and toxaphene all showed considerable latent periods before stimulating the action potentials. Lindane rapidly induced the appearance of tiny sets of repeat spikes. The pyrethrins increased the frequency of impulses, while the dinitro compounds increased both the voltage and frequency. Schradan showed no effect, TEPP a transient stimulation, while parathion induced trains of repetitive discharge after a latent period of three hours.
DISEASE AS A CONTROL OF A POPULATION OF BLUE GROUSE, DENDRAGAPUS OBSCURUS FULIGINOSUS (RIDGWAY)
Authors: Bendell J. F.
Published: August 2008

A population of blue grouse was studied on its summer range at Quinsam Lake, Vancouver Island, to determine the factors of importance in population control. The population is stable with a density of 0.40 adult males and 0.78 yearling and adult females to the acre. A life table is constructed on the basis of a stable population, the death of 80% of the chicks in the first three months after hatch, and the death of 31% of the adults each year, as calculated from banding returns. The survivorship curve is negatively "J"-shaped. Mortality rates appear constant and independent of age after the first year of life. Space, weather, food, predators, and disease are considered as factors capable of population control. Six parasites are new records in this host. Two of the six, Plagiorhynchus formosus and Dispharynx nasuta occur commonly and almost exclusively in the chicks, where they cause extreme damage to the tissues of the gut. It is concluded that parasitism by these helminths is an important mortality factor in the chicks and a major cause of population stability—an equilibrium between death in the older age classes and replacement by surviving young.
STUDIES ON THE LIFE CYCLES AND MORPHOLOGY OF THE LARVAL STAGES OF ALARIA ARISAEMOIDES AUGUSTINE AND URIBE, 1927 AND ALARIA CANIS LARUE AND FALLIS, 1936 (TREMATODA: DIPLOSTOMIDAE)
Authors: Pearson J. C.
Published: August 2008

A. arisaemoides and A. canis have three-host life cycles. In both species there is a mesocercarial stage interpolated between the cercarial and the metacercarial stages. The mesocercaria develops in the second intermediate host and is infective for the definitive host. In the lungs of the definitive host the mesocercariae develops into a diplostomulum which in turn develops into an adult in the small intestine. Mesocercariae survive without developing further in a variety of paratenic hosts, for example, certain frogs, snakes, birds, and mammals. The morphology of the larval stages and the intramolluscan generations is described and observations on the following are given: rate of development, hatching of the egg, and swimming of the miracidium of A. arisaemoides; route of emergence from the snail host, variations in emergence, time of emergence and numbers emerging, activity, and penetration of the second intermediate host by the cercariae; and locomotion and the change in distribution of the mesocercariae of A. arisaemoides and A. canis during metamorphosis of the tadpole host; and egg production by the adult of A. canis.
STUDIES ON THE GENUS KALICEPHALUS (NEMATODA: DIAPHANOCEPHALIDAE): I. ON THE LIFE HISTORIES OF THE NORTH AMERICAN SPECIES K. PARVUS, K. AGKISTRODONTIS, AND K. RECTIPHILUS
Authors: Schad G. A.
Published: August 2008

The life histories of Kalicephalus parvus, K. agkistrodontis, and K. rectiphilus were investigated experimentally. Differences between the three species are noted in histotropism and rate of development. The parasitic third stage of K. parvus is given special attention, as is the development of its genital and spicular primordia. Infection per os was successful in all three species. Skin penetration may also occur. The mode of infection in nature is discussed.
REVISION OF THE GENUS FORCIPOMYIA BASED ON CHARACTERS OF ALL STAGES (DIPTERA, CERATOPOGONIDAE)
Authors: Saunders L. G.
Published: August 2008

Systematists have experienced difficulty in splitting the large genus Forcipomyia into manageable groups on adult characters. The early stages in conjunction with the adults furnish a sound basis on which eight subgenera are established with description of 19 species, 17 of which are new.
A TECHNIQUE FOR ESTIMATING THE FECUNDITY OF NATURAL POPULATIONS OF THE SPRUCE BUDWORM
Authors: Miller C. A.
Published: August 2008

In a severe infestation late-instar spruce budworm larvae that normally feed on current foliage may be forced to complete development on old foliage. This results in a reduction in fecundity. The precise causes of this reduction are not known, but factors that may be involved are the amount and the age of the old foliage consumed. The relationship of pupal case size and fecundity is used as a basis for estimating the expected fecundity in a natural population under these conditions of partial larval starvation. Three regression equations applicable to conditions on the Green River area, New Brunswick, are presented. An index of the actual increase of a population is obtained from an E/F ratio. Ratios may be compared in order to indicate some aspects of oviposition. Actual and expected egg populations can also be compared, subject to certain limitations, to indicate some aspects of adult dispersal. The mean number of eggs per mass in relation to degree of infestation and a simplified method of counting eggs per mass are also discussed.
THE GROSS AND MICROSCOPIC ANATOMY OF THE DIGESTIVE TRACT OF THE OYSTER CRASSOSTREA VIRGINICA (GMELIN)
Authors: Shaw Barbara L. , Battle Helen I.
Published: August 2008

The gross and microscopic anatomy of the digestive tract of Crassostrea virginica (Gmelin), the common oyster of commerce of the North Atlantic Coast, is described. The dorsoventrally compressed mouth bounded by two pairs of labial palps leads into a crescentic oesophagus, thence to the anterior chamber of the stomach from which a complex caecum extends into anteriorly and posteriorly directed spiral appendices. The posterior chamber of the stomach bears a chondroid gastric shield and leads into an elongated chamber which is incompletely divided by two typhlosoles into a style-sac and mid-gut. The intestine is divisible into ascending, median, and descending limbs, the latter merging into the rectum which terminates on the dorsal surface of the adductor muscle. Extensively branched tubular digestive diverticula exit from the stomach by a series of ducts along the margin of the caecum and the posterior stomach. The complete digestive tract is lined by a simple columnar epithelium which is ciliated throughout with the exception of the upper lip or fused external palps, the lower side of the gastric shield in the posterior stomach, and the tubules of the digestive diverticula. Mucous secreting and eosinophilic epithelial cells occur in varying numbers along the course of the tract. Phagocytes are present between the lining epithelial cells, among the peripheral collagenous and muscle fibers, as well as in the lumen of the tract. The gastric shield is shown to be intimately attached to the underlying epithelium by a central clip as well as by minute cytoplasmic processes. The anatomical relationships are compared with various lamellibranchs including the Chilean oyster, Ostrea chilensis Philippi; the European oyster, Ostrea edulis L.; and the Portuguese oyster, Gryphea angulata Lamarck.
THE METAZOAN PARASITES OF THE HETEROSOMATA OF THE GULF OF ST. LAWRENCE: I. ECHINORHYNCHUS LAURENTIANUS SP. NOV. (ACANTHOCEPHALA: ECHINORHYNCHIDAE)
Authors: Ronald Keith
Published: August 2008

Echinorhynchus laurentianus sp. nov. (Acanthocephala: Echinorhynchidae) is described from Hippoglossoides platessoides, Hippoglossus hippoglossus, Pseudopleuronectes americanus, and Scophthalmus aquosus from the Gulf of St. Lawrence.
BIOLOGY OF OTODECTES CYNOTIS, THE EAR CANKER MITE OF CARNIVORES
Authors: Sweatman Gordon K.
Published: August 2008

The life history of Otodectes cynotis has been observed in vitro and all stages in the cycle described. Mites from the dog, cat, fox, and ferret have been shown to be biologically and morphologically identical, and the varietal names of canis, cati, and furonis are invalidated. Other Carnivora also appear to be potential hosts.
STUDIES ON MYTILUS EDULIS L. OF THE "CALANUS" EXPEDITIONS TO HUDSON BAY AND UNGAVA BAY
Authors: Lubinsky I.
Published: August 2008

The "Calanus" expeditions of the Fisheries Research Board of Canada give the first detailed data on the distribution of Mytilus edulis L. in Ungava Bay, Hudson Strait, and the northern part of the Hudson Bay. Types of shells of this mollusc and their growth in the above regions are described. The comparison of the growth of M. edulis from Canadian Eastern Arctic, west Greenland, and the northwestern shores of the Atlantic Ocean shows that northward from the Canadian Maritime Provinces the growth of M. edulis slows down. In the region investigated by "Calanus", growth diminishes from Ungava Bay to Hudson Bay. The dependence of the distribution of M. edulis on the types of water masses and its relation to the northern limits of the subarctic zone in the Canadian Eastern Arctic is discussed.
THE EFFECTS OF TEMPERATURE ON THE DEVELOPMENT OF THE FREE-LIVING STAGES OF DOCHMOIDES STENOCEPHALA (RAILLIET, 1884) (ANCYLOSTOMIDAE: NEMATODA)
Authors: Gibbs H. C. , Gibbs K. E.
Published: August 2008

The effects of temperature on the development of the free-living stages of Dochmoides stenocephala (Railliet, 1884) have been studied using agar cultures. Development was obtained at as low a temperature as 7.5 °C. The optimum temperature for the free-living stages was considered to be 20 °C. The time of development of the larvae to the infective stage was inversely proportional to the ambient temperature between the limits of 7.5 °C and 27 °C.
CHROMATOGRAPHIC FRACTIONATION OF THE NON-DIALYZABLE PORTION OF MOSQUITO EXTRACT AND INTRACUTANEOUS REACTIONS OF MOSQUITO-BITE-SENSITIVE SUBJECTS TO THE SEPARATED COMPONENTS
Authors: McKiel J. A. , Clunie J. C.
Published: August 2008

An extract of each of Aedes aegypti (L.), A. atropalpus (Coq.), and Culex pipiens (L.) was shown by paper chromatography to contain 12 ninhydrin-staining peptides. None of these peptides from the A. aegypti extract was capable of eliciting skin reactions in a volunteer sensitive to A. aegypti bites. A reaction equivalent to that caused by a mosquito bite was produced by an estimated 10−3 g of dialyzed A. aegypti extract from which the ninhydrin-staining peptides had been removed. Of the solvents tested in attempting to fractionate this active material, the most suitable was 65% acetone. By this means, A. aegypti extract was shown to contain at least four fractions capable of producing skin reactions in volunteers sensitive to A. aegypti bites.
DIURNAL BEHAVIOR AND BITING HABITS OF BLACK FLIES (DIPTERA: SIMULIIDAE) IN THE FORESTS OF QUEBEC
Authors: Wolfe L. S. , Peterson D. G.
Published: August 2008

Studies in the region of Baie Comeau, Quebec, from 1954 to 1956, showed that black flies were most active in the morning 1 to 2 hours after dawn and in the evening [Formula: see text] to 1 hour before sunset. Flight activity appeared to depend on light intensity if the temperature was not below 45° F, the wind velocity not above 2 m.p.h., and the relative humidity not below 50%. In the morning, activity was greatest at higher levels of light intensity, i.e., 20 ft-c, than in the evening, 5 ft-c. Activity increased before thunderstorms and rain and the increase appeared related more to the change in light intensity than to changes in atmospheric pressure or humidity. At night, black flies moved to resting places in the tops of the trees, probably because of the more suitable light intensity at the higher levels just before dark. Oviposition commenced in the late afternoon and continued until dark except on overcast days, when it commenced in early afternoon. Simulium (Simulium) venustum Say bit man mainly on the back of the neck.
NEMATODE PARASITES OF VERTEBRATES OF EAST PAKISTAN V. SPIRURID NEMATODES
Authors: Gupta S. P.
Published: August 2008

Viguiera dicrurusi sp. nov. from Dicrurus macrocercus albirctus is described. V. euryoptera Singh, 1949 (not Seurat, 1913) is considered a synonym of V. dicrurusi. A key to the species of the genus Viguiera Seurat, 1913 is given. Redescriptions of Dispharynx nasuta (Rudolphi, 1819) Railliet, Henry, and Sisoff, 1912 from Sturnus c. contra; Torquatella balanocephala Gendre, 1922 from Merops o. orientalis and Castronodus strassenii Singh, 1934 are given. These are all new records from East Pakistan. Dispharynx pavonis Sanwal, 1952 is considered to be a synonym of D. nasuta.
ON THE DEVELOPMENT AND TRANSMISSION OF COSMOCERCOIDES DUKAE OF TERRESTRIAL MOLLUSCS IN ONTARIO
Authors: Anderson Roy C.
Published: August 2008

Nematodes from the mantle cavity of Discus cronkhitei, Zonitoides arborea, and Deroceras gracile, and the rectum of Rana spp., Bufo americanus, and Ambystoma jeffersonianum in Ontario are referred tentatively to Cosmocercoides dukae (Holl, 1928), In molluscs, females deposit third-stage larvae that leave the mantle cavity and appear in slime trails left by snails; when placed on the foot of snails these larvae entered the respiratory pore and went to the mantle cavity where they developed. Larvae were found in the genital tract and ovary of slugs and in eggs of both snails and slugs. These penetrated into the mantle cavity of embryo molluscs which subsequently hatched. All stages of C. dukae can survive for long periods in tap water or invertebrate saline. Females sometimes laid eggs which hatched if they contained a first-stage larva and the latter developed to the infective stage. Worms of all stages from molluscs fed to frogs were passed at intervals in the faeces and there was no evidence this species could establish itself in amphibians; the occurrence of cosmocercids in amphibians in Ontario is possibly the result of the latter eating infected molluscs, the worms being able to survive passage through the gut. The larvae and adults are described in detail herein.
THE PREY OF THE SPIDER LINYPHIA TRIANGULARIS (CLERCK) (ARANEAE, LINYPHIIDAE)
Authors: Turnbull A. L.
Published: August 2008

In a study of the natural foods of the spider, Linyphia triangularis (Clerck), a weekly 3-hour watch of 50 webs was kept from May 1 to October 15. A total of 581 insects representing 153 species entered webs during the observation periods. Most of these were represented by very few individuals, and more than half of the spiders' diet was supplied by about 20 species of prey. Most of the prey were winged adults. Most of the species were present in the community in the adult stage for a short time only. Thus over the season the spider exploited a constantly changing complex of prey species. At any one time the spider relies on a very few species for most of its food. Of all the insects in the community, only those with certain characteristics of distribution, morphology, and behavior are available to the spiders. Suitable characteristics occur in a wide range of distantly related species; thus the spider is not restricted in its prey to any taxonomic group. From the insects that enter the webs the spider exercises some selection. There is a strong suggestion that new or strange species entering a web tend to be rejected on their first few entries, but if they continue to enter they will eventually be accepted.