bluuebunny/crossref_metadata_2025 huggingface dataset:
Kinematic Analysis of Robotic Bevel-Gear Trains
Authors: Freudenstein F. , Longman R. W. , Chen C.-K.
Published: January 2010

A general procedure has been developed for the kinematic analysis of complex bevel-gear trains in which the motion of the arm can be of mobility two or greater (i.e. the arm can rotate about two or more nonparallel, intersecting axes). The analysis of a three-degree-of-freedom gear train used in guiding the motion of the end effector of a recently developed industrial robot is described in detail.
Mechanism Link Rotatability and Limit Position Analysis Using Polynomial Discriminants
Authors: Williams R. L. , Reinholtz C. F.
Published: January 2010

A theory is proposed for algebraically determining the limit positions of single-degree-of-freedom mechanisms. The absence of limit positions indicates that the link being considered is a fully rotating crank. This theory is applied in the present paper to the RSSR and RRSS spatial mechanisms. Conditions for spatial mechanisms analogous to Grashof’s law should be attainable using this theory. A numerical example is given to illustrate the theory.
A General Method of Four-Bar Linkage Mobility Analysis
Authors: Angeles J. , Bernier A.
Published: January 2010

The problem of mobility associated with four-bar linkages is addressed in this paper. The mobility analysis is reduced to finding the global extrema of a quadratic function on a cylinder, which then leads to the geometric problem of finding the intersections of a circle and a hyperbola. The method proposed here produces an efficient mobility analysis that can be readily integrated into any suitable optimization algorithm.
The Global Least-Square Optimization of Function-Generating Linkages
Authors: Angeles J. , Bernier A.
Published: January 2010

As shown elsewhere, the approximate least-square synthesis of function-generating linkages can be formulated in terms of one single decision variable. Hence, functions representing global properties of linkages such as accuracy and transmission quality, which are terms precisely defined in this paper, as well as mobility type, are all functions of one single variable. The optimization procedure presented here is aimed at the synthesis of function-generating linkages with a minimum least-square design error and a maximum transmission quality, while meeting conditions prescribed on the type of mobility (crank or rocker) of its input and/or output links. Alternative performance indices and/or constraints can be treated likewise.
A New Concept in Semi-Active Vibration Isolation
Authors: Alanoly J. , Sankar S.
Published: January 2010

Semi-active suspensions can achieve performance close to that of active suspensions with much lower cost and complexity. They use an active damper in parallel with a passive spring. The forces in the damper are generated merely by the modulation of fluid-flow orifices based on a control scheme involving feedback variables. This paper presents an original control strategy employing only directly measurable variables in vehicle applications. The relative displacement and relative velocity across the suspension are the only feedback signals and the damper force can be continuously modulated (as opposed to on-off control). Vibration isolation performance of the new semi-active scheme is compared to semi-active sky-hook suspension, as well as passive and active suspensions.
Nonlinear Modeling of Kinematic and Flexibility Effects in Manipulator Design
Authors: Naganathan G. , Soni A. H.
Published: January 2010

This paper presents a finite-element-based, nonlinear model to predict the dynamic response of spatial manipulators with flexible links. The methodology takes into account the complete nonlinear coupling effects between the nonlinear gross motion of the links and their deformations due to distributed elasticity. The end-effector performance is predicted for commanded joint motion profiles, when the above nonlinear coupling is taken into account. A simple and efficient finite-element scheme has been developed using a Newton–Euler formulation and Timoshenko Beam Theory. In addition to the spatial manipulators, a particularized methodology is developed for the analysis of planar manipulators. Case studies of both planar and spatial manipulators are presented. Nonlinear kinematic coupling effects are observed to contribute significantly to end-effector positioning errors in flexible manipulator configurations.
A Computer-Aided Design Technique for the Synthesis of Planar Four Bar Mechanisms Satisfying Specified Kinematic and Dynamic Conditions
Authors: Rigelman G. A. , Kramer S. N.
Published: January 2010

This paper presents a computer-aided design optimization method for synthesizing planar four bar mechanisms which satisfy specified kinematic and dynamic conditions. The method can be used for path, motion, and function generation as well as for combinations of these. The kinematic conditions consist of combinations of specifications on the position, velocity, and acceleration of the coupler point and the rotations of the coupler and follower links. The dynamic conditions consist of the minimization of the average power consumed by the mechanism as well as a limit on the maximum input torque. The external loads consist of variable forces and moments at the coupler point as well as variable torques on the follower link. The Selective Precision Synthesis (SPS) method is used to express each kinematic condition in terms of a specification plus an allowable deviation or tolerance from the specification. In this manner, the synthesis problem is converted into a nonlinear optimization problem which is solved using the Generalized Reduced Gradient (GRG) method. In addition, two force balancing routines are included to help the dynamic performance of the mechanism. The mathematical formulation and derivation as well as numerical examples are presented in this paper.
Crowned Spur Gears: Methods for Generation and Tooth Contact Analysis—Part 2: Generation of the Pinion Tooth Surface by a Surface of Revolution
Authors: Litvin F. L. , Zhang J. , Handschuh R. F.
Published: January 2010

A method for generation of crowned pinion tooth surfaces using a surface of revolution is developed. The crowned pinion meshes with a regular involute gear and has a prescribed parabolic type of transmission errors when the gears operate in the aligned mode. When the gears are misaligned the transmission error remains parabolic with the maximum level still remaining very small (less than 0.34 arc second for the numerical examples). Tooth Contact Analysis (TCA) is used to simulate the conditions of meshing, determine the transmission error, and the bearing contact.
A Compact Low-Pressure Drop Desiccant Bed for Solar Air Conditioning Applications: Analysis and Design
Authors: Biswas P. , Kim S. , Mills A. F.
Published: January 2010

Requirements for silica gel desiccant beds used in the “Solar-Desiccant-Evaporative Cooling System” are discussed and the advantages of laminar flow packings demonstrated. An analysis of transient heat and mass transfer in laminar flow silica gel desiccant beds is presented, together with a description of an associated computer code for the solution of the governing partial differential equations. Based on results of calculations using the code, a preliminary design of a prototype scale desiccant bed is developed for a coated sheet packing concept. Results are presented for code calculations used to determine an optimum gel particle size and to explore the effect of substrate thermal capacity on cyclic performance.
Design Method and Performance of Heat Pumps With Refrigerant-Filled Solar Collectors
Authors: O’Dell M. P. , Mitchell J. W. , Beckman W. A.
Published: January 2010

A general procedure is presented for estimating the seasonal performance of solar-assisted heat pumps with refrigerant-filled collectors. The procedure accounts for variations in collector design and orientation and also for heat pump capacity and efficiency. The results from this design procedure for space heating applications are compared against those for both conventional heat pumps and liquid solar systems. The effects of collector area and design, heat pump size and degradation due to cycling, and energy storage are discussed. For space heating, uncovered collector heat pump systems have better performance than both conventional air-source heat pumps and covered collector heat pump systems over a wide range of collector areas. The cooling performance of a collector heat pump system is inferior to that of conventional heat pumps.
Tethered Wind Systems for the Generation of Electricity
Authors: Riegler G. , Riedler W.
Published: January 2010

This report, based on the findings of an Austrian feasibility study, describes balloon-borne tethered wind systems. Latest results and the components of the system are discussed and an outline of the available energy potential is compiled. An overview of economic possibilities is also given.
Mathematical Simulation of Ocean Thermal Energy Conversion Seawater Systems
Authors: Wassel A. T. , Elghobashi S. E. , Potts R. L. , Farr J. L.
Published: January 2010

A mathematical model and computer code have been developed to predict the performance of the Seawater System (SWS) of an Ocean Thermal Energy Conversion (OTEC) power plant. A time-dependent, one-dimensional model is constructed for the fluid flow through the SWS based on the fundamental conservation equations of mass, momentum, and energy. Boundary conditions include system response to seaway dynamics. A finite difference method is used to solve the conservation equations. Auxiliary relations for evaluating friction and heat transfer coefficients and special modeling of sumps and pumps are included. Predictions of OTEC-1 pilot plant performance are presented.
Shell-and-Plate-Type Heat Exchangers for OTEC Plants
Authors: Uehara H. , Kusuda H. , Monde M. , Nakaoka T. , Sumitomo H.
Published: January 2010

New titanium, shell-and-plate type heat exchangers for ocean-thermal-energy-conversion (OTEC) plants have been developed which include three different plate types (fluted, impinging, and porous-surface) for the evaporator and two kinds of plates (No. 1 and No. 2) for the condenser. Performance tests with fresh water show that the overall heat transfer coefficient U of the evaporator using the porous plate is the highest among the three plates; it can reach 4000–4500 W/m2K using ammonia as the working fluid and 3500–4000 W/m2K for a Freon, R-22. The U of the condenser using the No. 2 plate is higher than that using the No. 1 plate; it can reach 3800–4500 W/m2K for ammonia and 2000–3500 W/m2K for R-22.
Second Law Analysis of Solar Powered Absorption Cooling Cycles and Systems
Authors: Anand D. K. , Lindler K. W. , Schweitzer S. , Kennish W. J.
Published: January 2010

The Second Law of Thermodynamics is used to analyze solar powered absorption cooling cycles and systems. Irreversibility is used as a figure of merit for components and cycles. The irreversibility of individual components is determined for several solar-powered absorption cycles and systems. The understanding of the causes of these irreversibilities identifies the areas of possible cycle and system improvements.
Heat Transfer Enhancement in Air-Heating Flat-Plate Solar Collectors
Authors: Liu Ye-Di , Diaz L. A. , Suryanarayana N. V.
Published: January 2010

The efficiency of an air-heating flat-plate solar collector can be increased by reducing the absorber plate temperature by providing it with extended surfaces. An experimental study was conducted to determine the temperature depression and the increase in friction factor, by providing a uniformly heated plate with pin fins. Data were obtained with three spacings of the fins for five mass flow rates of air and two values of heat flux. Significant temperature depressions can be obtained leading to increase in efficiency but these are acompanied by increases in friction factor. Employing different length scales and the concept of pumping power factor, it is shown that the data can be correlated by j = 1.018 Re−0.49 and Nu = 1.03 F0.19.
Utilization of Seasonal Sky Radiation Energy for Space Cooling
Authors: Saitoh T. , Ono T.
Published: January 2010

A unique seasonal collection method of sky radiation energy was proposed. This method is especially effective in the humid area where the radiative cooling could not be expected. To collect the cooling energy for space cooling, the sky radiator is operated from April–June when humidity is much less than in August. The simulation has shown that this long-term shortage system provides sufficient space cooling energy for a standard home. An experiment was carried out with a black-painted sky radiator to obtain data under actual meteorological conditions. The results were then compared with various empirical equations presented hitherto.
Solar-Powered/Fuel-Assisted Rankine Cycle Power and Cooling System: Sensitivity Analysis
Authors: Lior N. , Koai K.
Published: January 2010

The subject of this analysis is a solar power/cooling system based on a novel hybrid steam Rankine cycle. Steam is generated by the use of solar energy collected at about 100°C, and it is then superheated to about 600°C in a fossil-fuel-fired superheater. The addition of about 20–26 percent of energy as fuel doubles the power cycle’s efficiency as compared to organic fluid Rankine cycles operating at similar collector temperatures. A sensitivity analysis of the system’s performance to the size and type of its components was performed by a transient (hourly) computer simulation over the month of August in two representative climatic regions (Washington, D.C. and Phoenix, Ariz.), and led to the description of a system configuration which provides optimal energy performance. The newly designed turbine’s predicted efficiency is seen to be essentially invariant with system configuration, and has a monthly average value of about 73 percent.
Charge and Discharge Characteristics of a Direct Contact Latent Thermal Energy Storage Unit Using Form-Stable High-Density Polyethylene
Authors: Abe Y. , Takahashi Y. , Sakamoto R. , Kanari K. , Kamimoto M. , Ozawa T.
Published: January 2010

For solar thermal energy utilization in relatively low temperatures, a lab-scale direct contact, latent thermal energy storage unit using a form-stable high-density polyethylene (HDPE) was developed. The phase change material (PCM), the form-stable HDPE, does not fluidize nor adhere even after melting, and this particular property permits a direct contact heat transfer between the PCM and a heat transfer fluid (HTF). The storage column in the present study consists of a bundle of vertically arranged thin HDPE rods, where HTF flows in the axial direction and contacts with the HDPE surface directly. A series of experiments were performed for both charge and discharge modes under conditions of different flow rates, initial temperatures in the column, and HTF inlet temperatures. A numerical simulation was also made to study further detailed performance of the storage unit. The charge and discharge characteristics of the storage unit are discussed.
Application of Transparent Enclosure Theory to Solar Energy Absorption by Cylindrical Tubes in Sunspaces
Authors: McCabe M. E. , Van Migom M.
Published: January 2010

A general matrix formulation for beam and diffuse radiative solar transfer is presented for an enclosure containing partially transparent walls. The general theory is used to study the absorption of radiant solar energy in a building sunspace having a south-facing window and a row of opaque vertical cylindrical-tube solar absorbers. A two-dimensional model is formulated for the sunspace in which a typical cylindrical absorber tube is subdivided into a number of uniform elements and the window and sunspace surfaces are each represented as single elements. The matrix expressions are evaluated for incident solar flux conditions typical for a south vertical window on a clear winter day. The results are presented as dimensionless ratios of absorbed-to-incident solar flux as a function of the tube spacing to radius ratio. The spatial distribution of absorbed solar flux is presented at discrete time interals for the cylindrical tube. Space and time-averaged values of absorbed solar flux are also presented for the cylinder, the window, and the room. The potential application of these results for thermal modeling in passive solar applications is discussed.
Dynamic Stall: The Case of the Vertical Axis Wind Turbine
Authors: Laneville A. , Vittecoq P.
Published: January 2010

This paper presents the results of an experimental investigation on a driven Darrieus turbine rotating at different tip speed ratios. For a Reynolds number of 3.8 × 104, the results indicate the presence of dynamic stall at tip speed ratio less than 4, and that helicopter blade aerodynamics can be used in order to explain some aspects of the phenomenon. It was observed that in deep stall conditions, a vortex is formed at the leading edge; this vortex moves over the airfoil surface with 1/3 of the airfoil speed and then is shed at the trailing edge. After its shedding, the vortex can interact with the airfoil surface as the blade passes downstream.
Analysis and Measurements of Interzonal Natural Convection Heat Transfer in Buildings
Authors: Hill D. , Kirkpatrick A. , Burns P.
Published: January 2010

Natural convection heat transfer through doorways can be an important process by which thermal energy is transferred from one zone to another zone of a building. The topic of this paper is interzonal natural convection in a two zone and a three zone multilevel full scale building. Aperture velocity and temperature distributions are measured and the experimental interzonal mass flow rate and heat transfer are determined. A Bernoulli model is derived to predict the neutral heights, velocity profiles, and interzonal heat transfer. The measured and predicted interzonal flow rate and heat transfer are compared and found to be in good agreement.
The Distribution of Concentrated Solar Radiation in Paraboloidal Collectors
Authors: Jeter S. M.
Published: January 2010

A procedure is presented for calculating the distribution of concentrated flux in paraboloidal solar collectors and is applied to idealized and practical cases. This procedure is based on the firmly established concepts of the flux integral and radiant intensity but is implemented by simple geometrical constructions involving infinitesimal pyramids based on the reflecting surface. This procedure yields a formulation well suited for numerical evaluation.
Monthly Averages of the Daily Effective Optical Air Mass and Solar Related Angles for Horizontal or Inclined Surfaces
Authors: Gueymard C.
Published: January 2010

An analytical method is described for calculating the daily averages or effective values of the sun’s elevation, azimuth, hour angle, angle of incidence and air mass. A particular case is considered first and corresponds to the extraterrestrial radiation. The general derivation takes into account atmospheric effects in a simple way, provided that long-term averages of solar radiation are available. Examples of application are given for the climate of Montreal, Canada. In particular, it is shown that monthly averages of beam radiation on the horizontal may be directly converted to normal incidence values (and vice versa) by use of the mean solar elevation.
Design of an Experimental Solar-Powered, Solid-Adsorption Ice Maker
Authors: Pons M. , Guilleminot J. J.
Published: January 2010

Purely thermal heat pumps can be devised with adsorbate/solid adsorbent pairs, for example for refrigeration purposes. As each cycle consists of two periods, i.e., heating/desorption/condensation and cooling/adsorption/evaporation, this mode of operation is well-suited to solar energy. After experiments with the Zeolite/Water pair, a solar-powered ice maker was designed with the Activated Carbon/Methanol pair, and a prototype was built in Orsay. The solar collectors (6 m2) contain, on the whole, 130 kg of A.C., the condensers are air-cooled, and the evaporator has a net production of 30–35 kg of ice per sunny day. The ice is easily removed, and in principle the machine could be automatically operated. The net solar C.O.P. is 0.12, which makes this machine one of the most efficient solar ice makers.
Essential Role of the Histone Methyltransferase G9a in Cocaine-Induced Plasticity
Authors: Maze Ian , Covington Herbert E. , Dietz David M. , LaPlant Quincey , Renthal William , Russo Scott J. , Mechanic Max , Mouzon Ezekiell , Neve Rachael L. , Haggarty Stephen J. , Ren Yanhua , Sampath Srihari C. , Hurd Yasmin L. , Greengard Paul , Tarakhovsky Alexander , Schaefer Anne , Nestler Eric J.
Published: January 2010

Cocaine Addiction and Histone Methylation

Long-lasting behavioral syndromes associated with chronic cocaine exposure may result from dysregulation of the global transcriptional machinery.

Maze
et al.

(p.
213
) observed that histone lysine methylation in the nucleus accumbens plays a critical role in mediating the regulation of gene expression in response to repeated cocaine self-administration. Chronic cocaine was linked to overall reductions in dimethylation of lysine 9 of histone 3 (H3K9) in this brain region. Repressing H3K9 after chronic cocaine administration facilitated reward-related changes in behavior. The authors identifed the methyltransferase G9a as an essential mediator and an important regulator of dendritic spine plasticity. Downregulation of G9a was linked to the transcription factor ΔFosB.
Valuing Common Species
Authors: Gaston Kevin J.
Published: January 2010

Ecologically common species play key roles in terrestrial and marine ecosystems, yet are also the main victims of habitat loss, ecosystem degradation, and overexploitation.
Directing the Centromere Guardian
Authors: Javerzat Jean-Paul
Published: January 2010

Histone phosphorylation controls the chromosomal localization of a protein family that functions in chromosome segregation during cell division.
Scientific Tide on New Wave Stages?

Idiot Savant
written and directed by Richard Foreman

Public Theater, New York. 27 October–20 December 2009. www.publictheater.org

Inside Out
Cirkus Cirkör Music by Irya's Playground Tilde Björfors, director

Brooklyn Academy of Music, New York. 12–15 November 2009. Next Wave Festival. www.bam.org/view.aspx?pid=1269

Kepler
Philip Glass, composer Libretto by Martina Winkel

Brooklyn Academy of Music, New York. 18–21 November 2009. Next Wave Festival. www.bam.org/view.aspx?pid=1271
Authors: Firestein Stuart
Published: January 2010

Although very different, Richard Foreman's play
Idiot Savant
, Cirkus Cirkör's
Inside Out
, and Philip Glass's opera
Kepler
each drew at least some of their themes from science.
Multiplex-PCR Method for Species Identification of Coagulase-Positive Staphylococci
Authors: Sasaki Takashi , Tsubakishita Sae , Tanaka Yoshikazu , Sakusabe Arihito , Ohtsuka Masayuki , Hirotaki Shintaro , Kawakami Tetsuji , Fukata Tsuneo , Hiramatsu Keiichi
Published: January 2010

In veterinary medicine, coagulase-positive staphylococci (CoPS) other than
Staphylococcus aureus
have frequently been misidentified as being
S. aureus
strains, as they have several phenotypic traits in common. There has been no reliable method to distinguish among CoPS species in veterinary clinical laboratories. In the present study, we sequenced the thermonuclease (
nuc
) genes of staphylococcal species and devised a multiplex-PCR (M-PCR) method for species identification of CoPS by targeting the
nuc
gene locus. To evaluate sensitivity and specificity, we used this M-PCR method on 374 staphylococcal strains that had been previously identified to the species level by an
hsp60
sequencing approach. We could successfully distinguish between
S. aureus
,
S. hyicus
,
S. schleiferi
,
S. intermedius
,
S. pseudintermedius
, and
S. delphini
groups A and B. The present method was both sensitive (99.8%) and specific (100%). Our M-PCR assay will allow the routine species identification of CoPS isolates from various animal species for clinical veterinary diagnosis.
Genetic Relationships among Reptilian and Mammalian
Campylobacter fetus
Strains Determined by Multilocus Sequence Typing
Authors: Dingle Kate E. , Blaser Martin J. , Tu Zheng-Chao , Pruckler Janet , Fitzgerald Collette , van Bergen Marcel A. P. , Lawson Andrew J. , Owen Robert J. , Wagenaar Jaap A.
Published: January 2010

Reptile
Campylobacter fetus
isolates and closely related strains causing human disease were characterized by multilocus sequence typing. They shared ∼90% nucleotide sequence identity with classical mammalian
C. fetus
, and there was evidence of recombination among members of these two groups. The reptile group represents a possible separate genomospecies capable of infecting humans.
Comprehensive Analysis of a Norovirus-Associated Gastroenteritis Outbreak, from the Environment to the Consumer
Authors: Le Guyader Françoise S. , Krol Joanna , Ambert-Balay Katia , Ruvoen-Clouet Nathalie , Desaubliaux Benedicte , Parnaudeau Sylvain , Le Saux Jean-Claude , Ponge Agnès , Pothier Pierre , Atmar Robert L. , Le Pendu Jacques
Published: January 2010

Noroviruses have been recognized to be the predominant agents of nonbacterial gastroenteritis outbreaks in humans, and their transmission via contaminated shellfish consumption has been demonstrated. Norovirus laboratory experiments, volunteer challenge studies, and community gastroenteritis outbreak investigations have identified human genetic susceptibility factors related to histo-blood group antigen expression. Following a banquet in Brittany, France, in February 2008, gastroenteritis cases were linked to oyster consumption. This study identified an association of the norovirus illnesses with histo-blood group expression, and oyster contamination with norovirus was confirmed by qualitative and quantitative analyses. The secretor phenotype was associated with illness, especially for the non-A subgroup. The study showed that, in addition to accidental climatic events that may lead to oyster contamination, illegal shellfish collection and trading are also risk factors associated with outbreaks.
Cytotoxic Effects of
Klebsiella oxytoca
Strains Isolated from Patients with Antibiotic-Associated Hemorrhagic Colitis or Other Diseases Caused by Infections and from Healthy Subjects
Authors: Joainig Martina M. , Gorkiewicz Gregor , Leitner Eva , Weberhofer Paul , Zollner-Schwetz Ines , Lippe Irmgard , Feierl Gebhard , Krause Robert , Hinterleitner Thomas , Zechner Ellen L. , Högenauer Christoph
Published: January 2010

Antibiotic-associated hemorrhagic colitis (AAHC) is associated with
Klebsiella oxytoca
. This study analyzed whether cytotoxic properties are linked to specific subtypes of
K. oxytoca. Klebsiella
isolates from stools of AAHC patients, healthy carriers, and diarrhea patients as well as from infections of other organs were investigated. Cytotoxic effects on human epithelial cells were limited to the species
K. oxytoca
and were not detectable for any other
Klebsiella
species. Isolates from AAHC patients and from stools showed the highest proportion of cytotoxic strains. Urinary or respiratory tract isolates exhibited no cytotoxicity. Macrorestriction profiling of strains revealed no genetic relationships of AAHC isolates or the cytotoxic phenotype but identified that different
K. oxytoca
strains with different cytotoxic behaviors may be prevalent in the same AAHC patient. Under laboratory conditions, cytotoxicity was maximally effective after exponential bacterial growth and then declined despite the continued viability of
K. oxytoca
cells in culture. Given its capacity to induce AAHC and that a high proportion of stool isolates tested cytotoxin positive, we argue that
K. oxytoca
should be considered an opportunistic pathogen if detected in stools. The ability to induce disease after antibiotic treatment most likely represents an overgrowth of the toxin-producing bacterium due to an alteration of the normal colonic microflora.
Evaluation of Sensititre Plates for Identification of Clinically Relevant Coagulase-Negative Staphylococci
Authors: Garza-González Elvira , Morfin-Otero Rayo , Macedo Pedro , Gonzalez Gloria M. , Llaca-Díaz Jorge M. , Perez-Gómez Raul , Rodriguez-Noriega Eduardo
Published: January 2010

Coagulase-negative staphylococcus isolates were identified using Sensititre GPID plates and API strips (
n
= 156). For selected isolates, partial sequencing of the 16S rRNA,
sodA
, and
tuf
genes was performed. The Sensititre plates correctly identified 68.9% of isolates, with a concordance of 86% for
Staphylococcus haemolyticus
and 73% for
Staphylococcus epidermidis
.
The p38 Signaling Pathway Upregulates Expression of the Epstein-Barr Virus LMP1 Oncogene
Authors: Johansson Pegah , Jansson Ann , Rüetschi Ulla , Rymo Lars
Published: January 2010

The Epstein-Barr virus (EBV)-encoded LMP1 oncogene has a role in transformation, proliferation, and metastasis of several EBV-associated tumors. Furthermore, LMP1 is critically involved in transformation and growth of EBV-immortalized B cellsin vitro. The oncogenic properties of LMP1 are attributed to its ability to upregulate anti-apoptotic proteins and growth signals. The transcriptional regulation of LMP1 is dependent on the context of cellular and viral proteins present in the cell. Here, we investigated the effect of several signaling pathways on the regulation of LMP1 expression. Inhibition of p38 signaling, using p38-specific inhibitors SB203580 and SB202190, downregulated LMP1 in estrogen-induced EREB2.5 cells. Similarly, p38 inhibition decreased trichostatin A-induced LMP1 expression in P3HR1 cells. Exogenous expression of p38 in lymphoblastoid cell lines (LCLs) led to an increase in LMP1 promoter activity in reporter assays, and this activation was mediated by the previously identified CRE site in the promoter. Inhibition of p38 by SB203580 and p38-specific small interfering RNA (siRNA) also led to a modest decrease in endogenous LMP1 expression in LCLs. Chromatin immunoprecipitation indicated decreased binding of CREB-ATF1 to the CRE site in the LMP1 promoter after inhibition of the p38 pathway in EREB2.5 cells. Taken together, our results suggest that an increase in p38 activation upregulates LMP1 expression. Since p38 is activated in response to stimuli such as stress or possibly primary infection, a transient upregulation of LMP1 in response to p38 may allow the cells to escape apoptosis. Since the p38 pathway itself is activated by LMP1, our results also suggest the presence of an autoregulatory loop in LMP1 upregulation.
The brain and central nervous system of Müller's larva
Authors: Lacalli T. C.
Published: January 2010

The central nervous system of the Müller's larva of Pseudoceros canadensis is described at the ultrastructural level. It comprises at hatching a brain, apical organ, and four nerve cords. The brain has a central neuropile divided into two distinct regions: an apical plexus of interdigitating neurites and a basal commissure from which the nerve cords arise. The brain closely resembles that of polychaete trochophores in a number of structural and organizational features, particularly in its possession of an apical plexus, evidence for a close evolutionary relationship between Müller's larva and the trochophore. The arrangement of nerve cords suggests a fourfold symmetry may be fundamental to the central nervous system in Müller's larva, but determining whether such symmetry is also reflected in the internal organization of the brain will require further study of early brain development.
On the role of pheromones in aggregation formation in camel crickets, Ceuthophilus secretus (Orthoptera: Gryllacrididae)
Authors: Nagel Michael G. , Cade William H.
Published: January 2010

Choice chamber preference tests were used to determine if camel crickets, Ceuthophilus secretus, use pheromones in forming aggregations. Insects occurred significantly more often on choice chamber sides having filter paper scented by exposure to conspecifics than they did on unconditioned filter paper. Insects also formed aggregations significantly more quickly when exposed to conspecifics as opposed to nonconspecific scents in the choice chambers. These data demonstrate that C. secretus use an aggregation pheromone. Insects occurred significantly more often on sides conditioned with ether extracts of whole insect bodies as opposed to unconditioned sides. Insects also occurred significantly more often on filter paper conditioned with abdomen extracts as opposed to unconditioned filter paper, but no preference was shown for extracts from the head and thorax region. These data demonstrate that the abdomen is the generalized site of aggregation pheromone production. Insects which had both antennae removed were unable to form aggregations in response to conspecific scent, thus indicating that the antennae are the site of aggregation pheromone reception.
Use of index lines and damage assessments to estimate population densities of snowshoe hares
Authors: Sullivan Thomas P. , Sullivan Druscilla S.
Published: January 2010

This study reports on the use of index lines to estimate the abundance of snowshoe hares in lodgepole pine stands in central British Columbia, Canada. Density estimates and related demographic information from the index lines were compared with a standard set of lines superimposed on a 9-ha grid. During the summer of a peak year in abundance, index line trapping provided reasonably accurate estimates of hare densities on a grid system. There was little variation in the demographic variables of reproduction, body weight, and sex ratio between line- and grid-sampled populations. Hare abundance and barking damage (feeding injuries to trees) were greater in heavily stocked stands of lodgepole pine than in lightly stocked stands. Index lines provide a rapid and economical survey method for censusing snowshoe hares in lodgepole pine stands.
Laminiscus n.g. (Monogenea: Gyrodactylidae) from capelin, Mallotus villosus (Müller), (Pisces: Osmeridae) in the northwest Atlantic with redescriptions of L. gussevi n. comb., Gyrodactyloides petruschewskii, and G. andriaschewi
Authors: Pálsson Jónbjörn , Beverley-Burton Mary
Published: January 2010

Three species of viviparous monogenea, Gyrodactyloides petruschewskii Bykhovskii, 1947, G. andriaschewi Bykhovskii and Polyanskii, 1953, and Laminiscus gussevi (Bykhovskii and Polyanskii, 1953) n. comb., from the gills of capelin, Mallotus villosus (Müller), taken in the northwest Atlantic and Icelandic waters are redescribed in order to provide a better understanding of the functional morphology of the haptor. Laminiscus n.g. is proposed with L. gussevi n. comb., which is transferred from Gyrodactyloides, as type-species. Laminiscus is distinguished by having a sclerotized plate which supports the haptor and in lacking the ventral suction disc and associated sclerites which characterize Gyrodactyloides. Two other species, which do not parasitize capelin, are included in Laminiscus: L. strelkowi (Bykhovskii and Polyanskii, 1953) n. comb., and L. dogiele (Zhukov, 1960) n. comb. An emended generic diagnosis for Gyrodactyloides is included. All three specific reports are new geographic records.
Influence of season, gonadotropins, and gonadal hormones on the thyroid activity of freshwater perch, Anabas testudineus (Bloch)
Authors: Chakraborti Pradip , Rakshit Deb Kumar , Bhattacharya Samir
Published: January 2010

Perch thyroid activity fluctuated in different phases of the reproductive cycle, being highest at spawning and lowest at postspawning. Treatment of intact perch with salmon gonadotropin (SG-G100) or ovine luteinizing hormone (LH) (1 μg/100 g body weight) for 15 days markedly enhanced thyroid activity. The extent of stimulation was greater with SG-G 100 than with LH. Follicle-stimulating hormone (FSH) had no effect. Ovarian steroids, 17β-estradiol and estrone (100 ng/100 g body weight), also significantly augmented thyroid activity. There was a striking reduction of thyroid activity as a result of ovariectomy, a decrease that could not be improved by SG-G100; however, estrone or 17β-estradiol supplementation resulted in a significant increase of thyroid activity in comparison with ovariectomized controls. These findings suggest that gonadotropin mediated its stimulatory effect on perch thyroid activity via the release of ovarian steroids.
Description of Sarcocystis campestris sp. n. (Protozoa: Sarcocystidae): a parasite of the badger Taxidea taxus with experimental transmission to the Richardson's ground squirrel, Spermophilus richardsonii
Authors: Cawthorn Richard J. , Wobeser Gary A. , Gajadhar Alvin A.
Published: January 2010

Sarcocystis campestris sp. n. (Protozoa: Sarcocystidae) is an heteroxenous coccidium with badgers (Taxidea taxus) as natural and experimental definitive hosts and Richardson's ground squirrels (Spermophilus richardsonii) as experimental intermediate hosts. Free sporocysts (10.2 × 8.0 μm with a large, round sporocyst residuum consisting of a single refractile granule), obtained from intestinal scrapings of badgers (carcasses frozen 2 years at −20 °C), were orally administered to juvenile Richardson's ground squirrels. Acute fatal sarcocystosis developed in some squirrels at 11–13 days postinoculation (p.i.). Meronts (second generation) were present 9–12 days p.i. in the vascular endothelium of many tissues (especially the lungs). Cysts developed in skeletal muscle, contained metrocytes (7 × 5 μm) 30 days p.i., and beginning 46 days p.i., bradyzoites (12.0 × 3.5 μm) were present. Cysts were macroscopic as early as 258 days p.i. Squirrel carcasses containing cysts (76 days p.i.) of S. campestris sp. n. were fed to Sarcocystis-free badgers. The prepatent period was 9 days and the patent period at least 13 days. Both badgers were ill early in the patent period and passed unformed feces during the patent period. Free sporocysts were 10.2 × 8.0 μm and each had an elongate sporocyst residuum containing numerous small refractile granules.
Influence of sampling on the interpretation of haematological measurements of rainbow trout, Salmo gairdneri
Authors: Lowe-Jinde L. , Niimi A. J.
Published: January 2010

Haematological parameters of rainbow trout (Salmo gairdneri) were examined to determine if the sampling influenced the measurements. The results indicated that haematocrit values of fish anesthetized with tricaine methanesulfonate (TMS or MS 222) sampled after 5–20 min were significantly higher than of fish sampled within 1 min of capture and anesthesia. No differences were observed among haemoglobin content, erythrocyte, and leucocyte counts or their differential cell ratios over the 20-min period. Haemoglobin content and erythrocyte counts increased significantly with size among the three groups examined. It is suggested that differential blood cell ratios could be used as a reliable haematological index because the ratios appear to be independent of the effects of sampling over a short time period.
Seasonal changes in activity patterns and the adaptive value of haying in pikas (Ochotona princeps)
Authors: Conner Douglas A.
Published: January 2010

Seasonal changes in the performance of four behaviors, perching, haying, feeding, and surface activity were studied in two populations of North American pikas (Ochotona princeps) living in Colorado. During late summer and early fall (July–September), haying, the gathering of meadow vegetation followed by storing it in their talus territories, made up almost 55% of the pikas' surface activity. After haying ceased, pikas continued to feed in the meadows until snowpack, cold temperatures, and the absence of surface vegetation made this impossible. Beginning in February, individuals remained under the snowpack feeding on vegetation from their hay piles and on lichens available below the snow. Surface activity was not seen again until May when spring vegetation began to appear. Haying appears to be an adaptive response to environmental unpredictability. Hay piles most likely become critical for survival when harsh weather prevents surface foraging and(or) delays the emergence of new vegetation growth in the spring or early summer. It is suggested that the evolution of territoriality in pikas is related to the need to gather sufficient vegetation to serve as a potential winter food supply during years when the winter season is unusually harsh or prolonged.
Limites et améliorations du sexage des salmonidés par dosage de la 11-cétotestostérone circulante
Authors: Bail P.-Y. Le , Fostier A. , Marcuzzi O.
Published: January 2010

The use of plasma concentrations of 11-ketotestosterone for determining sex has been studied in various species of salmonids (O. kisutch, S. salar, S. gairdneri, S. trutta) at different stages of their sexual development. Radioimmunological titrations were performed; though they are less sensitive than filtrations with an extraction by organic solvents, they are quicker to use. The percentage of error in sex determination is low (5%) in animals that have developing gonads or that are still in prepuberty, but is much higher in immature animals. A single injection of total pituitary extract (equivalent to 100 ng of s-GtH per gram) will reduce this error to 2% by stimulating 11-ketotestosterone secretion.[Journal translation]
The effect of pH on tricaine methanesulfonate induced anaesthesia of the newt Notophthalmus viridescens
Authors: Robinson Mary E. , Scadding Steven R.
Published: January 2010

The anaesthetic tricaine methanesulfonate (TMS), when dissolved in distilled water, yields an acidic solution. To determine if pH affected the anaesthetic efficacy of TMS in the newt Notophthalmus viridescens, newts were anaesthetized in 0.1% TMS solutions adjusted to pH's of 3, 4, 5, 6, 7, or 8 with NaOH. As the pH increased, there was a significant decrease in the time required to induce anaesthesia and an increase in the time required to recover from the anaesthetic. We conclude that adjusting the pH of TMS solutions towards neutrality increases their anaesthetic efficacy.
Incubation weight loss in the mallard
Authors: Gatti Ronald C.
Published: January 2010

Incubating mallard (Anas platyrhynchos) hens were trapped on their nests in southern Manitoba during 1975–1977 to document weight trends. In 1975, hens lost an average of 7.4 g per day incubating, 18% of the calculated initial body weight. Weight lost during incubation was greatest (27%) for early nesting hens and lowest in late nesting hens (11%). Weight loss patterns were less clear but changes were lower in magnitude in 1976. Possible explanations relating to weather and local population changes are discussed. Recapture weights of individual hens support the relationship between incubation weight loss and nesting chronology.
Dispersal and site fidelity in Blue Grouse
Authors: Jamieson Ian G. , Zwickel Fred C.
Published: January 2010

Ten years of banding and censusing data from Blue Grouse (Dendragapus obscurus) were analyzed with respect to dispersal of juveniles and site fidelity of yearlings and adults. Juvenile females dispersed farther than juvenile males. In sibling pairs of the same sex, brothers settled closer to one another than sisters. In sibling pairs with birds of opposite sex, females dispersed farther than males. Adult males first established territories close to where they had been sighted as yearlings, or nonterritorial adults, and most females returned in spring to the same general area where they had previously nested. Two-year-old females showed less fidelity to breeding sites they had used as yearlings than older females to sites they had used in previous years.
Les parasites de l'éperlan d'amérique (Osmerus mordax) anadrome du Québec et leur utilité comme étiquettes biologiques
Authors: Fréchet A. , Dodson J. J. , Powles H.
Published: January 2010

Distribution of smelt parasites Glugea hertwigi, Diphyllobothrium sebago, and Echinorhynchus salmonis support previous hypotheses that three groups of anadromous smelt occur in Quebec waters. These groups are associated with three geographical areas: the Saguenay fjord, the south shore of the St. Lawrence estuary, and Chaleur Bay. Furthermore, the presence of two parasites almost exclusive to the smelt sampled in Forestville and Baie Comeau confirms the existence of a fourth group.
Tau as an index of similarity in community comparisons: an approach permitting the hypothesis of unequal species abundance
Authors: Ghent A. W.
Published: January 2010

P. A. Jumars (Ecology, 61: 1553–1554. 1980) has argued that in significance tests of τ where it is employed in community comparisons, the null hypothesis that all rankings of species are equally likely can be translated only into the hypothesis that all species are equally abundant. An alternative translation is presented, in which it is the species names that are equally likely to be attached to unequal partitionings of the population. Some biological justifications for this alternative model are offered. It is shown that Jumars' example calculations illustrate type II rather than type I statistical errors, so that the "serious doubt" that he expresses about published community comparison significance tests applies to acceptances rather than rejections of the null. The alternative index of community similarity he proposes, based upon contingency table analyses of species counts, is shown to reflect excessive sampling homogeneity rather than community similarity.
Metabolic reserves and enzyme activities with food deprivation in immature American eels, Anguilla rostrata (LeSueur)
Authors: Moon Thomas W.
Published: January 2010

Changes in tissue metabolic reserves and enzyme activities have been evaluated after food depriving immature American eels (Anguilla rostrata) for 6 months. Tissue carbohydrate status was maintained, but significant depletion of insoluble myofibrillar protein occurred. Plasma free fatty acids increased and muscle lipids generally increased; the source of these additional fats is not known. Activities of glycolytic, gluconeogenic, and amino acid metabolizing enzymes were generally conserved in liver and red and white muscles, consistent with a lack of change in soluble tissue protein. The few exceptions were decreases in muscle phosphorylase and white muscle fructose-1,6-bis-phosphatase. Activities of gluconeogenic enzymes were found in red muscle, but the significance of this result could not be evaluated. The pattern of branched-chain amino acid metabolizing enzymes is quite distinct from that reported for mammalian tissues, implying an altered whole body turnover of these amino acids in the eel (and probably other fish as well). These data are discussed in relation to other fish studies, emphasizing the role of protein amino acids in the fasting strategy of the immature eel and the importance of the prior dietary history of the fish to the observed results.
Life history variations in two populations of Sphaerium rhomboideum (Bivalvia: Pisidiidae)
Authors: Mackie G. L. , Flippance L. A.
Published: January 2010

Distinctly different life history patterns of Sphaerium rhomboideum were observed in two permanent ponds within 1 km of each other near Guelph, Ontario. Compared with the population from the large pond, the population from the small pond usually had larger numbers of newborn (40% vs. 20%) that did not grow immediately after birth, three birth periods (peaks in late May, July to August, and October to November) instead of one (peak in September), significantly smaller newborn (3.8–4.2 mm in length depending on birth period vs. 4.5 mm in length), significantly faster average summer growth rates (0.147 mm∙day−1 vs. 0.062 mm∙day−1), shorter longevities (12 months vs. 14 months), both semelparous and iteroparous reproduction (depending on birth period) as opposed to only iteroparous reproduction in the other population, and less mortality of larvae (58% vs. 72%) resulting in annual ratios of selection of 3.21 for the semelparous form and 4.39 for the iteroparous form as opposed to 5.08 for the iteroparous form in the other population. Neither r, K, nor stochastic theories of life history tactics appear to predict the differences in life history patterns of these two populations of S. rhomboideum.