bluuebunny/crossref_metadata_2025 huggingface dataset:
Validation of a CFD Model for Coupled Simulation of Nozzle Flow, Primary Fuel Jet Break-Up and Spray Formation
Authors: v. Berg E. , Edelbauer W. , Tatschl R. , Volmajer M. , Kegl B. , Alajbegovic A. , Ganippa L.
Published: February 2009

A coupled simulation methodology for cavitating nozzle flow and spray formation has been developed at AVL and applied within the framework of the FIRE CFD code. In this approach a two-fluid model for cavitating nozzle flow inside the injector and a primary break-up model applied at the nozzle orifice are combined with the standard Discrete Droplet Model (DDM). Using an alternative calculation method presently also an approach with an Eulerian multi-fluid model applied for the nozzle and spray regions together is developed. A two-fluid model is used to simulate injector flows. The primary break-up model developed is based on locally resolved properties of the cavitating nozzle flow in the orifice cross section. The model delivers the initial droplet size and velocity distribution with droplet parcels released from the surface of a coherent liquid core. The characteristic feature of the results from the model is a remarkable asymmetry of the spray. Recent experimental findings from Chalmers University gained from a transparent model injector are used for model validation.
Evaluation of Turbulence Models for the Prediction of Wind Turbine Aerodynamics
Authors: Benjanirat Sarun , Sankar Lakshmi N. , Xu Guanpeng
Published: February 2009

The performance of the NREL Phase VI horizontal axis wind turbine has been studied with a 3-D unsteady Navier-Stokes solver. This solver is third order accurate in space and second order accurate in time, and uses an implicit time marching scheme. Calculations were done for a range of wind conditions from 7 m/s to 25 m/s where the flow conditions ranged from attached flow to massively separated flow. A variety of turbulence models were studied: Baldwin-Lomax Model, Spalart-Allmaras one-equation model, and k-ε two equations model with and without wall corrections. It was found all the models predicted the normal forces and associated bending moments well, but most of them had difficulties in modeling the chord wise forces, power generation, and pitching moments. It was found that the k-ε model with near wall corrections did the best job of predicting most the quantities with acceptable levels of accuracy. Additional studies aimed at transition model development, and grid sensitivity studies in the tip region are deemed necessary to improve the correlation with experiments.
Optimization of Wind Turbines Using Helicoidal Vortex Model
Authors: Chattot Jean-Jacques
Published: February 2009

The problem of the design of a wind turbine for maximum output is addressed from an aerodynamical point of view. It is shown that the optimum inviscid design, based on the Goldstein model, satifies the minimum energy condition of Betz only for light loading. The more general equation governing the optimum is derived and an integral relation is obtained, stating that the optimum solution satisfies the minimum energy condition of Betz in the Trefftz plane “in the average”. The discretization of the problem is detailed, including the viscous correction based on the 2-D viscous profile data. A constraint is added to account for the force on the tower. The minimization problem is solved very efficiently by relaxation. Several optimized solutions are calculated and compared with the NREL rotor, using the same profile, but different chord and twist distributions. In all cases, the optimization produces a more efficient design.
Alternative Composite Materials for Megawatt-Scale Wind Turbine Blades: Design Considerations and Recommended Testing
Authors: Griffin Dayton A. , Ashwill Thomas D.
Published: February 2009

As part of the U.S. Department of Energy’s Wind Partnerships for Advanced Component Technologies program, Global Energy Concepts LLC (GEC) is performing a study concerning blades for wind turbines in the multi-megawatt range. Earlier in this project constraints were identified to cost-effective scaling-up of the current commercial blade designs and manufacturing methods, and candidate innovations in composite materials, manufacturing processes and structural configurations were assessed. In the present work, preliminary structural designs are developed for hybrid carbon fiber/fiberglass blades at system ratings of 3.0 and 5.0 megawatts. Structural performance is evaluated for various arrangements of the carbon blade spar. Critical performance aspects of the carbon material and blade structure are discussed. To address the technical uncertainties identified, recommendations are made for new testing of composite coupons and blade sub-structure.
Using Environmental Contours to Predict Extreme Events on Wind Turbines
Authors: Fitzwater LeRoy M. , Cornell C. Allin , Veers Paul S.
Published: February 2009

This paper presents and explores estimating design loads on wind turbines using the environmental contour method. Contours promise to provide both practical reliability estimation and valuable information about the combination of joint environmental variable values, e.g. wind speed and turbulence, most critical to each specific wind turbine. We present the background of the development of environmental contours as applied to wind energy systems, and apply this theory, in three examples, to develop contours based either (1) on design code description of environmental conditions, or (2) on measured data for a site-specific application. The site-specific case is used for both stall and pitch controlled turbine examples. From these contours, and a functional description of the short-term response of the turbine, implicit FORM estimates are made for the turbine response; these estimates are compared with results obtained from numerical integration of the short-term response of the turbine over the joint distribution of wind speed and turbulence. We find that the environmental contour method provides reasonable estimates of the expected extreme load, compared with the full integration method.
Wick calculus using the technique of integration within an ordered product of operators
Authors: Fan Hong-yi , Lü Cui-hong
Published: February 2009

We show that the connection between Wick ordered polynomials and Hermite polynomials derived by Wurm and Berg by an inductive method can be directly and concisely obtained using the technique of integration within an ordered product of operators (IWOP).
Generation of Bessel beams using a 4-f spatial filtering system
Authors: Kowalczyk Jeremy M. D. , Smith Stefanie N. , Szarmes Eric B.
Published: February 2009

We demonstrate a simple and straightforward method of producing Bessel beams using a 4-f spatial filtering system that requires no specialized optical components. The experiment employs the established technique of diffraction from a thin ring source, but the ring source is produced by the high-pass filtering of a uniformly illuminated circular aperture, yielding Bessel beams with a central spot radius of less than 35μm which persist over a distance of 160mm. The experiment unifies diffraction theory, Fourier optics, and the properties of Bessel beams in a manner appropriate for an advanced undergraduate laboratory.
Promoting instructional change via co-teaching
Authors: Henderson Charles , Beach Andrea , Famiano Michael
Published: February 2009

Physics Education Research (PER) has made significant progress in developing effective instructional strategies, but disseminating the background knowledge and strategies to other faculty has proven difficult. Co-teaching is a promising and cost-effective alternative to traditional professional development which may be applicable in particular situations. We discuss the theoretical background of co-teaching and describe our initial experience with it. A new instructor (Famiano) co-taught an introductory calculus-based physics course with an instructor experienced in PER-based reforms (Henderson). The pair taught within the course structure typically used by Henderson and met regularly to discuss instructional decisions. An outsider (Beach) conducted separate interviews with each instructor and observed several class sessions. Classroom observations show an immediate use of PER-based instructional practices by the new instructor. Interviews show a significant shift in the new instructor’s beliefs about teaching and intentions of future use of PER-based instructional approaches.
Work and energy in inertial and noninertial reference frames
Authors: Diaz Rodolfo A. , Herrera William J. , Manjarrés Diego A.
Published: February 2009

It is usual in introductory courses of mechanics to develop the work and energy formalism from Newton’s laws. It has been shown how forces transform under a change of reference frame. No analogous study is usually done for the way in which work and energy transform under a change of reference frames. We analyze the behavior of energy and work under such transformations and explicitly show the expected invariance of the formalism under Galilean transformations for one particle and a system of particles. The case of noninertial systems is also analyzed and the fictitious work is characterized. In particular, we showed that the total fictitious work in the center of mass system vanishes even if the center of mass defines a noninertial frame. Some subtleties that arise from the formalism are illustrated by examples.
Resistance of a square lamina by the method of images
Authors: Mead Lawrence R.
Published: February 2009

The method of images is applied to find the net resistance of a square lamina whose input/output currents are through point contacts at opposite corners. This application illustrates the rare use of the method of images with an infinite number of image charges.
The Orphan G Protein–Coupled Receptor 3 Modulates Amyloid-Beta Peptide Generation in Neurons
Authors: Thathiah Amantha , Spittaels Kurt , Hoffmann Marcel , Staes Mik , Cohen Adrian , Horré Katrién , Vanbrabant Mieke , Coun Frea , Baekelandt Veerle , Delacourte André , Fischer David F. , Pollet Dirk , De Strooper Bart , Merchiers Pascal
Published: February 2009

Deposition of the amyloid-β peptide is a pathological hallmark of Alzheimer's disease. A high-throughput functional genomics screen identified G protein–coupled receptor 3 (GPR3), a constitutively active orphan G protein–coupled receptor, as a modulator of amyloid-β production. Overexpression of GPR3 stimulated amyloid-β production, whereas genetic ablation of GPR3 prevented accumulation of the amyloid-β peptide in vitro and in an Alzheimer's disease mouse model. GPR3 expression led to increased formation and cell-surface localization of the mature γ-secretase complex in the absence of an effect on Notch processing. GPR3 is highly expressed in areas of the normal human brain implicated in Alzheimer's disease and is elevated in the sporadic Alzheimer's disease brain. Thus, GPR3 represents a potential therapeutic target for the treatment of Alzheimer's disease.
Lunar Global Shape and Polar Topography Derived from Kaguya-LALT Laser Altimetry
Authors: Araki H. , Tazawa S. , Noda H. , Ishihara Y. , Goossens S. , Sasaki S. , Kawano N. , Kamiya I. , Otake H. , Oberst J. , Shum C.
Published: February 2009

A global lunar topographic map with a spatial resolution of finer than 0.5 degree has been derived using data from the laser altimeter (LALT) on board the Japanese lunar explorer Selenological and Engineering Explorer (SELENE or Kaguya). In comparison with the previous Unified Lunar Control Network (ULCN 2005) model, the new map reveals unbiased lunar topography for scales finer than a few hundred kilometers. Spherical harmonic analysis of global topographic data for the Moon, Earth, Mars, and Venus suggests that isostatic compensation is the prevailing lithospheric support mechanism at large scales. However, simple rigid support is suggested to dominate for the Moon, Venus, and Mars for smaller scales, which may indicate a drier lithosphere than on Earth, especially for the Moon and Venus.
A Neural Mechanism for Microsaccade Generation in the Primate Superior Colliculus
Authors: Hafed Ziad M. , Goffart Laurent , Krauzlis Richard J.
Published: February 2009

During fixation, the eyes are not still but often exhibit microsaccadic movements. The function of microsaccades is controversial, largely because the neural mechanisms responsible for their generation are unknown. Here, we show that the superior colliculus (SC), a retinotopically organized structure involved in voluntary-saccade target selection, plays a causal role in microsaccade generation. Neurons in the foveal portion of the SC increase their activity before and during microsaccades with sizes of only a few minutes of arc and exhibit selectivity for the direction and amplitude of these movements. Reversible inactivation of these neurons significantly reduces microsaccade rate without otherwise compromising fixation. These results, coupled with computational modeling of SC activity, demonstrate that microsaccades are controlled by the SC and explain the link between microsaccades and visual attention.
Polydnaviruses of Braconid Wasps Derive from an Ancestral Nudivirus
Authors: Bézier Annie , Annaheim Marc , Herbinière Juline , Wetterwald Christoph , Gyapay Gabor , Bernard-Samain Sylvie , Wincker Patrick , Roditi Isabel , Heller Manfred , Belghazi Maya , Pfister-Wilhem Rita , Periquet Georges , Dupuy Catherine , Huguet Elisabeth , Volkoff Anne-Nathalie , Lanzrein Beatrice , Drezen Jean-Michel
Published: February 2009

Many species of parasitoid wasps inject polydnavirus particles in order to manipulate host defenses and development. Because the DNA packaged in these particles encodes almost no viral structural proteins, their relation to viruses has been debated. Characterization of complementary DNAs derived from braconid wasp ovaries identified genes encoding subunits of a viral RNA polymerase and structural components of polydnavirus particles related most closely to those of nudiviruses—a sister group of baculoviruses. The conservation of this viral machinery in different braconid wasp lineages sharing polydnaviruses suggests that parasitoid wasps incorporated a nudivirus-related genome into their own genetic material. We found that the nudiviral genes themselves are no longer packaged but are actively transcribed and produce particles used to deliver genes essential for successful parasitism in lepidopteran hosts.
Farside Gravity Field of the Moon from Four-Way Doppler Measurements of SELENE (Kaguya)
Authors: Namiki Noriyuki , Iwata Takahiro , Matsumoto Koji , Hanada Hideo , Noda Hirotomo , Goossens Sander , Ogawa Mina , Kawano Nobuyuki , Asari Kazuyoshi , Tsuruta Sei-itsu , Ishihara Yoshiaki , Liu Qinghui , Kikuchi Fuyuhiko , Ishikawa Toshiaki , Sasaki Sho , Aoshima Chiaki , Kurosawa Kosuke , Sugita Seiji , Takano Tadashi
Published: February 2009

The farside gravity field of the Moon is improved from the tracking data of the Selenological and Engineering Explorer (SELENE) via a relay subsatellite. The new gravity field model reveals that the farside has negative anomaly rings unlike positive anomalies on the nearside. Several basins have large central gravity highs, likely due to super-isostatic, dynamic uplift of the mantle. Other basins with highs are associated with mare fill, implying basalt eruption facilitated by developed faults. Basin topography and mantle uplift on the farside are supported by a rigid lithosphere, whereas basins on the nearside deformed substantially with eruption. Variable styles of compensation on the near- and farsides suggest that reheating and weakening of the lithosphere on the nearside was more extensive than previously considered.
Subaqueous eruption and shallow-water reworking of a small-volume Surtseyan edifice at Kakanui, New Zealand
Authors: Corcoran P. L. , Moore L. N.
Published: February 2009

Kakanui volcaniclastic deposits on the South Island of New Zealand are the remnants of two late Eocene to early Oligocene Surtseyan-type cones. Eruptive-dominated material of the (i) stratified tuff and lapilli tuff, and (ii) lapilli tuff breccia lithofacies and post-eruptive debris of the (iii) shell-rich tuff and lapilli tuff, and (iv) chaotic and cross-bedded tuff and lapilli tuff lithofacies compose the deposits. The 9–250 m thick stratified tuff and lapilli tuff contains grain-flow deposits originating from low-volume tephra jets and local thinning and fining upward sequences that formed from density currents during sustained uprush. The lapilli tuff breccia, up to 4.5 m thick, contains inward-dipping beds deposited via debris flows along inner-cone walls. Burrows and articulated shells in the 2–4 m thick shell-rich tuff and lapilli tuff indicate volcanic quiescence and low sedimentation rates, whereas shell fragments upsection signal increased wave and current activity. Burrows, pyrite concretions, and mudstone in the lower part of the 26 m thick chaotic tuff and lapilli tuff indicate suspension deposition and cessation in pyroclastic volcanism. High-angle trough cross-beds and limestone rip-up fragments upsection are consistent with wave-induced current reworking. The depositional model involves a Surtseyan-type eruption on a continental shelf, followed by colonization of organisms on the tops of planed-off cones. The Kakanui deposits comprise a cluster of cones constituting part of a late Eocene – early Oligocene monogenetic volcanic field. The Kakanui succession provides an opportunity to study deposits that form from explosive subaqueous pyroclastic eruptions and wave-dominated deposition and erosion.
Regional characterization of the Paskapoo bedrock aquifer system, southern AlbertaGeological Survey of Canada Contribution 2008-0479.
Authors: Grasby Stephen E. , Chen Zhuoheng , Hamblin Anthony P. , Wozniak Paul R.J. , Sweet Arthur R.
Published: February 2009

The Paskapoo Formation of southern Alberta supports more groundwater wells than any other aquifer system in the Canadian Prairies. Located in a region of rapid population growth and straddling watersheds where no new surface water licenses are available, this aquifer system is under increasing pressure to provide water supply. The Paskapoo Formation represents a foreland deposit of a siltstone- and mudstone-dominated fluvial system. The system is highly heterogeneous with broad ranges in physical properties that impact groundwater production. High-porosity coarse-grained channel sandstone can provide productive wells, whereas thin and fractured sands and siltstones are low producers. The basal Haynes Member and western portion of the Paskpaoo Formation have higher sandstone volumes than other portions of the system. Fracture density shows a strong inverse relationship to bed thickness, such that fracture flow becomes more important for thinner sandstone beds. There is no regional-scale flow system associated with the Paskapoo Formation; rather it is dominated by local-scale recharge processes. The geochemistry of Paskapoo Formation groundwater is largely controlled by the variable composition of immediately overlying glacial deposits.
The relative weight of traditions, economics, and catch plans in New Zealand fleet dynamics
Authors: Marchal Paul , Lallemand Philippe , Stokes Kevin
Published: February 2009

We investigate the relative weights of catch plans, expected profit, and traditions in fishers’ decision-making for five New Zealand fleets subject to an individual transferable quota (ITQ) management regime. Métiers were defined for these fleets as a combination of gears, management units, and a targeting index (either target species or statistical area). A nested logit random utility model was used to model the métier allocation of fishing effort in relation to catch plans, expected profit, and past fishing allocations. This study showed that traditions and catch plans appeared to be important determinants of fishers’ behavior for these New Zealand fleets. The model developed in this study fitted the data generally well and was also able to predict, in most cases, future effort allocation both one month and one year ahead.
Estimating establishment probabilities of Cladocera introduced at low density: an evaluation of the proposed ballast water discharge standards
Authors: Bailey Sarah A. , Vélez-Espino Luis Antonio , Johannsson Ora E. , Koops Marten A. , Wiley Chris J.
Published: February 2009

The International Maritime Organization has proposed ballast water discharge standards to reduce densities of taxa transported in ballast water. While reduced propagule pressure will almost certainly lower the risk of species introductions, we ask if the proposed standards will be effective against taxa capable of rapid population growth from small inocula, such as parthenogenetic taxa. We modified a diffusion approximation to calculate establishment probabilities as the probability of reaching a critical threshold density necessary to initiate sexual reproduction (and production of diapausing eggs for long-term persistence) before the onset of adverse environmental conditions. We parameterize our model for six Cladocera using growth rates measured during enclosure experiments conducted under favourable environmental conditions (i.e., using a precautionary approach). We then examine predicted establishment probabilities at different inoculum densities to determine the efficacy of the proposed ballast water discharge standards. Our results indicate that future technologies in compliance with the proposed standards could reduce establishment probabilities for some parthenogenetic zooplankton threefold; however, there is still a risk of establishment for some taxa.
Factors influencing the achievement of steady state in mercury contamination among lakes and catchments of south-central Ontario
Authors: Mills R. Brad , Paterson Andrew M. , Blais Jules M. , Lean David R.S. , Smol John P. , Mierle Greg
Published: February 2009

Mercury (Hg) concentrations in recent (0.5–1 cm) and preindustrial (>30 cm) sediments were examined across lakes in south-central and eastern Ontario, Canada (45.53°N, 82.41°W to 44.15°N, 76.25°W), to determine whether Hg exported from watersheds is at steady state with atmospheric deposition. An examination of headwater lakes revealed that Hg enrichment was not uniform among watersheds but that the enrichment factor (EF = [Hg]present day/[Hg]preindustrial, standardized for organic matter) decreased as a function of drainage ratio (Ad /Ao, watershedarea/lakearea). Furthermore, the model fit was improved after accounting for differences in sulfate concentrations and pH among lakes: EF = (Ad /Ao)–15.96 – 0.07(SO 42– ) – (3.55(pH>8.3)) (R2 = 0.458, p = 0.0001). Hg concentrations in preindustrial sediments of headwater lakes showed a positive linear relationship with drainage ratio (partial t = 4.83, p < 0.0001, n = 66) that was strengthened following an adjustment for mean annual runoff (MAR) ([Hg]preindustrial = 0.011 ± 0.002(Ad /Ao) + 0.0008 ± 0.0003(MAR) (R2 = 0.108, F[1,66] = 8.01, p = 0.006)). Our results suggest that Hg export from watersheds may be currently lagging behind atmospheric Hg deposition, in which case, Hg export would increase into the future, even as Hg deposition from the atmosphere stabilizes.
Effects of sampling effort, assemblage similarity, and habitat heterogeneity on estimates of species richness and relative abundance of stream fishes
Authors: Fischer Jesse R. , Paukert Craig P.
Published: February 2009

We estimated the sampling effort required to accurately estimate species richness and to detect changes in catch-per-unit-effort (CPUE) in four Great Plains, USA, streams. The number of sampled reaches (i.e., <1 km) required to estimate stream-segment (i.e., 20–28 km) species richness decreased with increased sampled reach length (i.e., 10, 20, 40, or 60 mean stream widths, MSW), whereas total sampling effort decreased with a greater number of shorter sampled reaches. Collecting all species in a stream segment required all sampled reaches (i.e., 10) of a length equal to 40 or 60 MSW. The number of stream reaches sampled with lengths equal to 40 MSW required to detect a 50% change in CPUE of common species (i.e., total abundance > 1% of total catch) with β = 0.80 ranged from 7 to 630 (mean = 99) and decreased with longer sampled reaches. A greater number of sampled reaches were needed to detect 90% of species richness and 25% changes in CPUE when Jaccard’s similarity of samples of stream fish assemblages and habitat heterogeneity was lower within streams. Our results suggest that homogeneous stream segments require more sampled reaches to characterize fish assemblages and monitor trends in fish abundance.
Biogenic calcite–phosphorus precipitation as a negative feedback to lake eutrophication
Authors: Hamilton Stephen K. , Bruesewitz Denise A. , Horst Geoffrey P. , Weed David B. , Sarnelle Orlando
Published: February 2009

Lakes in carbonate-rich watersheds commonly precipitate calcium carbonate as calcite, and this is accelerated by photosynthetic uptake of carbon dioxide. Co-precipitation of phosphate with calcite is one reason that algal growth in such lakes tends to be strongly phosphorus (P) limited. The extent to which calcite precipitation can be a sink for added P, and thus act as a potential negative feedback to eutrophication, was demonstrated using large enclosures within a Michigan lake. Nitrogen and P were added over 45 days in the summer to produce mesotrophic and eutrophic conditions. Algal biomass and production increased markedly with the nutrient additions, elevating the pH (9–10) and greatly increasing calcite precipitation, reducing concentrations of calcium and alkalinity by up to 60%. Sediment traps indicated that calcite sedimentation was a major sink for added P. By the end of the experiment, only about half of the added P remained in the water column. Major ion concentrations in a larger set of Michigan lakes showed calcite precipitation to be widespread, reflecting the abundant carbonate minerals in this glacial region.
Characterization of dual-structure pore-size distribution of soil
Authors: Li X. , Zhang L. M.
Published: February 2009

The microporosity structure of soil provides important information in understanding the shear strength, compressibility, water-retention ability, and hydraulic conductivity of soils. It is a soil characteristic that depends on sample preparation method and wetting–drying history. A comprehensive study of the microporosity structure of a lean clay with sand was conducted in this research to investigate variations of the microporosity structure during compaction, saturation, and drying processes. Scanning electron microscopy was used to observe the microporosity structure of soil sample surfaces. Mercury intrusion porosimetry was used to measure the microporosity structure quantitatively by showing the relationship between cumulative pore volumes and pore radius. The experimental results show that a dual-porosity structure (i.e., interaggregate pores and intra-aggregate pores) forms during the compaction process. The interaggregate pores are compressible and the associated volume is closely related to the final void ratio of the compacted sample. Changes to interaggregate pores is dominant during compaction, but changes to intra-aggregate pores is dominant during saturation and drying. Based on the experimental results, a dual-porosity structure model was developed by relating the pore-size distribution to the void ratio. Consequently, the pore-size distribution at any void ratio can be predicted.
Miniature cone tip resistance of sand with fly ash using triaxial setup
Authors: Kumar Jyant , Raju K. V.S.B.
Published: February 2009

In a continuation of the authors’ recent work, the ultimate tip resistance of a miniature cone using triaxial equipment was determined for samples of dry sand mixed with dry fly ash. The effect of (i) the proportion of fly ash, (ii) the relative density of samples, and (iii) the vertical overburden pressure was examined. It was noted that an addition of fly ash in sand for the same range of relative density leads to a significant reduction in the ultimate tip resistance of the cone (qcu). This occurs due to a decrease in the friction angle (ϕ) of the sample with an increase in the fly ash content for a given relative density. For ϕ greater than about 30°, two widely used correlation curves from published literature, providing the relationships between qcuand ϕ for cohesionless soils, were found to provide satisfactory predictions, even for sand – fly ash mixtures. As was expected, the values of qcuincrease continuously with an increase in the relative density of the soil mass and the vertical effective (overburden) stress on the sample.
Long rockfall runout, Pascua Lama, Chile
Authors: Holm Kris , Jakob Matthias
Published: February 2009

Rockfall hazard assessments are a routine requirement for many engineers and geoscientists working in the field of geohazards. The scale of investigation and analysis is sometimes constrained by budget, and, in the simplest case, runout will be based on delineation of rockfall shadow zones. Some minimum rockfall shadow zones that have been reported in the literature are widely used by practitioners. We show that these values may not be conservative enough for a study area in the Chilean Andes. Our work suggests that smooth slopes devoid of vegetation may give rise to rockfall shadow zones several degrees below those commonly quoted in the literature. We hope that this short note alerts practitioners to calibrate site-specific rockfall shadow zones rather than relying on published values.
Reliability-based design of deep foundations based on differential settlement criterion
Authors: Roberts Lance A. , Misra Anil
Published: February 2009

Load–displacement analysis of a single deep foundation element can be accomplished by utilizing a soil–structure interaction model, such as the “t–z” model. By combining the soil–structure interaction model with a probabilistic analysis technique, such as Monte Carlo simulation, methods to rationally incorporate variability in the model parameters can be developed. As a result, the service limit state load capacity of a single deep foundation element can be computed for an allowable total head displacement. However, in design, differential settlement between individual foundation elements is often the event of interest. This paper develops a reliability-based design methodology for deep foundations based on a differential settlement design criterion. The design methodology is developed for various levels of uncertainty in the model parameters. The results are presented in the form of cumulative distribution functions that, combined with the calculated service limit state load capacity, form the basis for serviceability design of deep foundations based on a differential settlement criterion.
The Residual Stress in Thawing Soils
Authors: Nixon J. F. , Morgenstern N. R.
Published: February 2009

If a fine grained soil is thawed under undrained conditions, in general an effective stress exists in the soil skeleton. This effective stress is termed the residual stress. In ice-rich soil the residual stress may be zero, but various combinations of stress and thermal histories can result in significant residual stresses being generated upon thawing.A simple procedure for measuring the residual stress is described and the method is employed to obtain values for the residual stress in natural and reconstituted samples of frozen soil. The residual stress is found to be dependent on the void ratio in the thawed undrained condition. A profile of the residual stress with depth is given for the natural permafrost samples that have been tested.Some implications of the residual stress in practice are discussed, with particular emphasis on the undrained strength and deformation properties of thawed permafrost.
A Reexamination of the Geology of the Frank Slide
Authors: Cruden D. M. , Krahn J.
Published: February 2009

The landslide from the east face of Turtle Mountain that destroyed the southern end of the town of Frank in the Crowsnest Pass area of southwestern Alberta has become a classic example because it is one of the largest for which eye witness accounts and a contemporary scientific examination exist. Textbook accounts rely on the reports published shortly after the slide's occurrence in 1903.The slide was thought to have moved down the dip of a steeply inclined set of joints and has therefore been classified variously as a rockfall or block flow. Later regional and geological mapping has shown that the crest of Turtle Mountain lay close to the axis of the Turtle Mountain Anticline. A new detailed map shows that the slide mass lay on the steeply eastward dipping limb of the anticline and the crest of the fold lay very close to the crown of the slide. The slide probably took place on bedding surfaces with the orientation of the scarp and lateral margins of the slide controlled by joint sets. The surface of rupture close to the toe of the slide followed a minor thrust above the Turtle Mountain Fault. The slide is better classified as a rock slide.
A chromatography-free synthesis of (2S,12Z)-2-acetoxy-12-heptadecene — The major sex pheromone component of the pistachio twig borer moth (Kermania pistaciella)
Authors: Britton Robert , Khaskin Grigori , Gries Gerhard
Published: February 2009

Recently, (2S,12Z)-2-acetoxy-12-heptadecene was identified as the major sex pheromone component of the pistachio twig borer moth, Kermania pistaciella , one of the most serious insect pests of pistachio plantations in Iran and Turkey. In field studies, an attract-and-kill formulation containing (2S,12Z)-2-acetoxy-12-heptadecene demonstrated efficacy in reducing damage caused by K. pistaciella and may become a widely-used, earth-friendly tactic for control of this insect in commercial pistachio production. To further develop this technology, a cost-effective, chromatography-free synthesis of (2S,12Z)-2-acetoxy-12-heptadecene was required and is described in this communication.
Synthesis of arylbromides from arenes and N-bromosuccinimide (NBS) in acetonitrile — A convenient method for aromatic bromination
Authors: Zysman-Colman Eli , Arias Karla , Siegel Jay S.
Published: February 2009

Regioselective and chemoselective electrophilic bromination of a wide series of activated arenes using N-bromosuccinimide (NBS) in acetonitrile occurs readily. Environmentally friendly conditions, large substrate scope, and ease of synthesis enhance the utility of this method over other electrophilic bromination conditions.
ANALYSIS OF LONGITUDINAL MOMENTUM DISTRIBUTION OF 22Mg IN 12C(23Al, 22Mg)X REACTION
Authors: KUMAR RAVINDER , SINGH PARDEEP , KHARAB RAJESH , SHARMA H. C.
Published: February 2009

We have analyzed the longitudinal momentum distribution of 22 Mg fragment coming from 12 C (23 Al , 22 Mg ) X reaction at 74 MeV/A beam energy within the framework of Glauber model. The comparison of data and predictions has revealed that the valence proton in 23 Al occupies d-orbital and suppresses the expected proton halo because of the presence of a strong centrifugal barrier.
TSUNAMI EARLY WARNING SYSTEM — AN INDIAN OCEAN PERSPECTIVE
Authors: KUMAR B. PRASAD , KUMAR R. RAJESH , DUBE S. K. , RAO A. D. , MURTY TAD , GANGOPADHYAY AVIJIT , CHAUDHURI AYAN
Published: February 2009

On 26th December 2004, the countries within the vicinity of East Indian Ocean experienced the most devastating tsunami in recorded history. This tsunami was triggered by an earthquake of magnitude 9.0 on the Richter scale at 3.4°N, 95.7°E off the coast of Sumatra in the Indonesian Archipelago at 06:29 hrs IST (00:59 hrs GMT). One of the most basic information that any tsunami warning center should have at its disposal, is information on Tsunami Travel Times (TTT) to various coastal locations surrounding the Indian Ocean rim, as well as to several island locations. Devoid of this information, no ETA's (expected times of arrival) can be included in the real-time tsunami warnings. The work describes on development of a comprehensive TTT atlas providing ETA's to various coastal destinations in the Indian Ocean rim. This Atlas was first released on the first anniversary of the Indian Ocean Tsunami and was dedicated to the victims. Application of soft computing tools like Artificial Neural Network (ANN) for prediction of ETA can be immensely useful in a real-time mode. The major advantage of using ANN in a real-time tsunami travel time prediction is its high merit in producing ETA at a much faster time and also simultaneously preserving the consistency of prediction. Overall, it can be mentioned that modern technology can prevent or help in minimizing the loss of life and property provided we integrate all essential components in the warning system and put it to the best possible use.
Transcriptional Control of Mitochondrial Biogenesis and Function
Authors: Hock M. Benjamin , Kralli Anastasia
Published: February 2009

Mitochondria play central roles in energy homeostasis, metabolism, signaling, and apoptosis. Accordingly, the abundance, morphology, and functional properties of mitochondria are finely tuned to meet cell-specific energetic, metabolic, and signaling demands. This tuning is largely achieved at the level of transcriptional regulation. A highly interconnected network of transcription factors regulates a broad set of nuclear genes encoding mitochondrial proteins, including those that control replication and transcription of the mitochondrial genome. The same transcriptional network senses cues relaying cellular energy status, nutrient availability, and the physiological state of the organism and enables short- and long-term adaptive responses, resulting in adjustments to mitochondrial function and mitochondrial biogenesis. Mitochondrial dysfunction is associated with many human diseases. Characterization of the transcriptional mechanisms that regulate mitochondrial biogenesis and function can offer insights into possible therapeutic interventions aimed at modulating mitochondrial function.
Endocannabinoid Signaling and Long-Term Synaptic Plasticity
Authors: Heifets Boris D. , Castillo Pablo E.
Published: February 2009

Endocannabinoids (eCBs) are key activity-dependent signals regulating synaptic transmission throughout the central nervous system. Accordingly, eCBs are involved in neural functions ranging from feeding homeostasis to cognition. There is great interest in understanding how exogenous (e.g., cannabis) and endogenous cannabinoids affect behavior. Because behavioral adaptations are widely considered to rely on changes in synaptic strength, the prevalence of eCB-mediated long-term depression (eCB-LTD) at synapses throughout the brain merits close attention. The induction and expression of eCB-LTD, although remarkably similar at various synapses, are controlled by an array of regulatory influences that we are just beginning to uncover. This complexity endows eCB-LTD with important computational properties, such as coincidence detection and input specificity, critical for higher CNS functions like learning and memory. In this article, we review the major molecular and cellular mechanisms underlying eCB-LTD, as well as the potential physiological relevance of this widespread form of synaptic plasticity.
Immunobiology of Asthma
Authors: Hamid Qutayba , Tulic Meri
Published: February 2009

Asthma is characterized by chronic inflammation of the airways in which there is an overabundance of eosinophils, mast cells, and activated T helper lymphocytes. These inflammatory cells release mediators that then trigger bronchoconstriction, mucus secretion, and remodeling. The inflammatory mediators that drive this process include cytokines, chemokines, growth factors, lipid mediators, immunoglobulins, and histamine. The inflammation in allergic asthma can be difficult to control. This is mainly due to the development of an adaptive immunity to an allergen, leading to immunological memory. This leads to recall reactions to the allergen, causing persistent inflammation and damage to the airways. Generally, in asthma inflammation is directed by Th2 cytokines, which can act by positive feedback mechanisms to promote the production of more inflammatory mediators including other cytokines and chemokines. This review discusses the role of cytokines and chemokines in the immunobiology of asthma and attempts to relate their expression to morphological and functional abnormalities in the lungs of asthmatic subjects. We also discuss new concepts in asthma immunology, in particular the role of cytokines in airway remodeling and the interaction between cytokines and infection.
The effect of eating on lower esophageal sphincter electrical activity
Authors: Sanmiguel Claudia P. , Ito Yuichiro , Hagiike Masanobu , Conklin Jeffrey L. , Lalezari David , Soffer Edy E.
Published: February 2009

Electrical activity of the lower esophageal sphincter (LES) has been recorded mainly in vitro and in anesthetized animals. Swallowing produces relaxation of the LES, followed by its contraction. These changes should be associated with changes in LES electrical activity. To determine whether changes in LES electrical activity can be used to recognize the beginning of a meal, four dogs were implanted with two electrodes in the longitudinal axis of the LES. The electrodes were connected to an implantable device for recording of electrical activity. After recovery, dogs underwent two experiments: 1) combined recordings of LES electrical activity and esophageal manometry to test the effect of dry swallows, water, and solid food swallows on LES electrical activity and 2) telemetric recording of LES electrical activity during a standard meal. All amplitudes were in mV, means ± SD, ANOVA, P < 0.05. In experiment 1, an increase in the amplitude of LES electrical activity was associated with the substance being swallowed, i.e., at rest: 0.31 ± 0.06; dry swallows: 0.6 ± .0.1; water: 0.67 ± 0.12; solid food: 1.06 ± 0.17, P < 0.001. In experiment 2, there was a pronounced and characteristic increase in amplitude of LES electrical activity during feeding, 0.26 ± 0.1; during fasting, 0.99 ± 0.23; while eating, 0.31 ± 0.1 postprandial, P < 0.001. In conclusion, the beginning and duration of a meal are identified by distinct, easily recognizable changes in the amplitude of LES electrical activity. These changes depend on the type of the substance being swallowed and are most prominent with solid food. Changes in LES electrical activity can potentially be used for automatic eating detection.
Probiotic mixture VSL#3 protects the epithelial barrier by maintaining tight junction protein expression and preventing apoptosis in a murine model of colitis
Authors: Mennigen Rudolf , Nolte Kerstin , Rijcken Emile , Utech Markus , Loeffler Bettina , Senninger Norbert , Bruewer Matthias
Published: February 2009

Changes in epithelial tight junction protein expression and apoptosis increase epithelial permeability in inflammatory bowel diseases. The effect of the probiotic mixture VSL#3 on the epithelial barrier was studied in dextran sodium sulfate (DSS)-induced colitis in mice. Acute colitis was induced in BALB/c mice (3.5% DSS for 7 days). Mice were treated with either 15 mg VSL#3 or placebo via gastric tube once daily during induction of colitis. Inflammation was assessed by clinical and histological scores. Colonic permeability to Evans blue was measured in vivo. Tight junction protein expression and epithelial apoptotic ratio were studied by immunofluorescence and Western blot. VSL#3 treatment reduced inflammation (histological colitis scores: healthy control 0.94 ± 0.28, DSS + placebo 14.64 ± 2.55, DSS + VSL#3 8.43 ± 1.82; P = 0.011). A pronounced increase in epithelial permeability in acute colitis was completely prevented by VSL#3 therapy [healthy control 0.4 ± 0.07 (extinction/g), DSS + placebo 5.75 ± 1.67, DSS + VSL#3 0.26 ± 0.08; P = 0.003]. In acute colitis, decreased expression and redistribution of the tight junction proteins occludin, zonula occludens-1, and claudin-1, -3, -4, and -5 were observed, whereas VSL#3 therapy prevented these changes. VSL#3 completely prevented the increase of epithelial apoptotic ratio in acute colitis [healthy control 1.58 ± 0.01 (apoptotic cells/1,000 epithelial cells), DSS + placebo 13.33 ± 1.29, DSS + VSL#3 1.72 ± 0.1; P = 0.012]. Probiotic therapy protects the epithelial barrier in acute colitis by preventing 1) decreased tight junction protein expression and 2) increased apoptotic ratio.
High levels of caveolar cholesterol inhibit progesterone-induced genomic actions in human and guinea pig gallbladder muscle
Authors: Cong Ping , Pricolo Victor , Biancani Piero , Behar Jose
Published: February 2009

Gallbladder disease is prevalent during pregnancy. It has been suggested that this complication of pregnancy is attributable to increased bile cholesterol (Ch) induced by estrogens and to gallbladder hypomotility caused by increasing levels of progesterone (P4). Studies on nonpregnant gallbladders have shown that increased levels of bile Ch contribute to both gallstone formation and bile stasis. These studies investigated the effects of high levels of plasma membrane Ch on P4 on gallbladder muscle cells from human and guinea pigs. Contraction was studied in intact and permeabilized muscle cells. G proteins were determined by Western blot, and3H-P4 incorporation by muscle cells was measured in the β-scintillation counter. High levels of caveolar Ch blocked the effects induced by P4 treatment for 6 h. They suppressed the expected P4 inhibition of GTP-γS (a G protein activator)-induced contraction and changes in G proteins by downregulating Gi3 and upregulating Gs protein levels. Ch inhibited these P4 actions at the caveolar 3 (CAV-3) level, since the P4 effects were antagonized by treatment with CAV-3 antibody, by reducing CAV-3 expression through CAV-3 siRNA. CAV-3 antibody and siRNA reduced caveolar Ch levels. High caveolar levels of Ch and CAV-3 antibody blocked the incorporation of3H-P4 into caveolae. Treatment with GDP-βS (a G protein antagonist) had no effect on P4 actions. High caveolar Ch levels blocked the P4 effects on muscle contraction and G protein changes probably because both Ch and P4 require CAV-3 proteins for their transport across the plasma membrane.
Altered microvascular hemodynamics during the induction and perpetuation of chronic gut inflammation
Authors: Harris Norman R. , Whatley Joseph R. , Carter Patsy R. , Morgan Georgia A. , Grisham Matthew B.
Published: February 2009

Adoptive transfer of naïve CD4+T cells into lymphopenic mice induces chronic small and large bowel inflammation similar to Crohn's disease. Although much is now known regarding the immunopathology in this model of inflammatory bowel disease, virtually nothing is known about the microvascular hemodynamic changes during the induction and perpetuation of chronic gut inflammation. In this study, CD4+CD45RBhighT cells obtained from healthy C57BL/6 donor mice were transferred into lymphopenic recombinase-activating gene-1-deficient (RAG knockout) mice, which induced small and large bowel inflammation. At various time points following reconstitution (3 days-9 wk), intravital microscopy was used to examine the microvessels in the submucosa of the ileum and proximal colon following infusion of fluorescently labeled platelets and injection of rhodamine 6G (to label leukocytes). Hemodynamic measurements and the extent of blood cell adhesion to the venular wall were compared with measurements in unreconstituted RAG knockout controls. In <1 wk following reconstitution, velocity and wall shear rate of the arterioles decreased by >50% compared with controls, with this decrease also observed at 4–5 and 7–9 wk postreconstitution. At 7–9 wk, arteriolar diameters were found to be ∼15% larger than in controls, but, despite this dilation, flow rates in the individual vessels were decreased by ∼30%. Venular platelet and leukocyte adherence were not significantly elevated above controls; however, an association was found between platelet adherence and venular shear rate. In summary, significant decreases in arteriolar velocity and shear rates are observed in this model of chronic gut inflammation.