bluuebunny/crossref_metadata_2025 huggingface dataset:
A Simple Dynamical Model of the Warm-Water Branch of the Middepth Meridional Overturning Cell
Authors: Samelson R. M.
Published: November 2008

A reduced-gravity model is presented of the warm-water branch of the middepth meridional overturning circulation in a rectangular basin with a circumpolar connection. The model describes the balance between production of warm water by Ekman advection across the circumpolar current, dissipation of warm water by eddy fluxes southward across the current, and the net production or dissipation of warm water by diabatic processes north of the current. The results emphasize the role of the eastern boundary condition in setting the thermocline structure north of the current and the nonlinear interactions between wind forcing, eddy fluxes, and diabatic mixing, which together control the structure and amplitude of the model meridional overturning circulation. Solutions are shown to exist in which the northward Ekman transport across the circumpolar current is completely compensated by southward eddy fluxes and the meridional overturning north of the current is entirely driven by diabatic forcing and interior upwelling through the base of the layer. Other solutions are shown to exist in which the interior upwelling into the warm layer at midlatitudes is negligible and the meridional overturning circulation consists of a continuous cell that carried the fluid delivered by the northward Ekman transport across the circumpolar current through midlatitudes to the Northern Hemisphere subpolar gyre, where it cools and returns to depth. The results emphasize that the coupled elements of wind driving, eddy fluxes, and diabatic processes are inextricably intertwined in the middepth meridional overturning circulation.
ATSDR evaluation of potential for human exposure to benzene
Authors: Wilbur S , Wohlers D , Paikoff S , Keith LS , Faroon O
Published: November 2008

As part of its mandate, the Agency for Toxic Substances and Disease Registry (ATSDR) prepares toxicological profiles on hazardous chemicals found at Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA) National Priorities List (NPL) sites that have the greatest public health impact. These profiles comprehensively summarize toxicological and environmental information. This article constitutes the release of portions of the toxicological profile for benzene. The primary purpose of this article is to provide interested individuals with environmental information on benzene that includes production data, environmental fate, potential for human exposure, analytical methods, and a listing of regulations and advisories.
Thioglycolic acid inhibits mouse oocyte maturation and affects chromosomal arrangement and spindle configuration
Authors: Hou SY , Zhang L , Wu K , Xia L
Published: November 2008

Previous studies have shown that thioglycolic acid (TGA) leads to potential reproductive toxicology. To clarify the exact effects of this compound on reproduction, mice oocytes were treated with different TGA doses. At the end of the culture period, the nuclear status of mice oocytes was assessed under an inverted microscope. After immunofluorescence staining, the chromosomal arrangement and spindle configuration of oocytes were evaluated. The results indicated that TGA decreases the percentage of first polar body formation but does not influence that of germinal vesicle breakdown. TGA induces abnormal chromosomal arrangement and spindle elongation. In conclusion, TGA inhibits in-vitro maturation of mice oocytes and affects chromosomal arrangement and spindle configuration. Furthermore, it probably interferes with biochemical changes that occur during meiosis, resulting in aberrant development.
Improved patient survival for acute myeloid leukemia: a population-based study of 9729 patients diagnosed in Sweden between 1973 and 2005
Authors: Derolf Åsa Rangert , Kristinsson Sigurdur Yngvi , Andersson Therese M.-L. , Landgren Ola , Dickman Paul W. , Björkholm Magnus
Published: November 2008

We evaluated survival patterns for all registered acute myeloid leukemia (AML) patients diagnosed in Sweden in 1973 to 2005 (N = 9729; median age, 69 years). Patients were categorized into 6 age groups and 4 calendar periods (1973-1980, 1981-1988, 1989-1996, and 1997-2005). Relative survival ratios were computed as measures of patient survival. One-year survival improved over time in all age groups, whereas 5- and 10-year survival improved in all age groups, except for patients 80+ years. The 5-year relative survival ratios in the last calendar period were 0.65, 0.58, 0.36, 0.15, 0.05, and 0.01 for the age groups 0 to 18, 19 to 40, 41 to 60, 61 to 70, 71 to 80, and 80+ years, respectively. Intensified chemotherapy, a continuous improvement in supportive care, and allogeneic stem cell transplantation are probably the most important factors contributing to this finding. In contrast, there was no improvement in survival in AML patients with a prior diagnosis of a myelodysplastic syndrome during 1993 to 2005 (n = 219). In conclusion, AML survival has improved during the last decades. However, the majority of AML patients die of their disease and age remains an important predictor of prognosis. New effective agents with a more favorable toxicity profile are needed to improve survival, particularly in the elderly.
Genome-wide and expression analysis of protein phosphatase 2C in rice and Arabidopsis
Authors: Xue Tongtong , Wang Dong , Zhang Shizhong , Ehlting Juergen , Ni Fei , Jakab Stephen , Zheng Chengchao , Zhong Yuan
Published: November 2008

Background

The protein phosphatase 2Cs (PP2Cs) from various organisms have been implicated to act as negative modulators of protein kinase pathways involved in diverse environmental stress responses and developmental processes. A genome-wide overview of the PP2C gene family in plants is not yet available.

Results

A comprehensive computational analysis identified 80 and 78 PP2C genes in Arabidopsis thaliana (AtPP2Cs) and Oryza sativa (OsPP2Cs), respectively, which denotes the PP2C gene family as one of the largest families identified in plants. Phylogenic analysis divided PP2Cs in Arabidopsis and rice into 13 and 11 subfamilies, respectively, which are supported by the analyses of gene structures and protein motifs. Comparative analysis between the PP2C genes in Arabidopsis and rice identified common and lineage-specific subfamilies and potential 'gene birth-and-death' events. Gene duplication analysis reveals that whole genome and chromosomal segment duplications mainly contributed to the expansion of both OsPP2Cs and AtPP2Cs, but tandem or local duplication occurred less frequently in Arabidopsis than rice. Some protein motifs are widespread among the PP2C proteins, whereas some other motifs are specific to only one or two subfamilies. Expression pattern analysis suggests that 1) most PP2C genes play functional roles in multiple tissues in both species, 2) the induced expression of most genes in subfamily A by diverse stimuli indicates their primary role in stress tolerance, especially ABA response, and 3) the expression pattern of subfamily D members suggests that they may constitute positive regulators in ABA-mediated signaling pathways. The analyses of putative upstream regulatory elements by two approaches further support the functions of subfamily A in ABA signaling, and provide insights into the shared and different transcriptional regulation machineries in dicots and monocots.

Conclusion

This comparative genome-wide overview of the PP2C family in Arabidopsis and rice provides insights into the functions and regulatory mechanisms, as well as the evolution and divergence of the PP2C genes in dicots and monocots. Bioinformatics analyses suggest that plant PP2C proteins from different subfamilies participate in distinct signaling pathways. Our results have established a solid foundation for future studies on the functional divergence in different PP2C subfamilies.
Willingness and ability to pay for artemisinin-based combination therapy in rural Tanzania
Authors: Saulo Eleonor C , Forsberg Birger C , Premji Zul , Montgomery Scott M , Björkman Anders
Published: November 2008

Background

The aim of this study was to analyse willingness to pay (WTP) and ability to pay (ATP) for ACT for children below five years of age in a rural setting in Tanzania before the introduction of artemisinin-based combination therapy (ACT) as first-line treatment for uncomplicated malaria. Socio-economic factors associated with WTP and expectations on anti-malaria drugs, including ACT, were also explored.

Methods

Structured interviews and focus group discussions were held with mothers, household heads, health-care workers and village leaders in Ishozi, Gera and Ishunju wards in north-west Tanzania in 2004. Contingent valuation method (CVM) was used with "take-it-or-leave-it" as the eliciting method, expressed as WTP for a full course of ACT for a child and households' opportunity cost of ACT was used to assess ATP. The study included descriptive analyses with multivariate adjustment for potential confounding factors.

Results

Among 265 mothers and household heads, 244 (92%, CI = 88%–95%) were willing to pay Tanzanian Shillings (TSh) 500 (US$ 0.46) for a child's dose of ACT, but only 55% (49%–61%) were willing to pay more than TSh 500. Mothers were more often willing to pay than male household heads (adjusted odds ratio = 2.1, CI = 1.2–3.6). Socio-economic status had no significant effect on WTP. The median annual non-subsidized ACT cost for clinical malaria episodes in an average household was calculated as US$ 6.0, which would represent 0.9% of the average total consumption expenditures as estimated from official data in 2001. The cost of non-subsidized ACT represented 7.0% of reported total annual expenditure on food and 33.0% of total annual expenditure on health care.

"Rapid effect," "no adverse effect" and "inexpensive" were the most desired features of an anti-malarial drug.

Conclusion

WTP for ACT in this study was less than its real cost and a subsidy is, therefore, needed to enable its equitable affordability. The decision taken in Tanzania to subsidize Coartem® fully at governmental health care facilities and at a consumer price of TSh 300–500 (US$ 0.28–0.46) at special designated shops through the programme of Accredited Drug Dispensing Outlets (ADDOs) appears to be well founded.
Evaluation of two counterflow traps for testing behaviour-mediating compounds for the malaria vector Anopheles gambiae s.s. under semi-field conditions in Tanzania
Authors: Schmied Wolfgang H , Takken Willem , Killeen Gerry F , Knols Bart GJ , Smallegange Renate C
Published: November 2008

Background

Evaluation of mosquito responses towards different trap-bait combinations in field trials is a time-consuming process that can be shortened by experiments in contained semi-field systems. Possible use of the BG Sentinel (BGS) trap to sampleAnopheles gambiae s.s.was evaluated. The efficiency of this trap was compared with that of the Mosquito Magnet-X (MM-X) trap, when baited with foot odour alone or combinations of foot odour with carbon dioxide (CO2) or lemongrass as behaviour-modifying cues.

Methods

FemaleAn. gambiae s.s.were released in an experimental flight arena that was placed in a semi-field system and left overnight. Catch rates for the MM-X and BGS traps were recorded. Data were analysed by fitting a generalized linear model to the (n+1) transformed catches.

Results

Both types of traps successfully captured mosquitoes with all odour cues used. When the BGS trap was tested against the MM-X trap in a choice assay with foot odour as bait, the BGS trap caught about three times as many mosquitoes as the MM-X trap (P = 0.002). Adding CO2(500 ml/min) to foot odour increased the number of mosquitoes caught by 268% for the MM-X (P < 0.001) and 34% (P = 0.051) for the BGS trap, compared to foot odour alone. When lemongrass leaves were added to foot odour, mosquito catches were reduced by 39% (BGS, P < 0.001) and 38% (MM-X, P = 0.353), respectively.

Conclusion

The BGS trap shows high potential for field trials due to its simple construction and high catch rate when baited with human foot odour only. However, for rapid screening of different baits in a contained semi-field system, the superior discriminatory power of the MM-X trap is advantageous.
Histopathological and molecular heterogeneity among individuals with dementia associated with Presenilin mutations
Authors: Maarouf Chera L , Daugs Ian D , Spina Salvatore , Vidal Ruben , Kokjohn Tyler A , Patton R Lyle , Kalback Walter M , Luehrs Dean C , Walker Douglas G , Castaño Eduardo M , Beach Thomas G , Ghetti Bernardino , Roher Alex E
Published: November 2008

Background

Mutations in the presenilin (PSEN) genes are associated with early-onset familial Alzheimer's disease (FAD). Biochemical characterizations and comparisons have revealed that many PSEN mutations alter γ-secretase activity to promote accumulation of toxic Aβ42 peptides. In this study, we compared the histopathologic and biochemical profiles of ten FAD cases expressing independent PSEN mutations and determined the degradation patterns of amyloid-β precursor protein (AβPP), Notch, N-cadherin and Erb-B4 by γ-secretase. In addition, the levels of Aβ40/42 peptides were quantified by ELISA.

Results

We observed a wide variation in type, number and distribution of amyloid deposits and neurofibrillary tangles. Four of the ten cases examined exhibited a substantial enrichment in the relative proportions of Aβ40 over Aβ42. The AβPP N-terminal and C-terminal fragments and Tau species, assessed by Western blots and scanning densitometry, also demonstrated a wide variation. The Notch-1 intracellular domain was negligible by Western blotting in seven PSEN cases. There was significant N-cadherin and Erb-B4 peptide heterogeneity among the different PSEN mutations.

Conclusion

These observations imply that missense mutations in PSEN genes can alter a range of key γ-secretase activities to produce an array of subtly different biochemical, neuropathological and clinical manifestations. Beyond the broad common features of dementia, plaques and tangles, the various PSEN mutations resulted in a wide heterogeneity and complexity and differed from sporadic AD.
Cystoid macular oedema in Cogans syndrome-a case report
Authors: Pherwani Anupama , Bansal Shveta , Agrawal Shailesh , Gillow Timothy
Published: November 2008

Introduction

Cogan's Syndrome is typically characterised by a non syphilitic interstitial keratitis (IK), with or without conjunctivitis, iritis or subconjunctival bleeding and progressive sensorineural hearing loss within two years of ocular signs. Atypical ocular manifestations include episcleritis, scleritis, posterior scleritis, retinal artery occlusion, choroiditis, retinal vasculitis, and optic disc oedema. We report a case of Cogan's syndrome in with recurrent cystoid macular oedema was the main feature.

Case presentation

A patient was diagnosed with Cogan's syndrome nearly 2 years after first presentation. He had cystoid macular edema which failed to respond initially to steroid, methotrexate and azothiaprine however resolved after treatment with mycophenolate mofetil.

Conclusion

Cogan's syndrome is rare and presents a challenge in terms of diagnosis and treatment. Recurrent cystoid macular oedema is a unique finding in this condition and can be difficult to control. Multidisciplinary management of this multisystem disorder is vital.
Precision of seafloor gravity and pressure measurements for reservoir monitoring
Authors: Zumberge Mark , Alnes Håvard , Eiken Ola , Sasagawa Glenn , Stenvold Torkjell
Published: November 2008

Changes with gravity over time have proven to be valuable for inferring subsurface density changes associated with production from oil and natural gas reservoirs. Such inferences allow the monitoring of moving fluid fronts in a reservoir and provide an opportunity to optimize production over the life of the reservoir. Our group began making time-lapse seafloor gravity and pressure measurements in 1998. To date, we have surveyed six fields offshore Norway; we have made three repeat surveys at one field and one repeat survey at another. We incorporated a land-gravity sensor into a remotely operated seafloor housing. Three such relative gravity sensors mounted in a single frame are carried by a remotely operated vehicle (ROV) to concrete benchmarks permanently placed on the seafloor. Reference benchmarks sited outside the reservoir boundaries are assumed to provide stable fiducial points. Typical surveys last from a few days to a few weeks and cover from 8 to 80 benchmarks, with multiple observations of each. In our earliest surveys, we obtained an intrasurvey repeatability of approximately [Formula: see text], but recently we have been achieving [Formula: see text] repeatability in gravity and approximately [Formula: see text] in benchmark depth (deduced from simultaneously recorded ambient seawater pressure). We attribute the improved precision to several operational factors, including the use of multiple gravity sensors, frequent benchmark reoccupation, precise relocation and orientation of the sensors, repeated calibrations on land, and minimization of vibrational and thermal perturbations to the sensors. We believe that high-precision time-lapse gravity monitoring can be used to track changes in the height of a gas-water contact in a flooded reservoir, with a precision of a few meters.
Long-term seafloor tidal gravity and pressure observations in the North Sea: Testing and validation of a theoretical tidal model
Authors: Sasagawa Glenn , Zumberge Mark , Eiken Ola
Published: November 2008

Seafloor gravity and pressure measurements for 4D reservoir monitoring require precise models of the time-varying tidal signals. Current seafloor instrumentation can resolve [Formula: see text] in time-lapse gravity differences and [Formula: see text] [Formula: see text] in pressure. To verify model accuracy, a seafloor gravimeter and pressure gauge were operated continuously for [Formula: see text] next to the Troll A gas platform in the North Sea (60.64227° north, 3.72417° east) at a depth of [Formula: see text]. The seafloor gravity and pressure time series were filtered and corrected with estimates from the tidal model, which predicts the solid earth tide, ocean loading, and direct gravitational attraction of the varying water level. The rms difference between the observed tidal gravity signal and the prediction is about [Formula: see text] during periods when there are no surface storms. A slight difference is observed for the direct attraction of the water overhead as computed from the tidal prediction versus that computed from direct seafloor pressure measurements when the entire [Formula: see text] record is analyzed; it shows an rms difference of [Formula: see text], equivalent to [Formula: see text] of water-height variation, yielding a gravity effect of [Formula: see text]. We conclude that existing theoretical tide models in combination with in situ pressure records are sufficiently precise for correcting time-lapse gravity observations.
Reservoir monitoring and characterization using satellite geodetic data: Interferometric synthetic aperture radar observations from the Krechba field, Algeria
Authors: Vasco D. W. , Ferretti Alessandro , Novali Fabrizio
Published: November 2008

Deformation in the material overlying an active reservoir is used to monitor pressure change at depth. A sequence of 11 field estimates allows us to construct a measure of diffusive traveltime throughout a reservoir. The dense distribution of traveltime values means that we can construct an exactly linear inverse problem for reservoir flow properties. Application to interferometric synthetic-aperture radar (InSAR) data gathered over a carbon dioxide [Formula: see text] injection site in Algeria reveals pressure propagation along two northwest-trending corridors. An inversion of the traveltimes indicates the existence of two northwest-trending high-permeability zones. The high-permeability features trend in the same direction as the regional fault and fracture zones. Model-parameter-resolution estimates indicate the features are well resolved.
4D gravity changes associated with the 2005 eruption of Sierra Negra volcano, Galápagos
Authors: Vigouroux Nathalie , Williams-Jones Glyn , Chadwick William , Geist Dennis , Ruiz Andres , Johnson Dan
Published: November 2008

Sierra Negra volcano, the most voluminous shield volcano in the Galápagos archipelago and one of the largest basaltic calderas in the world, erupted on October 22, 2005 after more than [Formula: see text] of quiescence. GPS and satellite radar interferometry (InSAR) monitoring of the deformation of the caldera floor in the months prior to the eruption documented extraordinary inflation rates [Formula: see text]. The total amount of uplift recorded since monitoring began in 1992 approached [Formula: see text] at the center of the caldera over the eight days of the eruption the caldera floor deflated a maximum of 5 m and subsquently renewed its inflation, but at a decelerating rate. To gain insight into the nature of the subsurface mass/density changes associated with the deformation, gravity measurements performed in 2005, 2006, and 2007 are compared to previous measurements from 2001-2002 when the volcano underwent a period of minor deflation and magma withdrawal.The residual gravity decrease between 2001-2002 and 2005 is among the largest ever recorded atan active volcano (−950 μGal) and suggests that inflation was accompanied by a relative density decrease in the magmatic system. Forward modeling of the residual gravity data in 4D (from 2002 to 2005) gives an estimate of the amount of vesiculation in the shallow sill required to explain the observed gravity variations. Geochemical constraints from melt inclusion and satellite remote-sensing data allow us to estimate the pre-eruptive gas content of the magma and place constraints on the thickness of the gas-rich sill necessary to produce the gravity anomalies observed. Results suggest that reasonable sill thicknesses [Formula: see text] and bubble contents (10–50 volume %) can explain the large decrease in residual gravity prior to eruption. Following the eruption (2006 and 2007), the deformation and gravity patterns suggest re-equilibration of the pressure regime in the shallow magma system via a renewed influx of relatively gas-poor magma into the shallow parts of the system.
Monitoring gas production and C O2 injection at the Sleipner field using time-lapse gravimetry
Authors: Alnes Håvard , Eiken Ola , Stenvold Torkjell
Published: November 2008

Thirty seafloor gravity stations have been placed above the carbon dioxide [Formula: see text] injection site and producing gas reservoir at the Sleipner Øst Ty field. Gravity and depth measurements from 2002 and 2005 reveal vertical changes of the permanently deployed benchmarks, probably caused by seafloor erosion and biologic activity (fish). The original gravity data have been reprocessed, resulting in slightly different gravity-change values compared with earlier published results. Observed gravity changes are caused by height variances, gas production and water influx in the Ty Formation, and [Formula: see text] injection in the Utsira Formation. Simultaneous matches to models for these effects have been made. The latest simulation model of the Ty Formation was fitted by permitting a scale factor, and the gravity contribution from the [Formula: see text] plume was determined by using the plume geometry as observed in 4D seismic data and varying the average density. The best-fit vertical gravity gradient is [Formula: see text], and the response from the Ty Formation suggests more water influx than expected in the presurvey simulation model. The best-fit average density of [Formula: see text] is [Formula: see text]. Estimates of the reservoir temperature combined with the equation of state for [Formula: see text] indicate an upper bound on [Formula: see text] density of [Formula: see text]. The gravity data suggest a lower bound of [Formula: see text] at 95% confidence.
The 4D microgravity method for waterflood surveillance: Part IV — Modeling and interpretation of early epoch 4D gravity surveys at Prudhoe Bay, Alaska
Authors: Hare Jennifer L. , Ferguson John F. , Brady Jerry L.
Published: November 2008

Between March 2003 and March 2007, four high-precision 4D absolute microgravity surveys were performed at Prudhoe Bay, Alaska. These surveys are part of an ongoing effort to monitor the progress of a very large water-injection project in the gas cap of the Prudhoe Bay reservoir at a depth of [Formula: see text]. These carefully acquired gravity data must be modeled and interpreted in terms of water movement within the reservoir. A constrained linear inversion scheme was tested on reservoir simulations during the planning and development phase of this project (preinjection). The inver-sion methodology has been applied to data for three epochs (2005–2003, 2006–2003, and 2007–2003), and mass-distribution models have been produced for the reservoir. The time evolution of the water-mass distribution in the reservoir is visualized from these three snapshot models. The waterflood is expanding into the gas cap at the expected rate but is exhibiting nonsymmetric behavior that is consistent with a greater degree of structural control than expected. The waterflood seems to be restrained episodically and guided by fault barriers. These barriers are overcome and fault-bounded blocks filled with water in stages.
Regulation of enteric neuron migration by the gaseous messenger molecules CO and NO
Authors: Knipp Sabine , Bicker Gerd
Published: November 2008

The enteric nervous system (ENS) of insects is a useful model to study cell motility. Using small-molecule compounds to activate or inactivate biosynthetic enzymes, we demonstrate that the gaseous messenger molecules carbon monoxide (CO) and nitric oxide (NO) regulate neuron migration in the locust ENS. CO is produced by heme oxygenase (HO) enzymes and has the potential to signal via the sGC/cGMP pathway. While migrating on the midgut,the enteric neurons express immunoreactivity for HO. Here, we show that inhibition of HO by metalloporphyrins promotes enteric neuron migration in intact locust embryos. Thus, the blocking of enzyme activity results in a gain of function. The suppression of migratory behavior by activation of HO or application of a CO donor strongly implicates the release of CO as an inhibitory signal for neuron migration in vivo. Conversely, inhibition of nitric oxide synthase or application of the extracellular gaseous molecule scavenger hemoglobin reduces cell migration. The cellular distribution of NO and CO biosynthetic enzymes, together with the results of the chemical manipulations in whole embryo culture suggest CO as a modulator of transcellular NO signals during neuronal migration. Thus, we provide the first evidence that CO regulates embryonic nervous system development in a rather simple invertebrate model.
Modelling of variable friction in cold forging
Authors: Cora Ö N , Akkök M , Darendeliler H
Published: November 2008

In metal forming operations, the friction between die and workpiece is a complex phenomenon and has a strong influence on the metal forming parameters and the product quality. This study aims to investigate the effect of friction in cold forging operations using different friction models. In the analyses, the forging operations are simulated using the Coulomb and constant friction models, and the results are compared with the simulation results obtained by using the variable friction models developed by Wanheim—Bay (general friction model) and Levanov, which are integrated into the program. Cylinder upsetting and bolt head forging are numerically simulated and the cylinder upsetting results are compared with the experimental data. The results showed that depending on the workpiece geometry and the contact pressure, the coefficient of friction may change significantly during the process and the constant coefficient of friction may not simulate the actual friction condition in the cold forging process.
The pressure to cause complete contact between elastic—plastic sinusoidal surfaces
Authors: Jackson R L , Krithivasan V , Wilson W E
Published: November 2008

This work examines the average pressure required to cause complete contact between sinusoidal shaped surfaces deforming elastically and plastically. Complete contact is defined as when there are no gaps remaining between the surfaces. The material of the surface is modelled as being elastic—perfectly plastic. This work confirms the results of a recent finite-element ana-lysis using a new semi-analytical model. The results suggest that the pressure required to cause complete contact between surfaces can be much higher than the yield strength or hardness of the surface (in some cases 15 times the yield strength or more). This is because it appears that as the surfaces near complete contact, they begin to act again like an elastic contact. The critical amplitude of a sinusoidal surface below which it will deform entirely in the elastic regime from initial to complete contact is also derived.
Finite-element analysis of layered rolling contacts
Authors: Nikas G K , Sayles R S
Published: November 2008

A fundamental, two-dimensional finite-element analysis (FEA) of coated surfaces in rolling contact is presented with detailed listing of all modelling steps. A large number of basic results from a parametric study has been derived, focusing on the stress analysis and the effect of coatings on the life expectancy of coated surfaces, without actually getting into the ambiguities of fatigue life evaluation. Parameters included in the study are the metallic coating thickness (from zero to 50 μm) and elastic modulus (from 180 to 240 GPa), the Coulomb friction coefficient (0, 0.05, and 0.10) and the endurance limit of the coated substrate. A generalization involves the application of traction to simulate driving or driven wheels. The effect of that traction on the stress results is thoroughly examined. The set of results, summarized in a figure with nine diagrams, assists the quick selection of the optimum parameter values for maximizing coating performance and minimizing the risk of contact fatigue within the design limits used in the study. The model is realistic in that it does not use idealized load distributions in the rolling contact but actual geometrical solids in contact under normal operating conditions, letting the FEA software resolve the loads and stresses, which are subsequently validated.
Combined effects of fluid inertia and non-Newtonian couple stresses on the squeeze film characteristics of a long partial journal bearing
Authors: Lin J-R , Chu L-M , Liang L-J , Hung C-R
Published: November 2008

Combined effects of convective fluid inertial forces and non-Newtonian couple stresses on the of a characteristics squeeze film for a long partial journal bearing are presented. Using Stokes’ microcontinuum theory and the averaged momentum integral principle, a lubrication equation has been derived to investigate the behaviour of the squeeze film between a convex and a concave surface. A closed-form solution for the behaviour of the squeeze film has been derived for long partial journal-bearing system. According to the results, the combined effects of convective inertial forces and non-Newtonian couple stresses provide an increase in the load-carrying capacity and the approaching time, compared with the non-inertial Newtonian-lubricant case. On the whole, the quantitative effects of convective inertial forces and non-Newtonian couple stresses on the improved characteristics are further emphasized for higher squeeze-film Reynolds numbers, non-Newtonian couple-stress parameters, and eccentricity ratios.
Tribological behaviour of three S-containing triazine derivatives and their synergetic effect with zinc dialkyldithiophosphate as additives
Authors: Wu H , Li J , Ren T H , Xie Y
Published: November 2008

The antiwear properties of three S-containing triazine derivatives with different active groups, referred to as TOSS, HOT, and HOMA, as additives in mineral oil, were evaluated using a four-ball friction and wear tester. Their thermal stabilities were investigated and the results suggest that all the synthesized compounds have good thermal stability. It was found that all the three S-containing triazine compounds added to the mineral oil showed rather good tribological behaviour, and the synergism between HOMA and zinc dialkyldithiophosphate (ZDDP) is better than that between ZDDP and HOT/TOSS. The worn surfaces of the steel balls were observed using X-ray photoelectron spectroscope. It is supposed that the synthetic additives adsorb and react with the steel surface during the process and thus generate a surface protective film composed of sulphate, iron oxide, and N-, O-, and S-containing organic compounds, which accounts for the better tribological behaviours of the base stock containing the synthetic additives when compared with the base stock alone.
An approach for determination of lubricant properties at elliptical elastohydrodynamic contacts using a twin-disc test device and a numerical traction model
Authors: Kleemola J , Lehtovaara A
Published: November 2008

High-pressure lubricant properties are important when friction coefficients and power losses are evaluated in elastohydrodynamic (EHL) contacts. An approach was developed to determine the limiting shear stress and actual viscosity properties of lubricants using a numerical traction model based on elliptical EHL contact and traction curves, measured at a wide range of temperatures and pressures with a twin-disc test device. The tests were carried out in pure fluid film at high Hertzian pressures with finely polished surfaces. Each lubricant was tested at 135 test points, where traction coefficients and bulk temperatures were measured. The lubricant parameters in the traction model were adjusted so that the calculated results matched the experimental measurements at all test points. In general, there is a good correlation between the calculated results and the experimental measurements. The influence of pressure on limiting shear stress and actual viscosity is less significant for polyalphaolefin (PAO) oil than for mineral oil.
The influence of roller burnishing process on hardness and roughness of cylindrical polymer surfaces
Authors: El-Tayeb N S M , Low K O , Brevern P V
Published: November 2008

In the present study, the potential for using the roller burnishing process to improve surface roughness and hardness of thermoplastics (acetal homopolymer, POM-H) and thermosets (polyurethane, PU) is investigated. The effect of roller burnishing parameters such as burnishing force, speed, feed, and roller width contact is studied.

The results showed that all burnishing parameters had a controlling effect on surface roughness and hardness of POM-H and PU, but with different degrees. The effect of the roller burnishing process was more pronounced on POM-H compared with PU. Depending on the burnishing parameters, the surface roughness of POM-H and PU was decreased by ∼(32–37) and (28–32) per cent, respectively. Meanwhile, the hardness was marginally increased, i.e. by ∼0.8 and 1 per cent for POM-H and PU, respectively.
Is autism really a coherent syndrome in boys, or girls?
Authors: Skuse David H.
Published: November 2008

This article is a commentary on ‘Fetal testosterone and autistic traits’ (Auyeung et al., 2009).
Caring: Building a psychological disposition in pre‐closing sequences in phone calls with a young adult with a learning disability
Authors: Patterson Anne , Potter Jonathan
Published: November 2008

This article has a joint focus on the way both psychological dispositions and matters of potential disability figure in interaction. The study works with a collection of more than fifty telephone calls between a young adult with a learning disability staying in a residential placement and three other members of her family. It focuses on the closing sections of the telephone calls and in particular how pre‐closing turns may be designed to display caring. This paper analyses three formats through which pre‐closings are delivered; through the use of announcements, interrogatives and imperatives. In each case the pre‐closing commonly includes an account which provides a warrant for the impending termination. Detailed comparative study of the closing sequences in a corpus of mundane phone calls which do not include a disabled member finds very few such accounts. It is suggested that participants draw on accounts in a way that manages the potentially interactionally troubling matter of closing the call and, more specifically, to build the speakers' affiliative, ‘caring’, stance to one another. The analysis is used to consider broader issues about psychology and interaction, family relations and disability.
Complexity in the relationships among the subdimensions of extraversion and job performance in managerial occupations
Authors: Minbashian Amirali , Bright Jim E. H. , Bird Kevin D.
Published: November 2008

The present study investigated differential relationships, nonlinear relationships, and multiplicative relationships among the subdimensions of extraversion (agency and affiliation) and job performance (getting ahead and getting along) for a sample of 179 managers. We found that: (i) agency was positively related to getting ahead performance, whereas affiliation was unrelated to getting ahead; (ii) agency had an inverted‐U relationship with getting along performance; and (iii) there was a multiplicative effect of agency and affiliation on getting along. The findings provide insight into the nature of the relationship between extraversion and managerial performance, the level of breadth at which to represent these variables for optimal prediction and explanation, and the use of extraversion measures for selection purposes.
The PSI-Process Scales. A new measure to assess the intensity and breadth of parasocial processes
Authors: Schramm Holger , Hartmann Tilo
Published: November 2008

Research on parasocial interactions (PSI) and parasocial relationships (PSR) refers back to a tradition of 50 years. However, research on both phenomena still suffers from overlapping definitions and resulting measurements that do not distinguish between PSI and PSR. The present study presents a post-exposure measurement tool (the PSI-Process Scales) that aims to measure PSI instead of PSR. It is derived from a theoretical model that specifically focuses on PSI. Psychometric analyses indicate the tool's high usability. It is capable of displaying both the intensity and the dimensionality of PSI. It can be applied to measure both positive and negative PSI across all TV formats, without changing the item wording. In sum, the PSI-Process-Scales may offer a valuable alternative for researchers in the field, specifically if they want to assess parasocial processes that take place throughout TV exposure.
Spekulationen zum Anfang von Sprache
Authors: Wunderlich Dieter
Published: November 2008

The article considers four scenarios along the way human language developed, the neolithic transition from nomadic to agricultural societies, the upper paleolithic revolution when a sudden proliferation of art, tools and complex social organization took place, the emergence ofhomosapiens possibly supported by the rise of the vocalization ability, and the emergence ofhomo ergaster/erectusaccompanied with a rapid growth of the brain, and discusses in what respect these different scenarios contribute to the linguistic capacity of modern man. In particular, the thesis offered within the Minimalist Program that the language faculty in the narrow sense is a product of the upper paleolithic revolution is questioned. It is argued, instead, for a different view, namely that early morphology evolved as a reinterpretation of phonological alternations just in time when phonological features were developed, whereas a considerable amount of syntax proper evolved only when the neolithic transition had changed the circumstances of communication. However, the faculty of combining meaningful elements, as well as the faculty of recursion, may well have developed quite earlier at the time ofhomo erectus.
Martíín Fierro: A Uruguayan Classic
Authors: mangino marcela baruch
Published: November 2008

The popular Uruguayan dessert, Martíín Fierro, takes its name from the famous hero of Argentine writer Joséé Hernandez's epic poem. The poem is regarded as a masterpiece of the gauchesque genre and a symbol of Argentine (and Uruguayan) identity. Hernáández's past as politician, poet and writer is explored in relation to his work, in particular, the epic poem, Martíín Fierro and The Return of Martíín Fierro. The Martíín Fierro dessert evolved from Hernandez's preference for a popular Argentinean dessert of cheese and sweet potato called "Vigilante" to the Uruguayan version of cheese with quince paste, and was thus named in his honor. The influence of the Spanish and Swiss in the history of the dessert's main ingredients, Colonia cheese and quince paste, highlights the adaptation of the Uruguayan cuisine to European traditions, and the adoption of the gaucho literary hero as their own underscores Uruguayan identity with the (Southern cone) region.
Perceiving Conductors' Expressive Gestures from Different Visual Perspectives. An Exploratory Continuous Response Study
Authors: Wöllner Clemens , Auhagen Wolfgang
Published: November 2008

INSIGHTS INTO MUSICAL CONDUCTING are traditionally derived from educational manuals and from interviews with conductors about their intuitive knowledge. Conducting as a form of highly specialized nonverbal communication has scarcely been studied empirically up to now. We investigated the perception of expressive movements used by conductors, as seen from three different positions with a multimodal, repeated-measures design. Observers with music training evaluated video recordings of several conductors with continuous and retrospective measures. Results indicate that watching the conductors from positions of woodwind players and first violinists (frontal and left-hand side) is perceptually more informative compared to the celli/double bass position (right-hand side). Observers gained specific information about the conductors' expressive musical intentions even in visual-only video sequences. Crosscorrelations between quantitative characteristics of conductors' movements and observers' continuous expressiveness responses show a tendency for different response time lags. These time lags are related to individual conductors' general affective behavior.
Range of Tuning for Tones With and Without Vibrato
Authors: Besouw Rachel M. Van , Brereton Jude S. , Howard David M.
Published: November 2008

PREVIOUS STUDIES ON VIBRATO PITCH HAVE attempted to determine the "principal pitch" of vibrato tones and not the range of tuning for such tones in a melodic context. This study investigates the range of acceptable tuning (RAT) for tones with and without vibrato, using repeating ascending and descending three-tone arpeggios. The second tone in each sequence was modulated or unmodulated with an initial pitch that was flat or sharp. With each repetition the pitch of the second tone increased or decreased by 3 cents depending upon the initial pitch condition. Participants indicated when they perceived the second tone to be in tune and out of tune. The RAT for vibrato tones was approximately 10 cents greater than for unmodulated tones. This is largely due to the lower RAT limit, indicating that the carrier frequency of vibrato tones can be 10 cents flatter than the fundamental frequency of an unmodulated tone.
A Review and Updated Assessment of Florida's Anadromous Shads: American Shad and Hickory Shad
Authors: McBride Richard S. , Holder Jay C.
Published: November 2008

This paper reviews the history of fishing, regulations, and stock assessments for Florida's anadromous shad species—American shad Alosa sapidissima and hickory shad A. mediocris—and assesses their status in Florida's St. Johns River based on a creel survey and an electrofishing survey. Historically, these anadromous shads constituted an important fishery in Florida. Landings were first reported in the 1860s, and scientific assessments occurred in the 1950s, 1960s, and early 1970s. Netting restrictions effectively ended the commercial fishery in the 1990s. We used recreational catch rates as a proxy for stock size and found it to be low but stable during 1993–2005. The mean length of American shad was significantly less during 2002–2005 than it was historically (1958), and the recent proportions of female American and hickory shad were significantly lower than the historical proportions. These data were interpreted as demonstrating a negative, but perhaps only an historical, effect of fishing. The rebuilding of Florida's anadromous shad stocks via fishing regulations was not evident; this may require more time, or perhaps factors other than fishing are interfering with the rebuilding process.
Influence of Gravel Mining and Other Factors on Detection Probabilities of Coastal Plain Fishes in the Mobile River Basin, Alabama
Authors: Hayer Cari‐Ann , Irwin Elise R.
Published: November 2008

We used an information‐theoretic approach to examine the variation in detection probabilities for 87 Piedmont and Coastal Plain fishes in relation to instream gravel mining in four Alabama streams of the Mobile River drainage. Biotic and abiotic variables were also included in candidate models. Detection probabilities were heterogeneous across species and varied with habitat type, stream, season, and water quality. Instream gravel mining influenced the variation in detection probabilities for 38% of the species collected, probably because it led to habitat loss and increased sedimentation. Higher detection probabilities were apparent at unmined sites than at mined sites for 78% of the species for which gravel mining was shown to influence detection probabilities, indicating potential negative impacts to these species. Physical and chemical attributes also explained the variation in detection probabilities for many species. These results indicate that anthropogenic impacts can affect detection probabilities for fishes, and such variation should be considered when developing monitoring programs or routine sampling protocols.