bluuebunny/crossref_metadata_2025 huggingface dataset:
Three‐dimensional holograph vector of atomic interaction field (3D‐HoVAIF): a novel rotation–translation invariant 3D structure descriptor and its applications to peptides
Authors: Tian Feifei , Zhou Peng , Lv Fenglin , Song Rong , Li Zhiliang
Published: July 2007

Quantitative structure–activity relationship (QSAR) study, important in drug design, mainly involves two aspects, molecular structural characterization (MSC) and construction of a statistical model. MSC focuses on transforming molecular structural and property characteristics into a group of numerical codes, dedicated to minimizing information loss during this process. In this context, common atoms in organic compounds are classified according to their families in the periodic table, and hybridization states, and on the basis of these, three nonbonding interactions (i.e. electrostatic, van der Waals and hydrophobic) are calculated, ultimately resulting in a new rotation–translation invariant, 3D‐MSC, as a three‐dimensional holograph vector of atomic interaction field (3D‐HoVAIF). By applying 3D‐HoVAIF to QSAR studies on two classical peptides including 58 angiotensin‐converting enzyme (ACE) inhibitors and 48 bitter‐tasting dipeptides, we get two excellent genetic algorithm‐partial least squares (GA‐PLS) models, with statistics r2, q2, root mean square error (RMSEE), and root mean square error of cross‐validation (RMSCV) of 0.857, 0.811, 0.376, and 0.432 for ACE inhibitors and 0.940, 0.892, 0.153 and 0.205 for bitter‐tasting dipeptides, respectively. By equally dividing the two datasets into training and test sets by D‐optimal, the 3D‐HoVAIF approach undergoes rigorous statistical validation. Furthermore, the superior performance of 3D‐HoVAIF is confirmed in comparison with two other peptide MSC approaches referring to z‐scale and ISA‐ECI. For 58 ACE inhibitors, the GA‐PLS model yields two principal components, with the following statistics: r2 = 0.893, q2 = 0.824, RMSEE = 0.349, RMSCV = 0.425, $q_{\rm {ext}}^{2} = 0.739$, $r_{\rm {ext}}^{2} = 0.784$, $r_{0, {\rm {ext}}}^{2} = 0.781$, $r_{0, ext}^{'2} = 0.779$, k = 0.962, k′ = 1.019, and RMSEP = 0.460; for 48 bitter‐tasting dipeptides, three principal components resulted, with the statistics as: r2 = 0.950, q2 = 0.893, RMSEE = 0.152, RMSCV = 0.222, $q_{ext}^{2} = 0.875$, $r_{ext}^{2} = 0.919$, $r_{0, ext}^{2} = 0.919$, $r_{0, ext}^{'2} = 0.919$, k = 1.018, k′ = 0.974, and RMSEP = 0.198. In addition, the relationship of ACE‐inhibiting activities with bitter‐tasting thresholds has been investigated by applying the above‐constructed models to predictions on 400 theoretically possible dipeptides. Through analysis, the ACE‐inhibiting activities are found to be prominently related to bitter‐tasting intensities. Thus, it is deemed to be difficult to find such dipeptides that simultaneously satisfy pharmacodynamic action (high ACE‐inhibiting activities) and comfortable tastes, suggesting that active components of dipeptides that are served as functional food to lower blood pressure are not very ideal. Copyright © 2007 European Peptide Society and John Wiley & Sons, Ltd.
Topological Electronegativity Index and Its Application – I. Ionization Potentials of Alkyl Groups and Alkyl Halides
Authors: Cao Chenzhong , Luo Jinhua
Published: July 2007

A Topological Electronegativity Index (TEI) for alkyl group was developed, based on the bond adjacency matrix of the radical atom. Taking the radical atom and the adjacency atoms (or groups) as the vertices of molecular graph of the alkyl group, the bond adjacency matrix was constructed, in which the diagonal elements were assigned the Pauling electronegativity of the atom (or group), and the off‐diagonal elements were assigned values 1 or 0. The off‐diagonal elements represent the bond connections: that is when the two atoms (or groups) connect with each other, it is 1; otherwise is 0. From the matrix, the eigenvalues were obtained and its geometric mean value was considered as the TEI of an alkyl. The calculated TEI has good correlation with its experimental ionization potential. Further, the TEI was applied to correlate with the ionization potentials of alkyl halides and substituted ethenes, and to correlate with the Bond Dissociation Energies (BDEs) of the CiH bonds in alkanes.
Success with improvement — requires the right roles to be enacted — in symbiosis
Authors: Johansen Jørn , Pries‐Heje Jan
Published: July 2007

Success in process improvement (PI) depends on the viewpoint and the observer. The same process can be seen as a success from one viewpoint and an utter failure from another. In this article, we report the results of a large Danish research project that set out to study success and failure in product innovation and PI projects, using a large interview study and grounded theory analysis as the research approach. One main outcome of the research project was a model and a method — called ImprovAbility — that can be used to increase an organization's ability to succeed. Another outcome was detailed findings about the different roles in PI. The roles we identify are that of project members, project managers, process owners, project organization, top managers, involved experts and users. They all have different roles in relation to the organizational goal: improving and becoming better at improving. They are also involved in defining requirements and providing and obtaining knowledge in different ways, and they focus on different things, face different problems, and are happy about different solutions. The core of the article reports these findings and discusses how one can use diversity to increase the chance of success in PI. Copyright © 2007 John Wiley & Sons, Ltd.
Merit aid: The practice of giving money to those who do not need it
Authors: Brown Raymond
Published: July 2007

This chapter examines some of the salient features of merit‐based student financial aid. The author explores the role of merit aid in college admission and how it is used in today's competitive market.
Annotated bibliography
Authors: Gupta Gaurav
Published: July 2007

This chapter offers the reader an annotated bibliography of current issues facing admission and financial aid officers. The section outlines additional readings that supplement the chapters in this volume.
Optimum design of multistory uniform structures with simple eccentricity
Authors: Georgoussis George K.
Published: July 2007

A simple formula is presented to predict the conditions under which the degree of translational–torsional coupling of mixed‐bent‐type multistory eccentric buildings is insignificant and can be neglected in the structural design of such buildings. The formula is applicable to monosymmetric structures consisting of walls and rigid frames that are uniform over the height of the building. The derivation of the formula is based on the technique of representing discrete‐member structural models with an equivalent continuum medium and on the findings of an earlier paper presented by the writer, that in eccentric mixed‐bent‐type structures, under certain circumstances, the eccentricity of the wall system opposes the eccentricity of the frame system and that results in an effectively uncoupled building structure. The accuracy of the formula is examined by means of a parametric study that includes common types of wall‐frame monosymmetric structures and comparisons are made with the results obtained by three‐dimensional finite element dynamic analyses of discrete member models. Copyright © 2007 John Wiley & Sons, Ltd.
Structure and aggregation in dilate solution of surface active agents
Authors: Klevens H. B.
Published: July 2007

Critical micelle concentrations (CMC) are shown to depend on chain length. All straight chain saturated surface active agents of equal ion length have approximately the same CMC. Thus a C13 fatty acid soap, a C12 sulfonate, a C11 sulfate, and a C12 ammonium chloride have CMC values of 0.010–0.014M. Values of CMC are not changed to any extent by substitution near the hydrophilic head of one, two, or three groups, even as large as hydroxyethyl, in place of the amine hydrogens in the cationic detergents. However substitution with dihydroxypropyl groups has a marked effect on association in C12 but not in the C16 series, indicating that the relative lengths of the two chains must be considered as an important factor in association. This is well illustrated in the dialkylsulfosuccinate series, and in a tetradecane sulfate series in which the −SO4Na group was progressively moved down the chain, particularly when the branched chain compounds are compared with the corresponding straight chain detergents of length equal to the maximum length from the charged head to the ultimate carbon atom. Introduction of double bonds causes a small but definite increase in CMC whereas polar substitution in the chain results in a marked increase in CMC. Possible micelle structures are discussed in the light of these association phenomena, and it is concluded that the assignment of a definite size and shape to micelles appears at the present time to be slightly premature. However if one includes the concept of relative order‐disorder in the micelle as one of the factors, in addition to chain length, type of detergent, and environment, which are important in micelle structure, it is possible to explain partially the apparent marked differences which have been reported for micelles of different surface active agents.
An inexpensive soap stock conversion plant
Authors: Levin Herman , Swearingen J. S.
Published: July 2007

The design of an inexpensive, small scale plant for converting soap stock to crude fatty acid has been described. It has a capacity for producing 6 tons of product (90–95 wt. % fatty acid) per day from 4,000 gallons of soap stock feed (35–40 wt. % fatty acid). Installed at a cost of $11,000, the unit investment has proved to range between $7 and $8 per annual ton of product. Operating continuously for the past two years since construction (at varying percentages of capacity), total processing costs have averaged 0.75c per pound of fatty acid product.

This plant design is presented to demonstrate that a small scale and marginal operation, such as soap stock conversion, can be carried out both economically and competitively when preceded by sound engineering analysis.
Factor for converting elemental phosphorus to acetone insolubles in crude soybean oil
Authors: List G. R. , Heakin A. J. , Evans CD. , Black L. T. , Mounts T. L.
Published: July 2007

The official AOCS method CA 12‐55 contains a factor of 30 in an equation for relating the phosphorus content of crude soybean oil to equivalent phosphatide. The historical derivation of this factor is discussed. The mean value was calculated to be 31.7 ±0.9 by correlation of phosphorus content with acetone insolubles in six lots of crude oil.
Distribution of Na+/I– Symporter in Thyroid Cancers in an Iodine‐deficient Population: An Immunohistochemical Study
Authors: Mishra Anjali , Pal Lily , Mishra Saroj Kanta
Published: July 2007

Background

There are significant differences in the prevalence and behavior of differentiated thyroid cancers (DTC) in the iodine‐deficient areas (IDA) and iodine‐sufficient areas (ISA) of the world. The sodium iodide symporter (NIS), mediates active transport of iodide across the basolateral aspect of the thyroid follicular cell. However, no study had specifically addressed the issue of expression of sodium iodide symporter (NIS) in thyroid cancer specimens from IDA. The aim of the present study was to find an expression pattern of NIS in DTC in an iodine‐deficient population, and to correlate it with histological subtypes, i.e., papillary carcinoma (PTC), follicular carcinoma (FTC), poorly differentiated carcinoma (PDTC), as well as with clinicopathological risk factors and iodine (131I) uptake by distant metastases.

Methods

Immunohistochemistry was carried out in 39 cases of thyroid cancer (41 samples) including PTC (15), FTC (10), PDTC (9), anaplastic cancer (5), and resected metastases (2). Expression was correlated with the patient’s age, sex, tumor size, presence or absence of extrathyroidal invasion, distant and lymph node metastases, and whole body radioiodine scan.

Results

Overall, 61.8% of DTC patients showed NIS expression. There was no significant difference in expression rate between PTC (73.3%) and FTC (70.0%). However, expression was significantly less in PDTC (33.3%). There was no correlation between NIS expression and any clinicopathological risk factor (p >. 05). The results of NIS expression were not concordant with 131I uptake by metastases in 4 of 10 cases. 131I uptake was absent in one case despite the finding that a metastatic site itself showed NIS expression in that case, whereas in the remaining 9 cases 131I uptake was present although three cases did not show NIS expression.

Conclusions

In our experience, overall expression of NIS was comparable to other studies from ISA. We conclude that expression may not accurately predict radioactive iodine (RAI) uptake by metastases.
Artificial nest predation rates vary among habitats in the Australian monsoon tropics
Authors: Noske Richard A. , Fischer Sarah , Brook Barry W.
Published: July 2007

Rates of nest predation have frequently been shown to differ between fragmented and unfragmented habitats, but have rarely been compared among natural habitats in the same geographic region. In this study, artificial nests of two types (open cup and domed) were placed in four habitats (mangroves, monsoon rainforests, eucalypt woodlands and paperbark swamps) over 12 months in three localities near Darwin in the Australian monsoon tropics to determine the effects of habitat, season and nest type on the rate of nest predation. A quail egg and a similarly coloured plasticine egg were placed in each nest. Habitat had a strong effect on nest predation rates, with nests in mangroves experiencing predation rates more than four times higher than those in eucalypt woodlands and paperbark swamps. Despite the strong rainfall seasonality of the region, there was no consistent seasonal variation in nest predation rates. Nest type also had little influence on predation rates, except in paperbark swamps where open cup nests suffered a higher predation rate than domed nests. The study indicates that generalised nest predation rates for tropical regions, even for small areas (e.g. <17 km radius), might overlook substantial variation between habitats. Such variation confounds purported differences in nest predation rates between tropical and temperate regions.
Short‐term changes in plans to drink and importance of positive and negative alcohol consequences
Authors: Patrick Megan E. , Maggs Jennifer L.
Published: July 2007

Experienced consequences predicted short‐term changes in alcohol use plans and perceptions of the importance of alcohol‐related consequences. Participants were 176 traditionally aged first‐year university students who completed a 10‐week telephone diary study (total weeks=1735). In multi‐level models, men and students who experienced more positive and negative consequences on average planned to drink more and rated avoiding negative consequences as less important. Students who experienced more positive consequences rated them as more important (between‐person analyses). Following weeks of experiencing relatively more positive drinking consequences, students planned to drink more and rated experiencing positive consequences as more important for the subsequent week (within‐person analyses). Challenges for intervening in the ongoing formation of anticipatory cognitions regarding alcohol use are discussed.
Paleoecological analyses of lake sediments reveal prehistoric human impact on forests at anthony island UNESCO World Heritage Site, Queen Charlotte Islands (Haida Gwaii), Canada
Authors: Lacourse Terri , Mathewes Rolf W. , Hebda Richard J.
Published: July 2007

Pollen and plant macrofossil analyses of lake sediments from Anthony Island in the southern Queen Charlotte Islands (Haida Gwaii), British Columbia, reveal 1800 yr of relatively stable temperate rainforest vegetation. Cupressaceae (cedar) pollen percentages and accumulation rates decline about 1000 cal yr BP, coincident with occupation of the island by Haida peoples, who use Thuja plicata (western red cedar) almost exclusively for house construction, dugout canoes, monumental poles, and many other items. Anthropogenic disturbance offers the most likely explanation for the decline of T. plicata.
Streamline topology in the near wake of a circular cylinder at moderate Reynolds numbers
Authors: BRØNS MORTEN , JAKOBSEN BO , NISS KRISTINE , BISGAARD ANDERS V. , VOIGT LARS K.
Published: July 2007

For the flow around a circular cylinder, the steady flow changes its topology at a Reynolds number around 6 where the flow separates and a symmetric double separation zone is created. At the bifurcation point, the flow topology is locally degenerate, and by a bifurcation analysis we find all possible streamline patterns which can occur as perturbations of this flow. We show that there is no a priori topological limitation from further assuming that the flow fulfils the steady Navier–Stokes equations or from assuming that a Hopf bifurcation occurs close to the degenerate flow.

The steady flow around a circular cylinder experiences a Hopf bifurcation for a Reynolds number about 45–49. Assuming that this Reynolds number is so close to the value where the steady separation occurs that the flow here can be considered a perturbation of the degenerate flow, the topological bifurcation diagram will contain all possible instantaneous streamline patterns in the periodic regime right after the Hopf bifurcation. On the basis of the spatial and temporal symmetry associated with the circular cylinder and the structure of the topological bifurcation diagram, two periodic scenarios of instantaneous streamline patterns are conjectured. We confirm numerically the existence of these scenarios, and find that the first scenario exists only in a narrow range after the Hopf bifurcation whereas the second one persists through the entire range of Re where the flow can be considered two-dimensional. Our results corroborate previous experimental and computational results.
The influence of viscosity on the frozen wave instability: theory and experiment
Authors: TALIB EMMA , JALIKOP SHREYAS V. , JUEL ANNE
Published: July 2007

We present the results of an experimental and linear stability study of the influence of viscosity on the frozen wave (FW) instability, which arises when a vessel containing stably stratified layers of immiscible liquids is oscillated horizontally. Our linear stability model consists of two superposed fluid layers of arbitrary viscosities and infinite lateral extent, subject to horizontal oscillation. The effect of the endwalls of the experimental vessel is simulated by enforcing the conservation of horizontal volume flux, so that the base flow consists of counterflowing layers.

We perform experiments with four pairs of fluids, keeping the viscosity of the lower layer (ν1) constant, and increasing the viscosity of the upper layer (ν2), so that 1.02 × 102 ≤ N1 = ν2/ν1 ≤ 1.21 × 104. We find excellent quantitative agreement between theory and experiment despite the simple model geometry, for both the critical onset parameter and wavenumber of the FW. We show that the model of lyubimov:1987 (Fluid Dyn. vol. 86, 1987, p. 849), which is valid in the limit of inviscid fluids, consistently underestimates the instability threshold for fluids of equal viscosity, but generally overestimates the threshold for fluids of unequal viscosity. We extend the experimental parameter range numerically to viscosity contrasts 1 ≤ N1 ≤ 6 × 104 and identify four regions of N1 where qualitatively different dynamics occur, which are reflected in the non-monotonic dependence of the most unstable wavenumber and the critical amplitude on N1. In particular, we find that increasing the viscosity contrast between the layers leads to destabilization over a wide range of N1, 10 ≤ N1 ≤ 8 × 103. The intricate dependence of the instability on viscosity contrast is due to considerable changes in the time-averaged perturbation vorticity distribution near the interface.
Mass flow rate measurements in a microchannel, from hydrodynamic to near free molecular regimes
Authors: EWART TIMOTHÉE , PERRIER PIERRE , GRAUR IRINA A. , MÉOLANS J. GILBERT
Published: July 2007

Helium mass flow rates in a microchannel were measured, for a wide Knudsen-number range, in isothermal steady conditions. The flow Knudsen numbers, considered here, cover the range from continuum slip regime to the near free molecular regime. We used a single-channel system involved in an experimental platform more powerful than those previously used. The experimental errors and uncertainties were accurately investigated and estimated. In the continuum slip regime, it was found that the first-order approach is pertinent for Knudsen number between 0.03 and 0.3. Moreover, the slip coefficient was deduced by comparing the experiments with the theoretical first-order slip continuum approach. For Knudsen number between 0.03 and 0.7, a polynomial second-power form is proposed for the mass flow rate expression. Otherwise, the experimental results on the mass flow rate were compared with theoretical values calculated from kinetic approaches over the 0.03–50 Knudsen number range, and an overall agreement appears through the comparison. It was also found, when the Knudsen number increased, that the wall influence on measurement occurred first through the accommodation process in the transition regime followed by the wall influence through the aspect ratio in the free molecular regime.
Variable-density miscible displacements in a vertical Hele-Shaw cell: linear stability
Authors: GOYAL N. , PICHLER H. , MEIBURG E.
Published: July 2007

A computational study based on the Stokes equations is conducted to investigate the effects of gravitational forces on miscible displacements in vertical Hele-Shaw cells. Nonlinear simulations provide the quasi-steady displacement fronts in the gap of the cell, whose stability to spanwise perturbations is subsequently examined by means of a linear stability analysis. The two-dimensional simulations indicate a marked thickening (thinning) and slowing down (speeding up) of the displacement front for flows stabilized (destabilized) by gravity. For the range investigated, the tip velocity is found to vary linearly with the gravity parameter. Strongly stable density stratifications lead to the emergence of flow patterns with spreading fronts, and to the emergence of a secondary needle-shaped finger, similar to earlier observations for capillary tube flows. In order to investigate the transition between viscously driven and purely gravitational instabilities, a comparison is presented between displacement flows and gravity-driven flows without net displacements.

The linear stability analysis shows that both the growth rate and the dominant wavenumber depend only weakly on the Péclet number. The growth rate varies strongly with the gravity parameter, so that even a moderately stable density stratification can stabilize the displacement. Both the growth rate and the dominant wavelength increase with the viscosity ratio. For unstable density stratifications, the dominant wavelength is nearly independent of the gravity parameter, while it increases strongly for stable density stratifications. Finally, the kinematic wave theory of Lajeunesse et al. (J. Fluid Mech. vol. 398, 1999, p. 299) is seen to capture the stability limit quite accurately, while the Darcy analysis misses important aspects of the instability.
Unbalanced instabilities of rapidly rotating stratified shear flows
Authors: VANNESTE J. , YAVNEH I.
Published: July 2007

The linear stability of a rotating stratified inviscid horizontal plane Couette flow in a channel is studied in the limit of strong rotation and stratification. Two dimensionless parameters characterize the flow: the Rossby number ε, defined as the ratio of the shear to the Coriolis frequency and assumed small, and the ratio s of the Coriolis frequency to the buoyancy frequency, assumed to satisfy s ≤ 1. An energy argument is used to show that unstable perturbations must have large, O(ε−1), wavenumbers. This motivates the use of a WKB-approach which, in the first instance, provides an approximation for the dispersion relation of the various waves that can propagate in the flow. These are Kelvin waves, trapped near the channel walls, and inertia–gravity waves with or without turning points.

Although the waves have real phase speeds to all algebraic orders in ε, we establish that the flow is unconditionally unstable. This is the result of linear resonances between waves with oppositely signed wave momenta. Three modes of instabilities are identified, corresponding to the resonance between (i) a pair of Kelvin waves, (ii) a Kelvin wave and an inertia–gravity wave, and (iii) a pair of inertia–gravity waves. Whilst all three modes of instability are active when the Couette flow is anticyclonic, mode (iii) is the only possible instability mechanism when the flow is cyclonic.

We derive asymptotic estimates for the instability growth rates. These are exponentially small in ε, i.e. of the form Im ω = a exp(-Ψ/ε) for some positive constants a and Ψ. For the Kelvin-wave instabilities (i), we obtain analytic expressions for a and Ψ; the maximum growth rate, in particular, corresponds to Ψ = 2. For the other types of instabilities, we make the simplifying assumption s ≪ 1 and find that the maximum growth rates correspond to Ψ=2.80 for (ii) and Ψ= π for (iii). The asymptotic results are confirmed by numerical computations. These reveal, in particular, that the instabilities (iii) have much smaller growth rates in cyclonic flows than in anticyclonic flows, even though Ψ = π in both cases.

Our results highlight the limitations of the so-called balanced models, widely used in geophysical fluid dynamics, which filter out Kelvin and inertia–gravity waves and hence predict the stability of Couette flow. They are also relevant to the stability of Taylor–Couette flows and of astrophysical accretion disks.
Direct numerical simulation of the turbulent boundary layer over a rod-roughened wall
Authors: LEE SEUNG-HYUN , SUNG HYUNG JIN
Published: July 2007

The effects of surface roughness on a spatially developing turbulent boundary layer (TBL) are investigated by performing direct numerical simulations of TBLs over rough and smooth walls. The Reynolds number based on the momentum thickness was varied in the range Reθ = 300 ∼ 1400. The roughness elements were periodically arranged two-dimensional spanwise rods, and the roughness height was k = 1.5θin, where θin is the momentum thickness at the inlet, which corresponds to k/δ = 0.045 ∼ 0.125, δ being the boundary layer thickness. To avoid generating a rough-wall inflow, which is prohibitively difficult, a step change from smooth to rough was placed 80θin downstream from the inlet. The spatially developing characteristics of the rough-wall TBL were examined. Along the streamwise direction, the friction velocity approached a constant value, and self-preserving forms of the turbulent Reynolds stress tensors were obtained. Introduction of the roughness elements affected the turbulent stress not only in the roughness sublayer but also in the outer layer. Despite the roughness-induced increase of the turbulent Reynolds stress tensors in the outer layer, the roughness had only a relatively small effect on the anisotropic Reynolds stress tensor in the outer layer. Inspection of the triple products of the velocity fluctuations revealed that introducing the roughness elements onto the smooth wall had a marked effect on vertical turbulent transport across the whole TBL. By contrast, good surface similarity in the outer layer was obtained for the third-order moments of the velocity fluctuations.
Mixing at the interface between two fluids in porous media: a boundary-layer solution
Authors: PASTER AMIR , DAGAN GEDEON
Published: July 2007

A lighter fluid (fresh water) flows steadily above a body of a standing heavier one (sea water) in a porous medium. If mixing by transverse pore-scale dispersion is neglected, a sharp interface separates the two fluids. Solutions for interface problems have been derived in the past, particularly for the case of interest here: sea-water intrusion in coastal aquifers. The Péclet number characterizing mixing, Pe = b′/αT where b′ is the aquifer thickness and αT is transverse dispersivity, is generally much larger than unity. Mixing is nevertheless important in a few applications, particularly in the development of a transition layer near the interface and in entrainment of sea water within this layer. The equations of flow and transport in the mixing zone comprise the unknown flux, pressure and concentration fields, which cannot be separated owing to the presence of density in the gravity term. They are nonlinear because of the advective term and the dependence of the dispersion coefficients on flux, the latter making the problem different from that of mixing between streams in laminar viscous flow.

The aim of the study is to solve the mixing-layer problem for sea-water intrusion by using a boundary-layer approximation, which was used in the past for the case of uniform flow of the upper fluid, whereas here the two-dimensional flux field is non-uniform. The boundary-layer solution is obtained in a few steps: (i) analytical potential flow solution of the upper fluid above a sharp interface is adopted; (ii) the equations are reformulated with the potential and streamfunction of this flow serving as independent variables; (iii) boundary-layer approximate equations are formulated in terms of these variables; and (iv) simple analytical solutions are obtained by the von Káarmán integral method. The agreement with an existing boundary-layer solution for uniform flow is excellent, and similarly for a solution of a particular case of sea-water intrusion with a variable-density code. The present solution may serve for estimating the thickness of the mixing layer and the rate of sea-water entrainment in applications, as well as a benchmark for more complex problems.
An electropalatographic and acoustic study of affricates and fricatives in two Catalan dialects
Authors: Recasens Daniel , Espinosa Aina
Published: July 2007

The present study is an electropalatographic and acoustic investigation of the fricatives /s, f/ and the affricates /ts, dz, tf, d[zcy ]/ based on data from five speakers of Majorcan Catalan and five speakers of Valencian Catalan. Results show that the articulatory characteristics of fricatives and affricates agree in several respects: the sounds traditionally labeled /f/ and /tf, d[zcy ]/ are alveolopalatal, and are articulated at a less anterior location, are less constricted and show more dorsopalatal contact than the alveolars /s/ and /ts, dz/; the two place categories are closer to each other in Valencian than in Majorcan. Compared to voiceless affricates, voiced affricates are more anterior and more constricted, and show less dorsopalatal contact. Data also show that closure location for /tf, d[zcy ]/ occurs at the alveolar zone, and that articulatory differences among affricates are better specified at frication than at closure. Strict homorganicity between the stop and frication components of affricates appears to hold provided that constriction location at frication is compared with place of articulation at closure offset. In comparison to voiceless affricates, voiced affricates were shorter, and exhibited a longer closure and a shorter frication period, in Majorcan; in Valencian, on the other hand, closures were shortest for /d[zcy ]/, and frication was systematically longer for voiceless vs. voiced affricates. These duration data appear to conform to a universal trend in Valencian but not in Majorcan where voiced affricates are lengthened intentionally. In both Catalan dialects, vowel duration varies inversely with the duration of the affricate and of its closure and frication components. The implications of these articulatory and duration characteristics for the interpretation of sound changes affecting affricates, i.e. place merging, lenition and devoicing, are discussed.
Land conservation policies and income distribution: who bears the burden of our environmental efforts?
Authors: ROBALINO JUAN A.
Published: July 2007

We analyze the impact of land conservation policies on income distribution using a two-sector model. We find that conservation policies can have important distributional effects through changes in rents and wages. We show how aggregate rents rise when protected areas increase despite the reduction of land availability. Simultaneously, real wages decrease in consequence of higher agricultural prices. These distributional changes also affect the efficiency of conservation policies since higher rents lead to deforestation elsewhere. Results suggest that Pareto improving compensation should also be aimed at agricultural workers.
Cost-effective species conservation: an application to Huemul (Hippocamelus bisulcus) in Chile
Authors: ISAZA CARLOS ADRIÁN SALDARRIAGA , BOFILL WALTER GÓMEZ , CABRERA HUGO SALGADO
Published: July 2007

In this paper we study the cost-effective allocation of the land in the Cordilleran Protection Area (CPA), Region VIII, Chile, for the conservation of a highly threatened species: the Huemul (Hippocamelus bisulcus). Using a production possibilities frontier (PPF) approach, a linear programming optimization model for a ten-year time period is proposed. Our model takes into account both the preferences of the species for different habitats and the opportunity cost of the land. We evaluate different possibilities of land allocation and identify cost-effective alternatives in the provision of both conservation and income.

The results confirm the hypothesis that both the population of Huemul and income from economic activities can be increased compared with current levels. Therefore the current allocation of the land in the CPA is not cost-effective.
Negative Priming as a Memory Phenomenon
Authors: Mayr Susanne , Buchner Axel
Published: July 2007

Abstract. Reactions to recently ignored stimuli are slowed down or more error prone when compared to reactions to control stimuli. This so-called negative priming effect has been traditionally investigated in the area of selective attention. More recent theory developments conceptualize the negative priming effect as a memory phenomenon. This review presents four models to explain the phenomenon as well as their essential empirical evidence. The review also considers several negative priming characteristics - that is stimulus modality, prime selection and prime response requirement, probe interference, stimulus repetition, aging and thought disorders, and physiological correlates. On these bases, it is concluded that only the distractor inhibition and the episodic retrieval models have survived empirical testing so far. Whereas evidence has increased that negative priming clearly obeys memory retrieval principles, the distractor inhibition model has lost much of its persuasiveness within recent years.
Measuring Source Memory
Authors: Bröder Arndt , Meiser Thorsten
Published: July 2007

Abstract. The investigation of source monitoring (SM) as a special faculty of episodic memory has gained much attention in recent years. However, several measures of source memory have been used in research practice that show empirical and theoretical shortcomings: First, they often confound various cognitive processes like source memory, item memory and response bias, and second, they do not do justice to the multitude of processes involved in SM according to the framework of Johnson, Hashtroudi, and Lindsay (1993) . We therefore review model-based measurement approaches, focusing on multinomial models, and we distinguish between theorizing about source memory and the pragmatics of source memory measurement as two partly separate goals of research. Whereas signal detection models seem to be more adequate theories of the underlying source monitoring process, multinomial models have some pragmatic advantages that nevertheless recommend them as viable measurement tools.
On the Separability of Cognitive Abilities Related to Posner's Attention Components
Authors: Goldhammer Frank , Moosbrugger Helfried , Schweizer Karl
Published: July 2007

Abstract. The study investigates whether five often postulated attention abilities related to Posner's attention components ( Posner & Boies, 1971 ; Posner & Rafal, 1987 ) - alertness, spatial attention, focused attention, attentional switching, and divided attention - represent empirically distinguishable cognitive mechanisms from an individual differences perspective, and to what extent these abilities contribute to conceptually distinct attention abilities related to working memory ( Baddeley, 1986 ), action theory ( Neumann, 1992 ), and psychometric assessment (e.g., Brickenkamp, 1994 ; Moosbrugger & Goldhammer, 2007 ). A total of 232 participants completed 12 attention tasks intended to measure the abilities of interest. First, confirmatory factor analyses (CFA) revealed that the five attention abilities based on Posner's work are moderately related, but clearly distinguishable. The proposed confirmatory factor model consists of one common and five specific attention ability factors. Second, structural equation modeling (SEM) indicated that these five specific attention abilities contribute differentially to attention abilities associated with working memory, action theory, and psychometric assessment, whereas the common factor contributes significantly to all of them. Especially, the results suggest that both divided attention and attentional switching are involved in action-oriented attention abilities as well as in attention abilities associated with psychometric assessment (“concentration”).
A Structural Model of Acculturation and Well-Being Among Immigrants from the Former USSR in Finland
Authors: Jasinskaja-Lahti Inga , Liebkind Karmela
Published: July 2007

Abstract. In this study we tested an integrated model of the relationship between immigrants' linguistic acculturation, socioeconomic status (SES), perceived discrimination, social support networks, general health status, and psychological well-being. A nationwide adult probability sample (N = 2360) included Finnish repatriates and Russian and Estonian immigrants from the former Soviet Union, Russia, and Estonia. In the total sample, linguistic acculturation was directly and negatively related to psychological well-being. Increased acculturation also influenced well-being indirectly through an increase in perceived discrimination. Although acculturation also increased the use of ethnic and host support networks, the effect of these social support networks on well-being depended on the stress level. Particularly, the direct effect of acculturation on well-being disappeared and was instead mediated by social support networks when examining the more vulnerable subsamples of the study, i.e., women and those who perceived substantial discrimination. Higher levels of SES were linked to better well-being through increased health status. It was concluded that the acculturation process plays a dual role in psychological functioning and that it is important to ensure more directly not only immigrants' cultural but also their socioeconomic integration.
A Head-to-Head Comparison of Big-Five Types and Traits in the Prediction of Social Attitudes
Authors: Roth Marcus , von Collani Gernot
Published: July 2007

Abstract. Based on the recent findings that show evidence in favor of five rather than three prototypes in Big Five questionnaire data, the main aim of this study was to evaluate a five-cluster solution. The cluster solution is compared with a Big Five variable-centered approach regarding their relative utility in the concurrent prediction of social attitudes in an adult, nonstudent sample. In addition to the Big Five personality variables, we also assessed social attitudes (generalized prejudice, right-wing authoritarianism, social dominance orientation) and resiliency. Performing head-to-head comparisons to evaluate the goodness of cluster-solutions, our study again provides strong evidence that the five-cluster solution is superior to the three-cluster solution. The results also suggest that in fair comparisons (e.g., dichotomized Big Five scores) the typological approach can compete with the dimensional approach in predicting criterion variables. Furthermore, we have been able to show that the typological approach based on Big Five personality variables can lead to reasonable predictions and new insights with respect to social attitudes and ideological belief systems.
Sex Differences in Childhood Associations between DNA Markers and General Cognitive Ability
Authors: Arden Rosalind , Harlaar Nicole , Plomin Robert
Published: July 2007

Abstract. An association between intelligence at age 7 and a set of five single-nucleotide polymorphisms (SNPs) has been identified and replicated. We used this composite SNP set to investigate whether the associations differ between boys and girls for general cognitive ability at ages 2, 3, 4, 7, 9, and 10 years. In a longitudinal community sample of British twins aged 2-10 (n > 4,000 individuals), we found that the SNP set is more strongly associated with intelligence in males than in females at ages 7, 9, and 10 and the difference is significant at 10. If this finding replicates in other studies, these results will constitute the first evidence of the same autosomal genes acting differently on intelligence in the two sexes.
Individual Differences in Auditory, Pain, and Motor Stimulation
Authors: Schwerdtfeger Andreas
Published: July 2007

Abstract. Augmenting/reducing is a personality dimension related to the processing of sensory stimuli. Augmenters are assumed to augment the impact of stimuli leading to stimulation-avoidant behavior and lower pain tolerance. Reducers are assumed to attenuate sensory stimuli leading to stimulation-seeking behavior and higher pain tolerance. Augmenting/reducing can be assessed by the method of evoked potentials or - as in this study - by questionnaire. Two studies were conducted to examine associations between augmenting/reducing as assessed by questionnaire and stimulus intensity modulation. Study 1 found reducers (n = 24, 12 females) to more frequently consume psychoactive substances and to turn music on louder than augmenters (n = 25, 12 females) even after controlling for individual hearing ability. In Study 2, reducers (n = 19, 10 females) were more pain tolerant than augmenters (n = 18, 9 females) and this difference increased with increasing stimulation time. Moreover, reducers were faster than augmenters in a rapid tapping task but there was no difference in a lower-stimulation tracking task. The results suggest that differences between augmenters and reducers are most reliable when the stimulation potential is high. The clinical relevance of this construct is discussed.
Ion thermalization and wave excitation downstream of Earth's bow shock: A theory for Cluster observations of He2+ acceleration
Authors: Liu Yong C.‐M. , Lee Martin A. , Kucharek Harald , Miao Bin
Published: July 2007

It has been well documented that the plasma immediately downstream of Earth's quasi‐perpendicular bow shock, which consists of reflected protons and directly transmitted ions with large temperature anisotropies (T⊥/Tz), is unstable to the excitation of ion cyclotron waves. These waves in turn scatter the protons and ions to marginal stability. Using Cluster data following the inbound shock crossing at 1717:48 UT on 31 March 2001, we investigate the joint evolution of the proton and helium distribution functions. Within a short distance downstream of the shock the perpendicular heating of helium is faster than the parallel heating, so that the temperature anisotropy of helium first increases near the shock before decreasing farther downstream. The observed spectra of magnetic fluctuations, which are dominated by left‐hand circularly polarized waves, display one peak at < gα (He2+ gyrofrequency), just downstream of the shock, and two peaks with a slot near ≈ gα, farther downstream, where is wave frequency in hertz. We present a quasi‐linear theory that accounts for the observed long‐time decrease of the He2+ temperature anisotropy and the excited wave spectrum. The predicted temperature anisotropy and the general shape of the excited wave spectrum match the observations remarkably well. Nevertheless, certain features of the observations, such as the large amplitude of the lower‐frequency peak and very low amplitude of the higher‐frequency peak just downstream of the shock, require further work.
Fracture mapping in the Soultz‐sous‐Forêts geothermal field using microearthquake locations
Authors: Michelet Sophie , Toksöz M. Nafi
Published: July 2007

In 2003, a massive hydraulic fracturing experiment was carried out at the European Geothermal Hot Dry Rock site at Soultz‐sous‐Forêts, France. The 2 week injection of water generated a high level of microseismic activity, triggering about 90,000 microearthquakes during and after the fluid injection. Of these, 21,000 events, detected at all stations, were located individually with a grid search algorithm to characterize the extent of the seismic zones and ultimately of the fracture network. The accuracy of these initial locations was around 70 m, not sufficient to map detailed fracture patterns. A precise relocation effort was undertaken to reduce the location uncertainties using three different techniques: joint hypocenter determination (JHD), collapsing and multiplet analysis. The collapsing method was added to the JHD results to further consolidate the hypocenters. On the other hand, a multiplet analysis was performed on the initial data set for identifying microearthquakes with similar waveforms and hence relocating relatively the correlated events. The delays in traveltime were computed by wavelet analysis and the events were relocated using a grid search algorithm. We found 7463 events whose seismograms correlated with a correlation coefficient of 0.8 or higher, most of which were doublets. Multiplets are horizontal tube‐like structures with lengths from a hundred to several hundred meters striking along the direction of the maximum compressive horizontal stress. We interpret these structures as the preferential paths where fluid flow is largely confined. This hypothesis is reinforced by the good correlation in depth between the events and the fluid outflows observed in the well. Therefore we believe that these relocated events highlight the zones where the permeability of the reservoir is increased.