WorldWideScience

Sample records for attractive steric interactions

  1. Attractive steric interactions

    CERN Document Server

    Augustus, A S

    1999-01-01

    and (iii), and both the X and Z groups as in (ii), lie on the same side of the ring plane and a 180 deg rotation about a Ar-CH sub 2 X or Ar-CH sub 2 Z bond should give the anti form. In each of these compounds we were able to slow down rotation about both bonds on the NMR time scale and determine whether or not the more compact syn form is the more populated and therefore more stable relative to the anti. The barrier to rotation about the Ar-CH sub 2 X and Ar-CH sub 2 Z bonds is also discussed. In majority of the compounds, with the exception of a few such as the 1-(halomethyl)-3-neopentyl-2,4,5,6-tetramethylbenzenes and the 1,4-disubstituted-2,3,5,6-tetramethylbenzenes, dynamic NMR spectroscopy show that the more compact syn conformations is more stable relative to the anti. The best results were obtained for the 1-neopentyl-2,4,5,6-tetramethylbenzenes left brace type (ii)right brace, where X = tert-butyl and Z = alpha-naphthyl, beta-naphthyl or phenyl. In each of the three compounds, molecular mechanic cal...

  2. Coarse-grained modeling of protein second osmotic virial coefficients: sterics and short-ranged attractions.

    Science.gov (United States)

    Grünberger, Alexander; Lai, Pin-Kuang; Blanco, Marco A; Roberts, Christopher J

    2013-01-24

    A series of coarse-grained models, with different levels of structural resolution, were tested to calculate the steric contributions to protein osmotic second virial coefficients (B(22,S)) for proteins ranging from small single-domain molecules to large multidomain molecules, using the recently developed Mayer sampling method. B(22,S) was compared for different levels of coarse-graining: four-beads-per-amino-acid (4bAA), one-bead-per-amino-acid (1bAA), one-sphere-per-domain (1sD), and one-sphere-per-protein (1sP). Values for the 1bAA and 4bAA models were quantitatively indistinguishable for both spherical and nonspherical proteins, and the agreement with values from all-atom models improved with increasing protein size, making the CG approach attractive for large proteins of biotechnological interest. Interestingly, in the absence of detailed structural information, the hydrodynamic radius (R(h)) along with a simple 1sP approximation provided reasonably accurate values for B(22,S) for both globular and highly asymmetric protein structures, while other 1sP approximations gave poorer agreement; this helps to justify the currently empirical practice of estimating B(22,S) from R(h) for large proteins such as antibodies. The results also indicate that either 1bAA or 4bAA CG models may be good starting points for incorporating short-range attractions. Comparison of gD-crystallin B(22) values including both sterics and short-range attractions shows that 1bAA and 4bAA models give equivalent results when properly scaled to account for differences in the number of surface beads in the two CG descriptions. This provides a basis for future work that will also incorporate long-ranged electrostatic attractions and repulsions. PMID:23245189

  3. Perceived Attractiveness and Classroom Interactions

    Science.gov (United States)

    Algozzine, Bob

    1977-01-01

    Adams and Cohen (1974) demonstrated that facial attractiveness was a salient factor in differential student-teacher interactions. This research investigates further the interaction between teachers and children perceived to be attractive or unattractive by those teachers. It was hypothesized that attractive children would exhibit more "positive,"…

  4. Interactions of triazine herbicides with biochar: Steric and electronic effects.

    Science.gov (United States)

    Xiao, Feng; Pignatello, Joseph J

    2015-09-01

    We studied the adsorption of triazine herbicides and several reference heteroaromatic amines from water onto a temperature series of hardwood biochars (300-700 °C, labeled B300-B700). Adsorption on biochars correlated poorly with pyrolysis temperature, H/C, O/C, mean minimum fused ring size, surface area (N2 or CO2), microporosity, and mesoporosity, but correlated well with a weighted sum of microporosity and mesoporosity. Steric effects were evident by the negative influence of solute molecular volume on adsorption rate. For a given compound, adsorption rate maximized for the biochar with the greatest mesoporosity-to-total-porosity ratio, suggesting that mesopores are important for facilitating diffusion into pore networks. The cationic forms of amines adsorb more slowly than the neutral forms. To further probe steric and electronic effects, adsorption on a biochar (B400) was compared to adsorption on graphite-a nonporous reference material with an unhindered, unfunctionalized graphene surface-and in comparison with reference compounds (benzene, naphthalene, pyridine, quinoline and 1,3-triazine). Relative to benzene, the surface area-normalized adsorption of the triazine herbicides was disfavored on B400 (favored on graphite) by 11-19 kJ/mol, depending on concentration. It is estimated that steric suppression of B400 adsorption comprises 6.2 kJ/mol of this difference, the remainder being the difference in polar electronic effects. Based on the behavior of the reference amines, the difference in polar effects is dominated by π-π electron donor-acceptor (EDA) interactions with sites on polyaromatic surfaces, which are more electropositive and/or more abundant on graphite. Overall, our results show that mesoporosity is critical, that adsorption rate is a function of solute molecular size and charge, that steric bulk in the solute suppresses equilibrium adsorption, and that π-π EDA forces play a role in triazine polar interactions with biochar. PMID:26001283

  5. Generalized Poisson-Boltzmann Equation Taking into Account Ionic Interaction and Steric Effects

    Institute of Scientific and Technical Information of China (English)

    刘新敏; 李航; 李睿; 田锐; 许晨阳

    2012-01-01

    Generalized Poisson l3oltzmann equation which takes into account both ionic interaction in bulk solution and steric effects of adsorbed ions has been suggested. We found that, for inorganic cations adsorption on negatively charged surface, the steric effect is not significant for surface charge density 〈 0.0032 C/dm2, while the ionic interaction is an important effect for electrolyte concentration 〉 0.15 tool/1 in bulk solution. We conclude that for most actual cases the original PB equation can give reliable result in describing inorganic cation adsorption.

  6. Modeling multivalent ligand-receptor interactions with steric constraints on configurations of cell surface receptor aggregates

    Energy Technology Data Exchange (ETDEWEB)

    Monine, Michael [Los Alamos National Laboratory; Posner, Richard [TRANSLATION GENOMICS RESAEARCH INSTITUTE; Savage, Paul [BYU; Faeder, James [UNIV OF PITTSBURGH; Hlavacek, William S [UNM

    2008-01-01

    Signal transduction generally involves multivalent protein-protein interactions, which can produce various protein complexes and post-translational modifications. The reaction networks that characterize these interactions tend to be so large as to challenge conventional simulation procedures. To address this challenge, a kinetic Monte Carlo (KMC) method has been developed that can take advantage of a model specification in terms of reaction rules for molecular interactions. A set of rules implicitly defines the reactions that can occur as a result of the interactions represented by the rules. With the rule-based KMC method, explicit generation of the underlying chemical reaction network implied by rules is avoided. Here, we apply and extend this method to characterize the interactions of a trivalent ligand with a bivalent cell-surface receptor. This system is also studied experimentally. We consider the following kinetic models: an equivalent-site model, an extension of this model, which takes into account steric constraints on the configurations of receptor aggregates, and finally, a model that accounts for cyclic receptor aggregates. Simulation results for the equivalent-site model are consistent with an equilibrium continuum model. Using these models, we investigate the effects of steric constraints and the formation of cyclic aggregates on the kinetics and equilibria of small and large aggregate formation and the percolation phase transition that occurs in this system.

  7. Attracting pedestrians’ attention using interaction technology

    OpenAIRE

    Mellquist, Michael

    2016-01-01

    The technology and marketing channels to display and broadcast advertisements are ever changing; this has led to the change of many forms of advertisements. Public advertisements have not changed as drastically as many others and can therefore be seen as out-dated. In this paper a prototype of an interactive advertisement with a dynamic user flow is presented where focus has been on attracting attention. Different interaction technologies have been discussed and compared. A Kinect sensor has ...

  8. Making interactive personal guides more attractive

    OpenAIRE

    Nijholt, A.; Cappellini, V.; Hemsley, J.; Stanke, G.

    2003-01-01

    We investigate the different roads that should be taken to make 2D and 3D guides on webpages and in (augmented) virtual reality environments more attractive. Currently, most of the approaches have been done from a graphics point of view. Often research stops when we have to model how these graphically well-designed agents are going to do something useful and have to interact with the user or a visitor of an environment. What does the virtual guide know about the environment, what are its goal...

  9. Attractions in sterically stabilized silica dispersions : III. Second virial coefficient as a function of temperature, as measured by means of turbidity

    NARCIS (Netherlands)

    Jansen, J.W.; Kruif, C.G. de; Vrij, A.

    1986-01-01

    Silica particles coated with octadecyl chains and dispersed in toluene exhibit attractions on lowering the temperature. The attraction is supposed to be the result of interactions between the chain segments and solvent. Since light is strongly scattered in the dispersions turbidity measurements are

  10. Making interactive personal guides more attractive

    NARCIS (Netherlands)

    Nijholt, A.; Cappellini, V.; Hemsley, J.; Stanke, G.

    2003-01-01

    We investigate the different roads that should be taken to make 2D and 3D guides on webpages and in (augmented) virtual reality environments more attractive. Currently, most of the approaches have been done from a graphics point of view. Often research stops when we have to model how these graphical

  11. Weak interactions strongly attracting Nobel prizes

    International Nuclear Information System (INIS)

    The discovery is discussed of intermediate bosons W and Z at CERN. The idea behind the experiment is explained. Chronologically, the history is shown of the development of the weak interaction theory up to the Glashow-Salam-Weinberg model unifying weak and electromagnetic interactions into electroweak interactions. Some open problems of subnuclear physics are also discussed. (Z.J.)

  12. The interaction of sterically stabilized magnetic nanoparticles with fresh human red blood cells

    Directory of Open Access Journals (Sweden)

    Pham BTT

    2015-10-01

    Full Text Available Binh TT Pham,1 Nirmesh Jain,1 Philip W Kuchel,2 Bogdan E Chapman,2,† Stephanie A Bickley,3 Stephen K Jones,3 Brian S Hawkett11School of Chemistry, University of Sydney, 2School of Molecular Bioscience, University of Sydney, 3Sirtex Medical Limited, Sydney, NSW, Australia†Bogdan E Chapman passed away on August 16, 2014Abstract: Sterically stabilized superparamagnetic iron oxide nanoparticles (SPIONs were incubated with fresh human erythrocytes (red blood cells [RBCs] to explore their potential application as magnetic resonance imaging contrast agents. The chemical shift and linewidth of 133Cs+ resonances from inside and outside the RBCs in 133Cs nuclear magnetic resonance spectra were monitored as a function of time. Thus, we investigated whether SPIONs of two different core sizes and with three different types of polymeric stabilizers entered metabolically active RBCs, consuming glucose at 37°C. The SPIONs broadened the extracellular 133Cs+ nuclear magnetic resonance, and brought about a small change in its chemical shift to a higher frequency; while the intracellular resonance remained unchanged in both amplitude and chemical shift. This situation pertained over incubation times of up to 90 minutes. If the SPIONs had entered the RBCs, the intracellular resonance would have become broader and possibly even shifted. Therefore, we concluded that our SPIONs did not enter the RBCs. In addition, the T2 relaxivity of the small and large particles was 368 and 953 mM-1 s-1, respectively (three and nine times that of the most effective commercially available samples. This suggests that these new SPIONs will provide a superior performance to any others reported thus far as magnetic resonance imaging contrast agents.Keywords: 133Cs NMR spectroscopy, bulk magnetic susceptibility, fresh human erythrocyte, particle stability, paramagnetic shift, superparamagnetic iron oxide nanoparticles, SPIONs

  13. Attractive Coulomb interaction of two-dimensional Rydberg excitons

    Science.gov (United States)

    Shahnazaryan, V.; Shelykh, I. A.; Kyriienko, O.

    2016-06-01

    We analyze theoretically the Coulomb scattering processes of highly excited excitons in the direct-band-gap semiconductor quantum wells. We find that contrary to the interaction of ground-state excitons, the electron and hole exchange interaction between excited excitons has an attractive character both for s - and p -type two-dimensional (2D) excitons. Moreover, we show that similar to the three-dimensional highly excited excitons, the direct interaction of 2D Rydberg excitons exhibits van der Waals-type long-range interaction. The results predict the linear growth of the absolute value of exchange interaction strength with an exciton principal quantum number and point the way towards enhancement of optical nonlinearity in 2D excitonic systems.

  14. The Law of Attraction in Human-Robot Interaction

    Directory of Open Access Journals (Sweden)

    Eunil Park

    2012-07-01

    Full Text Available Following the law of attraction in human‐human interaction, this paper examines the effects of a robot’s personality and a human’s personality in various human‐robot interactions. This study was conducted using robots that were programmed to mimic both extroverted and introverted personality types, as well as humans who were classified as having introverted, extroverted or intermediate personality types. Using a 3 x 2 between‐ subjects experiment with 120 participants, the results indicated that participants who interacted with a similar personality robot were more comfortable than those who engaged with a different personality robot. Yet, the evaluation of social presence presented an opposing result. Both the implications and limitations of the present study, as well as guidelines for future research, are discussed.

  15. Hydrodynamic interactions of sheets vs filaments: Synchronization, attraction, and alignment

    Science.gov (United States)

    Olson, Sarah D.; Fauci, Lisa J.

    2015-12-01

    The synchronization of nearby sperm flagella as they swim in a viscous fluid was observed nearly a century ago. In the early 1950s, in an effort to shed light on this intriguing phenomenon, Taylor initiated the mathematical analysis of the fluid dynamics of microorganism motility. Since then, models have investigated sperm hydrodynamics where the flagellum is treated as a waving sheet (2D) or as a slender waving filament (3D). Here, we study the interactions of two finite length, flexible filaments confined to a plane in a 3D fluid and compare these to the interactions of the analogous pair of finite, flexible sheets in a 2D fluid. Within our computational framework using regularized Stokeslets, this comparison is easily achieved by choosing either the 2D or 3D regularized kernel to compute fluid velocities induced by the actuated structures. We find, as expected, that two flagella swimming with a symmetric beatform will synchronize (phase-lock) on a fast time scale and attract towards each other on a longer time scale in both 2D and 3D. For a symmetric beatform, synchronization occurs faster in 2D than 3D for sufficiently stiff swimmers. In 3D, a greater enhancement in efficiency and swimming velocity is observed for attracted swimmers relative to the 2D case. We also demonstrate the tendency of two asymmetrically beating filaments in a 3D fluid to align — in tandem — exhibiting an efficiency boost for the duration of their sustained alignment.

  16. Attraction or Repulsion? London Dispersion Forces Control Azobenzene Switches.

    Science.gov (United States)

    Schweighauser, Luca; Strauss, Marcel A; Bellotto, Silvia; Wegner, Hermann A

    2015-11-01

    Large substituents are commonly seen as entirely repulsive through steric hindrance. Such groups have additional attractive effects arising from weak London dispersion forces between the neutral atoms. Steric interactions are recognized to have a strong influence on isomerization processes, such as in azobenzene-based molecular switches. Textbooks indicate that steric hindrance destabilizes the Z isomers. Herein, we demonstrate that increasing the bulkiness of electronically equal substituents in the meta-position decreases the thermal reaction rates from the Z to the E isomers. DFT computations revealed that attractive dispersion forces essentially lower the energy of the Z isomers. PMID:26350759

  17. Modeling Flocks and Prices: Jumping Particles with an Attractive Interaction

    CERN Document Server

    Balazs, Marton; Toth, Balint

    2011-01-01

    We introduce and investigate a new model of a finite number of particles jumping forward on the real line. The jump lengths are independent of everything, but the jump rate of each particle depends on the relative position of the particle compared to the center of mass of the system. The rates are higher for those left behind, and lower for those ahead of the center of mass, providing an attractive interaction keeping the particles together. We prove that in the fluid limit, as the number of particles goes to infinity, the evolution of the system is described by a mean field equation that exhibits traveling wave solutions. A connection to extreme value statistics is also provided.

  18. Molecular theory for the effects of solute attractive forces on hydrophobic interactions

    CERN Document Server

    Chaudhari, M I; Asthagiri, D; Tan, L; Pratt, L R

    2015-01-01

    We consider the local molecular field (LMF) theory for the effects of solute attractive forces on hydrophobic interactions. The principal result of LMF theory is outlined, then tested by obtaining radial distribution functions (rdfs) for Ar atoms in water, with and without attractive interactions distinguished by the Weeks-Chandler-Andersen (WCA) separation. Change from purely repulsive atomic solute interactions to include realistic attractive interactions substantially \\emph{diminishes} the strength of hydrophobic bonds. Since attractions make a big contribution to hydrophobic interactions, Pratt-Chandler theory, which did not include attractions, should not be simply comparable to computer simulation results with general physical interactions, including attractions. The rdfs permit evaluation of osmotic second virial coefficients $B_2$. Those $B_2$ are consistent with the conclusion that incorporation of attractive interactions leads to more positive (repulsive) values. In all cases here, $B_2$ becomes mor...

  19. A Model for Macroscopic Quantum Tunneling of Bose-Einstein Condensate with Attractive Interaction

    Institute of Scientific and Technical Information of China (English)

    YAN Ke-Zhu; TAN Wei-Han

    2000-01-01

    Based on the numerical wave function solutions of neutral atoms with attractive interaction in a harmonic trap, we propose an exactly solvable model for macroscopic quantum tunneling of a Bose condensate with attractive interaction. We calculate the rate of macroscopic quantum tunneling from a metastable condensate state to the collapse state and analyze the stability of the attractive Bose-Einstein condensation.

  20. Measurable consequences of an attractive anti KN interaction

    Energy Technology Data Exchange (ETDEWEB)

    Epple, Eliane Melanie Franziska

    2014-07-07

    In the field of low energy QCD the effective description of interactions between ground state hadrons plays a major role in nuclear physics. One of these interactions occurs between anti-kaons and nucleons, and is a topic of a long standing interest. A specific attention is lately drawn to the possible existence of bound states between anti Ks and nucleons. This old concept is based on the idea that the attractive interaction between anti-kaons and nucleons, that already manifests itself as the anti KN-pole of the Λ(1405)-resonance, is strong enough to bind further nucleons by the help of a anti K. The simplest form of these clusters is the anti KNN which consists of a anti K bound to two nucleons. This state might decay into pΛ and is, thus, accessible via open strangeness production in p+p collisions. This work continues the investigations in this field, as a rather puzzling impression is left behind from previous experiments, and further conclusions are needed. The work contains two major data analyses. The first one is dedicated to the anti KN bound state, and selects the semi-exclusive reaction p+p→p+K{sup +}+Λ+X. This was done to investigate the strange resonances Λ(1405) and Σ(1385){sup 0} in their neutral decay channels Σ{sup 0}π{sup 0} and Λπ{sup 0}, respectively. Besides resonance production, several other states contribute to this final state. Their relative strengths have been determined and the obtained production cross sections were in agreement with the results from an independent analysis of the Λ(1405) decay into Σ{sup ±}π{sup -+}, done in a parallel work. To set reasonable constraints for coupled channels calculations in the anti KN sector, a high-precision Λ(1405)-mass spectrum is needed. The obtained yield and uncertainty of the Λ(1405) contribution to the final spectra, however, showed that the required precision is not given in the neutral decay channel. Nonetheless, the extracted production cross section of the Σ(1385){sup 0

  1. Measurable consequences of an attractive anti KN interaction

    International Nuclear Information System (INIS)

    In the field of low energy QCD the effective description of interactions between ground state hadrons plays a major role in nuclear physics. One of these interactions occurs between anti-kaons and nucleons, and is a topic of a long standing interest. A specific attention is lately drawn to the possible existence of bound states between anti Ks and nucleons. This old concept is based on the idea that the attractive interaction between anti-kaons and nucleons, that already manifests itself as the anti KN-pole of the Λ(1405)-resonance, is strong enough to bind further nucleons by the help of a anti K. The simplest form of these clusters is the anti KNN which consists of a anti K bound to two nucleons. This state might decay into pΛ and is, thus, accessible via open strangeness production in p+p collisions. This work continues the investigations in this field, as a rather puzzling impression is left behind from previous experiments, and further conclusions are needed. The work contains two major data analyses. The first one is dedicated to the anti KN bound state, and selects the semi-exclusive reaction p+p→p+K++Λ+X. This was done to investigate the strange resonances Λ(1405) and Σ(1385)0 in their neutral decay channels Σ0π0 and Λπ0, respectively. Besides resonance production, several other states contribute to this final state. Their relative strengths have been determined and the obtained production cross sections were in agreement with the results from an independent analysis of the Λ(1405) decay into Σ±π-+, done in a parallel work. To set reasonable constraints for coupled channels calculations in the anti KN sector, a high-precision Λ(1405)-mass spectrum is needed. The obtained yield and uncertainty of the Λ(1405) contribution to the final spectra, however, showed that the required precision is not given in the neutral decay channel. Nonetheless, the extracted production cross section of the Σ(1385)0-resonance provided a crucial constraint for

  2. Rotational states of Bose gases with attractive interactions in anharmonic traps

    International Nuclear Information System (INIS)

    A rotated and harmonically trapped Bose gas with attractive interactions is expected to either remain stationary or escape from the trap. Here we report that, on the contrary, in an anharmonic trapping potential the Bose gas with attractive interactions responds to external rotation very differently, namely, through center-of-mass motion or by formation of vortices

  3. Sterically stabilized colloids with tunable repulsions.

    Science.gov (United States)

    van Gruijthuijsen, Kitty; Obiols-Rabasa, Marc; Heinen, Marco; Nägele, Gerhard; Stradner, Anna

    2013-09-10

    When studying tunable electrostatic repulsions in aqueous suspensions of charged colloids, irreversible colloid aggregation or gelation may occur at high salt concentrations. For many commonly used synthetic colloids, such as polystyrene and silica particles, the reason for coagulation is the presence of unbalanced, strongly attractive, and short-ranged van der Waals (VDW) forces. Here, we present an aqueous polystyrene model colloid that is sterically stabilized against VDW attractions. We show that the synthesis procedure, based on a neutral initiator couple and a nonionic surfactant, introduces surface charges that can be further increased by the addition of charged comonomer methacrylic acid. Thus, the interactions between the polystyrene spheres can be conveniently tuned from hard-sphere-like to charge-stabilized with long-ranged electrostatic repulsions described by a Yukawa-type pair potential. The particle size, grafting density, core-shell structure, and surface charge are characterized by light and neutron scattering. Using X-ray and neutron scattering in combination with an accurate analytic integral equation scheme for the colloidal static structure factor, we deduce effective particle charges for colloid volume fractions ≥0.1 and salt concentrations in the range of 1.5 to 50 mM. PMID:23937718

  4. Functional Integral Approach to the Transition Temperature of Attractive Interacting Bose Gas in Traps

    Institute of Scientific and Technical Information of China (English)

    HU Guang-Xi; DAI Xian-Xi

    2004-01-01

    The functional integral approach (FIA) is introduced to study the transition temperature of an imperfect Bose gas in traps.An interacting model in quantum statistical mechanics is presented.With the model we study a Bose gas with attractive interaction trapped in an external potential.We obtain the result that the transition temperature of a trapped Bose gas will slightly shift upwards owing to the attractive interacting force.Successful application of the FIA to Bose systems is demonstrated.

  5. Facial and Full-Length Ratings of Attractiveness Related to the Social Interactions of Young Children.

    Science.gov (United States)

    Smith, Gregory J.

    1985-01-01

    Aggressive and prosocial peer interactions were observed in 38 preschool-age children. Attractive girls received more prosocial and fewer aggressive advances than unattractive girls. There was no differential treatment of boys related to attractiveness. Results are discussed in relationship to possible developmental implications and their parallel…

  6. Physical Attractiveness: Interactive Effects of Counselor and Client on Counseling Processes.

    Science.gov (United States)

    Vargas, Alice M.; Borkowski, John G.

    1983-01-01

    Assessed how the physical attractiveness of counselors and clients interacted to build rapport in two experiments involving college students (N=128 and N=64). Results showed the counselor's physical attractiveness had a major impact on her perceived effectiveness and the client's expectation of success irrespective of the client's attractiveness…

  7. Interaction parameter (c); expansion factor (e); steric hindrance factor (s); and shielding function F(x); for the system PEA-organic solvents by intrinsic viscosity measurements

    International Nuclear Information System (INIS)

    In this work we present experimental data of the Flory binary interaction parameter, χ, of poly (ethylene adipate) PEA, a plasticizer material. We have used the viscometric method for measuring dilute PEA solutions in good solvents: benzene, chloroform and acetone. A procedure based on the Stockmayer-Fixman, (SF), hydrodynamic solutions theory, allows us to evaluate some thermodynamic parameters via the intrinsic viscosity [η], measured in several good solvents. This method also estimates the unperturbed parameter, kθ, and the steric hindrance parameter, (σ), by viscosity measurements at constant temperature of 30 deg C. By correlation of the molecular weight (M) and intrinsic viscosity data, according to the Stockmayer-Fixman (SF) solution theory model, values of Flory binary interaction parameter χ, equal to χ1,2 =0.1544 ±0.01; χ1,2 =0.1631 ±0.01; and χ1,2 =0.1922 ± 0.01, for PEA in benzene, chloroform and acetone, respectively, were obtained. In addition we applied the Debye-Bueche theory, in order to estimate values of: expansion factor (ε), shielding factor (ξ) and depth of shielding (L) for the system PEA-organic solvents, by [η] and (M) experimental data correlation. The results confirm that values obtained, correspond to 'good solvents' for the PEA polymer. (author)

  8. Attractive interaction between an atom and a surface

    International Nuclear Information System (INIS)

    Using a general self-energy formalism we examine the interaction between an atom and a surface. Considered in detail are deviations from the Van der Waals force due to recoil and finite velocity of the particle. Calculations for positronium near a metal surface show that for such systems recoil and velocity effects are significant even at very low energies. We also examine the mechanisms for energy exchange with the surface and calculations show that single quantum events do not always dominate the exchange rates. 8 references, 2 figures

  9. Intergroup Cooperation and Intergroup Attraction: The Effect of Previous Interaction and Outcome of Combined Effort

    Science.gov (United States)

    Worchel, Stephen; And Others

    1977-01-01

    Tests the hypothesis that the effect of intergroup cooperation on intergroup attraction would depend on both the outcome of the cooperation and the nature of the past interaction between groups. (Author/RK)

  10. Attractive and repulsive interactions between and within adsorbed ribonuclease A layers.

    OpenAIRE

    Belfort, G; Lee, C S

    1991-01-01

    Adsorbed layers of pancreatic RNase A on molecularly smooth mica in aqueous solution attract inorganic mica surfaces whereas they repel similarly adsorbed RNase A layers. As the clean mica surface is covered with RNase A, the attractive interaction slowly diminishes with time and eventually converts to a purely repulsive interaction. Solvent is squeezed out of the solution in the gap during compression of the two surfaces so that the adsorbed protein concentration, as measured directly by the...

  11. Collapse of a self-gravitating Bose-Einstein condensate with attractive self-interaction

    OpenAIRE

    Chavanis, Pierre-Henri

    2016-01-01

    We study the collapse of a self-gravitating Bose-Einstein condensate with attractive self-interaction. Equilibrium states in which the gravitational attraction and the attraction due to the self-interaction are counterbalanced by the quantum pressure exist only below a maximum mass $M_{\\rm max}=1.012\\hbar/\\sqrt{Gm|a_s|}$ where $a_sM_{\\rm max}$ the system is expected to collapse and form a black hole. We study the collapse dynamics by making a Gaussian ansatz for the wave function. We find tha...

  12. Adjusting the DNA Interaction and Anticancer Activity of Pt(II) N-Heterocyclic Carbene Complexes by Steric Shielding of the Trans Leaving Group.

    Science.gov (United States)

    Muenzner, Julienne K; Rehm, Tobias; Biersack, Bernhard; Casini, Angela; de Graaf, Inge A M; Worawutputtapong, Pawida; Noor, Awal; Kempe, Rhett; Brabec, Viktor; Kasparkova, Jana; Schobert, Rainer

    2015-08-13

    Five platinum(II) complexes bearing a (1,3-dibenzyl)imidazol-2-ylidene ligand but different leaving groups trans to it were examined for cytotoxicity, DNA and cell cycle interference, vascular disrupting properties, and nephrotoxicity. The cytotoxicity of complexes 3a-c increased with the steric shielding of their leaving chloride ligand, and complex 3c, featuring two triphenylphosphanes, was the most efficacious, with submicromolar IC50 concentrations. Complexes 3a-c interacted with DNA in electrophoretic mobility shift and ethidium bromide binding assays. The cationic complex 3c did not bind coordinatively to DNA but led to its aggregation, damage that is not amenable to the usual repair mechanisms. Accordingly, it arrested the cell cycle of melanoma cells in G1 phase, whereas cis-dichlorido[(1,3-dibenzyl)imidazol-2-ylidene](dimethyl sulfoxide) platinum(II) 3a induced G2/M phase arrest. Complex 3c also disrupted the blood vessels in the chorioallantoic membrane of fertilized chicken eggs. Ex vivo studies using precision-cut tissue slices suggested the nephrotoxicities of 3a-c to be clinically manageable. PMID:26182125

  13. Bose-Einstein atoms in atomic traps with predominantly attractive two-body interactions

    International Nuclear Information System (INIS)

    Using the Perron-Frobenius theorem, we prove that the results by Wilkin, Gunn, and Smith [Phys. Rev. Lett. 80, 2265 (1998)] for the ground states at angular momentum L of N harmonically trapped Bose atoms, interacting via weak attractive δ2(r) forces, are valid for a broad class of predominantly attractive interactions V(r), not necessarily attractive for any r. This class is described by sufficient conditions on the two-body matrix elements of the potential V(r). It includes, in particular, the Gaussian attraction of arbitrary radius, -1/r-Coulomb and log(r)-Coulomb forces, as well as all the short-range interactions satisfying inequality ∫d2r-vectorV(r)<0. In the precollapse regime, the angular momentum L is concentrated in the collective 'center-of-mass' mode, and there is no condensation at high L

  14. Supramolecular association via Sb...S and C-H...S interactions in dimeric tris(N,N-dimethyldithiocarbamato-S,S')antimony(III): an approach to overcome the concept of steric bulk on such interactions.

    Science.gov (United States)

    Chauhan, H P S; Carpenter, Jaswant

    2013-12-01

    Tris(N,N-dimethyldithiocarbamato-S,S')antimony(III) has been isolated as a dimer in acetonitrile. Single-crystal X-ray analysis shows that the molecule possesses both Sb···S and C-H···S interactions, which results in a supramolecular association in the absence of hydrogen-bonding functionality on the R group. The co-existence in the title compound of such interactions is a unique character of known dimeric antimony(III) alkyl and/or aryl dithiocarbamate complexes. The literature reveals that the species where the alkyl and/or aryl dithiocarbamates carry the following groups: R = methyl (chloroform solvated), ethyl, n-propyl, pyrrolidine, morpholine, piperidine, azepane, benzyl, methylphenyl, are not capable of forming significant hydrogen-bonding interactions. However, either Sb···S or C-H···S intermolecular interactions dominate between two centrosymmetrically related molecules leading to a supramolecular aggregation. In the species where the R group carries hydrogen-bonding functionality, i.e. 2-hydroxylethyl, the C-H···S interactions are subverted by O-H···O hydrogen bonding. In addition, the title compound does not have steric hindrance or any hydrogen-bonding group but is stabilized with the co-existence of Sb···S and C-H···S interactions. Analysis of the secondary interactions of a series of analogues previously reported reveals that steric bulk is unnecessary for the mitigation of Sb···S interactions and for the establishment of C-H···S secondary bonding. PMID:24253087

  15. Molecular theory and the effects of solute attractive forces on hydrophobic interactions

    International Nuclear Information System (INIS)

    The role of solute attractive forces on hydrophobic interactions is studied by coordinated development of theory and simulation results for Ar atoms in water. We present a concise derivation of the local molecular field (LMF) theory for the effects of solute attractive forces on hydrophobic interactions, a derivation that clarifies the close relation of LMF theory to the EXP approximation applied to this problem long ago. The simulation results show that change from purely repulsive atomic solute interactions to include realistic attractive interactions diminishes the strength of hydrophobic bonds. For the Ar-Ar rdfs considered pointwise, the numerical results for the effects of solute attractive forces on hydrophobic interactions are opposite in sign and larger in magnitude than predicted by LMF theory. That comparison is discussed from the point of view of quasichemical theory, and it is suggested that the first reason for this difference is the incomplete evaluation within LMF theory of the hydration energy of the Ar pair. With a recent suggestion for the system-size extrapolation of the required correlation function integrals, the Ar-Ar rdfs permit evaluation of osmotic second virial coefficients B2. Those B2's also show that incorporation of attractive interactions leads to more positive (repulsive) values. With attractive interactions in play, B2 can change from positive to negative values with increasing temperatures. Furthermore, this is consistent with the puzzling suggestions of decades ago that B2 ≈ 0 for intermediate cases of temperature or solute size. In all cases here, B2 becomes more attractive with increasing temperature

  16. Management principles of the interaction between market attractiveness producer and its recipients

    OpenAIRE

    O.V. SVIRIDOVA

    2013-01-01

    The aim of the article. The article is devoted to the definition of the content of interaction between attractiveness producer and its recipients through the prism of general and derived management principles. Actuality of this article is caused by the formation of long-term relationships between business subjects. The main aim of these relationships is attracting and using of resources to further joint production and benefits distribution from these activities. Formation of such long-term re...

  17. Adjusting the DNA Interaction and Anticancer Activity of Pt(II) N-Heterocyclic Carbene Complexes by Steric Shielding of the Trans Leaving Group

    NARCIS (Netherlands)

    Muenzner, Julienne K.; Rehm, Tobias; Biersack, Bernhard; Casini, Angela; de Graaf, Inge A. M.; Worawutputtapong, Pawida; Noor, Awal; Kempe, Rhett; Brabec, Viktor; Kasparkova, Jana; Schobert, Rainer

    2015-01-01

    Five platinum(LI) complexes bearing a (1,3-dibenzyl)imidazol-2-ylidene ligand but different leaving groups trans to it were examined for cytotomicity, DNA and cell cycle interference, vascular disrupting properties, and nephrotoxicity. The cytotoxicity of complexes 3a-c increased with the steric shi

  18. Management principles of the interaction between market attractiveness producer and its recipients

    Directory of Open Access Journals (Sweden)

    O.V. Sviridova

    2013-09-01

    Full Text Available The aim of the article. The article is devoted to the definition of the content of interaction between attractiveness producer and its recipients through the prism of general and derived management principles. Actuality of this article is caused by the formation of long-term relationships between business subjects. The main aim of these relationships is attracting and using of resources to further joint production and benefits distribution from these activities. Formation of such long-term relationships in condition of high competitiveness is one of the urgent problems of modern enterprises. In this regard, the traditional management principles are supplemented by the principles of the interaction and attractiveness managing. The purpose of the article is further improving of management principles through the establishment of specific management principles of the interaction between market attractiveness producer and its recipients.The results of the analysis. Management principles are the statements of fundamental truth based on logic which provides guidelines for managerial decision making and actions. The research of classic, general and structural management principles is conducted in the article. The possibility and necessity of ascertainment of the derivative management principles of interaction between subjects of market environment is noted. Derivative management principles reflect the content of the specialized management activity on forming of enterprise attractiveness. The analysis of existing management principles of different objects is conducted. It is established that as a basis for systematization of management principles scientists use different management features, such as socio-political principles, principles of management culture and state-administrative activity, socio-political, structural, scientific, legal, personnel and organizational basis.Results of research of management principles and management interaction proved

  19. Collapse and coexistence for a molecular braid with an attractive interaction component subject to mechanical forces

    International Nuclear Information System (INIS)

    Dual mechanical braiding experiments provide a useful tool with which to investigate the nature of interactions between rod-like molecules, for instance actin and DNA. In conditions close to molecular condensation, one would expect an appearance of a local minimum in the interaction potential between the two molecules. We investigate this situation, introducing an attractive component into the interaction potential, using a model developed for describing such experiments. We consider both attractive interactions that do not depend on molecular structure and those which depend on a DNA-like helix structure. In braiding experiments, an attractive term may lead to certain effects. A local minimum may cause molecules to collapse from a loosely braided configuration into a tight one, occurring at a critical value of the moment applied about the axis of the braid. For a fixed number of braid pitches, this may lead to coexistence between the two braiding states, tight and loose. Coexistence implies certain proportions of the braid are in each state, their relative size depending on the number of braid pitches. This manifests itself as a linear dependence in numerically calculated quantities as functions of the number of braid pitches. Also, in the collapsed state, the braid radius stays roughly constant. Furthermore, if the attractive interaction is helix dependent, the left-right handed braid symmetry is broken. For a DNA like charge distribution, using the Kornyshev–Leikin interaction model, our results suggest that significant braid collapse and coexistence only occurs for left handed braids. Regardless of the interaction model, the study highlights the possible qualitative physics of braid collapse and coexistence; and the role helix specific forces might play, if important. The model could be used to connect other microscopic theories of interaction with braiding experiments. (paper)

  20. A Monte Carlo study of temperature-programmed desorption spectra with attractive lateral interactions

    CERN Document Server

    Jansen, A P J

    1995-01-01

    We present results of a Monte Carlo study of temperature-programmed desorption in a model system with attractive lateral interactions. It is shown that even for weak interactions there are large shifts of the peak maximum temperatures with initial coverage. The system has a transition temperature below which the desorption has a negative order. An analytical expression for this temperature is derived. The relation between the model and real systems is discussed.

  1. The role of attractive interactions in the dynamics of molecules in liquids

    CERN Document Server

    You, X; Rick, S W

    2014-01-01

    The friction kernel (or memory function) $\\gamma(t)$ characterizing single-molecule dynamics in strongly bound liquids exhibits two distinct relaxations with the longer time-scale relaxation associated with attractive intermolecular forces. This observation identifies differing roles of repulsive and attractive interaction in the motions of molecules in equilibrium liquids, and thus provides a basis for a renewed investigation of a van der Waals picture of the transport properties of liquids. This conclusion is supported by extracting $\\gamma(t)$ from molecular dynamics simulation data for four common molecular liquids.

  2. Collapse of a self-gravitating Bose-Einstein condensate with attractive self-interaction

    CERN Document Server

    Chavanis, Pierre-Henri

    2016-01-01

    We study the collapse of a self-gravitating Bose-Einstein condensate with attractive self-interaction. Equilibrium states in which the gravitational attraction and the attraction due to the self-interaction are counterbalanced by the quantum pressure exist only below a maximum mass $M_{\\rm max}=1.012\\hbar/\\sqrt{Gm|a_s|}$ where $a_sM_{\\rm max}$ the system is expected to collapse and form a black hole. We study the collapse dynamics by making a Gaussian ansatz for the wave function. We find that the collapse time scales as $(M/M_{\\rm max}-1)^{-1/4}$ for $M\\rightarrow M_{\\rm max}^+$ and as $M^{-1/2}$ for $M\\gg M_{\\rm max}$. We apply our results to standard axions with mass $m=10^{-4}\\, {\\rm eV}/c^2$ and scattering length $a_s=-5.8\\times 10^{-53}\\, {\\rm m}$ for which $M_{\\rm max}=6.5\\times 10^{-14}M_{\\odot}$ and $R=3.3\\times 10^{-4}\\, R_{\\odot}$. We confirm our previous claim that bosons with attractive self-interaction, such as standard axions, may form low mass stars but cannot form dark matter halos of relevan...

  3. Attractive Interaction Between Pulses in a Model for Binary-Mixture Convection

    CERN Document Server

    Riecke, H

    1995-01-01

    Recent experiments on convection in binary mixtures have shown that the interaction between localized waves (pulses) can be repulsive as well as {\\it attractive} and depends strongly on the relative {\\it orientation} of the pulses. It is demonstrated that the concentration mode, which is characteristic of the extended Ginzburg-Landau equations introduced recently, allows a natural understanding of that result. Within the standard complex Ginzburg-Landau equation this would not be possible.

  4. Topological States in a One-Dimensional Fermi Gas with Attractive Interactions

    OpenAIRE

    Ruhman, Jonathan; Berg, Erez; Altman, Ehud

    2014-01-01

    We describe a novel topological superfluid state, which forms in a one-dimensional Fermi gas with Rashba-like spin-orbit coupling, a Zeeman field and intrinsic attractive interactions. In spite of total number conservation and the presence of gapless excitations, Majorana-like zero modes appear in this system and can be linked with interfaces between two distinct phases that naturally form at different regions of the harmonic trap. As a result, the low lying collective excitations of the syst...

  5. Concept-Driven Interaction Design Research in the domain of attractive aging: the example of Walky

    DEFF Research Database (Denmark)

    Nazzi, Elena; Bagalkot, Naveen L.; Nagargoje, Arun;

    2012-01-01

    In this paper we answer the call for “designing for an attractive ageing” by designing for social interaction of senior citizens within their local community. In this vein, we present Walky, a design exploration through which we explored if, and how, augmenting the rollator that senior citizens u...... providing the example of Walky and its compositional whole as a demonstration of how we explored abstract theoretical perspectives in particular design situations leading to three concrete designed artefacts....

  6. Attraction Propagation: A User-Friendly Interactive Approach for Polyp Segmentation in Colonoscopy Images

    Science.gov (United States)

    Du, Ning; Wang, Xiaofei; Guo, Jianhua; Xu, Meidong

    2016-01-01

    The article raised a user-friendly interactive approach-Attraction Propagation (AP) in segmentation of colorectal polyps. Compared with other interactive approaches, the AP relied on only one foreground seed to get different shapes of polyps, and it can be compatible with pre-processing stage of Computer-Aided Diagnosis (CAD) under the systematically procedure of Optical Colonoscopy (OC). The experimental design was based on challenging distinct datasets that totally includes 1691 OC images, and the results demonstrated that no matter in accuracy or calculating speed, the AP performed better than the state-of-the-art. PMID:27191849

  7. Strategic Sexual Signals: Women's Display versus Avoidance of the Color Red Depends on the Attractiveness of an Anticipated Interaction Partner

    OpenAIRE

    Niesta Kayser, Daniela; Agthe, Maria; Maner, Jon K.

    2016-01-01

    The color red has special meaning in mating-relevant contexts. Wearing red can enhance perceptions of women’s attractiveness and desirability as a potential romantic partner. Building on recent findings, the present study examined whether women’s (N = 74) choice to display the color red is influenced by the attractiveness of an expected opposite-sex interaction partner. Results indicated that female participants who expected to interact with an attractive man displayed red (on clothing, acces...

  8. Cosmological evolution of a complex scalar field with repulsive or attractive self-interaction

    CERN Document Server

    Suárez, Abril

    2016-01-01

    We study the cosmological evolution of a complex scalar field with a self-interaction potential $V(|\\varphi|^2)$, possibly describing self-gravitating Bose-Einstein condensates, using a fully general relativistic treatment. We generalize the hydrodynamic representation of the Klein-Gordon-Einstein equations in the weak field approximation developed in our previous paper. We establish the general equations governing the evolution of a spatially homogeneous complex scalar field in an expanding background. We show how they can be simplified in the fast oscillation regime and derive the equation of state of the scalar field in parametric form for an arbitrary potential. We explicitly consider the case of a quartic potential with repulsive or attractive self-interaction and determine the phase diagram of the scalar field. We show that the transition between the weakly self-interacting regime and the strongly self-interacting regime depends on how the scattering length of the bosons compares with their effective Sc...

  9. Cooperation of Sperm in Two Dimensions: Synchronization, Attraction and Aggregation through Hydrodynamic Interactions

    CERN Document Server

    Yang, Yingzi; Gompper, Gerhard

    2008-01-01

    Sperm swimming at low Reynolds number have strong hydrodynamic interactions when their concentration is high in vivo or near substrates in vitro. The beating tails not only propel the sperm through a fluid, but also create flow fields through which sperm interact with each other. We study the hydrodynamic interaction and cooperation of sperm embedded in a two-dimensional fluid by using a particle-based mesoscopic simulation method, multi-particle collision dynamics (MPC). We analyze the sperm behavior by investigating the relationship between the beating-phase difference and the relative sperm position, as well as the energy consumption. Two effects of hydrodynamic interaction are found, synchronization and attraction. With these hydrodynamic effects, a multi-sperm system shows swarm behavior with a power-law dependence of the average cluster size on the width of the distribution of beating frequencies.

  10. Cooperation of sperm in two dimensions: Synchronization, attraction, and aggregation through hydrodynamic interactions

    Science.gov (United States)

    Yang, Yingzi; Elgeti, Jens; Gompper, Gerhard

    2008-12-01

    Sperm swimming at low Reynolds number have strong hydrodynamic interactions when their concentration is high in vivo or near substrates in vitro. The beating tails not only propel the sperm through a fluid, but also create flow fields through which sperm interact with each other. We study the hydrodynamic interaction and cooperation of sperm embedded in a two-dimensional fluid by using a particle-based mesoscopic simulation method, multiparticle collision dynamics. We analyze the sperm behavior by investigating the relationship between the beating-phase difference and the relative sperm position, as well as the energy consumption. Two effects of hydrodynamic interaction are found, synchronization and attraction. With these hydrodynamic effects, a multisperm system shows swarm behavior with a power-law dependence of the average cluster size on the width of the distribution of beating frequencies.

  11. Dark-soliton-like excitations in the Yang–Gaudin gas of attractively interacting fermions

    Science.gov (United States)

    Shamailov, Sophie S.; Brand, Joachim

    2016-07-01

    Yrast states are the lowest energy states at given non-zero momentum and provide a natural extension of the concept of dark solitons to strongly interacting one-dimensional quantum gases. Here we study the yrast states of the balanced spin-\\tfrac{1}{2} Fermi gas with attractive delta-function interactions in one-dimension with the exactly solvable Yang–Gaudin model. The corresponding Bethe-ansatz equations are solved for finite particle number and in the thermodynamic limit. Properties corresponding to the soliton-like nature of the yrast excitations are calculated including the missing particle number, phase step, and inertial and physical masses. The inertial to physical mass ratio, which is related to the frequency of oscillations in a trapped gas, is found to be unity in the limits of strong and weak attraction and falls to ≈ 0.78 in the crossover regime. This result is contrasted by one-dimensional mean field theory, which predicts a divergent mass ratio in the weakly attractive limit. By means of an exact mapping our results also predict the existence and properties of dark-soliton-like excitations in the super Tonks–Girardeau gas. The prospects for experimental observations are briefly discussed.

  12. Cyclometalated platinum(Ⅱ) complexes with sterically bulky camphor-derived groups as β-diketonate ancillary ligand:a new route to efficiently reducing π-π interactions and Pt-Pt interactions

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    A new series of mono-cyclometalated square planar platinum(Ⅱ) complexes have been synthesized and the single-crystal X-ray structures of complex 1 and 2 have been determined.The complexes have the general formula ppyPt(OO),where ppy is 2-phenylpyridyl,and OO is β-diketonate ancillary ligands with the acyl substituent group in position 3 of(D)-(+)-camphor.Although,like the many Pt(Ⅱ) complexes with square-planar geometry,these complexes have plane stacking modes in crystal structure,the sterically bulky camphor-derived groups compel extensive slipping of the molecular stacking planes,resulting in the negligible overlapping of the aromatic ring fragments between molecules and the considerable Pt-Pt distance.The resolved spectra and a little shifted emission in solid state of complexes show that there is significant reduction of π-π interactions and Pt-Pt interactions,and suggest these complexes may be good candidates for doped phosphorescent organic light emitting diodes(PhOLEDs) and even for nondoped PhOLEDs.

  13. Charge instabilities of the two-dimensional Hubbard model with attractive nearest neighbour interaction

    Science.gov (United States)

    Frésard, Raymond; Steffen, Kevin; Kopp, Thilo

    2016-03-01

    Attractive non-local interactions jointly with repulsive local interaction in a microscopic modelling of electronic Fermi liquids generate a competition between an enhancement of the static charge susceptibility–ultimately signalling charge instability and phase separation–and its correlation induced suppression. We analyse this scenario through the investigation of the extended Hubbard model on a two-dimensional square lattice, using the spin rotation invariant slave-boson representation of Kotliar and Ruckenstein. The quasiparticle density of states, the renormalised effective mass and the Landau parameter F s 0 are presented, whereby the positivity of F s 0 – 1 constitutes a criterion for stability. Van Hove singularities in the density of states support possible charge instabilities. A (negative) next-nearest neighbour hopping parameter t' shifts their positions and produces a tendency towards charge instability even for low filling whereas the t'-controlled particle-hole asymmetry of the correlation driven effective mass is small. A region of instability on account of the attractive interaction V is identified, either at half filling in the absence of strong electronic correlations or, in the case of large on-site interaction U, at densities far from half filling.

  14. Analysis on Patterns of Globally Coupled Phase Oscillators with Attractive and Repulsive Interactions

    Science.gov (United States)

    Wang, Peng-Fei; Ruan, Xiao-Dong; Xu, Zhong-Bin; Fu, Xin

    2015-11-01

    The Hong-Strogatz (HS) model of globally coupled phase oscillators with attractive and repulsive interactions reflects the fact that each individual (oscillator) has its own attitude (attractive or repulsive) to the same environment (mean field). Previous studies on HS model focused mainly on the stable states on Ott-Antonsen (OA) manifold. In this paper, the eigenvalues of the Jacobi matrix of each fixed point in HS model are explicitly derived, with the aim to understand the local dynamics around each fixed point. Phase transitions are described according to relative population and coupling strength. Besides, the dynamics off OA manifold is studied. Supported by the National Basic Research Program of China under Grant No. 2015CB057301, the Applied Research Project of Public Welfare Technology of Zhejiang Province under Grant No. 201SC31109 and China Postdoctoral Science Foundation under Grant No. 2014M560483

  15. Jamming and Attraction of Interacting Run-and-Tumble Random Walkers

    Science.gov (United States)

    Slowman, A. B.; Evans, M. R.; Blythe, R. A.

    2016-05-01

    We study a model of bacterial dynamics where two interacting random walkers perform run-and-tumble motion on a one-dimensional lattice under mutual exclusion and find an exact expression for the probability distribution in the steady state. This stationary distribution has a rich structure comprising three components: a jammed component, where the particles are adjacent and block each other; an attractive component, where the probability distribution for the distance between particles decays exponentially; and an extended component in which the distance between particles is uniformly distributed. The attraction between the particles is sufficiently strong that even in the limit where continuous space is recovered for a finite system, the two walkers spend a finite fraction of time in a jammed configuration. Our results potentially provide a route to understanding the motility-induced phase separation characteristic of active matter from a microscopic perspective.

  16. Non-equilibrium depletion interactions: first things attract, then they repel

    Science.gov (United States)

    Dolata, Benjamin; Zia, Roseanna

    2015-11-01

    Non-Equilibrium depletion interactions in colloidal dispersions are studied theoretically via a combination of asymptotic and numerical solutions of the Smoluchowski equation. A pair of probes at arbitrary separation is driven by an external force at arbitrary orientation through a suspension, deforming the surrounding microstructure. The degree to which the structure is distorted, and the shape of this deformation, depends on the separation between the probes, on the orientation of the pair to the driving force, and on the strength with which the probes are forced relative to the entropic restoring force of the suspension particles. The resultant non-equilibrium osmotic pressure gradients give rise to both drag and interactive forces between the probes. When the external force is zero, the depletion attraction of Asakura and Oosawa is recovered. When an external force is applied, the interactive force can lead either to attraction or repulsion, as well as deterministic re-orientation of the probes relative to the external force, depending on initial separation, orientation, and strength of forcing. The use of this model for interrogation of non-continuum and elastically networked materials is explored.

  17. Multicomponent adhesive hard sphere models and short-ranged attractive interactions in colloidal or micellar solutions

    Science.gov (United States)

    Gazzillo, Domenico; Giacometti, Achille; Fantoni, Riccardo; Sollich, Peter

    2006-11-01

    We investigate the dependence of the stickiness parameters tij=1/(12τij) —where the τij are the conventional Baxter parameters—on the solute diameters σi and σj in multicomponent sticky hard sphere (SHS) models for fluid mixtures of mesoscopic neutral particles. A variety of simple but realistic interaction potentials, utilized in the literature to model short-ranged attractions present in real solutions of colloids or reverse micelles, is reviewed. We consider: (i) van der Waals attractions, (ii) hard-sphere-depletion forces, (iii) polymer-coated colloids, and (iv) solvation effects (in particular hydrophobic bonding and attractions between reverse micelles of water-in-oil microemulsions). We map each of these potentials onto an equivalent SHS model by requiring the equality of the second virial coefficients. The main finding is that, for most of the potentials considered, the size-dependence of tij(T,σi,σj) can be approximated by essentially the same expression, i.e., a simple polynomial in the variable σiσj/σij2 , with coefficients depending on the temperature T , or—for depletion interactions—on the packing fraction η0 of the depletant particles.

  18. Renormalization group analysis of ultracold Fermi gases with two-body attractive interaction

    Science.gov (United States)

    Guo, Xiaoyong; Chi, Zimeng; Zheng, Qiang; Wang, Zaijun

    2016-01-01

    We propose a new functional renormalization group (RG) strategy to investigate the many-body physics of interacting ultracold Fermi gases. By mapping the Ginzburg-Landau (GL) action of Fermi gases onto a complex φ4-model, we can obtain the closed flow equation in the one-loop approximation. An analysis of the emerging RG flow gives the ground state behavior. The Hamiltonian of a Fermi gas with a two-body attractive interaction is used as a demonstration to clarify our treatment. The fixed point structure reveals not only the condensation phase transition, but also the Bardeen-Cooper-Schrieffer (BCS) to Bose-Einstein condensation (BEC) crossover. The effect of the imaginary time renormalization is also discussed. It is shown that for the dynamical field configuration our RG procedure can reproduce the well known theoretical results of BCS-BEC crossover, while under a static approximation the phase transition takes place at a higher critical temperature.

  19. The Effect of Attractive Interactions and Macromolecular Crowding on Crystallins Association.

    Directory of Open Access Journals (Sweden)

    Jiachen Wei

    Full Text Available In living systems proteins are typically found in crowded environments where their effective interactions strongly depend on the surrounding medium. Yet, their association and dissociation needs to be robustly controlled in order to enable biological function. Uncontrolled protein aggregation often causes disease. For instance, cataract is caused by the clustering of lens proteins, i.e., crystallins, resulting in enhanced light scattering and impaired vision or blindness. To investigate the molecular origins of cataract formation and to design efficient treatments, a better understanding of crystallin association in macromolecular crowded environment is needed. Here we present a theoretical study of simple coarse grained colloidal models to characterize the general features of how the association equilibrium of proteins depends on the magnitude of intermolecular attraction. By comparing the analytic results to the available experimental data on the osmotic pressure in crystallin solutions, we identify the effective parameters regimes applicable to crystallins. Moreover, the combination of two models allows us to predict that the number of binding sites on crystallin is small, i.e. one to three per protein, which is different from previous estimates. We further observe that the crowding factor is sensitive to the size asymmetry between the reactants and crowding agents, the shape of the protein clusters, and to small variations of intermolecular attraction. Our work may provide general guidelines on how to steer the protein interactions in order to control their association.

  20. Urgent Biophilia: Human-Nature Interactions and Biological Attractions in Disaster Resilience

    Directory of Open Access Journals (Sweden)

    Keith G. Tidball

    2012-06-01

    Full Text Available This contribution builds upon contemporary work on principles of biological attraction as well as earlier work on biophilia while synthesizing literatures on restorative environments, community-based ecological restoration, and both community and social-ecological disaster resilience. It suggests that when humans, faced with a disaster, as individuals and as communities and populations, seek engagement with nature to further their efforts to summon and demonstrate resilience in the face of a crisis, they exemplify an urgent biophilia. This urgent biophilia represents an important set of human-nature interactions in SES characterized by hazard, disaster, or vulnerability, often appearing in the 'backloop' of the adaptive cycle. The relationships that human-nature interactions have to other components within interdependent systems at many different scales may be one critical source of resilience in disaster and related contexts. In other words, the affinity we humans have for the rest of nature, the process of remembering that attraction, and the urge to express it through creation of restorative environments, which may also restore or increase ecological function, may confer resilience across multiple scales. In making this argument, the paper also represents a novel contribution to further theorizing alternatives to anthropocentric understandings of human-nature relations, and strongly makes the case for humans as part of, not separate from, ecosystems.

  1. Static and dynamic phases for magnetic vortex matter with attractive and repulsive interactions

    International Nuclear Information System (INIS)

    Exotic vortex states with long range attraction and short range repulsion have recently been proposed to arise in certain superconducting hybrid structures such as type-I/type-II layered systems as well as multi-band superconductors. In previous work it has been shown that such systems can form clump or phase separated states, but little is known about how they behave in the presence of pinning and under an applied drive. Using large scale simulations we examine the static and dynamic properties of such vortex states interacting with random and periodic pinning. In the absence of pinning this system does not form patterns but instead undergoes complete phase separation. When pinning is present there is a transition from inhomogeneous to homogeneous vortex configurations similar to a wetting phenomenon. Under an applied drive, a dynamical dewetting process can occur from a strongly pinned homogeneous state into pattern forming states, such as moving stripes that are aligned with the direction of drive or moving labyrinth or clump phases. We show that a signature of the exotic vortex interactions observable with transport measurements is a robust double peak feature in the differential resistance curves. Our results should be valuable for determining whether such vortex interactions are occurring in these systems and also for addressing the general problem of systems with competing interactions in the presence of random and periodic pinning. (paper)

  2. Pilot whales attracted to killer whale sounds: acoustically-mediated interspecific interactions in cetaceans.

    Science.gov (United States)

    Curé, Charlotte; Antunes, Ricardo; Samarra, Filipa; Alves, Ana Catarina; Visser, Fleur; Kvadsheim, Petter H; Miller, Patrick J O

    2012-01-01

    In cetaceans' communities, interactions between individuals of different species are often observed in the wild. Yet, due to methodological and technical challenges very little is known about the mediation of these interactions and their effect on cetaceans' behavior. Killer whales (Orcinus orca) are a highly vocal species and can be both food competitors and potential predators of many other cetaceans. Thus, the interception of their vocalizations by unintended cetacean receivers may be particularly important in mediating interspecific interactions. To address this hypothesis, we conducted playbacks of killer whale vocalizations recorded during herring-feeding activity to free-ranging long-finned pilot whales (Globicephala melas). Using a multi-sensor tag, we were able to track the whales and to monitor changes of their movements and social behavior in response to the playbacks. We demonstrated that the playback of killer whale sounds to pilot whales induced a clear increase in group size and a strong attraction of the animals towards the sound source. These findings provide the first experimental evidence that the interception of heterospecific vocalizations can mediate interactions between different cetacean species in previously unrecognized ways. PMID:23300613

  3. Pilot whales attracted to killer whale sounds: acoustically-mediated interspecific interactions in cetaceans.

    Directory of Open Access Journals (Sweden)

    Charlotte Curé

    Full Text Available In cetaceans' communities, interactions between individuals of different species are often observed in the wild. Yet, due to methodological and technical challenges very little is known about the mediation of these interactions and their effect on cetaceans' behavior. Killer whales (Orcinus orca are a highly vocal species and can be both food competitors and potential predators of many other cetaceans. Thus, the interception of their vocalizations by unintended cetacean receivers may be particularly important in mediating interspecific interactions. To address this hypothesis, we conducted playbacks of killer whale vocalizations recorded during herring-feeding activity to free-ranging long-finned pilot whales (Globicephala melas. Using a multi-sensor tag, we were able to track the whales and to monitor changes of their movements and social behavior in response to the playbacks. We demonstrated that the playback of killer whale sounds to pilot whales induced a clear increase in group size and a strong attraction of the animals towards the sound source. These findings provide the first experimental evidence that the interception of heterospecific vocalizations can mediate interactions between different cetacean species in previously unrecognized ways.

  4. Modeling Flocks and Prices: Jumping Particles with an Attractive Interaction (shortened version)

    CERN Document Server

    Balazs, Marton; Toth, Balint

    2011-01-01

    We introduce and investigate a new model of a finite number of particles jumping forward on the real line. The jump lengths are independent of everything, but the jump rate of each particle depends on the relative position of the particle compared to the center of mass of the system. The rates are higher for those left behind, and lower for those ahead of the center of mass, providing an attractive interaction keeping the particles together. We prove that in the fluid limit, as the number of particles goes to infinity, the evolution of the system is described by a mean field equation that exhibits traveling wave solutions. A connection to extreme value statistics is also provided.

  5. Bright Solitons in an Atomic Tunnel Array with Either Attractive or Repulsive Atom-Atom Interactions

    Institute of Scientific and Technical Information of China (English)

    YANG Xiao-Xue; YOU Jun; WU Ying

    2004-01-01

    @@ Taking a coherent state representation, we derive the nonlinear Schrodinger-type differential-difference equations from the quantized model of an array of traps containing Bose-Einstein condensates and linked by the tunnelling process among the adjacent traps. It is shown that no matter whether two-body interactions among atoms are repulsive or attractive, a nearly uniform atom distribution can evolve into a bright soliton-type localized ensemble of atoms and a lump of atom distribution can also be smeared out by redistributing atoms among traps under appropriate initial phase differences of atoms in adjacent traps. These two important features originate from the tailoring effect of the initial phase conditions in coherent tunnelling processes, which differs crucially from the previous tailoring effect coming mainly from the periodicity of optical lattices.

  6. Large attractive depletion interactions in soft repulsive-sphere binary mixtures.

    Science.gov (United States)

    Cinacchi, Giorgio; Martínez-Ratón, Yuri; Mederos, Luis; Navascués, Guillermo; Tani, Alessandro; Velasco, Enrique

    2007-12-01

    We consider binary mixtures of soft repulsive spherical particles and calculate the depletion interaction between two big spheres mediated by the fluid of small spheres, using different theoretical and simulation methods. The validity of the theoretical approach, a virial expansion in terms of the density of the small spheres, is checked against simulation results. Attention is given to the approach toward the hard-sphere limit and to the effect of density and temperature on the strength of the depletion potential. Our results indicate, surprisingly, that even a modest degree of softness in the pair potential governing the direct interactions between the particles may lead to a significantly more attractive total effective potential for the big spheres than in the hard-sphere case. This might lead to significant differences in phase behavior, structure, and dynamics of a binary mixture of soft repulsive spheres. In particular, a perturbative scheme is applied to predict the phase diagram of an effective system of big spheres interacting via depletion forces for a size ratio of small and big spheres of 0.2; this diagram includes the usual fluid-solid transition but, in the soft-sphere case, the metastable fluid-fluid transition, which is probably absent in hard-sphere mixtures, is close to being stable with respect to direct fluid-solid coexistence. From these results, the interesting possibility arises that, for sufficiently soft repulsive particles, this phase transition could become stable. Possible implications for the phase behavior of real colloidal dispersions are discussed. PMID:18067358

  7. Strategic Sexual Signals: Women's Display versus Avoidance of the Color Red Depends on the Attractiveness of an Anticipated Interaction Partner.

    Directory of Open Access Journals (Sweden)

    Daniela Niesta Kayser

    Full Text Available The color red has special meaning in mating-relevant contexts. Wearing red can enhance perceptions of women's attractiveness and desirability as a potential romantic partner. Building on recent findings, the present study examined whether women's (N = 74 choice to display the color red is influenced by the attractiveness of an expected opposite-sex interaction partner. Results indicated that female participants who expected to interact with an attractive man displayed red (on clothing, accessories, and/or makeup more often than a baseline consisting of women in a natural environment with no induced expectation. In contrast, when women expected to interact with an unattractive man, they eschewed red, displaying it less often than in the baseline condition. Findings are discussed with respect to evolutionary and cultural perspectives on mate evaluation and selection.

  8. Strategic Sexual Signals: Women's Display versus Avoidance of the Color Red Depends on the Attractiveness of an Anticipated Interaction Partner.

    Science.gov (United States)

    Niesta Kayser, Daniela; Agthe, Maria; Maner, Jon K

    2016-01-01

    The color red has special meaning in mating-relevant contexts. Wearing red can enhance perceptions of women's attractiveness and desirability as a potential romantic partner. Building on recent findings, the present study examined whether women's (N = 74) choice to display the color red is influenced by the attractiveness of an expected opposite-sex interaction partner. Results indicated that female participants who expected to interact with an attractive man displayed red (on clothing, accessories, and/or makeup) more often than a baseline consisting of women in a natural environment with no induced expectation. In contrast, when women expected to interact with an unattractive man, they eschewed red, displaying it less often than in the baseline condition. Findings are discussed with respect to evolutionary and cultural perspectives on mate evaluation and selection. PMID:26960135

  9. Sterically allowed configuration space for amino acid dipeptides

    Science.gov (United States)

    Caballero, Diego; Maatta, Jukka; Sammalkorpi, Maria; O'Hern, Corey; Regan, Lynne

    2014-03-01

    Despite recent improvements in computational methods for protein design, we still lack a quantitative, predictive understanding of the intrinsic propensities for amino acids to be in particular backbone or side-chain conformations. This question has remained unsettled for years because of the discrepancies between different experimental approaches. To address it, I performed all-atom hard-sphere simulations of hydrophobic residues with stereo-chemical constraints and non-attractive steric interactions between non-bonded atoms for ALA, ILE, LEU and VAL dipeptide mimetics. For these hard-sphere MD simulations, I show that transitions between α-helix and β-sheet structures only occur when the bond angle τ(N -Cα - C) >110° , and the probability distribution of bond angles for structures in the `bridge' region of ϕ- ψ space is shifted to larger angles compared to that in other regions. In contrast, the relevant bond-angle distributions obtained from most molecular dynamics packages are broader and shifter to larger values. I encounter similar correlations between bond angles and side-chain dihedral angles. The success of these studies is an argument for re-incorporating local stereochemical constraints into computational protein design methodology.

  10. Thermodynamics of one-dimensional SU(4) and SU(6) fermions with attractive interactions

    CERN Document Server

    Hoffman, M D; Porter, W J; Drut, J E

    2016-01-01

    Motivated by advances in the manipulation and detection of ultracold atoms with multiple internal degrees of freedom, we present a finite-temperature lattice Monte Carlo calculation of the density and pressure equations of state, as well as Tan's contact, of attractively interacting SU(4)- and SU(6)-symmetric fermion systems in one spatial dimension. We also furnish a non-perturbative proof of a universal relation whereby the dynamics of the SU(2) case completely determines the virial coefficients of the SU($N_f$) case. These one-dimensional systems are appealing because they can be experimentally realized in highly constrained traps and because of the dominant role played by correlations. The latter are typically non-perturbative and are crucial for understanding ground states and quantum phase transitions. While quantum fluctuations are typically overpowered by thermal ones in 1D and 2D at any finite temperature, we find that quantum effects do leave their imprint in thermodynamic quantities. Our calculatio...

  11. Steric Effects Govern the Photoactivation of Phytochromes.

    Science.gov (United States)

    Falklöf, Olle; Durbeej, Bo

    2016-04-01

    Phytochromes constitute a superfamily of photoreceptor proteins existing in two forms that absorb red (Pr) and far-red (Pfr) light. Although it is well-known that the conversion of Pr into Pfr (the biologically active form) is triggered by a Z→E photoisomerization of the linear tetrapyrrole chromophore, direct evidence is scarce as to why this reaction always occurs at the methine bridge between pyrrole rings C and D. Here, we present hybrid quantum mechanics/molecular mechanics calculations based on a high-resolution Pr crystal structure of Deinococcus radiodurans bacteriophytochrome to investigate the competition between all possible photoisomerizations at the three different (AB, BC and CD) methine bridges. The results demonstrate that steric interactions with the protein are a key discriminator between the different reaction channels. In particular, it is found that such interactions render photoisomerizations at the AB and BC bridges much less probable than photoisomerization at the CD bridge. PMID:26756452

  12. The Effects of Relaxation and Cognitive Expectancy on Attraction in a Social Interaction.

    Science.gov (United States)

    Wilson, Midge

    One approach to searching for determinants of interpersonal attraction involves the altering and studying of physiological arousal, psychological stress, and moods. On the basis of the reinforcement-affect model of attraction, it was hypothesized that the positive feelings obtained from undergoing relaxation exercises could serve to enhance…

  13. Gazing Behavior During Mixed-Sex Interactions: Sex and Attractiveness Effects

    NARCIS (Netherlands)

    Straaten, I. van; Holland, R.W.; Finkenauer, C.; Hollenstein, T.; Engels, R.C.M.E.

    2010-01-01

    We investigated to what extent the length of people's gazes during conversations with opposite-sex persons is affected by the physical attractiveness of the partner. Single participants (N = 115) conversed for 5 min with confederates who were rated either as low or high on physical attractiveness. F

  14. Interaction Parameter (¿); Expansion Factor (¿); Steric Hindrance Factor (¿); and Shieldin Function F(¿); for the System PEA¿Organic Solvents by Intrinsic Viscosity Measurements

    OpenAIRE

    Martha L. Cecopieri Gómez; Joaquín Palacios Alquisira

    2005-01-01

    In this work we present experimental data of the Flory binary interaction parameter, χ, of poly (ethylene adipate) PEA, a plasticizer material. We have used the viscometric method for measuring dilute PEA solutions in good solvents: benzene, chloroform and acetone. A procedure based on the Stockmayer-Fixman, (SF), hydrodynamic solutions theory, allows us to evaluate some thermodynamic parameters via the intrinsic viscosity [η], measured in several good so...

  15. Equilibrium Bundle Size of Rodlike Polyelectrolytes with Counterion-Induced Attractive Interactions

    OpenAIRE

    Henle, Mark L.; Pincus, Philip A.

    2004-01-01

    Multivalent counterions can induce an effective attraction between like-charged rodlike polyelectrolytes, leading to the formation of polelectrolyte bundles. In this paper, we calculate the equilibrium bundle size using a simple model in which the attraction between polyelectrolytes (assumed to be pairwise additive) is treated phenomenologically. If the counterions are point-like, they almost completely neutralize the charge of the bundle, and the equilibrium bundle size diverges. When the co...

  16. Intra-cellular transport by single-headed kinesin KIF1A: effects of single-motor mechano-chemistry and steric interactions

    CERN Document Server

    Greulich, P; Garai, A; Nishinari, K; Schadschneider, A; Chowdhury, Debashish; Garai, Ashok; Greulich, Philip; Nishinari, Katsuhiro; Schadschneider, Andreas

    2006-01-01

    In eukaryotic cells, many motor proteins can move simultaneously on a single microtubule track. This leads to interesting collective phenomena like jamming. Recently we reported ({\\it Phys. Rev. Lett. {\\bf 95}, 118101 (2005)}) a lattice-gas model which describes traffic of unconventional (single-headed) kinesins KIF1A. Here we generalize this model, introducing a novel interaction parameter $c$, to account for an interesting mechano-chemical process which has not been considered in any earlier model. We have been able to extract all the parameters of the model, except $c$, from experimentally measured quantities. In contrast to earlier models of intra-cellular molecular motor traffic, our model assigns distinct ``chemical'' (or, conformational) states to each kinesin to account for the hydrolysis of ATP, the chemical fuel of the motor. Our model makes experimentally testable theoretical predictions. We determine the phase diagram of the model in planes spanned by experimentally controllable parameters, namely...

  17. Eigenvalue Attraction

    Science.gov (United States)

    Movassagh, Ramis

    2016-02-01

    We prove that the complex conjugate (c.c.) eigenvalues of a smoothly varying real matrix attract (Eq. 15). We offer a dynamical perspective on the motion and interaction of the eigenvalues in the complex plane, derive their governing equations and discuss applications. C.c. pairs closest to the real axis, or those that are ill-conditioned, attract most strongly and can collide to become exactly real. As an application we consider random perturbations of a fixed matrix M. If M is Normal, the total expected force on any eigenvalue is shown to be only the attraction of its c.c. (Eq. 24) and when M is circulant the strength of interaction can be related to the power spectrum of white noise. We extend this by calculating the expected force (Eq. 41) for real stochastic processes with zero-mean and independent intervals. To quantify the dominance of the c.c. attraction, we calculate the variance of other forces. We apply the results to the Hatano-Nelson model and provide other numerical illustrations. It is our hope that the simple dynamical perspective herein might help better understanding of the aggregation and low density of the eigenvalues of real random matrices on and near the real line respectively. In the appendix we provide a Matlab code for plotting the trajectories of the eigenvalues.

  18. Angry and Beautiful: The Interactive Effect of Facial Expression and Attractiveness on Time Perception

    Directory of Open Access Journals (Sweden)

    Jasmina Tomas

    2016-07-01

    Full Text Available Time perception is an adaptive phenomenon that enables everyday functioning, although many of its aspects remain unknown. Previous studies have resulted in new insights regarding this phenomenon, indicating an overestimation of emotional faces presentations, compared to neutral ones. The aim of the present study was to explore if this effect due to emotional expression would be modulated by the attractiveness of the perceived face. Female participants performed a temporal bisection task during which they evaluated elapsed time of female faces presentation differing in facial expression (angry and neutral expression and attractiveness (attractive and unattractive face for seven different stimuli durations (400-1.600 ms. Results indicate a systematic overestimation of angry faces duration compared to neutral ones, but only for the attractive face condition, the effect that did not occur for the unattractive face. These findings support the arousal-based models of time perception, indicating that arousal affects time perception mechanism resulting in an overestimation of the perceived time.

  19. CC-LR: Providing Interactive, Challenging and Attractive Collaborative Complex Learning Resources

    Science.gov (United States)

    Caballé, S.; Mora, N.; Feidakis, M.; Gañán, D.; Conesa, J.; Daradoumis, T.; Prieto, J.

    2014-01-01

    Many researchers argue that students must be meaningfully engaged in the learning resources for effective learning to occur. However, current online learners still report a problematic lack of attractive and challenging learning resources that engage them in the learning process. This endemic problem is even more evident in online collaborative…

  20. Nonlinear Dynamics of Ultra-Cold Gas: Collapse of Bose Gas With Attractive Interaction

    OpenAIRE

    Flambaum, V. V.; Kuznetsov, E.

    2012-01-01

    Solutions for the Nonlinear Schrodinger equation for collapsing Bose gas with attraction. This is a copy of the paper published in 1992 in Proceedings of NATO Advanced Research workshop on Singularities in Fluids, Plasmas and Optics (Heraklion, Greece) edited by R.E. Caflisch and G.C. Papanicolaou (Kluwer Academic).

  1. Effect of attractive interactions on the water-like anomalies of a core-softened model potential

    Energy Technology Data Exchange (ETDEWEB)

    Pant, Shashank [Department of Chemical Sciences, Indian Institute of Science Education and Research-Kolkata, Mohanpur-741252 (India); Gera, Tarun [Department of Chemistry, Indian Institute of Technology-Delhi, New Delhi, 110016 (India); Choudhury, Niharendu, E-mail: nihcho@barc.gov.in, E-mail: niharc2002@yahoo.com [Theoretical Chemistry Section, Bhabha Atomic Research Centre, Mumbai-400 085 (India)

    2013-12-28

    It is now well established that water-like anomalies can be reproduced by a spherically symmetric potential with two length scales, popularly known as core-softened potential. In the present study we aim to investigate the effect of attractive interactions among the particles in a model fluid interacting with core-softened potential on the existence and location of various water-like anomalies in the temperature-pressure plane. We employ extensive molecular dynamic simulations to study anomalous nature of various order parameters and properties under isothermal compression. Order map analyses have also been done for all the potentials. We observe that all the systems with varying depth of attractive wells show structural, dynamic, and thermodynamic anomalies. As many of the previous studies involving model water and a class of core softened potentials have concluded that the structural anomaly region encloses the diffusion anomaly region, which in turn, encloses the density anomaly region, the same pattern has also been observed in the present study for the systems with less depth of attractive well. For the systems with deeper attractive well, we observe that the diffusion anomaly region shifts toward higher densities and is not always enclosed by the structural anomaly region. Also, density anomaly region is not completely enclosed by diffusion anomaly region in this case.

  2. Effect of attractive interactions on the water-like anomalies of a core-softened model potential.

    Science.gov (United States)

    Pant, Shashank; Gera, Tarun; Choudhury, Niharendu

    2013-12-28

    It is now well established that water-like anomalies can be reproduced by a spherically symmetric potential with two length scales, popularly known as core-softened potential. In the present study we aim to investigate the effect of attractive interactions among the particles in a model fluid interacting with core-softened potential on the existence and location of various water-like anomalies in the temperature-pressure plane. We employ extensive molecular dynamic simulations to study anomalous nature of various order parameters and properties under isothermal compression. Order map analyses have also been done for all the potentials. We observe that all the systems with varying depth of attractive wells show structural, dynamic, and thermodynamic anomalies. As many of the previous studies involving model water and a class of core softened potentials have concluded that the structural anomaly region encloses the diffusion anomaly region, which in turn, encloses the density anomaly region, the same pattern has also been observed in the present study for the systems with less depth of attractive well. For the systems with deeper attractive well, we observe that the diffusion anomaly region shifts toward higher densities and is not always enclosed by the structural anomaly region. Also, density anomaly region is not completely enclosed by diffusion anomaly region in this case. PMID:24387380

  3. Effect of attractive interactions on the water-like anomalies of a core-softened model potential

    International Nuclear Information System (INIS)

    It is now well established that water-like anomalies can be reproduced by a spherically symmetric potential with two length scales, popularly known as core-softened potential. In the present study we aim to investigate the effect of attractive interactions among the particles in a model fluid interacting with core-softened potential on the existence and location of various water-like anomalies in the temperature-pressure plane. We employ extensive molecular dynamic simulations to study anomalous nature of various order parameters and properties under isothermal compression. Order map analyses have also been done for all the potentials. We observe that all the systems with varying depth of attractive wells show structural, dynamic, and thermodynamic anomalies. As many of the previous studies involving model water and a class of core softened potentials have concluded that the structural anomaly region encloses the diffusion anomaly region, which in turn, encloses the density anomaly region, the same pattern has also been observed in the present study for the systems with less depth of attractive well. For the systems with deeper attractive well, we observe that the diffusion anomaly region shifts toward higher densities and is not always enclosed by the structural anomaly region. Also, density anomaly region is not completely enclosed by diffusion anomaly region in this case

  4. Effect of residual attractive interactions in size asymmetric colloidal mixtures: Theoretical analysis and predictions.

    Science.gov (United States)

    Germain, Ph

    2010-07-28

    We analyze the influence of residual attractions on the static and some dynamic properties of size asymmetric mixtures of "hard-sphere-like" colloids. These attractions, usually neglected in the theoretical analysis, are characterized by a very short range and a moderate strength reflecting the underlying microscopic structure of the colloidal particles. Their effect on the potentials of mean force is analyzed from analytical expressions obtained from low density expansions. The effective potential of the big particle fluid is next considered. An analytical expression is proposed for estimating the deviation with respect to the hard sphere depletion potential. This case is compared to that of mixtures with noninteracting depletants. The important consequences on the binodals and the glass transition lines of the effective fluid are discussed in both cases. This study is next extended to other properties-the specific heat and the low shear viscosity-which incorporate contributions from the two components of the binary mixture. PMID:20687684

  5. Effect of residual attractive interactions in size asymmetric colloidal mixtures: Theoretical analysis and predictions

    Science.gov (United States)

    Germain, Ph.

    2010-07-01

    We analyze the influence of residual attractions on the static and some dynamic properties of size asymmetric mixtures of "hard-sphere-like" colloids. These attractions, usually neglected in the theoretical analysis, are characterized by a very short range and a moderate strength reflecting the underlying microscopic structure of the colloidal particles. Their effect on the potentials of mean force is analyzed from analytical expressions obtained from low density expansions. The effective potential of the big particle fluid is next considered. An analytical expression is proposed for estimating the deviation with respect to the hard sphere depletion potential. This case is compared to that of mixtures with noninteracting depletants. The important consequences on the binodals and the glass transition lines of the effective fluid are discussed in both cases. This study is next extended to other properties—the specific heat and the low shear viscosity—which incorporate contributions from the two components of the binary mixture.

  6. Urgent Biophilia: Human-Nature Interactions and Biological Attractions in Disaster Resilience

    OpenAIRE

    Keith G. Tidball

    2012-01-01

    This contribution builds upon contemporary work on principles of biological attraction as well as earlier work on biophilia while synthesizing literatures on restorative environments, community-based ecological restoration, and both community and social-ecological disaster resilience. It suggests that when humans, faced with a disaster, as individuals and as communities and populations, seek engagement with nature to further their efforts to summon and demonstrate resilience in the face of a ...

  7. Rheology of Attractive Emulsions

    OpenAIRE

    Datta, Sujit S.; Gerrard, Dustin D.; Rhodes, Travers S.; Mason, Thomas G.; Weitz, David A.

    2012-01-01

    We show how attractive interactions dramatically influence emulsion rheology. Unlike the repulsive case, attractive emulsions below random close packing, RCP, can form soft gel-like elastic solids. However, above RCP, attractive and repulsive emulsions have similar elasticities. Such compressed attractive emulsions undergo an additional shear-driven relaxation process during yielding. Our results suggest that attractive emulsions begin to yield at weak points through the breakage of bonds, an...

  8. Diffusion and partitioning of macromolecules in casein microgels: evidence for size-dependent attractive interactions in a dense protein system.

    Science.gov (United States)

    Peixoto, Paulo D S; Bouchoux, Antoine; Huet, Sébastien; Madec, Marie-Noëlle; Thomas, Daniel; Floury, Juliane; Gésan-Guiziou, Geneviève

    2015-02-10

    Understanding the mechanisms that determine the diffusion and interaction of macromolecules (such as proteins and polysaccharides) that disperse through dense media is an important fundamental issue in the development of innovative technological and medical applications. In the current work, the partitioning and diffusion of macromolecules of different sizes (from 4 to 10 nm in diameter) and shapes (linear or spherical) within dispersions of casein micelles (a protein microgel) is studied. The coefficients for diffusion and partition are measured using FRAP (fluorescence recovery after photobleaching) and analyzed with respect to the structural characteristics of the microgel determined by the use of TEM (transmission electron microscopy) tomography. The results show that the casein microgel displays a nonspecific attractive interaction for all macromolecules studied. When the macromolecular probes are spherical, this affinity is clearly size-dependent, with stronger attraction for the larger probes. The current data show that electrostatic effects cannot account for such an attraction. Rather, nonspecific hydration molecular forces appear to explain these results. These findings show how weak nonspecific forces affect the diffusion and partitioning of proteins and polysaccharides in a dense protein environment. These results could be useful to better understand the mechanisms of diffusion and partitioning in other media such as cells and tissues. Furthermore, there arises the possibility of using the casein micelle as a size-selective molecular device. PMID:25604622

  9. Pilot Whales Attracted to Killer Whale Sounds: Acoustically-Mediated Interspecific Interactions in Cetaceans

    NARCIS (Netherlands)

    Cure, C.; Antunes, R.; Samarra, F.; Alves, A.C.; Visser, F.; Kvadsheim, P.H.; Miller, P.J.O.

    2012-01-01

    In cetaceans’ communities, interactions between individuals of different species are often observed in the wild. Yet, due to methodological and technical challenges very little is known about the mediation of these interactions and their effect on cetaceans’ behavior. Killer whales (Orcinus orca) ar

  10. Beauty is more attractive: Particle Production and Moduli trapping with Higher Dimensional Interaction

    CERN Document Server

    Enomoto, Seishi; Maekawa, Nobuhiro; Matsuda, Tomohiro

    2013-01-01

    We study quantum effects on moduli dynamics arising from the particle production near the enhanced symmetry point (ESP). We paid special attention to the non-conventional interactions, which are suppressed by the cutoff scale of the effective action but the power of the field is larger. This kind of interaction is sometimes called the "higher dimensional" interaction. Considering the higher dimensional interaction, we find that the particle production is significant in a large area, which is even larger than the area that is expected from the conventional interaction. It is possible to find this possibility from the trivial adiabatic condition; however the quantitative estimation of the particle production and the trapping of the field in motion are far from trivial. In this paper we study the particle production and the trapping in detail, using both the analytical and the numerical calculations, to find a clear and intuitive result that supports trapping in a vast variety of theories. Our study shows that t...

  11. Two-dimensional symbiotic solitons and vortices in binary condensates with attractive cross-species interaction

    CERN Document Server

    Ma, Xuekai; Malomed, Boris A; Meier, Torsten; Schumacher, Stefan

    2016-01-01

    We consider a two-dimensional (2D) two-component spinor system with cubic attraction between the components and intra-species self-repulsion, which may be realized in atomic Bose-Einstein condensates, as well as in a quasi-equilibrium condensate of microcavity polaritons. Including a 2D spatially periodic potential, which is necessary for the stabilization of the system against the critical collapse, we use detailed numerical calculations and an analytical variational approximation (VA) to predict the existence and stability of several types of 2D symbiotic solitons in the spinor system. Stability ranges are found for symmetric and asymmetric symbiotic fundamental solitons and vortices, including hidden-vorticity (HV) modes, with opposite vorticities in the two components. The VA produces exceptionally accurate predictions for the fundamental solitons and vortices. The fundamental solitons, both symmetric and asymmetric ones, are completely stable, in either case when they exist as gap solitons or regular one...

  12. Polydimethylsiloxane (PDMS Coating onto Magnetic Nanoparticles Induced by Attractive Electrostatic Interaction

    Directory of Open Access Journals (Sweden)

    Carina Sötebier

    2012-05-01

    Full Text Available In this article, we present an efficient synthesis pathway of polydimethylsiloxane (PDMS coated magnetic nanoparticles from hydrophilic polyacrylate coated ferrofluids (NPPAA. A block copolymer based on polydimethylsiloxane is selected for its propensity to interact with the carboxylate functions on the NPPAA. The interaction is due to negative charges on NPPAA and positive ones on the amphiphilic copolymer. The synthesis is achieved by interfacial interaction, simplifying the purification of the PDMS-coated nanoparticles (NPPDMS from subproducts such as ions and water. NPPDMS are well dispersed in hydrophobic solvents (toluene, diethyl ether and can then be embedded into a curable PDMS polymer.

  13. Distance-Dependent Attractive and Repulsive Interactions of Bulky Alkyl Groups.

    Science.gov (United States)

    Hwang, Jungwun; Li, Ping; Smith, Mark D; Shimizu, Ken D

    2016-07-01

    The stabilizing and destabilizing effects of alkyl groups on an aromatic stacking interaction were experimentally measured in solution. The size (Me, Et, iPr, and tBu) and position (meta and para) of the alkyl groups were varied in a molecular balance model system designed to measure the strength of an intramolecular aromatic interaction. Opposite stability trends were observed for alkyl substituents at different positions on the aromatic rings. At the closer meta-position, smaller groups were stabilizing and larger groups were destabilizing. Conversely, at the farther para-position, the larger alkyl groups were systematically more stabilizing with the bulky tBu group forming the strongest stabilizing interaction. X-ray crystal structures showed that the stabilizing interactions of the small meta-alkyl and large para-alkyl groups were due to their similar distances and van der Waals contact areas with the edge of opposing aromatic ring. PMID:27159670

  14. Role of attractive methane-water interactions in the potential of mean force between methane molecules in water

    CERN Document Server

    Asthagiri, D; Pratt, Lawrence R

    2008-01-01

    On the basis of a gaussian quasi-chemical model of hydration, a model of non van der Waals character, we explore the role of attractive methane-water interactions in the hydration of methane and in the potential of mean force between two methane molecules in water. We find that the hydration of methane is dominated by packing and a mean-field energetic contribution. Contributions beyond the mean-field term are unimportant in the hydration phenomena for a hydrophobic solute such as methane. Attractive solute-water interactions make a net repulsive contribution to these pair potentials of mean force. With no conditioning, the observed distributions of binding energies are super-gaussian and can be effectively modeled by a Gumbel (extreme value) distribution. This further supports the view that the characteristic form of the unconditioned distribution in the high-e tail is due to energetic interactions with a small number of molecules. Generalized extreme value distributions also effectively model the results wi...

  15. In live interaction, does familiarity promote attraction or contempt? Reply to Norton, Frost, and Ariely (2011).

    Science.gov (United States)

    Reis, Harry T; Maniaci, Michael R; Caprariello, Peter A; Eastwick, Paul W; Finkel, Eli J

    2011-09-01

    In this reply, we address and refute each of Norton, Frost, and Ariely's (see record 2011-18560-001) specific objections to the conclusion that, ceteris paribus, familiarity breeds liking in live interaction. In particular, we reiterate the importance of studying live interaction rather than decontextualized processes. These rebuttals notwithstanding, we concur with Norton et al.'s call for an integrative model that encompasses both Norton, Frost, and Ariely's (see record 2006-23056-008) results and ours (see record 2011-04644-001), and we point readers toward a description of a possible model presented in our original article. PMID:21859228

  16. Positioning a "Mature" Self in Interactive Practices: How Adolescent Males Negotiate "Physical Attraction" in Group Talk

    Science.gov (United States)

    Korobov, Neill; Bamberg, Michael

    2004-01-01

    This article presents a discursive psychological approach in examining the ways that adolescent boys (ages 12-15 years) accomplish a sense of "maturity" by bringing off and managing certain features of "heterosexuality" in group interaction. We focus on and analyse moments when the boys negotiate implicit challenges, make evaluations and offer…

  17. Deterministic folding: The role of entropic forces and steric specificities

    Science.gov (United States)

    da Silva, Roosevelt A.; da Silva, M. A. A.; Caliri, A.

    2001-03-01

    The inverse folding problem of proteinlike macromolecules is studied by using a lattice Monte Carlo (MC) model in which steric specificities (nearest-neighbors constraints) are included and the hydrophobic effect is treated explicitly by considering interactions between the chain and solvent molecules. Chemical attributes and steric peculiarities of the residues are encoded in a 10-letter alphabet and a correspondent "syntax" is provided in order to write suitable sequences for the specified target structures; twenty-four target configurations, chosen in order to cover all possible values of the average contact order χ (0.2381⩽χ⩽0.4947 for this system), were encoded and analyzed. The results, obtained by MC simulations, are strongly influenced by geometrical properties of the native configuration, namely χ and the relative number φ of crankshafts-type structures: For χprotein folding process.

  18. Attracting STEM talent: do STEM students prefer traditional or work/life-interaction labs?

    Directory of Open Access Journals (Sweden)

    William C DeFraine

    Full Text Available The demand for employees trained in science, technology, engineering, and mathematics (STEM fields continues to increase, yet the number of Millennial students pursuing STEM is not keeping pace. We evaluated whether this shortfall is associated with Millennials' preference for flexibility and work/life-interaction in their careers-a preference that may be inconsistent with the traditional idea of a science career endorsed by many lab directors. Two contrasting approaches to running STEM labs and training students were explored, and we created a lab recruitment video depicting each. The work-focused video emphasized the traditional notions of a science lab, characterized by long work hours and a focus on individual achievement and conducting research above all else. In contrast, the work/life-interaction-focused video emphasized a more progressive view - lack of demarcation between work and non-work lives, flexible hours, and group achievement. In Study 1, 40 professors rated the videos, and the results confirmed that the two lab types reflected meaningful real-world differences in training approaches. In Study 2, we recruited 53 current and prospective graduate students in STEM fields who displayed high math-identification and a commitment to science careers. In a between-subjects design, they watched one of the two lab-recruitment videos, and then reported their anticipated sense of belonging to and desire to participate in the lab depicted in the video. Very large effects were observed on both primary measures: Participants who watched the work/life-interaction-focused video reported a greater sense of belonging to (d = 1.49 and desire to participate in (d = 1.33 the lab, relative to participants who watched the work-focused video. These results suggest Millennials possess a strong desire for work/life-interaction, which runs counter to the traditional lab-training model endorsed by many lab directors. We discuss implications of these

  19. Attracting STEM talent: do STEM students prefer traditional or work/life-interaction labs?

    Science.gov (United States)

    DeFraine, William C; Williams, Wendy M; Ceci, Stephen J

    2014-01-01

    The demand for employees trained in science, technology, engineering, and mathematics (STEM) fields continues to increase, yet the number of Millennial students pursuing STEM is not keeping pace. We evaluated whether this shortfall is associated with Millennials' preference for flexibility and work/life-interaction in their careers-a preference that may be inconsistent with the traditional idea of a science career endorsed by many lab directors. Two contrasting approaches to running STEM labs and training students were explored, and we created a lab recruitment video depicting each. The work-focused video emphasized the traditional notions of a science lab, characterized by long work hours and a focus on individual achievement and conducting research above all else. In contrast, the work/life-interaction-focused video emphasized a more progressive view - lack of demarcation between work and non-work lives, flexible hours, and group achievement. In Study 1, 40 professors rated the videos, and the results confirmed that the two lab types reflected meaningful real-world differences in training approaches. In Study 2, we recruited 53 current and prospective graduate students in STEM fields who displayed high math-identification and a commitment to science careers. In a between-subjects design, they watched one of the two lab-recruitment videos, and then reported their anticipated sense of belonging to and desire to participate in the lab depicted in the video. Very large effects were observed on both primary measures: Participants who watched the work/life-interaction-focused video reported a greater sense of belonging to (d = 1.49) and desire to participate in (d = 1.33) the lab, relative to participants who watched the work-focused video. These results suggest Millennials possess a strong desire for work/life-interaction, which runs counter to the traditional lab-training model endorsed by many lab directors. We discuss implications of these findings for STEM

  20. Beauty is more attractive: particle production and moduli trapping with higher dimensional interaction

    International Nuclear Information System (INIS)

    We study quantum effects on moduli dynamics arising from particle production near the enhanced symmetry point (ESP). We focus on non-renormalizable couplings between the moduli field and the field that becomes light at the ESP. Considering higher dimensional interaction, we find that particle production is significant in a large area, which is even larger than the area that is expected from a renormalizable interaction. It is possible to find this possibility from a trivial adiabatic condition; however the quantitative estimation of particle production and trapping of the field in motion are far from trivial. In this paper we study particle production and trapping in detail, using both the analytical and numerical calculations, to find a clear and intuitive result that supports trapping in a vast variety of theories. Our study shows that trapping driven by a non-renormalizable interaction is possible. This possibility has not been considered in previous works. Some phenomenological models of particle physics will be mentioned to complement discussion

  1. Beauty is more attractive: particle production andmoduli trapping with higher dimensional interaction

    Science.gov (United States)

    Enomoto, Seishi; Iida, Satoshi; Maekawa, Nobuhiro; Matsuda, Tomohiro

    2014-01-01

    We study quantum effects on moduli dynamics arising from particle production near the enhanced symmetry point (ESP). We focus on non-renormalizable couplings between the moduli field and the field that becomes light at the ESP. Considering higher dimensional interaction, we find that particle production is significant in a large area, which is even larger than the area that is expected from a renormalizable interaction. It is possible to find this possibility from a trivial adiabatic condition; however the quantitative estimation of particle production and trapping of the field in motion are far from trivial. In this paper we study particle production and trapping in detail, using both the analytical and numerical calculations, to find a clear and intuitive result that supports trapping in a vast variety of theories. Our study shows that trapping driven by a non-renormalizable interaction is possible. This possibility has not been considered in previous works. Some phenomenological models of particle physics will be mentioned to complement discussion.

  2. Beauty is more attractive: particle production and moduli trapping with higher dimensional interaction

    Energy Technology Data Exchange (ETDEWEB)

    Enomoto, Seishi [Kobayashi Maskawa Institute, Nagoya University,Nagoya 464-8602 (Japan); Institute of Theoretical Physics, Faculty of Physics,University of Warsaw, Hoa 69, 00-681 Warsaw (Poland); Iida, Satoshi [Department of Physics, Nagoya University,Nagoya 464-8602 (Japan); Maekawa, Nobuhiro [Kobayashi Maskawa Institute, Nagoya University,Nagoya 464-8602 (Japan); Department of Physics, Nagoya University,Nagoya 464-8602 (Japan); Matsuda, Tomohiro [Laboratory of Physics, Saitama Institute of Technology,Saitama 369-0293 (Japan)

    2014-01-24

    We study quantum effects on moduli dynamics arising from particle production near the enhanced symmetry point (ESP). We focus on non-renormalizable couplings between the moduli field and the field that becomes light at the ESP. Considering higher dimensional interaction, we find that particle production is significant in a large area, which is even larger than the area that is expected from a renormalizable interaction. It is possible to find this possibility from a trivial adiabatic condition; however the quantitative estimation of particle production and trapping of the field in motion are far from trivial. In this paper we study particle production and trapping in detail, using both the analytical and numerical calculations, to find a clear and intuitive result that supports trapping in a vast variety of theories. Our study shows that trapping driven by a non-renormalizable interaction is possible. This possibility has not been considered in previous works. Some phenomenological models of particle physics will be mentioned to complement discussion.

  3. Fatal attraction

    DEFF Research Database (Denmark)

    Jensen, Kim Ebensgaard

    2012-01-01

    of the use of the Danish ihjel-construction which accounts for patterns of attraction of construction-verb attraction, patterns of productivity, and various types of subconstructions, including item- and item-class-based ones and metaphorical extensions. The description of the ihjel...

  4. Thin Filament Structure and the Steric Blocking Model.

    Science.gov (United States)

    Lehman, William

    2016-04-01

    By interacting with the troponin-tropomyosin complex on myofibrillar thin filaments, Ca2+ and myosin govern the regulatory switching processes influencing contractile activity of mammalian cardiac and skeletal muscles. A possible explanation of the roles played by Ca2+ and myosin emerged in the early 1970s when a compelling "steric model" began to gain traction as a likely mechanism accounting for muscle regulation. In its most simple form, the model holds that, under the control of Ca2+ binding to troponin and myosin binding to actin, tropomyosin strands running along thin filaments either block myosin-binding sites on actin when muscles are relaxed or move away from them when muscles are activated. Evidence for the steric model was initially based on interpretation of subtle changes observed in X-ray fiber diffraction patterns of intact skeletal muscle preparations. Over the past 25 years, electron microscopy coupled with three-dimensional reconstruction directly resolved thin filament organization under many experimental conditions and at increasingly higher resolution. At low-Ca2+, tropomyosin was shown to occupy a "blocked-state" position on the filament, and switched-on in a two-step process, involving first a movement of tropomyosin away from the majority of the myosin-binding site as Ca2+ binds to troponin and then a further movement to fully expose the site when small numbers of myosin heads bind to actin. In this contribution, basic information on Ca2+-regulation of muscle contraction is provided. A description is then given relating the voyage of discovery taken to arrive at the present understanding of the steric regulatory model. PMID:27065174

  5. Steric-electronic effects in malarial peptides inducing sterile immunity

    Energy Technology Data Exchange (ETDEWEB)

    Moreno-Vranich, Armando [Fundacion Instituto de Inmunologia de Colombia (FIDIC), Bogota (Colombia); Patarroyo, Manuel E., E-mail: mepatarr@mail.com [Fundacion Instituto de Inmunologia de Colombia (FIDIC), Bogota (Colombia); Universidad Nacional de Colombia, Bogota (Colombia)

    2012-07-13

    Highlights: Black-Right-Pointing-Pointer Is it evident that the residues position are relevant regarding of {phi} angular value. Black-Right-Pointing-Pointer The geometry considered for detailing the alterations undergone by HABPs. Black-Right-Pointing-Pointer The inter planar interactions ruled by clashes between the atoms making them up. -- Abstract: Conserved Plasmodium falciparum high activity binding peptides' (HABPs) most relevant proteins involved in malaria parasite invasion are immunologically silent; critical binding residues must therefore be specifically replaced to render them highly immunogenic and protection-inducing. Such changes have a tremendous impact on these peptides' steric-electronic effects, such as modifications to peptide length peptide bonds and electronic orbitals' disposition, to allow a better fit into immune system MHCII molecules and better interaction with the TCR which might account for the final immunological outcome.

  6. Steric effects induce geometric remodeling of actin bundles in filopodia

    CERN Document Server

    Dobramysl, Ulrich; Erban, Radek

    2016-01-01

    Filopodia are ubiquitous fingerlike protrusions, spawned by many eukaryotic cells, to probe and interact with their environments. Polymerization dynamics of actin filaments, comprising the structural core of filopodia, largely determine their instantaneous lengths and overall lifetimes. The polymerization reactions at the filopodial tip require transport of G-actin, which enter the filopodial tube from the filopodial base and diffuse toward the filament barbed ends near the tip. Actin filaments are mechanically coupled into a tight bundle by cross-linker proteins. Interestingly, many of these proteins are relatively short, restricting the free diffusion of cytosolic G-actin throughout the bundle and, in particular, its penetration into the bundle core. To investigate the effect of steric restrictions on G-actin diffusion by the porous structure of filopodial actin filament bundle, we used a particle-based stochastic simulation approach. We discovered that excluded volume interactions result in partial and the...

  7. Physical forces between humans and how humans attract and repel each other based on their social interactions in an online world

    CERN Document Server

    Thurner, Stefan

    2014-01-01

    Physical interactions between particles are the result of the exchange of gauge bosons. Human interactions are mediated by the exchange of messages, goods, money, promises, hostilities, etc. While in the physical world interactions and their associated forces have immediate dynamical consequences (Newton's law) the situation is not clear for human interactions. Here we study the acceleration between humans who interact through the exchange of messages, goods and hostilities in a massive multiplayer online game. For this game we have complete information about all interactions (exchange events) between about 1/2 million players, and about their trajectories (positions) in a metric space of the game universe at any point in time. We derive the interaction potentials for communication, trade and attacks and show that they are harmonic in nature. Individuals who exchange messages and trade goods generally attract each other and start to separate immediately after exchange events stop. The interaction potential fo...

  8. The interfacial properties of the peptide Polybia-MP1 and its interaction with DPPC are modulated by lateral electrostatic attractions.

    Science.gov (United States)

    Alvares, Dayane S; Fanani, Maria Laura; Ruggiero Neto, João; Wilke, Natalia

    2016-02-01

    Polybia-MP1 (IDWKKLLDAAKQIL-NH2), extracted from the Brazilian wasp Polybia paulista, exhibits a broad-spectrum bactericidal activity without being hemolytic and cytotoxic. In the present study, we analyzed the surface properties of the peptide and its interaction with DPPC in Langmuir monolayers. Polybia-MP1 formed stable monolayers, with lateral areas and surface potential values suggesting a mostly α-helical structure oriented near perpendicular to the membrane plane. In DPPC-peptide mixed monolayers, MP1 co-crystallized with the lipid forming branched domains only when the subphase was pure water. On subphases with high salt concentrations or at acidic or basic conditions, the peptide formed less densely packed films and was excluded from the domains, indicating the presence of attractive electrostatic interactions between peptides, which allow them to get closer to each other and to interact with DPPC probably as a consequence of a particular peptide arrangement. The residues responsible of the peptide-peptide attraction are suggested to be the anionic aspartic acids and the cationic lysines, which form a salt bridge, leading to oriented interactions in the crystal and thereby to branched domains. For this peptide, the balance between total attractive and repulsive interactions may be finely tuned by the aqueous ionic strength and pH, and since this effect is related with lysines and aspartic acids, similar effects may also occur in other peptides containing these residues in their sequences. PMID:26673092

  9. Fatal attraction

    DEFF Research Database (Denmark)

    Jensen, Kim Ebensgaard

    2012-01-01

    The purpose of this paper is two-fold. Firstly, it presents an argument for usage-based inheritance models over complete inheritance models in construction grammar. It is argued that, with the principle of inductive language learning as their foundation, usage-based inheritance models allow for...... redundancies and incongruities in construction networks which enables linguists to take into account details of language use, which would otherwise not be facilitated in complete inheritance models. Secondly, making use of the method of collostructional analysis, the article offers a corpus-based description...... of the use of the Danish ihjel-construction which accounts for patterns of attraction of construction-verb attraction, patterns of productivity, and various types of subconstructions, including item- and item-class-based ones and metaphorical extensions. The description of the ihjel...

  10. Zero Steric Potential and bond order

    Science.gov (United States)

    Ghasemi, S.; Noorizadeh, S.

    2016-05-01

    The variation of Zero Steric Potential (ZSP) through a C-C bond shows two maximums, which their values depend on the bond order (BO). A good relationship (R2 = 1) is observed between the mean values of maximum ZSPs and the bond orders of C-C bonds in ethane, ethylene and acetylene, as reference molecules (Ln BO = 1.956ZSP‾max - 0.898). The obtained equation is used to predict the C-C bond orders of more than twenty aromatic and aliphatic hydrocarbons. The results show that the obtained bond orders from ZSP‾max are more reliable than those which are evaluated using NBO and Laplacian methods.

  11. Acoustic Attraction

    Science.gov (United States)

    Oviatt, Eric; Patsiaouris, Konstantinos; Denardo, Bruce

    2009-11-01

    A sound source of finite size produces a diverging traveling wave in an unbounded fluid. A rigid body that is small compared to the wavelength experiences an attractive radiation force (toward the source). An attractive force is also exerted on the fluid itself. The effect can be demonstrated with a styrofoam ball suspended near a loudspeaker that is producing sound of high amplitude and low frequency (for example, 100 Hz). The behavior can be understood and roughly calculated as a time-averaged Bernoulli effect. A rigorous scattering calculation yields a radiation force that is within a factor of two of the Bernoulli result. For a spherical wave, the force decreases as the inverse fifth power of the distance from the source. Applications of the phenomenon include ultrasonic filtration of liquids and the growth of supermassive black holes that emit sound waves in a surrounding plasma. An experiment is being conducted in an anechoic chamber with a 1-inch diameter aluminum ball that is suspended from an analytical balance. Directly below the ball is a baffled loudspeaker that exerts an attractive force that is measured by the balance.

  12. Judging attractiveness: Biases due to raters’ own attractiveness and intelligence

    OpenAIRE

    Stacy Yen-Lin Sim; Jenna Saperia; Jill Anne Brown; Frank John Bernieri

    2015-01-01

    Tennis and Dabbs (1975) reported that physically attractive males showed a positivity bias when rating the attractiveness of others. The opposite pattern was observed for females. We attempted to replicate and extend these findings by: (1) using self-assessed attractiveness rather than the experimentally derived attractiveness measure used in previous research, (2) using face-to-face interactions with targets as opposed to using photographs, and (3) examining the effect of another ego-involvi...

  13. Electron-electron attractive interaction in Maxwell-Chern-Simons QED{sub 3} at zero temperature

    Energy Technology Data Exchange (ETDEWEB)

    Belich, H.; Ferreira Junior, M.M.; Helayel-Neto, J.A. [Centro Brasileiro de Pesquisas Fisicas (CBPF), Rio de Janeiro, RJ (Brazil). E-mail: belich@cbpf.br; manojr@cbpf.br; helayel@gft.ucp.br; Ferreira Junior, M.M. [Universidade Catolica de Petropolis, RJ (Brazil). Grupo de Fisica Teorica. E-mail: delcima@gft.ucp.br

    2001-04-01

    One discusses the issue of low-energy electron-electron bound states in the Maxwell-Chern-Simons model coupled to QED{sub 3} with spontaneous breaking of a local U(1)-symmetry. The scattering potential, in the non-relativistic limit, steaming from the electron-electron Moeller scattering, mediated by the Maxwell-Chern-Simons-Proca gauge field and the Higgs scalar, might be attractive by fine-tuning properly the physical parameters of the model. (author)

  14. Effective interactions between fluid membranes

    Science.gov (United States)

    Lu, Bing-Sui; Podgornik, Rudolf

    2015-08-01

    A self-consistent theory is proposed for the general problem of interacting undulating fluid membranes subject to the constraint that they do not interpenetrate. We implement the steric constraint via an exact functional integral representation and, through the use of a saddle-point approximation, transform it into a novel effective steric potential. The steric potential is found to consist of two contributions: one generated by zero-mode fluctuations of the membranes and the other by thermal bending fluctuations. For membranes of cross-sectional area S , we find that the bending fluctuation part scales with the intermembrane separation d as d-2 for d ≪√{S } but crosses over to d-4 scaling for d ≫√{S } , whereas the zero-mode part of the steric potential always scales as d-2. For membranes interacting exclusively via the steric potential, we obtain closed-form expressions for the effective interaction potential and for the rms undulation amplitude σ , which becomes small at low temperatures T and/or large bending stiffnesses κ . Moreover, σ scales as d for d ≪√{S } but saturates at √{kBT S /κ } for d ≫√{S } . In addition, using variational Gaussian theory, we apply our self-consistent treatment to study intermembrane interactions subject to different types of potentials: (i) the Moreira-Netz potential for a pair of strongly charged membranes with an intervening solution of multivalent counterions, (ii) an attractive square well, (iii) the Morse potential, and (iv) a combination of hydration and van der Waals interactions.

  15. Switching between attractive and repulsive Coulomb-interaction-mediated drag in an ambipolar GaAs/AlGaAs bilayer device

    International Nuclear Information System (INIS)

    We present measurements of Coulomb drag in an ambipolar GaAs/AlGaAs double quantum well structure that can be configured as both an electron-hole bilayer and a hole-hole bilayer, with an insulating barrier of only 10 nm between the two quantum wells. Coulomb drag resistivity is a direct measure of the strength of interlayer particle-particle interactions. We explore the strongly interacting regime of low carrier densities (2D interaction parameter rs up to 14). Our ambipolar device design allows a comparison between the effects of the attractive electron-hole and repulsive hole-hole interactions and also shows the effects of the different effective masses of electrons and holes in GaAs

  16. Switching between attractive and repulsive Coulomb-interaction-mediated drag in an ambipolar GaAs/AlGaAs bilayer device

    Energy Technology Data Exchange (ETDEWEB)

    Zheng, B.; Croxall, A. F.; Waldie, J., E-mail: jw353@cam.ac.uk; Sfigakis, F.; Farrer, I.; Beere, H. E.; Ritchie, D. A. [Cavendish Laboratory, University of Cambridge, J.J. Thomson Avenue, Cambridge CB3 0HE (United Kingdom); Das Gupta, K. [Cavendish Laboratory, University of Cambridge, J.J. Thomson Avenue, Cambridge CB3 0HE (United Kingdom); Department of Physics, Indian Institute of Technology Bombay, Mumbai 400076 (India)

    2016-02-08

    We present measurements of Coulomb drag in an ambipolar GaAs/AlGaAs double quantum well structure that can be configured as both an electron-hole bilayer and a hole-hole bilayer, with an insulating barrier of only 10 nm between the two quantum wells. Coulomb drag resistivity is a direct measure of the strength of interlayer particle-particle interactions. We explore the strongly interacting regime of low carrier densities (2D interaction parameter r{sub s} up to 14). Our ambipolar device design allows a comparison between the effects of the attractive electron-hole and repulsive hole-hole interactions and also shows the effects of the different effective masses of electrons and holes in GaAs.

  17. Particle attraction effects on the centrifugal casting and extrusion of alumina

    International Nuclear Information System (INIS)

    Interparticle attraction forces were empirically related to the centrifugal casting and extrusion behavior of flocculated alumina suspensions. Attractive forces were altered by two approaches: Salt flocculation, which entails regulating the electrical double-layer thickness through electrolyte additions; and screening of van der Waals attraction by steric interactions of surface-adsorbed fatty acids. Specimens produced by both compressibility at a critical maximum density that increased with decreasing interparticle attraction. Gradients in packing density during centrifugal casting were alleviated using both methods as long as spatial variations of the effective stress were within the low-compressibility range. We hypothesized that the reduced interparticle attraction in both methods may also raise the threshold packing density at which ductile-to-brittle transitions occur during plastic shear. Specimens prepared with oleic acid adlayers were highly plastic and easily extrudable at solids contents of up to 59 vol%, although salt-flocculated samples at 55 vol% density extruded at creeping flow rates that were insensitive to the applied pressure. Results suggested that particle rearrangement during shear, is a rate-limiting process, with an average relaxation time that is lowered by reducing interparticle attraction

  18. Physical Forces between Humans and How Humans Attract and Repel Each Other Based on Their Social Interactions in an Online World.

    Directory of Open Access Journals (Sweden)

    Stefan Thurner

    Full Text Available Physical interactions between particles are the result of the exchange of gauge bosons. Human interactions are mediated by the exchange of messages, goods, money, promises, hostilities, etc. While in the physical world interactions and their associated forces have immediate dynamical consequences (Newton's laws the situation is not clear for human interactions. Here we quantify the relative acceleration between humans who interact through the exchange of messages, goods and hostilities in a massive multiplayer online game. For this game we have complete information about all interactions (exchange events between about 430,000 players, and about their trajectories (movements in the metric space of the game universe at any point in time. We use this information to derive "interaction potentials" for communication, trade and attacks and show that they are harmonic in nature. Individuals who exchange messages and trade goods generally attract each other and start to separate immediately after exchange events end. The form of the interaction potential for attacks mirrors the usual "hit-and-run" tactics of aggressive players. By measuring interaction intensities as a function of distance, velocity and acceleration, we show that "forces" between players are directly related to the number of exchange events. We find an approximate power-law decay of the likelihood for interactions as a function of distance, which is in accordance with previous real world empirical work. We show that the obtained potentials can be understood with a simple model assuming an exchange-driven force in combination with a distance-dependent exchange rate.

  19. Physical Forces between Humans and How Humans Attract and Repel Each Other Based on Their Social Interactions in an Online World

    Science.gov (United States)

    Thurner, Stefan; Fuchs, Benedikt

    2015-01-01

    Physical interactions between particles are the result of the exchange of gauge bosons. Human interactions are mediated by the exchange of messages, goods, money, promises, hostilities, etc. While in the physical world interactions and their associated forces have immediate dynamical consequences (Newton’s laws) the situation is not clear for human interactions. Here we quantify the relative acceleration between humans who interact through the exchange of messages, goods and hostilities in a massive multiplayer online game. For this game we have complete information about all interactions (exchange events) between about 430,000 players, and about their trajectories (movements) in the metric space of the game universe at any point in time. We use this information to derive “interaction potentials" for communication, trade and attacks and show that they are harmonic in nature. Individuals who exchange messages and trade goods generally attract each other and start to separate immediately after exchange events end. The form of the interaction potential for attacks mirrors the usual “hit-and-run" tactics of aggressive players. By measuring interaction intensities as a function of distance, velocity and acceleration, we show that “forces" between players are directly related to the number of exchange events. We find an approximate power-law decay of the likelihood for interactions as a function of distance, which is in accordance with previous real world empirical work. We show that the obtained potentials can be understood with a simple model assuming an exchange-driven force in combination with a distance-dependent exchange rate. PMID:26196505

  20. Azide Binding Controlled by Steric Interactions in Second Sphere. Synthesis, Crystal Structure, and Magnetic Properties of [Ni(II)2(L)(μ1,1-N3)][ClO4] (L = Macrocyclic N6S2 Ligand).

    Science.gov (United States)

    Jeremies, Alexander; Gruschinski, Sina; Meyer, Michel; Matulis, Vitaly; Ivashkevich, Oleg A; Kobalz, Karolin; Kersting, Berthold

    2016-02-15

    The dinuclear Ni(II) complex [Ni2(L(2))][ClO4]2 (3) supported by the 28-membered hexaaza-dithiophenolate macrocycle (L(2))(2-) binds the N3(-) ion specifically end-on yielding [Ni2(L(2))(μ1,1-N3)][ClO4] (7) or [Ni2(L(2))(μ1,1-N3)][BPh4] (8), while the previously reported complex [Ni2L(1)(μ1,3-N3)][ClO4] (2) of the 24-membered macrocycle (L(1))(2-) coordinates it in the end-to-end fashion. A comparison of the X-ray structures of 2, 3, and 7 reveals the form-selective binding of complex 3 to be a consequence of its preorganized, channel-like binding pocket, which accommodates the azide anion via repulsive CH···π interactions in the end-on mode. In contrast to [Ni2L(1)(μ1,3-N3)][ClO4] (2), which features a S = 0 ground state, [Ni2(L(2))(μ1,1-N3)][BPh4] (8) has a S = 2 ground state that is attained by competing antiferromagnetic and ferromagnetic exchange interactions via the thiolato and azido bridges with a value for the magnetic exchange coupling constant J of 13 cm(-1) (H = -2JS1S2). These results are further substantiated by density functional theory calculations. The stability of the azido-bridged complex determined by isothermal titration calorimetry in MeCN/MeOH 1/1 v/v (log K11 = 4.88(4) at I = 0.1 M) lies in between those of the fluorido- (log K11 = 6.84(7)) and chlorido-bridged complexes (log K11 = 3.52(5)). These values were found to compare favorably well with the equilibrium constants derived at lower ionic strength (I = 0.01 M) by absorption spectrophotometry (log K11 = 5.20(1), 7.77(9), and 4.13(3) for N3(-), F(-), and Cl(-) respectively). PMID:26836637

  1. Attractive halogen-halogen interactions: F3CCl...FH and F3CCl...FCH3 dimers

    International Nuclear Information System (INIS)

    The F3CCl...FH and F3CCl...FCH3 dimers, which feature the halogen-halogen contacts, are investigated at MP2/6-311++G(d,p) and MP2/aug-cc-pVDZ levels of approximation. The binding energies of these complexes are found to be comparable to those of the weak hydrogen bonds. In both complexes the Cl...F are found to be significantly shorter than the sum of the corresponding van der Waals radii. The C-Cl...F contacts are also found to exhibit certain deviation from linearity. However, the energy differences between linear and bent structures are very small and primarily accounted for by electrostatic interactions between remote parts of the dimer. This indicates a high conformational flexibility of the halogen-halogen contacts and may help to explain the diversity of structural features in crystals formed by halogen-containing molecules. In both dimers the halogen-halogen interaction leads to certain shortening of the C-Cl electron accepting bond. This is accompanied by a small increase of the C-Cl stretching frequency. Hence, the two investigated dimers can possibly be classified as the blue-shifting halogen-halogen contacts

  2. Physical Attractiveness and Counseling Skills.

    Science.gov (United States)

    Vargas, Alice M.; Borkowski, John G.

    1982-01-01

    Searched for interaction between quality of counseling skills (presence or absence of empathy, genuineness, and positive regard) and physical attractiveness as determinants of counseling effectiveness. Attractiveness influenced perceived effectiveness of counselor's skill. Analyses of expectancy data revealed that only with good skills did…

  3. From information theory to quantitative description of steric effects.

    Science.gov (United States)

    Alipour, Mojtaba; Safari, Zahra

    2016-07-21

    Immense efforts have been made in the literature to apply the information theory descriptors for investigating the electronic structure theory of various systems. In the present study, the information theoretic quantities, such as Fisher information, Shannon entropy, Onicescu information energy, and Ghosh-Berkowitz-Parr entropy, have been used to present a quantitative description for one of the most widely used concepts in chemistry, namely the steric effects. Taking the experimental steric scales for the different compounds as benchmark sets, there are reasonable linear relationships between the experimental scales of the steric effects and theoretical values of steric energies calculated from information theory functionals. Perusing the results obtained from the information theoretic quantities with the two representations of electron density and shape function, the Shannon entropy has the best performance for the purpose. On the one hand, the usefulness of considering the contributions of functional groups steric energies and geometries, and on the other hand, dissecting the effects of both global and local information measures simultaneously have also been explored. Furthermore, the utility of the information functionals for the description of steric effects in several chemical transformations, such as electrophilic and nucleophilic reactions and host-guest chemistry, has been analyzed. The functionals of information theory correlate remarkably with the stability of systems and experimental scales. Overall, these findings show that the information theoretic quantities can be introduced as quantitative measures of steric effects and provide further evidences of the quality of information theory toward helping theoreticians and experimentalists to interpret different problems in real systems. PMID:27321125

  4. Adsorption, Desorption, Surface Diffusion, Lattice Defect Formation, and Kink Incorporation Processes of Particles on Growth Interfaces of Colloidal Crystals with Attractive Interactions

    Directory of Open Access Journals (Sweden)

    Yoshihisa Suzuki

    2016-07-01

    Full Text Available Good model systems are required in order to understand crystal growth processes because, in many cases, precise incorporation processes of atoms or molecules cannot be visualized easily at the atomic or molecular level. Using a transmission-type optical microscope, we have successfully observed in situ adsorption, desorption, surface diffusion, lattice defect formation, and kink incorporation of particles on growth interfaces of colloidal crystals of polystyrene particles in aqueous sodium polyacrylate solutions. Precise surface transportation and kink incorporation processes of the particles into the colloidal crystals with attractive interactions were observed in situ at the particle level. In particular, contrary to the conventional expectations, the diffusion of particles along steps around a two-dimensional island of the growth interface was not the main route for kink incorporation. This is probably due to the number of bonds between adsorbed particles and particles in a crystal; the number exceeds the limit at which a particle easily exchanges its position to the adjacent one along the step. We also found novel desorption processes of particles from steps to terraces, attributing them to the assistance of attractive forces from additionally adsorbing particles to the particles on the steps.

  5. Estimating the magnitude of steric effects in rigid systems by NMR

    Energy Technology Data Exchange (ETDEWEB)

    Yoneda, Julliane Diniz [Universidade Federal Fluminense (UFF), Niteroi, RJ (Brazil). Programa Pos-Graduacao em Quimica Organica; Seidl, Peter Rudolf [Universidade Federal do Rio de Janeiro (UFRJ), RJ (Brazil). Escola de Quimica; Leal, Katia Zaccur, E-mail: pseidl@eq.ufrj.br [Universidade Federal Fluminense (UFF), Niteroi, RJ (Brazil). Dept. de Fisico-Quimica. Programa de Pos-Graduacao em Quimica Organica

    2008-07-01

    The rapid advance of supramolecular chemistry has led to a better understanding of the forces and interactions that are responsible for many different phenomena. Among these, steric effects play an important role in determining the constraints to association between the species involved. Although the role of steric effects has been recognized for a long time, quantitative information has been mainly related to the comparison of these effects on a chemical reaction or conformational equilibrium rather than the properties of the group of atoms that is responsible for their manifestation. This situation has been changing with the increase in power of computational methods and the accumulation of data on model compounds that can be used for the purpose of comparison. Here we present a short review of our recent work on NMR of rigid carbocyclic systems and apply this type of approach to di- and triamantane systems. Our results show how NMR can be used to locate the segment of a molecule that is subjected to steric effects and evaluate the degree to which these effects will distort its geometry. (author)

  6. Judging attractiveness: Biases due to raters’ own attractiveness and intelligence

    Directory of Open Access Journals (Sweden)

    Stacy Yen-Lin Sim

    2015-12-01

    Full Text Available Tennis and Dabbs (1975 reported that physically attractive males showed a positivity bias when rating the attractiveness of others. The opposite pattern was observed for females. We attempted to replicate and extend these findings by: (1 using self-assessed attractiveness rather than the experimentally derived attractiveness measure used in previous research, (2 using face-to-face interactions with targets as opposed to using photographs, and (3 examining the effect of another ego-involving attribute: intelligence. Consistent with previous research, attractiveness judgments made by men, but not women, correlated positively with their own self-perceived level of attractiveness (r = .51, p < .001. Attractiveness judgments made by women, but not men, correlated negatively with their intelligence (r = −.32, p = .001. Judgments of attractiveness are thus biased by a rater’s own attributes (e.g. attractiveness and intelligence, but these effects are not generalizable across men and women raters, and may be driven by different mechanisms.

  7. Steric Maps to Evaluate the Role of Steric Hindrance on the IPr NHC Ligand

    KAUST Repository

    Poater, Albert

    2013-06-01

    Density functional theory (DFT) calculations were used to predict and rationalize the effect of the modification of the structure of the prototype 1,3-bis(2,6-diisopropylphenyl)imidazol-2-ylidene) (IPr) N-heterocyclic carbene (NHC) ligand. The modification consists in the substitution of the methyl groups of ortho isopropyl substituent with phenyl groups, and here we plan to describe how such significant changes effect the metal environment and therefore the related catalytic behaviour by simple steric maps. Bearing in mind that there is a significant structural difference between IPr and IPr* ligands, that translated in different reactivity for several olefin metathesis reactions, here by means of DFT we characterize where the NHC ligand plays a more active role and where it is a simple spectator, or at least its modification does not significantly change its catalytic role/performance. Furthermore, this communication endeavours to modify further the skeleton of the IPr NHC ligand. The optimization of these bulky new systems go to the limits of the DFT computational method.

  8. Seasonal Change of Steric Sea Level in the GIN Seas

    Institute of Scientific and Technical Information of China (English)

    LI Lei; WANG Huijuan; SUN Ruili

    2011-01-01

    The Greenland Sea, Iceland Sea, and Norwegian Sea (GIN seas) form the main channel connecting the Arctic Ocean with other Oceans, where significant water and energy exchange take place, and play an important role in global climate change. In this study steric sea level, associated with temperature and salinity, in the GIN seas is examined based on analysis of the monthly temperature and salinity fields from Polar science center Hydrographic Climatology (PHC3.0). A method proposed by Tabata et al. is used to calculate steric sea level, in which, steric sea level change due to thermal expansion and haline contraction is termed as the thermosteric component (TC) and the halosteric component (SC), recpectively. Total steric sea level (TSSL) change is the sum of TC and SC. The study shows that SC is making more contributions than TC to the seasonal change of TSSL in the Greenland Sea, whereas TC contributes more in the Norwegian and the Iceland Seas. Annual variation of TSSL is larger than 50ram over most regions of the GIN Seas, and can be larger than 200mm at some locations such as 308mm at 76.5°N, 12.5°E and 246mm at 77.50N, 17.5°W.

  9. Sterically encumbered tin and phosphorus peri-substituted acenaphthenes.

    Science.gov (United States)

    Chalmers, Brian A; Athukorala Arachchige, Kasun S; Prentis, Joanna K D; Knight, Fergus R; Kilian, Petr; Slawin, Alexandra M Z; Woollins, J Derek

    2014-08-18

    A group of sterically encumbered peri-substituted acenaphthenes have been prepared, containing tin moieties at the 5,6-positions in 1-3 ([Acenap(SnR3)2], Acenap = acenaphthene-5,6-diyl; R3 = Ph3 (1), Me3 (2); [(Acenap)2(SnMe2)2] (3)) and phosphorus functional groups at the proximal peri-positions in 4 and 5 ([Acenap(PR2)(P(i)Pr2)] R2 = Ph2 (4), Ph((i)Pr) (5)). Bis(stannane) structures 1-3 are dominated by repulsive interactions between the bulky tin groups, leading to peri-distances approaching the sum of van der Waals radii. Conversely, the quasi-linear CPh-P···P three-body fragments found in bis(phosphine) 4 suggest the presence of a lp(P)-σ*(P-C) donor-acceptor 3c-4e type interaction, supported by a notably short intramolecular P···P distance and notably large JPP through-space coupling (180 Hz). Severely strained bis(sulfides) 4-S and 5-S, experiencing pronounced in-plane and out-of-plane displacements of the exocyclic peri-bonds, have also been isolated following treatment of 4 and 5 with sulfur. The resulting nonbonded intramolecular P···P distances, ∼4.05 Å and ∼12% longer than twice the van der Waals radii of P (3.60 Å), are among the largest ever reported peri-separations, independent of the heteroatoms involved, and comparable to the distance found in 1 containing the larger Sn atoms (4.07 Å). In addition we report two metal complexes with square planar [(4)PtCl2] (4-Pt) and octahedral cis-[(4)Mo(CO)4] (4-Mo) geometries. In both complexes the bis(phosphine) backbone is distorted, but notably less so than in bis(sulfide) 4-S. All compounds were fully characterized, and except for bis(phosphine) 5, crystal structures were determined. PMID:25080308

  10. Viscoelastic properties of sterically stabilised emulsions and their stability.

    Science.gov (United States)

    Tadros, Tharwat

    2015-08-01

    The interaction forces between emulsion droplets containing adsorbed polymeric surfactants and the theory of steric stabilisation are briefly described. The results for the viscoelastic properties of O/W emulsions that are stabilised with partially hydrolysed poly(vinyl acetate) that is commonly referred to as poly(vinyl alcohol) (PVA) with 4% vinyl acetate are given. The effect of the oil volume fraction, addition of electrolytes and increasing temperature is described. This allows one to obtain various parameters such as the adsorbed layer thickness, the critical flocculation concentration of electrolyte (CFC) and critical flocculation temperature (CFT) at constant electrolyte concentration. The viscoelastic properties of O/W emulsions stabilised with an A-B-A block copolymer of polyethylene oxide (A) and polypropylene oxide (B) are described. These emulsions behave as viscoelastic liquids showing a cross-over-point between G' (the elastic component of the complex modulus) and G″ (the viscous component of the complex modulus) at a characteristic frequency. Plots of G' and G″ versus oil volume fraction ϕ show the transition from predominantly viscous to predominantly elastic response at a critical volume fraction ϕ(c). The latter can be used to estimate the adsorbed layer thickness of the polymeric surfactants. Results are also shown for W/O emulsions stabilised with an A-B-A block copolymer of polyhydroxystearic acid (PHS, A) and polyethylene oxide (PEO, B). The viscosity volume fraction curves could be fitted to the Dougherty-Krieger equation for hard-spheres. The results could be applied to give an estimate of the adsorbed layer thickness Δ which shows a decrease with increase of the water volume fraction. This is due to the interpenetration and/or compression of the PHS layers on close approach of the water droplets on increasing the water volume fraction. The last section of the review gives an example of O/W emulsion stability using an AB(n) graft

  11. Steric stabilization of nanoparticles with grafted low molecular weight ligands in highly concentrated brines including divalent ions.

    Science.gov (United States)

    Worthen, Andrew J; Tran, Vu; Cornell, Kevin A; Truskett, Thomas M; Johnston, Keith P

    2016-02-21

    Whereas numerous studies of stabilization of nanoparticles (NPs) in electrolytes have examined biological fluids, the interest has grown recently in media with much higher ionic strengths including seawater and brines relevant to environmental science and subsurface oil and gas reservoirs. Given that electrostatic repulsion is limited at extremely high ionic strengths due to charge screening, we have identified ligands that are well solvated in concentrated brine containing divalent cations and thus provide steric stabilization of silica nanoparticles. Specifically, the hydrodynamic diameter of silica nanoparticles with grafted low molecular weight ligands, a diol ether, [3-(2,3-dihydroxypropoxy)propyl]-trimethoxysilane, and a zwitterionic sulfobetaine, 3-([dimethyl(3-trimethoxysilyl)propyl]ammonio)propane-1-sulfonate, is shown with dynamic light scattering to remain essentially constant, indicating lack of aggregation, at room temperature and up to 80 °C for over 30 days. An extended DLVO model signifies that steric stabilization is strongly dominant against van der Waals attraction for ∼10 nm particles given that these ligands are well solvated even in highly concentrated brine. In contrast, polyethylene glycol oligomers do not provide steric stabilization at elevated temperatures, even at conditions where the ligands are soluble, indicating complicating factors including bridging of the ether oxygens by divalent cations. PMID:26758382

  12. Effects of student physical attractiveness

    Directory of Open Access Journals (Sweden)

    Krnjajić Stevan B.

    2005-01-01

    Full Text Available Implicit personality theories suggest that people draw conclusions about other persons by using a relatively small number of visible features. The formation of "the first impression" is influenced by the factors, such as sex, age, appearances, race or nationality. Frequently, conclusions based on those factors lead to developing social stereotypes. Attractiveness is a good example of "the first impression" effect, because physical attractiveness entails the creation of impression about another person along a relatively great number of dimensions. Experimental paradigm, introduced in the sphere of interpersonal perception around the mid-20th century, led to a relatively great number of studies on stereotype based on physical attractiveness. One of the most often quoted conclusions of studies on physical attractiveness is summarized by the idiom "what is beautiful is good". For example, socially desirable personality traits (responsibility kindness, energy quality, modesty, more successful private and professional life, are all attributed to physically attractive persons. In addition physical attractiveness is coupled with positive expectations, peer acceptance, academic achievement etc. On the basis of studies on the "what is beautiful is good" stereotype, we have situated our analysis within the domain of roles regulating social interaction between teachers and students i.e. effects of physical attractiveness on teacher expectations, peer acceptance and academic achievement.

  13. Physical Distance and Attraction: An Intensification Effect

    Science.gov (United States)

    Schiffenbauer, Allen; Schiavo, R. Steven

    1976-01-01

    This study was designed to test the effects of both interaction distance and the quality of the interaction upon attraction. The implications of this research for studies concerning crowding is discussed, as are possible explanatory mechanisms. (Editor/RK)

  14. Euclidean gravity attracts

    OpenAIRE

    Bakker MR; Smit, J.

    1993-01-01

    We look at gravitational attraction in simplicial gravity using the dynamical triangulation method. On the dynamical triangulation configurations we measure quenched propagators of a free massive scalar field. The masses measured from these propagators show that gravitational attraction is present.

  15. Luneburg-lens-like universal structural Pauli attraction in nucleus-nucleus interactions: Origin of emergence of cluster structures and nuclear rainbows

    Science.gov (United States)

    Ohkubo, S.

    2016-04-01

    The Pauli exclusion principle plays an important role in many-body fermion systems, preventing them from collapsing by repulsion. For example, the Pauli principle causes a repulsive potential at short distances between two α particles. On the other hand, the existence of nuclear rainbows demonstrates that the internuclear potential is sufficiently attractive in the internal region to cause refraction. The two concepts of repulsion and attraction are seemingly irreconcilable. Contrary to traditional understanding, it is shown that the Pauli principle causes a universal structural Pauli attraction between nuclei rather than a structural repulsive core. Through systematic studies of α +α ,α + 16O, ,α + 40Ca, and 16O + 16O systems, it is shown that the emergence of cluster structures near the threshold energy at low energies and nuclear rainbows at high energies is a direct consequence of the Pauli principle.

  16. Luneburg-lens-like universal structural Pauli attraction in nucleus-nucleus interactions: origin of emergence of cluster structures and nuclear rainbows

    CERN Document Server

    Ohkubo, Shigeo

    2016-01-01

    The Pauli exclusion principle plays an important role in many-body fermion systems preventing them from collapsing by repulsion. For example, the Pauli principle causes a repulsive potential at short distances between two $\\alpha$ particles. On the other hand, the existence of nuclear rainbows demonstrates that the inter-nuclear potential is sufficiently attractive in the internal region to cause refraction. The two concepts of repulsion and attraction are seemingly irreconcilable. Contrary to traditional understanding, it is shown that the Pauli principle causes a {\\it universal structural Pauli attraction} between nuclei rather than a {\\it structural repulsive core}. Through systematic studies of $\\alpha$+$\\alpha$, $\\alpha$+$^{16}$O, $\\alpha$+$^{40}$Ca and $^{16}$O+$^{16}$O systems, it is shown that the emergence of cluster structures near the threshold energy at low energies and nuclear rainbows at high energies is a direct consequence of the Pauli principle.

  17. Cryo-EM reveals the steric zipper structure of a light chain-derived amyloid fibril.

    Science.gov (United States)

    Schmidt, Andreas; Annamalai, Karthikeyan; Schmidt, Matthias; Grigorieff, Nikolaus; Fändrich, Marcus

    2016-05-31

    Amyloid fibrils are proteinaceous aggregates associated with diseases in humans and animals. The fibrils are defined by intermolecular interactions between the fibril-forming polypeptide chains, but it has so far remained difficult to reveal the assembly of the peptide subunits in a full-scale fibril. Using electron cryomicroscopy (cryo-EM), we present a reconstruction of a fibril formed from the pathogenic core of an amyloidogenic immunoglobulin (Ig) light chain. The fibril density shows a lattice-like assembly of face-to-face packed peptide dimers that corresponds to the structure of steric zippers in peptide crystals. Interpretation of the density map with a molecular model enabled us to identify the intermolecular interactions between the peptides and rationalize the hierarchical structure of the fibril based on simple chemical principles. PMID:27185936

  18. Steric trapping reveals a cooperativity network in the intramembrane protease GlpG.

    Science.gov (United States)

    Guo, Ruiqiong; Gaffney, Kristen; Yang, Zhongyu; Kim, Miyeon; Sungsuwan, Suttipun; Huang, Xuefei; Hubbell, Wayne L; Hong, Heedeok

    2016-05-01

    Membrane proteins are assembled through balanced interactions among proteins, lipids and water. Studying their folding while maintaining the native lipid environment is necessary but challenging. Here we present methods for analyzing key elements of membrane protein folding including thermodynamic stability, compactness of the unfolded state and folding cooperativity under native conditions. The methods are based on steric trapping, which couples the unfolding of a doubly biotinylated protein to the binding of monovalent streptavidin (mSA). We further advanced this technology for general application by developing versatile biotin probes possessing spectroscopic reporters that are sensitized by mSA binding or protein unfolding. By applying these methods to the Escherichia coli intramembrane protease GlpG, we elucidated a widely unraveled unfolded state, subglobal unfolding of the region encompassing the active site, and a network of cooperative and localized interactions to maintain stability. These findings provide crucial insights into the folding energy landscape of membrane proteins. PMID:26999782

  19. Chiral assembly of weakly curled hard rods: Effect of steric chirality and polarity

    Energy Technology Data Exchange (ETDEWEB)

    Wensink, H. H., E-mail: wensink@lps.u-psud.fr; Morales-Anda, L. [Laboratoire de Physique des Solides–UMR 8502, Université Paris-Sud & CNRS, 91405 Orsay (France)

    2015-10-14

    We theoretically investigate the pitch of lyotropic cholesteric phases composed of slender rods with steric chirality transmitted via a weak helical deformation of the backbone. In this limit, the model is amenable to analytical treatment within Onsager theory and a closed expression for the pitch versus concentration and helical shape can be derived. Within the same framework, we also briefly review the possibility of alternative types of chiral order, such as twist-bend or screw-like nematic phases, finding that cholesteric order dominates for weakly helical distortions. While long-ranged or “soft” chiral forces usually lead to a pitch decreasing linearly with concentration, steric chirality leads to a much steeper decrease of quadratic nature. This reveals a subtle link between the range of chiral intermolecular interaction and the pitch sensitivity with concentration. A much richer dependence on the thermodynamic state is revealed for polar helices where parallel and anti-parallel pair alignments along the local director are no longer equivalent. It is found that weak temperature variations may lead to dramatic changes in the pitch, despite the lyotropic nature of the assembly.

  20. Direct evidence for sequence-dependent attraction between double-stranded DNA controlled by methylation

    Science.gov (United States)

    Yoo, Jejoong; Kim, Hajin; Aksimentiev, Aleksei; Ha, Taekjip

    2016-03-01

    Although proteins mediate highly ordered DNA organization in vivo, theoretical studies suggest that homologous DNA duplexes can preferentially associate with one another even in the absence of proteins. Here we combine molecular dynamics simulations with single-molecule fluorescence resonance energy transfer experiments to examine the interactions between duplex DNA in the presence of spermine, a biological polycation. We find that AT-rich DNA duplexes associate more strongly than GC-rich duplexes, regardless of the sequence homology. Methyl groups of thymine acts as a steric block, relocating spermine from major grooves to interhelical regions, thereby increasing DNA-DNA attraction. Indeed, methylation of cytosines makes attraction between GC-rich DNA as strong as that between AT-rich DNA. Recent genome-wide chromosome organization studies showed that remote contact frequencies are higher for AT-rich and methylated DNA, suggesting that direct DNA-DNA interactions that we report here may play a role in the chromosome organization and gene regulation.

  1. Steric effects in the dynamics of electrolytes at large applied voltages: II. Modified Poisson-Nernst-Planck equations

    CERN Document Server

    Kilic, M S; Ajdari, A; Kilic, Mustafa Sabri; Bazant, Martin Z.; Ajdari, Armand

    2006-01-01

    In situations involving large potentials or surface charges, the Poisson Boltzman(PB) equation has shortcomings because it neglects ion-ion interactions and steric effects. This has been widely recognized by the electrochemistry community, leading to the development of various alternative models resulting in different sets "modified PB equations", which have had at least qualitative success in predicting equilibrium ion distributions. On the other hand, the literature is scarce in terms of descriptions of concentration dynamics in these regimes. Here, adapting strategies developed to modify the PB equation, we propose a simple modification of the widely used Poisson-Nernst-Planck (PNP) equations for ionic transport, which at least qualitatively accounts for steric effects. We analyze numerical solutions of these MPNP equations on the model problem of the charging of a simple electrolyte cell, and compare the outcome to that of the standard PNP equations. Finally, we repeat the asymptotic analysis of Bazant, T...

  2. Optimized steric stabilization of aqueous ferrofluids and magnetic nanoparticles.

    Science.gov (United States)

    Jain, Nirmesh; Wang, Yanjun; Jones, Stephen K; Hawkett, Brian S; Warr, Gregory G

    2010-03-16

    The preparation and properties of an aqueous ferrofluid consisting of a concentrated (>65 wt %) dispersion of sterically stabilized superparamagnetic, iron oxide (maghemite) nanoparticles stable for several months at high ionic strength and over a broad pH range is described. The 6-8 nm diameter nanoparticles are individually coated with a short poly(acrylic acid)-b-poly(acrylamide) copolymer, designed to form the thinnest possible steric stabilizing layer while remaining strongly attached to the iron oxide surface over a wide range of nanoparticle concentrations. Thermogravimetric analysis yields an iron oxide content of 76 wt % in the dried particles, consistent with a dry polymer coating of approximately 1 nm in thickness, while the poly(acrylamide) chain length indicated by electrospray mass spectrometry is consistent with the 4-5 nm increase in the hydrodynamic radius observed by light scattering when the poly(acrylamide) stabilizing chains are solvated. Saturation magnetization experiments indicate nonmagnetic surface layers resulting from the strong chemical attachment of the poly(acrylic acid) block to the particle surface, also observed by Fourier transform infrared spectroscopy. PMID:19950943

  3. Attractants in purified diets

    OpenAIRE

    Pascual, Felicitas P.

    1980-01-01

    Juvenile Penaeus monodon were reared on purified diets containing different attractants used to gelatinize the cornstarch: plain water, shrimp, mussel, squid or trash fish extract. The highest survival rate was observed in the group given the shrimp attractant, followed by mussel, fish and squid. However growth appeared best in the diet containing mussel extract. Mussel extract apparently can be used to enhance the attractability of purified diets.

  4. Attractive faces temporally modulate visual attention

    Directory of Open Access Journals (Sweden)

    Koyo eNakamura

    2014-06-01

    Full Text Available Facial attractiveness is an important biological and social signal on social interaction. Recent research has demonstrated that an attractive face captures greater spatial attention than an unattractive face does. Little is known, however, about the temporal characteristics of visual attention for facial attractiveness. In this study, we investigated the temporal modulation of visual attention induced by facial attractiveness by using a rapid serial visual presentation (RSVP. Fourteen male faces and two female faces were successively presented for 160 ms respectively, and participants were asked to identify two female faces embedded among a series of multiple male distractor faces. Identification of a second female target (T2 was impaired when a first target (T1 was attractive compared to neutral or unattractive faces, at 320 ms SOA; identification was improved when T1 was attractive compared to unattractive faces at 640 ms SOA. These findings suggest that the spontaneous appraisal of facial attractiveness modulates temporal attention.

  5. A steric tethering approach enables palladium-catalysed C-H activation of primary amino alcohols

    Science.gov (United States)

    Calleja, Jonas; Pla, Daniel; Gorman, Timothy W.; Domingo, Victoriano; Haffemayer, Benjamin; Gaunt, Matthew J.

    2015-12-01

    Aliphatic primary amines are a class of chemical feedstock essential to the synthesis of higher-order nitrogen-containing molecules, commonly found in biologically active compounds and pharmaceutical agents. New methods for the construction of complex amines remain a continuous challenge to synthetic chemists. Here, we outline a general palladium-catalysed strategy for the functionalization of aliphatic C-H bonds within amino alcohols, an important class of small molecule. Central to this strategy is the temporary conversion of catalytically incompatible primary amino alcohols into hindered secondary amines that are capable of undergoing a sterically promoted palladium-catalysed C-H activation. Furthermore, a hydrogen bond between amine and catalyst intensifies interactions around the palladium and orients the aliphatic amine substituents in an ideal geometry for C-H activation. This catalytic method directly transforms simple, easily accessible amines into highly substituted, functionally concentrated and structurally diverse products, and can streamline the synthesis of biologically important amine-containing molecules.

  6. Intelligence and Physical Attractiveness

    Science.gov (United States)

    Kanazawa, Satoshi

    2011-01-01

    This brief research note aims to estimate the magnitude of the association between general intelligence and physical attractiveness with large nationally representative samples from two nations. In the United Kingdom, attractive children are more intelligent by 12.4 IQ points (r=0.381), whereas in the United States, the correlation between…

  7. Assertiveness and Physical Attractiveness.

    Science.gov (United States)

    Kleim, David M.; And Others

    Earlier research investigating the relationship between physical attractiveness and assertiveness found that physically attractive females were more assertive than other females. To investigate this relationship further and to broaden the scope of the study, 69 students were videotaped in groups of five to ten while responding to open-ended…

  8. Expression of Power and Heterosexual Attraction.

    Science.gov (United States)

    DeBlasio, Cynthia L.; Ellyson, Steve L.

    Facial attractiveness has been the focus of considerable research in social psychology. Nonverbal behaviors emitted by the face may affect the perceived attractiveness of males and females differently. Visual behavior has particularly important functions in regulating social interaction and in establishing and conveying social power. Power and…

  9. Observation of attraction between dark solitons

    DEFF Research Database (Denmark)

    Dreischuh, A.; Neshev, D.N.; Petersen, D.E.;

    2006-01-01

    We demonstrate a dramatic change in the interaction forces between dark solitons in nonlocal nonlinear media. We present what we believe is the first experimental evidence of attraction of dark solitons. Our results indicate that attraction should be observable in other nonlocal systems...

  10. Finite-size scaling functions for directed polymers confined between attracting walls

    Energy Technology Data Exchange (ETDEWEB)

    Owczarek, A L [Department of Mathematics and Statistics, University of Melbourne, Parkville, Victoria 3052 (Australia); Prellberg, T [School of Mathematical Sciences, Queen Mary, University of London, Mile End Road, London E1 4NS (United Kingdom); Rechnitzer, A [Department of Mathematics, University of British Columbia, Vancouver, BC V6T 1Z2 (Canada)

    2008-01-25

    The exact solution of directed self-avoiding walks confined to a slit of finite width and interacting with the walls of the slit via an attractive potential has been recently calculated. The walks can be considered to model the polymer-induced steric stabilization and sensitized flocculation of colloidal dispersions. The large-width asymptotics led to a phase diagram different to that of a polymer attached to, and attracted to, a single wall. The question that arises is: Can one interpolate between the single wall and two wall cases? In this paper, we calculate the exact scaling functions for the partition function by considering the two variable asymptotics of the partition function for simultaneous large length and large width. Consequently, we find the scaling functions for the force induced by the polymer on the walls. We find that these scaling functions are given by elliptic {theta} functions. In some parts of the phase diagram there is more a complex crossover between the single wall and two wall cases and we elucidate how this happens.

  11. Sterically stabilized water based magnetic fluids: Synthesis, structure and properties

    International Nuclear Information System (INIS)

    Magnetic fluids (MFs), prepared by chemical co-precipitation followed by double layer steric and electrostatic (combined) stabilization of magnetite nanoparticles dispersed in water, are presented. Several combinations of surfactants with different chain lengths (lauric acid (LA), myristic acid (MA), oleic acid (OA) and dodecyl-benzene-sulphonic acid (DBS)) were used, such as LA+LA, MA+MA, LA+DBS, MA+DBS, OA+DBS, OA+OA and DBS+DBS. Static light scattering, transmission electron microscopy, small angle neutron scattering, magnetic and magneto-rheological measurements revealed that MFs with MA+MA or LA+LA biocompatible double layer covered magnetite nanoparticles are the most stable colloidal systems among the investigated samples, and thus suitable for biomedical applications

  12. Steric molecular theory for multiple smectic-A phases

    International Nuclear Information System (INIS)

    Molecular-lattice-theory results reveal that the steric (hard-repulsive) packing of rigid cores and partially flexible tails can explain the relative stabilities of the smectic-A1, smectic-A/sub d/, and higher-temperature and lower-temperature nematic (including reentrant-nematic) liquid-crystalline phases, and the isotropic liquid phase. These phases and transitions between them are presented as a function of temperature, pressure, tail-chain length and flexibility, and orientational and positional order of the molecules for different systems. Critical exponents calculated at the smectic-A/sub d/ to nematic transitions are consistent with an identification of the fraction of one-dimensional positional alignment (i.e., the fraction of segregated packing of cores with cores and thus of tails with tails) of the molecules in the smectic-A/sub d/ phase as an order parameter

  13. Impressions of Counselors as a Function of Counselor Physical Attractiveness

    Science.gov (United States)

    Carter, Jean A.

    1978-01-01

    Research assessed the effects of counselor physical attractiveness and inter-actions between attractiveness and counselor subject sex. It is suggested that sex of counselor and client may play a more important role independently and in conjunction with attractiveness than does attractiveness alone in influencing impressions and expectations.…

  14. Attention Alters Perceived Attractiveness.

    Science.gov (United States)

    Störmer, Viola S; Alvarez, George A

    2016-04-01

    Can attention alter the impression of a face? Previous studies showed that attention modulates the appearance of lower-level visual features. For instance, attention can make a simple stimulus appear to have higher contrast than it actually does. We tested whether attention can also alter the perception of a higher-order property-namely, facial attractiveness. We asked participants to judge the relative attractiveness of two faces after summoning their attention to one of the faces using a briefly presented visual cue. Across trials, participants judged the attended face to be more attractive than the same face when it was unattended. This effect was not due to decision or response biases, but rather was due to changes in perceptual processing of the faces. These results show that attention alters perceived facial attractiveness, and broadly demonstrate that attention can influence higher-level perception and may affect people's initial impressions of one another. PMID:26966228

  15. Physical Attractiveness and Courtship

    Science.gov (United States)

    Silverman, Irwin

    1971-01-01

    This study shows a high and disquieting degree of similarity in physical attractiveness between dating partners, and suggests also that more similar partners tend to form stronger romantic attachments. (Author)

  16. Role of steric effects in protein-directed enediyne cycloaromatization of neocarzinostatin.

    Science.gov (United States)

    Chi, Hung-Wen; Chien, Yi-Chih; Liu, Cheng-Yun; Tseng, Chin-Jui; Lee, Yan-Jiun; Chan, Ja-Lin; Chu, Yu-Ru; Chin, Der-Hang

    2011-02-01

    The antibiotic neocarzinostatin comprises a carrier protein with a well-defined cavity for accommodating an active enediyne chromophore. The protein has two disulfides, one (Cys(37)-Cys(47)) lies on the cavity bottom and the other (Cys(88)-Cys(93)) in a constrained short loop. When the chromophore is not bound to the protein, a thiol-induced cycloaromatization of the enediyne into a tetrahydroindacene derivative is responsible for the potent antitumor activity. When it is protein-bound, the protein diverts the cycloaromatization pathway to form a distinct hydroxyisochromene-type product. How the protein directs the enediyne chemistry is an interesting puzzle, and various suggestions have been proposed in the past. We screened more than fifty thiols and manipulated conditions to locate reaction features and search for factors that could influence the protein directing strength. Thiol- and oxygen-concentration-dependence studies suggested that disulfides, which maintain the steric rigidity of the protein, could play a key role in diverting the cycloaromatization pathway. For direct proofs, we made mutations at each of the two disulfides by replacing sulfur atoms with oxygen. Circular dichroism and two-dimensional NMR spectroscopy studies suggested that the mutations changed neither the protein conformation nor the ligand interactions. Analyses of the thiol-induced cycloaromatization revealed that rupture of Cys(37)-Cys(47) made the protein almost completely lose its chemical directing ability, whereas rupture of Cys(88)-Cys(93) had only a minor influence. The results demonstrated that the steric rigidity of the binding cavity, but not necessary the whole protein, played an important role in the protein-directed mechanism. PMID:21268152

  17. Charge-induced patchy attractions between proteins.

    Science.gov (United States)

    Li, Weimin; Persson, Björn A; Morin, Maxim; Behrens, Manja A; Lund, Mikael; Zackrisson Oskolkova, Malin

    2015-01-15

    Static light scattering (SLS) combined with structure-based Monte Carlo (MC) simulations provide new insights into mechanisms behind anisotropic, attractive protein interactions. A nonmonotonic behavior of the osmotic second virial coefficient as a function of ionic strength is here shown to originate from a few charged amino acids forming an electrostatic attractive patch, highly directional and complementary. Together with Coulombic repulsion, this attractive patch results in two counteracting electrostatic contributions to the interaction free energy which, by operating over different length scales, is manifested in a subtle, salt-induced minimum in the second virial coefficient as observed in both experiment and simulations. PMID:25494398

  18. Steric spacing of molecular linkers on passivated Si(111) photoelectrodes.

    Science.gov (United States)

    Li, Feng; Basile, Victoria M; Pekarek, Ryan T; Rose, Michael J

    2014-11-26

    Surfaces with high photoelectrochemical and electronic quality can be prepared by tethering small molecules to single-crystalline Si(111) surfaces using a two-step halogenation/alkylation method (by Lewis and co-workers).1-7 We report here that the surface coverage of custom-synthesized, phenyl-based molecular linkers can be controlled by varying the steric size of R-groups (R=CH3, C6H11, 2-ethylhexyl) at the periphery of the linker. Additionally, the linkers possess a para triflate group (-O2SCF3) that serves as a convenient analytical marker and as a point of covalent attachment for a redox active label. Quantitative X-ray photoelectron spectroscopy (XPS) measurements revealed that the surface coverage systematically varies according to the steric size of the linker: CH3 (6.7±0.8%), CyHex (2.9±1.2%), EtHex (2.1±0.9%). The stability of the photoelectrochemical cyclic voltammetry (PEC-CV) behavior was dependent on an additional methylation step (with CH3MgCl) to passivate residual Si(111)-Cl bonds. Subsequently, the triflate functional group was utilized to perform Pd-catalyzed Heck coupling of vinylferrocene to the surface-attached linkers. Ferrocene surface coverages measured from cyclic voltammetry on the ferrocene-functionalized surfaces Si(111)-8a/CH3-Fc (R=CH3) and Si(111)-8c/CH3-Fc (R=2-EtHex) are consistent with the corresponding Fe 2p XPS coverages and suggest a ∼1:1 conversion of surface triflate groups to vinyl-Fc sites. The surface defect densities of the linker/CH3 modified surfaces are dependent on the coverage and composition of the organic layer. Surface recombination velocity (SRV) measurements indicated that n-Si(111)-8a/CH3 and the ferrocene coupled n-Si(111)-8a/CH3-Fc exhibited relatively high surface carrier lifetimes (4.51 and 3.88 μs, respectively) and correspondingly low S values (3880 and 4510 cm s(-1)). Thus, the multistep, linker/Fc functionalized surfaces exhibit analogously low trap state densities as compared to the fully

  19. Effects of effective attractive multi-body interaction on quantum phase and transport dynamics of a strongly correlated bosonic gas across the superfluid to Mott insulator transition

    International Nuclear Information System (INIS)

    We theoretically investigate quantum phases and transport dynamics of ultracold atoms trapped in an optical lattice in the presence of effective multi-body interaction. When a harmonic external potential is added, several interesting phenomena are revealed, such as the broadening and the emergence of a central insulator plateau and the phase transition between superfluid and Mott insulator phase. We also study the transport of the system which runs across the superfluid—insulator transition after ramping up the lattice, and predict a slower relaxation which is attributed to the influence of the multi-body interaction on the mass transport

  20. Attracting International Hotels

    DEFF Research Database (Denmark)

    Assaf, A. George; Josiassen, Alexander; Agbola, Frank Wogbe

    2015-01-01

    their presence has several positive effects. Using, for the first time, actual on-location data we investigate the factors that matter most for international hotels when selecting host destinations. Specifically, we identify 23 factors that make a destination an attractive (or unattractive) location......With the increased international competition facing hotel chains, it is essential that the next destination they enter is the most attractive option possible. The host destinations too have a keen interest in strategically positioning themselves in order to attract international hotels since...... for international hotels. We then rank these. The results show that welcomeness, infrastructure, and crime rate are the three most important factors that influence the location of international hotels in host destinations....

  1. Modulated nematic structures induced by chirality and steric polarization

    Science.gov (United States)

    Longa, Lech; PajÄ k, Grzegorz

    2016-04-01

    What kind of one-dimensional modulated nematic structures (ODMNS) can form nonchiral and chiral bent-core and dimeric materials? Here, using the Landau-de Gennes theory of nematics, extended to account for molecular steric polarization, we study a possibility of formation of ODMNS, both in nonchiral and intrinsically chiral liquid crystalline materials. Besides nematic and cholesteric phases, we find four bulk ODMNS for nonchiral materials, two of which, to the best of our knowledge, have not been reported so far. These two structures are longitudinal (NLP) and transverse (NTP) periodic waves where the polarization field being periodic in one dimension stays parallel and perpendicular, respectively, to the wave vector. The other two phases are the twist-bend nematic phase (NTB) and the splay-bend nematic phase (NSB), but their fine structure appears more complex than that considered so far. The presence of molecular chirality converts nonchiral NTP and NSB into new NTB phases. Surprisingly, the nonchiral NLP phase can stay stable even in the presence of intrinsic chirality.

  2. Attracting Girls to Physics

    Science.gov (United States)

    Sandow, Barbara; Marks, Ann; Borg, Anne

    2009-04-01

    In most countries the number of girls studying physics, as well female physicists in academic positions, is still low. Active recruitment at all levels is essential to change this situation. In some countries a large proportion of students are female, but career progression is difficult. Highlighting the broad spectrum of career opportunities for those with physics qualifications is a major approach in attracting girls to physics. This paper presents findings, examples of best practices, and recommendations resulting from the workshop, Attracting Girls to Physics, organized as part of the Third IUPAP International Conference on Women in Physics, Seoul, 2008.

  3. Timetable Attractiveness Parameters

    DEFF Research Database (Denmark)

    Schittenhelm, Bernd

    2008-01-01

    Timetable attractiveness is influenced by a set of key parameters that are described in this article. Regarding the superior structure of the timetable, the trend in Europe goes towards periodic regular interval timetables. Regular departures and focus on optimal transfer possibilities make these...... timetables attractive. The travel time in the timetable depends on the characteristics of the infrastructure and rolling stock, the heterogeneity of the planned train traffic and the necessary number of transfers on the passenger’s journey. Planned interdependencies between trains, such as transfers and...

  4. Hydrodynamic attraction of swimming microorganisms by surfaces

    OpenAIRE

    Berke, Allison P.; Turner, Linda; Berg, Howard C.; Lauga, Eric

    2008-01-01

    Cells swimming in confined environments are attracted by surfaces. We measure the steady-state distribution of smooth-swimming bacteria (Escherichia coli) between two glass plates. In agreement with earlier studies, we find a strong increase of the cell concentration at the boundaries. We demonstrate theoretically that hydrodynamic interactions of the swimming cells with solid surfaces lead to their re-orientation in the direction parallel to the surfaces, as well as their attraction by the c...

  5. Attractiveness of Invariant Manifolds

    CERN Document Server

    Pei, Lijun

    2011-01-01

    In this paper an operable, universal and simple theory on the attractiveness of the invariant manifolds is first obtained. It is motivated by the Lyapunov direct method. It means that for any point $\\overrightarrow{x}$ in the invariant manifold $M$, $n(\\overrightarrow{x})$ is the normal passing by $\\overrightarrow{x}$, and $\\forall \\overrightarrow{x^{'}} \\in n(\\overrightarrow{x})$, if the tangent $f(\\overrightarrow{x^{'}})$ of the orbits of the dynamical system intersects at obtuse (sharp) angle with the normal $n(\\overrightarrow{x})$, or the inner product of the normal vector $\\overrightarrow{n}(\\overrightarrow{x})$ and tangent vector $\\overrightarrow{f}(\\overrightarrow{x^{'}})$ is negative (positive), i.e., $\\overrightarrow{f}(\\overrightarrow{x^{'}}). \\overrightarrow{n}(\\overrightarrow{x}) )0$, then the invariant manifold $M$ is attractive (repulsive). Some illustrative examples of the invariant manifolds, such as equilibria, periodic solution, stable and unstable manifolds, other invariant manifold are pre...

  6. Chemistry of sex attraction.

    OpenAIRE

    Roelofs, W L

    1995-01-01

    The chemical communication system used to attract mates involves not only the overt chemical signals but also indirectly a great deal of chemistry in the emitter and receiver. As an example, in emitting female moths, this includes enzymes (and cofactors, mRNA, genes) of the pheromone biosynthetic pathways, hormones (and genes) involved in controlling pheromone production, receptors and second messengers for the hormones, and host plant cues that control release of the hormone. In receiving ma...

  7. Interocular conflict attracts attention.

    Science.gov (United States)

    Paffen, Chris L E; Hessels, Roy S; Van der Stigchel, Stefan

    2012-02-01

    During binocular rivalry, perception alternates.between dissimilar images presented dichoptically. Since.its discovery, researchers have debated whether the phenomenon is subject to attentional control. While it is now clear that attentional control over binocular rivalry is possible, the opposite is less evident: Is interocular conflict (i.e., the situation leading to binocular rivalry) able to attract attention?In order to answer this question, we used a change blindness paradigm in which observers looked for salient changes in two alternating frames depicting natural scenes. Each frame contained two images: one for the left and one for the right eye. Changes occurring in a single image (monocular) were detected faster than those occurring in both images (binocular). In addition,monocular change detection was also faster than detection in fused versions of the changed and unchanged regions. These results show that interocular conflict is capable of attracting attention, since it guides visual attention toward salient changes that otherwise would remain unnoticed for longer. The results of a second experiment indicated that interocular conflict attracts attention during the first phase of presentation, a phase during which the stimulus is abnormally fused [added]. PMID:22167536

  8. Tuning and Quantifying Steric and Electronic Effects of N-Heterocyclic Carbenes

    KAUST Repository

    Falivene, Laura

    2014-07-12

    This chapter states that the main handles for tuning steric and electronic effects are the substituents on N atoms, the nature of the C4-C5 bridge (either saturated or unsaturated), and the substituents on the C4 and C5 atoms. The initial intuition that steric properties of N-heterocyclic carbenes (NHCs) could be modulated and could impact catalytic behavior stimulated the development of steric descriptors to quantify the steric requirement of different NHCs and, possibly, to compare them with tertiary phosphines. NHCs can be classified as typically strong σ-basic/π-acid ligands, although they have been also shown to exhibit reasonable π-basic properties. This electronic modularity allows NHC ligands to adapt flexibly to different chemical environments represented by a transition metal and the other ligands. © 2014 Wiley-VCH Verlag GmbH & Co. KGaA. All rights reserved.

  9. Synthesis of substituted polyaryls via sterically hindered double Suzuki cross-couplings

    Institute of Scientific and Technical Information of China (English)

    Zhan Zhang; Hai Ying Ji; Xian Lei Fu; Yu Yang; Yun Rong Xue; Guo Hua Gao

    2009-01-01

    Substituted polyaryls were synthesized successfully via sterically hindered double Suzuki cross-couplings of arylboronic acids with aryl dibromides in the presence of Pd(PPh3)4 and KOtBu within a very short time.

  10. Synthesis and dynamic behaviour of new metallo-based sterically overcrowded alkenes

    NARCIS (Netherlands)

    Smid, WI; Schoevaars, AM; Kruizinga, W; Veldman, N; Smeets, WJJ; Spek, AL; Feringa, BL; Smeets, Wilberth J.J.; Spek, Anthony L.; Feringa, Bernard

    1996-01-01

    The synthesis and crystal and molecular structures of novel metallo-based sterically overcrowded alkenes are reported and dynamic H-1 NMR studies reveals that the isomerization barriers are dramatically increased on metal coordination.

  11. The Role of Attractiveness and Aggression in High School Popularity

    Science.gov (United States)

    Borch, Casey; Hyde, Allen; Cillessen, Antonius H. N.

    2011-01-01

    This study examines the effects of physical attractiveness and aggression on popularity among high school students. Previous work has found positive relationships between aggression and popularity and physical attractiveness and popularity. The current study goes beyond this work by examining the interactive effects of physical attractiveness and…

  12. Sulfur-Specific Microbial Desulfurization of Sterically Hindered Analogs of Dibenzothiophene

    OpenAIRE

    Lee, M. K.; Senius, J. D.; Grossman, M. J.

    1995-01-01

    Dibenzothiophenes (DBTs) bearing alkyl substitutions adjacent to the sulfur atom, such as 4,6-diethyldibenzothiophene (4,6-DEDBT), are referred to as sterically hindered with regard to access to the sulfur moiety. By using enrichment cultures with 4,6-DEDBT as the sole sulfur source, bacterial isolates which selectively remove sulfur from sterically hindered DBTs were obtained. The isolates were tentatively identified as Arthrobacter species. 4,6-DEDBT sulfone was shown to be an intermediate ...

  13. A protocol for amide bond formation with electron deficient amines and sterically hindered substrates

    DEFF Research Database (Denmark)

    Due-Hansen, Maria E; Pandey, Sunil K; Christiansen, Elisabeth; Andersen, Rikke; Hansen, Steffen V F; Ulven, Trond

    2016-01-01

    A protocol for amide coupling by in situ formation of acyl fluorides and reaction with amines at elevated temperature has been developed and found to be efficient for coupling of sterically hindered substrates and electron deficient amines where standard methods failed.......A protocol for amide coupling by in situ formation of acyl fluorides and reaction with amines at elevated temperature has been developed and found to be efficient for coupling of sterically hindered substrates and electron deficient amines where standard methods failed....

  14. Steric and electronic effects of 1,3-disubstituted cyclopentadienyl ligands on metallocene derivatives of Cerium, Titanium, Manganese, and Iron

    Energy Technology Data Exchange (ETDEWEB)

    Sofield, C.D.

    2000-05-19

    Sterically demanding 1,3-disubstituted cyclopentadienyl ligands were used to modify the physical properties of the corresponding metallocenes. Sterically demanding ligands provided kinetic stabilization for trivalent cerium compounds. Tris(di-t-butylcyclopentadienyl)cerium was prepared and anion competition between halides and cyclopentadienyl groups which had complicated synthesis of the tris(cyclopentadienyl)compound was qualitatively examined. Bis(di-t-butylcyclopentadienyl)cerium methyl was prepared and its rate of decomposition, by ligand redistribution, to tris(di-t-butylcyclopentadienyl)cerium was shown to be slower than the corresponding rate for less sterically demanding ligands. Asymmetrically substituted ligands provided a symmetry label for examination of chemical exchange processes. Tris[trimethylsilyl(t-butyl)cyclopentadienyl]cerium was prepared and the rate of interconversion between the C1 and C3 isomers was examined. The enthalpy difference between the two distereomers is 7.0 kJ/mol. The sterically demanding cyclopentadienyl ligands ansa-di-t-butylcyclopentadiene (Me2Si[(Me3C)2C5H3]2), ansa-bis(trimethylsilyl)cyclopentadiene (Me2Si[(Me3Si)2C5H3]2) and tetra-t-butylfulvalene and metallocene derivatives of the ligands were prepared and their structures were examined by single crystal X-ray crystallography. The effect that substituents on the cyclopentadienyl ring have on the pi-electron system of the ligand was examined through interaction between ligand and metal orbitals. A series of 1,3-disubstituted manganocenes was prepared and their electronic states were determined by solid-state magnetic susceptibility, electron paramagnetic resonance, X-ray crystallography, and variable temperature UV-vis spectroscopy. Spin-equilibria in [(Me3C)2C5H3]2Mn and [(Me3C)(Me3Si)C5H3]2Mn were examined and indicate an enthalpy difference of 15 kJ/mol between the high-spin and low-spin forms. Cyclopentadienyl groups resistant to intramolecular oxidative addition

  15. Influence of the steric effect of flexible isomeric phenylenediacetic acids on the resultant lead(II) coordination polymers

    International Nuclear Information System (INIS)

    To study the steric effect of the flexible dicarboxylate ligands on the resultant formations of coordination polymers (CPs), four new PbII CPs [Pb(1,2-pda)(H2O)]n (1), [Pb(1,3-pda)]n·nH2O (2), [Pb2(1,4-pda)2(H2O)]n·2nH2O (3a and 3b) have been produced by the isomeric phenylenediacetic acids (H2pda). The X-ray crystallography study reveals that CP 1 is a two-dimensional (2D) 4-connected sql (44.62) network via the weak Pb···O interactions built on 1D chain-like structure. CP 2 crystallizes in orthorhombic system with chiral space group P212121, showing a 4-connected sra (42.63.8) framework where a left-handed helical motif is formed by PbII ions and trans-1,3-pda ligands. More interestingly, CPs 3a and 3b are two true 3D polymorphs and have the different morphology. Topologically, the framework of 3a exhibits a 4-connected lon 66 motif, while that of 3b is a (4,6)-connected fsh (43.63)2(46.66.83) net. It is found that the three isomeric pda anions display the various coordination fashions in four CPs. The different structural arrangements show that the steric effect of the isomeric H2pda tectons has a positive role in directing the final products of PbII CPs. Also, the fluorescent properties of the CPs were studied in the solid state at room temperature. - Graphical abstract: Four new PbII-based CPs have been produced by the isomeric phenylenediacetic acids (H2pda). The different structural arrangements show that the steric effect of the isomeric H2pda tectons has a positive role in directing the final products of PbII CPs. Also, the fluorescent properties of the CPs were studied in the solid state at room temperature. - Highlights: • Four PbII-based coordination polymers were produced by phenylenediacetic acids. • The crystal and topological structures of the CPs have been investigated carefully. • Different structures show the steric effect of H2pda has a role in directing CPs. • The fluorescence of the CPs were studied in the solid state at room

  16. Effect of fullerene on the dispersibility of nanostructured lipid particles and encapsulation in sterically stabilized emulsions.

    Science.gov (United States)

    Kulkarni, Chandrashekhar V; Moinuddin, Zeinab; Agarwal, Yash

    2016-10-15

    We report on the effect of fullerenes (C60) on the stability of nanostructured lipid emulsions. These (oil-in-water) emulsions are essentially aqueous dispersions of lipid particles exhibiting self-assembled nanostructures at their cores. The majority of previous studies on fullerenes were focused on planar and spherical lipid bilayer systems including pure lipids and liposomes. In this work, fullerenes were interacted with a lipid that forms nanostructured dispersions of non-lamellar self-assemblies. A range of parameters including the composition of emulsions and sonication parameters were examined to determine the influence of fullerenes on in-situ and pre-stabilized lipid emulsions. We found that fullerenes mutually stabilize very low concentrations of lipid molecules, while other concentration emulsions struggle to stay stable or even to form at first instance; we provide hypotheses to support these observations. Interestingly though, we were able to encapsulate varying amounts of fullerenes in sterically stabilized emulsions. This step has a significant positive impact, as we could effectively control an inherent aggregation tendency of fullerenes in aqueous environments. These novel hybrid nanomaterials may open a range of avenues for biotechnological and biomedical applications exploiting properties of both lipid and fullerene nanostructures. PMID:27416287

  17. Attraction of nonlocal dark optical solitons

    DEFF Research Database (Denmark)

    Nikolov, Nikola Ivanov; Neshev, Dragomir; Krolikowski, Wieslaw;

    2004-01-01

    We study the formation and interaction of spatial dark optical solitons in materials with a nonlocal nonlinear response. We show that unlike in local materials, where dark solitons typically repel, the nonlocal nonlinearity leads to a long-range attraction and formation of stable bound states...... of dark solitons. (C) 2004 Optical Society of America...

  18. Physical attractiveness and personality development.

    Science.gov (United States)

    Shea, J; Crossman, S M; Adams, G R

    1978-05-01

    A test of the relationship between physical attractiveness and ego development was completed through an interview study of 294 men and women college students. Ss responded to personality measures assessing identity formation, locus of control, and ego functioning and were rated on facial attractiveness and body form scales. Contrary to the physical attractiveness stereotype, attractive and unattractive Ss did not differ in their personality styles. PMID:650605

  19. Attracting Girls Into Physics

    Science.gov (United States)

    Hosny, Hala M.; Kahil, Heba M.

    2005-10-01

    From our national statistics, it is evident that in the population of physicists there are considerably fewer women than men. Our role is to attract girls to physics and thus decrease this gap. The institutional structure in Egypt provides an equal opportunity for girls to study sciences, including physics. It is reckoned that girls refrain from studying physics due to a group of social and economic factors. We will discuss teaching physics at schools and present some ideas to develop it. The media should play a role in placing female physicists in the spotlight. Unfortunately, careers that require intellectual skills are considered men's careers. This necessitates that society changes the way it sees women and trusts more in their skills and talents. We therefore call for the cooperation of governmental and nongovernmental bodies, together with universities and the production sectors involved. This will ultimately lead to enhancing the entrepreneurial projects related to physics and technology on the one hand, and will encourage girls to find challenging opportunities on the other.

  20. Attracting foreign companies

    International Nuclear Information System (INIS)

    The question of attracting foreign companies to undertake uranium exploration and development is typically a national problem and has to take into account, among other things, political policy, national needs, investment capability and choice, technological level of the country reached and/or planned. These considerations are not specific to uranium exploration; the same questions can be put for growing corn (or rice), producing television sets, or manufacturing space rockets. The answers are necessarily different for each country. However, mineral exploration (including uranium) presents important differences that are related to the special investment risks associated with these activities. The investor in mining development can never be sure of earning his money back. This will not be the case in other industries as long as the business is operated in an adequate way. Under these conditions it is very difficult to provide precise guide lines. The host country must pay close attention to the risk involved when making incentive regulations. The best way is for the government to understand very well the foreign investor's motivations and to accommodate, as well as possible within national policies, respect for the interests of both parties

  1. Facial Features: What Women Perceive as Attractive and What Men Consider Attractive.

    Science.gov (United States)

    Muñoz-Reyes, José Antonio; Iglesias-Julios, Marta; Pita, Miguel; Turiegano, Enrique

    2015-01-01

    Attractiveness plays an important role in social exchange and in the ability to attract potential mates, especially for women. Several facial traits have been described as reliable indicators of attractiveness in women, but very few studies consider the influence of several measurements simultaneously. In addition, most studies consider just one of two assessments to directly measure attractiveness: either self-evaluation or men's ratings. We explored the relationship between these two estimators of attractiveness and a set of facial traits in a sample of 266 young Spanish women. These traits are: facial fluctuating asymmetry, facial averageness, facial sexual dimorphism, and facial maturity. We made use of the advantage of having recently developed methodologies that enabled us to measure these variables in real faces. We also controlled for three other widely used variables: age, body mass index and waist-to-hip ratio. The inclusion of many different variables allowed us to detect any possible interaction between the features described that could affect attractiveness perception. Our results show that facial fluctuating asymmetry is related both to self-perceived and male-rated attractiveness. Other facial traits are related only to one direct attractiveness measurement: facial averageness and facial maturity only affect men's ratings. Unmodified faces are closer to natural stimuli than are manipulated photographs, and therefore our results support the importance of employing unmodified faces to analyse the factors affecting attractiveness. We also discuss the relatively low equivalence between self-perceived and male-rated attractiveness and how various anthropometric traits are relevant to them in different ways. Finally, we highlight the need to perform integrated-variable studies to fully understand female attractiveness. PMID:26161954

  2. Facial Features: What Women Perceive as Attractive and What Men Consider Attractive.

    Directory of Open Access Journals (Sweden)

    José Antonio Muñoz-Reyes

    Full Text Available Attractiveness plays an important role in social exchange and in the ability to attract potential mates, especially for women. Several facial traits have been described as reliable indicators of attractiveness in women, but very few studies consider the influence of several measurements simultaneously. In addition, most studies consider just one of two assessments to directly measure attractiveness: either self-evaluation or men's ratings. We explored the relationship between these two estimators of attractiveness and a set of facial traits in a sample of 266 young Spanish women. These traits are: facial fluctuating asymmetry, facial averageness, facial sexual dimorphism, and facial maturity. We made use of the advantage of having recently developed methodologies that enabled us to measure these variables in real faces. We also controlled for three other widely used variables: age, body mass index and waist-to-hip ratio. The inclusion of many different variables allowed us to detect any possible interaction between the features described that could affect attractiveness perception. Our results show that facial fluctuating asymmetry is related both to self-perceived and male-rated attractiveness. Other facial traits are related only to one direct attractiveness measurement: facial averageness and facial maturity only affect men's ratings. Unmodified faces are closer to natural stimuli than are manipulated photographs, and therefore our results support the importance of employing unmodified faces to analyse the factors affecting attractiveness. We also discuss the relatively low equivalence between self-perceived and male-rated attractiveness and how various anthropometric traits are relevant to them in different ways. Finally, we highlight the need to perform integrated-variable studies to fully understand female attractiveness.

  3. Hydrodynamic attraction and repulsion between asymmetric rotors

    International Nuclear Information System (INIS)

    At low Reynolds numbers, the hydrodynamic interaction between dumbbells driven by an external rotating field can be attractive or repulsive. Dumbbells of dissimilar asymmetric shape or different coupling to the external field undergo conformational rearrangements that break the time-reversal symmetry. The parameter ranges leading to attraction or repulsion are explored numerically. The results of our simulations suggest that rotating fields may be a useful avenue for the assembly, disassembly and sorting of particles of different shapes, as well as for the study of collective micro-swimmers.

  4. STUDIES ON THE EXCIMER FLUORESCENCE AND THE STERIC TACTICITY OF POLYPHENYLSILSESQUIOXANES

    Institute of Scientific and Technical Information of China (English)

    HUANG Chaoran; XU Guangzhi; ZHANG Xinsheng; SHI Lianghe

    1987-01-01

    The steric tacticity of polyphenylsilsesquioxanes (PPS) was studied by excimer fluorescence spectroscopy. It was found that the fluorescence of PPS come mainly from its intramolecular excimers. The experimental results indicated that the steric-structure of PPS is most probably cis-isotactic rather than the cis-syndiotactic as suggested in the literature. With the increase in defect content monomer fluorescence intensity increases because of the enhanced mobility of phenyl groups. Molecular weights and molecular weight distributions do not affect the fluorescence spectra of PPS.

  5. Sterically Stabilized Poly(3,4-ethylenedioxythiophene) Colloidal Dispersions Doped with Different Sulfonic Acids

    Institute of Scientific and Technical Information of China (English)

    Tie Jun WANG; Ping CHEN; Xiu Jie HU; Shu Yun ZHOU

    2006-01-01

    The preparation of sterically stabilized poly(3, 4-ethylenedioxythiophene)(PEDOT)colloidal dispersions doped with different sulfonic acids is described. Three different sulfonic acids, i.e., p-toluenesulfonic acid, β-naphthalenesuffonic acid and D-camphor-10-sulfonic acid are used, facilitating the preparation of sterically stable PEDOT colloidal particles. The influences of the dopants and concentration of polymeric stabilizer on the yields, morphologies and electrical properties of the resultant colloidal particles were investigated. The colloidal particles with the size ranging from 172 to 334 nm have been obtained in good yields. The compressed pellet conductivity was as high as 4.5 Scm-1.

  6. Shukla-Eliasson Attractive Force: Revisited

    CERN Document Server

    Akbar-Moghanjoughi, M

    2012-01-01

    By investigation of the dielectric response of a Fermi-Dirac plasma in the linear limit and evaluation of the electrostatic potential around the positive stationary test charge, we find that the Shukla-Eliasson attractive force is present for the plasma density range expected in the interiors of large planets for a wide range of plasma atomic-number. This research which is based on the generalized electron Fermi-momentum further confirms the existence of the newly discovered Lennard-Jones-like attractive potential and its inevitable role in plasma crystallization in the cores of planets. Moreover, it is observed that the characteristics of the attractive potential is strongly sensitive to the variation of the plasma density and composition. Current research can also have applications in the study of strong laser-matter interactions and innertially confined plasmas.

  7. Measuring tax attractiveness across countries

    OpenAIRE

    Keller, Sara; Schanz, Deborah

    2013-01-01

    This paper develops a new tax measure - the Tax Attractiveness Index - reflecting the attractiveness of a country's tax environment and the tax planning opportunities that are offered. Specifically, the Tax Attractiveness Index covers 16 different components of real-world tax systems, such as the statutory tax rate, the taxation of dividends and capital gains, withholding taxes, the existence of a group taxation regime, loss offset provision, the double tax treaty network, thin capitalization...

  8. Physical Attractiveness Stereotypes about Marriage: Attractiveness Matching Is Good.

    Science.gov (United States)

    Sussman, Steve; And Others

    Previous research on physical attractiveness stereotypes about marriage have used stimulus individuals in isolation. To examine these attractiveness stereotypes using couples as targets, 72 college students (36 females, 36 males) rated eight photographs of four male-female couple types. Members of each couple were either matched (attractive…

  9. Steric control of regiochemistry in the reactions of methyl substituted pentadienyl cations with isobutene

    OpenAIRE

    Mayr, Herbert; Heilmann, Werner

    1986-01-01

    The dienylic chlorides 1–5 react with isobutene in the presence of zinc chloride/ether in dichloromethane to give the acyclic adducts 6–10 in 64–91% yield. The orientation effects are in contrast to the predictions of perturbational molecular orbital theory and can be explained on the basis of steric effects.

  10. The applicapility of the steric height criteria of the Antarctic Circumpolar Current jets

    Science.gov (United States)

    Tarakanov, Roman

    2016-04-01

    According to the steric height criteria of the jets of the Antarctic Circumpolar Current (ACC) the cores of these jets are kept in time and in a whole circumpolar circle at the same isolines of the steric height. The applicability of these criteria was analyzed on the basis of two databases. The first one is the data of several hydrophysical sections carried out south of Africa which were executed in 2004-2010 along the same track. The second one is the series of daily digital maps of the sea level anomaly (SLA) published by the French CLS agency (www.aviso.oceanobs.com). The analysis was executed by comparing two types of curves along the track. The first one is the differences in the steric heights at the same points between two sections. The second one is the differences in SLA at the same points. The analysis revealed an example of a lack of geometric similarity of these curves for the sections in December 2009 and October 2010 in the southern half of the ACC. This lack is up to 10 cm in the SLA values. This fact points to inapplicability of the steric height criteria of the ACC jets in general. In the other words there is no permanent no-motion surface (depth) in the ACC even in time.

  11. .I.Ortho./I. effect and steric inhibition of resonance: basicities of methyl-substituted acetophenones

    Czech Academy of Sciences Publication Activity Database

    Otyepková, E.; Nevěčná, T.; Kulhánek, J.; Exner, Otto

    2003-01-01

    Roč. 16, - (2003), s. 721-725. ISSN 0894-3230 R&D Projects: GA MŠk LN00A032 Institutional research plan: CEZ:AV0Z4055905 Keywords : acetophenones * acid ity function * steric effects Subject RIV: CC - Organic Chemistry Impact factor: 1.182, year: 2003

  12. Steric and mass-induced sea level variations in the Mediterranean Sea revisited

    Science.gov (United States)

    GarcíA-GarcíA, D.; Chao, B. F.; Boy, J.-P.

    2010-12-01

    The total sea level variation (SLV) is the combination of steric and mass-induced SLV, whose exact shares are key to understanding the oceanic response to climate system changes. Total SLV can be observed by radar altimetry satellites such as TOPEX/POSEIDON and Jason 1/2. The steric SLV can be computed through temperature and salinity profiles from in situ measurements or from ocean general circulation models (OGCM), which can assimilate the said observations. The mass-induced SLV can be estimated from its time-variable gravity (TVG) signals. We revisit this problem in the Mediterranean Sea estimating the observed, steric, and mass-induced SLV, for the latter we analyze the latest TVG data set from the GRACE (Gravity Recovery and Climate Experiment) satellite mission launched in 2002, which is 3.5 times longer than in previous studies, with the application of a two-stage anisotropic filter to reduce the noise in high-degree and -order spherical harmonic coefficients. We confirm that the intra-annual total SLV are only produced by water mass changes, a fact explained in the literature as a result of the wind field around the Gibraltar Strait. The steric SLV estimated from the residual of "altimetry minus GRACE" agrees in phase with that estimated from OGCMs and in situ measurements, although showing a higher amplitude. The net water fluxes through both the straits of Gibraltar and Sicily have also been estimated accordingly.

  13. Micro-flow synthesis and structural analysis of sterically crowded diimine ligands with five aryl rings

    Directory of Open Access Journals (Sweden)

    Shinichiro Fuse

    2013-11-01

    Full Text Available Sterically crowded diimine ligands with five aryl rings were prepared in one step in good yields using a micro-flow technique. X-ray crystallographic analysis revealed the detailed structure of the bulky ligands. The nickel complexes prepared from the ligands exerted high polymerization activity in the ethylene homopolymerization and copolymerization of ethylene with polar monomers.

  14. Comparing the steric height in the Nordic Seas with satellite altimeter sea surface height

    Institute of Scientific and Technical Information of China (English)

    SHAO Qiuli; ZHAO Jinping

    2015-01-01

    In this study the steric height anomaly which is calculated from the hydrological data (EN3) is compared with the sea level anomaly derived from satellite altimetry in the Nordic Seas. The overall pattern of steric height is that it is higher in the margin area and lower in the middle area. The extreme values of steric height linear change from 1993 to 2010 occur in the Lofoten Basin and off the Norwegian coast, respectively. Such a distribution may be partly attributed to the freshening trend of the Nordic Seas. The correlation between SLA (sea level anomaly) and SHA (steric height anomaly) is not uniform over the Nordic Seas. The time series of SLA and SHA agree well in the Lofoten Basin and northern Norwegian Basin, and worse in the northern Norwegian Sea, implying that the baroclinic effect plays a dominant role in most areas in the Norwegian Sea and the barotropic effect plays a dominant role in the northern Norwegian Sea. The weaker correlations between SLA and SHA in the Greenland and Iceland Seas lead a conclusion that the barotropic contribution is significant in these areas. The area-mean SHA over the entire Nordic Seas has similar amplitudes compared with the SLA during 1996–2002, but SHA has become lower than SLA, being less than half of SLA since 2006.

  15. Carbamate Stabilities of Sterically Hindered Amines from Quantum Chemical Methods: Relevance ofr CO2 Capture

    NARCIS (Netherlands)

    Gangarapu, S.; Marcelis, A.T.M.; Zuilhof, H.

    2013-01-01

    The influence of electronic and steric effects on the stabilities of carbamates formed from the reaction of CO2 with a wide range of alkanolamines was investigated by quantum chemical methods. For the calculations, B3LYP, M11-L, MP2, and spin-component-scaled MP2 (SCS-MP2) methods were used, coupled

  16. The controlled intravenous delivery of drugs using PEG-coated sterically stabilized nanospheres☆

    OpenAIRE

    Gref, R.; Domb, A.; Quellec, P.; Blunk, T.; Müller, R. H.; Verbavatz, J M; Langer, R

    1995-01-01

    Injectable blood persistent particulate carriers have important therapeutic application in site-specific drug delivery or medical imaging. However, injected particles are generally eliminated by the reticuloendothelial system within minutes after administration and accumulate in the liver and spleen. To obtain a coating that might prevent opsonization and subsequent recognition by the macrophages, sterically stabilized nanospheres were developed using amphiphilic diblock or multiblock copolym...

  17. Steric stabilization of modified nanoclays triggered by temperature.

    Science.gov (United States)

    Cavallaro, Giuseppe; Lazzara, Giuseppe; Milioto, Stefana; Parisi, Filippo

    2016-01-01

    Halloysite clay nanotubes were modified through the adsorption of poly(N-isopropylacrylamide)-amine terminated (PNIPA-NH2) onto the external surface by exploiting electrostatic interactions at pH=6. In spite the amount of attached polymer is rather low (1 wt%), the properties of the nanotubes are deeply modified. The apparent specific volume and isentropic compressibilities of the hybrid nanomaterial dispersed in water evidenced the transferring of the termosensitive property from the polymer to halloysite. The hydrodynamic radius as well as the ζ-potential of the nanohybrid are consistent with the attachment of a positively charged polymer onto the negative surface of the nanotube. The colloidal stability was strongly enhanced in the temperature domain below the lower critical solution temperature. This methodology endowed to obtain hollow nanotubes with a stimuli-responsive corona. PMID:26409004

  18. Physical Attractiveness and Courtship Progress.

    Science.gov (United States)

    White, Gregory L.

    1980-01-01

    Among college students who were casual or serious daters, greater relative attractiveness was positively correlated with greater relative availability of opposite-sexed friends and negatively correlated with worrying about partner's potential involvement with others. A 9-month follow-up revealed that similarity of attractiveness was predictive of…

  19. Physical Attractiveness and Interpersonal Influence

    Science.gov (United States)

    Dion, Karen K.; Stein, Steven

    1978-01-01

    Examines the hypothesis that attractive individuals should be more successful with opposite-sex peers but less successful with same-sex peers than unattractive individuals. Also investigates the influence strategies employed by persons differing in attractiveness since nothing is currently known about the actual behavior exhibited by attractive…

  20. Physical attractiveness stereotype and memory.

    Science.gov (United States)

    Rohner, Jean-Christophe; Rasmussen, Anders

    2011-08-01

    Three experiments examined explicit and implicit memory for information that is congruent with the physical attractiveness stereotype (i.e. attractive-positive and unattractive-negative) and information that is incongruent with the physical attractiveness stereotype (i.e. attractive-negative and unattractive-positive). Measures of explicit recognition sensitivity and implicit discriminability revealed a memorial advantage for congruent compared to incongruent information, as evident from hit and false alarm rates and reaction times, respectively. Measures of explicit memory showed a recognition bias toward congruent compared to incongruent information, where participants tended to call congruent information old, independently of whether the information had been shown previously or not. This recognition bias was unrelated to reports of subjective confidence in retrieval. The present findings shed light on the cognitive mechanisms that might mediate discriminatory behavior towards physically attractive and physically unattractive individuals. PMID:21255024

  1. Facial attractiveness and stereotypes of hotel guests

    OpenAIRE

    Čivre, Žana; Knežević, Mladen; Zabukovec Baruca, Petra; Fabjan, Daša

    2013-01-01

    The purpose of this research was to determine social interaction between hospitality employees and their guests, and consequently assess how front-line employees categorize and stereotype hotel guests based on their facial attractiveness with reference to three main characteristics. Social stereotypes represent a means of information transmission in the communication process and can enable a more rapid transfer of information during the service delivery in the hospitality industry. The experi...

  2. Influence of the steric effect of flexible isomeric phenylenediacetic acids on the resultant lead(II) coordination polymers

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Yunlong; Zhao, Yanqing; Yang, Guo-Ping, E-mail: ygp@nwu.edu.cn; Guo, Yanjun; Wang, Yao-Yu, E-mail: wyaoyu@nwu.edu.cn; Shi, Qi-Zhen

    2015-03-15

    To study the steric effect of the flexible dicarboxylate ligands on the resultant formations of coordination polymers (CPs), four new Pb{sup II} CPs [Pb(1,2-pda)(H{sub 2}O)]{sub n} (1), [Pb(1,3-pda)]{sub n}·nH{sub 2}O (2), [Pb{sub 2}(1,4-pda){sub 2}(H{sub 2}O)]{sub n}·2nH{sub 2}O (3a and 3b) have been produced by the isomeric phenylenediacetic acids (H{sub 2}pda). The X-ray crystallography study reveals that CP 1 is a two-dimensional (2D) 4-connected sql (4{sup 4}.6{sup 2}) network via the weak Pb···O interactions built on 1D chain-like structure. CP 2 crystallizes in orthorhombic system with chiral space group P2{sub 1}2{sub 1}2{sub 1}, showing a 4-connected sra (4{sup 2}.6{sup 3}.8) framework where a left-handed helical motif is formed by Pb{sup II} ions and trans-1,3-pda ligands. More interestingly, CPs 3a and 3b are two true 3D polymorphs and have the different morphology. Topologically, the framework of 3a exhibits a 4-connected lon 6{sup 6} motif, while that of 3b is a (4,6)-connected fsh (4{sup 3}.6{sup 3}){sub 2}(4{sup 6}.6{sup 6}.8{sup 3}) net. It is found that the three isomeric pda anions display the various coordination fashions in four CPs. The different structural arrangements show that the steric effect of the isomeric H{sub 2}pda tectons has a positive role in directing the final products of Pb{sup II} CPs. Also, the fluorescent properties of the CPs were studied in the solid state at room temperature. - Graphical abstract: Four new Pb{sup II}-based CPs have been produced by the isomeric phenylenediacetic acids (H{sub 2}pda). The different structural arrangements show that the steric effect of the isomeric H{sub 2}pda tectons has a positive role in directing the final products of Pb{sup II} CPs. Also, the fluorescent properties of the CPs were studied in the solid state at room temperature. - Highlights: • Four Pb{sup II}-based coordination polymers were produced by phenylenediacetic acids. • The crystal and topological structures of the

  3. Inter-DNA Attraction Mediated by Divalent Counterions

    International Nuclear Information System (INIS)

    Can nonspecifically bound divalent counterions induce attraction between DNA strands? Here, we present experimental evidence demonstrating attraction between short DNA strands mediated by Mg2+ ions. Solution small angle x-ray scattering data collected as a function of DNA concentration enable model independent extraction of the second virial coefficient. As the [Mg2+] increases, this coefficient turns from positive to negative reflecting the transition from repulsive to attractive inter-DNA interaction. This surprising observation is corroborated by independent light scattering experiments. The dependence of the observed attraction on experimental parameters including DNA length provides valuable clues to its origin

  4. Physical Attractiveness Research. Toward a Developmental Social Psychology of Beauty

    Science.gov (United States)

    Adams, G. R.

    1977-01-01

    This paper reviews research on physical attractiveness from a dialectical-interactional perspective and attempts to examine the relationship between outer appearance and inner psychological characteristics from a developmental perspective. (BD)

  5. The shape and dynamics of local attraction

    Science.gov (United States)

    Strömbom, D.; Siljestam, M.; Park, J.; Sumpter, D. J. T.

    2015-11-01

    Moving animal groups, such as flocks of birds or schools of fish, exhibit a varity of self-organized complex dynamical behaviors and shapes. This kind of flocking behavior has been studied using self-propelled particle models, in which the "particles" interact with their nearest neighbors through repulsion, attraction and alignment responses. In particular, it has been shown that models based on attraction alone can generate a range of dynamic groups in 2D, with periodic boundary conditions, and in the absence of repulsion. Here we investigate the effects of changing these conditions on the type of groups observed in the model. We show that replacing the periodic boundary conditions with a weak global attaction term in 2D, and extending the model to 3D does not significantly change the type of groups observed. We also provide a description of how attraction strength and blind angle determine the groups generated in the 3D version of the model. Finally, we show that adding repulsion do change the type of groups oberved, making them appear and behave more like real moving animal groups. Our results suggest that many biological instances of collective motion may be explained without assuming that animals explicitly align with each other. Instead, complex collective motion is explained by the interplay of attraction and repulsion forces. Supplementary material in the form of four mp4 files available from the Journal web page at http://dx.doi.org/10.1140/epjst/e2015-50093-5

  6. The interactions between the sterically demanding trimesitylphosphine oxide and trimesityphosphine with scandium and selected lanthanide ions

    Science.gov (United States)

    Platt, Andrew W. G.; Singh, Kuldip

    2016-05-01

    The reactions between lanthanide nitrates, Ln(NO3)3 and scandium and lanthanide trifluoromethane sulfonates, Ln(Tf)3 with trimesitylphosphine oxide, Mes3PO show that coordination to the metal ions does not lead to crystalline complexes. Investigation of the reactions by 31-P NMR spectroscopy shows that weak complexes are formed in solution. The crystal structures of Mes3PO·0.5CH3CN (1) and [Mes3PO]3H3O·2CH3CN·Tf (2), formed in the reaction between ScTf3 and Mes3PO, are reported. Trimesitylphosphine, Mes3P, is protonated by scandium and lanthanide trifluoromethane sulfonates and lanthanide nitrates in CD3CN and the structure of [Mes3PH]Cl·HCl·2H2O (3) is reported.

  7. Effects of switching behavior for the attraction on pedestrian dynamics

    CERN Document Server

    Kwak, Jaeyoung; Luttinen, Tapio; Kosonen, Iisakki

    2014-01-01

    Walking is a fundamental activity of our daily life not only for moving to other places but also for interacting with surrounding environment. While walking on the streets, pedestrians can be aware of attractions like shopping windows. They can be influenced by the attractions and some of them might shift their attention towards the attractions, namely switching behavior. As a first step to incorporate the switching behavior, this study investigates collective effects of switching behavior for an attraction by developing a behavioral model. Numerical simulations exhibit different patterns of pedestrian behavior depending on the strength of the social influence and the average length of stay. When the social influence is strong along with a long length of stay, a saturated phase can be defined at which all the pedestrians have visited the attraction. If the social influence is not strong enough, an unsaturated phase appears where one can observe that some pedestrians head for the attraction while others walk i...

  8. Depression, Schizophrenia, and Social Attraction.

    Science.gov (United States)

    Boswell, Philip C.; Murray, Edward J.

    1981-01-01

    Compared the dysphoric mood induction and attraction that subjects reported after a vicarious experience with a depressed patient and a comparable experience with a schizophrenic patient. Results showed similar arousal of dysphoric mood and rejection for both patients. (RC)

  9. Short range attraction between two similarly charged silica surfaces

    OpenAIRE

    Zohar, Ohad; Leizerson, Ilya; Sivan, Uri

    2005-01-01

    Using an Atomic Force Microscope (AFM) we measure the interaction between two identically charged silica surfaces in the presence of saline solution. For pure NaCl the interaction is always repulsive. Upon addition of cobalt hexamine ions, [Co(NH3)6]+3, the repulsion is gradually suppressed and a pronounced attraction develops at distances much shorter than the screening length. Higher concentrations of cobalt hexamine turn the attraction back into repulsion. Measurements of surface charge re...

  10. Global Attraction to Solitary Waves

    OpenAIRE

    Komech, Andrey

    2009-01-01

    The long time asymptotics for nonlinear wave equations have been the subject of intensive research, starting with the pioneering papers by Segal, Strauss, and Morawetz, where the nonlinear scattering and local attraction to zero were considered. Global attraction (for large initial data) to zero may not hold if there are quasistationary solitary wave solutions. We will call such solutions "solitary waves". Other appropriate names are "nonlinear eigenfunctions" and "quantum stationary states"....

  11. Effects of student physical attractiveness

    OpenAIRE

    Krnjajić Stevan B.

    2005-01-01

    Implicit personality theories suggest that people draw conclusions about other persons by using a relatively small number of visible features. The formation of "the first impression" is influenced by the factors, such as sex, age, appearances, race or nationality. Frequently, conclusions based on those factors lead to developing social stereotypes. Attractiveness is a good example of "the first impression" effect, because physical attractiveness entails the creation of impression about anothe...

  12. Using steric hindrance to design new inhibitors of class C beta-lactamases

    Energy Technology Data Exchange (ETDEWEB)

    Trehan, Indi; Morandi, F.; Blaszczak, L.C.; Shoichet, Brian K. (NWU)

    2010-03-08

    {beta}-lactamases confer resistance to {beta}-lactam antibiotics such as penicillins and cephalosporins. However, {beta}-lactams that form an acyl-intermediate with the enzyme but subsequently are hindered from forming a catalytically competent conformation seem to be inhibitors of {beta}-lactamases. This inhibition may be imparted by specific groups on the ubiquitous R1 side chain of {beta}-lactams, such as the 2-amino-4-thiazolyl methoxyimino (ATMO) group common among third-generation cephalosporins. Using steric hindrance of deacylation as a design guide, penicillin and carbacephem substrates were converted into effective {beta}-lactamase inhibitors and antiresistance antibiotics. To investigate the structural bases of inhibition, the crystal structures of the acyl-adducts of the penicillin substrate amoxicillin and the new analogous inhibitor ATMO-penicillin were determined. ATMO-penicillin binds in a catalytically incompetent conformation resembling that adopted by third-generation cephalosporins, demonstrating the transferability of such sterically hindered groups in inhibitor design.

  13. Toward overcoming cisplatin resistance via sterically hindered platinum(II) complexes.

    Science.gov (United States)

    Yu, Haiyan; Gou, Shaohua; Wang, Zhimei; Chen, Feihong; Fang, Lei

    2016-05-23

    A number of platinum(II) complexes with steric hindrance derived from (1R,2R)-N(1)-benzylcyclohexane-1,2-diamine derivatives were designed and prepared. Biological assay indicated that most complexes showed antitumor activity against the tested cancer cell lines, especially those with chloride anions as leaving groups had compatible or superior activity to cisplatin and oxaliplatin. Complex 2a, as the most potent agent, is also sensitive to cisplatin resistant SGC7901/CDDP cancer cell line, which has been subsequently studied by cellular uptake, flow cytometry, gel electrophoresis and western blot assays. The steric hindrance resulting from a pending 2-fluorobenzyl moiety of the ligand might be the key factor for its ability to overcome cisplatin resistant cancer cells. PMID:26974381

  14. SambVca 2. A Web Tool for Analyzing Catalytic Pockets with Topographic Steric Maps

    KAUST Repository

    Falivene, Laura

    2016-06-27

    Developing more efficient catalysts remains one of the primary targets of organometallic chemists. To accelerate reaching this goal, effective molecular descriptors and visualization tools can represent a remarkable aid. Here, we present a Web application for analyzing the catalytic pocket of metal complexes using topographic steric maps as a general and unbiased descriptor that is suitable for every class of catalysts. To show the broad applicability of our approach, we first compared the steric map of a series of transition metal complexes presenting popular mono-, di-, and tetracoordinated ligands and three classic zirconocenes. This comparative analysis highlighted similarities and differences between totally unrelated ligands. Then, we focused on a recently developed Fe(II) catalyst that is active in the asymmetric transfer hydrogenation of ketones and imines. Finally, we expand the scope of these tools to rationalize the inversion of enantioselectivity in enzymatic catalysis, achieved by point mutation of three amino acids of mononuclear p-hydroxymandelate synthase.

  15. Steric control of CO binding in a totally synthetic heme protein model

    OpenAIRE

    Busch, Daryle H.; Zimmer, L. Lawrence; Grzybowski, Joseph J.; Olszanski, Dennis J.; Jackels, Susan C.; Callahan, Robert C.; Christoph, Gary G.

    1981-01-01

    A family of totally synthetic models for the carbon monoxide adducts of heme proteins has been synthesized and applied to the elucidation of the role of steric effects in the relative detoxification of carbon monoxide. The complexes are designed such that a sheltered void of controllable dimensions encompasses the CO binding site. Systematic variations in the available space for the iron-bound CO produce a wide range of equilibrium binding constants (KCO). An x-ray structure determination of ...

  16. Low-ppm-Level colorimetric acid detection using gold nanoparticles with electro-steric stabilization.

    Science.gov (United States)

    Bae, Doo Ri; Lee, You-Jin; Lee, Sung Woo; Han, Young-Kyu; Yoon, Jae-Sik; Lee, Ji-Hyun; Lee, Sang-Gil; Chang, Ki Soo; Yi, Gi-Ra; Lee, Gaehang

    2014-12-01

    Electro-sterically stabilized gold suspensions were employed in a colorimetric system for the detection of strong acid in water. Using oleyamine and oleic acid as steric stabilizer in 1,2-dichlorobenzene, hydrophobic gold nanoparticles were first synthesized by a reduction reaction of gold salts and were then transferred into water with a cationic surfactant. When the hydrochlo- ric acid solution higher than critical concentration was injected, particles were quickly aggregated and precipitated, creating a clear solution from the colored suspension. The particles were stable against chemical etching by corrosive ion such as chloride. Critical concentration was dependent of the size and concentration of the particles. The minimum concentration of dramatic color change was at 5 ppm level of hydrochloric acid, in which the largest colloidal gold nanoparticles (54 nm) were used. Furthermore, because of their steric repulsive soft layer on particles, particles could be reused for further detection experiments after regeneration by the simple pH-neutralization and washing process. PMID:25971086

  17. Vocal attractiveness increases by averaging.

    Science.gov (United States)

    Bruckert, Laetitia; Bestelmeyer, Patricia; Latinus, Marianne; Rouger, Julien; Charest, Ian; Rousselet, Guillaume A; Kawahara, Hideki; Belin, Pascal

    2010-01-26

    Vocal attractiveness has a profound influence on listeners-a bias known as the "what sounds beautiful is good" vocal attractiveness stereotype [1]-with tangible impact on a voice owner's success at mating, job applications, and/or elections. The prevailing view holds that attractive voices are those that signal desirable attributes in a potential mate [2-4]-e.g., lower pitch in male voices. However, this account does not explain our preferences in more general social contexts in which voices of both genders are evaluated. Here we show that averaging voices via auditory morphing [5] results in more attractive voices, irrespective of the speaker's or listener's gender. Moreover, we show that this phenomenon is largely explained by two independent by-products of averaging: a smoother voice texture (reduced aperiodicities) and a greater similarity in pitch and timbre with the average of all voices (reduced "distance to mean"). These results provide the first evidence for a phenomenon of vocal attractiveness increases by averaging, analogous to a well-established effect of facial averaging [6, 7]. They highlight prototype-based coding [8] as a central feature of voice perception, emphasizing the similarity in the mechanisms of face and voice perception. PMID:20129047

  18. Meeting Your Match: How Attractiveness Similarity Affects Approach Behavior in Mixed-Sex Dyads

    NARCIS (Netherlands)

    Straaten, I. van; Engels, R.C.M.E.; Finkenauer, C.; Holland, R.W.

    2009-01-01

    This experimental study investigated approach behavior toward opposite-sex others of similar versus dissimilar physical attractiveness. Furthermore, it tested the moderating effects of sex. Single participants interacted with confederates of high and low attractiveness. Observers rated their behavio

  19. Attracted to power: Challenge / threat and promotion / prevention focus differentially predict the attractiveness of group power

    Directory of Open Access Journals (Sweden)

    Annika eScholl

    2015-04-01

    Full Text Available Depending on their motivation, individuals prefer different group contexts for social interactions. The present research sought to provide more insight into this relationship. More specifically, we tested how challenge / threat and a promotion / prevention focus predict attraction to groups with high or low power. As such, we examined differential outcomes of threat and prevention focus as well as challenge and promotion focus that have often been regarded as closely related. According to regulatory focus, individuals should prefer groups that they expect to feel right for them to join: Low-power groups should be more attractive in a prevention (than a promotion focus, as these groups suggest security-oriented strategies, which fit a prevention focus. High-power groups should be more attractive in a promotion (rather than a prevention focus, as these groups are associated with promotion strategies fitting a promotion focus (Sassenberg, Jonas, Shah, & Brazy, 2007. In contrast, under threat (vs. challenge, groups that allow individuals to restore their (perceived lack of control should be preferred: Low-power groups should be less attractive under threat (than challenge because they provide low resources which threatened individuals already perceive as insufficient and high-power groups might be more attractive under threat (than under challenge, because their high resources allow individuals to restore control. Two experiments (N = 140 supported these predictions. The attractiveness of a group often depends on the motivation to engage in what fits (i.e., prefer a group that feels right in the light of one’s regulatory focus. However, under threat the striving to restore control (i.e., prefer a group allowing them to change the statuts quo under threat vs. challenge overrides the fit effect, which may in turn guide individuals’ behavior in social interactions.

  20. Liquid Crystal Phase Behaviour of Attractive Disc-Like Particles

    Directory of Open Access Journals (Sweden)

    George Jackson

    2013-08-01

    Full Text Available We employ a generalized van der Waals-Onsager perturbation theory to construct a free energy functional capable of describing the thermodynamic properties and orientational order of the isotropic and nematic phases of attractive disc particles. The model mesogen is a hard (purely repulsive cylindrical disc particle decorated with an anisotropic square-well attractive potential placed at the centre of mass. Even for isotropic attractive interactions, the resulting overall inter-particle potential is anisotropic, due to the orientation-dependent excluded volume of the underlying hard core. An algebraic equation of state for attractive disc particles is developed by adopting the Onsager trial function to characterize the orientational order in the nematic phase. The theory is then used to represent the fluid-phase behaviour (vapour-liquid, isotropic-nematic, and nematic-nematic of the oblate attractive particles for varying values of the molecular aspect ratio and parameters of the attractive potential. When compared to the phase diagram of their athermal analogues, it is seen that the addition of an attractive interaction facilitates the formation of orientationally-ordered phases. Most interestingly, for certain aspect ratios, a coexistence between two anisotropic nematic phases is exhibited by the attractive disc-like fluids.

  1. Steric Sea Level Trends in the Northeast Pacific Ocean: Possible Evidence of Global Sea Level Rise.

    Science.gov (United States)

    Thomson, Richard E.; Tabata, Susumu

    1989-06-01

    Thirty-year time series of hydrographic observations from Ocean Station PAPA and Line P' are used to estimate secular trends in monthly mean steric sea level heights relative to depths of 100 and 1000 decibars in the northeast Pacific Ocean. Linear trends at station P' (50°N, 145°W) indicate that steric heights relative to the 1000 db (approx. 1000 m) level are rising at a rate of 1.1 mm yr1, comparable with the Order 1 mm yr1 global trends suggested by analysis of selected long-term coastal tide gauge records. Approximately 67% of the increase in steric levels is due to thermosteric change at depths below 100 m, the smaller 33% contribution from the halosteric component apeasrs to be confined to the upper 100 m. Steric height trends at fine P' locations are also of order 1 mm yr1 but, in contrast to station P' trends, arise mainly through the halosteric component.Confidence levels for the linear trends an calculated in two ways. (i) using the Student-t test assuming that cub monthly observation is a statistically independent sample; and (ii) using the Student-t test in conjunction with the effective number of degrees of freedom derived from integral time scales. For station P', trends based on (i) are reliable to the 99% confidence level while for line P' only stations on the eastern portion of the fine have significant trends relative to the 1000 db level. Confidence levels obtained from (i) fail to take into consideration the long-term fluctuations in steric level records. To obtain more reliable estimates of the confidence intervals, we use integral time scales to determine the effective number of degrees of freedom for each monthly time series. Subsequent recalculation of trend-line confidence intervals indicates that the total steric height trends at Station P' remain significant at the 90% confidence level. The halosteric trend relative to 100 db is significant at 90% while the thermosteric trend relative to 1000 db is marginally significant at 70 to 80

  2. Attractive ellipsoids in robust control

    CERN Document Server

    Poznyak, Alexander; Azhmyakov, Vadim

    2014-01-01

    This monograph introduces a newly developed robust-control design technique for a wide class of continuous-time dynamical systems called the “attractive ellipsoid method.” Along with a coherent introduction to the proposed control design and related topics, the monograph studies nonlinear affine control systems in the presence of uncertainty and presents a constructive and easily implementable control strategy that guarantees certain stability properties. The authors discuss linear-style feedback control synthesis in the context of the above-mentioned systems. The development and physical implementation of high-performance robust-feedback controllers that work in the absence of complete information is addressed, with numerous examples to illustrate how to apply the attractive ellipsoid method to mechanical and electromechanical systems. While theorems are proved systematically, the emphasis is on understanding and applying the theory to real-world situations. Attractive Ellipsoids in Robust Control will a...

  3. Peptide folding in the presence of interacting protein crowders

    Science.gov (United States)

    Bille, Anna; Mohanty, Sandipan; Irbäck, Anders

    2016-05-01

    Using Monte Carlo methods, we explore and compare the effects of two protein crowders, BPTI and GB1, on the folding thermodynamics of two peptides, the compact helical trp-cage and the β-hairpin-forming GB1m3. The thermally highly stable crowder proteins are modeled using a fixed backbone and rotatable side-chains, whereas the peptides are free to fold and unfold. In the simulations, the crowder proteins tend to distort the trp-cage fold, while having a stabilizing effect on GB1m3. The extent of the effects on a given peptide depends on the crowder type. Due to a sticky patch on its surface, BPTI causes larger changes than GB1 in the melting properties of the peptides. The observed effects on the peptides stem largely from attractive and specific interactions with the crowder surfaces, and differ from those seen in reference simulations with purely steric crowder particles.

  4. Quantization function for attractive, singular potential tails

    International Nuclear Information System (INIS)

    The interaction between atoms and molecules with each other are deep potential wells with attractive, singular tails. Bound state energies are determined by a quantization function according to a simple quantization rule. This function is dominantly determined by the singular potential tail for near-threshold states. General expressions for the low- and high-energy contributions of the singular potential tail to the quantization function, as well as the connection to the scattering length are presented in two and three dimensions. Precise analytical expressions for the quantization function are determined for the case of potential tails proportional to -1/r4 and -1/r6 for three dimensions. (orig.)

  5. The Ambiguous Attractiveness of Mobility

    DEFF Research Database (Denmark)

    Presskorn-Thygesen, Thomas

    2015-01-01

    ’ can help us understand the attractiveness of constantly being ‘on the move’. Qualitative data from three exemplars of this elite group of workers is used to illustrate how the ideal of being mobile is perceived as an often problematic imperative, but also as one which is nevertheless rewarding and...

  6. Functional Similarity and Interpersonal Attraction.

    Science.gov (United States)

    Neimeyer, Greg J.; Neimeyer, Robert A.

    1981-01-01

    Students participated in dyadic disclosure exercises over a five-week period. Results indicated members of high functional similarity dyads evidenced greater attraction to one another than did members of low functional similarity dyads. "Friendship" pairs of male undergraduates displayed greater functional similarity than did "nominal" pairs from…

  7. Attractiveness and Influence in Counseling

    Science.gov (United States)

    Schmidt, Lyle D.; Strong, Stanley R.

    1971-01-01

    The results showed that in spite of violently different feelings about (or descriptions of) the roles, the subjects were equally influenced by them. This suggests that social attractiveness may not be important when the client's problems require expert opinion and knowledge. (Author/CG(

  8. Physical attractiveness, employment and earnings

    OpenAIRE

    Pfeifer, Christian

    2011-01-01

    Survey data is used to estimate the impact of physical attractiveness rated by the interviewer as well as by the respondent on employment probability and labor income of men and women. In addition to mean linear and non-linear effects on earnings, simultaneous quantile regressions are applied to analyze heterogeneity across the wage distribution.

  9. Comparative analysis of the structure of sterically stabilized ferrofluids on polar carriers by small-angle neutron scattering.

    Science.gov (United States)

    Avdeev, M V; Aksenov, V L; Balasoiu, M; Garamus, V M; Schreyer, A; Török, Gy; Rosta, L; Bica, D; Vékás, L

    2006-03-01

    Results of experiments on small-angle neutron scattering from ferrofluids on polar carriers (pentanol, water, methyl-ethyl-ketone), with double-layer sterical stabilization of magnetic nanoparticles, are reported. Several types of spatial structural organization are observed. The structure of highly stable pentanol-based samples is similar to that of stable ferrofluids based on organic non-polar carriers (e.g., benzene) with mono-layer covered magnetic nanoparticles. At the same time, the effect of the interparticle interaction on the scattering is stronger in polar ferrofluids because of the structural difference in the surfactant shell. The structure of the studied methyl-ethyl-ketone- and water-based ferrofluids essentially different from the previous case. The formation of large (>100 nm in size) elongated or fractal aggregates, respectively, is detected even in the absence of external magnetic field, which corresponds to weaker stability of these types of ferrofluids. The structure of the fractal aggregates in water-based ferrofluids does not depend on the particle concentration, but it is sensitive to temperature. A temperature increase results in a decrease in their fractal dimension reflecting destruction of the aggregates. In addition, in water-based ferrofluids these aggregates consist of small (radius approximately 10 nm) and temperature-stable primary aggregates. PMID:16102775

  10. Tris(triazolyl)borate ligands of intermediate steric bulk for the synthesis of biomimetic structures with hydrogen bonding and solubility in hydrophilic solvents.

    Science.gov (United States)

    Gardner, Sean R; Papish, Elizabeth T; Monillas, Wesley H; Yap, Glenn P A

    2008-12-01

    Tris(triazolyl)borate ligands (Ttz) of intermediate steric bulk were synthesized to investigate their potential for hydrogen bonding and improved solubility in hydrophilic solvents as applied to biomimetic chemistry. The crystal structure of 3-phenyl-5-methyl-1,2,4-triazole (Htz(Ph,Me)) revealed hydrogen bonding and pi stacking interactions. The new ligand salt, potassium tris(3-phenyl-5-methyl-1,2,4-triazolyl)borate (KTtz(Ph,Me)) was synthesized as the first example of a Ttz ligand of intermediate steric bulk. Metathesis between KTtz(Ph,Me) and NaCl followed by recrystallization produced [NaTtz(Ph,Me)].6CH3OH in which the geometry around the sodium is octahedral with an unusual N(3)O(3) donor set; this structure also shows that a hydrogen bonding network is formed by methanol molecules and triazole nitrogens. (Ttz(Ph,Me))ZnCl was synthesized and characterized crystallographically as [(Ttz(Ph,Me))ZnCl].0.5CH3OH in which the zinc is tetrahedral and the triazole rings are within hydrogen bonding distance of CH(3)OH. All of these new compounds are methanol soluble to varying degrees and Htz(Ph,Me) and KTtz(Ph,Me) are soluble in methanol/water mixtures. PMID:18848725

  11. Electrostatic attraction between neutral microdroplets by ion fluctuations

    Science.gov (United States)

    Sheng, Yu-Jane; Tsao, Heng-Kwong

    2004-06-01

    The interaction between two aqueous droplets containing ions is investigated. The ion-fluctuation correlation gives rise to attraction between two neutral microdroplets, similar to the van der Waals interaction between neutral atoms. Electrostatic attraction consists of contributions from various induced multipole-multipole interactions, including dipole-dipole 2 r-6 , dipole-quadrupole r-8 , dipole-octupole zzz > r-10 , and quadrupole-quadrupole interactions 2 r-10 . The mean-square multipole moments are determined analytically by linear response theory. The fluctuation-driven attraction is so strong at short distance that it may dominate over the Coulomb repulsion between like-charged droplets. These theoretical results are confirmed by Monte Carlo simulations.

  12. The role of Argo steric sea level within the global sea level budget

    Science.gov (United States)

    von Schuckmann, K.; Sallée, J.-B.; Cabanes, C.; Le Traon, P.-Y.; Gaillard, F.; Speich, S.; Hamon, M.

    2012-04-01

    Precise estimations of global ocean indicators (GOIs) such as global ocean heat content (GOHC) and global steric sea level (GSSL) are necessary to observe the ocean's role in the Earth's climate system. To improve accuracy of these estimations, our knowledge of deep ocean and regional contributions to GOIs needs to be quantified. Data from the global Argo array are used here to analyze these contributionsduring the period 2005 to 2010. GOHC/GMSH rise increases by 25% /35% for the upper 2000m depth compared to the upper ocean 700m depth. A comparison of Argo steric sea level to total sea level from satellite altimetry (AVISO) and ocean mass (GRACE) is performed during this period. We could close the global and regional sea level budgets for 2005 to 2010 in terms of 6-year trends. Results show that largest correlation of global GSSL, ocean mass and global total sea level can be observed in the global tropical basin. Differences of the 6-year trend between global mean total sea level and GSSL in this basin are mostly explained by Argo sampling issues, especially in the - by Argo under sampled - Indonesian Archipelago. The differences of the 6-year trend in the Southern Ocean can be attributed to mass changes and deep ocean steric changes, whereas in the Northern Ocean mass changes clearly dominate decadal and longer-term variability. The results are only valid under the assumption that no systematic errors remain in either one of the global observing systems, although the comparison of all three observing systems indicates that these errors appear to be small during the years 2005 to 2010.

  13. An Analysis of the Steric Sea Level Change by Introducing Sea Surface Temperature

    Institute of Scientific and Technical Information of China (English)

    SUN Ruili; LI Lei; LI Peiliang

    2013-01-01

    In this paper,we use the optimum interpolation sea surface temperature (OISST) provided by the National Center for Environmental Prediction (NCEP) to replace the temperature in the top three layers in the ISHII data,and make use of the modified ISHII temperature data to calculate the thermosteric sea level (called modified steric sea level (SSL) hereafter).We subtract the modified SSL and the steric sea level (called ordinary SSL hereafter) derived from the ISHII temperature and salinity from the steric sea level (SSL) provided by the Gravity Recovery and Climate Experiment (GRACE),respectively,and find that the rms error of the difference of the former is obviously smaller than that of the latter.Therefore we reach the conclusion that under the assumption that the GRACE SSL is accurate,the modified SSL can reflect the true steric sea level more accurately.Making use of the modified SSL,we can find that the modified SSL in sea areas of different spatial scales shows an obvious rising trend in the upper 0-700 m layer for the period 1982-2006.The global mean SSL rises with a rate of 0.6 mm year-1.The modified SSLs in sea areas of different spatial scales all show obvious oscillations with period of one year.There are oscillations with periods of 4-8 years in global oceans and with periods of 2-7 years in the Pacific.The Empirical Orthogonal Function method is applied to the sea areas of different spatial scales and we find that the first modes all have obvious 1-year period oscillations,the first mode of the global ocean has 4-8 year period oscillations,and that of the Pacific has 2-6 year period oscillations.The spatial distribution of the linear rising trend of the global modified SSL in the upper 0-700 m layer is inhomogeneous with intense regional characteristics.The modified SSL linear trend indicates a zonal dipole in the tropical Pacific,rising in the west and descending in the east.In the North Atlantic,the modified SSL indicates a meridional dipole,rising in

  14. Particle vs. pair condensation in attractive Bose liquids

    OpenAIRE

    Nozières, P.; Saint James, D.

    1982-01-01

    The competition between particle and pair condensation in Bose liquids is studied using a mean field variational ground state that comprises both the Bogoliubov approximation for weakly interacting Bose gases and the Valatin-Butler pair state. We first consider structureless bosons, disregarding the fact that an attractive gas will necessarily collapse. We show that a pair state occurs only if the attraction is strong enough to bind two bosons together. The limit of low densities is treated e...

  15. Different Vocal Parameters Predict Perceptions of Dominance and Attractiveness

    OpenAIRE

    Hodges-Simeon, Carolyn R.; Gaulin, Steven J.; Puts, David A.

    2010-01-01

    Low mean fundamental frequency (F 0) in men’s voices has been found to positively influence perceptions of dominance by men and attractiveness by women using standardized speech. Using natural speech obtained during an ecologically valid social interaction, we examined relationships between multiple vocal parameters and dominance and attractiveness judgments. Male voices from an unscripted dating game were judged by men for physical and social dominance and by women in fert...

  16. Effective interactions between fluid membranes

    CERN Document Server

    Lu, Bing-Sui

    2016-01-01

    A self-consistent theory is proposed for the general problem of interacting undulating fluid membranes subject to the constraint that they do not interpenetrate. We implement the steric constraint via an exact functional integral representation, and through the use of a saddle-point approximation transform it into a novel effective steric potential. The steric potential is found to consist of two contributions: one generated by zero mode fluctuations of the membranes, and the other by thermal bending fluctuations. For membranes of cross-sectional area $S$, we find that the bending fluctuation part scales with the inter-membrane separation $d$ as $d^{-2}$ for $d \\ll \\sqrt{S}$, but crosses over to $d^{-4}$ scaling for $d \\gg \\sqrt{S}$, whereas the zero mode part of the steric potential always scales as $d^{-2}$. For membranes interacting exclusively via the steric potential, we obtain closed-form expressions for the effective interaction potential and for the rms undulation amplitude $\\sigma$, which becomes sma...

  17. Modelling of electron beam induced nanowire attraction

    Science.gov (United States)

    Bitzer, Lucas A.; Speich, Claudia; Schäfer, David; Erni, Daniel; Prost, Werner; Tegude, Franz J.; Benson, Niels; Schmechel, Roland

    2016-04-01

    Scanning electron microscope (SEM) induced nanowire (NW) attraction or bundling is a well known effect, which is mainly ascribed to structural or material dependent properties. However, there have also been recent reports of electron beam induced nanowire bending by SEM imaging, which is not fully explained by the current models, especially when considering the electro-dynamic interaction between NWs. In this article, we contribute to the understanding of this phenomenon, by introducing an electro-dynamic model based on capacitor and Lorentz force interaction, where the active NW bending is stimulated by an electromagnetic force between individual wires. The model includes geometrical, electrical, and mechanical NW parameters, as well as the influence of the electron beam source parameters and is validated using in-situ observations of electron beam induced GaAs nanowire (NW) bending by SEM imaging.

  18. Facial attractiveness: evolutionary based research.

    Science.gov (United States)

    Little, Anthony C; Jones, Benedict C; DeBruine, Lisa M

    2011-06-12

    Face preferences affect a diverse range of critical social outcomes, from mate choices and decisions about platonic relationships to hiring decisions and decisions about social exchange. Firstly, we review the facial characteristics that influence attractiveness judgements of faces (e.g. symmetry, sexually dimorphic shape cues, averageness, skin colour/texture and cues to personality) and then review several important sources of individual differences in face preferences (e.g. hormone levels and fertility, own attractiveness and personality, visual experience, familiarity and imprinting, social learning). The research relating to these issues highlights flexible, sophisticated systems that support and promote adaptive responses to faces that appear to function to maximize the benefits of both our mate choices and more general decisions about other types of social partners. PMID:21536551

  19. Fingertip aura and interpersonal attraction.

    Science.gov (United States)

    Murstein, B I; Hadjolian, S E

    1977-06-01

    Concluding from our survey of the literature that fingertip auras (Kirlian effect) might be associated with interpersonal attraction, four hypotheses were advanced to test this assertion. It was hypothesized that individuals would respond with bigger auras to (1) opposite-sex photographers as compared to same-sex photographers, (2) to seductive opposite-sex photographers as opposed to normally behaving opposite-sex photographers, (3) to opposite-sex unknown peers as opposed to same-sex unknown peers, and (4) to liked as opposed to disliked same-sex persons. All hypotheses except (2) were supported. The second hypothesis was significant in a direction contrary to hypothesis. Fingertip auras are seen as a promising measurement device in the study of interpersonal attraction. PMID:16367230

  20. Facial attractiveness: evolutionary based research

    OpenAIRE

    Little, Anthony C.; Jones, Benedict C.; DeBruine, Lisa M

    2011-01-01

    Face preferences affect a diverse range of critical social outcomes, from mate choices and decisions about platonic relationships to hiring decisions and decisions about social exchange. Firstly, we review the facial characteristics that influence attractiveness judgements of faces (e.g. symmetry, sexually dimorphic shape cues, averageness, skin colour/texture and cues to personality) and then review several important sources of individual differences in face preferences (e.g. hormone levels ...

  1. Elaboration of Sterically Stabilized Liposomes for S-Nitrosoglutathione Targeting to Macrophages.

    Science.gov (United States)

    Diab, R; Virriat, A S; Ronzani, C; Fontanay, S; Grandemange, S; Elaissari, A; Foliguet, B; Maincent, P; Leroy, P; Duvaj, R E; Rihn, B H; Joubert, O

    2016-01-01

    S-nitrosoglutathione (GSNO) is a potential therapeutic for infectious disease treatment because of its pivotal role in macrophage-mediated inflammatory responses and host defense in addition to direct antibacterial activities. In this study, sterically stabilized cationic liposomes (SSCL) and sterically stabilized anionic liposomes (SSAL) were developed as nanocarriers for macrophage targeting. Elaborated liposomes were characterized in terms of size, zeta potential, morphology, encapsulation efficiency, in vitro drug release behavior and cytotoxicity. Their versatility in targeting monocytes/macrophages was determined by confocal laser scanning microscopy and transmission electron microscopy. Flow cytometry revealed that cellular uptake of both SSCL and SSAL was governed by several endocytic clathrin- and caveolae-dependent mechanisms. Quantitative assessments of intracellular nitric oxide demonstrated highly efficient uptake of GSNO-loaded SSCL that was twenty-fold higher than that of GSNO-free molecules. GSNO-loaded SSCL displayed strong bacteriostatic effects on Staphylococcus aureus and Pseudomonas aeruginosa, which can be involved in pulmonary infectious diseases. These results reveal the potential of liposomal GSNO as an anti-infective therapeutic due to its macrophage targeting capacity and direct antibacterial effects. PMID:27301185

  2. Steric Stabilization of “Charge-Free” Cellulose Nanowhiskers by Grafting of Poly(ethylene glycol

    Directory of Open Access Journals (Sweden)

    Jun Araki

    2014-12-01

    Full Text Available A sterically stabilized aqueous suspension of “charge-free” cellulose nanowhiskers was prepared by hydrochloric acid hydrolysis of cotton powders and subsequent surface grafting of monomethoxy poly(ethylene glycol (mPEG. The preparation scheme included carboxylation of the terminal hydroxyl groups in mPEG via oxidation with silica gel particles carrying 2,2,6,6-tetramethyl-1-pyperidinyloxyl (TEMPO moieties and subsequent esterification between terminal carboxyls in mPEG and surface hydroxyl groups of cellulose nanowhiskers, mediated by 1,1'-carbonyldiimidazole (CDI in dimethyl sulfoxide or dimethylacetamide. Some of the prepared PEG-grafted samples showed remarkable flow birefringence and enhanced stability after 24 h, even in 0.1 M NaCl, suggesting successful steric stabilization by efficient mPEG grafting. Actual PEG grafting via ester linkages was confirmed by attenuated total reflectance-Fourier transform infrared spectrometry. In a typical example, the amount of grafted mPEG was estimated as ca. 0.3 g/g cellulose by two measurements, i.e., weight increase after grafting and weight loss after alkali cleavage of ester linkages. Transmission electron microscopy indicated unchanged nanowhisker morphology after mPEG grafting.

  3. From soft to hard rod behavior in liquid crystalline suspensions of sterically stabilized colloidal filamentous particles.

    Science.gov (United States)

    Grelet, Eric; Rana, Richa

    2016-05-18

    The liquid crystalline phase behavior of a colloidal system of sterically stabilized rods is reported. Our colloidal suspensions consist of highly monodisperse, semi-flexible filamentous viruses which have been coated with neutral hydrophilic polymers by irreversibly binding poly(ethylene glycol) (PEG) to the surface of the virus particles. Depending on the size of the grafted polymer, up to three different phase transitions are observed (isotropic-to-chiral nematic, chiral nematic-to-smectic, and smectic-to-columnar). Each phase transition is shown to be independent of ionic strength, confirming the steric stabilization of the viral colloids. A direct, i.e. without any free parameters, comparison with theory and computer simulations of the volume fraction associated with the phase transition can be performed, showing a quantitative agreement with hard rod behavior at a low polymer chain size, and some deviation stemming from soft repulsion by increasing the polymer thickness coating of the rod. Specifically, we demonstrate that the columnar mesophase is not stabilized by electrostatic repulsion, and we discuss the conditions of its existence. PMID:27108523

  4. Temporal and steric analysis of ionic permeation and binding in SERCA via molecular dynamic simulations.

    Science.gov (United States)

    Fonseca, J E; Kaya, S; Rakowski, R F

    2007-10-24

    The availability of the crystal structure of the sarco(endo)plasmic reticulum calcium ATPase (SERCA) has allowed atomic-level molecular dynamic (MD) simulations of this membrane transport protein to be done. The biomedical and nanotechnological implications of this work are discussed as well as the methods of performing the simulations and analysis. We have performed nanosecond timescale simulations of SERCA for several of its known conformations in a lipid/water environment. One simulation contained Ca(2+) ions, while others without ions were analyzed by techniques such as steric pathway determination. We discuss details of the resulting putative cytoplasmic and lumenal pathways, along with experimental evidence from the literature to support our conclusions. Finally, we give a brief overview of future research directions, as they pertain to MD simulations and their analysis. The methodology used in this work shows that significant insight into the structure-function relationship of ion-motive transmembrane pumps can be derived by a combination of simulation tools and analysis techniques including MD trajectories, steric analysis and electrostatic potentials. PMID:21730455

  5. Attractiveness and Leader Style: Evaluations of Male and Female Leaders by Male and Female Evaluators.

    Science.gov (United States)

    Sopasakis, Maria; Snodgrass, Sara E.

    Previous research has suggested that men are stereotypically believed to be better leaders than women; that more physically attractive people are evaluated more positively than less attractive people; and that men and women use different leadership styles. This study examined the interactions of sex, leader style, and physical attractiveness on…

  6. Effects of Applicant Sex, Physical Attractiveness, and Type of Job on Employment Interviewers' Decisions.

    Science.gov (United States)

    Gilmore, David C.; And Others

    Past research on the employment interview has suggested that interviewers are influenced by many variables, including physical attractiveness. To investigate the potential interaction of applicant sex and attractiveness on hiring decisions, the type of job, applicant sex, and applicant physical attractiveness were manipulated to determine the…

  7. Branner-Hubbard Motions and attracting dynamics

    DEFF Research Database (Denmark)

    Petersen, Carsten Lunde; Tan, Lei

    2006-01-01

    We introduce a new notion of attracting dynamics, which is related to polynomial-like mappings. Also we review the Branner-Hubbard Motion and study its action on attracting dynamics.......We introduce a new notion of attracting dynamics, which is related to polynomial-like mappings. Also we review the Branner-Hubbard Motion and study its action on attracting dynamics....

  8. Statistical thermodynamics of membrane bending mediated protein-protein attraction

    OpenAIRE

    Chou, Tom; Kim, Ken S.; Oster, George

    1999-01-01

    Integral membrane proteins deform the surrounding bilayer creating long-ranged forces that influence distant proteins. These forces can be attractive or repulsive, depending on the proteins' shape, height, contact angle with the bilayer, as well as the local membrane curvature. Although interaction energies are not pairwise additive, for sufficiently low protein density, thermodynamic properties depend only upon pair interactions. Here, we compute pair interaction potentials and entropic cont...

  9. Attracting Principals to the Superintendency

    Directory of Open Access Journals (Sweden)

    Aimee Howley

    2002-10-01

    Full Text Available Responding to a perceived shortage of school superintendents in Ohio as well as elsewhere in the nation, this study examined the conditions of the job that make it attractive or unattractive as a career move for principals. The researchers surveyed a random sample of Ohio principals, receiving usable responses from 508 of these administrators. Analysis of the data revealed that principals perceived the ability to make a difference and the extrinsic motivators (e.g., salary and benefits associated with the superintendency as conditions salient to the decision to pursue such a job. Furthermore, they viewed the difficulties associated with the superintendency as extremely important. Among these difficulties, the most troubling were: (1 increased burden of responsibility for local, state, and federal mandates; (2 need to be accountable for outcomes that are beyond an educator’s control; (3 low levels of board support, and (4 excessive pressure to perform. The researchers also explored the personal and contextual characteristics that predisposed principals to see certain conditions of the superintendency as particularly attractive or particularly troublesome. Only two such characteristics, however, proved to be predictive: (1 principals with fewer years of teaching experience were more likely than their more experienced counterparts to rate the difficulty of the job as important to the decision to pursue a position as superintendent, and (2 principals who held cosmopolitan commitments were more likely than those who did not hold such commitments to view the salary and benefits associated with the superintendency as important. Findings from the study provided some guidance to those policy makers who are looking for ways to make the superintendency more attractive as a career move for principals. In particular, the study suggested that policy makers should work to design incentives that address school leaders’ interest in making a difference at the

  10. Economics of attracting new talent

    Energy Technology Data Exchange (ETDEWEB)

    Annan, R.H.

    1984-05-01

    The U.S. photovoltaics industry is rapidly expanding. Because of its high-technology nature, the industry places demands on technical manpower supply. If the U.S. photovoltaics industry is to maintain its world dominance, steps must be taken to insure that these manpower needs, as well as the demand for innovative ideas, are met. This paper explores approaches for attracting more and better technical expertise to photovoltaics. It examines problems facing U.S. education which could lead to the demise of U.S. leadership in all industries. Actions which can be taken by government, industry and academia are also presented.

  11. The effects of facial adiposity on attractiveness and perceived leadership ability

    OpenAIRE

    Re, Daniel Edward; Perrett, David Ian

    2014-01-01

    Facial attractiveness has a positive influence on electoral success both in experimental paradigms and in the real world. One parameter that influences facial attractiveness and social judgements is facial adiposity (a facial correlate to body mass index, BMI). Overweight people have high facial adiposity and are perceived to be less attractive and lower in leadership ability. Here, we used an interactive design in order to assess whether the most attractive level of facial adiposity is also ...

  12. Non-equilibrium tuning of attractive colloidal gels

    Science.gov (United States)

    Boromand, Arman; Maia, Joao

    2015-11-01

    In colloidal gel systems, the presence of multiple interactions in multiple length scales such as Van der Waals, depletion attractions, and electrostatic repulsions makes these systems challenging from both experimental and simulation aspects. Recently, there has been growing interest to tune and manipulate the structural and dynamics properties of those systems without adjusting interparticle interactions, just by taking them out of equilibrium. In this work, we used Core-Modified Dissipative Particle Dynamics (CM-DPD) with a modified depletion potential, as a coarse-grain model to address the gel formation process in short ranged-attractive colloidal suspensions for a range of volume fractions and attraction strengths. It is suggested that at high volume fractions and near the glass transition, there is a transformation from non-bonded glass to bonded-glass for which that the effect of topological frustration (caging) will be alleviated by the presence of attractive potentials (bonding) i.e. melting during cooling. In the first part of the presentation, we discuss our similar findings for semi-dilute volume fraction of attractive bimodal colloidal gels at equilibrium, which can be explained through local densification of attractive colloidal gels. In the second part, structural and dynamics properties of arrested gels will be studied under shear and after cessation of shear to study how the different flow profiles and history will alter final morphology of the gel systems.

  13. Implicitly perceived vocal attractiveness modulates prefrontal cortex activity.

    Science.gov (United States)

    Bestelmeyer, Patricia E G; Latinus, Marianne; Bruckert, Laetitia; Rouger, Julien; Crabbe, Frances; Belin, Pascal

    2012-06-01

    Social interactions involve more than "just" language. As important is a more primitive nonlinguistic mode of communication acting in parallel with linguistic processes and driving our decisions to a much higher degree than is generally suspected. Amongst the "honest signals" that influence our behavior is perceived vocal attractiveness. Not only does vocal attractiveness reflect important biological characteristics of the speaker, it also influences our social perceptions according to the "what sounds beautiful is good" phenomenon. Despite the widespread influence of vocal attractiveness on social interactions revealed by behavioral studies, its neural underpinnings are yet unknown. We measured brain activity while participants listened to a series of vocal sounds ("ah") and performed an unrelated task. We found that voice-sensitive auditory and inferior frontal regions were strongly correlated with implicitly perceived vocal attractiveness. While the involvement of auditory areas reflected the processing of acoustic contributors to vocal attractiveness ("distance to mean" and spectrotemporal regularity), activity in inferior prefrontal regions (traditionally involved in speech processes) reflected the overall perceived attractiveness of the voices despite their lack of linguistic content. These results suggest the strong influence of hidden nonlinguistic aspects of communication signals on cerebral activity and provide an objective measure of this influence. PMID:21828348

  14. "Like-charge attraction" between anionic polyelectrolytes: molecular dynamics simulations.

    Science.gov (United States)

    Molnar, Ferenc; Rieger, Jens

    2005-01-18

    "Like-charge attraction" is a phenomenon found in many biological systems containing DNA or proteins, as well as in polyelectrolyte systems of industrial importance. "Like-charge attraction" between polyanions is observed in the presence of mobile multivalent cations. At a certain limiting concentration of cations, the negatively charged macroions cease to repel each other and even an attractive force between the anions is found. With classical molecular dynamics simulations it is possible to elucidate the processes that govern the attractive behavior with atomistic resolution. As an industrially relevant example we study the interaction of negatively charged carboxylate groups of sodium polyacrylate molecules with divalent cationic Ca2+ counterions. Here we show that Ca2+ ions initially associate with single chains of polyacrylates and strongly influence sodium ion distribution; shielded polyanions approach each other and eventually "stick" together (precipitate), contrary to the assumption that precipitation is initially induced by intermolecular Ca2+ bridging. PMID:15641856

  15. Steric and allosteric effects of fatty acids on the binding of warfarin to human serum albumin revealed by molecular dynamics and free energy calculations.

    Science.gov (United States)

    Fujiwara, Shin-Ichi; Amisaki, Takashi

    2011-01-01

    Human serum albumin (HSA) binds with drugs and fatty acids (FAs). This study was initiated to elucidate the relationship between the warfarin binding affinity of HSA and the positions of bound FA molecules. Molecular dynamics simulations of 11 HSA-warfarin-myristate complexes were performed. HSA-warfarin binding free energy was then calculated for each of the complexes by the molecular mechanics-Poisson-Boltzmann surface area (MM-PBSA) method. The results indicated that the magnitude of the binding free energy was smaller in HSA-warfarin complexes that had 4 or more myristate molecules than in complexes with no myristate molecules. The unfavorable effect on the HSA-warfarin binding affinity was caused sterically by the binding of a myristate molecule to the FA binding site closest to the warfarin binding site. On the other hand, the magnitude of HSA-warfarin binding free energy was largest when 3 myristate molecules were bound to the high-affinity sites. The strongest HSA-warfarin binding was attributable to favorable entropic contribution related to larger atomic fluctuations of the amino acid residues at the warfarin binding site. In the binding of 2 myristate molecules to the sites with the highest and second-highest affinities, allosteric modulation that enhanced electrostatic interactions between warfarin and some of the amino acid residues around the warfarin binding site was observed. This study clarified the structural and energetic properties of steric/allosteric effects of FAs on the HSA-warfarin binding affinity and illustrated the approach to analyze protein-ligand interactions in situations such that multiple ligands bind to the other sites of the protein. PMID:21720037

  16. On the steric and mass-induced contributions to the annual sea level variations in the Mediterranean Sea

    OpenAIRE

    Garcia-Garcia, David; Chao, Benjamin F.; Río, Jorge del; Vigo Aguiar, Isabel; García-Lafuente, Jesús

    2006-01-01

    The sea level variation (SLVtotal) is the sum of two major contributions: steric and mass-induced. The steric SLVsteric is that resulting from the thermal and salinity changes in a given water column. It only involves volume change, hence has no gravitational effect. The mass-induced SLVmass, on the other hand, arises from adding or subtracting water mass to or from the water column and has direct gravitational signature. We examine the closure of the seasonal SLV budget and estimate the rela...

  17. Structural organization of water-based ferrofluids with sterical stabilization as revealed by SANS

    Energy Technology Data Exchange (ETDEWEB)

    Balasoiu, M. [Institute of Space Sciences, Bucharest (Romania) and Frank Laboratory of Neutron Physics, Joint Institute for Nuclear Research, Dubna (Russian Federation)]. E-mail: balasoiumaria@yahoo.com; Avdeev, M.V. [Frank Laboratory of Neutron Physics, Joint Institute for Nuclear Research, Dubna (Russian Federation); Lomonosov Moscow State University (Russian Federation); Aksenov, V.L. [Frank Laboratory of Neutron Physics, Joint Institute for Nuclear Research, Dubna (Russian Federation); Lomonosov Moscow State University (Russian Federation); Hasegan, D. [Institute of Space Sciences, Bucharest (Romania); Garamus, V.M. [GKSS Research Centre, Geesthacht (Germany); Schreyer, A. [GKSS Research Centre, Geesthacht (Germany); Bica, D. [Center for Fundamental and Advanced Technical Research, Timisoara (Romania); Vekas, L. [Center for Fundamental and Advanced Technical Research, Timisoara (Romania)

    2006-05-15

    Small-angle neutron scattering (SANS) with contrast variation is applied to reveal structural organization of a water-based ferrofluid where magnetite nanoparticles are sterically stabilized by the double layer of dodecylbenzenesulphonic acid (DBS). The contrast is changed by the use of different ratios between light and heavy water in the carrier. The modified basic functions are introduced and determined following the analysis of the shape scattering from the colloidal particles in the fluid. Three types of particles are detected, which are presumably initial particles (size {approx}20 nm), secondary fractal aggregates (size >250 nm) and micelles of DBS (size {approx}5 nm). The found effective match point (35% of D{sub 2}O) gives the 26 vol% content of magnetite in the initial particles.

  18. Effect of Structural Modifications on the Self-Assembly of Oligoprolines Conjugated with Sterically Demanding Chromophores.

    Science.gov (United States)

    Lewandowska, Urszula; Zajaczkowski, Wojciech; Pisula, Wojciech; Ma, Yingjie; Li, Chen; Müllen, Klaus; Wennemers, Helma

    2016-03-01

    Conjugates between oligoprolines and sterically demanding perylene monoimides (PMIs) form hierarchical supramolecular self-assemblies. The influence of the length and stereochemistry at the attachment site between the peptide backbone and the chromophore on the self-assembly properties of the conjugates was explored. Comparison between oligoprolines bearing 4R- or 4S-configured azidoprolines (Azp) for the conjugation with the PMIs revealed that diastereoisomers with 4R configuration guide the self-assembly consistently better than conjugates with 4S configuration. Elongating the peptide chain beyond nine proline residues or introducing structural "errors", by altering the absolute configuration of one stereogenic center at the outside of the functionalizable oligoproline helix, lowered the efficacy of self-assembly significantly, both in solution phase and in the solid state. The results showed how subtle structural modifications allow for tuning the self-assembly of chromophores and provided further design principles for the development of peptide-chromophore conjugates into nanostructured materials. PMID:26891419

  19. Earliest local emergence of forced dynamic and steric sea-level trends in climate models

    International Nuclear Information System (INIS)

    We investigate the impact of internal variability on the emergence of a forced local trend in steric and dynamic sea surface height in historical and future climate simulations. By analyzing the unforced control simulations, the magnitude of internally generated, local trends in sea surface height is quantified and compared to trends found in historical simulations and projections. We find that the timing of the emergence of a forced local signal depends strongly on the location and the year in which the trend computations are started. Starting in 1950, it takes at least 60 yr to detect a forced trend in regions of weak internal variability such as the tropical Atlantic Ocean while this period is reduced to 30 yr when starting in 1990. The detection of a forced trend is further delayed by several decades in regions of elevated internal variability. (letter)

  20. Sign of the state-to-state steric asymmetry of rotationally inelastic atom-molecule collisions

    International Nuclear Information System (INIS)

    The sign of the theoretically predicted steric asymmetry S in rotational inelastic state resolved molecule-atom collisions is questioned. It is shown that the sign of the T-matrix obtained on a basis of non-oriented rotational states of the molecule depends on the choice of the Jacobi coordinates in which the collision problem is solved. Explicit expressions for the state-to-state dependence of the integral and differential cross-sections for oriented and non-oriented molecules are presented. The effect of the choice of Jacobi angles and the inertial frame of reference on the sign of S are discussed in detail. The sign of the earliest obtained expression for the steric asymmetry of the integral cross-section (as reported by van Leuken et al.) is found to be correct, whereas that of the orientational-dependent contribution of the differential cross-section (as reported by Alexander and Stolte) requires a negative multiplication factor. Quantum mechanical calculations on collisions of OH with Ar are performed. These calculations do not agree with the experimental sign of S and cannot be interpreted in terms of a simple ball and stick model. Inspection of the HIBRIDON source code shows that the prepared wavefunction carries an orientation that is opposite to the one assumed. This could offer an explanation for the disagreement for S. For collisions of NO with Ar, the signs of the quantum mechanically calculated and the experimental values of S appear to disagree with the simple ball and stick model. The experimental sign of S has been reinvestigated. Previous experimental results are confirmed

  1. Targeted Sterically Stabilized Phospholipid siRNA Nanomedicine for Hepatic and Renal Fibrosis

    Directory of Open Access Journals (Sweden)

    Fatima Khaja

    2016-01-01

    Full Text Available Since its discovery, small interfering RNA (siRNA has been considered a potent tool for modulating gene expression. It has the ability to specifically target proteins via selective degradation of messenger RNA (mRNA not easily accessed by conventional drugs. Hence, RNA interference (RNAi therapeutics have great potential in the treatment of many diseases caused by faulty protein expression such as fibrosis and cancer. However, for clinical application siRNA faces a number of obstacles, such as poor in vivo stability, and off-target effects. Here we developed a unique targeted nanomedicine to tackle current siRNA delivery issues by formulating a biocompatible, biodegradable and relatively inexpensive nanocarrier of sterically stabilized phospholipid nanoparticles (SSLNPs. This nanocarrier is capable of incorporating siRNA in its core through self-association with a novel cationic lipid composed of naturally occuring phospholipids and amino acids. This overall assembly protects and delivers sufficient amounts of siRNA to knockdown over-expressed protein in target cells. The siRNA used in this study, targets connective tissue growth factor (CTGF, an important regulator of fibrosis in both hepatic and renal cells. Furthermore, asialoglycoprotein receptors are targeted by attaching the galactosamine ligand to the nanocarries which enhances the uptake of nanoparticles by hepatocytes and renal tubular epithelial cells, the major producers of CTGF in fibrosis. On animals this innovative nanoconstruct, small interfering RNA in sterically stabilized phospholipid nanoparticles (siRNA-SSLNP, showed favorable pharmacokinetic properties and accumulated mostly in hepatic and renal tissues making siRNA-SSLNP a suitable system for targeting liver and kidney fibrotic diseases.

  2. A group's physical attractiveness is greater than the average attractiveness of its members : The group attractiveness effect

    NARCIS (Netherlands)

    van Osch, Y.M.J.; Blanken, Irene; Meijs, Maartje H. J.; van Wolferen, Job

    2015-01-01

    We tested whether the perceived physical attractiveness of a group is greater than the average attractiveness of its members. In nine studies, we find evidence for the so-called group attractiveness effect (GA-effect), using female, male, and mixed-gender groups, indicating that group impressions of

  3. A covalent attraction between two molecular cation TTF·~+

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    The optimized structure of the tetrathiafulvalence radical-cation dimer(TTF·+-TTF·+) with all-real frequencies is obtained at MP2/6-311G level,which exhibits the attraction between two molecular cation TTF·+.The new attraction interaction is a 20-center-2-electron intermolecular covalent π /π bonding with a telescope shape.The covalent π /π bonding has the bonding energy of about -21 kcal·mol-1 and is concealed by the Coulombic repulsion between two TTF·+ cations.This intermolecular covalent attraction also influences the structure of the TTF·+ subunit,i.e.,its molecular plane is bent by an angle θ=5.6°.This work provides new knowledge on intermolecular interaction.

  4. Role of attractive forces in tapping tip force microscopy

    DEFF Research Database (Denmark)

    Kyhle, Anders; Sørensen, Alexis Hammer; Bohr, Jakob

    1997-01-01

    We present experimental and numerical results demonstrating the drastic influence of attractive forces on the behaviour of the atomic force microscope when operated in the resonant tapping tip mode in an ambient environment. It is often assumed that tapping is related to repulsive interaction....... In contrast, we find that in general the attractive forces are the most dominant interaction in this mode of operation. We show that attractive forces in combination with the repulsive elastic type of forces cause points of instability in the parameter space constituted by: the cantilever swing amplitude......, the frequency bias point, and the distance between the fixed end of the cantilever and the sample. These points of instability can result in disturbances during image acquisition on hard elastic surfaces. ©1997 American Institute of Physics....

  5. Interpersonal Congruency, Attitude Similarity, and Interpersonal Attraction

    Science.gov (United States)

    Touhey, John C.

    1975-01-01

    As no experimental study has examined the effects of congruency on attraction, the present investigation orthogonally varied attitude similarity and interpersonal congruency in order to compare the two independent variables as determinants of interpersonal attraction. (Author/RK)

  6. Interpersonal Attraction in Relation to the Loss-Gain Hypothesis.

    Science.gov (United States)

    Sharma, Vandana; Kaur, Inderjeet

    1996-01-01

    Maintains that a loss-gain hypothesis (a negative impression gives way to a positive one) is a more powerful indicator and incentive for future friendship than an opposite sequence (positive to negative). Both of these, however, were eclipsed by a positive-positive interaction as a determinant of interpersonal attraction. (MJP)

  7. Investment attractiveness of Ukraine: problems and solutions

    Directory of Open Access Journals (Sweden)

    Onishchenko Irina

    2016-03-01

    Full Text Available The article describes basic questions of the investment climate and investment attractiveness of Ukraine. Investment Attractiveness Index is analyzed by the methodology of European Business Association. The main advantages of Ukraine that attract foreign investors are revised. The article applies the comprehensive approach to study the problems hindering the increase of investment attractiveness of Ukraine. It determines the ways of solving the problems associated with deterring investment development.

  8. Influence of wetting and dispersing agents on the interaction between talc and hydrophobic particles.

    Science.gov (United States)

    Wallqvist, Viveca; Claesson, Per M; Swerin, Agne; Schoelkopf, Joachim; Gane, Patrick A C

    2009-06-16

    The interactions between a natural talc surface and a model hydrophobic particle have been investigated in aqueous solutions by employing the atomic force microscopy (AFM) colloidal probe technique. The results demonstrate the presence of long-range attractive forces due to bridging via preadsorbed or induced bubbles/cavities. Due to the natural heterogeneity of talc, and the stochastic nature of the bubble bridging process, the variability in the range and magnitude of the attraction is larger than that for cases when other interactions predominate or than that when only model surfaces are used. Addition of poly(acrylic acid), a common dispersing agent, did not affect the measured forces. Thus, we conclude that poly(acrylic acid) does not adsorb to the basal plane of talc. In sharp contrast, addition of Pluronic PE6400, a nonionic triblock polymer used as wetting agent, resulted in complete removal of the bubble-induced attractive force. Instead, a short-range steric repulsion is the dominating feature. Clearly, Pluronic PE6400 is able to displace air bubbles from the surface and prevent their formation when the particles come into contact. These are suggested to be important features of efficient wetting agents. PMID:19334743

  9. Attribution, the Attractiveness Stereotype, and the Elderly.

    Science.gov (United States)

    Johnson, Douglas F.; Pittenger, John B.

    1984-01-01

    Tests the applicability of the physical attractiveness stereotype to perceptions of the elderly. In the first study, college-age and elderly observers rated the attractiveness of faces of elderly people. In the second study, subjects rated faces at three levels of attractiveness on personality, success in life experiences, and occupational…

  10. A group's physical attractiveness is greater than the average attractiveness of its members: the group attractiveness effect.

    Science.gov (United States)

    van Osch, Yvette; Blanken, Irene; Meijs, Maartje H J; van Wolferen, Job

    2015-04-01

    We tested whether the perceived physical attractiveness of a group is greater than the average attractiveness of its members. In nine studies, we find evidence for the so-called group attractiveness effect (GA-effect), using female, male, and mixed-gender groups, indicating that group impressions of physical attractiveness are more positive than the average ratings of the group members. A meta-analysis on 33 comparisons reveals that the effect is medium to large (Cohen's d = 0.60) and moderated by group size. We explored two explanations for the GA-effect: (a) selective attention to attractive group members, and (b) the Gestalt principle of similarity. The results of our studies are in favor of the selective attention account: People selectively attend to the most attractive members of a group and their attractiveness has a greater influence on the evaluation of the group. PMID:25733515

  11. The effects of facial adiposity on attractiveness and perceived leadership ability.

    Science.gov (United States)

    Re, Daniel E; Perrett, David I

    2014-01-01

    Facial attractiveness has a positive influence on electoral success both in experimental paradigms and in the real world. One parameter that influences facial attractiveness and social judgements is facial adiposity (a facial correlate to body mass index, BMI). Overweight people have high facial adiposity and are perceived to be less attractive and lower in leadership ability. Here, we used an interactive design in order to assess whether the most attractive level of facial adiposity is also perceived as most leader-like. We found that participants reduced facial adiposity more to maximize attractiveness than to maximize perceived leadership ability. These results indicate that facial appearance impacts leadership judgements beyond the effects of attractiveness. We suggest that the disparity between optimal facial adiposity in attractiveness and leadership judgements stems from social trends that have produced thin ideals for attractiveness, while leadership judgements are associated with perception of physical dominance. PMID:23971489

  12. Acid-base cooperativity of heterogeneous catalyst containing acidic framework and sterically hindered base for aldol condensation

    Institute of Scientific and Technical Information of China (English)

    Hua Li; Shu Tao Xu; Xiao Bing Lu; Wei Ping Zhang

    2009-01-01

    A bifunctional heterogeneous catalyst containing two mutually incompatible acidic and basic sites,which exhibits cooperative catalytic behavior in the aldol condensation of acetone and various aldehydes,was synthesized by postgrafting of 1,5,7-triazabicyclo[4.4.0]dec-5-ene(TBD,a sterically hindered organic base)onto Al-MCM-41 molecular sieve.

  13. Comment on "Rabbit-Ears Hybrids, VSEPR Sterics, and Other Orbital Anachronisms": A Reply to a Criticism

    Science.gov (United States)

    Hiberty, Philippe C.; Danovich, David; Shaik, Sason

    2015-01-01

    This commentary summarizes the authors' basic disagreements with the paper, "Rabbit-Ears, VSEPR Sterics, and Other Orbital Anachronisms," which criticizes the authors' usage of the hybrid orbitals for H[subscript 2]O in their book, "A Chemist's Guide to Valence Bond Theory" (Shaik and Hiberty, 2008). The current article shows…

  14. Steric effects on the primary isotope dependence of secondary kinetic isotope effects in hydride transfer reactions in solution: caused by the isotopically different tunneling ready state conformations?

    Science.gov (United States)

    Maharjan, Binita; Raghibi Boroujeni, Mahdi; Lefton, Jonathan; White, Ormacinda R; Razzaghi, Mortezaali; Hammann, Blake A; Derakhshani-Molayousefi, Mortaza; Eilers, James E; Lu, Yun

    2015-05-27

    The observed 1° isotope effect on 2° KIEs in H-transfer reactions has recently been explained on the basis of a H-tunneling mechanism that uses the concept that the tunneling of a heavier isotope requires a shorter donor-acceptor distance (DAD) than that of a lighter isotope. The shorter DAD in D-tunneling, as compared to H-tunneling, could bring about significant spatial crowding effect that stiffens the 2° H/D vibrations, thus decreasing the 2° KIE. This leads to a new physical organic research direction that examines how structure affects the 1° isotope dependence of 2° KIEs and how this dependence provides information about the structure of the tunneling ready states (TRSs). The hypothesis is that H- and D-tunneling have TRS structures which have different DADs, and pronounced 1° isotope effect on 2° KIEs should be observed in tunneling systems that are sterically hindered. This paper investigates the hypothesis by determining the 1° isotope effect on α- and β-2° KIEs for hydride transfer reactions from various hydride donors to different carbocationic hydride acceptors in solution. The systems were designed to include the interactions of the steric groups and the targeted 2° H/D's in the TRSs. The results substantiate our hypothesis, and they are not consistent with the traditional model of H-tunneling and 1°/2° H coupled motions that has been widely used to explain the 1° isotope dependence of 2° KIEs in the enzyme-catalyzed H-transfer reactions. The behaviors of the 1° isotope dependence of 2° KIEs in solution are compared to those with alcohol dehydrogenases, and sources of the observed "puzzling" 2° KIE behaviors in these enzymes are discussed using the concept of the isotopically different TRS conformations. PMID:25941865

  15. Unique Attractions in Jane Eyre

    Institute of Scientific and Technical Information of China (English)

    刘莉

    2008-01-01

    从三个方面分析了世界文学名著为什么至今仍充满着强大而独特的魅力:一、作品自传的成分很大,具有真实性和感染力;二、夏洛蒂·勃朗特是英国文学史上第一个明确将女性的呼声作为小说主题的人;三、基督教的平等自由的思想得到了充分的体现,更表达了夏洛蒂蕴藏的独特的宗教观点--神性和人性的结合.%The writer explains why Jane Eyre, as a masterpiece of the world literature, is still full of strong and unique attractions? It mainly lies in three aspects: firstly, it is more like a self-biography with authenticity and strong infection power; secondly, Charlotte is the very first writer in English literary history who definitely takes the cry of women as the theme of novel ; lastly, the thinking of freedom and equality in Christianism is fully inflected in the novel, furthermore, Charlotte expresses her implied unique religious idea, that is, combination of divinity and human nature.

  16. High Heels Increase Women's Attractiveness.

    Science.gov (United States)

    Guéguen, Nicolas

    2015-11-01

    Research has found that the appearance of women's apparel helps increase their attractiveness as rated by men and that men care more about physical features in potential opposite-sex mates. However, the effect of sartorial appearance has received little interest from scientists. In a series of studies, the length of women's shoe heels was examined. A woman confederate wearing black shoes with 0, 5, or 9 cm heels asked men for help in various circumstances. In Study 1, she asked men to respond to a short survey on gender equality. In Study 2, the confederate asked men and women to participate in a survey on local food habit consumption. In Study 3, men and women in the street were observed while walking in back of the female confederate who dropped a glove apparently unaware of her loss. It was found that men's helping behavior increased as soon as heel length increased. However, heel length had no effect on women's helping behavior. It was also found that men spontaneously approached women more quickly when they wore high-heeled shoes (Study 4). Change in gait, foot-size judgment, and misattribution of sexiness and sexual intent were used as possible explanations. PMID:25408499

  17. Attracting Girls into Physics (abstract)

    Science.gov (United States)

    Gadalla, Afaf

    2009-04-01

    A recent international study of women in physics showed that enrollment in physics and science is declining for both males and females and that women are severely underrepresented in careers requiring a strong physics background. The gender gap begins early in the pipeline, from the first grade. Girls are treated differently than boys at home and in society in ways that often hinder their chances for success. They have fewer freedoms, are discouraged from accessing resources or being adventurous, have far less exposure to problem solving, and are not encouraged to choose their lives. In order to motivate more girl students to study physics in the Assiut governorate of Egypt, the Assiut Alliance for the Women and Assiut Education District collaborated in renovating the education of physics in middle and secondary school classrooms. A program that helps in increasing the number of girls in science and physics has been designed in which informal groupings are organized at middle and secondary schools to involve girls in the training and experiences needed to attract and encourage girls to learn physics. During implementation of the program at some schools, girls, because they had not been trained in problem-solving as boys, appeared not to be as facile in abstracting the ideas of physics, and that was the primary reason for girls dropping out of science and physics. This could be overcome by holding a topical physics and technology summer school under the supervision of the Assiut Alliance for the Women.

  18. On the modulispace of attracting dynamics

    DEFF Research Database (Denmark)

    Petersen, Carsten Lunde

    An Attracting Dynamics is a triple (f,W,a), where W is an open subset of the R(iemann) S(phere), f is a holomorphic map from W into the RS and a is an attracting periodic point for f. Denote by B(a) the attracted basin of the orbit of a for f. Two attracting dynamics (f,W,a) and (f',W',a') are i...... of B(a). The moduli space for the attracting dynamics (f,W,a) is the space of attractings dynamics (f,W,a') which are hybridly equivalent to (f,W,a). The talk will discuss properties of moduli spaces of different attracting dynamics....

  19. Effects of Instructor Attractiveness on Learning.

    Science.gov (United States)

    Westfall, Richard; Millar, Murray; Walsh, Mandy

    2016-01-01

    Although a considerable body of research has examined the impact of student attractiveness on instructors, little attention has been given to the influence of instructor attractiveness on students. This study tested the hypothesis that persons would perform significantly better on a learning task when they perceived their instructor to be high in physical attractiveness. To test the hypothesis, participants listened to an audio lecture while viewing a photograph of instructor. The photograph depicted either a physically attractive instructor or a less attractive instructor. Following the lecture, participants completed a forced choice recognition task covering material from the lecture. Consistent with the predictions; attractive instructors were associated with more learning. Finally, we replicated previous findings demonstrating the role attractiveness plays in person perception. PMID:27410051

  20. Vortices in Attractive Bose-Einstein Condensates in Two Dimensions

    International Nuclear Information System (INIS)

    The form and stability of quantum vortices in Bose-Einstein condensates with attractive atomic interactions is elucidated. They appear as ring bright solitons, and are a generalization of the Townes soliton to nonzero winding number m. An infinite sequence of radially excited stationary states appear for each value of m, which are characterized by concentric matter-wave rings separated by nodes, in contrast to repulsive condensates, where no such set of states exists. It is shown that robustly stable as well as unstable regimes may be achieved in confined geometries, thereby suggesting that vortices and their radial excited states can be observed in experiments on attractive condensates in two dimensions

  1. Exploring electronic and steric effects on the insertion and polymerization reactivity of phosphinesulfonato pdii catalysts

    KAUST Repository

    Neuwald, Boris

    2013-11-21

    Thirteen different symmetric and asymmetric phosphinesulfonato palladium complexes ([{(X1-Cl)-μ-M}n], M=Na, Li, 1= X(P^O)PdMe) were prepared (see Figure 1). The solid-state structures of the corresponding pyridine or lutidine complexes were determined for (MeO)21-py, (iPrO)21-lut, (MeO,Me2)1-lut, (MeO)31-lut, CF31-lut, and Ph1-lut. The reactivities of the catalysts X1, obtained after chloride abstraction with AgBF4, toward methyl acrylate (MA) were quantified through determination of the rate constants for the first and the consecutive MA insertion and the analysis of β-H and other decomposition products through NMR spectroscopy. Differences in the homo- and copolymerization of ethylene and MA regarding catalyst activity and stability over time, polymer molecular weight, and polar co-monomer incorporation were investigated. DFT calculations were performed on the main insertion steps for both monomers to rationalize the effect of the ligand substitution patterns on the polymerization behaviors of the complexes. Full analysis of the data revealed that: 1) electron-deficient catalysts polymerize with higher activity, but fast deactivation is also observed; 2) the double ortho-substituted catalysts (MeO)21 and (MeO)31 allow very high degrees of MA incorporation at low MA concentrations in the copolymerization; and 3) steric shielding leads to a pronounced increase in polymer molecular weight in the copolymerization. The catalyst properties induced by a given P-aryl (alkyl) moiety were combined effectively in catalysts with two different non-chelating aryl moieties, such as cHexO/(MeO)21, which led to copolymers with significantly increased molecular weights compared to the prototypical MeO1. Catalyst control: The influence of steric and electronic effects on the reactivity of phosphinesulfonato PdII catalysts in polymerization and copolymerization is explored through experimental and DFT methods. A comparison of thirteen different X(P O)PdMe catalysts ((P O)= κ2-P

  2. Attracting young talents to manufacturing

    DEFF Research Database (Denmark)

    Perini, Stefano; Oliveira, Manuel; Costa, Joao;

    2014-01-01

    have been made both in STEM and manufacturing education. However, there is still a lack of concrete strategies harmonizing together delivery mechanisms and pedagogical frameworks throughout the whole student lifecycle. In order to mitigate these urgent needs, ManuSkills innovative approach provides a...... Experiments, Interaction with real companies, Social networks, Challenges and making real products, Career management and skills orientation, are explained in detail with the support of examples of application...

  3. Miscalibrations in judgements of attractiveness with cosmetics.

    Science.gov (United States)

    Jones, Alex L; Kramer, Robin S S; Ward, Robert

    2014-10-01

    Women use cosmetics to enhance their attractiveness. How successful they are in doing so remains unknown--how do men and women respond to cosmetics use in terms of attractiveness? There are a variety of miscalibrations where attractiveness is concerned--often, what one sex thinks the opposite sex finds attractive is incorrect. Here, we investigated observer perceptions about attractiveness and cosmetics, as well as their understanding of what others would find attractive. We used computer graphic techniques to allow observers to vary the amount of cosmetics applied to a series of female faces. We asked observers to optimize attractiveness for themselves, for what they thought women in general would prefer, and what they thought men in general would prefer. We found that men and women agree on the amount of cosmetics they find attractive, but overestimate the preferences of women and, when considering the preferences of men, overestimate even more. We also find that models' self-applied cosmetics are far in excess of individual preferences. These findings suggest that attractiveness perceptions with cosmetics are a form of pluralistic ignorance, whereby women tailor their cosmetics use to an inaccurate perception of others' preferences. These findings also highlight further miscalibrations of attractiveness ideals. PMID:24670156

  4. Potential disruption of protein-protein interactions by graphene oxide

    Science.gov (United States)

    Feng, Mei; Kang, Hongsuk; Yang, Zaixing; Luan, Binquan; Zhou, Ruhong

    2016-06-01

    Graphene oxide (GO) is a promising novel nanomaterial with a wide range of potential biomedical applications due to its many intriguing properties. However, very little research has been conducted to study its possible adverse effects on protein-protein interactions (and thus subsequent toxicity to human). Here, the potential cytotoxicity of GO is investigated at molecular level using large-scale, all-atom molecular dynamics simulations to explore the interaction mechanism between a protein dimer and a GO nanosheet oxidized at different levels. Our theoretical results reveal that GO nanosheet could intercalate between the two monomers of HIV-1 integrase dimer, disrupting the protein-protein interactions and eventually lead to dimer disassociation as graphene does [B. Luan et al., ACS Nano 9(1), 663 (2015)], albeit its insertion process is slower when compared with graphene due to the additional steric and attractive interactions. This study helps to better understand the toxicity of GO to cell functions which could shed light on how to improve its biocompatibility and biosafety for its wide potential biomedical applications.

  5. Steric sea level rise over the Mediterranean Sea: present climate and scenario simulations

    Energy Technology Data Exchange (ETDEWEB)

    Carillo, A.; Sannino, G.; Artale, V.; Ruti, P.M.; Calmanti, S.; Dell' Aquila, A. [ENEA Climate Modeling and Impacts, Rome (Italy)

    2012-11-15

    A regional atmosphere-ocean coupled model has been used to estimate sea level rise in the Mediterranean basin under present and future conditions. A present climate simulation has been forced by ERA40 reanalysis covering the period 1958-2001. Moreover a simulation has been forced by the global coupled model ECHAM5-MPIOM under present climate conditions for the period 1951-2000. Two other 50-year simulations have been performed under the SRESA1B scenario for the twenty-first century and differ only in temperature and salinity profiles used to relax the ocean model in the Atlantic buffer zone. The present climate simulation has been verified in terms of temperature, salinity and sea level against observed data, showing good performances both in mean values and variability over the whole Mediterranean Sea and over different sub-basins. The future scenario simulations show that the steric sea level averaged over the entire basin rises of about 2 or 7 cm in 50 years depending on the Atlantic boundary conditions. The difference of about 1 C and 0.5 psu in the upper layers of the Atlantic sea reflects mainly on the halosteric component that contributes negatively to the sea level rise, when fresher and colder boundary conditions are used in the Atlantic buffer zone, and positively in the other case. The impact of the boundary conditions is not uniform in the basin and is particularly strong in some easternmost regions. (orig.)

  6. Steric control of the donor/acceptor interface: Implications in organic photovoltaic charge generation

    KAUST Repository

    Holcombe, Thomas W.

    2011-08-10

    The performance of organic photovoltaic (OPV) devices is currently limited by modest short-circuit current densities. Approaches toward improving this output parameter may provide new avenues to advance OPV technologies and the basic science of charge transfer in organic semiconductors. This work highlights how steric control of the charge separation interface can be effectively tuned in OPV devices. By introducing an octylphenyl substituent onto the investigated polymer backbones, the thermally relaxed charge-transfer state, and potentially excited charge-transfer states, can be raised in energy. This decreases the barrier to charge separation and results in increased photocurrent generation. This finding is of particular significance for nonfullerene OPVs, which have many potential advantages such as tunable energy levels and spectral breadth, but are prone to poor exciton separation efficiencies. Computational, spectroscopic, and synthetic methods were combined to develop a structure-property relationship that correlates polymer substituents with charge-transfer state energies and, ultimately, device efficiencies. © 2011 American Chemical Society.

  7. Design, Synthesis, and Biological Features of Platinum(II) Complexes with Rigid Steric Hindrance.

    Science.gov (United States)

    Wang, Zhimei; Yu, Haiyan; Gou, Shaohua; Chen, Feihong; Fang, Lei

    2016-05-01

    A series of platinum(II) complexes, with N-monosubstituted 1R,2R-diaminocyclohexane bearing methoxy-substituted benzyl groups as carrier ligands, were designed and synthesized. The newly prepared compounds, with chloride anions as leaving groups, were found to be very active against the tested cancer cell lines, including a cisplatin-resistant cell line. Despite their efficacy against tumor cells, they also showed low toxicity to a human normal liver cell line. Among them, complex 1 had superior cytotoxic activity against A549, HCT-116, MCF-7, SGC7901, and SGC7901/CDDP cancer cell lines. The DNA binding assay is of further special interest, as an unusual monofunctional binding mode was found, due to the introduction of a rigid substituted aromatic ring in the 1R,2R-diaminocyclohexane framework as steric hindrance. The linkage of complex 1 with DNA was stable and insensitive to nucleophilic attack. Moreover, studies including cellular uptake, gel electrophoresis, apoptosis and cell cycle, and Western blot analysis have provided insight into the high potency of this compound. PMID:27074104

  8. Attractive S⋯π and π-π interactions in the pyrazine-2-thiocarboxamide structure: Experimental and computational studies in the context of crystal engineering and microbiological properties

    Science.gov (United States)

    Chylewska, Agnieszka; Sikorski, Artur; Ogryzek, Małgorzata; Makowski, Mariusz

    2016-02-01

    Pyrazine-2-thiocarboxamide (PTCA) was obtained after recrystallization and was characterised by elemental analysis, IR spectroscopy and thermogravimetry. Five dimers of PTCA were found in X-ray diffraction studies. These results were then compared with the known structures of a popular drug, i.e. pyrazine-2-carboxamide (PZA). S⋯π and π-π interactions were observed in the PTCA crystal structure as a novelty in X-ray measurements and our attention was focused on their role in stabilizing the PCTA structure. The geometry, energy and IR spectra for two conformers (E, Z) of PTCA and five dimers (D1-D5) were calculated for the gas phase with the DFT method at 6-311 + G(d,p) basis set. The results of calculations showed that D1 is the most stable dimer among five dimers of PTCA which were found experimentally. Thermal decomposition of PTCA was examined with the use of the TG/IR analysis (20-1000 °C) and the results were discussed. To test the antimicrobial activity of PTCA a biological assay was performed to determine its potentially pharmaceutical applications. The minimum inhibitory (MIC) and minimal bactericidal (fungicidal) concentrations (MBC) for PTCA were determined against six microorganisms.

  9. Company, its performance and perceived employer attractiveness

    OpenAIRE

    Musilová, Jana

    2014-01-01

    This thesis analyses influencers of employer attractiveness with high focus on company performance and other elements concerning company as such. Theoretical part of this thesis aims to bring relevant background for the practical analysis. In particular, it examines areas such as talent management, employee value proposition and employer branding and their connection to employer attractiveness. Practical part identifies objective and subjective drivers of employer attractiveness. This part co...

  10. Rationalizing polymer swelling and collapse under repulsive to highly attractive cosolvent conditions

    OpenAIRE

    Muzdalo, Anja; Heyda, Jan; Dzubiella, Joachim

    2012-01-01

    The collapse and swelling behavior of a generic homopolymer is studied using implicit-solvent, explicit-cosolvent Langevin dynamics computer simulations for varying interaction strengths. The systematic investigation reveals that polymer swelling is maximal if both monomer-monomer and monomer-cosolute interactions are weakly attractive. In the most swollen state the cosolute density inside the coil is remarkably bulk-like and homogenous. Highly attractive monomer-cosolute interactions, howeve...

  11. A neural link between affective understanding and interpersonal attraction.

    Science.gov (United States)

    Anders, Silke; de Jong, Roos; Beck, Christian; Haynes, John-Dylan; Ethofer, Thomas

    2016-04-19

    Being able to comprehend another person's intentions and emotions is essential for successful social interaction. However, it is currently unknown whether the human brain possesses a neural mechanism that attracts people to others whose mental states they can easily understand. Here we show that the degree to which a person feels attracted to another person can change while they observe the other's affective behavior, and that these changes depend on the observer's confidence in having correctly understood the other's affective state. At the neural level, changes in interpersonal attraction were predicted by activity in the reward system of the observer's brain. Importantly, these effects were specific to individual observer-target pairs and could not be explained by a target's general attractiveness or expressivity. Furthermore, using multivoxel pattern analysis (MVPA), we found that neural activity in the reward system of the observer's brain varied as a function of how well the target's affective behavior matched the observer's neural representation of the underlying affective state: The greater the match, the larger the brain's intrinsic reward signal. Taken together, these findings provide evidence that reward-related neural activity during social encounters signals how well an individual's "neural vocabulary" is suited to infer another person's affective state, and that this intrinsic reward might be a source of changes in interpersonal attraction. PMID:27044071

  12. Bodily attractiveness and egalitarianism are negatively related in males.

    Science.gov (United States)

    Price, Michael E; Brown, Stuart; Dukes, Amber; Kang, Jinsheng

    2015-01-01

    Ancestrally, relatively attractive individuals and relatively formidable males may have had reduced incentives to be egalitarian (i.e., to act in accordance with norms promoting social equality). If selection calibrated one's egalitarianism to one's attractiveness/formidability, then such people may exhibit reduced egalitarianism ("observed egalitarianism") and be perceived by others as less egalitarian ("perceived egalitarianism") in modern environments. To investigate, we created 3D body models of 125 participants to use both as a source of anthropometric measurements and as stimuli to obtain ratings of bodily attractiveness and perceived egalitarianism. We also measured observed egalitarianism (via an economic "dictator" game) and indices of political egalitarianism (preference for socialism over capitalism) and "equity sensitivity." Results indicated higher egalitarianism levels in women than in men, and moderate-to-strong negative relationships between (a) attractiveness and observed egalitarianism among men, (b) attractiveness and perceived egalitarianism among both sexes, and (c) formidability and perceived egalitarianism among men. We did not find support for two previously-reported findings: that observed egalitarianism and formidability are negatively related in men, and that wealth and formidability interact to explain variance in male egalitarianism. However, this lack of support may have been due to differences in variable measurement between our study and previous studies. PMID:25664560

  13. Moving attractive virtual agent improves interpersonal coordination stability.

    Science.gov (United States)

    Zhao, Zhong; Salesse, Robin N; Gueugnon, Mathieu; Schmidt, Richard C; Marin, Ludovic; Bardy, Benoît G

    2015-06-01

    Interpersonal motor coordination is influenced not only by biomechanical factors such as coordination pattern, oscillating frequency, and individual differences, but also by psychosocial factor such as likability and social competences. Based on the social stereotype of "what is beautiful is good", the present study aimed at investigating whether people coordinate differently with physically attractive people compared to less attractive people. 34 participants were engaged in an interpersonal coordination task with different looking (virtual) agents while performing at the same time a reaction time task. Results showed that participants had more stable motor coordination with the moving attractive than with the less attractive agent, and that the difference in motor coordination could not be interpreted by a specific attention allocation strategy. Our findings provide the evidence that physical attractiveness genuinely affects how people interact with another person, and that the temporal-spatial coordinated movement varies with the partner's psychosocial characteristics. The study broadens the perspective of exploring the effect of additional psychosocial factors on social motor coordination. PMID:25854798

  14. Attractiveness and activity in Internet communities

    CERN Document Server

    Ghoshal, G; Ghoshal, Gourab; Holme, Petter

    2005-01-01

    Datasets of online communication often take the form of contact sequences -- ordered lists contacts (where a contact is defined as a triple of a sender, a recipient and a time). We propose measures of attractiveness and activity for such data sets and analyze these quantities for anonymized contact sequences from an Internet dating community. For this data set the attractiveness and activity measures show broad power-law like distributions. Our attractiveness and activity measures are more strongly correlated in the real-world data than in our reference model. Effects that indirectly can make active users more attractive are discussed.

  15. Meeting your match: how attractiveness similarity affects approach behavior in mixed-sex dyads.

    Science.gov (United States)

    van Straaten, Ischa; Engels, Rutger C M E; Finkenauer, Catrin; Holland, Rob W

    2009-06-01

    This experimental study investigated approach behavior toward opposite-sex others of similar versus dissimilar physical attractiveness. Furthermore, it tested the moderating effects of sex. Single participants interacted with confederates of high and low attractiveness. Observers rated their behavior in terms of relational investment (i.e., behavioral efforts related to the improvement of interaction fluency, communication of positive interpersonal affect, and positive self-presentation). As expected, men displayed more relational investment behavior if their own physical attractiveness was similar to that of the confederate. For women, no effects of attractiveness similarity on relational investment behavior were found. Results are discussed in the light of positive assortative mating, preferences for physically attractive mates, and sex differences in attraction-related interpersonal behaviors. PMID:19336540

  16. Drought and leaf herbivory influence floral volatiles and pollinator attraction.

    Science.gov (United States)

    Burkle, Laura A; Runyon, Justin B

    2016-04-01

    The effects of climate change on species interactions are poorly understood. Investigating the mechanisms by which species interactions may shift under altered environmental conditions will help form a more predictive understanding of such shifts. In particular, components of climate change have the potential to strongly influence floral volatile organic compounds (VOCs) and, in turn, plant-pollinator interactions. In this study, we experimentally manipulated drought and herbivory for four forb species to determine effects of these treatments and their interactions on (1) visual plant traits traditionally associated with pollinator attraction, (2) floral VOCs, and (3) the visitation rates and community composition of pollinators. For all forbs tested, experimental drought universally reduced flower size and floral display, but there were species-specific effects of drought on volatile emissions per flower, the composition of compounds produced, and subsequent pollinator visitation rates. Moreover, the community of pollinating visitors was influenced by drought across forb species (i.e. some pollinator species were deterred by drought while others were attracted). Together, these results indicate that VOCs may provide more nuanced information to potential floral visitors and may be relatively more important than visual traits for pollinator attraction, particularly under shifting environmental conditions. PMID:26546275

  17. Attracted to power: challenge/threat and promotion/prevention focus differentially predict the attractiveness of group power.

    Science.gov (United States)

    Scholl, Annika; Sassenrath, Claudia; Sassenberg, Kai

    2015-01-01

    Depending on their motivation, individuals prefer different group contexts for social interactions. The present research sought to provide more insight into this relationship. More specifically, we tested how challenge/threat and a promotion/prevention focus predict attraction to groups with high- or low-power. As such, we examined differential outcomes of threat and prevention focus as well as challenge and promotion focus that have often been regarded as closely related. According to regulatory focus, individuals should prefer groups that they expect to "feel right" for them to join: Low-power groups should be more attractive in a prevention (than a promotion) focus, as these groups suggest security-oriented strategies, which fit a prevention focus. High-power groups should be more attractive in a promotion (rather than a prevention) focus, as these groups are associated with promotion strategies fitting a promotion focus (Sassenberg et al., 2007). In contrast, under threat (vs. challenge), groups that allow individuals to restore their (perceived) lack of control should be preferred: Low-power groups should be less attractive under threat (than challenge) because they provide low resources which threatened individuals already perceive as insufficient and high-power groups might be more attractive under threat (than under challenge), because their high resources allow individuals to restore control. Two experiments (N = 140) supported these predictions. The attractiveness of a group often depends on the motivation to engage in what fits (i.e., prefer a group that feels right in the light of one's regulatory focus). However, under threat the striving to restore control (i.e., prefer a group allowing them to change the status quo under threat vs. challenge) overrides the fit effect, which may in turn guide individuals' behavior in social interactions. PMID:25904887

  18. Correlation of the solubility of several aromatics and terpenes in aqueous hydroxypropyl-beta-cyclodextrin with steric and hydrophobicity parameters.

    Science.gov (United States)

    Demian, B A

    2000-10-01

    The solubility isotherms of nineteen aromatics and terpenes in aqueous hydroxypropyl-beta-cyclodextrin were determined to be straight lines. This is explained by the host-guest complexation which is characteristic for the whole class of cyclodextrins and derivatives. The slopes of the solubility isotherms correlate with Sterimol L and log P(ow) as descriptors of the steric fit and hydrophobicity match, in accord with the qualitative representation of the phenomenon. PMID:11093722

  19. An efficient way to coupling amine with derivatives of steric N-Boc-pyrrolidine-2-carboxylic acid

    Institute of Scientific and Technical Information of China (English)

    Feng Zhi Liu; Hao Fang; Wen Fang Xu

    2007-01-01

    An efficient way to coupling amine with the derivatives of steric N-Boc-pyrrolidine-2-carboxylic acid was reported in this paper.We have found that the synthesis of derivatives is problematic with the commonly used DCC/HOBT method. As a substitute, the mixed anhydride method was adopted. A series of 6-(3-nitroguanidino)hexanamidopyrrolidine derivatives were prepared with this method.

  20. Studies on the synthesis of (-)-spinosyn a: application of the steric directing group strategy to transannular Diels-Alder reactions.

    Science.gov (United States)

    Frank, Scott A; Roush, William R

    2002-06-14

    A highly diastereoselective and enantioselective synthesis of the decahydro-as-indacene nucleus 12 of (-)-spinosyn A (1) is reported. By implementing the steric directing group strategy, tricyclic lactone 37 was produced from a remarkably diastereoselective transannular Diels-Alder reaction of lactone 9. The tricyclic core of the natural product was then obtained by using an Ireland-Claisen ring contraction of 37. Reversal of the order of these two steps resulted in an almost complete loss of diastereoselectivity. PMID:12054969

  1. How nonlinearities in the equation of state of seawater can confound estimates of steric sea level change

    OpenAIRE

    Gille, Sarah T.

    2004-01-01

    The process of mixing water masses that have differing temperatures, salinities, and pressures creates water that is typically denser than the average density of the source waters. Thus mixing the ocean, either along isopycnals or vertically, tends to decrease global sea level, even when no heat or salt is added to the ocean. This effect is small in the global ocean, but regional effects can be substantial. Two recommendations emerge from this study. First, numerical predictions of steric ...

  2. Design of perylene diimides for organic solar cell: Effect of molecular steric hindrance and extended conjugation

    Energy Technology Data Exchange (ETDEWEB)

    Kozma, Erika, E-mail: erika.kozma@ismac.cnr.it [Istituto per lo Studio delle Macromolecole, Consiglio Nazionale delle Ricerche, 20133 Milano (Italy); Kotowski, Dariusz; Catellani, Marinella; Luzzati, Silvia [Istituto per lo Studio delle Macromolecole, Consiglio Nazionale delle Ricerche, 20133 Milano (Italy); Cavazzini, Marco; Bossi, Alberto; Orlandi, Simonetta [Istituto di Scienze e Tecnologie Molecolari, Consiglio Nazionale delle Ricerche, 20133 Milano (Italy); Bertini, Fabio [Istituto per lo Studio delle Macromolecole, Consiglio Nazionale delle Ricerche, 20133 Milano (Italy)

    2015-08-01

    Core-substituted perylene diimides (PDI) are promising candidates as n-type semiconductor materials for organic photovoltaics. The chemical functionalization of perylene diimides in the bay positions is a versatile tool to obtain a series of electron acceptor materials with tunable electron affinity. These materials usually feature a donor-acceptor D-A structure in which the electron withdrawing PDI core is covalently linked with different electron donating chemical groups. The structural and electronic properties of the substituents define and modulate the optical/electrical properties of the semiconductor and the performance as photovoltaic material. In this work we designed two PDI molecules with D-A-D structure using spirobifluorene group as substituent directly linked to the perylene core (PDI-SF) and with insertion of a bithiophene moiety (PDI-BSF). In both molecules we found a reduced tendency to form aggregates in the solid state thanks to the cross-shaped rigid structure and strong steric hindrance of the spirobifluorene group. Additionally, in the case of PDI-BSF the presence of the bithiophene linker contributes significantly to extend the conjugation, resulting in a panchromatic absorption in the whole visible to NIR region. We present the synthesis of these materials and their characterisation in terms of absorption spectroscopy, cyclic voltammetry and computational calculations. Finally we show preliminary results of their use as active components in P3HT/PDIs bulk heterojunction solar cells. - Highlights: • New D-A-D n-type materials have been synthesized. • PDI-SF and PDI-BSF were used as acceptors in organic solar cells. • Performances of 1.32% were achieved in blend with P3HT in a BHJ conventional architecture.

  3. Nano-Drugs Based on Nano Sterically Stabilized Liposomes for the Treatment of Inflammatory Neurodegenerative Diseases.

    Science.gov (United States)

    Turjeman, Keren; Bavli, Yaelle; Kizelsztein, Pablo; Schilt, Yaelle; Allon, Nahum; Katzir, Tamar Blumenfeld; Sasson, Efrat; Raviv, Uri; Ovadia, Haim; Barenholz, Yechezkel

    2015-01-01

    The present study shows the advantages of liposome-based nano-drugs as a novel strategy of delivering active pharmaceutical ingredients for treatment of neurodegenerative diseases that involve neuroinflammation. We used the most common animal model for multiple sclerosis (MS), mice experimental autoimmune encephalomyelitis (EAE). The main challenges to overcome are the drugs' unfavorable pharmacokinetics and biodistribution, which result in inadequate therapeutic efficacy and in drug toxicity (due to high and repeated dosage). We designed two different liposomal nano-drugs, i.e., nano sterically stabilized liposomes (NSSL), remote loaded with: (a) a "water-soluble" amphipathic weak acid glucocorticosteroid prodrug, methylprednisolone hemisuccinate (MPS) or (b) the amphipathic weak base nitroxide, Tempamine (TMN). For the NSSL-MPS we also compared the effect of passive targeting alone and of active targeting based on short peptide fragments of ApoE or of β-amyloid. Our results clearly show that for NSSL-MPS, active targeting is not superior to passive targeting. For the NSSL-MPS and the NSSL-TMN it was demonstrated that these nano-drugs ameliorate the clinical signs and the pathology of EAE. We have further investigated the MPS nano-drug's therapeutic efficacy and its mechanism of action in both the acute and the adoptive transfer EAE models, as well as optimizing the perfomance of the TMN nano-drug. The highly efficacious anti-inflammatory therapeutic feature of these two nano-drugs meets the criteria of disease-modifying drugs and supports further development and evaluation of these nano-drugs as potential therapeutic agents for diseases with an inflammatory component. PMID:26147975

  4. Design of perylene diimides for organic solar cell: Effect of molecular steric hindrance and extended conjugation

    International Nuclear Information System (INIS)

    Core-substituted perylene diimides (PDI) are promising candidates as n-type semiconductor materials for organic photovoltaics. The chemical functionalization of perylene diimides in the bay positions is a versatile tool to obtain a series of electron acceptor materials with tunable electron affinity. These materials usually feature a donor-acceptor D-A structure in which the electron withdrawing PDI core is covalently linked with different electron donating chemical groups. The structural and electronic properties of the substituents define and modulate the optical/electrical properties of the semiconductor and the performance as photovoltaic material. In this work we designed two PDI molecules with D-A-D structure using spirobifluorene group as substituent directly linked to the perylene core (PDI-SF) and with insertion of a bithiophene moiety (PDI-BSF). In both molecules we found a reduced tendency to form aggregates in the solid state thanks to the cross-shaped rigid structure and strong steric hindrance of the spirobifluorene group. Additionally, in the case of PDI-BSF the presence of the bithiophene linker contributes significantly to extend the conjugation, resulting in a panchromatic absorption in the whole visible to NIR region. We present the synthesis of these materials and their characterisation in terms of absorption spectroscopy, cyclic voltammetry and computational calculations. Finally we show preliminary results of their use as active components in P3HT/PDIs bulk heterojunction solar cells. - Highlights: • New D-A-D n-type materials have been synthesized. • PDI-SF and PDI-BSF were used as acceptors in organic solar cells. • Performances of 1.32% were achieved in blend with P3HT in a BHJ conventional architecture

  5. Nano-Drugs Based on Nano Sterically Stabilized Liposomes for the Treatment of Inflammatory Neurodegenerative Diseases.

    Directory of Open Access Journals (Sweden)

    Keren Turjeman

    Full Text Available The present study shows the advantages of liposome-based nano-drugs as a novel strategy of delivering active pharmaceutical ingredients for treatment of neurodegenerative diseases that involve neuroinflammation. We used the most common animal model for multiple sclerosis (MS, mice experimental autoimmune encephalomyelitis (EAE. The main challenges to overcome are the drugs' unfavorable pharmacokinetics and biodistribution, which result in inadequate therapeutic efficacy and in drug toxicity (due to high and repeated dosage. We designed two different liposomal nano-drugs, i.e., nano sterically stabilized liposomes (NSSL, remote loaded with: (a a "water-soluble" amphipathic weak acid glucocorticosteroid prodrug, methylprednisolone hemisuccinate (MPS or (b the amphipathic weak base nitroxide, Tempamine (TMN. For the NSSL-MPS we also compared the effect of passive targeting alone and of active targeting based on short peptide fragments of ApoE or of β-amyloid. Our results clearly show that for NSSL-MPS, active targeting is not superior to passive targeting. For the NSSL-MPS and the NSSL-TMN it was demonstrated that these nano-drugs ameliorate the clinical signs and the pathology of EAE. We have further investigated the MPS nano-drug's therapeutic efficacy and its mechanism of action in both the acute and the adoptive transfer EAE models, as well as optimizing the perfomance of the TMN nano-drug. The highly efficacious anti-inflammatory therapeutic feature of these two nano-drugs meets the criteria of disease-modifying drugs and supports further development and evaluation of these nano-drugs as potential therapeutic agents for diseases with an inflammatory component.

  6. Solubilization of beclomethasone dipropionate in sterically stabilized phospholipid nanomicelles (SSMs: physicochemical and in vitro evaluations

    Directory of Open Access Journals (Sweden)

    Peh KK

    2012-02-01

    Full Text Available Mohanad Naji Sahib, Shaymaa Abdalwahed Abdulameer, Yusrida Darwis, Kok Khiang Peh, Yvonne Tze Fung TanSchool of Pharmaceutical Sciences, Universiti Sains Malaysia, Penang, MalaysiaBackground: The local treatment of lung disorders such as asthma and chronic obstructive pulmonary disease via pulmonary drug delivery offers many advantages over oral or intravenous routes of administration. This is because direct deposition of a drug at the diseased site increases local drug concentrations, which improves the pulmonary receptor occupancy and reduces the overall dose required, therefore reducing the side effects that result from high drug doses. From a clinical point of view, although jet nebulizers have been used for aerosol delivery of water-soluble compounds and micronized suspensions, their use with hydrophobic drugs has been inadequate.Aim: To evaluate the feasibility of sterically stabilized phospholipid nanomicelles (SSMs loaded with beclomethasone dipropionate (BDP as a carrier for pulmonary delivery.Methods: 1,2-Distearoyl-sn-glycero-3-phosphoethanolamine-N-methoxy-poly(ethylene glycol 5000 polymeric micelles containing BDP (BDP-SSMs were prepared by the coprecipitation and reconstitution method, and the physicochemical and in vitro characteristics of BDP-SSMs were investigated.Results: BDP-SSMs were successfully prepared with a content uniformity and reproducibility suitable for pulmonary administration. The maximum solubility of BDP in SSMs was approximately 1300 times its actual solubility. The particle size and zeta potential of BDP-SSMs were 19.89 ± 0.67 nm and -28.03 ± 2.05 mV, respectively. The SSMs system slowed down the release of BDP and all of the aerodynamic values of the aerosolized rehydrated BDP-SSMs were not only acceptable but indicated a significant level of deposition in the lungs.Conclusion: The SSM system might be an effective way of improving the therapeutic index of nebulized, poorly soluble corticosteroids

  7. Steric effects in release of amides from linkers in solid-phase synthesis. Molecular mechanics modeling of key step in peptide and combinatorial chemistry

    DEFF Research Database (Denmark)

    Norrby, Per-Ola; Jensen, Knud Jørgen

    2006-01-01

    Acidolytic release of an amide from a solid support by C-N bond cleavage is all ubiquitous and crucial step in many solid-phase syntheses. We have used molecular modeling of a pseudo-equilibrium to explore substituent and steric effects in the release of peptides. The high acid-lability of the...... the lability of a linkage. In addition, predictions indicated that steric effects from the C-alpha-substituent in a BAL anchored amino acid residue should accelerate the acidolytic release. The finding that steric crowding leads to increased acid-lability will be important for further development and...

  8. Steric hindrance regulated supramolecular assembly between β-cyclodextrin polymer and pyrene for alkaline phosphatase fluorescent sensing

    Science.gov (United States)

    Song, Chunxia; Yang, Xiaohai; Wang, Kemin; Wang, Qing; Liu, Jianbo; Huang, Jin; Zhou, Maogui; Guo, Xiaochen

    2016-03-01

    We herein report a strategy for sensitive alkaline phosphatase (ALP) fluorescent sensing based on steric hindrance regulated supramolecular assembly between β-cyclodextrin polymer (polyβ-CD) and pyrene. The fluorescence of pyrene was enhanced more than 10 times through supramolecular assembly with polyβ-CD. The 5‧-phosphorylated dsDNA probe with pyrene attached on the 3‧-terminal could be cleaved by λ exonuclease (λ exo), yielding pyrene attached on mononucleotides. Pyrene attached on mononucleotides could easily enter the cavity of polyβ-CD, resulting in fluorescence enhancement. When ALP was introduced, it could remove 5‧-phosphate groups from dsDNA and then prevented the cleavage of dsDNA. Pyrene attached on dsDNA was difficult to enter the cavity of polyβ-CD because of steric hindrance, resulting in an inconspicuous fluorescence enhancement. Owing to the excellent fluorescence enhancement during steric hindrance regulated supramolecular assembly, excellent performance of the assay method was achieved for ALP with a detection limit of 0.04 U mL- 1. The detection limit was superior or comparable with the reported methods. Besides, this method was simple in design, avoiding double-labeling of probe.

  9. The influence of facial attractiveness on imitation

    NARCIS (Netherlands)

    Leeuwen, M.L. van; Veling, H.P.; Baaren, R.B. van; Dijksterhuis, A.J.

    2009-01-01

    People judge, evaluate, and treat attractive people better than moderately attractive or unattractive people [Langlois, J. H., Kalakanis, L., Rubenstein, A. J., Larson, A., Hallam, M., & Smoot, M. (2000). Maxims or myths of beauty? A meta-analytic and theoretical review. Psychological Bulletin, 126,

  10. Correlates of Attraction Among Preschool Children.

    Science.gov (United States)

    Ross, Michael B.

    The generalizability of several variables which have been related to attraction among adults to preschool children was investigated. It was found that perceived physical attractiveness, perceived proximity, and familiarity are all significantly positively correlated with how popular a child is in his nursery school class. (Author)

  11. An Attributional Approach to Counselor Attractiveness.

    Science.gov (United States)

    Hackman, Hollis W.; Claiborn, Charles D.

    1982-01-01

    Examined two components of counselor attractiveness--perceived similarity and liking--in a comparison of two theoretical approaches to attractiveness and influence in counseling--the referent power hypothesis and an attributional approach. Results generally support the attributional approach over the reference power hypothesis. (Author)

  12. Brain Systems for Assessing Facial Attractiveness

    Science.gov (United States)

    Winston, Joel S.; O'Doherty, John; Kilner, James M.; Perrett, David I.; Dolan, Raymond J.

    2007-01-01

    Attractiveness is a facial attribute that shapes human affiliative behaviours. In a previous study we reported a linear response to facial attractiveness in orbitofrontal cortex (OFC), a region involved in reward processing. There are strong theoretical grounds for the hypothesis that coding stimulus reward value also involves the amygdala. The…

  13. Reciprocity of Interpersonal Attraction: A Confirmed Hypothesis.

    Science.gov (United States)

    La Voie, Lawrence; Kenny, David A.

    An increase in reciprocity of interpersonal attraction during the early acquaintance period followed by continuing social reciprocity are propositions that are central principles of several social psychological viewpoints. However, there is little empirical evidence of increasing reciprocity of interpersonal attraction over time. Two potential…

  14. Attraction, Discrepancy and Responses to Psychological Treatment.

    Science.gov (United States)

    Patton, Michael J.

    The responses of a laboratory subject (S) to a counselor-accomplice and to the psychological treatment situation are examined by manipulating experimentally interpersonal attraction and communication discrepancy. Four treatment conditions were set up: (1) topic similarity and positive attraction for counselor, (2) topic discrepancy and positive…

  15. Branner-Hubbard motions and attracting dynamics

    DEFF Research Database (Denmark)

    Petersen, Carsten Lunde; Tan, Lei

    We introduce the new notion an aatracting dynamics, which is related to polynomial-likke mappings. Also we review the Branner-Hubbard motion and study its action on attracting dynamics.......We introduce the new notion an aatracting dynamics, which is related to polynomial-likke mappings. Also we review the Branner-Hubbard motion and study its action on attracting dynamics....

  16. Electron attraction mediated by Coulomb repulsion

    Science.gov (United States)

    Hamo, A.; Benyamini, A.; Shapir, I.; Khivrich, I.; Waissman, J.; Kaasbjerg, K.; Oreg, Y.; von Oppen, F.; Ilani, S.

    2016-07-01

    One of the defining properties of electrons is their mutual Coulomb repulsion. However, in solids this basic property may change; for example, in superconductors, the coupling of electrons to lattice vibrations makes the electrons attract one another, leading to the formation of bound pairs. Fifty years ago it was proposed that electrons can be made attractive even when all of the degrees of freedom in the solid are electronic, by exploiting their repulsion from other electrons. This attraction mechanism, termed ‘excitonic’, promised to achieve stronger and more exotic superconductivity. Yet, despite an extensive search, experimental evidence for excitonic attraction has yet to be found. Here we demonstrate this attraction by constructing, from the bottom up, the fundamental building block of the excitonic mechanism. Our experiments are based on quantum devices made from pristine carbon nanotubes, combined with cryogenic precision manipulation. Using this platform, we demonstrate that two electrons can be made to attract each other using an independent electronic system as the ‘glue’ that mediates attraction. Owing to its tunability, our system offers insights into the underlying physics, such as the dependence of the emergent attraction on the underlying repulsion, and the origin of the pairing energy. We also demonstrate transport signatures of excitonic pairing. This experimental demonstration of excitonic pairing paves the way for the design of exotic states of matter.

  17. Positive illusions about one's partner's physical attractiveness

    NARCIS (Netherlands)

    Barelds-Dijkstra, Pieternel; Barelds, Dick P. H.

    2008-01-01

    This study examined couples' ratings of self and partner physical attractiveness. On the basis of the theory of positive illusions, it was expected that individuals would rate their partners as more attractive than their partners would rate themselves. Both members of 93 heterosexual couples, with a

  18. Interpersonal Attraction in the Counseling Relationship.

    Science.gov (United States)

    Wachowiak, Dale; Diaz, Sandra

    Murstein's Stimulus-Value-Role theory of dyadic relationships, in which attraction depends on the exchange value of the assets and liabilities each person brings to the situation, is employed as a foundation for this review of the literature on interpersonal attraction in the counseling relationship. A three-stage model, accounting for both…

  19. How facial attractiveness affects sustained attention.

    Science.gov (United States)

    Li, Jie; Oksama, Lauri; Hyönä, Jukka

    2016-10-01

    The present study investigated whether and how facial attractiveness affects sustained attention. We adopted a multiple-identity tracking paradigm, using attractive and unattractive faces as stimuli. Participants were required to track moving target faces amid distractor faces and report the final location of each target. In Experiment 1, the attractive and unattractive faces differed in both the low-level properties (i.e., luminance, contrast, and color saturation) and high-level properties (i.e., physical beauty and age). The results showed that the attractiveness of both the target and distractor faces affected the tracking performance: The attractive target faces were tracked better than the unattractive target faces; when the targets and distractors were both unattractive male faces, the tracking performance was poorer than when they were of different attractiveness. In Experiment 2, the low-level properties of the facial images were equalized. The results showed that the attractive target faces were still tracked better than unattractive targets while the effects related to distractor attractiveness ceased to exist. Taken together, the results indicate that during attentional tracking the high-level properties related to the attractiveness of the target faces can be automatically processed, and then they can facilitate the sustained attention on the attractive targets, either with or without the supplement of low-level properties. On the other hand, only low-level properties of the distractor faces can be processed. When the distractors share similar low-level properties with the targets, they can be grouped together, so that it would be more difficult to sustain attention on the individual targets. PMID:27347672

  20. Iterated perturbation theory for the attractive Holstein and Hubbard models

    OpenAIRE

    Freericks, J. K.; Jarrell, Mark (Eds. )

    1994-01-01

    A strictly truncated (weak-coupling) perturbation theory is applied to the attractive Holstein and Hubbard models in infinite dimensions. These results are qualified by comparison with essentially exact Monte Carlo results. The second order iterated perturbation theory is shown to be quite accurate in calculating transition temperatures for retarded interactions, but is not as accurate for the self energy or the irreducible vertex functions themselves. Iterated perturbation theory is carried ...

  1. Opposites attract: a theorem about the Casimir Force.

    Science.gov (United States)

    Kenneth, Oded; Klich, Israel

    2006-10-20

    We consider the Casimir interaction between (nonmagnetic) dielectric bodies or conductors. Our main result is a proof that the Casimir force between two bodies related by reflection is always attractive, independent of the exact form of the bodies or dielectric properties. Apart from being a fundamental property of fields, the theorem and its corollaries also rule out a class of suggestions to obtain repulsive forces, such as the two hemisphere repulsion suggestion and its relatives. PMID:17155375

  2. Opposites Attract: A Theorem about the Casimir Force

    OpenAIRE

    Kenneth, Oded; Klich, Israel

    2006-01-01

    We consider the Casimir interaction between (non-magnetic) dielectric bodies or conductors. Our main result is a proof that the Casimir force between two bodies related by reflection is always attractive, independent of the exact form of the bodies or dielectric properties. Apart from being a fundamental property of fields, the theorem and its corollaries also rule out a class of suggestions to obtain repulsive forces, such as the two hemisphere repulsion suggestion and its relatives.

  3. Liquid drops attract or repel by the inverted Cheerios effect.

    Science.gov (United States)

    Karpitschka, Stefan; Pandey, Anupam; Lubbers, Luuk A; Weijs, Joost H; Botto, Lorenzo; Das, Siddhartha; Andreotti, Bruno; Snoeijer, Jacco H

    2016-07-01

    Solid particles floating at a liquid interface exhibit a long-ranged attraction mediated by surface tension. In the absence of bulk elasticity, this is the dominant lateral interaction of mechanical origin. Here, we show that an analogous long-range interaction occurs between adjacent droplets on solid substrates, which crucially relies on a combination of capillarity and bulk elasticity. We experimentally observe the interaction between droplets on soft gels and provide a theoretical framework that quantitatively predicts the interaction force between the droplets. Remarkably, we find that, although on thick substrates the interaction is purely attractive and leads to drop-drop coalescence, for relatively thin substrates a short-range repulsion occurs, which prevents the two drops from coming into direct contact. This versatile interaction is the liquid-on-solid analog of the "Cheerios effect." The effect will strongly influence the condensation and coarsening of drops on soft polymer films, and has potential implications for colloidal assembly and mechanobiology. PMID:27298348

  4. Physical Attractiveness and Public Intimacy of Married Couples: An Observational Study.

    Science.gov (United States)

    Harrell, W. Andrew

    1979-01-01

    Findings indicated that physically attractive couples were more likely to show public intimacy. Younger couples displayed more intimacy than older couples. Couples who were similar in age interacted more than couples who differed in age. Husband-wife attractiveness did not significantly influence intimacy. (Author/BEF)

  5. Organizational Forms Of Banks Participation In Ensuring Of Investment Attractiveness Of The Regions

    OpenAIRE

    Yuriy Vasylyshen

    2014-01-01

    In the article it is grounded the forms of banks participation in ensuring of investment attractiveness of the regions. In particular, the peculiarities of banks interaction with the state and business as well as the foundations of their effective cooperation are defined. The main activity types of banking institutions in ensuring of investment attractiveness of a region are determined.

  6. INTERACT

    DEFF Research Database (Denmark)

    Jochum, Elizabeth; Borggreen, Gunhild; Murphey, TD

    , and demonstrated in public settings. We then describe INTERACT, a proposed research project that stages the robotic marionettes in a live performance. The interdisciplinary project brings humanities research to bear on scientific and technological inquiry, and culminates in the development a live......This paper considers the impact of visual art and performance on robotics and human-computer interaction and outlines a research project that combines puppetry and live performance with robotics. Kinesics—communication through movement—is the foundation of many theatre and performance traditions...... interaction between a human operator and an artificial actor or agent. We can apply insights from puppetry to develop culturally-aware robots. Here we describe the development of a robotic marionette theatre wherein robotic controllers assume the role of human puppeteers. The system has been built, tested...

  7. Determination of Effective Particle Density for Sterically Stabilized Carbon Black Particles: Effect of Diblock Copolymer Stabilizer Composition.

    Science.gov (United States)

    Growney, David J; Fowler, Patrick W; Mykhaylyk, Oleksandr O; Fielding, Lee A; Derry, Matthew J; Aragrag, Najib; Lamb, Gordon D; Armes, Steven P

    2015-08-18

    Two poly(styrene-b-hydrogenated isoprene) (PS-PEP) copolymers and a poly(styrene-b-hydrogenated butadiene) (PS-PB) diblock copolymer of differing polystyrene content (20, 28 or 35 mol %) and molecular weight (117-183 kg mol(-1)) are examined. These copolymers form star-like micelles in n-dodecane, as judged by TEM, DLS, and SAXS studies. At ambient temperature, such micelles are known to adsorb intact onto a model colloidal substrate such as carbon black, conferring a high degree of dispersion (Growney, D. J.; Mykhaylyk, O. O.; Armes, S. P. Langmuir 2014, 30, 6047). Isotherms for micellar adsorption on carbon black at 20 °C are constructed using a supernatant depletion assay based on UV spectroscopy by utilizing the aromatic chromophore in the polystyrene block. Perhaps surprisingly, the diblock copolymer with the lowest polystyrene content has the strongest affinity for the carbon black particles. Assuming that the star-like diblock copolymer micelles adsorb onto carbon black to form hemi-micelles with a stabilizer layer thickness equal to the mean micelle radius, the effective particle density of the resulting sterically stabilized carbon black particles in n-dodecane can be estimated from the SAXS micelle dimensions based on geometric considerations. As an approximation, a spherical core-shell morphology was assumed, and the primary grain size of the carbon black particles was determined to be 74 nm diameter as judged by BET surface area analysis. Using this approach, effective particle densities of 0.90, 0.91, and 0.92 g cm(-3) were calculated for sterically stabilized carbon black particles prepared using the PS-PB20, PS-PEP28, and PS-PEP35 diblock copolymers, respectively. These densities are significantly lower than that of carbon black (1.89 g cm(-3)), which indicates that the sterically stabilized carbon black particles are substantially solvated. Since the rate of sedimentation of the sterically stabilized carbon black particles depends on the density

  8. Attractive forces study in macromolecules and critical systems

    International Nuclear Information System (INIS)

    The attractive forces effect is particularly interesting at the proximity of a critical point. In a liquid system, there are two kinds of attractive forces in presence : the forces bound to the solution volume and those generated by the presence of the solution surface or by a solution interface. In the first case, the attractive forces are the more important as the system is in a critical field. For this study, the selected example is a polymer solution in a two solvents mixture. A formulation in terms of way integrals as part of statistical physics has lead us to find again some known results on the polymer chain conformation in the presence of two solvents (collapse of the polymer on itself) far from the critical point and to extend these results to the critical field. In the case of attractive forces created by the surface in some critical systems (polymer of infinite size in solution and binary mixture near the de mixture point), the adsorption profile created by the attraction of one specie by the surface, follows a scale law. The optical methods usually used for the study of these systems do not give characteristic sign of concentration profile in power law. In the case where the interaction potential between radiation and matter is attractive, the reflectivity gives a separate mark of the existence of the scale law in the form of a resonance. After some theoretical forecasts, the author has used this method on the binary mixture methanol-cyclohexane in order to reveal experimentally a reflectivity pseudo-discontinuity and then the existence of the power law in the critical adsorption profile. (O.L.). 69 refs., 60 tabs

  9. Bodily Attraction: How Self-Perceived Attractiveness May Influence Judgement of Potential Partners

    OpenAIRE

    Chung, Kirsten

    2012-01-01

    The evolutionary theory has suggested that there are specific bodily traits that humans find attractive when looking for a potential partner. If the aspiration levels of attractiveness were based on personality measures such as self-perceived attractiveness, self-esteem, narcissism and self-perceived mating success then those who score highly in these measures would have higher aspirational levels and rate bodies with sexually dimorphic traits as more attractive. This study aimed to look at t...

  10. Interactions

    DEFF Research Database (Denmark)

    The main theme of this anthology is the unique interaction between mathematics, physics and philosophy during the beginning of the 20th century. Seminal theories of modern physics and new fundamental mathematical structures were discovered or formed in this period. Significant physicists such as...

  11. Beautiful is Good: Evidence That the Physically Attractive Are More Socially Skillful

    Science.gov (United States)

    Goldman, William; Lewis, Philip

    1977-01-01

    The possibility that the so-called physical attractiveness stereotype may contain a "kernel of truth" was investigated in a study where college students interacted with opposite sex partners whom they could not see. (Editor)

  12. Interplay of alternative conjugated pathways and steric interactions on the electronic and optical properties of donor-acceptor conjugated polymers

    KAUST Repository

    Lima, Igo T.

    2014-01-01

    Donor-acceptor π-conjugated copolymers are of interest for a wide range of electronic applications, including field-effect transistors and solar cells. Here, we present a density functional theory (DFT) study of the impact of varying the conjugation pathway on the geometric, electronic, and optical properties of donor-acceptor systems. We consider both linear ("in series"), traditional conjugation among the donor-acceptor moieties versus structures where the acceptor units are appended orthogonally to the linear, donor-only conjugated backbone. Long-range-corrected hybrid functionals are used in the investigation with the values of the tuned long-range separation parameters providing an estimate of the extent of conjugation as a function of the oligomer architecture. Considerable differences in the electronic and optical properties are determined as a function of the nature of the conjugation pathway, features that should be taken into account in the design of donor-acceptor copolymers.

  13. Are Happy Faces Attractive? The Roles of Early vs. Late Processing.

    Science.gov (United States)

    Sun, Delin; Chan, Chetwyn C H; Fan, Jintu; Wu, Yi; Lee, Tatia M C

    2015-01-01

    Facial attractiveness is closely related to romantic love. To understand if the neural underpinnings of perceived facial attractiveness and facial expression are similar constructs, we recorded neural signals using an event-related potential (ERP) methodology for 20 participants who were viewing faces with varied attractiveness and expressions. We found that attractiveness and expression were reflected by two early components, P2-lateral (P2l) and P2-medial (P2m), respectively; their interaction effect was reflected by LPP, a late component. The findings suggested that facial attractiveness and expression are first processed in parallel for discrimination between stimuli. After the initial processing, more attentional resources are allocated to the faces with the most positive or most negative valence in both the attractiveness and expression dimensions. The findings contribute to the theoretical model of face perception. PMID:26648885

  14. Are Happy Faces Attractive? The Roles of Early versus Late Processing

    Directory of Open Access Journals (Sweden)

    Delin eSun

    2015-11-01

    Full Text Available Facial attractiveness is closely related to romantic love. To understand if the neural underpinnings of perceived facial attractiveness and facial expression are similar constructs, we recorded neural signals using an event-related potential (ERP methodology for 20 participants who were viewing faces with varied attractiveness and expressions. We found that attractiveness and expression were reflected by two early components, P2-lateral (P2l and P2-medial (P2m, respectively; their interaction effect was reflected by LPP, a late component. The findings suggested that facial attractiveness and expression are first processed in parallel for discrimination between stimuli. After the initial processing, more attentional resources are allocated to the faces with the most positive or most negative valence in both the attractiveness and expression dimensions. The findings contribute to the theoretical model of face perception.

  15. In the Eye of the Betrothed: Perceptual Downgrading of Attractive Alternative Romantic Partners.

    Science.gov (United States)

    Cole, Shana; Trope, Yaacov; Balcetis, Emily

    2016-07-01

    People in monogamous relationships can experience a conflict when they interact with an attractive individual. They may have a desire to romantically pursue the new person, while wanting to be faithful to their partner. How do people manage the threat that attractive alternatives present to their relationship goals? We suggest that one way people defend their relationships against attractive individuals is by perceiving the individual as less attractive. In two studies, using a novel visual matching paradigm, we found support for a perceptual downgrading effect. People in relationships perceived threatening attractive individuals as less attractive than did single participants. The effect was exacerbated among participants who were highly satisfied with their current relationships. The studies provide evidence for a perceptual bias that emerges to protect long-term goals. We discuss the findings within the context of a broader theory of motivated perception in the service of self-control. PMID:27207780

  16. Quantitative Methods to Evaluate Timetable Attractiveness

    DEFF Research Database (Denmark)

    Schittenhelm, Bernd; Landex, Alex

    2009-01-01

    timetable is, the article categorizes the different interests for each key stakeholder. Based on this categorization, the most important timetable attractiveness parameters are described (timetable structure, timetable complexity, travel time, transfers, punctuality and reliability). The descriptions...

  17. Integrating body movement into attractiveness research.

    Science.gov (United States)

    Fink, Bernhard; Weege, Bettina; Neave, Nick; Pham, Michael N; Shackelford, Todd K

    2015-01-01

    People judge attractiveness and make trait inferences from the physical appearance of others, and research reveals high agreement among observers making such judgments. Evolutionary psychologists have argued that interest in physical appearance and beauty reflects adaptations that motivate the search for desirable qualities in a potential partner. Although men more than women value the physical appearance of a partner, appearance universally affects social perception in both sexes. Most studies of attractiveness perceptions have focused on third party assessments of static representations of the face and body. Corroborating evidence suggests that body movement, such as dance, also conveys information about mate quality. Here we review evidence that dynamic cues (e.g., gait, dance) also influence perceptions of mate quality, including personality traits, strength, and overall attractiveness. We recommend that attractiveness research considers the informational value of body movement in addition to static cues, to present an integrated perspective on human social perception. PMID:25784887

  18. Integrating Body Movement into Attractiveness Research

    Directory of Open Access Journals (Sweden)

    Bernhard eFink

    2015-03-01

    Full Text Available People judge attractiveness and make trait inferences from the physical appearance of others, and research reveals high agreement among observers making such judgments. Evolutionary psychologists have argued that interest in physical appearance and beauty reflects adaptations that motivate the search for desirable qualities in a potential partner. Although men more than women value the physical appearance of a partner, appearance universally affects social perception in both sexes. Most studies of attractiveness perceptions have focused on third party assessments of static representations of the face and body. Corroborating evidence suggests that body movement, such as dance, also conveys information about mate quality. Here we review evidence that dynamic cues (e.g., gait, dance also influence perceptions of mate quality, including personality traits, strength, and overall attractiveness. We recommend that attractiveness research considers the informational value of body movement in addition to static cues, to present an integrated perspective on human social perception.

  19. Discovery of Linguistic Relations Using Lexical Attraction

    CERN Document Server

    Yuret, D

    1998-01-01

    This work has been motivated by two long term goals: to understand how humans learn language and to build programs that can understand language. Using a representation that makes the relevant features explicit is a prerequisite for successful learning and understanding. Therefore, I chose to represent relations between individual words explicitly in my model. Lexical attraction is defined as the likelihood of such relations. I introduce a new class of probabilistic language models named lexical attraction models which can represent long distance relations between words and I formalize this new class of models using information theory. Within the framework of lexical attraction, I developed an unsupervised language acquisition program that learns to identify linguistic relations in a given sentence. The only explicitly represented linguistic knowledge in the program is lexical attraction. There is no initial grammar or lexicon built in and the only input is raw text. Learning and processing are interdigitated....

  20. Locus of Control and Interpersonal Attraction.

    Science.gov (United States)

    Fagan, M. Michael

    1980-01-01

    The role of locus of control in interpersonal attraction was examined by administering 1) the Nowicki-Strickland Locus of Control Scale and 2) a sociometric test of friendship to 200 eighth graders. (CM)

  1. Redefining the Attraction Measure, Scaling Exponent and Impedance Function of the Gravity Model

    OpenAIRE

    Chen, Yanguang; Xu, Feng

    2013-01-01

    The attraction measure, scaling exponent, and impedance function of the gravity model are redefined using the concepts from fractals and spatial complexity. Firstly, the attraction measure of spatial interaction in human systems is defined by the product of traffic inflow and outflow. Based on the new definition, the gravity model originating from the Newtonian analogy is differentiated from Wilson's spatial interaction model deriving from entropy-maximizing principle. Secondly, the scaling e...

  2. Social Hierarchies with AN Attractive Site Distribution

    Science.gov (United States)

    Naumis, G. G.; Del Castillo-Mussot, M.; Pérez, L. A.; Vázquez, G. J.

    We reinvestigate the model of Bonabeau et al.1 of self-organizing social hierarchies by including a distribution of attractive sites. Agents move randomly except in the case where an attractive site is located in its neighborhood. We find that the transition between an egalitarian society at low population density and a hierarchical one at high population density strongly depends on the distribution and percolation of the valuable sites. We also show how agent diffusivity is closely related to social hierarchy.

  3. Attractions between charged colloids at water interfaces

    OpenAIRE

    Oettel, M.; Dominguez, A; Dietrich, S.

    2005-01-01

    The effective potential between charged colloids trapped at water interfaces is analyzed. It consists of a repulsive electrostatic and an attractive capillary part which asymptotically both show dipole--like behavior. For sufficiently large colloid charges, the capillary attraction dominates at large separations. The total effective potential exhibits a minimum at intermediate separations if the Debye screening length of water and the colloid radius are of comparable size.

  4. Water Density Fluctuations Relevant to Hydrophobic Hydration are Unaltered by Attractions

    CERN Document Server

    Remsing, Richard C

    2014-01-01

    An understanding of density fluctuations in bulk water has made significant contributions to our understanding of the hydration and interactions of idealized, purely repulsive hydrophobic solutes. To similarly inform the hydration of realistic hydrophobic solutes that have dispersive interactions with water, here we characterize water density fluctuations in the presence of attractive fields that correspond to solute-water attractions. We find that when the attractive field acts only in the solute hydration shell, but not in the solute core, it does not significantly alter water density fluctuations in the solute core region. We further find that for a wide range of solute sizes and attraction strengths, the free energetics of turning on the attractive fields in bulk water are accurately captured by linear response theory. Our results also suggest strategies for more efficiently estimating hydration free energies of realistic solutes in bulk water and at interfaces.

  5. Effective super Tonks-Girardeau gases as ground states of strongly attractive multi-component fermions

    OpenAIRE

    Yin, Xiangguo; Guan, Xi-Wen; Batchelor, M. T.; Chen, Shu

    2010-01-01

    In the strong interaction limit, attractive fermions with $N$-component hyperfine states in a one-dimensional waveguide form unbreakable bound cluster states. We demonstrate that the ground state of strongly attractive SU($N$) Fermi gases can be effectively described by a super Tonks-Girardeau gas-like state composed of bosonic cluster states with strongly attractive cluster-cluster interaction for even $N$, and a Fermi duality of a super Tonks-Girardeau gas-like state composed of fermionic c...

  6. Thermodynamics of a lattice gas with linear attractive potential

    Energy Technology Data Exchange (ETDEWEB)

    Pirjol, Dan [Department of Particle Physics, National Institute for Physics and Nuclear Engineering, 077125 Bucharest (Romania); Schat, Carlos [Departamento de Física, FCEyN, Universidad de Buenos Aires and IFIBA, CONICET, Ciudad Universitaria, Pab. 1, 1428 Buenos Aires (Argentina)

    2015-01-15

    We study the equilibrium thermodynamics of a one-dimensional lattice gas with interaction V(|i−j|)=−1/(μn) (ξ−1/n |i−j|) given by the superposition of a universal attractive interaction with strength −1/(μn) ξ<0, and a linear attractive potential 1/(μn{sup 2}) |i−j|. The interaction is rescaled with the lattice size n, such that the thermodynamical limit n → ∞ is well-behaved. The thermodynamical properties of the system can be found exactly, both for a finite size lattice and in the thermodynamical limit n → ∞. The lattice gas can be mapped to a system of non-interacting bosons which are placed on known energy levels. The exact solution shows that the system has a liquid-gas phase transition for ξ > 0. In the large temperature limit T ≫ T{sub 0}(ρ) = ρ{sup 2}/(4μ) with ρ the density, the system becomes spatially homogeneous, and the equation of state is given to a good approximation by a lattice version of the van der Waals equation, with critical temperature T{sub c}{sup (vdW)}=1/(12μ) (3ξ−1)

  7. Freeze Drying of Peptide Drugs Self-Associated with Long-Circulating, Biocompatible and Biodegradable Sterically Stabilized Phospholipid Nanomicelles

    OpenAIRE

    Lim, Sok Bee; Rubinstein, Israel; Önyüksel, Hayat

    2008-01-01

    The purpose of this study was to determine optimal lipid concentration range for lyophilization of sterically stabilized phospholipid nanomicelles (SSM) and the freeze drying feasibility of self-associated therapeutic peptide-SSM assemblies. SSM at 5 to 20 mM 1,2-distearoyl-sn-glycero-3-phosphoethanolamine-N-methoxy-poly(ethylene glycol 2000 (DSPE-PEG2000) were analyzed for particle size and viscosity before and after freeze drying which showed no significant changes (p>0.05). However, a stee...

  8. Attractive forces in microporous carbon electrodes for capacitive deionization

    CERN Document Server

    Biesheuvel, P M; Levi, M; Bazant, M Z

    2013-01-01

    The recently developed modified Donnan (mD) model provides a simple and useful description of the electrical double layer in microporous carbon electrodes, suitable for incorporation in porous electrode theory. By postulating an attractive excess chemical potential for each ion in the micropores that is inversely proportional to the total ion concentration, we show that experimental data for capacitive deionization (CDI) can be accurately predicted over a wide range of applied voltages and salt concentrations. Since the ion spacing and Bjerrum length are each comparable to the micropore size (few nm), we postulate that the attraction results from fluctuating bare Coulomb interactions between individual ions and the metallic pore surfaces (image forces) that are not captured by meanfield theories, such as the Poisson-Boltzmann-Stern model or its mathematical limit for overlapping double layers, the Donnan model. Using reasonable estimates of the micropore permittivity and mean size (and no other fitting parame...

  9. Insulin signaling mediates sexual attractiveness in Drosophila.

    Directory of Open Access Journals (Sweden)

    Tsung-Han Kuo

    Full Text Available Sexually attractive characteristics are often thought to reflect an individual's condition or reproductive potential, but the underlying molecular mechanisms through which they do so are generally unknown. Insulin/insulin-like growth factor signaling (IIS is known to modulate aging, reproduction, and stress resistance in several species and to contribute to variability of these traits in natural populations. Here we show that IIS determines sexual attractiveness in Drosophila through transcriptional regulation of genes involved in the production of cuticular hydrocarbons (CHC, many of which function as pheromones. Using traditional gas chromatography/mass spectrometry (GC/MS together with newly introduced laser desorption/ionization orthogonal time-of-flight mass spectrometry (LDI-MS we establish that CHC profiles are significantly affected by genetic manipulations that target IIS. Manipulations that reduce IIS also reduce attractiveness, while females with increased IIS are significantly more attractive than wild-type animals. IIS effects on attractiveness are mediated by changes in CHC profiles. Insulin signaling influences CHC through pathways that are likely independent of dFOXO and that may involve the nutrient-sensing Target of Rapamycin (TOR pathway. These results suggest that the activity of conserved molecular regulators of longevity and reproductive output may manifest in different species as external characteristics that are perceived as honest indicators of fitness potential.

  10. Understanding talent attraction: The influence of financial rewards elements on perceived job attractiveness

    OpenAIRE

    Anton Schlechter; Angel Hung; Mark Bussin

    2014-01-01

    Orientation: In order to attract knowledge workers and maintain a competitive advantage,it is necessary for organisations to understand how knowledge workers are attracted todifferent types and levels of financial rewards.Research purpose: This research investigated a set of financial reward elements (remuneration, employee benefits and variable pay) to determine whether knowledgeworkers perceived them as attractive inducements when considering a job or position.Motivation for the study: In S...

  11. Self-attracting walk on heterogeneous networks.

    Science.gov (United States)

    Kim, Kanghun; Kyoung, Jaegu; Lee, D-S

    2016-05-01

    Understanding human mobility in cyberspace becomes increasingly important in this information era. While human mobility, memory-dependent and subdiffusive, is well understood in Euclidean space, it remains elusive in random heterogeneous networks like the World Wide Web. Here we study the diffusion characteristics of self-attracting walks, in which a walker is more likely to move to the locations visited previously than to unvisited ones, on scale-free networks. Under strong attraction, the number of distinct visited nodes grows linearly in time with larger coefficients in more heterogeneous networks. More interestingly, crossovers to sublinear growths occur in strongly heterogeneous networks. To understand these phenomena, we investigate the characteristic volumes and topology of the cluster of visited nodes and find that the reinforced attraction to hubs results in expediting exploration first but delaying later, as characterized by the scaling exponents that we derive. Our findings and analysis method can be useful for understanding various diffusion processes mediated by human. PMID:27300913

  12. Social preferences based on sexual attractiveness

    DEFF Research Database (Denmark)

    Brask, Josefine Bohr; Croft, Darren P.; Thompson, Katharine;

    2012-01-01

    with females that are more sexually attractive than themselves and that they perform active partner choices based on this relative attractiveness. We propose that this strategy is likely to represent an important pathway by which females can construct social niches that influence the decision-making of others......Male sexual harassment of females is common across sexually reproducing species and can result in fitness costs to females. We hypothesized that females can reduce unwanted male attention by constructing a social niche where their female associates are more sexually attractive than themselves, thus...... (receptive) female than with another non-receptive female. We then found that, indeed, females exploit this as a strategy to reduce sexual harassment; non-receptive females actively preferred to associate with receptive over non-receptive females. Importantly, when given access only to chemosensory cues, non...

  13. Recognition bias and the physical attractiveness stereotype.

    Science.gov (United States)

    Rohner, Jean-Christophe; Rasmussen, Anders

    2012-06-01

    Previous studies have found a recognition bias for information consistent with the physical attractiveness stereotype (PAS), in which participants believe that they remember that attractive individuals have positive qualities and that unattractive individuals have negative qualities, regardless of what information actually occurred. The purpose of this research was to examine whether recognition bias for PAS congruent information is replicable and invariant across a variety of conditions (i.e. generalizable). The effects of nine different moderator variables were examined in two experiments. With a few exceptions, the effect of PAS congruence on recognition bias was independent of the moderator variables. The results suggest that the tendency to believe that one remembers information consistent with the physical attractiveness stereotype is a robust phenomenon. PMID:22416805

  14. Children and adults use attractiveness as a social cue in real people and avatars.

    Science.gov (United States)

    Principe, Connor P; Langlois, Judith H

    2013-07-01

    Observing social interactions between children and adults is a major method in the toolkit of psychologists who examine social development and social relationships. Although this method has revealed many interesting phenomena, it cannot determine the effect of behavior independent of other traits. Research on the role of attractiveness in social development provides an example of this conundrum: Are attractive and unattractive children/adults treated differently because of their attractiveness (independent of their behavior), do they behave differently and thus elicit differential treatment, or both? Virtual world and avatar-based technologies allow researchers to control the social behaviors of targets; however, whether children and adults use the facial attractiveness of avatars as a social cue in the same way as they do with real peers is currently unknown. Using Mii avatars from the popular Nintendo Wii video game console, Study 1 found that the facial attractiveness ratings of real people strongly predicted the attractiveness ratings of avatar faces based on the former group. Study 2 revealed that adults (n=46) and children (n=42) prefer attractive avatars as social partners. The results of this set of methodological studies may help to clarify future research on the relationship between attractiveness and behavior throughout the lifespan. Furthermore, the use of avatars may allow studies to experimentally examine the effects of attractiveness in situations where such research is not ethical (e.g., peer victimization). PMID:23399311

  15. Steric effects of CO2 binding to transition metal-benzene complexes: A first-principles study

    Science.gov (United States)

    Bae, Hyeonhu; Huang, Bing; Lee, Hoonkyung

    2016-09-01

    Using density functional theory (DFT) calculations, we investigated the adsorption of CO2 molecules on 3d transition metal (TM)-benzene complexes. Our calculations show that the maximum number of CO2 molecules adsorbable on Sc or Ti atoms is three, but the 18-electron rule predicts it should be four. The 18-electron rule is generally successful in predicting the maximum H2 adsorption number for TM atoms including Sc or Ti atoms. We found that the 18-electron rule fails to correctly predict CO2 binding on Sc- or Ti-benzene complexes because CO2 binding, in contrast to H2 binding, requires additional consideration for steric hindrance due to the large bond length of CO2. We calculated the occupation function for CO2 using the Tolman cone angle, which shows that three CO2 molecules fully occupy the available space around Sc- and Ti-benzene complexes. This estimation is the same maximum CO2 adsorption number predicted by DFT calculations. Therefore, we propose that the occupation function for CO2 using the Tolman cone angle is an efficient model for evaluating steric hindrance of CO2 adsorption on a surface.

  16. Photodetachment near an attractive force center

    CERN Document Server

    You, X P

    2014-01-01

    This article studies the photodetachment of a single electron anion near an attractive center. Both the differential and total photodetachment cross section are analysed. We obtain the electron flux crossing through a spherical detector centered at the force center using the semiclassical approximation. The closed-orbit theory gives the total cross section which contains a smooth background and an oscillatory part. Concrete calculations and discussions are carried out for two types of wave source: the $s$- and $p_z$-wave source. Photodetachment processes for three conditions are compared: an anion near an attractive center, near a repulsive center and in a homogeneous electric field.

  17. Improved attractants for enhancing tsetse fly suppression

    International Nuclear Information System (INIS)

    At the initiation of this co-ordinated research project (CRP), the available visually attractant devices and odours for entomological monitoring and for suppression of tsetse fly populations were not equally effective against all economically important tsetse fly species. For species like G. austeni, G. brevipalpis, G. swynnertoni and some species of the PALPALIS-group of tsetse flies no sufficiently effective combinations of visual or odour attractants were available for efficient suppression and standardized monitoring as part of an operational integrated intervention campaign against the tsetse and trypanosomosis (T and T) problem. The Co-ordinated Research Project on Improved Attractants for Enhancing the Efficiency of Tsetse Fly Suppression Operations and Barrier Systems used in Tsetse Control/Eradication Campaigns involved (a) the identification, synthesis and provision of candidate kairomones, their analogues and of dispensers; (b) laboratory screening of synthesised candidate kairomones through electrophysiological studies and wind tunnel experiments; (c) field tests of candidate kairomones alone or as part of odour blends, in combination with available and or new trap designs; and (d) analysis of hydrocarbons that influence tsetse sexual behaviour. The CRP accomplished several main objectives, namely: - The screening of new structurally related compounds, including specific stereoisomers, of known tsetse attractants resulted in the identification of several new candidate odour attractants with promising potential. - An efficient two-step synthetic method was developed for the pilot plant scale production of 3-n-propyphenol, synergistic tsetse kairomone component. - Electrophysiological experiments complemented with wind tunnel studies provided an efficient basis for the laboratory screening of candidate attractants prior to the initiation of laborious field tests. - New traps were identified and modifications of existing traps were tested for some species

  18. Novel Electrostatic Attraction from Plasmon Fluctuations

    OpenAIRE

    Lau, A. W. C.; Levine, Dov; Pincus, P.

    2000-01-01

    In this Letter, we show that at low temperatures, zero-point fluctuations of the plasmon modes of two mutually coupled 2-D planar Wigner crystals give rise to a novel long-range attractive force. For the case where the distance $d$ between two planar surfaces is large, this attractive force has an unusual power-law decay, which scales as $d^{-7/2},$ unlike other fluctuation-induced forces. Specifically, we note that its range is longer than the ``standard'' zero-temperature van der Waals inte...

  19. Human vocal attractiveness as signaled by body size projection.

    Directory of Open Access Journals (Sweden)

    Yi Xu

    Full Text Available Voice, as a secondary sexual characteristic, is known to affect the perceived attractiveness of human individuals. But the underlying mechanism of vocal attractiveness has remained unclear. Here, we presented human listeners with acoustically altered natural sentences and fully synthetic sentences with systematically manipulated pitch, formants and voice quality based on a principle of body size projection reported for animal calls and emotional human vocal expressions. The results show that male listeners preferred a female voice that signals a small body size, with relatively high pitch, wide formant dispersion and breathy voice, while female listeners preferred a male voice that signals a large body size with low pitch and narrow formant dispersion. Interestingly, however, male vocal attractiveness was also enhanced by breathiness, which presumably softened the aggressiveness associated with a large body size. These results, together with the additional finding that the same vocal dimensions also affect emotion judgment, indicate that humans still employ a vocal interaction strategy used in animal calls despite the development of complex language.

  20. Dominant, open nonverbal displays are attractive at zero-acquaintance.

    Science.gov (United States)

    Vacharkulksemsuk, Tanya; Reit, Emily; Khambatta, Poruz; Eastwick, Paul W; Finkel, Eli J; Carney, Dana R

    2016-04-12

    Across two field studies of romantic attraction, we demonstrate that postural expansiveness makes humans more romantically appealing. In a field study (n = 144 speed-dates), we coded nonverbal behaviors associated with liking, love, and dominance. Postural expansiveness-expanding the body in physical space-was most predictive of attraction, with each one-unit increase in coded behavior from the video recordings nearly doubling a person's odds of getting a "yes" response from one's speed-dating partner. In a subsequent field experiment (n = 3,000), we tested the causality of postural expansion (vs. contraction) on attraction using a popular Global Positioning System-based online-dating application. Mate-seekers rapidly flipped through photographs of potential sexual/date partners, selecting those they desired to meet for a date. Mate-seekers were significantly more likely to select partners displaying an expansive (vs. contractive) nonverbal posture. Mediation analyses demonstrate one plausible mechanism through which expansiveness is appealing: Expansiveness makes the dating candidate appear more dominant. In a dating world in which success sometimes is determined by a split-second decision rendered after a brief interaction or exposure to a static photograph, single persons have very little time to make a good impression. Our research suggests that a nonverbal dominance display increases a person's chances of being selected as a potential mate. PMID:27035937

  1. Attractive Hubbard model: Homogeneous Ginzburg-Landau expansion and disorder

    Science.gov (United States)

    Kuchinskii, E. Z.; Kuleeva, N. A.; Sadovskii, M. V.

    2016-02-01

    We derive a Ginzburg-Landau (GL) expansion in the disordered attractive Hubbard model within the combined Nozieres-Schmitt-Rink and DMFT+Σ approximation. Restricting ourselves to the homogeneous expansion, we analyze the disorder dependence of GL expansion coefficients for a wide range of attractive potentials U, from the weak BCS coupling region to the strong-coupling limit, where superconductivity is described by Bose-Einstein condensation (BEC) of preformed Cooper pairs. We show that for the a semielliptic "bare" density of states of the conduction band, the disorder influence on the GL coefficients A and B before quadratic and quartic terms of the order parameter, as well as on the specific heat discontinuity at the superconducting transition, is of a universal nature at any strength of the attractive interaction and is related only to the general widening of the conduction band by disorder. In general, disorder growth increases the values of the coefficients A and B, leading either to a suppression of the specific heat discontinuity (in the weak-coupling limit), or to its significant growth (in the strong-coupling region). However, this behavior actually confirms the validity of the generalized Anderson theorem, because the disorder dependence of the superconducting transition temperature T c, is also controlled only by disorder widening of the conduction band (density of states).

  2. Physical Attractiveness, Attitude Similarity, and Length of Acquaintance as Contributors to Interpersonal Attraction Among Adolescents

    Science.gov (United States)

    Cavior, Norman; And Others

    1975-01-01

    Tenth and twelfth grade males and females who knew each other judged, within grade levels, their classmates on physical attractiveness (PA), perceived attitude similarity (PAS), and interpersonal attraction (IA). Regression analyses supported the hypotheses that PA and PAS are positively correlated. (Author)

  3. Attracting Clients to Service-Oriented Programs.

    Science.gov (United States)

    Disney, Diane M.

    One of a series of manuals developed by the Home and Community-Based Career Education Project, the outreach component publication describes how the project went about attracting clients for its adult vocational counseling services. Sections include: creating a publicity campaign, using an advertising agency, creating products for the mass media,…

  4. Are high-quality mates always attractive?

    Science.gov (United States)

    Holveck, Marie-Jeanne; Verhulst, Simon; Fawcett, Tim W

    2010-01-01

    Sexual selection theory posits that females should choose mates in a way that maximizes their reproductive success. But what exactly is the optimal choice? Most empirical research is based on the assumption that females seek a male of the highest possible quality (in terms of the genes or resources he can provide), and hence show directional preferences for indicators of male quality. This implies that attractiveness and quality should be highly correlated. However, females frequently differ in what they find attractive. New theoretical and empirical insights provide mounting evidence that a female’s own quality biases her judgement of male attractiveness, such that male quality and attractiveness do not always coincide. A recent experiment in songbirds demonstrated for the first time that manipulation of female condition can lead to divergent female preferences, with low-quality females actively preferring low-quality males over high-quality males. This result is in line with theory on state-dependent mate choice and is reminiscent of assortative mating preferences in humans. Here we discuss the implications of this work for the study of mate preferences. PMID:20714411

  5. Stragegies for Attracting and Retaining Teachers

    Science.gov (United States)

    Bland, Paul; Church, Edwin; Luo, Mingchu

    2014-01-01

    Attracting and retaining high quality teachers is a challenge for many school districts. This is especially true in a time of increased accountability and limited resources. This report details best practice in the training, hiring, improvement, and retention of high quality teaching staff. The authors explain how school leaders can attract…

  6. Interpersonal attraction in buyer–supplier relationships

    DEFF Research Database (Denmark)

    Ellegaard, Chris

    2012-01-01

    representing buying and supply companies has yet to be developed. By drawing on social psychology and social exchange literature, this paper attempts to fill some of this gap. It contributes by uncovering the elements and process of interpersonal attraction. Furthermore, propositions are formulated to guide...

  7. Living in Shenzhen: attractive for creatives?

    NARCIS (Netherlands)

    M. Bontje

    2014-01-01

    Like many cities across the globe, Shenzhen is attempting to redevelop itself as a ‘creative city’. This policy concept can mean different things to different people. Strategies aiming at becoming a ‘creative city’ refer to attracting and developing cultural and creative industries like architecture

  8. Sex Attraction in Bactericera cockerelli (Hemiptera: Triozidae)

    Science.gov (United States)

    The potato psyllid, Bactericera (= Paratrioza) cockerelli (Šulc) (Hemiptera: Triozidae), is a major pest of potato. We examined the role of chemical signals in sex attraction, assessing male and female response to male- and female-produced volatile chemicals. In laboratory olfactometer assays, pot...

  9. Do responsible employers attract responsible employees?

    OpenAIRE

    Nyborg, Karine

    2014-01-01

    Survey and register data indicate that many employees prefer a socially responsible employer and will accept a lower wage to achieve this. Laboratory experiments support the hypothesis that socially responsible groups are more productive than others, partly because they attract cooperative types, partly because initial cooperation is reinforced by group dynamics. Overall, the findings indicate corporate social responsibility may have cost advantages for firms.

  10. Prospects for developing attractive magnetic fusion concepts

    International Nuclear Information System (INIS)

    Comments are made pertaining to a generic magnetic fusion reactor study carried out at ORNL. A second study was made of the required reactor characteristics for attractive fusion reactors. The study concluded that both the physics and economics would be achievable with present magnetic configurations

  11. Basins of Attraction for Chimera States

    DEFF Research Database (Denmark)

    Martens, Erik Andreas; Panaggio, Mark; Abrams, Daniel

    2016-01-01

    Chimera states---curious symmetry-broken states in systems of identical coupled oscillators---typically occur only for certain initial conditions. Here we analyze their basins of attraction in a simple system comprised of two populations. Using perturbative analysis and numerical simulation we...

  12. Stereotyping Physical Attractiveness: A Sociocultural Perspective.

    Science.gov (United States)

    Dion, Karen K.; And Others

    1990-01-01

    Studies the tendency to stereotype physical attractiveness and identification in a collectivist culture using a group of 53 Chinese Canadian college students. Finds that introverts tended to be more prone to stereotyping than extroverts. Subjects with the highest cultural involvement were least prone to stereotyping with regard to social…

  13. Ordinal Position, Approval Motivation, and Interpersonal Attraction

    Science.gov (United States)

    Nowicki, Stephen, Jr.

    1971-01-01

    Results of the study suggest that birth-order effects might be included within the wider framework of approval-dependency theory. Females tend to account for a significant share of birth-order effects. More particularly, firstborn females accounted for much of the differences in expressed attraction as well as need for social approval. (Author)

  14. Agreement Attraction in Comprehension: Representations and Processes

    Science.gov (United States)

    Wagers, Matthew W.; Lau, Ellen F.; Phillips, Colin

    2009-01-01

    Much work has demonstrated so-called attraction errors in the production of subject-verb agreement (e.g., "The key to the cabinets are on the table", [Bock, J. K., & Miller, C. A. (1991). "Broken agreement." "Cognitive Psychology, 23", 45-93]), in which a verb erroneously agrees with an intervening noun. Six self-paced reading experiments examined…

  15. Understanding talent attraction: The influence of financial rewards elements on perceived job attractiveness

    Directory of Open Access Journals (Sweden)

    Anton Schlechter

    2014-02-01

    Full Text Available Orientation: In order to attract knowledge workers and maintain a competitive advantage,it is necessary for organisations to understand how knowledge workers are attracted todifferent types and levels of financial rewards.Research purpose: This research investigated a set of financial reward elements (remuneration, employee benefits and variable pay to determine whether knowledgeworkers perceived them as attractive inducements when considering a job or position.Motivation for the study: In South Africa there is a shortage of talent, largely due to highrates of emigration of scarce skills (human capital. Financial rewards or inducementsare necessary to attract talent and it is essential to assess which of these rewards are mostsuccessful in this regard.Method: A 23 full-factorial experimental design (field experiment was used. The threefinancial reward elements (remuneration, employee benefits and variable pay weremanipulated in a fictitious job advertisement (each at two levels. Eight (2 × 2 × 2 = 8 differentversions of a job advertisement were used as a stimulus to determine the effect of financialreward elements on perceived job attractiveness. A questionnaire was used to measure howparticipants perceived the attractiveness of the job. A convenience sampling approach wasused. Different organisations throughout South Africa, as well as corporate members of the South African Reward Association, were asked to participate in the study. Respondents (n = 169 were randomly assigned to the various experimental conditions (i.e. one of the eightadvertisements. Data were analysed using descriptive statistics. A full-factorial analysis ofvariance was used to investigate if significant main effects could be found.Main findings: Participants considered high levels of remuneration, the inclusion ofbenefits and variable pay to be significant job attraction factors within a reward package. Remuneration was found to have the largest main effect on job

  16. The power of change: interpersonal attraction as a function of attitude similarity and attitude alignment.

    Science.gov (United States)

    Reid, Chelsea A; Davis, Jody L; Green, Jeffrey D

    2013-01-01

    Does attitude alignment predict attraction? Would you like a stranger more who shifts her/his attitudes to more closely align with yours? In pairs, participants (N = 77) discussed social issues about which they disagreed and received false feedback on whether the partner engaged in attitude alignment (shifted her/his attitudes toward the participant's attitude) following discussion. Participants also received false feedback about the proportion of similarity to the partner on a set of issues (i.e., 25%, 50%, or 75%). Participants reported greater attraction to partners who engaged in attitude alignment and who were more similar. Moreover, similarity and attitude alignment interacted. Similarity predicted attraction when attitude alignment did not occur, but did not predict attraction when attitude alignment did occur. Finally, partner attitude alignment led to participant attitude alignment, and perceived reasoning ability mediated the attitude alignment-attraction relationship. PMID:24236381

  17. Exploring the influence of steric, electronic and lipophilic descriptors of 1,3-diarly propenones on their anti-inflammatory activity

    Directory of Open Access Journals (Sweden)

    N.M Bhatia

    2010-09-01

    Full Text Available "nBackground and the purpose of the study: Various compounds from natural and synthetic origins containing the 1,3-diarylpropenone structure have been reported to produce a variety of biological activities like anti-microbial, anti-inflammatory, vascular muscle relaxant, etc. A systematic analysis of the structural features responsible for anti-inflammatory activity and a possible mode of their actions were proposed to be evaluated by synthesizing a set of compounds, screening them for anti-inflammatory activity and developing a QSAR model. "nMethods: Two types of 1,3-diarylpropenone derivatives were synthesized employing the Claisen-Schmidt condensation. These compounds were then screened for their in vivo anti-inflammatory activity by the carrageenin induced rat paw edema method and also for in vitro cyclooxygenase-2 (COX-2 inhibition activity using a colorimetric kit for COX (ovine inhibitor screening assay. These derivatives and their anti-inflammatory activity data were employed for QSAR analysis on Vlife MDS 3.5 software. The molecules were divided into training and test sets based on observed activity and QSAR models were generated for the training set and validated. The activity of the molecules of the test set was predicted according to the QSAR equation fit. Possible correlation between observed anti-inflammatory activity and in vitro cyclooxygenase-2 inhibition was also studied. Results and conclusion: Insignificant difference between the observed and predicted biological activity revealed that the selected electronic, steric and lipophilic parameters have a significant correlation (r2 = 0.85 with anti-inflammatory activity of the selected class of compounds. On the basis of results it may be suggested that the 1,3-diaryl-2-propen-1-ones framework is an attractive template for structural optimization to achieve better potency of anti-inflammatory activity. Similarly, the relatively low correlation between anti-inflammatory activity

  18. Observation of attractive and repulsive polarons in a Bose-Einstein condensate

    DEFF Research Database (Denmark)

    Jørgensen, Nils B.; Wacker, Lars; Skalmstang, Kristoffer T.;

    2016-01-01

    for an impurity interacting with a Bose-Einstein condensate (BEC). We measure the energy of the impurity both for attractive and repulsive interactions with the BEC, and find excellent agreement with theories that incorporate three-body correlations, both in the weak-coupling limits and across...

  19. Effects of the steric hindrance of micropores in the hyper-cross-linked polymeric adsorbent on the adsorption of p-nitroaniline in aqueous solution

    International Nuclear Information System (INIS)

    Graphical abstract: The hyper-cross-linked polymeric adsorbents (GQ-05 and GQ-03) with different steric hindrance of micropores were designed. The adsorption capacity and adsorption rate of PNA onto the two adsorbents followed the order GQ-05 > GQ-03. The steric hindrance of micropores was a crucial factor for the adsorption capacity and adsorption rate order. - Highlights: • Two adsorbents with different steric hindrance of micropores were designed. • The adsorption capacity and adsorption rate followed the order GQ-05 > GQ-03. • The steric hindrance of micropores was a crucial factor for the order. - Abstract: A hyper-cross-linked polymeric adsorbent with “-CH2-phenol-CH2-” as the cross-linked bridge (denoted GQ-05), and another hyper-cross-linked polymeric adsorbent with “-CH2-p-cresol-CH2-” as the cross-linked bridge (denoted GQ-03) were synthesized to reveal the effect of the steric hindrance of micropores in the hyper-cross-linked polymeric adsorbent on adsorption capacity and adsorption rate of p-nitroaniline (PNA) from aqueous solution. The results of adsorption kinetics indicated the order of the adsorption rate GQ-05 > GQ-03. The pseudo-first-order rate equation could describe the entire adsorption process of PNA onto GQ-05 while the equation characterized the adsorption process of GQ-03 in two stages. The order of the adsorption capacity GQ-05 > GQ-03 was demonstrated by thermodynamic analysis and dynamic adsorption. The steric hindrance of micropores in the hyper-cross-linked polymeric adsorbent was a crucial factor for the order of the adsorption capacity and adsorption rate

  20. Effects of the steric hindrance of micropores in the hyper-cross-linked polymeric adsorbent on the adsorption of p-nitroaniline in aqueous solution

    Energy Technology Data Exchange (ETDEWEB)

    Xiao, Guqing, E-mail: xiaoguqing2005@163.com; Wen, Ruimin; Wei, Dongmei; Wu, Dan

    2014-09-15

    Graphical abstract: The hyper-cross-linked polymeric adsorbents (GQ-05 and GQ-03) with different steric hindrance of micropores were designed. The adsorption capacity and adsorption rate of PNA onto the two adsorbents followed the order GQ-05 > GQ-03. The steric hindrance of micropores was a crucial factor for the adsorption capacity and adsorption rate order. - Highlights: • Two adsorbents with different steric hindrance of micropores were designed. • The adsorption capacity and adsorption rate followed the order GQ-05 > GQ-03. • The steric hindrance of micropores was a crucial factor for the order. - Abstract: A hyper-cross-linked polymeric adsorbent with “-CH{sub 2}-phenol-CH{sub 2}-” as the cross-linked bridge (denoted GQ-05), and another hyper-cross-linked polymeric adsorbent with “-CH{sub 2}-p-cresol-CH{sub 2}-” as the cross-linked bridge (denoted GQ-03) were synthesized to reveal the effect of the steric hindrance of micropores in the hyper-cross-linked polymeric adsorbent on adsorption capacity and adsorption rate of p-nitroaniline (PNA) from aqueous solution. The results of adsorption kinetics indicated the order of the adsorption rate GQ-05 > GQ-03. The pseudo-first-order rate equation could describe the entire adsorption process of PNA onto GQ-05 while the equation characterized the adsorption process of GQ-03 in two stages. The order of the adsorption capacity GQ-05 > GQ-03 was demonstrated by thermodynamic analysis and dynamic adsorption. The steric hindrance of micropores in the hyper-cross-linked polymeric adsorbent was a crucial factor for the order of the adsorption capacity and adsorption rate.

  1. Does attractiveness influence condom use intentions in heterosexual men? An experimental study

    OpenAIRE

    Eleftheriou, Anastasia; Bullock, Seth; Graham, Cynthia, A.; Stone, Nicole; Ingham, Roger

    2016-01-01

    Objectives: Judgements of attractiveness have been shown to influence the character of social interactions. The present study sought to better understand the relationship between perceived attractiveness, perceived sexual health status and condom use intentions in a heterosexual male population. Setting: The study employed an electronic questionnaire to collect all data, during face-to-face sessions. Participants: 51 heterosexual, English-speaking men aged between 18 and 69?years. ...

  2. Children and Adults use Attractiveness as a Social Cue in Real People and Avatars

    OpenAIRE

    Principe, Connor P.; Langlois, Judith H.

    2013-01-01

    Observing social interactions between children and adults is a major method in the toolkit of psychologists who examine social development and social relationships. Although this method has revealed many interesting phenomena, it cannot determine the effect of behavior independent of other traits. Research on the role of attractiveness in social development provides an example of this conundrum: Are attractive and unattractive children/adults treated differently because of their attractivenes...

  3. Higher-order glass-transition singularities in systems with short-ranged attractive potentials

    OpenAIRE

    Gotze, W.; Sperl, M.

    2002-01-01

    Within the mode-coupling theory for the evolution of structural relaxation, the A_4 glass-transition singularities are identified for systems of particles interacting with a hard-sphere repulsion complemented by different short-ranged potentials: Baxter's singular potential regularized by a large-wave-vector cutoff, a model for the Asakura-Oosawa depletion attraction, a triangular potential, a Yukawa attraction, and a square-well potential. The regular potentials yield critical packing fracti...

  4. Does Attractiveness Influence Condom Use Intentions In Heterosexual Men:An Experimental Study

    OpenAIRE

    Eleftheriou, Anastasia; Bullock, Seth; Graham, Cynthia A.; Stone, Nicole; Ingham, Roger

    2016-01-01

    Objectives: Judgements of attractiveness have been shown to influence the character of social interactions. The present study sought to better understand the relationship between perceived attractiveness, perceived sexual health status and condom use intentions in a heterosexual male population.Setting: The study employed an electronic questionnaire to collect all data, during face-to-face sessions.Participants: 51 heterosexual, English-speaking men aged between 18 and 69 years.Outcome measur...

  5. Retardation turns the van der Waals attraction into a Casimir repulsion as close as 3 nm

    OpenAIRE

    Boström, Mathias; Sernelius, Bo; Brevik, Iver; Ninham, Barry W.

    2012-01-01

    Casimir forces between surfaces immersed in bromobenzene have recently been measured by Munday et al. [Nature (London) 454, 07610 (2009)]. Attractive Casimir forces were found between gold surfaces. The forces were repulsive between gold and silica surfaces. We show the repulsion is due to retardation effects. The van der Waals interaction is attractive at all separations. The retardation-driven repulsion sets in at around 3 nm. To our knowledge, retardation effects have never been found at s...

  6. Darcin: a male pheromone that stimulates female memory and sexual attraction to an individual male's odour

    OpenAIRE

    McLean Lynn; Robertson Duncan H; Davidson Amanda J; Armstrong Stuart D; Simpson Deborah M; Roberts Sarah A; Beynon Robert J; Hurst Jane L

    2010-01-01

    Abstract Background Among invertebrates, specific pheromones elicit inherent (fixed) behavioural responses to coordinate social behaviours such as sexual recognition and attraction. By contrast, the much more complex social odours of mammals provide a broad range of information about the individual owner and stimulate individual-specific responses that are modulated by learning. How do mammals use such odours to coordinate important social interactions such as sexual attraction while allowing...

  7. When do we need attractive-repulsive intermolecular potentials?

    International Nuclear Information System (INIS)

    The role of attractive-repulsive interactions in direct simulation Monte Carlo (DSMC) simulations is studied by comparing with traditional purely repulsive interactions. The larger collision cross section of the long-range LJ potential is shown to result in a higher collision frequency and hence a lower mean free path, by at least a factor of two, for given conditions. This results in a faster relaxation to equilibrium as is shown by comparing the fourth and sixth moments of the molecular velocity distribution obtained using 0-D DSMC simulations. A 1-D Fourier-Couette flow with a large temperature and velocity difference between the walls is used to show that matching transport properties will result in identical solutions using both LJPA and VSS models in the near-continuum regime. However, flows in the transitional regime with Knudsen number, Kn ∼ 0.5 show a dependence on the intermolecular potential in spite of matching the viscosity coefficient due to differences in the collision frequency. Attractive-repulsive potentials should be used when both transport coefficients and collision frequencies should be matched

  8. The role of PEG conformation in mixed layers: from protein corona substrate to steric stabilization avoiding protein adsorption

    Directory of Open Access Journals (Sweden)

    Joan Comenge

    2015-03-01

    Full Text Available Although nanoparticles (NPs have been traditionally modified with a single ligand layer, mixture of ligands might help to combine different functionalities and to further engineer the NP surface. A detailed study of the competition between an alkanethiol (11-mercaptoundecanoic acid and SH-PEG for the surface of AuNPs and the resultant behaviors of this model nanoconjugate is presented here. As a result, the physicochemical properties of these conjugates can be progressively tuned by controlling the composition and especially the conformation of the mixed monolayer. This has implications in the physiological stability. The controlled changes on the SH-PEG conformation rather than its concentration induce a change in the stabilization mechanism from electrostatic repulsion to steric hindrance, which changes the biological fate of NPs. Importantly, the adsorption of proteins on the conjugates can be tailored by tuning the composition and conformation of the mixed layer.

  9. First Principles Calculations for Hydrogenation of Acrolein on Pd and Pt: Chemoselectivity Depends on Steric Effects on the Surface.

    Science.gov (United States)

    Tuokko, Sakari; Pihko, Petri M; Honkala, Karoliina

    2016-01-01

    The chemoselective hydrogenation of acrolein on Pt(111) and Pd(111) surfaces is investigated employing density functional theory calculations. The computed potential energy surfaces together with the analysis of reaction mechanisms demonstrate that steric effects are an important factor that governs chemoselectivity. The reactions at the C=O functionality require more space than the reactions at the C=C functionality. Therefore the formation of allyl alcohol is more favorable at low coverage, while the reduction of the C=C bond and the formation of propanal becomes kinetically more favorable at higher coverage. The elementary reaction steps are found to follow different reaction mechanisms, which are identified according to terminology typically used in organometallic catalysis. The transition state scaling (TSS) relationship is demonstrated and the origin of multiple TSS lines is linked to variation of an internal electronic structure of a carbon skeleton. PMID:26791881

  10. Steric repulsion as a way to achieve the required stability for the preparation of ionic liquid-based ferrofluids.

    Science.gov (United States)

    Rodríguez-Arco, Laura; López-López, Modesto T; González-Caballero, Fernando; Durán, Juan D G

    2011-05-01

    With this work we would like to emphasize the necessity of steric repulsion to stabilize novel ionic liquid-based ferrofluids. For this purpose, we prepared a suspension of magnetite nanoparticles coated with a double layer of oleic acid, dispersed in 1-ethyl-3-methylimidazolium ethylsulphate ([EMIM][EtSO(4)]). For comparison, a suspension of bare magnetite nanoparticles in [EMIM][EtSO(4)] was also prepared. The stability of these suspensions was checked by magnetic sedimentation and centrifugation processes. Furthermore, their yield stress was measured as a function of the applied magnetic field, which gave additional information on their stability. The results of these experiments showed that the suspension of bare nanoparticles was rather unstable, whereas the suspension of double layer coated nanoparticles gave rise to a true (stable) ferrofluid. PMID:21345446

  11. Growth of II-VI thin-films from single-source precursors based on sterically encumbered sitel ligands

    Energy Technology Data Exchange (ETDEWEB)

    Arnold, J.; Seligson, A.L.; Walker, J.M.; Bourret, E.D.; Bonasia, P.J.

    1992-04-01

    We have developed a new route to MOCVD of II-VI compounds based on the use of novel single-source precursors in which the II-VI elements are combined at the molecular level in a single covalent compound. We have prepared and fully characterized a number of new derivatives of zinc, cadmium and mercury incorporating large, sterically demanding tellurolate ligands of general formula: M(sitel){sub 2} where sitel = -TeSi(SiMe{sub 3}){sub 3}. The crystalline compounds are relatively volatile and are easily manipulated under nitrogen. Several of these compounds have been tested for their suitability as precursors in the MOCVD process. Clean pyrolysis reactions and deposition of thin films were achieved. The stoichiometry of the pyrolysis reaction has been determined by analysis of the reaction by-products.

  12. Tax attractiveness and the location of patents

    OpenAIRE

    Dinkel, Andreas; Schanz, Deborah

    2015-01-01

    This paper analyzes the impact of taxation on the location of patents within multinational groups. Based on groups with parents from 36 countries globally and their patent holdings in 36 European countries, we provide insight into the determinants of three subsequent decisions: (1) the decision of whether to locate patents abroad; (2) in which countries to locate patents; and (3) how many patents to locate in each country. Our findings indicate that multinationals take the tax attractiveness ...

  13. Corporate Social Responsibility and Perceived Employer Attractiveness

    OpenAIRE

    Kumar, Adithya

    2013-01-01

    Corporate Social Responsibility (CSR) has been present for several decades and has grown to include several areas in an organisation. The concept has gone on to gain significant importance around the world and has an impact on different sectors within and outside an organisation. This thesis aims to understand how the concept of CSR plays a role in the employer attractiveness and branding of an organisation in the Czech Republic. By analysing the perceptions and opinions of students pursuing ...

  14. Acarine attractants: Chemoreception, bioassay, chemistry and control.

    Science.gov (United States)

    Carr, Ann L; Roe, Michael

    2016-07-01

    The Acari are of significant economic importance in crop production and human and animal health. Acaricides are essential for the control of these pests, but at the same time, the number of available pesticides is limited, especially for applications in animal production. The Acari consist of two major groups, the mites that demonstrate a wide variety of life strategies, i.e., herbivory, predation and ectoparasitism, and ticks which have evolved obligatory hematophagy. The major sites of chemoreception in the acarines are the chelicerae, palps and tarsi on the forelegs. A unifying name, the "foretarsal sensory organ" (FSO), is proposed for the first time in this review for the sensory site on the forelegs of all acarines. The FSO has multiple sensory functions including olfaction, gustation, and heat detection. Preliminary transcriptomic data in ticks suggest that chemoreception in the FSO is achieved by a different mechanism from insects. There are a variety of laboratory and field bioassay methods that have been developed for the identification and characterization of attractants but minimal techniques for electrophysiology studies. Over the past three to four decades, significant progress has been made in the chemistry and analysis of function for acarine attractants in mites and ticks. In mites, attractants include aggregation, immature female, female sex and alarm pheromones; in ticks, the attraction-aggregation-attachment, assembly and sex pheromones; in mites and ticks host kairomones and plant allomones; and in mites, fungal allomones. There are still large gaps in our knowledge of chemical communication in the acarines compared to insects, especially relative to acarine pheromones, and more so for mites than ticks. However, the use of lure-and-kill and lure-enhanced biocontrol strategies has been investigated for tick and mite control, respectively, with significant environmental advantages which warrant further study. PMID:27265828

  15. Domain of attraction in hybrid systems

    OpenAIRE

    Luk, Chuen-kit; 陸傳傑

    2015-01-01

    Domain of Attraction (DoA) is a set of initial conditions for which the system converges to the equilibrium point. In fact, it is a key problem in control engineering to guarantee stability within a workspace and avoid system failures. Classical applications include pendulum systems, tunnel diode circuits, mass-spring systems, negative-resistance oscillators and more recently, these have been found in other fields such as biology and ecology. This thesis firstly addresses the estimation o...

  16. Talent Attraction in Knowledge Intensive Organizations

    OpenAIRE

    Lindahl, Fredrik; Nordkvist, Sven

    2004-01-01

    Background: The forthcoming shortage of labor, due amongst other things to demographical issues and the increasing mobility of people on the labor market, will affect the possibilities to attract and retain employees with valuable key competencies. To win the talent war employer branding has arisen to become a strategy to overcome this threat. Purpose: To investigate and analyze the outside perspective of employer branding – the employer image – of a knowledge intensive organization through ...

  17. Integrating Body Movement into Attractiveness Research

    OpenAIRE

    Bernhard eFink; Bettina eWeege; Nick eNeave; Pham, Michael N.; Shackelford, Todd K.

    2015-01-01

    People judge attractiveness and make trait inferences from the physical appearance of others, and research reveals high agreement among observers making such judgments. Evolutionary psychologists have argued that interest in physical appearance and beauty reflects adaptations that motivate the search for desirable qualities in a potential partner. Although men more than women value the physical appearance of a partner, appearance universally affects social perception in both sexes. Most studi...

  18. Integrating body movement into attractiveness research.

    OpenAIRE

    Fink, Bernhard; Weege, Bettina; Neave, Nick; Pham, Michael N.; Shackelford, Todd K.

    2015-01-01

    People judge attractiveness and make trait inferences from the physical appearance of others, and research reveals high agreement among observers making such judgments. Evolutionary psychologists have argued that interest in physical appearance and beauty reflects adaptations that motivate the search for desirable qualities in a potential partner. Although men more than women value the physical appearance of a partner, appearance universally affects social perception in both sexes. Most studi...

  19. MEXICO Wants to Attract Chinese Tourists

    Institute of Scientific and Technical Information of China (English)

    Audrey GUO

    2009-01-01

    @@ Though last year many countries were affected by the global financial crisis,tourism in Mexico enjoyed an increase of 5% in 2008.Aiming at attracting more Chinese tourists to Mexico,on April 7,2009,Ambassador Jorge Guajardo together with Mr.Eligio Serna,China Director of the Mexico Tourism Board,held a conference to introduce Mexico Travel in Mexico Embassy to China,Beijing.

  20. Equine attraction to essential oil odours

    OpenAIRE

    Hurley, Juliet; Goodwin, Deborah

    2008-01-01

    There are a wide range of products containing essential oils. Aromatherapy for horses is becoming popular with owners however there are few published studies on equine response to essential oil odours. The study aimed to identify which essential oils were attractive to horses. The study comprised 10 horses, (5) geldings, (5) mares of mixed breed. Nine organic essential oils plus a control (no oil) were presented in a repeated measures experimental design. Oils were applied to cotton woo...

  1. Touristic site attractiveness seen through Twitter

    OpenAIRE

    Bassolas, Aleix; Lenormand, Maxime; Tugores, Antònia; Gonçalves, Bruno; Ramasco, José J.

    2016-01-01

    Tourism is becoming a significant contributor to medium and long range travels in an increasingly globalized world. Leisure traveling has an important impact on the local and global economy as well as on the environment. The study of touristic trips is thus raising a considerable interest. In this work, we apply a method to assess the attractiveness of 20 of the most popular touristic sites worldwide using geolocated tweets as a proxy for human mobility. We first rank the touristic sites base...

  2. MODELLING PRODUCTIONS AND ATTRACTIONS OF FREIGHT TRANSPORT

    OpenAIRE

    Zibelnik, Klemen

    2011-01-01

    This diploma thesis addresses the theoretical bases of the regression analysis, identifies the data necessary for the performance of the analysis and modelling of productions and freight transport attractions and examines dependence of European states’ export and import respectively on socio-economic indicators of the states. The focus was limited to the EU Member States and candidate countries for the entry into the EU as well as the available railway and road transport data a...

  3. Malaria Parasites Produce Volatile Mosquito Attractants

    OpenAIRE

    Kelly, Megan; Su, Chih-Ying; Schaber, Chad; Crowley, Jan R.; Hsu, Fong-Fu; Carlson, John R.; Odom, Audrey R.

    2015-01-01

    ABSTRACT The malaria parasite Plasmodium falciparum contains a nonphotosynthetic plastid organelle that possesses plant-like metabolic pathways. Plants use the plastidial isoprenoid biosynthesis pathway to produce volatile odorants, known as terpenes. In this work, we describe the volatile chemical profile of cultured malaria parasites. Among the identified compounds are several plant-like terpenes and terpene derivatives, including known mosquito attractants. We establish the molecular ident...

  4. Stochastic basins of attraction for metastable states

    Science.gov (United States)

    Serdukova, Larissa; Zheng, Yayun; Duan, Jinqiao; Kurths, Jürgen

    2016-07-01

    Basin of attraction of a stable equilibrium point is an effective concept for stability analysis in deterministic systems; however, it does not contain information on the external perturbations that may affect it. Here we introduce the concept of stochastic basin of attraction (SBA) by incorporating a suitable probabilistic notion of basin. We define criteria for the size of the SBA based on the escape probability, which is one of the deterministic quantities that carry dynamical information and can be used to quantify dynamical behavior of the corresponding stochastic basin of attraction. SBA is an efficient tool to describe the metastable phenomena complementing the known exit time, escape probability, or relaxation time. Moreover, the geometric structure of SBA gives additional insight into the system's dynamical behavior, which is important for theoretical and practical reasons. This concept can be used not only in models with small noise intensity but also with noise whose amplitude is proportional or in general is a function of an order parameter. As an application of our main results, we analyze a three potential well system perturbed by two types of noise: Brownian motion and non-Gaussian α-stable Lévy motion. Our main conclusions are that the thermal fluctuations stabilize the metastable system with an asymmetric three-well potential but have the opposite effect for a symmetric one. For Lévy noise with larger jumps and lower jump frequencies ( α = 0.5 ) metastability is enhanced for both symmetric and asymmetric potentials.

  5. Model attraction in medical image object recognition

    Science.gov (United States)

    Tascini, Guido; Zingaretti, Primo

    1995-04-01

    This paper presents as new approach to image recognition based on a general attraction principle. A cognitive recognition is governed by a 'focus on attention' process that concentrates on the visual data subset of task- relevant type only. Our model-based approach combines it with another process, focus on attraction, which concentrates on the transformations of visual data having relevance for the matching. The recognition process is characterized by an intentional evolution of the visual data. This chain of image transformations is viewed as driven by an attraction field that attempts to reduce the distance between the image-point and the model-point in the feature space. The field sources are determined during a learning phase, by supplying the system with a training set. The paper describes a medical interpretation case in the feature space, concerning human skin lesions. The samples of the training set, supplied by the dermatologists, allow the system to learn models of lesions in terms of features such as hue factor, asymmetry factor, and asperity factor. The comparison of the visual data with the model derives the trend of image transformations, allowing a better definition of the given image and its classification. The algorithms are implemented in C language on a PC equipped with Matrox Image Series IM-1280 acquisition and processing boards. The work is now in progress.

  6. NCIPLOT: a program for plotting non-covalent interaction regions

    OpenAIRE

    Contreras-García, Julia; Johnson, Erin R.; Keinan, Shahar; Chaudret, Robin; Piquemal, Jean-Philip; Beratan, David N.; Yang, Weitao

    2011-01-01

    Non-covalent interactions hold the key to understanding many chemical, biological, and technological problems. Describing these non-covalent interactions accurately, including their positions in real space, constitutes a first step in the process of decoupling the complex balance of forces that define non-covalent interactions. Because of the size of macromolecules, the most common approach has been to assign van der Waals interactions (vdW), steric clashes (SC), and hydrogen bonds (HBs) base...

  7. Benzyl acetates as attractants for the male oriental fruit fly, Dacus dorsalis, and the male melon fly, Dacus cucurbitae

    OpenAIRE

    Metcalf, Robert L.; Metcalf, Esther R.; Mitchell, W. C.

    1986-01-01

    Fifty compounds related to benzyl acetate were evaluated quantitatively as attractants to the male oriental fruit fly (Dacus dorsalis) and the male melon fly (Dacus cucurbitae). Thienylmethyl acetate was nearly as attractive as benzyl acetate to both species, but cyclohexylmethyl acetate was completely unattractive, emphasizing the role of the planar aromatic ring in receptor interaction. Although benzyl acetate was equally attractive to both species, para substituents invariably reduced attr...

  8. Interpersonal attraction and personality: what is attractive--self similarity, ideal similarity, complementarity or attachment security?

    Science.gov (United States)

    Klohnen, Eva C; Luo, Shanhong

    2003-10-01

    Little is known about whether personality characteristics influence initial attraction. Because adult attachment differences influence a broad range of relationship processes, the authors examined their role in 3 experimental attraction studies. The authors tested four major attraction hypotheses--self similarity, ideal-self similarity, complementarity, and attachment security--and examined both actual and perceptual factors. Replicated analyses across samples, designs, and manipulations showed that actual security and self similarity predicted attraction. With regard to perceptual factors, ideal similarity, self similarity, and security all were significant predictors. Whereas perceptual ideal and self similarity had incremental predictive power, perceptual security's effects were subsumed by perceptual ideal similarity. Perceptual self similarity fully mediated actual attachment similarity effects, whereas ideal similarity was only a partial mediator. PMID:14561124

  9. Sex attractants for moths of Vietnam: field attraction by synthetic lures baited with known lepidopteran pheromones.

    Science.gov (United States)

    Tran, Van Hai; Pham, Kim Son; Inomata, Shin-ichi; Ando, Tetsu

    2002-07-01

    Screening tests of synthetic lepidopteran sex pheromones were carried out at orchards in the Mekong Delta over an approximately two-year period starting from December 1998. Monoenyl acetates with a C10-C14 chain attracted six species distributed mainly in Southeast Asia: Adoxophyes privatana, Archips atrolucens, and Meridemisfurtiva in the Tortricidae family, and Argyrogramma signata. Spodoptera pectinicornis, and Zonoplusia ochreata in the Noctuidae family. These were in addition to three other noctuid species that had been attracted during previous field examinations within a temperate zone. Furthermore, male moths of three species belonging to the Cosmopterigidae, Gelechiidae, or Batrachedridae family were also caught by traps baited with acetates. Trienes with a C18-C21 chain and their monoepoxides. which are stereotypes of pheromones secreted by females in the Geometridae family, failed to attract any geometrid male, but attracted three Noctuidae species and four Arctiidae species. PMID:12199508

  10. Does attractiveness win? On the gender-specific impact of attractiveness on athletic performance in tennis

    OpenAIRE

    Bakkenbüll, Linn-Brit

    2015-01-01

    This study examines whether there are gender-specific differences in regard to physical attractiveness of professional tennis players and their performance. For this purpose, the top 100 male and female tennis players of the tennis world ranking in 2014 are examined. Athletic performance is measured by prize money earned for single seasons as well as for the whole career. Different OLS-regressions reveal a significantly positive relationship between physical attractiveness and athletic perfor...

  11. How to be an attractive male: floral dimorphism and attractiveness to pollinators in a dioecious plant

    OpenAIRE

    Waelti Marc O; Page Paul A; Widmer Alex; Schiestl Florian P

    2009-01-01

    Abstract Background Sexual selection theory predicts that males are limited in their reproductive success by access to mates, whereas females are more limited by resources. In animal-pollinated plants, attraction of pollinators and successful pollination is crucial for reproductive success. In dioecious plant species, males should thus be selected to increase their attractiveness to pollinators by investing more than females in floral traits that enhance pollinator visitation. We tested the p...

  12. Effects of Surfactants and Polyelectrolytes on the Interaction between a Negatively Charged Surface and a Hydrophobic Polymer Surface.

    Science.gov (United States)

    Rapp, Michael V; Donaldson, Stephen H; Gebbie, Matthew A; Gizaw, Yonas; Koenig, Peter; Roiter, Yuri; Israelachvili, Jacob N

    2015-07-28

    We have measured and characterized how three classes of surface-active molecules self-assemble at, and modulate the interfacial forces between, a negatively charged mica surface and a hydrophobic end-grafted polydimethylsiloxane (PDMS) polymer surface in solution. We provide a broad overview of how chemical and structural properties of surfactant molecules result in different self-assembled structures at polymer and mineral surfaces, by studying three characteristic surfactants: (1) an anionic aliphatic surfactant, sodium dodecyl sulfate (SDS), (2) a cationic aliphatic surfactant, myristyltrimethylammonium bromide (MTAB), and (3) a silicone polyelectrolyte with a long-chain PDMS midblock and multiple cationic end groups. Through surface forces apparatus measurements, we show that the separate addition of three surfactants can result in interaction energies ranging from fully attractive to fully repulsive. Specifically, SDS adsorbs at the PDMS surface as a monolayer and modifies the monotonic electrostatic repulsion to a mica surface. MTAB adsorbs at both the PDMS (as a monolayer) and the mica surface (as a monolayer or bilayer), resulting in concentration-dependent interactions, including a long-range electrostatic repulsion, a short-range steric hydration repulsion, and a short-range hydrophobic attraction. The cationic polyelectrolyte adsorbs as a monolayer on the PDMS and causes a long-range electrostatic attraction to mica, which can be modulated to a monotonic repulsion upon further addition of SDS. Therefore, through judicious selection of surfactants, we show how to modify the magnitude and sign of the interaction energy at different separation distances between hydrophobic and hydrophilic surfaces, which govern the static and kinetic stability of colloidal dispersions. Additionally, we demonstrate how the charge density of silicone polyelectrolytes modifies both their self-assembly at polymer interfaces and the robust adhesion of thin PDMS films to target

  13. 40 CFR 503.33 - Vector attraction reduction.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 29 2010-07-01 2010-07-01 false Vector attraction reduction. 503.33... STANDARDS FOR THE USE OR DISPOSAL OF SEWAGE SLUDGE Pathogens and Vector Attraction Reduction § 503.33 Vector attraction reduction. (a)(1) One of the vector attraction reduction requirements in § 503.33 (b)(1)...

  14. Viewing Attractiveness Socialization from a Social Network Perspective.

    Science.gov (United States)

    Downs, A. Chris

    Providing a framework for a symposium exploring the influence of physical attractiveness on the socialization process, this paper (1) offers a working definition of physical attractiveness, (2) reviews stereotypes associated with attractiveness, and (3) discusses a social network perspective on the influence of attractiveness. Physical…

  15. Darcin: a male pheromone that stimulates female memory and sexual attraction to an individual male's odour

    Directory of Open Access Journals (Sweden)

    McLean Lynn

    2010-06-01

    Full Text Available Abstract Background Among invertebrates, specific pheromones elicit inherent (fixed behavioural responses to coordinate social behaviours such as sexual recognition and attraction. By contrast, the much more complex social odours of mammals provide a broad range of information about the individual owner and stimulate individual-specific responses that are modulated by learning. How do mammals use such odours to coordinate important social interactions such as sexual attraction while allowing for individual-specific choice? We hypothesized that male mouse urine contains a specific pheromonal component that invokes inherent sexual attraction to the scent and which also stimulates female memory and conditions sexual attraction to the airborne odours of an individual scent owner associated with this pheromone. Results Using wild-stock house mice to ensure natural responses that generalize across individual genomes, we identify a single atypical male-specific major urinary protein (MUP of mass 18893Da that invokes a female's inherent sexual attraction to male compared to female urinary scent. Attraction to this protein pheromone, which we named darcin, was as strong as the attraction to intact male urine. Importantly, contact with darcin also stimulated a strong learned attraction to the associated airborne urinary odour of an individual male, such that, subsequently, females were attracted to the airborne scent of that specific individual but not to that of other males. Conclusions This involatile protein is a mammalian male sex pheromone that stimulates a flexible response to individual-specific odours through associative learning and memory, allowing female sexual attraction to be inherent but selective towards particular males. This 'darcin effect' offers a new system to investigate the neural basis of individual-specific memories in the brain and give new insights into the regulation of behaviour in complex social mammals. See associated

  16. Medfly female attractant trapping studies in Guatemala

    International Nuclear Information System (INIS)

    Experiments were conducted from 1994 - 1998 to test the attractiveness of combinations of food-based chemicals for C. capitata (medfly) in Guatemala. Most studies were done in coffee. The 1995 studies, using the FA-2 attractants (ammonium acetate and putrescine) showed that this combination was attractive for females and had potential for use in conjunction with a SIT program. The 1996 studies at three elevations demonstrated that, in general, these attractants, when used in either the Open Bottom Dry Trap (OBDT), Closed Bottom Dry Trap (CBDT), or International Pheromone's McPhail Trap (IPMT) performed better than the Jumbo McPhail trap (JMT) baited with NuLure and borax (NU+B) for capture of feral females. At the high elevation (1400 m), the IPMT with FA-2 and OBDT with FA-2 were best; at the middle elevation (1100 m), the ORDT, IPMT, and CBDT with FA-2 were best; and at low elevations (659 m), the IPMT with FA-2, JMT with NU+B and ORDT with FA-2 were equal in performance. At the middle elevation, using sterile flies, the OBDT with FA-2 worked best. When experiments were carried out in pear, the traps using the FA-2 attractants captured more female flies than the JMT, NU+B, but not significantly more. During the 1997 trials, a third component, trimethylamine was added to the two component lure (FA-3). This attractant was tested in a number of locally produced traps using 2 I soft drink bottles with different color bottoms. The dry versions of the traps contained a yellow sticky insert. All study sites were at low elevation 600 - 650 m, in coffee, testing both sterile and feral flies. With the feral flies during the first phase of the study at finca San Carlos, there were no significant differences between treatments, at finca San Luis, the clear local trap with sticky insert and the green local trap with sticky insert were best, and at finca Valapraiso, the green local trap with yellow sticky insert and yellow local trap with sticky insert captured more flies

  17. Influence of steric hindrance on enantioseparation of Dns-amino acids and pesticides on terguride based chiral selectors in capillary electrophoresis

    Czech Academy of Sciences Publication Activity Database

    Honzátko, Aleš; Cvak, Jan; Vaingátová, Silvie; Flieger, Miroslav

    2005-01-01

    Roč. 28, - (2005), s. 673-677. ISSN 1615-9306 R&D Projects: GA ČR GA203/02/0933 Institutional research plan: CEZ:AV0Z50200510 Keywords : steric hindrance * capillary electrophoresis * pesticides Subject RIV: EE - Microbiology, Virology Impact factor: 1.829, year: 2005

  18. Attraction Effects in Honorific Agreement in Korean

    Science.gov (United States)

    Kwon, Nayoung; Sturt, Patrick

    2016-01-01

    Previous studies have suggested that sentence processing is mediated by content-addressable direct retrieval processes (McElree, 2000; McElree et al., 2003). However, the memory retrieval processes may differ as a function of the type of dependency. For example, while many studies have reported facilitatory intrusion effects associated with a structurally illicit antecedent during the processing of subject-verb number or person agreement and negative polarity items (Pearlmutter et al., 1999; Xiang et al., 2009; Dillon et al., 2013), studies investigating reflexives have not found consistent evidence of intrusion effects (Parker et al., 2015; Sturt and Kwon, 2015; cf. Nicol and Swinney, 1989; Sturt, 2003). Similarly, the memory retrieval processes could be also sensitive to cross-linguistic differences (cf. Lago et al., 2015). We report one self-paced reading experiment and one eye-tracking experiment that examine the processing of subject-verb honorific agreement, a dependency that is different from those that have been studied to date, in Korean, a typologically different language from those previously studied. The overall results suggest that the retrieval processes underlying the processing of subject-verb honorific agreement in Korean are susceptible to facilitatory intrusion effects from a structurally illicit but feature-matching subject, with a pattern that is similar to subject-verb agreement in English. In addition, the attraction effect was not limited to the ungrammatical sentences but was also found in grammatical sentences. The clear attraction effect in the grammatical sentences suggest that the attraction effect does not solely arise as the result of an error-driven process (cf. Wagers et al., 2009), but is likely also to result from general mechanisms of retrieval processes of activating of potential items in memory (Vasishth et al., 2008).

  19. Training program attracts work and health researchers

    DEFF Research Database (Denmark)

    Skakon, Janne

    2007-01-01

    Each year in Canada, the costs of disability arising from work-related causes – including workers’ compensation and health-care costs – exceed $6.7 billion. Despite the significant financial and social impacts of worker injury and illness, only a small fraction of Canadian researchers are dedicated...... to examining work disability prevention issues. An innovative program that attracts international students, the Work Disability Prevention Canadian Institutes of Health Research (CIHR) Strategic Training Program, aims to build research capacity in young researchers and to create a strong network that...

  20. Basins of Attraction for Chimera States

    DEFF Research Database (Denmark)

    Martens, Erik Andreas; Panaggio, Mark; Abrams, Daniel

    2016-01-01

    Chimera states---curious symmetry-broken states in systems of identical coupled oscillators---typically occur only for certain initial conditions. Here we analyze their basins of attraction in a simple system comprised of two populations. Using perturbative analysis and numerical simulation we...... evaluate asymptotic states and associated destination maps, and demonstrate that basins form a complex twisting structure in phase space. Understanding the basins' precise nature may help in the development of control methods to switch between chimera patterns, with possible technological and neural system...

  1. Basins of attraction for chimera states

    Science.gov (United States)

    Martens, Erik A.; Panaggio, Mark J.; Abrams, Daniel M.

    2016-02-01

    Chimera states—curious symmetry-broken states in systems of identical coupled oscillators—typically occur only for certain initial conditions. Here we analyze their basins of attraction in a simple system comprised of two populations. Using perturbative analysis and numerical simulation we evaluate asymptotic states and associated destination maps, and demonstrate that basins form a complex twisting structure in phase space. Understanding the basins’ precise nature may help in the development of control methods to switch between chimera patterns, with possible technological and neural system applications.

  2. How To Attract The Russian Customer

    OpenAIRE

    Nurm, Jana

    2015-01-01

    This bachelor thesis is created for the academic study on International Business and Marketing Logistic at Satakunta University of Applied Sciences (SAMK) in Finland. The main objective of this study is to create possibility for the hotel to enter efficient-ly to the Russian market. The aim of the thesis is to assist company to attract and ob-tain Russian customers’ attention to become stronger and more competitive in the local market in the lowest seasons. The author of the thesis is...

  3. How calcium makes endocytic receptors attractive

    DEFF Research Database (Denmark)

    Andersen, Christian B F; Moestrup, Søren K

    2014-01-01

    receptor. Endosomal acidification and calcium efflux lead to the essential ligand-receptor affinity switch and separation. Recent data, including crystal structures of receptor-ligand complexes, now reveal how calcium, in different types of domain scaffolds, functions in a common way as a removable...... 'lynchpin' that stabilizes favorable positioning of ligand-attractive receptor residues. In addition to explaining how calcium depletion can cause ligand-receptor dissociation, the new data add further insight into how acidification contributes to dissociation through structural changes that affect the...... receptor calcium sites....

  4. Steric Sea Level Change in Twentieth Century Historical Climate Simulation and IPCC-RCP8.5 Scenario Projection: A Comparison of Two Versions of FGOALS Model

    Institute of Scientific and Technical Information of China (English)

    DONG Lu; ZHOU Tianjun

    2013-01-01

    To reveal the steric sea level change in 20th century historical climate simulations and future climate change projections under the IPCC's Representative Concentration Pathway 8.5 (RCP8.5) scenario,the results of two versions of LASG/IAP's Flexible Global Ocean-Atmosphere-Land System model (FGOALS) are analyzed.Both models reasonably reproduce the mean dynamic sea level features,with a spatial pattern correlation coefficient of 0.97 with the observation.Characteristics of steric sea level changes in the 20th century historical climate simulations and RCP8.5 scenario projections are investigated.The results show that,in the 20th century,negative trends covered most parts of the global ocean.Under the RCP8.5 scenario,global-averaged steric sea level exhibits a pronounced rising trend throughout the 21st century and the general rising trend appears in most parts of the global ocean.The magnitude of the changes in the 21st century is much larger than that in the 20th century.By the year 2100,the global-averaged steric sea level anomaly is 18 cm and 10 cm relative to the year 1850 in the second spectral version of FGOALS (FGOALS-s2) and the second grid-point version of FGOALS (FGOALS-g2),respectively.The separate contribution of the thermosteric and halosteric components from various ocean layers is further evaluated.In the 20th century,the steric sea level changes in FGOALS-s2 (FGOALS-g2) are largely attributed to the thermosteric (halosteric) component relative to the pre-industrial control run.In contrast,in the 21st century,the thermosteric component,mainly from the upper 1000 m,dominates the steric sea level change in both models under the RCP8.5 scenario.In addition,the steric sea level change in the marginal sea of China is attributed to the thermosteric component.

  5. Territorial pattern formation in the absence of an attractive potential.

    Science.gov (United States)

    Potts, Jonathan R; Lewis, Mark A

    2016-01-01

    Territoriality is a phenomenon exhibited throughout nature. On the individual level, it is the processes by which organisms exclude others of the same species from certain parts of space. On the population level, it is the segregation of space into separate areas, each used by subsections of the population. Proving mathematically that such individual-level processes can cause observed population-level patterns to form is necessary for linking these two levels of description in a non-speculative way. Previous mathematical analysis has relied upon assuming animals are attracted to a central area. This can either be a fixed geographical point, such as a den- or nest-site, or a region where they have previously visited. However, recent simulation-based studies suggest that this attractive potential is not necessary for territorial pattern formation. Here, we construct a partial differential equation (PDE) model of territorial interactions based on the individual-based model (IBM) from those simulation studies. The resulting PDE does not rely on attraction to spatial locations, but purely on conspecific avoidance, mediated via scent-marking. We show analytically that steady-state patterns can form, as long as (i) the scent does not decay faster than it takes the animal to traverse the terrain, and (ii) the spatial scale over which animals detect scent is incorporated into the PDE. As part of the analysis, we develop a general method for taking the PDE limit of an IBM that avoids destroying any intrinsic spatial scale in the underlying behavioral decisions. PMID:25822451

  6. Attraction-induced dynamical stability of a Bose-Einstein condensate in a nonlinear lattice

    Science.gov (United States)

    Dasgupta, Raka; Venkatesh, B. Prasanna; Watanabe, Gentaro

    2016-06-01

    We study multiple-period Bloch states of a Bose-Einstein condensate with spatially periodic interatomic interaction. Solving the Gross-Pitaevskii equation for the continuum model, and also using a simplified discrete version of it, we investigate the energy-band structures and the corresponding stability properties. We observe an "attraction-induced dynamical stability" mechanism caused by the localization of the density distribution in the attractive domains of the system and the isolation of these higher-density regions. This makes the superfluid stable near the zone boundary and also enhances the stability of higher-periodic states if the nonlinear interaction strength is sufficiently high.

  7. Sugar concentration in nectar: a quantitative metric of crop attractiveness for refined pollinator risk assessments.

    Science.gov (United States)

    Knopper, Loren D; Dan, Tereza; Reisig, Dominic D; Johnson, Josephine D; Bowers, Lisa M

    2016-10-01

    Those involved with pollinator risk assessment know that agricultural crops vary in attractiveness to bees. Intuitively, this means that exposure to agricultural pesticides is likely greatest for attractive plants and lowest for unattractive plants. While crop attractiveness in the risk assessment process has been qualitatively remarked on by some authorities, absent is direction on how to refine the process with quantitative metrics of attractiveness. At a high level, attractiveness of crops to bees appears to depend on several key variables, including but not limited to: floral, olfactory, visual and tactile cues; seasonal availability; physical and behavioral characteristics of the bee; plant and nectar rewards. Notwithstanding the complexities and interactions among these variables, sugar content in nectar stands out as a suitable quantitative metric by which to refine pollinator risk assessments for attractiveness. Provided herein is a proposed way to use sugar nectar concentration to adjust the exposure parameter (with what is called a crop attractiveness factor) in the calculation of risk quotients in order to derive crop-specific tier I assessments. This Perspective is meant to invite discussion on incorporating such changes in the risk assessment process. © 2016 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry. PMID:27197566

  8. Attraction of Investment in Agriculture of Kazakhstan

    Directory of Open Access Journals (Sweden)

    Dinar Abdrakhmanova

    2014-11-01

    Full Text Available Characteristic for conditions competition increase in the market of the investments, interfaced to world financial crisis, makes superrigid deman ds to investment decisions. In similar conditions the exit on the capital markets is one of the key advantages, providing to the enterprises their further development. Attraction of investments is interfaced to a number of difficulties. In connection with shortage of own means for financing of investment activity of the organizations by the basic source of financing there was an extra financing. Necessity of considerable volume of financial resources on development of investment projects does their attraction by a paramount problem of the enterprises-borrowers. Availability of credit sources of financing is limited both because of the high price of the extra capital, and owing to inability of the enterprises-borrowers to interest potential creditors in realization of investment projects. It causes necessity of an economic justification of efficiency and appeal of investment investments. Only having defined, what concrete parameters the company should possess, and having developed concrete ways and indicators of achievement of these parameters, it is possible in modern conditions effectively to develop business. Such aspiration creates investment appeal and is realized by means of basic tools considered in given work.

  9. Potentials-attract or likes-attract in human mate choice in China.

    Directory of Open Access Journals (Sweden)

    Qiao-Qiao He

    Full Text Available To explain how individuals' self-perceived long-term mate value influences their mate preference and mate choice, two hypotheses have been presented, which are "potentials-attract" and "likes-attract", respectively. The potentials-attract means that people choose mates matched with their sex-specific traits indicating reproductive potentials; and the likes-attract means that people choose mates matched with their own conditions. However, the debate about these two hypotheses still remains unsolved. In this paper, we tested these two hypotheses using a human's actual mate choice data from a Chinese online dating system (called the Baihe website, where 27,183 users of Baihe website are included, in which there are 590 paired couples (1180 individuals who met each other via the website. Our main results show that not only the relationship between individuals' own attributes and their self-stated mate preference but also that between individuals' own attributes and their actual mate choice are more consistent with the likes-attract hypothesis, i.e., people tend to choose mates who are similar to themselves in a variety of attributes.

  10. Inverted Cheerios effect: Liquid drops attract or repel by elasto-capillarity

    CERN Document Server

    Karpitschka, S; Lubbers, L A; Weijs, J H; Botto, L; Das, S; Andreotti, B; Snoeijer, J H

    2016-01-01

    Solid particles floating at a liquid interface exhibit a long-ranged attraction mediated by surface tension. In the absence of bulk elasticity, this is the dominant lateral interaction of mechanical origin. Here we show that an analogous long-range interaction occurs between adjacent droplets on solid substrates, which crucially relies on a combination of capillarity and bulk elasticity. We experimentally observe the interaction between droplets on soft gels and provide a theoretical framework that quantitatively predicts the migration velocity of the droplets. Remarkably, we find that while on thick substrates the interaction is purely attractive and leads to drop-drop coalescence, for relatively thin substrates a short-range repulsion occurs which prevents the two drops from coming into direct contact. This versatile, new interaction is the liquid-on-solid analogue of the "Cheerios effect". The effect will strongly influence the condensation and coarsening of drop soft polymer films, and has potential impli...

  11. On-site attractive multiorbital Hamiltonian for d -wave superconductors

    Science.gov (United States)

    Bishop, Christopher B.; Liu, Guangkun; Dagotto, Elbio; Moreo, Adriana

    2016-06-01

    We introduce a two-orbital Hamiltonian on a square lattice that contains on-site attractive interactions involving the two eg orbitals. Via a canonical mean-field procedure similar to the one applied to the well-known negative-U Hubbard model, it is shown that the model develops d -wave (B1 g) superconductivity with nodes along the diagonal directions of the square Brillouin zone. This result is also supported by exact diagonalization of the model in a small cluster. The expectation is that this relatively simple attractive model could be used to address the properties of multiorbital d -wave superconductors in the same manner that the negative-U Hubbard model is widely applied to the study of the properties of s -wave single-orbital superconductors. In particular, we show that by splitting the eg orbitals and working at three-quarters filling, such that the x2-y2 orbital dominates at the Fermi level but the 3 z2-r2 orbital contribution is nonzero, the d -wave pairing state found here phenomenologically reproduces several properties of the superconducting state of the high Tc cuprates.

  12. Sex-Specificity in the Reward Value of Facial Attractiveness.

    Science.gov (United States)

    Hahn, Amanda C; Fisher, Claire I; DeBruine, Lisa M; Jones, Benedict C

    2016-05-01

    Studies of the sex-specificity of sexual arousal in adults (i.e., the tendency to respond more strongly to preferred-sex individuals than non-preferred sex individuals) have suggested that heterosexual men, homosexual men, and homosexual women show stronger sex-specific responses than do heterosexual women. Evidence for a similar pattern of results in studies investigating the reward value of faces is equivocal. Consequently, we investigated the effects of (1) sexual orientation (homosexual vs. heterosexual), (2) sex (male vs. female), (3) image sex (preferred-sex vs. non-preferred-sex), and (4) the physical attractiveness of the individual shown in the image on the reward value of faces. Participants were 130 heterosexual men, 130 homosexual men, 130 heterosexual women, and 130 homosexual women. The reward value of faces was assessed using a standard key-press task. Multilevel modeling of responses indicated that images of preferred-sex individuals were more rewarding than images of non-preferred-sex individuals and that this preferred-sex bias was particularly pronounced when more physically attractive faces were presented. These effects were not qualified by interactions involving either the sexual orientation or the sex of our participants, however, suggesting that the preferred-sex bias in the reward value of faces is similar in heterosexual men, homosexual men, heterosexual women, and homosexual women. PMID:25868402

  13. Self-consistent phonon theory of the crystallization and elasticity of attractive hard spheres.

    Science.gov (United States)

    Shin, Homin; Schweizer, Kenneth S

    2013-02-28

    We propose an Einstein-solid, self-consistent phonon theory for the crystal phase of hard spheres that interact via short-range attractions. The approach is first tested against the known behavior of hard spheres, and then applied to homogeneous particles that interact via short-range square well attractions and the Baxter adhesive hard sphere model. Given the crystal symmetry, packing fraction, and strength and range of attractive interactions, an effective harmonic potential experienced by a particle confined to its Wigner-Seitz cell and corresponding mean square vibrational amplitude are self-consistently calculated. The crystal free energy is then computed and, using separate information about the fluid phase free energy, phase diagrams constructed, including a first-order solid-solid phase transition and its associated critical point. The simple theory qualitatively captures all the many distinctive features of the phase diagram (critical and triple point, crystal-fluid re-entrancy, low-density coexistence curve) as a function of attraction range, and overall is in good semi-quantitative agreement with simulation. Knowledge of the particle localization length allows the crystal shear modulus to be estimated based on elementary ideas. Excellent predictions are obtained for the hard sphere crystal. Expanded and condensed face-centered cubic crystals are found to have qualitatively different elastic responses to varying attraction strength or temperature. As temperature increases, the expanded entropic solid stiffens, while the energy-controlled, fully-bonded dense solid softens. PMID:23464163

  14. Color and scent: how single genes influence pollinator attraction.

    Science.gov (United States)

    Sheehan, H; Hermann, K; Kuhlemeier, C

    2012-01-01

    A major function of angiosperm flowers is the recruitment of animal pollinators that serve to transfer pollen among conspecific plants. Distinct sets of floral characteristics, called pollination syndromes, are correlated with visitation by specific groups of pollinators. Switches among pollination syndromes have occurred in many plant families. Such switches must have involved coordinated changes in multiple traits and multiple genes. Two well-studied floral traits affecting pollinator attraction are petal color and scent production. We review current knowledge about the biosynthetic pathways for floral color and scent production and their interaction at the genetic and biochemical levels. A key question in the field concerns the genes that underlie natural variation in color and scent and how such genes affect pollinator preference, reproductive isolation, and ultimately speciation. PMID:23467550

  15. Understanding attractiveness in business relationships - A complete literature review

    DEFF Research Database (Denmark)

    Mortensen, M. H.

    2012-01-01

    or resolve a particular construct: 1) attraction in the development of buyer-supplier relationships, 2) customer attractiveness to suppliers, and 3) attractiveness in portfolio and key account management. This literature review contributes to the understanding of how knowledge of the power of attraction......The concept of attraction has received surprisingly little attention within business relationship research. Yet, recently, more and more authors have argued that attraction may contribute to the motivation and willingness of a buyer and supplier to engage in and develop a business relationship...

  16. Trip Generation Model Based on Destination Attractiveness

    Institute of Scientific and Technical Information of China (English)

    YAO Liya; GUAN Hongzhi; YAN Hai

    2008-01-01

    Traditional trip generation forecasting methods use unified average trip generation rates to determine trip generation volumes in various traffic zones without considering the individual characteristics of each traffic zone.Therefore,the results can have significant errors.To reduce the forecasting error produced by uniform trip generation rates for different traffic zones,the behavior of each traveler was studied instead of the characteristics of the traffic zone.This paper gives a method for calculating the trip efficiency and the effect of traffic zones combined with a destination selection model based on disaggregate theory for trip generation.Beijing data is used with the trip generation method to predict trip volumes.The results show that the disaggregate model in this paper is more accurate than the traditional method.An analysis of the factors influencing traveler behavior and destination selection shows that the attractiveness of the traffic zone strongly affects the trip generation volume.

  17. Mosquito repellent attracts Culicoides imicola (Diptera: Ceratopogonidae).

    Science.gov (United States)

    Braverman, Y; Chizov-Ginzburg, A; Mullens, B A

    1999-01-01

    A plant-derived mosquito repellent, based on the oil of Eucalyptus maculata var. citriodora Hook, was evaluated against the biting midge Culicoides imicola Kieffer. Suction black light-traps covered with repellent-impregnated polyester mesh and deployed near horses attracted large numbers of C. imicola, which were seen near the treated net within a few minutes of the start of the experiment. Initial collections in the traps were approximately 3 times as large as those in control traps with untreated mesh. Numbers collected in treated traps were similar to untreated control traps after 4 h. Traps with mesh treated with DEET or another plant-derived (Meliaceae) proprietary product, AG1000, acted as repellents relative to the control. The differential activity of repellents against blood-feeding Diptera is discussed. PMID:10071502

  18. Superconducting properties of the attractive Hubbard model

    International Nuclear Information System (INIS)

    A self-consistent set of equations for the one-electron self-energy in the ladder approximation is derived for the attractive Hubbard model in the superconducting state. The equations provide an extension of a T-matrix formalism recently used to study the effect of electron correlations on normal-state properties. An approximation to the set of equations is solved numerically in the intermediate coupling regime, and the one-particle spectral functions are found to have four peaks. This feature is traced back to a peak in the self-energy, which is related to the formation of real-space bound states. For comparison we extend the moment approach to the superconducting state and discuss the crossover from the weak (BCS) to the intermediate coupling regime from the perspective of single-particle spectral densities. (orig.)

  19. Basins of Attraction for Generative Justice

    Science.gov (United States)

    Eglash, Ron; Garvey, Colin

    It has long been known that dynamic systems typically tend towards some state - an "attractor" - into which they finally settle. The introduction of chaos theory has modified our understanding of these attractors: we no longer think of the final "resting state" as necessarily being at rest. In this essay we consider the attractors of social ecologies: the networks of people, technologies and natural resources that makeup our built environments. Following the work of "communitarians" we posit that basins of attraction could be created for social ecologies that foster both environmental sustainability and social justice. We refer to this confluence as "generative justice"; a phrase which references both the "bottom-up", self-generating source of its adaptive meta stability, as well as its grounding in the ethics of egalitarian political theory.

  20. Attractive channel skyrmions and the deuteron

    CERN Document Server

    Leese, R A; Schroers, B J; Leese, R A; Manton, N S; Schroers, B J

    1995-01-01

    The deuteron is described as a quantum state on a ten-dimensional manifold M_{10} of Skyrme fields of degree two, which are obtained by calculating the holonomy of SU(2) instantons. The manifold M_{10} includes both toroidal configurations of minimal energy and configurations which are approximately the product of two Skyrmions in the most attractive relative orientation. The quantum Hamiltonian is of the form -\\Delta +V, where \\Delta is the covariant Laplace operator on M_{10} and V is the potential which M_{10} inherits from the Skyrme potential energy functional. Quantum states are complex-valued functions on the double cover of M_{10} satisfying certain constraints. There is a unique bound state with the quantum numbers of the deuteron, and its binding energy is approximately 6 MeV. Some of the deuteron's electrostatic and magnetostatic properties are also calculated and compared with experiment.

  1. A Model of Lexical Attraction and Repulsion

    CERN Document Server

    Beeferman, D; Lafferty, G D; Beeferman, Doug; Berger, Adam; Lafferty, John

    1997-01-01

    This paper introduces new methods based on exponential families for modeling the correlations between words in text and speech. While previous work assumed the effects of word co-occurrence statistics to be constant over a window of several hundred words, we show that their influence is nonstationary on a much smaller time scale. Empirical data drawn from English and Japanese text, as well as conversational speech, reveals that the ``attraction'' between words decays exponentially, while stylistic and syntactic contraints create a ``repulsion'' between words that discourages close co-occurrence. We show that these characteristics are well described by simple mixture models based on two-stage exponential distributions which can be trained using the EM algorithm. The resulting distance distributions can then be incorporated as penalizing features in an exponential language model.

  2. PROMOTING AND ATTRACTING FOREIGN DIRECT INVESTMENT

    Directory of Open Access Journals (Sweden)

    Elena CHIRILA DONCIU

    2014-09-01

    Full Text Available FDI is an important element of the economic development of any country and its functioning on market principles. They have a great importance for strengthening the economy of countries in transition and their integration into the world’s economy. The modernization of national economies occurs with FDI help, by implementing advanced technologies, know-how sites, the most powerful equipment and the new quality standards by switching to a higher type of growth. The purpose of this research is to identify of the policies to attract and promote FDI, adopted by host countries for foreign investors and are highlighted beneficial aspects of foreign investments flows on recipient economies. The research results show that policies aimed at ensuring access to foreign markets, those that are considering providing commercial facilities and last, but not least, policies focused on tax incentives are very important for foreign investors.

  3. Physician equity alliances: attractive alternatives to PHOs.

    Science.gov (United States)

    Goldstein, D

    1997-04-01

    Physician equity alliances are becoming attractive alternatives to PHOs as integrative models for partnering with physicians, securing managed care contracts and increasing revenue. Unlike many PHOs, these alliances provide mechanisms for asset integration and long-term relationships along with utilization management, sophisticated information systems, access to capital and opportunities for physicians to integrate clinically. There are six major types of physician equity alliances: majority physician-owned, clinic without walls, health system joint venture, publicly held physician practice management company, specialty network, and venture capital. The type of alliance that a physician group practice ultimately develops depends on vision, values, method of capitalization, initial organizer of the alliance, level of involvement of physicians in business issues, corporate structure desired, and characteristics of the managed care market in which the alliance will operate. PMID:10166285

  4. Renewable energy - an attractive marketing proposition

    International Nuclear Information System (INIS)

    The Global Utilities arm of international business consultants PriceWaterhouseCoopers (PWC) has provided a unique insight into the investment plans of Australian utilities regarding renewable energy. PWC has released the findings of a survey of electricity generators and retailers that neatly illustrates the risks and opportunities facing corporations liable under the mandatory renewable energy targets (MRET). Probably the most revealing finding of the PWC report- 'The Future of Australian Renewable Energy' was that the majority of respondents have not yet formulated a comprehensive renewable energy strategy aimed at meeting their obligations under MRET, or maximising the benefit of renewable energy certificates (RECs) produced. Notably, the majority of those surveyed believed that the strongest incentives for investing in new renewable energy generation was the company's 'green image'. In contrast investment characteristics such as low risk returns, the achievement of cost efficiencies or attractive revenue streams were not critical reasons for investing in renewable generation

  5. Interparticle attraction in 2D complex plasmas

    CERN Document Server

    Kompaneets, Roman; Ivlev, Alexei V

    2015-01-01

    Complex (dusty) plasmas allow experimental studies of various physical processes occurring in classical liquids and solids by directly observing individual microparticles. A major problem is that the interaction between microparticles is generally not molecular-like. In this Letter, we propose how to achieve a molecular-like interaction potential in laboratory 2D complex plasmas. We argue that this principal aim can be achieved by using relatively small microparticles and properly adjusting discharge parameters. If experimentally confirmed, this will make it possible to employ complex plasmas as a model system with an interaction potential resembling that of conventional liquids.

  6. Interparticle Attraction in 2D Complex Plasmas

    Science.gov (United States)

    Kompaneets, Roman; Morfill, Gregor E.; Ivlev, Alexei V.

    2016-03-01

    Complex (dusty) plasmas allow experimental studies of various physical processes occurring in classical liquids and solids by directly observing individual microparticles. A major problem is that the interaction between microparticles is generally not molecularlike. In this Letter, we propose how to achieve a molecularlike interaction potential in laboratory 2D complex plasmas. We argue that this principal aim can be achieved by using relatively small microparticles and properly adjusting discharge parameters. If experimentally confirmed, this will make it possible to employ complex plasmas as a model system with an interaction potential resembling that of conventional liquids.

  7. Pheromones mediating copulation and attraction in Drosophila.

    Science.gov (United States)

    Dweck, Hany K M; Ebrahim, Shimaa A M; Thoma, Michael; Mohamed, Ahmed A M; Keesey, Ian W; Trona, Federica; Lavista-Llanos, Sofia; Svatoš, Aleš; Sachse, Silke; Knaden, Markus; Hansson, Bill S

    2015-05-26

    Intraspecific olfactory signals known as pheromones play important roles in insect mating systems. In the model Drosophila melanogaster, a key part of the pheromone-detecting system has remained enigmatic through many years of research in terms of both its behavioral significance and its activating ligands. Here we show that Or47b-and Or88a-expressing olfactory sensory neurons (OSNs) detect the fly-produced odorants methyl laurate (ML), methyl myristate, and methyl palmitate. Fruitless (fru(M))-positive Or47b-expressing OSNs detect ML exclusively, and Or47b- and Or47b-expressing OSNs are required for optimal male copulation behavior. In addition, activation of Or47b-expressing OSNs in the male is sufficient to provide a competitive mating advantage. We further find that the vigorous male courtship displayed toward oenocyte-less flies is attributed to an oenocyte-independent sustained production of the Or47b ligand, ML. In addition, we reveal that Or88a-expressing OSNs respond to all three compounds, and that these neurons are necessary and sufficient for attraction behavior in both males and females. Beyond the OSN level, information regarding the three fly odorants is transferred from the antennal lobe to higher brain centers in two dedicated neural lines. Finally, we find that both Or47b- and Or88a-based systems and their ligands are remarkably conserved over a number of drosophilid species. Taken together, our results close a significant gap in the understanding of the olfactory background to Drosophila mating and attraction behavior; while reproductive isolation barriers between species are created mainly by species-specific signals, the mating enhancing signal in several Drosophila species is conserved. PMID:25964351

  8. Steric effect on the M site of nanolaminate compounds M2SnC (M = Ti, Zr, Hf and Nb)

    International Nuclear Information System (INIS)

    In this paper we report calculations based on an all electron ab initio full-potential linearized augmented plane-wave method using the generalized gradient approximation within the density functional theory to determine the structures of Ti2SnC, Zr2SnC, Hf2SnC and Nb2SnC. The lattice constants obtained after geometry optimization are in good agreement with experimental data. It is observed from these results that there exists a steric effect on the M site. For M atoms with atomic radius (Zr, Hf) larger than that of tin, the polyhedra (octahedron and trigonal prism) constituting the unit cell are less distorted compared to those related to M atoms with atomic radius (Ti, Nb) similar to that of tin. The computed values for the bulk modulus of these ternary carbides are predicted to be about 69% of those of the corresponding binary carbides MC. The analysis of the projected local density of states shows that the major hybrids come from M (M = Ti, Zr, Hf, Nb) d and C p states.

  9. Surface structure of sterically stabilized ferrofluids in a normal magnetic field: grazing-incidence x-ray study.

    Science.gov (United States)

    Vorobiev, A; Gordeev, G; Konovalov, O; Orlova, D

    2009-03-01

    We studied the internal structure of sterically stabilized water- and oil-based ferrofluids in the vicinity of the free interface with a gas by means of x-ray reflectometry and grazing-incidence x-ray diffraction. It was found that in-depth distribution of the magnetic nanoparticles in the layer close to the interface is essentially inhomogeneous. In the case of water-based ferrofluids an enhanced concentration of surfactant and subsequent reduced concentration of the particles were detected in the 100-200-A -thick interface-adjacent layer. Scattering patterns possessing characteristic features of powder diffraction revealed partial ordering of the surfactant in a multilamellar structure. External magnetic fields applied perpendicular to the interface effectively reduced thickness of the depleted layer bringing the particles from the bulk to the surface. However no field-induced correlations between the particles were detected. In the top 500-A -thick layer of an oil-based ferrofluid depletion of the particles density was also present; however, no special arrangement of the surfactant molecules was manifested by the experimental data. Interestingly, for all samples we observed wavy surface deformation appearing in the normal magnetic field of a strength H much smaller than the critical values H_{c} calculated according to the conventional theory of ferrofluid surface instability. This deformation with lateral periodicity of a few millimeters has an amplitude smoothly increasing up to a few microns at H=0.5H_{c} . PMID:19391940

  10. Nano composites Based on Technical Polymers and Sterically Functionalized Soft Magnetic Magnetite Nanoparticles: Synthesis, Processing, and Characterization

    International Nuclear Information System (INIS)

    This experimental study deals with the synthesis, processing, and characterization of highly filled nano composites based on polyvinyl butyral/magnetite (PVB/Fe3O4) and polymethylmethacrylate /magnetite (PMMA/Fe3O4). The nanoparticles are synthesized in an aqueous coprecipitation reaction and show a single particle diameter of approximately 15 nm. The particles are sterically functionalized and covered by PVB and PMMA in a spray drying process. The synthesized compound particles are further processed by injection molding to test specimens with filler contents up to 14.5 vol.-%. PVB and PMMA specimen are processed as a reference as well. The distribution of the nanoparticles is characterized by microscopy. Besides a minor number of agglomerates and aggregates the nanoparticles are distributed homogeneously in the PVB composites. Furthermore, the injection molded specimens are characterized with regard to their thermal degradation, polymer structure, and their mechanical and magnetic properties. The presence of nanoparticles capped with ricinoleic acid shows significant decrease in degradation temperature and in glass transition temperature of PVB. The degradation temperature of PMMA is increased by adding nanoparticles capped with oleic acid. Dynamic-mechanical properties as well as the magnetic permeability of PVB and PMMA are improved significantly by adding nanoparticles

  11. Steric Interference of Adhesion Supports In-Vitro Chondrogenesis of Mesenchymal Stem Cells on Hydrogels for Cartilage Repair

    Science.gov (United States)

    Goldshmid, Revital; Cohen, Shlomit; Shachaf, Yonatan; Kupershmit, Ilana; Sarig-Nadir, Offra; Seliktar, Dror; Wechsler, Roni

    2015-01-01

    Recent studies suggest the presence of cell adhesion motifs found in structural proteins can inhibit chondrogenesis. In this context, the current study aims to determine if a polyethylene glycol (PEG)-modified fibrinogen matrix could support better chondrogenesis of human bone marrow mesenchymal stem cells (BM-MSC) based on steric interference of adhesion, when compared to a natural fibrin matrix. Hydrogels used as substrates for two-dimensional (2D) BM-MSC cultures under chondrogenic conditions were made from cross-linked PEG-fibrinogen (PF) and compared to thrombin-activated fibrin. Cell morphology, protein expression, DNA and sulfated proteoglycan (GAG) content were correlated to substrate properties such as stiffness and adhesiveness. Cell aggregation and chondrogenic markers, including collagen II and aggrecan, were observed on all PF substrates but not on fibrin. Shielding fibrinogen’s adhesion domains and increasing stiffness of the material are likely contributing factors that cause the BM-MSCs to display a more chondrogenic phenotype. One composition of PF corresponding to GelrinC™—a product cleared in the EU for cartilage repair—was found to be optimal for supporting chondrogenic differentiation of BM-MSC while minimizing hypertrophy (collagen X). These findings suggest that semi-synthetic biomaterials based on ECM proteins can be designed to favourably affect BM-MSC towards repair processes involving chondrogenesis. PMID:26411496

  12. Surface structure of sterically stabilized ferrofluids in a normal magnetic field: Grazing-incidence x-ray study

    Science.gov (United States)

    Vorobiev, A.; Gordeev, G.; Konovalov, O.; Orlova, D.

    2009-03-01

    We studied the internal structure of sterically stabilized water- and oil-based ferrofluids in the vicinity of the free interface with a gas by means of x-ray reflectometry and grazing-incidence x-ray diffraction. It was found that in-depth distribution of the magnetic nanoparticles in the layer close to the interface is essentially inhomogeneous. In the case of water-based ferrofluids an enhanced concentration of surfactant and subsequent reduced concentration of the particles were detected in the 100-200-Å -thick interface-adjacent layer. Scattering patterns possessing characteristic features of powder diffraction revealed partial ordering of the surfactant in a multilamellar structure. External magnetic fields applied perpendicular to the interface effectively reduced thickness of the depleted layer bringing the particles from the bulk to the surface. However no field-induced correlations between the particles were detected. In the top 500-Å -thick layer of an oil-based ferrofluid depletion of the particles density was also present; however, no special arrangement of the surfactant molecules was manifested by the experimental data. Interestingly, for all samples we observed wavy surface deformation appearing in the normal magnetic field of a strength H much smaller than the critical values Hc calculated according to the conventional theory of ferrofluid surface instability. This deformation with lateral periodicity of a few millimeters has an amplitude smoothly increasing up to a few microns at H=0.5Hc .

  13. Steric effects of CO2 binding to transition metal-benzene complexes: a first-principles study

    CERN Document Server

    Bae, Hyeonhu; Lee, Hoonkyung

    2016-01-01

    Using density functional theory (DFT) calculations, we investigated the adsorption of CO2 molecules on 3d transition metal (TM)-benzene complexes. Our calculations show that the maximum number of CO2 molecules adsorbable on Sc or Ti atoms is three, but the 18-electron rule predicts it should be four. The 18-electron rule is generally successful in predicting the maximum H2 adsorption number for TM atoms including Sc or Ti atoms. We found that the 18-electron rule fails to correctly predict CO2 binding on Sc- or Ti-benzene complexes because CO2 binding, in contrast to H2 binding, requires additional consideration for steric hindrance due to the large bond length of CO2. We calculated the occupation function for CO2 using the Tolman cone angle, which shows that three CO2 molecules fully occupy the available space around Sc- and Ti-benzene complexes. This estimation is the same maximum CO2 adsorption number predicted by DFT calculations. Therefore, we propose that the occupation function for CO2 using the Tolman...

  14. Thermodynamic study of aqueous 2-(isopropylamino)ethanol. A sterically hindered new amine absorbent for CO2 capture

    International Nuclear Information System (INIS)

    Highlights: • Density and ultrasound speeds were measured in 38 aqueous mixtures of 2-(isopropylamino)ethanol. • Excess molar and limiting molar and partial molar properties were derived and interpreted. • Temperature and composition derivatives of different order give relevant hydration and molecular aggregation information. • A quantitative measure of the screening effect to the H-bonding ability of the amine group is proposed. - Abstract: Simultaneous measurements of density and sound speed, at five temperatures, T = (283.15 to 303.15) K and over the whole composition range were performed in 38 aqueous mixtures of 2-(isopropylamino)ethanol (IPAE), a sterically hindered amine of new generation with potential use in CO2 capture. Composition and temperature effects on different molar, excess molar, apparent molar and partial molar properties such as volume, isobaric expansion and isentropic compression are analysed, in order to assess different changes in the hydration and association patterns, across the entire composition range. A quantitative measure of the screening effect produced by the bulky hydrophobic part of IPAE to the H-bonding ability of the –NH group to the water molecules, is proposed. A comparison of the different thermodynamic properties, derived for this system, with those for the aqueous system of 2-(ethylamino)ethanol (EEA), is made. This last compound has a common structural –NHCH2CH2OH group sequence and a smaller and linear hydrophobic part

  15. How to be an attractive male: floral dimorphism and attractiveness to pollinators in a dioecious plant

    Directory of Open Access Journals (Sweden)

    Waelti Marc O

    2009-08-01

    Full Text Available Abstract Background Sexual selection theory predicts that males are limited in their reproductive success by access to mates, whereas females are more limited by resources. In animal-pollinated plants, attraction of pollinators and successful pollination is crucial for reproductive success. In dioecious plant species, males should thus be selected to increase their attractiveness to pollinators by investing more than females in floral traits that enhance pollinator visitation. We tested the prediction of higher attractiveness of male flowers in the dioecious, moth-pollinated herb Silene latifolia, by investigating floral signals (floral display and fragrance and conducting behavioral experiments with the pollinator-moth, Hadena bicruris. Results As found in previous studies, male plants produced more but smaller flowers. Male flowers, however, emitted significantly larger amounts of scent than female flowers, especially of the pollinator-attracting compounds. In behavioral tests we showed that naïve pollinator-moths preferred male over female flowers, but this preference was only significant for male moths. Conclusion Our data suggest the evolution of dimorphic floral signals is shaped by sexual selection and pollinator preferences, causing sexual conflict in both plants and pollinators.

  16. Influence of nonelectrostatic ion-ion interactions on double-layer capacitance

    Science.gov (United States)

    Zhao, Hui

    2012-11-01

    Recently a Poisson-Helmholtz-Boltzmann (PHB) model [Bohinc , Phys. Rev. EPLEEE81539-375510.1103/PhysRevE.85.031130 85, 031130 (2012)] was developed by accounting for solvent-mediated nonelectrostatic ion-ion interactions. Nonelectrostatic interactions are described by a Yukawa-like pair potential. In the present work, we modify the PHB model by adding steric effects (finite ion size) into the free energy to derive governing equations. The modified PHB model is capable of capturing both ion specificity and ion crowding. This modified model is then employed to study the capacitance of the double layer. More specifically, we focus on the influence of nonelectrostatic ion-ion interactions on charging a double layer near a flat surface in the presence of steric effects. We numerically compute the differential capacitance as a function of the voltage under various conditions. At small voltages and low salt concentrations (dilute solution), we find out that the predictions from the modified PHB model are the same as those from the classical Poisson-Boltzmann theory, indicating that nonelectrostatic ion-ion interactions and steric effects are negligible. At moderate voltages, nonelectrostatic ion-ion interactions play an important role in determining the differential capacitance. Generally speaking, nonelectrostatic interactions decrease the capacitance because of additional nonelectrostatic repulsion among excess counterions inside the double layer. However, increasing the voltage gradually favors steric effects, which induce a condensed layer with crowding of counterions near the electrode. Accordingly, the predictions from the modified PHB model collapse onto those computed by the modified Poisson-Boltzmann theory considering steric effects alone. Finally, theoretical predictions are compared and favorably agree with experimental data, in particular, in concentrated solutions, leading one to conclude that the modified PHB model adequately predicts the diffuse

  17. Role of Physical Attractiveness in Peer Attribution of Psychological Disturbance

    Science.gov (United States)

    Cash, Thomas F.; And Others

    1977-01-01

    The physical attractiveness stereotype was examined as it pertains to the attribution of psychological disturbance among peers. Consistent with the stereotype, attractive interviewees were judged as less disturbed with better prognosis than unattractive interviewees. (Author)

  18. Self-Disclosure Flexibility, Empathy, and Perceptions of Adjustment and Attraction.

    Science.gov (United States)

    Neimeyer, Greg J.; Banikiotes, Paul G.

    1981-01-01

    Self-disclosure flexibility has been associated with social perceptiveness and empathy. This study tested the generalizability of the social perceptiveness hypothesis to in-vivo interactions. Findings indicated that greater flexibility is associated with higher levels of empathy and interpersonal attraction in structured settings. (Author/RC)

  19. Therapeugenic Factors in Psychotherapy: The Effect of Attitude Similarity on Therapist Credibility and Attraction.

    Science.gov (United States)

    Trautt, Gregory M.; And Others

    1980-01-01

    The therapist with similar attitudes was seen as more qualified, higher in interpersonal attraction, and more likeable. Subjects were more willing to recommend or seek therapy from these therapists. Significant interaction indicated that male subjects were more affected by the degree of attitude similarity. (Author)

  20. On the Ephemeral Nature of the Relationship between Attitude Similarity and Interpersonal Attraction during Initial Encounters.

    Science.gov (United States)

    Sunnafrank, Michael J.; Miller, Gerald R.

    A study was conducted to identify the independent and conjoint influence of attitude similarity and initial interactions on interpersonal attraction to relative strangers. The 124 college students who were participants in the study were informed that they would be working on a project with either an attitudinally similar or dissimilar stranger…

  1. Spin Symmetry in Dirac-Attractive Radial Problem and Tensor Potential

    Institute of Scientific and Technical Information of China (English)

    M. Eshghit; M. Hamzavi

    2012-01-01

    In this paper, we solve the Dirac equation under spin symmetry limit for attractive radial potential including a Coulomb-like tensor interaction. By using the parametric generalization of the Nikiforov-Uvarov method, the energy eigenvalues equation and the corresponding wave functions have been obtained in closed forms. Some numerical results are given too.

  2. attracting antagonists: does floral nectar increase leaf herbivory?

    OpenAIRE

    Adler, L.S.; Bronstein, J. L.

    2004-01-01

    Traits that are attractive to mutualists may also attract antagonists, resulting in conflicting selection pressures. Here we develop the idea that increased floral nectar production can, in some cases, increase herbivory. In these situations, selection for increased nectar production to attract pollinators may be constrained by a linked cost of herbivore attraction. In support of this hypothesis, we report that experimentally supplementing nectar rewards in Datura stramonium led to increased ...

  3. Coffee attraction experiences: A narrative sStudy

    OpenAIRE

    Kleidas, Minos; Jolliffe, Lee

    2010-01-01

    Reflecting a rich global coffee culture this paper explores the experience of visitors to coffee attractions as reflected through travel narratives published in the coffee trade literature. It first positions coffee related tourism within culinary tourism and then examines the types of attractions related to coffee. Using a typology of coffee attractions derived from the literature on both attractions and coffee travel narratives from five specialized coffee periodicals are reviewed. In doing...

  4. Smile attractiveness. Self-perception and influence on personality.

    NARCIS (Netherlands)

    Geld, P. van der; Oosterveld, P.; Heck, G.L. van; Kuijpers-Jagtman, A.M.

    2007-01-01

    OBJECTIVES: To investigate self-perception of smile attractiveness and to determine the role of smile line and other aspects correlated with smile attractiveness and their influence on personality traits. SUBJECTS AND METHODS: Participants judged their smile attractiveness with a patient-specific qu

  5. Somatic Attractiveness: As in Other Things, Moderation is Best.

    Science.gov (United States)

    Freeman, Harvey R.

    1985-01-01

    Investigated whether a physical attractiveness stereotype exists when "attractive" is defined in terms of physique and "positive" is defined in terms of sex role characteristics and future life happiness. Sex role and life happiness were rated highest for those of intermediate attractiveness. Results for somatic beauty are discussed. (Author/BL)

  6. Physical Attractiveness, Opportunity, and Success in Everyday Exchange.

    Science.gov (United States)

    Mulford, Matthew; Orbell, John; Shatto, Catherine; Stockard, Jean

    1998-01-01

    Addresses the role of perceived physical attractiveness in everyday exchange. Indicates that decisions to enter into play and to cooperate with others is directly related to individuals' perceptions of others' attractiveness, but that individuals' perceptions of their own attractiveness affects men's and women's decisions differently. Suggests…

  7. THE NEUROBIOLOGICAL, SOCIAL AND EVOLUTIONARY ASPECTS OF INTER PERSONAL ATTRACTION

    Directory of Open Access Journals (Sweden)

    Smrithi

    2015-03-01

    Full Text Available Interpersonal Attraction is the attraction between two people, which leads to friendships and even romantic relationships. Although Interpersonal Attraction has been a long - standing concept, only recently it is being studied regarding its neurobiological and socio evolutionary basis. It is now a major area of research in Social as well as Evolutionary Psychology.

  8. THE NEUROBIOLOGICAL, SOCIAL AND EVOLUTIONARY ASPECTS OF INTER PERSONAL ATTRACTION

    OpenAIRE

    Smrithi; Devdas; Ashok; Meghashree; Aarathi

    2015-01-01

    Interpersonal Attraction is the attraction between two people, which leads to friendships and even romantic relationships. Although Interpersonal Attraction has been a long - standing concept, only recently it is being studied regarding its neurobiological and socio evolutionary basis. It is now a major area of research in Social as well as Evolutionary Psychology.

  9. EVALUATION OF FLORAL CHARACTERISTICS OF MELON HYBRIDS (Cucumis melo L.) IN POLLINATOR ATTRACTIVENESS

    OpenAIRE

    LÚCIA HELENA PIEDADE KIILL; EDSÂNGELA DE ARAÚJO FEITOZA; KÁTIA MARIA MEDEIROS DE SIQUEIRA; MÁRCIA DE FÁTIMA RIBEIRO; EVA MÔNICA SARMENTO DA SILVA

    2016-01-01

    ABSTRACT Floral morphology and biology are important characteristics for plant-pollinator interactions and may influence the behavior of these agents. This study aimed to determine which floral attributes of different melon hybrids influence this interaction and, consequently, their attractiveness in simultaneous crops. The study was conducted in the region of Petrolina, State of Pernambuco (PE)/Juazeiro, State of Bahia (BA) and Mossoró, State of Rio Grande do Norte (RN), in areas with the f...

  10. On energetic prerequisites of attracting electrons

    International Nuclear Information System (INIS)

    The internal reorganization energy and the zero-point vibrational energy (ZPE) of fractionally charged molecules embedded in molecular materials are discussed. The theory for isolated open quantum systems is taken as the starting point. It is shown that for isolated molecules the internal reorganization-energy function and its slope, i.e., the chemical potential of an open molecular system are monotonically decreasing functions with respect to increasing amount of negative excess charge (q) in the range of q = [0, 1]. Calculations of the ZPE for fractionally charged molecules show that the ZPE may have a minimum for fractional occupation. The calculations show that the internal reorganization energy and changes in the ZPE are of the same order of magnitude with different behavior as a function of the excess charge. The sum of the contributions might favor molecules with fractional occupation of the molecular units and partial delocalization of the excess electrons in solid-state materials also when considering Coulomb repulsion between the excess electrons. The fractional electrons are then coherently distributed on many molecules of the solid-state material forming a condensate of attracting electrons, which is crucial for the superconducting state

  11. Touristic site attractiveness seen through Twitter

    CERN Document Server

    Bassolas, Aleix; Gonçalves, Bruno; Tugores, Antònia; Ramasco, José J

    2016-01-01

    Tourism is a significant contributor to medium and long range travels in an increasingly globalized world. Leisure travel has an important impact on the local and global economy and on the environment as well. The study of touristic trips is thus raising a considerable interest. In this work, we apply a method to assess the attractiveness of 20 of the most popular touristic sites worldwide using geolocated tweets as a proxy for human mobility. We first rank the touristic sites according to the spatial distribution of their visitors' place of residence. The Taj Mahal, the Pisa Tower and the Eiffel Tower appear consistently in the top 5 in these rankings. We then consider a coarser scale and classify the travelers by country of residence. Touristic site's visiting figures are then studied by country of residence showing that the Eiffel Tower, Times Square and the London Tower welcome the majority of the visitors of each country. Finally, we build a network linking sites whenever a user has been detected in more...

  12. Discovering Attractive Products based on Influence Sets

    CERN Document Server

    Arvanitis, Anastasios

    2011-01-01

    Skyline queries have been widely used as a practical tool for multi-criteria decision analysis and for applications involving preference queries. For example, in a typical online retail application, skyline queries can help customers select the most interesting, among a pool of available, products. Recently, reverse skyline queries have been proposed, highlighting the manufacturer's perspective, i.e. how to determine the expected buyers of a given product. In this work we develop novel algorithms for two important classes of queries involving customer preferences. We first propose a novel algorithm, termed as RSA, for answering reverse skyline queries. We then introduce a new type of queries, namely the k-Most Attractive Candidates k-MAC query. In this type of queries, given a set of existing product specifications P, a set of customer preferences C and a set of new candidate products Q, the k-MAC query returns the set of k candidate products from Q that jointly maximizes the total number of expected buyers, ...

  13. Effects of water-channel attractions on single-file water permeation through nanochannels

    Science.gov (United States)

    Xu, Yousheng; Tian, Xingling; Lv, Mei; Deng, Maolin; He, Bing; Xiu, Peng; Tu, Yusong; Zheng, Youqu

    2016-07-01

    Single-file transportation of water across narrow nanochannels such as carbon nanotubes has attracted much attention in recent years. Such permeation can be greatly affected by the water-channel interactions; despite some progress, this issue has not been fully explored. Herein we use molecular dynamics simulations to investigate the effects of water-channel attractions on occupancy, translational (transportation) and orientational dynamics of water inside narrow single-walled carbon nanotubes (SWNTs). We use SWNTs as the model nanochannels and change the strength of water-nanotube attractions to mimic the changes in the hydrophobicity/polarity of the nanochannel. We investigate the dependence of water occupancy inside SWNTs on the water-channel attraction and identify the corresponding threshold values for drying states, wetting-drying transition states, and stably wetting states. As the strength of water-channel attractions increases, water flow increases rapidly first, and then decreases gradually; the maximal flow occurs in the case where the nanochannel is predominately filled with the 1D water wire but with a small fraction of ‘empty states’, indicating that appropriate empty-filling (drying-wetting) switching can promote water permeation. This maximal flow is unexpected, since in traditional view, the stable and tight hydrogen-bonding network of the water wire is the prerequisite for high permeability of water. The underlying mechanism is discussed from an energetic perspective. In addition, the effect of water-channel attractions on reorientational dynamics of the water wire is studied, and a negative correlation between the flipping frequency of water wire and the water-channel attraction is observed. The underlying mechanism is interpreted in term of the axial total dipole moment of inner water molecules. This work would help to better understand the effects of water-channel attractions on wetting properties of narrow nanochannels, and on single

  14. Re-evaluating the role of sterics and electronic coupling in determining the open-circuit voltage of organic solar cells

    KAUST Repository

    Graham, Kenneth

    2013-07-30

    The effects of sterics and molecular orientation on the open-circuit voltage and absorbance properties of charge-transfer states are explored in model bilayer organic photovoltaics. It is shown that the open-circuit voltage correlates linearly with the charge-transfer state energy and is not significantly influenced by electronic coupling. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  15. Attracting Students to the Field of Measurement

    Science.gov (United States)

    Finney, Sara J.; Pastor, Dena A.

    2012-01-01

    To address the shortage of professionals in measurement, it is essential that we make young career-seekers aware that measurement is an option as a profession. In this paper, we discuss how creating a strong pipeline of students into our field involves personal interactions between faculty representing the graduate programs in measurement and…

  16. Phospholipids chiral at phosphorus. Steric course of the reactions catalyzed by phosphatidylserine synthase from Escherichia coli and yeast

    International Nuclear Information System (INIS)

    The steric courses of the reactions catalyzed by phosphatidylserine (PS) synthase from Escherichia coli and yeast were elucidated by the following procedure. R/sub P/ and S/sub P/ isomers of 1,2-dipalmitoyl-sn-glycero-3-[17O, 18O]phosphoethanolamine ([17O, 18O]DPPE) were synthesized and converted to (R/sub P/)- and (S/sub P/)-1,2-dipalmitoyl-sn-glycero-3-[16O, 17O, 18O]DPPA), respectively, by incubating with phospholipase D. Condensation of [16O, 17O, 18O]DPPA with cytidine 5'-monophosphomorpholidate in pyridine gave the desired substrate for PS synthase, [17O, 18O]cytidine 5'-diphospho-1,2-dipalmitoyl-sn-glycerol ([17O,18O]CDP-DPG), as a mixture of several isotopic and configurational isomers. Incubation of [17O, 18O]CDP-DPG), as a mixture of several isotopic and configurational isomers. Incubation of [17O, 18O] CDP-DPG with a mixture of L-serine, PS synthase and PS decarboxylase gave [17O, 18O]DPPE. The configuration and isotopic enrichments of the starting [17O, 18O]DPPE and the product were analyzed by 31P NMR following trimethylsilylation of the DPPE. The results indicate that the reaction of E. coli PS synthase proceeds with retention of configuration at phosphorus, which suggests a two-step mechanism involving a phosphatidyl-enzyme intermediate, while the yeast PS synthase catalyzes the reaction with inversion of configuration, which suggests a single-displacement mechanism. Such results lend strong support to the ping-pong mechanism proposed for the E. coli enzyme and the sequential Bi-Bi mechanism proposed for the yeast enzyme, both based on previous isotopic exchange experiments

  17. Attractive Work : Nurses´ work in operating departments, and factors that make it attractive

    OpenAIRE

    Björn, Catrine

    2016-01-01

    Background: Previous studies show that nurse retention is one of the most effective strategies to counteract nursing shortages. Few studies have focused on the crucial resource of registered specialist nurses in operating departments. Aim: The overall aim of this thesis was to gain knowledge on registered specialist nurses’ and assistant nurses’ work in operating departments and on what factors they consider to be important for attractive work. Methods: In Study I, operating room nurses were...

  18. Investment attractiveness of the company : Master thesis for evaluation of the investment attractiveness of Electrolux

    OpenAIRE

    Mazevych, Olena

    2011-01-01

    In order to determine the maximum efficiency of investment solutions, introduced the concept of investment attractiveness of the company. The concept fairly new in economic publications appeared relatively recently and is used primarily in the characterization and evaluation of investment targets, ratings comparisons, and the comparative analysis of processes. Investigation of different points of view on its interpretation revealed that in the current understanding is no uniform approach to t...

  19. The attractiveness of Polish cities for attracting outsourcing and the analysis of benefits for the region

    OpenAIRE

    Kornet, Katarzyna

    2011-01-01

    In western countries outsourcing has been an integral part of many enterprises for a long time. In Poland it is increasingly seen as a part of a long-term development strategy. Although Poland is only beginning to mark its presence in this area, it is quite often listed as one of the countries with a great potential to attract outsourcing. Among the competitive advantages of our country are geographical and cultural proximity to the markets of Western Europe, European Union membership, steady...

  20. Attracting Interest: Dynamic Displays of Proceptivity Increase the Attractiveness of Men and Women

    OpenAIRE

    Clark, AP

    2008-01-01

    Proceptive signals may influence judgments of opposite-sex attractiveness because these signals indicate high mate quality and/or non-threatening behavior but they may also signal high probable rate of return for mating effort. If so, individuals observing these signals may be sensitive to where the signals are directed to; signals directed toward other individuals may not predict what signals would be directed toward the observer. To explore these possibilities I made use of video stimuli co...

  1. Steric effect is a decisive factor on the orientation preference of guest into host: evidence from 5-indanol/β-CD model

    Science.gov (United States)

    Sivakumar, K.; Nichodemus, M.; Sankaran, K. R.

    2014-07-01

    The present study evidences the role of steric effect in the orientation preference of guest into host using the 1:1 inclusion complex of 5-indanol/β-CD model. Two different orientations of guest (5-indanol) into host (β-CD) are considered for the inclusion of 5-indanol into the cavity through the 2° rim of β-CD. The energy differences in the inclusion process are calculated using PM3 semi-empirical method and HF/6-31G** basis set. By the investigation of stabilisation energies, it is found that the energy of both orientations increases to maximum value due to the increase of steric repulsive effect when the crowding of bulky group of 5-indanol occurs at 1° or 2° rim of β-CD. On comparing the fluorescence spectral data of 5-indanol:β-CD complex and 2-napthol:β-CD complex, it is observed that the steric effect is intensified due to the presence of bulky group.

  2. Surface temperature dependence of the steric effect in the scattering of oriented tert-butyl chloride and fluoroform molecules by graphite(0001)

    Science.gov (United States)

    Ionov, Stanislav I.; LaVilla, Michael E.; Mackay, R. Scott; Bernstein, Richard B.

    1990-11-01

    The scattering of focused beams of hexapole-oriented t-BuCl and CHF3 molecules from a graphite (0001) surface has been studied over the surface temperature range 165 < Ts<730 K. The detected number densities of the surface-scattered beams are compared for parallel vs antiparallel incident orientation of the molecular dipole with respect to the surface normal. From the fractional difference in scattered signals, i.e., the so-called steric effect, and from the scattering angular distributions of the unoriented molecules, the relative difference in scattering probabilities for opposite molecular orientations is obtained. For both molecules the magnitude of the relative difference in scattering (the steric effect) increases as Ts decreases. At the lowest surface temperature of 165 K the relative difference in scattering probability reaches +1.5 for t-BuCl (and -0.8 for CHF3), approaching the largest possible magnitude of 2.0, as compared to +0.3 (and -0.4 for CHF3) at the highest temperatures. At all temperatures the steric effect for directly (near-specularly) scattered molecules depends linearly on the degree of molecular orientation. From the angular distribution measurements, it is found that the inelastic translational energy loss in the ``direct'' scattering process increases as Ts decreases. Finally, the temperature dependence of the scattering probability of unoriented beams of t-BuCl and CHF3 has been obtained.

  3. Effects of partner beauty on opposite-sex attractiveness judgments.

    Science.gov (United States)

    Little, Anthony C; Caldwell, Christine A; Jones, Benedict C; DeBruine, Lisa M

    2011-12-01

    Many studies show mate choice copying effects on mate preferences in non-human species in which individuals follow or copy the mate choices of same-sex conspecifics. Recent studies suggest that social learning also influences mate preferences in humans. Studies on heterosexual humans have focused on rating the attractiveness of potential mates (targets) presented alongside individuals of the opposite sex to the target (models). Here, we examined several different types of pairing to examine how specific social learning is to mate preferences. In Study 1, we replicated a previous effect whereby target faces of the opposite sex to the subject were rated as more attractive when paired with attractive than unattractive partner models of the same sex as the subject. Using the same paired stimuli, Study 2 demonstrated no effect of a paired model if subjects were asked to rate targets who were the same sex as themselves. In Study 3, we used pairs of the same sex, stating the pair were friends, and subjects rated targets of the opposite sex to themselves. Attractive models decreased targets' attractiveness, opposite to the effect in Study 1. Finally, Study 4 examined if attractive versus unattractive non-face stimuli might influence attraction. Unlike in Study 1, pairing with attractive stimuli either had no effect or decreased the attractiveness of paired target face images. These data suggest that social transmission of preferences via pairing with attractive/unattractive images is relatively specific to learning about mate preferences but does not influence attractiveness judgments more generally. PMID:21901646

  4. Dimensionality and Transcultural Specificity of the Sexual Attraction Questionnaire (SAQ).

    Science.gov (United States)

    Fernández, Juan; Quiroga, María Angeles; Icaza, Vanessa J; Escorial, Sergio

    2012-03-01

    Sexual attraction was considered a component of sexual orientation from the beginning of the second half of the 20th century to present times. However, some recent researchers have studied sexual attraction as an independent field measuring it by the Sexual Attraction Questionnaire (SAQ). This study analyzes sexual attraction through the SAQ in 400 university students from a Peruvian catholic university. These participants -191 women and 209 men- show a very diverse curricular background. The following hypotheses were tested: a) the structure of the SAQ, pointing out two concepts: attraction to men and attraction to women; b) the high inverse correlation between these two concepts or factors; c) the specific impact of this context in sexual attraction: higher percentage of attracted by none of the sexes and lower percentage of attracted to the opposite sex, in comparison with other contexts; and d) the Lippa prediction (2006, 2007), regarding a higher polarization of sexual attraction for men than for women. Results support the first three hypotheses. Clarifications are laid down with regard to the fourth one. Discussion focuses on theoretical and applied advantages of using the SAQ as opposed to the frequent use of a single item of sexual attraction for each sex. PMID:22379722

  5. Water anomalous thermodynamics, attraction, repulsion, and hydrophobic hydration

    Science.gov (United States)

    Cerdeiriña, Claudio A.; Debenedetti, Pablo G.

    2016-04-01

    A model composed of van der Waals-like and hydrogen bonding contributions that simulates the low-temperature anomalous thermodynamics of pure water while exhibiting a second, liquid-liquid critical point [P. H. Poole et al., Phys. Rev. Lett. 73, 1632 (1994)] is extended to dilute solutions of nonionic species. Critical lines emanating from such second critical point are calculated. While one infers that the smallness of the water molecule may be a relevant factor for those critical lines to move towards experimentally accessible regions, attention is mainly focused on the picture our model draws for the hydration thermodynamics of purely hydrophobic and amphiphilic non-electrolyte solutes. We first focus on differentiating solvation at constant volume from the corresponding isobaric process. Both processes provide the same viewpoint for the low solubility of hydrophobic solutes: it originates from the combination of weak solute-solvent attractive interactions and the specific excluded-volume effects associated with the small molecular size of water. However, a sharp distinction is found when exploring the temperature dependence of hydration phenomena since, in contrast to the situation for the constant-V process, the properties of pure water play a crucial role at isobaric conditions. Specifically, the solubility minimum as well as enthalpy and entropy convergence phenomena, exclusively ascribed to isobaric solvation, are closely related to water's density maximum. Furthermore, the behavior of the partial molecular volume and the partial molecular isobaric heat capacity highlights the interplay between water anomalies, attraction, and repulsion. The overall picture presented here is supported by experimental observations, simulations, and previous theoretical results.

  6. Change in Physical Attraction in Early Romantic Relationships

    Directory of Open Access Journals (Sweden)

    Victor Karandashev

    2014-12-01

    Full Text Available The goal of our research was to study the changes in physical attraction during the early stages of romantic relationships. The longitudinal study explored the personality characteristics of a partner and relationship events affecting physical attraction of early (within the first year romantic relationships. Participants completed an eight-week longitudinal rating of their attraction toward their romantic partner. Factor analysis revealed behavioral, cognitive, emotional, and physiological dimensions. The behavioral and emotional dimensions play the largest role in attraction among both genders, with cognitive dimension also affecting attraction in women. Personality characteristics of one’s partner are significant predictors of physical attraction for both men and women. However, events occurring in the relationship seem to be only reliable predictors for a women’s attraction.

  7. Attraction of semiconductor nanowires: An in situ observation

    International Nuclear Information System (INIS)

    Graphical abstract: -- Abstract: In situ deformation transmission electron microscopy was used to study the attraction behavior of GaAs semiconductor nanowires (NWs). The NWs demonstrated an interesting phenomenon of either head-to-head or body-to-body attraction at distances that depend on the NW diameters. The NWs with a diameter of ∼25 nm attracted at a distance of ∼25 nm, while large-diameter NWs of ∼55 nm showed no obvious attraction. The underlying mechanism governing the attraction of the NWs is proposed and discussed with a mechanistic model. The diameter dependence on the NW attraction behavior is discussed. The finding provides an understanding of the Ampère force in nanostructured materials caused by an electron-beam-induced current while technologically it provides useful hints for designing NW-based devices according to the diameter-dependent attraction behavior of NWs

  8. The dynamical crossover in attractive colloidal systems.

    Science.gov (United States)

    Mallamace, Francesco; Corsaro, Carmelo; Stanley, H Eugene; Mallamace, Domenico; Chen, Sow-Hsin

    2013-12-01

    We study the dynamical arrest in an adhesive hard-sphere colloidal system. We examine a micellar suspension of the Pluronic-L64 surfactant in the temperature (T) and volume fraction (φ) phase diagram. According to mode-coupling theory (MCT), this system is characterized by a cusp-like singularity and two glassy phases: an attractive glass (AG) phase and a repulsive glass (RG) phase. The T - φ phase diagram of this system as confirmed by a previous series of scattering data also exhibits a Percolation Threshold (PT) line, a reentrant behavior (AG-liquid-RG), and a glass-to-glass transition. The AG phase can be generated out of the liquid phase by using T and φ as control parameters. We utilize viscosity and nuclear magnetic resonance (NMR) techniques. NMR data confirm all the characteristic properties of the colloidal system phase diagram and give evidence of the onset of a fractal-like percolating structure at a precise threshold. The MCT scaling laws used to study the shear viscosity as a function of φ and T show in both cases a fragile-to-strong liquid glass-forming dynamic crossover (FSC) located near the percolation threshold where the clustering process is fully developed. These results suggest a larger thermodynamic generality for this phenomenon, which is usually studied only as a function of the temperature. We also find that the critical values of the control parameters, coincident with the PT line, define the locus of the FSC. In the region between the FSC and the glass transition lines the system dynamics are dominated by clustering effects. We thus demonstrate that it is possible, using the conceptual framework provided by extended mode-coupling theory, to describe the way a system approaches dynamic arrest, taking into account both cage and hopping effects. PMID:24320386

  9. The dynamical crossover in attractive colloidal systems

    Energy Technology Data Exchange (ETDEWEB)

    Mallamace, Francesco [Dipartimento di Fisica e Scienze della Terra, Università di Messina and CNISM, I-98168 Messina (Italy); Department of Nuclear Science and Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 (United States); Corsaro, Carmelo [Dipartimento di Fisica e Scienze della Terra, Università di Messina and CNISM, I-98168 Messina (Italy); Stanley, H. Eugene [Center for Polymer Studies and Department of Physics, Boston University, Boston, Massachusetts 02215 (United States); Mallamace, Domenico [Dipartimento di Scienze dell’Ambiente, della Sicurezza, del Territorio, degli Alimenti e della Salute, Università di Messina, I-98166 Messina (Italy); Chen, Sow-Hsin [Department of Nuclear Science and Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 (United States)

    2013-12-07

    We study the dynamical arrest in an adhesive hard-sphere colloidal system. We examine a micellar suspension of the Pluronic-L64 surfactant in the temperature (T) and volume fraction (ϕ) phase diagram. According to mode-coupling theory (MCT), this system is characterized by a cusp-like singularity and two glassy phases: an attractive glass (AG) phase and a repulsive glass (RG) phase. The T − ϕ phase diagram of this system as confirmed by a previous series of scattering data also exhibits a Percolation Threshold (PT) line, a reentrant behavior (AG-liquid-RG), and a glass-to-glass transition. The AG phase can be generated out of the liquid phase by using T and ϕ as control parameters. We utilize viscosity and nuclear magnetic resonance (NMR) techniques. NMR data confirm all the characteristic properties of the colloidal system phase diagram and give evidence of the onset of a fractal-like percolating structure at a precise threshold. The MCT scaling laws used to study the shear viscosity as a function of ϕ and T show in both cases a fragile-to-strong liquid glass-forming dynamic crossover (FSC) located near the percolation threshold where the clustering process is fully developed. These results suggest a larger thermodynamic generality for this phenomenon, which is usually studied only as a function of the temperature. We also find that the critical values of the control parameters, coincident with the PT line, define the locus of the FSC. In the region between the FSC and the glass transition lines the system dynamics are dominated by clustering effects. We thus demonstrate that it is possible, using the conceptual framework provided by extended mode-coupling theory, to describe the way a system approaches dynamic arrest, taking into account both cage and hopping effects.

  10. Dynamic signature for the equilibrium percolation threshold of attractive colloidal fluids

    Science.gov (United States)

    Anekal, Samartha G.; Bahukudumbi, Pradipkumar; Bevan, Michael A.

    2006-02-01

    Short-time self-diffusivities, DSS , are computed for attractive colloidal fluids with van der Waals potentials to identify their percolation threshold and a previously unexplained dynamic transition. Our results show a discontinuous change in the slope of DSS vs temperature as the percolation threshold is crossed. Because DSS depends only on multibody hydrodynamic interactions, the percolation threshold of attractive colloidal fluids is shown to correspond to a transition in a dynamic property consistent with the linear viscoelastic measurements of Woutersen , J. Chem. Phys. 101, 542 (1994).

  11. Exploring the van der Waals Atom-Surface attraction in the nanometric range

    OpenAIRE

    Fichet, Michèle; Dutier, Gabriel; Yarovitski, Alexander; Todorov, Petko; Hamdi, Ismahène; Maurin, Isabelle; Saltiel, Solomon; Sarkisyan, David; Gorza, Marie-Pascale; Bloch, Daniel; Ducloy, Martial

    2007-01-01

    The van der Waals atom-surface attraction, scaling as C3 z-3 for z the atom-surface distance, is expected to be valid in the distance range 1-1000 nm, covering 8-10 orders of magnitudes in the interaction energy. A Cs vapour nanocell allows us to analyze the spectroscopic modifications induced by the atom-surface attraction on the 6P3/2->6D5/2 transition. The measured C3 value is found to be independent of the thickness in the explored range 40-130 nm, and is in agreement with an elementary t...

  12. Retardation turns the van der Waals attraction into Casimir repulsion already at 3 nm

    CERN Document Server

    Boström, Mathias; Brevik, Iver; Ninham, Barry W

    2012-01-01

    Casimir forces between surfaces immersed in bromobenzene have recently been measured by Munday et al. Attractive Casimir forces were found between gold surfaces. The forces were repulsive between gold and silica surfaces. We show the repulsion is due to retardation effects. The van der Waals interaction is attractive at all separations. The retardation driven repulsion sets in already at around 3 nm. To our knowledge retardation effects have never been found at such a small distance before. Retardation effects are usually associated with large distances.

  13. Mating strategies of young women: role of physical attractiveness.

    Science.gov (United States)

    Singh, Devendra

    2004-02-01

    The female physical attractiveness stereotype has been reported to contain both desirable (sociable, poised, interesting) and undesirable (snobbish, likely to request divorce and have extra-marital affairs) personal qualities. To investigate whether such an attractiveness stereotype is cross-cultural, I asked men and women from Azore Island, Guinea-Bissau, Indonesia, and the U.S. to judge the attractiveness of female figures differing in body weight and waist-to-hip ratio (WHR) and to rank these figures according to perceived personal attributes. There was a strong cross-cultural consensus for attractiveness; figures with low WHR were judged to be more attractive than figures with high WHR within each weight category. Participants also judged attractive figures as less faithful than less-attractive figures. To explore the basis of a possible 'darker side ' of the attractiveness stereotype, behavior tactics of young U.S. women were examined. Compared to women with high WHRs, low-WHR women reported engaging in more flirting to make dates jealous, suggesting some truth to the attractiveness stereotype. Taken together, these findings suggest that female attractiveness influences the type of mating strategies employed by women. PMID:15216423

  14. Measuring the operational efficiency of individual theme park attractions.

    Science.gov (United States)

    Kim, Changhee; Kim, Soowook

    2016-01-01

    This study assesses the operation efficiency of theme park attractions using the data envelopment analysis, utilizing actual data on 15 attractions at Samsung Everland located in Yongin-si, Republic of Korea. In particular, this study identifies crowding and waiting time as one of the main causes of visitor's satisfaction, and analyzes the efficiency of individual attractions in terms of waiting time. The installation area, installation cost, and annual repair cost are set as input factors and the number of annual users and customer satisfaction as output factors. The results show that the roller coaster-type attractions were less efficient than other types of attractions while rotating-type attractions were relatively more efficient. However, an importance performance analysis on individual attraction's efficiency and satisfaction showed that operational efficiency should not be the sole consideration in attraction installation. In addition, the projection points for input factors for efficient use of attractions and the appropriate reference set for benchmarking are provided as guideline for attraction efficiency management. PMID:27386283

  15. Probing alkali metal–π interactions with the side chain residue of tryptophan

    OpenAIRE

    Hu, Jiaxin; Barbour, Leonard J.; Gokel, George W.

    2002-01-01

    Feeble forces play a significant role in the organization of proteins. These include hydrogen bonding, hydrophobic interactions, salt bridge formation, and steric interactions. The alkali metal cation-π interaction is a force of potentially profound importance but its consideration in biology has been limited by the lack of experimental evidence. Our previous studies of cation–π interactions with Na+ and K+ involved the side arms of tryptophan (indole), tyrosine (phenol),...

  16. An empirical test of sex differences in the emphasis on physical attractiveness in mate selection.

    Science.gov (United States)

    Colwell, John

    2007-08-01

    Within a context provided by social structural theory, social evolutionary theory, and physical attractiveness stereotyping, the importance of physical attractiveness in heterosexual mate selection was explored by presenting 50 male and 50 female psychology students (M age = 22.5 yr.) during a scheduled class with an opposite sex personals advertisement, wherein the advertiser was described as 'average' or 'good-looking'. Dependent variables consisted of a written paragraph and measures of evaluation (Semantic Differential), attraction, advertisement appeal, and success. An interaction for sex x looks on the qualitative measure showed no effect for men, but the good-looking female advertiser was evaluated more positively. However, for quantitative data, the advertisement was seen as more appealing and likely to be successful when the advertiser was good looking as opposed to average looking, irrespective of sex of advertiser. Findings are discussed in relation to theoretical perspectives. PMID:17918580

  17. Empathy is a beautiful thing: empathy predicts imitation only for attractive others.

    Science.gov (United States)

    Müller, Barbara C N; Van Leeuwen, Matthijs L; Van Baaren, Rick B; Bekkering, Harold; Dijksterhuis, Ap

    2013-10-01

    Research shows that we spontaneously imitate people. Moreover, empathy predicts the degree of this non-conscious imitation. Little is known, however, if or how this expression of empathy is influenced by stable physical characteristics of our interaction-partners. In two studies, we tested whether attractiveness of others moderated the relation between empathy and imitation. While seeing a woman performing joystick movements, participants either imitated, or non-imitated these movements. Results showed that the higher participants empathy score, the faster they imitated an attractive person. The level of empathy did not predict the degree of imitation of unattractive targets. The findings demonstrate that the expression of empathy through imitation can be moderated by attractiveness, thereby introducing a new dimension to the conditionality of empathy. PMID:23786165

  18. Water-Mediated Hydrophobic Interactions.

    Science.gov (United States)

    Ben-Amotz, Dor

    2016-05-27

    Hydrophobic interactions are driven by the combined influence of the direct attraction between oily solutes and an additional water-mediated interaction whose magnitude (and sign) depends sensitively on both solute size and attraction. The resulting delicate balance can lead to a slightly repulsive water-mediated interaction that drives oily molecules apart rather than pushing them together and thus opposes their direct (van der Waals) attraction for each other. As a consequence, competing solute size-dependent crossovers weaken hydrophobic interactions sufficiently that they are only expected to significantly exceed random thermal energy fluctuations for processes that bury more than ∼1 nm(2) of water-exposed area. PMID:27215821

  19. Observation of Attractive and Repulsive Polarons in a Bose-Einstein Condensate

    DEFF Research Database (Denmark)

    Jørgensen, Nils B.; Wacker, Lars; Skalmstang, Kristoffer T.;

    2016-01-01

    The behavior of a mobile impurity particle interacting with a quantum-mechanical medium is of fundamental importance in physics. Due to the great flexibility of atomic gases, our understanding of the impurity problem has improved dramatically since it was realized experimentally in a particularly...... for an impurity interacting with a Bose-Einstein condensate (BEC). We measure the energy of the impurity both for attractive and repulsive interactions with the BEC, and find excellent agreement with theories that incorporate three-body correlations, both in the weak-coupling limits and across unitarity. Our...

  20. Physical attractiveness, happiness, neuroticism, and self-esteem.

    Science.gov (United States)

    Mathes, E W; Kahn, A

    1975-05-01

    The hypotheses that physical attractiveness is positively correlated with happiness, psychological health, and self-esteem was tested with 211 men and women undergraduates. Physical attractiveness was measured by judges' ratings, while happiness, psychological health (neuroticism), and self-esteem were measured by self-report inventories. Physical attractiveness was found to correlate positively with happiness (r equals .37), negatively with neuroticism (r equals minus.22), and positively with self-esteem (r equals .24) for women but not for men (corresponding rs equals .09, .03, and minus.04, respectively). These results were accounted for by the suggestion that physical attractiveness "buys" more for women than for men, and the most prominent outcomes obtained by physical attractiveness--friends and dates--are of greater value to women undergraduates than men. The superior outcomes obtained by the attractive women made them happy, psychologically healthy, and proud of themselves. PMID:1151901