The relationship of female physical attractiveness to body fatness

Directory of Open Access Journals (Sweden)

Guanlin Wang

2015-08-01

Full Text Available Aspects of the female body may be attractive because they signal evolutionary fitness. Greater body fatness might reflect greater potential to survive famines, but individuals carrying larger fat stores may have poor health and lower fertility in non-famine conditions. A mathematical statistical model using epidemiological data linking fatness to fitness traits, predicted a peaked relationship between fatness and attractiveness (maximum at body mass index (BMI = 22.8 to 24.8 depending on ethnicity and assumptions. Participants from three Caucasian populations (Austria, Lithuania and the UK, three Asian populations (China, Iran and Mauritius and four African populations (Kenya, Morocco, Nigeria and Senegal rated attractiveness of a series of female images varying in fatness (BMI and waist to hip ratio (WHR. There was an inverse linear relationship between physical attractiveness and body fatness or BMI in all populations. Lower body fat was more attractive, down to at least BMI = 19. There was no peak in the relationship over the range we studied in any population. WHR was a significant independent but less important factor, which was more important (greater r2 in African populations. Predictions based on the fitness model were not supported. Raters appeared to use body fat percentage (BF% and BMI as markers of age. The covariance of BF% and BMI with age indicates that the role of body fatness alone, as a marker of attractiveness, has been overestimated.

The relationship of female physical attractiveness to body fatness

Science.gov (United States)

Wang, Guanlin; Djafarian, Kurosh; Egedigwe, Chima A.; El Hamdouchi, Asmaa; Ojiambo, Robert; Ramuth, Harris; Wallner-Liebmann, Sandra Johanna; Lackner, Sonja; Diouf, Adama; Sauciuvenaite, Justina; Hambly, Catherine; Vaanholt, Lobke M.; Faries, Mark D.

2015-01-01

Aspects of the female body may be attractive because they signal evolutionary fitness. Greater body fatness might reflect greater potential to survive famines, but individuals carrying larger fat stores may have poor health and lower fertility in non-famine conditions. A mathematical statistical model using epidemiological data linking fatness to fitness traits, predicted a peaked relationship between fatness and attractiveness (maximum at body mass index (BMI) = 22.8 to 24.8 depending on ethnicity and assumptions). Participants from three Caucasian populations (Austria, Lithuania and the UK), three Asian populations (China, Iran and Mauritius) and four African populations (Kenya, Morocco, Nigeria and Senegal) rated attractiveness of a series of female images varying in fatness (BMI) and waist to hip ratio (WHR). There was an inverse linear relationship between physical attractiveness and body fatness or BMI in all populations. Lower body fat was more attractive, down to at least BMI = 19. There was no peak in the relationship over the range we studied in any population. WHR was a significant independent but less important factor, which was more important (greater r2) in African populations. Predictions based on the fitness model were not supported. Raters appeared to use body fat percentage (BF%) and BMI as markers of age. The covariance of BF% and BMI with age indicates that the role of body fatness alone, as a marker of attractiveness, has been overestimated. PMID:26336638

Coherent Destruction of Tunneling of Bosons with Effective Three-Body Interactions

International Nuclear Information System (INIS)

Niu Zhen-Xia; Yu Zi-Fa; Xue Ju-Kui

2015-01-01

The tunneling dynamics of dilute boson gases with three-body interactions in a periodically driven double wells are investigated both theoretically and numerically. In our findings, when the system is with only repulsive two-body interactions or only three-body interactions, the tunneling will be suppressed; while in the case of the coupling between two- and three-body interactions, the tunneling can be either suppressed or enhanced. Particularly, when attractive three-body interactions are twice large as repulsive two-body interactions, CDT occurs at isolated points of driving force, which is similar to the linear case. Considering different interaction, the system can experience different transformation from coherent tunneling to coherent destruction of tunneling (CDT). The quasi-energy of the system as the function of the periodically driving force shows a triangular structure, which provides a deep insight into the tunneling dynamics of the system. (paper)

Three-body forces for electrons by the S-matrix method

International Nuclear Information System (INIS)

Margaritelli, R.

1989-01-01

A electromagnetic three-body potential between eletrons is derived by the S-matrix method. This potential can be compared up to a certain point with other electromagnetic potentials (obtained by other methods) encountered in the literature. However, since the potential derived here is far more complete than others, this turns direct comparison with the potentials found in the literature somewhat difficult. These calculations allow a better understanding of the S-matrix method as applied to problems which involve the calculations of three-body nuclear forces (these calculations are performed in order to understand the 3 He form factor). Furthermore, these results enable us to decide between two discrepant works which derive the two-pion exchange three-body potential, both by the S-matrix method. (author) [pt

Three-body correlations and conditional forces in suspensions of active hard disks

Science.gov (United States)

Härtel, Andreas; Richard, David; Speck, Thomas

2018-01-01

Self-propelled Brownian particles show rich out-of-equilibrium physics, for instance, the motility-induced phase separation (MIPS). While decades of studying the structure of liquids have established a deep understanding of passive systems, not much is known about correlations in active suspensions. In this work we derive an approximate analytic theory for three-body correlations and forces in systems of active Brownian disks starting from the many-body Smoluchowski equation. We use our theory to predict the conditional forces that act on a tagged particle and their dependence on the propulsion speed of self-propelled disks. We identify preferred directions of these forces in relation to the direction of propulsion and the positions of the surrounding particles. We further relate our theory to the effective swimming speed of the active disks, which is relevant for the physics of MIPS. To test and validate our theory, we additionally run particle-resolved computer simulations, for which we explicitly calculate the three-body forces. In this context, we discuss the modeling of active Brownian swimmers with nearly hard interaction potentials. We find very good agreement between our simulations and numerical solutions of our theory, especially for the nonequilibrium pair-distribution function. For our analytical results, we carefully discuss their range of validity in the context of the different levels of approximation we applied. This discussion allows us to study the individual contribution of particles to three-body forces and to the emerging structure. Thus, our work sheds light on the collective behavior, provides the basis for further studies of correlations in active suspensions, and makes a step towards an emerging liquid state theory.

Effect of Leg-to-Body Ratio on Body Shape Attractiveness.

Science.gov (United States)

Kiire, Satoru

2016-05-01

Recent studies have examined various aspects of human physical attractiveness. Attractiveness is considered an evolved psychological mechanism acquired via natural selection because an attractive body reflects an individual's health and fertility. The length of the legs is an often-emphasized aspect of attractiveness and has been investigated using the leg-to-body ratio (LBR), which reflects nutritional status of the infant, health status, fecundity, and other factors that are predictive of physical fitness. However, previous studies of leg length and physical fitness have produced mixed results. The present study investigated the relationship between LBR, defined as the height to perineum divided by total height, and perceived attractiveness. Three-dimensional stimuli (11 male and 11 female) were constructed with various LBR features. Each stimulus was rated by 40 women and 40 men in Japan on a 7-point scale. The results showed that the values closest to the average LBRs were rated as the most attractive. Furthermore, by fitting a quadratic curve on the relationship between attractiveness and LBR, an inverted U-shaped curve with the peak located at the average LBR was observed. In addition, high LBR values were rated as more attractive in females, whereas the opposite was true for males. These results suggest that average LBR is indicative of good health and good reproductive potential, whereas more extreme values are avoided because they could be indicative of diseases and other maladaptive conditions.

Effects of solute--solvent attractive forces on hydrophobic correlations

International Nuclear Information System (INIS)

Pratt, L.R.; Chandler, D.

1980-01-01

A theory is presented for the effect of slowly varying attractive forces on correlations between nonpolar solutes in dilute aqueous solution. We find that hydrophobic correlations are sensitive to relatively long range slowly varying interactions. Thus, it is possible to make qualitative changes in these correlations by introducing small changes in the attractive forces. Several model calculations are presented to illustrate these facts. The contributions of the Lennard-Jones attractive forces to the computer simulation results of Pangali, Rao, and Berne are calculated. For this case it is found that the potential of mean force between spherical nonpolar solutes is hardly affected by inclusion of attractive forces. However, the osmotic second virial coefficient is dominated by the contributions of the attractive forces. For spherical solutes which provide a reasonable model for the methane molecule, inclusion of attractive forces produces a qualitative change in the methane--methane potential of mean force. The connection between these effects of slowly varying attractive forces and the enthalpic part of Ben-Naim's deltaA/sup H/I is discussed

The Tucson-Melbourne Three-Body Force in a Translationally-Invariant Harmonic Oscillator Basis

Science.gov (United States)

Marsden, David; Navratil, Petr; Barrett, Bruce

2000-09-01

A translationally-invariant three-body basis set has been employed in shell model calculations on ^3H and ^3He including the Tucson-Melbourne form of the real nuclear three-body force. The basis consists of harmonic oscillators in Jacobi coordinates, explicitly avoiding the centre of mass drift problem in the calculations. The derivation of the three-body matrix elements and the results of large basis effective interaction shell model calculations will be presented. J. L. Friar, B. F. Gibson, G. L. Payne and S. A. Coon; Few Body Systems 5, 13 (1988) P. Navratil, G.P. Kamuntavicius and B.R. Barrett; Phys. Rev. C. 61, 044001 (2000)

Three-nucleon forces

International Nuclear Information System (INIS)

Sauer, P.U.

2014-01-01

In this paper, the role of three-nucleon forces in ab initio calculations of nuclear systems is investigated. The difference between genuine and induced many-nucleon forces is emphasized. Induced forces arise in the process of solving the nuclear many-body problem as technical intermediaries toward calculationally converged results. Genuine forces make up the Hamiltonian. They represent the chosen underlying dynamics. The hierarchy of contributions arising from genuine two-, three- and many-nucleon forces is discussed. Signals for the need of the inclusion of genuine three-nucleon forces are studied in nuclear systems, technically best under control, especially in three-nucleon and four-nucleon systems. Genuine three-nucleon forces are important for details in the description of some observables. Their contributions to observables are small on the scale set by two-nucleon forces. (author)

Role of three-body forces in lattice dynamics of neodymium antimonide

International Nuclear Information System (INIS)

Gupta, H.N.; Kanti Chandra

1979-01-01

Recently the experimental phonon-dispersion curves of neodymium antimonide (NdSb) have been reported by Wakabayashi and Furrer (1976). These results have been analysed using an extended three-body force shell model (ESTM) in its nearest-neighbour version which provides a very good agreement for acoustic- and a reasonably good agreement for optical-branches of dispersion curves. This shows clearly the effect of three-body forces in this solid. The lack in degree of agreement in the optical branches may be ascribed to the presence of (i) zero Lyddane-Sachs-Teller (LST) splitting of zone-centre optical vibration frequencies (ωsub(Lo) and ωsub(To)) (ii) some anomalous wiggles in those branches. While the former is explained by setting Lundquist's effective charge parameter (esub(L)) equal to zero in the theory of ESTM, the later is expected to be explained satisfactorily by including free-electron screening effects in the theoretical framework of ESTM. (auth.)

The Body and the Beautiful: Health, Attractiveness and Body Composition in Men's and Women's Bodies.

Directory of Open Access Journals (Sweden)

Mary-Ellen Brierley

Full Text Available The dominant evolutionary theory of physical attraction posits that attractiveness reflects physiological health, and attraction is a mechanism for identifying a healthy mate. Previous studies have found that perceptions of the healthiest body mass index (weight scaled for height; BMI for women are close to healthy BMI guidelines, while the most attractive BMI is significantly lower, possibly pointing to an influence of sociocultural factors in determining attractive BMI. However, less is known about ideal body size for men. Further, research has not addressed the role of body fat and muscle, which have distinct relationships with health and are conflated in BMI, in determining perceived health and attractiveness. Here, we hypothesised that, if attractiveness reflects physiological health, the most attractive and healthy appearing body composition should be in line with physiologically healthy body composition. Thirty female and 33 male observers were instructed to manipulate 15 female and 15 male body images in terms of their fat and muscle to optimise perceived health and, separately, attractiveness. Observers were unaware that they were manipulating the muscle and fat content of bodies. The most attractive apparent fat mass for female bodies was significantly lower than the healthiest appearing fat mass (and was lower than the physiologically healthy range, with no significant difference for muscle mass. The optimal fat and muscle mass for men's bodies was in line with the healthy range. Male observers preferred a significantly lower overall male body mass than did female observers. While the body fat and muscle associated with healthy and attractive appearance is broadly in line with physiologically healthy values, deviations from this pattern suggest that future research should examine a possible role for internalization of body ideals in influencing perceptions of attractive body composition, particularly in women.

The Body and the Beautiful: Health, Attractiveness and Body Composition in Men's and Women's Bodies.

Science.gov (United States)

Brierley, Mary-Ellen; Brooks, Kevin R; Mond, Jonathan; Stevenson, Richard J; Stephen, Ian D

2016-01-01

The dominant evolutionary theory of physical attraction posits that attractiveness reflects physiological health, and attraction is a mechanism for identifying a healthy mate. Previous studies have found that perceptions of the healthiest body mass index (weight scaled for height; BMI) for women are close to healthy BMI guidelines, while the most attractive BMI is significantly lower, possibly pointing to an influence of sociocultural factors in determining attractive BMI. However, less is known about ideal body size for men. Further, research has not addressed the role of body fat and muscle, which have distinct relationships with health and are conflated in BMI, in determining perceived health and attractiveness. Here, we hypothesised that, if attractiveness reflects physiological health, the most attractive and healthy appearing body composition should be in line with physiologically healthy body composition. Thirty female and 33 male observers were instructed to manipulate 15 female and 15 male body images in terms of their fat and muscle to optimise perceived health and, separately, attractiveness. Observers were unaware that they were manipulating the muscle and fat content of bodies. The most attractive apparent fat mass for female bodies was significantly lower than the healthiest appearing fat mass (and was lower than the physiologically healthy range), with no significant difference for muscle mass. The optimal fat and muscle mass for men's bodies was in line with the healthy range. Male observers preferred a significantly lower overall male body mass than did female observers. While the body fat and muscle associated with healthy and attractive appearance is broadly in line with physiologically healthy values, deviations from this pattern suggest that future research should examine a possible role for internalization of body ideals in influencing perceptions of attractive body composition, particularly in women.

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

International Nuclear Information System (INIS)

Hussein, M.S.; Vorov, O.K.

2002-01-01

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 δ 2 (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 ∫d 2 r-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

The three-body forces with two δ excitation and N+d scattering

International Nuclear Information System (INIS)

Uzu, Eizo; Koike, Yasuro; Yamaguchi, Masahiro; Kamada, Hiroyuki

2005-01-01

The differential cross section of 250 MeV N+d scattering was different from the results of Faddeev calculation. The possibility of δ excitation of two nucleons of deuteron in the initial state is considered and the degree of freedom of δδ excitation is applied to improve the three-body force effects. The system consisted of two nucleons, nucleon and δ particle, and two δparticles is called by NN, Nδ and δδ system, respectively. The first calculation was carried out by using AV14 potential as ordinary nuclear force and AV28 as interaction with Nδ and δδ as three-body. The results of calculation for 250 and 135 MeV N+d scattering showed no effect on the differential cross section but the large effect on the tensor resolving power. (S.Y.)

Attractiveness of the female body: Preference for the average or the supernormal?

Directory of Open Access Journals (Sweden)

Marković Slobodan

2017-01-01

Full Text Available The main purpose of the present study was to contrast the two hypotheses of female body attractiveness. The first is the “preference-for-the average” hypothesis: the most attractive female body is the one that represents the average body proportions for a given population. The second is the “preference-for-the supernormal” hypothesis: according to the so-called “peak shift effect”, the most attractive female body is more feminine than the average. We investigated the preference for three female body characteristics: waist to hip ratio (WHR, buttocks and breasts. There were 456 participants of both genders. Using a program for computer animation (DAZ 3D three sets of stimuli were generated (WHR, buttocks and breasts. Each set included six stimuli ranked from the lowest to the highest femininity level. Participants were asked to choose the stimulus within each set which they found most attractive (task 1 and average (task 2. One group of participants judged the body parts that were presented in the global context (whole body, while the other group judged the stimuli in the local context (isolated body parts only. Analyses have shown that the most attractive WHR, buttocks and breasts are more feminine (meaning smaller for WHR and larger for breasts and buttocks than average ones, for both genders and in both presentation contexts. The effect of gender was obtained only for the most attractive breasts: males prefer larger breasts than females. Finally, most attractive and average WHR and breasts were less feminine in the local than in the global context. These results support the preference-for the supernormal hypothesis: all analyses have shown that both male and female participants preferred female body parts which are more feminine than those judged average. [Project of the Serbian Ministry of Education, Science and Technological Development, Grant no. 179033

Nine-Month-Old Infants Prefer Unattractive Bodies over Attractive Bodies

Science.gov (United States)

Heron-Delaney, Michelle; Quinn, Paul C.; Lee, Kang; Slater, Alan M.; Pascalis, Olivier

2013-01-01

Infant responses to adult-defined unattractive male body shapes versus attractive male body shapes were assessed using visual preference and habituation procedures. Looking behavior indicated that 9-month-olds have a preference for unattractive male body shapes over attractive ones; however, this preference is demonstrated only when head…

Three-body forces in p-shell nuclei

International Nuclear Information System (INIS)

Hees, A.G.M. van; Booten, J.G.L.; Glaudemans, P.W.M.

1990-01-01

Within the (0 + 1)ℎω shell-model space for p-shell nuclei we found that a schematic three-body interaction in addition to a translationally invariant two-body interaction leads to a strongly improved description of energy levels. The present three-body interaction is related to the Δ-isobar intermediate-state model of the two-pion exchange three-nucleon interaction. (orig.)

Body Image, Physical Attractiveness, and Depression.

Science.gov (United States)

Noles, Steven W.; And Others

1985-01-01

Examined the relationship between body image, global self-concept, and depression. Men and women (N=224) completed questionnaires and were videotaped and objectively rated on attractiveness. Results indicated that depressed subjects were less satisfied with their bodies and saw themselves as less physically attractive than was reported by…

Attractive forces study in macromolecules and critical systems; Etude des forces attractives dans les macromolecules et les systemes critiques

Energy Technology Data Exchange (ETDEWEB)

Penninckx-Sans, A.

1995-07-10

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.

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...

The three-body problem

International Nuclear Information System (INIS)

Musielak, Z E; Quarles, B

2014-01-01

The three-body problem, which describes three masses interacting through Newtonian gravity without any restrictions imposed on the initial positions and velocities of these masses, has attracted the attention of many scientists for more than 300 years. In this paper, we present a review of the three-body problem in the context of both historical and modern developments. We describe the general and restricted (circular and elliptic) three-body problems, different analytical and numerical methods of finding solutions, methods for performing stability analysis and searching for periodic orbits and resonances. We apply the results to some interesting problems of celestial mechanics. We also provide a brief presentation of the general and restricted relativistic three-body problems, and discuss their astronomical applications. (review article)

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.

Effect of three-body forces on the lattice dynamics of noble metals

Indian Academy of Sciences (India)

A simple method to generate an effective electron–ion interaction pseudopotential from the energy wave number characteristic obtained by first principles calculations has been suggested. This effective potential has been used, in third order perturbation, to study the effect of three-body forces on the lattice dynamics of ...

Coulomb effects in deuteron stripping reactions as a three-body problem

International Nuclear Information System (INIS)

Osman, A.

1981-08-01

Deuteron stripping nuclear reactions are reconsidered as a three-body problem. The Coulomb effects between the proton and the target nucleus are investigated. The mathematical formalism introduces three-body integral equations which can be exactly calculated for such simple models. These coupled integral equations suitably include the Coulomb effects due to replusive or attractive Coulomb potential. Numerical calculations of the differential cross-sections of the reactions 28 Si(d,p) 29 Si and 40 Ca(d,p) 41 Ca are carried out showing the importance of the Coulomb effects. The angular distributions of these reactions are theoretically calculated and fitted to the experimental data. From this fitting, reasonable spectroscopic factors are obtained. Inclusion of Coulomb force in the three-body model are found to improve the results by a percentage of about 6.826%. (author)

On contribution of three-body forces to Nd interaction at intermediate energies

International Nuclear Information System (INIS)

Uzikov, Yu.N.

2001-01-01

Available data on large-angle nucleon-deuteron elastic scattering Nd → dN below the pion threshold give a signal for three-body forces. There is a problem of separation of possible subtle aspects of these forces from off-shell effects in two-nucleon potentials. By considering the main mechanisms of the process Nd → dN, we show qualitatively that in the quasi-binary reaction N + d → (NN) + N with the final spin singlet NN-pair in the S-state the relative contribution of the 3N forces differs substantially from the elastic channel. It gives a new testing ground for the problem in question

A microscopic approach to Casimir and Casimir–Polder forces between metallic bodies

International Nuclear Information System (INIS)

Barcellona, Pablo; Passante, Roberto

2015-01-01

We consider the Casimir–Polder interaction energy between a metallic nanoparticle and a metallic plate, as well as the Casimir interaction energy between two macroscopic metal plates, in terms of the many-body dispersion interactions between their constituents. Expressions for two- and three-body dispersion interactions between the microscopic parts of a real metal are first obtained, both in the retarded and non-retarded limits. These expressions are then used to evaluate the overall two- and three-body contributions to the macroscopic Casimir–Polder and Casimir force, and to compare them with each other, for the two following geometries: metal nanoparticle/half-space and half-space/half-space, where all the materials are assumed perfect conductors. The above evaluation is obtained by summing up the contributions from the microscopic constituents of the bodies (metal nanoparticles). In the case of nanoparticle/half-space, our results fully agree with those that can be extracted from the corresponding macroscopic results, and explicitly show the non-applicability of the pairwise approximation for the geometry considered. In both cases, we find that, while the overall two-body contribution yields an attractive force, the overall three-body contribution is repulsive. Also, they turn out to be of the same order, consistently with the known non applicability of the pairwise approximation. The issue of the rapidity of convergence of the many-body expansion is also briefly discussed

Study on 16O in the alpha particle model using three-body forces

International Nuclear Information System (INIS)

Agrello, D.A.

1979-01-01

A study of the ground state of 16 O is made using an alpha particle model, all without internal structure, interacting through two-and three-body forces. Some nuclear properties of 16 O, such as binding energy and gaps, are also studied. (L.C.) [pt

Many-body forces in nuclear shell-model

International Nuclear Information System (INIS)

Rath, P.K.

1985-01-01

In the microscopic derivation of the effective Hamiltonian for the nuclear shell model many-body forces between the valence nucleons occur. These many-body forces can be discriminated in ''real'' many-body forces, which can be related to mesonic and internal degrees of freedom of the nucleons, and ''effective'' many-body forces, which arise by the confinement of the nucleonic Hilbert space to the finite-dimension shell-model space. In the present thesis the influences of such three-body forces on the spectra of sd-shell nuclei are studied. For this the two common techniques for shell-model calculations (Oak Ridge-Rochester and Glasgow representation) are extended in such way that a general three-body term in the Hamiltonian can be regarded. The studies show that the repulsive contributions of the considered three-nucleon forces become more important with increasing number of valence nucleons. By this the particle-number dependence of empirical two-nucleon forces can be qualitatively explained. A special kind of effective many-body force occurs in the folded diagram expansion of the energy-dependent effective Hamiltonian for the shell model. Thereby it is shown that the contributions of the folded diagrams with three nucleons are just as important as those with two nucleons. Thus it is to be suspected that the folded diagram expansion contains many-particle terms with arbitrary particle number. The present studies however show that four nucleon effects are neglegible so that the folded diagram expansion can be confined to two- and three-particle terms. In shell-model calculations which extend over several main shells the influences of the spurious center-of-mass motion must be regarded. A procedure is discussed by which these spurious degrees of freedom can be exactly separated. (orig.) [de

Attractive and repulsive quantum forces from dimensionality of space

DEFF Research Database (Denmark)

Bialynicki-Birula, I.; Cirone, M.A.; Dahl, Jens Peder

2002-01-01

Two particles of identical mass attract and repel each other even when there exist no classical external forces and their average relative momentum vanishes. This quantum force depends crucially on the number of dimensions of space.......Two particles of identical mass attract and repel each other even when there exist no classical external forces and their average relative momentum vanishes. This quantum force depends crucially on the number of dimensions of space....

Shukla-Eliasson attractive force: Revisited

Science.gov (United States)

Akbari-Moghanjoughi, M.; Akbari-Moghanjoughi

2013-04-01

By investigating the dielectric response of the Fermi-Dirac plasma in the linear limit and evaluating 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 are strongly sensitive to the variation of plasma density and composition. Current research can also have applications in the study of strong laser-matter interactions and inertially confined plasmas.

Studies of the nuclear three-body system with three dimensional Faddeev calculations

Science.gov (United States)

Liu, Hang

A three-body system consists of either a bound state of three particles with definite binding energy or a beam of single particles scattered from a target, where two of the particles are bound. Of the particles are nucleons, the interactions between them are strong and short ranged. A theoretical framework for studying the dynamics of a nuclear three-body system is the Faddeev scheme. In this work the equation for three-body scattering and the bound state are formulated in momentum space, and directly solved in terms of vector variables. For three identical bosons the Faddeev equation for scattering is a three- dimensional inhomogeneous integral equation in five variables, and is solved by Padé summation. The equation for the bound state is a homogeneous one in three variables, and is solved by a Lanczos' type method. The corresponding algorithms are presented, and their numerical feasibility is demonstrated. Elastic as well as inelastic scattering processes in the intermediate energy regime up to 1 GeV incident energy are studied for the first within a Faddeev scheme. The two-body force employed is of Malfliet-Tjon type. Specific emphasis is placed on studying the convergence of the multiple scattering series given by the Faddeev equations. For the bound state, a three-body force of Fujita- Miyazawa type is incorporated in addition to the two-body force. The effects of this three-body force on the bound state properties are investigated.

Relativistic origin of three-nucleon force

International Nuclear Information System (INIS)

Haberzettl, H.; Parke, W.C.

1995-01-01

Based on the manifestly covariant cluster-dynamical formalism recently proposed by Haberzettl, the three-body forces entering three-nucleon equations are discussed. It is shown that there exist additional contributions to the (nonrelativistic) three-body force, not taken into account in the usual treatments, arising from the proper nonrelativistic limits of higher-order meson-exchange Feynman diagrams. Using the Paris potential, a five-channel triton bound-state calculation results in additional binding of about 0.6 MeV due to this new mechanism. copyright 1995 American Institute of Physics

The baryonic spectrum in a constituent quark model including a three-body force

International Nuclear Information System (INIS)

Desplanques, B.; Gignoux, C.; Silvestre-Brac, B.; Gonzalez, P.; Navarro, J.; Noguera, S.

1992-01-01

We analyze, within a non-relativistic quark model, the low energy part of the baryonic spectrum in the octet and decuplet flavour representations. The relevance of a strong Coulomb potential is emphasized in order to explain its general features. The addition of a three-body force allows to solve the 'Roper puzzle', giving a consistent explanation to its relative position in the spectrum. (orig.)

Derivation of a pion-rho exchange three-body force and application to the trinucleon system

International Nuclear Information System (INIS)

Robillota, M.R.; Isidro Filho, M.P.

1982-12-01

The pion-rho exchange three-body force is derived by means of Lagrangians which are approximately invariant under chiral and gauge transformations. The leading contribution to the potential arises from a seagull diagram, which corresponds to forces that are dominantly repulsive and comparable to those due to the exchange of two pions. The qualitative features of the results are analysed by means of plots of the energy of the trinucleon system. (Author) [pt

Derivation of a pion-RHO exchange three-body force and application to the trinucleon system

International Nuclear Information System (INIS)

Robilotta, M.R.; Isidro Filho, M.P.

1984-01-01

The pion-rho exchange three-body force is derived by means of lagrangians which are approximately invariant under chiral and gauge transformations. The leading contribution to the potential arises from a seagull diagram, which corresponds to forces that are dominantly repulsive and comparable to those due to the exchange of two pions. The qualitative features of our results are analysed by means of plots of the energy of the trinucleon system. (orig.)

Attractive non-DLVO forces induced by adsorption of monovalent organic ions.

Science.gov (United States)

Smith, Alexander M; Maroni, Plinio; Borkovec, Michal

2017-12-20

Direct force measurements between negatively charged colloidal particles were carried out using an atomic force microscope (AFM) in aqueous solutions containing monovalent organic cations, namely tetraphenylarsonium (Ph 4 As + ), 1-hexyl-3-methylimidazolium (HMIM + ), and 1-octyl-3-methylimidazolium (OMIM + ). These ions adsorb to the particle surface, and induce a charge reversal. The forces become attractive at the charge neutralization point, but they are stronger than van der Waals forces. This additional and unexpected attraction decays exponentially with a decay length of a few nanometers, and is strikingly similar to the one previously observed in the presence of multivalent ions. This attractive force probably originates from coupled spontaneous charge fluctuations on the respective surfaces as initially suggested by Kirkwood and Shumaker.

Scalar meson field and many-body forces. Chapter 23

International Nuclear Information System (INIS)

Nyman, E.M.

1979-01-01

In applications of field theory to the theory of the nuclear forces, one has frequently assumed that there is a scalar meson. It will then be responsible for most of the medium-range attraction between the nucleons. According to current ideas, however, it is possible to account for the medium-range attraction without an elementary sigma meson. This approach requires a careful treatment of the exchange of interacting pairs of π mesons, such as to include those ππ interactions which are responsible for the formation and decay of the sigma meson. Recently, the scalar field in the nuclear many-body problem has begun to receive more attention. There are two reasons for this change of philosophy. One reason is the discovery of neutron stars. In neutron stars, the nucleon number density can be much higher than in nuclei. One therefore wants to derive the equation of state from a relativistic many-body theory. This forces one to deal explicitly with a set of mesons, such that in the non-relativistic limit one recovers the one-boson-exchange potential. (Auth.)

The effect of including tensor forces in nucleon-nucleon interaction on three-nucleon binding energy

International Nuclear Information System (INIS)

Osman, A.; Ramadan, S.

1986-01-01

Separable two-body interactions are used in considering the three-nucleon problem. The nucleon-nucleon potentials are taken to include attraction and repulsion as well as tensor forces. The separable approximation is used in order to investigate the effect of the tensor forces. The separable expansion is introduced in the three-nucleon problem, by which the Faddeev equations are reduced to a well-behaved set of coupled integral equations. Numerical calculations are carried out for the obtained integral equations using potential functions of the Yamaguchi, Gaussian, Takabin, Mongan and Reid forms. The present calculated values of the binding energies of the 3 H and 3 He nuclei are in good agreement with the experimental values. The effect of including the tensor forces in the nucleon-nucleon interactions is found to improve the three-nucleon binding energy by about 4.490% to 8.324%. 37 refs., 2 tabs. (author)

The similarity of attractive and repulsive forces on a lattice

Science.gov (United States)

Mirahmadi, Marjan-S.; Fatollahi, Amir H.; Khorrami, Mohammad

2015-07-01

On a lattice, as the momentum space is compact, the kinetic energy is bounded not only from below but also from above. It is shown that this somehow removes the distinction between repulsive and attractive forces. In particular, it is seen that a region with attractive force would appear forbidden for states with energies higher than a certain value, while repulsive forces could develop bound-states. An explicit transformation is introduced which transforms the spectrum of a system corresponding to a repulsive force, to that of a similar system corresponding to an attractive force. Explicit numerical examples are presented for discrete energies of bound-states of a particle experiencing repulsive force by a piecewise constant potential. Finally, the parameters of a specific one-dimensional (1D) translationally invariant system on continuum are tuned so that the energy of the system resembles the kinetic energy of a system on a 1D lattice. In particular, the parameters are tuned so that while the width of the first energy band and its position are kept finite, the gap between the first energy band and the next energy band goes to infinity, so that effectively only the first energy band is relevant.

The Relations among Body Image, Physical Attractiveness, and Body Mass in Adolescence.

Science.gov (United States)

Rosenblum, Gianine D.; Lewis, Michael

1999-01-01

Examined body dissatisfaction, physical attractiveness, and body mass index in adolescents at 13, 15, and 18 years of age. Found that sex differences in body dissatisfaction emerged between 13 and 15 years and were maintained. Girls' body dissatisfaction increased, whereas boys' decreased. Body dissatisfaction was weakly related to others' rating…

Classical description of dynamical many-body systems with central forces, spin-orbit forces and spin-spin forces

International Nuclear Information System (INIS)

Goepfert, A.

1994-01-01

This thesis develops a new model, and related numerical methods, to describe classical time-dependent many-body systems interacting through central forces, spin-orbit forces and spin-spin forces. The model is based on two-particle interactions. The two-body forces consist of attractive and repulsive parts. In this model the investigated multi-particle systems are self-bound. Also the total potential of the whole ensemble is derived from the two-particle potential and is not imposed 'from outside'. Each particle has the three degrees of freedom of its centre-of-mass motion and the spin degree of freedom. The model allows for the particles to be either charged or uncharged. Furthermore, each particle has an angular momentum, an intrinsic spin, and a magnetic dipole moment. Through the electromagnetic forces between these charges and moments there arise dynamical couplings between them. The internal interactions between the charges and moments are well described by electromagnetic coupling mechanisms. In fact, compared to conventional classical molecular dynamics calculations in van der Waals clusters, which have no spin degrees of freedom, or for Heisenberg spin Systems, which have no orbital degrees of freedom, the model presented here contains both types of degrees of freedom with a highly non-trivial coupling. The model allows to study the fundamental effects resulting from the dynamical coupling of the spin and the orbital-motion sub-systems. In particular, the dynamics of the particle mass points show a behaviour basically different from the one of particles in a potential with only central forces. Furthermore, a special type of quenching procedure was invented, which tends to drive the multi-particle Systems into states with highly periodic, non-ergodic behaviour. Application of the model to cluster simulations has provided evidence that the model can also be used to investigate items like solid-to-liquid phase transitions (melting), isomerism and specific heat

Role of attractive forces in determining the equilibrium structure and dynamics of simple liquids

DEFF Research Database (Denmark)

Toxværd, Søren

2015-01-01

Molecular Dynamics simulations of a Lennard-Jones system with different range of attraction show that the attractive forces modify the radial distribution of the particles. For condensed liquids only, the forces within the the first coordination shell (FCS) are important, but for gases and moderate...... condensed fluids, even the attractive forces outside the FCS play a role. The changes in the distribution caused by neglecting the attractive forces, lead to a too high pressure. The weak long-range attractions damp the dynamics and the diffusion of the particles in gas-, super critical fluid- and in liquid...

Precise numerical results for limit cycles in the quantum three-body problem

International Nuclear Information System (INIS)

Mohr, R.F.; Furnstahl, R.J.; Hammer, H.-W.; Perry, R.J.; Wilson, K.G.

2006-01-01

The study of the three-body problem with short-range attractive two-body forces has a rich history going back to the 1930s. Recent applications of effective field theory methods to atomic and nuclear physics have produced a much improved understanding of this problem, and we elucidate some of the issues using renormalization group ideas applied to precise nonperturbative calculations. These calculations provide 11-12 digits of precision for the binding energies in the infinite cutoff limit. The method starts with this limit as an approximation to an effective theory and allows cutoff dependence to be systematically computed as an expansion in powers of inverse cutoffs and logarithms of the cutoff. Renormalization of three-body bound states requires a short range three-body interaction, with a coupling that is governed by a precisely mapped limit cycle of the renormalization group. Additional three-body irrelevant interactions must be determined to control subleading dependence on the cutoff and this control is essential for an effective field theory since the continuum limit is not likely to match physical systems (e.g., few-nucleon bound and scattering states at low energy). Leading order calculations precise to 11-12 digits allow clear identification of subleading corrections, but these corrections have not been computed

Women's meta-perceptions of attractiveness and their relations to body image.

Science.gov (United States)

Dijkstra, Pieternel; Barelds, Dick P H

2011-01-01

The present study examined meta-perceptions of attractiveness among women. More specifically, ratings were collected about how women thought their partner, family and friends, and strangers would view their physical attractiveness. In an online survey, 1287 Dutch women (aged 19-80 years) answered questions concerning meta-perceptions of attractiveness, demographic data, body mass index (BMI), body image (Body Areas Satisfaction Scale, self-rated general physical attractiveness, and actual-ideal weight discrepancy), and self-esteem. Results showed that women's meta-perceptions of attractiveness reflected the level of closeness of the relationship with the other person, with the most positive meta-perceptions reported for the partner, followed by those for family and friends, and the least positive meta-perceptions for strangers. Meta-perceptions were strongly related to body image, self-esteem and BMI. Self-ratings of attractiveness appeared to be lower than all meta-perceptions of attractiveness, suggesting that women are aware of their own negative self-bias and/or other people's positive bias. Copyright © 2010 Elsevier Ltd. All rights reserved.

The effect of magnet size on the levitation force and attractive force of single-domain YBCO bulk superconductors

International Nuclear Information System (INIS)

Yang, W M; Chao, X X; Bian, X B; Liu, P; Feng, Y; Zhang, P X; Zhou, L

2003-01-01

The levitation forces between a single-domain YBCO bulk and several magnets of different sizes have been measured at 77 K to investigate the effect of the magnet size on the levitation force. It is found that the levitation force reaches a largest (peak) value when the size of the magnet approaches that of the superconductor when the other conditions are fixed. The absolute maximum attractive force (in the field-cooled state) increases with the increasing of the magnet size, and is saturated when the magnet size approaches that of the superconductor. The maximum attractive force in the field-cooled (FC) state is much higher than that of the maximum attractive force in the zero field-cooled (ZFC) state. The results indicate that the effects of magnetic field distribution on the levitation force have to be considered during the designing and manufacturing of superconducting devices

Three-nucleon forces and the trinucleon bound states

International Nuclear Information System (INIS)

Friar, J.L.; Frois, B.

1986-04-01

A summary of the bound-state working group session of the ''International Symposium on the Three-Body Force in the Three-Nucleon System'' is presented. The experimental evidence for three-nucleon forces has centered on two ground state properties: the tritium binding energy and the trinucleon form factors. Both are discussed

The effect of meat consumption on body odor attractiveness.

Science.gov (United States)

Havlicek, Jan; Lenochova, Pavlina

2006-10-01

Axillary body odor is individually specific and potentially a rich source of information about its producer. Odor individuality partly results from genetic individuality, but the influence of ecological factors such as eating habits are another main source of odor variability. However, we know very little about how particular dietary components shape our body odor. Here we tested the effect of red meat consumption on body odor attractiveness. We used a balanced within-subject experimental design. Seventeen male odor donors were on "meat" or "nonmeat" diet for 2 weeks wearing axillary pads to collect body odor during the final 24 h of the diet. Fresh odor samples were assessed for their pleasantness, attractiveness, masculinity, and intensity by 30 women not using hormonal contraceptives. We repeated the same procedure a month later with the same odor donors, each on the opposite diet than before. Results of repeated measures analysis of variance showed that the odor of donors when on the nonmeat diet was judged as significantly more attractive, more pleasant, and less intense. This suggests that red meat consumption has a negative impact on perceived body odor hedonicity.

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.

[Sexual attraction: a concept analysis using an evolutionary perspective].

Science.gov (United States)

Yang, Shu-Chin; Chu, Chun-Hong; Lu, Zxy-Yann Jane

2015-02-01

Medical technology has transformed the body image of women and altered perceptions of beauty and sexual attraction. While "sexual attraction" is a fundamental concept in sexology, the characteristics of this concept have not been studied in the field of nursing. Because nurses provide advice and health education for women, it is essential to clarify the concept of sexual attraction for the benefit of related nursing research and for the further development of nursing knowledge. This study explores the concept of sexual attraction in a Taiwanese social context using concept analysis based on an evolutionary perspective. Inductive inquiry is used to compare and contrast articles from the academic literature, magazines, and newspapers, and data from participant observation and interviews are used to generate exemplars. The process by which the concept of sexual attraction has evolved over time is captured from three distinct aspects: significance, use, and application. The definitional statement of sexual attraction includes the five dimensions of: 1. sexual-oriented psychological dynamics; 2. personal aesthetics and sensory experience; 3. instinct body forces; 4. body language of self; and 5. social and cultural norms. This study scrutinized the changes in attributes that emphasize the biological, objectified body, and stereotyped gender roles of women. Further directions for research and nursing knowledge development are suggested. Examples include identifying the changes in the concept of sexual attraction that result from technological advancement and further clarifying the experiential knowledge of sexual attraction that represents the selfhood and independence of women in Taiwan.

Fokker-type dynamics with three-body correlations

International Nuclear Information System (INIS)

Salas, A.; Sanchez-Ron, J.M.

1981-01-01

Dynamical systems of N point particles without internal degrees of freedom are studied. Their equations of motion are derived from a Fokker-type variational principle with n-body correlations (n = 2,3,...,N), with special emphasis on the case n = 3. The distinction between n-body correlation and n-body effective force is analyzed in detail, with the help of an example. Maximal sets of independent three-body Poincare-invariant scalars are given. An example of three-body correlation formally similar to the usual two-body long-range scalar correlation is given and discussed. (author)

Body odor quality predicts behavioral attractiveness in humans.

Science.gov (United States)

Roberts, S Craig; Kralevich, Alexandra; Ferdenzi, Camille; Saxton, Tamsin K; Jones, Benedict C; DeBruine, Lisa M; Little, Anthony C; Havlicek, Jan

2011-12-01

Growing effort is being made to understand how different attractive physical traits co-vary within individuals, partly because this might indicate an underlying index of genetic quality. In humans, attention has focused on potential markers of quality such as facial attractiveness, axillary odor quality, the second-to-fourth digit (2D:4D) ratio and body mass index (BMI). Here we extend this approach to include visually-assessed kinesic cues (nonverbal behavior linked to movement) which are statistically independent of structural physical traits. The utility of such kinesic cues in mate assessment is controversial, particularly during everyday conversational contexts, as they could be unreliable and susceptible to deception. However, we show here that the attractiveness of nonverbal behavior, in 20 male participants, is predicted by perceived quality of their axillary body odor. This finding indicates covariation between two desirable traits in different sensory modalities. Depending on two different rating contexts (either a simple attractiveness rating or a rating for long-term partners by 10 female raters not using hormonal contraception), we also found significant relationships between perceived attractiveness of nonverbal behavior and BMI, and between axillary odor ratings and 2D:4D ratio. Axillary odor pleasantness was the single attribute that consistently predicted attractiveness of nonverbal behavior. Our results demonstrate that nonverbal kinesic cues could reliably reveal mate quality, at least in males, and could corroborate and contribute to mate assessment based on other physical traits.

Comparison of three empirical force fields for phonon calculations in CdSe quantum dots

Energy Technology Data Exchange (ETDEWEB)

Kelley, Anne Myers [Chemistry and Chemical Biology, University of California, Merced, 5200 North Lake Road, Merced, California 95343 (United States)

2016-06-07

Three empirical interatomic force fields are parametrized using structural, elastic, and phonon dispersion data for bulk CdSe and their predictions are then compared for the structures and phonons of CdSe quantum dots having average diameters of ~2.8 and ~5.2 nm (~410 and ~2630 atoms, respectively). The three force fields include one that contains only two-body interactions (Lennard-Jones plus Coulomb), a Tersoff-type force field that contains both two-body and three-body interactions but no Coulombic terms, and a Stillinger-Weber type force field that contains Coulombic interactions plus two-body and three-body terms. While all three force fields predict nearly identical peak frequencies for the strongly Raman-active “longitudinal optical” phonon in the quantum dots, the predictions for the width of the Raman peak, the peak frequency and width of the infrared absorption peak, and the degree of disorder in the structure are very different. The three force fields also give very different predictions for the variation in phonon frequency with radial position (core versus surface). The Stillinger-Weber plus Coulomb type force field gives the best overall agreement with available experimental data.

A study on the changes in attractive force of magnetic attachments for overdenture.

Science.gov (United States)

Leem, Han-Wool; Cho, In-Ho; Lee, Jong-Hyuk; Choi, Yu-Sung

2016-02-01

Although magnetic attachment is used frequently for overdenture, it is reported that attractive force can be decreased by abrasion and corrosion. The purpose of this study was to establish the clinical basis about considerations and long term prognosis of overdenture using magnetic attachments by investigating the change in attractive force of magnetic attachment applied to the patients. Among the patients treated with overdenture using magnetic attachments in Dankook University Dental Hospital, attractive force records of 61 magnetic attachments of 20 subjects who re-visited from July 2013 to June 2014 were analyzed. Dental magnet tester (Aichi Micro Intelligent Co., Aichi, Japan) was used for measurement. The magnetic attachments used in this study were Magfit IP-B Flat, Magfit DX400, Magfit DX600 and Magfit DX800 (Aichi Steel Co., Aichi, Japan) filled with Neodymium (NdFeB), a rare-earth magnet. Reduction ratio of attractive force had no significant correlation with conditional variables to which attachments were applied, and was higher when the maintenance period was longer (Pattractive force was significantly higher in the subject group in which attachments were used over 9 years than within 9 years (PAttractive force of magnetic attachment is maintained regardless of conditional variables and reduction ratio increased as the maintenance period became longer. Further study on adhesive material, attachment method and design improvement to prevent detachment of magnetic attachment is needed.

Evaluation of the attractive force of different types of new-generation magnetic attachment systems.

Science.gov (United States)

Akin, Hakan; Coskun, M Emre; Akin, E Gulsah; Ozdemir, A Kemal

2011-03-01

Rare earth magnets have been used in prosthodontics, but their tendency for corrosion in the oral cavity and insufficient attractive forces limit long-term clinical application. The purpose of this study was to evaluate the attractive force of different types of new-generation magnetic attachment systems. The attractive force of the neodymium-iron-boron (Nd-Fe-B) and samarium-cobalt (Sm-Co) magnetic attachment systems, including closed-field (Hilop and Hicorex) and open-field (Dyna and Steco) systems, was measured in a universal testing machine (n=5). The data were statistically evaluated with 1-way ANOVA and post hoc Tukey-Kramer multiple comparison test (α=.05). The closed-field systems exhibited greater (Pattractive force than the open-field systems. Moreover, there was a statistically significant difference in attractive force between Nd-Fe-B and Sm-Co magnets (Pattractive force was found with the Hilop system (9.2 N), and the lowest force was found with the Steco system (2.3 N). The new generation of Nd-Fe-B closed-field magnets, along with improved technology, provides sufficient denture retention for clinical application. Copyright © 2011 The Editorial Council of the Journal of Prosthetic Dentistry. Published by Mosby, Inc. All rights reserved.

Microscopic Theory for the Role of Attractive Forces in the Dynamics of Supercooled Liquids.

Science.gov (United States)

Dell, Zachary E; Schweizer, Kenneth S

2015-11-13

We formulate a microscopic, no adjustable parameter, theory of activated relaxation in supercooled liquids directly in terms of the repulsive and attractive forces within the framework of pair correlations. Under isochoric conditions, attractive forces can nonperturbatively modify slow dynamics, but at high enough density their influence vanishes. Under isobaric conditions, attractive forces play a minor role. High temperature apparent Arrhenius behavior and density-temperature scaling are predicted. Our results are consistent with recent isochoric simulations and isobaric experiments on a deeply supercooled molecular liquid. The approach can be generalized to treat colloidal gelation and glass melting, and other soft matter slow dynamics problems.

Molecular Theory and the Effects of Solute Attractive Forces on Hydrophobic Interactions.

Science.gov (United States)

Chaudhari, Mangesh I; Rempe, Susan B; Asthagiri, D; Tan, L; Pratt, L R

2016-03-03

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. 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.

Fluids with highly directional attractive forces. III. Multiple attraction sites

International Nuclear Information System (INIS)

Wertheim, M.S.

1986-01-01

The authors derive a reformulation of statistical thermodynamics for fluids of molecules which interact by highly directional attraction. The molecular model consists of a repulsive core and several sites of very short-ranged attraction. The authors explore the relationship between graph cancellation in the fugacity expansion and three types of steric incompatibility between repulsive and attractive interactions involving several molecules. The steric effects are used to best advantage in a limited regrouping of bonds. This controls the density parameters which appear when articulation points are eliminated in the graphical representation. Each density parameter is a singlet density for a species consisting of molecules with a specified set of sites bonded. The densities satisfy subsidiary conditions of internal consistency. These conditions are equivalent to a minimization of the Helmholtz free energy A. Graphical expressions for A and for the pressure are derived. Analogs of the s-particle direct correlation functions and of the Ornstein-Zernike equation are found

Three-Axis Ground Reaction Force Distribution during Straight Walking.

Science.gov (United States)

Hori, Masataka; Nakai, Akihito; Shimoyama, Isao

2017-10-24

We measured the three-axis ground reaction force (GRF) distribution during straight walking. Small three-axis force sensors composed of rubber and sensor chips were fabricated and calibrated. After sensor calibration, 16 force sensors were attached to the left shoe. The three-axis force distribution during straight walking was measured, and the local features of the three-axis force under the sole of the shoe were analyzed. The heel area played a role in receiving the braking force, the base area of the fourth and fifth toes applied little vertical or shear force, the base area of the second and third toes generated a portion of the propulsive force and received a large vertical force, and the base area of the big toe helped move the body's center of mass to the other foot. The results demonstrate that measuring the three-axis GRF distribution is useful for a detailed analysis of bipedal locomotion.

The estimation of body mass index and physical attractiveness is dependent on the observer's own body mass index.

Science.gov (United States)

Tovée, M J; Emery, J L; Cohen-Tovée, E M

2000-01-01

A disturbance in the evaluation of personal body mass and shape is a key feature of both anorexia and bulimia nervosa. However, it is uncertain whether overestimation is a causal factor in the development of these eating disorders or is merely a secondary effect of having a low body mass. Moreover, does this overestimation extend to the perception of other people's bodies? Since body mass is an important factor in the perception of physical attractiveness, we wanted to determine whether this putative overestimation of self body mass extended to include the perceived attractiveness of others. We asked 204 female observers (31 anorexic, 30 bulimic and 143 control) to estimate the body mass and rate the attractiveness of a set of 25 photographic images showing people of varying body mass index (BMI). BMI is a measure of weight scaled for height (kg m(- 2)). The observers also estimated their own BMI. Anorexic and bulimic observers systematically overestimated the body mass of both their own and other people's bodies, relative to controls, and they rated a significantly lower body mass to be optimally attractive. When the degree of overestimation is plotted against the BMI of the observer there is a strong correlation. Taken across all our observers, as the BMI of the observer declines, the overestimation of body mass increases. One possible explanation for this result is that the overestimation is a secondary effect caused by weight loss. Moreover, if the degree of body mass overestimation is taken into account, then there are no significant differences in the perceptions of attractiveness between anorexic and bulimic observers and control observers. Our results suggest a significant perceptual overestimation of BMI that is based on the observer's own BMI and not correlated with cognitive factors, and suggests that this overestimation in eating-disordered patients must be addressed directly in treatment regimes. PMID:11075712

Cues of upper body strength account for most of the variance in men's bodily attractiveness.

Science.gov (United States)

Sell, Aaron; Lukazsweski, Aaron W; Townsley, Michael

2017-12-20

Evolution equips sexually reproducing species with mate choice mechanisms that function to evaluate the reproductive consequences of mating with different individuals. Indeed, evolutionary psychologists have shown that women's mate choice mechanisms track many cues of men's genetic quality and ability to invest resources in the woman and her offspring. One variable that predicted both a man's genetic quality and his ability to invest is the man's formidability (i.e. fighting ability or resource holding power/potential). Modern women, therefore, should have mate choice mechanisms that respond to ancestral cues of a man's fighting ability. One crucial component of a man's ability to fight is his upper body strength. Here, we test how important physical strength is to men's bodily attractiveness. Three sets of photographs of men's bodies were shown to raters who estimated either their physical strength or their attractiveness. Estimates of physical strength determined over 70% of men's bodily attractiveness. Additional analyses showed that tallness and leanness were also favoured, and, along with estimates of physical strength, accounted for 80% of men's bodily attractiveness. Contrary to popular theories of men's physical attractiveness, there was no evidence of a nonlinear effect; the strongest men were the most attractive in all samples. © 2017 The Author(s).

Anorexia nervosa and body dysmorphic disorder: A comparison of body image concerns and explicit and implicit attractiveness beliefs.

Science.gov (United States)

Hartmann, A S; Thomas, J J; Greenberg, J L; Elliott, C M; Matheny, N L; Wilhelm, S

2015-06-01

Although body image is central to the etiological models of anorexia nervosa and body dysmorphic disorder, studies comparing body image and beliefs about attractiveness between the disorders are rare. Sixty-nine individuals (anorexia nervosa: n=24, body dysmorphic disorder: n=23, healthy controls: n=22) completed self-report measures (body image and general psychopathology), diagnostic interviews, and Go/No-Go Association tasks measuring implicit associations. Compared to controls, both clinical groups exhibited greater negative body image, a more negative attitude toward their physical selves, and more dysfunctional coping strategies (ps<.001). Also, both clinical groups shared greater explicit beliefs about the importance of attractiveness (ps<.001). In addition to supporting previous research with regard to comparable body image disturbance, this study also showed that beliefs regarding the importance of appearance (e.g., "one must be attractive to be successful") might be a fruitful target for therapy across both disorders. Copyright © 2015 Elsevier Ltd. All rights reserved.

Fluids with highly directional attractive forces. IV. Equilibrium polymerization

International Nuclear Information System (INIS)

Wertheim, M.S.

1986-01-01

The author investigates approximation methods for systems of molecules interacting by core repulsion and highly directional attraction due to several attraction sites. The force model chosen imitates a chemical bond by providing for bond saturation when binding occurs. The dense fluid is an equilibrium mixture of s-mers with mutual repulsion. The author uses a previously derived reformulation of statistical thermodynamics in which the particle species are monomeric units with a specified set of attraction sites bonded. Thermodynamic perturbation theory (TPT) and integral equations of two types are derived. The use of TPT is illustrated by explicit calculation for a molecular model with two attraction sites capable of forming chain and ring polymers. Successes and defects of TPT are discussed. The integral equations for pair correlations between particles of specified bonding include calculation of self-consistent densities of species. Methods of calculating thermodynamic properties from the solutions of integral equations are given

Efficient nonparametric n -body force fields from machine learning

Science.gov (United States)

Glielmo, Aldo; Zeni, Claudio; De Vita, Alessandro

2018-05-01

We provide a definition and explicit expressions for n -body Gaussian process (GP) kernels, which can learn any interatomic interaction occurring in a physical system, up to n -body contributions, for any value of n . The series is complete, as it can be shown that the "universal approximator" squared exponential kernel can be written as a sum of n -body kernels. These recipes enable the choice of optimally efficient force models for each target system, as confirmed by extensive testing on various materials. We furthermore describe how the n -body kernels can be "mapped" on equivalent representations that provide database-size-independent predictions and are thus crucially more efficient. We explicitly carry out this mapping procedure for the first nontrivial (three-body) kernel of the series, and we show that this reproduces the GP-predicted forces with meV /Å accuracy while being orders of magnitude faster. These results pave the way to using novel force models (here named "M-FFs") that are computationally as fast as their corresponding standard parametrized n -body force fields, while retaining the nonparametric character, the ease of training and validation, and the accuracy of the best recently proposed machine-learning potentials.

Nuclear structure with unitarily transformed two-body plus phenomenological three-body interactions

Energy Technology Data Exchange (ETDEWEB)

Guenther, Anneke

2011-02-02

The importance of three-nucleon forces for a variety of nuclear structure phenomena is apparent in various investigations. This thesis provides a first step towards the inclusion of realistic three-nucleon forces by studying simple phenomenological threebody interactions. The Unitary Correlation Operator Method (UCOM) and the Similarity Renormalization Group (SRG) provide two different approaches to derive soft phase-shift equivalent nucleon-nucleon (NN) interactions via unitary transformations. Although their motivations are quite different the NN interactions obtained with the two methods exhibit some similarities. The application of the UCOM- or SRG-transformed Argonne V18 potential in the Hartree-Fock (HF) approximation and including the second-order energy corrections emerging from many-body perturbation theory (MBPT) reveals that the systematics of experimental ground-state energies can be reproduced by some of the interactions considering a series of closed-shell nuclei across the whole nuclear chart. However, charge radii are systematically underestimated, especially for intermediate and heavy nuclei. This discrepancy to experimental data is expected to result from neglected three-nucleon interactions. As first ansatz for a three-nucleon force, we consider a finite-range three-body interaction of Gaussian shape. Its influence on ground-state energies and charge radii is discussed in detail on the basis of HF plus MBPT calculations and shows a significant improvement in the description of experimental data. As the handling of the Gaussian three-body interaction is time-extensive, we show that it can be replaced by a regularized three-body contact interaction exhibiting a very similar behavior. An extensive study characterizes its properties in detail and confirms the improvements with respect to nuclear properties. To take into account information of an exact numerical solution of the nuclear eigenvalue problem, the No-Core Shell Model is applied to

Quantifying the Attractive Force Exerted on the Pinned Calcium Spiral Waves by Using the Adventive Field

International Nuclear Information System (INIS)

Qiu Kang; Tang Jun; Luo Jin-Ming; Ma Jun

2013-01-01

The cytosolic calcium system is inhomogenous because of the discrete and random distribution of ion channels on the ER membrane. It is well known that the spiral tip can be pinned by the heterogenous area, and the field can detach the spiral from the heterogeneity. We use the adventive field to counteract the attractive force exerting on the calcium spiral wave by the heterogeneity, then the strength of the adventive field is used to quantify the attractive force indirectly. Two factors determining the attractive force are studied. It is found that: (1) the attractive force sharply increases with size of the heterogeneity for small-size heterogeneity, whereas the force increases to a saturated value for large-size heterogeneity; (2) for large-size heterogeneity, the force almost remains constant unless the level of the heterogeneity vanishes, the force decreases to zero linearly and sharply, and for small-size heterogeneity, the force decreases successively with the level of the heterogeneity. Furthermore, it is found that the forces exist only when the spiral tip is very close to the heterogenous area. Our study may shed some light on the control or suppression of the calcium spiral wave

Stability of the trapped nonconservative Gross-Pitaevskii equation with attractive two-body interaction

International Nuclear Information System (INIS)

Filho, Victo S.; Tomio, Lauro; Frederico, T.; Gammal, Arnaldo

2002-01-01

The dynamics of a nonconservative Gross-Pitaevskii equation for trapped atomic systems with attractive two-body interaction is numerically investigated, considering wide variations of the nonconservative parameters, related to atomic feeding and dissipation. We study the possible limitations of the mean-field description for an atomic condensate with attractive two-body interaction, by defining the parameter regions, where stable or unstable formation can be found. The present study is useful and timely considering the possibility of large variations of attractive two-body scattering lengths, which may be feasible in recent experiments

Three-body calculation of Be double-hypernuclei

Indian Academy of Sciences (India)

Energy levels and bond energy of the double- hypernucleus are calculated by considering two- and three-cluster interactions. Interactions between constituent particles are contact interactions for reproducing the low binding energy of nuclei. The effective action is constructed to involve three-body forces. In this paper ...

THE EXCITED LOADS OF ATTRACTION IN A SYMMETRICAL INDUCTOR SYSTEM FOR THE MAGNETIC PULSE REMOVING OF THE BODY CAR

Directory of Open Access Journals (Sweden)

A. V. Gnatov

2015-04-01

Full Text Available Recently, repair and recovery of vehicle body operations become more and more popular. A special place here is taken by equipment that provides performance of given repair operations. The most interesting are methods for recovery of car body panels that allow the straightening without disassembling of car body panels and damaging of existing protective coating. Now, there are several technologies for repair and recovery of car body panels without their disassembly and dismantling. The most perspective is magnetic-pulse technology of external noncontact straightening. Results. The calculation of excited loads attractions in a symmetrical inductor system in the universal tool of magnetic-pulse straightening is provided. According to the obtained analytical dependence of the numerical evaluation of volumetric construction diagrams, phase and amplitude of the radial dependence of the spatial distribution of the excited efforts of attraction is obtained. The influence of the magnetic properties of the blank screen and manifested in the appearance of powerful magnetic attraction forces is determined. Originality. A new trend of research of magnetic-pulse working of thin-walled metals has been formulated and received further development, which allows to create not only new equipment, but principally new technological processes of external non-contact repair and recovery of vehicle body panels. Scientific basis of electrodynamic and magnetic attraction of thin-walled sheet metals with using the energy of high-power pulsed fields was created for the first time and proved theoretically and experimentally. Scientific and technical solutions in design of effective tools based on single-turn inductor systems of cylindrical geometry for straightening and recovery of car body panels were formulated and proved theoretically, as well as experimentally. Practical value. Using the results of the calculations we can create effective tools for an external magnetic

Attractive forces between hydrophobic solid surfaces measured by AFM on the first approach in salt solutions and in the presence of dissolved gases.

Science.gov (United States)

Azadi, Mehdi; Nguyen, Anh V; Yakubov, Gleb E

2015-02-17

Interfacial gas enrichment of dissolved gases (IGE) has been shown to cover hydrophobic solid surfaces in water. The atomic force microscopy (AFM) data has recently been supported by molecular dynamics simulation. It was demonstrated that IGE is responsible for the unexpected stability and large contact angle of gaseous nanobubbles at the hydrophobic solid-water interface. Here we provide further evidence of the significant effect of IGE on an attractive force between hydrophobic solid surfaces in water. The force in the presence of dissolved gas, i.e., in aerated and nonaerated NaCl solutions (up to 4 M), was measured by the AFM colloidal probe technique. The effect of nanobubble bridging on the attractive force was minimized or eliminated by measuring forces on the first approach of the AFM probe toward the flat hydrophobic surface and by using high salt concentrations to reduce gas solubility. Our results confirm the presence of three types of forces, two of which are long-range attractive forces of capillary bridging origin as caused by either surface nanobubbles or gap-induced cavitation. The third type is a short-range attractive force observed in the absence of interfacial nanobubbles that is attributed to the IGE in the form of a dense gas layer (DGL) at hydrophobic surfaces. Such a force was found to increase with increasing gas saturation and to decrease with decreasing gas solubility.

On the axioms of the forces in the mechanics of rigid bodies

Directory of Open Access Journals (Sweden)

Lámer Géza

2017-01-01

Full Text Available Newton summarised knowledge related to forces in three axioms. The first and second ones define the mechanical state and motion of the examined body when there is no force or when force is exerted on the body. The third defines the law of action and reaction. Newton did not define it as separate axiom but assumed that forces are completely independent from each other. The statics applies four axioms. The first applies to the balance of two forces while the second one applies of three forces. The third axiom defines the relationships inside an equilibrium force system. The fourth one is the axiom of action and reaction. The two axiom systems are independent from each other. Further the independent axioms are applied in case of constraint forces: frictionless reaction force orthogonal on the forced surface, friction force acts in the direction of the motion, the deformation can be elastic, plastic and viscous.

Attraction of semiconductor nanowires: An in situ observation

International Nuclear Information System (INIS)

Chen, Bin; Gao, Qiang; Chang, Li; Wang, Yanbo; Chen, Zibin; Liao, Xiaozhou; Tan, Hark Hoe; Zou, Jin; Ringer, Simon P.; Jagadish, Chennupati

2013-01-01

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

Factors related to depression and eating disorders: self-esteem, body image, and attractiveness.

Science.gov (United States)

Grubb, H J; Sellers, M I; Waligroski, K

1993-06-01

To test hypotheses that women suffering from some form of eating disorder would experience lower self-esteem and higher depression and that women with lower self-esteem and greater depression would rate their attractiveness lower and see themselves as heavier than less depressed individuals, 42 college undergraduate women were individually administered the Eating Disorders Inventory, Beck Depression Inventory, Coopersmith Self-esteem Inventory, and a Body Image/Attractiveness Perception Scale. A Pearson correlation indicated a substantial relation between scores on depression and scores on eating disorders, but nonsignificant values between self-esteem scores and scores on either eating disorders or on depression. Depression scores correlated significantly with rated body size, but not attractiveness, while self-esteem scores were significantly correlated with rated attractiveness, not body size. These results contradict literature on the relation between self-esteem and depression. Directions for additional research are discussed.

Self-bridging of vertical silicon nanowires and a universal capacitive force model for spontaneous attraction in nanostructures.

Science.gov (United States)

Sun, Zhelin; Wang, Deli; Xiang, Jie

2014-11-25

Spontaneous attractions between free-standing nanostructures have often caused adhesion or stiction that affects a wide range of nanoscale devices, particularly nano/microelectromechanical systems. Previous understandings of the attraction mechanisms have included capillary force, van der Waals/Casimir forces, and surface polar charges. However, none of these mechanisms universally applies to simple semiconductor structures such as silicon nanowire arrays that often exhibit bunching or adhesions. Here we propose a simple capacitive force model to quantitatively study the universal spontaneous attraction that often causes stiction among semiconductor or metallic nanostructures such as vertical nanowire arrays with inevitably nonuniform size variations due to fabrication. When nanostructures are uniform in size, they share the same substrate potential. The presence of slight size differences will break the symmetry in the capacitive network formed between the nanowires, substrate, and their environment, giving rise to electrostatic attraction forces due to the relative potential difference between neighboring wires. Our model is experimentally verified using arrays of vertical silicon nanowire pairs with varied spacing, diameter, and size differences. Threshold nanowire spacing, diameter, or size difference between the nearest neighbors has been identified beyond which the nanowires start to exhibit spontaneous attraction that leads to bridging when electrostatic forces overcome elastic restoration forces. This work illustrates a universal understanding of spontaneous attraction that will impact the design, fabrication, and reliable operation of nanoscale devices and systems.

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.

Algebraic diagrammatic construction formalism with three-body interactions

Science.gov (United States)

Raimondi, Francesco; Barbieri, Carlo

2018-05-01

Background: Self-consistent Green's function theory has recently been extended to the basic formalism needed to account for three-body interactions [Carbone, Cipollone, Barbieri, Rios, and Polls, Phys. Rev. C 88, 054326 (2013), 10.1103/PhysRevC.88.054326]. The contribution of three-nucleon forces has so far been included in ab initio calculations on nuclear matter and finite nuclei only as averaged two-nucleon forces. Purpose: We derive the working equations for all possible two- and three-nucleon terms that enter the expansion of the self-energy up to the third order, thus including the interaction-irreducible (i.e., not averaged) diagrams with three-nucleon forces that have been previously neglected. Methods: We employ the algebraic diagrammatic construction up to the third order as an organization scheme for generating a nonperturbative self-energy, in which ring (particle-hole) and ladder (particle-particle) diagrams are resummed to all orders. Results: We derive expressions of the static and dynamic self-energy up to the third order, by taking into account the set of diagrams required when either the skeleton or nonskeleton expansions of the single-particle propagator are assumed. A hierarchy of importance among different diagrams is revealed, and a particular emphasis is given to a third-order diagram [see Fig. 2(c)] that is expected to play a significant role among those featuring an interaction-irreducible three-nucleon force. Conclusion: A consistent formalism to resum at infinite order correlations induced by three-nucleon forces in the self-consistent Green's function theory is now available and ready to be implemented in the many-body solvers.

Tensor force and delta excitation for the structure of light nuclei

International Nuclear Information System (INIS)

Horii, K; Myo, T; Toki, H

2014-01-01

We treat explicitly Δ(1232) isobar degrees of freedom using a bare nucleon-nucleon interaction for few-body systems, where Δ excitations can be the origin of the three-body force via the pion exchange. We adopt the Argonne two-body potential including Δ, named as AV28 potential, and study the role of Δ explicitly in two-body and three-body systems. It was found that the additional Δ states generate strong tensor correlations caused by the transitions between N and Δ states, and change tensor matrix elements largely from the results with only nucleons. We studied the effects of three-body force in the triton and obtained 0.8 MeV attraction due to the intermediate Δ excitation. Due to the lack of the total binding energy for the triton in the delta model, we further studied carefully the effects of the delta excitation in various two body channels and compared with the nucleon only model in the AV14 potential. We modified slightly the AV28 potential in the singlet S channel so that we could reproduce the triton binding energy due to the appropriate amount of the three-body force effects

Attractive celebrity and peer images on Instagram: Effect on women's mood and body image.

Science.gov (United States)

Brown, Zoe; Tiggemann, Marika

2016-12-01

A large body of research has documented that exposure to images of thin fashion models contributes to women's body dissatisfaction. The present study aimed to experimentally investigate the impact of attractive celebrity and peer images on women's body image. Participants were 138 female undergraduate students who were randomly assigned to view either a set of celebrity images, a set of equally attractive unknown peer images, or a control set of travel images. All images were sourced from public Instagram profiles. Results showed that exposure to celebrity and peer images increased negative mood and body dissatisfaction relative to travel images, with no significant difference between celebrity and peer images. This effect was mediated by state appearance comparison. In addition, celebrity worship moderated an increased effect of celebrity images on body dissatisfaction. It was concluded that exposure to attractive celebrity and peer images can be detrimental to women's body image. Copyright © 2016 Elsevier Ltd. All rights reserved.

Exact calculation of three-body contact interaction to second order

International Nuclear Information System (INIS)

Kaiser, N.

2012-01-01

For a system of fermions with a three-body contact interaction the second-order contributions to the energy per particle anti E(k f ) are calculated exactly. The three-particle scattering amplitude in the medium is derived in closed analytical form from the corresponding two-loop rescattering diagram. We compare the (genuine) second-order three-body contribution to anti E(k f )∝k f 10 with the second-order term due to the density-dependent effective two-body interaction, and find that the latter term dominates. The results of the present study are of interest for nuclear many-body calculations where chiral three-nucleon forces are treated beyond leading order via a density-dependent effective two-body interaction. (orig.)

Female waist-to-hip ratio, body mass index and sexual attractiveness in China

Directory of Open Access Journals (Sweden)

B.J. DIXSON, Baoguo LI, A.F. DIXSON

2010-04-01

Full Text Available Men and women at Northwest University (n = 751, Xi’an, China were asked to judge the attractiveness of photographs of female patients who had undergone micrograft surgery to reduce their waist-to-hip ratios (WHR. Micrograft surgery involves harvesting adipose tissue from the waist and reshaping the buttocks to produce a low WHR and an ‘hourglass’ female figure. This gynoid distribution of female body fat has been shown to correlate with measures of fertility and health. Significantly larger numbers of subjects, of both sexes, chose post-operative photographs, with lower WHRs, as more attractive than pre-operative photographs of the same women. Some patients had gained, and some had lost weight, post-operatively, with resultant changes in body mass index (BMI. However, these changes in BMI were not related to judgments of attractiveness. These results show that the hourglass female figure is rated as attractive in China, and that WHR, rather than BMI, plays a crucial role in such attractiveness judgments [Current Zoology 56 (2: 175–181, 2010].

Measured long-range repulsive Casimir-Lifshitz forces.

Science.gov (United States)

Munday, J N; Capasso, Federico; Parsegian, V Adrian

2009-01-08

Quantum fluctuations create intermolecular forces that pervade macroscopic bodies. At molecular separations of a few nanometres or less, these interactions are the familiar van der Waals forces. However, as recognized in the theories of Casimir, Polder and Lifshitz, at larger distances and between macroscopic condensed media they reveal retardation effects associated with the finite speed of light. Although these long-range forces exist within all matter, only attractive interactions have so far been measured between material bodies. Here we show experimentally that, in accord with theoretical prediction, the sign of the force can be changed from attractive to repulsive by suitable choice of interacting materials immersed in a fluid. The measured repulsive interaction is found to be weaker than the attractive. However, in both cases the magnitude of the force increases with decreasing surface separation. Repulsive Casimir-Lifshitz forces could allow quantum levitation of objects in a fluid and lead to a new class of switchable nanoscale devices with ultra-low static friction.

A non-orthogonal harmonic-oscillator basis for three-body problems

International Nuclear Information System (INIS)

Agrello, D.A.; Aguilera-Navarro, V.C.; Chacon, E.

1979-01-01

A set of harmonic-oscillator states suitable for the representation of the wave function of the bound states of a system of three identical particles, is presented. As an illustration of the possibilities of the states defined in this paper, they are applied in a variational determination of the lowest symmetric S state of 12 C, in the model of three structureless α particles interacting through the Coulomb force plus a phenomenological two-body force. (author) [pt

Topics in three body problems

International Nuclear Information System (INIS)

Amado, R.D.

1975-01-01

An overview of the formal theory of the three-body problem as it has developed in the past twelve years is given. The formal structure of the theory, some of the techniques that have developed for handling the theory, and some results on how general quantum mechanical principles structure the results, are presented. The discussion is held entirely in the context of non-relativistic quantum mechanics with short-range forces. In this presentation the main outline of the theory is stressed, often at the expense of mathematical rigour [pt

Penis size interacts with body shape and height to influence male attractiveness.

Science.gov (United States)

Mautz, Brian S; Wong, Bob B M; Peters, Richard A; Jennions, Michael D

2013-04-23

Compelling evidence from many animal taxa indicates that male genitalia are often under postcopulatory sexual selection for characteristics that increase a male's relative fertilization success. There could, however, also be direct precopulatory female mate choice based on male genital traits. Before clothing, the nonretractable human penis would have been conspicuous to potential mates. This observation has generated suggestions that human penis size partly evolved because of female choice. Here we show, based upon female assessment of digitally projected life-size, computer-generated images, that penis size interacts with body shape and height to determine male sexual attractiveness. Positive linear selection was detected for penis size, but the marginal increase in attractiveness eventually declined with greater penis size (i.e., quadratic selection). Penis size had a stronger effect on attractiveness in taller men than in shorter men. There was a similar increase in the positive effect of penis size on attractiveness with a more masculine body shape (i.e., greater shoulder-to-hip ratio). Surprisingly, larger penis size and greater height had almost equivalent positive effects on male attractiveness. Our results support the hypothesis that female mate choice could have driven the evolution of larger penises in humans. More broadly, our results show that precopulatory sexual selection can play a role in the evolution of genital traits.

Discrete Lattice effect of various forcing methods of body force on immersed Boundary-Lattice Boltzmann method

Energy Technology Data Exchange (ETDEWEB)

Son, Sung Wan; Ha, Man Yeong; Yoon, Hyun Sik [Pusan National University, Busan (Korea, Republic of); Jeong, Hae Kwon [POSCO, Pohang (Korea, Republic of); Balachandar, S. [University of Florida, Florida (United States)

2013-02-15

We investigate the discrete lattice effect of various forcing methods in the lattice Boltzmann method (LBM) to include the body force obtained from the immersed boundary method (IBM). In the immersed boundary lattice Boltzmann method (IB-LBM), the LBM needs a forcing method to involve the body force on a forcing point near the immersed boundary that is calculated by IBM. The proper forcing method in LBM is derived to include the body force, which appears to resolve problems such as multiphase flow, non-ideal gas behavior, etc. Many researchers have adopted different forcing methods in LBM to involve the body force from IBM, even when they solved similar problems. However, it is necessary to evaluate the discrete lattice effect, which originates from different forcing methods in LBM, to include the effect of the body force from IBM on the results. Consequently, in this study, a rigorous analysis of the discrete lattice effect for different forcing methods in IB-LBM is performed by solving various problems.

Discrete Lattice effect of various forcing methods of body force on immersed Boundary-Lattice Boltzmann method

International Nuclear Information System (INIS)

Son, Sung Wan; Ha, Man Yeong; Yoon, Hyun Sik; Jeong, Hae Kwon; Balachandar, S.

2013-01-01

We investigate the discrete lattice effect of various forcing methods in the lattice Boltzmann method (LBM) to include the body force obtained from the immersed boundary method (IBM). In the immersed boundary lattice Boltzmann method (IB-LBM), the LBM needs a forcing method to involve the body force on a forcing point near the immersed boundary that is calculated by IBM. The proper forcing method in LBM is derived to include the body force, which appears to resolve problems such as multiphase flow, non-ideal gas behavior, etc. Many researchers have adopted different forcing methods in LBM to involve the body force from IBM, even when they solved similar problems. However, it is necessary to evaluate the discrete lattice effect, which originates from different forcing methods in LBM, to include the effect of the body force from IBM on the results. Consequently, in this study, a rigorous analysis of the discrete lattice effect for different forcing methods in IB-LBM is performed by solving various problems.

[Evaluation of three dimensional orthodontic force produced by magnet of fix appliance].

Science.gov (United States)

Dai, Xin; Hou, Zhi-ming; Yao, Ge; Wen, Jing-long

2008-12-01

To analyze the feature and magnitude of three dimensional orthodontic force produced by the magnet of fix appliance. Forces detected by universal fatigue test system included the attractive and repulsive,the inclined and rotated orthodontic forces of two magnets in different air gaps, and the integrated inclined and rotated orthodontic forces of two magnets and NiTi wire. The attractive and repulsive forces of two magnets were 4.68 to 0.45 N and 3.00 to 0.40 N respectively in the air gaps of 0 to 5 mm. The inclined orthodontic forces were 1.54 to 1.67 N, 0.63 to 0.69 N, 0.47 to 0.54 N when the magnets were vertically inclined 10 degrees to 40 degrees in the air gaps of 0, 1, 2mm. The rotated orthodontic forces were 0.97 to 1.32 N, 0.53 to 0.59 N, 0.39 to 0.48 N when the magnets were horizontally rotated 10 degrees to 40 degrees in the air gaps of 0, 1, 2mm. The integrated orthodontic force of two magnets and 0.014-inch NiTi wire was 0.32 to 0.5 N when the magnets was vertically inclined 10 degrees to 40 degrees in the air gap of 4 mm. The integrated orthodontic force of two magnets and 0.012-inch NiTi wire was 0.32 to 0.39 N when the magnets were horizontally rotated 10 degrees to 40 degrees in the air gap of 3 mm. Magnets made into orthodontic brackets to some extent could replace the mechanical orthodontic force produced by orthodontic wires and elastics.

Evolved chiral Hamiltonians at the three-body level and beyond

Energy Technology Data Exchange (ETDEWEB)

Calci, Angelo

2014-07-14

Based on the fundamental symmetries of QCD, chiral effective field theory (EFT) provides two- (NN), three- (3N), four- (4N), and many-nucleon interactions in a consistent and systematic scheme. Recent developments to construct chiral NN+3N interactions at different chiral orders and regularizations enable exciting nuclear structure investigations as well as a quantification of the fundamental uncertainties resulting from the chiral expansion and regularization. We present the complete toolchain to employ the present and future chiral NN, 3N, and 4N interactions in nuclear structure calculations and emphasize technical developments in the three- and four-body space, such as the similarity renormalization group (SRG), the frequency conversion, and the transformation to the JT-coupled scheme. We study the predictions of the chiral NN+3N interactions in ab initio nuclear structure calculations with the importance-truncated no-core shell model and coupled-cluster approach. We demonstrate that the inclusion of chiral 3N forces improves the overall agreement with experiment for excitation energies of p-shell nuclei and it qualitatively reproduces the systematics of nuclear binding energies throughout the nuclear chart up to heavy tin isotopes. In this context it is necessary to introduce truncations in the three-body model space and we carefully analyze their impact and confirm the reliability of the reported results. The SRG evolution induces many-nucleon forces that generally cannot be included in the calculations and constitute a major limitation for the applicability of SRG-evolved chiral forces. We study the origin and effect of the induced many-nucleon forces and propose a modification of the interaction, which suppresses the induced beyond-3N forces. This enables applications of the chiral interactions far beyond the mid-p shell. Furthermore, we test alternative formulations of SRG generators aiming to prevent the induced many-body forces from the outset. The

Measured long-range repulsive Casimir–Lifshitz forces

Science.gov (United States)

Munday, J. N.; Capasso, Federico; Parsegian, V. Adrian

2014-01-01

Quantum fluctuations create intermolecular forces that pervade macroscopic bodies1–3. At molecular separations of a few nanometres or less, these interactions are the familiar van der Waals forces4. However, as recognized in the theories of Casimir, Polder and Lifshitz5–7, at larger distances and between macroscopic condensed media they reveal retardation effects associated with the finite speed of light. Although these long-range forces exist within all matter, only attractive interactions have so far been measured between material bodies8–11. Here we show experimentally that, in accord with theoretical prediction12, the sign of the force can be changed from attractive to repulsive by suitable choice of interacting materials immersed in a fluid. The measured repulsive interaction is found to be weaker than the attractive. However, in both cases the magnitude of the force increases with decreasing surface separation. Repulsive Casimir–Lifshitz forces could allow quantum levitation of objects in a fluid and lead to a new class of switchable nanoscale devices with ultra-low static friction13–15. PMID:19129843

A pilot study on body image, attractiveness and body size in Gambians living in an urban community.

Science.gov (United States)

Siervo, M; Grey, P; Nyan, O A; Prentice, A M

2006-06-01

We investigated the attitudinal and perceptual components of body image and its link with body mass index (BMI) in a sample of urban Gambians. We also looked at cross-cultural differences in body image and views on attractiveness between Gambians and Americans. Four groups of 50 subjects were assessed: men 14- 25y (YM); women 14-25y (YW); men 35-50y (OM); women 35-50y (OW). Socio-economic status, education, healthy lifestyle and western influences were investigated. Height and weight were measured. Body dissatisfaction was assessed with the body dissatisfaction scale of the Eating Disorder Inventory. Perceptions of body image and attractiveness were assessed using the Body Image Assessment for Obesity (BIA-O) and Figure Rating Scale (FRS). Different generations of Gambians had very different perceptions and attitudes towards obesity. Current body size was realistically perceived and largely well tolerated. Older women had a higher body discrepancy (current minus ideal body size) than other groups (pbody size until they were overweight (BMI=27.8 kg/m2), whilst OM, YM and YW started to be concerned at a BMI respectively of 22.9, 19.8 and 21.5 kg/m2. A cross-cultural comparison using published data on FRS showed that Gambians were more obesity tolerant than black and white Americans. The Gambia is a country in the early stage of demographic transitions but in urban areas there is an increase in obesity prevalence. Inherent tensions between the preservation of cultural values and traditional habits, and raising awareness of the risks of obesity, may limit health interventions to prevent weight gain.

The force-distance properties of attracting magnetic attachments for tooth movement in combination with clear sequential aligners.

Science.gov (United States)

Phelan, Angie; Petocz, Peter; Walsh, William; Darendeliler, M Ali

2012-11-01

The demand for clear sequential aligner therapy has increased dramatically in recent years. An improved system utilising small neodymium-iron-boron (NdFeB) magnetic attachments has been proposed to enhance appliance capabilities. The aim of the investigation was to analyse the force system diagrams produced by small attracting NdFeB magnets to determine, 1) whether the force levels were sufficient to induce tooth movement, 2) the effect of magnet morphology on force characteristics and, 3) the most appropriate magnet dimensions that could be utilised for this application. Twenty-nine NdFeB rectangular magnets of varying dimensions were tested. A Mach-1 universal testing machine (Biosyntech Inc, Quebec, Canada) was used to measure the attractive force of pairs of magnets. Measurements commenced with a magnetic pair in contact and subsequently vertically separated a distance of 10 mm at a speed of 12 mm/minute. For all magnetic configurations four repeat measurements were performed on five magnetic pairs of the same size. The force-distance diagrams for all magnet configurations demonstrated a dramatic decrease in force with increasing magnet separation. Rather than a suggested inverse square law, the experimental data followed an inverse fourth law when an offset determined by a regression analysis was applied to the distance. For the majority of magnets, insignificant forces were attained beyond 2 mm of separation. Magnets with large pole face areas and longer magnetic axes provided the greatest force. A select range of magnet configurations exhibited suitable and reliable attractive forces and therefore could be advocated for prescribed clinical application.

Ground reaction forces during level ground walking with body weight unloading

Science.gov (United States)

Barela, Ana M. F.; de Freitas, Paulo B.; Celestino, Melissa L.; Camargo, Marcela R.; Barela, José A.

2014-01-01

Background: Partial body weight support (BWS) systems have been broadly used with treadmills as a strategy for gait training of individuals with gait impairments. Considering that we usually walk on level ground and that BWS is achieved by altering the load on the plantar surface of the foot, it would be important to investigate some ground reaction force (GRF) parameters in healthy individuals walking on level ground with BWS to better implement rehabilitation protocols for individuals with gait impairments. Objective: To describe the effects of body weight unloading on GRF parameters as healthy young adults walked with BWS on level ground. Method: Eighteen healthy young adults (27±4 years old) walked on a walkway, with two force plates embedded in the middle of it, wearing a harness connected to a BWS system, with 0%, 15%, and 30% BWS. Vertical and horizontal peaks and vertical valley of GRF, weight acceptance and push-off rates, and impulse were calculated and compared across the three experimental conditions. Results: Overall, participants walked more slowly with the BWS system on level ground compared to their normal walking speed. As body weight unloading increased, the magnitude of the GRF forces decreased. Conversely, weight acceptance rate was similar among conditions. Conclusions: Different amounts of body weight unloading promote different outputs of GRF parameters, even with the same mean walk speed. The only parameter that was similar among the three experimental conditions was the weight acceptance rate. PMID:25590450

Ground reaction forces during level ground walking with body weight unloading

Directory of Open Access Journals (Sweden)

Ana M. F. Barela

2014-12-01

Full Text Available Background: Partial body weight support (BWS systems have been broadly used with treadmills as a strategy for gait training of individuals with gait impairments. Considering that we usually walk on level ground and that BWS is achieved by altering the load on the plantar surface of the foot, it would be important to investigate some ground reaction force (GRF parameters in healthy individuals walking on level ground with BWS to better implement rehabilitation protocols for individuals with gait impairments. Objective: To describe the effects of body weight unloading on GRF parameters as healthy young adults walked with BWS on level ground. Method: Eighteen healthy young adults (27±4 years old walked on a walkway, with two force plates embedded in the middle of it, wearing a harness connected to a BWS system, with 0%, 15%, and 30% BWS. Vertical and horizontal peaks and vertical valley of GRF, weight acceptance and push-off rates, and impulse were calculated and compared across the three experimental conditions. Results: Overall, participants walked more slowly with the BWS system on level ground compared to their normal walking speed. As body weight unloading increased, the magnitude of the GRF forces decreased. Conversely, weight acceptance rate was similar among conditions. Conclusions: Different amounts of body weight unloading promote different outputs of GRF parameters, even with the same mean walk speed. The only parameter that was similar among the three experimental conditions was the weight acceptance rate.

Double standards in body evaluation? The influence of identification with body stimuli on ratings of attractiveness, body fat, and muscle mass.

Science.gov (United States)

Voges, Mona M; Giabbiconi, Claire-Marie; Schöne, Benjamin; Waldorf, Manuel; Hartmann, Andrea S; Vocks, Silja

2017-10-20

Although it is well documented that women evaluate their own body differently from other bodies, it remains unclear whether this discrepancy is based on double standards because of identity or on objective differences between these bodies. The aim of this study was therefore to test whether women apply double standards depending on a body's identity when evaluating the same bodies presented with different faces. Average-weight women (N = 104) rated body attractiveness, body fat, and muscle mass of thin, average-weight, overweight, athletic, and hypermuscular bodies with either another female's face or their own face. With their own face, subjects rated overweight bodies as more unattractive, higher in body fat and lower in muscle mass than with another female's face. However, for non-overweight bodies, body ratings did not differ depending on body identity. Based on the self-deprecating double standards for overweight bodies, a body-related identity bias might be considered in theoretical models of body image. Level of evidence Level V, descriptive study.

Three-body vertices with two-body techniques

International Nuclear Information System (INIS)

Mitra, A.N.; Sharma, V.K.

1976-01-01

It has long been recognized that vertex functions for few particle systems provide a convenient medium for the analysis of reactions in the language of Feynman diagrams, analogously to elementary particle processes. The development of three-particle theory during the last decade has provided considerably more impetus for the use of the language of three-body vertex functions through the possibility of their 'exact' evaluations with only two-body input. While three-body vertices are probably superfluous for the description of only three-body processes (for which exact amplitudes are already available) their practical usefulness often extends to reactions involving more than three-particle systems (for which 'exact' amplitudes are still a distant goal), as long as such systems can be meaningfully described in terms of not more than three particles playing the active role. This paper investigates a simplified construction of three-body vertices. This must check against their standard definition as overlap integral. Unfortunately this definition involves a non-trivial normalization of three-body wave functions with realistic NN potentials, and has little practical scope for extension beyond A=3. (Auth.)

Forces and moments on a slender, cavitating body

Energy Technology Data Exchange (ETDEWEB)

Hailey, C.E.; Clark, E.L.; Buffington, R.J.

1988-01-01

Recently a numerical code has been developed at Sandia National Laboratories to predict the pitching moment, normal force, and axial force of a slender, supercavitating shape. The potential flow about the body and cavity is calculated using an axial distribution of source/sink elements. The cavity surface is assumed to be a constant pressure streamline, extending beyond the base of the model. Slender body approximation is used to model the crossflow for small angles of attack. A significant extension of previous work in cavitation flow is the inclusion of laminar and turbulent boundary layer solutions on the body. Predictions with this code, for axial force at zero angle of attack, show good agreement with experiments. There are virtually no published data availble with which to benchmark the pitching moment and normal force predictions. An experiment was designed to measure forces and moments on a supercavitation shape. The primary reason for the test was to obtain much needed data to benchmark the hydrodynamic force and moment predictions. Since the numerical prediction is for super cavitating shapes at very small cavitation numbers, the experiment was designed to be a ventilated cavity test. This paper describes the experimental procedure used to measure the pitching moment, axial and normal forces, and base pressure on a slender body with a ventilated cavity. Limited results are presented for pitching moment and normal force. 5 refs., 7 figs.

Analysis of Attentional Bias towards Attractive and Unattractive Body Regions among Overweight Males and Females: An Eye-Movement Study.

Directory of Open Access Journals (Sweden)

Petra Warschburger

Full Text Available Body image distortion is highly prevalent among overweight individuals. Whilst there is evidence that body-dissatisfied women and those suffering from disordered eating show a negative attentional bias towards their own unattractive body parts and others' attractive body parts, little is known about visual attention patterns in the area of obesity and with respect to males. Since eating disorders and obesity share common features in terms of distorted body image and body dissatisfaction, the aim of this study was to examine whether overweight men and women show a similar attentional bias.We analyzed eye movements in 30 overweight individuals (18 females and 28 normal-weight individuals (16 females with respect to the participants' own pictures as well as gender- and BMI-matched control pictures (front and back view. Additionally, we assessed body image and disordered eating using validated questionnaires.The overweight sample rated their own body as less attractive and showed a more disturbed body image. Contrary to our assumptions, they focused significantly longer on attractive compared to unattractive regions of both their own and the control body. For one's own body, this was more pronounced for women. A higher weight status and more frequent body checking predicted attentional bias towards attractive body parts. We found that overweight adults exhibit an unexpected and stable pattern of selective attention, with a distinctive focus on their own attractive body regions despite higher levels of body dissatisfaction. This positive attentional bias may either be an indicator of a more pronounced pattern of attentional avoidance or a self-enhancing strategy. Further research is warranted to clarify these results.

Analysis of Attentional Bias towards Attractive and Unattractive Body Regions among Overweight Males and Females: An Eye-Movement Study.

Science.gov (United States)

Warschburger, Petra; Calvano, Claudia; Richter, Eike M; Engbert, Ralf

2015-01-01

Body image distortion is highly prevalent among overweight individuals. Whilst there is evidence that body-dissatisfied women and those suffering from disordered eating show a negative attentional bias towards their own unattractive body parts and others' attractive body parts, little is known about visual attention patterns in the area of obesity and with respect to males. Since eating disorders and obesity share common features in terms of distorted body image and body dissatisfaction, the aim of this study was to examine whether overweight men and women show a similar attentional bias. We analyzed eye movements in 30 overweight individuals (18 females) and 28 normal-weight individuals (16 females) with respect to the participants' own pictures as well as gender- and BMI-matched control pictures (front and back view). Additionally, we assessed body image and disordered eating using validated questionnaires. The overweight sample rated their own body as less attractive and showed a more disturbed body image. Contrary to our assumptions, they focused significantly longer on attractive compared to unattractive regions of both their own and the control body. For one's own body, this was more pronounced for women. A higher weight status and more frequent body checking predicted attentional bias towards attractive body parts. We found that overweight adults exhibit an unexpected and stable pattern of selective attention, with a distinctive focus on their own attractive body regions despite higher levels of body dissatisfaction. This positive attentional bias may either be an indicator of a more pronounced pattern of attentional avoidance or a self-enhancing strategy. Further research is warranted to clarify these results.

Pionic retardation effects in two-pion-exchange three-nucleon forces

International Nuclear Information System (INIS)

Coon, S.A.; Friar, J.L.

1986-01-01

Those two-pion-exchange three-nucleon forces which arise from nuclear processes that involve only pions and nucleons are calculated. Among the processes which contribute are pion seagulls (e.g., nucleon-antinucleon pair terms) and overlapping, retarded pion exchanges. The resulting potential is shown to be a (v/c) 2 relativistic correction, and satisfies nontrivial constraints from special relativity. The relativistic ambiguities found before in treatments of relativistic corrections to the one-pion-exchange nuclear charge operator and two-body potential are also present in the three-nucleon potential. The resulting three-nucleon force differs from the original Tucson-Melbourne potential only in the presence of several new nonlocal terms, and in the specification of the choice of ambiguity parameters in the latter potential

Pionic retardation effects in two-pion-exchange three-nucleon forces

Science.gov (United States)

Coon, S. A.; Friar, J. L.

1986-09-01

Those two-pion-exchange three-nucleon forces which arise from nuclear processes that involve only pions and nucleons are calculated. Among the processes which contribute are pion seagulls (e.g., nucleon-antinucleon pair terms) and overlapping, retarded pion exchanges. The resulting potential is shown to be a (v/c)2 relativistic correction, and satisfies nontrivial constraints from special relativity. The relativistic ambiguities found before in treatments of relativistic corrections to the one-pion-exchange nuclear charge operator and two-body potential are also present in the three-nucleon potential. The resulting three-nucleon force differs from the original Tucson-Melbourne potential only in the presence of several new nonlocal terms, and in the specification of the choice of ambiguity parameters in the latter potential.

Pionic retardation effects in two-pion-exchange three-nucleon forces

Energy Technology Data Exchange (ETDEWEB)

Coon, S.A.; Friar, J.L.

1986-09-01

Those two-pion-exchange three-nucleon forces which arise from nuclear processes that involve only pions and nucleons are calculated. Among the processes which contribute are pion seagulls (e.g., nucleon-antinucleon pair terms) and overlapping, retarded pion exchanges. The resulting potential is shown to be a (v-italic/c-italic)/sup 2/ relativistic correction, and satisfies nontrivial constraints from special relativity. The relativistic ambiguities found before in treatments of relativistic corrections to the one-pion-exchange nuclear charge operator and two-body potential are also present in the three-nucleon potential. The resulting three-nucleon force differs from the original Tucson-Melbourne potential only in the presence of several new nonlocal terms, and in the specification of the choice of ambiguity parameters in the latter potential.

Effects of three-body interactions in the parametric and modulational instabilities of Bose–Einstein condensates

International Nuclear Information System (INIS)

Wamba, Etienne; Mohamadou, Alidou; Ekogo, Thierry B.; Atangana, Jacque; Kofane, Timoleon C.

2011-01-01

The parametric modulational instability for a discrete nonlinear Schrödinger equation with a cubic–quintic nonlinearity is analyzed. This model describes the dynamics of BECs, with both two- and three-body interatomic interactions trapped in an optical lattice. We identify and discuss the salient features of the three-body interaction in the parametric modulational instability. It is shown that the three-body interaction term can both, shift as well as narrow the window of parametric instability, and also change the behavior of a modulationally stable and parametrically unstable BEC with attractive two-body interaction. We explore this instability through the multiple-scale analysis and identify it numerically. The effect of the three body losses have also been investigated. -- Highlights: ► The parametric MI for the 1D GPE with a cubic–quintic nonlinearity is analyzed. ► The two- and three-body recombination and time-dependent scattering length is considered. ► We generate bright matter waves soliton through MI.

Oblique water entry of a three dimensional body

Directory of Open Access Journals (Sweden)

Scolan Yves-Marie

2014-12-01

Full Text Available The problem of the oblique water entry of a three dimensional body is considered. Wagner theory is the theoretical framework. Applications are discussed for an elliptic paraboloid entering an initially flat free surface. A dedicated experimental campaign yields a data base for comparisons. In the present analysis, pressure, force and dynamics of the wetted surface expansion are assessed.

Streamwise-body-force-model for rapid simulation combining internal and external flow fields

Directory of Open Access Journals (Sweden)

Cui Rong

2016-10-01

Full Text Available A streamwise-body-force-model (SBFM is developed and applied in the overall flow simulation for the distributed propulsion system, combining internal and external flow fields. In view of axial stage effects, fan or compressor effects could be simplified as body forces along the streamline. These body forces which are functions of local parameters could be added as source terms in Navier-Stokes equations to replace solid boundary conditions of blades and hubs. The validation of SBFM with uniform inlet and distortion inlet of compressors shows that pressure performance characteristics agree well with experimental data. A three-dimensional simulation of the integration configuration, via a blended wing body aircraft with a distributed propulsion system using the SBFM, has been completed. Lift coefficient and drag coefficient agree well with wind tunnel test results. Results show that to reach the goal of rapid integrated simulation combining internal and external flow fields, the computational fluid dynamics method based on SBFM is reasonable.

Three-axis optical force plate for studies in small animal locomotor mechanics

International Nuclear Information System (INIS)

Hsieh, S. Tonia

2006-01-01

The use of force plates to measure whole-body locomotor mechanics is a well-established technique. However, commercially available force plates are not sensitive enough for use on small-bodied vertebrates or invertebrates. The standard design for single- and multiple-axis, high-sensitivity force plates built by individual research groups uses semiconductor foil strain gauges to measure deflections; yet foil strain gauges are highly temperature and position sensitive, resulting in a drifting base line and nonlinear responses. I present here a design for a three-axis optical force plate that was successfully calibrated to measure forces as small as 1.5 mN and is capable of determining the position of center of pressure with a mean error of 0.07 cm along the X axis and 0.13 cm along the Y axis. Using optical sensors instead of foil strain gauges to measure deflection, this force plate is not subject to temperature-related drift and is more robust against slight positioning inaccuracies. This force plate was used to measure forces produced by amphibious fishes weighing less than 2 g as they jumped off the force platform

Three-body forces, relativistic effects, isobars, and pions in nuclear systems

International Nuclear Information System (INIS)

Wiringa, R.B.

1983-01-01

Conventional microscopic calculations in nuclear physics start from a nonrelativistic Hamiltonian. The many-body Schroedinger equation is then solved to obtain the ground state energy, wave function, and expectation values of other quantities of interest. Such a procedure gives a qualitative description of nuclear saturation properties, but it is now well established that the simple H is quantitatively inadequate. For example, the light nuclei are underbound with too large a charge radius, while nuclear matter is overbound at far too high a density. This note reviews recent studies that go beyond the simple H. These include 1) the introduction of three-nucleon potentials, 2) estimates of relativistic effects, 3) the introduction of isobar degrees of freedom in the two-body potential, and 4) probing the influence of pion degrees of freedom on nuclear systems

A wormlike chain model of forced desorption of a polymer adsorbed on an attractive wall

International Nuclear Information System (INIS)

Lam, Pui-Man; Zhen, Yi

2014-01-01

Forced desorption of a semiflexible polymer chain on a solid substrate is theoretically investigated. The pulling force versus displacement is studied for varying adsorption energy ε and persistence length P. It is found that the relationships between pulling force and cantilever displacement show a series of characteristic force spikes at different persistence lengths P. These force spikes become more pronounced but the average magnitude of this force decreases as P grows. Our results are of relevance to the forced desorption of DNA on an attractive wall in single-molecule pulling experiments. (paper)

Force-controlled adjustment of car body fixtures

OpenAIRE

Keller, Carsten

2014-01-01

Production technology in modern car body assembling is affected by highly automated and complex facilities. However, in mounting car body assemblies adjustments are always necessary to react on quality instabilities of the input parts. Today these adjustments are made according to experience and with a high content of manual operation. This paper describes an innovative method that detects part deformations in a force sensitive way following the works of Dr. Muck, who developed a force sensit...

Three-dimensional imaging of atomic four-body processes

CERN Document Server

Schulz, M; Fischer, D; Kollmus, H; Madison, D H; Jones, S; Ullrich, J

2003-01-01

To understand the physical processes that occur in nature we need to obtain a solid concept about the 'fundamental' forces acting between pairs of elementary particles. it is also necessary to describe the temporal and spatial evolution of many mutually interacting particles under the influence of these forces. This latter step, known as the few-body problem, remains an important unsolved problem in physics. Experiments involving atomic collisions represent a useful testing ground for studying the few-body problem. For the single ionization of a helium atom by charged particle impact, kinematically complete experiments have been performed since 1969. The theoretical analysis of such experiments was thought to yield a complete picture of the basic features of the collision process, at least for large collision energies. These conclusions are, however, almost exclusively based on studies of restricted electron-emission geometries. We report three- dimensional images of the complete electron emission pattern for...

High Cable Forces Deteriorate Pinch Force Control in Voluntary-Closing Body-Powered Prostheses.

Directory of Open Access Journals (Sweden)

Mona Hichert

Full Text Available It is generally asserted that reliable and intuitive control of upper-limb prostheses requires adequate feedback of prosthetic finger positions and pinch forces applied to objects. Body-powered prostheses (BPPs provide the user with direct proprioceptive feedback. Currently available BPPs often require high cable operation forces, which complicates control of the forces at the terminal device. The aim of this study is to quantify the influence of high cable forces on object manipulation with voluntary-closing prostheses.Able-bodied male subjects were fitted with a bypass-prosthesis with low and high cable force settings for the prehensor. Subjects were requested to grasp and transfer a collapsible object as fast as they could without dropping or breaking it. The object had a low and a high breaking force setting.Subjects conducted significantly more successful manipulations with the low cable force setting, both for the low (33% more and high (50% object's breaking force. The time to complete the task was not different between settings during successful manipulation trials.High cable forces lead to reduced pinch force control during object manipulation. This implies that low cable operation forces should be a key design requirement for voluntary-closing BPPs.

Analysis of Electromagnetic Attractive Force : Examination by Magnetic Circuit, Finite Element Method and Experiment

OpenAIRE

薮野, 浩司; 大和田, 竜太郎; 青島, 伸治; Hiroshi, YABUNO; Ryotaro, OOWADA; Nobuharu, AOSHIMA; 筑波大学; 筑波大学院; 筑波大学

1998-01-01

This paper presents the limitation of the magnetic circuit method. The force between magnetic bodies can be approximated accurately by the magnetic circuit method. Therefore this method has been used widely for the estimation of magnetic force. However this method is limited by the magnetic leakage and can be not used in the case when the gap between the magnetic bodies is wide. It is very important to clarify the limitation of the magnetic circuit method. In this research, the force of an el...

Solution of the Chandler-Gibson equations for a three-body test problem

International Nuclear Information System (INIS)

Gibson, A.G.; Waters, A.J.; Berthold, G.H.; Chandler, C.

1991-01-01

The Chandler-Gibson (CG) N-body equations are tested by considering the problem of three nonrelativistic particles moving on a line and interacting through attractive delta-function potentials. In particular, the input Born and overlap matrix-valued functions are evaluated analytically, and the CG equations are solved using a B-spline collocation method. The computed scattering matrix elements are within 0.5% of the known exact solutions, and the corresponding scattering probabilities are within 0.001% of the exact probabilities, both below and above the 3-body breakup threshold. These results establish that the CG method is practical, as well as theoretically correct, and may be a valuable approach for solving certain more complicated N-body scattering problems

Simulation of body force field effects on airfoil separation control and optimization of plasma actuator

International Nuclear Information System (INIS)

Abdoli, A; Mirzaee, I; Purmahmod, N; Anvari, A

2008-01-01

Among all active flow control methods, EHD, MHD and EMHD are the only methods which operate on the basis of body force induction on flow field. The EHD plasma actuator is the proper method which has been used in various flow control applications recently. In this paper, the effects of different body force fields on different domains have been studied for separation control on NACA 0021 and the results have been discussed. The airflow velocity has been assumed to be 35 m s -1 at a post-stall angle of attack of 23 deg. Three different domains have been used around the airfoil to investigate body forces with different strengths and directions and those which give the best result in separation control have been obtained for each domain. It has been shown that the results could be used for optimizing the plasma actuator by manipulating its electrode configuration. Two non-dimensional numbers, A b and D c , have been obtained and validated by different applied body forces. These numbers have been defined for plasma actuators to show their efficiency in different applications

The Putative Son's Attractiveness Alters the Perceived Attractiveness of the Putative Father.

Science.gov (United States)

Prokop, Pavol

2015-08-01

A body of literature has investigated female mate choice in the pre-mating context (pre-mating sexual selection). Humans, however, are long-living mammals forming pair-bonds which sequentially produce offspring. Post-mating evaluations of a partner's attractiveness may thus significantly influence the reproductive success of men and women. I tested herein the theory that the attractiveness of putative sons provides extra information about the genetic quality of fathers, thereby influencing fathers' attractiveness across three studies. As predicted, facially attractive boys were more frequently attributed to attractive putative fathers and vice versa (Study 1). Furthermore, priming with an attractive putative son increased the attractiveness of the putative father with the reverse being true for unattractive putative sons. When putative fathers were presented as stepfathers, the effect of the boy's attractiveness on the stepfather's attractiveness was lower and less consistent (Study 2). This suggests that the presence of an attractive boy has the strongest effect on the perceived attractiveness of putative fathers rather than on non-fathers. The generalized effect of priming with beautiful non-human objects also exists, but its effect is much weaker compared with the effects of putative biological sons (Study 3). Overall, this study highlighted the importance of post-mating sexual selection in humans and suggests that the heritable attractive traits of men are also evaluated by females after mating and/or may be used by females in mate poaching.

Gender differences in the evaluation of physical attractiveness ideals for male and female body builds.

Science.gov (United States)

Salusso-Deonier, C J; Markee, N L; Pedersen, E L

1993-06-01

The purposes of this research were (1) to explore gender differences in the evaluation of physical attractiveness stimuli developed to represent commonly occurring real builds, (2) to identify observers' concepts of physical attractiveness ideals promoted by the media, and (3) to begin cross-validation of these stimuli as representations of observers' concepts of ideal physical attractiveness for male and female builds. Responses included (1) open-ended descriptions of ideal male and ideal female build, (2) ratings of relative attractiveness of 12 male and 15 female stimuli, (3) selections of stimulus types which best represented ideal builds, and (4) selections of stimulus types perceived to be promoted by the media. Analysis showed strong cross-validation among modes of response. Ideal male build included average/balanced type (small and medium), lean/broad-shouldered type (large), and muscular bulk type (medium). Ideal female body build included average/balanced type (small and medium) and lean/broad-shouldered type (small and medium). Gender differences were in emphasis only. Women emphasized lean/broad-shouldered and average/balanced male types. Men emphasized the muscular bulk male type. Body types perceived to be media-promoted highlighted stereotypic male muscularity and female leanness.

Effect of attractive interactions between polymers on the effective force acting between colloids immersed in a polymer system: Analytic liquid-state theory.

Science.gov (United States)

Chervanyov, A I

2016-12-28

By making use of the polymer reference interaction site model, we analytically study the effect of attractive interactions between polymers on the effective forces acting between colloids immersed in a polymer system. The performed theoretical analysis has no restrictions with respect to the polymer density and relative sizes of the colloids and polymers. The polymer mediated (PM) potential acting between colloids is shown to significantly depend on the strength and range of the polymer-polymer interactions. In the nano-particle limit, where the colloid radius is much smaller than the polymer gyration radius, the presence of attractive polymer-polymer interactions causes only quantitative changes to the PM potential. In the opposite limit of relatively large colloids, the polymer-polymer interactions revert the sign of the total effective force acting between colloids so that this force becomes attractive at sufficiently large polymer densities. With the objective to study an intricate interplay between the attractive PM forces and steric repulsion in different polymer density regimes, we calculate the second virial coefficient B of the total effective potential acting between colloids. The dependence of B on the polymer density is discussed in detail, revealing several novel features of the PM interactions caused by the presence of attractive polymer-polymer interactions.

Attractive and Repulsive Forces on Particles in Oscillatory Flow

Science.gov (United States)

Agarwal, Siddhansh; Rallabandi, Bhargav; Raju, David; Thameem, Raqeeb; Hilgenfeldt, Sascha

2016-11-01

A large class of oscillating flows gives rise to rectified streaming motion of the fluid. It has recently been shown that particle transport in such flows, excited by bubbles oscillating at ultrasound frequencies, leads to differential displacement and efficient sorting of microparticles by size. We derive a general expression for the instantaneous radial force experienced by a small spherical particle in the vicinity of an oscillating interface, and generalize the radial projection of the Maxey-Riley equation to include this effect. Varying relevant system parameters, we show that the net effect on the particle can be either an attraction to or a repulsion from the bubble surface, depending in particular on the particle size and the particle/fluid density contrast. We demonstrate that these predictions are in agreement with a variety of experiments.

Density-dependent effective baryon–baryon interaction from chiral three-baryon forces

Energy Technology Data Exchange (ETDEWEB)

Petschauer, Stefan, E-mail: stefan.petschauer@ph.tum.de [Physik Department, Technische Universität München, D-85747 Garching (Germany); Haidenbauer, Johann [Institute for Advanced Simulation, Institut für Kernphysik and Jülich Center for Hadron Physics, Forschungszentrum Jülich, D-52425 Jülich (Germany); Kaiser, Norbert [Physik Department, Technische Universität München, D-85747 Garching (Germany); Meißner, Ulf-G. [Institute for Advanced Simulation, Institut für Kernphysik and Jülich Center for Hadron Physics, Forschungszentrum Jülich, D-52425 Jülich (Germany); Helmholtz-Institut für Strahlen- und Kernphysik, Universität Bonn, D-53115 Bonn (Germany); Bethe Center for Theoretical Physics, Universität Bonn, D-53115 Bonn (Germany); Weise, Wolfram [Physik Department, Technische Universität München, D-85747 Garching (Germany)

2017-01-15

A density-dependent effective potential for the baryon–baryon interaction in the presence of the (hyper)nuclear medium is constructed, based on the leading (irreducible) three-baryon forces derived within SU(3) chiral effective field theory. We evaluate the contributions from three classes: contact terms, one-pion exchange and two-pion exchange. In the strangeness-zero sector we recover the known result for the in-medium nucleon–nucleon interaction. Explicit expressions for the ΛN in-medium potential in (asymmetric) nuclear matter are presented. Our results are suitable for implementation into calculations of (hyper)nuclear matter. In order to estimate the low-energy constants of the leading three-baryon forces we introduce the decuplet baryons as explicit degrees of freedom and construct the relevant terms in the minimal non-relativistic Lagrangian. With these, the constants are estimated through decuplet saturation. Utilizing this approximation we provide numerical results for the effect of the three-body force in symmetric nuclear matter and pure neutron matter on the ΛN interaction. A moderate repulsion that increases with density is found in comparison to the free ΛN interaction.

Simulation of body force field effects on airfoil separation control and optimization of plasma actuator

Energy Technology Data Exchange (ETDEWEB)

Abdoli, A; Mirzaee, I; Purmahmod, N [Faculty of Engineering, Urmia University, Urmia (Iran, Islamic Republic of); Anvari, A [Department of Physics, Sharif University of Technology, Tehran (Iran, Islamic Republic of)], E-mail: ab.abdoli@gmail.com

2008-09-07

Among all active flow control methods, EHD, MHD and EMHD are the only methods which operate on the basis of body force induction on flow field. The EHD plasma actuator is the proper method which has been used in various flow control applications recently. In this paper, the effects of different body force fields on different domains have been studied for separation control on NACA 0021 and the results have been discussed. The airflow velocity has been assumed to be 35 m s{sup -1} at a post-stall angle of attack of 23 deg. Three different domains have been used around the airfoil to investigate body forces with different strengths and directions and those which give the best result in separation control have been obtained for each domain. It has been shown that the results could be used for optimizing the plasma actuator by manipulating its electrode configuration. Two non-dimensional numbers, A{sub b} and D{sub c}, have been obtained and validated by different applied body forces. These numbers have been defined for plasma actuators to show their efficiency in different applications.

Identification of Motive Forces on the Whole Body System during Walking

Directory of Open Access Journals (Sweden)

Raghdan J. AlKhoury

2010-01-01

Full Text Available Motive forces by muscles are applied to different parts of the human body in a periodic fashion when walking at a uniform rate. In this study, the whole human body is modeled as a multidegree of freedom (MDOF system with seven degrees of freedom. In view of the changing contact conditions with the ground due to alternating feet movements, the system under study is considered piecewise time invariant for each half-period when one foot is in contact with the ground. Forces transmitted from the body to the ground while walking at a normal pace are experimentally measured and numerically simulated. Fourth-order Runge-Kutta method is employed to numerically simulate the forces acting on different masses of the body. An optimization problem is formulated with the squared difference between the measured and simulated forces transmitted to the ground as the objective function, and the motive forces on the body masses as the design variables to solve.

Evaluating self and partner physical attractiveness.

Science.gov (United States)

Swami, Viren; Furnham, Adrian; Georgiades, Chrissa; Pang, Lily

2007-03-01

This study used a novel questionnaire to examine ratings of self and partner physical attractiveness. Seventy-two men and 83 women estimated their own and their opposite-sex partner's overall physical attractiveness and the attractiveness of various body parts and measures. They also answered six simple questions concerning physical attractiveness. Results showed significant gender differences in self-estimates of overall facial attractiveness and upper body features. In general, and regardless of gender, participants rated their opposite-sex partners as being significantly more attractive than themselves. In addition, the results showed that body weight and facial attractiveness were the best predictors of overall physical attractiveness. Implications of these results in terms of social biases are considered.

Patterns of subcutaneous fat deposition and the relationship between body mass index and waist-to-hip ratio: implications for models of physical attractiveness.

Science.gov (United States)

Cornelissen, Piers L; Toveé, Martin J; Bateson, Melissa

2009-02-07

Body mass index (BMI) and waist-to-hip ratio (WHR) are two widely used anthropometric indices of body shape argued to convey different information about health and fertility. Both indices have also been shown to affect attractiveness ratings of female bodies. However, BMI and WHR are naturally positively correlated, complicating studies designed to identify their relative importance in predicting health and attractiveness outcomes. We show that the correlation between BMI and WHR depends on the assumed model of subcutaneous fat deposition. An additive model, whereby fat is added to the waist and hips at a constant rate, predicts a correlation between BMI and WHR because with increasing fat, the difference between the waist and hips becomes smaller relative to total width. This model is supported by longitudinal and cross-sectional data. We parameterized the function relating WHR to BMI for white UK females of reproductive age, and used this function to statistically decompose body shape into two independent components. We show that judgements of the attractiveness of female bodies are well explained by the component of curvaceousness related to BMI but not by residual curvaceousness. Our findings resolve a long-standing dispute in the attractiveness literature by confirming that although WHR appears to be an important predictor of attractiveness, this is largely explained by the direct effect of total body fat on WHR, thus reinforcing the conclusion that total body fat is the primary determinant of female body shape attractiveness.

Coulomb-Sturmian separable expansion approach: Three-body Faddeev calculations for Coulomb-like interactions

International Nuclear Information System (INIS)

Papp, Z.; Plessas, W.

1996-01-01

We demonstrate the feasibility and efficiency of the Coulomb-Sturmian separable expansion method for generating accurate solutions of the Faddeev equations. Results obtained with this method are reported for several benchmark cases of bosonic and fermionic three-body systems. Correct bound-state results in agreement with the ones established in the literature are achieved for short-range interactions. We outline the formalism for the treatment of three-body Coulomb systems and present a bound-state calculation for a three-boson system interacting via Coulomb plus short-range forces. The corresponding result is in good agreement with the answer from a recent stochastic-variational-method calculation. copyright 1996 The American Physical Society

Radiation-reaction force on a small charged body to second order

Science.gov (United States)

Moxon, Jordan; Flanagan, Éanna

2018-05-01

In classical electrodynamics, an accelerating charged body emits radiation and experiences a corresponding radiation-reaction force, or self-force. We extend to higher order in the total charge a previous rigorous derivation of the electromagnetic self-force in flat spacetime by Gralla, Harte, and Wald. The method introduced by Gralla, Harte, and Wald computes the self-force from the Maxwell field equations and conservation of stress-energy in a limit where the charge, size, and mass of the body go to zero, and it does not require regularization of a singular self-field. For our higher-order computation, an adjustment of the definition of the mass of the body is necessary to avoid including self-energy from the electromagnetic field sourced by the body in the distant past. We derive the evolution equations for the mass, spin, and center-of-mass position of the body through second order. We derive, for the first time, the second-order acceleration dependence of the evolution of the spin (self-torque), as well as a mixing between the extended body effects and the acceleration-dependent effects on the overall body motion.

Quantum fictitious forces

DEFF Research Database (Denmark)

Bialynicki-Birula, I; Cirone, M.A.; Dahl, Jens Peder

2002-01-01

We present Heisenberg's equation of motion for the radial variable of a free non-relativistic particle in D dimensions. The resulting radial force consists of three contributions: (i) the quantum fictitious force which is either attractive or repulsive depending on the number of dimensions, (ii......) a singular quantum force located at the origin, and (iii) the centrifugal force associated with non-vanishing angular momentum. Moreover, we use Heisenberg's uncertainty relation to introduce a lower bound for the kinetic energy of an ensemble of neutral particles. This bound is quadratic in the number...... of atoms and can be traced back to the repulsive quantum fictitious potential. All three forces arise for a free particle: "Force without force"....

Novel insights into pericarp, protein body globoids of aleurone layer, starchy granules of three cereals gained using atomic force microscopy and environmental scanning electronic microscopy.

Science.gov (United States)

Antonini, Elena; Zara, Carolina; Valentini, Laura; Gobbi, Pietro; Ninfali, Paolino; Menotta, Michele

2018-02-05

In this study, we applied Environmental Scanning Electron Microscopy-Energy Dispersive Spectroscopy (ESEM-EDS) and Atomic Force Microscopy (AFM) analysis to three different cereal caryopses: barley, oat and einkorn wheat. The morphological structures, chemical elemental composition and surface characteristics of the three cereals were described. Regarding the morphology, barley showed the thickest pericarp, providing a strong barrier digestion and absorption of nutrients. The aleurone layer of each cereal type contained protein body globoids within its cells. Large type-A and small type-B starchy granules were revealed in the endosperm of barley and einkorn wheat, whereas irregular starchy granules were found in oats. The starchy granule elemental composition, detected by ESEM-EDS, was rather homogenous in the three cereals, whereas the pericarp and protein body globoids showed heterogeneity. In the protein body globoids, oats showed higher P and K concentrations than barley and einkorn wheat. Regarding the topographic profiles, detected by AFM, einkorn wheat starchy granules showed a surface profile that differed significantly from that of oats and barley, which were quite similar to one another. The present work provides insights into the morphological and chemical makeup of the three grains shedding light on the higher bio-accessibility of einkorn wheat nutrients compared to barley and oats, providing important suggestions for human nutrition and technological standpoints.

Novel insights into pericarp, protein body globoids of aleurone layer, starchy granules of three cereals gained using atomic force microscopy and environmental scanning electronic microscopy

Science.gov (United States)

Antonini, Elena; Zara, Carolina; Valentini, Laura; Gobbi, Pietro; Menotta, Michele

2018-01-01

In this study, we applied Environmental Scanning Electron Microscopy-Energy Dispersive Spectroscopy (ESEM-EDS) and Atomic Force Microscopy (AFM) analysis to three different cereal caryopses: barley, oat and einkorn wheat. The morphological structures, chemical elemental composition and surface characteristics of the three cereals were described. Regarding the morphology, barley showed the thickest pericarp, providing a strong barrier to digestion and absorption of nutrients. The aleurone layer of each cereal type contained protein body globoids within its cells. Large type-A and small type-B starchy granules were revealed in the endosperm of barley and einkorn wheat, whereas irregular starchy granules were found in oats. The starchy granule elemental composition, detected by ESEM-EDS, was rather homogenous in the three cereals, whereas the pericarp and protein body globoids showed heterogeneity. In the protein body globoids, oats showed higher P and K concentrations than barley and einkorn wheat. Regarding the topographic profiles, detected by AFM, einkorn wheat starchy granules showed a surface profile that differed significantly from that of oats and barley, which were quite similar to one another. The present work provides insights into the morphological and chemical makeup of the three grains shedding light on the higher bio-accessibility of einkorn wheat nutrients compared to barley and oats, providing important suggestions for human nutrition and technological standpoints. PMID:29569870

Three-body segment musculoskeletal model of the upper limb

Directory of Open Access Journals (Sweden)

Valdmanová L.

2013-06-01

Full Text Available The main aim is to create a computational three-body segment model of an upper limb of a human body for determination of muscle forces generated to keep a given loaded upper limb position. The model consists of three segments representing arm, forearm, hand and of all major muscles connected to the segments. Muscle origins and insertions determination corresponds to a real anatomy. Muscle behaviour is defined according to the Hill-type muscle model consisting of contractile and viscoelastic element. The upper limb is presented by a system of three rigid bars connected by rotational joints. The whole limb is fixed to the frame in the shoulder joint. A static balance problem is solved by principle of virtual work. The system of equation describing the musculoskeletal system is overdetermined because more muscles than necessary contribute to get the concrete upper limb position. Hence the mathematical problem is solved by an optimization method searching the least energetically-consuming solution. The upper limb computational model is verified by electromyography of the biceps brachii muscle.

Effect of Perturbations in Coriolis and Centrifugal Forces on the Nonlinear Stability of Equilibrium Point in Robe's Restricted Circular Three-Body Problem

Directory of Open Access Journals (Sweden)

P. P. Hallan

2008-01-01

Full Text Available The effect of perturbations in Coriolis and cetrifugal forces on the nonlinear stability of the equilibrium point of the Robe's (1977 restricted circular three-body problem has been studied when the density parameter K is zero. By applying Kolmogorov-Arnold-Moser (KAM theory, it has been found that the equilibrium point is stable for all mass ratios μ in the range of linear stability 8/9+(2/3((43/25ϵ1−(10/3ϵ<μ<1, where ϵ and ϵ1 are, respectively, the perturbations in Coriolis and centrifugal forces, except for five mass ratios μ1=0.93711086−1.12983217ϵ+1.50202694ϵ1, μ2 = 0.9672922−0.5542091ϵ+ 1.2443968ϵ1, μ3=0.9459503−0.70458206ϵ+ 1.28436549ϵ1, μ4=0.9660792−0.30152273ϵ + 1.11684064ϵ1, μ5=0.893981−2.37971679ϵ + 1.22385421ϵ1, where the theory is not applicable.

Female Facial Attractiveness Assessed from Three-Dimensional Contour Lines by University Students

Directory of Open Access Journals (Sweden)

Jinwara Jirathamopas

2018-05-01

Full Text Available Background: Three-dimensional (3D images could provide more accurate evaluation for facial attractiveness than two-dimensional (2D images. The 3D facial image could be simplified into gray scale 3D contour lines. Whether female facial attractiveness could be perceived in these simplified 3D facial contour lines should be determined. Methods: A series of 100 2D photographs (one frontal and two lateral views and 3D contour lines extracted from 3D facial images of females were projected onto a screen. Each image presentation lasted 5 s, and the evaluators marked their impression of each image’s facial attractiveness on a five-point Likert scale within 3 s of its presentation. The evaluation of the 3D contour lines was performed twice, 2 weeks apart. The evaluators were university students. Results: High consistency (r = 0.92 was found for the first and second evaluation of 3D facial contour lines for female facial attractiveness. The judgments of unattractive face were more consistent than the judgments of attractive face. Male students tended to give lower scores than female students in the evaluation of female facial attractiveness. Conclusions: Female facial attractiveness could be evaluated by 3D facial contour lines. 3D facial contour lines should be one of the key factors of facial attractiveness.

On the Evolution of Pulsatile Flow Subject to a Transverse Impulse Body Force

Science.gov (United States)

di Labbio, Giuseppe; Keshavarz-Motamed, Zahra; Kadem, Lyes

2014-11-01

In the event of an unexpected abrupt traffic stop or car accident, automotive passengers will experience an abrupt body deceleration. This may lead to tearing or dissection of the aortic wall known as Blunt Traumatic Aortic Rupture (BTAR). BTAR is the second leading cause of death in automotive accidents and, although quite frequent, the mechanisms leading to BTAR are still not clearly identified, particularly the contribution of the flow field. As such, this work is intended to provide a fundamental framework for the investigation of the flow contribution to BTAR. In this fundamental study, pulsatile flow in a three-dimensional, straight pipe of circular cross-section is subjected to a unidirectional, transverse, impulse body force applied on a strictly bounded volume of fluid. These models were simulated using the Computational Fluid Dynamics (CFD) software FLUENT. The evolution of fluid field characteristics was investigated during and after the application of the force. The application of the force significantly modified the flow field. The force induces a transverse pressure gradient causing the development of secondary flow structures that dissipate the energy added by the acceleration. Once the force ceases to act, these structures are carried downstream and gradually dissipate their excess energy.

Casimir-Polder forces on atoms in the presence of magnetoelectronic bodies

International Nuclear Information System (INIS)

Buhmann, S.Y.

2007-01-01

In this work, the CP force between a single neutral atom or molecule and neutral magnetoelectric bodies is studied. The focus lies on the pure vacuum CP force, i.e., the electromagnetic field is in general understood to be in its ground state. Furthermore, we assume that the atom-body separation is sufficiently large to ensure that the atom is adequately characterised as an electric dipole, while the body can be described by its macroscopic magnetoelectric properties; and that repulsive exchange forces due to the overlap between the electronic wave functions of the atom and the bodies can be neglected. Interactions due to non-vanishing net charges, permanent electric dipole moments, magnetisability, quadrupole (or higher multipole) polarisabilities of the atom and those resulting from non-local or anisotropic magnetoelectric properties of the bodies are ignored. (orig.)

Casimir-Polder forces on atoms in the presence of magnetoelectronic bodies

Energy Technology Data Exchange (ETDEWEB)

Buhmann, S Y

2007-07-05

In this work, the CP force between a single neutral atom or molecule and neutral magnetoelectric bodies is studied. The focus lies on the pure vacuum CP force, i.e., the electromagnetic field is in general understood to be in its ground state. Furthermore, we assume that the atom-body separation is sufficiently large to ensure that the atom is adequately characterised as an electric dipole, while the body can be described by its macroscopic magnetoelectric properties; and that repulsive exchange forces due to the overlap between the electronic wave functions of the atom and the bodies can be neglected. Interactions due to non-vanishing net charges, permanent electric dipole moments, magnetisability, quadrupole (or higher multipole) polarisabilities of the atom and those resulting from non-local or anisotropic magnetoelectric properties of the bodies are ignored. (orig.)

BMI not WHR modulates BOLD fMRI responses in a sub-cortical reward network when participants judge the attractiveness of human female bodies.

Directory of Open Access Journals (Sweden)

Ian E Holliday

Full Text Available In perceptual terms, the human body is a complex 3d shape which has to be interpreted by the observer to judge its attractiveness. Both body mass and shape have been suggested as strong predictors of female attractiveness. Normally body mass and shape co-vary, and it is difficult to differentiate their separate effects. A recent study suggested that altering body mass does not modulate activity in the reward mechanisms of the brain, but shape does. However, using computer generated female body-shaped greyscale images, based on a Principal Component Analysis of female bodies, we were able to construct images which covary with real female body mass (indexed with BMI and not with body shape (indexed with WHR, and vice versa. Twelve observers (6 male and 6 female rated these images for attractiveness during an fMRI study. The attractiveness ratings were correlated with changes in BMI and not WHR. Our primary fMRI results demonstrated that in addition to activation in higher visual areas (such as the extrastriate body area, changing BMI also modulated activity in the caudate nucleus, and other parts of the brain reward system. This shows that BMI, not WHR, modulates reward mechanisms in the brain and we infer that this may have important implications for judgements of ideal body size in eating disordered individuals.

Reply to ``Comment on `Attractive forces between ions in quantum plasmas: Failure of linearized quantum hydrodynamics' ''

Science.gov (United States)

Bonitz, M.; Pehlke, E.; Schoof, T.

2013-03-01

This is the last of a series of three papers. In the first [Phys. Rev. E10.1103/PhysRevE.87.033105 87, 033105 (2013)], the same authors presented a critical analysis of the prediction of “novel attractive forces” between protons in dense hydrogen put forward by Shukla and Eliasson in a recent Letter [Phys. Rev. Lett.10.1103/PhysRevLett.108.165007 108, 165007 (2012)]. Based on ab initio density functional theory (DFT) calculations and general considerations, it was shown that no such force exists. In the second of the three papers [Phys. Rev. E10.1103/PhysRevE.87.037101 87, 037101 (2013)], Shukla, Eliasson, and Akbari-Moghanjoughi (SEA) rejected this analysis. SEA did not discuss our arguments but claimed that the discrepancy between their quantum hydrodynamic model (QHD) and DFT is due to a failure of the latter. It is the purpose of the present Reply to demonstrate that this claim is incorrect because DFT is more accurate than QHD, by construction.

Robe's Restricted Problem of 2 + 2 Bodies with a Roche Ellipsoid - Triaxial System

Science.gov (United States)

Aggarwal, Rajiv; Kaur, Bhavneet; Yadav, Sushil

2018-03-01

This paper investigates the motion of two infinitesimal masses on the location and stability of the equilibrium points in Robe's restricted problem of 2 + 2 bodies with the bigger primary a Roche ellipsoid and the smaller a triaxial body. We suppose the bigger primary of mass m 1 to be filled with a homogeneous incompressible fluid of density ρ 1. The third and the fourth bodies (of mass m 3 and m 4 respectively) are small solid spheres of density ρ 3 and ρ 4 respectively inside the ellipsoid, with the assumption that the mass and the radius of the third and the fourth body are infinitesimal. We assume that m 2 is describing a circle around m 1. The masses m 3 and m 4 mutually attract each other, do not influence the motion of m 1 and m 2 but are influenced by them. We have taken into consideration all the three components of the pressure field in deriving the expression for the buoyancy force viz (i) due to the own gravitational field of the fluid (ii) that originating in the attraction of m 2 (iii) that arising from the centrifugal force. In this paper, equilibrium solutions of m 3 and m 4 and their linear stability are analyzed.

Three-axis force sensor with fiber Bragg grating.

Science.gov (United States)

Hyundo Choi; Yoan Lim; Junhyung Kim

2017-07-01

Haptic feedback is critical for many surgical tasks, and it replicates force reflections at the surgical site. To meet the force reflection requirements, we propose a force sensor with an optical fiber Bragg grating (FBG) for robotic surgery. The force sensor can calculate three directional forces of an instrument from the strain of three FBGs, even under electromagnetic interference. A flexible ring-shape structure connects an instrument tip and fiber strain gages to sense three directional force. And a stopper mechanism is added in the structure to avoid plastic deformation under unexpected large force on the instrument tip. The proposed sensor is experimentally verified to have a sensing range from -12 N to 12 N, and its sensitivity was less than 0.06 N.

Discussion on ‘Novel attractive force between ions in quantum plasmas—failure of simulations based on a density functional approach’

Science.gov (United States)

Shukla, P. K.; Eliasson, B.; Akbari-Moghanjoughi, M.

2013-01-01

In a paper on arXiv, Bonitz et al (2012 arXiv:1205.4922v1 [physics.plasm-ph]) (hereafter referred to as BPS) erroneously attributed the qualitative discrepancy between their density functional theory (DFT) simulation results with the analytical discovery of the Shukla-Eliasson (SE) attractive force which brings ions closer to the failure of the linearized quantum hydrodynamic theory. In this paper, we describe the underlying physics of the novel SE attractive force and its validity, as well as discuss some of the key features of the well-established quantum hydrodynamic theory and working mechanisms for DFT simulations, in addition to giving some critical notes on the falsified and misleading conclusions presented by BPS in their dubious paper. Furthermore, we also present a mass-density value for possible 4He metallic plasma lattice formation under the SE force.

Discussion on ‘Novel attractive force between ions in quantum plasmas - failure of simulations based on a density functional approach’

International Nuclear Information System (INIS)

Shukla, P K; Eliasson, B; Akbari-Moghanjoughi, M

2013-01-01

In a paper on arXiv, Bonitz et al (2012 arXiv:1205.4922v1 [physics.plasm-ph]) (hereafter referred to as BPS) erroneously attributed the qualitative discrepancy between their density functional theory (DFT) simulation results with the analytical discovery of the Shukla-Eliasson (SE) attractive force which brings ions closer to the failure of the linearized quantum hydrodynamic theory. In this paper, we describe the underlying physics of the novel SE attractive force and its validity, as well as discuss some of the key features of the well-established quantum hydrodynamic theory and working mechanisms for DFT simulations, in addition to giving some critical notes on the falsified and misleading conclusions presented by BPS in their dubious paper. Furthermore, we also present a mass-density value for possible 4 He metallic plasma lattice formation under the SE force.

Female appearance: facial and bodily attractiveness as shape

Directory of Open Access Journals (Sweden)

KATRIN SCHAEFER

2006-06-01

Full Text Available Human physical attractiveness is supposed to reflect developmental stability (i.e. the ability of individuals to maintain stable development of their morphology under a given environmental condition and physiological status. Hence, evolutionary psychologists have suggested that appearance may not only reveal so called ‘honest signals’ but even comprise a single ornament of mate value. However, it is still a matter of debate which physical features affect the ratings of female beauty, and whether these features are truly associated with aspects of developmental and physiological status. Here we present morphometric data of images of faces and bodies from 92 women together with ratings of attractiveness by 60 men. A total of 101 somatometric landmarks were digitized as two-dimensional coordinates from three views: facial, front and back full-body view. These image sets were analyzed separately by means of geometric morphometric methodology (GMM. Attractiveness ratings of the face and body were significantly associated with both (i the amount of fluctuating asymmetry (as a measure of developmental stability, and (ii specific localized shape differences in regions of known estrogen sensitivity. The results support the notion that ratings of women’s physical attractiveness are indeed based on indicators of developmental stability and physiological status.

Δ-excitations and the three-nucleon force

International Nuclear Information System (INIS)

Epelbaum, E.; Krebs, H.; Meissner, Ulf-G.

2008-01-01

We study the three-nucleon force in chiral effective field theory with explicit Δ-resonance degrees of freedom. We show that up to next-to-next-to-leading order, the only contribution to the isospin symmetric three-nucleon force involving the spin-3/2 degrees of freedom is given by the two-pion-exchange diagram with an intermediate delta, frequently called the Fujita-Miyazawa force. We also analyze the leading isospin-breaking corrections due to the delta. For that, we give the first quantitative analysis of the delta quartet mass splittings in chiral effective field theory including the leading electromagnetic corrections. The charge-symmetry breaking three-nucleon force due to an intermediate delta excitation is small, of the order of a few keV

Effects of repulsive three-body force in 12C + 12C scattering at 100A MeV

Directory of Open Access Journals (Sweden)

W.W. Qu

2015-12-01

Full Text Available The angular distribution of 12C + 12C scattering at an incident energy of 100A MeV has been measured. The elastic and inelastic scatterings in 12C to the excitation energies of up to ∼45 MeV were measured simultaneously for the first time with the high-resolution Grand Raiden spectrometer at the Research Center for Nuclear Physics (RCNP. The angular distributions of the elastic scattering to the ground state (01+ and inelastic scattering to the 4.44 MeV (21+ excited state were precisely obtained in the angular range of 1.0°–7.5° with a step of 0.1°. Additionally, the angular distribution was obtained for the sum of the cross sections for excitation energies above the 4.44 MeV state up to 11 MeV, which includes the 7.65 MeV (02+, 9.64 MeV (31−, and 10.30 MeV (22+ states, in addition to probably the simultaneous excitation of the 4.44 MeV state in the projectile and the target nuclei. Those combined data provide a means to study the effects of channel coupling on the elastic cross section. The observed angular distributions are compared with theoretical calculations based on three double-folding models with complex G-matrix interactions, the CEG07b, MPa, and ESC models. The importance of three-body repulsive forces included in the CEG07b and MPa models will be discussed.

The gravitational attraction algorithm: a new metaheuristic applied to a nuclear reactor core design optimization problem

International Nuclear Information System (INIS)

Sacco, Wagner F.; Oliveira, Cassiano R.E. de

2005-01-01

A new metaheuristic called 'Gravitational Attraction Algorithm' (GAA) is introduced in this article. It is an analogy with the gravitational force field, where a body attracts another proportionally to both masses and inversely to their distances. The GAA is a populational algorithm where, first of all, the solutions are clustered using the Fuzzy Clustering Means (FCM) algorithm. Following that, the gravitational forces of the individuals in relation to each cluster are evaluated and this individual or solution is displaced to the cluster with the greatest attractive force. Once it is inside this cluster, the solution receives small stochastic variations, performing a local exploration. Then the solutions are crossed over and the process starts all over again. The parameters required by the GAA are the 'diversity factor', which is used to create a random diversity in a fashion similar to genetic algorithm's mutation, and the number of clusters for the FCM. GAA is applied to the reactor core design optimization problem which consists in adjusting several reactor cell parameters in order to minimize the average peak-factor in a 3-enrichment-zone reactor, considering operational restrictions. This problem was previously attacked using the canonical genetic algorithm (GA) and a Niching Genetic Algorithm (NGA). The new metaheuristic is then compared to those two algorithms. The three algorithms are submitted to the same computational effort and GAA reaches the best results, showing its potential for other applications in the nuclear engineering field as, for instance, the nuclear core reload optimization problem. (author)

Numerical simulation of flows in a circular pipe transversely subjected to a localized impulsive body force with applications to blunt traumatic aortic rupture

Energy Technology Data Exchange (ETDEWEB)

Labbio, G Di; Keshavarz-Motamed, Z; Kadem, L, E-mail: lcfd@encs.concordia.ca [Department of Mechanical and Industrial Engineering, Concordia University, Montreal, Quebec, H3G 1M8 (Canada)

2017-06-15

Much debate surrounds the mechanisms responsible for the occurrence of blunt traumatic aortic rupture in car accidents, particularly on the role of the inertial body force experienced by the blood due to the abrupt deceleration. The isolated influence of such body forces acting on even simple fluid flows is a fundamental problem in fluid dynamics that has not been thoroughly investigated. This study numerically investigates the fundamental physical problem, where the pulsatile flow in a straight circular pipe is subjected to a transverse body force on a localized volume of fluid. The body force is applied as a brief rectangular impulse in three distinct cases, namely during the accelerating, peak, and decelerating phases of the pulsatile flow. A dimensionless number, termed the degree of influence of the body force (Ψ), is devised to quantify the relative strength of the body force over the flow inertia. The impact induces counter-rotating cross-stream vortices at the boundaries of the forced section accompanied by complex secondary flow structures. This secondary flow is found to develop slowest for an impact occurring during an accelerating flow and fastest during a decelerating flow. The peak skewness of the velocity field, however, occurred at successively later times for the three respective cases. After the impact, these secondary flows act to restore the unforced state and such dominant spatial structures are revealed by proper orthogonal decomposition of the velocity field. This work presents a new class of problems that requires further theoretical and experimental investigation. (paper)

Numerical simulation of flows in a circular pipe transversely subjected to a localized impulsive body force with applications to blunt traumatic aortic rupture

Science.gov (United States)

Di Labbio, G.; Keshavarz-Motamed, Z.; Kadem, L.

2017-06-01

Much debate surrounds the mechanisms responsible for the occurrence of blunt traumatic aortic rupture in car accidents, particularly on the role of the inertial body force experienced by the blood due to the abrupt deceleration. The isolated influence of such body forces acting on even simple fluid flows is a fundamental problem in fluid dynamics that has not been thoroughly investigated. This study numerically investigates the fundamental physical problem, where the pulsatile flow in a straight circular pipe is subjected to a transverse body force on a localized volume of fluid. The body force is applied as a brief rectangular impulse in three distinct cases, namely during the accelerating, peak, and decelerating phases of the pulsatile flow. A dimensionless number, termed the degree of influence of the body force (Ψ), is devised to quantify the relative strength of the body force over the flow inertia. The impact induces counter-rotating cross-stream vortices at the boundaries of the forced section accompanied by complex secondary flow structures. This secondary flow is found to develop slowest for an impact occurring during an accelerating flow and fastest during a decelerating flow. The peak skewness of the velocity field, however, occurred at successively later times for the three respective cases. After the impact, these secondary flows act to restore the unforced state and such dominant spatial structures are revealed by proper orthogonal decomposition of the velocity field. This work presents a new class of problems that requires further theoretical and experimental investigation.

Threshold separation distance for attractive interaction between dust particles

International Nuclear Information System (INIS)

Jabdaraghi, R. Najafi; Sobhanian, S.

2008-01-01

Interaction between dust grains in a dusty plasma could be both repulsive and attractive. The Coulomb interaction between two negatively charged dust particulates and the electrostatic force between them are repulsive, while the shadowing force affecting them is attractive. We show in this paper that in some experimental conditions, there is some grain separation zone for which the attractive shadowing force is larger than the repulsive forces between them. In experimental conditions, for the grains separation distance r = 0.4 cm the shadowing force is almost equal to the electrostatic force between them and for r>0.4 cm the shadowing force exceeds the electrostatic force. So the resultant interaction force will be attractive. The possibility of dust crystal formation in this zone and also the motion of dust particles in the resultant potential of the form V = -(a/r)+(b/r 2 ) will be discussed. This form of potential comes from the combination electrostatic (F es (c/r 3 )) and shadowing (F shadow = -(d/r 2 )) forces.

New results on order and spacing of levels for two- and three-body systems

International Nuclear Information System (INIS)

Grosse, H.; Martin, A.; Richard, J.M.; Taxil, P.

1987-01-01

The authors propose sufficient conditions on the potential binding a two-body system to compare; the energy of a state with angular momentum iota+1 to the average of the energies of the neighbouring states with angular momentum iota, the spacings of the successive iota = O excitations. Applications to quarkonium physics are given. The authors also find a condition giving the sign of the parameter Δ controlling the pattern of levels obtained by perturbing the lowest positive parity excitation of a three-body system bound by harmonic oscillator two body forces

Three-body forces mandated by Poincare invariance

International Nuclear Information System (INIS)

Coester, F.

1986-01-01

Poincare invariant models for the three-nucleon system are examined which have the same heuristic relation to field theories as the nonrelativistic nuclear models. The generators of the infinitesimal dynamical transformations can be obtained as functions of the kinematic generators, the invariant mass operator of the interacting system, and additional operators. These additional operators are the components of the Newton-Wigner position operator in the instant form, and the transverse components of the spin in the front form. The relativistic dynamics of Poincare transformations is examined, and then these concepts are applied to two-nucleon systems. The transition to a fully interacting three-nucleon system is made

Adolescent Perceptions of Body Weight and Attractiveness: Important Issues in Alcohol and Illicit Drug Use?

Science.gov (United States)

Page, Randy M.; And Others

1995-01-01

Examined relationship between adolescent self-perception of body weight and physical attractiveness and the use of alcohol and drugs in high school students (n=1,915). In general, adolescents dissatisfied with their appearance used illicit substances and got drunk more often than those satisfied with their appearance. (SNR)

Many body effects in the van der Waals force

International Nuclear Information System (INIS)

Perez, P.; Claro, F.

1985-08-01

A classical model of fluctuating dipoles is proposed for the evaluation of many-body effects in the van der Waals force between neutral polarizable particles. The method is applied to solid xenon giving the correct low temperature stable structure, unlike the usual two-body potential result. (author)

Analysis of the Competitive Environment of Tourist Destinations Aiming at Attracting FDI by Applying Porter's Five Forces Model

OpenAIRE

Dobrivojević, Gordana

2013-01-01

Aims: The aim of this article is to come to the conclusion whether Porter’s five forces model can be adjusted for the purpose of assessing competitive environment of the tourist destination, in order to attract Tourism Foreign Direct Investments (TFDI), and use it as such as an alternative method for comprehension and enhancement of competitive advantage. Study design: Research paper. Methodology: The research relies on the well-known Porter’s five forces, which the author adjusted and applie...

The three-body problem

CERN Document Server

Marchal, Christian

1990-01-01

Recent research on the theory of perturbations, the analytical approach and the quantitative analysis of the three-body problem have reached a high degree of perfection. The use of electronics has aided developments in quantitative analysis and has helped to disclose the extreme complexity of the set of solutions. This accelerated progress has given new orientation and impetus to the qualitative analysis that is so complementary to the quantitative analysis. The book begins with the various formulations of the three-body problem, the main classical results and the important questions and conje

Institutional Image Indicators of Three Universities: Basis for Attracting Prospective Entrants

Science.gov (United States)

Bringula, Rex P.; Basa, Roselle S.

2011-01-01

This study determined the student profile and enrollment of the three Universities in the University Belt. It also found out the respondents' level of consideration concerning the institutional image indicators that served as basis for attracting prospective entrants. Descriptive statistics revealed the following: most of the respondents belonged…

Big two personality and big three mate preferences: similarity attracts, but country-level mate preferences crucially matter.

Science.gov (United States)

Gebauer, Jochen E; Leary, Mark R; Neberich, Wiebke

2012-12-01

People differ regarding their "Big Three" mate preferences of attractiveness, status, and interpersonal warmth. We explain these differences by linking them to the "Big Two" personality dimensions of agency/competence and communion/warmth. The similarity-attracts hypothesis predicts that people high in agency prefer attractiveness and status in mates, whereas those high in communion prefer warmth. However, these effects may be moderated by agentics' tendency to contrast from ambient culture, and communals' tendency to assimilate to ambient culture. Attending to such agentic-cultural-contrast and communal-cultural-assimilation crucially qualifies the similarity-attracts hypothesis. Data from 187,957 online-daters across 11 countries supported this model for each of the Big Three. For example, agentics-more so than communals-preferred attractiveness, but this similarity-attracts effect virtually vanished in attractiveness-valuing countries. This research may reconcile inconsistencies in the literature while utilizing nonhypothetical and consequential mate preference reports that, for the first time, were directly linked to mate choice.

Simulation of shear thickening in attractive colloidal suspensions.

Science.gov (United States)

Pednekar, Sidhant; Chun, Jaehun; Morris, Jeffrey F

2017-03-01

The influence of attractive forces between particles under conditions of large particle volume fraction, ϕ, is addressed using numerical simulations which account for hydrodynamic, Brownian, conservative and frictional contact forces. The focus is on conditions for which a significant increase in the apparent viscosity at small shear rates, and possibly the development of a yield stress, is observed. The high shear rate behavior for Brownian suspensions has been shown in recent work [R. Mari, R. Seto, J. F. Morris and M. M. Denn PNAS, 2015, 112, 15326-15330] to be captured by the inclusion of pairwise forces of two forms, one a contact frictional interaction and the second a repulsive force often found in stabilized colloidal dispersions. Under such conditions, shear thickening is observed when shear stress is comparable to the sum of the Brownian stress, kT/a 3 , and a characteristic stress based on the combination of interparticle force, i.e. σ ∼ F 0 /a 2 with kT the thermal energy, F 0 the repulsive force scale and a the particle radius. At sufficiently large ϕ, this shear thickening can be very abrupt. Here it is shown that when attractive interactions are present with the noted forces, the shear thickening is obscured, as the viscosity shear thins with increasing shear rate, eventually descending from an infinite value (yield stress conditions) to a plateau at large stress; this plateau is at the same level as the large-shear rate viscosity found in the shear thickened state without attractive forces. It is shown that this behavior is consistent with prior observations in shear thickening suspensions modified to be attractive through depletion flocculation [V. Gopalakrishnan and C. F. Zukoski J. Rheol., 2004, 48, 1321-1344]. The contributions of the contact, attractive, and hydrodynamics forces to the bulk stress are presented, as are the contact networks found at different attractive strengths.

Statistical methods for including two-body forces in large system calculations

International Nuclear Information System (INIS)

Grimes, S.M.

1980-07-01

Large systems of interacting particles are often treated by assuming that the effect on any one particle of the remaining N-1 may be approximated by an average potential. This approach reduces the problem to that of finding the bound-state solutions for a particle in a potential; statistical mechanics is then used to obtain the properties of the many-body system. In some physical systems this approach may not be acceptable, because the two-body force component cannot be treated in this one-body limit. A technique for incorporating two-body forces in such calculations in a more realistic fashion is described. 1 figure

Universality in low energy three-body systems

International Nuclear Information System (INIS)

Amorim, A.E.A.; Tomio, L; Frederico, T.

1997-01-01

The renormalizability of the quantum theory of non-relativistic three-body system with zero range interaction, warranties that all the low-energy three-body properties are well defined and the low-energy two-body and only one three-body physical information are known. Considering this observation, we have shown that the conditions for the occurrence of Efimov states can be easily reached with any model of short range potential where the three-body ground state and the corresponding binding energy of the subsystems are kept fixed. This approach was applied to the recently discovered halo nuclei. (author)

Universal Three-Body Physics in Ultracold KRb Mixtures

DEFF Research Database (Denmark)

Wacker, L. J.; Jørgensen, N. B.; Birkmose, Danny Matthiesen

2016-01-01

Ultracold atomic gases have recently become a driving force in few-body physics due to the observation of the Efimov effect. While initially observed in equal mass systems, one expects even richer few-body physics in the mass-imbalanced case. In previous experiments with ultracold mixtures of pot...

Three-body interactions in many-body effective field theory

International Nuclear Information System (INIS)

Furnstahl, R.J.

2004-01-01

This contribution is an advertisement for applying effective field theory (EFT) to many-body problems, including nuclei and cold atomic gases. Examples involving three-body interactions are used to illustrate how EFT's quantify and systematically eliminate model dependence, and how they make many-body calculations simpler and more powerful

Accelerator-feasible N-body nonlinear integrable system

Directory of Open Access Journals (Sweden)

V. Danilov

2014-12-01

Full Text Available Nonlinear N-body integrable Hamiltonian systems, where N is an arbitrary number, have attracted the attention of mathematical physicists for the last several decades, following the discovery of some number of these systems. This paper presents a new integrable system, which can be realized in facilities such as particle accelerators. This feature makes it more attractive than many of the previous such systems with singular or unphysical forces.

Nonlinear gravitational self-force: Field outside a small body

Science.gov (United States)

Pound, Adam

2012-10-01

A small extended body moving through an external spacetime gαβ creates a metric perturbation hαβ, which forces the body away from geodesic motion in gαβ. The foundations of this effect, called the gravitational self-force, are now well established, but concrete results have mostly been limited to linear order. Accurately modeling the dynamics of compact binaries requires proceeding to nonlinear orders. To that end, I show how to obtain the metric perturbation outside the body at all orders in a class of generalized wave gauges. In a small buffer region surrounding the body, the form of the perturbation can be found analytically as an expansion for small distances r from a representative worldline. Given only a specification of the body’s multipole moments, the field obtained in the buffer region suffices to find the metric everywhere outside the body via a numerical puncture scheme. Following this procedure at first and second order, I calculate the field in the buffer region around an arbitrarily structured compact body at sufficiently high order in r to numerically implement a second-order puncture scheme, including effects of the body’s spin. I also define nth-order (local) generalizations of the Detweiler-Whiting singular and regular fields and show that in a certain sense, the body can be viewed as a skeleton of multipole moments.

The d-α elastic scattering and the lithium-6 in a three-body model with separable interactions

International Nuclear Information System (INIS)

Charnomordic, Brigitte.

1976-01-01

This work consists in a three-body treatment of the six nucleon system. The model is constructed by considering two identical nucleons and a structureless alpha particle. Such a system can be described by the Faddeev-Lovelace equations. A partial antisymetrization is performed taking into account the identity of the nucleons. Pairwise interacting particles with nonlocal separable forces are introduced. Two-body potentials are chosen in each n-n and n-α partial wave. After an analysis of the existing separable interactions, new n-α and 1S0 parametrization are constructed. The sensitivity to the tensor force and the role of the N-α description are especially studied. The case of d-α elastic scattering is also discussed. The observables: differential cross-section, analyzing powers and transfer polarization coefficients are calculated and compared with experiments. The results show the ability of a three-body model with separable interactions in describing the main properties of the d-α elastic scattering and lithium-6 [fr

Three-body unitarity with isobars revisited

Energy Technology Data Exchange (ETDEWEB)

Mai, M.; Hu, B. [The George Washington University, Washington, DC (United States); Doering, M. [The George Washington University, Washington, DC (United States); Thomas Jefferson National Accelerator Facility, Newport News, VA (United States); Pilloni, A. [Thomas Jefferson National Accelerator Facility, Newport News, VA (United States); Szczepaniak, A. [Thomas Jefferson National Accelerator Facility, Newport News, VA (United States); Indiana University, Center for Exploration of Energy and Matter, Bloomington, IN (United States); Indiana University, Physics Department, Bloomington, IN (United States)

2017-09-15

The particle exchange model of hadron interactions can be used to describe three-body scattering under the isobar assumption. In this study we start from the 3 → 3 scattering amplitude for spinless particles, which contains an isobar-spectator scattering amplitude. Using a Bethe-Salpeter Ansatz for the latter, we derive a relativistic three-dimensional scattering equation that manifestly fulfills three-body unitarity and two-body unitarity for the sub-amplitudes. This property holds for energies above breakup and also in the presence of resonances in the sub-amplitudes. (orig.)

Sources of spurious force oscillations from an immersed boundary method for moving-body problems

Science.gov (United States)

Lee, Jongho; Kim, Jungwoo; Choi, Haecheon; Yang, Kyung-Soo

2011-04-01

When a discrete-forcing immersed boundary method is applied to moving-body problems, it produces spurious force oscillations on a solid body. In the present study, we identify two sources of these force oscillations. One source is from the spatial discontinuity in the pressure across the immersed boundary when a grid point located inside a solid body becomes that of fluid with a body motion. The addition of mass source/sink together with momentum forcing proposed by Kim et al. [J. Kim, D. Kim, H. Choi, An immersed-boundary finite volume method for simulations of flow in complex geometries, Journal of Computational Physics 171 (2001) 132-150] reduces the spurious force oscillations by alleviating this pressure discontinuity. The other source is from the temporal discontinuity in the velocity at the grid points where fluid becomes solid with a body motion. The magnitude of velocity discontinuity decreases with decreasing the grid spacing near the immersed boundary. Four moving-body problems are simulated by varying the grid spacing at a fixed computational time step and at a constant CFL number, respectively. It is found that the spurious force oscillations decrease with decreasing the grid spacing and increasing the computational time step size, but they depend more on the grid spacing than on the computational time step size.

Analytical thermodynamics of a strongly attractive three-component Fermi gas in one dimension

International Nuclear Information System (INIS)

He Peng; Yin Xiangguo; Wang Yupeng; Guan Xiwen; Batchelor, Murray T.

2010-01-01

Ultracold three-component atomic Fermi gases in one dimension are expected to exhibit rich physics due to the presence of trions and different pairing states. Quantum phase transitions from the trion state into a paired phase and a normal Fermi liquid occur at zero temperature. We derive the analytical thermodynamics of strongly attractive three-component one-dimensional fermions with SU(3) symmetry via the thermodynamic Bethe ansatz method in unequal Zeeman splitting fields H 1 and H 2 . We find explicitly that for low temperature the system acts like either a two-component or a three-component Tomonaga-Luttinger liquid dependent on the system parameters. The phase diagrams for the chemical potential and specific heat are presented for illustrative values of the Zeeman splitting. We also demonstrate that crossover between different Tomonaga-Luttinger-liquid phases exhibit singular behavior in specific heat and entropy as the temperature tends to zero. Beyond Tomonaga-Luttinger-liquid physics, we obtain the equation of state which provides a precise description of universal thermodynamics and quantum criticality in three-component, strongly attractive Fermi gases.

Dynamics of a particle attracted by a magnetized wire

International Nuclear Information System (INIS)

Lawson, W.F. Jr.; Simons, W.H.; Treat, R.P.

1977-01-01

The dynamics of a particle attracted by a magnetized wire is studied for nonvanishing gravitational forces and a broad range of Stokes number K. The Newtonian equation of motion for the particle is integrated for 10 -2 2 , a range which includes conditions where the particle inertia cannot be ignored. Families of trajectories, typical of low and high K, reveal the dominance of viscous forces at low K, as expected, and show oscillatory approach to capture for high K, where inertia is significant. Capture distances in the interval 1< or =X/sub c/< or =8 are given as a function of three independent dimensionless parameters which measure the strengths of the magnetic, viscous, and gravitational forces. The range of conditions is established for which it is permissible to neglect, for the purpose of computing capture distances, both the inertia and the radially attractive short-range part of the magnetic force. The equation of motion in which the inertia and the short-range term are neglected is studied. An integral of this equation is found which extends the trajectory equations of Zebel and Luborsky to include the gravitational force. A general approach to the construction of the integral of motion shows how to find the trajectory equation for a particle moving in a more complicated incompressible viscous flow with higher multipole contributions to the magnetic field of force

Laws of attraction: from perceptual forces to conceptual similarity.

Science.gov (United States)

Ziemkiewicz, Caroline; Kosara, Robert

2010-01-01

Many of the pressing questions in information visualization deal with how exactly a user reads a collection of visual marks as information about relationships between entities. Previous research has suggested that people see parts of a visualization as objects, and may metaphorically interpret apparent physical relationships between these objects as suggestive of data relationships. We explored this hypothesis in detail in a series of user experiments. Inspired by the concept of implied dynamics in psychology, we first studied whether perceived gravity acting on a mark in a scatterplot can lead to errors in a participant's recall of the mark's position. The results of this study suggested that such position errors exist, but may be more strongly influenced by attraction between marks. We hypothesized that such apparent attraction may be influenced by elements used to suggest relationship between objects, such as connecting lines, grouping elements, and visual similarity. We further studied what visual elements are most likely to cause this attraction effect, and whether the elements that best predicted attraction errors were also those which suggested conceptual relationships most strongly. Our findings show a correlation between attraction errors and intuitions about relatedness, pointing towards a possible mechanism by which the perception of visual marks becomes an interpretation of data relationships.

Force direction patterns promote whole body stability even in hip-flexed walking, but not upper body stability in human upright walking

Science.gov (United States)

Müller, Roy; Rode, Christian; Aminiaghdam, Soran; Vielemeyer, Johanna; Blickhan, Reinhard

2017-11-01

Directing the ground reaction forces to a focal point above the centre of mass of the whole body promotes whole body stability in human and animal gaits similar to a physical pendulum. Here we show that this is the case in human hip-flexed walking as well. For all upper body orientations (upright, 25°, 50°, maximum), the focal point was well above the centre of mass of the whole body, suggesting its general relevance for walking. Deviations of the forces' lines of action from the focal point increased with upper body inclination from 25 to 43 mm root mean square deviation (RMSD). With respect to the upper body in upright gait, the resulting force also passed near a focal point (17 mm RMSD between the net forces' lines of action and focal point), but this point was 18 cm below its centre of mass. While this behaviour mimics an unstable inverted pendulum, it leads to resulting torques of alternating sign in accordance with periodic upper body motion and probably provides for low metabolic cost of upright gait by keeping hip torques small. Stabilization of the upper body is a consequence of other mechanisms, e.g. hip reflexes or muscle preflexes.

The shape of beauty: determinants of female physical attractiveness.

Science.gov (United States)

Fisher, Maryanne L; Voracek, Martin

2006-06-01

Rarely has one research area gained as much attention as that which is observed for female physical attractiveness. The past decade has resulted in numerous, exciting developments, particularly with respect to three proposed determinants of beauty: waist to hip ratio (WHR), body mass index (BMI), and curvaceousness. The goal of our paper is to provide a highly necessary review of contemporary research on the female attractiveness, including an in-depth examination of these factors. In our review, we first discuss WHR, an index of fat deposition, which is calculated by measuring the circumference of the waist compared to the circumference of the hips. WHR is controlled by the sex hormones, and increases as women age, and hence, may influence perceptions of attractiveness. This factor has been hotly contested, as some researchers have claimed that a WHR of approximately 0.7 is universally most attractive, whereas others have found inconsistent findings, or suggest the importance of other factors, such as BMI. Body mass index (BMI), calculated by dividing the body weight (in kilograms) by height (in meters) squared, serves as a measure of body fat. Although WHR and BMI are correlated, they lead to different conclusions, and the importance of BMI as a measure of female attractiveness is debated in the literature. Similar to WHR research, BMI and its role in attractiveness is not cross-culturally consistent and is affected by the availability of resources within a given environment. It may be the case that both WHR and BMI influence female attractiveness. However, there has been little investigation of this possibility. We have explored this issue in our research, which revealed that both influence attractiveness, but in addition, we noticed that curvaceousness was also a factor. Curvaceousness is the degree of "hourglass" shape as determined, for example, by the size of the bust, relative to the circumference of the hips and waist, and the size of the buttocks. However

Hyperspherical functions and quantum-mechanical three-body problem with application to carbon 12

International Nuclear Information System (INIS)

Letz, H.

1975-01-01

In this work a system of three identical particles (bosons) interacting by a particular two-body force is discussed. Using the complete set of the hyperspherical functions (K-harmonics), analytical expressions for eigenvalues and wave functions of the stationary states are found. The numerical evaluation gives a level sequence for a definite pair of potential parameters similar to that of the nucleus carbon 12

Dependence of inhomogeneous vibrational linewidth broadening on attractive forces from local liquid number densities

International Nuclear Information System (INIS)

George, S.M.; Harris, C.B.

1982-01-01

The dependence of inhomogeneous vibrational linewidth broadening on attractive forces form slowly varying local liquid number densities is examined. The recently developed Schweizer--Chandler theory of vibrational dephasing is used to compute absolute inhomogeneous broadening linewidths. The computed linewidths are compared to measured inhomogeneous broadening linewidths determined using picosecond vibrational dephasing experiments. There is a similarity between correlations of the Schweizer--Chandler and George--Auweter--Harris predicted inhomogeneous broadening linewidths and the measured inhomogeneous broadening linewidths. For the methyl stretches under investigation, this correspondence suggests that the width of the number density distribution in the liquid determines the relative inhomogeneous broadening magnitudes

Two-body and three-body correlations in Os-shell nuclei

International Nuclear Information System (INIS)

Halderson, D.W.

1974-01-01

It is well known that conventional Brueckner calculations with modern nucleon-nucleon potentials have failed to reproduce experimental saturation properties of finite nuclei. The intent was to determine whether the discrepancies are due to the methods of calculation or the nucleon-nucleon potentials. Brueckner procedures which include only two-body correlations were applied to Os-shell nuclei. Calculations were performed with and without the Hartree-Fock condition, with and without partial occupation probabilities, and with various propagators and Pauli correction techniques. Then the entire class of three-body correlations was calculated by matrix solution of the Bethe-Faddeev equations. The convergence necessary to validate this technique was achieved by constructing a set of basic functions which contain no center of mass excitations and yet are still properly antisymmetrized. The two-body calculations yielded typical Brueckner results. The nuclei were underbound or the radii were too small. However, the three-body calculations yielded reasonable radii and moderate overbinding for the Reid soft core and Hamada-Johnston potentials. Therefore, the Bethe-Faddeev formalism has been shown to be a reasonable approach to calculation of the three-body correlations in finite nuclei; and the results of []these calculations demonstrate that the underbinding and collapsed radii of two-body calculations were largely due to the uncalculated correlations. (auth)

Poroelastic theory of consolidation in unsaturated soils incorporating gravitational body forces

Science.gov (United States)

Lo, Wei-Cheng; Chao, Nan-Chieh; Chen, Chu-Hui; Lee, Jhe-Wei

2017-08-01

The generalization of the poroelasticity theory of consolidation in unsaturated soils to well represent gravitational body forces is presented in the current study. Three partial differential equations featuring the displacement vector of the solid phase, along with the excess pore water and air pressures as dependent variables are derived, with coupling that occurs in the first-order temporal- and spatial- derivative terms. The former arises from viscous drag between solid and fluid, whereas the latter is attributed to the presence of gravity. Given the physically-consistent initial and boundary conditions, these coupled equations are numerically solved under uniaxial strain as a representative example. Our results reveal that variations in the excess pore water pressure due to the existence of gravitational forces increase with soil depth, but these variations are not significant if the soil layer is not sufficiently long. A dimensionless parameter is defined theoretically to quantify the impact of those forces on the final total settlement. This impact is shown to become greater as the soil layer is less stiff and has more length, and bears an inversely-proportional trend with initial water saturation.

Separating the effects of repulsive and attractive forces on the phase diagram, interfacial, and critical properties of simple fluids.

Science.gov (United States)

Fuentes-Herrera, M; Moreno-Razo, J A; Guzmán, O; López-Lemus, J; Ibarra-Tandi, B

2016-06-07

Molecular simulations in the canonical and isothermal-isobaric ensembles were performed to study the effect of varying the shape of the intermolecular potential on the phase diagram, critical, and interfacial properties of model fluids. The molecular interactions were modeled by the Approximate Non-Conformal (ANC) theory potentials. Unlike the Lennard-Jones or Morse potentials, the ANC interactions incorporate parameters (called softnesses) that modulate the steepness of the potential in their repulsive and attractive parts independently. This feature allowed us to separate unambiguously the role of each region of the potential on setting the thermophysical properties. In particular, we found positive linear correlation between all critical coordinates and the attractive and repulsive softness, except for the critical density and the attractive softness which are negatively correlated. Moreover, we found that the physical properties related to phase coexistence (such as span of the liquid phase between the critical and triple points, variations in the P-T vaporization curve, interface width, and surface tension) are more sensitive to changes in the attractive softness than to the repulsive one. Understanding the different roles of attractive and repulsive forces on phase coexistence may contribute to developing more accurate models of liquids and their mixtures.

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...

Investigation of a cuboidal permanent magnet’s force exerted on a robotic capsule

Directory of Open Access Journals (Sweden)

Yang W

2014-08-01

Full Text Available Wan’an Yang,1 Chengbing Tang,2 Fengqing Qin1 1School of Computer and Information Engineering, Yibin University, Yibin, 2CNPC Chuanqing Geophysical Prospecting Company Research Center Computer Department, Chengdu, Sichuan, People’s Republic of China Abstract: To control and drive a robotic capsule accurately from outside a patient’s body, we present a schema in which the capsule enclosing the imaging device, circuits, batteries, etc is looped by a permanent magnet ring that acts as an actuator. A cuboidal permanent magnet situated outside the patient's body attracts or pushes the magnet ring from different directions to make the capsule move or rotate. A mathematic model of attractive or repulsive force that the cuboidal magnet exerts on the magnet ring is presented for accurate calculation of force. The experiments showed that the measuring force was in agreement with the theoretical one, and the relations between the dimensions of the cuboidal magnet and force are useful to produce a cuboidal magnet with optimal shape to get appropriate force. Keywords: control and drive, robotic capsule, permanent magnet ring, optimal dimension, force model

Interactions between internal forces, body stiffness, and fluid environment in a neuromechanical model of lamprey swimming.

Science.gov (United States)

Tytell, Eric D; Hsu, Chia-Yu; Williams, Thelma L; Cohen, Avis H; Fauci, Lisa J

2010-11-16

Animal movements result from a complex balance of many different forces. Muscles produce force to move the body; the body has inertial, elastic, and damping properties that may aid or oppose the muscle force; and the environment produces reaction forces back on the body. The actual motion is an emergent property of these interactions. To examine the roles of body stiffness, muscle activation, and fluid environment for swimming animals, a computational model of a lamprey was developed. The model uses an immersed boundary framework that fully couples the Navier-Stokes equations of fluid dynamics with an actuated, elastic body model. This is the first model at a Reynolds number appropriate for a swimming fish that captures the complete fluid-structure interaction, in which the body deforms according to both internal muscular forces and external fluid forces. Results indicate that identical muscle activation patterns can produce different kinematics depending on body stiffness, and the optimal value of stiffness for maximum acceleration is different from that for maximum steady swimming speed. Additionally, negative muscle work, observed in many fishes, emerges at higher tail beat frequencies without sensory input and may contribute to energy efficiency. Swimming fishes that can tune their body stiffness by appropriately timed muscle contractions may therefore be able to optimize the passive dynamics of their bodies to maximize peak acceleration or swimming speed.

The three body problem with energy dependent potentials

International Nuclear Information System (INIS)

Kim, Y.E.; McKay, C.M.; McKellar, B.H.J.

1975-10-01

It is shown how to generalize the three body equations of Faddeev, and of Karlsson and Zeiger, to include the case when the two body potential is energy dependent. Such generalizations will prove useful in the three nucleon problem and in three body models of nuclear reactions. (author)

Forced-Air Warming Provides Better Control of Body Temperature in Porcine Surgical Patients

Directory of Open Access Journals (Sweden)

Brian T. Dent

2016-09-01

Full Text Available Background: Maintaining normothermia during porcine surgery is critical in ensuring subject welfare and recovery, reducing the risk of immune system compromise and surgical-site infection that can result from hypothermia. In humans, various methods of patient heating have been demonstrated to be useful, but less evaluation has been performed in techniques to prevent hypothermia perioperatively in pigs. Methods: We compared body temperature regulation during surgery before and after modification of the ambient temperature of the operating laboratories. Three different methods of heating were then compared; a standard circulating water mattress, a resistive fabric blanket, and a forced hot air system. The primary measure was percentage of temperature readings outside a specification range of 36.7–40.0 °C. Results: Tighter control of the ambient temperature while using a circulating water mattress reduced the occurrence of out-of-specification body temperature readings from 20.8% to 5.0%, with most of these the result of hypothermia. Use of a resistive fabric blanket further reduced out-of-specification readings to 1.5%, with a slight increase in the occurrence of hyperthermia. Use of a forced air system reduced out-of-specification readings to less 0.1%. Conclusions: Maintenance of normothermia perioperatively in pig can be improved by tightly controlling ambient temperatures. Use of a resistive blanket or a forced air system can lead to better control than a circulating water mattress, with the forced air system providing a faster response to temperature variations and less chance of hyperthermia.

HUNGARIAN EXPERIENCES WITH THE BELIEFS ABOUT ATTRACTIVENESS SCALE.

Science.gov (United States)

Czeglédi, Edit; Szabo, Kornélia

2016-03-30

Sociocultural influences regarding bodily appearance and their psychological consequences play a considerable role in the development and maintenance of body image disturbance and eating disorders. The purpose of the study was to explore the psychometric properties of the Beliefs About Attractiveness Scale-Revised and its correlates among young adults in Hungary. In our cross-sectional online study, participants were 18-35 years old (N = 820, 40% male). self-reported anthropometric data, Beliefs About Attractiveness Scale-Revised, Eating Disorder Inventory, SCOFF questionnaire, Sociocultural Attitudes Towards Appearance Questionnaire-3, and Rosenberg Self-esteem Scale. The exploratory factor analysis showed that the fit indices of the three-factor solution are acceptable (χ²(₁₇₁)) = 5124.8, p scales were confirmed. Among those who were at risk of developing an eating disorder, all of the measured beliefs were significantly greater than among those who were not at risk (thin: Z = 6.501, p Scale-Revised is a reliable, valid measure and we suggest its introduction into Hungarian research. Relationships between beliefs about attractiveness and self- esteem, body image and eating disorders suggest intervention opportunities in with regards to prevention and treatment of eating disorders.

Heritability of attractiveness to mosquitoes.

Directory of Open Access Journals (Sweden)

G Mandela Fernández-Grandon

Full Text Available Female mosquitoes display preferences for certain individuals over others, which is determined by differences in volatile chemicals produced by the human body and detected by mosquitoes. Body odour can be controlled genetically but the existence of a genetic basis for differential attraction to insects has never been formally demonstrated. This study investigated heritability of attractiveness to mosquitoes by evaluating the response of Aedes aegypti (=Stegomyia aegypti mosquitoes to odours from the hands of identical and non-identical twins in a dual-choice assay. Volatiles from individuals in an identical twin pair showed a high correlation in attractiveness to mosquitoes, while non-identical twin pairs showed a significantly lower correlation. Overall, there was a strong narrow-sense heritability of 0.62 (SE 0.124 for relative attraction and 0.67 (0.354 for flight activity based on the average of ten measurements. The results demonstrate an underlying genetic component detectable by mosquitoes through olfaction. Understanding the genetic basis for attractiveness could create a more informed approach to repellent development.

Canonical three-body angular basis

International Nuclear Information System (INIS)

Matveenko, A.V.

2001-01-01

Three-body problems are basic for the quantum mechanics of molecular, atomic, or nuclear systems. We demonstrate that their variational solution for rotational states can be greatly simplified. A special choice of coordinates (hyperspherical) and of the kinematics (body-fixed coordinate frame) allows one to choose basis functions in a form that makes the angular coupling trivial. (author)

Estimation of Vertical Ground Reaction Forces and Sagittal Knee Kinematics During Running Using Three Inertial Sensors

Directory of Open Access Journals (Sweden)

Frank J. Wouda

2018-03-01

Full Text Available Analysis of running mechanics has traditionally been limited to a gait laboratory using either force plates or an instrumented treadmill in combination with a full-body optical motion capture system. With the introduction of inertial motion capture systems, it becomes possible to measure kinematics in any environment. However, kinetic information could not be provided with such technology. Furthermore, numerous body-worn sensors are required for a full-body motion analysis. The aim of this study is to examine the validity of a method to estimate sagittal knee joint angles and vertical ground reaction forces during running using an ambulatory minimal body-worn sensor setup. Two concatenated artificial neural networks were trained (using data from eight healthy subjects to estimate the kinematics and kinetics of the runners. The first artificial neural network maps the information (orientation and acceleration of three inertial sensors (placed at the lower legs and pelvis to lower-body joint angles. The estimated joint angles in combination with measured vertical accelerations are input to a second artificial neural network that estimates vertical ground reaction forces. To validate our approach, estimated joint angles were compared to both inertial and optical references, while kinetic output was compared to measured vertical ground reaction forces from an instrumented treadmill. Performance was evaluated using two scenarios: training and evaluating on a single subject and training on multiple subjects and evaluating on a different subject. The estimated kinematics and kinetics of most subjects show excellent agreement (ρ>0.99 with the reference, for single subject training. Knee flexion/extension angles are estimated with a mean RMSE <5°. Ground reaction forces are estimated with a mean RMSE < 0.27 BW. Additionaly, peak vertical ground reaction force, loading rate and maximal knee flexion during stance were compared, however, no significant

Approximate Coulomb effects in the three-body scattering problem

International Nuclear Information System (INIS)

Haftel, M.I.; Zankel, H.

1981-01-01

From the momentum space Faddeev equations we derive approximate expressions which describe the Coulomb-nuclear interference in the three-body elastic scattering, rearrangement, and breakup problems and apply the formalism to p-d elastic scattering. The approximations treat the Coulomb interference as mainly a two-body effect, but we allow for the charge distribution of the deuteron in the p-d calculations. Real and imaginary parts of the Coulomb correction to the elastic scattering phase shifts are described in terms of on-shell quantities only. In the case of pure Coulomb breakup we recover the distorted-wave Born approximation result. Comparing the derived approximation with the full Faddeev p-d elastic scattering calculation, which includes the Coulomb force, we obtain good qualitative agreement in S and P waves, but disagreement in repulsive higher partial waves. The on-shell approximation investigated is found to be superior to other current approximations. The calculated differential cross sections at 10 MeV raise the question of whether there is a significant Coulomb-nuclear interference at backward angles

Evaluating and improving the performance of thin film force sensors within body and device interfaces.

Science.gov (United States)

Likitlersuang, Jirapat; Leineweber, Matthew J; Andrysek, Jan

2017-10-01

Thin film force sensors are commonly used within biomechanical systems, and at the interface of the human body and medical and non-medical devices. However, limited information is available about their performance in such applications. The aims of this study were to evaluate and determine ways to improve the performance of thin film (FlexiForce) sensors at the body/device interface. Using a custom apparatus designed to load the sensors under simulated body/device conditions, two aspects were explored relating to sensor calibration and application. The findings revealed accuracy errors of 23.3±17.6% for force measurements at the body/device interface with conventional techniques of sensor calibration and application. Applying a thin rigid disc between the sensor and human body and calibrating the sensor using compliant surfaces was found to substantially reduce measurement errors to 2.9±2.0%. The use of alternative calibration and application procedures is recommended to gain acceptable measurement performance from thin film force sensors in body/device applications. Copyright © 2017 IPEM. Published by Elsevier Ltd. All rights reserved.

Equilibria of the three-body problem with rigid dumb-bell satellite

International Nuclear Information System (INIS)

Elipe, A.; Palacios, M.; Pretka-Ziomek, H.

2008-01-01

This paper is concerned with the orbital-rotational motion of an asymmetric dumb-bell (two masses with fixed distance among them) under the attraction of a central body. For this model, we find some equilibria and give sufficient conditions for their stability

Development of Swimming Human Simulation Model Considering Rigid Body Dynamics and Unsteady Fluid Force for Whole Body

Science.gov (United States)

Nakashima, Motomu; Satou, Ken; Miura, Yasufumi

The purpose of this study is to develop a swimming human simulation model considering rigid body dynamics and unsteady fluid force for the whole body, which will be utilized to analyze various dynamical problems in human swimming. First, the modeling methods and their formulations for the human body and the fluid force are respectively described. Second, experiments to identify the coefficients of the normal drag and the added mass are conducted by use of an experimental setup, in which a limb model rotates in the water, and its rotating angle and the bending moment at the root are measured. As the result of the identification, the present model for the fluid force was found to have satisfactory performance in order to represent the unsteady fluctuations of the experimental data, although it has 10% error. Third, a simulation for the gliding position is conducted in order to identify the tangential drag coefficient. Finally, a simulation example of standard six beat front crawl swimming is shown. The swimming speed of the simulation became a reasonable value, indicating the validity of the present simulation model, although it is 7.5% lower than the actual swimming.

Attractiveness Is Multimodal: Beauty Is Also in the Nose and Ear of the Beholder

Directory of Open Access Journals (Sweden)

Agata Groyecka

2017-05-01

Full Text Available Attractiveness plays a central role in human non-verbal communication and has been broadly examined in diverse subfields of contemporary psychology. Researchers have garnered compelling evidence in support of the evolutionary functions of physical attractiveness and its role in our daily lives, while at the same time, having largely ignored the significant contribution of non-visual modalities and the relationships among them. Acoustic and olfactory cues can, separately or in combination, strongly influence the perceived attractiveness of an individual and therefore attitudes and actions toward that person. Here, we discuss the relative importance of visual, auditory and olfactory traits in judgments of attractiveness, and review neural and behavioral studies that support the highly complex and multimodal nature of person perception. Further, we discuss three alternative evolutionary hypotheses aimed at explaining the function of multiple indices of attractiveness. In this review, we provide several lines of evidence supporting the importance of the voice, body odor, and facial and body appearance in the perception of attractiveness and mate preferences, and therefore the critical need to incorporate cross-modal perception and multisensory integration into future research on human physical attractiveness.

Attractiveness Is Multimodal: Beauty Is Also in the Nose and Ear of the Beholder.

Science.gov (United States)

Groyecka, Agata; Pisanski, Katarzyna; Sorokowska, Agnieszka; Havlíček, Jan; Karwowski, Maciej; Puts, David; Roberts, S Craig; Sorokowski, Piotr

2017-01-01

Attractiveness plays a central role in human non-verbal communication and has been broadly examined in diverse subfields of contemporary psychology. Researchers have garnered compelling evidence in support of the evolutionary functions of physical attractiveness and its role in our daily lives, while at the same time, having largely ignored the significant contribution of non-visual modalities and the relationships among them. Acoustic and olfactory cues can, separately or in combination, strongly influence the perceived attractiveness of an individual and therefore attitudes and actions toward that person. Here, we discuss the relative importance of visual, auditory and olfactory traits in judgments of attractiveness, and review neural and behavioral studies that support the highly complex and multimodal nature of person perception. Further, we discuss three alternative evolutionary hypotheses aimed at explaining the function of multiple indices of attractiveness. In this review, we provide several lines of evidence supporting the importance of the voice, body odor, and facial and body appearance in the perception of attractiveness and mate preferences, and therefore the critical need to incorporate cross-modal perception and multisensory integration into future research on human physical attractiveness.

Three-body approach to the nucleon-nucleus optical potential

International Nuclear Information System (INIS)

Tandy, P.C.; Redish, E.F.; Bolle, D.

1976-01-01

In the Watson single scattering theory of the optical potential it is customary to approximate the propagation by two-body Green functions in order to simplify calculations. The reaction mechanism being described, however, is decidedly three-body in character. The central difficulty in building three-body models for nucleon-nucleus elastic scattering is to find the proper way of imbedding the superposed three-body reaction mechanism in the many-body problem without introducing serious overcounting effects. One would also like an explicit description of the intermediate state processes responsible for absorption. In this paper a three-body approximation to the optical potential theory is presented which overcomes the overcounting problem and is capable of including the following effects: (1) the proper kinematics of the struck nucleon, (2) its binding potential, (3) the identity of target nucleons, and (4) realistic wave functions and spectroscopic factors. The three-body model for the optical potential can be extended using unitarity methods to yield a unified three-body-like model of elastic scattering, pickup, and single nucleon knockout. (Auth.)

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

Directory of Open Access Journals (Sweden)

Anton Schlechter

2014-11-01

attractiveness of the three. Gender, race and age did not have statistically significant main effects on job attractiveness. Practical/managerial implications: High levels of remuneration, benefits and variable payshould be incorporated and emphasised in organisational talent attraction strategies as theyare attractive for knowledge workers. If organisations want to attract prospective talentthey need to offer high levels of remuneration to make their offers appealing and attractive.Variable pay and benefits are, further, not sufficient to mitigate a low remuneration offer. Contribution: This study adds to the body of social science research as few studieshave empirically demonstrated a causal link between financial reward elements and jobattractiveness within a controlled laboratory environment. There is also limited empiricalresearch in South Africa that highlights the level and combinations of financial rewardelements that are attractive for talented knowledge employees.

Scattering Length Scaling Laws for Ultracold Three-Body Collisions

International Nuclear Information System (INIS)

D'Incao, J.P.; Esry, B.D.

2005-01-01

We present a simple and unifying picture that provides the energy and scattering length dependence for all inelastic three-body collision rates in the ultracold regime for three-body systems with short-range two-body interactions. Here, we present the scaling laws for vibrational relaxation, three-body recombination, and collision-induced dissociation for systems that support s-wave two-body collisions. These systems include three identical bosons, two identical bosons, and two identical fermions. Our approach reproduces all previous results, predicts several others, and gives the general form of the scaling laws in all cases

Gay male attraction toward muscular men: does mating context matter?

Science.gov (United States)

Varangis, Eleanna; Lanzieri, Nicholas; Hildebrandt, Tom; Feldman, Matthew

2012-03-01

The purpose of this study was to examine gay men's perceived attractiveness of male figures based on short-term and long-term partner contexts. A sample of 190 gay adult men rated the attractiveness of line-drawings depicting male figures varying systematically in muscularity and body fat percentage in both short-term and long-term dating contexts. Mixed effects modeling was used to estimate the effects of figure (muscularity and body fat), dating context (short-term vs. long-term), and individual rater characteristics on attractiveness ratings. Results indicated that figure muscularity and body-fat had significant non-linear (i.e., quadratic) relationships with attractiveness ratings, and short-term dating context was associated with more discriminating ratings of attractiveness. Interactions between individual characteristics and figure characteristics indicated that the more available the individual and lower body fat, the more discriminating they were in ratings of attractiveness. The implications for future investigations considering both object and observer characteristics of attractiveness preferences are discussed. Copyright © 2012 Elsevier Ltd. All rights reserved.

Dynamics of Three-Body Correlations in Quenched Unitary Bose Gases

Science.gov (United States)

Colussi, V. E.; Corson, J. P.; D'Incao, J. P.

2018-03-01

We investigate dynamical three-body correlations in the Bose gas during the earliest stages of evolution after a quench to the unitary regime. The development of few-body correlations is theoretically observed by determining the two- and three-body contacts. We find that the growth of three-body correlations is gradual compared to two-body correlations. The three-body contact oscillates coherently, and we identify this as a signature of Efimov trimers. We show that the growth of three-body correlations depends nontrivially on parameters derived from both the density and Efimov physics. These results demonstrate the violation of scaling invariance of unitary bosonic systems via the appearance of log-periodic modulation of three-body correlations.

Own Attractiveness and Dissatisfaction With Physical Appearance Independently Predict the Salience of Facial Cues to Size When Women Judge Other Women's Attractiveness.

Science.gov (United States)

Watkins, Christopher D

2017-11-01

While facial cues to body size are a valid guide to health and attractiveness, it is unclear whether the observer's own condition predicts the salience of (low) size as a cue to female attractiveness. The current study examines whether measures related to women's own attractiveness/appearance predict the extent to which they use facial cues to size to differentiate other women on the attractiveness dimension. Women completed a body mass index (BMI) preference task, where they indicated their preference for high- versus low-BMI versions of the same woman, provided data to calculate their BMI and completed various psychometric measures (self-rated attractiveness/health, dissatisfaction with physical appearance). Here, attractive women and women who were dissatisfied with their own appearance were more likely to associate facial cues to low body size with high attractiveness. These data suggest that psychological factors related to women's appearance shape their evaluations of other women based on cues to size. Such variation in attractiveness judgements may function to reduce the costs of female competition for resources, for example, by identifying "quality" rivals or excluding others based on cues to size.

Spin Modes in Nuclei and Nuclear Forces

International Nuclear Information System (INIS)

Suzuki, Toshio; Otsuka, Takaharu

2011-01-01

Spin modes in stable and unstable exotic nuclei are studied and important roles of tensor and three-body forces on nuclear structure are discussed. New shell model Hamiltonians, which have proper tensor components, are shown to explain shell evolutions toward drip-lines and spin properties of both stable and exotic nuclei, for example, Gamow-Teller transitions in 12 C and 14 C and an anomalous M1 transition in 17 C. The importance and the necessity of the repulsive monopole corrections in isospin T = 1 channel to the microscopic two-body interactions are pointed out. The corrections are shown to lead to the proper shell evolutions in neutron-rich isotopes. The three-body force, in particular the Fujita-Miyazawa force induced by Δ excitations, is pointed out to be responsible for the repulsive corrections among the valence neutrons. The important roles of the three-body force on the energies and transitions in exotic oxygen and calcium isotopes are demonstrated.

Investigation of Body Force Effects on Flow Boiling Critical Heat Flux

Science.gov (United States)

Zhang, Hui; Mudawar, Issam; Hasan, Mohammad M.

2002-01-01

The bubble coalescence and interfacial instabilities that are important to modeling critical heat flux (CHF) in reduced-gravity systems can be sensitive to even minute body forces. Understanding these complex phenomena is vital to the design and safe implementation of two-phase thermal management loops proposed for space and planetary-based thermal systems. While reduced gravity conditions cannot be accurately simulated in 1g ground-based experiments, such experiments can help isolate the effects of the various forces (body force, surface tension force and inertia) which influence flow boiling CHF. In this project, the effects of the component of body force perpendicular to a heated wall were examined by conducting 1g flow boiling experiments at different orientations. FC-72 liquid was boiled along one wall of a transparent rectangular flow channel that permitted photographic study of the vapor-liquid interface at conditions approaching CHF. High-speed video imaging was employed to capture dominant CHF mechanisms. Six different CHF regimes were identified: Wavy Vapor Layer, Pool Boiling, Stratification, Vapor Counterflow, Vapor Stagnation, and Separated Concurrent Vapor Flow. CHF showed great sensitivity to orientation for flow velocities below 0.2 m/s, where very small CHF values where measured, especially with downflow and downward-facing heated wall orientations. High flow velocities dampened the effects of orientation considerably. Figure I shows representative images for the different CHF regimes. The Wavy Vapor Layer regime was dominant for all high velocities and most orientations, while all other regimes were encountered at low velocities, in the downflow and/or downward-facing heated wall orientations. The Interfacial Lift-off model was modified to predict the effects of orientation on CHF for the dominant Wavy Vapor Layer regime. The photographic study captured a fairly continuous wavy vapor layer travelling along the heated wall while permitting liquid

A cluster expansion for bound three-alpha particles as a three-body problem

International Nuclear Information System (INIS)

Osman, A.

1981-08-01

A three-body model is proposed to study the nuclear bound states. The nucleus is described as a bound state of three clusters. A cluster expansion is introduced for the three cluster bound state problem. The present integral equations are treated by simple approximate solutions, which lead to effective potentials by using the present cluster expansion. The 12 C nucleus is described as a three-alpha particle bound state. The binding energy of 12 C is calculated numerically using the present cluster expansion as bound three-alpha clusters. The present three-body cluster expansion calculations are very near to the exact three-body calculations using separable potentials. The present theoretical calculations are in good agreement with the experimental measurements. (author)

Generalized separable expansion method of the two-body and the three-body scattering amplitudes

International Nuclear Information System (INIS)

Oryu, S.; Ishihara, T.

1976-01-01

A systematic method is proposed for obtaining new N-rank separable amplitudes of the two-body and the three-body equations. First of all, the authors start from the Amado equation which is modified from the three-body Faddeev equation by using the two-body Yamaguchi potential for the nucleon-nucleon interaction. It is well known that the Amado equation can be integrated on the real axis because the kernel has a logarithmic cut on the real axis. However, a separable three-body form factor which is regular on the real axis except for the cut has been found. (Auth.)

Three-body calculation of Be double- hypernuclei

Indian Academy of Sciences (India)

an intermediate sigma; and hyperon–nucleon–nucleon forces that may be relatively more important than three-nucleon forces, depending on whether sigmas are kept explicitly. So far, several cluster models have been proposed to estimate the ground-state bind- ing energies of double- species [1–6]. Recently,.

A Three-Axis Force Sensor for Dual Finger Haptic Interfaces

OpenAIRE

Fontana, Marco; Marcheschi, Simone; Salsedo, Fabio; Bergamasco, Massimo

2012-01-01

In this work we present the design process, the characterization and testing of a novel three-axis mechanical force sensor. This sensor is optimized for use in closed-loop force control of haptic devices with three degrees of freedom. In particular the sensor has been conceived for integration with a dual finger haptic interface that aims at simulating forces that occur during grasping and surface exploration. The sensing spring structure has been purposely designed in order to match force an...

Relativistic Descriptions of Few-Body Systems

International Nuclear Information System (INIS)

Karmanov, V. A.

2011-01-01

A brief review of relativistic effects in few-body systems, of theoretical approaches, recent developments and applications is given. Manifestations of relativistic effects in the binding energies, in the electromagnetic form factors and in three-body observables are demonstrated. The three-body forces of relativistic origin are also discussed. We conclude that relativistic effects in nuclei can be important in spite of small binding energy. At high momenta they clearly manifest themselves and are necessary to describe the deuteron e.m. form factors. At the same time, there is still a discrepancy in three-body observables which might be a result of less clarity in understanding the corresponding relativistic effects, the relativistic NN kernel and the three-body forces. Relativistic few-body physics remains to be a field of very intensive and fruitful researches. (author)

Poincaré and the three body problem

CERN Document Server

Barrow-Green, June

1997-01-01

The idea of chaos figures prominently in mathematics today. It arose in the work of one of the greatest mathematicians of the late 19th century, Henri Poincaré, on a problem in celestial mechanics: the three body problem. This ancient problem-to describe the paths of three bodies in mutual gravitational interaction-is one of those which is simple to pose but impossible to solve precisely. Poincaré's famous memoir on the three body problem arose from his entry in the competition celebrating the 60th birthday of King Oscar of Sweden and Norway. His essay won the prize and was set up in print as a paper in Acta Mathematica when it was found to contain a deep and critical error. In correcting this error Poincaré discovered mathematical chaos, as is now clear from Barrow-Green's pioneering study of a copy of the original memoir annotated by Poincaré himself, recently discovered in the Institut Mittag-Leffler in Stockholm. Poincaré and the Three Body Problem opens with a discussion of the development of the th...

"A Thing of Beauty Is a Joy Forever"? Returns to Physical Attractiveness over the Life Course

Science.gov (United States)

Jaeger, Mads Meier

2011-01-01

This article analyzes the effect of three aspects of physical attractiveness (facial attractiveness, Body Mass Index and height) on socio-economic and marital success over the life course. In a sample of high school graduates from Wisconsin followed from their late teens and until their mid-60s, I find that (1. taller men have higher earnings than…

SPH for impact force and ricochet behavior of water-entry bodies

Science.gov (United States)

Omidvar, Pourya; Farghadani, Omid; Nikeghbali, Pooyan

The numerical modeling of fluid interaction with a bouncing body has many applications in scientific and engineering application. In this paper, the problem of water impact of a body on free-surface is investigated, where the fixed ghost boundary condition is added to the open source code SPHysics2D1 to rectify the oscillations in pressure distributions with the repulsive boundary condition. First, after introducing the methodology of SPH and the option of boundary conditions, the still water problem is simulated using two types of boundary conditions. It is shown that the fixed ghost boundary condition gives a better result for a hydrostatics pressure. Then, the dam-break problem, which is a bench mark test case in SPH, is simulated and compared with available data. In order to show the behavior of the hydrostatics forces on bodies, a fix/floating cylinder is placed on free surface looking carefully at the force and heaving profile. Finally, the impact of a body on free-surface is successfully simulated for different impact angles and velocities.

Extended random-phase approximation with three-body ground-state correlations

International Nuclear Information System (INIS)

Tohyama, M.; Schuck, P.

2008-01-01

An extended random-phase approximation (ERPA) which contains the effects of ground-state correlations up to a three-body level is applied to an extended Lipkin model which contains an additional particle-scattering term. Three-body correlations in the ground state are necessary to preserve the hermiticity of the Hamiltonian matrix of ERPA. Two approximate forms of ERPA which neglect the three-body correlations are also applied to investigate the importance of three-body correlations. It is found that the ground-state energy is little affected by the inclusion of the three-body correlations. On the contrary, three-body correlations for the excited states can become quite important. (orig.)

Gravitational waves from periodic three-body systems.

Science.gov (United States)

Dmitrašinović, V; Suvakov, Milovan; Hudomal, Ana

2014-09-05

Three bodies moving in a periodic orbit under the influence of Newtonian gravity ought to emit gravitational waves. We have calculated the gravitational radiation quadrupolar waveforms and the corresponding luminosities for the 13+11 recently discovered three-body periodic orbits in Newtonian gravity. These waves clearly allow one to distinguish between their sources: all 13+11 orbits have different waveforms and their luminosities (evaluated at the same orbit energy and body mass) vary by up to 13 orders of magnitude in the mean, and up to 20 orders of magnitude for the peak values.

Collapse in a forced three-dimensional nonlinear Schrodinger equation

DEFF Research Database (Denmark)

Lushnikov, P.M.; Saffman, M.

2000-01-01

We derive sufficient conditions for the occurrence of collapse in a forced three-dimensional nonlinear Schrodinger equation without dissipation. Numerical studies continue the results to the case of finite dissipation.......We derive sufficient conditions for the occurrence of collapse in a forced three-dimensional nonlinear Schrodinger equation without dissipation. Numerical studies continue the results to the case of finite dissipation....

Relativistic two-body forces in many-body systems

International Nuclear Information System (INIS)

Namyslowski, J.M.

1979-01-01

For the fully off-shell extension in the relativistic dynamics, based on a covariant light-front field theory, we define the relative momenta and their proper angular variables such that -1 < cos theta/sub α/ < 1. In terms of these variables and the timelike total momenta we write explicitly the Weinberg interaction, corresponding to the exchange of a spinless particle of mass μ. The total momentum dependence and the cluster decomposition property of the Weinberg interaction are presented in detail, together with its energy dependence and other nonlocal features. In the nonrelativistic limit we recover the Yukawa interaction, while for the finite masses the Weinberg interaction is a product of the Yukawa interaction and a form factor. The Weinberg two-body force goes to zero at large energies and is truly nonlocal, in spite of the fact that the underlying field theory has a local Lagrangian

Diffusion Monte Carlo calculation of three-body systems

International Nuclear Information System (INIS)

Lu Mengjiao; Lin Qihu; Ren Zhongzhou

2012-01-01

The application of the diffusion Monte Carlo algorithm in three-body systems is studied. We develop a program and use it to calculate the property of various three-body systems. Regular Coulomb systems such as atoms, molecules, and ions are investigated. The calculation is then extended to exotic systems where electrons are replaced by muons. Some nuclei with neutron halos are also calculated as three-body systems consisting of a core and two external nucleons. Our results agree well with experiments and others' work. (authors)

Euler-Poincare Reduction of Externall Forced Rigid Body Motion

DEFF Research Database (Denmark)

Wisniewski, Rafal; Kulczycki, P.

2004-01-01

If a mechanical system experiences symmetry, the Lagrangian becomes invariant under a certain group action. This property leads to substantial simplification of the description of movement. The standpoint in this article is a mechanical system affected by an external force of a control action....... Assuming that the system possesses symmetry and the configuration manifold corresponds to a Lie group, the Euler-Poincaré reduction breaks up the motion into separate equations of dynamics and kinematics. This becomes of particular interest for modelling, estimation and control of mechanical systems......-known Euler-Poincaré reduction to a rigid body motion with forcing....

Three-body unitarity in the finite volume

Energy Technology Data Exchange (ETDEWEB)

Mai, M. [The George Washington University, Washington, DC (United States); Doering, M. [The George Washington University, Washington, DC (United States); Thomas Jefferson National Accelerator Facility, Newport News, VA (United States)

2017-12-15

The physical interpretation of lattice QCD simulations, performed in a small volume, requires an extrapolation to the infinite volume. A method is proposed to perform such an extrapolation for three interacting particles at energies above threshold. For this, a recently formulated relativistic 3 → 3 amplitude based on the isobar formulation is adapted to the finite volume. The guiding principle is two- and three-body unitarity that imposes the imaginary parts of the amplitude in the infinite volume. In turn, these imaginary parts dictate the leading power-law finite-volume effects. It is demonstrated that finite-volume poles arising from the singular interaction, from the external two-body sub-amplitudes, and from the disconnected topology cancel exactly leaving only the genuine three-body eigenvalues. The corresponding quantization condition is derived for the case of three identical scalar-isoscalar particles and its numerical implementation is demonstrated. (orig.)

iCub Whole-body Control through Force Regulation on Rigid Noncoplanar Contacts

Directory of Open Access Journals (Sweden)

Francesco eNori

2015-03-01

Full Text Available This paper details the implementation on the humanoid robot iCub of state-of-the-art algorithms for whole-body control. We regulate the forces between the robot and its surrounding environment to stabilize a desired robot posture. We assume that the forces and torques are exerted on rigid contacts. The validity of this assumption is guaranteed by constraining the contact forces and torques, e.g. the contact forces must belong to the associated friction cones. The implementation of this control strategy requires to estimate the external forces acting on the robot, and the internal joint torques. We then detail algorithms to obtain these estimations when using a robot with an iCub-like sensor set, i.e. distributed six-axis force-torque sensors and whole-body tactile sensors. A general theory for identifying the robot inertial parameters is also presented. From an actuation standpoint, we show how to implement a joint torque control in the case of DC brushless motors. In addition, the coupling mechanism of the iCub torso is investigated. The soundness of the entire control architecture is validated in a real scenario involving the robot iCub balancing and making contacts at both arms.

Strategic Rebalance of the Three Component Air Force

Science.gov (United States)

2013-03-01

Charles E. Stenner , Jr., “Three Component Air Force” terminology found in “State of the Air Force Reserve,” remarks at the Air Force Association’s...America Can Afford, (Washington, DC: 2013), 8, http://www.nationalguard.mil/features/ngps/2013_ngps.pdf (accessed February 10, 2013); Charles E. Stenner

Three-body molecular description of 9Be

International Nuclear Information System (INIS)

Revai, J.; Matveenko, A.V.

1979-01-01

The low lying spectrum of the 9 Be nucleus is calculated in the α+α+n three-body model. The molecular approach to this three-body problem based on the exact evalution of the two-center wave functions for separable n-α potentials is considered in detail. The numerical results are obtained in the generalized Born-Oppenheimer approximation which preserves total angular momentum and parity

Development and initial validation of the Gay Men's Physical Attractiveness Scale

OpenAIRE

Elmer, Eddy Michael

2012-01-01

Young and older gay men from 40 countries rated the importance of 258 body features in judging the physical attractiveness of other men (N = 3,600). Exploratory factor analyses using two separate, independent samples suggested four factors underlying male same-sex physical attractiveness: Facial Attractiveness; Muscularity/Body Shape; Body Fat/Overall Appearance; and Intimate Regions. Twenty items representing the four dimensions were selected. Confirmatory factor analytic models using two ot...

Shell structure of the A = 6 ground states from three-body dynamics

International Nuclear Information System (INIS)

Lehman, D.R.; Parke, W.C.

1983-01-01

Three-body (αNN) models of the 6 He and 6 Li ground states are used to investigate their shell structure. Three models for each nucleus are considered: simple, full (nn), and full (np) for 6 He, and simple, full (0%), and full (4%) for 6 Li. The full models in both cases are obtained by including the S/sub 1/2/, P/sub 1/2/, and P/sub 3/2/ partial waves of the αN interaction, whereas the simple model truncates to only the strongly resonant P/sub 3/2/ wave. The 6 He full models distinguish between use of the nn or np parameters for the 1 S 0 NN interaction, while the 6 Li full models have either a pure 3 S 1 NN interaction (0%) or a 3 S 1 - 3 D 1 interaction that leads to a 4% d-wave component in the deuteron (4%). These models are used to calculate the probabilities of the orbital components of the wave functions, the configuration-space single-particle orbital densities, and the configuration-space two-particle wave function amplitudes in j-j coupling with the nucleon coordinates referred to the alpha particle as the ''core'' or ''center of force.'' The results are then compared with those from phenomenological and realistic-interaction shell models. Major findings of the comparison are the following: None of the shell models considered have a distribution of orbital probabilities across shells like that predicted by three-body models; the orbital rms radii from three-body models indicate an ordering of the orbits within shells, i.e., p/sub 1/2/ outside p/sub 3/2/, unlike oscillator shell models with a single oscillator parameter where the p-shell orbitals have the same shape; and, as expected, three-body orbital densities decay at large radial distances as exponentials rather than the too compact Gaussian falling off of oscillator shell models

Male and Female Perception of Physical Attractiveness

Directory of Open Access Journals (Sweden)

Ray Garza

2016-02-01

Full Text Available Waist-to-hip ratio (WHR and breast size are morphological traits that are associated with female attractiveness. Previous studies using line drawings of women have shown that men across cultures rate low WHRs (0.6 and 0.7 as most attractive. In this study, we used additional viewing measurements (i.e., first fixation duration and visual regressions to measure visual attention and record how long participants first focused on the female body and whether they regressed back to an area of interest. Additionally, we manipulated skin tone to determine whether they preferred light- or dark-skinned women. In two eye tracking experiments, participants rated the attractiveness of female nude images varying in WHR (0.5–0.9, breast size, and skin tone. We measured first fixation duration, gaze duration, and total time. The overall results of both studies revealed that visual attention fell mostly on the face, the breasts, and the midriff of the female body, supporting the evolutionary view that reproductively relevant regions of the female body are important to female attractiveness. Because the stimuli varied in skin tone and the participants were mainly Hispanic of Mexican American descent, the findings from these studies also support a preference for low WHRs and reproductively relevant regions of the female body.

The three-body problem from Pythagoras to Hawking

CERN Document Server

Valtonen, Mauri; Kholshevnikov, Konstantin; Mylläri, Aleksandr; Orlov, Victor; Tanikawa, Kiyotaka

2016-01-01

This book, written for a general readership, reviews and explains the three-body problem in historical context reaching to latest developments in computational physics and gravitation theory. The three-body problem is one of the oldest problems in science and it is most relevant even in today’s physics and astronomy. The long history of the problem from Pythagoras to Hawking parallels the evolution of ideas about our physical universe, with a particular emphasis on understanding gravity and how it operates between astronomical bodies. The oldest astronomical three-body problem is the question how and when the moon and the sun line up with the earth to produce eclipses. Once the universal gravitation was discovered by Newton, it became immediately a problem to understand why these three-bodies form a stable system, in spite of the pull exerted from one to the other. In fact, it was a big question whether this system is stable at all in the long run. Leading mathematicians attacked this problem over more than...

Three-Body Potentials in α-Particle Model of Light Nuclei

International Nuclear Information System (INIS)

Ishikawa, Souichi

2017-01-01

In three-body model calculations of atomic nuclei, e.g., the "1"2C nucleus as α-α-α system and the "9Be nucleus as α-α-n system, the Hamiltonians of the systems consisting of two- and three-body potentials are important inputs. However, our knowledge of three-body potentials is quite restricted. In this paper, I will examine a relation between α-α-α and α-α-n three-body potentials that is obtained in a simple cluster model picture, which gives a phenomenological constraint condition on the three-body potential models to be used. (author)

Atomic Color Superfluid via Three-Body Loss

International Nuclear Information System (INIS)

Kantian, A.; Diehl, S.; Zoller, P.; Daley, A. J.; Dalmonte, M.; Hofstetter, W.

2009-01-01

Large three-body loss rates in a three-component Fermi gas confined in an optical lattice can dynamically prevent atoms from tunneling so as to occupy a lattice site with three atoms. This effective constraint not only suppresses the occurrence of actual loss events, but stabilizes BCS-pairing phases by suppressing the formation of trions. We study the effect of the constraint on the many-body physics using bosonization and density matrix renormalization group techniques, and also investigate the full dissipative dynamics including loss for the example of 6 Li.

Lavine method applied to three body problems

International Nuclear Information System (INIS)

Mourre, Eric.

1975-09-01

The methods presently proposed for the three body problem in quantum mechanics, using the Faddeev approach for proving the asymptotic completeness, come up against the presence of new singularities when the potentials considered v(α)(x(α)) for two-particle interactions decay less rapidly than /x(α)/ -2 ; and also when trials are made for solving the problem with a representation space whose dimension for a particle is lower than three. A method is given that allows the mathematical approach to be extended to three body problem, in spite of singularities. Applications are given [fr

Three-dimensional analyses of human bite-force magnitude and moment.

Science.gov (United States)

van Eijden, T M

1991-01-01

The effect of the three-dimensional orientation of occlusal force on maximal bite-force magnitude was examined in seven human subjects at three different unilateral anteroposterior bite positions (canine, second premolar and second molar). At each position, bite-force magnitude was registered in 17 precisely defined directions using a three-component force transducer and a feedback method. In addition, to assess the efficiency of transfer of muscle to bite force, for bites produced in the sagittal plane, moment-arm length was determined and the produced bite-force moment calculated. The results showed that the largest possible bite force was not always produced in a direction perpendicular to the occlusal plane. Generally, maximal bite force in medial and posterior directions was larger than that in, respectively, corresponding lateral and anterior directions. In each direction the produced force was larger at the posterior bite point than at the anterior bite point. The combined moment produced by the jaw muscles was largest for vertical bites, smallest for posteriorly directed bites and intermediate for anteriorly directed bites. In the case of vertically and anteriorly directed bites the produced moment did not vary significantly with the bite position. Hence, for these bite positions the jaw closing moment of the muscles must have kept constant. In the case of posteriorly directed bites the produced moment decreased when bite position changed from the anterior to the posterior side of the dentition. This indicated that jaw muscle activity had declined.

Three-dimensional Force and Kinematic Interactions in V1 Skating at High Speeds.

Science.gov (United States)

Stöggl, Thomas; Holmberg, Hans-Christer

2015-06-01

To describe the detailed kinetics and kinematics associated with use of the V1 skating technique at high skiing speeds and to identify factors that predict performance. Fifteen elite male cross-country skiers performed an incremental roller-skiing speed test (Vpeak) on a treadmill using the V1 skating technique. Pole and plantar forces and whole-body kinematics were monitored at four submaximal speeds. The propulsive force of the "strong side" pole was greater than that of the "weak side" (P skating at high speeds. The faster skiers exhibit more symmetric leg motion on the "strong" and "weak" sides, as well as more synchronized poling. With respect to methods, the pressure insoles and three-dimensional kinematics in combination with the leg push-off model described here can easily be applied to all skating techniques, aiding in the evaluation of skiing techniques and comparison of effectiveness.

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

Science.gov (United States)

Lee, Dominic J O'

2015-04-15

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.

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

International Nuclear Information System (INIS)

Lee, Dominic J

2015-01-01

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)

Development of a Force Measurement Device for Lower-Body Muscular Strength Measuring of Skaters

Science.gov (United States)

Kim, Dong Ki; Lee, Jeong Tae

This paper presents a force measurement system that can measure a lower-body muscular strength of skaters. The precise measurement and analysis of the left and right lower-body strength of skaters is necessary, because a left/right lower-body strength balance is helpful to improve the athletes' performance and to protect them from injury. The system is constructed with a skate sliding board, a couple of sensor-units with load cell, indicator and control box, guard, force pad, and support bracket. The developed force measurement system is calibrated by the calibration setup, and the uncertainty of the force sensing unit on the left is within 0.087% and the uncertainty of the force sensing unit on the right is within 0.109%. In order to check the feasibility of the developed measurement device, a kinematic analysis is conducted with skater. As a result, the subject shows the deviation of left and right of 12.1 N with respect to average strength and 39.1 N with respect to the maximum strength. This evaluation results are reliable enough to make it possible to measure a lower-body muscular strength of skaters. The use of this measurement system will be expected to correct the posture of skaters and record the sports dynamics data for each athlete. It is believed that through the development of this equipment, skaters in elementary, middle, high schools, colleges, and the professional level have the systematic training to compete with world-class skaters.

Chiral symmetry and many-body forces in nuclei

International Nuclear Information System (INIS)

Nyman, E.M.; Rho, M.

1976-01-01

It is demonstrated that when quantum corrections are added, chiral Lagrangians need not generate strong many-body forces as they do in tree approximation. It is suggested that a physically reasonable procedure is to adjust the sigma-model parameters so as not to conflict with the current status of nuclear theory. As a consequence, the equilibrium density of abnormal states could be pushed up further, and the binding energy be considerably reduced. (Auth.)

Covariant equations for the three-body bound state

International Nuclear Information System (INIS)

Stadler, A.; Gross, F.; Frank, M.

1997-01-01

The covariant spectator (or Gross) equations for the bound state of three identical spin 1/2 particles, in which two of the three interacting particles are always on shell, are developed and reduced to a form suitable for numerical solution. The equations are first written in operator form and compared to the Bethe-Salpeter equation, then expanded into plane wave momentum states, and finally expanded into partial waves using the three-body helicity formalism first introduced by Wick. In order to solve the equations, the two-body scattering amplitudes must be boosted from the overall three-body rest frame to their individual two-body rest frames, and all effects which arise from these boosts, including Wigner rotations and p-spin decomposition of the shell-particle, are treated exactly. In their final form, the equations reduce to a coupled set of Faddeev-like double integral equations with additional channels arising from the negative p-spin states of the off-shell particle

The Ay puzzle and the nuclear force

International Nuclear Information System (INIS)

Hueber, D.; Friar, J.L.

1998-01-01

The nucleon-deuteron analyzing power A y in elastic nucleon-deuteron scattering poses a longstanding puzzle. At energies E lab below approximately 30 MeV A y cannot be described by any realistic nucleon-nucleon (NN) force. The inclusion of existing three-nucleon forces does not improve the situation. Because of recent questions about the 3 P J NN phases, we examine whether reasonable changes in the NN force can resolve the puzzle. In order to do this we investigate the effect on the 3 P J waves produced by changes in different parts of the potential (viz., the central force, tensor force, etc.), as well as on the two-body observables and on A y . We find that it is not possible with reasonable changes in the NN potential to increase the three-body A y and at the same time to keep the two-body observables unchanged. We therefore conclude that the A y puzzle is likely to be solved by new three-nucleon forces, such as those of the spin-orbit type, which have not yet been taken into account. copyright 1998 The American Physical Society

An Eye Tracking Examination of Men’s Attractiveness by Conceptive Risk Women

Directory of Open Access Journals (Sweden)

Ray Garza

2017-01-01

Full Text Available Previous research has indicated that women prefer men who exhibit an android physical appearance where fat distribution is deposited on the upper body (i.e., shoulders and arms and abdomen. This ideal physical shape has been associated with perceived dominance, health, and immunocompetence. Although research has investigated attractability of men with these ideal characteristics, research on how women visually perceive these characteristics is limited. The current study investigated visual perception and attraction toward men in Hispanic women of Mexican American descent. Women exposed to a front-posed image, where the waist-to-chest ratio (WCR and hair distribution were manipulated, rated men’s body image associated with upper body strength (low WCR 0.7 as more attractive. Additionally, conceptive risk did not play a strong role in attractiveness and visual attention. Hair distribution did not contribute to increased ratings of attraction but did contribute to visual attraction when measuring total time where men with both facial and body hair were viewed longer. These findings suggest that physical characteristics in men exhibiting upper body strength and dominance are strong predictors of visual attraction.

Unconscious processing of facial attractiveness: invisible attractive faces orient visual attention.

Science.gov (United States)

Hung, Shao-Min; Nieh, Chih-Hsuan; Hsieh, Po-Jang

2016-11-16

Past research has proven human's extraordinary ability to extract information from a face in the blink of an eye, including its emotion, gaze direction, and attractiveness. However, it remains elusive whether facial attractiveness can be processed and influences our behaviors in the complete absence of conscious awareness. Here we demonstrate unconscious processing of facial attractiveness with three distinct approaches. In Experiment 1, the time taken for faces to break interocular suppression was measured. The results showed that attractive faces enjoyed the privilege of breaking suppression and reaching consciousness earlier. In Experiment 2, we further showed that attractive faces had lower visibility thresholds, again suggesting that facial attractiveness could be processed more easily to reach consciousness. Crucially, in Experiment 3, a significant decrease of accuracy on an orientation discrimination task subsequent to an invisible attractive face showed that attractive faces, albeit suppressed and invisible, still exerted an effect by orienting attention. Taken together, for the first time, we show that facial attractiveness can be processed in the complete absence of consciousness, and an unconscious attractive face is still capable of directing our attention.

Attracting electromagnet for control rod

International Nuclear Information System (INIS)

Kato, Kazuo; Sasaki, Kotaro.

1989-01-01

Non-magnetic material plates with inherent resistivity of greater than 20 μΩ-cm and thickness of less than 3 mm are used for the end plates of attracting electromagnets for closed type control rods. By using such control rod attracting electromagnets, the scram releasing time can be shortened than usual. Since the armature attracting side of the electromagnet has to be sealed by a non-magnetic plate, a bronze plate of about 5 mm thickness has been used so far. Accordingly, non-magnetic plate is inserted to the electromagnet attracting face to increase air source length for improving to shorten the scram releasing time. This method, however, worsens the attracting property on one hand to require a great magnetomotive force. For overcoming these drawbacks, in the present invention, the material for tightly closing end plates in an electromagnet is changed from bronze plate to non-magnetic stainless steel SUS 303 or non-magnetic Monel metal and, in addition, the plate thickness is reduced to less than 5 mm thereby maintaining the attracting property and shortening the scram releasing time. (K.M.)

Theoretical modeling of the effect of Casimir attraction on the electrostatic instability of nanowire-fabricated actuators

Science.gov (United States)

Mokhtari, J.; Farrokhabadi, A.; Rach, R.; Abadyan, M.

2015-04-01

The presence of the quantum vacuum fluctuations, i.e. the Casimir attraction, can strongly affect the performance of ultra-small actuators. The strength of the Casimir force is significantly influenced by the geometries of interacting bodies. Previous research has exclusively studied the impact of the vacuum fluctuations on the instability of nanoactuators with planar geometries. However, no work has yet considered this phenomenon in actuators fabricated from nanowires/nanotubes with cylindrical geometries. In our present work, the influence of the Casimir attraction on the electrostatic stability of nanoactuators fabricated from cylindrical conductive nanowire/nanotube is investigated. The Dirichlet mode is considered and an asymptotic solution, based on scattering theory, is applied to consider the effect of vacuum fluctuations in the theoretical model. The size-dependent modified couple stress theory is employed to derive the constitutive equation of the actuator. The governing nonlinear equations are solved by two different approaches, i.e. the finite difference method and modified Adomian-Padé method. Various aspects of the problem, i.e. comparison with the van der Waals force regime, the variation of instability parameters, effect of geometry and coupling between the Casimir force and size dependency are discussed. This work is beneficial to determine the impact of Casimir force on nanowire/nanotube-fabricated actuators.

Observation of the Borromean Three-Body Förster Resonances for Three Interacting Rb Rydberg Atoms.

Science.gov (United States)

Tretyakov, D B; Beterov, I I; Yakshina, E A; Entin, V M; Ryabtsev, I I; Cheinet, P; Pillet, P

2017-10-27

Three-body Förster resonances at long-range interactions of Rydberg atoms were first predicted and observed in Cs Rydberg atoms by Faoro et al. [Nat. Commun. 6, 8173 (2015)NCAOBW2041-172310.1038/ncomms9173]. In these resonances, one of the atoms carries away an energy excess preventing the two-body resonance, leading thus to a Borromean type of Förster energy transfer. But they were in fact observed as the average signal for the large number of atoms N≫1. In this Letter, we report on the first experimental observation of the three-body Förster resonances 3×nP_{3/2}(|M|)→nS_{1/2}+(n+1)S_{1/2}+nP_{3/2}(|M^{*}|) in a few Rb Rydberg atoms with n=36, 37. We have found here clear evidence that there is no signature of the three-body Förster resonance for exactly two interacting Rydberg atoms, while it is present for N=3-5 atoms. This demonstrates the assumption that three-body resonances can generalize to any Rydberg atom. As such resonance represents an effective three-body operator, it can be used to directly control the three-body interactions in quantum simulations and quantum information processing with Rydberg atoms.

The force law for the dynamic two-body problem in the second post-Newtonian approximation of general relativity

International Nuclear Information System (INIS)

Breuer, R.A.; Rudolph, E.

1982-01-01

The force between two well-separated bodies is calculated in a fully dynamic system of two extended bodies up to and including the second post-Newtonian approximation (PNA). The iteration procedure as formulated by Anderson and Decanio is used in a version whose divergences have been pushed to the third PNA. The following are shown: (i) The force law assumes the ''Newtonian form'' if a second approximation in 1/(separation of the bodies) is made; (ii) the mass terms appearing in the force law are the (Tolman) masses of the individual bodies expanded up the second PNA; the internal masses equal the (passive and active) gravitational masses of the bodies in order considered; they are all constants of the motion; (iii) the self-fields of the bodies vanish in the second PNA; hence there is no Nordvedt effect in the second PNA; (iv) the compactness of the bodies, i.e., (gravitational radius)/(body size), does not appear in the force law; only the relation between mass and the matter variables is changed in the PNA as compared with the corresponding Newtonian result. (author)

Spectral sum rules for the three-body problem

International Nuclear Information System (INIS)

Bolle, D.; Osborn, T.A.

1982-01-01

This paper derives a number of sum rules for nonrelativistic three-body scattering. These rules are valid for any finite region μ in the six-dimensional coordinate space. They relate energy moments of the trace of the onshell time-delay operator to the energy-weighted probability for finding the three-body bound-state wave functions in the region μ. If μ is all of the six-dimensional space, the global form of the sum rules is obtained. In this form the rules constitute higher-order Levinson's theorems for the three-body problem. Finally, the sum rules are extended to allow the energy momtns have complex powers

Analysis of Three-Nucleon Forces Effects in the A = 3 System

International Nuclear Information System (INIS)

Kievsky, A.

2011-01-01

study directed to determine the parametrizations of the profile functions inside the three-body force from the experimental data. Investigations in this direction are underway. (author)

Cognitive Processing about Classroom-Relevant Contexts: Teachers' Attention to and Utilization of Girls' Body Size, Ethnicity, Attractiveness, and Facial Affect

Science.gov (United States)

Wang, Shirley S.; Treat, Teresa A.; Brownell, Kelly D.

2008-01-01

This study examines 2 aspects of cognitive processing in person perception--attention and decision making--in classroom-relevant contexts. Teachers completed 2 implicit, performance-based tasks that characterized attention to and utilization of 4 student characteristics of interest: ethnicity, facial affect, body size, and attractiveness. Stimuli…

Scaling of lifting forces in relation to object size in whole body lifting

NARCIS (Netherlands)

Kingma, I.; van Dieen, J.H.; Toussaint, H.M.

2005-01-01

Subjects prepare for a whole body lifting movement by adjusting their posture and scaling their lifting forces to the expected object weight. The expectancy is based on visual and haptic size cues. This study aimed to find out whether lifting force overshoots related to object size cues disappear or

Raman non-coincidence effect of boroxol ring: The interplay between repulsion and attraction forces in the glassy, supercooled and liquid state

Science.gov (United States)

Kalampounias, Angelos G.; Papatheodorou, George N.

2018-06-01

Temperature dependent Raman spectra of boric oxide have been measured in a temperature range covering the glassy, supercooled and liquid state. The shift of the isotropic band assigned to boroxol rings relative to the anisotropic component upon heating the glass is measured and attributed to the Raman non-coincidence effect. The measured shift is associated with the competition between attraction and repulsion forces with increasing temperature. The relation of dephasing and orientational relaxation times to the non-coincidence effect of the condensed phases has been examined. We discuss our results in the framework of the current phenomenological status of the field in an attempt to separate the attraction and repulsion contributions corresponding to the observed non-coincidence effect.

A simple coordinate space approach to three-body problems ...

Indian Academy of Sciences (India)

We show how to treat the dynamics of an asymmetric three-body system consisting of one heavy and two identical light particles in a simple coordinate space variational approach. The method is constructive and gives an efficient way of resolving a three-body system to an effective two-body system. It is illustrated by ...

Quantum anticentrifugal force

International Nuclear Information System (INIS)

Cirone, M.A.; Schleich, W.P.; Straub, F.; Rzazewski, K.; Wheeler, J.A.

2002-01-01

In a two-dimensional world, a free quantum particle of vanishing angular momentum experiences an attractive force. This force originates from a modification of the classical centrifugal force due to the wave nature of the particle. For positive energies the quantum anticentrifugal force manifests itself in a bunching of the nodes of the energy wave functions towards the origin. For negative energies this force is sufficient to create a bound state in a two-dimensional δ-function potential. In a counterintuitive way, the attractive force pushes the particle away from the location of the δ-function potential. As a consequence, the particle is localized in a band-shaped domain around the origin

Local Momenta and a Three-Body Gauge

Science.gov (United States)

Schillaci, Michael Jay

2000-06-01

Here I discuss position-dependent, phlocal momentum which depend upon the logarithmic gradient of a continuum Coulomb pair. These momenta have become increasingly important in the modeling of three-body scattering phenomena, while their precise mathematical and physical nature has remained unexplored. These momenta are analytic at all values of the radial separation, except possibly at zero, and can be used to illustrate why the reigning 3C wavefunction works so well in describing many phlight-atom ion processes. I calculate the contributions for several subsystems, and explain the schillaci/threebody/ momentum.html>asymmetric results achieved by Wiese(L.M. Wiese phet al.), PRL 25, 4982 (1997)., on the breakup of the (H_3^+) ion - a massive three-body system. I propose that the local momentum herein formulated become part of a three-body gauge constraint. When applied, a non-vanishing, position-dependent phase will modulate the resulting transition amplitude. The size of this modulation depends critically upon the system.

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

DEFF Research Database (Denmark)

Jørgensen, Nils Byg

2016-01-01

(BEC) has not yet been realized. Here, we use radio frequency spectroscopy of ultracold bosonic 39K atoms to experimentally demonstrate the existence of a well-defined quasiparticle state of an impurity interacting with a BEC. We measure the energy of the impurity both for attractive and repulsive...... interactions, and find excellent agreement with theories that incorporate three-body correlations. The spectral response consists of a well-defined quasiparticle peak at weak coupling, while for increasing interaction strength, the spectrum is strongly broadened and becomes dominated by the many-body continuum...

Height and Body Composition Determine Arm Propulsive Force in Youth Swimmers Independent of a Maturation Stage

OpenAIRE

Moura, Tatiane; Costa, Manoel; Oliveira, Saulo; Júnior, Marcos Barbosa; Ritti-Dias, Raphael; Santos, Marcos

2014-01-01

The aim of this study was to examine the relationship between anthropometric variables, body composition and propulsive force in swimmers aged 9–17 years. Anthropometric characteristics (body height and mass, sitting height, arm span, arm muscle area and body composition) and the propulsive force of the arm (tethered swimming test) were evaluated in 56 competitive male swimmers. Tanner’s stages of genital maturation (P1–5) were used. The data analysis included correlations and multiple linear...

QED effects in high-Z atoms; three-body potentials

International Nuclear Information System (INIS)

Zygelman, B.

1983-01-01

Electromagnetic three-body potentials were first studied by Primakoff and Holstein. Later, Chamugan and Schweber rederived these potentials and pointed out that they might be important in highly relativistic systems, however, their formulation was basically nonrelativistic. Mittleman, in a series of papers, constructed configuration space equations that included three-body potentials. His derivation started from first principles i.e. QED, and the resulting three-body potentials are more general than the Primakoff-Holstein potentials. In this thesis the contribution to the binding energy of a simple high-Z ion from the three-body potentials is calculated. In addition, the nature and structure of these potentials in greater detail are studied. Some ambiguities that arise when the transition from Fock to configuration space is made are studied in detail

What is an attractive body? Using an interactive 3D program to create the ideal body for you and your partner.

Directory of Open Access Journals (Sweden)

Kara L Crossley

Full Text Available What is the ideal body size and shape that we want for ourselves and our partners? What are the important physical features in this ideal? And do both genders agree on what is an attractive body? To answer these questions we used a 3D interactive software system which allows our participants to produce a photorealistic, virtual male or female body. Forty female and forty male heterosexual Caucasian observers (females mean age 19.10 years, s.d. 1.01; 40 males mean age 19.84, s.d. 1.66 set their own ideal size and shape, and the size and shape of their ideal partner using the DAZ studio image manipulation programme. In this programme the shape and size of a 3D body can be altered along 94 independent dimensions, allowing each participant to create the exact size and shape of the body they want. The volume (and thus the weight assuming a standard density and the circumference of the bust, waist and hips of these 3D models can then be measured. The ideal female body set by women (BMI = 18.9, WHR = 0.70, WCR = 0.67 was very similar to the ideal partner set by men, particularly in their BMI (BMI = 18.8, WHR = 0.73, WCR = 0.69. This was a lower BMI than the actual BMI of 39 of the 40 women. The ideal male body set by the men (BMI = 25.9, WHR = 0.87, WCR = 0.74 was very similar to the ideal partner set by the women (BMI = 24.5, WHR = 0.86, WCR = 0.77. This was a lower BMI than the actual BMI of roughly half of the men and a higher BMI than the other half. The results suggest a consistent preference for an ideal male and female body size and shape across both genders. The results also suggest that both BMI and torso shape are important components for the creation of the ideal body.

Euler-Poincaré Reduction of Externally Forced Rigid Body Motion

DEFF Research Database (Denmark)

Wisniewski, Rafal; Kulczycki, P.

2004-01-01

If a mechanical system experiences symmetry, the Lagrangian becomes invariant under a certain group action. This property leads to substantial simplification of the description of movement. The standpoint in this article is a mechanical system affected by an external force of a control action....... Assuming that the system possesses symmetry and the configuration manifold corresponds to a Lie group, the Euler-Poincaré reduction breaks up the motion into separate equations of dynamics and kinematics. This becomes of particular interest for modelling, estimation and control of mechanical systems......-known Euler-Poincaré reduction to a rigid body motion with forcing....

NUMERICAL ESTIMATES OF ELECTRODYNAMICS PROCESSES IN THE INDUCTOR SYSTEM WITH AN ATTRACTIVE SCREEN AND A FLAT RECTANGULAR SOLENOID

Directory of Open Access Journals (Sweden)

E. A. Chaplygin

2018-04-01

Full Text Available Purpose. To carry out numerical estimates of currents and forces in the investigated inductor system with an attractive screen (ISAS and determine the effectiveness of the force attraction. Methodology. The calculated relationships and graphical constructions were obtained using the initial data of the system: induced current in the screen and sheet metal; the distributed force of attraction (Ampère force; the repulsive force acting on the sheet metal (Lorentz force; amplitude values of the force of attraction and repulsion; phase dependence of the force of attraction, the repulsive force and the total resulting force. Results. The results of calculations in the form of graphical dependencies of electrodynamic processes in the region under the conductors of a rectangular solenoid of inductor system with an attracting screen are presented. The graphs of forces and currents in region of dent are obtained. In the paper the analysis of electrodynamics processes for whole area under the winding of inductor system with an attractive screen is shown. The flowing this processes in the region of dent a given geometry is presented. Originality. The considered inductor system with an attractive screen and a rectangular solenoid is improved, in comparison with the previous developed ISAS. It has a working area under the lines of parallel conductors in the cross section of a rectangular solenoid, and this allows to place a predetermined portion of the sheet metal anywhere within the working region. Comparison of the indicators of electrodynamics processes in the considered variants of calculation shows an approximate growth of almost 1.5 times the power indicators in the area of the accepted dent in comparison with similar values for the entire area under the winding of the ISAS. Practical value. The results obtained are important for the practice of real estimates of the excited forces of attraction. With a decrease in the dent, the amplitude of the

AN ACCURATE ORBITAL INTEGRATOR FOR THE RESTRICTED THREE-BODY PROBLEM AS A SPECIAL CASE OF THE DISCRETE-TIME GENERAL THREE-BODY PROBLEM

International Nuclear Information System (INIS)

Minesaki, Yukitaka

2013-01-01

For the restricted three-body problem, we propose an accurate orbital integration scheme that retains all conserved quantities of the two-body problem with two primaries and approximately preserves the Jacobi integral. The scheme is obtained by taking the limit as mass approaches zero in the discrete-time general three-body problem. For a long time interval, the proposed scheme precisely reproduces various periodic orbits that cannot be accurately computed by other generic integrators

Three-particle forces and nuclear models

International Nuclear Information System (INIS)

Krutov, V.A.

1980-01-01

Different nuclear models accounting and unaccounting for three-particle internucleon forces (TIF) are reviewed. At present only two nuclear models use manifestly TIP: the Vautherin-Brink-Skyrme (VBS) model and the model proposed by the author of the review and called the semiphenomenological (SP) nuclear model. There is a short discussion of major drawbacks of models unaccounting for TIF: multiparticle shell model, ''superfluid model'', Harty-Fock calculations with two-particle forces, Bruckner-Hartry-Fock calculations, the relativistic self-consistent nuclear model. The VBS and SP models are discussed in detail. It is concluded, that the employment of TIF even in a very simplified form (extremely short-range) puts away a lot of problems characteristic to models limited by two-particle forces (collapse at iteratious in Hartry-Fock, simultaneous fitting of the binding energy of a nucleus and the binding energy of a nucleon, etc.) and makes it possible to obtain in a rather simple way such nuclear characteristics as nuclear binding energy, nuclear mean square root radii, nucleon density of a nucleus

Women's meta-perceptions of attractiveness and their relations to body image

NARCIS (Netherlands)

Dijkstra, Pieternel; Barelds, Dick P. H.

The present study examined meta-perceptions of attractiveness among women. More specifically, ratings were collected about how women thought their partner, family and friends, and strangers would view their physical attractiveness. In an online survey, 1287 Dutch women (aged 19-80 years) answered

Few-body strange systems

International Nuclear Information System (INIS)

Gibson, B.F.

1985-01-01

Three fascinating aspects of few-body Λ-hypernuclei are discussed: 3-body forces, charge symmetry breaking, and ΛN-ΣN coupling. The need for improved data on hyperon-nucleon scattering is emphasized. 29 refs., 3 tabs

Force generation due to three-dimensional plasma discharge on a conical forebody using pulsed direct current actuators

International Nuclear Information System (INIS)

Singh, Kunwar Pal; Roy, Subrata

2008-01-01

Understanding the behavior of three-dimensional plasmas around a pulsed dc actuator can be useful for its efficient operation in many applications. The effect of such actuators is studied using a self-consistent multibody system of neutral oxygen species and its plasma. The equations governing the motion of charged species are solved with the drift diffusion approximation. The electrostatic potential is computed from Poisson's equation. The electric field and ionization level are the highest close to the junction of electrodes and dielectric. The plasma body force thus generated also follows a similar characteristic. Results also show some dc corona instabilities. The temporal average of such force shows mostly acceleration from anode to cathode above the actuator

Design and performance of a high-resolution frictional force microscope with quantitative three-dimensional force sensitivity

International Nuclear Information System (INIS)

Dienwiebel, M.; Kuyper, E. de; Crama, L.; Frenken, J.W.M.; Heimberg, J.A.; Spaanderman, D.-J.; Glatra van Loon, D.; Zijlstra, T.; Drift, E. van der

2005-01-01

In this article, the construction and initial tests of a frictional force microscope are described. The instrument makes use of a microfabricated cantilever that allows one to independently measure the lateral forces in X and Y directions as well as the normal force. We use four fiber-optic interferometers to detect the motion of the sensor in three dimensions. The properties of our cantilevers allow easy and accurate normal and lateral force calibration, making it possible to measure the lateral force on a fully quantitative basis. First experiments on highly oriented pyrolytic graphite demonstrate that the microscope is capable of measuring lateral forces with a resolution down to 15 pN

A three-axis force sensor for dual finger haptic interfaces.

Science.gov (United States)

Fontana, Marco; Marcheschi, Simone; Salsedo, Fabio; Bergamasco, Massimo

2012-10-10

In this work we present the design process, the characterization and testing of a novel three-axis mechanical force sensor. This sensor is optimized for use in closed-loop force control of haptic devices with three degrees of freedom. In particular the sensor has been conceived for integration with a dual finger haptic interface that aims at simulating forces that occur during grasping and surface exploration. The sensing spring structure has been purposely designed in order to match force and layout specifications for the application. In this paper the design of the sensor is presented, starting from an analytic model that describes the characteristic matrix of the sensor. A procedure for designing an optimal overload protection mechanism is proposed. In the last part of the paper the authors describe the experimental characterization and the integrated test on a haptic hand exoskeleton showing the improvements in the controller performances provided by the inclusion of the force sensor.

A Three-Axis Force Sensor for Dual Finger Haptic Interfaces

Directory of Open Access Journals (Sweden)

Fabio Salsedo

2012-10-01

Full Text Available In this work we present the design process, the characterization and testing of a novel three-axis mechanical force sensor. This sensor is optimized for use in closed-loop force control of haptic devices with three degrees of freedom. In particular the sensor has been conceived for integration with a dual finger haptic interface that aims at simulating forces that occur during grasping and surface exploration. The sensing spring structure has been purposely designed in order to match force and layout specifications for the application. In this paper the design of the sensor is presented, starting from an analytic model that describes the characteristic matrix of the sensor. A procedure for designing an optimal overload protection mechanism is proposed. In the last part of the paper the authors describe the experimental characterization and the integrated test on a haptic hand exoskeleton showing the improvements in the controller performances provided by the inclusion of the force sensor.

Attractive forces in microporous carbon electrodes for capacitive deionization

NARCIS (Netherlands)

Biesheuvel, P.M.; Porada, S.; Levi, M.; Bazant, M.Z.

2014-01-01

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

Effects of physical attractiveness on political beliefs.

Science.gov (United States)

Peterson, Rolfe Daus; Palmer, Carl L

2017-01-01

Physical attractiveness is an important social factor in our daily interactions. Scholars in social psychology provide evidence that attractiveness stereotypes and the "halo effect" are prominent in affecting the traits we attribute to others. However, the interest in attractiveness has not directly filtered down to questions of political behavior beyond candidates and elites. Utilizing measures of attractiveness across multiple surveys, we examine the relationship between attractiveness and political beliefs. Controlling for socioeconomic status, we find that more attractive individuals are more likely to report higher levels of political efficacy, identify as conservative, and identify as Republican. These findings suggest an additional mechanism for political socialization that has further implications for understanding how the body intertwines with the social nature of politics.

Are Brazil nuts attractive?

Science.gov (United States)

Sanders, Duncan A; Swift, Michael R; Bowley, R M; King, P J

2004-11-12

We present event-driven simulation results for single and multiple intruders in a vertically vibrated granular bed. Under our vibratory conditions, the mean vertical position of a single intruder is governed primarily by a buoyancylike effect. Multiple intruders also exhibit buoyancy governed behavior; however, multiple neutrally buoyant intruders cluster spontaneously and undergo horizontal segregation. These effects can be understood by considering the dynamics of two neutrally buoyant intruders. We have measured an attractive force between such intruders which has a range of five intruder diameters, and we provide a mechanistic explanation for the origins of this force.

Quasi-Three Body Systems: Properties and Scattering

International Nuclear Information System (INIS)

Amusia, M. Ya.

2017-01-01

We investigate systems of three mutually interacting particles with masses m e , m μ , M that obey the following inequality m e ≪ m μ ≪ M. Then the three-body problem reduces to the two-body scattering or structure of m e in the field of the pseudo-nucleus m μ M. We calculate analytically the properties of considered systems, such as the scattering cross-sections, hyperfine splitting, Auger decay of exited states and Lamb shifts, presenting them as expansions in powers of the parameter β=m e /m μ ≪1. (author)

Effects of experimental muscle pain on force variability during task-related and three directional isometric force task

DEFF Research Database (Denmark)

Mista, Christian Ariel; Graven-Nielsen, Thomas

2013-01-01

was measured using sample entropy (SEn). Three-way repeated measures ANOVA with factors level of contraction, pain/control, and time were performed for the CV, the CoP, and the SEn of each component of the force. In the tangential forces, no significant effects were found for the 3D matching tasks. The ANOVA.......05). In the task-related force, no significant effects were found for the CV during the three-dimensional task or for the task-related task. Finally, the ANOVA analysis of sample entropy showed a significant interaction between pain/control and time (P

Thermomagnetic force acting on an ellipsoidal body immersed into a nonuniformly heated magnetic liquid

International Nuclear Information System (INIS)

Naletova, V.A.; Kvitantsev, A.S.

2002-01-01

A prolate spheroidal body immersed into a nonuniformly heated magnetic liquid in an applied magnetic field has been considered. The expressions for the pressure and velocity of the liquid, temperature and magnetic field have been obtained. The formula for a thermomagnetic force acting on the body has been calculated. It has been shown that the body shape needs to be taken into account when we study the thermomagnetic diffusion of the prolate bodies

The Ay puzzle and the nuclear force

International Nuclear Information System (INIS)

Hueber, D.

1999-01-01

The nucleon-deuteron analyzing power A y in elastic nucleon-deuteron scattering poses a longstanding puzzle. At energies E lab below approximately 30 MeV, A y cannot be described by any realistic NN force. The inclusion of existing three-nucleon forces does not improve the situation. Because of recent questions about the 3 P J NN phases, we examine whether reasonable changes in the NN force can resolve the puzzle. In order to do this, we investigate the effect on the 3 P J waves produced by changes in different parts of the potential (viz., the central force, tensor force, etc.), as well as on the 2-body observables and on A y . We find that it is not possible with reasonable changes in the NN potential to increase the 3-body A y , and at the same time to keep the 2-body observables unchanged. We therefore conclude that the A y puzzle is likely to be solved by new three-nucleon forces, such as those of spin-orbit type, which have not yet been taken into account. Refs. 7, tab. 1 (author)

Assessment of mechanical and three-body abrasive wear peculiarity ...

Indian Academy of Sciences (India)

The three-body abrasive wear characteristic of fabricated composites has been assessed under different operating conditions. For this, the three-body abrasion test is done on dry abrasion test rig (TR-50)and analysed using Taguchi's experimental design scheme and analysis of variance. The results obtained from these ...

Repulsive Casimir force in Bose–Einstein Condensate

Science.gov (United States)

Mehedi Faruk, Mir; Biswas, Shovon

2018-04-01

We study the Casimir effect for a three dimensional system of ideal free massive Bose gas in a slab geometry with Zaremba and anti-periodic boundary conditions. It is found that for these type of boundary conditions the resulting Casimir force is repulsive in nature, in contrast with usual periodic, Dirichlet or Neumann boundary condition where the Casimir force is attractive (Martin and Zagrebnov 2006 Europhys. Lett. 73 15). Casimir forces in these boundary conditions also maintain a power law decay function below condensation temperature and exponential decay function above the condensation temperature albeit with a positive sign, identifying the repulsive nature of the force.

Experiments and Large-Eddy Simulations of acoustically forced bluff-body flows

Energy Technology Data Exchange (ETDEWEB)

Ayache, S.; Dawson, J.R.; Triantafyllidis, A. [Department of Engineering, University of Cambridge (United Kingdom); Balachandran, R. [Department of Mechanical Engineering, University College London (United Kingdom); Mastorakos, E., E-mail: em257@eng.cam.ac.u [Department of Engineering, University of Cambridge (United Kingdom)

2010-10-15

The isothermal air flow behind an enclosed axisymmetric bluff body, with the incoming flow being forced by a loudspeaker at a single frequency and with large amplitude, has been explored with high data-rate Laser-Doppler Anemometry measurements and Large-Eddy Simulations. The comparison between experiment and simulations allows a quantification of the accuracy of LES for turbulent flows with periodicity and the results provide insights into the structure of flows relevant to combustors undergoing self-excited oscillations. At low forcing frequencies, the whole flow pulsates with the incoming flow, although at a phase lag that depends on spatial location. At high forcing frequencies, vortices are shed from the bluff body and the recirculation zone, as a whole, pulsates less. Despite the fact that the incoming flow has an oscillation that is virtually monochromatic, the velocity spectra show peaks at various harmonics, whose relative magnitudes vary with location. A sub-harmonic peak is also observed inside the recirculation zone possibly caused by merging of the shed vortices. The phase-averaged turbulent fluctuations show large temporal and spatial variations. The LES reproduces reasonably accurately the experimental findings in terms of phase-averaged mean and r.m.s. velocities, vortex formation, and spectral peaks.

Experiments and Large-Eddy Simulations of acoustically forced bluff-body flows

International Nuclear Information System (INIS)

Ayache, S.; Dawson, J.R.; Triantafyllidis, A.; Balachandran, R.; Mastorakos, E.

2010-01-01

The isothermal air flow behind an enclosed axisymmetric bluff body, with the incoming flow being forced by a loudspeaker at a single frequency and with large amplitude, has been explored with high data-rate Laser-Doppler Anemometry measurements and Large-Eddy Simulations. The comparison between experiment and simulations allows a quantification of the accuracy of LES for turbulent flows with periodicity and the results provide insights into the structure of flows relevant to combustors undergoing self-excited oscillations. At low forcing frequencies, the whole flow pulsates with the incoming flow, although at a phase lag that depends on spatial location. At high forcing frequencies, vortices are shed from the bluff body and the recirculation zone, as a whole, pulsates less. Despite the fact that the incoming flow has an oscillation that is virtually monochromatic, the velocity spectra show peaks at various harmonics, whose relative magnitudes vary with location. A sub-harmonic peak is also observed inside the recirculation zone possibly caused by merging of the shed vortices. The phase-averaged turbulent fluctuations show large temporal and spatial variations. The LES reproduces reasonably accurately the experimental findings in terms of phase-averaged mean and r.m.s. velocities, vortex formation, and spectral peaks.

Three-body and four-body photodisintegrations of the 4He nuclei in the Δ region

International Nuclear Information System (INIS)

Niki, Kazuaki

1991-01-01

The differential and total cross sections were measured for the three-body (pnd) and four-body (ppnn) final states in photodisintegration of 4 He in an energy range between 125 and 445 MeV. The kinematic variables were determined in an almost complete way, using a large acceptance spectrometer together with the use of tagged photons of an energy resolution of 10 MeV. We have found that the three-body reaction 4 He(γ, pn)d makes a dominant contribution among various processes which lead to non-mesonic final states. The behavior of the 4 He(γ, pn)d cross section is well described by the quasi-deuteron model (QDM). On the other hand, the four-body breakup cross sections are not consistent with the prediction of the QDM. For these four-body reactions, photon absorption by three-nucleon clusters seems to give a dominant effect. The four-body cross sections also show a broad enhancement around 300 to 400 MeV, indicating a possible participation of the Δ to the reactions. (author)

Three-body interactions and the Landau levels using Nikiforov ...

Indian Academy of Sciences (India)

In this article, the eigenvalues for the three-body interactions on the line and the Landau levels in the presence of topological defects have been regenerated by the Nikiforov–Uvarov (NU) method. Two exhaustive lists of such exactly solvable potentials are given. Keywords. Nikiforov–Uvarov (NU) method; three-body ...

The physics origin of the hierarchy of bodies in space

Science.gov (United States)

Bejan, A.; Wagstaff, R. W.

2016-03-01

Here we show that bodies of the same size suspended uniformly in space constitute a system (a "suspension") in a state of uniform volumetric tension because of mass-to-mass forces of attraction. The system "snaps" hierarchically, and evolves faster to a state of reduced tension when the bodies coalesce spontaneously nonuniformly, i.e., hierarchically, into few large and many small bodies suspended in the same space. Hierarchy, not uniformity, is the design that emerges, and it is in accord with the constructal law. The implications of this principle of physics in natural organization and evolution are discussed.

Structures of two-dimensional three-body systems

International Nuclear Information System (INIS)

Ruan, W.Y.; Liu, Y.Y.; Bao, C.G.

1996-01-01

Features of the structure of L = 0 states of a two-dimensional three-body model system have been investigated. Three types of permutation symmetry of the spatial part, namely symmetric, antisymmetric, and mixed, have been considered. A comparison has been made between the two-dimensional system and the corresponding three-dimensional one. The effect of symmetry on microscopic structures is emphasized. (author)

Efimov resonances in atomic three-body systems

International Nuclear Information System (INIS)

Mezei, J. Zs.; Papp, Z.

2006-01-01

In a recent work [Phys. Rev. Lett. 94, 143201 (2005)], we reported an accumulation of three-body resonant states attached to n=2 and higher two-body thresholds. A more careful investigation revealed that there are resonances of the same kind above the n=1 threshold as well. This suggests that the resonances attached to the thresholds are Efimov resonances

Three-body dynamics in one dimension: a test model for the three-nucleon system with irreducible pionic diagrams

International Nuclear Information System (INIS)

Melde, T.; Canton, L.; Svenne, J.P.

2002-01-01

We formulate the three-body problem in one dimension in terms of the (Faddeev-type) integral equation approach. As an application, we develop a spinless, one-dimensional (1-D) model that mimics three-nucleon dynamics in one dimension. Using simple two-body potentials that reproduce the deuteron binding, we obtain that the three-body system binds at about 7.5 MeV. We then consider two types of residual pionic corrections in the dynamical equation; one related to the 2π-exchange three-body diagram, the other to the 1π-exchange three-body diagram. We find that the first contribution can produce an additional binding effect of about 0.9 MeV. The second term produces smaller binding effects, which are, however, dependent on the uncertainty in the off-shell extrapolation of the two-body t-matrix. This presents interesting analogies with what occurs in three dimensions. The paper also discusses the general three-particle quantum scattering problem, for motion restricted to the fall line. (author)

Rules of Attraction

Science.gov (United States)

2004-01-01

This image composite shows two of the Mars Exploration Rover Opportunity's magnets, the 'capture' magnet (upper portion of left panel) and the 'filter' magnet (lower portion of left panel). Scientists use these tools to study the origins of martian dust in the atmosphere. The left panel was taken by the rover's panoramic camera. The four panels to the right, taken by the microscopic imager, show close-up views of the two magnets. The bull's-eye appearance of the capture magnet is a result of alternating magnetic fields, which are used to increase overall magnetic force. The filter magnet lacks these alternating fields and consequently produces a weaker magnetic force. This weaker force selectively attracts only strong magnetic particles. Scientists were surprised by the large dark particles on the magnets because airborne particles are smaller in size. They theorize that these spots might be aggregates of small particles that clump together in a magnetic field.

Three-dimensional frictionless contact between layered elastic bodies and incorporating sharp edges

Science.gov (United States)

Tordesillas, A. A.; Hill, J. M.

1991-07-01

The roller coating system used in industry to apply paint to sheet metal involves two contacting rolling cylinders, one of which is rubber covered and through which the sheet metal travels. Of particular concern in the industry is the effect of high pressures upon the flow of paint at the ends of the rollers. In an elastohydrodynamic-lubrication analysis of the paint flow, it is the corresponding “dry-contact pressure” which is of major concern. In this paper we present a numerical solution to the three-dimensional contact problem for both smooth profiled layered bodies and those which involve sharp edges but in both cases ignoring the effects of curvature. The procedure adopted is based on one previously developed by a number of authors for homogeneous bodies. An understanding of the consequences of changing the operating variables is of prime importance in an industrial scenario. The numerical scheme described here provides complete measurements of both the deformation and the contact pressure distribution for given operating variables, which are the elastic properties and dimensions of both rolls and the total applied force.

LAGRANGE SOLUTIONS TO THE DISCRETE-TIME GENERAL THREE-BODY PROBLEM

International Nuclear Information System (INIS)

Minesaki, Yukitaka

2013-01-01

There is no known integrator that yields exact orbits for the general three-body problem (G3BP). It is difficult to verify whether a numerical procedure yields the correct solutions to the G3BP because doing so requires knowledge of all 11 conserved quantities, whereas only six are known. Without tracking all of the conserved quantities, it is possible to show that the discrete general three-body problem (d-G3BP) yields the correct orbits corresponding to Lagrange solutions of the G3BP. We show that the d-G3BP yields the correct solutions to the G3BP for two special cases: the equilateral triangle and collinear configurations. For the triangular solution, we use the fact that the solution to the three-body case is a superposition of the solutions to the three two-body cases, and we show that the three bodies maintain the same relative distances at all times. To obtain the collinear solution, we assume a specific permutation of the three bodies arranged along a straight rotating line, and we show that the d-G3BP maintains the same distance ratio between two bodies as in the G3BP. Proving that the d-G3BP solutions for these cases are equivalent to those of the G3BP makes it likely that the d-G3BP and G3BP solutions are equivalent in other cases. To our knowledge, this is the first work that proves the equivalence of the discrete solutions and the Lagrange orbits.

The Temporal Stability of Lack of Sexual Attraction Across Young Adulthood.

Science.gov (United States)

Cranney, Stephen

2016-04-01

There is a large and growing literature on the stability of sexual orientation across the lifespan. However, virtually no studies have been conducted on the longitudinal stability of any dimension of asexuality. Here I utilized Kinsey scale-type data from Wave III and Wave IV of the Add Health survey to measure the stability of indicating "not sexually attracted to either males or females" in a forced-choice, Kinsey-type scale and during the time participants were moving through early adulthood (18-26 years in Wave III and 24-32 years in Wave IV). I found that, for the most part, individuals who reported no sexual attraction in Wave III were not the same individuals who reported no sexual attraction in Wave IV, with only three out of the 25 in Wave III who indicated no sexual attraction going on to do the same in Wave IV. This inter-wave consistency was lower than it was for other sexual minorities. However, indicating no sexual attraction in one wave was still a statistically significant predictor of indicating no sexual attraction in the other wave, as was refusing to answer or indicating the "don't know" option in the other wave. These findings do not necessarily denote change in sexual attraction across waves; the fact that not answering the question in one wave was a significant predictor of indicating no sexual attraction in the other wave provides quantitative evidence for the ambiguities involved in sexual identities when sexuality is taken for granted in the broader culture. This ambiguity affects the operationalization and quantification of asexuality.

General operator form of the non-local three-nucleon force

Energy Technology Data Exchange (ETDEWEB)

Topolnicki, K. [Jagiellonian University, M. Smoluchowski Institute of Physics, Krakow (Poland)

2017-09-15

This paper describes a procedure to obtain the general form of the three-nucleon force. The result is an operator form where the momentum space matrix element of the three-nucleon potential is written as a linear combination of 320 isospin-spin-momentum operators and scalar functions of momenta. Any spatial and isospin rotation invariant three-nucleon force can be written in this way and in order for the potential to be Hermitian, symmetric under parity inversion, time reversal and particle exchange, the scalar functions must have definite transformation properties under these discrete operations. A complete list of the isospin-spin-momentum operators and scalar function transformation properties is given. (orig.)

Direction-specific van der Waals attraction between rutile TiO ₂ nanocrystals

Energy Technology Data Exchange (ETDEWEB)

Zhang, Xin; He, Yang; Sushko, Maria L.; Liu, Jia; Luo, Langli; De Yoreo, James J.; Mao, Scott X.; Wang, Chongmin; Rosso, Kevin M.

2017-04-27

Mutual lattice orientations dictate the types and magnitudes of forces between crystalline particles. When lattice polarizability is anisotropic, the van der Waals dispersion attraction can, in principle, contribute to this direction dependence. Here we report direct measurement of this attraction between rutile nanocrystals, as a function of their mutual orientation and surface hydration extent. At tens of nanometers of separation the attraction is weak and shows no dependence on azimuthal alignment nor surface hydration. At separations of approximately one hydration layer the attraction is strongly dependent on azimuthal alignment, and systematically decreases as intervening water density increases. Measured forces are in close agreement with predictions from Lifshitz theory, and show that dispersion forces are capable of generating a torque between particles interacting in solution and between grains in materials.

Sn and three-body forces

Indian Academy of Sciences (India)

. We have used the CD-Bonn potential-based realistic CWG [10] and the empirical ..... In another experiment, delayed γ-ray cascades, originating from the decay of isomeric .... 7/2 partition contributing ≃79–80% in SMPN/CWG3M calculations.

Drawing and using free body diagrams: Why it may be better not to decompose forces

Directory of Open Access Journals (Sweden)

Ivica Aviani

2015-12-01

Full Text Available In this study we investigated how two different approaches to drawing free body diagrams influence the development of students’ understanding of Newton’s laws, including their ability to identify real forces. For this purpose we developed a 12-item two-tier multiple choice survey and conducted a quasiexperiment. This experiment included two groups of first-year physics students from Rijeka (RG (n_{e}=27 and Split (SG (n_{c}=25 Universities. Students from both groups solved mechanics problems for a period of two class hours. The only difference was that RG students used the superposition of forces approach to solving mechanics problems and in SG the decomposition of forces approach has been used. The ANCOVA (n_{c}=17, n_{e}=17 showed a statistically significant difference in favor of RG, whereby the effect sizes were moderate to large, and the largest differences have been observed in the ability of identifying real forces. Students from the control group (SG more often exhibited the misconception that forces and their components act on a body independently and simultaneously. Our results support the idea that the practice of resolving forces into the components may not be the most effective way to develop understanding of Newton’s laws and the concept of force.

Comparison of lumbar force between pubertal and post-pubertal adolescents: interference of physical growth, body fat and lifestyle.

Directory of Open Access Journals (Sweden)

Mikael Seabra Moraes

2018-01-01

Full Text Available Abstract Aim: To compare performance in the lumbar force test in pubertal and post-pubertal adolescents by controlling the interference of physical growth, body fat, screen time and physical activity. Methods: A cross-sectional study with 933 adolescents (492 girls aged 14-19 from the city of São José, Brazil. Lumbar strength was assessed using the isometric lumbar extension test proposed by the Canadian Society of Exercise Physiology. Sexual maturation was classified according to Tanner’s criteria. Physical growth variables (age, body weight, stature, BMI, body fat (triceps and subscapular skinfolds, sedentary behavior based on screen time and overall physical activity were controlled in the Analysis of Covariance (ANCOVA, with a significance level of 5%. Results: Post-pubertal boys presented higher lumbar force compared to pubertal ones only when interference of BMI, body fat, screen time and physical activity was controlled. Pubertal girls presented higher lumbar force compared to post-pubertal ones, both when controlling the analysis for the studied variables and when not controlled by them. Conclusion: BMI, body fat, screen time and physical activity interfere in the difference in lumbar strength of boys, in which post-pubertal boys presented better performance in lumbar force compared to pubertal ones. Regardless of interference or not of these variables, pubertal girls presented better performance in lumbar force when compared to post-pubertal ones.

The role of atomic level steric effects and attractive forces in protein folding.

Science.gov (United States)

Lammert, Heiko; Wolynes, Peter G; Onuchic, José N

2012-02-01

Protein folding into tertiary structures is controlled by an interplay of attractive contact interactions and steric effects. We investigate the balance between these contributions using structure-based models using an all-atom representation of the structure combined with a coarse-grained contact potential. Tertiary contact interactions between atoms are collected into a single broad attractive well between the C(β) atoms between each residue pair in a native contact. Through the width of these contact potentials we control their tolerance for deviations from the ideal structure and the spatial range of attractive interactions. In the compact native state dominant packing constraints limit the effects of a coarse-grained contact potential. During folding, however, the broad attractive potentials allow an early collapse that starts before the native local structure is completely adopted. As a consequence the folding transition is broadened and the free energy barrier is decreased. Eventually two-state folding behavior is lost completely for systems with very broad attractive potentials. The stabilization of native-like residue interactions in non-perfect geometries early in the folding process frequently leads to structural traps. Global mirror images are a notable example. These traps are penalized by the details of the repulsive interactions only after further collapse. Successful folding to the native state requires simultaneous guidance from both attractive and repulsive interactions. Copyright © 2011 Wiley Periodicals, Inc.

Three-body Coulomb breakup of 11Li in the complex scaling method

International Nuclear Information System (INIS)

Myo, Takayuki; Aoyama, Shigeyoshi; Kato, Kiyoshi; Ikeda, Kiyomi

2003-01-01

Coulomb breakup strengths of 11 Li into a three-body 9 Li+n+n system are studied in the complex scaling method. We decompose the transition strengths into the contributions from three-body resonances, two-body '' 10 Li+n'' and three-body '' 9 Li+n+n'' continuum states. In the calculated results, we cannot find the dipole resonances with a sharp decay width in 11 Li. There is a low energy enhancement in the breakup strength, which is produced by both the two- and three-body continuum states. The enhancement given by the three-body continuum states is found to have a strong connection to the halo structure of 11 Li. The calculated breakup strength distribution is compared with the experimental data from MSU, RIKEN and GSI

A novel integrated multifunction micro-sensor for three-dimensional micro-force measurements.

Science.gov (United States)

Wang, Weizhong; Zhao, Yulong; Qin, Yafei

2012-01-01

An integrated multifunction micro-sensor for three-dimensional micro-force precision measurement under different pressure and temperature conditions is introduced in this paper. The integrated sensor consists of three kinds of sensors: a three-dimensional micro-force sensor, an absolute pressure sensor and a temperature sensor. The integrated multifunction micro-sensor is fabricated on silicon wafers by micromachining technology. Different doping doses of boron ion, placement and structure of resistors are tested for the force sensor, pressure sensor and temperature sensor to minimize the cross interference and optimize the properties. A glass optical fiber, with a ladder structure and sharp tip etched by buffer oxide etch solution, is glued on the micro-force sensor chip as the tactile probe. Experimental results show that the minimum force that can be detected by the force sensor is 300 nN; the lateral sensitivity of the force sensor is 0.4582 mV/μN; the probe length is linearly proportional to sensitivity of the micro-force sensor in lateral; the sensitivity of the pressure sensor is 0.11 mv/KPa; the sensitivity of the temperature sensor is 5.836 × 10(-3) KΩ/°C. Thus it is a cost-effective method to fabricate integrated multifunction micro-sensors with different measurement ranges that could be used in many fields.

A Novel Integrated Multifunction Micro-Sensor for Three-Dimensional Micro-Force Measurements

Directory of Open Access Journals (Sweden)

Yafei Qin

2012-03-01

Full Text Available An integrated multifunction micro-sensor for three-dimensional micro-force precision measurement under different pressure and temperature conditions is introduced in this paper. The integrated sensor consists of three kinds of sensors: a three-dimensional micro-force sensor, an absolute pressure sensor and a temperature sensor. The integrated multifunction micro-sensor is fabricated on silicon wafers by micromachining technology. Different doping doses of boron ion, placement and structure of resistors are tested for the force sensor, pressure sensor and temperature sensor to minimize the cross interference and optimize the properties. A glass optical fiber, with a ladder structure and sharp tip etched by buffer oxide etch solution, is glued on the micro-force sensor chip as the tactile probe. Experimental results show that the minimum force that can be detected by the force sensor is 300 nN; the lateral sensitivity of the force sensor is 0.4582 mV/μN; the probe length is linearly proportional to sensitivity of the micro-force sensor in lateral; the sensitivity of the pressure sensor is 0.11 mv/KPa; the sensitivity of the temperature sensor is 5.836 × 10−3 KΩ/°C. Thus it is a cost-effective method to fabricate integrated multifunction micro-sensors with different measurement ranges that could be used in many fields.

A moving control volume method for smooth computation of hydrodynamic forces and torques on immersed bodies

Science.gov (United States)

Nangia, Nishant; Patankar, Neelesh A.; Bhalla, Amneet P. S.

2017-11-01

Fictitious domain methods for simulating fluid-structure interaction (FSI) have been gaining popularity in the past few decades because of their robustness in handling arbitrarily moving bodies. Often the transient net hydrodynamic forces and torques on the body are desired quantities for these types of simulations. In past studies using immersed boundary (IB) methods, force measurements are contaminated with spurious oscillations due to evaluation of possibly discontinuous spatial velocity of pressure gradients within or on the surface of the body. Based on an application of the Reynolds transport theorem, we present a moving control volume (CV) approach to computing the net forces and torques on a moving body immersed in a fluid. The approach is shown to be accurate for a wide array of FSI problems, including flow past stationary and moving objects, Stokes flow, and high Reynolds number free-swimming. The approach only requires far-field (smooth) velocity and pressure information, thereby suppressing spurious force oscillations and eliminating the need for any filtering. The proposed moving CV method is not limited to a specific IB method and is straightforward to implement within an existing parallel FSI simulation software. This work is supported by NSF (Award Numbers SI2-SSI-1450374, SI2-SSI-1450327, and DGE-1324585), the US Department of Energy, Office of Science, ASCR (Award Number DE-AC02-05CH11231), and NIH (Award Number HL117163).

Contact parameters in two dimensions for general three-body systems

DEFF Research Database (Denmark)

F. Bellotti, F.; Frederico, T.; T. Yamashita, M.

2014-01-01

a subsystem is composed of two identical non-interacting particles. We also show that the three-body contact parameter is negligible in the case of one non-interacting subsystem compared to the situation where all subsystem are bound. As example, we present results for mixtures of Lithium with two Cesium......We study the two dimensional three-body problem in the general case of three distinguishable particles interacting through zero-range potentials. The Faddeev decomposition is used to write the momentum-space wave function. We show that the large-momentum asymptotic spectator function has the same...... to obtain two- and three-body contact parameters. We specialize from the general cases to examples of two identical, interacting or non-interacting, particles. We find that the two-body contact parameter is not a universal constant in the general case and show that the universality is recovered when...

Impacts of exposure to images of ideal bodies on male body dissatisfaction: a review.

Science.gov (United States)

Blond, Anna

2008-09-01

Research suggests that young men's body dissatisfaction increases when they see images of attractive muscular men. This article provides the first extensive review of experimental studies exposing men to advertisements or commercials featuring idealized male bodies. Impacts on body dissatisfaction were evaluated by calculating and analyzing effect sizes from 15 studies. The effect sizes indicate that exposure to images of idealized male bodies has a small but statistically significant negative impact on men's body dissatisfaction. Three studies suggest that young men who are dissatisfied with their bodies are at increased risk for negative self-evaluations when exposed to idealized images. Two studies suggest that men who are satisfied with their bodies may be protected against negative impacts from seeing such images.

FaCE: a tool for Three Body Faddeev calculations with core excitation

OpenAIRE

Thompson, I. J.; Nunes, F. M.; Danilin, B. V.

2004-01-01

FaCE is a self contained programme, with namelist input, that solves the three body Faddeev equations. It enables the inclusion of excitation of one of the three bodies, whilst the other two remain inert. It is particularly useful for obtaining the binding energies and bound state structure compositions of light exotic nuclei treated as three-body systems, given the three effective two body interactions. A large variety of forms for these interactions may be defined, and supersymmetric transf...

Analytical treatment of Coriolis coupling for three-body systems

Energy Technology Data Exchange (ETDEWEB)

Poirier, Bill

2005-01-31

In a previous article [J. Chem. Phys. 108 (1998) 5216], an efficient method was presented for performing 'exact' quantum calculations for the three-body rovibrational Hamiltonian, within the helicity-conserving approximation. This approach makes use of a certain three-body ''effective potential,'' enabling the same bend angle basis set to be employed for all values of the rotational quantum numbers, J, K and M. In the present work, the method is extended to incorporate Coriolis coupling, for which the relevant matrix elements are derived exactly. These can be used to solve the full three-body rovibrational problem, in the standard Jacobi coordinate vector embedding. Generalization of the method for coupled kinetic energy operators arising from other coordinate systems, embeddings, and/or system sizes, is also discussed.

Creating beauty: creativity compensates for low physical attractiveness when individuals assess the attractiveness of social and romantic partners.

Science.gov (United States)

Watkins, Christopher D

2017-04-01

Although creativity is attractive in a potential mate, it is unclear (i) whether the effects of creativity on attractiveness generalize to other social contexts and (ii) whether creativity has equivalent effects on men's and women's attractiveness. As social knowledge of creativity may either enhance or 'offset' the appeal of social partners who differ in physical attractiveness, three repeated measures experiments were conducted to directly address these issues. Here, participants rated a series of face-text pairs for attractiveness on trials that differed in one of four combinations of facial attractiveness (attractive and less attractive) and creativity (creative and less creative), rating story-tellers in two experiments (short interpretations of an identical painting) and creative ideas in a further experiment (alternative uses for an everyday object). Regardless of the sex of the judge, creativity and facial attractiveness had independent effects on men's overall attractiveness (initial experiment) and, in further experiments, more substantial effects on the attractiveness of men with less attractive faces than men with attractive faces (when using a different measure of creativity) and specific effects on the attractiveness of individuals with less attractive faces (when using different face stimuli). Collectively, across three experiments, these findings suggest that creativity may compensate for putative cues to lower biological 'quality' and that the benefits of creativity to social groups more generally enhance attraction to creative men (in two experiments) and creative men and women (one experiment). More broadly, the data suggest that species can integrate knowledge of cognitive intelligence with visual cues to biological 'quality' to facilitate mate and/or ally choice.

Mechanical evidence that flamingos can support their body on one leg with little active muscular force.

Science.gov (United States)

Chang, Young-Hui; Ting, Lena H

2017-05-01

Flamingos (Phoenicopteridae) often stand and sleep on one leg for long periods, but it is unknown how much active muscle contractile force they use for the mechanical demands of standing on one leg: body weight support and maintaining balance. First, we demonstrated that flamingo cadavers could passively support body weight on one leg without any muscle activity while adopting a stable, unchanging, joint posture resembling that seen in live flamingos. By contrast, the cadaveric flamingo could not be stably held in a two-legged pose, suggesting a greater necessity for active muscle force to stabilize two-legged versus one-legged postures. Our results suggest that flamingos engage a passively engaged gravitational stay apparatus (proximally located) for weight support during one-legged standing. Second, we discovered that live flamingos standing on one leg have markedly reduced body sway during quiescent versus alert behaviours, with the point of force application directly under the distal joint, reducing the need for muscular joint torque. Taken together, our results highlight the possibility that flamingos stand for long durations on one leg without exacting high muscular forces and, thus, with little energetic expenditure. © 2017 The Author(s).

CTBC. A program to solve the collinear three-body Coulomb problem. Bound states and scattering below the three-body disintegration threshold

International Nuclear Information System (INIS)

Tolstikhin, Oleg I.; Namba, Chusei

2003-08-01

A program to solve the quantum-mechanical collinear three-body Coulomb problem is described and illustrated by calculations for a number of representative systems and processes. In the internal region, the Schroedinger equation is solved in hyperspherical coordinates using the slow/smooth variable discretization method. In asymptotic regions, the solution is obtained in Jacobi coordinates using the asymptotic package GAILIT from the CPC library. Only bound states and scattering processes below the three-body disintegration threshold are considered here; resonances and fragmentation processes will be discussed in subsequent parts of this series. (author)

Attracting International Hotels

DEFF Research Database (Denmark)

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

2015-01-01

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...... 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...... 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....

A levitation force and magnetic field distribution measurement system in three dimensions

International Nuclear Information System (INIS)

Yang, W.M.; Chao, X.X.; Shu, Z.B.; Zhu, S.H.; Wu, X.L.; Bian, X.B.; Liu, P.

2006-01-01

A levitation force and magnetic field distribution measurement system in three dimension has been designed and constructed, which can be used for the levitation force measurement between a superconductor and a magnet, or magnet to magnet in three dimensions; and for the measurement of magnetic field distribution in three dimensions according to your need in space. It can also give out the dynamical changing result of magnetic field density with time during levitation force measurement. If we change the sensor of the detector of the measurement system, it also can be used for other kinds of measurement of physical properties. It is a good device for the measurement of magnetic properties of materials. In addition the device can also be used to work at carving in three dimensions

Three-Body Antikaon-Nucleon Systems

Czech Academy of Sciences Publication Activity Database

Shevchenko, Nina V.

2017-01-01

Roč. 58, č. 1 (2017), č. článku UNSP 6. ISSN 0177-7963 R&D Projects: GA ČR(CZ) GA15-04301S Institutional support: RVO:61389005 Keywords : three-body * antikaon-nucleon * K p interactions Subject RIV: BE - Theoretical Physics OBOR OECD: Atom ic, molecular and chemical physics (physics of atom s and molecules including collision, interaction with radiation, magnetic resonances, Mössbauer effect) Impact factor: 0.877, year: 2016

Particle attraction effects on the centrifugal casting and extrusion of alumina

International Nuclear Information System (INIS)

Schilling, C.H.; Bergstroem, L.; Ker, H.L.; Aksay, I.A.

1993-01-01

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

The mass-damped Riemann problem and the aerodynamic surface force calculation for an accelerating body

International Nuclear Information System (INIS)

Tan, Zhiqiang; Wilson, D.; Varghese, P.L.

1997-01-01

We consider an extension of the ordinary Riemann problem and present an efficient approximate solution that can be used to improve the calculations of aerodynamic forces on an accelerating body. The method is demonstrated with one-dimensional examples where the Euler equations and the body motion are solved in the non-inertial co-ordinate frame fixed to the accelerating body. 8 refs., 6 figs

Random three-dimensional jammed packings of elastic shells acting as force sensors

Science.gov (United States)

Jose, Jissy; van Blaaderen, Alfons; Imhof, Arnout

2016-06-01

In a jammed solid of granular particles, the applied stress is in-homogeneously distributed within the packing. A full experimental characterization requires measurement of all the interparticle forces, but so far such measurements are limited to a few systems in two and even fewer in three dimensions. Particles with the topology of (elastic) shells are good local force sensors as relatively large deformations of the shells result from relatively small forces. We recently introduced such fluorescent shells as a model granular system in which force distributions can be determined in three dimensions using confocal microscopy and quantitative image analysis. An interesting aspect about these shells that differentiates them from other soft deformable particles is their buckling behavior at higher compression. This leads to deformations that do not conserve the inner volume of the particle. Here we use this system to accurately measure the contact forces in a three-dimensional packing of shells subjected to a static anisotropic compression and to shear. At small deformations forces are linear, however, for a buckled contact, the restoring force is related to the amount of deformation by a square root law, as follows from the theory of elasticity of shells. Near the unjamming-jamming transition (point J ), we found the probability distribution of the interparticle forces P (f ) to decay nearly exponentially at large forces, with little evidence of long-range force chains in the packings. As the packing density is increased, the tail of the distribution was found to crossover to a Gaussian, in line with other experimental and simulation studies. Under a small shear strain, up to 0.216, applied at an extremely low shear rate, we observed a shear-induced anisotropy in both the pair correlation function and contact force network; however, no appreciable change was seen in the number of contacts per particle.

Efimov three-body states on top of a Fermi sea

International Nuclear Information System (INIS)

Nygaard, Nicolai Gayle; Zinner, Nikolaj Thomas

2014-01-01

The stabilization of Cooper pairs of bound electrons in the background of a Fermi sea is the origin of superconductivity and the paradigmatic example of the striking influence of many-body physics on few-body properties. In the quantum-mechanical three-body problem the famous Efimov effect yields unexpected scaling relations among a tower of universal states. These seemingly unrelated problems can now be studied in the same setup thanks to the success of ultracold atomic gas experiments. In light of the tremendous effect of a background Fermi sea on two-body properties, a natural question is whether a background can modify or even destroy the Efimov effect. Here we demonstrate how the generic problem of three interacting particles changes when one particle is embedded in a background Fermi sea, and show that Efimov scaling persists. It is found in a scaling that relates the three-body physics to the background density of fermionic particles

The effects of attractive vs. repulsive instructional cuing on balance performance.

Science.gov (United States)

Kinnaird, Catherine; Lee, Jaehong; Carender, Wendy J; Kabeto, Mohammed; Martin, Bernard; Sienko, Kathleen H

2016-03-16

Torso-based vibrotactile feedback has been shown to improve postural performance during quiet and perturbed stance in healthy young and older adults and individuals with balance impairments. These systems typically include tactors distributed around the torso that are activated when body motion exceeds a predefined threshold. Users are instructed to "move away from the vibration". However, recent studies have shown that in the absence of instructions, vibrotactile stimulation induces small (~1°) non-volitional responses in the direction of its application location. It was hypothesized that an attractive cuing strategy (i.e., "move toward the vibration") could improve postural performance by leveraging this natural tendency. Eight healthy older adults participated in two non-consecutive days of computerized dynamic posturography testing while wearing a vibrotactile feedback system comprised of an inertial measurement unit and four tactors that were activated in pairs when body motion exceeded 1° anteriorly or posteriorly. A crossover design was used. On each day participants performed 24 repetitions of Sensory Organization Test condition 5 (SOT5), three repetitions each of SOT 1-6, three repetitions of the Motor Control Test, and five repetitions of the Adaptation Test. Performance metrics included A/P RMS, Time-in-zone and 95 % CI Ellipse. Performance improved with both cuing strategies but participants performed better when using repulsive cues. However, the rate of improvement was greater for attractive versus repulsive cuing. The results suggest that when the cutaneous signal is interpreted as an alarm, cognition overrides sensory information. Furthermore, although repulsive cues resulted in better performance, attractive cues may be as good, if not better, than repulsive cues following extended training.

Efimov Physics and the Three-Body Parameter within a Two-Channel Framework

DEFF Research Database (Denmark)

Sørensen, Peder Klokmose; V. Fedorov, D.; S. Jensen, A.

2012-01-01

scaling laws. We recover known results for broad Feshbach resonances with small effective range, whereas in the case of narrow resonances we find a distinct non-monotonic behavior of the threshold at which the lowest Efimov trimer merges with the three-body continuum. To address the issue of the physical...... origin of the three-body parameter we provide a physically clear model for the relation between three-body physics and typical two-body atom-atom interactions. Our results demonstrate that experimental information from narrow Feshbach resonances and/or mixed systems are of vital importance to pin down...... the relation of two- and three-body physics in atomic systems....

Effects of adding whole body vibration to squat training on isometric force/time characteristics.

Science.gov (United States)

Lamont, Hugh S; Cramer, Joel T; Bemben, Debra A; Shehab, Randa L; Anderson, Mark A; Bemben, Michael G

2010-01-01

Resistance training interventions aimed at increasing lower-body power and rates of force development have produced varying results. Recent studies have suggested that whole-body low-frequency vibration (WBLFV) may elicit an acute postactivation potentiation response, leading to acute improvements in power and force development. Potentially, the use of WBLFV between sets of resistance training rather than during training itself may lead to increased recruitment and synchronization of high-threshold motor units, minimize fatigue potential, and facilitate the chronic adaptation to resistance exercise. The purpose of this study was to determine the effects of applying TriPlaner, WBLFV, prior to and then intermittently between sets of Smith machine squats on short-term adaptations in explosive isometric force expression. Thirty recreationally resistance trained men aged 18-30 were randomly assigned to 1 of 3 groups: resistance training only (SQT, n = 11), resistance plus whole-body vibration (SQTV, n = 13), or active control (CON, n = 6). An isometric squat test was performed prior to and following a 6-week periodized Smith machine squat program. Whole-body low-frequency vibration was applied 180 seconds prior to the first work set (50 Hz, 2-4 mm, 30 seconds) and intermittently (50 Hz, 4-6 mm, 3 x 10 seconds, 60 seconds between exposures) within a 240-second interset rest period. Subjects were instructed to assume a quarter squat posture while positioning their feet directly under their center of mass, which was modified using a handheld goniometer to a knee angle of 135 +/- 5 degrees . Instructions were given to subjects to apply force as fast and as hard as possible for 3.5 seconds. Isometric force (N) and rates of force development (N.s(-1)) were recorded from the onset of contraction (F(0)) to time points corresponding to 30, 50, 80, 100, 150, and 250 milliseconds, as well as the peak isometric rate of force development (PISORFD), and rate of force development to

Visual exposure to obesity: Experimental effects on attraction toward overweight men and mate choice in females.

Science.gov (United States)

Robinson, E; Christiansen, P

2015-09-01

Cultural differences in ideal body weight are well established, but less research has examined attraction toward potential mates of heavier body weights. We examined whether exposure to obesity increases physical attraction toward overweight men. In Studies 1 and 2, we examined the effect that exposure to obese vs healthy weight men had on female attraction toward an overweight man. Study 3 examined whether females who are regularly exposed to males of heavier body weights reported a greater attraction toward overweight men. Study 4 tested whether females in an online dating study were more likely to choose to date an overweight man, after having been exposed to obesity. Exposure to obesity altered visual perceptions of what normal and therefore healthy body weights were and this resulted in greater attraction toward an overweight man (Studies 1 and 2). Females regularly exposed to men of heavier body weight reported a greater attraction toward overweight men (Study 3). After exposure to obesity, females in an online dating study were more likely to choose to date an overweight man ahead of a healthy weight man (Study 4). Exposure to male obesity increases female attraction toward overweight men and may affect mate choice.

Some highlights in few-body nuclear physics.

Energy Technology Data Exchange (ETDEWEB)

Holt, R. J.

2000-12-07

During the past five years, there have been tremendous advances in both experiments and theoretical calculations in few-body nuclear systems. Advances in technology have permitted experiments of unprecedented accuracy. Jefferson Laboratory has begun operation and the first round of experimental results have become available. New polarization techniques have been exploited at a number of laboratories, in particular, at Jefferson Lab, IUCF, RIKEN, NIKHEF, Mainz, MIT-Bates and HERMES. Some of these results will be shown here. In addition, there have been tremendous advances in few-body theory. Five modern two-nucleon potentials have which describe the nucleon-nucleon data extremely well have become available. A standard model of nuclear physics based on these two nucleon potentials as well as modern three-nucleon forces has emerged. This standard model has enjoyed tremendous success in the few body systems. Exact three-body calculations have been extended into the continuum in order to take full advantage of scattering data in advancing our understanding of the the few-nucleon system. In addition, the application of chiral symmetry has become an important constraint on nucleon-nucleon as well as three-nucleon forces. As a result of all these efforts, we have seen rapid developments in the three-body force. Despite these advances, there remain some extremely important open issues: (1) What is the role of quarks and gluons in nuclear structure; (2) Can we distinguish meson exchange from quark interchange; (3) Is few-body theory sufficient to describe simultaneously the mass 2, 3 and 4 form factors; (4) What is the isospin and spin dependence of the three-body force; (5) Are there medium modifications for nucleons and mesons in nuclei; (6) Is there an enhancement of antiquarks or pions in nuclei related to the binding; and (7) Are short range correlations observable in nuclei? In this paper the author summarizes the status of our understanding of these issues.

Force sensing using 3D displacement measurements in linear elastic bodies

Science.gov (United States)

Feng, Xinzeng; Hui, Chung-Yuen

2016-07-01

In cell traction microscopy, the mechanical forces exerted by a cell on its environment is usually determined from experimentally measured displacement by solving an inverse problem in elasticity. In this paper, an innovative numerical method is proposed which finds the "optimal" traction to the inverse problem. When sufficient regularization is applied, we demonstrate that the proposed method significantly improves the widely used approach using Green's functions. Motivated by real cell experiments, the equilibrium condition of a slowly migrating cell is imposed as a set of equality constraints on the unknown traction. Our validation benchmarks demonstrate that the numeric solution to the constrained inverse problem well recovers the actual traction when the optimal regularization parameter is used. The proposed method can thus be applied to study general force sensing problems, which utilize displacement measurements to sense inaccessible forces in linear elastic bodies with a priori constraints.

Precision measurement of the Casimir-Lifshitz force in a fluid

International Nuclear Information System (INIS)

Munday, J. N.; Capasso, Federico

2007-01-01

The Casimir force, which results from the confinement of the quantum-mechanical zero-point fluctuations of electromagnetic fields, has received significant attention in recent years for its effect on micro- and nanoscale mechanical systems. With few exceptions, experimental observations have been limited to interacting conductive bodies separated by vacuum or air. However, interesting phenomena, including repulsive forces, are expected to exist in certain circumstances between metals and dielectrics when the intervening medium is not vacuum. In order to better understand the effect of the Casimir force in such situations and to test the robustness of the generalized Casimir-Lifshitz theory, we have performed precision measurements of the Casimir force between two metals immersed in a fluid. For this situation, the measured force is attractive and is approximately 80% smaller than the force predicted by Casimir for ideal metals in vacuum. We present experimental results and find them to be consistent with Lifshitz's theory

Effects of forcing in three-dimensional turbulent flows

NARCIS (Netherlands)

Biferale, L.; Lanotte, A.; Toschi, F.

2004-01-01

We present the results of a numerical investigation of three-dimensional homogeneous and isotropic turbulence, stirred by a random forcing with a power-law spectrum, Ef(k)~k3-y. Numerical simulations are performed at different resolutions up to 5123. We show that at varying the spectrum slope y,

Force-Velocity Relationship of Upper Body Muscles: Traditional Versus Ballistic Bench Press.

Science.gov (United States)

García-Ramos, Amador; Jaric, Slobodan; Padial, Paulino; Feriche, Belén

2016-04-01

This study aimed to (1) evaluate the linearity of the force-velocity relationship, as well as the reliability of maximum force (F0), maximum velocity (V0), slope (a), and maximum power (P0); (2) compare these parameters between the traditional and ballistic bench press (BP); and (3) determine the correlation of F0 with the directly measured BP 1-repetition maximum (1RM). Thirty-two men randomly performed 2 sessions of traditional BP and 2 sessions of ballistic BP during 2 consecutive weeks. Both the maximum and mean values of force and velocity were recorded when loaded by 20-70% of 1RM. All force-velocity relationships were strongly linear (r > .99). While F0 and P0 were highly reliable (ICC: 0.91-0.96, CV: 3.8-5.1%), lower reliability was observed for V0 and a (ICC: 0.49-0.81, CV: 6.6-11.8%). Trivial differences between exercises were found for F0 (ES: velocity relationship is useful to assess the upper body maximal capabilities to generate force, velocity, and power.

Status hierarchy, attractiveness hierarchy and sex ratio : Three contextual factors explaining the status-aggression link among adolescents

NARCIS (Netherlands)

Zwaan, Michiel; Dijkstra, Jan; Veenstra, René

The moderating effects of three specific conditions (status hierarchy, attractiveness hierarchy and sex ratio) on the link between status (popularity) and physical and relational aggression were examined in a large sample of adolescent boys (N = 1,665) and girls (N = 1,637) (M age = 13.60). In line

Three-body recombination of cold fermionic atoms

International Nuclear Information System (INIS)

Suno, H; Esry, B D; Greene, Chris H

2003-01-01

Recombination of identical, spin-polarized fermions in cold three-body collisions is investigated. We parametrize the mechanisms for recombination in terms of the 'scattering volume' V p and another length scale r 0 . Model two-body interactions were used within the framework of the adiabatic hyperspherical representation. We examine the recombination rate K 3 as a function of the collision energy E for various values of V p . Not only do we consider the dominant J Π = 1 + case, but also the next-leading order contributions from J Π = 1 - and 3 - . We discuss the behaviour near a two-body resonance and the expected universality of fermionic recombination. Comparisons with boson recombination are considered in detail

Electromagnetic reactions of few-body systems with the Lorentz integral transform method

International Nuclear Information System (INIS)

Leidemann, W.

2007-01-01

Various electromagnetic few-body break-up reactions into the many-body continuum are calculated microscopically with the Lorentz integral transform (LIT) method. For three- and four-body nuclei the nuclear Hamiltonian includes two- and three-nucleon forces, while semirealistic interactions are used in case of six- and seven-body systems. Comparisons with experimental data are discussed. In addition various interesting aspects of the 4 He photodisintegration are studied: investigation of a tetrahedrical symmetry of 4 He and a test of non-local nuclear force models via the induced two-body currents

Three-dimensional scanning force/tunneling spectroscopy at room temperature

International Nuclear Information System (INIS)

Sugimoto, Yoshiaki; Ueda, Keiichi; Abe, Masayuki; Morita, Seizo

2012-01-01

We simultaneously measured the force and tunneling current in three-dimensional (3D) space on the Si(111)-(7 × 7) surface using scanning force/tunneling microscopy at room temperature. The observables, the frequency shift and the time-averaged tunneling current were converted to the physical quantities of interest, i.e. the interaction force and the instantaneous tunneling current. Using the same tip, the local density of states (LDOS) was mapped on the same surface area at constant height by measuring the time-averaged tunneling current as a function of the bias voltage at every lateral position. LDOS images at negative sample voltages indicate that the tip apex is covered with Si atoms, which is consistent with the Si-Si covalent bonding mechanism for AFM imaging. A measurement technique for 3D force/current mapping and LDOS imaging on the equivalent surface area using the same tip was thus demonstrated. (paper)

Status Hierarchy, Attractiveness Hierarchy and Sex Ratio: Three Contextual Factors Explaining the Status-Aggression Link among Adolescents

Science.gov (United States)

Zwaan, Michiel; Dijkstra, Jan Kornelis; Veenstra, Rene

2013-01-01

The moderating effects of three specific conditions (status hierarchy, attractiveness hierarchy and sex ratio) on the link between status (popularity) and physical and relational aggression were examined in a large sample of adolescent boys ("N" = 1,665) and girls ("N" = 1,637) ("M" age = 13.60). In line with the…

A multi-electrode and pre-deformed bilayer spring structure electrostatic attractive MEMS actuator with large stroke at low actuation voltage

International Nuclear Information System (INIS)

Hu, Fangrong; Li, Zhi; Xiong, Xianming; Niu, Junhao; Peng, Zhiyong; Qian, Yixian; Yao, Jun

2012-01-01

This paper presents a multi-electrode and pre-deformed bilayer spring structure electrostatic attractive microelectromechanical systems (MEMS) actuator; it has large stroke at relatively low actuation voltage. Generally, electrostatic-attractive-force-based actuators have small stroke due to the instability resulted from the electrostatic ‘pull-in’ phenomenon. However, in many applications, the electrostatic micro-actuator with large stroke at low voltage is more preferred. By introducing a multi-electrode and a pre-deformed bilayer spring structure, an electrostatic attractive MEMS actuator with large stroke at very low actuation voltage has been successfully demonstrated in this paper. The actuator contains a central plate with a size of 300 µm × 300 µm × 1.5 µm and it is supported by four L-shaped bilayer springs which are pre-deformed due to residual stresses. Each bilayer spring is simultaneously attracted by three adjacent fixed electrodes, and the factors affecting the electrostatic attractive force are analyzed by a finite element analysis method. The prototype of the actuator is fabricated by poly-multi-user-MEMS-process (PolyMUMP) and the static performance is tested using a white light interferometer. The measured stroke of the actuator reaches 2 µm at 13 V dc, and it shows a good agreement with the simulation. (paper)

A novel three-filament model of force generation in eccentric contraction of skeletal muscles.

Directory of Open Access Journals (Sweden)

Gudrun Schappacher-Tilp

Full Text Available We propose and examine a three filament model of skeletal muscle force generation, thereby extending classical cross-bridge models by involving titin-actin interaction upon active force production. In regions with optimal actin-myosin overlap, the model does not alter energy and force predictions of cross-bridge models for isometric contractions. However, in contrast to cross-bridge models, the three filament model accurately predicts history-dependent force generation in half sarcomeres for eccentric and concentric contractions, and predicts the activation-dependent forces for stretches beyond actin-myosin filament overlap.

Physical Attractiveness and Health in Western Societies: A Review

Science.gov (United States)

Weeden, Jason; Sabini, John

2005-01-01

Evidence from developed Western societies is reviewed for the claims that (a) physical attractiveness judgments are substantially based on body size and shape, symmetry, sex-typical hormonal markers, and other specific cues and (b) physical attractiveness and these cues substantially predict health. Among the cues that the authors review, only…

Three-body Coulomb systems using generalized angular-momentum S states

Science.gov (United States)

Whitten, R. C.; Sims, J. S.

1974-01-01

An expansion of the three-body Coulomb potential in generalized angular-momentum eigenfunctions developed earlier by one of the authors is used to compute energy eigenvalues and eigenfunctions of bound S states of three-body Coulomb systems. The results for He, H(-), e(-)e(+)e(-), and pmu(-)p are compared with the results of other computational approaches.

The influence of leg-to-body ratio (LBR) on judgments of female physical attractiveness: assessments of computer-generated images varying in LBR.

Science.gov (United States)

Frederick, David A; Hadji-Michael, Maria; Furnham, Adrian; Swami, Viren

2010-01-01

The leg-to-body ratio (LBR), which is reliably associated with developmental stability and health outcomes, is an understudied component of human physical attractiveness. Several studies examining the effects of LBR on aesthetic judgments have been limited by the reliance on stimuli composed of hand-drawn silhouettes. In the present study, we developed a new set of female computer-generated images portraying eight levels of LBR that fell within the typical range of human variation. A community sample of 207 Britons in London and students from two samples drawn from a US university (Ns=940, 114) rated the physical attractiveness of the images. We found that mid-ranging female LBRs were perceived as maximally attractive. The present research overcomes some of the problems associated with past work on LBR and aesthetic preferences through use of computer-generated images rather than hand-drawn images and provides an instrument that may be useful in future investigations of LBR preferences. Copyright 2009 Elsevier Ltd. All rights reserved.

Installation with magnetic suspension of test bodies for measurement of small forces. Verification of equivalence of inertial and gravitational mass

International Nuclear Information System (INIS)

Kalebin, S.M.

1988-01-01

Torsion installation with magnetic suspension of test bodies for detection of small forces is considered. Installation application for verification of equivalence of inertial and gravitational mass in the case of test body incidence on the Earth (Etvesh experiment) and in the case of their incidene on the Sun (Dicke experiment) is discussed. The total mass of test bodies, produced in the form of cylinders with 3 cm radius, equals 50 kg (one lead body and one copper body); beam radius of test bodies equals 3 cm (the cylinders are tight against one another); ferrite cylinder with 3 cm radius and 10 cm height is used for their suspension in magnetic field. Effect of thermal noise and electromagnetic force disturbances on measurement results is considered. Conducted calculations show that suggested installation enables to improve the accuracy of verifying mentioned equivalence at least by one order and upwards. This suggests that such installation is a matter of interest for experiments on small force detection

Decoupling Principle Analysis and Development of a Parallel Three-Dimensional Force Sensor.

Science.gov (United States)

Zhao, Yanzhi; Jiao, Leihao; Weng, Dacheng; Zhang, Dan; Zheng, Rencheng

2016-09-15

In the development of the multi-dimensional force sensor, dimension coupling is the ubiquitous factor restricting the improvement of the measurement accuracy. To effectively reduce the influence of dimension coupling on the parallel multi-dimensional force sensor, a novel parallel three-dimensional force sensor is proposed using a mechanical decoupling principle, and the influence of the friction on dimension coupling is effectively reduced by making the friction rolling instead of sliding friction. In this paper, the mathematical model is established by combining with the structure model of the parallel three-dimensional force sensor, and the modeling and analysis of mechanical decoupling are carried out. The coupling degree (ε) of the designed sensor is defined and calculated, and the calculation results show that the mechanical decoupling parallel structure of the sensor possesses good decoupling performance. A prototype of the parallel three-dimensional force sensor was developed, and FEM analysis was carried out. The load calibration and data acquisition experiment system are built, and then calibration experiments were done. According to the calibration experiments, the measurement accuracy is less than 2.86% and the coupling accuracy is less than 3.02%. The experimental results show that the sensor system possesses high measuring accuracy, which provides a basis for the applied research of the parallel multi-dimensional force sensor.

Overweight and obesity prevalence among Cree youth of Eeyou Istchee according to three body mass index classification systems.

Science.gov (United States)

St-Jean, Audray; Meziou, Salma; Ayotte, Pierre; Lucas, Michel

2017-11-22

Little is known about the suitability of three commonly used body mass index (BMI) classification systems for Indigenous youth. We estimated overweight and obesity prevalence among Cree youth of Eeyou Istchee according to three BMI classification systems, assessed the level of agreement between them, and evaluated their accuracy through body fat and cardiometabolic risk factors. Data on 288 youth (aged 8-17 years) were collected. Overweight and obesity prevalence were estimated with Centers for Disease Control and Prevention (CDC), International Obesity Task Force (IOTF) and World Health Organization (WHO) criteria. Agreement was measured with weighted kappa (κw). Associations with body fat and cardiometabolic risk factors were evaluated by analysis of variance. Obesity prevalence was 42.7% with IOTF, 47.2% with CDC, and 49.3% with WHO criteria. Agreement was almost perfect between IOTF and CDC (κw = 0.93), IOTF and WHO (κw = 0.91), and WHO and CDC (κw = 0.94). Means of body fat and cardiometabolic risk factors were significantly higher (P trend  obesity, regardless of the system used. Youth considered overweight by IOTF but obese by CDC or WHO exhibited less severe clinical obesity. IOTF seems to be more accurate in identifying obesity in Cree youth.

Relations Between Lower Body Isometric Muscle Force Characteristics and Start Performance in Elite Male Sprint Swimmers

Directory of Open Access Journals (Sweden)

Igor Beretić

2013-12-01

Full Text Available The aim of the present study was twofold. The first aim was to examine the influence of absolute and relative lower body muscle force on kinematic component which determine the start performance. The second aim was to create multiregressional model which could use as a tool for swimming coaches with the purpose to start performance control and improvement. Twenty seven high-level trained male competitive swimmers all members of the Serbian National Youth and Senior Swimming Team (Age = 21.1 ± 4.3 yrs., Height = 1. 89 ± 0.10 m, Weight = 81.6 ± 8.4 kg, 50m freestyle - long course = 24.36 ± 0.86 s performed two trials of standing leg extensors isometric muscle force testing and three swimming start trials corresponding to 10m distance. The average start time significantly correlated with variables of leg extensors maximum voluntary force (Fmax, r = -0.559, p = 0.002, leg extensors relative muscle voluntary force (Frel, r = -0.727, p < 0.001, leg extensors specific rate of force development (RFD50%, r = -0.338, p = 0.047 and leg extensors relative value of specific rate of force development (RFD50%rel, r = -0.402, p = 0.040. Regression equation for t10m prediction was defined by following variables: maximum voluntary isometric force of leg extensors muscles at absolute and relative level (Fmax and Frel, as well as a specific rate of force development of the same muscle groups (RFD50% and RFD50%rel at absolute and relative level too with 74.4% of explained variance. Contractile abilities indicators of the leg extensors muscles included consideration: Fmax, RFD50%, Frel and RFD50%rel showed significant correlation with swimming start times on 10m. Additionally, the results suggest that swimmers, who possess greater isometric maximum force and specific rate of force development at absolute and relative levels, tend to be able to swim faster on initial 10m swim start perforamnce.

Does being attractive always help? Positive and negative effects of attractiveness on social decision making.

Science.gov (United States)

Agthe, Maria; Spörrle, Matthias; Maner, Jon K

2011-08-01

Previous studies of organizational decision making demonstrate an abundance of positive biases directed toward highly attractive individuals. The current research, in contrast, suggests that when the person being evaluated is of the same sex as the evaluator, attractiveness hurts, rather than helps. Three experiments assessing evaluations of potential job candidates (Studies 1 and 3) and university applicants (Study 2) demonstrated positive biases toward highly attractive other-sex targets but negative biases toward highly attractive same-sex targets. This pattern was mediated by variability in participants' desire to interact with versus avoid the target individual (Studies 1 and 2) and was moderated by participants' level of self-esteem (Study 3); the derogation of attractive same-sex targets was not observed among people with high self-esteem. Findings demonstrate an important exception to the positive effects of attractiveness in organizational settings and suggest that negative responses to attractive same-sex targets stem from perceptions of self-threat.

Verbenone: Dose-Dependent Interruption of Pheromone-Based Attraction of Three Sympatric Species of Pine Bark Beetles (Coleoptera: Scolytidae)

Science.gov (United States)

Daniel R. Miller; John H. Borden; B. Staffan Lindgren

1995-01-01

Verbenone significantly reduced catches of Ips latidens (LeConte), I. pini (Say), and Dendroctonus ponderosae Hopkins in multiple-funnel traps, baited with aggregation pheromones, in stands of lodgepole pine in southern British Columbia. Interruption of attraction was dose dependent for all three species. There...

Physics of few-body λ hypernuclei

International Nuclear Information System (INIS)

Gibson, B.F.

1987-01-01

The energies of the particle-stable states in few-body Λ hypernuclei are summarized. Other topics reviewed include: the role of the hypertriton in determining the spin dependence of the ΛN force, the role of the hypertriton in three-body force investigations, the effect of medium modifications upon ΛN-ΣN coupling in the Λ-4 isodoublet and the spin dependence of the ΛN force, the importance of exact equation formalisms in interpreting precision data, and the need for a renewed effort to identify and measure the masses of ΛΛ hyperfragments. 40 refs., 4 figs., 3 tabs

Three-body interactions and the elastic constants of hcp solid 4He

Science.gov (United States)

Barnes, Ashleigh L.; Hinde, Robert J.

2017-09-01

The effect of three-body interactions on the elastic properties of hexagonal close packed solid 4He is investigated using variational path integral (VPI) Monte Carlo simulations. The solid's nonzero elastic constants are calculated, at T = 0 K and for a range of molar volumes from 7.88 cm3/mol to 20.78 cm3/mol, from the bulk modulus and the three pure shear constants C0, C66, and C44. Three-body interactions are accounted for using our recently reported perturbative treatment based on the nonadditive three-body potential of Cencek et al. Previous studies have attempted to account for the effect of three-body interactions on the elastic properties of solid 4He; however, these calculations have treated zero point motions using either the Einstein or Debye approximations, which are insufficient in the molar volume range where solid 4He is characterized as a quantum solid. Our VPI calculations allow for a more accurate treatment of the zero point motions which include atomic correlation. From these calculations, we find that agreement with the experimental bulk modulus is significantly improved when three-body interactions are considered. In addition, three-body interactions result in non-negligible differences in the calculated pure shear constants and nonzero elastic constants, particularly at higher densities, where differences of up to 26.5% are observed when three-body interactions are included. We compare to the available experimental data and find that our results are generally in as good or better agreement with experiment as previous theoretical investigations.

Comment on ‘Discussion on novel attractive force between ions in quantum plasmas—failure of simulations based on a density functional approach’

International Nuclear Information System (INIS)

Bonitz, M; Pehlke, E; Schoof, T

2013-01-01

In a recent paper (Shukla et al 2013 Phys. Scr. 87 018202) the authors criticized our analysis of the screened proton potential in dense hydrogen that was based on ab initio density functional theory (DFT) simulations (Bonitz et al 2013 Phys. Rev. E 87 037102). In particular, they attributed the absence of the Shukla–Eliasson attractive force between protons in the DFT simulations to a failure of DFT. Here we discuss in detail their arguments and show that their conclusions are incorrect. (comment)

Comment on ‘Discussion on novel attractive force between ions in quantum plasmas—failure of simulations based on a density functional approach’

Science.gov (United States)

Bonitz, M.; Pehlke, E.; Schoof, T.

2013-11-01

In a recent paper (Shukla et al 2013 Phys. Scr. 87 018202) the authors criticized our analysis of the screened proton potential in dense hydrogen that was based on ab initio density functional theory (DFT) simulations (Bonitz et al 2013 Phys. Rev. E 87 037102). In particular, they attributed the absence of the Shukla-Eliasson attractive force between protons in the DFT simulations to a failure of DFT. Here we discuss in detail their arguments and show that their conclusions are incorrect.

Energy Distributions from Three-Body Decaying Many-Body Resonances

International Nuclear Information System (INIS)

Alvarez-Rodriguez, R.; Jensen, A. S.; Fedorov, D. V.; Fynbo, H. O. U.; Garrido, E.

2007-01-01

We compute energy distributions of three particles emerging from decaying many-body resonances. We reproduce the measured energy distributions from decays of two archetypal states chosen as the lowest 0 + and 1 + resonances in 12 C populated in β decays. These states are dominated by sequential, through the 8 Be ground state, and direct decays, respectively. These decay mechanisms are reflected in the ''dynamic'' evolution from small, cluster or shell-model states, to large distances, where the coordinate or momentum space continuum wave functions are accurately computed

Efimov three-body states on top of a Fermi sea

DEFF Research Database (Denmark)

Nygaard, Nicolai Gayle; Zinner, Nikolaj Thomas

2014-01-01

The stabilization of Cooper pairs of bound electrons in the background of a Fermi sea is the origin of superconductivity and the paradigmatic example of the striking influence of many-body physics on few-body properties. In the quantum-mechanical three-body problem the famous Efimov effect yields...

Role of geometrical shape in like-charge attraction of DNA.

Science.gov (United States)

Kuron, Michael; Arnold, Axel

2015-03-01

While the phenomenon of like-charge attraction of DNA is clearly observed experimentally and in simulations, mean-field theories fail to predict it. Kornyshev et al. argued that like-charge attraction is due to DNA's helical geometry and hydration forces. Strong-coupling (SC) theory shows that attraction of like-charged rods is possible through ion correlations alone at large coupling parameters, usually by multivalent counterions. However for SC theory to be applicable, counterion-counterion correlations perpendicular to the DNA strands need to be sufficiently small, which is not a priori the case for DNA even with trivalent counterions. We study a system containing infinitely long DNA strands and trivalent counterions by computer simulations employing varying degrees of coarse-graining. Our results show that there is always attraction between the strands, but its magnitude is indeed highly dependent on the specific shape of the strand. While discreteness of the charge distribution has little influence on the attractive forces, the role of the helical charge distribution is considerable: charged rods maintain a finite distance in equilibrium, while helices collapse to close contact with a phase shift of π, in full agreement with SC predictions. The SC limit is applicable because counterions strongly bind to the charged sites of the helices, so that helix-counterion interactions dominate over counterion-counterion interactions. Thus DNA's helical geometry is not crucial for like-charge DNA attraction, but strongly enhances it, and electrostatic interactions in the strong-coupling limit are sufficient to explain this attraction.

Crossing Over from Attractive to Repulsive Interactions in a Tunneling Bosonic Josephson Junction.

Science.gov (United States)

Spagnolli, G; Semeghini, G; Masi, L; Ferioli, G; Trenkwalder, A; Coop, S; Landini, M; Pezzè, L; Modugno, G; Inguscio, M; Smerzi, A; Fattori, M

2017-06-09

We explore the interplay between tunneling and interatomic interactions in the dynamics of a bosonic Josephson junction. We tune the scattering length of an atomic ^{39}K Bose-Einstein condensate confined in a double-well trap to investigate regimes inaccessible to other superconducting or superfluid systems. In the limit of small-amplitude oscillations, we study the transition from Rabi to plasma oscillations by crossing over from attractive to repulsive interatomic interactions. We observe a critical slowing down in the oscillation frequency by increasing the strength of an attractive interaction up to the point of a quantum phase transition. With sufficiently large initial oscillation amplitude and repulsive interactions, the system enters the macroscopic quantum self-trapping regime, where we observe coherent undamped oscillations with a self-sustained average imbalance of the relative well population. The exquisite agreement between theory and experiments enables the observation of a broad range of many body coherent dynamical regimes driven by tunable tunneling energy, interactions and external forces, with applications spanning from atomtronics to quantum metrology.

Direct measurement of sub-Debye-length attraction between oppositely charged surfaces.

Science.gov (United States)

Kampf, Nir; Ben-Yaakov, Dan; Andelman, David; Safran, S A; Klein, Jacob

2009-09-11

Using a surface force balance with fast video analysis, we have measured directly the attractive forces between oppositely charged solid surfaces (charge densities sigma(+), sigma(-)) across water over the entire range of interaction, in particular, at surface separations D below the Debye screening length lambda(S). At very low salt concentration we find a long-ranged attraction between the surfaces (onset ca. 100 nm), whose variation at D

A review of a method for dynamic load distribution, dynamical modeling, and explicit internal force control when two manipulators mutually lift and transport a rigid body object

International Nuclear Information System (INIS)

Unseren, M.A.

1997-01-01

The paper reviews a method for modeling and controlling two serial link manipulators which mutually lift and transport a rigid body object in a three dimensional workspace. A new vector variable is introduced which parameterizes the internal contact force controlled degrees of freedom. A technique for dynamically distributing the payload between the manipulators is suggested which yields a family of solutions for the contact forces and torques the manipulators impart to the object. A set of rigid body kinematic constraints which restrict the values of the joint velocities of both manipulators is derived. A rigid body dynamical model for the closed chain system is first developed in the joint space. The model is obtained by generalizing the previous methods for deriving the model. The joint velocity and acceleration variables in the model are expressed in terms of independent pseudovariables. The pseudospace model is transformed to obtain reduced order equations of motion and a separate set of equations governing the internal components of the contact forces and torques. A theoretic control architecture is suggested which explicitly decouples the two sets of equations comprising the model. The controller enables the designer to develop independent, non-interacting control laws for the position control and internal force control of the system

A review of a method for dynamic load distribution, dynamical modeling, and explicit internal force control when two manipulators mutually lift and transport a rigid body object

Energy Technology Data Exchange (ETDEWEB)

Unseren, M.A.

1997-04-20

The paper reviews a method for modeling and controlling two serial link manipulators which mutually lift and transport a rigid body object in a three dimensional workspace. A new vector variable is introduced which parameterizes the internal contact force controlled degrees of freedom. A technique for dynamically distributing the payload between the manipulators is suggested which yields a family of solutions for the contact forces and torques the manipulators impart to the object. A set of rigid body kinematic constraints which restrict the values of the joint velocities of both manipulators is derived. A rigid body dynamical model for the closed chain system is first developed in the joint space. The model is obtained by generalizing the previous methods for deriving the model. The joint velocity and acceleration variables in the model are expressed in terms of independent pseudovariables. The pseudospace model is transformed to obtain reduced order equations of motion and a separate set of equations governing the internal components of the contact forces and torques. A theoretic control architecture is suggested which explicitly decouples the two sets of equations comprising the model. The controller enables the designer to develop independent, non-interacting control laws for the position control and internal force control of the system.

Sweet attraction: sugarcane pollen-associated volatiles attract gravid Anopheles arabiensis.

Science.gov (United States)

Wondwosen, Betelehem; Birgersson, Göran; Tekie, Habte; Torto, Baldwyn; Ignell, Rickard; Hill, Sharon R

2018-02-21

Anopheles arabiensis is a key vector for the transmission of human malaria in sub-Saharan Africa. Over the past 10,000 years, humans have successfully cultivated grasses and altered the landscape, creating An. arabiensis favourable environments that contain excellent habitats for both larvae and adults. Sugarcane is the most expanding agricultural system in sub-Saharan Africa, and is linked to the increased threat of malaria in rural communities. The prolific production and wind dispersal of sugarcane pollen, together with standing pools of water, often provide, as a result of irrigation, a nutrient-rich environment for the offspring of gravid malaria mosquitoes. In the present study, sugarcane pollen-associated volatiles from two cultivars are shown to attract gravid An. arabiensis in a still air two-port olfactometer and stimulate egg laying in an oviposition bioassay. Through combined gas chromatography and electroantennographic detection, as well as combined gas chromatography and mass spectrometric analyses, we identified the bioactive volatiles and generated a synthetic blend that reproduced the full behavioural repertoire of gravid mosquitoes in the Y-tube assay. Two subtractive odour blends, when compared with the full blend, were significantly more attractive. These three and four-component subtractive blends share the compounds (1R)-(+)-α-pinene, nonanal and benzaldehyde, of which, (1R)-(+)-α-pinene and nonanal are found in the attractive odour blends from rice plants and maize pollen. In pairwise comparisons, the rice synthetic odour blend was more attractive to gravid mosquitoes than either of the pollen blends, whereas the pollen blends did not differ in attraction. The attraction of gravid females to sugarcane pollen volatiles demonstrated in this study, together with the previously found grass-associated volatiles, raise the potential of developing a bioactive chimeric blend to attract gravid malaria mosquitoes. This is discussed in relation to

Electronic circuit for control rod attracting electromagnet

International Nuclear Information System (INIS)

Ito, Koji.

1991-01-01

The present invention provides a discharging circuit for control rod attracting electromagnet used for a reactor which is highly reliable and has high performance. The resistor of the circuit comprises a non-linear resistor element and a blocking rectification element connected in series. The discharging circuit can be prevented from short-circuit by selecting a resistor having a resistance value about ten times as great as the coil resistance, even in a case where the blocking rectification element and the non-linear resistor element are failed. Accordingly, reduction of attracting force and the increase of scream releasing time can be minimized. (I.S.)

Loop corrections and other many-body effects in relativistic field theories

International Nuclear Information System (INIS)

Ainsworth, T.L.; Brown, G.E.; Prakash, M.; Weise, W.

1988-01-01

Incorporation of effective masses into negative energy states (nucleon loop corrections) gives rise to repulsive many-body forces, as has been known for some time. Rather than renormalizing away the three- and four-body terms, we introduce medium corrections into the effective σ-exchange, which roughly cancel the nucleon loop terms for densities ρ ≅ ρ nm , where ρ nm is nuclear matter density. Going to higher densities, the repulsive contributions tend to saturate whereas the attractive ones keep on growing in magnitude. The latter is achieved through use of a density-dependent effective mass for the σ-particle, m σ = m σ (ρ), such that m σ (ρ) decreases with increasing density. Such a behavior is seen e.g. in the Nambu-Jona-Lasinio model. It is argued that a smooth transition to chiral restoration implies a similar behavior. The resulting nuclear equation of state is, because of the self-consistency in the problem, immensely insensitive to changes in the mass or coupling constant of the σ-particle. (orig.)

Facial Diversity and Infant Preferences for Attractive Faces.

Science.gov (United States)

Langlois, Judith H.; And Others

1991-01-01

Three studies examined infant preferences for attractive faces of White males, White females, Black females, and infants. Infants viewed pairs of faces rated for attractiveness by adults. Preferences for attractive faces were found for all facial types. (BC)

Whole-Body Human Inverse Dynamics with Distributed Micro-Accelerometers, Gyros and Force Sensing

Directory of Open Access Journals (Sweden)

Claudia Latella

2016-05-01

Full Text Available Human motion tracking is a powerful tool used in a large range of applications that require human movement analysis. Although it is a well-established technique, its main limitation is the lack of estimation of real-time kinetics information such as forces and torques during the motion capture. In this paper, we present a novel approach for a human soft wearable force tracking for the simultaneous estimation of whole-body forces along with the motion. The early stage of our framework encompasses traditional passive marker based methods, inertial and contact force sensor modalities and harnesses a probabilistic computational technique for estimating dynamic quantities, originally proposed in the domain of humanoid robot control. We present experimental analysis on subjects performing a two degrees-of-freedom bowing task, and we estimate the motion and kinetics quantities. The results demonstrate the validity of the proposed method. We discuss the possible use of this technique in the design of a novel soft wearable force tracking device and its potential applications.

Effects of three-body interactions on the dynamics of entanglement in spin chains

International Nuclear Information System (INIS)

Shi Cuihua; Wu Yinzhong; Li Zhenya

2009-01-01

With the consideration of three-body interaction, dynamics of pairwise entanglement in spin chains is studied. The dependence of pairwise entanglement dynamics on the type of coupling, and distance between the spins is analyzed in a finite chain for different initial states. It is found that, for an Ising chain, three-body interactions are not in favor of preparing entanglement between the nearest neighbor spins, while three-body interactions are favorable for creating entanglement between remote spins from a separable initial state. For an isotropic Heisenberg chain, the pairwise concurrence will decrease when three-body interactions are considered both for a separable initial state and for a maximally entangled initial state, however, three-body interactions will retard the decay of the concurrence in an Ising chain when the initial state takes the maximally entangled state.

Comparison of Ground Reaction Forces, Center of Pressure and Body Center of Mass Changes in the Voluntary, Semi-Voluntary and Involuntary Gait Termination in Healthy Young Men

Directory of Open Access Journals (Sweden)

behrooz teymourian

2016-03-01

Full Text Available Objective: The aim of this study was comparing the ground reaction forces, center of pressure and body center of mass changes in voluntary, semi-voluntary and involuntary gait termination in healthy young men. Methods: In this study, 12 young men performed termination of gait in three different patterns. The variable of peak antero-posterior and vertical forces in two directions at both limbs, the time to reach peak and average forces in every limb in both directions, the center of pressure displacement of medio-lateral and antero-posterior direction for each limb and the net center of pressure and the displacement of the center of mass motion in all three motion plates were recorded using motion analysis system and force plate.The repeated measurements test was used to compare three patterns of gait termination at significance level of p&le0.5. Results: The results showed a significant difference in variables of peak antero-posterior force, the time to reach peak antero-posterior force and mean antero-posterior forces of the leading limb, the peak antero-posterior force of the trialing limbs, the depth force of leading limbs, medio-lateral cop of leading limbs displacement and vertical displacement of the center of mass, among different patterns of gait termination. Conclusion: While walking, the probability of a fall or collision damage, when a sudden or unexpected stop is required, increases. Therefore, more coordination between neuromuscular systems is required.

Three-axial force sensor with capacitive read-out using a differential relaxation oscillator

NARCIS (Netherlands)

Brookhuis, Robert Anton; Wiegerink, Remco J.; Lammerink, Theodorus S.J.; Krijnen, Gijsbertus J.M.

2013-01-01

A silicon three-axis force sensor is designed and realized to be used for measurement of the interaction force between a human finger and the environment. To detect the force components, a capacitive read-out system using a novel relaxation oscillator has been developed with an output frequency

Cultured skin microbiota attracts malaria mosquitoes

NARCIS (Netherlands)

Verhulst, Niels O.; Beijleveld, Hans; Knols, Bart Gj; Takken, Willem; Schraa, Gosse; Bouwmeester, Harro J.; Smallegange, Renate C.

2009-01-01

Host-seeking of the African malaria mosquito, Anopheles gambiae sensu stricto, is guided by human odours. The precise nature of the odours, and the composition of attractive blends of volatiles, remains largely unknown. Skin microbiota plays an important role in the production of human body odours.

Tests of the discretized-continuum method in three-body dipole strengths

Energy Technology Data Exchange (ETDEWEB)

Pinilla, E.C., E-mail: epinilla@ulb.ac.be [Physique Nucleaire Theorique et Physique Mathematique, C.P. 229, Universite Libre de Bruxelles (ULB), B 1050 Brussels (Belgium); Baye, D., E-mail: dbaye@ulb.ac.be [Physique Quantique, C.P. 165/82, Universite Libre de Bruxelles (ULB), B 1050 Brussels (Belgium); Physique Nucleaire Theorique et Physique Mathematique, C.P. 229, Universite Libre de Bruxelles (ULB), B 1050 Brussels (Belgium); Descouvemont, P., E-mail: pdesc@ulb.ac.be [Physique Nucleaire Theorique et Physique Mathematique, C.P. 229, Universite Libre de Bruxelles (ULB), B 1050 Brussels (Belgium); Horiuchi, W., E-mail: whoriuchi@riken.jp [RIKEN Nishina Center, Wako 351-0918 (Japan); Suzuki, Y., E-mail: suzuki@nt.sc.niigata-u.ac.jp [Department of Physics, Niigata University, Niigata 950-2181 (Japan); RIKEN Nishina Center, Wako 351-0918 (Japan)

2011-08-15

We investigate the {sup 6}He dipole distribution in a three-body {alpha}+n+n model. Two approaches are used to describe the three-body 1{sup -} continuum: the discretized-continuum method, where the scattering wave functions are approximated by square-integrable functions, and the R-matrix formalism, where their asymptotic behaviour is taken into account. We show that some ambiguity exists in the pseudostate method, owing to the smoothing technique, necessary to derive continuous distributions. We show evidence for the important role of the halo structure in the E1 dipole strength. We also address the treatment of Pauli forbidden states in the three-body wave functions.

Three-dimensional HepaRG model as an attractive tool for toxicity testing.

Science.gov (United States)

Leite, Sofia B; Wilk-Zasadna, Iwona; Zaldivar, Jose M; Airola, Elodie; Reis-Fernandes, Marcos A; Mennecozzi, Milena; Guguen-Guillouzo, Christiane; Chesne, Christopher; Guillou, Claude; Alves, Paula M; Coecke, Sandra

2012-11-01

The culture of HepaRG cells as three dimensional (3D) structures in the spinner-bioreactor may represent added value as a hepatic system for toxicological purposes. The use of a cost-effective commercially available bioreactor, which is compatible with high-throughput cell analysis, constitutes an attractive approach for routine use in the drug testing industry. In order to assess specific aspects of the biotransformation capacity of the bioreactor-based HepaRG system, the induction of CYP450 enzymes (i.e., CYP1A2, 2B6, 2C9, and 3A4) and the activity of the phase II enzyme, uridine diphosphate glucuronoltransferase (UGT), were tested. The long-term functionality of the system was demonstrated by 7-week stable profiles of albumin secretion, CYP3A4 induction, and UGT activities. Immunofluorescence-based staining showed formation of tissue-like arrangements including bile canaliculi-like structures and polar distribution of transporters. The use of in silico models to analyze the in vitro data related to hepatotoxic activity of acetaminophen (APAP) demonstrated the advantage of the integration of kinetic and dynamic aspects for a better understanding of the in vitro cell behavior. The bioactivation of APAP and its related cytotoxicity was assessed in a system compatible to high-throughput screening. The approach also proved to be a good strategy to reduce the time necessary to obtain fully differentiated cell cultures. In conclusion, HepaRG cells cultured in 3D spinner-bioreactors are an attractive tool for toxicological studies, showing a liver-like performance and demonstrating a practical applicability for toxicodynamic approaches.

Predicting human chronically paralyzed muscle force: a comparison of three mathematical models.

Science.gov (United States)

Frey Law, Laura A; Shields, Richard K

2006-03-01

Chronic spinal cord injury (SCI) induces detrimental musculoskeletal adaptations that adversely affect health status, ranging from muscle paralysis and skin ulcerations to osteoporosis. SCI rehabilitative efforts may increasingly focus on preserving the integrity of paralyzed extremities to maximize health quality using electrical stimulation for isometric training and/or functional activities. Subject-specific mathematical muscle models could prove valuable for predicting the forces necessary to achieve therapeutic loading conditions in individuals with paralyzed limbs. Although numerous muscle models are available, three modeling approaches were chosen that can accommodate a variety of stimulation input patterns. To our knowledge, no direct comparisons between models using paralyzed muscle have been reported. The three models include 1) a simple second-order linear model with three parameters and 2) two six-parameter nonlinear models (a second-order nonlinear model and a Hill-derived nonlinear model). Soleus muscle forces from four individuals with complete, chronic SCI were used to optimize each model's parameters (using an increasing and decreasing frequency ramp) and to assess the models' predictive accuracies for constant and variable (doublet) stimulation trains at 5, 10, and 20 Hz in each individual. Despite the large differences in modeling approaches, the mean predicted force errors differed only moderately (8-15% error; P=0.0042), suggesting physiological force can be adequately represented by multiple mathematical constructs. The two nonlinear models predicted specific force characteristics better than the linear model in nearly all stimulation conditions, with minimal differences between the two nonlinear models. Either nonlinear mathematical model can provide reasonable force estimates; individual application needs may dictate the preferred modeling strategy.

Three-bead steering microswimmers

Science.gov (United States)

Rizvi, Mohd Suhail; Farutin, Alexander; Misbah, Chaouqi

2018-02-01

The self-propelled microswimmers have recently attracted considerable attention as model systems for biological cell migration as well as artificial micromachines. A simple and well-studied microswimmer model consists of three identical spherical beads joined by two springs in a linear fashion with active oscillatory forces being applied on the beads to generate self-propulsion. We have extended this linear microswimmer configuration to a triangular geometry where the three beads are connected by three identical springs in an equilateral triangular manner. The active forces acting on each spring can lead to autonomous steering motion; i.e., allowing the swimmer to move along arbitrary paths. We explore the microswimmer dynamics analytically and pinpoint its rich character depending on the nature of the active forces. The microswimmers can translate along a straight trajectory, rotate at a fixed location, as well as perform a simultaneous translation and rotation resulting in complex curved trajectories. The sinusoidal active forces on the three springs of the microswimmer contain naturally four operating parameters which are more than required for the steering motion. We identify the minimal operating parameters which are essential for the motion of the microswimmer along any given arbitrary trajectory. Therefore, along with providing insights into the mechanics of the complex motion of the natural and artificial microswimmers, the triangular three-bead microswimmer can be utilized as a model for targeted drug delivery systems and autonomous underwater vehicles where intricate trajectories are involved.

Stability and decay rates of nonisotropic attractive Bose-Einstein condensates

International Nuclear Information System (INIS)

Huepe, C.; Tuckerman, L. S.; Metens, S.; Brachet, M. E.

2003-01-01

Nonisotropic attractive Bose-Einstein condensates are investigated numerically with Newton and inverse Arnoldi methods. The stationary solutions of the Gross-Pitaevskii equation and their linear stability are computed. Bifurcation diagrams are calculated and used to find the condensate decay rates corresponding to macroscopic quantum tunneling, two-three-body inelastic collisions, and thermally induced collapse. Isotropic and nonisotropic condensates are compared. The effect of anisotropy on the bifurcation diagram and the decay rates is discussed. Spontaneous isotropization of the condensates is found to occur. The influence of isotropization on the decay rates is characterized near the critical point

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. © 2011 The Authors. Scandinavian Journal of Psychology © 2011 The Scandinavian Psychological Associations.

Body Weight and Matching with a Physically Attractive Romantic Partner

Science.gov (United States)

Carmalt, Julie H.; Cawley, John; Joyner, Kara; Sobal, Jeffery

2008-01-01

Matching and attribute trade are two perspectives used to explain mate selection. We investigated patterns of matching and trade, focusing on obesity, using Add Health Romantic Pair data (N = 1,405 couples). Obese individuals, relative to healthy weight individuals, were less likely to have physically attractive partners, with this disadvantage…

Imaging three-dimensional surface objects with submolecular resolution by atomic force microscopy

Czech Academy of Sciences Publication Activity Database

Moreno, C.; Stetsovych, Oleksandr; Shimizu, T.K.; Custance, O.

2015-01-01

Roč. 15, č. 4 (2015), s. 2257-2262 ISSN 1530-6984 Institutional support: RVO:68378271 Keywords : noncontact atomic force microscopy (NC- AFM ) * submolecular resolution * three-dimensional dynamic force spectroscopy * high-resolution imaging Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 13.779, year: 2015

Human Factors Lessons Learned from Flight Testing Wingless Lifting Body Vehicles

Science.gov (United States)

Merlin, Peter William

2014-01-01

Since the 1960s, NASA, the Air Force, and now private industry have attempted to develop an operational human crewed reusable spacecraft with a wingless, lifting body configuration. This type of vehicle offers increased mission flexibility and greater reentry cross range than capsule type craft, and is particularly attractive due to the capability to land on a runway. That capability, however, adds complexity to the human factors engineering requirements of developing such aircraft.

Conformation-dependent DNA attraction

Science.gov (United States)

Li, Weifeng; Nordenskiöld, Lars; Zhou, Ruhong; Mu, Yuguang

2014-05-01

Understanding how DNA molecules interact with other biomolecules is related to how they utilize their functions and is therefore critical for understanding their structure-function relationships. For a long time, the existence of Z-form DNA (a left-handed double helical version of DNA, instead of the common right-handed B-form) has puzzled the scientists, and the definitive biological significance of Z-DNA has not yet been clarified. In this study, the effects of DNA conformation in DNA-DNA interactions are explored by molecular dynamics simulations. Using umbrella sampling, we find that for both B- and Z-form DNA, surrounding Mg2+ ions always exert themselves to screen the Coulomb repulsion between DNA phosphates, resulting in very weak attractive force. On the contrary, a tight and stable bound state is discovered for Z-DNA in the presence of Mg2+ or Na+, benefiting from their hydrophobic nature. Based on the contact surface and a dewetting process analysis, a two-stage binding process of Z-DNA is outlined: two Z-DNA first attract each other through charge screening and Mg2+ bridges to phosphate groups in the same way as that of B-DNA, after which hydrophobic contacts of the deoxyribose groups are formed via a dewetting effect, resulting in stable attraction between two Z-DNA molecules. The highlighted hydrophobic nature of Z-DNA interaction from the current study may help to understand the biological functions of Z-DNA in gene transcription.Understanding how DNA molecules interact with other biomolecules is related to how they utilize their functions and is therefore critical for understanding their structure-function relationships. For a long time, the existence of Z-form DNA (a left-handed double helical version of DNA, instead of the common right-handed B-form) has puzzled the scientists, and the definitive biological significance of Z-DNA has not yet been clarified. In this study, the effects of DNA conformation in DNA-DNA interactions are explored by

Three-Dimensional Force Measurements During Rapid Palatal Expansion in Sus scrofa

Directory of Open Access Journals (Sweden)

Kelly Goeckner

2016-04-01

Full Text Available Rapid palatal expansion is an orthodontic procedure widely used to correct the maxillary arch. However, its outcome is significantly influenced by factors that show a high degree of variability amongst patients. The traditional treatment methodology is based on an intuitive and heuristic treatment approach because the forces applied in the three dimensions are indeterminate. To enable optimal and individualized treatment, it is essential to measure the three-dimensional (3D forces and displacements created by the expander. This paper proposes a method for performing these 3D measurements using a single embedded strain sensor, combining experimental measurements of strain in the palatal expander with 3D finite element analysis (FEA. The method is demonstrated using the maxillary jaw from a freshly euthanized pig (Sus scrofa and a hyrax-design rapid palatal expander (RPE appliance with integrated strain gage. The strain gage measurements are recorded using a computer interface, following which the expansion forces and extent of expansion are estimated by FEA. A total activation of 2.0 mm results in peak total force of about 100 N—almost entirely along the direction of expansion. The results also indicate that more than 85% of the input activation is immediately transferred to the palate and/or teeth. These studies demonstrate a method for assessing and individualizing expansion magnitudes and forces during orthopedic expansion of the maxilla. This provides the basis for further development of smart orthodontic appliances that provide real-time readouts of forces and movements, which will allow personalized, optimal treatment.

Manipulating bubbles with secondary Bjerknes forces

Energy Technology Data Exchange (ETDEWEB)

Lanoy, Maxime [Institut Langevin, ESPCI ParisTech, CNRS (UMR 7587), PSL Research University, 1 rue Jussieu, 75005 Paris (France); Laboratoire Matière et Systèmes Complexes, Université Paris-Diderot, CNRS (UMR 7057), 10 rue Alice Domon et Léonie Duquet, 75013 Paris (France); Derec, Caroline; Leroy, Valentin [Laboratoire Matière et Systèmes Complexes, Université Paris-Diderot, CNRS (UMR 7057), 10 rue Alice Domon et Léonie Duquet, 75013 Paris (France); Tourin, Arnaud [Institut Langevin, ESPCI ParisTech, CNRS (UMR 7587), PSL Research University, 1 rue Jussieu, 75005 Paris (France)

2015-11-23

Gas bubbles in a sound field are submitted to a radiative force, known as the secondary Bjerknes force. We propose an original experimental setup that allows us to investigate in detail this force between two bubbles, as a function of the sonication frequency, as well as the bubbles radii and distance. We report the observation of both attractive and, more interestingly, repulsive Bjerknes force, when the two bubbles are driven in antiphase. Our experiments show the importance of taking multiple scatterings into account, which leads to a strong acoustic coupling of the bubbles when their radii are similar. Our setup demonstrates the accuracy of secondary Bjerknes forces for attracting or repealing a bubble, and could lead to new acoustic tools for noncontact manipulation in microfluidic devices.

Manipulating bubbles with secondary Bjerknes forces

International Nuclear Information System (INIS)

Lanoy, Maxime; Derec, Caroline; Leroy, Valentin; Tourin, Arnaud

2015-01-01

Gas bubbles in a sound field are submitted to a radiative force, known as the secondary Bjerknes force. We propose an original experimental setup that allows us to investigate in detail this force between two bubbles, as a function of the sonication frequency, as well as the bubbles radii and distance. We report the observation of both attractive and, more interestingly, repulsive Bjerknes force, when the two bubbles are driven in antiphase. Our experiments show the importance of taking multiple scatterings into account, which leads to a strong acoustic coupling of the bubbles when their radii are similar. Our setup demonstrates the accuracy of secondary Bjerknes forces for attracting or repealing a bubble, and could lead to new acoustic tools for noncontact manipulation in microfluidic devices

Comparison of Cellulose Iβ Simulations with Three Carbohydrate Force Fields.

Science.gov (United States)

Matthews, James F; Beckham, Gregg T; Bergenstråhle-Wohlert, Malin; Brady, John W; Himmel, Michael E; Crowley, Michael F

2012-02-14

Molecular dynamics simulations of cellulose have recently become more prevalent due to increased interest in renewable energy applications, and many atomistic and coarse-grained force fields exist that can be applied to cellulose. However, to date no systematic comparison between carbohydrate force fields has been conducted for this important system. To that end, we present a molecular dynamics simulation study of hydrated, 36-chain cellulose Iβ microfibrils at room temperature with three carbohydrate force fields (CHARMM35, GLYCAM06, and Gromos 45a4) up to the near-microsecond time scale. Our results indicate that each of these simulated microfibrils diverge from the cellulose Iβ crystal structure to varying degrees under the conditions tested. The CHARMM35 and GLYCAM06 force fields eventually result in structures similar to those observed at 500 K with the same force fields, which are consistent with the experimentally observed high-temperature behavior of cellulose I. The third force field, Gromos 45a4, produces behavior significantly different from experiment, from the other two force fields, and from previously reported simulations with this force field using shorter simulation times and constrained periodic boundary conditions. For the GLYCAM06 force field, initial hydrogen-bond conformations and choice of electrostatic scaling factors significantly affect the rate of structural divergence. Our results suggest dramatically different time scales for convergence of properties of interest, which is important in the design of computational studies and comparisons to experimental data. This study highlights that further experimental and theoretical work is required to understand the structure of small diameter cellulose microfibrils typical of plant cellulose.

Very massive runaway stars from three-body encounters

Science.gov (United States)

Gvaramadze, Vasilii V.; Gualandris, Alessia

2011-01-01

Very massive stars preferentially reside in the cores of their parent clusters and form binary or multiple systems. We study the role of tight very massive binaries in the origin of the field population of very massive stars. We performed numerical simulations of dynamical encounters between single (massive) stars and a very massive binary with parameters similar to those of the most massive known Galactic binaries, WR 20a and NGC 3603-A1. We found that these three-body encounters could be responsible for the origin of high peculiar velocities (≥70 km s-1) observed for some very massive (≥60-70 M⊙) runaway stars in the Milky Way and the Large Magellanic Cloud (e.g. λ Cep, BD+43°3654, Sk -67°22, BI 237, 30 Dor 016), which can hardly be explained within the framework of the binary-supernova scenario. The production of high-velocity massive stars via three-body encounters is accompanied by the recoil of the binary in the opposite direction to the ejected star. We show that the relative position of the very massive binary R145 and the runaway early B-type star Sk-69°206 on the sky is consistent with the possibility that both objects were ejected from the central cluster, R136, of the star-forming region 30 Doradus via the same dynamical event - a three-body encounter.

The contribution of the electrostatic proximity force to atomic force microscopy with insulators

International Nuclear Information System (INIS)

Stanley Czarnecki, W.; Schein, L.B.

2005-01-01

Measurements, using atomic force microscopy, of the force and force derivative on a charged insulating micron sized sphere as a function of gap between the sphere and a conductive plane have revealed attractive forces at finite gaps that are larger than predicted by either van der Waals or conventional electrostatic forces. We suggest that these observations may be due to an electrostatic force that we have identified theoretically and call the proximity force. This proximity force is due to the discrete charges on the surface of the sphere in close proximity to the plane

The contribution of the electrostatic proximity force to atomic force microscopy with insulators

Energy Technology Data Exchange (ETDEWEB)

Stanley Czarnecki, W. [Aetas Technology Corporation, P.O. Box 53398, Irvine, CA 92619-3398 (United States); IBM Corporation, 5600 Cottle Rd., Building 13, San Jose, CA 95193 (United States); Schein, L.B. [Aetas Technology Corporation, P.O. Box 53398, Irvine, CA 92619-3398 (United States)]. E-mail: schein@prodigy.net

2005-05-16

Measurements, using atomic force microscopy, of the force and force derivative on a charged insulating micron sized sphere as a function of gap between the sphere and a conductive plane have revealed attractive forces at finite gaps that are larger than predicted by either van der Waals or conventional electrostatic forces. We suggest that these observations may be due to an electrostatic force that we have identified theoretically and call the proximity force. This proximity force is due to the discrete charges on the surface of the sphere in close proximity to the plane.

Facial attractiveness, symmetry, and physical fitness in young women.

Science.gov (United States)

Hönekopp, Johannes; Bartholomé, Tobias; Jansen, Gregor

2004-06-01

This study explores the evolutionary-based hypothesis that facial attractiveness (a guiding force in mate selection) is a cue for physical fitness (presumably an important contributor to mate value in ancestral times). Since fluctuating asymmetry, a measure of developmental stability, is known to be a valid cue for fitness in several biological domains, we scrutinized facial asymmetry as a potential mediator between attractiveness and fitness. In our sample of young women, facial beauty indeed indicated physical fitness. The relationships that pertained to asymmetry were in the expected direction. However, a closer analysis revealed that facial asymmetry did not mediate the relationship between fitness and attractiveness. Unexpected problems regarding the measurement of facial asymmetry are discussed.

The influence of feminist ascription on judgements of women's physical attractiveness.

Science.gov (United States)

Swami, Viren; Salem, Natalie; Furnham, Adrian; Tovée, Martin J

2008-06-01

The present study examined the effect of feminist ascription on perceptions of the physical attractiveness of women ranging in body mass index (BMI). One-hundred and twenty-nine women who self-identified as feminists and 132 who self-identified as non-feminists rated a series of 10 images of women that varied in BMI from emaciated to obese. Results showed no significant differences between feminist and non-feminists in the figure they considered to be maximally attractive. However, feminists were more likely to positively perceive a wider range of body sizes than non-feminists. These results are discussed in relation to possible protective factors against the internalisation of the thin ideal and body objectification.

A comprehensive treatment of electromagnetic interactions and the three-body spectator equations

Energy Technology Data Exchange (ETDEWEB)

Jiri Adam; Jay Van Orden

2004-10-01

We present a general derivation the three-body spectator (Gross) equations and the corresponding electromagnetic currents. As in previous paper on two-body systems, the wave equations and currents are derived from those for Bethe-Salpeter equation with the help of algebraic method using a concise matrix notation. The three-body interactions and currents introduced by the transition to the spectator approach are isolated and the matrix elements of the e.m. current are presented in detail for system of three indistinguishable particles, namely for elastic scattering and for two and three body break-up. The general expressions are reduced to the one-boson-exchange approximation to make contact with previous work. The method is general in that it does not rely on introduction of the electromagnetic interaction with the help of the minimal replacement. It would therefore work also for other external fields.

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…

Dispersion Forces

CERN Document Server

Buhmann, Stefan Yoshi

2012-01-01

In this book, a modern unified theory of dispersion forces on atoms and bodies is presented which covers a broad range of advanced aspects and scenarios. Macroscopic quantum electrodynamics is shown to provide a powerful framework for dispersion forces which allows for discussing general properties like their non-additivity and the relation between microscopic and macroscopic interactions. It is demonstrated how the general results can be used to obtain dispersion forces on atoms in the presence of bodies of various shapes and materials. Starting with a brief recapitulation of volume I, this volume II deals especially with bodies of irregular shapes, universal scaling laws, dynamical forces on excited atoms, enhanced forces in cavity quantum electrodynamics, non-equilibrium forces in thermal environments and quantum friction. The book gives both the specialist and those new to the field a thorough overview over recent results in the field. It provides a toolbox for studying dispersion forces in various contex...

Radial Motion of Two Mutually Attracting Particles

Science.gov (United States)

Mungan, Carl E.

2009-01-01

A pair of masses or opposite-sign charges released from rest will move directly toward each other under the action of the inverse-distance-squared force of attraction between them. An exact expression for the separation distance as a function of time can only be found by numerically inverting the solution of a differential equation. A simpler,…

A review of a method for dynamic load distribution, dynamic modeling, and explicit internal force control when two serial link manipulators mutually lift and transport a rigid body object

International Nuclear Information System (INIS)

Unseren, M.A.

1997-09-01

The report reviews a method for modeling and controlling two serial link manipulators which mutually lift and transport a rigid body object in a three dimensional workspace. A new vector variable is introduced which parameterizes the internal contact force controlled degrees of freedom. A technique for dynamically distributing the payload between the manipulators is suggested which yields a family of solutions for the contact forces and torques the manipulators impart to the object. A set of rigid body kinematic constraints which restricts the values of the joint velocities of both manipulators is derived. A rigid body dynamical model for the closed chain system is first developed in the joint space. The model is obtained by generalizing the previous methods for deriving the model. The joint velocity and acceleration variables in the model are expressed in terms of independent pseudovariables. The pseudospace model is transformed to obtain reduced order equations of motion and a separate set of equations governing the internal components of the contact forces and torques. A theoretic control architecture is suggested which explicitly decouples the two sets of equations comprising the model. The controller enables the designer to develop independent, non-interacting control laws for the position control and internal force control of the system

A review of a method for dynamic load distribution, dynamic modeling, and explicit internal force control when two serial link manipulators mutually lift and transport a rigid body object

Energy Technology Data Exchange (ETDEWEB)

Unseren, M.A.

1997-09-01

The report reviews a method for modeling and controlling two serial link manipulators which mutually lift and transport a rigid body object in a three dimensional workspace. A new vector variable is introduced which parameterizes the internal contact force controlled degrees of freedom. A technique for dynamically distributing the payload between the manipulators is suggested which yields a family of solutions for the contact forces and torques the manipulators impart to the object. A set of rigid body kinematic constraints which restricts the values of the joint velocities of both manipulators is derived. A rigid body dynamical model for the closed chain system is first developed in the joint space. The model is obtained by generalizing the previous methods for deriving the model. The joint velocity and acceleration variables in the model are expressed in terms of independent pseudovariables. The pseudospace model is transformed to obtain reduced order equations of motion and a separate set of equations governing the internal components of the contact forces and torques. A theoretic control architecture is suggested which explicitly decouples the two sets of equations comprising the model. The controller enables the designer to develop independent, non-interacting control laws for the position control and internal force control of the system.

The Athletic Body.

Science.gov (United States)

Edgar, Andrew

2016-09-10

This paper seeks to explore the attraction and the beauty of the contemporary athletic body. It will be suggested that a body shaped through muscular bulk and definition has come to be seen as aesthetically normative. This body differs from the body of athletes from the early and mid-twentieth century. It will be argued that the contemporary body is not merely the result of advances in sports science, but rather that it is expressive of certain meanings and values. The visual similarity of the contemporary athletic body and that of the comic book superhero suggests that both bodies carry a similar potential for narrative story-telling, and that their attraction is bound up with this narrative potential. The superhero and athlete live meaningful lives, pursuing clear and morally unambiguous goals. The aesthetic attraction of the body lies in its capacity to facilitate the articulation of a story of a meaningful life, and to do so in the face of the growing anomie and thus meaninglessness of life as experienced in contemporary society. Athleticism offers an illusion of meaning, serving to reproduce dominant justificatory narratives and social stereotypes. Yet, as an illusion of meaning, it may be challenged and negotiated, not least with respect to its bias towards a certain form of the male body. The female athletic body disrupts the illusion, opening up new existential possibilities, new ways of living and being, and thus new, and potentially disruptive, narratives.

Perceived impact of body feedback from romantic partners on young adults' body image and sexual well-being.

Science.gov (United States)

Goldsmith, Kaitlyn M; Byers, E Sandra

2016-06-01

This study investigated the messages individuals receive from their partners about their bodies and their perceived impact on body image and sexual well-being. Young adult men (n=35) and women (n=57) completed open-ended questions identifying messages they had received from partners and the impact of these messages on their body image and sexual well-being. Content coding revealed three verbal (expressions of approval and pride, challenging negative beliefs, expressions of sexual attraction/arousal/desire) and two nonverbal (physical affection, physical expressions of sexual attraction/arousal/desire) positive messages as well as one verbal (disapproval/disgust) and two nonverbal (rejection, humiliation) negative messages. Some participants reported gender-related messages (muscularity/strength, genital appearance, breast appearance, weight, and comparison to others). Positive messages were seen to increase confidence, self-acceptance, and sexual empowerment/fulfillment, whereas negative messages decreased these feelings. Our findings suggest that even everyday, seemingly neutral messages are perceived to have an important impact on young adults. Copyright © 2016 Elsevier Ltd. All rights reserved.

Configuration space methods in the three-nucleon problem

International Nuclear Information System (INIS)

Friar, J.L.

1985-01-01

The assumptions underlying the formulation and solution of the Schroedinger equation for three nucleons in configuration space are reviewed. Those qualitative aspects of the two-nucleon problem which play an important role in the trinucleon are discussed. The geometrical aspects of the problem are developed, and the importance of the angular momentum barrier is demonstrated. The Faddeev-Noyes formulation of the Schroedinger equation is motivated, and the boundary conditions for various three-body problems is reviewed. The method of splines is shown to provide a particularly useful numerical modelling technique for solving the Faddeev-Noyes equation. The properties of explicit trinucleon solutions for various two-body force models are discussed, and the evidence for three-body forces is reviewed. The status of calculations of trinucleon observables is discussed, and conclusions are presented. 40 refs., 14 figs

Hemispheric specialization in the assessment of female physical attractiveness.

Science.gov (United States)

Dural, Seda; Cetinkaya, Hakan; Gülbetekin, Evrim

2015-01-01

Female physical attractiveness has been widely related to waist-to-hip ratio (WHR) and body weight (BW). The present study was conducted to examine the role of hemispheric specialization in the perception of physical attractiveness. Drawings of female figures that differed in BW (underweight, normal and overweight) and WHR (0.7 and 1.0) were presented to both male and female subjects using the visual half-field technique. The stimuli were presented for an unusually short duration (180 msec). Under these conditions, male but not female subjects rated the various female figures as differing in attractiveness. Thus, male judgements of female attractiveness depended on weight and WHR. Reaction time and accuracy scores obtained from male subjects suggested that the left hemisphere (LH) was slower but more accurate than the right hemisphere in detecting differences in the attractiveness of the figures. Additionally, the most attractive figure was detected significantly more accurately than the least attractive figure when the figures were presented to the LH. The findings were discussed in terms of evolutionary views of sex differences in mate selection.

Body frames and frame singularities for three-atom systems

International Nuclear Information System (INIS)

Littlejohn, R.G.; Mitchell, K.A.; Aquilanti, V.; Cavalli, S.

1998-01-01

The subject of body frames and their singularities for three-particle systems is important not only for large-amplitude rovibrational coupling in molecular spectroscopy, but also for reactive scattering calculations. This paper presents a geometrical analysis of the meaning of body frame conventions and their singularities in three-particle systems. Special attention is devoted to the principal axis frame, a certain version of the Eckart frame, and the topological inevitability of frame singularities. The emphasis is on a geometrical picture, which is intended as a preliminary study for the more difficult case of four-particle systems, where one must work in higher-dimensional spaces. The analysis makes extensive use of kinematic rotations. copyright 1998 The American Physical Society

Using a whole body counter to attract a younger generation to radiation and radiation protection topics

International Nuclear Information System (INIS)

Breustedt, B.; Mohr, U.; Bohnstedt, A.; Knebel, J.U.

2010-01-01

Currently there is a lack of young academics in the nuclear field especially in the field of radiation protection RP. One of the reasons is the very small number of students in the so called STEM subjects (science, technology, engineering and mathematics) which distribute among the different topics in these fields. One important task to overcome the foreseeable shortage of RP professionals is to attract pupils to this field. In routine monitoring the whole body counter of the Institute of Radiation Research (ISF) is used to identify and quantify radioactive materials that are incorporated in the human body using the technique of gamma spectroscopy. The in-vivo monitoring lab participates in activities for pupils at school level, e.g. Kinderuniversitaet, practical studies of secondary level pupils and 'Girls day'. Pupils that come to the lab are ages 14 to 18. The whole body counter is an optimal tool for these children to experience (natural) radioactivity and radiation protection issues. First pupils get a short introduction on radioactivity and gamma spectroscopy at a level adjusted to their current knowledge. After this they are measuring themselves in the whole body counter. A routine measurement of 300 s is able to show the natural occurring K-40 in their bodies. After their own measurements they do calibration measurements using a bottle phantom with a set up adjusted to their own body weights. The bottle phantom is filled with a potassium chloride (KCl) solution and contains no other radioactivity than the natural K-40 content of the KCl. Thus no further radiation protection measures need to be taken for using this phantom. A simple Excel-Sheet is then used to estimate their own K-40 activity by comparing the spectra of their measurement to the ones of the calibration measurements. This 'hands on' experience and the connection of radiation and their own bodies often is a 'eureka' effect and opens discussion on preconceptions of radiation and the need of RP

Nuclear three-body problem and energy-dependent potentials

International Nuclear Information System (INIS)

Abdurakhmanov, A.; Akhmadkhodzhaev, B.; Zubarev, A.L.; Irgaziev, B.F.