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Sample records for partial molar entropy

  1. Molar heat capacity and entropy of calcium metal

    USGS Publications Warehouse

    Hemingway, B.S.; Robie, R.A.; Chase, M.W.

    1997-01-01

    The heat capacity of calcium has been measured at 85 mean temperatures between T ??? 8 K and T ??? 369 K using an adiabatically-shielded calorimeter in an intermittent heating mode. At T = 298.15 K, the recommended values for the molar heat capacity, molar entropy, and molar enthalpy increment referred to T = 0 are (25.77 ?? 0.08) J??K-1??mol-1, (42.90 ?? 0.11) J??K-1??mol-1, and (5811 ?? 12) J??mol-1, respectively. The uncertainties are twice the standard deviation of the mean. ?? 1997 Academic Press Limited.

  2. Hydrophobic effects on partial molar volume.

    PubMed

    Imai, Takashi; Hirata, Fumio

    2005-03-01

    The hydrophobic effects on partial molar volume (PMV) are investigated as a PMV change in the transfer of a benzenelike nonpolar solute from the nonpolar solvent to water, using an integral equation theory of liquids. The volume change is divided into two effects. One is the "packing" effect in the transfer from the nonpolar solvent to hypothetical "nonpolar water" without hydrogen bonding networks. The other is the "iceberg" effect in the transfer from nonpolar water to water. The results indicate that the packing effect is negative and a half compensated by the positive iceberg effect. The packing effect is explained by the difference in the solvent compressibility. Further investigation shows that the sign and magnitude of the volume change depend on the solute size and the solvent compressibility. The finding gives a significant implication that the exposure of a hydrophobic residue caused by protein denaturation can either increase or decrease the PMV of protein depending on the size of the residue and the fluctuation of its surroundings.

  3. Hydrophobic effects on partial molar volume

    NASA Astrophysics Data System (ADS)

    Imai, Takashi; Hirata, Fumio

    2005-03-01

    The hydrophobic effects on partial molar volume (PMV) are investigated as a PMV change in the transfer of a benzenelike nonpolar solute from the nonpolar solvent to water, using an integral equation theory of liquids. The volume change is divided into two effects. One is the "packing" effect in the transfer from the nonpolar solvent to hypothetical "nonpolar water" without hydrogen bonding networks. The other is the "iceberg" effect in the transfer from nonpolar water to water. The results indicate that the packing effect is negative and a half compensated by the positive iceberg effect. The packing effect is explained by the difference in the solvent compressibility. Further investigation shows that the sign and magnitude of the volume change depend on the solute size and the solvent compressibility. The finding gives a significant implication that the exposure of a hydrophobic residue caused by protein denaturation can either increase or decrease the PMV of protein depending on the size of the residue and the fluctuation of its surroundings.

  4. Partial molar quantity of an intensive mother function.

    PubMed

    Koga, Yoshikata

    2012-09-28

    A new formal definition is given to the partial molar quantity of a component i for an intensive mother function. We perturb the entire system by increasing the amount of the target component by δn(i) keeping others constant and measure the response of the system in terms of an intensive mother function, Φ, δΦ. We then define its partial molar quantity of the ith component, φ(i), as φ(i) = [δΦ∕{δn(i)∕(N + δn(i))

  5. Determination of partial molar volumes from free energy perturbation theory†

    PubMed Central

    Vilseck, Jonah Z.; Tirado-Rives, Julian

    2016-01-01

    Partial molar volume is an important thermodynamic property that gives insights into molecular size and intermolecular interactions in solution. Theoretical frameworks for determining the partial molar volume (V°) of a solvated molecule generally apply Scaled Particle Theory or Kirkwood–Buff theory. With the current abilities to perform long molecular dynamics and Monte Carlo simulations, more direct methods are gaining popularity, such as computing V° directly as the difference in computed volume from two simulations, one with a solute present and another without. Thermodynamically, V° can also be determined as the pressure derivative of the free energy of solvation in the limit of infinite dilution. Both approaches are considered herein with the use of free energy perturbation (FEP) calculations to compute the necessary free energies of solvation at elevated pressures. Absolute and relative partial molar volumes are computed for benzene and benzene derivatives using the OPLS-AA force field. The mean unsigned error for all molecules is 2.8 cm3 mol−1. The present methodology should find use in many contexts such as the development and testing of force fields for use in computer simulations of organic and biomolecular systems, as a complement to related experimental studies, and to develop a deeper understanding of solute–solvent interactions. PMID:25589343

  6. Characterization of Early Partial Seizure Onset: Frequency, Complexity and Entropy

    PubMed Central

    Jouny, Christophe C.; Bergey, Gregory K.

    2011-01-01

    Objective A clear classification of partial seizures onset features is not yet established. Complexity and entropy have been very widely used to describe dynamical systems, but a systematic evaluation of these measures to characterize partial seizures has never been performed. Methods Eighteen different measures including power in frequency bands up to 300Hz, Gabor atom density (GAD), Higuchi fractal dimension (HFD), Lempel-Ziv complexity, Shannon entropy, sample entropy, and permutation entropy, were selected to test sensitivity to partial seizure onset. Intracranial recordings from forty-five patients with mesial temporal, neocortical temporal and neocortical extratemporal seizure foci were included (331 partial seizures). Results GAD, Lempel-Ziv complexity, HFD, high frequency activity, and sample entropy were the most reliable measures to assess early seizure onset. Conclusions Increases in complexity and occurrence of high-frequency components appear to be commonly associated with early stages of partial seizure evolution from all regions. The type of measure (frequency-based, complexity or entropy) does not predict the efficiency of the method to detect seizure onset. Significance Differences between measures such as GAD and HFD highlight the multimodal nature of partial seizure onsets. Improved methods for early seizure detection may be achieved from a better understanding of these underlying dynamics. PMID:21872526

  7. Characterization of early partial seizure onset: frequency, complexity and entropy.

    PubMed

    Jouny, Christophe C; Bergey, Gregory K

    2012-04-01

    A clear classification of partial seizures onset features is not yet established. Complexity and entropy have been very widely used to describe dynamical systems, but a systematic evaluation of these measures to characterize partial seizures has never been performed. Eighteen different measures including power in frequency bands up to 300 Hz, Gabor atom density (GAD), Higuchi fractal dimension (HFD), Lempel-Ziv complexity, Shannon entropy, sample entropy, and permutation entropy, were selected to test sensitivity to partial seizure onset. Intracranial recordings from 45 patients with mesial temporal, neocortical temporal and neocortical extratemporal seizure foci were included (331 partial seizures). GAD, Lempel-Ziv complexity, HFD, high frequency activity, and sample entropy were the most reliable measures to assess early seizure onset. Increases in complexity and occurrence of high-frequency components appear to be commonly associated with early stages of partial seizure evolution from all regions. The type of measure (frequency-based, complexity or entropy) does not predict the efficiency of the method to detect seizure onset. Differences between measures such as GAD and HFD highlight the multimodal nature of partial seizure onsets. Improved methods for early seizure detection may be achieved from a better understanding of these underlying dynamics. Copyright © 2011 International Federation of Clinical Neurophysiology. Published by Elsevier Ireland Ltd. All rights reserved.

  8. Entropy and convexity for nonlinear partial differential equations.

    PubMed

    Ball, John M; Chen, Gui-Qiang G

    2013-12-28

    Partial differential equations are ubiquitous in almost all applications of mathematics, where they provide a natural mathematical description of many phenomena involving change in physical, chemical, biological and social processes. The concept of entropy originated in thermodynamics and statistical physics during the nineteenth century to describe the heat exchanges that occur in the thermal processes in a thermodynamic system, while the original notion of convexity is for sets and functions in mathematics. Since then, entropy and convexity have become two of the most important concepts in mathematics. In particular, nonlinear methods via entropy and convexity have been playing an increasingly important role in the analysis of nonlinear partial differential equations in recent decades. This opening article of the Theme Issue is intended to provide an introduction to entropy, convexity and related nonlinear methods for the analysis of nonlinear partial differential equations. We also provide a brief discussion about the content and contributions of the papers that make up this Theme Issue.

  9. Entropy and convexity for nonlinear partial differential equations

    PubMed Central

    Ball, John M.; Chen, Gui-Qiang G.

    2013-01-01

    Partial differential equations are ubiquitous in almost all applications of mathematics, where they provide a natural mathematical description of many phenomena involving change in physical, chemical, biological and social processes. The concept of entropy originated in thermodynamics and statistical physics during the nineteenth century to describe the heat exchanges that occur in the thermal processes in a thermodynamic system, while the original notion of convexity is for sets and functions in mathematics. Since then, entropy and convexity have become two of the most important concepts in mathematics. In particular, nonlinear methods via entropy and convexity have been playing an increasingly important role in the analysis of nonlinear partial differential equations in recent decades. This opening article of the Theme Issue is intended to provide an introduction to entropy, convexity and related nonlinear methods for the analysis of nonlinear partial differential equations. We also provide a brief discussion about the content and contributions of the papers that make up this Theme Issue. PMID:24249768

  10. Ethanol sorption and partial molar volume in cellulose acetate films

    SciTech Connect

    Bolton, B.A.; Kint, S.; Bailey, G.F.; Scherer, J.R.

    1986-03-13

    The absorption characteristics of cellulose acetate (CA398) and cellulose triacetate membranes for ethanol vapor were determined by integrated optical techniques. Changes in the refractive index and film thicknesses are used to calculate the ethanol concentration within the membrane, to calculate the partial molar volume of sorbed ethanol as a function of ethanol concentration, and to estimate the average void volume of the dry film. The refractive index is shown to be very sensitive to the available void space within the membrane. The average total void space for the films considered here was less than 1% of the dry polymer volume. 22 references, 6 figures, 1 table.

  11. Maximum entropy principle and partial probability weighted moments

    NASA Astrophysics Data System (ADS)

    Deng, Jian; Pandey, M. D.; Xie, W. C.

    2012-05-01

    Maximum entropy principle (MaxEnt) is usually used for estimating the probability density function under specified moment constraints. The density function is then integrated to obtain the cumulative distribution function, which needs to be inverted to obtain a quantile corresponding to some specified probability. In such analysis, consideration of higher ordermoments is important for accurate modelling of the distribution tail. There are three drawbacks for this conventional methodology: (1) Estimates of higher order (>2) moments from a small sample of data tend to be highly biased; (2) It can merely cope with problems with complete or noncensored samples; (3) Only probability weighted moments of integer orders have been utilized. These difficulties inevitably induce bias and inaccuracy of the resultant quantile estimates and therefore have been the main impediments to the application of the MaxEnt Principle in extreme quantile estimation. This paper attempts to overcome these problems and presents a distribution free method for estimating the quantile function of a non-negative randomvariable using the principle of maximum partial entropy subject to constraints of the partial probability weighted moments estimated from censored sample. The main contributions include: (1) New concepts, i.e., partial entropy, fractional partial probability weighted moments, and partial Kullback-Leibler measure are elegantly defined; (2) Maximum entropy principle is re-formulated to be constrained by fractional partial probability weighted moments; (3) New distribution free quantile functions are derived. Numerical analyses are performed to assess the accuracy of extreme value estimates computed from censored samples.

  12. Combinatorial entropy and phase diagram of partially ordered ice phases.

    PubMed

    Macdowell, Luis G; Sanz, Eduardo; Vega, Carlos; Abascal, José Luis F

    2004-11-22

    A close analytical estimate for the combinatorial entropy of partially ordered ice phases is presented. The expression obtained is very general, as it can be used for any ice phase obeying the Bernal-Fowler rules. The only input required is a number of crystallographic parameters, and the experimentally observed proton site occupancies. For fully disordered phases such as hexagonal ice, it recovers the result deduced by Pauling, while for fully ordered ice it is found to vanish. Although the space groups determined for ice I, VI, and VII require random proton site occupancies, it is found that such random allocation of protons does not necessarily imply random orientational disorder. The theoretical estimate for the combinatorial entropy is employed together with free energy calculations in order to obtain the phase diagram of ice from 0 to 10 GPa. Overall qualitative agreement with experiment is found for the TIP4P model of water. An accurate estimate of the combinatorial entropy is found to play an important role in determining the stability of partially ordered ice phases, such as ice III and ice V.

  13. Partial moment entropy approximation to radiative heat transfer

    SciTech Connect

    Frank, Martin . E-mail: frank@mathematik.uni-kl.de; Dubroca, Bruno . E-mail: Bruno.Dubroca@math.u-bordeaux.fr; Klar, Axel . E-mail: klar@mathematik.uni-kl.de

    2006-10-10

    We extend the half moment entropy closure for the radiative heat transfer equations presented in Dubroca and Klar [B. Dubroca, A. Klar, Half moment closure for radiative transfer equations, J. Comput. Phys. 180 (2002) 584-596] and Turpault et al. [R. Turpault, M. Frank, B. Dubroca, A. Klar, Multigroup half space moment approximations to the radiative heat transfer equations, J. Comput. Phys. 198 (2004) 363-371] to multi-D. To that end, we consider a partial moment system with general partitions of the unit sphere closed by an entropy minimization principle. We give physical and mathematical reasons for this choice of model and study its properties. Several numerical examples in different physical regimes are presented.

  14. Solubility and partial molar volumes of heavy aromatic hydrocarbons in supercritical CO/sub 2/

    SciTech Connect

    Mitra, S.; Chen, J.W.; Viswanath, D.S.

    1988-01-01

    Isothermal solubility data of naphthalene, dibenzothiophene, and mixture of naphthalene + dibenzothiophene in supercritical CO/sub 2/ were measured over a pressure range of 75-275 bar. The solubility data have been used to calculate the partial molar volumes. The calculated partial molar volumes of naphthalene in supercritical CO/sub 2/ have been compared with the experimental values available in the literature. The calculated values are in good agreement with the experimental values available in the literature.

  15. The Component Slope Linear Model for Calculating Intensive Partial Molar Properties: Application to Waste Glasses

    SciTech Connect

    Reynolds, Jacob G.

    2013-01-11

    Partial molar properties are the changes occurring when the fraction of one component is varied while the fractions of all other component mole fractions change proportionally. They have many practical and theoretical applications in chemical thermodynamics. Partial molar properties of chemical mixtures are difficult to measure because the component mole fractions must sum to one, so a change in fraction of one component must be offset with a change in one or more other components. Given that more than one component fraction is changing at a time, it is difficult to assign a change in measured response to a change in a single component. In this study, the Component Slope Linear Model (CSLM), a model previously published in the statistics literature, is shown to have coefficients that correspond to the intensive partial molar properties. If a measured property is plotted against the mole fraction of a component while keeping the proportions of all other components constant, the slope at any given point on a graph of this curve is the partial molar property for that constituent. Actually plotting this graph has been used to determine partial molar properties for many years. The CSLM directly includes this slope in a model that predicts properties as a function of the component mole fractions. This model is demonstrated by applying it to the constant pressure heat capacity data from the NaOH-NaAl(OH{sub 4}H{sub 2}O system, a system that simplifies Hanford nuclear waste. The partial molar properties of H{sub 2}O, NaOH, and NaAl(OH){sub 4} are determined. The equivalence of the CSLM and the graphical method is verified by comparing results detennined by the two methods. The CSLM model has been previously used to predict the liquidus temperature of spinel crystals precipitated from Hanford waste glass. Those model coefficients are re-interpreted here as the partial molar spinel liquidus temperature of the glass components.

  16. Studies of enthalpy-entropy compensation, partial entropies, and Kirkwood-Buff integrals for aqueous solutions of glycine, L-leucine, and glycylglycine at 298.15 K.

    PubMed

    Kurhe, Deepti N; Dagade, Dilip H; Jadhav, Jyoti P; Govindwar, Sanjay P; Patil, Kesharsingh J

    2009-12-31

    Densities and osmotic coefficient measurements for dilute aqueous solutions of glycine, l-leucine, and glycylglycine have been reported at 298.15 K. The partial molar volumes and activity coefficients of solute as well as solvent have been estimated using the density and osmotic coefficient data, respectively. Excess and mixing thermodynamic properties, such as Gibbs free energy, enthalpy, and entropy changes, have been obtained using the activity data from this study and the heat data reported in the literature. The concentration enthalpy-entropy compensation effects have been observed for the studied systems, and the compensation temperatures are reported. It has been observed that the excess free energy change for all the studied systems is almost the same over the studied concentration range, showing that the differences in properties of such solutions are largely decided by the enthalpy-entropy effects. These results, along with partial entropy data, show the effects of the presence of hydrophobic interactions and water structure making effect in the case of aqueous solutions of l-leucine. The application of the Starikov-Norden enthalpy-entropy compensation model yielded information about a "hidden Carnot cycle" and the existence of multiple microphases. Application of the Kirkwood-Buff (KB) theory of solutions for the studied systems yields pair correlation functions between the components. The variation of Kirkwood-Buff integrals with concentration further signifies the concentration dependence of the hydrophobic hydration and interactions in the solution phase. The osmotic second virial coefficients have also been obtained using the KB theory and show good agreement with those obtained using the McMillan-Mayer theory of solutions. The mean square concentration fluctuations is estimated using the KB theory, which gives information about the microheterogeneity in the solution phase, which further reflects the presence of hydration and solute association.

  17. Partial distortion entropy maximization for online data clustering.

    PubMed

    Takizawa, Hiroyuki; Kobayashi, Hiroaki

    2007-09-01

    Competitive learning neural networks are regarded as a powerful tool for online data clustering to represent a non-stationary probability distribution with a fixed number of weight vectors. One difficulty in practical applications of competitive learning neural networks to online data clustering is that most of them require heuristically-predetermined threshold parameters for balancing a trade-off between convergence accuracy, i.e. error minimization performance, and speed of adaptation to the changes in source statistics. Although adaptation acceleration is achievable by relocating a "useless" node so that it becomes useful, excessive relocation often disturbs error minimization. Hence, both of the adaptation speed and the error minimization performance sensitively depend on threshold parameters to determine whether a node should be relocated or not. In general, it is difficult to know adequate threshold parameters a priori. This paper proposes a novel criterion for decision making of node relocation without heuristically predetermined thresholds. According to the proposed criterion, a node is relocated only if the relocation task improves partial distortion entropy, which is an online optimality metric reliable from the viewpoint of error minimization. Hence, node relocation is carried out without disturbing error minimization. As a result, both quick adaptation and error minimization are simultaneously accomplished without any carefully predefined parameters. Experimental results clarify the validity of the proposed criterion. Competitive learning with the criterion is clearly superior to other representative algorithms in terms of both quick adaptation and error minimization performance.

  18. Association between the presence of a partially erupted mandibular third molar and the existence of caries in the distal of the second molars.

    PubMed

    Falci, S G M; de Castro, C R; Santos, R C; de Souza Lima, L D; Ramos-Jorge, M L; Botelho, A M; Dos Santos, C R R

    2012-10-01

    The objective of this study was to verify, using periapical radiographs, whether a partially erupted mandibular third molar is a factor in the presence of dental caries on the distal surface of the adjacent second molar. Two-forty six high quality periapical radiographs were selected, each showing a partially erupted mandibular third molar. The variables analyzed were: tooth number; gender; age; radiographic presence of caries on the distal surface of the adjacent molar; Pell and Gregory classification; Winter classification; angulation and distance between the second and mandibular third molar. The examiners were previously calibrated to collect data (kappa statistics from 0.87 to 1.0). The prevalence rate of caries on the distal surface of the second molar was 13.4%. In the logistical multivariate regression analysis, the angulation (OR=8.5; IC95%: 1.7-43.8; p=0.011) and the gender (OR=3.3; IC95%: 1.4-7.7; p=0.005) remained statistically significant after an age adjustment was made. The results indicate that the presence of a partially erupted mandibular third molar with an angulation of 31 degrees or more, is a risk factor for caries on the distal surface of the mandibular second molars. Copyright © 2012 International Association of Oral and Maxillofacial Surgeons. Published by Elsevier Ltd. All rights reserved.

  19. Thermodynamics of liquids: standard molar entropies and heat capacities of common solvents from 2PT molecular dynamics.

    PubMed

    Pascal, Tod A; Lin, Shiang-Tai; Goddard, William A

    2011-01-07

    We validate here the Two-Phase Thermodynamics (2PT) method for calculating the standard molar entropies and heat capacities of common liquids. In 2PT, the thermodynamics of the system is related to the total density of states (DoS), obtained from the Fourier Transform of the velocity autocorrelation function. For liquids this DoS is partitioned into a diffusional component modeled as diffusion of a hard sphere gas plus a solid component for which the DoS(υ) → 0 as υ→ 0 as for a Debye solid. Thermodynamic observables are obtained by integrating the DoS with the appropriate weighting functions. In the 2PT method, two parameters are extracted from the DoS self-consistently to describe diffusional contributions: the fraction of diffusional modes, f, and DoS(0). This allows 2PT to be applied consistently and without re-parameterization to simulations of arbitrary liquids. We find that the absolute entropy of the liquid can be determined accurately from a single short MD trajectory (20 ps) after the system is equilibrated, making it orders of magnitude more efficient than commonly used perturbation and umbrella sampling methods. Here, we present the predicted standard molar entropies for fifteen common solvents evaluated from molecular dynamics simulations using the AMBER, GAFF, OPLS AA/L and Dreiding II forcefields. Overall, we find that all forcefields lead to good agreement with experimental and previous theoretical values for the entropy and very good agreement in the heat capacities. These results validate 2PT as a robust and efficient method for evaluating the thermodynamics of liquid phase systems. Indeed 2PT might provide a practical scheme to improve the intermolecular terms in forcefields by comparing directly to thermodynamic properties.

  20. Symptoms and lesions associated with retained or partially erupted third molars. Some variables of third-molar surgery in Norwegian general practice.

    PubMed

    Berge, T I; Bøe, O E

    1993-04-01

    A questionnaire on third-molar problems was mailed to a systematic random sample of 200 Norwegian general dental practitioners in November 1991. A 88% return rate was obtained. The following conclusions were drawn: on an average, 3.8 patients with lesions or complaints from retained or partially erupted third molars were seen in general practice in 1 month, and most of these consultations were associated with partially erupted third molars. A mean of 1.3 surgical removals of third molars was performed in general practice in 1 month. The mean one-way travel time for patients to specialists in oral surgery was 1.3 h, and variations were not related to surgical activity in practice. Fourteen per cent of the general practitioners refer surgical cases to non-specialists.

  1. Risk of recurrent molar pregnancies following complete and partial hydatidiform moles.

    PubMed

    Eagles, N; Sebire, N J; Short, D; Savage, P M; Seckl, M J; Fisher, R A

    2015-09-01

    What is the risk of further molar pregnancies for women with one or more hydatidiform moles (HM) in relation to molar subtype. Women with a complete hydatidiform mole (CM) have a 1 in 100 and 1 in 4 risk of further CM after one or two consecutive CM, respectively, while women with a partial hydatidiform mole (PM) have only a small increase in risk for further molar pregnancies. Women with a molar pregnancy have an increased risk of further HM. A small subgroup of women with recurrent HM has an autosomal recessive condition, familial recurrent hydatidiform moles (FRHM), that predisposes them to molar pregnancies. A retrospective study of subsequent pregnancies in 16 000 women registered at a centralized referral centre, with a CM or PM, between 1990 and 2009. One hundred and sixty-six women with two or more molar pregnancies were identified from electronic records and patient notes. Histopathological features of all molar tissue were reviewed in these cases and genotyping performed where diagnosis was not possible on the basis of histopathological features alone. In addition, genotyping of molar tissue was performed in all cases of women with three or more CM to establish whether the tissue was diploid and biparental or androgenetic. This study confirms an increased recurrence risk of ∼1% for a second molar pregnancy and in addition that this risk is associated with CM rather than PM. The data further indicate that the risk of a third HM is associated almost exclusively with CM and enabled an estimate that 1 in 640 women registered with a CM has the rare condition FRHM. The study also found that there was no significant difference between the risk of developing gestational trophoblastic neoplasia (GTN) for typical sporadic CM and the diploid biparental CM associated with FRHM (GTN; proportion difference 0.05, Z = 0.87, P = 0.29). While pathology was reviewed for all women with two or more molar pregnancies, not all cases registered underwent central review

  2. Effect of fluoride varnish on caries prevention of partially erupted of permanent molar in high caries risk.

    PubMed

    Suwansingha, Orawan; Rirattanapong, Praphasri

    2012-05-01

    The objective of this study was to measure the effectiveness of fluoride varnish as a public health intervention to prevent caries on partially erupted first and second permanent molars among 6-11 year old children at high risk for caries. In a six-month clinical trial, 105 children were randomly divided into a fluoride varnish (Duraphat) group (117 molars) or a control group (117 molars). The chi-square test used to compare caries occurrence in each group with a 95% level of confidence (p<0.05) at the intervals of 3 months. Compared to control, fluoride varnish resulted in 79% and 77.5% caries reduction in partially erupted permanent molars at 3 and 6 months, respectively. There were statistically significant differences in caries progression between the groups at 3 and 6 months. Fluoride varnish significantly reduced carious lesions in partially erupted molars at six months among high caries risk children.

  3. Subsequent pregnancy outcomes after complete and partial molar pregnancy, recurrent molar pregnancy, and gestational trophoblastic neoplasia: an update from the New England Trophoblastic Disease Center.

    PubMed

    Vargas, Roberto; Barroilhet, Lisa M; Esselen, Katharine; Diver, Elisabeth; Bernstein, Marilyn; Goldstein, Donald P; Berkowitz, Ross S

    2014-01-01

    To review and update the subsequent reproductive outcomes in patients with complete, partial, and recurrent hydatidiform moles, as well as gestational trophoblastic neoplasia (GTN) at the New England Trophoblastic Disease Center. Patients with complete and partial hydatidiform mole, recurrent hydatidiform mole, and GTN were identified from the Donald P. Goldstein, M.D., Trophoblastic Tumor Registry. Questionnaires regarding subsequent pregnancies were mailed to patients with current mailing addresses available. Additional patient data was obtained from electronic medical records. A total of 2,432 subsequent pregnancies have been reported since 1965. Of those, 1,388 pregnancies were after complete mole, 357 after partial mole, and 667 after GTN. The subsequent reproductive outcomes in patients with complete and partial molar pregnancies and persistent GTN remain similar to those in the general population. However, approximately 1.7% of patients with a prior molar pregnancy had a molar pregnancy in a later gestation. Furthermore, after successful chemotherapy for GTN the incidence of stillbirth was slightly increased to 1.3% in later pregnancies. Patients with molar pregnancies and GTN should expect similar reproductive outcomes as compared to the general population. However, patients receiving chemotherapy for GTN have a slightly increased risk stillbirth in subsequent pregnancies.

  4. Note: Nonpolar solute partial molar volume response to attractive interactions with water.

    PubMed

    Williams, Steven M; Ashbaugh, Henry S

    2014-01-07

    The impact of attractive interactions on the partial molar volumes of methane-like solutes in water is characterized using molecular simulations. Attractions account for a significant 20% volume drop between a repulsive Weeks-Chandler-Andersen and full Lennard-Jones description of methane interactions. The response of the volume to interaction perturbations is characterized by linear fits to our simulations and a rigorous statistical thermodynamic expression for the derivative of the volume to increasing attractions. While a weak non-linear response is observed, an average effective slope accurately captures the volume decrease. This response, however, is anticipated to become more non-linear with increasing solute size.

  5. Note: Nonpolar solute partial molar volume response to attractive interactions with water

    SciTech Connect

    Williams, Steven M.; Ashbaugh, Henry S.

    2014-01-07

    The impact of attractive interactions on the partial molar volumes of methane-like solutes in water is characterized using molecular simulations. Attractions account for a significant 20% volume drop between a repulsive Weeks-Chandler-Andersen and full Lennard-Jones description of methane interactions. The response of the volume to interaction perturbations is characterized by linear fits to our simulations and a rigorous statistical thermodynamic expression for the derivative of the volume to increasing attractions. While a weak non-linear response is observed, an average effective slope accurately captures the volume decrease. This response, however, is anticipated to become more non-linear with increasing solute size.

  6. Thermodynamic studies of aqueous solutions of 2,2,2-cryptand at 298.15 K: enthalpy-entropy compensation, partial entropies, and complexation with K+ ions.

    PubMed

    Shaikh, Vasim R; Terdale, Santosh S; Ahamad, Abdul; Gupta, Gaurav R; Dagade, Dilip H; Hundiwale, Dilip G; Patil, Kesharsingh J

    2013-12-19

    The osmotic coefficient measurements for binary aqueous solutions of 2,2,2-cryptand (4,7,13,16,21,24-hexaoxa-1,10-diazabicyclo[8.8.8] hexacosane) in the concentration range of ~0.009 to ~0.24 mol·kg(-1) and in ternary aqueous solutions containing a fixed concentration of 2,2,2-cryptand of ~0.1 mol·kg(-1) with varying concentration of KBr (~0.06 to ~0.16 mol·kg(-1)) have been reported at 298.15 K. The diamine gets hydrolyzed in aqueous solutions and needs proper approach to obtain meaningful thermodynamic properties. The measured osmotic coefficient values are corrected for hydrolysis and are used to determine the solvent activity and mean ionic activity coefficients of solute as a function of concentration. Strong ion-pair formation is observed, and the ion-pair dissociation constant for the species [CrptH](+)[OH(-)] is reported. The excess and mixing thermodynamic properties (Gibbs free energy, enthalpy, and entropy changes) have been obtained using the activity data from this study and the heat data reported in the literature. Further, the data are utilized to compute the partial molal entropies of solvent and solute at finite as well as infinite dilution of 2,2,2-cryptand in water. The concentration dependent non-linear enthalpy-entropy compensation effect has been observed for the studied system, and the compensation temperature along with entropic parameter are reported. Using solute activity coefficient data in ternary solutions, the transfer Gibbs free energies for transfer of the cryptand from water to aqueous KBr as well as transfer of KBr from water to aqueous cryptand were obtained and utilized to obtain the salting constant (ks) and thermodynamic equilibrium constant (log K) values for the complex (2,2,2-cryptand:K(+)) at 298.15 K. The value of log K = 5.8 ± 0.1 obtained in this work is found to be in good agreement with that reported by Lehn and Sauvage. The standard molar entropy for complexation is also estimated for the 2,2,2-cryptand

  7. The component slope linear model for calculating intensive partial molar properties /application to waste glasses and aluminate solutions

    SciTech Connect

    Reynolds, Jacob G.

    2013-01-11

    Partial molar properties are the changes occurring when the fraction of one component is varied while the fractions of all other component mole fractions change proportionally. They have many practical and theoretical applications in chemical thermodynamics. Partial molar properties of chemical mixtures are difficult to measure because the component mole fractions must sum to one, so a change in fraction of one component must be offset with a change in one or more other components. Given that more than one component fraction is changing at a time, it is difficult to assign a change in measured response to a change in a single component. In this study, the Component Slope Linear Model (CSLM), a model previously published in the statistics literature, is shown to have coefficients that correspond to the intensive partial molar properties. If a measured property is plotted against the mole fraction of a component while keeping the proportions of all other components constant, the slope at any given point on a graph of this curve is the partial molar property for that constituent. Actually plotting this graph has been used to determine partial molar properties for many years. The CSLM directly includes this slope in a model that predicts properties as a function of the component mole fractions. This model is demonstrated by applying it to the constant pressure heat capacity data from the NaOH-NaAl(OH){sub 4}-H{sub 2}O system, a system that simplifies Hanford nuclear waste. The partial molar properties of H{sub 2}O, NaOH, and NaAl(OH){sub 4} are determined. The equivalence of the CSLM and the graphical method is verified by comparing results determined by the two methods. The CSLM model has been previously used to predict the liquidus temperature of spinel crystals precipitated from Hanford waste glass. Those model coefficients are re-interpreted here as the partial molar spinel liquidus temperature of the glass components.

  8. Hydrophobic hydration and the anomalous partial molar volumes in ethanol-water mixtures

    SciTech Connect

    Tan, Ming-Liang; Te, Jerez; Cendagorta, Joseph R.; Miller, Benjamin T.; Brooks, Bernard R.; Ichiye, Toshiko

    2015-02-14

    The anomalous behavior in the partial molar volumes of ethanol-water mixtures at low concentrations of ethanol is studied using molecular dynamics simulations. Previous work indicates that the striking minimum in the partial molar volume of ethanol V{sub E} as a function of ethanol mole fraction X{sub E} is determined mainly by water-water interactions. These results were based on simulations that used one water model for the solute-water interactions but two different water models for the water-water interactions. This is confirmed here by using two more water models for the water-water interactions. Furthermore, the previous work indicates that the initial decrease is caused by association of the hydration shells of the hydrocarbon tails, and the minimum occurs at the concentration where all of the hydration shells are touching each other. Thus, the characteristics of the hydration of the tail that cause the decrease and the features of the water models that reproduce this type of hydration are also examined here. The results show that a single-site multipole water model with a charge distribution that mimics the large quadrupole and the p-orbital type electron density out of the molecular plane has “brittle” hydration with hydrogen bonds that break as the tails touch, which reproduces the deep minimum. However, water models with more typical site representations with partial charges lead to flexible hydration that tends to stay intact, which produces a shallow minimum. Thus, brittle hydration may play an essential role in hydrophobic association in water.

  9. Fracture resistance of different partial-coverage ceramic molar restorations: An in vitro investigation.

    PubMed

    Stappert, Christian F J; Att, Wael; Gerds, Thomas; Strub, Joerg R

    2006-04-01

    The authors conducted a study to evaluate the influence of preparation design on reliability and fracture resistance of press-ceramic posterior partial-coverage restorations (PCRs) under fatigue. They compared the results for PCRs fabricated of a new press ceramic (IPS e.max Press-VP 1989/4, Ivoclar-Vivadent, Schaan, Liechtenstein) with results for ceramic inlays and unprepared molars. The authors randomly divided 96 human upper molars into six equal groups. Control group NP specimens remained unprepared. Control group IN specimens received a mesio-occlusal-distal (MOD) inlay preparation. The test groups received PCR preparation designs based on group IN's inlay design, with additional cuspal reduction that increased from group to group. The authors fabricated 16 ceramic inlays and 64 PCRs of IPS e.max Press and luted them adhesively. All specimens underwent masticatory fatigue loading (1.2 million cycles, 1.6 hertz, 98 newtons), 5,300 thermal cycles and observation for fracture patterns. Afterward, the authors loaded all surviving specimens until fracture. No fractures occurred during the exposure to the masticatory simulation. After undergoing loading in a universal testing machine, the groups showed no significant differences in fracture strength values (P = .6026). Thus, the different preparation designs of the PCRs demonstrated no significant influence on the restorations' fracture resistance. The median failure loads ranged from 1,567 to 1,960 newtons. All-ceramic PCRs for molars made of IPS e.max Press were shown to be fracture-resistant, results comparable with those of natural unprepared teeth. When a posterior ceramic PCR is indicated, the clinician should perform a defect-oriented preparation that preserves tooth structure. Further clinical investigations are recommended to verify the authors' in vitro results.

  10. Partial molar enthalpies and reaction enthalpies from equilibrium molecular dynamics simulation

    SciTech Connect

    Schnell, Sondre K.; Skorpa, Ragnhild; Bedeaux, Dick; Kjelstrup, Signe; Vlugt, Thijs J. H.; Simon, Jean-Marc

    2014-10-14

    We present a new molecular simulation technique for determining partial molar enthalpies in mixtures of gases and liquids from single simulations, without relying on particle insertions, deletions, or identity changes. The method can also be applied to systems with chemical reactions. We demonstrate our method for binary mixtures of Weeks-Chandler-Anderson particles by comparing with conventional simulation techniques, as well as for a simple model that mimics a chemical reaction. The method considers small subsystems inside a large reservoir (i.e., the simulation box), and uses the construction of Hill to compute properties in the thermodynamic limit from small-scale fluctuations. Results obtained with the new method are in excellent agreement with those from previous methods. Especially for modeling chemical reactions, our method can be a valuable tool for determining reaction enthalpies directly from a single MD simulation.

  11. How big is the hydrated electron? Thermodynamics of electron solvation and its partial molar volume

    NASA Astrophysics Data System (ADS)

    Bartels, David

    2015-03-01

    Several models for the hydrated electron solvation structure have been proposed, which all can do a reasonable job of reproducing the room temperature optical spectrum. As Larsen, Glover and Schwartz demonstrated, tweaking the electron-water pseudopotential can completely change the structure from a cavity to a non-cavity geometry. Deciding between the competing models then requires comparison with other observables. The resonance Raman spectrum and the temperature dependence of the optical spectrum can be cited as evidence in favor of a non-cavity structure. In the present work we will re-examine the thermodynamics of hydration. In particular, we will present new experimental and simulation results for the partial molar volume, which can bear directly on the cavity vs. non-cavity controversy. DMB is supported by the U.S. Department of Energy Office of Science, Office of Basic Energy Sciences under Award Number DE- FC02-04ER1553.

  12. Unilateral rotational path removable partial dentures for tilted mandibular molars: design and clinical applications.

    PubMed

    Luk, K; Tsai, T; Hsu, S; Wang, F L

    1997-07-01

    This article describes the design of a unilateral rotational path removable partial denture to restore a single edentulous space with a tilted mandibular molar. It is modified from an original bilateral rotational path design and consists of several components, which are (1) the rotation axis, (2) the long occlusal rest, (3) the short bracing arms, (4) the rigid retainer and extended proximal plates, (5) the conventional direct retainer assembly, and (6) optional auxiliary rest. The stability and retention of the denture are controlled anteriorly by the buccal retentive clasp and lingual guide plate of the conventional direct retainer, and posteriorly by the rigid retainer and its buccally and lingually extended proximal plates. The clinical results of the dentures used in strictly selected situations are excellent; however, it is emphasized that a unilateral denture is only an alternative rather than a routine application. The risk of accidental aspiration is also of concern.

  13. Spectrum of excess partial molar absorptivity. Part II: a near infrared spectroscopic study of aqueous Na-halides.

    PubMed

    Sebe, Fumie; Nishikawa, Keiko; Koga, Yoshikata

    2012-04-07

    Our earlier thermodynamic studies suggested that F(-) and Cl(-) form hydration shells with the hydration number 14 ± 2 and 2.3 ± 0.6, respectively, and leave the bulk H(2)O away from hydration shells unperturbed. Br(-) and I(-), on the other hand, form hydrogen bonds directly with the momentarily existing hydrogen bond network of H(2)O, and retard the degree of entropy-volume cross fluctuation inherent in liquid H(2)O. The effect of the latter is stronger for I(-) than Br(-). Here we seek additional information about this qualitative difference between Cl(-) and (Br(-) and I(-)) pair by near infrared (NIR) spectroscopy. We analyze the ν(2) + ν(3) band of H(2)O in the range 4600-5500 cm(-1) of aqueous solutions of NaCl, NaBr and NaI, by a new approach. From observed absorbance, we calculate excess molar absorptivity, ε(E), excess over the additive contributions of solute and solvent. ε(E) thus contains information about the effect of inter-molecular interactions in the ν(2) + ν(3) spectrum. The spectrum of ε(E) shows three bands; two negative ones at 5263 and 4873 cm(-1), and the positive band at 5123 cm(-1). We then define and calculate the excess partial molar absorptivity of each salt, ε(E)(salt). From the behaviour of ε(E)(salt) we suggest that the negative band at 5263 cm(-1) represents free H(2)O without much hydrogen bonding under the influence of local electric field of ions. Furthermore, from a sudden change in the x(salt) (mole fraction of salt) dependence of ε(E)(salt), we suggest that there is an ion-pairing in x(salt) > 0.032, 0.036, and 0.04 for NaCl, NaBr and NaI respectively. The positive band of ε(E) at 5123 cm(-1) is attributed to a modestly organized hydrogen bond network of H(2)O (or liquid-likeness), and the x(salt) dependence of ε indicated a qualitative difference in the effect of Cl(-) from those of Br(-) and I(-). Namely, the values of ε(E)(salt) stay constant for Cl(-) but those for Br(-) and I(-) decrease smoothly on

  14. Sealing versus partial caries removal in primary molars: a randomized clinical trial

    PubMed Central

    2014-01-01

    Background The resin-based pit and fissure sealant is considered a successful tool in caries prevention, however there is a growing evidence of its use in controlling already established caries in posterior teeth. The aim of this clinical trial is to verify the efficacy of pit and fissure sealants in arresting dentinal caries lesions compared to partial excavation and restorative treatment in primary molar teeth. Methods Thirty six patients with occlusal cavitated primary molar reaching outer half of dentin were selected. The patients were randomly allocated into two groups: sealant application (experimental group – n = 17) and restoration with composite resin (control group – n = 19). Clinical and radiograph evaluation were performed after 6, 12 and 18 months. The chi-square test was used to verify the distribution of characteristics variables of the sample among the groups. The survival rate of treatments was evaluated using Kaplan–Meier survival and log-rank test. Fisher’s Exact and logistic regression tests were calculated in each evaluation period (α = 5%). Results The control group showed significantly better clinical survival after 18 months (p = 0.0025). In both groups, no caries progression was registered on the radiographic evaluations. Conclusions Sealing had similar efficacy in the arrestment of caries progression of cavitated occlusal lesions compared to partial excavation of the lesions, even though the frequency of re-treatments was significantly higher in sealed lesions. Trial registration Registro Brasileiro de Ensaios Clínicos (ReBEC): RBR-9kkv53 PMID:24884684

  15. Determination of conformational entropy of fully and partially folded conformations of holo- and apomyoglobin.

    PubMed

    Stadler, Andreas M; Koza, Michael Marek; Fitter, Jörg

    2015-01-08

    Holo- and apomyoglobin can be stabilized in native folded, partially folded molten globules (MGs) and denatured states depending on the solvent composition. Although the protein has been studied as a model system in the field of protein folding, little is known about the internal dynamics of the different structural conformations on the picosecond time scale. In a comparative experimental study we investigated the correlation between protein folding and dynamics on the picosecond time scale using incoherent quasielastic neutron scattering (QENS). The measured mean square displacements (MSDs) of conformational motions depend significantly on the secondary structure content of the protein, whereas the correlation times of the observed internal dynamics were found to be similar irrespective of the degree of folding. The conformational entropy difference ΔSconf between the folded conformations and the acid denatured state could be determined from the measured MSDs and was compared to the entropy difference ΔS obtained from thermodynamic parameters reported in the literature. The observed difference between ΔS and ΔSconf was attributed to the entropy difference ΔShydr of dynamically disordered water molecules of the hydration shell. The entropy content of the hydration water is significantly larger in the native folded proteins than in the partially folded MGs. We demonstrate the potential of incoherent neutron scattering for the investigation of the role of conformational dynamics in protein folding.

  16. Infinite dilution partial molar volumes of platinum(II) 2,4-pentanedionate in supercritical carbon dioxide.

    PubMed

    Kong, Chang Yi; Siratori, Tomoya; Funazukuri, Toshitaka; Wang, Guosheng

    2014-10-03

    The effects of temperature and density on retention of platinum(II) 2,4-pentanedionate in supercritical fluid chromatography were investigated at temperatures of 308.15-343.15K and pressure range from 8 to 40MPa by the chromatographic impulse response method with curve fitting. The retention factors were utilized to derive the infinite dilution partial molar volumes of platinum(II) 2,4-pentanedionate in supercritical carbon dioxide. The determined partial molar volumes were small and positive at high pressures but exhibited very large and negative values in the highly compressible near critical region of carbon dioxide.

  17. Apparent molar and partial molar volumes of aqueous ceric ammonium nitrate solutions at 20, 25, 30, and 35°C

    NASA Astrophysics Data System (ADS)

    Deosarkar, S. D.; Wanale, S. G.; Shelke, M. P.

    2014-07-01

    Present paper reports the measured densities (ρ) and refractive indices ( n D) of aqueous solutions of ceric ammonium nitrate (CAN) at 20, 25, 30, and 35°C in different concentrations of solution. Apparent molar volumes (φv) have been calculated from the density data at different temperatures and fitted to Massons relation to get limiting partial molar volumes (ϕ{v/0}) of CAN. Refractive index data were fitted to linear dependence over concentration of solutions and values of constant K and n {D/0} for different temperatures were evaluated. Specific refractions ( R D) of solutions were calculated from the refractive index and density data. Concentration and temperature effects on experimental and derived properties have been discussed in terms of structural interactions.

  18. Partial molar volumes and viscous properties of glycine-aqueous urea solutions at 298.15 K

    NASA Astrophysics Data System (ADS)

    Deosarkar, S. D.; Ban, A. R.; Tawde, P. D.; Sawale, R. T.

    2015-07-01

    Density (ρ) and viscosity (η) of glycine ( c = 0.02-0.22 mol dm-3) in aqueous urea ( c = 0.5, 1.5, and 3.0 mol dm-3) solutions were measured at 298.15 K. Experimental density data has been used to calculate apparent molar volumes (φv) of glycine in aqueous and aqueous-urea solutions at 298.15 K. The dependence of apparent molar volumes on concentration of glycine was fitted to the Massons relation and apparent molar volume of glycine at infinite dilution (partial molar volume, φ{v/0}) was determined graphically. The partial molar volumes of transfer (Δtrφ{v/0}) of glycine at infinite dilution from pure water to aqueous-urea solutions at 298.15 K were calculated and interpreted in terms of various interactions and structural fittings in studied solutions. The relative viscosity data has been analyzed by Jones-Dole relation and viscosity B-coefficients were determined graphically. Viscosity B-coefficient of transfer (Δ B) was also calculated and compared with Δtrφ{v/0}.

  19. Spectrum of excess partial molar absorptivity. I. Near infrared spectroscopic study of aqueous acetonitrile and acetone.

    PubMed

    Koga, Yoshikata; Sebe, Fumie; Minami, Takamasa; Otake, Keiko; Saitow, Ken-ichi; Nishikawa, Keiko

    2009-09-03

    We study the mixing schemes or the molecular processes occurring in aqueous acetonitrile (ACN) and acetone (ACT) by near-infrared spectroscopy (NIR). Both solutions (any other aqueous solutions) are not free from strong and complex intermolecular interactions. To tackle such a many-body problem, we first use the concept of the excess molar absorptivity, epsilonE, which is a function of solute mole fraction in addition to that of wavenumber, nu. The plots of epsilonE calculated from NIR spectra for both aqueous solutions against nu showed two clearly separated bands at 5020 and 5230 cm(-1); the former showed negative and the latter positive peaks. At zero and unity mole fractions of solute, epsilonE is identically zero independent of nu. Similar to the thermodynamic excess functions, both negative and positive bands grow in size from zero to the minimum (or the maximum) and back to zero, as the mole fraction varies from 0 to 1. Since the negative band's nu-locus coincides with the NIR spectrum of ice, and the positive with that of liquid H(2)O, we suggest that on addition of solute the "ice-likeness" decreases and the "liquid-likeness" increases, reminiscent of the two-mixture model for liquid H(2)O. The modes of these variations, however, are qualitatively different between ACN-H(2)O and ACT-H(2)O. The former ACN is known to act as a hydrophobe and ACT as a hydrophile from our previous thermodynamic studies. To see the difference more clearly, we introduced and calculated the excess partial molar absorptivity of ACN and ACT, epsilon(E)(N) and epsilon(E)(T), respectively. The mole fraction dependences of epsilon(E)(N) and epsilon(E)(T) show qualitatively different behavior and are consistent with the detailed mixing schemes elucidated by our earlier differential thermodynamic studies. Furthermore, we found in the H(2)O-rich region that the effect of hydrophobic ACN is acted on the negative band at 5020 cm(-1), while that of hydrophilic ACT is on the positive high

  20. Effect of race/ethnicity on risk of complete and partial molar pregnancy after adjustment for age.

    PubMed

    Melamed, Alexander; Gockley, Allison A; Joseph, Naima T; Sun, Sue Yazaki; Clapp, Mark A; Goldstein, Donald P; Berkowitz, Ross S; Horowitz, Neil S

    2016-10-01

    To quantify the effect of race/ethnicity on risk of complete and partial molar pregnancy. We conducted a cross-sectional study including women who were followed for complete or partial mole and those who had a live singleton birth in a teaching hospital in the northeastern United States between 2000 and 2013. We calculated race/ethnicity-specific risk of complete and partial mole per 10,000 live births, and used logistic regression to estimate crude and age-adjusted relative risks (RR) of complete and partial mole. We identified 140 cases of complete mole, 115 cases of partial mole, and 105,942 live births. The risk of complete mole was 13 cases per 10,000 live births (95% confidence interval [CI] 11-16) and that of partial mole was 11 cases per 10,000 live births (95% CI 9-13). After age-adjustment, Asians were more likely to develop complete mole (RR 2.3 95% CI 1.4-3.8, p<0.001) but less likely to develop partial mole (RR 0.2; 95% CI 0.04-0.7, p=0.02) than whites. Blacks were significantly less likely than whites to develop partial mole (RR 0.4; 95% CI 0.2-0.8, p=0.01) but only marginally less likely to develop complete mole (RR 0.6; 95% CI 0.3-1.0, p=0.07). Hispanics were less likely than whites to develop complete mole (RR 0.4; 95% CI 0.2-0.7, p=0.002) and partial mole (RR 0.4; 95% CI 0.2-0.9, p=0.02). Race/ethnicity is a significant risk factor for both complete and partial molar pregnancy in the northeastern United States. Copyright © 2016 Elsevier Inc. All rights reserved.

  1. Does laterally rotated flap design influence the short-term periodontal status of second molars and postoperative discomfort after partially impacted third molar surgery?

    PubMed

    Korkmaz, Yavuz Tolga; Mollaoglu, Nur; Ozmeriç, Nurdan

    2015-06-01

    To assess the influence of the surgical removal of partially impacted third molars (3Ms) and compare the effects of a 3-cornered laterally rotated flap (LRF) with primary closure (flap 1) and an envelope flap with secondary closure (flap 2) on the short-term periodontal status of the adjacent second molars (2Ms). We also assessed the postoperative complications after removal of the partially impacted 3M. A split mouth, randomized clinical study was designed. The study sample included patients with bilateral partially impacted 3Ms. The primary predictor variable was the type of flap design (flaps 1 and 2). The primary outcome variable was periodontal status (gingival recession [GR], probing depth [PD], plaque index [PI], and gingival index) of the 2Ms measured preoperatively and 90 days postoperatively. The secondary outcome variables were postoperative complications, including pain, facial swelling, alveolitis, and local wound infection. The other variables included gender, position of the 3Ms, and surgical difficulty. We performed descriptive, comparative, correlation, and multivariate analyses. The sample included 28 patients aged 18 to 28 years. The GR, PD, and PI values with the flap 2 design were greater than those with the flap 1 design (P < .05). Facial swelling with the flap 1 design was significantly greater than with the flap 2 design on the second postoperative day (P < .05). The pain levels with the flap 1 design were significantly greater than those with the flap 2 design on the first and second postoperative days (P < .05). According to the multivariate regression analyses, flap design was closely related to the periodontal status of the 2Ms and postoperative discomfort. The results of the present clinical study have shown that the flap design in partially impacted 3M surgery considerably influences the early periodontal health of the 2Ms and postoperative discomfort. However, although the 3-cornered LRF design might cause more pain and swelling, it

  2. Analysis of the Velocity Distribution in Partially-Filled Circular Pipe Employing the Principle of Maximum Entropy.

    PubMed

    Jiang, Yulin; Li, Bin; Chen, Jie

    2016-01-01

    The flow velocity distribution in partially-filled circular pipe was investigated in this paper. The velocity profile is different from full-filled pipe flow, since the flow is driven by gravity, not by pressure. The research findings show that the position of maximum flow is below the water surface, and varies with the water depth. In the region of near tube wall, the fluid velocity is mainly influenced by the friction of the wall and the pipe bottom slope, and the variation of velocity is similar to full-filled pipe. But near the free water surface, the velocity distribution is mainly affected by the contractive tube wall and the secondary flow, and the variation of the velocity is relatively small. Literature retrieval results show relatively less research has been shown on the practical expression to describe the velocity distribution of partially-filled circular pipe. An expression of two-dimensional (2D) velocity distribution in partially-filled circular pipe flow was derived based on the principle of maximum entropy (POME). Different entropies were compared according to fluid knowledge, and non-extensive entropy was chosen. A new cumulative distribution function (CDF) of partially-filled circular pipe velocity in terms of flow depth was hypothesized. Combined with the CDF hypothesis, the 2D velocity distribution was derived, and the position of maximum velocity distribution was analyzed. The experimental results show that the estimated velocity values based on the principle of maximum Tsallis wavelet entropy are in good agreement with measured values.

  3. Separation and partial purification of acid phosphates of the enamel organ of rat molars.

    PubMed

    Anderson, T R; Toverud, S U; Yung, R C; Hanks, M H; Palik, J F

    1982-01-01

    At least two types of acid phosphatases with markedly different properties were separated from the enamel organ of rat molar tooth buds. One enzyme (A) bound weakly to the CM-cellulose column and was eluted with a combined linear salt and pH gradient; another enzyme (B) bound strongly to the column and was eluted with a second linear salt gradient at constant pH. Enzyme A was identified as a phosphomonoester hydrolase (3.1.3.2) similar to the lysosomal enzyme of soft tissues and the tartrate-sensitive enzyme of bone. Enzyme B did not hydrolyse aliphatic monophosphate ester substrates but, like enzyme A, it did split the aryl monophosphate ester substrate, para-nitrophenylphosphate, as well as the phosphate esters of casein and the acid anhydride substrates, ATP and inorganic pyrophosphate. This enzyme is similar to the low molecular weight tartrate-resistant acid phosphatases of bone and soft tissues.

  4. Analysis of the Velocity Distribution in Partially-Filled Circular Pipe Employing the Principle of Maximum Entropy

    PubMed Central

    2016-01-01

    The flow velocity distribution in partially-filled circular pipe was investigated in this paper. The velocity profile is different from full-filled pipe flow, since the flow is driven by gravity, not by pressure. The research findings show that the position of maximum flow is below the water surface, and varies with the water depth. In the region of near tube wall, the fluid velocity is mainly influenced by the friction of the wall and the pipe bottom slope, and the variation of velocity is similar to full-filled pipe. But near the free water surface, the velocity distribution is mainly affected by the contractive tube wall and the secondary flow, and the variation of the velocity is relatively small. Literature retrieval results show relatively less research has been shown on the practical expression to describe the velocity distribution of partially-filled circular pipe. An expression of two-dimensional (2D) velocity distribution in partially-filled circular pipe flow was derived based on the principle of maximum entropy (POME). Different entropies were compared according to fluid knowledge, and non-extensive entropy was chosen. A new cumulative distribution function (CDF) of partially-filled circular pipe velocity in terms of flow depth was hypothesized. Combined with the CDF hypothesis, the 2D velocity distribution was derived, and the position of maximum velocity distribution was analyzed. The experimental results show that the estimated velocity values based on the principle of maximum Tsallis wavelet entropy are in good agreement with measured values. PMID:26986064

  5. Cost-effectiveness of endodontic molar retreatment compared with fixed partial dentures and single-tooth implant alternatives.

    PubMed

    Kim, Sahng G; Solomon, Charles

    2011-03-01

    One of the most challenging situations in dentistry is a failed root canal treatment case. Should a failed root canal-treated tooth be retreated nonsurgically or surgically, or should the tooth be extracted and replaced with an implant-supported restoration or fixed partial denture? These four treatment alternatives were compared from the perspective of cost-effectiveness on the basis of the current best available evidence. The costs of the four major treatment modalities were calculated using the national fee averages from the 2009 American Dental Association survey of dental fees. The outcome data of all treatment modalities were retrieved from meta-analyses after electronic and manual searches were undertaken in the database from MEDLINE, Cochrane, ISI Web of Knowledge, and Scopus up to April 2010. The treatment strategy model was built and run with TreeAge decision analysis software (TreeAge Software, Inc, Williamstown, MA). Endodontic microsurgery was the most cost-effective approach followed by nonsurgical retreatment and crown, then extraction and fixed partial denture, and finally extraction and single implant-supported restoration. The cost-effectiveness analysis showed that endodontic microsurgery was the most cost-effective among all the treatment modalities for a failed endodontically treated first molar. A single implant-supported restoration, despite its high survival rate, was shown to be the least cost-effective treatment option based on current fees. Copyright © 2011 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

  6. Low-temperature molar heat capacities and entropies of MnO2 (pyrolusite), Mn3O4 (hausmanite), and Mn2O3 (bixbyite)

    USGS Publications Warehouse

    Robie, R.A.; Hemingway, B.S.

    1985-01-01

    Pyrolusite (MnO2), hausmanite (Mn3O4), and bixbyite (Mn2O3), are important ore minerals of manganese and accurate values for their thermodynamic properties are desirable to understand better the {p(O2), T} conditions of their formation. To provide accurate values for the entropies of these important manganese minerals, we have measured their heat capacities between approximately 5 and 380 K using a fully automatic adiabatically-shielded calorimeter. All three minerals are paramagnetic above 100 K and become antiferromagnetic or ferrimagnetic at lower temperatures. This transition is expressed by a sharp ??-type anomaly in Cpmo for each compound with Ne??el temperatures TN of (92.2??0.2), (43.1??0.2), and (79.45??0.05) K for MnO2, Mn3O4, and Mn2O3, respectively. In addition, at T ??? 308 K, Mn2O3 undergoes a crystallographic transition, from orthorhombic (at low temperatures) to cubic. A significant thermal effect is associated with this change. Hausmanite is ferrimagnetic below TN and in addition to the normal ??-shape of the heat-capacity maxima in MnO2 and Mn2O3, it has a second rounded maximum at 40.5 K. The origin of this subsidiary bump in the heat capacity is unknown but may be related to a similar "anomalous bump" in the curve of magnetization against temperature at about 39 K observed by Dwight and Menyuk.(1) At 298.15 K the standard molar entropies of MnO2, Mn3O4, and Mn2O3, are (52.75??0.07), (164.1??0.2), and (113.7??0.2) J??K-1??mol-1, respectively. Our value for Mn3O4 is greater than that adopted in the National Bureau of Standards tables(2) by 14 per cent. ?? 1985.

  7. Studies of Partial Molar Volumes of Some Narcotic-Analgesic Drugs in Aqueous-Alcoholic Mixtures at 25°C

    NASA Astrophysics Data System (ADS)

    Sharma, Poonam; Chauhan, S.; Syal, V. K.; Chauhan, M. S.

    2008-04-01

    Partial molar volumes of the drugs Parvon Spas, Parvon Forte, Tramacip, and Parvodex in aqueous mixtures of methanol (MeOH), ethanol (EtOH), and propan-1-ol (1-PrOH) have been determined. The data have been evaluated using the Masson equation. The parameters, apparent molar volumes {(φ_v)}, partial molar volumes {(φ_v0)}, and S v values (experimental slopes) have been interpreted in terms of solute solvent interactions. In addition, these studies have also been extended to determine the effect of these drugs on the solvation behavior of an electrolyte (sodium chloride), a surfactant (sodium dodecyl sulfate), and a non-electrolyte (sucrose). It can be inferred from these studies that all drug cations can be regarded as structure makers/promoters due to hydrophobic hydration. Furthermore, the results are correlated to understand the solution behavior of drugs in aqueous-alcoholic systems, as a function of the nature of the alcohol and solutes.

  8. Infinite dilution partial molar properties of aqueous solutions of nonelectrolytes. 1. Equations for partial molar volumes at infinite dilution and standard thermodynamic functions of hydration of volatile nonelectrolytes over wide ranges of conditions

    SciTech Connect

    Plyasunov, A.V.; O'Connell, J.P.; Wood, R.H.

    2000-02-01

    A semitheoretical expression for partial molar volumes at infinite dilution of aqueous nonelectrolyte solutes has been developed employing the collection of properties from fluctuation solution theory for use over wide ranges of temperature and pressure. The form of the solution expression was suggested by a comparison of solute/solvent and solvent/solvent direct correlations function integrals (DCFI). The selection of solvent density and compressibility as model variables provides a correct description in the critical region while second virial coefficients have been used to give a rigorous expression in the low density region. The formulation has been integrated to obtain analytic expressions for thermodynamic properties of hydration at supercritical temperatures. The equation is limited to solutes for which B{sub 12} (the second cross virial coefficient between water and a solute molecule) is known or can be estimated. Regression of the three remaining parameters gives good correlations of the available experimental data. A strategy for estimating these parameters allows prediction from readily available data.

  9. Entropy Evolution in the Magnetic Phases of Partially Frustrated CePdAl

    NASA Astrophysics Data System (ADS)

    Lucas, S.; Grube, K.; Huang, C.-L.; Sakai, A.; Wunderlich, S.; Green, E. L.; Wosnitza, J.; Fritsch, V.; Gegenwart, P.; Stockert, O.; v. Löhneysen, H.

    2017-03-01

    In the heavy-fermion metal CePdAl, long-range antiferromagnetic order coexists with geometric frustration of one-third of the Ce moments. At low temperatures, the Kondo effect tends to screen the frustrated moments. We use magnetic fields B to suppress the Kondo screening and study the magnetic phase diagram and the evolution of the entropy with B employing thermodynamic probes. We estimate the frustration by introducing a definition of the frustration parameter based on the enhanced entropy, a fundamental feature of frustrated systems. In the field range where the Kondo screening is suppressed, the liberated moments tend to maximize the magnetic entropy and strongly enhance the frustration. Based on our experiments, this field range may be a promising candidate to search for a quantum spin liquid.

  10. Randomized control trial comparing calcium hydroxide and mineral trioxide aggregate for partial pulpotomies in cariously exposed pulps of permanent molars.

    PubMed

    Chailertvanitkul, P; Paphangkorakit, J; Sooksantisakoonchai, N; Pumas, N; Pairojamornyoot, W; Leela-Apiradee, N; Abbott, P V

    2014-09-01

    To compare the treatment outcomes when calcium hydroxide and mineral trioxide aggregate are used for partial pulpotomy in cariously exposed young permanent molars in a randomized control trial. Eighty-four teeth in 80 volunteers (aged 7-10 years) with reversible pulpitis and carious pulp exposures were randomly divided into two groups. Exposed pulps were severed using high-speed round burs until fresh pulp was seen. Cavities were irrigated with 2.5% sodium hypochlorite, and the pulp exposures were photographed and measured. Dycal or ProRoot MTA was placed on the pulp. Vitremer was placed over the material until the remaining cavity was 2 mm deep; amalgam was then placed. Teeth were evaluated for clinical symptoms and radiographic periapical changes after 24 h, 3 months, 6 months, 1 year and 2 years. Mean survival times and incidence of extraction were calculated using exact binomial confidence intervals. The median survival time for both ProRoot MTA and Dycal groups was 24 months. Three teeth had unfavourable outcomes with the incidence rate of 0.20/100 tooth-months with ProRoot MTA (95% CI: 0.02-0.71) and 0.11/100 tooth-months with Dycal (95% CI: 0.001-0.60). The incidence of unfavourable outcomes was 0.05/100 (95% CI: 0.001-0.30) and 2.38/100 (95% CI: 0.29-8.34) tooth-months in teeth with small (<5 mm(2) ) and large (>5 mm(2) ) pulp exposure areas, respectively. Partial pulpotomy in teeth of young patients with reversible pulpitis, either using ProRoot MTA or Dycal, resulted in favourable treatment outcomes for up to 2 years. The incidence of unfavourable outcomes tended to be higher in teeth with pulp exposure areas larger than 5 mm(2) . © 2013 International Endodontic Journal. Published by John Wiley & Sons Ltd.

  11. Octanol-Water Partition Coefficient from 3D-RISM-KH Molecular Theory of Solvation with Partial Molar Volume Correction.

    PubMed

    Huang, WenJuan; Blinov, Nikolay; Kovalenko, Andriy

    2015-04-30

    The octanol-water partition coefficient is an important physical-chemical characteristic widely used to describe hydrophobic/hydrophilic properties of chemical compounds. The partition coefficient is related to the transfer free energy of a compound from water to octanol. Here, we introduce a new protocol for prediction of the partition coefficient based on the statistical-mechanical, 3D-RISM-KH molecular theory of solvation. It was shown recently that with the compound-solvent correlation functions obtained from the 3D-RISM-KH molecular theory of solvation, the free energy functional supplemented with the correction linearly related to the partial molar volume obtained from the Kirkwood-Buff/3D-RISM theory, also called the "universal correction" (UC), provides accurate prediction of the hydration free energy of small compounds, compared to explicit solvent molecular dynamics [ Palmer , D. S. ; J. Phys.: Condens. Matter 2010 , 22 , 492101 ]. Here we report that with the UC reparametrized accordingly this theory also provides an excellent agreement with the experimental data for the solvation free energy in nonpolar solvent (1-octanol) and so accurately predicts the octanol-water partition coefficient. The performance of the Kovalenko-Hirata (KH) and Gaussian fluctuation (GF) functionals of the solvation free energy, with and without UC, is tested on a large library of small compounds with diverse functional groups. The best agreement with the experimental data for octanol-water partition coefficients is obtained with the KH-UC solvation free energy functional.

  12. Proposition of group molar constants for sodium to calculate the partial solubility parameters of sodium salts using the van Krevelen group contribution method.

    PubMed

    Barra, J; Peña, M A; Bustamante, P

    2000-04-01

    The aim of this study is to propose, for the first time, a set of group molar constants for sodium to calculate the partial solubility parameters of sodium salts. The values were estimated using the few experimental partial solubility parameters of acid/sodium salt series available either from the literature (benzoic acid/Na, ibuprofen acid/Na, diclofenac Na) or determined in this work (salicylic acid/Na, p-aminobenzoic acid/Na, diclofenac), the group contribution method of van Krevelen to calculate the partial parameters of the acids, and three reasonable hypothesis. The experimental method used is a modification of the extended Hansen approach based on a regression analysis of the solubility mole fraction of the drug lnX(2) against models including three- or four-partial solubility parameters of a series of pure solvents ranging from non-polar (heptane) to highly polar (water). The modified method combined with the four-parameter model provided the best results for both acids and sodium derivatives. The replacement of the acidic proton by sodium increased the dipolar and basic partial solubility parameters, whereas the dispersion parameter remained unaltered, thus increasing the overall total solubility parameter of the salt. The proposed group molar constants of sodium are consistent with the experimental results as sodium has a relatively low London dispersion molar constant (identical to that of -OH), a very high Keesom dipolar molar constant (identical to that of -NO(2), two times larger than that of -OH), and a very high hydrogen bonding molar constant (identical to that of -OH). The proposed values are: F((Na)d)=270 (J cm(3))(1/2) mol(-1); F((Na)p)=1030 (J cm(3))(1/2) mol(-1); U((Na)h)=17000 J mol(-1). Like the constants for the other groups, the group molar constants proposed for sodium are certainly not the exact values. However, they are believed to be a fair approximation of the impact of sodium on the partial solubility parameters and, therefore, can

  13. Magnetic entropy change in amorphous and partially crystallized Fe-Mo-Cu-B alloy

    NASA Astrophysics Data System (ADS)

    Świerczek, Jan; Kupczyk, Anna

    2015-07-01

    Microstructure of the amorphous Fe76Mo10Cu1B13 ribbons in the as-quenched state and after the annealing at 723 K for 0.5 h is studied by transmission electron microscopy and Mössbauer spectroscopy. In the as-cast state α-Fe medium range ordered (MRO) regions are revealed and become the nuclei of crystalline grains. Nanograins 6 nm in the average diameter are observed in the sample subjected to the heat treatment. Mössbauer spectrum at 300 K of the annealed sample is decomposed into three subspectra ascribed to the amorphous paramagnetic and ferromagnetic phases and interface. At room temperature nanograins do not contribute to the spectra in the form of a single sextet due to magnetic relaxations. At 77 K the single sextet can be evidently introduced and its hyperfine parameters indicate the existence of the α-Fe(Mo) crystalline phase. The Curie point (TC) of the amorphous phase in the annealed samples shifts from 277 K in the as-cast state to 320 K after the annealing. The maximum of the magnetic entropy change (- ΔSM) in the as-quenched state occurs at temperature around TC of the amorphous phase and distinctly decreases after the annealing and shifts towards higher temperature but lower than TC of the amorphous remainder. - ΔSM in the superparamagnetic temperature range, i.e. above the Curie temperature of the amorphous phase obeys the phenomenological relation: - ΔSM = a(T)Bm / T + b B.m 2 / (T - Θ) 2 . The excellent | ΔSM | × Bm-2 = f(Bm-1) linear dependences for both, as-quenched and annealed samples are observed.

  14. Molecular analysis of 16S rRNA genes identifies potentially periodontal pathogenic bacteria and archaea in the plaque of partially erupted third molars.

    PubMed

    Mansfield, J M; Campbell, J H; Bhandari, A R; Jesionowski, A M; Vickerman, M M

    2012-07-01

    Small subunit rRNA sequencing and phylogenetic analysis were used to identify cultivable and uncultivable microorganisms present in the dental plaque of symptomatic and asymptomatic partially erupted third molars to determine the prevalence of putative periodontal pathogens in pericoronal sites. Template DNA prepared from subgingival plaque collected from partially erupted symptomatic and asymptomatic mandibular third molars and healthy incisors was used in polymerase chain reaction with broad-range oligonucleotide primers to amplify 16S rRNA bacterial and archaeal genes. Amplicons were cloned, sequenced, and compared with known nucleotide sequences in online databases to identify the microorganisms present. Two thousand three hundred two clones from the plaque of 12 patients carried bacterial sequences from 63 genera belonging to 11 phyla, including members of the uncultivable TM7, SR1, and Chloroflexi, and difficult-to-cultivate Synergistetes and Spirochaetes. Dialister invisus, Filifactor alocis, Fusobacterium nucleatum, Porphyromonas endodontalis, Prevotella denticola, Tannerella forsythia, and Treponema denticola, which have been associated with periodontal disease, were found in significantly greater abundance in pericoronal compared with incisor sites. Dialister invisus and F nucleatum were found in greater abundance in sites exhibiting clinical symptoms. The archaeal species, Methanobrevibacter oralis, which has been associated with severe periodontitis, was found in 3 symptomatic patients. These findings have provided new insights into the complex microbiota of pericoronitis. Several bacterial and archaeal species implicated in periodontal disease were recovered in greater incidence and abundance from the plaque of partially erupted third molars compared with incisors, supporting the hypothesis that the pericoronal region may provide a favored niche for periodontal pathogens in otherwise healthy mouths. Copyright © 2012 American Association of Oral and

  15. Twenty-four month clinical evaluation of fissure sealants on partially erupted permanent first molars: glass ionomer versus resin-based sealant.

    PubMed

    Antonson, Sibel A; Antonson, Donald E; Brener, Sandra; Crutchfield, Jude; Larumbe, Jose; Michaud, Christie; Yazici, A Rüya; Hardigan, Patrick C; Alempour, Samira; Evans, David; Ocanto, Rome

    2012-02-01

    Glass ionomer sealants are an alternative to resin-based sealants, especially for use in partially erupted permanent molars. The authors conducted a study to compare the retention, marginal staining and cariostatic properties of a glass ionomer sealant with those of a resin-based sealant during a 24-month period. We included in this study 39 patients aged 5 through 9 years who had bilateral partially erupted first permanent molars. One of us (S.B.) placed a resin-based sealant (Delton Plus FS+, Dentsply Professional, York, Pa.) (group D) on a partially erupted first molar in one quadrant of the maxilla or mandible and a glass ionomer sealant (GC Fuji Triage White, GC America, Alsip, Ill.) (group T) in the other quadrant. Two masked and calibrated investigators (S.A.A., J.C.) evaluated the sealants for retention, marginal staining and carious lesions at three, six, 12 and 24 months. The authors used a multinomial regression for statistical analysis (P < .05). The recall rate was 69.2 percent at 24 months. Two sealants from group D and three from group T were lost completely. Complete retention rates at 24 months were 40.7 and 44.4 percent for groups D and T, respectively. The authors found no statistically significant difference in retention rates between groups at each recall examination (P > .05). For marginal staining, sealants in the resin-based group exhibited statistically higher marginal staining than did sealants in the glass ionomer group (P < .05). Although the authors detected no caries in teeth in group T, teeth in group D in which the sealant was lost completely experienced demineralization. Resin-based and glass ionomer sealants exhibited similar retention rates at 24 months. However, marginal staining was lower in the glass ionomer group, and the authors found no caries in teeth in this group. Consequently, glass ionomer sealants may be a better choice when salivary contamination is expected. Sealing during tooth eruption presents a particular

  16. Entropy of adsorption of mixed surfactants from solutions onto the air/water interface

    USGS Publications Warehouse

    Chen, L.-W.; Chen, J.-H.; Zhou, N.-F.

    1995-01-01

    The partial molar entropy change for mixed surfactant molecules adsorbed from solution at the air/water interface has been investigated by surface thermodynamics based upon the experimental surface tension isotherms at various temperatures. Results for different surfactant mixtures of sodium dodecyl sulfate and sodium tetradecyl sulfate, decylpyridinium chloride and sodium alkylsulfonates have shown that the partial molar entropy changes for adsorption of the mixed surfactants were generally negative and decreased with increasing adsorption to a minimum near the maximum adsorption and then increased abruptly. The entropy decrease can be explained by the adsorption-orientation of surfactant molecules in the adsorbed monolayer and the abrupt entropy increase at the maximum adsorption is possible due to the strong repulsion between the adsorbed molecules.

  17. The impact of oxygen nonstoichiometry upon partial molar thermodynamic quantities in PrBaCo{sub 2}O{sub 5+δ}

    SciTech Connect

    Suntsov, A.Yu.; Leonidov, I.A.; Patrakeev, M.V.; Kozhevnikov, V.L.

    2014-05-01

    The coulometric titration data are utilized in order to calculate changes of oxygen partial entropy and enthalpy in PrBaCo{sub 2}O{sub 5+δ} with variations of oxygen content and temperature. The thermodynamic equilibrium of the cobaltite with the ambient gas phase is analyzed based on the interface of oxygen exchange and oxidation, and the intrinsic reaction of thermal excitation of Co{sup 3+} cations. The partial thermodynamic functions of the movable oxygen in PrBaCo{sub 2}O{sub 5+δ} are shown to be interrelated with the thermodynamic parameters of the defect formation reactions. The existence of a band gap of about 0.4 eV in the electronic spectrum of the cobaltite follows from a favorable comparison of the calculated and experimental dependencies of the partial thermodynamic functions of the movable oxygen. - Graphical abstract: Partial thermodynamic functions of movable oxygen in PrBaCo{sub 2}O{sub 5+δ}. - Highlights: • Thermodynamic functions of oxygen in PrBaCo{sub 2}O{sub 5+δ} are obtained from pO{sub 2}–T–δ diagram. • The defect model is developed to describe changes in thermodynamic functions. • Thermodynamic analysis gives evidence to a band gap in PrBaCo{sub 2}O{sub 5+δ}.

  18. Partial molar volumes of some alpha-amino acids in aqueous sodium acetate solutions at 308.15 K.

    PubMed

    Wang, J; Yan, Z; Zhuo, K; Lu, J

    1999-08-30

    The apparent molar volumes V(2,phi) have been determined for glycine, DL-alpha-alanine, DL-alpha-amino-n-butyric acid, DL-valine and DL-leucine in aqueous solutions of 0.5, 1.0, 1.5 and 2.0 mol kg(-1) sodium acetate by density measurements at 308.15 K. These data have been used to derive the infinite dilution apparent molar volumes V(0)(2,phi) for the amino acids in aqueous sodium acetate solutions and the standard volumes of transfer, Delta(t)V(0), of the amino acids from water to aqueous sodium acetate solutions. It has been observed that both V(0)(2,phi) and Delta(t)V(0) vary linearly with increasing number of carbon atoms in the alkyl chain of the amino acids. These linear correlations have been utilized to estimate the contributions of the charged end groups (NH(3)(+), COO(-)), CH(2) group and other alkyl chains of the amino acids to V(0)(2,phi) and Delta(t)V(0). The results show that V(0)(2,phi) values for (NH(3)(+), COO(-)) groups increase with sodium acetate concentration, and those for CH(2) are almost constant over the studied sodium acetate concentration range. The transfer volume increases and the hydration number of the amino acids decreases with increasing electrolyte concentrations. These facts indicate that strong interactions occur between the ions of sodium acetate and the charged centers of the amino acids. The volumetric interaction parameters of the amino acids with sodium acetate were calculated in water. The pair interaction parameters are found to be positive and decreased with increasing alkyl chain length of the amino acids, suggesting that sodium acetate has a stronger dehydration effect on amino acids which have longer hydrophobic alkyl chains. These phenomena are discussed by means of the co-sphere overlap model.

  19. Effect of race/ethnicity on clinical presentation and risk of gestational trophoblastic neoplasia in patients with complete and partial molar pregnancy at a tertiary care referral center.

    PubMed

    Gockley, Allison A; Joseph, Naima T; Melamed, Alexander; Sun, Sue Yazaki; Goodwin, Benjamin; Bernstein, Marilyn; Goldstein, Donald P; Berkowitz, Ross S; Horowitz, Neil S

    2016-09-01

    The reported incidence of molar pregnancy varies widely among different geographic locations. This variation has been attributed, at least in part, to racial/ethnic differences. While the incidence of molar pregnancies is decreasing, certain ethnic groups such as Hispanics, Asians, and American Indians continue to have an increased risk of developing gestational trophoblastic disease across the globe. We sought to describe the potential effect of ethnicity/race on the presentation and clinical course of complete mole and partial mole. All patients followed up for complete mole and partial mole at a single institution referral center from 1994 through 2013 were identified. Variables including age, race, gravidity, parity, gestational age, presenting signs/symptoms, serum human chorionic gonadotropin values, and development of gestational trophoblastic neoplasia were extracted from medical records and patient surveys. Patients with complete mole and partial mole were categorized into race/ethnicity groups defined as white, black, Asian, or Hispanic. Due to low numbers of non-white patients with partial mole in each non-white category, patients with partial mole were grouped as white or non-white. Continuous variables were compared using the Kruskal-Wallis test and binary variables were compared using the Fisher exact test. A total of 167 complete mole patients with known race/ethnicity status were included (57.48% white, 14.97% Asian, 14.37% black, 13.17% Hispanic). Hispanics presented at younger age (median 24.5 years) compared to whites (median 32.0 years, P = .04) and Asians (median 31.0 years, P = .03). Blacks had higher gravidity than whites (P < .001) and Hispanics (P = .05). There was no significant difference in presenting symptoms, gestational age at diagnosis, and preevacuation serum human chorionic gonadotropin level by race/ethnicity. Hispanics were significantly less likely than whites to develop gestational trophoblastic neoplasia (absolute risk

  20. Entropy of gaseous boron monobromide

    NASA Astrophysics Data System (ADS)

    Wang, Jian-Feng; Peng, Xiao-Long; Zhang, Lie-Hui; Wang, Chao-Wen; Jia, Chun-Sheng

    2017-10-01

    We present an explicit representation of molar entropy for gaseous boron monobromide in terms of experimental values of only three molecular constants. Fortunately, through comparison of theoretically calculated results and experimental data, we find that the molar entropy of gaseous boron monobromide can be well predicted by employing the improved Manning-Rosen oscillator to describe the internal vibration of boron monobromide molecule. The present approach provides also opportunities for theoretical predictions of molar entropy for other gases with no use of large amounts of experimental spectroscopy data.

  1. The Partial Molar Volume and Thermal Expansivity of Fe2O3 in Alkali Silicate Liquids: Evidence for the Average Coordination of Fe3+

    NASA Astrophysics Data System (ADS)

    Liu, Q.; Lange, R.

    2003-12-01

    Ferric iron is an important component in magmatic liquids, especially in those formed at subduction zones. Although it has long been known that Fe3+ occurs in four-, five- and six-fold coordination in crystalline compounds, only recently have all three Fe3+ coordination sites been confirmed in silicate glasses utilizing XANES spectroscopy at the Fe K-edge (Farges et al., 2003). Because the density of a magmatic liquid is largely determined by the geometrical packing of its network-forming cations (e.g., Si4+, Al3+, Ti4+, and Fe3+), the capacity of Fe3+ to undergo composition-induced coordination change affects the partial molar volume of the Fe2O3 component, which must be known to calculate how the ferric-ferrous ratio in magmatic liquids changes with pressure. Previous work has shown that the partial molar volume of Fe2O3 (VFe2O3) varies between calcic vs. sodic silicate melts (Mo et al., 1982; Dingwell and Brearley, 1988; Dingwell et al., 1988). The purpose of this study is to extend the data set in order to search for systematic variations in VFe2O3 with melt composition. High temperature (867-1534° C) density measurements were performed on eleven liquids in the Na2O-Fe2O3-FeO-SiO2 (NFS) system and five liquids in the K2O-Fe2O3-FeO-SiO2 (KFS) system using Pt double-bob Archimedean method. The ferric-ferrous ratio in the sodic and potassic liquids at each temperature of density measurement were calculated from the experimentally calibrated models of Lange and Carmichael (1989) and Tangeman et al. (2001) respectively. Compositions range (in mol%) from 4-18 Fe2O3, 0-3 FeO, 12-39 Na2O, 25-37 K2O, and 43-78 SiO2. Our density data are consistent with those of Dingwell et al. (1988) on similar sodic liquids. Our results indicate that for all five KFS liquids and for eight of eleven NFS liquids, the partial molar volume of the Fe2O3 component is a constant (41.57 ñ 0.14 cm3/mol) and exhibits zero thermal expansivity (similar to that for the SiO2 component). This value

  2. Inferring Weighted Directed Association Network from Multivariate Time Series with a Synthetic Method of Partial Symbolic Transfer Entropy Spectrum and Granger Causality

    PubMed Central

    Hu, Yanzhu; Ai, Xinbo

    2016-01-01

    Complex network methodology is very useful for complex system explorer. However, the relationships among variables in complex system are usually not clear. Therefore, inferring association networks among variables from their observed data has been a popular research topic. We propose a synthetic method, named small-shuffle partial symbolic transfer entropy spectrum (SSPSTES), for inferring association network from multivariate time series. The method synthesizes surrogate data, partial symbolic transfer entropy (PSTE) and Granger causality. A proper threshold selection is crucial for common correlation identification methods and it is not easy for users. The proposed method can not only identify the strong correlation without selecting a threshold but also has the ability of correlation quantification, direction identification and temporal relation identification. The method can be divided into three layers, i.e. data layer, model layer and network layer. In the model layer, the method identifies all the possible pair-wise correlation. In the network layer, we introduce a filter algorithm to remove the indirect weak correlation and retain strong correlation. Finally, we build a weighted adjacency matrix, the value of each entry representing the correlation level between pair-wise variables, and then get the weighted directed association network. Two numerical simulated data from linear system and nonlinear system are illustrated to show the steps and performance of the proposed approach. The ability of the proposed method is approved by an application finally. PMID:27832153

  3. Variation and decomposition of the partial molar volume of small gas molecules in different organic solvents derived from molecular dynamics simulations

    NASA Astrophysics Data System (ADS)

    Klähn, Marco; Martin, Alistair; Cheong, Daniel W.; Garland, Marc V.

    2013-12-01

    The partial molar volumes, bar V_i, of the gas solutes H2, CO, and CO2, solvated in acetone, methanol, heptane, and diethylether are determined computationally in the limit of infinite dilution and standard conditions. Solutions are described with molecular dynamics simulations in combination with the OPLS-aa force field for solvents and customized force field for solutes. bar V_i is determined with the direct method, while the composition of bar V_i is studied with Kirkwood-Buff integrals (KBIs). Subsequently, the amount of unoccupied space and size of pre-formed cavities in pure solvents is determined. Additionally, the shape of individual solvent cages is analyzed. Calculated bar V_i deviate only 3.4 cm3 mol-1 (7.1%) from experimental literature values. Experimental bar V_i variations across solutions are reproduced qualitatively and also quantitatively in most cases. The KBI analysis identifies differences in solute induced solvent reorganization in the immediate vicinity of H2 (<0.7 nm) and solvent reorganization up to the third solvation shell of CO and CO2 (<1.6 nm) as the origin of bar V_i variations. In all solutions, larger bar V_i are found in solvents that exhibit weak internal interactions, low cohesive energy density and large compressibility. Weak internal interactions facilitate solvent displacement by thermal solute movement, which enhances the size of solvent cages and thus bar V_i. Additionally, attractive electrostatic interactions of CO2 and the solvents, which do not depend on internal solvent interactions only, partially reversed the bar V_i trends observed in H2 and CO solutions where electrostatic interactions with the solvents are absent. More empty space and larger pre-formed cavities are found in solvents with weak internal interactions, however, no evidence is found that solutes in any considered solvent are accommodated in pre-formed cavities. Individual solvent cages are found to be elongated in the negative direction of solute

  4. Molar Pregnancy

    MedlinePlus

    ... Another treatment option is removal of the uterus (hysterectomy). Rarely, a cancerous form of GTD known as ... C usually takes about 15 to 30 minutes. Hysterectomy. If the molar tissue is extensive and there's ...

  5. Binding of an RNA aptamer and a partial peptide of a prion protein: crucial importance of water entropy in molecular recognition

    PubMed Central

    Hayashi, Tomohiko; Oshima, Hiraku; Mashima, Tsukasa; Nagata, Takashi; Katahira, Masato; Kinoshita, Masahiro

    2014-01-01

    It is a central issue to elucidate the new type of molecular recognition accompanied by a global structural change of a molecule upon binding to its targets. Here we investigate the driving force for the binding of R12 (a ribonucleic acid aptamer) and P16 (a partial peptide of a prion protein) during which P16 exhibits the global structural change. We calculate changes in thermodynamic quantities upon the R12–P16 binding using a statistical-mechanical approach combined with molecular models for water which is currently best suited to studies on hydration of biomolecules. The binding is driven by a water-entropy gain originating primarily from an increase in the total volume available to the translational displacement of water molecules in the system. The energy decrease due to the gain of R12–P16 attractive (van der Waals and electrostatic) interactions is almost canceled out by the energy increase related to the loss of R12–water and P16–water attractive interactions. We can explain the general experimental result that stacking of flat moieties, hydrogen bonding and molecular-shape and electrostatic complementarities are frequently observed in the complexes. It is argued that the water-entropy gain is largely influenced by the geometric characteristics (overall shapes, sizes and detailed polyatomic structures) of the biomolecules. PMID:24803670

  6. Physical entropy and the senses.

    PubMed

    Norwich, Kenneth H

    2005-01-01

    With reference to two specific modalities of sensation, the taste of saltiness of chloride salts, and the loudness of steady tones, it is shown that the laws of sensation (logarithmic and power laws) are expressions of the entropy per mole of the stimulus. That is, the laws of sensation are linear functions of molar entropy. In partial verification of this hypothesis, we are able to derive an approximate value for the gas constant, a fundamental physical constant, directly from psychophysical measurements. The significance of our observation lies in the linking of the phenomenon of "sensation" directly to a physical measure. It suggests that if the laws of physics are universal, the laws of sensation and perception are similarly universal. It also connects the sensation of a simple, steady physical signal with the molecular structure of the signal: the greater the number of microstates or complexions of the stimulus signal, the greater the magnitude of the sensation (saltiness or loudness). The hypothesis is currently tested on two sensory modalities.

  7. Cryogenic strength improvement by utilizing room-temperature deformation twinning in a partially recrystallized VCrMnFeCoNi high-entropy alloy

    PubMed Central

    Jo, Y. H.; Jung, S.; Choi, W. M.; Sohn, S. S.; Kim, H. S.; Lee, B. J.; Kim, N. J.; Lee, S.

    2017-01-01

    The excellent cryogenic tensile properties of the CrMnFeCoNi alloy are generally caused by deformation twinning, which is difficult to achieve at room temperature because of insufficient stress for twinning. Here, we induced twinning at room temperature to improve the cryogenic tensile properties of the CrMnFeCoNi alloy. Considering grain size effects on the critical stress for twinning, twins were readily formed in the coarse microstructure by cold rolling without grain refinement by hot rolling. These twins were retained by partial recrystallization and played an important role in improving strength, allowing yield strengths approaching 1 GPa. The persistent elongation up to 46% as well as the tensile strength of 1.3 GPa are attributed to additional twinning in both recrystallized and non-recrystallization regions. Our results demonstrate that non-recrystallized grains, which are generally avoided in conventional alloys because of their deleterious effect on ductility, can be useful in achieving high-strength high-entropy alloys. PMID:28604656

  8. Cryogenic strength improvement by utilizing room-temperature deformation twinning in a partially recrystallized VCrMnFeCoNi high-entropy alloy.

    PubMed

    Jo, Y H; Jung, S; Choi, W M; Sohn, S S; Kim, H S; Lee, B J; Kim, N J; Lee, S

    2017-06-12

    The excellent cryogenic tensile properties of the CrMnFeCoNi alloy are generally caused by deformation twinning, which is difficult to achieve at room temperature because of insufficient stress for twinning. Here, we induced twinning at room temperature to improve the cryogenic tensile properties of the CrMnFeCoNi alloy. Considering grain size effects on the critical stress for twinning, twins were readily formed in the coarse microstructure by cold rolling without grain refinement by hot rolling. These twins were retained by partial recrystallization and played an important role in improving strength, allowing yield strengths approaching 1 GPa. The persistent elongation up to 46% as well as the tensile strength of 1.3 GPa are attributed to additional twinning in both recrystallized and non-recrystallization regions. Our results demonstrate that non-recrystallized grains, which are generally avoided in conventional alloys because of their deleterious effect on ductility, can be useful in achieving high-strength high-entropy alloys.

  9. Partial phase diagrams of Pb-Mo-O system and the standard molar Gibbs energy of formation of PbMoO4 and Pb2MoO5

    NASA Astrophysics Data System (ADS)

    Aiswarya, P. M.; Ganesan, Rajesh; Gnanasekaran, T.

    2017-09-01

    Partial phase diagrams of Pb-Mo-O system have been established at 773 K and 998 K based on phase equilibration studies. Standard molar Gibbs energy of formation of ternary oxides PbMoO4 and Pb2MoO5 were determined by measuring the equilibrium oxygen partial pressures over relevant phase fields using emf cells and are given by the following expressions: ΔfGm° < PbMoO4 > ± 0.7(kJmol-1) = - 1030.1 + 0.3054(T /K) (T : 772to 1017K) ΔfGm° < Pb2 MoO5 > ± 0.8(kJmol-1) = - 1248.1 + 0.3872(T /K) (T : 741to 1021K)

  10. Progress in High-Entropy Alloys

    SciTech Connect

    Gao, Michael C

    2013-12-01

    Strictly speaking, high-entropy alloys (HEAs) refer to single-phase, solid-solution alloys with multiprincipal elements in an equal or a near-equal molar ratio whose configurational entropy is tremendously high. This special topic was organized to reflect the focus and diversity of HEA research topics in the community.

  11. Efficacy of orally administered prednisolone versus partial endodontic treatment on pain reduction in emergency care of acute irreversible pulpitis of mandibular molars: study protocol for a randomized controlled trial.

    PubMed

    Kérourédan, Olivia; Jallon, Léonard; Perez, Paul; Germain, Christine; Péli, Jean-François; Oriez, Dominique; Fricain, Jean-Christophe; Arrivé, Elise; Devillard, Raphaël

    2017-03-28

    Irreversible pulpitis is a highly painful inflammatory condition of the dental pulp which represents a common dental emergency. Recommended care is partial endodontic treatment. The dental literature reports major difficulties in achieving adequate analgesia to perform this emergency treatment, especially in the case of mandibular molars. In current practice, short-course, orally administered corticotherapy is used for the management of oral pain of inflammatory origin. The efficacy of intraosseous local steroid injections for irreversible pulpitis in mandibular molars has already been demonstrated but resulted in local comorbidities. Oral administration of short-course prednisolone is simple and safe but its efficacy to manage pain caused by irreversible pulpitis has not yet been demonstrated. This trial aims to evaluate the noninferiority of short-course, orally administered corticotherapy versus partial endodontic treatment for the emergency care of irreversible pulpitis in mandibular molars. This study is a noninferiority, open-label, randomized controlled clinical trial conducted at the Bordeaux University Hospital. One hundred and twenty subjects will be randomized in two 1:1 parallel arms: the intervention arm will receive one oral dose of prednisolone (1 mg/kg) during the emergency visit, followed by one morning dose each day for 3 days and the reference arm will receive partial endodontic treatment. Both groups will receive planned complete endodontic treatment 72 h after enrollment. The primary outcome is the proportion of patients with pain intensity below 5 on a Numeric Scale 24 h after the emergency visit. Secondary outcomes include comfort during care, the number of injected anesthetic cartridges when performing complete endodontic treatment, the number of antalgic drugs and the number of patients coming back for consultation after 72 h. This randomized trial will assess the ability of short-term corticotherapy to reduce pain in irreversible

  12. Effects of heat sink and source and entropy generation on MHD mixed convection of a Cu-water nanofluid in a lid-driven square porous enclosure with partial slip

    NASA Astrophysics Data System (ADS)

    Chamkha, A. J.; Rashad, A. M.; Mansour, M. A.; Armaghani, T.; Ghalambaz, M.

    2017-05-01

    In this work, the effects of the presence of a heat sink and a heat source and their lengths and locations and the entropy generation on MHD mixed convection flow and heat transfer in a porous enclosure filled with a Cu-water nanofluid in the presence of partial slip effect are investigated numerically. Both the lid driven vertical walls of the cavity are thermally insulated and are moving with constant and equal speeds in their own plane and the effect of partial slip is imposed on these walls. A segment of the bottom wall is considered as a heat source meanwhile a heat sink is placed on the upper wall of cavity. There are heated and cold parts placed on the bottom and upper walls, respectively, while the remaining parts are thermally insulated. Entropy generation and local heat transfer according to different values of the governing parameters are presented in detail. It is found that the addition of nanoparticles decreases the convective heat transfer inside the porous cavity at all ranges of the heat sink and source lengths. The results for the effects of the magnetic field show that the average Nusselt number decreases considerably upon the enhancement of the Hartmann number. Also, adding nanoparticles to a pure fluid leads to increasing the entropy generation for all values of D for λl=-λr = 1 .

  13. Melt densities in the CaO-FeO-Fe 2O 3-SiO 2 system and the compositional dependence of the partial molar volume of ferric iron in silicate melts

    NASA Astrophysics Data System (ADS)

    Dingwell, Donald B.; Brearley, Mark

    1988-12-01

    The densities of 10 melts in the CaO-FeO-Fe 2O 3-SiO 2 system were determined in equilibrium with air, in the temperature range of 1200 to 1550°C, using the double-bob Archimedean technique. Melt compositions range from 6 to 58 wt% SiO 2, 14 to 76 wt% Fe 2O 3 and 10 to 46 wt% CaO. The ferric-ferrous ratios of glasses drop-quenched from loop fusion equilibration experiments were determined by 57Fe Mössbauer spectroscopy. Melt densities range from 2.689 to 3.618 gm/cm 3 with a mean standard deviation from replicate experiments of 0.15%. Least-squares regressions of molar volume versus molar composition have been performed and the root mean squared deviation shows that a linear combination of partial molar volumes for the oxide components (CaO, FeO, Fe 2O 3 and SiO 2) cannot describe the data set within experimental error. Instead, the inclusion of excess terms in CaFe 3+ and CaSi (product terms using the oxides) is required to yield a fit that describes the experimental data within error. The nonlinear compositional-dependence of the molar volumes of melts in this system can be explained by structural considerations of the roles of Ca and Fe 3+. The volume behavior of melts in this system is significantly different from that in the Na 2O-FeO-Fe 2O 3-SiO 2 system, consistent with the proposal that a proportion of Fe 3+ in melts in the CaO-FeO-Fe 2O 3-SiO 2 system is not tetrahedrally-coordinated by oxygen, which is supported by differences in 57Fe Mössbauer spectra of glasses. Specifically, this study confirms that the 57Fe Mössbauer spectra exhibit an area asymmetry and higher values of isomer shift of the ferric doublet that vary systematically with composition and temperature (this study; Dingwell and Virgo, 1987, 1988). These observations are consistent with a number of other lines of evidence ( e.g., homogeneous redox equilibria, Dickenson and Hess, 1986; viscosity, Dingwell and Virgo, 1987,1988). Two species of ferric iron, varying in proportions with

  14. Magnetic entropy change and magnetic properties of LaFe11.5Si1.5 after controlling the Curie temperature by partial substitution of Mn and hydrogenation

    NASA Astrophysics Data System (ADS)

    Bin, Fu; Jie, Han

    2016-02-01

    Magnetic properties and magnetic entropy changes of La(Fe1-xMnx)11.5Si1.5Hy compounds are investigated. Their Curie temperatures are adjusted to room temperature by partial Mn substitution for Fe and hydrogen absorption in 1-atm (1 atm = 1.01325 × 105 Pa) hydrogen gas. Under a field change from 0 T to 2 T, the maximum magnetic entropy change for La(Fe0.99Mn0.01)11.5Si1.5H1.61 is -11.5 J/kg. The suitable Curie temperature and large value of ΔSm make it an attractive potential candidate for the room temperature magnetic refrigeration application. Projct supported by the Science and Technology Development Fund of Higher Education of Tianjin, China (Grant No. 20130301) and the Tianjin Research Program of Application Foundation and Advanced Technology, China (Grant No. 14JCQNJC4000).

  15. A Molar Pregnancy within the Fallopian Tube

    PubMed Central

    Dawson, Charlotte; Nascu, Patricia; Rouse, Tyler

    2016-01-01

    Background. Discussion of the incidence of molar pregnancy and ectopic pregnancy. Role of salpingostomy and special considerations for postoperative care. Case. The patient is a 29-year-old G7P4 who presented with vaginal bleeding in the first trimester and was initially thought to have a spontaneous abortion. Ultrasound was performed due to ongoing symptoms and an adnexal mass was noted. She underwent uncomplicated salpingostomy and was later found to have a partial molar ectopic pregnancy. Conclusion. This case illustrates the rare occurrence of a molar ectopic pregnancy. There was no indication of molar pregnancy preoperatively and this case highlights the importance of submitting and reviewing pathological specimens. PMID:28044117

  16. Pathoses associated with mandibular third molars subjected to removal.

    PubMed

    Knutsson, K; Brehmer, B; Lysell, L; Rohlin, M

    1996-07-01

    To measure the prevalence of disease of mandibular third molars referred for removal and to estimate the risk for development of pathoses for two cues. A prospective cohort study on molars subjected to removal was performed. The prevalence of different diseases and the patient's age, angular position, and degree of impaction of the molars were registered. Odds ratio for molars with different positions and impaction states were estimated. Pericoronitis was found in 64% of cases, caries in the third molar in 31%, periodontitis in association with 8%, caries in the second molar in 5%, and root resorption of the second molar with 1% of the molars with pathoses. Odds ratio was highest for distoangular molars (5.8) and for molars partially covered by soft tissue (6.7). The odds ratio is about 22 and 34 times higher for molars partially covered by soft tissue than for molars completely covered by soft or bone tissue. For distoangular molars the odds ratio is 5 to 12 times higher than for molars in other positions.

  17. First permanent molars with molar incisor hypomineralisation.

    PubMed

    Fitzpatrick, Laura; O'Connell, Anne

    2007-01-01

    Molar incisor hypomineralisation (MIH) is a common enamel defect presenting in the first permanent molars (FPM) and permanent incisors. This article presents the clinical findings and management considerations for the FPM with MIH to the general practitioner. The various treatment options are described with emphasis placed on early diagnosis as the most important prognostic factor.

  18. Dissipation, interaction, and relative entropy.

    PubMed

    Gaveau, B; Granger, L; Moreau, M; Schulman, L S

    2014-03-01

    Many thermodynamic relations involve inequalities, with equality if a process does not involve dissipation. In this article we provide equalities in which the dissipative contribution is shown to involve the relative entropy (also called the Kullback-Leibler divergence). The processes considered are general time evolutions in both classical and quantum mechanics, and the initial state is sometimes thermal, sometimes partially so. As an application, the relative entropy is related to transport coefficients.

  19. Low-temperature heat capacity and entropy of chalcopyrite (CuFeS2): estimates of the standard molar enthalpy and Gibbs free energy of formation of chalcopyrite and bornite (Cu5FeS4)

    USGS Publications Warehouse

    Robie, R.A.; Wiggins, L.B.; Barton, P.B.; Hemingway, B.S.

    1985-01-01

    The heat capacity of CuFeS2 (chalcopyrite) was measured between 6.3 and 303.5 K. At 298.15 K, Cp,mo and Smo(T) are (95.67??0.14) J??K-1??mol-1 and (124.9??0.2) J??K-1??mol-1, respectively. From a consideration of the results of two sets of equilibrium measurements we conclude that ??fHmo(CuFeS2, cr, 298.15 K) = -(193.6??1.6) kJ??mol-1 and that the recent bomb-calorimetric determination by Johnson and Steele (J. Chem. Thermodynamics 1981, 13, 991) is in error. The standard molar Gibbs free energy of formation of bornite (Cu5FeS4) is -(444.9??2.1) kJ??mol-1 at 748 K. ?? 1985.

  20. Density and sound speed measurements on model basalt (An-Di-Hd) liquids at one bar: New constraints on the partial molar volume and compressibility of the FeO component

    NASA Astrophysics Data System (ADS)

    Guo, Xuan; Lange, Rebecca A.; Ai, Yuhui

    2014-02-01

    Density and sound speed measurements were obtained over a wide range of temperature for three model basalt liquids in the An-Di-Hd (CaAl2Si2O8-CaMgSi2O6-CaFeSi2O6) system. High-temperature (1585-1838 K) double-bob density measurements were combined with low-temperature (943-930 K) measurements at the limiting fictive temperature for each sample to provide liquid volume data over a temperature interval of ∼900 K. In addition, relaxed sound speeds were obtained with a frequency sweep acoustic interferometer from 1665-1876 K. An ideal mixing model for molar volume, thermal expansivity, and isothermal compressibility recovers the new data from this study and leads to the following fitted values (±2σ) at 1723 K for VbarFeO (12.86±0.32 cm/mol), ∂VbarFeO/∂T((3.69±1.16)×10-3 cm/mol-K) and βbarT,FeO((4.72±0.46)×10-2 GPa). These volumetric properties for the FeO component are estimated to reflect Fe2+ in an average coordination of 5.7 (±0.2), based on the relationship between VbarFeO and Fe2+ coordination derived by a comparison to mineral molar volumes (Guo et al., 2013). Application of these volumetric data to a calculation of the pressure dependence of the Fe-Mg exchange reaction between orthopyroxene and basaltic liquid results in a small decrease in Fe-MgKD with pressure. In contrast, partial melting experiments of peridotite show a small increase in Fe-MgKD(opx-liq) with pressure (e.g., Walter, 1998). This difference in the pressure dependence is proposed to reflect the role of alkalis in reducing the average coordination number of Fe2+ toward five compared to the alkali-free model basalt compositions in this study, thus changing the volume and compressibility of the FeO liquid component. The results from this study may be most appropriately applied to lunar basalts, which are impoverished in alkalis.

  1. [Hyperthyroidism in molar pregnancy].

    PubMed

    Boufettal, H; Mahdoui, S; Noun, M; Hermas, S; Samouh, N

    2014-03-01

    Hyperthyroidism is a rare complication of molar pregnancy. We report a 39-year-old woman who presented a thyrotoxic syndrome accompanying a molar pregnancy. Serum thyroid hormones were elevated and returned to normal level after uterine evacuation of a molar pregnancy. The authors detail the role of thyroid stimulating property of human gonadotropin chorionic hormone and its structural changes during the gestational trophoblastic diseases. These changes give the latter the thyroid stimulating properties and signs of hyperthyroidism. Molar pregnancy may be a cause of hyperthyroidism. The diagnosis of molar pregnancy should be a mention to thyrotoxicosique syndrome in a woman of childbearing age. Copyright © 2013. Published by Elsevier SAS.

  2. Deciduous molar hypomineralization and molar incisor hypomineralization.

    PubMed

    Elfrink, M E C; ten Cate, J M; Jaddoe, V W V; Hofman, A; Moll, H A; Veerkamp, J S J

    2012-06-01

    This study was embedded in the Generation R Study, a population-based prospective cohort study from fetal life until young adulthood. This study focused on the relationship between Deciduous Molar Hypomineralization (DMH) and Molar Incisor Hypomineralization (MIH). First permanent molars develop during a period similar to that of second primary molars, with possible comparable risk factors for hypomineralization. Children with DMH have a greater risk of developing MIH. Clinical photographs of clean, moist teeth were taken with an intra-oral camera in 6,161 children (49.8% girls; mean age 74.3 mos, SD ± 5.8). First permanent molars and second primary molars were scored with respect to DMH or MIH. The prevalence of DMH and MIH was 9.0% and 8.7% at child level, and 4.0% and 5.4% at tooth level. The Odds Ratio for MIH based on DMH was 4.4 (95% CI, 3.1-6.4). The relationship between the occurrence of DMH and MIH suggests a shared cause and indicates that, clinically, DMH can be used as a predictor for MIH.

  3. Absolute entropy and free energy of fluids using the hypothetical scanning method. II. Transition probabilities from canonical Monte Carlo simulations of partial systems

    NASA Astrophysics Data System (ADS)

    White, Ronald P.; Meirovitch, Hagai

    2003-12-01

    A variant of the hypothetical scanning (HS) method for calculating the absolute entropy and free energy of fluids is developed, as applied to systems of Lennard-Jones atoms (liquid argon). As in the preceding paper (Paper I), a probability Pi approximating the Boltzmann probability of system configuration i, is calculated with a reconstruction procedure based on adding the atoms gradually to an initially empty volume, where they are placed in their positions at i; in this process the volume is divided into cubic cells, which are visited layer-by-layer, line-by-line. At each step a transition probability (TP) is calculated and the product of all the TPs leads to Pi. At step k, k-1 cells have already been treated, where among them Nk are occupied by an atom. A canonical metropolis Monte Carlo (MC) simulation is carried out over a portion of the still unvisited (future) volume thus providing an approximate representation of the N-Nk as yet untreated (future) atoms. The TP of target cell k is determined from the number of visits of future atoms to this cell during the simulation. This MC version of HS, called HSMC, is based on a relatively small number of efficiency parameters; their number does not grow and their values are not changed as the number of the treated future atoms is increased (i.e., as the approximation improves); therefore, implementing HSMC for a relatively large number of future atoms (up to 40 in this study) is straightforward. Indeed, excellent results have been obtained for the free energy and the entropy.

  4. Entropy, materials, and posterity

    USGS Publications Warehouse

    Cloud, P.

    1977-01-01

    Materials and energy are the interdependent feedstocks of economic systems, and thermodynamics is their moderator. It costs energy to transform the dispersed minerals of Earth's crust into ordered materials and structures. And it costs materials to collect and focus the energy to perform work - be it from solar, fossil fuel, nuclear, or other sources. The greater the dispersal of minerals sought, the more energy is required to collect them into ordered states. But available energy can be used once only. And the ordered materials of industrial economies become disordered with time. They may be partially reordered and recycled, but only at further costs in energy. Available energy everywhere degrades to bound states and order to disorder - for though entropy may be juggled it always increases. Yet industry is utterly dependent on low entropy states of matter and energy, while decreasing grades of ore require ever higher inputs of energy to convert them to metals, with ever increasing growth both of entropy and environmental hazard. Except as we may prize a thing for its intrinsic qualities - beauty, leisure, love, or gold - low-entropy is the only thing of real value. It is worth whatever the market will bear, and it becomes more valuable as entropy increases. It would be foolish of suppliers to sell it more cheaply or in larger amounts than their own enjoyment of life requires, whatever form it may take. For this reason, and because of physical constraints on the availability of all low-entropy states, the recent energy crises is only the first of a sequence of crises to be expected in energy and materials as long as current trends continue. The apportioning of low-entropy states in a modern industrial society is achieved more or less according to the theory of competitive markets. But the rational powers of this theory suffer as the world grows increasingly polarized into rich, over-industrialized nations with diminishing resource bases and poor, supplier nations

  5. Entropy of Mixing of Distinguishable Particles

    ERIC Educational Resources Information Center

    Kozliak, Evguenii I.

    2014-01-01

    The molar entropy of mixing yields values that depend only on the number of mixing components rather than on their chemical nature. To explain this phenomenon using the logic of chemistry, this article considers mixing of distinguishable particles, thus complementing the well-known approach developed for nondistinguishable particles, for example,…

  6. Entropy of Mixing of Distinguishable Particles

    ERIC Educational Resources Information Center

    Kozliak, Evguenii I.

    2014-01-01

    The molar entropy of mixing yields values that depend only on the number of mixing components rather than on their chemical nature. To explain this phenomenon using the logic of chemistry, this article considers mixing of distinguishable particles, thus complementing the well-known approach developed for nondistinguishable particles, for example,…

  7. Current management of molar pregnancy.

    PubMed

    Hancock, Barry W; Tidy, John A

    2002-05-01

    Molar pregnancy remains an uncommon and still not fully understood disorder. The clinical presentation has changed over recent decades. In developed countries complete moles are now usually diagnosed early (on clinical and/or ultrasound scan criteria) so that the more severe clinical presentations are much less commonly seen. The important differences between complete and partial moles and their risk factors are now well recognized. Common protocols for managing persistent gestational trophoblastic disease are being derived, and molecular genetic studies are advancing our understanding of molar pregnancy and its sequelae. Cure rates approaching 100% should now be the rule rather than the exception. There is a strong case for formal registration and monitoring of all cases through specialist centers.

  8. Transfer Partial Molar Isentropic Compressibilities of ( l-Alanine/ l-Glutamine/Glycylglycine) from Water to 0.512 {mol} \\cdot {kg}^{-1} Aqueous {KNO}3/0.512 {mol} \\cdot {kg}^{-1} Aqueous {K}2{SO}4 Solutions Between 298.15 K and 323.15 K

    NASA Astrophysics Data System (ADS)

    Riyazuddeen; Gazal, Umaima

    2013-03-01

    Speeds of sound of ( l-alanine/ l-glutamine/glycylglycine + 0.512 {mol}\\cdot {kg}^{-1} aqueous {KNO}3/0.512 {mol}\\cdot {kg}^{-1} aqueous {K}2{SO}4) systems have been measured for several molal concentrations of amino acid/peptide at different temperatures: T = (298.15 to 323.15) K. Using the speed-of-sound and density data, the parameters, partial molar isentropic compressibilities φ _{kappa }0 and transfer partial molar isentropic compressibilities Δ _{tr} φ _{kappa }0, have been computed. The trends of variation of φ _{kappa }0 and Δ _{tr} φ _{kappa }0 with changes in molal concentration of the solute and temperature have been discussed in terms of zwitterion-ion, zwitterion-water dipole, ion-water dipole, and ion-ion interactions operative in the systems.

  9. Molar incisor hypomineralization.

    PubMed

    Mahoney, Erin

    2012-04-01

    Molar Incisor Hypomineralization (MIH) is a common condition in New Zealand children and children around the world and can result in a significant defect in first permanent molars. This condition inevitably leads to a large amount of dental treatment for young children and may even result in the removal of their first permanent molars. This lecture will outline the understanding of the physical properties of these teeth and provide an evidence based review of the treatment options for affected teeth.

  10. Upper entropy axioms and lower entropy axioms

    SciTech Connect

    Guo, Jin-Li Suo, Qi

    2015-04-15

    The paper suggests the concepts of an upper entropy and a lower entropy. We propose a new axiomatic definition, namely, upper entropy axioms, inspired by axioms of metric spaces, and also formulate lower entropy axioms. We also develop weak upper entropy axioms and weak lower entropy axioms. Their conditions are weaker than those of Shannon–Khinchin axioms and Tsallis axioms, while these conditions are stronger than those of the axiomatics based on the first three Shannon–Khinchin axioms. The subadditivity and strong subadditivity of entropy are obtained in the new axiomatics. Tsallis statistics is a special case of satisfying our axioms. Moreover, different forms of information measures, such as Shannon entropy, Daroczy entropy, Tsallis entropy and other entropies, can be unified under the same axiomatics.

  11. ["Molar-incisor hypomineralization"].

    PubMed

    Kellerhoff, Nadja-Marina; Lussi, Adrian

    2004-01-01

    Hypocalcification of the enamel is the most common developmental disorder observed in teeth. The prevalence of this kind of hypomineralisation is about 10-19%. These molars are often referred to as cheese molars, because the lesions clinically resemble cheese in color and consistency. Other descriptions are: idiopathic enamel hypomineralisation in the permanent first molars, idiopathic enamel opacities in the permanent first molars, non fluoride enamel hypomineralisation in the permanent first molars, non-endemic mottling of enamel in the permanent first molars. Molar-Incisor Hypomineralisation is today the proposed expression for this disease. Occlusal surfaces of the first permanent molar are most commonly affected. The lesions are more frequent in the upper jaw than in the lower jaw. The incisors are affected to a lesser degree than the molars. Several aetiological factors can cause these defects. Some studies show a relation between intake of dioxins via mother's milk after prolonged breast feeding and developmental defects of the child's teeth. Because the ameloblasts are very sensitive to oxygen supply, complications involving oxygen shortages during birth or respiratory diseases such as asthma or bronchitis and pneumonia are discussed as further aetiological factors. Renal insufficiency, hypoparothyroidism, diarrhoea, malabsorption and malnutrition and high-fever diseases can be other reasons for the occurrence of these defects. Defective enamel can be a locus of lowered resistance for caries. Histologically there are areas of porosity of varying degrees. The affected teeth can be very sensitive to air, cold, warm and mechanical stimuli. Toothbrushing may create toothache in these teeth. We therefore suggest that these patients receive intensified prevention with fluoride varnish, a fissure sealing, GIZ, composits, stainless steel crowns or implants. In some cases an interdisciplinary approach with an orthodontist can result in the extraction of the molars

  12. Prevalence of missing and impacted third molars in adults aged 25 years and above

    PubMed Central

    Jung, Yun-Hoa

    2013-01-01

    Purpose The purpose of this study was to determine the prevalence of missing and impacted third molars in people aged 25 years and above. Materials and Methods The study sample of 3,799 patients was chosen randomly from patients who visited Pusan National University Dental Hospital and had panoramic radiographs taken. The data collected included presence and impaction state, angulation, and depth of impaction of third molars, and radiographically detected lesions of third molars and adjacent second molars. Results A greater percentage of men than women retained at least one third molar. The incidence of third molars decreased with increasing age. The incidence of partially impacted third molars greatly declined after the age of 30. Vertically impacted maxillary third molars and horizontally impacted mandibular third molars were most frequent in all age groups. Among the maxillary third molars, those impacted below the cervical line of the second molar were most frequent in all age groups, and among the mandibular third molars, deeply impacted third molars were most frequent in those aged over 40. Dental caries was the most common radiographic lesion of the third molars. Mesioangularly impacted third molars showed radiographic lesions in 13 (9.5%) adjacent maxillary second molars and 117 (27.4%) mandibular second molars. Conclusion The number of remaining third molars decreased and the percentage of Class C depth increased with age. Caries was the most frequent lesion in third molars. Partially impacted mesioangular third molars showed a high incidence of caries or periodontal bone loss of the adjacent second molar. Regular oral examination will be essential to keep asymptomatic third molars in good health. PMID:24380060

  13. Correct Expressions of Enthalpy of Mixing and Excess Entropy from MIVM and Their Simplified Forms

    NASA Astrophysics Data System (ADS)

    Tao, Dong-Ping

    2016-02-01

    In this work, the author pointed out that empirically to compare the molecular interaction volume model (MIVM) with thermodynamic definition of excess Gibbs energy would result in the incorrect expressions of enthalpy of mixing and excess entropy. The correct expressions of molar and partial molar enthalpies of mixing and excess entropies from the MIVM are consistent thermodynamically and are suggested for replacing their past incorrect ones. The simplification of Z i = Z = 10 is verified to be feasible by the average errors of fitting in the binary liquid alloys M-P (M = Cr, Fe, and Mn) and of predicting in the ternary liquid alloys Fe-Cr-P and Fe-Mn-P by using two coordination numbers of phosphorus Z P = 3.04 and Z P = 8.96. Further, their simplified forms are proposed for predicting easily thermodynamic properties of a multicomponent liquid system and are preliminarily tested to be coordinated mutually in the binary liquid alloys Au-Cu, Cd-Zn, Ca-Zn, and Ni-Pb.

  14. Accuracy of the Third Molar Eruption Predictor in predicting eruption.

    PubMed

    Ventä, I; Schou, S

    2001-06-01

    To evaluate the possibility of applying the Third Molar Eruption Predictor to all panoramic radiographs. Panoramic radiographs were retrospectively analyzed from a 4-year follow-up study of third molars carried out at the University of Copenhagen, Denmark. The radiographs, taken at a mean age of 20.6 years, included 45 unerupted or partially erupted mandibular third molars in 28 subjects. Because the device was calibrated both with simple proportions and by use of the methods of Bayes' Decision Theory, the separation point of the device was therefore adjusted at 12 mm from the distal surface of the second molar. The predictions of future eruption or impaction made with the calibrated device and the actual clinical outcome 4 years later were in conformity for 80% of the mandibular third molars. The Third Molar Eruption Predictor may be applied to all panoramic radiographs, but it seems to require calibration before use.

  15. Third molar infections.

    PubMed

    Gutiérrez-Pérez, José Luis

    2004-01-01

    Pericoronitis is an infectious disease often associated with the eruption of a third molar. It can be either acute (serous and suppurative) or chronic. Pain is usually the predominant symptom in acute stages, whereas chronic forms of the disease may display very few symptoms. Both present exudate. The infection is multimicrobial, predominantly caused strictly by betalactamase-producing anaerobeic microorganisms. Treatment measures are symptomatic, antimicrobial and surgical. Antimicrobial treatment is indicated for preoperative prophylaxis when there is a high risk of postoperative infection and, during the acute stages of suppurative pericoronitis when surgery must be postponed. First-line treatment in this case consists of amoxicillin with associated clavulanic acid. Although surgical treatment of pericoronitis presenting at the third molar is indicated as a Grade C recommendation for extraction, it is the most common indication for extraction of a retained third molar, owing to the improved quality of life it can offer the patient.

  16. Entropy power inequalities for qudits

    NASA Astrophysics Data System (ADS)

    Audenaert, Koenraad; Datta, Nilanjana; Ozols, Maris

    2016-05-01

    Shannon's entropy power inequality (EPI) can be viewed as a statement of concavity of an entropic function of a continuous random variable under a scaled addition rule: f ( √{ a } X + √{ 1 - a } Y ) ≥ a f ( X ) + ( 1 - a ) f ( Y ) ∀ a ∈ [ 0 , 1 ] . Here, X and Y are continuous random variables and the function f is either the differential entropy or the entropy power. König and Smith [IEEE Trans. Inf. Theory 60(3), 1536-1548 (2014)] and De Palma, Mari, and Giovannetti [Nat. Photonics 8(12), 958-964 (2014)] obtained quantum analogues of these inequalities for continuous-variable quantum systems, where X and Y are replaced by bosonic fields and the addition rule is the action of a beam splitter with transmissivity a on those fields. In this paper, we similarly establish a class of EPI analogues for d-level quantum systems (i.e., qudits). The underlying addition rule for which these inequalities hold is given by a quantum channel that depends on the parameter a ∈ [0, 1] and acts like a finite-dimensional analogue of a beam splitter with transmissivity a, converting a two-qudit product state into a single qudit state. We refer to this channel as a partial swap channel because of the particular way its output interpolates between the states of the two qudits in the input as a is changed from zero to one. We obtain analogues of Shannon's EPI, not only for the von Neumann entropy and the entropy power for the output of such channels, but also for a much larger class of functions. This class includes the Rényi entropies and the subentropy. We also prove a qudit analogue of the entropy photon number inequality (EPnI). Finally, for the subclass of partial swap channels for which one of the qudit states in the input is fixed, our EPIs and EPnI yield lower bounds on the minimum output entropy and upper bounds on the Holevo capacity.

  17. Endodontic treatment of molars

    PubMed Central

    Habl, Claudia; Bodenwinkler, Andrea; Stürzlinger, Heidi

    2006-01-01

    Objective Commissioned by the German Institute of Medical Documentation and Information (DIMDI) the Austrian Health Institute (ÖBIG) prepared a HTA report on the long-term effectiveness of endodontic treatment (root canal treatment, RCT) of molars. The focus is to examine factors influencing the outcome of endodontic treatment and showing their impact on long-term results. Additionally, economic aspects of root canal treatment in Germany are discussed. Methodology By performing a systematic literature search in 29 databases (e.g. MEDLINE), the Cochrane Library and by hand searching two peer-reviewed endodontic journals the authors could identify 750 relevant articles, of which finally 18 qualified for assessment. Results The findings show that the most relevant factor influencing the long-term outcome of endodontic treatment is the preoperative status of a tooth. The lowest success rates are reported for molars with a preoperative devital or necrotic pulp and persisting periapical lesions (so called periapical disease). Discussion Even if there is no positive selection of patients and the RCT is performed by a normal dentist rather than an endodontist - a fact which is very common - long-term success rates of more then 90% are possible. The overall success rates for endodontic treatment of molars therefore seem to be similar to those of other tooth-types. Conclusions Especially primary, conventional (i.e. non-surgical) root canal treatment is an effective and efficient therapy for endodontically ill molars, especially if no large periapical lesion persists. Nonetheless, a long term successful endodontic therapy requires a thorough assessment of the pre-operative status of the molar and treatment according to established guidelines. PMID:21289954

  18. A generalized model on the evaluation of entropy and entropy of mixing of liquid Na-Sn alloys

    NASA Astrophysics Data System (ADS)

    Satpathy, Alok; Sengupta, Saumendu

    2017-01-01

    Recently proposed theory of entropy of mixing of the structurally inhomogeneous binary liquid alloys of alkali metals and group-IV elements is applied successfully to the liquid Na-Sn alloy. This alloy indicates chemical short range ordering (CSRO) i.e. exhibits partially salt like characteristics due to strong tendencies to compound formation, in the solid as well as in the liquid state. So, the generalized model for entropy of charged-hard-spheres mixture of arbitrary charge and size is employed to evaluate entropies of mixing, treating the sample as partially charge transfer system. The computed entropies of mixing are in excellent agreement with the experimental data.

  19. The Correlation of Standard Entropy with Enthalpy Supplied from 0 to 298.15 K

    ERIC Educational Resources Information Center

    Lambert, Frank L.; Leff, Harvey S.

    2009-01-01

    As a substance is heated at constant pressure from near 0 K to 298 K, each incremental enthalpy increase, dH, alters entropy by dH/T, bringing it from approximately zero to its standard molar entropy S degrees. Using heat capacity data for 32 solids and CODATA results for another 45, we found a roughly linear relationship between S degrees and…

  20. The Correlation of Standard Entropy with Enthalpy Supplied from 0 to 298.15 K

    ERIC Educational Resources Information Center

    Lambert, Frank L.; Leff, Harvey S.

    2009-01-01

    As a substance is heated at constant pressure from near 0 K to 298 K, each incremental enthalpy increase, dH, alters entropy by dH/T, bringing it from approximately zero to its standard molar entropy S degrees. Using heat capacity data for 32 solids and CODATA results for another 45, we found a roughly linear relationship between S degrees and…

  1. Angle Class II, subdivision, with agenesis of mandibular second molars and extrusion of maxillary second molars *

    PubMed Central

    Tavares, Rubens Rodrigues

    2015-01-01

    This clinical case reports the treatment of an Angle Class II malocclusion in a young woman with a balanced face affected by agenesis of second and third mandibular molars and subsequent extrusion of second maxillary molars. The atypical and peculiar occlusal anomaly led to individualized treatment proposed in order to normalize dental malpositions, with subsequent rehabilitation of edentulous areas by means of a multidisciplinary approach. This case was presented to the Brazilian Board of Orthodontics and Dentofacial Orthopedics (BBO) in partial fulfillment of the requirements for obtaining the title of certified by the BBO. PMID:25992995

  2. Increase of Boltzmann entropy in a quantum forced harmonic oscillator

    NASA Astrophysics Data System (ADS)

    Campisi, Michele

    2008-11-01

    Recently, a quantum-mechanical proof of the increase of Boltzmann entropy in quantum systems that are coupled to an external classical source of work has been given. Here we illustrate this result by applying it to a forced quantum harmonic oscillator. We show plots of the actual temporal evolution of work and entropy for various forcing protocols. We note that entropy and work can be partially or even fully returned to the source, although both work and entropy balances are non-negative at all times in accordance with the minimal work principle and the Clausius principle, respectively. A necessary condition for the increase of entropy is that the initial distribution is decreasing (e.g., canonical). We show evidence that for a nondecreasing distribution (e.g., microcanonical), the quantum expectation of entropy may decrease slightly. Interestingly, the classical expectation of entropy cannot decrease, irrespective of the initial distribution, in the forced harmonic oscillator.

  3. Increase of Boltzmann entropy in a quantum forced harmonic oscillator.

    PubMed

    Campisi, Michele

    2008-11-01

    Recently, a quantum-mechanical proof of the increase of Boltzmann entropy in quantum systems that are coupled to an external classical source of work has been given. Here we illustrate this result by applying it to a forced quantum harmonic oscillator. We show plots of the actual temporal evolution of work and entropy for various forcing protocols. We note that entropy and work can be partially or even fully returned to the source, although both work and entropy balances are non-negative at all times in accordance with the minimal work principle and the Clausius principle, respectively. A necessary condition for the increase of entropy is that the initial distribution is decreasing (e.g., canonical). We show evidence that for a nondecreasing distribution (e.g., microcanonical), the quantum expectation of entropy may decrease slightly. Interestingly, the classical expectation of entropy cannot decrease, irrespective of the initial distribution, in the forced harmonic oscillator.

  4. Generalized entanglement entropy

    NASA Astrophysics Data System (ADS)

    Taylor, Marika

    2016-07-01

    We discuss two measures of entanglement in quantum field theory and their holographic realizations. For field theories admitting a global symmetry, we introduce a global symmetry entanglement entropy, associated with the partitioning of the symmetry group. This quantity is proposed to be related to the generalized holographic entanglement entropy defined via the partitioning of the internal space of the bulk geometry. Thesecond measure of quantum field theory entanglement is the field space entanglement entropy, obtained by integrating out a subset of the quantum fields. We argue that field space entanglement entropy cannot be precisely realised geometrically in a holographic dual. However, for holographic geometries with interior decoupling regions, the differential entropy provides a close analogue to the field space entanglement entropy. We derive generic descriptions of such inner throat regions in terms of gravity coupled to massive scalars and show how the differential entropy in the throat captures features of the field space entanglement entropy.

  5. Ectopic molar pregnancy: a case report.

    PubMed

    Bousfiha, Najoua; Erarhay, Sanaa; Louba, Adnane; Saadi, Hanan; Bouchikhi, Chahrazad; Banani, Abdelaziz; El Fatemi, Hind; Sekkal, Med; Laamarti, Afaf

    2012-01-01

    The incidence of hydatidiform moles is 1 per 1,000 pregnancies. Ectopic pregnancy occurs in 20 per 1,000 pregnancies. Thus, the incidence of the ectopic molar gestation is very rare. We report a case of tubal molar pregnancy diagnosed at the systematic histology exam of an ectopic pregnancy. We report the case of 32 years old nulliparus women who presented a vaginal bleeding, lower abdominal pain and 6 weeks amenorrhea corresponding to the last menstrual period. At the clinical examination, the arterial pressure was 100/60 mmHG. The gynecological examination was difficult because of lower abdominal pain. Serum gonadotropin activity was 3454 ui/l. Pelvic ultrasound revealed an irregular echogenic mass in the left adnexa. Diagnostic laparoscopy revealed a left-sided unruptured ampullary ectopic pregnancy. A left laparoscopic salpingectomy was performed. The systematic histologic test identified an ectopic partial molar pregnancy, which was confirmed by DNA ploidy image analysis. The patient was followed with weekly quantitative B-hCG titers until three successive B-hCG levels were negative. It is pertinent that clinicians take routine histological examination of tubal specimens in ectopic pregnancy very seriously in order to diagnose cases of ectopic molar gestations early and mount appropriate post treatment surveillance.

  6. Modeling loop entropy.

    PubMed

    Chirikjian, Gregory S

    2011-01-01

    Proteins fold from a highly disordered state into a highly ordered one. Traditionally, the folding problem has been stated as one of predicting "the" tertiary structure from sequential information. However, new evidence suggests that the ensemble of unfolded forms may not be as disordered as once believed, and that the native form of many proteins may not be described by a single conformation, but rather an ensemble of its own. Quantifying the relative disorder in the folded and unfolded ensembles as an entropy difference may therefore shed light on the folding process. One issue that clouds discussions of "entropy" is that many different kinds of entropy can be defined: entropy associated with overall translational and rotational Brownian motion, configurational entropy, vibrational entropy, conformational entropy computed in internal or Cartesian coordinates (which can even be different from each other), conformational entropy computed on a lattice, each of the above with different solvation and solvent models, thermodynamic entropy measured experimentally, etc. The focus of this work is the conformational entropy of coil/loop regions in proteins. New mathematical modeling tools for the approximation of changes in conformational entropy during transition from unfolded to folded ensembles are introduced. In particular, models for computing lower and upper bounds on entropy for polymer models of polypeptide coils both with and without end constraints are presented. The methods reviewed here include kinematics (the mathematics of rigid-body motions), classical statistical mechanics, and information theory.

  7. Entropy Is Simple, Qualitatively.

    ERIC Educational Resources Information Center

    Lambert, Frank L.

    2002-01-01

    Suggests that qualitatively, entropy is simple. Entropy increase from a macro viewpoint is a measure of the dispersal of energy from localized to spread out at a temperature T. Fundamentally based on statistical and quantum mechanics, this approach is superior to the non-fundamental "disorder" as a descriptor of entropy change. (MM)

  8. Entropy: Order or Information

    ERIC Educational Resources Information Center

    Ben-Naim, Arieh

    2011-01-01

    Changes in entropy can "sometimes" be interpreted in terms of changes in disorder. On the other hand, changes in entropy can "always" be interpreted in terms of changes in Shannon's measure of information. Mixing and demixing processes are used to highlight the pitfalls in the association of entropy with disorder. (Contains 3 figures.)

  9. Entropy: Order or Information

    ERIC Educational Resources Information Center

    Ben-Naim, Arieh

    2011-01-01

    Changes in entropy can "sometimes" be interpreted in terms of changes in disorder. On the other hand, changes in entropy can "always" be interpreted in terms of changes in Shannon's measure of information. Mixing and demixing processes are used to highlight the pitfalls in the association of entropy with disorder. (Contains 3 figures.)

  10. Entropy Is Simple, Qualitatively.

    ERIC Educational Resources Information Center

    Lambert, Frank L.

    2002-01-01

    Suggests that qualitatively, entropy is simple. Entropy increase from a macro viewpoint is a measure of the dispersal of energy from localized to spread out at a temperature T. Fundamentally based on statistical and quantum mechanics, this approach is superior to the non-fundamental "disorder" as a descriptor of entropy change. (MM)

  11. Entropy, a Protean Concept

    NASA Astrophysics Data System (ADS)

    Balian, Roger

    We review at a tutorial level the many aspects of the concept of entropy and their interrelations, in thermodynamics, information theory, probability theory and statistical physics. The consideration of relevant entropies and the identification of entropy with missing information enlighten the paradoxes of irreversibility and of Maxwell's demon.

  12. Partial hydatidiform mole and coexisting viable twin pregnancy.

    PubMed

    Tay, Ee Tein

    2013-12-01

    Twin partial hydatidiform molar pregnancy with a viable fetus is an uncommon occurrence. Presentations of molar pregnancies include vaginal bleeding, unusually elevated β-human chorionic gonadotropin level, and preeclampsia. Previous descriptions of twin molar and fetus pregnancies in the literature have been described in the outpatient obstetric setting. We present a case of partial molar pregnancy with a viable fetus detected with emergency ultrasound in a pediatric emergency department.

  13. Application of the Third Molar Eruption Predictor to periapical radiographs.

    PubMed

    Ventä, I; Schou, S

    2001-06-01

    The aim of this study was to test whether the Third Molar Eruption Predictor, developed for panoramic radiographs, can also be applied to periapical radiographs. The Third Molar Eruption Predictor is a transparent device (US patent 5,816,814), not commercially available, and developed for prediction of future eruption or impaction of third molars. The material consisted of periapical radiographs of mandibular third molars taken from the lateral projection without angulation of the central beam. The radiographs taken at the mean age of 20.6 years (SD +/- 1.4 years) were retrospectively available from a four-year follow-up study of third molars carried out at the University of Copenhagen, Denmark. Initially unerupted or partially erupted third molars (n=43) in 28 dental students were analyzed. Clinical statuses of the third molars were available at baseline and four years later. The device was calibrated using the method of simple proportions and Bayes' Decision Theory. The predictions made with the calibrated device were in conformity with the final clinical outcome in 84% of the cases. It was concluded that the Third Molar Eruption Predictor may also be used on periapical radiographs after calibration of the device.

  14. Taurodontism in deciduous molars

    PubMed Central

    Bafna, Yash; Kambalimath, H V; Khandelwal, Vishal; Nayak, Prathibha

    2013-01-01

    Taurodont teeth are characterised by large pulp chambers at the expense of roots. An enlarged pulp chamber, apical displacement of the pulpal floor and no constriction at the level of the cement-enamel junction are the characteristic features of taurodont tooth. It appears more frequently as an isolated anomaly but its association with syndromes and other abnormalities have also been reported. Permanent dentition is more commonly affected than deciduous dentition. This paper presents a case report of taurodontism in relation to mandibular deciduous second molars. PMID:23737594

  15. Molar incisor hypomineralization.

    PubMed

    Takahashi, Karine; Correia, Adriana de Sales Cunha; Cunha, Robson Frederico

    2009-01-01

    Enamel defects are common alterations that can occur in both the primary or permanent dentition. A range of etiological factors related to this pathology can be found in the literature. Molar Incisor Hypomineralization (MIH) is a kind of enamel defect alteration that requires complex treatment solutions, and for this reason, it is of great clinical interest for dental practice. This article describes the management of a clinical case of MIH in a 7-year-old child. The different treatment options depending on the extension of the defect, the degree of tooth eruption and the hygiene and diet habits of the patient are also discussed.

  16. Modeling Loop Entropy

    PubMed Central

    Chirikjian, Gregory S.

    2011-01-01

    Proteins fold from a highly disordered state into a highly ordered one. Traditionally, the folding problem has been stated as one of predicting ‘the’ tertiary structure from sequential information. However, new evidence suggests that the ensemble of unfolded forms may not be as disordered as once believed, and that the native form of many proteins may not be described by a single conformation, but rather an ensemble of its own. Quantifying the relative disorder in the folded and unfolded ensembles as an entropy difference may therefore shed light on the folding process. One issue that clouds discussions of ‘entropy’ is that many different kinds of entropy can be defined: entropy associated with overall translational and rotational Brownian motion, configurational entropy, vibrational entropy, conformational entropy computed in internal or Cartesian coordinates (which can even be different from each other), conformational entropy computed on a lattice; each of the above with different solvation and solvent models; thermodynamic entropy measured experimentally, etc. The focus of this work is the conformational entropy of coil/loop regions in proteins. New mathematical modeling tools for the approximation of changes in conformational entropy during transition from unfolded to folded ensembles are introduced. In particular, models for computing lower and upper bounds on entropy for polymer models of polypeptide coils both with and without end constraints are presented. The methods reviewed here include kinematics (the mathematics of rigid-body motions), classical statistical mechanics and information theory. PMID:21187223

  17. RNA Thermodynamic Structural Entropy

    PubMed Central

    Garcia-Martin, Juan Antonio; Clote, Peter

    2015-01-01

    Conformational entropy for atomic-level, three dimensional biomolecules is known experimentally to play an important role in protein-ligand discrimination, yet reliable computation of entropy remains a difficult problem. Here we describe the first two accurate and efficient algorithms to compute the conformational entropy for RNA secondary structures, with respect to the Turner energy model, where free energy parameters are determined from UV absorption experiments. An algorithm to compute the derivational entropy for RNA secondary structures had previously been introduced, using stochastic context free grammars (SCFGs). However, the numerical value of derivational entropy depends heavily on the chosen context free grammar and on the training set used to estimate rule probabilities. Using data from the Rfam database, we determine that both of our thermodynamic methods, which agree in numerical value, are substantially faster than the SCFG method. Thermodynamic structural entropy is much smaller than derivational entropy, and the correlation between length-normalized thermodynamic entropy and derivational entropy is moderately weak to poor. In applications, we plot the structural entropy as a function of temperature for known thermoswitches, such as the repression of heat shock gene expression (ROSE) element, we determine that the correlation between hammerhead ribozyme cleavage activity and total free energy is improved by including an additional free energy term arising from conformational entropy, and we plot the structural entropy of windows of the HIV-1 genome. Our software RNAentropy can compute structural entropy for any user-specified temperature, and supports both the Turner’99 and Turner’04 energy parameters. It follows that RNAentropy is state-of-the-art software to compute RNA secondary structure conformational entropy. Source code is available at https://github.com/clotelab/RNAentropy/; a full web server is available at http

  18. RNA Thermodynamic Structural Entropy.

    PubMed

    Garcia-Martin, Juan Antonio; Clote, Peter

    2015-01-01

    Conformational entropy for atomic-level, three dimensional biomolecules is known experimentally to play an important role in protein-ligand discrimination, yet reliable computation of entropy remains a difficult problem. Here we describe the first two accurate and efficient algorithms to compute the conformational entropy for RNA secondary structures, with respect to the Turner energy model, where free energy parameters are determined from UV absorption experiments. An algorithm to compute the derivational entropy for RNA secondary structures had previously been introduced, using stochastic context free grammars (SCFGs). However, the numerical value of derivational entropy depends heavily on the chosen context free grammar and on the training set used to estimate rule probabilities. Using data from the Rfam database, we determine that both of our thermodynamic methods, which agree in numerical value, are substantially faster than the SCFG method. Thermodynamic structural entropy is much smaller than derivational entropy, and the correlation between length-normalized thermodynamic entropy and derivational entropy is moderately weak to poor. In applications, we plot the structural entropy as a function of temperature for known thermoswitches, such as the repression of heat shock gene expression (ROSE) element, we determine that the correlation between hammerhead ribozyme cleavage activity and total free energy is improved by including an additional free energy term arising from conformational entropy, and we plot the structural entropy of windows of the HIV-1 genome. Our software RNAentropy can compute structural entropy for any user-specified temperature, and supports both the Turner'99 and Turner'04 energy parameters. It follows that RNAentropy is state-of-the-art software to compute RNA secondary structure conformational entropy. Source code is available at https://github.com/clotelab/RNAentropy/; a full web server is available at http

  19. Microcanonical origin of the maximum entropy principle for open systems.

    PubMed

    Lee, Julian; Pressé, Steve

    2012-10-01

    There are two distinct approaches for deriving the canonical ensemble. The canonical ensemble either follows as a special limit of the microcanonical ensemble or alternatively follows from the maximum entropy principle. We show the equivalence of these two approaches by applying the maximum entropy formulation to a closed universe consisting of an open system plus bath. We show that the target function for deriving the canonical distribution emerges as a natural consequence of partial maximization of the entropy over the bath degrees of freedom alone. By extending this mathematical formalism to dynamical paths rather than equilibrium ensembles, the result provides an alternative justification for the principle of path entropy maximization as well.

  20. Relative entropy equals bulk relative entropy

    SciTech Connect

    Jafferis, Daniel L.; Lewkowycz, Aitor; Maldacena, Juan; Suh, S. Josephine

    2016-06-01

    We consider the gravity dual of the modular Hamiltonian associated to a general subregion of a boundary theory. We use it to argue that the relative entropy of nearby states is given by the relative entropy in the bulk, to leading order in the bulk gravitational coupling. We also argue that the boundary modular flow is dual to the bulk modular flow in the entanglement wedge, with implications for entanglement wedge reconstruction.

  1. Molar Incisor Hypomineralization.

    PubMed

    Rao, Murali H; Aluru, Srikanth C; Jayam, Cheranjeevi; Bandlapalli, Anila; Patel, Nikunj

    2016-07-01

    Molar incisor hypomineralization (MIH) is a developmental defect affecting teeth. High prevalence rates of MIH and its clinical implications are significant for both the patients and clinicians. A wide variation in defect prevalence (2.4-40.2%) is reported. It seems to differ with regions and various birth cohorts. Some of the recent prevalence studies are tabulated. Patient implications include hypersensitive teeth, rapid progression of caries, mastication impairment due to rapid attrition, and esthetic repercussions. Implications for clinicians include complexity in treatment planning and treatment implementation, poor prognosis of the restorations, difficulty in achieving pain control during treatment, and behavior management problems. Intention of this paper is to review the etio-pathogenesis, prevalence, clinical features, diagnostic features, and eventually present a sequential treatment approach, i.e., in accordance with current clinical practice guidelines.

  2. Entropy and econophysics

    NASA Astrophysics Data System (ADS)

    Rosser, J. Barkley

    2016-12-01

    Entropy is a central concept of statistical mechanics, which is the main branch of physics that underlies econophysics, the application of physics concepts to understand economic phenomena. It enters into econophysics both in an ontological way through the Second Law of Thermodynamics as this drives the world economy from its ecological foundations as solar energy passes through food chains in dissipative process of entropy rising and production fundamentally involving the replacement of lower entropy energy states with higher entropy ones. In contrast the mathematics of entropy as appearing in information theory becomes the basis for modeling financial market dynamics as well as income and wealth distribution dynamics. It also provides the basis for an alternative view of stochastic price equilibria in economics, as well providing a crucial link between econophysics and sociophysics, keeping in mind the essential unity of the various concepts of entropy.

  3. Third molars as an acute problem in Finnish university students.

    PubMed

    Ventä, I; Turtola, L; Murtomaa, H; Ylipaavalniemi, P

    1993-08-01

    The study was carried out to determine the risk of acute disease of third molars in young adult patients. The subjects in this case-control study were 100 consecutive university students who complained of third molar problems when making an appointment. The third molars were mostly mandibular, partly erupted, and distoangularly oriented. Severity of discomfort and interference with daily activities were graded by the patients on average as 5.0 (SD +/- 2.7) and 3.6 (SD +/- 2.9), on a scale from 0 through 10. Distoangular lower third molars caused the most discomfort and interfered most with activities of patients. The risk of acute disease in patients with distoangularly oriented third molars was 3.6 times that in other patients. Bivariate analysis showed that if the follicle of a distoangular third molar were enlarged, the risk of acquiring acute disease was 44 times that in other patients. It was concluded that early removal of partially erupted and distoangularly oriented lower third molars is recommended, especially when they are associated with an enlarged follicle.

  4. Entropy Transfer of Quantum Gravity Information Processing

    NASA Astrophysics Data System (ADS)

    Gyongyosi, Laszlo; Imre, Sandor

    2015-05-01

    We introduce the term smooth entanglement entropy transfer, a phenomenon that is a consequence of the causality-cancellation property of the quantum gravity environment. The causality-cancellation of the quantum gravity space removes the causal dependencies of the local systems. We study the physical effects of the causality-cancellation and show that it stimulates entropy transfer between the quantum gravity environment and the independent local systems of the quantum gravity space. The entropy transfer reduces the entropies of the contributing local systems and increases the entropy of the quantum gravity environment. We discuss the space-time geometry structure of the quantum gravity environment and the local quantum systems. We propose the space-time geometry model of the smooth entropy transfer. We reveal on a smooth Cauchy slice that the space-time geometry of the quantum gravity environment dynamically adapts to the vanishing causality. We prove that the Cauchy area expansion, along with the dilation of the Rindler horizon area of the quantum gravity environment, is a corollary of the causality-cancellation of the quantum gravity environment. This work was partially supported by the GOP-1.1.1-11-2012-0092 (Secure quantum key distribution between two units on optical fiber network) project sponsored by the EU and European Structural Fund, and by the COST Action MP1006.

  5. Remarks on entanglement entropy for gauge fields

    NASA Astrophysics Data System (ADS)

    Casini, Horacio; Huerta, Marina; Rosabal, José Alejandro

    2014-04-01

    In gauge theories the presence of constraints can obstruct expressing the global Hilbert space as a tensor product of the Hilbert spaces corresponding to degrees of freedom localized in complementary regions. In algebraic terms, this is due to the presence of a center—a set of operators which commute with all others—in the gauge invariant operator algebra corresponding to a finite region. A unique entropy can be assigned to algebras with a center, giving a place to a local entropy in lattice gauge theories. However, ambiguities arise on the correspondence between algebras and regions. In particular, it is always possible to choose (in many different ways) local algebras with a trivial center, and hence a genuine entanglement entropy, for any region. These choices are in correspondence with maximal trees of links on the boundary, which can be interpreted as partial gauge fixings. This interpretation entails a gauge fixing dependence of the entanglement entropy. In the continuum limit, however, ambiguities in the entropy are given by terms local on the boundary of the region, in such a way relative entropy and mutual information are finite, universal, and gauge independent quantities.

  6. Controversy of the third molars.

    PubMed

    Pitekova, L; Satko, I

    2009-01-01

    Third molars are teeth that have little functional value and a relatively high rate of associated pain and disease. Their value as a part of the dentition of modern people is dubious. Our aim is to review the evolution, morbidity and complications of the third molars (Ref. 19). Full Text (Free, PDF) www.bmj.sk.

  7. Partial Pressures of Te2 and Thermodynamic Properties of Ga-Te System

    NASA Technical Reports Server (NTRS)

    Su, Ching-Hua; Curreri, Peter A. (Technical Monitor)

    2001-01-01

    The partial pressures of Te2 in equilibrium with Ga(1-x)Te(x) samples were measured by optical absorption technique from 450 to 1100 C for compositions, x, between 0.333 and 0.612. To establish the relationship between the partial pressure of Te, and the measured optical absorbance, the calibration runs of a pure Te sample were also conducted to determine the Beer's Law constants. The partial pressures of Te2 in equilibrium with the GaTe(s) and Ga2Te3(s)compounds, or the so-called three-phase curves, were established. These partial pressure data imply the existence of the Ga3Te4(s) compound. From the partial pressures of Te2 over the Ga-Te melts, partial molar enthalpy and entropy of mixing for Te were derived and they agree reasonable well with the published data. The activities of Te in the Ga-Te melts were also derived from the measured partial pressures of Te2. These data agree well with most of the previous results. The possible reason for the high activity of Te measured for x less than 0.60 is discussed.

  8. Peri-operative second molar tube failure during orthognathic surgery: two case reports.

    PubMed

    Wenger, N A; Atack, N E; Mitchell, C N; Ireland, A J

    2007-06-01

    With improvements in bonding techniques, bracket base design and bond strengths, molar tubes are becoming more popular in orthodontics. Molar tubes make an attractive alternative to conventional banding due to a reduction in clinical bonding time and ease of placement on partially erupted teeth. The use of molar tubes negates the need for orthodontic separation and subsequent cementation of bands, and offers improved periodontal health. Their use on terminal molars, however, should be limited to non-orthognathic cases. This paper presents two cases of peri-operative second molar tube failure during orthognathic surgery. They are presented in the hope that it will highlight the importance of banding the distal terminal molar in orthognathic cases to prevent loss of molar tubes and peri-operative contamination of the surgical wound site.

  9. Wehrl entropy, Lieb conjecture, and entanglement monotones

    SciTech Connect

    Mintert, Florian; Zyczkowski, Karol

    2004-02-01

    We propose to quantify the entanglement of pure states of NxN bipartite quantum systems by defining its Husimi distribution with respect to SU(N)xSU(N) coherent states. The Wehrl entropy is minimal if and only if the analyzed pure state is separable. The excess of the Wehrl entropy is shown to be equal to the subentropy of the mixed state obtained by partial trace of the bipartite pure state. This quantity, as well as the generalized (Renyi) subentropies, are proved to be Schur concave, so they are entanglement monotones and may be used as alternative measures of entanglement.

  10. Entropy in Rhetoric.

    ERIC Educational Resources Information Center

    Marder, Daniel

    The Second Law of Thermodynamics demonstrates the idea of entropy, the tendency of ordered energy to free itself and thus break apart the system that contains it and dissipate that system into chaos. When applied to communications theory, entropy increases not only with noise but with the density of information--particles of possible meaning…

  11. The Holographic Entropy Cone

    SciTech Connect

    Bao, Ning; Nezami, Sepehr; Ooguri, Hirosi; Stoica, Bogdan; Sully, James; Walter, Michael

    2015-09-21

    We initiate a systematic enumeration and classification of entropy inequalities satisfied by the Ryu-Takayanagi formula for conformal field theory states with smooth holographic dual geometries. For 2, 3, and 4 regions, we prove that the strong subadditivity and the monogamy of mutual information give the complete set of inequalities. This is in contrast to the situation for generic quantum systems, where a complete set of entropy inequalities is not known for 4 or more regions. We also find an infinite new family of inequalities applicable to 5 or more regions. The set of all holographic entropy inequalities bounds the phase space of Ryu-Takayanagi entropies, defining the holographic entropy cone. We characterize this entropy cone by reducing geometries to minimal graph models that encode the possible cutting and gluing relations of minimal surfaces. We find that, for a fixed number of regions, there are only finitely many independent entropy inequalities. To establish new holographic entropy inequalities, we introduce a combinatorial proof technique that may also be of independent interest in Riemannian geometry and graph theory.

  12. The Holographic Entropy Cone

    DOE PAGES

    Bao, Ning; Nezami, Sepehr; Ooguri, Hirosi; ...

    2015-09-21

    We initiate a systematic enumeration and classification of entropy inequalities satisfied by the Ryu-Takayanagi formula for conformal field theory states with smooth holographic dual geometries. For 2, 3, and 4 regions, we prove that the strong subadditivity and the monogamy of mutual information give the complete set of inequalities. This is in contrast to the situation for generic quantum systems, where a complete set of entropy inequalities is not known for 4 or more regions. We also find an infinite new family of inequalities applicable to 5 or more regions. The set of all holographic entropy inequalities bounds the phasemore » space of Ryu-Takayanagi entropies, defining the holographic entropy cone. We characterize this entropy cone by reducing geometries to minimal graph models that encode the possible cutting and gluing relations of minimal surfaces. We find that, for a fixed number of regions, there are only finitely many independent entropy inequalities. To establish new holographic entropy inequalities, we introduce a combinatorial proof technique that may also be of independent interest in Riemannian geometry and graph theory.« less

  13. Black hole entropy quantization.

    PubMed

    Corichi, Alejandro; Díaz-Polo, Jacobo; Fernández-Borja, Enrique

    2007-05-04

    Ever since the pioneering works of Bekenstein and Hawking, black hole entropy has been known to have a quantum origin. Furthermore, it has long been argued by Bekenstein that entropy should be quantized in discrete (equidistant) steps given its identification with horizon area in (semi-)classical general relativity and the properties of area as an adiabatic invariant. This lead to the suggestion that the black hole area should also be quantized in equidistant steps to account for the discrete black hole entropy. Here we shall show that loop quantum gravity, in which area is not quantized in equidistant steps, can nevertheless be consistent with Bekenstein's equidistant entropy proposal in a subtle way. For that we perform a detailed analysis of the number of microstates compatible with a given area and show consistency with the Bekenstein framework when an oscillatory behavior in the entropy-area relation is properly interpreted.

  14. Infinite Shannon entropy

    NASA Astrophysics Data System (ADS)

    Baccetti, Valentina; Visser, Matt

    2013-04-01

    Even if a probability distribution is properly normalizable, its associated Shannon (or von Neumann) entropy can easily be infinite. We carefully analyze conditions under which this phenomenon can occur. Roughly speaking, this happens when arbitrarily small amounts of probability are dispersed into an infinite number of states; we shall quantify this observation and make it precise. We develop several particularly simple, elementary, and useful bounds, and also provide some asymptotic estimates, leading to necessary and sufficient conditions for the occurrence of infinite Shannon entropy. We go to some effort to keep technical computations as simple and conceptually clear as possible. In particular, we shall see that large entropies cannot be localized in state space; large entropies can only be supported on an exponentially large number of states. We are for the time being interested in single-channel Shannon entropy in the information theoretic sense, not entropy in a stochastic field theory or quantum field theory defined over some configuration space, on the grounds that this simple problem is a necessary precursor to understanding infinite entropy in a field theoretic context.

  15. Entropy Bounds and Entanglement

    NASA Astrophysics Data System (ADS)

    Fisher, Zachary

    The generalized covariant entropy bound, or Bousso bound, is a holographic bound on the entropy of a region of space in a gravitational theory. It bounds the entropy passing through certain null surfaces. The bound remains non-trivial in the weak-gravity limit, and provides non-trivial constraints on the entropy of ordinary quantum states even in a regime where gravity is negligible. In the first half of this thesis, we present a proof of the Bousso bound in the weak-gravity regime within the framework of quantum field theory. The bound uses techniques from quantum information theory which relate the energy and entropy of quantum states. We present two proofs of the bound in free and interacting field theory. In the second half, we present a generalization of the Bousso bound called the quantum focussing conjecture. Our conjecture is a bound on the rate of entropy generation in a quantum field theory coupled semiclassically to gravity. The conjecture unifies and generalizes several ideas in holography. In particular, the quantum focussing conjecture implies a bound on entropies which is similar to, but subtly different from, the Bousso bound proven in the first half. The quantum focussing conjecture implies a novel non-gravitational energy condition, the quantum null energy condition, which gives a point-wise lower bound on the null-null component of the stress tensor of quantum matter. We give a proof of this bound in the context of free and superrenormalizable bosonic quantum field theory.

  16. Molar incisor hypomineralisation.

    PubMed

    Taylor, Greig D

    2017-03-01

    Data sourcesThe Medline and Embase databases and hand searches in the journals International Journal of Paediatric Dentistry and European Archives of Paediatric Dentistry.Study selectionEnglish language cohort and case-control studies.Data extraction and synthesisStudy selection was carried out independently by two reviewers with data abstraction being conducted by a single reviewer and checked by a second reviewer. Risk of bias was assessed using a modified version of the Newcastle-Ottawa Scale (NOS). Adjusted (aOR) and unadjusted odds ratios (uOR), P-values and 95% confidence intervals (CI) were obtained from the studies. Meta-analysis was not conducted.ResultsTwenty-eight studies were included; 25 reported on MIH, three on hypomineralised second primary molars (HSPM). Nineteen of the studies were of cohort design (six prospective,13 retrospective) and nine were case controls. There was little evidence of an association between the most frequently investigated prenatal factors (smoking, maternal illness, maternal medication, maternal stress) and MIH. Similarly there was little evidence of an association between MIH and perinatal factors such as prematurity, low birth weight, caesarean delivery and birth complications. Early childhood illness, up to three or four years of age, was widely investigated, with six studies reporting a crude association. Associations between antibiotics, anti-asthma medication and breastfeeding were also evaluated. Only three studies looked at HSPM; one study suggested that maternal antibiotic use during pregnancy is unlikely to be associated with HSPM but maternal alcohol intake may be. Another study reported possible associations with a large number of factors, with perinatal factors and neonatal illness being most common, followed by prenatal factors.ConclusionsPrenatal and perinatal factors are infrequently associated with MIH. However, despite a lack of prospective studies, early childhood illness (in particular fever) appears to

  17. Spin and elastic contributions to isothermal entropy change

    NASA Astrophysics Data System (ADS)

    Mukherjee, T.; Skomski, R.; Michalski, S.; Sellmyer, D. J.; Binek, Ch.

    2012-04-01

    Statistical considerations of ensembles of localized magnetic moments reveal an upper bound of the isothermal entropy change when only the magnetic degrees of freedom are considered. In this case, the maximum molar isothermal entropy change is determined by the spin multiplicity and is equal to Rln(2J + 1), where J is the angular momentum of an individual atom. However, in materials with giant magnetocaloric effect, the isothermal field-induced entropy change goes beyond the spin-multiplicity limit due to field-activated elastic degrees of freedom. Recently, we investigated a model of pairs of exchange-coupled Ising spins with variable real-space positions. We showed, within a classical approximation for the elastic degree of freedom, that a vibrational entropy contribution can be activated via applied magnetic fields. Here we quantify the impact of quantum corrections in the low-temperature limit. We compare calculations that include elastic interaction with the rigid exchange model in the high-temperature limit. We find that quantum effects provide quantitative corrections in the low-temperature limit. In addition we show that the elastic contributions to the isothermal entropy change can be additive but, remarkably, it can also give rise to reduced isothermal entropy change in certain temperature regions.

  18. Maximum entropy analysis of NMR data of flexible multirotor molecules partially oriented in nematic solution: 2,2':5',2″-terthiophene, 2,2'- and 3,3'-dithiophene

    NASA Astrophysics Data System (ADS)

    Caldarelli, Stefano; Catalano, Donata; Di Bari, Lorenzo; Lumetti, Marco; Ciofalo, Maurizio; Alberto Veracini, Carlo

    1994-07-01

    The dipolar couplings observed by NMR spectroscopy of solutes in nematic solvents (LX-NMR) are used to build up the maximum entropy (ME) probability distribution function of the variables describing the orientational and internal motion of the molecule. The ME conformational distributions of 2,2'- and 3,3'-dithiophene and 2,2':5',2″-terthiophene (α-terthienyl)thus obtained are compared with the results of previous studies. The 2,2'- and 3,3'-dithiophene molecules exhibit equilibria among cisoid and transoid forms; the probability maxima correspond to planar and twisted conformers for 2,2'- or 3,3'-dithiophene, respectively, 2,2':5',2″-Terthiophene has two internal degrees of freedom; the ME approach indicates that the trans, trans and cis, trans planar conformations are the most probable. The correlation between the two intramolecular rotations is also discussed.

  19. Absolute Equilibrium Entropy

    NASA Technical Reports Server (NTRS)

    Shebalin, John V.

    1997-01-01

    The entropy associated with absolute equilibrium ensemble theories of ideal, homogeneous, fluid and magneto-fluid turbulence is discussed and the three-dimensional fluid case is examined in detail. A sigma-function is defined, whose minimum value with respect to global parameters is the entropy. A comparison is made between the use of global functions sigma and phase functions H (associated with the development of various H-theorems of ideal turbulence). It is shown that the two approaches are complimentary though conceptually different: H-theorems show that an isolated system tends to equilibrium while sigma-functions allow the demonstration that entropy never decreases when two previously isolated systems are combined. This provides a more complete picture of entropy in the statistical mechanics of ideal fluids.

  20. The Mystique of Entropy.

    ERIC Educational Resources Information Center

    Kyle, Benjamin G.

    1988-01-01

    Illustrates qualitative and metaphoric applications of entropy in the areas of cosmology, the birth and death of the universe and time; life and evolution; literature and art; and social science. (RT)

  1. Entropy of international trades

    NASA Astrophysics Data System (ADS)

    Oh, Chang-Young; Lee, D.-S.

    2017-05-01

    The organization of international trades is highly complex under the collective efforts towards economic profits of participating countries given inhomogeneous resources for production. Considering the trade flux as the probability of exporting a product from a country to another, we evaluate the entropy of the world trades in the period 1950-2000. The trade entropy has increased with time, and we show that it is mainly due to the extension of trade partnership. For a given number of trade partners, the mean trade entropy is about 60% of the maximum possible entropy, independent of time, which can be regarded as a characteristic of the trade fluxes' heterogeneity and is shown to be derived from the scaling and functional behaviors of the universal trade-flux distribution. The correlation and time evolution of the individual countries' gross-domestic products and the number of trade partners show that most countries achieved their economic growth partly by extending their trade relationship.

  2. The Mystique of Entropy.

    ERIC Educational Resources Information Center

    Kyle, Benjamin G.

    1988-01-01

    Illustrates qualitative and metaphoric applications of entropy in the areas of cosmology, the birth and death of the universe and time; life and evolution; literature and art; and social science. (RT)

  3. Laser assisted high entropy alloy coating on aluminum: Microstructural evolution

    SciTech Connect

    Katakam, Shravana; Joshi, Sameehan S.; Mridha, Sanghita; Mukherjee, Sundeep; Dahotre, Narendra B.

    2014-09-14

    High entropy alloy (Al-Fe-Co-Cr-Ni) coatings were synthesized using laser surface engineering on aluminum substrate. Electron diffraction analysis confirmed the formation of solid solution of body centered cubic high entropy alloy phase along with phases with long range periodic structures within the coating. Evolution of such type of microstructure was a result of kinetics associated with laser process, which generates higher temperatures and rapid cooling resulting in retention of high entropy alloy phase followed by reheating and/or annealing in subsequent passes of the laser track giving rise to partial decomposition. The partial decomposition resulted in formation of precipitates having layered morphology with a mixture of high entropy alloy rich phases, compounds, and long range ordered phases.

  4. Entropy of stochastic flows

    SciTech Connect

    Dorogovtsev, Andrei A

    2010-06-29

    For sets in a Hilbert space the concept of quadratic entropy is introduced. It is shown that this entropy is finite for the range of a stochastic flow of Brownian particles on R. This implies, in particular, the fact that the total time of the free travel in the Arratia flow of all particles that started from a bounded interval is finite. Bibliography: 10 titles.

  5. Anomalies and entanglement entropy

    NASA Astrophysics Data System (ADS)

    Nishioka, Tatsuma; Yarom, Amos

    2016-03-01

    We initiate a systematic study of entanglement and Rényi entropies in the presence of gauge and gravitational anomalies in even-dimensional quantum field theories. We argue that the mixed and gravitational anomalies are sensitive to boosts and obtain a closed form expression for their behavior under such transformations. Explicit constructions exhibiting the dependence of entanglement entropy on boosts is provided for theories on spacetimes with non-trivial magnetic fluxes and (or) non-vanishing Pontryagin classes.

  6. Information Entropy of Fullerenes.

    PubMed

    Sabirov, Denis Sh; Ōsawa, Eiji

    2015-08-24

    The reasons for the formation of the highly symmetric C60 molecule under nonequilibrium conditions are widely discussed as it dominates over numerous similar fullerene structures. In such conditions, evolution of structure rather than energy defines the processes. We have first studied the diversity of fullerenes in terms of information entropy. Sorting 2079 structures from An Atlas of Fullerenes [ Fowler , P. W. ; Manolopoulos , D. E. An Atlas of Fullerenes ; Oxford : Clarendon , 1995 . ], we have found that the information entropies of only 14 fullerenes (<1% of the studied structures) lie between the values of C60 and C70, the two most abundant fullerenes. Interestingly, buckminsterfullerene is the only fullerene with zero information entropy, i.e., an exclusive compound among the other members of the fullerene family. Such an efficient sorting demonstrates possible relevance of information entropy to chemical processes. For this reason, we have introduced an algorithm for calculating changes in information entropy at chemical transformations. The preliminary calculations of changes in information entropy at the selected fullerene reactions show good agreement with thermochemical data.

  7. The entropy of alloys.

    SciTech Connect

    Stan, M.

    2004-01-01

    A major problem in simulating thermodynamic properties of alloys is modeling the entropy. While configurational entropy is incorporated in most stability calculations, the other components, such as the vibrational and electronic entropy are often neglected or roughly estimated. In this work we propose a method of accounting for both configurational and vibrational entropy and discuss the electronic contribution for several actinide based alloys. The meaning of entropy in non-equilibrium thermodynamic processes is also discussed and illustrated for the case of phase transformations and diffusion. The influence of temperature on the enthalpy and free energy of delta-Pu-Ga phase, as resulted from Modified Embedded Atom Method (MEAM), and the influence of Ga content on the enthalpy and free energy of delta-Pu-Ga phase are discussed. The analysis of the thermodynamic properties of the fcc Pu-Ga phase, as calculated with MEAM shows that the vibrational entropy contribution to the free energy is ve ry important and non-linear with temperature. The free energy also changes with the Ga content.

  8. Renormalized entanglement entropy

    NASA Astrophysics Data System (ADS)

    Taylor, Marika; Woodhead, William

    2016-08-01

    We develop a renormalization method for holographic entanglement entropy based on area renormalization of entangling surfaces. The renormalized entanglement en-tropy is derived for entangling surfaces in asymptotically locally anti-de Sitter spacetimes in general dimensions and for entangling surfaces in four dimensional holographic renor-malization group flows. The renormalized entanglement entropy for disk regions in AdS 4 spacetimes agrees precisely with the holographically renormalized action for AdS 4 with spherical slicing and hence with the F quantity, in accordance with the Casini-Huerta-Myers map. We present a generic class of holographic RG flows associated with deforma-tions by operators of dimension 3 /2 < Δ < 5 /2 for which the F quantity increases along the RG flow, hence violating the strong version of the F theorem. We conclude by explaining how the renormalized entanglement entropy can be derived directly from the renormalized partition function using the replica trick i.e. our renormalization method for the entangle-ment entropy is inherited directly from that of the partition function. We show explicitly how the entanglement entropy counterterms can be derived from the standard holographic renormalization counterterms for asymptotically locally anti-de Sitter spacetimes.

  9. Entropy of quasiblack holes

    SciTech Connect

    Lemos, Jose P. S.; Zaslavskii, Oleg B.

    2010-03-15

    We trace the origin of the black hole entropy S, replacing a black hole by a quasiblack hole. Let the boundary of a static body approach its own gravitational radius, in such a way that a quasihorizon forms. We show that if the body is thermal with the temperature taking the Hawking value at the quasihorizon limit, it follows, in the nonextremal case, from the first law of thermodynamics that the entropy approaches the Bekenstein-Hawking value S=A/4. In this setup, the key role is played by the surface stresses on the quasihorizon and one finds that the entropy comes from the quasihorizon surface. Any distribution of matter inside the surface leads to the same universal value for the entropy in the quasihorizon limit. This can be of some help in the understanding of black hole entropy. Other similarities between black holes and quasiblack holes such as the mass formulas for both objects had been found previously. We also discuss the entropy for extremal quasiblack holes, a more subtle issue.

  10. Entropy, matter, and cosmology

    PubMed Central

    Prigogine, I.; Géhéniau, J.

    1986-01-01

    The role of irreversible processes corresponding to creation of matter in general relativity is investigated. The use of Landau-Lifshitz pseudotensors together with conformal (Minkowski) coordinates suggests that this creation took place in the early universe at the stage of the variation of the conformal factor. The entropy production in this creation process is calculated. It is shown that these dissipative processes lead to the possibility of cosmological models that start from empty conditions and gradually build up matter and entropy. Gravitational entropy takes a simple meaning as associated to the entropy that is necessary to produce matter. This leads to an extension of the third law of thermodynamics, as now the zero point of entropy becomes the space-time structure out of which matter is generated. The theory can be put into a convenient form using a supplementary “C” field in Einstein's field equations. The role of the C field is to express the coupling between gravitation and matter leading to irreversible entropy production. PMID:16593747

  11. Entropy and environmental mystery.

    PubMed

    Stamps, Arthur E

    2007-06-01

    Two studies are reported regarding the effects of entropy, lighting, and occlusion on impressions of mystery in physical environments. The theoretical context of this study was the "informational theory" of environmental preference, which, among other claims, holds that mystery can be measured by the extent to which people perceive a promise of more information if they move deeper into an environment. Entropy, in the context of this article, is visual diversity as measured using information theory. Mystery was measured by a semantic differential scale. The definition of mystery was left up to each individual participant. Entropy of occluded objects was used to obtain an objective, experimentally manipulatable and operational definition of "promise of more information." Exp. 1 had 12 stimuli and 15 participants. Exp. 2 had 12 stimuli and 16 participants. Entropy of occluded objects ranged from 0 to 6 bits. Entropy of occluded objects was used to measure the promise that there would be more information if one moved deeper into an environment. Overall, amount of light had the strongest effect on responses of mystery (r = -.63, darker was more mysterious), followed by occlusion (r = .26, occluding objects made a scene seem more mysterious), and by the promise of more information if one moved about in the scene (r = .13), the more entropy in occluded objects, the greater the impression of mystery). The theoretical contribution of this work is that a relationship between subjective impressions of mystery and an objective measure of "promise of more information" was found.

  12. Differential entropy and time

    NASA Astrophysics Data System (ADS)

    Garbaczewski, Piotr

    2005-12-01

    We give a detailed analysis of the Gibbs-type entropy notion and its dynamical behavior in case of time-dependent continuous probability distributions of varied origins: related to classical and quantum systems. The purpose-dependent usage of conditional Kullback-Leibler and Gibbs (Shannon) entropies is explained in case of non-equilibrium Smoluchowski processes. A very different temporal behavior of Gibbs and Kullback entropies is confronted. A specific conceptual niche is addressed, where quantum von Neumann, classical Kullback-Leibler and Gibbs entropies can be consistently introduced as information measures for the same physical system. If the dynamics of probability densities is driven by the Schrödinger picture wave-packet evolution, Gibbs-type and related Fisher information functionals appear to quantify nontrivial power transfer processes in the mean. This observation is found to extend to classical dissipative processes and supports the view that the Shannon entropy dynamics provides an insight into physically relevant non-equilibrium phenomena, which are inaccessible in terms of the Kullback-Leibler entropy and typically ignored in the literature.

  13. Chronic inflammation around painless partially erupted third molars.

    PubMed

    Laine, Mikael; Ventä, Irja; Hyrkäs, Tapio; Ma, Jian; Konttinen, Yrjö T

    2003-03-01

    We sought to assess the histologic host response in chronic, symptomless pericoronitis. Gingival mucosal (n = 20) and dental follicle (n = 20) samples were collected during extraction from patients with pericoronitis and clinically healthy control subjects. Antibodies-recognizing macrophages (CD68), natural killer cells (CD56), T cells (CD2), helper T cells (CD4), suppressor/cytotoxic T cells (CD8), and neutrophils (lactoferrin) were applied in a labelled streptavidin-biotin method by using a DAKO TechMate staining robot. Macrophage was the most numerous kind of cell in pericoronitis, but CD2+ T lymphocytes, with a normal CD4/CD8 ratio, were also increased (P < .01). Neutrophils were not increased and did not show signs of activation. Dental follicles did not contain increased numbers of inflammatory cells. This type of pericoronitis is a chronic/smoldering, rather than an acute/purulent, infection. Because of the chronic and often symptomless nature of pericoronitis, various long-term sequelae may result, which may lead to the need for extraction.

  14. Correlation of acute pericoronitis and the position of the mandibular third molar.

    PubMed

    Leone, S A; Edenfield, M J; Cohen, M E

    1986-09-01

    Acute pericoronitis is a painful, debilitating infection that is most commonly found among young adults with erupting mandibular third molars. Prophylactic removal of third molars to prevent this disease has been advocated, but this procedure requires an accurate description of the third molar at highest risk for this infection. Clinical and radiographic measurements were compared in 25 diseased subjects and 109 normal subjects. Of 10 variables significantly related to the presence of acute pericoronitis, stepwise discriminant analysis selected 4 variables that produced a canonical correlation coefficient of 0.71. In clinical terms, these variables described the tooth at highest risk for acute pericoronitis as a fully erupted, vertical mandibular third molar that is in contact with the adjacent second molar, at or above the occlusal plane, and partially encapsulated by soft or hard tissues. Prophylactic treatment of these third molars is highly recommended.

  15. Numerical estimation of the relative entropy of entanglement

    SciTech Connect

    Zinchenko, Yuriy; Friedland, Shmuel; Gour, Gilad

    2010-11-15

    We propose a practical algorithm for the calculation of the relative entropy of entanglement (REE), defined as the minimum relative entropy between a state and the set of states with positive partial transpose. Our algorithm is based on a practical semidefinite cutting plane approach. In low dimensions the implementation of the algorithm in matlab provides an estimation for the REE with an absolute error smaller than 10{sup -3}.

  16. Molar incisor hypomineralization, prevalence, and etiology.

    PubMed

    Allazzam, Sulaiman Mohammed; Alaki, Sumer Madani; El Meligy, Omar Abdel Sadek

    2014-01-01

    Aim. To evaluate the prevalence and possible etiological factors associated with molar incisor hypomineralization (MIH) among a group of children in Jeddah, Saudi Arabia. Methods. A group of 8-12-year-old children were recruited (n = 267) from the Pediatric Dental Clinics at the Faculty of Dentistry, King Abdulaziz University. Children had at least one first permanent molar (FPM), erupted or partially erupted. Demographic information, children's medical history, and pregnancy-related data were obtained. The crowns of the FPM and permanent incisors were examined for demarcated opacities, posteruptive breakdown (PEB), atypical restorations, and extracted FPMs. Children were considered to have MIH if one or more FPM with or without involvement of incisors met the diagnostic criteria. Results. MIH showed a prevalence of 8.6%. Demarcated opacities were the most common form. Maxillary central incisors were more affected than mandibular (P = 0.01). The condition was more prevalent in children with history of illnesses during the first four years of life including tonsillitis (P = 0.001), adenoiditis (P = 0.001), asthma (P = 0.001), fever (P = 0.014), and antibiotics intake (P = 0.001). Conclusions. The prevalence of MIH is significantly associated with childhood illnesses during the first four years of life including asthma, adenoid infections, tonsillitis, fever, and antibiotics intake.

  17. Molar Incisor Hypomineralization, Prevalence, and Etiology

    PubMed Central

    Allazzam, Sulaiman Mohammed; Alaki, Sumer Madani; El Meligy, Omar Abdel Sadek

    2014-01-01

    Aim. To evaluate the prevalence and possible etiological factors associated with molar incisor hypomineralization (MIH) among a group of children in Jeddah, Saudi Arabia. Methods. A group of 8-12-year-old children were recruited (n = 267) from the Pediatric Dental Clinics at the Faculty of Dentistry, King Abdulaziz University. Children had at least one first permanent molar (FPM), erupted or partially erupted. Demographic information, children's medical history, and pregnancy-related data were obtained. The crowns of the FPM and permanent incisors were examined for demarcated opacities, posteruptive breakdown (PEB), atypical restorations, and extracted FPMs. Children were considered to have MIH if one or more FPM with or without involvement of incisors met the diagnostic criteria. Results. MIH showed a prevalence of 8.6%. Demarcated opacities were the most common form. Maxillary central incisors were more affected than mandibular (P = 0.01). The condition was more prevalent in children with history of illnesses during the first four years of life including tonsillitis (P = 0.001), adenoiditis (P = 0.001), asthma (P = 0.001), fever (P = 0.014), and antibiotics intake (P = 0.001). Conclusions. The prevalence of MIH is significantly associated with childhood illnesses during the first four years of life including asthma, adenoid infections, tonsillitis, fever, and antibiotics intake. PMID:24949012

  18. Complications of third molar surgery.

    PubMed

    Bouloux, Gary F; Steed, Martin B; Perciaccante, Vincent J

    2007-02-01

    This article addresses the incidence of specific complications and, where possible, offers a preventive or management strategy. Injuries of the inferior alveolar and lingual nerves are significant issues that are discussed separately in this text. Surgical removal of third molars is often associated with postoperative pain, swelling, and trismus. Factors thought to influence the incidence of complications after third molar removal include age, gender, medical history, oral contraceptives, presence of pericoronitis, poor oral hygiene, smoking, type of impaction, relationship of third molar to the inferior alveolar nerve, surgical time, surgical technique, surgeon experience, use of perioperative antibiotics, use of topical antiseptics, use of intra-socket medications, and anesthetic technique. Complications that are discussed further include alveolar osteitis, postoperative infection, hemorrhage, oro-antral communication, damage to adjacent teeth, displaced teeth, and fractures.

  19. Hypomineralized Second Primary Molars as Predictor of Molar Incisor Hypomineralization.

    PubMed

    Negre-Barber, A; Montiel-Company, J M; Boronat-Catalá, M; Catalá-Pizarro, M; Almerich-Silla, J M

    2016-08-25

    Molar incisor hypomineralization (MIH) is a developmental defect of dental enamel that shares features with hypomineralized second primary molars (HSPM). Prior to permanent tooth eruption, second primary molars could have predictive value for permanent molar and incisor hypomineralization. To assess this possible relationship, a cross-sectional study was conducted in a sample of 414 children aged 8 and 9 years from the INMA cohort in Valencia (Spain). A calibrated examiner (linear-weighted Kappa 0.83) performed the intraoral examinations at the University of Valencia between November 2013 and 2014, applying the diagnostic criteria for MIH and HSPM adopted by the European Academy of Paediatric Dentistry. 100 children (24.2%) presented MIH and 60 (14.5%) presented HSPM. Co-occurrence of the two defects was observed in 11.1% of the children examined. The positive predictive value was 76.7% (63.9-86.6) and the negative predictive value 84.7% (80.6-88.3). The positive likelihood ratio (S/1-E) was 10.3 (5.9-17.9) and the negative likelihood ratio (1-S/E) 0.57 (0.47-0.68). The odds ratio was 18.2 (9.39-35.48). It was concluded that while the presence of HSPM can be considered a predictor of MIH, indicating the need for monitoring and control, the absence of this defect in primary dentition does not rule out the appearance of MIH.

  20. Molarization of Mandibular Second Premolar

    PubMed Central

    Singh Khinda, Vineet Inder; Kallar, Shiminder; Singh Brar, Gurlal

    2014-01-01

    ABSTRACT Macrodontia (megadontia, megalodontia, mac rodontism) is a rare shape anomaly that has been used to describe dental gigantism. Mandibular second premolars show an elevated variability of crown morphology, as are its eruptive potential and final position in the dental arch. To date, only eight cases of isolated macrodontia of second premolars have been reported in the literature. This case report presents clinical and radiographic findings of unusual and rare case of isolated unilateral molarization of left mandibular second premolar. How to cite this article: Mangla N, Khinda VIS, Kallar S, Brar GS. Molarization of Mandibular Second Premolar. Int J Clin Pediatr Dent 2014;7(2):137-139. PMID:25356014

  1. Extinction as discrimination: the molar view.

    PubMed

    Baum, William M

    2012-05-01

    The traditional molecular view of behavior explains extinction as the dissipation or inhibition of strength, formerly built up by contiguous reinforcement. In obstinate opposition to this explanation was the partial-reinforcement extinction effect: a partially reinforced response extinguishes more slowly than a continuously reinforced response. It suggests instead that extinction is discrimination. Four pigeons were exposed to daily sessions in which a variable period of food delivery, produced by pecking on a variable-interval schedule, was followed by extinction. The rate of food delivery was varied over a wide range across conditions. Varying the amount of food per delivery inversely with rate of delivery kept response rate from varying excessively. The results confirmed and extended the partial-reinforcement effect; persistence of pecking and time to extinction were inversely related to rate of obtaining food. The results support the molar view of extinction, not as loss of strength of a particular discrete response, but as a transition from one allocation of time among activities to another. Although molecular theories dismiss discrimination due to repeated training and extinction as an impurity or complication, repeated cycles of availability and privation are probably typical of the environment in which most vertebrate species evolved.

  2. On Entropy Trail

    NASA Astrophysics Data System (ADS)

    Farokhi, Saeed; Taghavi, Ray; Keshmiri, Shawn

    2015-11-01

    Stealth technology is developed for military aircraft to minimize their signatures. The primary attention was focused on radar signature, followed by the thermal and noise signatures of the vehicle. For radar evasion, advanced configuration designs, extensive use of carbon composites and radar-absorbing material, are developed. On thermal signature, mainly in the infra-red (IR) bandwidth, the solution was found in blended rectangular nozzles of high aspect ratio that are shielded from ground detectors. For noise, quiet and calm jets are integrated into vehicles with low-turbulence configuration design. However, these technologies are totally incapable of detecting new generation of revolutionary aircraft. These shall use all electric, distributed, propulsion system that are thermally transparent. In addition, composite skin and non-emitting sensors onboard the aircraft will lead to low signature. However, based on the second-law of thermodynamics, there is no air vehicle that can escape from leaving an entropy trail. Entropy is thus the only inevitable signature of any system, that once measured, can detect the source. By characterizing the entropy field based on its statistical properties, the source may be recognized, akin to face recognition technology. Direct measurement of entropy is cumbersome, however as a derived property, it can be easily measured. The measurement accuracy depends on the probe design and the sensors onboard. One novel air data sensor suite is introduced with promising potential to capture the entropy trail.

  3. Entropy, color, and color rendering.

    PubMed

    Price, Luke L A

    2012-12-01

    The Shannon entropy [Bell Syst. Tech J.27, 379 (1948)] of spectral distributions is applied to the problem of color rendering. With this novel approach, calculations for visual white entropy, spectral entropy, and color rendering are proposed, indices that are unreliant on the subjectivity inherent in reference spectra and color samples. The indices are tested against real lamp spectra, showing a simple and robust system for color rendering assessment. The discussion considers potential roles for white entropy in several areas of color theory and psychophysics and nonextensive entropy generalizations of the entropy indices in mathematical color spaces.

  4. Holographic entropy production

    NASA Astrophysics Data System (ADS)

    Tian, Yu; Wu, Xiao-Ning; Zhang, Hongbao

    2014-10-01

    The suspicion that gravity is holographic has been supported mainly by a variety of specific examples from string theory. In this paper, we propose that such a holography can actually be observed in the context of Einstein's gravity and at least a class of generalized gravitational theories, based on a definite holographic principle where neither is the bulk space-time required to be asymptotically AdS nor the boundary to be located at conformal infinity, echoing Wilson's formulation of quantum field theory. After showing the general equilibrium thermodynamics from the corresponding holographic dictionary, in particular, we provide a rather general proof of the equality between the entropy production on the boundary and the increase of black hole entropy in the bulk, which can be regarded as strong support to this holographic principle. The entropy production in the familiar holographic superconductors/superfluids is investigated as an important example, where the role played by the holographic renormalization is explained.

  5. Casimir entropy for magnetodielectrics.

    PubMed

    Klimchitskaya, G L; Korikov, C C

    2015-06-03

    We find the analytic expressions for the Casimir free energy, entropy and pressure at low temperature in the configuration of two parallel plates made of magnetodielectic material. The cases of constant and frequency-dependent dielectic permittivity and magnetic permeability of the plates are considered. Special attention is paid to the account of dc conductivity. It is shown that in the case of finite static dielectric permittivity and magnetic permeability the Nernst heat theorem for the Casimir entropy is satisfied. If the dc conductivity is taken into account, the Casimir entropy goes to a positive nonzero limit depending on the parameters of a system when the temperature vanishes, i.e. the Nernst theorem is violated. The experimental situation is also discussed.

  6. Clinical outcome of third molars in adults followed during 18 years.

    PubMed

    Ventä, Irja; Ylipaavalniemi, Pekka; Turtola, Lauri

    2004-02-01

    The aim of the present study was to follow the clinical changes in third molar status during an 18-year period in patients aged 20 to 38 years. The series consisted of 118 subjects (37 men and 81 women). In the beginning of the study, the mean age was 20.2 years (SD, +/-0.6 year), and at the end, it was 38.6 years (SD, +/-0.6 year). Panoramic radiographs were taken at baseline and at age 38. All of the subjects were clinically examined at baseline and at the end of the study. A portion of the subjects (n = 69) were also examined at age 32. Most of the initially unerupted third molars were removed during the follow-up period (73%, maxilla and mandible together). More than half of the initially partially erupted third molars were removed during the follow-up period (64%, maxilla and mandible together). The percentage of erupted third molars found in the mouth at age 38 increased significantly depending on the initial status. Of the initially unerupted, partially erupted, or erupted third molars, 10%, 33%, and 50%, respectively, were erupted at age 38 (maxilla and mandible together). Changes in the status of third molars continued from age 32 to age 38, although to a lesser extent (8%). The 3 third molars with advanced eruption were all maxillary teeth in men. Third molars undergo continuous clinical change on a reduced scale at least up to the age of 38 years.

  7. Sharp continuity bounds for entropy and conditional entropy

    NASA Astrophysics Data System (ADS)

    Chen, ZhiHua; Ma, ZhiHao; Nikoufar, Ismail; Fei, Shao-Ming

    2017-02-01

    The Renyi entropy plays an essential role in quantum information theory. We study the continuity estimation of the Renyi entropy. An inequality relating the Renyi entropy difference of two quantum states to their trace norm distance is derived. This inequality is shown to be tight in the sense that equality can be attained for every prescribed value of the trace norm distance. It includes the sharp Fannes inequality for von Neumann entropy as a special case.

  8. EEG entropy measures in anesthesia

    PubMed Central

    Liang, Zhenhu; Wang, Yinghua; Sun, Xue; Li, Duan; Voss, Logan J.; Sleigh, Jamie W.; Hagihira, Satoshi; Li, Xiaoli

    2015-01-01

    Highlights: ► Twelve entropy indices were systematically compared in monitoring depth of anesthesia and detecting burst suppression.► Renyi permutation entropy performed best in tracking EEG changes associated with different anesthesia states.► Approximate Entropy and Sample Entropy performed best in detecting burst suppression. Objective: Entropy algorithms have been widely used in analyzing EEG signals during anesthesia. However, a systematic comparison of these entropy algorithms in assessing anesthesia drugs' effect is lacking. In this study, we compare the capability of 12 entropy indices for monitoring depth of anesthesia (DoA) and detecting the burst suppression pattern (BSP), in anesthesia induced by GABAergic agents. Methods: Twelve indices were investigated, namely Response Entropy (RE) and State entropy (SE), three wavelet entropy (WE) measures [Shannon WE (SWE), Tsallis WE (TWE), and Renyi WE (RWE)], Hilbert-Huang spectral entropy (HHSE), approximate entropy (ApEn), sample entropy (SampEn), Fuzzy entropy, and three permutation entropy (PE) measures [Shannon PE (SPE), Tsallis PE (TPE) and Renyi PE (RPE)]. Two EEG data sets from sevoflurane-induced and isoflurane-induced anesthesia respectively were selected to assess the capability of each entropy index in DoA monitoring and BSP detection. To validate the effectiveness of these entropy algorithms, pharmacokinetic/pharmacodynamic (PK/PD) modeling and prediction probability (Pk) analysis were applied. The multifractal detrended fluctuation analysis (MDFA) as a non-entropy measure was compared. Results: All the entropy and MDFA indices could track the changes in EEG pattern during different anesthesia states. Three PE measures outperformed the other entropy indices, with less baseline variability, higher coefficient of determination (R2) and prediction probability, and RPE performed best; ApEn and SampEn discriminated BSP best. Additionally, these entropy measures showed an advantage in computation

  9. Replacement of missing molar teeth--a prosthodontic dilemma.

    PubMed

    Devlin, H

    1994-01-08

    In deciding whether to replace lost lower molar teeth with a denture or accept the status quo, the dentist is faced with a choice of equally unfavourable alternatives. Dentures tend to accumulate plaque, the main cause of periodontal destruction, but failure to provide a prosthesis may also disadvantage the patient. Whether or not the provision of a replacement partial denture following molar tooth extraction helps to maintain the periodontium of the remaining dentition is not known. Patients are also aware of the dilemma. Many surveys have shown that a large proportion of replacement lower, free-end saddle dentures are never worn. However, a failure to provide partial dentures may have many adverse effects, especially in young adults.

  10. Information entropy in cosmology.

    PubMed

    Hosoya, Akio; Buchert, Thomas; Morita, Masaaki

    2004-04-09

    The effective evolution of an inhomogeneous cosmological model may be described in terms of spatially averaged variables. We point out that in this context, quite naturally, a measure arises which is identical to a fluid model of the Kullback-Leibler relative information entropy, expressing the distinguishability of the local inhomogeneous mass density field from its spatial average on arbitrary compact domains. We discuss the time evolution of "effective information" and explore some implications. We conjecture that the information content of the Universe-measured by relative information entropy of a cosmological model containing dust matter-is increasing.

  11. Entropy and Enzyme Catalysis.

    PubMed

    Åqvist, Johan; Kazemi, Masoud; Isaksen, Geir Villy; Brandsdal, Bjørn Olav

    2017-02-21

    The role played by entropy for the enormous rate enhancement achieved by enzymes has been debated for many decades. There are, for example, several confirmed cases where the activation free energy is reduced by around 10 kcal/mol due to entropic effects, corresponding to a rate enhancement of ∼10(7) compared to the uncatalyzed reaction. However, despite substantial efforts from both the experimental and theoretical side, no real consensus has been reached regarding the origin of such large entropic contributions to enzyme catalysis. Another remarkable instance of entropic effects is found in enzymes that are adapted by evolution to work at low temperatures, near the freezing point of water. These cold-adapted enzymes invariably show a more negative entropy and a lower enthalpy of activation than their mesophilic orthologs, which counteracts the exponential damping of reaction rates at lower temperature. The structural origin of this universal phenomenon has, however, remained elusive. The basic problem with connecting macroscopic thermodynamic quantities, such as activation entropy and enthalpy derived from Arrhenius plots, to the 3D protein structure is that the underlying detailed (microscopic) energetics is essentially inaccessible to experiment. Moreover, attempts to calculate entropy contributions by computer simulations have mostly focused only on substrate entropies, which do not provide the full picture. We have recently devised a new approach for accessing thermodynamic activation parameters of both enzyme and solution reactions from computer simulations, which turns out to be very successful. This method is analogous to the experimental Arrhenius plots and directly evaluates the temperature dependence of calculated reaction free energy profiles. Hence, by extensive molecular dynamics simulations and calculations of up to thousands of independent free energy profiles, we are able to extract activation parameters with sufficient precision for making

  12. Calibrated entanglement entropy

    NASA Astrophysics Data System (ADS)

    Bakhmatov, I.; Deger, N. S.; Gutowski, J.; Colgáin, E. Ó.; Yavartanoo, H.

    2017-07-01

    The Ryu-Takayanagi prescription reduces the problem of calculating entanglement entropy in CFTs to the determination of minimal surfaces in a dual anti-de Sitter geometry. For 3D gravity theories and BTZ black holes, we identify the minimal surfaces as special Lagrangian cycles calibrated by the real part of the holomorphic one-form of a spacelike hypersurface. We show that (generalised) calibrations provide a unified way to determine holographic entanglement entropy from minimal surfaces, which is applicable to warped AdS3 geometries. We briefly discuss generalisations to higher dimensions.

  13. Heat capacty, relative enthalpy, and calorimetric entropy of silicate minerals: an empirical method of prediction.

    USGS Publications Warehouse

    Robinson, G.R.; Haas, J.L.

    1983-01-01

    Through the evaluation of experimental calorimetric data and estimates of the molar isobaric heat capacities, relative enthalpies and entropies of constituent oxides, a procedure for predicting the thermodynamic properties of silicates is developed. Estimates of the accuracy and precision of the technique and examples of its application are also presented. -J.A.Z.

  14. Entropy NOR: Early Functional Completeness in Entropy Networks

    NASA Astrophysics Data System (ADS)

    Jesse, Forrest Fabian; Miao, Zhenjiang; Li, Weidong

    2016-01-01

    Linking together two directional entropy disequilibriums, NOR functionality can be found. The entropy NOR gate presented is constructed of discrete observations and so is very small, emerging at the earliest stages of complexity. The gate is based on the axiom that an observer increases in entropy as it receives information from what it is observing.

  15. Vertical eruption patterns of impacted mandibular third molars after the mesialization of second molars using miniscrews.

    PubMed

    Baik, Un-Bong; Kook, Yoon-Ah; Bayome, Mohamed; Park, Je-Uk; Park, Jae Hyun

    2016-07-01

    To investigate (1) whether vertical eruption of impacted third molars improves after mesialization of second molars and (2) what factors affect the vertical eruption of impacted third molars when space caused by missing molars is successfully closed by mesialization of the second molar using miniscrews. The treatment group (Group 1) included 52 patients who had (1) missing mandibular first molars (ML-6) or missing deciduous mandibular second molars (ML-E), (2) initially impacted mandibular third molars, and (3) successful space closure of the edentulous area with orthodontics. Panoramic radiographs at start of treatment (T1) and at time of space closure (T2) were collected. The control group (Group 2) included 46 nonedentulous patients with impacted mandibular third molars without molar protraction treatment. Panoramic radiographs with similar T1/T2 treatment times were selected. Nine measurements were obtained regarding horizontal available space, vertical eruption, and third molar angulation. Third molars erupted vertically an average of 2.54 mm in Group 1 compared with 0.41 mm in Group 2. Age, gender, Nolla stage, and angle of the third molars did not show significant correlations with the vertical change of the impacted third molars, whereas the depth of third molar impaction and available space showed significant correlations. Impacted mandibular third molars vertically erupt as a result of uprighting with mesialization of the second molar, and vertical eruption is affected by the initial vertical location of impacted third molars and available space.

  16. Fluctuation theorem for partially masked nonequilibrium dynamics

    NASA Astrophysics Data System (ADS)

    Shiraishi, Naoto; Sagawa, Takahiro

    2015-01-01

    We establish a generalization of the fluctuation theorem for partially masked nonequilibrium dynamics. We introduce a partial entropy production with a subset of all possible transitions, and show that the partial entropy production satisfies the integral fluctuation theorem. Our result reveals the fundamental properties of a broad class of autonomous as well as nonautonomous nanomachines. In particular, our result gives a unified fluctuation theorem for both autonomous and nonautonomous Maxwell's demons, where mutual information plays a crucial role. Furthermore, we derive a fluctuation-dissipation theorem that relates nonequilibrium stationary current to two kinds of equilibrium fluctuations.

  17. Hypomineralized Second Primary Molars as Predictor of Molar Incisor Hypomineralization

    PubMed Central

    Negre-Barber, A.; Montiel-Company, J. M.; Boronat-Catalá, M.; Catalá-Pizarro, M.; Almerich-Silla, J. M.

    2016-01-01

    Molar incisor hypomineralization (MIH) is a developmental defect of dental enamel that shares features with hypomineralized second primary molars (HSPM). Prior to permanent tooth eruption, second primary molars could have predictive value for permanent molar and incisor hypomineralization. To assess this possible relationship, a cross-sectional study was conducted in a sample of 414 children aged 8 and 9 years from the INMA cohort in Valencia (Spain). A calibrated examiner (linear-weighted Kappa 0.83) performed the intraoral examinations at the University of Valencia between November 2013 and 2014, applying the diagnostic criteria for MIH and HSPM adopted by the European Academy of Paediatric Dentistry. 100 children (24.2%) presented MIH and 60 (14.5%) presented HSPM. Co-occurrence of the two defects was observed in 11.1% of the children examined. The positive predictive value was 76.7% (63.9–86.6) and the negative predictive value 84.7% (80.6–88.3). The positive likelihood ratio (S/1-E) was 10.3 (5.9–17.9) and the negative likelihood ratio (1-S/E) 0.57 (0.47–0.68). The odds ratio was 18.2 (9.39–35.48). It was concluded that while the presence of HSPM can be considered a predictor of MIH, indicating the need for monitoring and control, the absence of this defect in primary dentition does not rule out the appearance of MIH. PMID:27558479

  18. Differential molar heat capacities to test ideal solubility estimations.

    PubMed

    Neau, S H; Bhandarkar, S V; Hellmuth, E W

    1997-05-01

    Calculation of the ideal solubility of a crystalline solute in a liquid solvent requires knowledge of the difference in the molar heat capacity at constant pressure of the solid and the supercooled liquid forms of the solute, delta Cp. Since this parameter is not usually known, two assumptions have been used to simplify the expression. The first is that delta Cp can be considered equal to zero; the alternate assumption is that the molar entropy of fusion, delta Sf, is an estimate of delta Cp. Reports claiming the superiority of one assumption over the other, on the basis of calculations done using experimentally determined parameters, have appeared in the literature. The validity of the assumptions in predicting the ideal solubility of five structurally unrelated compounds of pharmaceutical interest, with melting points in the range 420 to 470 K, was evaluated in this study. Solid and liquid heat capacities of each compound near its melting point were determined using differential scanning calorimetry. Linear equations describing the heat capacities were extrapolated to the melting point to generate the differential molar heat capacity. Linear data were obtained for both crystal and liquid heat capacities of sample and test compounds. For each sample, ideal solubility at 298 K was calculated and compared to the two estimates generated using literature equations based on the differential molar heat capacity assumptions. For the compounds studied, delta Cp was not negligible and was closer to delta Sf than to zero. However, neither of the two assumptions was valid for accurately estimating the ideal solubility as given by the full equation.

  19. Entropy of the Universe

    NASA Astrophysics Data System (ADS)

    Sato, Humitaka

    2010-06-01

    Charles Darwin's calculation of a life of Earth had ignited Kelvin's insight on a life of Sun, which had eventually inherited to the physical study of stellar structure and energy source. Nuclear energy had secured a longevity of the universe and the goal of the cosmic evolution has been secured by the entropy of black holes.

  20. Rescaling Temperature and Entropy

    ERIC Educational Resources Information Center

    Olmsted, John, III

    2010-01-01

    Temperature and entropy traditionally are expressed in units of kelvin and joule/kelvin. These units obscure some important aspects of the natures of these thermodynamic quantities. Defining a rescaled temperature using the Boltzmann constant, T' = k[subscript B]T, expresses temperature in energy units, thereby emphasizing the close relationship…

  1. Maximum Entropies Copulas

    NASA Astrophysics Data System (ADS)

    Pougaza, Doriano-Boris; Mohammad-Djafari, Ali

    2011-03-01

    New families of copulas are obtained in a two-step process: first considering the inverse problem which consists of finding a joint distribution from its given marginals as the constrained maximization of some entropies (Shannon, Rényi, Burg, Tsallis-Havrda-Charvát), and then using Sklar's theorem, to define the corresponding copula.

  2. Optimized Kernel Entropy Components.

    PubMed

    Izquierdo-Verdiguier, Emma; Laparra, Valero; Jenssen, Robert; Gomez-Chova, Luis; Camps-Valls, Gustau

    2016-02-25

    This brief addresses two main issues of the standard kernel entropy component analysis (KECA) algorithm: the optimization of the kernel decomposition and the optimization of the Gaussian kernel parameter. KECA roughly reduces to a sorting of the importance of kernel eigenvectors by entropy instead of variance, as in the kernel principal components analysis. In this brief, we propose an extension of the KECA method, named optimized KECA (OKECA), that directly extracts the optimal features retaining most of the data entropy by means of compacting the information in very few features (often in just one or two). The proposed method produces features which have higher expressive power. In particular, it is based on the independent component analysis framework, and introduces an extra rotation to the eigen decomposition, which is optimized via gradient-ascent search. This maximum entropy preservation suggests that OKECA features are more efficient than KECA features for density estimation. In addition, a critical issue in both the methods is the selection of the kernel parameter, since it critically affects the resulting performance. Here, we analyze the most common kernel length-scale selection criteria. The results of both the methods are illustrated in different synthetic and real problems. Results show that OKECA returns projections with more expressive power than KECA, the most successful rule for estimating the kernel parameter is based on maximum likelihood, and OKECA is more robust to the selection of the length-scale parameter in kernel density estimation.

  3. Rescaling Temperature and Entropy

    ERIC Educational Resources Information Center

    Olmsted, John, III

    2010-01-01

    Temperature and entropy traditionally are expressed in units of kelvin and joule/kelvin. These units obscure some important aspects of the natures of these thermodynamic quantities. Defining a rescaled temperature using the Boltzmann constant, T' = k[subscript B]T, expresses temperature in energy units, thereby emphasizing the close relationship…

  4. Entropy and cosmology.

    NASA Astrophysics Data System (ADS)

    Zucker, M. H.

    This paper is a critical analysis and reassessment of entropic functioning as it applies to the question of whether the ultimate fate of the universe will be determined in the future to be "open" (expanding forever to expire in a big chill), "closed" (collapsing to a big crunch), or "flat" (balanced forever between the two). The second law of thermodynamics declares that entropy can only increase and that this principle extends, inevitably, to the universe as a whole. This paper takes the position that this extension is an unwarranted projection based neither on experience nonfact - an extrapolation that ignores the powerful effect of a gravitational force acting within a closed system. Since it was originally presented by Clausius, the thermodynamic concept of entropy has been redefined in terms of "order" and "disorder" - order being equated with a low degree of entropy and disorder with a high degree. This revised terminology more subjective than precise, has generated considerable confusion in cosmology in several critical instances. For example - the chaotic fireball of the big bang, interpreted by Stephen Hawking as a state of disorder (high entropy), is infinitely hot and, thermally, represents zero entropy (order). Hawking, apparently focusing on the disorderly "chaotic" aspect, equated it with a high degree of entropy - overlooking the fact that the universe is a thermodynamic system and that the key factor in evaluating the big-bang phenomenon is the infinitely high temperature at the early universe, which can only be equated with zero entropy. This analysis resolves this confusion and reestablishes entropy as a cosmological function integrally linked to temperature. The paper goes on to show that, while all subsystems contained within the universe require external sources of energization to have their temperatures raised, this requirement does not apply to the universe as a whole. The universe is the only system that, by itself can raise its own

  5. Mandibular lip bumper for molar torque control.

    PubMed

    Celentano, Giuseppe; Longobardi, Annalisa; Cannavale, Rosangela; Perillo, Letizia

    2011-01-01

    Treatment effects of lip bumpers alone include flaring of the mandibular incisors, distalization and uprighting of the mandibular first molars, and buccal expansion of the canines, premolars, and molar. Lip forces are transmitted through this appliance onto the molars. Moreover the lip bumper is able to derotate, expand or constrict, upright and reinforce the anchorage whereas torque control is lacking. Aim of this paper is the presentation of a new type of lip bumper that allows the molar torque control.

  6. Impacted lower third molars and distal caries in the mandibular second molar. Is prophylactic removal of lower third molars justified?

    PubMed Central

    Marques, José; Montserrat-Bosch, Marta; Vilchez-Pérez, Miguel-Angel; Valmaseda-Castellón, Eduard; Gay-Escoda, Cosme

    2017-01-01

    Background The objective of this study was to evaluate the association between the presence of mandibular third molars and the occurrence of carious lesions in the distal aspect of the mandibular second molar. Material and Methods A retrospective cohort study comprising 327 lower third molars extracted in the Oral Surgery and Implantology Master’s Degree program of the School of Dentistry of the University of Barcelona (Barcelona, Spain) was carried out. A descriptive and bivariate analysis was made. The diagnosis of caries in the second molar and the position of the mandibular third molar were evaluated through panoramic radiographies. Results The sample included 203 patients, 94 males (46.3%) and 109 females (53.7%), with a mean age of 26,8 years and 327 lower third molars. The prevalence of second molar distal caries was 25.4% (95% CI= 20.6% to 30.2%). This pathology was significantly more frequent when the third molar was in a horizontal position (27.7%), when the contact point was at (45,8%) or below (47.0%) the cementoenamel junction (CEJ), and when the distal CEJ of the mandibular second molar and the mesial CEJ of the third molar was 7 to 12 mm apart. Conclusions Horizontal lower third molars with contact points at or below the CEJ are more likely to produce distal caries in the mandibular second molars. Due to the high prevalence of this pathology (20.6% to 30.2%), a prophylactic removal of lower third molars with the above-mentioned features might be advisable. Key words:Second molar, caries, third molar, prophylactic removal. PMID:28638558

  7. An investigation of combustion and entropy noise

    NASA Technical Reports Server (NTRS)

    Strahle, W. C.

    1977-01-01

    The relative importance of entropy and direct combustion noise in turbopropulsion systems and the parameters upon which these noise sources depend were studied. Theory and experiment were employed to determine that at least with the apparatus used here, entropy noise can dominate combustion noise if there is a sufficient pressure gradient terminating the combustor. Measurements included combustor interior fluctuating pressure, near and far field fluctuating pressure, and combustor exit plane fluctuating temperatures, as well as mean pressures and temperatures. Analysis techniques included spectral, cross-correlation, cross power spectra, and ordinary and partial coherence analysis. Also conducted were combustor liner modification experiments to investigate the origin of the frequency content of combustion noise. Techniques were developed to extract nonpropagational pseudo-sound and the heat release fluctuation spectra from the data.

  8. Fracture behavior of human molars.

    PubMed

    Keown, Amanda J; Lee, James J-W; Bush, Mark B

    2012-12-01

    Despite the durability of human teeth, which are able to withstand repeated loading while maintaining form and function, they are still susceptible to fracture. We focus here on longitudinal fracture in molar teeth-channel-like cracks that run along the enamel sidewall of the tooth between the gum line (cemento-enamel junction-CEJ) and the occlusal surface. Such fractures can often be painful and necessitate costly restorative work. The following study describes fracture experiments made on molar teeth of humans in which the molars are placed under axial compressive load using a hard indenting plate in order to induce longitudinal cracks in the enamel. Observed damage modes include fractures originating in the occlusal region ('radial-median cracks') and fractures emanating from the margin of the enamel in the region of the CEJ ('margin cracks'), as well as 'spalling' of enamel (the linking of longitudinal cracks). The loading conditions that govern fracture behavior in enamel are reported and observations made of the evolution of fracture as the load is increased. Relatively low loads were required to induce observable crack initiation-approximately 100 N for radial-median cracks and 200 N for margin cracks-both of which are less than the reported maximum biting force on a single molar tooth of several hundred Newtons. Unstable crack growth was observed to take place soon after and occurred at loads lower than those calculated by the current fracture models. Multiple cracks were observed on a single cusp, their interactions influencing crack growth behavior. The majority of the teeth tested in this study were noted to exhibit margin cracks prior to compression testing, which were apparently formed during the functional lifetime of the tooth. Such teeth were still able to withstand additional loading prior to catastrophic fracture, highlighting the remarkable damage containment capabilities of the natural tooth structure.

  9. Molar versus as a paradigm clash.

    PubMed Central

    Baum, W M

    2001-01-01

    The molar view of behavior arose in response to the demonstrated inadequacy of explanations based on contiguity. Although Dinsmoor's (2001) modifications to two-factor theory render it irrefutable, a more basic criticism arises when we see that the molar and molecular views differ paradigmatically. The molar view has proven more productive. PMID:11453623

  10. THE MOLAR EXTINCTION OF RHODOPSIN

    PubMed Central

    Wald, George; Brown, Paul K.

    1953-01-01

    The molar extinction of rhodopsin is 40,600 cm.2 per mole equivalent of retinene; i.e., this is the extinction of a solution of rhodopsin which is produced by, or yields on bleaching, a molar solution of retinene. The molar extinctions of all-trans retinene and all-trans retinene oxime have also been determined in ethyl alcohol and aqueous digitonin solutions. On the assumption that each chromophoric group of rhodopsin is made from a single molecule of retinene, it is concluded that the primary photochemical conversion of rhodopsin to lumi-rhodopsin has a quantum efficiency of 1; though the over-all bleaching of rhodopsin in solution to retinene and opsin may have a quantum efficiency as low as one-half. On bleaching cattle rhodopsin, about two sulfhydryl groups appear for each molecule of retinene liberated. In frog rhodopsin the —SH:retinene ratio appears to be higher, 5:2 or perhaps even 3:1. Some of this sulfhydryl appears to have been engaged in binding retinene to opsin; some may have been exposed as the result of changes in opsin which accompany bleaching, comparable with protein denaturation. PMID:13109155

  11. Third molar complications requiring hospitalization.

    PubMed

    Kunkel, Martin; Morbach, Thomas; Kleis, Wilfried; Wagner, Wilfried

    2006-09-01

    The aim of this study was to describe demographic and clinical patterns of subjects hospitalized with complications associated with third molars (M3). The investigation was designed as a prospective cohort study composed of subjects admitted to hospital for management of M3-associated complications. The predictor variable was "clinical status of the M3" defined as (A) prophylactic M3 removal, (B) nonelective M3 removal, or (C) M3 present at the time of admission. Outcome variables were infection parameters, treatment costs, length of hospital stay, and days of disability. Postoperative complications (A and B) were compared to complications based on pericoronitis (C). Complications due to prophylactic removal (A) were compared to those arising from pericoronitis or from the removal of symptomatic teeth (B and C). From January 2003 to December 2004, 45 deep space infections, 6 mandibular fractures, 2 lingual nerve injuries, 1 parapharyngeal tooth luxation, and 1 osteomyelitis were noticed. Fifteen complications resulted from prophylactic surgery (A), 25 from nonelective removal (B), and 15 from pericoronitis (C). Direct treatment costs were 147,000 euro (A: 42,000 euro; B: 74,000 euro; C: 31,000 euro). In 10 of the 15 patients of group C, deep space involvement resulted immediately from the first episode of pericoronitis. Neither clinical markers of infection nor economic parameters showed significant differences between the groups. Within the catchment area of our institution, the majority of third molar-related hospitalizations resulted from diseased third molars or their removal.

  12. Diffusive mixing and Tsallis entropy

    DOE PAGES

    O'Malley, Daniel; Vesselinov, Velimir V.; Cushman, John H.

    2015-04-29

    Brownian motion, the classical diffusive process, maximizes the Boltzmann-Gibbs entropy. The Tsallis q-entropy, which is non-additive, was developed as an alternative to the classical entropy for systems which are non-ergodic. A generalization of Brownian motion is provided that maximizes the Tsallis entropy rather than the Boltzmann-Gibbs entropy. This process is driven by a Brownian measure with a random diffusion coefficient. In addition, the distribution of this coefficient is derived as a function of q for 1 < q < 3. Applications to transport in porous media are considered.

  13. The different paths to entropy

    NASA Astrophysics Data System (ADS)

    Benguigui, L.

    2013-03-01

    In order to understand how the complex concept of entropy emerged, we propose a trip into the past, reviewing the works of Clausius, Boltzmann, Gibbs and Planck. In particular, since Gibbs's work is not very well known we present a detailed analysis, recalling the three definitions of entropy that Gibbs gives. The introduction of entropy in quantum mechanics gives in a compact form all the classical definitions of entropy. Perhaps one of the most important aspects of entropy is to see it as a thermodynamic potential like the others proposed by Callen. The calculation of fluctuations in thermodynamic quantities is thus naturally related to entropy. We close with some remarks on entropy and irreversibility.

  14. Negative Entropy of Life

    NASA Astrophysics Data System (ADS)

    Goradia, Shantilal

    2015-10-01

    We modify Newtonian gravity to probabilistic quantum mechanical gravity to derive strong coupling. If this approach is valid, we should be able to extend it to the physical body (life) as follows. Using Boltzmann equation, we get the entropy of the universe (137) as if its reciprocal, the fine structure constant (ALPHA), is the hidden candidate representing the negative entropy of the universe which is indicative of the binary information as its basis (http://www.arXiv.org/pdf/physics0210040v5). Since ALPHA relates to cosmology, it must relate to molecular biology too, with the binary system as the fundamental source of information for the nucleotides of the DNA as implicit in the book by the author: ``Quantum Consciousness - The Road to Reality.'' We debate claims of anthropic principle based on the negligible variation of ALPHA and throw light on thermodynamics. We question constancy of G in multiple ways.

  15. Entropy and information optics

    NASA Astrophysics Data System (ADS)

    Yu, Francis T. S.

    2000-03-01

    In this paper we shall begin our discussion with the relationship between optics and humans, in which we see that light has indeed provided us with a very valuable source of information. A general optical communication concept is discussed, in which we see that a picture is indeed worth more than a thousand words. Based on Shannon's information theory, one can show that entropy and information can be simply traded. One of the most intriguing laws of thermodynamics must be the second law, in which we have found that there exists a profound relationship between the physical entropy and information. Without this relationship, information theory would be totally useless in physical science. By applying this relationship, Maxwell and diffraction-limited demons are discussed. And finally, samples of information optics are provided.

  16. Entropy-stabilized oxides

    PubMed Central

    Rost, Christina M.; Sachet, Edward; Borman, Trent; Moballegh, Ali; Dickey, Elizabeth C.; Hou, Dong; Jones, Jacob L.; Curtarolo, Stefano; Maria, Jon-Paul

    2015-01-01

    Configurational disorder can be compositionally engineered into mixed oxide by populating a single sublattice with many distinct cations. The formulations promote novel and entropy-stabilized forms of crystalline matter where metal cations are incorporated in new ways. Here, through rigorous experiments, a simple thermodynamic model, and a five-component oxide formulation, we demonstrate beyond reasonable doubt that entropy predominates the thermodynamic landscape, and drives a reversible solid-state transformation between a multiphase and single-phase state. In the latter, cation distributions are proven to be random and homogeneous. The findings validate the hypothesis that deliberate configurational disorder provides an orthogonal strategy to imagine and discover new phases of crystalline matter and untapped opportunities for property engineering. PMID:26415623

  17. Avoiding the entropy trap

    SciTech Connect

    Weinberg, A.M.

    1982-10-01

    Utopians who use entropy to warn of a vast deterioration of energy and mineral resources seek a self-fulfilling prophesy when they work to deny society access to new energy sources, particularly nuclear power. While theoretically correct, entropy is not the relevant factor for the rest of this century. The more extreme entropists call for a return to an eotechnic society based on decentralized, renewable energy technologies, which rests on the assumptions of a loss in Gibbs Free Energy, a mineral depletion that will lead to OPEC-like manipulation, and a current technology that is destroying the environment. The author challenges these assumptions and calls for an exorcism of public fears over reactor accidents. He foresees a resurgence in public confidence in nuclear power by 1990 that will resolve Western dependence on foreign oil. (DCK)

  18. Relative Entropy Credibility Theory

    NASA Astrophysics Data System (ADS)

    Fernández-Durán, Juan José; Gregorio-Domínguez, María Mercedes

    2004-11-01

    Consider a portfolio of personal motor insurance policies in which, for each policyholder in the portfolio, we want to assign a credibility factor at the end of each policy period that reflects the claim experience of the policyholder compared with the claim experience of the entire portfolio. In this paper we present the calculation of credibility factors based on the concept of relative entropy between the claim size distribution of the entire portfolio and the claim size distribution of the policyholder.

  19. Quantum and Ecosystem Entropies

    NASA Astrophysics Data System (ADS)

    Kirwan, A. D.

    2008-06-01

    Ecosystems and quantum gases share a number of superficial similarities including enormous numbers of interacting elements and the fundamental role of energy in such interactions. A theory for the synthesis of data and prediction of new phenomena is well established in quantum statistical mechanics. The premise of this paper is that the reason a comparable unifying theory has not emerged in ecology is that a proper role for entropy has yet to be assigned. To this end, a phase space entropy model of ecosystems is developed. Specification of an ecosystem phase space cell size based on microbial mass, length, and time scales gives an ecosystem uncertainty parameter only about three orders of magnitude larger than Planck’s constant. Ecosystem equilibria is specified by conservation of biomass and total metabolic energy, along with the principle of maximum entropy at equilibria. Both Bose - Einstein and Fermi - Dirac equilibrium conditions arise in ecosystems applications. The paper concludes with a discussion of some broader aspects of an ecosystem phase space.

  20. Entropy meters and the entropy of non-extensive systems

    PubMed Central

    Lieb, Elliott H.; Yngvason, Jakob

    2014-01-01

    In our derivation of the second law of thermodynamics from the relation of adiabatic accessibility of equilibrium states, we stressed the importance of being able to scale a system's size without changing its intrinsic properties. This leaves open the question of defining the entropy of macroscopic, but unscalable systems, such as gravitating bodies or systems where surface effects are important. We show here how the problem can be overcome, in principle, with the aid of an ‘entropy meter’. An entropy meter can also be used to determine entropy functions for non-equilibrium states and mesoscopic systems. PMID:25002830

  1. Quantum information entropy for one-dimensional system undergoing quantum phase transition

    NASA Astrophysics Data System (ADS)

    Xu-Dong, Song; Shi-Hai, Dong; Yu, Zhang

    2016-05-01

    Calculations of the quantum information entropy have been extended to a non-analytically solvable situation. Specifically, we have investigated the information entropy for a one-dimensional system with a schematic “Landau” potential in a numerical way. Particularly, it is found that the phase transitional behavior of the system can be well expressed by the evolution of quantum information entropy. The calculated results also indicate that the position entropy Sx and the momentum entropy Sp at the critical point of phase transition may vary with the mass parameter M but their sum remains as a constant independent of M for a given excited state. In addition, the entropy uncertainty relation is proven to be robust during the whole process of the phase transition. Project supported by the National Natural Science Foundation of China (Grant No. 11375005) and partially by 20150964-SIP-IPN, Mexico.

  2. Nonequilibrium Entropy in a Shock

    DOE PAGES

    Margolin, Len G.

    2017-07-19

    In a classic paper, Morduchow and Libby use an analytic solution for the profile of a Navier–Stokes shock to show that the equilibrium thermodynamic entropy has a maximum inside the shock. There is no general nonequilibrium thermodynamic formulation of entropy; the extension of equilibrium theory to nonequililbrium processes is usually made through the assumption of local thermodynamic equilibrium (LTE). However, gas kinetic theory provides a perfectly general formulation of a nonequilibrium entropy in terms of the probability distribution function (PDF) solutions of the Boltzmann equation. In this paper I will evaluate the Boltzmann entropy for the PDF that underlies themore » Navier–Stokes equations and also for the PDF of the Mott–Smith shock solution. I will show that both monotonically increase in the shock. As a result, I will propose a new nonequilibrium thermodynamic entropy and show that it is also monotone and closely approximates the Boltzmann entropy.« less

  3. Quantum chaos: An entropy approach

    NASA Astrophysics Data System (ADS)

    Sl/omczyński, Wojciech; Życzkowski, Karol

    1994-11-01

    A new definition of the entropy of a given dynamical system and of an instrument describing the measurement process is proposed within the operational approach to quantum mechanics. It generalizes other definitions of entropy, in both the classical and quantum cases. The Kolmogorov-Sinai (KS) entropy is obtained for a classical system and the sharp measurement instrument. For a quantum system and a coherent states instrument, a new quantity, coherent states entropy, is defined. It may be used to measure chaos in quantum mechanics. The following correspondence principle is proved: the upper limit of the coherent states entropy of a quantum map as ℏ→0 is less than or equal to the KS-entropy of the corresponding classical map. ``Chaos umpire sits, And by decision more imbroils the fray By which he reigns: next him high arbiter Chance governs all.'' John Milton, Paradise Lost, Book II

  4. Trading coherence and entropy by a quantum Maxwell demon

    NASA Astrophysics Data System (ADS)

    Lebedev, A. V.; Oehri, D.; Lesovik, G. B.; Blatter, G.

    2016-11-01

    The second law of thermodynamics states that the entropy of a closed system is nondecreasing. Discussing the second law in the quantum world poses different challenges and provides different opportunities, involving fundamental quantum-information-theoretic questions and interesting quantum-engineered devices. In quantum mechanics, systems with an evolution described by a so-called unital quantum channel evolve with a nondecreasing entropy. Here, we seek the opposite, a system described by a nonunital and, furthermore, energy-conserving channel that describes a system whose entropy decreases with time. We propose a setup involving a mesoscopic four-lead scatterer augmented by a microenvironment in the form of a spin that realizes this goal. Within this nonunital and energy-conserving quantum channel, the microenvironment acts with two noncommuting operations on the system in an autonomous way. We find that the process corresponds to a partial exchange or swap between the system and environment quantum states, with the system's entropy decreasing if the environment's state is more pure. This entropy-decreasing process is naturally expressed through the action of a quantum Maxwell demon and we propose a quantum-thermodynamic engine with four qubits that extracts work from a single heat reservoir when provided with a reservoir of pure qubits. The special feature of this engine, which derives from the energy conservation in the nonunital quantum channel, is its separation into two cycles, a working cycle and an entropy cycle, allowing us to run this engine with no local waste heat.

  5. Approximate entropy and support vector machines for electroencephalogram signal classification

    PubMed Central

    Zhang, Zhen; Zhou, Yi; Chen, Ziyi; Tian, Xianghua; Du, Shouhong; Huang, Ruimei

    2013-01-01

    The automatic detection and identification of electroencephalogram waves play an important role in the prediction, diagnosis and treatment of epileptic seizures. In this study, a nonlinear dynamics index–approximate entropy and a support vector machine that has strong generalization ability were applied to classify electroencephalogram signals at epileptic interictal and ictal periods. Our aim was to verify whether approximate entropy waves can be effectively applied to the automatic real-time detection of epilepsy in the electroencephalogram, and to explore its generalization ability as a classifier trained using a nonlinear dynamics index. Four patients presenting with partial epileptic seizures were included in this study. They were all diagnosed with neocortex localized epilepsy and epileptic foci were clearly observed by electroencephalogram. The electroencephalogram data form the four involved patients were segmented and the characteristic values of each segment, that is, the approximate entropy, were extracted. The support vector machine classifier was constructed with the approximate entropy extracted from one epileptic case, and then electroencephalogram waves of the other three cases were classified, reaching a 93.33% accuracy rate. Our findings suggest that the use of approximate entropy allows the automatic real-time detection of electroencephalogram data in epileptic cases. The combination of approximate entropy and support vector machines shows good generalization ability for the classification of electroencephalogram signals for epilepsy. PMID:25206493

  6. Entropy of electromyography time series

    NASA Astrophysics Data System (ADS)

    Kaufman, Miron; Zurcher, Ulrich; Sung, Paul S.

    2007-12-01

    A nonlinear analysis based on Renyi entropy is applied to electromyography (EMG) time series from back muscles. The time dependence of the entropy of the EMG signal exhibits a crossover from a subdiffusive regime at short times to a plateau at longer times. We argue that this behavior characterizes complex biological systems. The plateau value of the entropy can be used to differentiate between healthy and low back pain individuals.

  7. Unerupted mandibular third molars: symptoms, associated pathologies, and indications for removal in a Turkish population.

    PubMed

    Doğan, Necdet; Orhan, Kaan; Günaydin, Yilmaz; Köymen, Ramazan; Okçu, Kemal; Uçok, Ozlem

    2007-09-01

    To analyze the occurrence of symptoms of unerupted mandibular third molars, to investigate associated pathologies, and to determine indications for removal of unerupted mandibular third molars in a Turkish population. A retrospective study was performed by reviewing 832 patients referred to Gulhane Military Medical Academy Dentistry Center for evaluation of their mandibular third molars. The patients were clinically examined, and unerupted and partially erupted mandibular third molars were determined from radiographs. The symptoms and pathologies associated with these teeth were analyzed. The indications for removal were classified into 10 groups. Two-thirds of the patients were between 20 and 29 years of age. Of the 832 unerupted mandibular third molars found, 557 (66.9%) teeth were partially erupted and 275 (33.1%) were completely unerupted. A total of 521 (62.6%) of all unerupted third molars had no symptoms, while 311 (37.4%) were associated with symptoms. The most frequent complaints of the patients were pain and swelling. Pericoronitis was observed as the most frequent pathology, in 142 patients. Of 832 unerupted mandibular third molars, 582 (69.9%) had complete root formation, 177 (21.2%) had two-thirds root formation, and 73 (8.9%) had one-third root formation. Patients between 20 and 29 years of age had the highest prevalence of unerupted mandibular third molars (69.3%). However, this figure decreased with increasing age. Partially erupted teeth (n = 228) caused the occurrence of symptoms more than completely erupted teeth (n = 83) in a Turkish population.

  8. Entanglement Entropy of Black Holes

    NASA Astrophysics Data System (ADS)

    Solodukhin, Sergey N.

    2011-12-01

    The entanglement entropy is a fundamental quantity, which characterizes the correlations between sub-systems in a larger quantum-mechanical system. For two sub-systems separated by a surface the entanglement entropy is proportional to the area of the surface and depends on the UV cutoff, which regulates the short-distance correlations. The geometrical nature of entanglement-entropy calculation is particularly intriguing when applied to black holes when the entangling surface is the black-hole horizon. I review a variety of aspects of this calculation: the useful mathematical tools such as the geometry of spaces with conical singularities and the heat kernel method, the UV divergences in the entropy and their renormalization, the logarithmic terms in the entanglement entropy in four and six dimensions and their relation to the conformal anomalies. The focus in the review is on the systematic use of the conical singularity method. The relations to other known approaches such as ’t Hooft’s brick-wall model and the Euclidean path integral in the optical metric are discussed in detail. The puzzling behavior of the entanglement entropy due to fields, which non-minimally couple to gravity, is emphasized. The holographic description of the entanglement entropy of the blackhole horizon is illustrated on the two- and four-dimensional examples. Finally, I examine the possibility to interpret the Bekenstein-Hawking entropy entirely as the entanglement entropy.

  9. Entropy Generation in Regenerative Systems

    NASA Technical Reports Server (NTRS)

    Kittel, Peter

    1995-01-01

    Heat exchange to the oscillating flows in regenerative coolers generates entropy. These flows are characterized by oscillating mass flows and oscillating temperatures. Heat is transferred between the flow and heat exchangers and regenerators. In the former case, there is a steady temperature difference between the flow and the heat exchangers. In the latter case, there is no mean temperature difference. In this paper a mathematical model of the entropy generated is developed for both cases. Estimates of the entropy generated by this process are given for oscillating flows in heat exchangers and in regenerators. The practical significance of this entropy is also discussed.

  10. Entanglement entropy on fuzzy spaces

    SciTech Connect

    Dou, Djamel; Ydri, Badis

    2006-08-15

    We study the entanglement entropy of a scalar field in 2+1 spacetime where space is modeled by a fuzzy sphere and a fuzzy disc. In both models we evaluate numerically the resulting entropies and find that they are proportional to the number of boundary degrees of freedom. In the Moyal plane limit of the fuzzy disc the entanglement entropy per unite area (length) diverges if the ignored region is of infinite size. The divergence is (interpreted) of IR-UV mixing origin. In general we expect the entanglement entropy per unite area to be finite on a noncommutative space if the ignored region is of finite size.

  11. Automorphic Black Hole Entropy

    NASA Astrophysics Data System (ADS)

    Schimmrigk, Rolf

    2013-09-01

    Over the past few years the understanding of the microscopic theory of black hole entropy has made important conceptual progress by recognizing that the degeneracies are encoded in partition functions which are determined by higher rank automorphic representations, in particular in the context of Siegel modular forms of genus two. In this review, some of the elements of this framework are highlighted. One of the surprising aspects is that the Siegel forms that have appeared in the entropic context are geometric in origin, arising from weight two cusp forms, hence from elliptic curves.

  12. Prevalence and Pattern of Third Molar Impaction

    PubMed Central

    Al-Anqudi, Samira M.; Al-Sudairy, Salim; Al-Hosni, Ahmed; Al-Maniri, Abdullah

    2014-01-01

    Objectives: The aim of this retrospective study was to investigate the prevalence and pattern of third molar impaction in patients between 19–26 years old attending Sultan Qaboos University Hospital (SQUH) in Muscat, Oman. Methods: The study reviewed 1,000 orthopantomograms (OPGs) of patients attending the Oral Health Department of SQUH between October 2010 and April 2011. Patients were evaluated to determine the prevalence of third molar impaction, angulation, level of eruption and associated pathological conditions. Results: Of the study population, 543 (54.3%) OPGs showed at least one impacted third molar. The total number of impacted molars was 1,128. The most common number of impacted third molars was two (41%). The most common angulation of impaction in the mandible was the mesioangular (35%) and the most common level of impaction in the mandible was level A. Of the 388 bilateral occurrences of impacted third molars, 377 were in the mandible. There was no significant difference in the frequency of impaction between the right and left sides of both jaws. Pathological conditions associated with impacted lower third molars were found in 18%, of which 14% were associated with a radiographic radiolucency of more than 2.5 mm, and 4% of impacted lower third molars were associated with dental caries. Conclusion: This study found that more than half of Omani adult patients ranging in age from 19–26 years had at least one impacted third molar. PMID:25097776

  13. Revolution vs status quo? Non-intervention strategy of asymptomatic third molars causes harm.

    PubMed

    Toedtling, V; Yates, J M

    2015-07-10

    The Faculty of Dental Surgery of the Royal College of Surgeons of England has prompted the National Institute for Health and Care Excellence to urgently re-assess the TA1 guidance on extractions of wisdom teeth and highlighted required amendments to the present version in light of published evidence concerning the harm caused by wisdom tooth retention. This article seeks to address the recent concerns relating the increasing frequency of distal-cervical caries in lower second molar teeth when associated with asymptomatic partially erupted mesial or horizontal impacted mandibular third molars. Such acute angle impactions are classified as partially erupted when one of the third molar cusps breached the epithelial attachment of the distal aspect of the second molar, thus prevents the formation of a gingival seal. At its earliest stage the wisdom tooth appears clinically absent or unerupted, yet histologically the architecture of the gingival epithelium has been disrupted allowing ingress of microbes, demineralisation and succeeding cavitation to take place on the distal aspect of the second molar. We hope to highlight the difficulties faced in addressing this growing clinical problem and encourage clinicians to re-evaluate their own caries risk assessment and caries prevention strategy in relation to mesial and horizontal third molar extractions.

  14. Link Influence Entropy

    NASA Astrophysics Data System (ADS)

    Singh, Priti; Chakraborty, Abhishek; Manoj, B. S.

    2017-01-01

    In this paper we propose a new metric, Link Influence Entropy (LInE), which describes importance of each node based on the influence of each link present in a network. Influence of a link can neither be effectively estimated using betweenness centrality nor using degree based probability measures. The proposed LInE metric which provides an effective way to estimate the influence of a link in the network and incorporates this influence to identify nodal characteristics, performs better compared to degree based entropy. We found that LInE can differentiate various network types which degree-based or betweenness centrality based node influence metrics cannot. Our findings show that spatial wireless networks and regular grid networks, respectively, have lowest and highest LInE values. Finally, performance analysis of LInE is carried out on a real-world network as well as on a wireless mesh network testbed to study the influence of our metric as well as influence stability of nodes in dynamic networks.

  15. Possible extended forms of thermodynamic entropy

    NASA Astrophysics Data System (ADS)

    Sasa, Shin-ichi

    2014-01-01

    Thermodynamic entropy is determined by a heat measurement through the Clausius equality. The entropy then formalizes a fundamental limitation of operations by the second law of thermodynamics. The entropy is also expressed as the Shannon entropy of the microscopic degrees of freedom. Whenever an extension of thermodynamic entropy is attempted, we must pay special attention to how its three different aspects just mentioned are altered. In this paper, we discuss possible extensions of the thermodynamic entropy.

  16. Configurational entropy of glueball states

    NASA Astrophysics Data System (ADS)

    Bernardini, Alex E.; Braga, Nelson R. F.; da Rocha, Roldão

    2017-02-01

    The configurational entropy of glueball states is calculated using a holographic description. Glueball states are represented by a supergravity dual picture, consisting of a 5-dimensional graviton-dilaton action of a dynamical holographic AdS/QCD model. The configurational entropy is studied as a function of the glueball spin and of the mass, providing information about the stability of the glueball states.

  17. Trajectory versus probability density entropy.

    PubMed

    Bologna, M; Grigolini, P; Karagiorgis, M; Rosa, A

    2001-07-01

    We show that the widely accepted conviction that a connection can be established between the probability density entropy and the Kolmogorov-Sinai (KS) entropy is questionable. We adopt the definition of density entropy as a functional of a distribution density whose time evolution is determined by a transport equation, conceived as the only prescription to use for the calculation. Although the transport equation is built up for the purpose of affording a picture equivalent to that stemming from trajectory dynamics, no direct use of trajectory time evolution is allowed, once the transport equation is defined. With this definition in mind we prove that the detection of a time regime of increase of the density entropy with a rate identical to the KS entropy is possible only in a limited number of cases. The proposals made by some authors to establish a connection between the two entropies in general, violate our definition of density entropy and imply the concept of trajectory, which is foreign to that of density entropy.

  18. Osteomyelitis of the mandible secondary to pericoronitis of an impacted third molar.

    PubMed

    Mohammed-Ali, Ricardo I; Collyer, Jeremy; Garg, Montey

    2010-03-01

    Impacted third molars are a common reason for referral to the hospital dental service. Third molar impaction can be complicated by infection. We present two cases of osteomyelitis of the mandible developing secondary to pericoronitis of partially erupted lower third molars. One of the cases reported was recently diagnosed and treated while the other was diagnosed and treated 20 years ago. The most commonly reported pathology associated with impacted lower third molars is pericoronitis. Osteomyelitis of the mandible secondary to pericoronitis is rare. It is helpful if dental practitioners are able to distinguish between the cases of pericoronitis that need emergency referral to hospital and the cases that can be managed in practice and referred to an outpatient clinic.

  19. Entropy Budget for Hawking Evaporation

    NASA Astrophysics Data System (ADS)

    Alonso-Serrano, Ana; Visser, Matt

    2017-07-01

    Blackbody radiation, emitted from a furnace and described by a Planck spectrum, contains (on average) an entropy of $3.9\\pm 2.5$ bits per photon. Since normal physical burning is a unitary process, this amount of entropy is compensated by the same amount of "hidden information" in correlations between the photons. The importance of this result lies in the posterior extension of this argument to the Hawking radiation from black holes, demonstrating that the assumption of unitarity leads to a perfectly reasonable entropy/information budget for the evaporation process. In order to carry out this calculation we adopt a variant of the "average subsystem" approach, but consider a tripartite pure system that includes the influence of the rest of the universe, and which allows "young" black holes to still have a non-zero entropy; which we identify with the standard Bekenstein entropy.

  20. Histological evaluation of mandibular third molar roots retrieved after coronectomy.

    PubMed

    Patel, Vinod; Sproat, Chris; Kwok, Jerry; Beneng, Kiran; Thavaraj, Selvam; McGurk, Mark

    2014-05-01

    There is a resurgence of interest in coronectomy for the management of mandibular third molars because it has a low risk of injury to the inferior dental nerve. However, there is concern that the root that is left in place will eventually become a source of infection. We describe the histological evaluation of 26 consecutive symptomatic coronectomy roots in 21 patients. All roots had vital tissue in the pulp chamber and there was no evidence of periradicular inflammation. Persistent postoperative symptoms related predominantly to inflammation of the soft tissue, which was caused by partially erupted roots or failure of the socket to heal.

  1. Dentinal innervation of impacted human third molars.

    PubMed

    Lilja, J; Fagerberg-Mohlin, B

    1984-12-01

    Five totally impacted third molars were studied in the transmission electron microscope for the presence of nervous structures in the dentin before eruption. In contradiction to earlier studies available, nervous structures were found in the predentin and the dentin of the impacted third molars in different parts of the crown and also in the predentin of the root.

  2. Analysis of trajectory entropy for continuous stochastic processes at equilibrium.

    PubMed

    Haas, Kevin R; Yang, Haw; Chu, Jhih-Wei

    2014-07-17

    The analytical expression for the trajectory entropy of the overdamped Langevin equation is derived via two approaches. The first route goes through the Fokker-Planck equation that governs the propagation of the conditional probability density, while the second method goes through the path integral of the Onsager-Machlup action. The agreement of these two approaches in the continuum limit underscores the equivalence between the partial differential equation and the path integral formulations for stochastic processes in the context of trajectory entropy. The values obtained using the analytical expression are also compared with those calculated with numerical solutions for arbitrary time resolutions of the trajectory. Quantitative agreement is clearly observed consistently across different models as the time interval between snapshots in the trajectories decreases. Furthermore, analysis of different scenarios illustrates how the deterministic and stochastic forces in the Langevin equation contribute to the variation in dynamics measured by the trajectory entropy.

  3. Tight Uniform Continuity Bounds for Quantum Entropies: Conditional Entropy, Relative Entropy Distance and Energy Constraints

    NASA Astrophysics Data System (ADS)

    Winter, Andreas

    2016-10-01

    We present a bouquet of continuity bounds for quantum entropies, falling broadly into two classes: first, a tight analysis of the Alicki-Fannes continuity bounds for the conditional von Neumann entropy, reaching almost the best possible form that depends only on the system dimension and the trace distance of the states. Almost the same proof can be used to derive similar continuity bounds for the relative entropy distance from a convex set of states or positive operators. As applications, we give new proofs, with tighter bounds, of the asymptotic continuity of the relative entropy of entanglement, E R , and its regularization {E_R^{∞}}, as well as of the entanglement of formation, E F . Using a novel "quantum coupling" of density operators, which may be of independent interest, we extend the latter to an asymptotic continuity bound for the regularized entanglement of formation, aka entanglement cost, {E_C=E_F^{∞}}. Second, we derive analogous continuity bounds for the von Neumann entropy and conditional entropy in infinite dimensional systems under an energy constraint, most importantly systems of multiple quantum harmonic oscillators. While without an energy bound the entropy is discontinuous, it is well-known to be continuous on states of bounded energy. However, a quantitative statement to that effect seems not to have been known. Here, under some regularity assumptions on the Hamiltonian, we find that, quite intuitively, the Gibbs entropy at the given energy roughly takes the role of the Hilbert space dimension in the finite-dimensional Fannes inequality.

  4. General technique of third molar removal.

    PubMed

    Farish, Sam E; Bouloux, Gary F

    2007-02-01

    The most commonly performed surgical procedure in most oral and maxillofacial surgery practices is the removal of impacted third molars. Extensive training, skill, and experience allow this procedure to be performed in an atraumatic fashion with local anesthesia, sedation, or general anesthesia. The decision to remove symptomatic third molars is not usually difficult, but the decision to remove asymptomatic third molars is sometimes less clear and requires clinical experience. A wide body of literature (discussed elsewhere in this issue) attempts to establish clinical practice guidelines for dealing with impacted teeth. Data is beginning to accumulate from third molar studies, which hopefully will provide surgeons and their patients with evidence-based guidelines regarding elective third molar surgery.

  5. The wisdom behind third molar extractions.

    PubMed

    Kandasamy, S; Rinchuse, D J; Rinchuse, D J

    2009-12-01

    The literature pertaining to the extraction of third molars is extensive. There is a large individual variation and a multitude of practitioners' beliefs and biases relating to the extraction of especially asymptomatic and pathology free third molars. With the current emphasis in dentistry being placed on clinicians to make evidence-based decisions, the routine removal of third molars has been re-assessed and questioned. The purpose of this paper was to evaluate past and present knowledge of third molar extractions and relate it to logical considerations relevant to science and the evidence-based decision-making process. This paper endeavours to encourage and stimulate clinicians to re-evaluate their views on third molar extractions based on suggested guidelines and current evidence.

  6. Measurement of granular entropy.

    PubMed

    McNamara, Sean; Richard, Patrick; de Richter, Sébastien Kiesgen; Le Caër, Gérard; Delannay, Renaud

    2009-09-01

    Recently, Dean and Lefèvre [Phys. Rev. Lett. 90, 198301 (2003)] developed a method for testing the statistical mechanical theory of granular packings proposed by Edwards and co-workers [Physica A 157, 1080 (1989); Phys. Rev. E 58, 4758 (1998)]. The method relies on the prediction that the ratio of two overlapping volume histograms should be exponential in volume. We extend the method by showing that one can also calculate the entropy of the packing and also that the method can yield false positive results when the histograms are Gaussians with nearly identical variances. We then apply the method to simulations and experiments of granular compaction. The distribution of global volumes (the volume of the entire packing) is nearly Gaussian and it is difficult to conclude if the theory is valid. On the other hand, the distribution of Voronoï volumes clearly obeys the theoretical prediction.

  7. Revisiting sample entropy analysis

    NASA Astrophysics Data System (ADS)

    Govindan, R. B.; Wilson, J. D.; Eswaran, H.; Lowery, C. L.; Preißl, H.

    2007-03-01

    We modify the definition of sample entropy (SaEn) by incorporating a time delay between the components of the block (from which the densities are estimated) and show that the modified method characterizes the complexity of the system better than the original version. We apply the modified SaEn to the standard deterministic systems and stochastic processes (uncorrelated and long range correlated (LRC) processes) and show that the underlying complexity of the system is better quantified by the modified method. We extend this analysis to the RR intervals of the normal and congestive heart failure (CHF) subjects (available via www.physionet.org) and show that there is a good degree of separation between the two groups.

  8. The evolution of anthropoid molar proportions.

    PubMed

    Carter, Katherine E; Worthington, Steven

    2016-05-20

    Developmental processes that underpin morphological variation have become a focus of interest when attempting to interpret macroevolutionary patterns. Recently, the Dental Inhibitory Cascade (DIC) model has been suggested to explain much of the variation in mammalian molar size proportions. We tested the macroevolutionary implications of this model using anthropoid primate species (n=100), focusing on overall morphological patterns, as well as predictions made about molar size variability, direct developmental control, and diet. Of the species sampled, 56 % had centroids that fell within regions of molar proportion morphospace consistent with the DIC model. We also found that the third molar had greater variation in size than either the first or second molars, as expected by the model. Some DIC model predictions were not supported, however, such as the expected proportion of M 2/M 1 when the third molar is absent. Furthermore, we found that some variability in third molar size could not be explained by the influence of the inhibitory cascade. Overall, we found considerable clade-specific differences in relative molar sizes among anthropoid primates, with hominoids and cercopithecins strongly divergent from DIC model predictions, and platyrrhines, colobines, and papionins more consistent with the inhibitory cascade. Finally, we investigated reasons why some clades deviated from DIC model expectations. Adaptations for frugivory (e.g., bunodont cusp relief) appeared to be one driver of relatively larger second molars and have evolved independently in multiple lineages of anthropoids. The DIC model explains some of the variation in anthropoid primate molar proportions. However, there are interesting deviations away from this broad mammalian pattern, particularly in hominoids and cercopithecins, which suggest the model is only one of multiple mechanisms determining morphological variability in mammalian teeth.

  9. Bayes' estimators of generalized entropies

    NASA Astrophysics Data System (ADS)

    Holste, D.; Große, I.; Herzel, H.

    1998-03-01

    The order-q Tsallis 0305-4470/31/11/007/img5 and Rényi entropy 0305-4470/31/11/007/img6 receive broad applications in the statistical analysis of complex phenomena. A generic problem arises, however, when these entropies need to be estimated from observed data. The finite size of data sets can lead to serious systematic and statistical errors in numerical estimates. In this paper, we focus upon the problem of estimating generalized entropies from finite samples and derive the Bayes estimator of the order-q Tsallis entropy, including the order-1 (i.e. the Shannon) entropy, under the assumption of a uniform prior probability density. The Bayes estimator yields, in general, the smallest mean-quadratic deviation from the true parameter as compared with any other estimator. Exploiting the functional relationship between 0305-4470/31/11/007/img7 and 0305-4470/31/11/007/img8, we use the Bayes estimator of 0305-4470/31/11/007/img7 to estimate the Rényi entropy 0305-4470/31/11/007/img8. We compare these novel estimators with the frequency-count estimators for 0305-4470/31/11/007/img7 and 0305-4470/31/11/007/img8. We find by numerical simulations that the Bayes estimator reduces statistical errors of order-q entropy estimates for Bernoulli as well as for higher-order Markov processes derived from the complete genome of the prokaryote Haemophilus influenzae.

  10. Population entropies estimates of proteins

    NASA Astrophysics Data System (ADS)

    Low, Wai Yee

    2017-05-01

    The Shannon entropy equation provides a way to estimate variability of amino acids sequences in a multiple sequence alignment of proteins. Knowledge of protein variability is useful in many areas such as vaccine design, identification of antibody binding sites, and exploration of protein 3D structural properties. In cases where the population entropies of a protein are of interest but only a small sample size can be obtained, a method based on linear regression and random subsampling can be used to estimate the population entropy. This method is useful for comparisons of entropies where the actual sequence counts differ and thus, correction for alignment size bias is needed. In the current work, an R based package named EntropyCorrect that enables estimation of population entropy is presented and an empirical study on how well this new algorithm performs on simulated dataset of various combinations of population and sample sizes is discussed. The package is available at https://github.com/lloydlow/EntropyCorrect. This article, which was originally published online on 12 May 2017, contained an error in Eq. (1), where the summation sign was missing. The corrected equation appears in the Corrigendum attached to the pdf.

  11. Maxillary second molar impaction in the adjacent ectopic third molar: Report of five rare cases

    PubMed Central

    Souki, Bernardo Q.; Cheib, Paula L.; de Brito, Gabriela M.; Pinto, Larissa S. M. C.

    2015-01-01

    Maxillary second molar impaction in the adjacent ectopic third molar is a rare condition that practitioners might face in the field of pediatric dentistry and orthodontics. The early diagnosis and extraction of the adjacent ectopic third molar have been advocated, and prior research has reported a high rate of spontaneous eruption following third molar removal. However, some challenges in the daily practice are that the early diagnosis of this type of tooth impaction is difficult with conventional radiographic examination, and sometimes the early surgical removal of the maxillary third molar must be postponed because of the risks of damaging the second molar. The objective of this study is to report a case series of five young patients with maxillary second molar impaction and to discuss the difficulty of early diagnosis with the conventional radiographic examination, and unpredictability of self-correction. PMID:26321848

  12. Maxillary second molar impaction in the adjacent ectopic third molar: Report of five rare cases.

    PubMed

    Souki, Bernardo Q; Cheib, Paula L; de Brito, Gabriela M; Pinto, Larissa S M C

    2015-01-01

    Maxillary second molar impaction in the adjacent ectopic third molar is a rare condition that practitioners might face in the field of pediatric dentistry and orthodontics. The early diagnosis and extraction of the adjacent ectopic third molar have been advocated, and prior research has reported a high rate of spontaneous eruption following third molar removal. However, some challenges in the daily practice are that the early diagnosis of this type of tooth impaction is difficult with conventional radiographic examination, and sometimes the early surgical removal of the maxillary third molar must be postponed because of the risks of damaging the second molar. The objective of this study is to report a case series of five young patients with maxillary second molar impaction and to discuss the difficulty of early diagnosis with the conventional radiographic examination, and unpredictability of self-correction.

  13. Intracoronal radiolucency in an incompletely erupted permanent molar with a diagnosis of pericoronitis: importance of radiographic examination.

    PubMed

    Segura, J J; Jiménez-Rubio, A; Cabrera, R

    1998-04-01

    Because of clinical signs and symptoms, a diagnosis of pericoronitis in a partially erupted, partially impacted first molar was made. A more thorough diagnosis was made with the help of a periapical radiograph that showed caries and thus revealed an irreversible pulpitis. Appropriate treatment was the result.

  14. Influence of Pareto optimality on the maximum entropy methods

    NASA Astrophysics Data System (ADS)

    Peddavarapu, Sreehari; Sunil, Gujjalapudi Venkata Sai; Raghuraman, S.

    2017-07-01

    Galerkin meshfree schemes are emerging as a viable substitute to finite element method to solve partial differential equations for the large deformations as well as crack propagation problems. However, the introduction of Shanon-Jayne's entropy principle in to the scattered data approximation has deviated from the trend of defining the approximation functions, resulting in maximum entropy approximants. Further in addition to this, an objective functional which controls the degree of locality resulted in Local maximum entropy approximants. These are based on information-theoretical Pareto optimality between entropy and degree of locality that are defining the basis functions to the scattered nodes. The degree of locality in turn relies on the choice of locality parameter and prior (weight) function. The proper choices of both plays vital role in attain the desired accuracy. Present work is focused on the choice of locality parameter which defines the degree of locality and priors: Gaussian, Cubic spline and quartic spline functions on the behavior of local maximum entropy approximants.

  15. Entanglement entropy converges to classical entropy around periodic orbits

    SciTech Connect

    Asplund, Curtis T.; Berenstein, David

    2016-03-15

    We consider oscillators evolving subject to a periodic driving force that dynamically entangles them, and argue that this gives the linearized evolution around periodic orbits in a general chaotic Hamiltonian dynamical system. We show that the entanglement entropy, after tracing over half of the oscillators, generically asymptotes to linear growth at a rate given by the sum of the positive Lyapunov exponents of the system. These exponents give a classical entropy growth rate, in the sense of Kolmogorov, Sinai and Pesin. We also calculate the dependence of this entropy on linear mixtures of the oscillator Hilbert-space factors, to investigate the dependence of the entanglement entropy on the choice of coarse graining. We find that for almost all choices the asymptotic growth rate is the same.

  16. How will mandibular third molar surgery affect mandibular second molar periodontal parameters?

    PubMed

    Tabrizi, Reza; Arabion, Hamidreza; Gholami, Mehdi

    2013-07-01

    Several conflicting findings have been published in the previous literature regarding the effects of impacted third molar surgery on the periodontal parameters of the adjacent second molar; some authors have shown improvement of periodontal health distal to the adjacent second molar, whilst others have demonstrated loss of attachment level (AL) and reduction of alveolar bone height. The purpose of this study was to evaluate the changes in periodontal health parameters distal to the adjacent second molar following extraction of an impacted third molar. Out of 50 patients participated in the study, 42 patients completed the study. The mean age of the sample was 20.9 (range, 18-25) years. All teeth were mesioangular impacted mandibular third molars categorized at C1 class based on the Pell and Gregory classification. All surgeries were performed by one surgeon and the same surgeon recorded the pre-operative and post-operative measurements of probing depth (PD) and AL on the distobuccal aspect of the second molars. Data analysis were carried out with the SPSS software (version 19), using the paired-samples t-test and one sample t-test. Surgical extraction of impacted mandibular third molar resulted in a significant increase of PD on the distobuccal aspect of the second molars, whereas AL was decreased significantly after surgery (P < 0.05). Unlike plenty of researches that have shown improvement of periodontal parameters of the second molar after extraction of impacted third molar, our study showed a significant increase in PD at the distal aspect of the second molar. Further follow-up on clinical and radiological parameters are required for more profound understanding of the long-term effects of third molar extraction on the periodontal parameters of the adjacent second molar.

  17. Zero modes and entanglement entropy

    NASA Astrophysics Data System (ADS)

    Yazdi, Yasaman K.

    2017-04-01

    Ultraviolet divergences are widely discussed in studies of entanglement entropy. Also present, but much less understood, are infrared divergences due to zero modes in the field theory. In this note, we discuss the importance of carefully handling zero modes in entanglement entropy. We give an explicit example for a chain of harmonic oscillators in 1D, where a mass regulator is necessary to avoid an infrared divergence due to a zero mode. We also comment on a surprising contribution of the zero mode to the UV-scaling of the entanglement entropy.

  18. Entropy distance: New quantum phenomena

    SciTech Connect

    Weis, Stephan; Knauf, Andreas

    2012-10-15

    We study a curve of Gibbsian families of complex 3 Multiplication-Sign 3-matrices and point out new features, absent in commutative finite-dimensional algebras: a discontinuous maximum-entropy inference, a discontinuous entropy distance, and non-exposed faces of the mean value set. We analyze these problems from various aspects including convex geometry, topology, and information geometry. This research is motivated by a theory of infomax principles, where we contribute by computing first order optimality conditions of the entropy distance.

  19. Nonequilibrium stationary states and entropy.

    PubMed

    Gallavotti, G; Cohen, E G D

    2004-03-01

    In transformations between nonequilibrium stationary states, entropy might not be a well defined concept. It might be analogous to the "heat content" in transformations in equilibrium which is not well defined either, if they are not isochoric (i.e., do involve mechanical work). Hence we conjecture that in a nonequilibrium stationary state the entropy is just a quantity that can be transferred or created, such as heat in equilibrium, but has no physical meaning as "entropy content" as a property of the system.

  20. Entropy in statistical energy analysis.

    PubMed

    Le Bot, Alain

    2009-03-01

    In this paper, the second principle of thermodynamics is discussed in the framework of statistical energy analysis (SEA). It is shown that the "vibrational entropy" and the "vibrational temperature" of sub-systems only depend on the vibrational energy and the number of resonant modes. A SEA system can be described as a thermodynamic system slightly out of equilibrium. In steady-state condition, the entropy exchanged with exterior by sources and dissipation exactly balances the production of entropy by irreversible processes at interface between SEA sub-systems.

  1. Sextant of Sapphires for Molar Distalization

    PubMed Central

    Palla, Yudistar Venkata; Ganugapanta, Vivek Reddy

    2016-01-01

    Introduction Space analysis quantifies the amount of crowding within the arches estimating the severity of space discrepancy. The space gaining procedures include extraction and non-extraction procedures like expansion, proximal stripping and molar distalization. Aim To identify features seen in molar distalization cases. Materials and Methods The sample size comprised 20 patients in whom molar distalization was decided as the treatment plan. The study models and lateral cephalograms of all the patients were taken. Occlusograms were obtained. Model analysis and cephalometric analysis were performed. Descriptive statistical analysis like mean, standard deviation, standard error and mode were done. Results The parameters in Question gave following results. The Bolton analysis showed anterior mandibular excess with mean value of 1.56mm±1.07. The first order discrepancy between maxillary central and lateral incisors was 5±1.95. The premolar rotation showed mean value of 16.58±5.12. The molar rotation showed the value of 7.66±2.26. The nasolabial angle showed the mean of 101.25±8.7 IMPA of 101.4±5.74. Conclusion The six features studied in molar distalization cases [First order discrepancy between upper central and lateral incisors; Rotation of premolars and molars; Bolton’s discrepancy in anterior dentition; Average to horizontal growth pattern; Proclined lower incisors and Obtuse nasolabial angle] can be taken as patterns seen in molar distalization cases and considered as a valid treatment plan. PMID:27656572

  2. Sextant of Sapphires for Molar Distalization.

    PubMed

    Ponnada, Swaroopa Rani; Palla, Yudistar Venkata; Ganugapanta, Vivek Reddy

    2016-08-01

    Space analysis quantifies the amount of crowding within the arches estimating the severity of space discrepancy. The space gaining procedures include extraction and non-extraction procedures like expansion, proximal stripping and molar distalization. To identify features seen in molar distalization cases. The sample size comprised 20 patients in whom molar distalization was decided as the treatment plan. The study models and lateral cephalograms of all the patients were taken. Occlusograms were obtained. Model analysis and cephalometric analysis were performed. Descriptive statistical analysis like mean, standard deviation, standard error and mode were done. The parameters in Question gave following results. The Bolton analysis showed anterior mandibular excess with mean value of 1.56mm±1.07. The first order discrepancy between maxillary central and lateral incisors was 5±1.95. The premolar rotation showed mean value of 16.58±5.12. The molar rotation showed the value of 7.66±2.26. The nasolabial angle showed the mean of 101.25±8.7 IMPA of 101.4±5.74. The six features studied in molar distalization cases [First order discrepancy between upper central and lateral incisors; Rotation of premolars and molars; Bolton's discrepancy in anterior dentition; Average to horizontal growth pattern; Proclined lower incisors and Obtuse nasolabial angle] can be taken as patterns seen in molar distalization cases and considered as a valid treatment plan.

  3. Maximum entropy spectral analysis for streamflow forecasting

    NASA Astrophysics Data System (ADS)

    Cui, Huijuan; Singh, Vijay P.

    2016-01-01

    Configurational entropy spectral analysis (CESAS) is developed with spectral power as a random variable for streamflow forecasting. It is found that the CESAS derived by maximizing the configurational entropy yields the same solution as by the Burg entropy spectral analysis (BESA). Comparison of forecasted streamflows by CESAS and BESA shows less than 0.001% difference between the two analyses and thus the two entropy spectral analyses are concluded to be identical. Thus, the Burg entropy spectral analysis and two configurational entropy spectral analyses form the maximum entropy spectral analysis.

  4. Entropy exchange for infinite-dimensional systems

    PubMed Central

    Duan, Zhoubo; Hou, Jinchuan

    2017-01-01

    In this paper the entropy exchange for channels and states in infinite-dimensional systems are defined and studied. It is shown that, this entropy exchange depends only on the given channel and the state. An explicit expression of the entropy exchange in terms of the state and the channel is proposed. The generalized Klein’s inequality, the subadditivity and the triangle inequality about the entropy including infinite entropy for the infinite-dimensional systems are established, and then, applied to compare the entropy exchange with the entropy change. PMID:28164995

  5. Unilateral Molar Distalization: A Nonextraction Therapy

    PubMed Central

    Prasad, M. Bhanu; Sreevalli, S.

    2012-01-01

    In the recent years, nonextraction treatment approaches and noncompliance therapies have become more popular in the correction of space discrepancies. One of the conventional approaches for space gaining in the arches without patient compliance is done by using certain extra oral appliances or intraoral appliance. The greatest advantage of certain appliances like fixed functional and molar distalization appliances is that they minimize the dependence on patient cooperation. Molar distalization appliances like pendulum appliance which distalizes the molar rapidly without the need of head gear can be used in patients as a unilateral space gaining procedure due to buccal segment crowding. PMID:23320203

  6. Role of third molars in orthodontics

    PubMed Central

    Almpani, Konstantinia; Kolokitha, Olga-Elpis

    2015-01-01

    The role of third molars in the oral cavity has been extensively studied over the years. Literature includes numerous diagnostic and treatment alternatives regarding the third molars. However, an issue that has not been discussed at the same level is their involvement in orthodontic therapy. The aim of this study is to present a review of the contemporary literature regarding the most broadly discussed aspects of the multifactorial role of third molars in orthodontics and which are of general dental interest too. PMID:25685759

  7. Entropy of Open Lattice Systems

    NASA Astrophysics Data System (ADS)

    Derrida, B.; Lebowitz, J. L.; Speer, E. R.

    2007-03-01

    We investigate the behavior of the Gibbs-Shannon entropy of the stationary nonequilibrium measure describing a one-dimensional lattice gas, of L sites, with symmetric exclusion dynamics and in contact with particle reservoirs at different densities. In the hydrodynamic scaling limit, L → ∞, the leading order ( O( L)) behavior of this entropy has been shown by Bahadoran to be that of a product measure corresponding to strict local equilibrium; we compute the first correction, which is O(1). The computation uses a formal expansion of the entropy in terms of truncated correlation functions; for this system the k th such correlation is shown to be O( L - k+1). This entropy correction depends only on the scaled truncated pair correlation, which describes the covariance of the density field. It coincides, in the large L limit, with the corresponding correction obtained from a Gaussian measure with the same covariance.

  8. Entropy balance in holographic superconductors

    NASA Astrophysics Data System (ADS)

    Hartnoll, Sean A.; Pourhasan, Razieh

    2012-07-01

    In systems undergoing second order phase transitions, the temperature integral of the specific heat over temperature from zero to the critical temperature is the same in both the normal and ordered phases. This entropy balance relates the critical temperature to the distribution of degrees of freedom in the normal and ordered states. Quantum criticality and fractionalization can imply an increased number of low energy degrees of freedom in both the normal and ordered states. We explore the rôle of entropy balance in holographic models of superconductivity, focussing on the interplay between quantum criticality and superconductivity. We consider models with and without a ground state entropy density in the normal phase; the latter models are a new class of holographic superconductors. We explain how a normal phase entropy density manifests itself in the stable superconducting phase.

  9. Entanglement entropy in flat holography

    NASA Astrophysics Data System (ADS)

    Jiang, Hongliang; Song, Wei; Wen, Qiang

    2017-07-01

    BMS symmetry, which is the asymptotic symmetry at null infinity of flat spacetime, is an important input for flat holography. In this paper, we give a holographic calculation of entanglement entropy and Rényi entropy in three dimensional Einstein gravity and Topologically Massive Gravity. The geometric picture for the entanglement entropy is the length of a spacelike geodesic which is connected to the interval at null infinity by two null geodesics. The spacelike geodesic is the fixed points of replica symmetry, and the null geodesics are along the modular flow. Our strategy is to first reformulate the Rindler method for calculating entanglement entropy in a general setup, and apply it for BMS invariant field theories, and finally extend the calculation to the bulk.

  10. An adaptable binary entropy coder

    NASA Technical Reports Server (NTRS)

    Kiely, A.; Klimesh, M.

    2001-01-01

    We present a novel entropy coding technique which is based on recursive interleaving of variable-to-variable length binary source codes. We discuss code design and performance estimation methods, as well as practical encoding and decoding algorithms.

  11. Orientational high-entropy alloys

    NASA Astrophysics Data System (ADS)

    Kumar, Nitesh; Subramaniam, Anandh

    2014-12-01

    In high-entropy alloys (HEA), the configurational entropy arising from the presence of multiple elements, stabilizes a disordered solid solution in preference to the possible formation of compounds. In the current work, we identify cluster compounds (of the type AM4X8) as orientational analogues of HEA (as a first report on orientational high-entropy systems). In cluster compounds, orientational disorder increases the entropy and plays a role analogous to positional disorder in HEA. In the GaMo4S8 compound, at temperatures greater than 50 K, the entropic benefit more than makes up for the strain energy cost and stabilizes the disordered phase in preference to an orientationally ordered compound.

  12. Quantum entropy and special relativity.

    PubMed

    Peres, Asher; Scudo, Petra F; Terno, Daniel R

    2002-06-10

    We consider a single free spin- 1 / 2 particle. The reduced density matrix for its spin is not covariant under Lorentz transformations. The spin entropy is not a relativistic scalar and has no invariant meaning.

  13. High-Entropy Metallic Glasses

    NASA Astrophysics Data System (ADS)

    Wang, W. H.

    2014-10-01

    The high-entropy alloys are defined as solid-solution alloys containing five or more than five principal elements in equal or near-equal atomic percent. The concept of high mixing entropy introduces a new way for developing advanced metallic materials with unique physical and mechanical properties that cannot be achieved by the conventional microalloying approach based on only a single base element. The metallic glass (MG) is the metallic alloy rapidly quenched from the liquid state, and at room temperature it still shows an amorphous liquid-like structure. Bulk MGs represent a particular class of amorphous alloys usually with three or more than three components but based on a single principal element such as Zr, Cu, Ce, and Fe. These materials are very attractive for applications because of their excellent mechanical properties such as ultrahigh (near theoretical) strength, wear resistance, and hardness, and physical properties such as soft magnetic properties. In this article, we review the formation and properties of a series of high-mixing-entropy bulk MGs based on multiple major elements. It is found that the strategy and route for development of the high-entropy alloys can be applied to the development of the MGs with excellent glass-forming ability. The high-mixing-entropy bulk MGs are then loosely defined as metallic glassy alloys containing five or more than five elements in equal or near-equal atomic percent, which have relatively high mixing entropy compared with the conventional MGs based on a single principal element. The formation mechanism, especially the role of the mixing entropy in the formation of the high-entropy MGs, is discussed. The unique physical, mechanical, chemical, and biomedical properties of the high-entropy MGs in comparison with the conventional metallic alloys are introduced. We show that the high-mixing-entropy MGs, along the formation idea and strategy of the high-entropy alloys and based on multiple major elements, might provide

  14. Prevalence of Distal Caries in Mandibular Second Molar Due to Impacted Third Molar

    PubMed Central

    Alshahrani, Fatima Saeed; Alabsi, Wejdan Saad; Alqahtani, Zainab Ali; Hameed, Mohammad Shahul; Mustafa, Abdel Bagi; Alam, Tanveer

    2017-01-01

    Introduction A tooth is said to be impacted if it does not reach the occlusal plane even after two-thirds root formation. The aetiology of impacted teeth is varied and multi-factorial. Significant problems associated with impacted teeth include trismus, infection, cervical caries of second molars. Aim This study was aimed to assess the prevalence of distal caries in second molar teeth due to impacted third molars and to compare with similar studies conducted elsewhere. Materials and Methods Study included assessment of patients reporting between 2009 to 2014 for dental care at College of Dentistry, King Khalid University, Abha, Kingdom of Saudi Arabia. This is a retrospective cross-sectional study which included a total of 6000 Orthopantomograms (OPGs). The data collected was decoded and entered into excel spread sheet. Descriptive analysis of the data was done and results were displayed as frequency table and graphs. Results A total of 979 patients had impacted third molars (16.31%). A total of 39% patient’s with impacted third molars had distal cervical caries in second molar. Mesioangular impaction was the most prominent type. This was closely followed by horizontal impaction causing distal caries in second molars. Age group between 21-28 years and male gender had the higher prevalence of distal caries in second molar teeth due to impacted third molars. Conclusion A total of 39% of the patients with impacted mandibular third molars had distal cervical caries in second molars. Mesioangular type, male gender, age group 21-28 years were the prominent factors associated with distal caries in second molar teeth due to impacted third molars. PMID:28511504

  15. Extremal surfaces and entanglement entropy

    NASA Astrophysics Data System (ADS)

    Pal, Shesansu Sekhar

    2014-05-01

    We have obtained the equation of the extremal hypersurface by considering the Jacobson-Myers functional and computed the entanglement entropy. In this context, we show that the higher derivative corrected extremal surfaces cannot penetrate the horizon. Also, we have studied the entanglement temperature and entanglement entropy for low excited states for such higher derivative theories when the entangling region is of the strip type.

  16. Steganography Detection Using Entropy Measures

    DTIC Science & Technology

    2012-08-19

    REPORT Steganography Detection Using Entropy Measures 14. ABSTRACT 16. SECURITY CLASSIFICATION OF: There are two problems in steganalysis: (1) detecting...the existence of a hidden message and (2) decoding the message. As terrorist groups have been known to use steganography in planning their attacks...298 (Rev 8/98) Prescribed by ANSI Std. Z39.18 - Steganography Detection Using Entropy Measures Report Title ABSTRACT There are two problems in

  17. Boundary effects in entanglement entropy

    NASA Astrophysics Data System (ADS)

    Berthiere, Clément; Solodukhin, Sergey N.

    2016-09-01

    We present a number of explicit calculations of Renyi and entanglement entropies in situations where the entangling surface intersects the boundary of d-dimensional Minkowski spacetime. When the boundary is a single plane we compute the contribution to the entropy due to this intersection, first in the case of the Neumann and Dirichlet boundary conditions, and then in the case of a generic Robin type boundary condition. The flow in the boundary coupling between the Neumann and Dirichlet phases is analyzed in arbitrary dimension d and is shown to be monotonic, the peculiarity of d = 3 case is noted. We argue that the translational symmetry along the entangling surface is broken due the presence of the boundary which reveals that the entanglement is not homogeneous. In order to characterize this quantitatively, we introduce a density of entanglement entropy and compute it explicitly. This quantity clearly indicates that the entanglement is maximal near the boundary. We then consider the situation where the boundary is composed of two parallel planes at a finite separation and compute the entanglement entropy as well as its density in this case. The complete contribution to entanglement entropy due to the boundaries is shown not to depend on the distance between the planes and is simply twice the entropy in the case of single plane boundary. Additionally, we find how the area law, the part in the entropy proportional to the area of entire entangling surface, depends on the size of the separation between the two boundaries. The latter is shown to appear in the UV finite part of the entropy.

  18. Holographic avatars of entanglement entropy

    NASA Astrophysics Data System (ADS)

    Barbón, J. L. F.

    2009-07-01

    This is a rendering of the blackboard lectures at the 2008 Cargese summer school, discussing some elementary facts regarding the application of AdS/CFT techniques to the computation of entanglement entropy in strongly coupled systems. We emphasize the situations where extensivity of the entanglement entropy can be used as a crucial criterion to characterize either nontrivial dynamical phenomena at large length scales, or nonlocality in the short-distance realm.

  19. Incidence of deep fascial space infection after surgical removal of the mandibular third molars.

    PubMed

    Yoshii, T; Hamamoto, Y; Muraoka, S; Kohjitani, A; Teranobu, O; Furudoi, S; Komori, T

    2001-03-01

    Nine hundred and ninety-three patients who underwent surgical removal of the mandibular third molars with oral antibiotic prophylaxis were examined to determine the incidence of postoperative deep fascial space infection and its background factors. Postoperative deep fascial space infection was observed in 8 of the patients (0.8%; 4 males and 4 females), and submandibular spaces were involved in all infected patients. Only 1 of these 8 patients was an immune compromised host. Patients aged 30 years or more had a significantly higher incidence of deep fascial space infection than those aged under 30. Five patients had partial bony impactions and 3 had complete bony impactions. However, the incidence of infection according to the molar positions was not significantly different between partial bony impaction and complete bony impaction. The 8 patients had not had pericoronitis preoperatively. The clinical courses of all were favorable after antibiotics were administered intravenously. In conclusion, the incidence of deep fascial space infection after removal of the mandibular third molars was low, at 0.8%. However, it may be desirable to remove the molars, if applicable, at a younger age because of the higher incidence of infection in patients aged over 30. The results of this study also offer information that will be useful as a basis for obtaining informed consent from patients whose mandibular third molars are to be removed.

  20. Entropy Production in Chemical Reactors

    NASA Astrophysics Data System (ADS)

    Kingston, Diego; Razzitte, Adrián C.

    2017-06-01

    We have analyzed entropy production in chemically reacting systems and extended previous results to the two limiting cases of ideal reactors, namely continuous stirred tank reactor (CSTR) and plug flow reactor (PFR). We have found upper and lower bounds for the entropy production in isothermal systems and given expressions for non-isothermal operation and analyzed the influence of pressure and temperature in entropy generation minimization in reactors with a fixed volume and production. We also give a graphical picture of entropy production in chemical reactions subject to constant volume, which allows us to easily assess different options. We show that by dividing a reactor into two smaller ones, operating at different temperatures, the entropy production is lowered, going as near as 48 % less in the case of a CSTR and PFR in series, and reaching 58 % with two CSTR. Finally, we study the optimal pressure and temperature for a single isothermal PFR, taking into account the irreversibility introduced by a compressor and a heat exchanger, decreasing the entropy generation by as much as 30 %.

  1. Generalized Maximum Entropy

    NASA Technical Reports Server (NTRS)

    Cheeseman, Peter; Stutz, John

    2005-01-01

    A long standing mystery in using Maximum Entropy (MaxEnt) is how to deal with constraints whose values are uncertain. This situation arises when constraint values are estimated from data, because of finite sample sizes. One approach to this problem, advocated by E.T. Jaynes [1], is to ignore this uncertainty, and treat the empirically observed values as exact. We refer to this as the classic MaxEnt approach. Classic MaxEnt gives point probabilities (subject to the given constraints), rather than probability densities. We develop an alternative approach that assumes that the uncertain constraint values are represented by a probability density {e.g: a Gaussian), and this uncertainty yields a MaxEnt posterior probability density. That is, the classic MaxEnt point probabilities are regarded as a multidimensional function of the given constraint values, and uncertainty on these values is transmitted through the MaxEnt function to give uncertainty over the MaXEnt probabilities. We illustrate this approach by explicitly calculating the generalized MaxEnt density for a simple but common case, then show how this can be extended numerically to the general case. This paper expands the generalized MaxEnt concept introduced in a previous paper [3].

  2. Acute inflammation at a mandibular solitary horizontal incompletely impacted molar

    PubMed Central

    Yamaoka, Minoru; Ono, Yusuke; Ishizuka, Masahide; Hasumi-Nakayama, Yoko; Doto, Ryosuke; Yasuda, Kouichi; Uematsu, Takashi; Furusawa, Kiyofumi

    2009-01-01

    Acute inflammation is frequently seen in the elderly around incompletely impacted molars located apart from molars or premolars. To identify the factors causing acute inflammation in the solitary molars without second molars or without second and first molars, ages of patients and rates of acute inflammation in 75 horizontal incompletely impacted mandibular molars in contact or not in contact with molars in subjects 41 years old or older were studied using orthopantomographs. Acute inflammation was seen in nine third molars out of 48 third molars in contact with second molars (18.8%), whereas acute inflammation was seen in 11 molars out of 19 solitary molars without second molars or without first and second molars (57.9%) (p < 0.01). The mean age of 48 subjects with third molars in contact with the second molar was 50.42 ± 7.62 years, and the mean age of 19 subjects with isolated molars was 65.16 ± 10.41 years (p < 0.0001). These indicate that a solitary horizontal incompletely impacted molar leads more frequently to acute inflammation along with aging due to possible bone resorption resulting from teeth loss. PMID:20360889

  3. Maximum-entropy principle as Galerkin modelling paradigm

    NASA Astrophysics Data System (ADS)

    Noack, Bernd R.; Niven, Robert K.; Rowley, Clarence W.

    2012-11-01

    We show how the empirical Galerkin method, leading e.g. to POD models, can be derived from maximum-entropy principles building on Noack & Niven 2012 JFM. In particular, principles are proposed (1) for the Galerkin expansion, (2) for the Galerkin system identification, and (3) for the probability distribution of the attractor. Examples will illustrate the advantages of the entropic modelling paradigm. Partially supported by the ANR Chair of Excellence TUCOROM and an ADFA/UNSW Visiting Fellowship.

  4. Molars and incisors: show your microarray IDs

    PubMed Central

    2013-01-01

    Background One of the key questions in developmental biology is how, from a relatively small number of conserved signaling pathways, is it possible to generate organs displaying a wide range of shapes, tissue organization, and function. The dentition and its distinct specific tooth types represent a valuable system to address the issues of differential molecular signatures. To identify such signatures, we performed a comparative transcriptomic analysis of developing murine lower incisors, mandibular molars and maxillary molars at the developmental cap stage (E14.5). Results 231 genes were identified as being differentially expressed between mandibular incisors and molars, with a fold change higher than 2 and a false discovery rate lower than 0.1, whereas only 96 genes were discovered as being differentially expressed between mandibular and maxillary molars. Numerous genes belonging to specific signaling pathways (the Hedgehog, Notch, Wnt, FGF, TGFβ/BMP, and retinoic acid pathways), and/or to the homeobox gene superfamily, were also uncovered when a less stringent fold change threshold was used. Differential expressions for 10 out of 12 (mandibular incisors versus molars) and 9 out of 10 selected genes were confirmed by quantitative reverse transcription-PCR (qRT-PCR). A bioinformatics tool (Ingenuity Pathway Analysis) used to analyze biological functions and pathways on the group of incisor versus molar differentially expressed genes revealed that 143 genes belonged to 9 networks with intermolecular connections. Networks with the highest significance scores were centered on the TNF/NFκB complex and the ERK1/2 kinases. Two networks ERK1/2 kinases and tretinoin were involved in differential molar morphogenesis. Conclusion These data allowed us to build several regulatory networks that may distinguish incisor versus molar identity, and may be useful for further investigations of these tooth-specific ontogenetic programs. These programs may be dysregulated in

  5. Clinical management of the mandibular molars.

    PubMed

    Canut, J A

    1975-09-01

    The complex variety of clinical problems posed by the lower molars requires maximum care in diagnosis and in treatment planning. In this article several therapeutic solutions to these problems are presented. The need to treat positional anomalies of the second molars and to control their drifting in cases of bracing and mandibular insertion, may be an effective auxillary means of treatment of those malocclusions in which lengthening of the dental bracing zones is indicated.

  6. Retrospective analysis of the prevalence and incidence of caries in the distal surface of mandibular second molars in British military personnel.

    PubMed

    Pepper, T; Grimshaw, P; Konarzewski, T; Combes, J

    2017-02-01

    Mandibular third molars are commonly removed because of distal caries in the adjacent tooth. To find out the prevalence of distal caries in mandibular second molars we retrospectively studied the primary care dental records of 720 British military personnel (653 men and 67 women) from various centres. These records are standardised and personnel are required to attend for inspection regularly. Those who had been under 20 years of age at enlistment, who had served for at least five years, and had five recorded dental inspections, were included. The median (IQR) period from the first to last inspection was 15 (9.7 - 19.2) years, and inspections were a median (IQR) of 14.1 (12.8 - 15.8) months apart. A total of 59/1414 (4.2%) mandibular second molars developed caries in their distal surfaces. This was 4% higher when they were associated with a partially-erupted mandibular third molar than when associated with one that was fully erupted or absent (29/414 (7%) compared with 30/1000 (3%); p=0.001). Carious lesions developed in the distal aspect of 22/133 mandibular second molars (16.5%) that were adjacent to a mesioangularly impacted third molar. Of these, 19/22 were successfully restored. Four mesioangularly impacted mandibular third molars would have to be extracted to prevent one case of distal caries in a second molar (number needed to treat=3.25). Second molars that are associated with a partially-erupted mesioangular mandibular third molar have a higher risk of caries, and this can be reduced by removal of the third molar. However, distal caries in second molars seems to be a treatable and slowly-developing phenomenon and we recommend that the merits and risks of the prophylactic removal of third molars should be discussed with the patient, who should have long-term clinical and radiographic checks if the tooth is retained.

  7. Molar shape variability in platyrrhine primates.

    PubMed

    Nova Delgado, Mónica; Galbany, Jordi; Pérez-Pérez, Alejandro

    2016-10-01

    Recent phylogenetic analyses suggest that platyrrhines constitute a monophyletic group represented by three families: Cebidae, Atelidae, and Pitheciidae. Morphological variability between and within these three families, however, is widely discussed and debated. The aim of this study was to assess molar shape variability in platyrrhines, to explore patterns of interspecific variation among extant species, and to evaluate how molar shape can be used as a taxonomic indicator. The analyses were conducted using standard multivariate analyses of geometric morphometric data from 802 platyrrhine lower molars. The results indicated that the interspecific variation exhibited a highly homoplastic pattern related to functional adaptation of some taxa. However, phylogeny was also an important factor in shaping molar morphological traits, given that some phenotypic similarities were consistent with current phylogenetic positions. Our results show that the phylogenetic and functional signals of lower molar shape vary depending on the taxa and the tooth considered. Based on molar shape, Aotus showed closer similarities to Callicebus, as well as to some Cebidae and Ateles-Lagothrix, due to convergent evolutionary trends caused by similar dietary habits, or due to fast-evolving branches in the Aotus lineage, somewhat similar to the shape of Callicebus and Cebidae.

  8. Maxillary molar distalization with first class appliance

    PubMed Central

    Ramesh, Namitha; Palukunnu, Biswas; Ravindran, Nidhi; Nair, Preeti P

    2014-01-01

    Non-extraction treatment has gained popularity for corrections of mild-to-moderate class II malocclusion over the past few decades. The distalization of maxillary molars is of significant value for treatment of cases with minimal arch discrepancy and mild class II molar relation associated with a normal mandibular arch and acceptable profile. This paper describes our experience with a 16-year-old female patient who reported with irregularly placed upper front teeth and unpleasant smile. The patient was diagnosed to have angles class II malocclusion with moderate maxillary anterior crowding, deep bite of 4 mm on a skeletal class II base with an orthognathic maxilla and retrognathic mandible and normal growth pattern. She presented an ideal profile and so molar distalization was planned with the first-class appliance. Molars were distalised by 8 mm on the right and left quadrants and class I molar relation achieved within 4 months. The space gained was utilised effectively to align the arch and establish a class I molar and canine relation. PMID:24577171

  9. Incremental lines in mouse molar enamel.

    PubMed

    Sehic, Amer; Nirvani, Minou; Risnes, Steinar

    2013-10-01

    The purpose of the present study was to investigate the occurrence and periodicity of enamel incremental lines in mouse molars in an attempt to draw attention to some key questions about the rhythm in the activity of the secreting ameloblasts during formation of mouse molar enamel. The mouse molars were ground, etched, and studied using scanning electron microscopy. Lines interpreted as incremental lines generally appeared as grooves of variable distinctness, and were only observed cervically, in the region about 50-250μm from the enamel-cementum junction. The lines were most readily observable in the outer enamel and in the superficial prism-free layer, and were difficult to identify in the deeper parts of enamel, i.e. in the inner enamel with prism decussation. However, in areas where the enamel tended to be hypomineralized the incremental lines were observed as clearly continuous from outer into inner enamel. The incremental lines in mouse molar enamel exhibited an average periodicity of about 4μm, and the distance between the lines decreased towards the enamel surface. We conclude that incremental lines are to some extent visible in mouse molar enamel. Together with data from the literature and theoretical considerations, we suggest that they probably represent a daily rhythm in enamel formation. This study witnesses the layered apposition of mouse molar enamel and supports the theory that circadian clock probably regulates enamel development. Copyright © 2013 Elsevier Ltd. All rights reserved.

  10. Maxillary molar distalization with first class appliance.

    PubMed

    Ramesh, Namitha; Palukunnu, Biswas; Ravindran, Nidhi; Nair, Preeti P

    2014-02-27

    Non-extraction treatment has gained popularity for corrections of mild-to-moderate class II malocclusion over the past few decades. The distalization of maxillary molars is of significant value for treatment of cases with minimal arch discrepancy and mild class II molar relation associated with a normal mandibular arch and acceptable profile. This paper describes our experience with a 16-year-old female patient who reported with irregularly placed upper front teeth and unpleasant smile. The patient was diagnosed to have angles class II malocclusion with moderate maxillary anterior crowding, deep bite of 4 mm on a skeletal class II base with an orthognathic maxilla and retrognathic mandible and normal growth pattern. She presented an ideal profile and so molar distalization was planned with the first-class appliance. Molars were distalised by 8 mm on the right and left quadrants and class I molar relation achieved within 4 months. The space gained was utilised effectively to align the arch and establish a class I molar and canine relation.

  11. Prevalence of asymmetric molar and canine relationship.

    PubMed

    Behbehani, Faraj; Roy, Rino; Al-Jame, Badreia

    2012-12-01

    The purpose of this study was to investigate the prevalence and severity of occlusal asymmetries in the molar and canine regions in a large population-based sample of adolescent Kuwaitis. Using a stratified cluster sampling method, 1299 Kuwaiti adolescents (674 boys mean age 13.3 years and 625 girls mean age 13.2 years), representing approximately 6.7 per cent of that age stratum in the population, were examined clinically for sagittal molar and canine relationships, with a view to recording half and full-step asymmetries. In this sample, 1244 subjects were examined clinically, while for the remaining 55, pre-treatment study models were assessed. All subjects were in the early permanent dentition stage. Descriptive statistical analyses were used to determine the proportion of different molar and canine asymmetries. Antero-posterior asymmetries were found to be a distinctive and common feature of the dental arches, with half-step outweighing full-step asymmetries both in the anterior and posterior regions. The total prevalence of an asymmetric molar or canine relationship was 29.7 and 41.4 per cent, respectively, with more than 95 per cent falling in the mild category. Patient gender did not influence the prevalence or magnitude of asymmetry. The results showed a clinically significant prevalence of asymmetric molar and canine relationships, which were mainly in the category of half-step asymmetry. Class II half and full-step asymmetries were more prevalent than Class III asymmetries in the molar and canine regions.

  12. Angulation of mandibular third molars as a predictive factor for pericoronitis.

    PubMed

    Hazza'a, Abdalla M; Bataineh, Anwar Barakat; Odat, Abd-Albaset

    2009-05-01

    The aims of this study were to investigate the association between pericoronitis and the angular position, state of eruption, and the depth of impaction of mandibular third molars as well as to compare these findings with similar studies. A total of 242 patients ranging in age from 18 to 41 years of age suffering from pericoronitis were examined. Subjective and objective observations were recorded on a checklist that included the name, age, gender, type of pericoronitis and state of eruption, position of the affected tooth for each patient as well as any radiographic changes in the mandibular third molars. The peak age for the occurrence of pericoronitis was in the 21-25 year-old age group. The soft tissues adjacent to vertically inclined, partially erupted mandibular third molars at the level of or above the occlusal plane were the most commonly affected. There was a statistically significant association between radiographic changes and the mesioangular position of the tooth (p<0.002) and the age group of the subject (p=0.004), but the association was not statistically significant between the gender of the subject, type of pericoronitis, state of eruption, and depth of impaction. The soft tissues adjacent to vertically inclined, partially erupted mandibular third molars were more frequently affected by pericoronitis than teeth that are soft tissue impacted or erupted. Mesioangular erupted third molars were the teeth most frequently associated with bone loss. The soft tissues at highest risk of developing pericoronitis are those adjacent to mandibular third molars that are partially erupted, in a vertical position, and erupted to the level of or above the occlusal plane.

  13. Entropy-Stabilized Oxides

    DTIC Science & Technology

    2015-09-29

    early 1900s when Goldschmidt reported the ‘the method of chemical substitution’1 that combined a tabulation of cationic and anionic radii with...predictions4. There are, however, limitations to the predictive power, particularly when factors like partial covalency and heterodesmic bonding are...similar. Both observations are only consistent with a random cation distribution. As a corroborating measure of local homogeneity, chemical analysis

  14. Evaluation of postoperative complications according to treatment of third molars in mandibular angle fracture

    PubMed Central

    2017-01-01

    Objectives The aim of this study was to evaluate the implication of third molars in postoperative complications of mandibular angle fracture with open reduction and internal fixation (ORIF). Materials and Methods Data were collected on patients who presented with mandibular angle fracture at our Department of Oral and Maxillofacial Surgery between January 2011 and December 2015. Of the 63 total patients who underwent ORIF and perioperative intermaxillary fixation (IMF) with an arch bar, 49 patients were identified as having third molars in the fracture line and were followed up with until plate removal. The complications of postoperative infection, postoperative nerve injury, bone healing, and changes in occlusion and temporomandibular joint were evaluated and analyzed using statistical methods. Results In total, 49 patients had third molars in the fracture line and underwent ORIF surgery and perioperative IMF with an arch bar. The third molar in the fracture line was retained during ORIF in 39 patients. Several patients complained of nerve injury, temporomandibular disorder (TMD), change of occlusion, and postoperative infection around the retained third molar. The third molars were removed during ORIF surgery in 10 patients. Some of these patients complained of nerve injury, but no other complications, such as TMD, change in occlusion, or postoperative infection, were observed. There was no delayed union or nonunion in either of the groups. No statistically significant difference was found between the non-extraction group and the retained teeth group regarding complications after ORIF. Conclusion If the third molar is partially impacted or completely nonfunctional, likely to be involved in pathologic conditions later in life, or possible to remove with the plate simultaneously, extraction of the third molar in the fracture line should be considered during ORIF surgery of the mandible angle fracture. PMID:28280708

  15. Topological and spatial aspects of the hydration of solutes of extreme solvation entropy

    NASA Astrophysics Data System (ADS)

    Bergman, Dan L.; Lyubartsev, Alexander P.; Laaksonen, Aatto

    1999-10-01

    The hydration of charged Lennard-Jones spheres by simple point charge water is considered. Molecular dynamics and expanded ensemble simulations were used to compare the hydration structures surrounding solutes with extreme solvation entropy. The variations in the solvation entropy were analyzed in terms of changes in the spatial and topological structure of the hydration shells. The solvation entropy was found to be maximal for solutes that can replace water molecules in the hydrogen-bond network. Further, using a Kirkwood-type factorization, the solvation entropy was expanded as a sum over the partial n-body distribution functions. The two-body solute-water contribution to the solvation entropy was found to exceed the full solvation entropy for solutes with low charge, whereas the converse is true for the other solutes. This is consistent with the idea that water-water correlations are enhanced by solvation of, for example, noble gases, whereas they are disrupted by solvation of ions. Further, the orientational and radial parts of the two-body solute-water entropy were calculated as functions of the charge of the solute. The orientational part has a single maximum, whereas the radial part maintains the bimodal form of the full solvation entropy.

  16. Algebraic approach to entanglement and entropy

    NASA Astrophysics Data System (ADS)

    Balachandran, A. P.; Govindarajan, T. R.; de Queiroz, Amilcar R.; Reyes-Lega, A. F.

    2013-08-01

    We present a general approach to quantum entanglement and entropy that is based on algebras of observables and states thereon. In contrast to more standard treatments, Hilbert space is an emergent concept, appearing as a representation space of the observable algebra, once a state is chosen. In this approach, which is based on the Gel'fand-Naimark-Segal construction, the study of subsystems becomes particularly clear. We explicitly show how the problems associated with the partial trace for the study of entanglement of identical particles are readily overcome. In particular, a suitable entanglement measure is proposed that can be applied to systems of particles obeying Fermi, Bose, para-, and even braid-group statistics. The generality of the method is also illustrated by study of the time evolution of subsystems emerging from restriction to subalgebras. Problems related to anomalies and quantum epistemology are also discussed.

  17. Molecular structure, configurational entropy and viscosity of silicate melts: link through the Adam and Gibbs theory of viscous flow

    NASA Astrophysics Data System (ADS)

    Le Losq, Charles; Neuville, Daniel R.

    2016-04-01

    communication, it is shown that such link is possible. By expressing the residual entropy of the glass as the sum of partial molar entropies of tetrahedral SiO2 units, with known quantities from 29Si NMR spectroscopy, and of a semi-ideal mixing of Na and K, it is possible to model the variations of the configurational entropy with chemical composition. The model reproduces the variations of the viscosity of melts with a standard deviation of 0.2 log unit in the K2O-Na2O-SiO2 ternary system, for SiO2 contents between 60 and 100 mol% SiO2. Such model opens new pathways in order to build semi-empirical viscosity models that provide structural, thermodynamic and rheological information about silicate melts.

  18. Diagnosis of molar pregnancy and persistent trophoblastic disease by flow cytometry.

    PubMed Central

    Hemming, J D; Quirke, P; Womack, C; Wells, M; Elston, C W; Bird, C C

    1987-01-01

    Histopathological assessment and flow cytometric analyses were carried out on 32 placentas (representative of each trimester) and 88 molar pregnancies. Three first trimester placentas were triploid, and the remaining 29 placentas were diploid. Of the 88 cases originally diagnosed as molar pregnancies, 26 were triploid (two complete moles, 20 partial moles, and four hydropic abortions); 59 were diploid (46 complete moles, 10 partial moles, three hydropic abortions); one was tetraploid (partial mole); and two were DNA aneuploid (one partial mole, one complete mole). A significantly increased hyperdiploid fraction (a measure of cell proliferation) was detected in diploid complete moles (p less than 0.0001) and cases of persistent trophoblastic disease (p less than 0.001) when compared with diploid placentas and diploid partial moles. All seven cases of established persistent trophoblastic disease, for which follow up was available, were diploid and showed high hyperdiploid fractions within the range for diploid complete moles. These findings suggest that flow cytometric DNA measurements may be an important aid in the diagnosis of molar pregnancy. The high degree of cell proliferation found in this study may explain the premalignant potential of complete hydatidiform moles. PMID:3611391

  19. Relative Entropy and Squashed Entanglement

    NASA Astrophysics Data System (ADS)

    Li, Ke; Winter, Andreas

    2014-02-01

    We are interested in the properties and relations of entanglement measures. Especially, we focus on the squashed entanglement and relative entropy of entanglement, as well as their analogues and variants. Our first result is a monogamy-like inequality involving the relative entropy of entanglement and its one-way LOCC variant. The proof is accomplished by exploring the properties of relative entropy in the context of hypothesis testing via one-way LOCC operations, and by making use of an argument resembling that by Piani on the faithfulness of regularized relative entropy of entanglement. Following this, we obtain a commensurate and faithful lower bound for squashed entanglement, in the form of one-way LOCC relative entropy of entanglement. This gives a strengthening to the strong subadditivity of von Neumann entropy. Our result improves the trace-distance-type bound derived in Brandão et al. (Commun Math Phys, 306:805-830, 2011), where faithfulness of squashed entanglement was first proved. Applying Pinsker's inequality, we are able to recover the trace-distance-type bound, even with slightly better constant factor. However, the main improvement is that our new lower bound can be much larger than the old one and it is almost a genuine entanglement measure. We evaluate exactly the relative entropy of entanglement under various restricted measurement classes, for maximally entangled states. Then, by proving asymptotic continuity, we extend the exact evaluation to their regularized versions for all pure states. Finally, we consider comparisons and separations between some important entanglement measures and obtain several new results on these, too.

  20. Does horizon entropy satisfy a quantum null energy conjecture?

    NASA Astrophysics Data System (ADS)

    Fu, Zicao; Marolf, Donald

    2016-12-01

    A modern version of the idea that the area of event horizons gives 4G times an entropy is the Hubeny-Rangamani causal holographic information (CHI) proposal for holographic field theories. Given a region R of a holographic QFTs, CHI computes A/4G on a certain cut of an event horizon in the gravitational dual. The result is naturally interpreted as a coarse-grained entropy for the QFT. CHI is known to be finitely greater than the fine-grained Hubeny-Rangamani-Takayanagi (HRT) entropy when \\partial R lies on a Killing horizon of the QFT spacetime, and in this context satisfies other non-trivial properties expected of an entropy. Here we present evidence that it also satisfies the quantum null energy condition (QNEC), which bounds the second derivative of the entropy of a quantum field theory on one side of a non-expanding null surface by the flux of stress-energy across the surface. In particular, we show CHI to satisfy the QNEC in 1  +  1 holographic CFTs when evaluated in states dual to conical defects in AdS3. This surprising result further supports the idea that CHI defines a useful notion of coarse-grained holographic entropy, and suggests unprecedented bounds on the rate at which bulk horizon generators emerge from a caustic. To supplement our motivation, we include an appendix deriving a corresponding coarse-grained generalized second law for 1  +  1 holographic CFTs perturbatively coupled to dilaton gravity.

  1. Entropy from State Probabilities: Hydration Entropy of Cations

    PubMed Central

    2013-01-01

    Entropy is an important energetic quantity determining the progression of chemical processes. We propose a new approach to obtain hydration entropy directly from probability density functions in state space. We demonstrate the validity of our approach for a series of cations in aqueous solution. Extensive validation of simulation results was performed. Our approach does not make prior assumptions about the shape of the potential energy landscape and is capable of calculating accurate hydration entropy values. Sampling times in the low nanosecond range are sufficient for the investigated ionic systems. Although the presented strategy is at the moment limited to systems for which a scalar order parameter can be derived, this is not a principal limitation of the method. The strategy presented is applicable to any chemical system where sufficient sampling of conformational space is accessible, for example, by computer simulations. PMID:23651109

  2. Photosynthesis and negative entropy production.

    PubMed

    Jennings, Robert C; Engelmann, Enrico; Garlaschi, Flavio; Casazza, Anna Paola; Zucchelli, Giuseppe

    2005-09-30

    The widely held view that the maximum efficiency of a photosynthetic pigment system is given by the Carnot cycle expression (1-T/Tr) for energy transfer from a hot bath (radiation at temperature Tr) to a cold bath (pigment system at temperature T) is critically examined and demonstrated to be inaccurate when the entropy changes associated with the microscopic process of photon absorption and photochemistry at the level of single photosystems are considered. This is because entropy losses due to excited state generation and relaxation are extremely small (DeltaS < T/Tr) and are essentially associated with the absorption-fluorescence Stokes shift. Total entropy changes associated with primary photochemistry for single photosystems are shown to depend critically on the thermodynamic efficiency of the process. This principle is applied to the case of primary photochemistry of the isolated core of higher plant photosystem I and photosystem II, which are demonstrated to have maximal thermodynamic efficiencies of xi > 0.98 and xi > 0.92 respectively, and which, in principle, function with negative entropy production. It is demonstrated that for the case of xi > (1-T/Tr) entropy production is always negative and only becomes positive when xi < (1-T/Tr).

  3. Towards a derivation of holographic entanglement entropy

    NASA Astrophysics Data System (ADS)

    Casini, Horacio; Huerta, Marina; Myers, Robert C.

    2011-05-01

    We provide a derivation of holographic entanglement entropy for spherical entangling surfaces. Our construction relies on conformally mapping the boundary CFT to a hyperbolic geometry and observing that the vacuum state is mapped to a thermal state in the latter geometry. Hence the conformal transformation maps the entanglement entropy to the thermodynamic entropy of this thermal state. The AdS/CFT dictionary allows us to calculate this thermodynamic entropy as the horizon entropy of a certain topological black hole. In even dimensions, we also demonstrate that the universal contribution to the entanglement entropy is given by A-type trace anomaly for any CFT, without reference to holography.

  4. Caries Management Strategies for Primary Molars

    PubMed Central

    Santamaria, R.M.; Innes, N.P.T.; Machiulskiene, V.; Evans, D.J.P.; Splieth, C.H.

    2014-01-01

    Minimal invasive approaches to managing caries, such as partial caries removal techniques, are showing increasing evidence of improved outcomes over the conventional complete caries removal. There is also increasing interest in techniques where no caries is removed. We present the 1-yr results of clinical efficacy for 3 caries management options for occlusoproximal cavitated lesions in primary molars: conventional restorations (CR; complete caries removal and compomer restoration), Hall technique (HT; no caries removal, sealing in with stainless steel crowns), and nonrestorative caries treatment (NRCT; no caries removal, opening up the cavity, teaching brushing and fluoride application). In sum, 169 children (3-8 yr old; mean, 5.56 ± 1.45 yr) were enrolled in this secondary care–based, 3-arm, parallel-group, randomized clinical trial. Treatments were carried out by specialist pediatric dentists or postgraduate trainees. One lesion per child received CR, HT, or NRCT. Outcome measures were clinical failure rates, grouped as minor failure (restoration loss/need for replacement, reversible pulpitis, caries progression, etc.) and major failure (irreversible pulpitis, abscess, etc.). There were 148 children (87.6%) with a minimum follow-up of 11 mo (mean, 12.23 ± 0.98 mo). Twenty teeth were recorded as having at least 1 minor failure: NRCT, n = 8 (5%); CR, n = 11 (7%); HT, n = 1 (1%) (p = .002, 95% CI = 0.001 to 0.003). Only the comparison between NRCT and CR showed no significant difference (p = .79, 95% CI = 0.78 to 0.80). Nine (6%) experienced at least 1 major failure: NRCT, n = 4 (2%); CR, n = 5 (3%); HT, n = 0 (0%) (p = .002, 95% CI = 0.001 to 0.003). Individual comparison of NRCT and CR showed no statistically significant difference in major failures (p = .75, 95% CI = 0.73 to 0.76). Success and failure rates were not significantly affected by pediatric dentists’ level of experience (p = .13, 95% CI = 0.12 to 0.14). The HT was significantly more successful

  5. Concentrating partial entanglement by local operations

    NASA Astrophysics Data System (ADS)

    Bennett, Charles H.; Bernstein, Herbert J.; Popescu, Sandu; Schumacher, Benjamin

    1996-04-01

    If two separated observers are supplied with entanglement, in the form of n pairs of particles in identical partly entangled pure states, one member of each pair being given to each observer, they can, by local actions of each observer, concentrate this entanglement into a smaller number of maximally entangled pairs of particles, for example, Einstein-Podolsky-Rosen singlets, similarly shared between the two observers. The concentration process asymptotically conserves entropy of entanglement-the von Neumann entropy of the partial density matrix seen by either observer-with the yield of singlets approaching, for large n, the base-2 entropy of entanglement of the initial partly entangled pure state. Conversely, any pure or mixed entangled state of two systems can be produced by two classically communicating separated observers, drawing on a supply of singlets as their sole source of entanglement.

  6. Oxygen from Hydrogen Peroxide. A Safe Molar Volume-Molar Mass Experiment.

    ERIC Educational Resources Information Center

    Bedenbaugh, John H.; And Others

    1988-01-01

    Describes a molar volume-molar mass experiment for use in general chemistry laboratories. Gives background technical information, procedures for the titration of aqueous hydrogen peroxide with standard potassium permanganate and catalytic decomposition of hydrogen peroxide to produce oxygen, and a discussion of the results obtained in three…

  7. Oxygen from Hydrogen Peroxide. A Safe Molar Volume-Molar Mass Experiment.

    ERIC Educational Resources Information Center

    Bedenbaugh, John H.; And Others

    1988-01-01

    Describes a molar volume-molar mass experiment for use in general chemistry laboratories. Gives background technical information, procedures for the titration of aqueous hydrogen peroxide with standard potassium permanganate and catalytic decomposition of hydrogen peroxide to produce oxygen, and a discussion of the results obtained in three…

  8. Orthodontic extrusion of horizontally impacted mandibular molars

    PubMed Central

    Ma, Zhigui; Yang, Chi; Zhang, Shanyong; Xie, Qianyang; Shen, Yuqing; Shen, Pei

    2014-01-01

    Objective: To introduce and evaluate a novel approach in treating horizontally impacted mandibular second and third molars. Materials and methods: An orthodontic technique was applied for treatment of horizontally impacted mandibular second and third molars, which included a push-type spring for rotation first, and then a cantilever for extrusion. There were 8 mandibular third molars (M3s) and 2 second molars (M2s) in this study. Tooth mobility, extraction time, the inclination and parallelism of the impacted tooth, alveolar bone height of the adjacent tooth, and the relationship of impacted M3 and the inferior alveolar nerve (IAN) were evaluated. Results: Two horizontally impacted M2s could be upright in the arch and good occlusal relationships were obtained after treatment. All impacted M3s were successfully separated from the IAN, without any neurologic consequences. The average extraction time was 5 minutes. There was a significant change in the inclination and parallelism of the impacted tooth after treatment. A new bone apposition with the average height of 3.2 mm was noted distal to the adjacent tooth. Conclusions: This two-step orthodontic technique as presented here may be a safe and feasible alternative in management of severely horizontally impacted mandibular molars, which achieves a successful separation of M3s from the IAN and an excellent position for M2s. PMID:25419364

  9. Convex Accelerated Maximum Entropy Reconstruction

    PubMed Central

    Worley, Bradley

    2016-01-01

    Maximum entropy (MaxEnt) spectral reconstruction methods provide a powerful framework for spectral estimation of nonuniformly sampled datasets. Many methods exist within this framework, usually defined based on the magnitude of a Lagrange multiplier in the MaxEnt objective function. An algorithm is presented here that utilizes accelerated first-order convex optimization techniques to rapidly and reliably reconstruct nonuniformly sampled NMR datasets using the principle of maximum entropy. This algorithm – called CAMERA for Convex Accelerated Maximum Entropy Reconstruction Algorithm – is a new approach to spectral reconstruction that exhibits fast, tunable convergence in both constant-aim and constant-lambda modes. A high-performance, open source NMR data processing tool is described that implements CAMERA, and brief comparisons to existing reconstruction methods are made on several example spectra. PMID:26894476

  10. Wavelet entropy of stochastic processes

    NASA Astrophysics Data System (ADS)

    Zunino, L.; Pérez, D. G.; Garavaglia, M.; Rosso, O. A.

    2007-06-01

    We compare two different definitions for the wavelet entropy associated to stochastic processes. The first one, the normalized total wavelet entropy (NTWS) family [S. Blanco, A. Figliola, R.Q. Quiroga, O.A. Rosso, E. Serrano, Time-frequency analysis of electroencephalogram series, III. Wavelet packets and information cost function, Phys. Rev. E 57 (1998) 932-940; O.A. Rosso, S. Blanco, J. Yordanova, V. Kolev, A. Figliola, M. Schürmann, E. Başar, Wavelet entropy: a new tool for analysis of short duration brain electrical signals, J. Neurosci. Method 105 (2001) 65-75] and a second introduced by Tavares and Lucena [Physica A 357(1) (2005) 71-78]. In order to understand their advantages and disadvantages, exact results obtained for fractional Gaussian noise ( -1<α< 1) and fractional Brownian motion ( 1<α< 3) are assessed. We find out that the NTWS family performs better as a characterization method for these stochastic processes.

  11. Conditional entropy and Landauer principle

    NASA Astrophysics Data System (ADS)

    Chiuchiú, D.; Diamantini, M. C.; Gammaitoni, L.

    2015-08-01

    The Landauer principle describes the minimum heat produced by an information-processing device. Recently a new term has been included in the minimum heat production: it is called conditional entropy and takes into account the microstates content of a given logic state. Usually this term is assumed to be zero in bistable symmetric systems thanks to the strong hypothesis used to derive the Landauer principle. In this paper we show that conditional entropy can be nonzero even for bistable symmetric systems and that it can be expressed as the sum of three different terms related to the probabilistic features of the device. The contribution of the three terms to conditional entropy (and thus to the minimum heat production) is then discussed for the case of bit reset.

  12. Quantum geometry and gravitational entropy

    SciTech Connect

    Simon, Joan; Balasubramanian, Vijay; Czech, Bart Iomiej; Larjo, Klaus; Marolf, Donald; Simon, Joan

    2007-05-29

    Most quantum states have wavefunctions that are widely spread over the accessible Hilbert space and hence do not have a good description in terms of a single classical geometry. In order to understand when geometric descriptions are possible, we exploit the AdS/CFT correspondence in the half-BPS sector of asymptotically AdS_5 x S5 universes. In this sector we devise a"coarse-grained metric operator" whose eigenstates are well described by a single spacetime topology and geometry. We show that such half-BPS universes have a non-vanishing entropy if and only if the metric is singular, and that the entropy arises from coarse-graining the geometry. Finally, we use our entropy formula to find the most entropic spacetimes with fixed asymptotic moments beyond the global charges.

  13. Relative Entropy and Torsion Coupling

    NASA Astrophysics Data System (ADS)

    Lin, Feng-Li; Ning, Bo

    2017-08-01

    Based on the the geometric realization of entanglement entropy via Ryu-Takayanagi formula, in this work we evaluate the relative entropy for the holographic deformed CFT dual to the torsion gravity coupled to the fermions of nonzero vev in the Einstein-Cartan formulation. We find that the positivity and monotonicity of the relative entropy imposes constraint on the strength of axial-current coupling, fermion mass and equation of state. Our work is the first example to demonstrate the nontrivial constraint on the bulk gravity theory from the quantum information inequalities. Especially, this constraint is beyond the symmetry action principle and should be understood as the unitarity constraint. This talk is based on the work [1] of the authors.

  14. Convex accelerated maximum entropy reconstruction.

    PubMed

    Worley, Bradley

    2016-04-01

    Maximum entropy (MaxEnt) spectral reconstruction methods provide a powerful framework for spectral estimation of nonuniformly sampled datasets. Many methods exist within this framework, usually defined based on the magnitude of a Lagrange multiplier in the MaxEnt objective function. An algorithm is presented here that utilizes accelerated first-order convex optimization techniques to rapidly and reliably reconstruct nonuniformly sampled NMR datasets using the principle of maximum entropy. This algorithm - called CAMERA for Convex Accelerated Maximum Entropy Reconstruction Algorithm - is a new approach to spectral reconstruction that exhibits fast, tunable convergence in both constant-aim and constant-lambda modes. A high-performance, open source NMR data processing tool is described that implements CAMERA, and brief comparisons to existing reconstruction methods are made on several example spectra. Copyright © 2016 Elsevier Inc. All rights reserved.

  15. Convex accelerated maximum entropy reconstruction

    NASA Astrophysics Data System (ADS)

    Worley, Bradley

    2016-04-01

    Maximum entropy (MaxEnt) spectral reconstruction methods provide a powerful framework for spectral estimation of nonuniformly sampled datasets. Many methods exist within this framework, usually defined based on the magnitude of a Lagrange multiplier in the MaxEnt objective function. An algorithm is presented here that utilizes accelerated first-order convex optimization techniques to rapidly and reliably reconstruct nonuniformly sampled NMR datasets using the principle of maximum entropy. This algorithm - called CAMERA for Convex Accelerated Maximum Entropy Reconstruction Algorithm - is a new approach to spectral reconstruction that exhibits fast, tunable convergence in both constant-aim and constant-lambda modes. A high-performance, open source NMR data processing tool is described that implements CAMERA, and brief comparisons to existing reconstruction methods are made on several example spectra.

  16. Construction of microcanonical entropy on thermodynamic pillars.

    PubMed

    Campisi, Michele

    2015-05-01

    A question that is currently highly debated is whether the microcanonical entropy should be expressed as the logarithm of the phase volume (volume entropy, also known as the Gibbs entropy) or as the logarithm of the density of states (surface entropy, also known as the Boltzmann entropy). Rather than postulating them and investigating the consequence of each definition, as is customary, here we adopt a bottom-up approach and construct the entropy expression within the microcanonical formalism upon two fundamental thermodynamic pillars: (i) The second law of thermodynamics as formulated for quasistatic processes: δQ/T is an exact differential, and (ii) the law of ideal gases: PV=k(B)NT. The first pillar implies that entropy must be some function of the phase volume Ω. The second pillar singles out the logarithmic function among all possible functions. Hence the construction leads uniquely to the expression S=k(B)lnΩ, that is, the volume entropy. As a consequence any entropy expression other than that of Gibbs, e.g., the Boltzmann entropy, can lead to inconsistencies with the two thermodynamic pillars. We illustrate this with the prototypical example of a macroscopic collection of noninteracting spins in a magnetic field, and show that the Boltzmann entropy severely fails to predict the magnetization, even in the thermodynamic limit. The uniqueness of the Gibbs entropy, as well as the demonstrated potential harm of the Boltzmann entropy, provide compelling reasons for discarding the latter at once.

  17. Construction of microcanonical entropy on thermodynamic pillars

    NASA Astrophysics Data System (ADS)

    Campisi, Michele

    2015-05-01

    A question that is currently highly debated is whether the microcanonical entropy should be expressed as the logarithm of the phase volume (volume entropy, also known as the Gibbs entropy) or as the logarithm of the density of states (surface entropy, also known as the Boltzmann entropy). Rather than postulating them and investigating the consequence of each definition, as is customary, here we adopt a bottom-up approach and construct the entropy expression within the microcanonical formalism upon two fundamental thermodynamic pillars: (i) The second law of thermodynamics as formulated for quasistatic processes: δ Q /T is an exact differential, and (ii) the law of ideal gases: P V =kBN T . The first pillar implies that entropy must be some function of the phase volume Ω . The second pillar singles out the logarithmic function among all possible functions. Hence the construction leads uniquely to the expression S =kBlnΩ , that is, the volume entropy. As a consequence any entropy expression other than that of Gibbs, e.g., the Boltzmann entropy, can lead to inconsistencies with the two thermodynamic pillars. We illustrate this with the prototypical example of a macroscopic collection of noninteracting spins in a magnetic field, and show that the Boltzmann entropy severely fails to predict the magnetization, even in the thermodynamic limit. The uniqueness of the Gibbs entropy, as well as the demonstrated potential harm of the Boltzmann entropy, provide compelling reasons for discarding the latter at once.

  18. Comparative evaluation of molar distalization therapy with erupted second molar: Segmented versus Quad Pendulum appliance.

    PubMed

    Caprioglio, Alberto; Cozzani, Mauro; Fontana, Mattia

    2014-01-01

    There are controversial opinions about the effect of erupted second molars on distalization of the first molars. Most of the distalizing devices are anchored on the first molars, without including second molars; so, differences between sequentially distalize maxillary molars (second molar followed by the first molar) or distalize second and first molars together are not clear. The aim of the study was to compare sequential versus simultaneous molar distalization therapy with erupted second molar using two different modified Pendulum appliances followed by fixed appliances. The treatment sample consisted of 35 class II malocclusion subjects, divided in two groups: group 1 consisted of 24 patients (13 males and 11 females) with a mean pre-treatment age of 12.9 years, treated with the Segmented Pendulum (SP) and fixed appliances; group 2 consisted of 11 patients (6 males and 5 females) with a mean pre-treatment age of 13.2 years, treated with the Quad Pendulum (QP) and fixed appliances. Lateral cephalograms were obtained before treatment (T1), at the end of distalization (T2), and at the end of orthodontic fixed appliance therapy (T3). A Student t test was used to identify significant between-group differences between T1 to T2, T2 to T3, and T1 to T3. QP and SP were equally effective in distalizing maxillary molars (3.5 and 4 mm, respectively) between T1 and T2; however, the maxillary first molar showed less distal tipping (4.6° vs. 9.6°) and more extrusion (1.1 vs. 0.2 mm) in the QP group than in the SP group, as well as the vertical facial dimension, which increased more in the QP group (1.2°) than in the SP group (0.7°). At T3, the QP group maintained greater increase in lower anterior facial height and molar extrusion and decrease in overbite than the SP group. Quad Pendulum seems to have greater increase in vertical dimension and molar extrusion than the Segmented Pendulum.

  19. Molar heat capacity and molar excess enthalpy measurements in aqueous amine solutions

    NASA Astrophysics Data System (ADS)

    Poozesh, Saeed

    Experimental measurements of molar heat capacity and molar excess enthalpy for 1, 4-dimethyl piperazine (1, 4-DMPZ), 1-(2-hydroxyethyl) piperazine (1, 2-HEPZ), I-methyl piperazine (1-MPZ), 3-morpholinopropyl amine (3-MOPA), and 4-(2-hydroxy ethyl) morpholine (4, 2-HEMO) aqueous solutions were carried out in a C80 heat flow calorimeter over a range of temperatures from (298.15 to 353.15) K and for the entire range of the mole fractions. The estimated uncertainty in the measured values of the molar heat capacity and molar excess enthalpy was found to be +/- 2%. Among the five amines studied, 3-MOPA had the highest values of the molar heat capacity and 1-MPZ the lowest. Values of molar heat capacities of amines were dominated by --CH 2, --N, --OH, --O, --NH2 groups and increased with increasing temperature, and contributions of --NH and --CH 3 groups decreased with increasing temperature for these cyclic amines. Molar excess heat capacities were calculated from the measured molar heat capacities and were correlated as a function of the mole fractions employing the Redlich-Kister equation. The molar excess enthalpy values were also correlated as a function of the mole fractions employing the Redlich-Kister equation. Molar enthalpies at infinite dilution were derived. Molar excess enthalpy values were modeled using the solution theory models: NRTL (Non Random Two Liquid) and UNIQUAC (UNIversal QUAsi Chemical) and the modified UNIFAC (UNIversal quasi chemical Functional group Activity Coefficients - Dortmund). The modified UNIFAC was found to be the most accurate and reliable model for the representation and prediction of the molar excess enthalpy values. Among the five amines, the 1-MPZ + water system exhibited the highest values of molar excess enthalpy on the negative side. This study confirmed the conclusion made by Maham et al. (71) that -CH3 group contributed to higher molar excess enthalpies. The negative excess enthalpies were reduced due to the contribution of

  20. Traffic network and distribution of cars: Maximum-entropy approach

    SciTech Connect

    Das, N.C.; Chakrabarti, C.G.; Mazumder, S.K.

    2000-02-01

    An urban transport system plays a vital role in the modeling of the modern cosmopolis. A great emphasis is needed for the proper development of a transport system, particularly the traffic network and flow, to meet possible future demand. There are various mathematical models of traffic network and flow. The role of Shannon entropy in the modeling of traffic network and flow was stressed by Tomlin and Tomlin (1968) and Tomlin (1969). In the present note the authors study the role of maximum-entropy principle in the solution of an important problem associated with the traffic network flow. The maximum-entropy principle initiated by Jaynes is a powerful optimization technique of determining the distribution of a random system in the case of partial or incomplete information or data available about the system. This principle has now been broadened and extended and has found wide applications in different fields of science and technology. In the present note the authors show how the Jaynes' maximum-entropy principle, slightly modified, can be successfully applied in determining the flow or distribution of cars in different paths of a traffic network when incomplete information is available about the network.

  1. Information and Entropy Flow in the Kalman?Bucy Filter

    NASA Astrophysics Data System (ADS)

    Mitter, Sanjoy K.; Newton, Nigel J.

    2005-01-01

    We investigate the information theoretic properties of Kalman-Bucy filters in continuous time, developing notions of information supply, storage and dissipation. Introducing a concept of energy, we develop a physical analogy in which the unobserved signal describes a statistical mechanical system interacting with a heat bath. The abstract `universe' comprising the signal and the heat bath obeys a non-increase law of entropy; however, with the introduction of partial observations, this law can be violated. The Kalman-Bucy filter behaves like a Maxwellian demon in this analogy, returning signal energy to the heat bath without causing entropy increase. This is made possible by the steady supply of new information. In a second analogy the signal and filter interact, setting up a stationary non-equilibrium state, in which energy flows between the heat bath, the signal and the filter without causing any overall entropy increase. We introduce a rate of interactive entropy flow that isolates the statistical mechanics of this flow from marginal effects. Both analogies provide quantitative examples of Landauer's Principle.

  2. Conformational Entropy of Intrinsically Disordered Proteins from Amino Acid Triads

    PubMed Central

    Baruah, Anupaul; Rani, Pooja; Biswas, Parbati

    2015-01-01

    This work quantitatively characterizes intrinsic disorder in proteins in terms of sequence composition and backbone conformational entropy. Analysis of the normalized relative composition of the amino acid triads highlights a distinct boundary between globular and disordered proteins. The conformational entropy is calculated from the dihedral angles of the middle amino acid in the amino acid triad for the conformational ensemble of the globular, partially and completely disordered proteins relative to the non-redundant database. Both Monte Carlo (MC) and Molecular Dynamics (MD) simulations are used to characterize the conformational ensemble of the representative proteins of each group. The results show that the globular proteins span approximately half of the allowed conformational states in the Ramachandran space, while the amino acid triads in disordered proteins sample the entire range of the allowed dihedral angle space following Flory’s isolated-pair hypothesis. Therefore, only the sequence information in terms of the relative amino acid triad composition may be sufficient to predict protein disorder and the backbone conformational entropy, even in the absence of well-defined structure. The predicted entropies are found to agree with those calculated using mutual information expansion and the histogram method. PMID:26138206

  3. The entropy of Black Shells

    NASA Astrophysics Data System (ADS)

    Rojas C., W. A.; Arenas S., R.

    2017-07-01

    The formalism of Darmois-Israel is used to calculate the entropy of a thin spherical shell that contracts from infinity down to near its gravitational radius. It was found that the entropy contained in the thin shell is proportional to the horizon area depending on the number of species N, the distance own above the horizon α and two constants C1 and C2 which can be measured observationally. Certain thermodynamic parameters were calculated, when thin shell it is near the horizon of events for a static space-time, this parameters are agree with reported.

  4. Maximum Entropy Guide for BSS

    NASA Astrophysics Data System (ADS)

    Górriz, J. M.; Puntonet, C. G.; Medialdea, E. G.; Rojas, F.

    2005-11-01

    This paper proposes a novel method for Blindly Separating unobservable independent component (IC) Signals (BSS) based on the use of a maximum entropy guide (MEG). The paper also includes a formal proof on the convergence of the proposed algorithm using the guiding operator, a new concept in the genetic algorithm (GA) scenario. The Guiding GA (GGA) presented in this work, is able to extract IC with faster rate than the previous ICA algorithms, based on maximum entropy contrast functions, as input space dimension increases. It shows significant accuracy and robustness than the previous approaches in any case.

  5. 40 CFR Table 1 to Subpart Ja of... - Molar Exhaust Volumes and Molar Heat Content of Fuel Gas Constituents

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 7 2014-07-01 2014-07-01 false Molar Exhaust Volumes and Molar Heat... Exhaust Volumes and Molar Heat Content of Fuel Gas Constituents Constituent MEVa dscf/mol MHCb Btu/mol... standard conditions of 68 °F and 1 atmosphere. b MHC = molar heat content (higher heating value basis), Btu...

  6. 40 CFR Table 1 to Subpart Ja of... - Molar Exhaust Volumes and Molar Heat Content of Fuel Gas Constituents

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 7 2013-07-01 2013-07-01 false Molar Exhaust Volumes and Molar Heat... Exhaust Volumes and Molar Heat Content of Fuel Gas Constituents Constituent MEVa dscf/mol MHCb Btu/mol... standard conditions of 68 °F and 1 atmosphere. b MHC = molar heat content (higher heating value basis), Btu...

  7. Ordering Transformations in High-Entropy Alloys

    NASA Astrophysics Data System (ADS)

    Singh, Prashant; Johnson, Duane D.

    The high-temperature disordered phase of multi-component alloys, including high-entropy alloys (HEA), generally must experience segregation or else passes through partially-ordered phases to reach the low-temperature, fully-ordered phase. Our first-principles KKR-CPA-based atomic short-range ordering (SRO) calculations (analyzed as concentration-waves) reveal the competing partially and fully ordered phases in HEA, and these phases can be then directly assessed from KKR-CPA results in larger unit cells [Phys. Rev. B 91, 224204 (2015)]. For AlxCrFeNiTi0.25, Liu et al. [J Alloys Compd 619, 610 (2015)] experimentally find FCC+BCC coexistence that changes to BCC with increasing Al (x from 0-to-1), which then exhibits a partially-ordered B2 at low temperatures. CALPHAD (Calculation of Phase Diagrams) predicts a region with L21+B2 coexistence. From KKR-CPA calculations, we find crossover versus Al from FCC+BCC coexistence to BCC, as observed, and regions for partially-order B2+L21 coexistence, as suggest by CALPHAD. Our combined first-principles KKR-CPA method provides a powerful approach in predicting SRO and completing long-range order in HEA and other complex alloys. Supported by the U.S. DOE, Office of Science, Basic Energy Sciences, Materials Science and Engineering Division. Work was performed at Ames Laboratory, which is operated by Iowa State University for the U.S. DOE under Contract #DE-AC02-07CH11358.

  8. Partial Tonsillectomy.

    PubMed

    Wong, Kevin; Levi, Jessica R

    2017-03-01

    Evaluate the content and readability of health information regarding partial tonsillectomy. A web search was performed using the term partial tonsillectomy in Google, Yahoo!, and Bing. The first 50 websites from each search were evaluated using HONcode standards for quality and content. Readability was assessed using the Flesch-Kincaid Grade Level (FKGL), Flesch Reading Ease, Gunning-Fog Index, Coleman-Liau Index, Automated Readability Index, and SMOG score. The Freeman-Halton extension of Fisher's exact test was used to compare categorical differences between engines. Less than half of the websites mentioned patient eligibility criteria (43.3%), referenced peer-reviewed literature (43.3%), or provided a procedure description (46.7%). Twenty-two websites (14.7%) were unrelated to partial tonsillectomy, and over half contained advertisements (52%). These finding were consistent across search engines and search terms. The mean FKGL was 11.6 ± 0.11, Gunning-Fog Index was 15.1 ± 0.13, Coleman-Liau Index was 14.6 ± 0.11, ARI was 12.9 ± 0.13, and SMOG grade was 14.0 ± 0.1. All readability levels exceeded the abilities of the average American adult. Current online information regarding partial tonsillectomy may not provide adequate information and may be written at a level too difficult for the average adult reader.

  9. Fabrication and Evaluation of a Noncompliant Molar Distalizing Appliance: Bonded Molar Distalizer

    PubMed Central

    Sodagar, A.; Ahmad Akhoundi, M. S.; Rafighii, A.; Arab, S.

    2011-01-01

    Objective Attempts to treat class II malocclusions without extraction in non-compliant patients have led to utilization of intraoral molar distalizing appliances. The purpose of this study was to investigate dental and skeletal effects of Bonded Molar Distalizer (BMD) which is a simple molar distalizing appliance. Materials and Methods Sixteen patients (12 girls, four boys) with bilateral half-cusp class II molar relationship, erupted permanent second molars and normal or vertical growth pattern were selected for bilateral distalization of maxillary molars via BMD. The screws were activated every other day, alternately. Lateral cephalograms and study models were obtained before treatment and after 11 weeks activation of the appliance. Results Significant amounts of molar distalization, molar distal tipping and anchorage loss were observed. The mean maxillary first molar distal movement was 1.22±0.936 mm with a distal tipping of 2.97±3.74 degrees in 11 weeks. The rate of distal movement was 0.48 mm per month. Reciprocal mesial movement of the first premolars was 2.26±1.12 mm with a mesial tipping of 4.25±3.12 degrees. Maxillary incisors moved 3.55±1.46 mm and tipped 9.87±5.03 degrees mesially. Lower anterior face height (LAFH) decreased 1.28±1.36 mm. Conclusion BMD is appropriate for distalizing maxillary molars, especially in patients with critical LAFH, although significant amounts of anchorage loss occur using this appliance. PMID:22457837

  10. Discrete state model and accurate estimation of loop entropy of RNA secondary structures.

    PubMed

    Zhang, Jian; Lin, Ming; Chen, Rong; Wang, Wei; Liang, Jie

    2008-03-28

    Conformational entropy makes important contribution to the stability and folding of RNA molecule, but it is challenging to either measure or compute conformational entropy associated with long loops. We develop optimized discrete k-state models of RNA backbone based on known RNA structures for computing entropy of loops, which are modeled as self-avoiding walks. To estimate entropy of hairpin, bulge, internal loop, and multibranch loop of long length (up to 50), we develop an efficient sampling method based on the sequential Monte Carlo principle. Our method considers excluded volume effect. It is general and can be applied to calculating entropy of loops with longer length and arbitrary complexity. For loops of short length, our results are in good agreement with a recent theoretical model and experimental measurement. For long loops, our estimated entropy of hairpin loops is in excellent agreement with the Jacobson-Stockmayer extrapolation model. However, for bulge loops and more complex secondary structures such as internal and multibranch loops, we find that the Jacobson-Stockmayer extrapolation model has large errors. Based on estimated entropy, we have developed empirical formulae for accurate calculation of entropy of long loops in different secondary structures. Our study on the effect of asymmetric size of loops suggest that loop entropy of internal loops is largely determined by the total loop length, and is only marginally affected by the asymmetric size of the two loops. Our finding suggests that the significant asymmetric effects of loop length in internal loops measured by experiments are likely to be partially enthalpic. Our method can be applied to develop improved energy parameters important for studying RNA stability and folding, and for predicting RNA secondary and tertiary structures. The discrete model and the program used to calculate loop entropy can be downloaded at http://gila.bioengr.uic.edu/resources/RNA.html.

  11. Diagnosis and treatment of molar incisor hypomineralization.

    PubMed

    Mathu-Muju, Kavita; Wright, J Timothy

    2006-11-01

    Molar incisor hypomineralization (MIH) is a relatively common condition that varies in clinical severity and can result in early loss of the permanent 6-year molars. The etiology of MIH remains unclear, and the diagnosis can be confused with more generalized enamel defects such as those that occur in amelogenesis imperfecta. The management of MIH depends largely on the severity of the enamel defect. Degrees of hypomineralization can range from mild enamel opacities to enamel that readily abrades from the tooth as it emerges into the oral cavity. Usually, severely affected molars are extremely hypersensitive, prone to rapid caries development, and can be difficult to manage in young patients. The purpose of this article is to review approaches to diagnosing and treating MIH.

  12. Lower third molar eruption following orthodontic treatment.

    PubMed

    Salehi, P; Danaie, S Momene

    2008-01-01

    This study assessed the effect of extraction and preservation of the 1st premolar on lower 3rd molar eruption. Orthodontic clinic records from 1993 to 1995 were evaluated before and after treatment and 8-9 years after treatment for 3 groups of patients: 32 with extraction of 1st premolars in both jaws, 32 with no extraction but orthodontic treatment and 48 controls with no extraction but orthodontic treatment in the upper jaws only. Successful eruption of 3rd molars was evaluated. There was a significant difference in the rates of successful eruptions in the extraction (42%), non-extraction (12%) and control (20%) groups. The findings indicate that 1st premolar extraction may increase the chance of 3rd molar eruption, leading to a lower incidence of health and economic complications.

  13. Using entropy measures to characterize human locomotion.

    PubMed

    Leverick, Graham; Szturm, Tony; Wu, Christine Q

    2014-12-01

    Entropy measures have been widely used to quantify the complexity of theoretical and experimental dynamical systems. In this paper, the value of using entropy measures to characterize human locomotion is demonstrated based on their construct validity, predictive validity in a simple model of human walking and convergent validity in an experimental study. Results show that four of the five considered entropy measures increase meaningfully with the increased probability of falling in a simple passive bipedal walker model. The same four entropy measures also experienced statistically significant increases in response to increasing age and gait impairment caused by cognitive interference in an experimental study. Of the considered entropy measures, the proposed quantized dynamical entropy (QDE) and quantization-based approximation of sample entropy (QASE) offered the best combination of sensitivity to changes in gait dynamics and computational efficiency. Based on these results, entropy appears to be a viable candidate for assessing the stability of human locomotion.

  14. Entropy Analyses of Four Familiar Processes.

    ERIC Educational Resources Information Center

    Craig, Norman C.

    1988-01-01

    Presents entropy analysis of four processes: a chemical reaction, a heat engine, the dissolution of a solid, and osmosis. Discusses entropy, the second law of thermodynamics, and the Gibbs free energy function. (MVL)

  15. Entropy Analyses of Four Familiar Processes.

    ERIC Educational Resources Information Center

    Craig, Norman C.

    1988-01-01

    Presents entropy analysis of four processes: a chemical reaction, a heat engine, the dissolution of a solid, and osmosis. Discusses entropy, the second law of thermodynamics, and the Gibbs free energy function. (MVL)

  16. Periodic Trends for the Entropy of Elements.

    ERIC Educational Resources Information Center

    Thoms, Travis

    1995-01-01

    Explores the periodic trends in the entropy of elements. Focuses on concepts understandable to high school and beginning chemists. Concludes that entropy values increase with a period and generally decrease toward the center of a period. (JRH)

  17. Molar and molecular views of choice.

    PubMed

    Baum, William M

    2004-06-30

    The molar and molecular views of behavior are not different theories or levels of analysis; they are different paradigms. The molecular paradigm views behavior as composed of discrete units (responses) occurring at moments in time and strung together in chains to make up complex performances. The discrete pieces are held together as a result of association by contiguity. The molecular view has a long history both in early thought about reflexes and in associationism, and, although it was helpful to getting a science of behavior started, it has outlived its usefulness. The molar view stems from a conviction that behavior is continuous, as argued by John Dewey, Gestalt psychologists, Karl Lashley, and others. The molar paradigm views behavior as inherently extended in time and composed of activities that have integrated parts. In the molar paradigm, activities vary in their scale of organization--i.e., as to whether they are local or extended--and behavior may be controlled sometimes by short-term relations and sometimes by long-term relations. Applied to choice, the molar paradigm rests on two simple principles: (a) all behavior constitutes choice; and (b) all activities take time. Equivalence between choice and behavior occurs because every situation contains more than one alternative activity. The principle that behavior takes time refers not simply to any notion of response duration, but to the necessity that identifying one action or another requires a sample extended in time. The molecular paradigm's momentary responses are inferred from extended samples in retrospect. In this sense, momentary responses constitute abstractions, whereas extended activities constitute concrete particulars. Explanations conceived within the molecular paradigm invariably involve hypothetical constructs, because they require causes to be contiguous with responses. Explanations conceived within the molar paradigm retain direct contact with observable variables.

  18. Entropy of a vacuum: What does the covariant entropy count?

    NASA Astrophysics Data System (ADS)

    Nomura, Yasunori; Weinberg, Sean J.

    2014-11-01

    We argue that a unitary description of the formation and evaporation of a black hole implies that the Bekenstein-Hawking entropy is the "entropy of a vacuum": the logarithm of the number of possible independent ways in which quantum field theory on a fixed classical spacetime background can emerge in a full quantum theory of gravity. In many cases, the covariant entropy counts this entropy—the degeneracy of emergent quantum field theories in full quantum gravity—with the entropy of particle excitations in each quantum field theory giving only a tiny perturbation. In the Rindler description of a (black hole) horizon, the relevant vacuum degrees of freedom manifest themselves as an extra hidden quantum number carried by the states representing the second exterior region; this quantum number is invisible in the emergent quantum field theory. In a distant picture, these states arise as exponentially degenerate ground and excited states of the intrinsically quantum gravitational degrees of freedom on the stretched horizon. The formation and evaporation of a black hole involve processes in which the entropy of collapsing matter is transformed into that of a vacuum and then to that of final-state Hawking radiation. In the intermediate stage of this evolution, entanglement between the vacuum and (early) Hawking radiation develops, which is transferred to the entanglement among final-state Hawking quanta through the evaporation process. The horizon is kept smooth throughout the evolution; in particular, no firewall develops. Similar considerations also apply for cosmological horizons, for example for the horizon of a metastable de Sitter space.

  19. Investigation on the utility of permanent maxillary molar cusp areas for sex estimation.

    PubMed

    Macaluso, P James

    2011-09-01

    Digital photogrammetric methods were employed to assess the level of sexual dimorphism present in permanent maxillary molar cusp areas of black South Africans (130 males, 105 females). Odontometric standards were then developed for diagnosing sex, based on the cusp area data derived for these teeth. Results demonstrated that all cusp area measurements of both the first and second maxillary molars were significantly dimorphic (P < 0.0001) in this group. Univariate and multivariate discriminant function analyses yielded overall sex prediction accuracy rates between 59.6 and 74.5%. Comparable allocation results were also obtained for binary logistic regression analyses, but with larger classification sex biases. The highest classification accuracies were observed for different combinations of just two cusp areas for the first molar. Allocation rates of formulae derived for second molar dimensions were on average 4.3% lower than those obtained for the first molar. Analyses incorporating cusp areas of both maxillary molars did not improve classification accuracies achieved when only using first molar measurements. The classification rates are below the suggested minimum accuracy of 75-80% for reliable forensic application of a method; however, the derived formulae may provide a useful statistical indication as to the sex of fragmentary remains in which complete or even partial tooth crowns are the only materials available for examination. Furthermore, the formulae can be applied not only to adults but also to subadults (above the age of 3 years) in which the more accurate sex discriminating features of the pelvis and skull are yet to develop.

  20. Radiographic findings on 3rd molars removed in 20-year-old men.

    PubMed

    Rajasuo, Ari; Peltola, Jaakko; Ventä, Irja; Murtomaa, Heikki

    2003-10-01

    In this study we assess radiographic findings characteristic of mandibular 3rd molars that had required either routine or surgical extraction. X-ray findings relating to acute pericoronitis were also examined. The material was collected by investigating patient records and rotational panoramic radiographs of 20-year-old Finnish male conscripts (n = 738) treated during military service because of 3rd-molar-related problems. The follicle around the crown of mandibular 3rd molars with acute pericoronitis was enlarged in 19% of cases and in 13% of chronic symptom-free pericoronitis cases (not statistically significant difference). Mandibular 3rd molars extracted surgically were more often mesially inclined than those extracted routinely (61% vs. 23%; P < 0.001), partially or totally intrabony impacted (92% vs. 66%; P < 0.001) and deep situated (on average 4.2 mm vs. 2.5 mm under the occlusal plane). Surgical extraction was also associated with the roots completely developed [92% vs. 84% of the teeth routinely extracted, odds ratio (OR) 2.6, 95% confidence interval (CI) 1.2-5.5] and with the absence of radiographic pericoronitis [around 27% vs. 39% of the teeth routinely extracted (OR 0.5, 95% CI 0.3-0.8)]. In 86% of cases the space between 2nd molar and ramus of the mandible was narrower than the 3rd molar extracted surgically, whereas this was 62% in routine extraction cases (P < 0.001). We conclude that there are some typical 3rd-molar findings in rotational panoramic radiographs that show a need for surgical extraction.

  1. On the entropy variations and the Maxwell relations

    NASA Astrophysics Data System (ADS)

    Zadehgol, Abed; Ashrafizaadeh, Mahmud

    In the present work, it is shown that the Maxwell relations can effectively be used to partially verify the thermodynamic consistency of the entropic lattice kinetic models. As an example, we consider the Constant Speed Kinetic Model (CSKM) which has recently been introduced in [J. Comp. Phys. 274, 803 (2014); Phys Rev. E 91, 063311 (2015)] and show that, for the quasi-equilibrium flows and at low Mach numbers, the entropy variations are proportional to the pressure variations. The entropy variations of the CSKM are logarithmic (given by the Burg entropy) while the pressure variations obey a nonlogarithmic equation of state. The proportionality of these variations, which is in accordance with the Maxwell relations, can be used to partially verify the thermodynamic consistency of the model. A similar treatment of the previously introduced entropic lattice kinetic models (e.g. of the conventional ELBM of [I. V. Karlin, A. Ferrante and H. C. Öttinger, Europhys. Lett. 47, 182 (1999)]), can provide a new ground for comparing the thermodynamic consistency of the existing entropic lattice kinetic models with each other.

  2. The Diagnosis of Choriocarcinoma in Molar Pregnancies: A Revised Approach in Clinical Testing

    PubMed Central

    Duffy, Lisa; Zhang, Liangtao; Sheath, Karen; Love, Donald R.; George, Alice M.

    2015-01-01

    Background Hydatidiform moles occur in approximately 1 in 1,500 pregnancies; however, early miscarriages or spontaneous abortions may not be correctly identified as molar pregnancies due to poor differentiation of chorionic villi. Methods The current clinical testing algorithm used for the detection of hydatidiform moles uses a combination of morphological analysis and p57 immunostaining followed by ploidy testing to establish a diagnosis of either a complete or partial molar pregnancy. We review here 198 referrals for fluorescence in situ hybridization (FISH) ploidy testing, where the initial diagnosis based on morphology is compared to the final diagnosis based on a combination of morphology, FISH and p57 immunohistochemical (IHC) staining. Results Approximately 40% of cases were determined to be genetically abnormal, but only 28.8% of cases were diagnosed as molar pregnancies. The underestimation of complete molar pregnancies and those with androgenetic inheritance was also found to be likely using conventional diagnostic methods, as atypical p57 staining was observed in approximately 10% of cases. Conclusions Our findings suggest that a revised approach to testing products of conception is necessary, with cases screened according to their clinical history in order to distinguish molar pregnancy referrals from hydropic pregnancies. PMID:26566410

  3. Remainder terms for some quantum entropy inequalities

    SciTech Connect

    Carlen, Eric A.; Lieb, Elliott H.

    2014-04-15

    We consider three von Neumann entropy inequalities: subadditivity; Pinsker's inequality for relative entropy; and the monotonicity of relative entropy. For these we state conditions for equality, and we prove some new error bounds away from equality, including an improved version of Pinsker's inequality.

  4. Entropy and temperatures of Nariai black hole

    NASA Astrophysics Data System (ADS)

    Eune, Myungseok; Kim, Wontae

    2013-06-01

    The statistical entropy of the Nariai black hole in a thermal equilibrium is calculated by using the brick-wall method. Even if the temperature depends on the choice of the timelike Killing vector, the entropy can be written by the ordinary area law which agrees with the Wald entropy. We discuss some physical consequences of this result and the properties of the temperatures.

  5. Entropy of local smeared field observables

    NASA Astrophysics Data System (ADS)

    Satz, Alejandro

    2017-01-01

    We re-conceptualize the usual entanglement entropy of quantum fields in a spatial region as a limiting case of a more general and well-defined quantity, the entropy of a subalgebra of smeared field observables. We introduce this notion, discuss various examples, and recover from it the area law for the entanglement entropy of a sphere in Minkowski space.

  6. Tachyon condensation and black hole entropy.

    PubMed

    Dabholkar, Atish

    2002-03-04

    String propagation on a cone with deficit angle 2pi(1-1 / N) is considered for the purpose of computing the entropy of a large mass black hole. The entropy computed using the recent results on condensation of twisted-sector tachyons in this theory is found to be in precise agreement with the Bekenstein-Hawking entropy.

  7. Holographic entropy and Calabi's diastasis

    NASA Astrophysics Data System (ADS)

    D'Hoker, Eric; Gutperle, Michael

    2014-10-01

    The entanglement entropy for interfaces and junctions of two-dimensional CFTs is evaluated on holographically dual half-BPS solutions to six-dimensional Type 4b supergravity with m anti-symmetric tensor supermultiplets. It is shown that the moduli space for an N-junction solution projects to N points in the Kähler manifold SO(2 , m) / (SO(2) × SO( m)). For N =2 the interface entropy is expressed in terms of the central charge and Calabi's diastasis function on SO(2 , m) / (SO(2) × SO( m)), thereby lending support from holography to a proposal of Bachas, Brunner, Douglas, and Rastelli. For N =3, the entanglement entropy for a 3-junction decomposes into a sum of diastasis functions between pairs, weighed by combinations of the three central charges, provided the flux charges are all parallel to one another or, more generally, provided the space of flux charges is orthogonal to the space of unattracted scalars. Under similar assumptions for N ≥4, the entanglement entropy for the N -junction solves a variational problem whose data consist of the N central charges, and the diastasis function evaluated between pairs of N asymptotic AdS 3 × S 3 regions.

  8. Entanglement entropy and anomaly inflow

    NASA Astrophysics Data System (ADS)

    Hughes, Taylor L.; Leigh, Robert G.; Parrikar, Onkar; Ramamurthy, Srinidhi T.

    2016-03-01

    We study entanglement entropy for parity-violating (time-reversal breaking) quantum field theories on R1 ,2 in the presence of a domain wall between two distinct parity-odd phases. The domain wall hosts a 1 +1 -dimensional conformal field theory (CFT) with nontrivial chiral central charge. Such a CFT possesses gravitational anomalies. It has been shown recently that, as a consequence, its intrinsic entanglement entropy is sensitive to Lorentz boosts around the entangling surface. Here, we show using various methods that the entanglement entropy of the three-dimensional bulk theory is also sensitive to such boosts owing to parity-violating effects, and that the bulk response to a Lorentz boost precisely cancels the contribution coming from the domain wall CFT. We argue that this can naturally be interpreted as entanglement inflow (i.e., inflow of entanglement entropy analogous to the familiar Callan-Harvey effect) between the bulk and the domain-wall, mediated by the low-lying states in the entanglement spectrum. These results can be generally applied to 2 +1 -d topological phases of matter that have edge theories with gravitational anomalies, and provide a precise connection between the gravitational anomaly of the physical edge theory and the low-lying spectrum of the entanglement Hamiltonian.

  9. Origin of the 'Extra Entropy'

    NASA Technical Reports Server (NTRS)

    Mushotzky, R.

    2008-01-01

    I will discuss how one can determine the origin of the 'extra entropy' in groups and clusters and the feedback needed in models of galaxy formation. I will stress the use of x-ray spectroscopy and imaging and the critical value that Con-X has in this regard.

  10. Numerical Calculation of Granular Entropy

    NASA Astrophysics Data System (ADS)

    Asenjo, Daniel; Paillusson, Fabien; Frenkel, Daan

    2014-03-01

    We present numerical simulations that allow us to compute the number of ways in which N particles can pack into a given volume V. Our technique modifies the method of Xu, Frenkel, and Liu [Phys. Rev. Lett. 106, 245502 (2011)] and outperforms existing direct enumeration methods by more than 200 orders of magnitude. We use our approach to study the system size dependence of the number of distinct packings of a system of up to 128 polydisperse soft disks. We show that, even though granular particles are distinguishable, we have to include a factor 1/N! to ensure that the entropy does not change when exchanging particles between systems in the same macroscopic state. Our simulations provide strong evidence that the packing entropy, when properly defined, is extensive. As different packings are created with unequal probabilities, it is natural to express the packing entropy as S=-∑ipilnpi-lnN!, where pi denotes the probability to generate the ith packing. We can compute this quantity reliably and it is also extensive. The granular entropy thus (re)defined, while distinct from the one proposed by Edwards [J. Phys. Condens. Matter 2, SA63 (1990)], does have all the properties Edwards assumed.

  11. Coherent Informational Energy and Entropy.

    ERIC Educational Resources Information Center

    Avramescu, Aurel

    1980-01-01

    Seeks to provide a common theoretical foundation for all known bibliometric laws by assimilating a systemic view of the information transfer process with a thermodynamic process, i.e., the conduction of heat in solids. The resulting diffusion model establishes new definitions for informational energy and entropy consistent with corresponding…

  12. Coherent Informational Energy and Entropy.

    ERIC Educational Resources Information Center

    Avramescu, Aurel

    1980-01-01

    Seeks to provide a common theoretical foundation for all known bibliometric laws by assimilating a systemic view of the information transfer process with a thermodynamic process, i.e., the conduction of heat in solids. The resulting diffusion model establishes new definitions for informational energy and entropy consistent with corresponding…

  13. Numerical calculation of granular entropy.

    PubMed

    Asenjo, Daniel; Paillusson, Fabien; Frenkel, Daan

    2014-03-07

    We present numerical simulations that allow us to compute the number of ways in which N particles can pack into a given volume V. Our technique modifies the method of Xu, Frenkel, and Liu [Phys. Rev. Lett. 106, 245502 (2011)] and outperforms existing direct enumeration methods by more than 200 orders of magnitude. We use our approach to study the system size dependence of the number of distinct packings of a system of up to 128 polydisperse soft disks. We show that, even though granular particles are distinguishable, we have to include a factor 1=N! to ensure that the entropy does not change when exchanging particles between systems in the same macroscopic state. Our simulations provide strong evidence that the packing entropy, when properly defined, is extensive. As different packings are created with unequal probabilities, it is natural to express the packing entropy as S = − Σ(i)p(i) ln pi − lnN!, where pi denotes the probability to generate the ith packing. We can compute this quantity reliably and it is also extensive. The granular entropy thus (re)defined, while distinct from the one proposed by Edwards [J. Phys. Condens. Matter 2, SA63 (1990)], does have all the properties Edwards assumed.

  14. Maximum entropy beam diagnostic tomography

    SciTech Connect

    Mottershead, C.T.

    1985-01-01

    This paper reviews the formalism of maximum entropy beam diagnostic tomography as applied to the Fusion Materials Irradiation Test (FMIT) prototype accelerator. The same formalism has also been used with streak camera data to produce an ultrahigh speed movie of the beam profile of the Experimental Test Accelerator (ETA) at Livermore. 11 refs., 4 figs.

  15. Entropy in an expanding universe

    NASA Astrophysics Data System (ADS)

    Frautschi, S.

    1982-08-01

    The evolution of organized structures from initial chaos in the expanding universe is demonstrated to be reconcilable with the second law of thermodynamics, and the effects of expansion and gravity on this problem are emphasized. Numerical estimates of the major sources of entropy increase are calculated, including the entropy increase in stars, the earth, black hole formation and decay, quantum tunneling of matter into black holes, positronium formation and decay, etc. An expanding 'causal' region is defined in which the entropy, though increasing, tends to fall further and further behind its maximum possible value, thus allowing for the development of order. That is, the classical heat death argument does not hold, because an expanding universe never achieves equilibrium and never reaches a constant temperature. Also considered are questions of whether entropy will continue increasing without limit in the future, and whether such increase in the form of Hawking radiation or radiation from positronium might enable life to maintain itself permanently. Attempts to find a scheme for preserving life based on solid structures fail because events such as quantum tunneling recurrently disorganize matter on a very long but fixed time scale.

  16. Entropy, semantic relatedness and proximity.

    PubMed

    Hahn, Lance W; Sivley, Robert M

    2011-09-01

    Although word co-occurrences within a document have been demonstrated to be semantically useful, word interactions over a local range have been largely neglected by psychologists due to practical challenges. Shannon's (Bell Systems Technical Journal, 27, 379-423, 623-665, 1948) conceptualization of information theory suggests that these interactions should be useful for understanding communication. Computational advances make an examination of local word-word interactions possible for a large text corpus. We used Brants and Franz's (2006) dataset to generate conditional probabilities for 62,474 word pairs and entropy calculations for 9,917 words in Nelson, McEvoy, and Schreiber's (Behavior Research Methods, Instruments, & Computers, 36, 402-407, 2004) free association norms. Semantic associativity correlated moderately with the probabilities and was stronger when the two words were not adjacent. The number of semantic associates for a word and the entropy of a word were also correlated. Finally, language entropy decreases from 11 bits for single words to 6 bits per word for four-word sequences. The probabilities and entropies discussed here are included in the supplemental materials for the article.

  17. Entropy of dynamical social networks

    NASA Astrophysics Data System (ADS)

    Zhao, Kun; Karsai, Marton; Bianconi, Ginestra

    2012-02-01

    Dynamical social networks are evolving rapidly and are highly adaptive. Characterizing the information encoded in social networks is essential to gain insight into the structure, evolution, adaptability and dynamics. Recently entropy measures have been used to quantify the information in email correspondence, static networks and mobility patterns. Nevertheless, we still lack methods to quantify the information encoded in time-varying dynamical social networks. In this talk we present a model to quantify the entropy of dynamical social networks and use this model to analyze the data of phone-call communication. We show evidence that the entropy of the phone-call interaction network changes according to circadian rhythms. Moreover we show that social networks are extremely adaptive and are modified by the use of technologies such as mobile phone communication. Indeed the statistics of duration of phone-call is described by a Weibull distribution and is significantly different from the distribution of duration of face-to-face interactions in a conference. Finally we investigate how much the entropy of dynamical social networks changes in realistic models of phone-call or face-to face interactions characterizing in this way different type human social behavior.

  18. Entropy and plasma sheet transport

    NASA Astrophysics Data System (ADS)

    Wolf, R. A.; Wan, Yifei; Xing, X.; Zhang, J.-C.; Sazykin, S.

    2009-09-01

    This paper presents a focused review of the role of entropy in plasma sheet transport and also describes new calculations of the implications of plasma sheet entropy conservation for the case where the plasma pressure is not isotropic. For the isotropic case, the entropy varies in proportion to log[PV5/3], where P is plasma pressure and V is the volume of a tube containing one unit of magnetic flux. Theory indicates that entropy should be conserved in the ideal MHD approximation, and a generalized form of entropy conservation also holds when transport by gradient/curvature drift is included. These considerations lead to the conclusion that under the assumption of strong, elastic pitch angle scattering, PV5/3 should be approximately conserved over large regions of the plasma sheet, though gradient/curvature drift causes major violations in the innermost region. Statistical magnetic field and plasma models lead to the conclusion that PV5/3 increases significantly with distance downtail (pressure balance inconsistency). We investigate the possibility that the inconsistency could be removed or reduced by eliminating the assumption of strong, elastic pitch angle scattering but find that the inconsistency becomes worse if the first two adiabatic invariants are conserved as the particles drift. We consider two previously suggested mechanisms, bubbles and gradient/curvature drift, and conclude that the combination of the two is likely adequate for resolving the pressure balance inconsistency. Quantitatively accurate estimation of the efficiency of these mechanisms depends on finding a method of estimating PV5/3 (or equivalent) from spacecraft measurements. Two present approaches to that problem are discussed.

  19. Stokes-Einstein relation and excess entropy in Al-rich Al-Cu melts

    NASA Astrophysics Data System (ADS)

    Pasturel, A.; Jakse, N.

    2016-07-01

    We investigate the conditions for the validity of the Stokes-Einstein relation that connects diffusivity to viscosity in melts using entropy-scaling relationships developed by Rosenfeld. Employing ab initio molecular dynamics simulations to determine transport and structural properties of liquid Al1-xCux alloys (with composition x ≤ 0.4), we first show that reduced self-diffusion coefficients and viscosities, according to Rosenfeld's formulation, scale with the two-body approximation of the excess entropy except the reduced viscosity for x = 0.4. Then, we use our findings to evidence that the Stokes-Einstein relation using effective atomic radii is not valid in these alloys while its validity can be related to the temperature dependence of the partial pair-excess entropies of both components. Finally, we derive a relation between the ratio of the self-diffusivities of the components and the ratio of their pair excess entropies.

  20. Entropy-power uncertainty relations: towards a tight inequality for all Gaussian pure states

    NASA Astrophysics Data System (ADS)

    Hertz, Anaelle; Jabbour, Michael G.; Cerf, Nicolas J.

    2017-09-01

    We show that a proper expression of the uncertainty relation for a pair of canonically-conjugate continuous variables relies on entropy power, a standard notion in Shannon information theory for real-valued signals. The resulting entropy-power uncertainty relation is equivalent to the entropic formulation of the uncertainty relation due to Bialynicki-Birula and Mycielski, but can be further extended to rotated variables. Hence, based on a reasonable assumption, we give a partial proof of a tighter form of the entropy-power uncertainty relation taking correlations into account and provide extensive numerical evidence of its validity. Interestingly, it implies the generalized (rotation-invariant) Schrödinger-Robertson uncertainty relation exactly as the original entropy-power uncertainty relation implies Heisenberg relation. It is saturated for all Gaussian pure states, in contrast with hitherto known entropic formulations of the uncertainty principle.

  1. Uncertainty assessment of Si molar mass measurements

    NASA Astrophysics Data System (ADS)

    Mana, G.; Massa, E.; Valkiers, S.; Willenberg, G.-D.

    2010-01-01

    The uncertainty of the Si molar mass measurement is theoretically investigated by means of a two-isotope model, with particular emphasis to the role of this measurement in the determination of the Avogadro constant. This model allows an explicit calibration formula to be given and propagation of error analysis to be made. It also shows that calibration cannot correct for non-linearity.

  2. Natal maxillary primary molars: case report.

    PubMed

    Galassi, Marlei Seccani; Santos-Pinto, Lourdes; Ramalho, Lizete Toledo Oliveira

    2004-01-01

    An unusual case of a newborn with two immature natal maxillary molars is presented. Clinical and histological examination showed that the teeth were rootless and incompletely mineralized. The patient was followed up during one year and we confirmed that the natal teeth were from normal primary series.

  3. Mass versus molar doses, similarities and differences.

    PubMed

    Chmielewska, A; Lamparczyk, H

    2008-11-01

    Generally, they are two systems expressing the amounts of active substance in a given drug product, i.e. mass and molar dose. Currently, the dose system based on the mass is widely used in which doses are expressed in grams or milligrams. On the other hand, the molar dose system is in direct relation to the number of molecules. Hence, the objective of this work was to compare both systems in order to find their advantages and disadvantages. Active substances belonging to the groups of antibiotics, nootropic agents, beta-blockers, vitamins, GABA-analog, COX-2 inhibitors, calcium channel antagonists, benzodiazepine receptor agonists, lipid-modifying agents (fibrates), non-steroidal anti-inflammatory drugs (profens), estrogens, neuroleptics, analgesics and benzodiazepines were considered. Moreover, products containing two active substances were also taken into account. These are mixtures of hydrochlorothiazide with active substances influencing the renin-angiotensin system and combined oral contraceptives. For each active substance, belonging to the groups mentioned above molar doses were calculated from mass doses and molar mass. Hence, groups of drugs with a single active substance, drugs with similar pharmacological activities, pharmaceutical alternatives, and drugs with a single active ingredient manufactured in different doses were compared in order to find which dose system describes more adequately differences between and within the groups mentioned above. Comparisons were supported by a number of equations, which theoretically justify the data, and relationships derived from calculations.

  4. Controlling the Shannon Entropy of Quantum Systems

    PubMed Central

    Xing, Yifan; Wu, Jun

    2013-01-01

    This paper proposes a new quantum control method which controls the Shannon entropy of quantum systems. For both discrete and continuous entropies, controller design methods are proposed based on probability density function control, which can drive the quantum state to any target state. To drive the entropy to any target at any prespecified time, another discretization method is proposed for the discrete entropy case, and the conditions under which the entropy can be increased or decreased are discussed. Simulations are done on both two- and three-dimensional quantum systems, where division and prediction are used to achieve more accurate tracking. PMID:23818819

  5. q-entropy for symbolic dynamical systems

    NASA Astrophysics Data System (ADS)

    Zhao, Yun; Pesin, Yakov

    2015-12-01

    For symbolic dynamical systems we use the Carathéodory construction as described in (Pesin 1997 Dimension Theory in Dynamical Systems, ConTemporary Views and Applications (Chicago: University of Chicago Press)) to introduce the notions of q-topological and q-metric entropies. We describe some basic properties of these entropies and in particular, discuss relations between q-metric entropy and local metric entropy. Both q-topological and q-metric entropies are new invariants respectively under homeomorphisms and metric isomorphisms of dynamical systems.

  6. Time evolution of entropy in gravitational collapse

    SciTech Connect

    Greenwood, Eric

    2009-06-01

    We study the time evolution of the entropy of a collapsing spherical domain wall, from the point of view of an asymptotic observer, by investigating the entropy of the entire system (i.e. domain wall and radiation) and induced radiation alone during the collapse. By taking the difference, we find the entropy of the collapsing domain wall, since this is the object which will form a black hole. We find that for large values of time (times larger than t/R{sub s} ≈ 8), the entropy of the collapsing domain wall is a constant, which is of the same order as the Bekenstein-Hawking entropy.

  7. Generalized gravitational entropy from total derivative action

    NASA Astrophysics Data System (ADS)

    Dong, Xi; Miao, Rong-Xin

    2015-12-01

    We investigate the generalized gravitational entropy from total derivative terms in the gravitational action. Following the method of Lewkowycz and Maldacena, we find that the generalized gravitational entropy from total derivatives vanishes. We compare our results with the work of Astaneh, Patrushev, and Solodukhin. We find that if total derivatives produced nonzero entropy, the holographic and the field-theoretic universal terms of entanglement entropy would not match. Furthermore, the second law of thermodynamics could be violated if the entropy of total derivatives did not vanish.

  8. Negative temperatures and the definition of entropy

    NASA Astrophysics Data System (ADS)

    Swendsen, Robert H.; Wang, Jian-Sheng

    2016-07-01

    The concept of negative temperature has recently received renewed interest in the context of debates about the correct definition of the thermodynamic entropy in statistical mechanics. Several researchers have identified the thermodynamic entropy exclusively with the ;volume entropy; suggested by Gibbs, and have further concluded that by this definition, negative temperatures violate the principles of thermodynamics. We disagree with these conclusions. We demonstrate that volume entropy is inconsistent with the postulates of thermodynamics for systems with non-monotonic energy densities, while a definition of entropy based on the probability distributions of macroscopic variables does satisfy the postulates of thermodynamics. Our results confirm that negative temperature is a valid extension of thermodynamics.

  9. Entropy-based portfolio models: Practical issues

    NASA Astrophysics Data System (ADS)

    Shirazi, Yasaman Izadparast; Sabiruzzaman, Md.; Hamzah, Nor Aishah

    2015-10-01

    Entropy is a nonparametric alternative of variance and has been used as a measure of risk in portfolio analysis. In this paper, the computation of entropy risk for a given set of data is discussed with illustration. A comparison between entropy-based portfolio models is made. We propose a natural extension of the mean entropy portfolio to make it more general and diversified. In terms of performance, this new model is similar to the mean-entropy portfolio when applied to real and simulated data, and offers higher return if no constraint is set for the desired return; also it is found to be the most diversified portfolio model.

  10. Controlling the shannon entropy of quantum systems.

    PubMed

    Xing, Yifan; Wu, Jun

    2013-01-01

    This paper proposes a new quantum control method which controls the Shannon entropy of quantum systems. For both discrete and continuous entropies, controller design methods are proposed based on probability density function control, which can drive the quantum state to any target state. To drive the entropy to any target at any prespecified time, another discretization method is proposed for the discrete entropy case, and the conditions under which the entropy can be increased or decreased are discussed. Simulations are done on both two- and three-dimensional quantum systems, where division and prediction are used to achieve more accurate tracking.

  11. Tsallis Entropy Composition and the Heisenberg Group

    NASA Astrophysics Data System (ADS)

    Kalogeropoulos, Nikos

    2013-03-01

    We present an embedding of the Tsallis entropy into the three-dimensional Heisenberg group, in order to understand the meaning of generalized independence as encoded in the Tsallis entropy composition property. We infer that the Tsallis entropy composition induces fractal properties on the underlying Euclidean space. Using a theorem of Milnor/Wolf/Tits/Gromov, we justify why the underlying configuration/phase space of systems described by the Tsallis entropy has polynomial growth for both discrete and Riemannian cases. We provide a geometric framework that elucidates Abe's formula for the Tsallis entropy, in terms the Pansu derivative of a map between sub-Riemannian spaces.

  12. Till Surgery do us Part: Unexpected Bilateral Kissing Molars.

    PubMed

    Anish, Narayanankutty; Vivek, Velayudhannair; Thomas, Sunila; Daniel, Vineet Alex; Thomas, Jincy; Ranimol, Prasanna

    2015-01-28

    The occurrence impacted teeth, single or multiple is very common. But, phenomenon of kissing molars is an extremely rare phenomenon. Mandibular third molars are the most common impacted teeth. Mandibular first or second molars does not share the same frequency of occurrence. But, there are rare cases in which the occlusal surfaces of impacted molars are united by the same follicular space and the roots point in the opposite direction, and are termed as kissing molars. Sometimes, these teeth will be associated with pathologies. This article reports a rare case of mandibular bilateral kissing molars.

  13. Root and Root Canal Morphology of Human Third Molar Teeth.

    PubMed

    Mohammadi, Zahed; Jafarzadeh, Hamid; Shalavi, Sousan; Bandi, Shilpa; Patil, Shankargouda

    2015-04-01

    Successful root canal treatment depends on having comprehensive information regarding the root(s)/canal(s) anatomy. Dentists may have some complication in treatment of third molars because the difficulty in their access, their aberrant occlusal anatomy and different patterns of eruption. The aim of this review was to review and address the number of roots and root canals in third molars, prevalence of confluent canals in third molars, C-shaped canals, dilaceration and fusion in third molars, autotransplantation of third molars and endodontic treatment strategies for third molars.

  14. Heat capacity, enthalpy and entropy of ternary bismuth tantalum oxides

    NASA Astrophysics Data System (ADS)

    Leitner, J.; Jakeš, V.; Sofer, Z.; Sedmidubský, D.; Růžička, K.; Svoboda, P.

    2011-02-01

    Heat capacity and enthalpy increments of ternary bismuth tantalum oxides Bi 4Ta 2O 11, Bi 7Ta 3O 18 and Bi 3TaO 7 were measured by the relaxation time method (2-280 K), DSC (265-353 K) and drop calorimetry (622-1322 K). Temperature dependencies of the molar heat capacity in the form Cpm =445.8+0.005451 T-7.489×10 6/ T2 J K -1 mol -1, Cpm =699.0+0.05276 T-9.956×10 6/ T2 J K -1 mol -1 and Cpm =251.6+0.06705 T-3.237×10 6/ T2 J K -1 mol -1 for Bi 3TaO 7, Bi 4Ta 2O 11 and for Bi 7Ta 3O 18, respectively, were derived by the least-squares method from the experimental data. The molar entropies at 298.15 K, S° m(298.15 K)=449.6±2.3 J K -1 mol -1 for Bi 4Ta 2O 11, S° m(298.15 K)=743.0±3.8 J K -1 mol -1 for Bi 7Ta 3O 18 and S° m(298.15 K)=304.3±1.6 J K -1 mol -1 for Bi 3TaO 7, were evaluated from the low-temperature heat capacity measurements.

  15. Incidence of distal caries in mandibular second molars due to impacted third molars: Nonintervention strategy of asymptomatic third molars causes harm? A retrospective study.

    PubMed

    Srivastava, Nikhil; Shetty, Akshay; Goswami, Rahul Dev; Apparaju, Vijay; Bagga, Vivek; Kale, Saurabh

    2017-01-01

    Removal of impacted third molars is the most common oral surgical procedure. Many investigators have questioned the necessity of removal in patients who are free of symptoms or associated pathologies. The aim of this retrospective study was to evaluate the incidence of caries on distal aspect of mandibular second molars in patients referred for corresponding third molar assessment and to identify its association with angular position and depth of the impacted mandibular third molars based on the classification of Pell and Gregory. Records of 150 patients with impacted third molar presenting to the Department of Oral and Maxillofacial Surgery, Sri Rajiv Gandhi College of Dental Sciences and Hospital, were assessed retrospectively. The radiographic angulation and depth of mandibular third molar impaction were determined and compared to determine the relationship with incidence of caries on the distal surface of the second molar. According to this study results, 37.5% cases show caries on the distal aspect of mandibular second molars. The incidence of caries with mesioangular impacted third molars was 55%. A majority of these mesioangular cases were Level B and Class I as per the Pell and Gregory classification. The prophylactic extraction of mandibular third molars is indicated if the angulation is between 30° and 70° and is justified by incidence of distal caries in the second molars.

  16. Incidence of distal caries in mandibular second molars due to impacted third molars: Nonintervention strategy of asymptomatic third molars causes harm? A retrospective study

    PubMed Central

    Srivastava, Nikhil; Shetty, Akshay; Goswami, Rahul Dev; Apparaju, Vijay; Bagga, Vivek; Kale, Saurabh

    2017-01-01

    Background: Removal of impacted third molars is the most common oral surgical procedure. Many investigators have questioned the necessity of removal in patients who are free of symptoms or associated pathologies. Aim: The aim of this retrospective study was to evaluate the incidence of caries on distal aspect of mandibular second molars in patients referred for corresponding third molar assessment and to identify its association with angular position and depth of the impacted mandibular third molars based on the classification of Pell and Gregory. Methodology: Records of 150 patients with impacted third molar presenting to the Department of Oral and Maxillofacial Surgery, Sri Rajiv Gandhi College of Dental Sciences and Hospital, were assessed retrospectively. The radiographic angulation and depth of mandibular third molar impaction were determined and compared to determine the relationship with incidence of caries on the distal surface of the second molar. Results: According to this study results, 37.5% cases show caries on the distal aspect of mandibular second molars. The incidence of caries with mesioangular impacted third molars was 55%. A majority of these mesioangular cases were Level B and Class I as per the Pell and Gregory classification. Conclusion: The prophylactic extraction of mandibular third molars is indicated if the angulation is between 30° and 70° and is justified by incidence of distal caries in the second molars. PMID:28251102

  17. Entropy-Based Financial Asset Pricing

    PubMed Central

    Ormos, Mihály; Zibriczky, Dávid

    2014-01-01

    We investigate entropy as a financial risk measure. Entropy explains the equity premium of securities and portfolios in a simpler way and, at the same time, with higher explanatory power than the beta parameter of the capital asset pricing model. For asset pricing we define the continuous entropy as an alternative measure of risk. Our results show that entropy decreases in the function of the number of securities involved in a portfolio in a similar way to the standard deviation, and that efficient portfolios are situated on a hyperbola in the expected return – entropy system. For empirical investigation we use daily returns of 150 randomly selected securities for a period of 27 years. Our regression results show that entropy has a higher explanatory power for the expected return than the capital asset pricing model beta. Furthermore we show the time varying behavior of the beta along with entropy. PMID:25545668

  18. Entropy Generation Across Earth's Bow Shock

    NASA Technical Reports Server (NTRS)

    Parks, George K.; McCarthy, Michael; Fu, Suiyan; Lee E. s; Cao, Jinbin; Goldstein, Melvyn L.; Canu, Patrick; Dandouras, Iannis S.; Reme, Henri; Fazakerley, Andrew; Lin, Naiguo; Wilber, Mark

    2011-01-01

    Earth's bow shock is a transition layer that causes an irreversible change in the state of plasma that is stationary in time. Theories predict entropy increases across the bow shock but entropy has never been directly measured. Cluster and Double Star plasma experiments measure 3D plasma distributions upstream and downstream of the bow shock that allow calculation of Boltzmann's entropy function H and his famous H-theorem, dH/dt O. We present the first direct measurements of entropy density changes across Earth's bow shock. We will show that this entropy generation may be part of the processes that produce the non-thermal plasma distributions is consistent with a kinetic entropy flux model derived from the collisionless Boltzmann equation, giving strong support that solar wind's total entropy across the bow shock remains unchanged. As far as we know, our results are not explained by any existing shock models and should be of interests to theorists.

  19. Entropy-based financial asset pricing.

    PubMed

    Ormos, Mihály; Zibriczky, Dávid

    2014-01-01

    We investigate entropy as a financial risk measure. Entropy explains the equity premium of securities and portfolios in a simpler way and, at the same time, with higher explanatory power than the beta parameter of the capital asset pricing model. For asset pricing we define the continuous entropy as an alternative measure of risk. Our results show that entropy decreases in the function of the number of securities involved in a portfolio in a similar way to the standard deviation, and that efficient portfolios are situated on a hyperbola in the expected return-entropy system. For empirical investigation we use daily returns of 150 randomly selected securities for a period of 27 years. Our regression results show that entropy has a higher explanatory power for the expected return than the capital asset pricing model beta. Furthermore we show the time varying behavior of the beta along with entropy.

  20. Nonparametric entropy estimation using kernel densities.

    PubMed

    Lake, Douglas E

    2009-01-01

    The entropy of experimental data from the biological and medical sciences provides additional information over summary statistics. Calculating entropy involves estimates of probability density functions, which can be effectively accomplished using kernel density methods. Kernel density estimation has been widely studied and a univariate implementation is readily available in MATLAB. The traditional definition of Shannon entropy is part of a larger family of statistics, called Renyi entropy, which are useful in applications that require a measure of the Gaussianity of data. Of particular note is the quadratic entropy which is related to the Friedman-Tukey (FT) index, a widely used measure in the statistical community. One application where quadratic entropy is very useful is the detection of abnormal cardiac rhythms, such as atrial fibrillation (AF). Asymptotic and exact small-sample results for optimal bandwidth and kernel selection to estimate the FT index are presented and lead to improved methods for entropy estimation.

  1. Evaluation of two flap designs on the mandibular second molar after third molar extractions

    PubMed Central

    Alqahtani, Nabeeh A; Khaleelahmed, S; Desai, Farheen

    2017-01-01

    Background: The extraction of third molars is associated with some clinical outcomes and periodontal problems. It is imperative to note that the type of incision used in the surgery for the removal of the impacted third molar is critical. The design of the flap influences the healing of the surgically created defect and damage to the distal periodontal area of the adjacent second molar. However, till date, there have been conflicting reports on the influence of different flap designs used for the surgical removal of impacted third molars. Aim: The present study aimed to comparatively evaluate the clinical outcomes and periodontal status of the adjacent second molar, when two different flap designs, namely, the envelope and the modified triangular flap designs were used. Materials and Methods: Sixty female patients with bilateral impacted third molars completed the study with envelope flap on one side and modified triangular flap design on the other side of the mandible for third molar removal. Clinical parameters including pain, dehiscence and swelling were assessed postoperatively and periodontal probing depth (PPD) on the distal aspect of adjacent second molar were assessed both pre- and post-operatively. Results: The results were assessed on 1, 3 and 8 days for pain using visual analog scale. The subjective perception of swelling was evaluated on 3, 7 and 15 days postoperatively in a similar manner. The results of the periodontal parameters were evaluated both preoperatively and 3 months postoperatively, with cautious exploration using a University of North Carolina (UNC)-15 periodontal probe. The statistically significant results for swelling and PPD were noted for the two flap groups using the Chi-square test (P < 0.05). Conclusion: The study revealed that the modified triangular flap had lesser postoperative PPDs and dehiscence. The envelope flap was better when swelling was analyzed. The pain scores, though slightly higher for the modified triangular flap

  2. The incidence of periodontal defects distal to the maxillary second molar after impacted third molar extraction.

    PubMed

    Coleman, Michael; McCormick, Adam; Laskin, Daniel M

    2011-02-01

    This study assessed the incidence of periodontal defects on the distal aspect of maxillary second molars after extraction of impacted maxillary third molars. Subjects enrolled in this institutional review board-approved prospective study consisted of healthy young patients having extraction of at least 1 asymptomatic impacted maxillary third molar adjacent to a second molar. Preoperative periodontal probing data were collected from 4 sites (midbuccal, distobuccal, midpalatal, and distopalatal) on each adjacent second molar, and a similar probing examination was performed at a mean of 6 months postoperatively. All subjects were treated under general anesthesia or conscious sedation by upper-level residents in the outpatient clinic. Twenty subjects with a total of 38 impacted maxillary third molars were treated. There were 9 male subjects (45%) and 11 female subjects (55%), with a mean age of 17 years (range, 14-22 years). The mean follow-up interval was 6 months, with a range of 3 to 15 months. Of the 152 probing sites measured, 92 (61%) decreased, 56 (37%) remained unchanged, and only 4 (2.6%) increased. A decrease in probing depth of 1 mm was found in 35 (23%) of the sites, a decrease of 2 mm was seen in 32 (21%), and 25 (16%) decreased by 3 mm or more. Of the 152 sites probed, 4 (2.6%) increased by 1 or 2 mm. Extraction of the impacted maxillary third molar does not result in significant periodontal defects on the distal aspect of the adjacent second molar, and in many cases it results in an improvement of the probing depths on these teeth. Copyright © 2011 American Association of Oral and Maxillofacial Surgeons. Published by Elsevier Inc. All rights reserved.

  3. Assessment of association between molar incisor hypomineralization and hypomineralized second primary molar

    PubMed Central

    Mittal, Rakesh; Chandak, Shweta; Chandwani, Manisha; Singh, Prabhat; Pimpale, Jitesh

    2016-01-01

    Background: The term molar incisor hypomineralization (MIH) has been described as a clinical entity of systemic origin affecting the enamel of one or all first permanent molars and also the incisors; less frequently the second primary molars have also been reported to develop hypomineralization of the enamel, along with MIH. Aim: To scrutinize the association between hypomineralized second primary molars (HSPMs) and MIH and their prevalence in schoolgoing pupils in Nagpur, Maharashtra, India and the associated severity of dental caries. Design: A sample of 1,109 pupils belonging to 3–12-year-old age group was included. The entire sample was then divided into Group I (3–5 years) and Group II (6–12 years). The scoring criteria proposed by the European Academy of Pediatric Dentistry for hypomineralization was used to score HSPM and MIH. The International Caries Detection and Assessment System II (ICDAS II) was used for appraising caries status in the hypomineralized molars. The examination was conducted by a single calibrated dentist in schools in daylight. The results, thus obtained, were statistically analyzed using Chi-square test and odds ratio. Result: Of the children examined, 10 in Group I (4.88%) had HSPM and 63 in Group II (7.11%) had MIH in at least one molar. In Group II, out of 63 subjects diagnosed with MIH, 30 subjects (48%) also had HSPM. Carious lesions with high severity were appreciated in hypomineralized molars. Conclusion: The prevalence of HSPM was 4.88% and of MIH was 7.11%. Approximately half of the affected first permanent molars were associated with HSPM. The likelihood of development of caries increased with the severity of hypomineralization defect. PMID:27011930

  4. Entropy and climate. I - ERBE observations of the entropy production of the earth

    NASA Technical Reports Server (NTRS)

    Stephens, G. L.; O'Brien, D. M.

    1993-01-01

    An approximate method for estimating the global distributions of the entropy fluxes flowing through the upper boundary of the climate system is introduced, and an estimate of the entropy exchange between the earth and space and the entropy production of the planet is provided. Entropy fluxes calculated from the Earth Radiation Budget Experiment measurements show how the long-wave entropy flux densities dominate the total entropy fluxes at all latitudes compared with the entropy flux densities associated with reflected sunlight, although the short-wave flux densities are important in the context of clear sky-cloudy sky net entropy flux differences. It is suggested that the entropy production of the planet is both constant for the 36 months of data considered and very near its maximum possible value. The mean value of this production is 0.68 x 10 exp 15 W/K, and the amplitude of the annual cycle is approximately 1 to 2 percent of this value.

  5. Characterization of third molar morphometric variables.

    PubMed

    Trinks, Pablo W; Grifo, María Belén; Pari, Fernando; Amer, Mariano Ar; Sánchez, Gabriel A

    2016-09-01

    The third molar is a tooth of anatomical, surgical, prosthetic and forensic dental interest. However, there is currently a lack of updated data regarding its morphology. The aim of this study was to determine the morphometric features of third molars and their predictive capability as regards dental arch and side. Two calibrated operators (ƙ = 0.83) determined the cervicalocclusalvestibular (COV), cervicalocclusalpalatal (COP) and occlusalapical (OA) distances, mesiodistal (MD), and vestibularpalatal (VP) diameters, number of roots (R) and number of cusps (C) of 961 cadaveric third molars, both upper (n = 462) and lower (n = 499), using a CONCOR 050 thin mandible caliper (resolution 0.01 mm). Median and range for each variable were calculated and compared using Mann Whitney nonparametric test (p < 0.05). Multivariate cluster analysis was used to determine the predictive capability of each variable for dental arch and side. For upper molars (UM), 50.6% were from the right side (RS) and 49.4% from the left side (LS), while for lower molars (LM), 60.9% were from the RS and 39.1% from the LS. No significant difference was found in the study variables in LM according to side. For UM, MD diameter (10.90 mm), COP(7.42 mm) distance and number of R (3) were significantly higher (p < 0.05) forRS, and number of C (3) was higher (p < 0.0001) for LS. They were also significant predictive grouping factors for side. For dental arch, OA (17.84 mm) and COV (7.60 mm) distances, MD (11.26 mm) diameter and the number of C (5) were significantly higher (p < 0.0001) for LM, while VP (10.84 mm) and COP (7.34 mm) distances, and the number of R (3) were significantly higher (p < 0.0001) for UM. These variables were significant predictive factors for dental arch. Despite the morphometric heterogeneity of third molars, there are intrinsic parameters with predictive capability for dental arch and side, but it would be advisable to supplement this study with data from topographic occlusal

  6. Entanglement entropy in jammed CFTs

    NASA Astrophysics Data System (ADS)

    Mefford, Eric

    2017-09-01

    We construct solutions to the Einstein equations for asymptotically locally Anti-de Sitter spacetimes with four, five, and six dimensional Reissner-Nordström boundary metrics. These spacetimes are gravitational duals to "jammed" CFTs on those backgrounds at infinite N and strong coupling. For these spacetimes, we calculate the boundary stress tensor as well as compute entanglement entropies for ball shaped regions as functions of the boundary black hole temperature T BH. From this, we see how the CFT prevents heat flow from the black hole to the vacuum at spatial infinity. We also compute entanglement entropies for a three dimensional boundary black hole using the AdS C-metric. We compare our results to previous work done in similar spacetimes.

  7. Preserved entropy and fragile magnetism

    SciTech Connect

    Canfield, Paul C.; Bud’ko, Sergey L.

    2016-07-05

    Here, a large swath of quantum critical and strongly correlated electron systems can be associated with the phenomena of preserved entropy and fragile magnetism. In this overview we present our thoughts and plans for the discovery and development of lanthanide and transition metal based, strongly correlated systems that are revealed by suppressed, fragile magnetism, quantum criticality, or grow out of preserved entropy. We will present and discuss current examples such as YbBiPt, YbAgGe, YbFe2Zn20, PrAg2In, BaFe2As2, CaFe2As2, LaCrSb3 and LaCrGe3 as part of our motivation and to provide illustrative examples.

  8. Preserved entropy and fragile magnetism

    DOE PAGES

    Canfield, Paul C.; Bud’ko, Sergey L.

    2016-07-05

    Here, a large swath of quantum critical and strongly correlated electron systems can be associated with the phenomena of preserved entropy and fragile magnetism. In this overview we present our thoughts and plans for the discovery and development of lanthanide and transition metal based, strongly correlated systems that are revealed by suppressed, fragile magnetism, quantum criticality, or grow out of preserved entropy. We will present and discuss current examples such as YbBiPt, YbAgGe, YbFe2Zn20, PrAg2In, BaFe2As2, CaFe2As2, LaCrSb3 and LaCrGe3 as part of our motivation and to provide illustrative examples.

  9. Preserved entropy and fragile magnetism.

    PubMed

    Canfield, Paul C; Bud'ko, Sergey L

    2016-08-01

    A large swath of quantum critical and strongly correlated electron systems can be associated with the phenomena of preserved entropy and fragile magnetism. In this overview we present our thoughts and plans for the discovery and development of lanthanide and transition metal based, strongly correlated systems that are revealed by suppressed, fragile magnetism, quantum criticality, or grow out of preserved entropy. We will present and discuss current examples such as YbBiPt, YbAgGe, YbFe2Zn20, PrAg2In, BaFe2As2, CaFe2As2, LaCrSb3 and LaCrGe3 as part of our motivation and to provide illustrative examples.

  10. A Note on Entropy Estimation.

    PubMed

    Schürmann, Thomas

    2015-10-01

    We compare an entropy estimator H(z) recently discussed by Zhang (2012) with two estimators, H(1) and H(2), introduced by Grassberger (2003) and Schürmann (2004). We prove the identity H(z) ≡ H(1), which has not been taken into account by Zhang (2012). Then we prove that the systematic error (bias) of H(1) is less than or equal to the bias of the ordinary likelihood (or plug-in) estimator of entropy. Finally, by numerical simulation, we verify that for the most interesting regime of small sample estimation and large event spaces, the estimator H(2) has a significantly smaller statistical error than H(z).

  11. Preserved entropy and fragile magnetism

    SciTech Connect

    Canfield, Paul C.; Bud’ko, Sergey L.

    2016-07-05

    Here, a large swath of quantum critical and strongly correlated electron systems can be associated with the phenomena of preserved entropy and fragile magnetism. In this overview we present our thoughts and plans for the discovery and development of lanthanide and transition metal based, strongly correlated systems that are revealed by suppressed, fragile magnetism, quantum criticality, or grow out of preserved entropy. We will present and discuss current examples such as YbBiPt, YbAgGe, YbFe2Zn20, PrAg2In, BaFe2As2, CaFe2As2, LaCrSb3 and LaCrGe3 as part of our motivation and to provide illustrative examples.

  12. Biological adaptabilities and quantum entropies.

    PubMed

    Kirby, Kevin G

    2002-01-01

    The entropy-based theory of adaptability set forth by Michael Conrad in the early 1970s continued to appear in his work for over two decades, and was the subject of the only book he published in his lifetime. He applied this theory to a host of subjects ranging from enzyme dynamics to sociology. This paper reviews the formalism of adaptability theory, clarifying some of its mathematical and interpretive difficulties. The theory frames the computational tradeoff principle, a thesis that was the most frequently recurring claim in his work. The formulation of adaptability theory presented here allows the introduction of quantum entropy functions into the theory, revealing an interesting relationship between adaptability and another one of Conrad's deep preoccupations, the role of quantum processes in life.

  13. Entropy shaping by shock decay

    NASA Astrophysics Data System (ADS)

    Piriz, A. R.; Sun, Y. B.; Tahir, N. A.

    2016-11-01

    A previous model [Piriz et al., Phys. Plasmas 23, 032704 (2016)] developed for describing the evolution of a shock wave driven by an arbitrary pressure pulse, is shown to be suitable for calculating the entropy shaping induced by a shock of decaying intensity. It is also shown that by allowing a causal connection between the shock and the piston, the model results to be complementary to the well-known self-similar solution for the impulsive loading problem, which is valid in the asymptotic regime when both fronts become decoupled. As a consequence, the entropy distribution depends on the details of the driving pressure pulse. A comparison with the available numerical simulations is presented.

  14. Bacterial chemotaxis and entropy production

    PubMed Central

    Županović, Paško; Brumen, Milan; Jagodič, Marko; Juretić, Davor

    2010-01-01

    Entropy production is calculated for bacterial chemotaxis in the case of a migrating band of bacteria in a capillary tube. It is found that the speed of the migrating band is a decreasing function of the starting concentration of the metabolizable attractant. The experimentally found dependence of speed on the starting concentration of galactose, glucose and oxygen is fitted with power-law functions. It is found that the corresponding exponents lie within the theoretically predicted interval. The effect of the reproduction of bacteria on band speed is considered, too. The acceleration of the band is predicted due to the reproduction rate of bacteria. The relationship between chemotaxis, the maximum entropy production principle and the formation of self-organizing structure is discussed. PMID:20368258

  15. Manufacturing of High Entropy Alloys

    NASA Astrophysics Data System (ADS)

    Jablonski, Paul D.; Licavoli, Joseph J.; Gao, Michael C.; Hawk, Jeffrey A.

    2015-07-01

    High entropy alloys (HEAs) have generated interest in recent years due to their unique positioning within the alloy world. By incorporating a number of elements in high proportion they have high configurational entropy, and thus they hold the promise of interesting and useful properties such as enhanced strength and phase stability. The present study investigates the microstructure of two single-phase face-centered cubic (FCC) HEAs, CoCrFeNi and CoCrFeNiMn, with special attention given to melting, homogenization and thermo-mechanical processing. Large-scale ingots were made by vacuum induction melting to avoid the extrinsic factors inherent in small-scale laboratory button samples. A computationally based homogenization heat treatment was applied to both alloys in order to eliminate segregation due to normal ingot solidification. The alloys fabricated well, with typical thermo-mechanical processing parameters being employed.

  16. Removal of Deeply Impacted Mandibular Molars by Sagittal Split Osteotomy

    PubMed Central

    Isler, Sabri Cemil

    2016-01-01

    Mandibular third molars are the most common impacted teeth. Mandibular first and second molars do not share the same frequency of occurrence. In rare cases the occlusal surfaces of impacted molars are united by the same follicular space and the roots pointing in opposite direction; these are called kissing molars. In some cases, a supernumerary fourth molar can be seen as unerupted and, in this case, such a supernumerary, deeply impacted fourth molar is seen neighboring kissing molars. The extraction of deeply impacted wisdom molars from the mandible may necessitate excessive bone removal and it causes complications such as damage to the inferior alveolar nerve and iatrogenic fractures of the mandible. This case report describes the use of the sagittal split osteotomy technique to avoid extensive bone removal and protect the inferior alveolar nerve during surgical extruction of multiple impacted teeth. PMID:27429810

  17. Entropy estimation and Fibonacci numbers

    NASA Astrophysics Data System (ADS)

    Timofeev, Evgeniy A.; Kaltchenko, Alexei

    2013-05-01

    We introduce a new metric on a space of right-sided infinite sequences drawn from a finite alphabet. Emerging from a problem of entropy estimation of a discrete stationary ergodic process, the metric is important on its own part and exhibits some interesting properties. Notably, the number of distinct metric values for a set of sequences of length m is equal to Fm+3 - 1, where Fm is a Fibonacci number.

  18. Coverage-adjusted entropy estimation.

    PubMed

    Vu, Vincent Q; Yu, Bin; Kass, Robert E

    2007-09-20

    Data on 'neural coding' have frequently been analyzed using information-theoretic measures. These formulations involve the fundamental and generally difficult statistical problem of estimating entropy. We review briefly several methods that have been advanced to estimate entropy and highlight a method, the coverage-adjusted entropy estimator (CAE), due to Chao and Shen that appeared recently in the environmental statistics literature. This method begins with the elementary Horvitz-Thompson estimator, developed for sampling from a finite population, and adjusts for the potential new species that have not yet been observed in the sample-these become the new patterns or 'words' in a spike train that have not yet been observed. The adjustment is due to I. J. Good, and is called the Good-Turing coverage estimate. We provide a new empirical regularization derivation of the coverage-adjusted probability estimator, which shrinks the maximum likelihood estimate. We prove that the CAE is consistent and first-order optimal, with rate O(P)(1/log n), in the class of distributions with finite entropy variance and that, within the class of distributions with finite qth moment of the log-likelihood, the Good-Turing coverage estimate and the total probability of unobserved words converge at rate O(P)(1/(log n)(q)). We then provide a simulation study of the estimator with standard distributions and examples from neuronal data, where observations are dependent. The results show that, with a minor modification, the CAE performs much better than the MLE and is better than the best upper bound estimator, due to Paninski, when the number of possible words m is unknown or infinite.

  19. The entropy solution of a hyperbolic-parabolic mixed type equation.

    PubMed

    Zhan, Huashui

    2016-01-01

    The entropy solution of the equation [Formula: see text]is considered. Besides the usual initial value, only a partial boundary value is imposed. By choosing some special test functions, the stability of the solutions is obtained by Kruzkov's bi-variables method, provided that [Formula: see text] is an unit n-dimensional cube or the half space.

  20. Cross Burg entropy maximization and its application to ringing suppression in image reconstruction.

    NASA Astrophysics Data System (ADS)

    Cao, Yu; Eggermont, P. P. B.; Terebey, S.

    1999-02-01

    The authors present a multiplicative algorithm for image reconstruction, together with a partial convergence proof. The iterative scheme aims to maximize cross Burg entropy between modeled and measured data. Its application to infrared astronomical satellite (IRAS) data shows reduced ringing around point sources, compared to the EM (Richardson-Lucy) algorithm.

  1. Entropy in an expanding universe.

    PubMed

    Frautschi, S

    1982-08-13

    The question of how the observed evolution of organized structures from initial chaos in the expanding universe can be reconciled with the laws of statistical mechanics is studied, with emphasis on effects of the expansion and gravity. Some major sources of entropy increase are listed. An expanding "causal" region is defined in which the entropy, though increasing, tends to fall further and further behind its maximum possible value, thus allowing for the development of order. The related questions of whether entropy will continue increasing without limit in the future, and whether such increase in the form of Hawking radiation or radiation from positronium might enable life to maintain itself permanently, are considered. Attempts to find a scheme for preserving life based on solid structures fail because events such as quantum tunneling recurrently disorganize matter on a very long but fixed time scale, whereas all energy sources slow down progressively in an expanding universe. However, there remains hope that other modes of life capable of maintaining themselves permanently can be found.

  2. Economics and Maximum Entropy Production

    NASA Astrophysics Data System (ADS)

    Lorenz, R. D.

    2003-04-01

    Price differentials, sales volume and profit can be seen as analogues of temperature difference, heat flow and work or entropy production in the climate system. One aspect in which economic systems exhibit more clarity than the climate is that the empirical and/or statistical mechanical tendency for systems to seek a maximum in production is very evident in economics, in that the profit motive is very clear. Noting the common link between 1/f noise, power laws and Self-Organized Criticality with Maximum Entropy Production, the power law fluctuations in security and commodity prices is not inconsistent with the analogy. There is an additional thermodynamic analogy, in that scarcity is valued. A commodity concentrated among a few traders is valued highly by the many who do not have it. The market therefore encourages via prices the spreading of those goods among a wider group, just as heat tends to diffuse, increasing entropy. I explore some empirical price-volume relationships of metals and meteorites in this context.

  3. Entropy of random entangling surfaces

    NASA Astrophysics Data System (ADS)

    Solodukhin, Sergey N.

    2012-09-01

    We consider the situation when a globally defined four-dimensional field system is separated on two entangled sub-systems by a dynamical (random) two-dimensional surface. The reduced density matrix averaged over ensemble of random surfaces of fixed area and the corresponding average entropy are introduced. The average entanglement entropy is analyzed for a generic conformal field theory in four dimensions. Two important particular cases are considered. In the first, both the intrinsic metric on the entangling surface and the spacetime metric are fluctuating. An important example of this type is when the entangling surface is a black hole horizon, the fluctuations of which cause necessarily the fluctuations in the spacetime geometry. In the second case, the spacetime is considered to be fixed. The detailed analysis is carried out for the random entangling surfaces embedded in flat Minkowski spacetime. In all cases, the problem reduces to an effectively two-dimensional problem of random surfaces which can be treated by means of the well-known conformal methods. Focusing on the logarithmic terms in the entropy, we predict the appearance of a new ln ln(A) term. This article is part of a special issue of Journal of Physics A: Mathematical and Theoretical in honour of Stuart Dowker's 75th birthday devoted to ‘Applications of zeta functions and other spectral functions in mathematics and physics’.

  4. Entropy estimation in Turing's perspective.

    PubMed

    Zhang, Zhiyi

    2012-05-01

    A new nonparametric estimator of Shannon's entropy on a countable alphabet is proposed and analyzed against the well-known plug-in estimator. The proposed estimator is developed based on Turing's formula, which recovers distributional characteristics on the subset of the alphabet not covered by a size-n sample. The fundamental switch in perspective brings about substantial gain in estimation accuracy for every distribution with finite entropy. In general, a uniform variance upper bound is established for the entire class of distributions with finite entropy that decays at a rate of O(ln(n)/n) compared to O([ln(n)]2/n) for the plug-in. In a wide range of subclasses, the variance of the proposed estimator converges at a rate of O(1/n), and this rate of convergence carries over to the convergence rates in mean squared errors in many subclasses. Specifically, for any finite alphabet, the proposed estimator has a bias decaying exponentially in n. Several new bias-adjusted estimators are also discussed.

  5. Linearity of holographic entanglement entropy

    NASA Astrophysics Data System (ADS)

    Almheiri, Ahmed; Dong, Xi; Swingle, Brian

    2017-02-01

    We consider the question of whether the leading contribution to the entanglement entropy in holographic CFTs is truly given by the expectation value of a linear operator as is suggested by the Ryu-Takayanagi formula. We investigate this property by computing the entanglement entropy, via the replica trick, in states dual to superpositions of macroscopically distinct geometries and find it consistent with evaluating the expectation value of the area operator within such states. However, we find that this fails once the number of semi-classical states in the superposition grows exponentially in the central charge of the CFT. Moreover, in certain such scenarios we find that the choice of surface on which to evaluate the area operator depends on the density matrix of the entire CFT. This nonlinearity is enforced in the bulk via the homology prescription of Ryu-Takayanagi. We thus conclude that the homology constraint is not a linear property in the CFT. We also discuss the existence of `entropy operators' in general systems with a large number of degrees of freedom.

  6. Linearity of holographic entanglement entropy

    DOE PAGES

    Almheiri, Ahmed; Dong, Xi; Swingle, Brian

    2017-02-14

    Here, we consider the question of whether the leading contribution to the entanglement entropy in holographic CFTs is truly given by the expectation value of a linear operator as is suggested by the Ryu-Takayanagi formula. We investigate this property by computing the entanglement entropy, via the replica trick, in states dual to superpositions of macroscopically distinct geometries and find it consistent with evaluating the expectation value of the area operator within such states. However, we find that this fails once the number of semi-classical states in the superposition grows exponentially in the central charge of the CFT. Moreover, in certainmore » such scenarios we find that the choice of surface on which to evaluate the area operator depends on the density matrix of the entire CFT. This nonlinearity is enforced in the bulk via the homology prescription of Ryu-Takayanagi. We thus conclude that the homology constraint is not a linear property in the CFT. We also discuss the existence of entropy operators in general systems with a large number of degrees of freedom.« less

  7. Impaction of First Permanent Molars-Case Report.

    DTIC Science & Technology

    1982-06-10

    maxillary incisors . Impaction of first and second 6 molars is also reported as very uncommon. In a radiographic survey of 5,000 U.S. Army recruits, it was...second molar and fourth molar, maxillary central incisor and maxillary lateral incisor and maxillary first molar. Impacted mandibular central incisors ...old male patient sought treatment for discomfort during chewing on the left lower side of the jaw. A clinical examination revealed deep pocketing and

  8. Crowd macro state detection using entropy model

    NASA Astrophysics Data System (ADS)

    Zhao, Ying; Yuan, Mengqi; Su, Guofeng; Chen, Tao

    2015-08-01

    In the crowd security research area a primary concern is to identify the macro state of crowd behaviors to prevent disasters and to supervise the crowd behaviors. The entropy is used to describe the macro state of a self-organization system in physics. The entropy change indicates the system macro state change. This paper provides a method to construct crowd behavior microstates and the corresponded probability distribution using the individuals' velocity information (magnitude and direction). Then an entropy model was built up to describe the crowd behavior macro state. Simulation experiments and video detection experiments were conducted. It was verified that in the disordered state, the crowd behavior entropy is close to the theoretical maximum entropy; while in ordered state, the entropy is much lower than half of the theoretical maximum entropy. The crowd behavior macro state sudden change leads to the entropy change. The proposed entropy model is more applicable than the order parameter model in crowd behavior detection. By recognizing the entropy mutation, it is possible to detect the crowd behavior macro state automatically by utilizing cameras. Results will provide data support on crowd emergency prevention and on emergency manual intervention.

  9. Formal groups and Z-entropies

    NASA Astrophysics Data System (ADS)

    Tempesta, Piergiulio

    2016-11-01

    We shall prove that the celebrated Rényi entropy is the first example of a new family of infinitely many multi-parametric entropies. We shall call them the Z-entropies. Each of them, under suitable hypotheses, generalizes the celebrated entropies of Boltzmann and Rényi. A crucial aspect is that every Z-entropy is composable (Tempesta 2016 Ann. Phys. 365, 180-197. (doi:10.1016/j.aop.2015.08.013)). This property means that the entropy of a system which is composed of two or more independent systems depends, in all the associated probability space, on the choice of the two systems only. Further properties are also required to describe the composition process in terms of a group law. The composability axiom, introduced as a generalization of the fourth Shannon-Khinchin axiom (postulating additivity), is a highly non-trivial requirement. Indeed, in the trace-form class, the Boltzmann entropy and Tsallis entropy are the only known composable cases. However, in the non-trace form class, the Z-entropies arise as new entropic functions possessing the mathematical properties necessary for information-theoretical applications, in both classical and quantum contexts. From a mathematical point of view, composability is intimately related to formal group theory of algebraic topology. The underlying group-theoretical structure determines crucially the statistical properties of the corresponding entropies.

  10. Statistical mechanical theory of liquid entropy

    SciTech Connect

    Wallace, D.C.

    1993-07-01

    The multiparticle correlation expansion for the entropy of a classical monatomic liquid is presented. This entropy expresses the physical picture in which there is no free particle motion, but rather, each atom moves within a cage formed by its neighbors. The liquid expansion, including only pair correlations, gives an excellent account of the experimental entropy of most liquid metals, of liquid argon, and the hard sphere liquid. The pair correlation entropy is well approximated by a universal function of temperature. Higher order correlation entropy, due to n-particle irreducible correlations for n{ge}3, is significant in only a few liquid metals, and its occurrence suggests the presence of n-body forces. When the liquid theory is applied to the study of melting, the author discovers the important classification of normal and anomalous melting, according to whether there is not or is a significant change in the electronic structure upon melting, and he discovers the universal disordering entropy for melting of a monatomic crystal. Interesting directions for future research are: extension to include orientational correlations of molecules, theoretical calculation of the entropy of water, application to the entropy of the amorphous state, and correlational entropy of compressed argon. The author clarifies the relation among different entropy expansions in the recent literature.

  11. Formal groups and Z-entropies.

    PubMed

    Tempesta, Piergiulio

    2016-11-01

    We shall prove that the celebrated Rényi entropy is the first example of a new family of infinitely many multi-parametric entropies. We shall call them the Z-entropies. Each of them, under suitable hypotheses, generalizes the celebrated entropies of Boltzmann and Rényi. A crucial aspect is that every Z-entropy is composable (Tempesta 2016 Ann. Phys.365, 180-197. (doi:10.1016/j.aop.2015.08.013)). This property means that the entropy of a system which is composed of two or more independent systems depends, in all the associated probability space, on the choice of the two systems only. Further properties are also required to describe the composition process in terms of a group law. The composability axiom, introduced as a generalization of the fourth Shannon-Khinchin axiom (postulating additivity), is a highly non-trivial requirement. Indeed, in the trace-form class, the Boltzmann entropy and Tsallis entropy are the only known composable cases. However, in the non-trace form class, the Z-entropies arise as new entropic functions possessing the mathematical properties necessary for information-theoretical applications, in both classical and quantum contexts. From a mathematical point of view, composability is intimately related to formal group theory of algebraic topology. The underlying group-theoretical structure determines crucially the statistical properties of the corresponding entropies.

  12. Determination of the molar absorptivity of NADH.

    PubMed

    McComb, R B; Bond, L W; Burnett, R W; Keech, R C; Bowers, G N

    1976-02-01

    The molar absorptivity of NADH at 340 nm has been determined by an indirect procedure in which high-purity glucose is phosphorylated by ATP in the presence of hexokinase, coupled to oxidation of the glucose-6-phosphate by NAD+ in the presence of glucose-6-phosphate dehydrogenase. The average value from 85 independent determinations is 6317 liter mol-1 cm-1 at 25 degrees C and pH 7.8. The overall uncertainty is -4.0 to +5.5 ppt (6292 to 6352 liter mol-1 cm-1), based on a standard error of the mean of 0.48 ppt and an estimate of systematic error of -2.6 to +4.1 ppt. Effects of pH, buffer, and temperature on the molar absorptivity are also reported.

  13. Complications after mandibular third molar extraction.

    PubMed

    de Boer, M P; Raghoebar, G M; Stegenga, B; Schoen, P J; Boering, G

    1995-11-01

    The records of 1,797 patients were retrospectively examined to analyze the possible relationships between postoperative complications following mandibular third molar extraction and parameters such as age, sex, indication for surgery, position of the molar, surgical experience, surgical technique, and postoperative care. Older patients tended to suffer more often from complications. Surgery performed while there were signs of pericoronal inflammation also resulted in more complications. There was no statistically significant difference in the mean complication rate arising from surgery performed by staff members and the rate when surgery was performed by residents. There seems to be no reason for patients to return routinely for removal of resorbable sutures or other postoperative care because this practice does not result in a decrease in postoperative symptoms.

  14. Enzyme Molar Fractions: A Powerful Tool for Understanding Enzyme Kinetics.

    ERIC Educational Resources Information Center

    Serra, Juan L.; And Others

    1986-01-01

    Deduces the relationship between reduced velocity and molar fractions for productive enzyme complexes; obtains the mathematical expression of molar fractions for an enzyme with two specific binding sites per molecule; and proposes a useful plot to follow the dependence of enzyme molar fractions with the concentration of one of its ligands. (JN)

  15. Cusp expression of protostylid in deciduous and permanent molars.

    PubMed

    Moreno, Sandra; Reyes, María Paula; Moreno, Freddy

    2016-01-01

    The present article is a case report on the cusp expression of protostylid in the deciduous inferior molars and in the first permanent inferior molar, in which the correspondence and bilateral symmetry of the mentioned expression can be evidenced, as well as the their relation with the foramen cecum of the mesiobuccal furrows of the deciduous and of the permanent inferior molars.

  16. Cusp expression of protostylid in deciduous and permanent molars

    PubMed Central

    Moreno, Sandra; Reyes, María Paula; Moreno, Freddy

    2016-01-01

    The present article is a case report on the cusp expression of protostylid in the deciduous inferior molars and in the first permanent inferior molar, in which the correspondence and bilateral symmetry of the mentioned expression can be evidenced, as well as the their relation with the foramen cecum of the mesiobuccal furrows of the deciduous and of the permanent inferior molars. PMID:28123270

  17. Phase stability and microstructures of high entropy alloys ion irradiated to high doses

    NASA Astrophysics Data System (ADS)

    Xia, Songqin; Gao, Michael C.; Yang, Tengfei; Liaw, Peter K.; Zhang, Yong

    2016-11-01

    The microstructures of AlxCoCrFeNi (x = 0.1, 0.75 and 1.5 in molar ratio) high entropy alloys (HEAs) irradiated at room temperature with 3 MeV Au ions at the highest fluence of 105, 91, and 81 displacement per atom, respectively, were studied. Transmission electron microscopy (TEM) and high-resolution TEM (HRTEM) analyses show that the initial microstructures and phase composition of all three alloys are retained after ion irradiation and no phase decomposition is observed. Furthermore, it is demonstrated that the disordered face-centered cubic (FCC) and disordered body-centered cubic (BCC) phases show much less defect cluster formation and structural damage than the NiAl-type ordered B2 phase. This effect is explained by higher entropy of mixing, higher defect formation/migration energies, substantially lower thermal conductivity, and higher atomic level stress in the disordered phases.

  18. Pain control after third molar surgery.

    PubMed

    Seymour, R A; Walton, J G

    1984-12-01

    The ideal agent for use after third molar surgery should alleviate pain, reduce swelling and trismus to a minimum, promote healing and have no unwanted effects. Of course, such an agent does not exist. For relief of pain, analgesics are the obvious choice. Where possible, an analgesic with additional anti-inflammatory properties should be used. There seems little to choose between aspirin, 1000 mg; diflunisal, 500 mg; ibuprofen, 400 mg and zomepirac sodium, 50 mg. In the subject allergic to aspirin and aspirin-like compounds, then paracetamol is the poor alternative. Surprisingly, the efficacy of most of the opioids in post-operative third molar pain is poor, and these drugs alone cannot be recommended for this purpose. Long-acting local anaesthetic solutions may be of value in some situations where extreme pain is likely to be a feature in the immediate post-operative period. However, there are no strict criteria for identifying such cases pre-operatively. Recent work on the use of corticosteroids would suggest that these drugs may be of value in reducing post-operative sequelae. Their future in dentistry in this rôle appears interesting and promising, and worthy of further study. Antihistamines and enzymes have been shown to be of little value, and the fact that these agents now receive little attention is evidence in its own right. The use of locally applied antimicrobials has been shown to be of little value in third molar surgery. In any case, their use is probably contraindicated because of the risk of sensitising the patient. The studies reviewed have not pointed to the effectiveness of the routine use of systemic antimicrobials in preventing or reducing postoperative sequelae after removal of impacted third molars in normal circumstances. Particular conditions, for example in patients susceptible to infection, may benefit by the use of prophylactic antimicrobials. However, each case must be judged on its individual merits, bearing in mind the attendant

  19. Local entropy of a nonequilibrium fermion system

    NASA Astrophysics Data System (ADS)

    Stafford, Charles A.; Shastry, Abhay

    2017-03-01

    The local entropy of a nonequilibrium system of independent fermions is investigated and analyzed in the context of the laws of thermodynamics. It is shown that the local temperature and chemical potential can only be expressed in terms of derivatives of the local entropy for linear deviations from local equilibrium. The first law of thermodynamics is shown to lead to an inequality, not equality, for the change in the local entropy as the nonequilibrium state of the system is changed. The maximum entropy principle (second law of thermodynamics) is proven: a nonequilibrium distribution has a local entropy less than or equal to a local equilibrium distribution satisfying the same constraints. It is shown that the local entropy of the system tends to zero when the local temperature tends to zero, consistent with the third law of thermodynamics.

  20. Black Hole Entropy and the Renormalization Group

    NASA Astrophysics Data System (ADS)

    Satz, Alejandro; Jacobson, Ted

    2015-01-01

    Four decades after its first postulation by Bekenstein, black hole entropy remains mysterious. It has long been suggested that the entanglement entropy of quantum fields on the black hole gravitational background should represent at least an important contribution to the total Bekenstein-Hawking entropy, and that the divergences in the entanglement entropy should be absorbed in the renormalization of the gravitational couplings. In this talk, we describe how an improved understanding of black hole entropy is obtained by combining these notions with the renormalization group. By introducing an RG flow scale, we investigate whether the total entropy of the black hole can be partitioned in a "gravitational" part related to the flowing gravitational action, and a "quantum" part related to the unintegrated degrees of freedom. We describe the realization of this idea for free fields, and the complications and qualifications arising for interacting fields.

  1. Mutual entropy production in bipartite systems

    NASA Astrophysics Data System (ADS)

    Diana, Giovanni; Esposito, Massimiliano

    2014-04-01

    It was recently shown by Barato et al (2013 Phys. Rev. E 87 042104) that the mutual information at the trajectory level of a bipartite Markovian system is not bounded by the entropy production. In the same way as Gaspard showed (2004 J. Stat. Phys. 117 599) that the entropy production is not directly related to the Shannon entropy at the trajectory level but is in fact equal to its difference from the so-called time-reversed Shannon entropy, we show in this paper that the difference between the mutual information and its time-reversed form is equal to the mutual entropy production (MEP), i.e. the difference between the full entropy production and that of the two marginal processes. Evaluation of the MEP is in general a difficult task due to non-Markovian effects. For bipartite systems, we provide closed expressions in various limiting regimes which we verify by numerical simulations.

  2. The Moist Entropy Change in Tropical Cyclones

    NASA Astrophysics Data System (ADS)

    Juracic, Ana

    2012-10-01

    Important part of moist entropy budget is the advection of moist entropy in or out of the system, due to interaction of wind and moist entropy fields. The dropwindsonde data from several tropical storms is used to calculate both of those fields, as well as the resulting flow. In order to determine if the storm is exporting or importing moist entropy, the advection is horizontally averaged and vertically integrated. The storms of interest were Alex, Karl, Gaston and Fanapi from 2010. First three occurred in Atlantic basin while Fanapi evolved over Pacific basin. Gaston is the only one that was not developing during dropsonde missions, so it can be used as some kind of indicator of non-developing features in the entropy flux. The data show that during the development of the storm, the values of the moist entropy export are lower than for non-developing systems.

  3. Early introduction of entropy concepts in the first undergraduate course in thermodynamics

    SciTech Connect

    Smith, J.L. Jr.

    1996-12-31

    A new introductory course in mechanical engineering thermodynamics is described. The course develops the basic concepts as natural extensions of the students previous experience. The first law and the second law are developed simultaneously and with equal emphasis. Entropy, entropy transfer and entropy generation are introduced in a manner analogous to the introduction of energy, energy transfer and generation of heat. Extensive use is made of isolated systems for analysis so that all relevant relations are systematically identified. The PVT, energy and entropy constitutive relations for subsystems are presented separately from the first law and second law relations for a given problem. With the early introduction of entropy, all of the constitutive relations, including entropy, are described at the same time. The concept of mechanical-to-thermal cross coupling within the constitutive relations is introduced and related to the Maxwell-relation partial derivatives. The energy conversion requirement for cross coupling is developed. Control volume and flow system relations are developed from closed system relations in a conventional manner. The course ends with a description of the models for several important energy conversion plants and a discussion of the reason that all practical plants are flow systems.

  4. Orthodontic uprighting of a horizontally impacted third molar and protraction of mandibular second and third molars into the missing first molar space for a patient with posterior crossbites.

    PubMed

    Baik, Un-Bong; Kim, Myung-Rae; Yoon, Kyu-Ho; Kook, Yoon-Ah; Park, Jae Hyun

    2017-03-01

    A 22-year-old woman came with a unilateral missing mandibular first molar and buccal crossbite. The open space was closed by protraction of the mandibular left second molar and uprighting and protraction of the horizontally impacted third molar using temporary skeletal anchorage devices, and her buccal crossbite was corrected with modified palatal and lingual appliances. The total active treatment time was 36 months. Posttreatment records after 9 months showed excellent results with a stable occlusion.

  5. Entropy jump across an inviscid shock wave

    NASA Technical Reports Server (NTRS)

    Salas, Manuel D.; Iollo, Angelo

    1995-01-01

    The shock jump conditions for the Euler equations in their primitive form are derived by using generalized functions. The shock profiles for specific volume, speed, and pressure are shown to be the same, however density has a different shock profile. Careful study of the equations that govern the entropy shows that the inviscid entropy profile has a local maximum within the shock layer. We demonstrate that because of this phenomenon, the entropy, propagation equation cannot be used as a conservation law.

  6. Monitoring Brain Injury With TSALLIS Entropy

    DTIC Science & Technology

    2001-10-25

    significant but still remains to be studied. Literature has pointed to the role of q in the entropy computation for EEG studies [10]. In our study it is... EEG in the form of reduction during the bad physiological function outcome. The reduction level and recovery rate of TE are also consistent with...USA Abstract- Nonextensive entropy measure, Tsallis Entropy (TE), was undertaken to monitor the brain injury after cardiac arrest. EEG of human and

  7. Corrected Entropy of BTZ Black Holes

    NASA Astrophysics Data System (ADS)

    Farahani, Hoda; Sadeghi, Jafar; Saadat, Hassan

    2012-12-01

    In this paper, corrected entropy of a class of BTZ black holes, include charge and rotation, studied. We obtain corrected Bekenstein-Hawking entropy and find that effect of charge viewed at order A -2, and effect of rotation viewed at order A -6, therefore Q and J don't have contribution in corrected entropy lower than the second order. We also write the first law of black hole thermodynamics for the case of charged rotating BTZ black hole.

  8. Entropy modeling of sustainable development of megacities

    NASA Astrophysics Data System (ADS)

    Tyrsin, A. N.; Gevorgyan, G. G.

    2017-06-01

    The entropy approach of modeling multidimensional stochastic systems is described. It is based on the system representation as a multidimensional random vector and on the use of its differential entropy as a mathematical model. The possibilities of using this entropy model are considered for problems of monitoring the state of complex systems, including megacities, regions and critical infrastructure. Examples of practical implementation of the model are presented for the study of the sustainable development of megacities and regional environmental protection systems.

  9. Complications of third molar surgery and their management.

    PubMed

    Marciani, Robert D

    2012-09-01

    The frequency and severity of untoward events associated with surgical procedures are influenced by multiple factors that may be related to the procedure, patient, and/or surgeon. Not every third molar needs to be removed. Full bony impacted lower third molars well below the cervical margin of the second molar crowns should be considered for retention. Certain deviations from normal healing should be considered to be complications. Risk factors associated with third molar removal should be carefully established and explained to the patient. Third molar surgery has a predictable postsoperative course for the average patient.

  10. Molar tubal ectopic pregnancy: Report of two cases.

    PubMed

    Mbarki, Chaouki; Jerbi, Emna; Hsayaoui, Najeh; Zouari, Fatma; Ben Brahim, Ehsen; Oueslati, Hedhili

    2015-06-01

    Ectopic molar pregnancy is a rare occurrence and consequently not often considered as a diagnostic possibility. We report two cases of molar hydatidiform tubal pregnancy. Diagnosis of ectopic pregnancy was confirmed on clinical biological and sonographic investigations. Diagnosis of molar pregnancy was done on histopathology. The clinical course was favorable for both patients. Although rare, molar changes can occur at any site of an ectopic pregnancy. Clinical diagnosis of a molar pregnancy is difficult but histopathology is the gold standard for diagnosis. © 2014 The Authors. Journal of Obstetrics and Gynaecology Research © 2014 Japan Society of Obstetrics and Gynecology.

  11. The minimum entropy principle and task performance.

    PubMed

    Guastello, Stephen J; Gorin, Hillary; Huschen, Samuel; Peters, Natalie E; Fabisch, Megan; Poston, Kirsten; Weinberger, Kelsey

    2013-07-01

    According to the minimum entropy principle, efficient cognitive performance is produced with a neurocognitive strategy that involves a minimum of degrees of freedom. Although high performance is often regarded as consistent performance as well, some variability in performance still remains which allows the person to adapt to changing goal conditions or fatigue. The present study investigated the connection between performance, entropy in performance, and four task-switching strategies. Fifty-one undergraduates performed 7 different computer-based cognitive tasks producing sets of 49 responses under instructional conditions requiring task quotas or no quotas. The temporal patterns of performance were analyzed using orbital decomposition to extract pattern types and lengths, which were then compared with regard to Shannon entropy, topological entropy, and overall performance. Task switching strategies from a previous study were available for the same participants as well. Results indicated that both topological entropy and Shannon entropy were negatively correlated with performance. Some task-switching strategies produced lower entropy in performance than others. Stepwise regression showed that the top three predictors of performance were Shannon entropy and arithmetic and spatial abilities. Additional implications for the prediction of work performance with cognitive ability measurements and the applicability of the minimum entropy principle to multidimensional performance criteria and team work are discussed.

  12. Cyclic entropy: An alternative to inflationary cosmology

    NASA Astrophysics Data System (ADS)

    Frampton, Paul Howard

    2015-07-01

    We address how to construct an infinitely cyclic universe model. A major consideration is to make the entropy cyclic which requires the entropy to be reset to zero in each cycle expansion → turnaround → contraction → bounce → etc. Here, we reset entropy at the turnaround by selecting the introverse (visible universe) from the extroverse which is generated by the accelerated expansion. In the model, the observed homogeneity is explained by the low entropy at the bounce. The observed flatness arises from the contraction together with the reduction in size between the expanding and contracting universe. The present flatness is predicted to be very precise.

  13. Quantification Of Leakage In Microvessels Using Entropy

    NASA Astrophysics Data System (ADS)

    Desoky, Ahmed H.; O'Connor, Carol; Harris, Patrick D.; Hall, Steven

    1989-05-01

    This paper describes the use of entropy to quantify leakage of large molecules in a microvascular system. This measure can be used as a global parameter to characterize leakage. A software package for analysis of a sequence of images comprising leakage in rat cremaster tissue has been developed. The analysis is based on the statistics of both gray level components and frequency components of the images. Results show that entropy provides a better measure of leakage because it does not depend on variation in illumination or translation and rotation of image objects. Moreover entropy based on frequency components provides a more sensitive leakage measure than entropy based on gray level components.

  14. Three faces of entropy for complex systems: Information, thermodynamics, and the maximum entropy principle

    NASA Astrophysics Data System (ADS)

    Thurner, Stefan; Corominas-Murtra, Bernat; Hanel, Rudolf

    2017-09-01

    There are at least three distinct ways to conceptualize entropy: entropy as an extensive thermodynamic quantity of physical systems (Clausius, Boltzmann, Gibbs), entropy as a measure for information production of ergodic sources (Shannon), and entropy as a means for statistical inference on multinomial processes (Jaynes maximum entropy principle). Even though these notions represent fundamentally different concepts, the functional form of the entropy for thermodynamic systems in equilibrium, for ergodic sources in information theory, and for independent sampling processes in statistical systems, is degenerate, H (p ) =-∑ipilogpi . For many complex systems, which are typically history-dependent, nonergodic, and nonmultinomial, this is no longer the case. Here we show that for such processes, the three entropy concepts lead to different functional forms of entropy, which we will refer to as SEXT for extensive entropy, SIT for the source information rate in information theory, and SMEP for the entropy functional that appears in the so-called maximum entropy principle, which characterizes the most likely observable distribution functions of a system. We explicitly compute these three entropy functionals for three concrete examples: for Pólya urn processes, which are simple self-reinforcing processes, for sample-space-reducing (SSR) processes, which are simple history dependent processes that are associated with power-law statistics, and finally for multinomial mixture processes.

  15. Mechanically Alloyed High Entropy Composite

    NASA Astrophysics Data System (ADS)

    Popescu, G.; Adrian, M. M.; Csaki, I.; Popescu, C. A.; Mitrică, D.; Vasile, S.; Carcea, I.

    2016-08-01

    In the last years high entropy alloys have been investigated due to their high hardness, high temperature stability and unusual properties that make these alloys to have significant interest. In comparison with traditional alloys that are based on two or three major elements, this new generation alloys consists at least of 5 principal elements, with the concentration between 5 and 35 at.%. The present paper reports synthesis of high entropy alloys (HEA) and high entropy composites (HEC) synthesized by mechanical alloying (MA). The equiatomic AlCrFeNiMn matrix was used for creating the HEA matrix, starting from elemental powders and as reinforcing material for composites was used pure graphite. The mechanical alloying process was carried out at different duration, in a high energy planetary ball mill, under argon atmosphere. The elemental powders alloying began after '5 hours of milling and was complete after 40 hours. The mechanical alloyed matrix and composite was pressed and heat treated under argon protection. The elemental powers were investigated for physical - technological properties, and by X-ray diffraction and scanning electron microscopy. Phase pressing operation was realized with a hydraulic press and the applied pressure was progressive. The sintering process was carried out at 850°C for 2 h. The X-ray diffraction revealed that the MA process resulted in solid solutions formation and also revealed body- centred cubic (BCC) and face-centred cubic (FCC) structures with average grain size around 40 nm. In addition, nanoscale particles were highlighted by scanning electron microscopy, as well as the homogeneity of the chemical composition of the matrix and composite that was confirmed by EDX microanalysis. It was noted that HEA matrix and HEA composites were processed with a high degree of compaction and with a quite large capacity of mixed powder densification (around 70%).

  16. Assessment of the associated symptoms, pathologies, positions and angulations of bilateral occurring mandibular third molars: is there any similarity?

    PubMed

    Akarslan, Zühre Zafersoy; Kocabay, Ceyda

    2009-09-01

    The aim of this study was to evaluate and establish any similarity between the associated symptoms, pathologies, positions, and angulation types of bilateral occurring mandibular third molars among a group of young adult patients. A total of 342 patients (167 females, 175 males), aged between 20 and 25 years (mean: 22.2, SD: 1.8) participated in the study. Clinical and radiographic examinations were performed. Eruption status, mucosal and bony coverage type, presence of pain, pericoronitis, suppuration, ulceration, caries in third molar, distal caries in second molar, bone loss, root resorption, or cyst or tumor formation was investigated in addition to the position and the angulation of each tooth. Patients having at least one completely or partially erupted mandibular third molar were classified as group 1 and patients having bilateral impacted mandibular third molars were classified as group 2. No significant difference was found between the symptoms and pathologies related with the mandibular right third molar (RM) and the left third molar (LM) among both groups and genders (P > .05). In the total sample, no significant difference was found between the RM and the LM in terms of mucosal coverage type, bony coverage type, and position both in group 1 and group 2 (P > .05); but gender had an influence on the bony coverage type and ramus distance of the RM and the LM in group 2 (P < .05). In the total the sample, symmetry was present for horizontal or distoangular and vertical or distoangular angulations in group 1 and group 2, respectively. Gender was found to also have an impact on angulation symmetry. In most cases, a similarity was present between the symptoms and pathologies related with the bilateral mandibular third molars; but symmetry in position and angulation differed according to eruption status, angulation type, and gender.

  17. Rényi entropy perspective on topological order in classical toric code models

    NASA Astrophysics Data System (ADS)

    Helmes, Johannes; Stéphan, Jean-Marie; Trebst, Simon

    2015-09-01

    Concepts of information theory are increasingly used to characterize collective phenomena in condensed matter systems, such as the use of entanglement entropies to identify emergent topological order in interacting quantum many-body systems. Here, we employ classical variants of these concepts, in particular Rényi entropies and their associated mutual information, to identify topological order in classical systems. Like for their quantum counterparts, the presence of topological order can be identified in such classical systems via a universal, subleading contribution to the prevalent volume and boundary laws of the classical Rényi entropies. We demonstrate that an additional subleading O (1 ) contribution generically arises for all Rényi entropies S(n ) with n ≥2 when driving the system towards a phase transition, e.g., into a conventionally ordered phase. This additional subleading term, which we dub connectivity contribution, tracks back to partial subsystem ordering and is proportional to the number of connected parts in a given bipartition. Notably, the Levin-Wen summation scheme, typically used to extract the topological contribution to the Rényi entropies, does not fully eliminate this additional connectivity contribution in this classical context. This indicates that the distillation of topological order from Rényi entropies requires an additional level of scrutiny to distinguish topological from nontopological O (1 ) contributions. This is also the case for quantum systems, for which we discuss which entropies are sensitive to these connectivity contributions. We showcase these findings by extensive numerical simulations of a classical variant of the toric code model, for which we study the stability of topological order in the presence of a magnetic field and at finite temperatures from a Rényi entropy perspective.

  18. Modeling Partial Attacks with Alloy

    NASA Astrophysics Data System (ADS)

    Lin, Amerson; Bond, Mike; Clulow, Jolyon

    The automated and formal analysis of cryptographic primitives, security protocols and Application Programming Interfaces (APIs) up to date has been focused on discovering attacks that completely break the security of a system. However, there are attacks that do not immediately break a system but weaken the security sufficiently for the adversary. We term these attacks partial attacks and present the first methodology for the modeling and automated analysis of this genre of attacks by describing two approaches. The first approach reasons about entropy and was used to simulate and verify an attack on the ECB|ECB|OFB triple-mode DES block-cipher. The second approach reasons about possibility sets and was used to simulate and verify an attack on the personal identification number (PIN) derivation algorithm used in the IBM 4758 Common Cryptographic Architecture.

  19. Histopathology of the pulp of primary molars with active and arrested dentinal caries.

    PubMed

    Di Nicolo, R; Guedes-Pinto, A C; Carvalho, Y R

    2000-01-01

    The purpose of this study was to compare the histological appearance of the pulp of human primary molars with active and arrested lesions. The sample consisted of 36 primary molars (18 with active lesions and 18 with arrested lesions) extracted from 35 children between 5 to 9 years of age. The histological diagnosis was classified in normal pulp, transitional stage, partial pulpitis, total pulpitis and total necrosis, and then subdivided in three subgroups: treatable, untreatable and questionable. Results showed that normal pulp or transitional stage (treatable category) was diagnosed in 50% of teeth with arrested lesions, compared to 11.1% of teeth with active lesions. Partial pulpitis (questionable category) was present in 38.8% with arrested lesions compared to 22.2% with active lesions. Total pulpitis and total necrosis (untreatable category) was diagnosed in 11.2% with arrested lesions compared to 66.7% with active lesions. The observed frequencies of histological categories between both groups were statistically significant (P < 0.05). Histologically, pulp reaction under active and arrested lesions in primary molars revealed the formation of a basophilic calcio-traumatic line at the junction of the primary and reparative dentin, formation of reparative dentin and a regular odontoblastic layer in 60% of the cases. Results indicated that the type of lesion (active or arrested) is a good indicator of the histological status of the pulp.

  20. Impact of Entropy Generation on Stagnation-Point Flow of Sutterby Nanofluid: A Numerical Analysis

    NASA Astrophysics Data System (ADS)

    Azhar, Ehtsham; Iqbal, Z.; Maraj, E. N.

    2016-09-01

    The present article dicusses the computational analysis of entropy generation for the stagnation-point flow of Sutterby nanofluid over a linear stretching plate. The Sutterby fluid is chosen to study the effect for three major classes of non-Newtonian fluids, i.e. pseudoplastic, Newtonian, and dilatant. The effects of pertinent physical parameters are examined under the approximation of boundary layer. The system of coupled nonlinear partial differential equations is simplified by incorporating suitable similarity transformation into a system of non-linear-coupled ordinary differential equations. Entropy generation analysis is conducted numerically, and the results are displayed through graphs and tables. Significant findings are listed in the closing remarks.

  1. Clausius entropy for arbitrary bifurcate null surfaces

    NASA Astrophysics Data System (ADS)

    Baccetti, Valentina; Visser, Matt

    2014-02-01

    Jacobson’s thermodynamic derivation of the Einstein equations was originally applied only to local Rindler horizons. But at least some parts of that construction can usefully be extended to give meaningful results for arbitrary bifurcate null surfaces. As presaged in Jacobson’s original article, this more general construction sharply brings into focus the questions: is entropy objectively ‘real’? Or is entropy in some sense subjective and observer-dependent? These innocent questions open a Pandora’s box of often inconclusive debate. A consensus opinion, though certainly not universally held, seems to be that Clausius entropy (thermodynamic entropy, defined via a Clausius relation {\\rm{d}}S = \\unicode{x111} Q/T) should be objectively real, but that the ontological status of statistical entropy (Shannon or von Neumann entropy) is much more ambiguous, and much more likely to be observer-dependent. This question is particularly pressing when it comes to understanding Bekenstein entropy (black hole entropy). To perhaps further add to the confusion, we shall argue that even the Clausius entropy can often be observer-dependent. In the current article we shall conclusively demonstrate that one can meaningfully assign a notion of Clausius entropy to arbitrary bifurcate null surfaces—effectively defining a ‘virtual Clausius entropy’ for arbitrary ‘virtual (local) causal horizons’. As an application, we see that we can implement a version of the generalized second law (GSL) for this virtual Clausius entropy. This version of GSL can be related to certain (nonstandard) integral variants of the null energy condition. Because the concepts involved are rather subtle, we take some effort in being careful and explicit in developing our framework. In future work we will apply this construction to generalize Jacobson’s derivation of the Einstein equations.

  2. Time dependence of Hawking radiation entropy

    SciTech Connect

    Page, Don N.

    2013-09-01

    If a black hole starts in a pure quantum state and evaporates completely by a unitary process, the von Neumann entropy of the Hawking radiation initially increases and then decreases back to zero when the black hole has disappeared. Here numerical results are given for an approximation to the time dependence of the radiation entropy under an assumption of fast scrambling, for large nonrotating black holes that emit essentially only photons and gravitons. The maximum of the von Neumann entropy then occurs after about 53.81% of the evaporation time, when the black hole has lost about 40.25% of its original Bekenstein-Hawking (BH) entropy (an upper bound for its von Neumann entropy) and then has a BH entropy that equals the entropy in the radiation, which is about 59.75% of the original BH entropy 4πM{sub 0}{sup 2}, or about 7.509M{sub 0}{sup 2} ≈ 6.268 × 10{sup 76}(M{sub 0}/M{sub s}un){sup 2}, using my 1976 calculations that the photon and graviton emission process into empty space gives about 1.4847 times the BH entropy loss of the black hole. Results are also given for black holes in initially impure states. If the black hole starts in a maximally mixed state, the von Neumann entropy of the Hawking radiation increases from zero up to a maximum of about 119.51% of the original BH entropy, or about 15.018M{sub 0}{sup 2} ≈ 1.254 × 10{sup 77}(M{sub 0}/M{sub s}un){sup 2}, and then decreases back down to 4πM{sub 0}{sup 2} = 1.049 × 10{sup 77}(M{sub 0}/M{sub s}un){sup 2}.

  3. Gravitational entropies in LTB dust models

    NASA Astrophysics Data System (ADS)

    Sussman, Roberto A.; Larena, Julien

    2014-04-01

    We consider generic Lemaître-Tolman-Bondi (LTB) dust models to probe the gravitational entropy proposals of Clifton, Ellis and Tavakol (CET) and of Hosoya and Buchert (HB). We also consider a variant of the HB proposal based on a suitable quasi-local scalar weighted average. We show that the conditions for entropy growth for all proposals are directly related to a negative correlation of similar fluctuations of the energy density and Hubble scalar. While this correlation is evaluated locally for the CET proposal, it must be evaluated in a non-local domain dependent manner for the two HB proposals. By looking at the fulfilment of these conditions at the relevant asymptotic limits we are able to provide a well grounded qualitative description of the full time evolution and radial asymptotic scaling of the three entropies in generic models. The following rigorous analytic results are obtained for the three proposals: (i) entropy grows when the density growing mode is dominant, (ii) all ever-expanding hyperbolic models reach a stable terminal equilibrium characterized by an inhomogeneous entropy maximum in their late time evolution; (iii) regions with decaying modes and collapsing elliptic models exhibit unstable equilibria associated with an entropy minimum (iv) near singularities the CET entropy diverges while the HB entropies converge; (v) the CET entropy converges for all models in the radial asymptotic range, whereas the HB entropies only converge for models asymptotic to a Friedmann-Lemaître-Robertson-Walker background. The fact that different independent proposals yield fairly similar conditions for entropy production, time evolution and radial scaling in generic LTB models seems to suggest that their common notion of a ‘gravitational entropy’ may be a theoretically robust concept applicable to more general spacetimes.

  4. Time dependence of Hawking radiation entropy

    NASA Astrophysics Data System (ADS)

    Page, Don N.

    2013-09-01

    If a black hole starts in a pure quantum state and evaporates completely by a unitary process, the von Neumann entropy of the Hawking radiation initially increases and then decreases back to zero when the black hole has disappeared. Here numerical results are given for an approximation to the time dependence of the radiation entropy under an assumption of fast scrambling, for large nonrotating black holes that emit essentially only photons and gravitons. The maximum of the von Neumann entropy then occurs after about 53.81% of the evaporation time, when the black hole has lost about 40.25% of its original Bekenstein-Hawking (BH) entropy (an upper bound for its von Neumann entropy) and then has a BH entropy that equals the entropy in the radiation, which is about 59.75% of the original BH entropy 4πM02, or about 7.509M02 ≈ 6.268 × 1076(M0/Msolar)2, using my 1976 calculations that the photon and graviton emission process into empty space gives about 1.4847 times the BH entropy loss of the black hole. Results are also given for black holes in initially impure states. If the black hole starts in a maximally mixed state, the von Neumann entropy of the Hawking radiation increases from zero up to a maximum of about 119.51% of the original BH entropy, or about 15.018M02 ≈ 1.254 × 1077(M0/Msolar)2, and then decreases back down to 4πM02 = 1.049 × 1077(M0/Msolar)2.

  5. Natal primary molar: clinical and histological aspects.

    PubMed

    Ruschel, Henrique C; Spiguel, Monica H; Piccinini, Daniela D; Ferreira, Simone H; Feldens, Eliane G

    2010-06-01

    The authors report a case of natal primary molar in a healthy 14-day-old child. The diagnosis of the case and the treatment plan are discussed, as well as histological analyses of the natal tooth. The tooth presented an immature appearance, with high mobility and insertion only in soft tissue, and therefore the clinical option adopted was dental extraction. Histological analyses revealed enamel hypoplasia and dentin showing a typical tubular pattern without alterations. The soft tissue had young and richly vascularized pulp with areas of chronic inflammatory infiltration.

  6. Root growth during molar eruption in extant great apes.

    PubMed

    Kelley, Jay; Dean, Christopher; Ross, Sasha

    2009-01-01

    While there is gradually accumulating knowledge about molar crown formation and the timing of molar eruption in extant great apes, very little is known about root formation during the eruption process. We measured mandibular first and second molar root lengths in extant great ape osteological specimens that died while either the first or second molars were in the process of erupting. For most specimens, teeth were removed so that root lengths could be measured directly. When this was not possible, roots were measured radiographically. We were particularly interested in the variation in the lengths of first molar roots near the point of gingival emergence, so specimens were divided into early, middle and late phases of eruption based on the number of cusps that showed protein staining, with one or two cusps stained equated with immediate post-gingival emergence. For first molars at this stage, Gorilla has the longest roots, followed by Pongo and Pan. Variation in first molar mesial root lengths at this stage in Gorilla and Pan, which comprise the largest samples, is relatively low and represents no more than a few months of growth in both taxa. Knowledge of root length at first molar emergence permits an assessment of the contribution of root growth toward differences between great apes and humans in the age at first molar emergence. Root growth makes up a greater percentage of the time between birth and first molar emergence in humans than it does in any of the great apes.

  7. Taking advantage of an unerupted third molar: a case report.

    PubMed

    Pereira, Igor Figueiredo; Santiago, Fernando Zander Mucci; Sette-Dias, Augusto Cesar; Noronha, Vladimir Reimar Augusto de Souza

    2017-01-01

    Treatments with dental surgery seek to displace tooth to the correct position within the dental arch. To report a clinical case that took advantage of an unerupted third molar. A male patient, 18 years of age, was referred by his dentist to evaluate the third molars. The clinical exam revealed no visible lower third molars. The computed tomography (CT) exam showed the presence of a supernumerary tooth in the region of the mandibular ramus, on the left side, and impaction of the third molar, which was causing root resorption on the second molar, thus making it impossible to remain in the buccal cavity. The preferred option, therefore, was to remove both second molar and the supernumerary tooth, in addition to attaching a device to the third molar during surgery for further traction. After 12 months, the third molar reached the proper position. When a mandibular second permanent molar shows an atypical root resorption, an impacted third molar can effectively substitute the tooth by using an appropriate orthodontic-surgical approach.

  8. Clinical significance of computed tomography assessment for third molar surgery

    PubMed Central

    Nakamori, Kenji; Tomihara, Kei; Noguchi, Makoto

    2014-01-01

    Surgical extraction of the third molar is the most commonly performed surgical procedure in the clinical practice of oral surgery. Third molar surgery is warranted when there is inadequate space for eruption, malpositioning, or risk for cyst or odontogenic tumor formation. Preoperative assessment should include a detailed morphologic analysis of the third molar and its relationship to adjacent structures and surrounding tissues. Due to developments in medical engineering technology, computed tomography (CT) now plays a critical role in providing the clear images required for adequate assessment prior to third molar surgery. Removal of the maxillary third molar is associated with a risk for maxillary sinus perforation, whereas removal of the mandibular third molar can put patients at risk for a neurosensory deficit from damage to the lingual nerve or inferior alveolar nerve. Multiple factors, including demographic, anatomic, and treatment-related factors, influence the incidence of nerve injury during or following removal of the third molar. CT assessment of the third molar prior to surgery can identify some of these risk factors, such as the absence of cortication between the mandibular third molar and the inferior alveolar canal, prior to surgery to reduce the risk for nerve damage. This topic highlight presents an overview of the clinical significance of CT assessment in third molar surgery. PMID:25071882

  9. Bilateral maxillary fused second and third molars: a rare occurrence

    PubMed Central

    Liang, Rui-Zhen; Wu, Jin-Tao; Wu, You-Nong; Smales, Roger J; Hu, Ming; Yu, Jin-Hua; Zhang, Guang-Dong

    2012-01-01

    This case report describes the diagnosis and endodontic therapy of maxillary fused second and third molars, using cone-beam computed tomography (CBCT). A 31-year-old Chinese male, with no contributory medical or family/social history, presented with throbbing pain in the maxillary right molar area following an unsuccessful attempted tooth extraction. Clinical examination revealed what appeared initially to be a damaged large extra cusp on the buccal aspect of the distobuccal cusp of the second molar. However, CBCT revealed that a third molar was fused to the second molar. Unexpectedly, the maxillary left third molar also was fused to the second molar, and the crown of an unerupted supernumerary fourth molar was possibly also fused to the apical root region of the second molar. Operative procedures should not be attempted without adequate radiographic investigation. CBCT allowed the precise location of the root canals of the right maxillary fused molar teeth to permit successful endodontic therapy, confirmed after 6 months. PMID:23222992

  10. Ehrenfest's Lottery--Time and Entropy Maximization

    ERIC Educational Resources Information Center

    Ashbaugh, Henry S.

    2010-01-01

    Successful teaching of the Second Law of Thermodynamics suffers from limited simple examples linking equilibrium to entropy maximization. I describe a thought experiment connecting entropy to a lottery that mixes marbles amongst a collection of urns. This mixing obeys diffusion-like dynamics. Equilibrium is achieved when the marble distribution is…

  11. Chemical Engineering Students' Ideas of Entropy

    ERIC Educational Resources Information Center

    Haglund, Jesper; Andersson, Staffan; Elmgren, Maja

    2015-01-01

    Thermodynamics, and in particular entropy, has been found to be challenging for students, not least due to its abstract character. Comparisons with more familiar and concrete domains, by means of analogy and metaphor, are commonly used in thermodynamics teaching, in particular the metaphor "entropy is disorder." However, this particular…

  12. Entropy and Certainty in Lossless Data Compression

    ERIC Educational Resources Information Center

    Jacobs, James Jay

    2009-01-01

    Data compression is the art of using encoding techniques to represent data symbols using less storage space compared to the original data representation. The encoding process builds a relationship between the entropy of the data and the certainty of the system. The theoretical limits of this relationship are defined by the theory of entropy in…

  13. Campbell's Rule for Estimating Entropy Changes

    ERIC Educational Resources Information Center

    Jensen, William B.

    2004-01-01

    Campbell's rule for estimating entropy changes is discussed in relation to an earlier article by Norman Craig, where it was proposed that the approximate value of the entropy of reaction was related to net moles of gas consumed or generated. It was seen that the average for Campbell's data set was lower than that for Craig's data set and…

  14. Campbell's Rule for Estimating Entropy Changes

    ERIC Educational Resources Information Center

    Jensen, William B.

    2004-01-01

    Campbell's rule for estimating entropy changes is discussed in relation to an earlier article by Norman Craig, where it was proposed that the approximate value of the entropy of reaction was related to net moles of gas consumed or generated. It was seen that the average for Campbell's data set was lower than that for Craig's data set and…

  15. Generalized Entropic Uncertainty Relations with Tsallis' Entropy

    NASA Technical Reports Server (NTRS)

    Portesi, M.; Plastino, A.

    1996-01-01

    A generalization of the entropic formulation of the Uncertainty Principle of Quantum Mechanics is considered with the introduction of the q-entropies recently proposed by Tsallis. The concomitant generalized measure is illustrated for the case of phase and number operators in quantum optics. Interesting results are obtained when making use of q-entropies as the basis for constructing generalized entropic uncertainty measures.

  16. Entropy and Information: A Multidisciplinary Overview.

    ERIC Educational Resources Information Center

    Shaw, Debora; Davis, Charles H.

    1983-01-01

    Cites representative extensions of concept of entropy (measure of the amount of energy unavailable for useful work; from the second law of thermodynamics) noting basic relationships between entropy, order, information, and meaning in such disciplines as biology, economics, information science, the arts, and religion. Seventy-eight references are…

  17. Entropy Generation in a Chemical Reaction

    ERIC Educational Resources Information Center

    Miranda, E. N.

    2010-01-01

    Entropy generation in a chemical reaction is analysed without using the general formalism of non-equilibrium thermodynamics at a level adequate for advanced undergraduates. In a first approach to the problem, the phenomenological kinetic equation of an elementary first-order reaction is used to show that entropy production is always positive. A…

  18. Entropy estimation of very short symbolic sequences

    NASA Astrophysics Data System (ADS)

    Lesne, Annick; Blanc, Jean-Luc; Pezard, Laurent

    2009-04-01

    While entropy per unit time is a meaningful index to quantify the dynamic features of experimental time series, its estimation is often hampered in practice by the finite length of the data. We here investigate the performance of entropy estimation procedures, relying either on block entropies or Lempel-Ziv complexity, when only very short symbolic sequences are available. Heuristic analytical arguments point at the influence of temporal correlations on the bias and statistical fluctuations, and put forward a reduced effective sequence length suitable for error estimation. Numerical studies are conducted using, as benchmarks, the wealth of different dynamic regimes generated by the family of logistic maps and stochastic evolutions generated by a Markov chain of tunable correlation time. Practical guidelines and validity criteria are proposed. For instance, block entropy leads to a dramatic overestimation for sequences of low entropy, whereas it outperforms Lempel-Ziv complexity at high entropy. As a general result, the quality of entropy estimation is sensitive to the sequence temporal correlation hence self-consistently depends on the entropy value itself, thus promoting a two-step procedure. Lempel-Ziv complexity is to be preferred in the first step and remains the best estimator for highly correlated sequences.

  19. Entropy estimation of very short symbolic sequences.

    PubMed

    Lesne, Annick; Blanc, Jean-Luc; Pezard, Laurent

    2009-04-01

    While entropy per unit time is a meaningful index to quantify the dynamic features of experimental time series, its estimation is often hampered in practice by the finite length of the data. We here investigate the performance of entropy estimation procedures, relying either on block entropies or Lempel-Ziv complexity, when only very short symbolic sequences are available. Heuristic analytical arguments point at the influence of temporal correlations on the bias and statistical fluctuations, and put forward a reduced effective sequence length suitable for error estimation. Numerical studies are conducted using, as benchmarks, the wealth of different dynamic regimes generated by the family of logistic maps and stochastic evolutions generated by a Markov chain of tunable correlation time. Practical guidelines and validity criteria are proposed. For instance, block entropy leads to a dramatic overestimation for sequences of low entropy, whereas it outperforms Lempel-Ziv complexity at high entropy. As a general result, the quality of entropy estimation is sensitive to the sequence temporal correlation hence self-consistently depends on the entropy value itself, thus promoting a two-step procedure. Lempel-Ziv complexity is to be preferred in the first step and remains the best estimator for highly correlated sequences.

  20. Ehrenfest's Lottery--Time and Entropy Maximization

    ERIC Educational Resources Information Center

    Ashbaugh, Henry S.

    2010-01-01

    Successful teaching of the Second Law of Thermodynamics suffers from limited simple examples linking equilibrium to entropy maximization. I describe a thought experiment connecting entropy to a lottery that mixes marbles amongst a collection of urns. This mixing obeys diffusion-like dynamics. Equilibrium is achieved when the marble distribution is…

  1. The Origins of the Entropy Concept

    NASA Astrophysics Data System (ADS)

    Darrigol, Olivier

    To this day entropy remains a strange, difficult, and multiform concept. Even the great Henri Poincaré renounced precisely defining energy and entropy. In order to justify the success of the two laws of thermodynamics for his students at the Sorbonne, he turned to history:

  2. Chemical Engineering Students' Ideas of Entropy

    ERIC Educational Resources Information Center

    Haglund, Jesper; Andersson, Staffan; Elmgren, Maja

    2015-01-01

    Thermodynamics, and in particular entropy, has been found to be challenging for students, not least due to its abstract character. Comparisons with more familiar and concrete domains, by means of analogy and metaphor, are commonly used in thermodynamics teaching, in particular the metaphor "entropy is disorder." However, this particular…

  3. Rudolf Clausius and the road to entropy

    NASA Astrophysics Data System (ADS)

    Cropper, William H.

    1986-12-01

    That Rudolf Clausius invented the entropy concept is well known, but less familiar is the argument that served as his inspiration. This paper traces the development of Clausius' ``transformation theory'' of heat, which finally persuaded him to define the measure of transformation equivalence he called entropy.

  4. Invariant of dynamical systems: A generalized entropy

    SciTech Connect

    Meson, A.M.; Vericat, F. |

    1996-09-01

    In this work the concept of entropy of a dynamical system, as given by Kolmogorov, is generalized in the sense of Tsallis. It is shown that this entropy is an isomorphism invariant, being complete for Bernoulli schemes. {copyright} {ital 1996 American Institute of Physics.}

  5. Entropy Generation in a Chemical Reaction

    ERIC Educational Resources Information Center

    Miranda, E. N.

    2010-01-01

    Entropy generation in a chemical reaction is analysed without using the general formalism of non-equilibrium thermodynamics at a level adequate for advanced undergraduates. In a first approach to the problem, the phenomenological kinetic equation of an elementary first-order reaction is used to show that entropy production is always positive. A…

  6. Entropy and Certainty in Lossless Data Compression

    ERIC Educational Resources Information Center

    Jacobs, James Jay

    2009-01-01

    Data compression is the art of using encoding techniques to represent data symbols using less storage space compared to the original data representation. The encoding process builds a relationship between the entropy of the data and the certainty of the system. The theoretical limits of this relationship are defined by the theory of entropy in…

  7. Mechanics analysis of molar tooth splitting.

    PubMed

    Barani, Amir; Chai, Herzl; Lawn, Brian R; Bush, Mark B

    2015-03-01

    A model for the splitting of teeth from wedge loading of molar cusps from a round indenting object is presented. The model is developed in two parts: first, a simple 2D fracture mechanics configuration with the wedged tooth simulated by a compact tension specimen; second, a full 3D numerical analysis using extended finite element modeling (XFEM) with an embedded crack. The result is an explicit equation for splitting load in terms of indenter radius and key tooth dimensions. Fracture experiments on extracted human molars loaded axially with metal spheres are used to quantify the splitting forces and thence to validate the model. The XFEM calculations enable the complex crack propagation, initially in the enamel coat and subsequently in the interior dentin, to be followed incrementally with increasing load. The fracture evolution is shown to be stable prior to failure, so that dentin toughness, not strength, is the controlling material parameter. Critical conditions under which tooth splitting in biological and dental settings are likely to be met, however rare, are considered.

  8. Onset of molar incisor hypomineralization (MIH).

    PubMed

    Fagrell, Tobias G; Salmon, Phil; Melin, Lisa; Norén, Jörgen G

    2013-01-01

    The etiological factors and timing of the onset of molar incisor hypomineralization (MIH) are still not clear. The aim of this study was to examine ground radial and sagittal sections from teeth diagnosed with MIH using light microscopy, polarized light microscopy and X-ray micro-computed tomography (XMCT) and to estimate the onset and timing of the MIH and to relate the hypomineralized enamel to the incremental lines. Thirteen extracted permanent first molars diagnosed MIH, were analyzed with light microscopy and XMCT. The hypomineralized areas were mainly located in the mesio-buccal cusps, starting at the enamel-dentin-junction and continuing towards the enamel surface. In a relative gray scale analysis the values decreased from the EDJ towards the enamel surface. The findings indicate that the ameloblasts in the hypomineralized enamel are capable of forming an enamel of normal thickness, but with a substantial reduction of their capacity for maturation of enamel. Chronologically, it is estimated that the timing of the disturbance is at a period during the first 6-7 months of age.

  9. Antibiotic therapy in impacted third molar surgery.

    PubMed

    Monaco, G; Staffolani, C; Gatto, M R; Checchi, L

    1999-12-01

    The use of routine antibiotic therapy in patients undergoing surgical third molar extraction is controversial. The efficacy of antibiotic therapy in preventing postoperative complications following surgical third molar extractions was evaluated in 141 patients. In the test group (66 patients), the protocol utilized a regimen of 2 g of amoxicillin orally daily for 5 d postoperatively, starting at the completion of surgery. In the control group (75 patients), no antibiotic therapy was given. No significant difference was found between the test group and the control group in the incidence of postoperative sequelae, i.e. fever, pain, swelling and alveolar osteitis. A statistically significant association between smoking, habitual drinking and increased postoperative pain and fever was found. Patient age > or = 18 yr was positively correlated with an increased incidence of alveolar osteitis. Swelling was found to be gender-related, in that female patients experienced more swelling than male patients. No correlation was found between the time required for surgery or difficulty of extraction and post-operative pain. In conclusion, no difference was found between patients receiving postoperative amoxicillin and the control group in the incidence of postoperative sequelae.

  10. Evaluation of tribological behavior of Al-Co-Cr-Fe-Ni high entropy alloy using molecular dynamics simulation.

    PubMed

    Huang, Jen-Ching

    2012-01-01

    High-entropy alloys have been studied extensively for their excellent properties and performance, including outstanding strength and resistance to oxidation at high temperatures. This study employed molecular dynamics simulation to produce a high-entropy alloy containing an equal molar ratio of Al, Co, Cr, Fe, and Ni and investigated the tribological behavior of the material using a diamond tool in a vacuum environment. We also simulated a AlCoCrFeNi high-entropy alloy cooled from a high temperature molten state to 300 K in a high-speed quenching process to produce an amorphous microstructure. In a simulation of nanoscratching, the cutting force-distance curve of high-entropy alloys was used to evaluate work hardening and stick-slip. An increase in temperature was shown to reduce the scratching force and scratching resistance. Nanoscratching the high-entropy alloy at elevated temperatures provided evidence of work hardening; however, the degree of work hardening decreased with an increase in temperature. And it can also be found that when the temperature is higher, the fluctuation of the cutting force curve is greater.

  11. Entropy production in a photovoltaic cell

    NASA Astrophysics Data System (ADS)

    Ansari, Mohammad H.

    2017-05-01

    We evaluate entropy production in a photovoltaic cell that is modeled by four electronic levels resonantly coupled to thermally populated field modes at different temperatures. We use a formalism recently proposed, the so-called multiple parallel worlds, to consistently address the nonlinearity of entropy in terms of density matrix. Our result shows that entropy production is the difference between two flows: a semiclassical flow that linearly depends on occupational probabilities, and another flow that depends nonlinearly on quantum coherence and has no semiclassical analog. We show that entropy production in the cells depends on environmentally induced decoherence time and energy detuning. We characterize regimes where reversal flow of information takes place from a cold to hot bath. Interestingly, we identify a lower bound on entropy production, which sets limitations on the statistics of dissipated heat in the cells.

  12. Entanglement entropy in top-down models

    NASA Astrophysics Data System (ADS)

    Jones, Peter A. R.; Taylor, Marika

    2016-08-01

    We explore holographic entanglement entropy in ten-dimensional supergravity solutions. It has been proposed that entanglement entropy can be computed in such top-down models using minimal surfaces which asymptotically wrap the compact part of the geometry. We show explicitly in a wide range of examples that the holographic entan-glement entropy thus computed agrees with the entanglement entropy computed using the Ryu-Takayanagi formula from the lower-dimensional Einstein metric obtained from reduc-tion over the compact space. Our examples include not only consistent truncations but also cases in which no consistent truncation exists and Kaluza-Klein holography is used to identify the lower-dimensional Einstein metric. We then give a general proof, based on the Lewkowycz-Maldacena approach, of the top-down entanglement entropy formula.

  13. Low Streamflow Forcasting using Minimum Relative Entropy

    NASA Astrophysics Data System (ADS)

    Cui, H.; Singh, V. P.

    2013-12-01

    Minimum relative entropy spectral analysis is derived in this study, and applied to forecast streamflow time series. Proposed method extends the autocorrelation in the manner that the relative entropy of underlying process is minimized so that time series data can be forecasted. Different prior estimation, such as uniform, exponential and Gaussian assumption, is taken to estimate the spectral density depending on the autocorrelation structure. Seasonal and nonseasonal low streamflow series obtained from Colorado River (Texas) under draught condition is successfully forecasted using proposed method. Minimum relative entropy determines spectral of low streamflow series with higher resolution than conventional method. Forecasted streamflow is compared to the prediction using Burg's maximum entropy spectral analysis (MESA) and Configurational entropy. The advantage and disadvantage of each method in forecasting low streamflow is discussed.

  14. Trends of stellar entropy along stellar evolution

    NASA Astrophysics Data System (ADS)

    de Avellar, Guilherme Bronzato, Marcio; Alvares de Souza, Rodrigo; Horvath, Jorge Ernesto

    2016-02-01

    This paper is devoted to discussing the difference in the thermodynamic entropy budget per baryon in each type of stellar object found in the Universe. We track and discuss the actual decrease of the stored baryonic thermodynamic entropy from the most primitive molecular cloud up to the final fate of matter in black holes, passing through evolved states of matter as found in white dwarfs and neutron stars. We then discuss the case of actual stars with different masses throughout their evolution, clarifying the role of the virial equilibrium condition for the decrease in entropy and related issues. Finally, we discuss the role of gravity in driving the composition and the structural changes of stars with different Main Sequence masses during their evolution up to the final product. Particularly, we discuss the entropy of a black hole in this context arguing that the dramatic increase in its entropy, differently from the other cases, is due to the gravitational field itself.

  15. The role of entropy in magnetotail dynamics

    SciTech Connect

    Birn, Joachim; Zaharia, Sorin; Hesse, Michael

    2008-01-01

    The role of entropy conservation and loss in magnetospheric dynamics, particularly in relation to substorm phases, is discussed on the basis of MHD theory and simulations, using comparisons with PIC simulations for validation. Entropy conservation appears to be a crucial element leading to the formation of thin embedded current sheets in the late substorm growth phase and the potential loss of equilibrium. Entropy loss (in the form of plasmoids) is essential in the earthward transport of flux tubes (bubbles, bursty bulk flows). Entropy loss also changes the tail stability properties and may render ballooning modes unstable and thus contribute to cross-tail variability. We illustrate these effects through results from theory and simulations. Entropy conservation also governs the accessibility of final states of evolution and the amount of energy that may be released.

  16. Compressive sensing and entropy in seismic signals

    NASA Astrophysics Data System (ADS)

    Marinho, Eberton S.; Rocha, Tiago C.; Corso, Gilberto; Lucena, Liacir S.

    2017-09-01

    This work analyzes the correlation between the seismic signal entropy and the Compressive Sensing (CS) recovery index. The recovery index measures the quality of a signal reconstructed by the CS method. We analyze the performance of two CS algorithms: the ℓ1-MAGIC and the Fast Bayesian Compressive Sensing (BCS). We have observed a negative correlation between the performance of CS and seismic signal entropy. Signals with low entropy have small recovery index in their reconstruction by CS. The rationale behind our finding is: a sparse signal is easy to recover by CS and, besides, a sparse signal has low entropy. In addition, ℓ1-MAGIC shows a more significant correlation between entropy and CS performance than Fast BCS.

  17. Axiomatic Relation between Thermodynamic and Information-Theoretic Entropies

    NASA Astrophysics Data System (ADS)

    Weilenmann, Mirjam; Kraemer, Lea; Faist, Philippe; Renner, Renato

    2016-12-01

    Thermodynamic entropy, as defined by Clausius, characterizes macroscopic observations of a system based on phenomenological quantities such as temperature and heat. In contrast, information-theoretic entropy, introduced by Shannon, is a measure of uncertainty. In this Letter, we connect these two notions of entropy, using an axiomatic framework for thermodynamics [E. H. Lieb and J. Yngvason Proc. R. Soc. 469, 20130408 (2013)]. In particular, we obtain a direct relation between the Clausius entropy and the Shannon entropy, or its generalization to quantum systems, the von Neumann entropy. More generally, we find that entropy measures relevant in nonequilibrium thermodynamics correspond to entropies used in one-shot information theory.

  18. The predictivity of mandibular third molar position as a risk indicator for pericoronitis.

    PubMed

    Yamalik, Kemal; Bozkaya, Süleyman

    2008-03-01

    The aim of this study was to describe the characteristics of the mandibular third molar at highest risk for acute pericoronitis using clinical and radiographic analysis. A total of 102 volunteers, including 40 (39%) male and 62 (60%) female patients presenting with acute pericoronitis, participated in the study. The mean age of the participants was 23.4 years (range 17-30 years). The variables tested included the percentage of soft tissue coverage, availability of impinging maxillary dentition, and the angulation and eruption level of the mandibular third molar. While vertical impaction was the most frequent angulation (51%), horizontal impaction was quite rare (3%). Mesioangular impaction (25%) was slightly higher than distoangular impaction (21%). Difference between type of angulation was statistically significant for all groups (p < 0.05). The frequency of partial soft tissue coverage, particularly 75% coverage, was far more observed than the full soft tissue coverage (47%). The difference for the amount of soft tissue coverage was statistically significant (p < 0.05). In 57% of the cases, pericoronitis was associated with the third molars that erupted at the same level of the adjacent tooth occlusal plane. The difference among the three levels of eruption was significant (p < 0.000). Impinging maxillary dentition did not have a significant impact on development of pericoronitis (41%). Evidence of impinging maxillary dentition did not have a statistically significant impact on presence of pericoronitis (p = 0.075). Mandibular third molars at or near to the same level of the occlusal plane of the arch and exhibiting vertical inclination were considered at highest risk for developing pericoronitis. Such third molars can be given high priority for prophylactic care due to the possibility of severe consequences of acute pericoronitis.

  19. Entropy of uremia and dialysis technology.

    PubMed

    Ronco, Claudio

    2013-01-01

    The second law of thermodynamics applies with local exceptions to patient history and therapy interventions. Living things preserve their low level of entropy throughout time because they receive energy from their surroundings in the form of food. They gain their order at the expense of disordering the nutrients they consume. Death is the thermodynamically favored state: it represents a large increase in entropy as molecular structure yields to chaos. The kidney is an organ dissipating large amounts of energy to maintain the level of entropy of the organism as low as possible. Diseases, and in particular uremia, represent conditions of rapid increase in entropy. Therapeutic strategies are oriented towards a reduction in entropy or at least a decrease in the speed of entropy increase. Uremia is a process accelerating the trend towards randomness and disorder (increase in entropy). Dialysis is a factor external to the patient that tends to reduce the level of entropy caused by kidney disease. Since entropy can only increase in closed systems, energy and work must be spent to limit the entropy of uremia. This energy should be adapted to the system (patient) and be specifically oriented and personalized. This includes a multidimensional effort to achieve an adequate dialysis that goes beyond small molecular weight solute clearance. It includes a biological plan for recovery of homeostasis and a strategy towards long-term rehabilitation of the patient. Such objectives can be achieved with a combination of technology and innovation to answer specific questions that are still present after 60 years of dialysis history. This change in the individual bioentropy may represent a local exception to natural trends as the patient could be considered an isolated universe responding to the classic laws of thermodynamics.

  20. Survival of sealants in molars affected by molar-incisor hypomineralization: 18-month follow-up.

    PubMed

    Fragelli, Camila Maria Bullio; Souza, Juliana Feltrin de; Bussaneli, Diego Girotto; Jeremias, Fabiano; Santos-Pinto, Lourdes Dos; Cordeiro, Rita de Cássia Loiola

    2017-04-27

    The objective of this study was to evaluate the clinical survival of sealants applied in first permanent molars (FPMs) affected by molar-incisor hypomineralization (MIH), at 18 months of follow-up. Forty-one first permanent molars were selected from 21 children, 6-8 years of age. MIH was classified by one calibrated examiner (kappa = 0.80) according to EAPD criteria. The inclusion criteria were fully erupted FPMs with MIH or sound FPMs (without MIH) for which sealant treatment was indicated. The FPMs were assigned to two groups: CG (control group) and HG (MIH group). Both groups were treated with sealant (FluroShield). Clinical follow-up was performed from baseline to 18 months to assess anatomical form, marginal adaptation, retention and presence of caries, according to criteria set by the United States Public Health Service-Modified, and was conducted by a blinded examiner (kappa = 0.80). The actuarial method was used to evaluate the survival of the sealants. The survival rates for the groups were compared using Fisher's exact test (α = 5%). The cumulative survival rates were 81% at 1 month, 68.8% at 6 months, 68.8% at 12 months, and 62.6% at 18 months for CG, and 88% at 1 month, 84% at 6 months, 76% at 12 months, and 72% at 18 months for HG. No significant difference was found between the groups. The sealants in molars affected by MIH presented a survival rate similar to the sealants in the control, suggesting that sealants may be an adequate approach for preventing carious lesions in MIH-affected molars.

  1. Entropy Splitting and Numerical Dissipation

    NASA Technical Reports Server (NTRS)

    Yee, H. C.; Vinokur, M.; Djomehri, M. J.

    1999-01-01

    A rigorous stability estimate for arbitrary order of accuracy of spatial central difference schemes for initial-boundary value problems of nonlinear symmetrizable systems of hyperbolic conservation laws was established recently by Olsson and Oliger (1994) and Olsson (1995) and was applied to the two-dimensional compressible Euler equations for a perfect gas by Gerritsen and Olsson (1996) and Gerritsen (1996). The basic building block in developing the stability estimate is a generalized energy approach based on a special splitting of the flux derivative via a convex entropy function and certain homogeneous properties. Due to some of the unique properties of the compressible Euler equations for a perfect gas, the splitting resulted in the sum of a conservative portion and a non-conservative portion of the flux derivative. hereafter referred to as the "Entropy Splitting." There are several potential desirable attributes and side benefits of the entropy splitting for the compressible Euler equations that were not fully explored in Gerritsen and Olsson. The paper has several objectives. The first is to investigate the choice of the arbitrary parameter that determines the amount of splitting and its dependence on the type of physics of current interest to computational fluid dynamics. The second is to investigate in what manner the splitting affects the nonlinear stability of the central schemes for long time integrations of unsteady flows such as in nonlinear aeroacoustics and turbulence dynamics. If numerical dissipation indeed is needed to stabilize the central scheme, can the splitting help minimize the numerical dissipation compared to its un-split cousin? Extensive numerical study on the vortex preservation capability of the splitting in conjunction with central schemes for long time integrations will be presented. The third is to study the effect of the non-conservative proportion of splitting in obtaining the correct shock location for high speed complex shock

  2. Pattern of mandibular third molar impaction and its association to caries in mandibular second molar: A clinical variant.

    PubMed

    Prajapati, V K; Mitra, Ruchi; Vinayak, K M

    2017-01-01

    Caries in second molar is common and prophylactic removal of the impacted teeth may be considered appropriate. Caries detection and restoration can be difficult and a restored second molar can undergo recurrent caries if the third molar is not removed prophylactically. In this study, the clinical findings related to impaction and its association with angular position and depth of impacted third molar were evaluated. A retrospective descriptive study was carried out among the patients visiting the outpatient, department of Dentistry, RIMS, Ranchi. The clinical examination, periapical radiographs and Pre-op OPG were taken. Teeth positions were analyzed by Pell and Gregory and Winter classification. The angulation and depth of mandibular third molar impaction and caries in the second molar with the eruption status of the mandibular third molar was determined. A total of 200 patients were included in the study between age group 17-45 years. Majority of the Patients reported to the hospital with complaints of decayed tooth (66%) and pain (59%). The most common third molar impaction was mesioangular followed by distoangular. A statistically highly significant difference (P = 0.001) was obtained with the presence of caries in second molar adjacent to mesioangular third molar in class I and level B. According to this study, pattern of mandibular third molar impaction is in association to caries in mandibular second molar. More future studies are needed. In addition, the results of the present study can be used to screen and inform the patients about the possibility of caries in relation to third molar mandibular impaction.

  3. Molar mass distribution and solubility modeling of asphaltenes

    SciTech Connect

    Yarranton, H.W.; Masliyah, J.H.

    1996-12-01

    Attempts to model asphaltene solubility with Scatchard-Hildebrand theory were hampered by uncertainty in molar volume and solubility parameter distribution within the asphaltenes. By considering asphaltenes as a series of polyaromatic hydrocarbons with randomly distributed associated functional groups, molar volume and solubility parameter distributions are calculated from experimental measurements of molar mass and density. The molar mass distribution of Athabasca asphaltenes is determined from interfacial tension and vapor pressure osmometry measurements together with plasma desorption mass spectrometry determinations from the literature. Asphaltene densities are calculated indirectly from mixtures of known concentration of asphaltene in toluene. Asphaltene density, molar volume, and solubility parameter are correlated with molar mass. Solid-liquid equilibrium calculations based on solubility theory and the asphaltene property correlations successfully predict experimental data for both the precipitation point and the amount of precipitated asphaltenes in toluene-hexane solvent mixtures.

  4. Kissing molars extraction: Case series and review of the literature.

    PubMed

    Arjona-Amo, Manuel; Torres-Carranza, Eusebio; Batista-Cruzado, Antonio; Serrera-Figallo, Maria-Angeles; Crespo-Torres, Santos; Belmonte-Caro, Rodolfo; Albisu-Andrade, Claudio; Torres-Lagares, Daniel; Gutiérrez-Pérez, José-Luis

    2016-02-01

    Kissing molars are a very rare form of inclusion defined as molars included in the same quadrant, with occlusal surfaces contacting each other within a single dental follicle. We present four cases of this pathology: a 35 year-old male, referred to the Oral and Maxillofacial Surgery Department of the Hospital Virgen del Rocio in Seville, and three females of 24, 26, and 31 years, all of which had kissing molars that were treated by tooth extraction. We have found only 10 cases published in the medical literature in which this type of inclusion is briefly described, none of which elaborate on the surgical technique employed. In these cases, the indication for surgery is established when there is a history of recurring infections or cystic lesions associated with dental inclusions. The extraction of kissing molars requires an exhaustive comprehension of the anatomy of the region involved, sufficiently developed surgical abilities, and an extensive planning process. Impacted molar, kissing molar, surgical extraction.

  5. Displacement of maxillary third molar into the lateral pharyngeal space.

    PubMed

    Lee, Doksa; Ishii, Syoichiro; Yakushiji, Noboru

    2013-10-01

    Iatrogenic tooth displacement is a rare complication during extraction of impacted molars, but displacement of a maxillary third molar into the maxillary sinus, infratemporal fossa, buccal space, pterygomandibular space, and lateral pharyngeal space has been reported. Currently, 6 published reports describe third molar displacement into the lateral pharyngeal space, only 1 of which involved the loss of a maxillary third molar into this area, which occurred after an attempted self-extraction by the patient. There have been no reported cases of iatrogenic displacement of the maxillary third molar during an extraction procedure. This article describes the recovery, under general anesthesia, of a maxillary third molar from the lateral pharyngeal space after an iatrogenic displacement.

  6. Experimental and analytical separation of hydrodynamic, entropy and combustion noise in a gas turbine combustor

    NASA Technical Reports Server (NTRS)

    Muthukrishnan, M.; Strahle, W. C.; Neale, D. H.

    1977-01-01

    This paper deals with noise sources which are central to the problem of core engine noise in turbopropulsion systems. The sources dealt with are entropy noise and direct combustion noise, as well as a non-propagating psuedosound which is hydrodynamic noise. It is shown analytically and experimentally that a transition can occur from a combustion noise dominant situation to an entropy noise dominant case if the contraction of a terminating nozzle to the combustor is high enough. In the combustor tested, entropy noise is the dominant source for propagational noise if the combustor is choked at the exit. Analysis techniques include spectral, cross spectral, cross correlation, and ordinary and partial coherence analysis. Measurements include exterior and interior fluctuating and mean pressures and temperatures.

  7. [New surgical approach in apicoectomy of maxillary molars' palatal root].

    PubMed

    Hrusztics, Aminett; Bogdán, Sándor; Fellegi, Veronika; Szabó, György

    2003-06-01

    The term of apicectomy has been well-known for more than 200 years, nevertheless it is not performed frequently on molars. As a result of this a lot of molars became extracted. The aim of the authors was to present the new surgical technique which is described in detail. The radicular cyst localised on the palatal root of the first maxillary molar was operated on. Uneventful healing was obtained. This surgical technique is recommended in some special cases.

  8. Pathology related to third molars in the elderly persons.

    PubMed

    Ventä, Irja; Kylätie, Eeva; Hiltunen, Kaija

    2015-11-01

    The objective of this study was to clarify the discrepancy of pathology between earlier and recent studies related to third molars in the elderly persons. Evidence of third molars in the elders is limited. Earlier radiographic studies show rather few pathologic findings related to third molars. Recently, clinical studies have shown totally different numbers for pathology. Participants were drawn from the population-based Helsinki Aging Study. The study included panoramic radiographs of 293 persons (mean age 79 years, SD ± 3.9 years). We examined the prevalence of third molars and associated pathology and used the chi-squared test to perform the statistical analysis. Of the whole group of elderly persons, 19% had at least one third molar. The usual dental diseases, caries and periodontal pathology (80 and 33%, respectively), were common in the third molars. The surviving third molar most often appeared in the mandible (P < 0.01), in men (P < 0.05), in the mesioangular position (P < 0.05), and far from the mandibular canal (P < 0.001). Pathology was present in every third molar, although the proportion of serious pathology (i.e., cyst and tumor), accounted for only 2% of third molars. Although serious pathology related to third molars in the elders is uncommon, universal biofilm diseases (caries and periodontal pathology) widely affect third molars as well as all other teeth. Because all of the surviving third molars of the elders were diseased, it would be justifiable to extract these teeth at a younger age.

  9. Unusal canal configuration in maxillary and mandibular second molars

    PubMed Central

    Ragunathan, Ramachandran; Ebenezar, A. V. Rajesh; Mohan, Ajit George; Anand, S.

    2016-01-01

    This clinical article describes three different case reports of maxillary and mandibular second molars with the unusual anatomy of single root with a single canal and their endodontic management. An unusual case of bilateralism is observed in the first two cases in the form of single-rooted second mandibular molars in both the quadrant of the same patient. The presence of maxillary second molar with single root and single canal in the third case is unusual. PMID:27829778

  10. Increasing entropy for colloidal stabilization

    PubMed Central

    Mo, Songping; Shao, Xuefeng; Chen, Ying; Cheng, Zhengdong

    2016-01-01

    Stability is of paramount importance in colloidal applications. Attraction between colloidal particles is believed to lead to particle aggregation and phase separation; hence, stability improvement can be achieved through either increasing repulsion or reducing attraction by modifying the fluid medium or by using additives. Two traditional mechanisms for colloidal stability are electrostatic stabilization and steric stabilization. However, stability improvement by mixing attractive and unstable particles has rarely been considered. Here, we emphasize the function of mixing entropy in colloidal stabilization. Dispersion stability improvement is demonstrated by mixing suspensions of attractive nanosized titania spheres and platelets. A three-dimensional phase diagram is proposed to illustrate the collaborative effects of particle mixing and particle attraction on colloidal stability. This discovery provides a novel method for enhancing colloidal stability and opens a novel opportunity for engineering applications. PMID:27872473

  11. Entropy concepts in classical electrodynamics

    NASA Astrophysics Data System (ADS)

    Cole, Daniel C.

    2002-11-01

    Aspects of entropy and related thermodynamic analyses are discussed here that have been deduced in recent years in the area of classical electrodynamics. A motivating factor for most of this work has been an attempted theory of nature often called, "stochastic electrodynamics" (SED). This theory involves classical electrodynamics (Maxwell's equations plus the relativistic version of Newton's second law of motion for particles), but with the consideration that motion and fluctuations should not necessarily be assumed to reduce to zero at temperature T = 0. Both fairly subtle and rather blatant assumptions were often imposed in early thermodynamic analyses of electrodynamic systems that prevented the analyses from being sufficiently general to account for these "zero-point" properties, which hindered classical physics from being able to better account for quantum mechanical phenomena observed in nature. In turn, such thermodynamic considerations have helped motivate many of the key ideas of SED.

  12. Increasing entropy for colloidal stabilization

    NASA Astrophysics Data System (ADS)

    Mo, Songping; Shao, Xuefeng; Chen, Ying; Cheng, Zhengdong

    2016-11-01

    Stability is of paramount importance in colloidal applications. Attraction between colloidal particles is believed to lead to particle aggregation and phase separation; hence, stability improvement can be achieved through either increasing repulsion or reducing attraction by modifying the fluid medium or by using additives. Two traditional mechanisms for colloidal stability are electrostatic stabilization and steric stabilization. However, stability improvement by mixing attractive and unstable particles has rarely been considered. Here, we emphasize the function of mixing entropy in colloidal stabilization. Dispersion stability improvement is demonstrated by mixing suspensions of attractive nanosized titania spheres and platelets. A three-dimensional phase diagram is proposed to illustrate the collaborative effects of particle mixing and particle attraction on colloidal stability. This discovery provides a novel method for enhancing colloidal stability and opens a novel opportunity for engineering applications.

  13. Area terms in entanglement entropy

    NASA Astrophysics Data System (ADS)

    Casini, Horacio; Mazzitelli, F. D.; Testé, Eduardo

    2015-05-01

    We discuss area terms in entanglement entropy and show that a recent formula by Rosenhaus and Smolkin is equivalent to the term involving a correlator of traces of the stress tensor in the Adler-Zee formula for the renormalization of the Newton constant. We elaborate on how to fix the ambiguities in these formulas: Improving terms for the stress tensor of free fields, boundary terms in the modular Hamiltonian, and contact terms in the Euclidean correlation functions. We make computations for free fields and show how to apply these calculations to understand some results for interacting theories which have been studied in the literature. We also discuss an application to the F-theorem.

  14. Urban Transfer Entropy across Scales

    PubMed Central

    Murcio, Roberto

    2015-01-01

    The morphology of urban agglomeration is studied here in the context of information exchange between different spatio-temporal scales. Urban migration to and from cities is characterised as non-random and following non-random pathways. Cities are multidimensional non-linear phenomena, so understanding the relationships and connectivity between scales is important in determining how the interplay of local/regional urban policies may affect the distribution of urban settlements. In order to quantify these relationships, we follow an information theoretic approach using the concept of Transfer Entropy. Our analysis is based on a stochastic urban fractal model, which mimics urban growing settlements and migration waves. The results indicate how different policies could affect urban morphology in terms of the information generated across geographical scales. PMID:26207628

  15. Entropy changes in brain function.

    PubMed

    Rosso, Osvaldo A

    2007-04-01

    The traditional way of analyzing brain electrical activity, on the basis of electroencephalography (EEG) records, relies mainly on visual inspection and years of training. Although it is quite useful, of course, one has to acknowledge its subjective nature that hardly allows for a systematic protocol. In the present work quantifiers based on information theory and wavelet transform are reviewed. The "relative wavelet energy" provides information about the relative energy associated with different frequency bands present in the EEG and their corresponding degree of importance. The "normalized total wavelet entropy" carries information about the degree of order-disorder associated with a multi-frequency signal response. Their application in the analysis and quantification of short duration EEG signals (event-related potentials) and epileptic EEG records are summarized.

  16. UK National Third Molar project: the initial report.

    PubMed

    Worrall, S F; Riden, K; Haskell, R; Corrigan, A M

    1998-02-01

    The National Third Molar (NTM) project was set up to assess current clinical practice in the UK concerning the management of third molar teeth. Patients were recruited from both hospital and general dental practice. During the one month study period 9248 patients with 26,577 third molars were recruited. In this report we present the findings in the 8298 patients with 25,001 third molars who were referred to hospital for assessment. Over half of all patients referred for assessment had either no extractions or a single third molar extracted. Less than a quarter of all patients referred underwent removal of all four third molars. Twenty per cent of all third molars assessed were not extracted. Of all lower third molars listed for extraction, 9574 (78%) were associated with symptoms or disease. Pericoronitis was the commonest indication for extraction and was cited in 39.5% of all extractions. Almost 70% of third molar extractions were done under general anaesthesia while less than a quarter were performed under local anaesthesia alone.

  17. How multiplicity determines entropy and the derivation of the maximum entropy principle for complex systems.

    PubMed

    Hanel, Rudolf; Thurner, Stefan; Gell-Mann, Murray

    2014-05-13

    The maximum entropy principle (MEP) is a method for obtaining the most likely distribution functions of observables from statistical systems by maximizing entropy under constraints. The MEP has found hundreds of applications in ergodic and Markovian systems in statistical mechanics, information theory, and statistics. For several decades there has been an ongoing controversy over whether the notion of the maximum entropy principle can be extended in a meaningful way to nonextensive, nonergodic, and complex statistical systems and processes. In this paper we start by reviewing how Boltzmann-Gibbs-Shannon entropy is related to multiplicities of independent random processes. We then show how the relaxation of independence naturally leads to the most general entropies that are compatible with the first three Shannon-Khinchin axioms, the (c,d)-entropies. We demonstrate that the MEP is a perfectly consistent concept for nonergodic and complex statistical systems if their relative entropy can be factored into a generalized multiplicity and a constraint term. The problem of finding such a factorization reduces to finding an appropriate representation of relative entropy in a linear basis. In a particular example we show that path-dependent random processes with memory naturally require specific generalized entropies. The example is to our knowledge the first exact derivation of a generalized entropy from the microscopic properties of a path-dependent random process.

  18. How multiplicity determines entropy and the derivation of the maximum entropy principle for complex systems

    PubMed Central

    Hanel, Rudolf; Thurner, Stefan; Gell-Mann, Murray

    2014-01-01

    The maximum entropy principle (MEP) is a method for obtaining the most likely distribution functions of observables from statistical systems by maximizing entropy under constraints. The MEP has found hundreds of applications in ergodic and Markovian systems in statistical mechanics, information theory, and statistics. For several decades there has been an ongoing controversy over whether the notion of the maximum entropy principle can be extended in a meaningful way to nonextensive, nonergodic, and complex statistical systems and processes. In this paper we start by reviewing how Boltzmann–Gibbs–Shannon entropy is related to multiplicities of independent random processes. We then show how the relaxation of independence naturally leads to the most general entropies that are compatible with the first three Shannon–Khinchin axioms, the -entropies. We demonstrate that the MEP is a perfectly consistent concept for nonergodic and complex statistical systems if their relative entropy can be factored into a generalized multiplicity and a constraint term. The problem of finding such a factorization reduces to finding an appropriate representation of relative entropy in a linear basis. In a particular example we show that path-dependent random processes with memory naturally require specific generalized entropies. The example is to our knowledge the first exact derivation of a generalized entropy from the microscopic properties of a path-dependent random process. PMID:24782541

  19. Amoxicillin may cause molar incisor hypomineralization.

    PubMed

    Laisi, S; Ess, A; Sahlberg, C; Arvio, P; Lukinmaa, P-L; Alaluusua, S

    2009-02-01

    The etiology of molar incisor hypomineralization (MIH) is unclear. Our hypothesis was that certain antibiotics cause MIH. We examined 141 schoolchildren for MIH and, from their medical files, recorded the use of antibiotics under the age of 4 yrs. MIH was found in 16.3% of children. MIH was more common among those children who had taken, during the first year of life, amoxicillin (OR=2.06; 95% CI, 1.01-4.17) or the rarely prescribed erythromycin (OR=4.14; 95% CI, 1.05-16.4), compared with children who had not received treatment. Mouse E18 teeth were cultured for 10 days with/without amoxicillin at concentrations of 100 microg/mL-4 mg/mL. Amoxicillin increased enamel but not dentin thickness. An altered pattern of amelogenesis may have interfered with mineralization. We conclude that the early use of amoxicillin is among the causative factors of MIH.

  20. Molar absorptivity and the blank correction factor.

    PubMed

    Kroll, M H; Elin, R J

    1985-03-01

    In photometry, where both the product formed and one or several reactants absorb light at the same wavelength, the absorbance of the "blank" of the sample at the end of the reaction may be less than that measured at the beginning of the reaction, because of consumption of reactant(s). The blank correction factor for the determined result with one light-absorbing reagent is epsilon P / (epsilon P - epsilon R), where epsilon R and epsilon P are the molar absorptivities of the reagent and the product, respectively. We derived a factor for the case when more than one reagent absorbs light at the same wavelength as the measured product. This factor is independent of the concentration of reagent(s) and can correct the determined result or absorbance for the consumption of light-absorbing reagent(s) during the reaction.

  1. On entropy, financial markets and minority games

    NASA Astrophysics Data System (ADS)

    Zapart, Christopher A.

    2009-04-01

    The paper builds upon an earlier statistical analysis of financial time series with Shannon information entropy, published in [L. Molgedey, W. Ebeling, Local order, entropy and predictability of financial time series, European Physical Journal B-Condensed Matter and Complex Systems 15/4 (2000) 733-737]. A novel generic procedure is proposed for making multistep-ahead predictions of time series by building a statistical model of entropy. The approach is first demonstrated on the chaotic Mackey-Glass time series and later applied to Japanese Yen/US dollar intraday currency data. The paper also reinterprets Minority Games [E. Moro, The minority game: An introductory guide, Advances in Condensed Matter and Statistical Physics (2004)] within the context of physical entropy, and uses models derived from minority game theory as a tool for measuring the entropy of a model in response to time series. This entropy conditional upon a model is subsequently used in place of information-theoretic entropy in the proposed multistep prediction algorithm.

  2. On variational expressions for quantum relative entropies

    NASA Astrophysics Data System (ADS)

    Berta, Mario; Fawzi, Omar; Tomamichel, Marco

    2017-09-01

    Distance measures between quantum states like the trace distance and the fidelity can naturally be defined by optimizing a classical distance measure over all measurement statistics that can be obtained from the respective quantum states. In contrast, Petz showed that the measured relative entropy, defined as a maximization of the Kullback-Leibler divergence over projective measurement statistics, is strictly smaller than Umegaki's quantum relative entropy whenever the states do not commute. We extend this result in two ways. First, we show that Petz' conclusion remains true if we allow general positive operator-valued measures. Second, we extend the result to Rényi relative entropies and show that for non-commuting states the sandwiched Rényi relative entropy is strictly larger than the measured Rényi relative entropy for α \\in (1/2, ∞) and strictly smaller for α \\in [0,1/2) . The latter statement provides counterexamples for the data processing inequality of the sandwiched Rényi relative entropy for α < 1/2 . Our main tool is a new variational expression for the measured Rényi relative entropy, which we further exploit to show that certain lower bounds on quantum conditional mutual information are superadditive.

  3. Particle entropy and depairing in hot nuclei

    NASA Astrophysics Data System (ADS)

    Saranya, J. Dhivya; Boomadevi, N.; Rajasekaran, T. R.

    2016-11-01

    The nuclear level densities and single particle entropies are predicted for nuclei in the mass region 50 < A < 74 within a framework of statistical theory of hot nuclei method. In this method, particle-number and energy conservation as well as nuclear pairing correlations are included in the partition function of grand canonical ensemble. The suppression of pairing correlations is distinctly noticed in temperature dependence of entropies between the critical temperatures TC ≈ 0.7 MeV and TC ≈ 1.0 MeV for 50,51V, 61,62Ni and 73,74Ge isotopes of the elements. These structural thermodynamic entropies are interpreted as a remarkable signature of the superfluid to normal phase transition connected to the vanishing of pairing gap. The calculated level densities are compared with recent experimental values. In addition, the single particle entropy of intermediate-mass nuclei is depicted as half of the entropy of mid-shell nuclei in the rare-earth region. As a consequence, the N = 28 shell closure of 51V carries low entropy at low excitation energy presents an interesting analogy to the Z = 28 shell closure of 61Ni. Merely, in the case of odd-even 73Ge has higher entropy than the even-even 74Ge nucleus.

  4. Second molar periodontal inflammatory disease after third molar removal in young adults.

    PubMed

    Dicus, Carolyn; Blakey, George H; Faulk-Eggleston, Jan; Hoverstad, Eric; Offenbacher, Steven; Phillips, Ceib; White, Raymond P

    2010-12-01

    To assess the prevalence of periodontal inflammatory disease on the distal side of second molars after third molar removal and the association between presurgical and surgical variables and postsurgical periodontal outcomes. Data before and after surgery from 2 studies approved by an institutional review board were used. In 1 study, 26 subjects had 4 asymptomatic third molars and in the other 49 subjects had at least 1 mandibular third molar with symptoms of pericoronitis. Full-mouth periodontal probing data, 6 sites per tooth, were obtained as a measurement of periodontal status before and after surgery. A probing depth (PD) ≥4 mm on either of the 2 possible probing sites on the distal side of any second molar (D2M) served as an indicator of periodontal inflammatory disease; periodontal health was defined as all D2M PD <4 mm. Cochran-Mantel-Haenszel row mean score tests compared the subjects' postsurgical periodontal status (all D2M PD <4 mm and at least 1 D2M PD ≥4 mm) with respect to age and time intervals, and the Fisher exact test was used to compare ethnicity, gender, and clinical data at surgery. The McNemar test was used to assess the discordance between subjects' pre- and postsurgical periodontal status. The level of significance was set at .05. Of the 75 subjects, 52% were women and 65% were white. The median age at surgery was 23.6 years (interquartile range, 20.9 to 26.6 years). At enrollment, 53 of 75 subjects (71%) had at least 1 D2M PD ≥4 mm. Subjects were significantly more likely to have an improved D2M periodontal status after surgery than a deteriorated status (P < .01). Fewer subjects, 17 of 75 (24%), had at least 1 D2M PD ≥4 mm after surgery. D2M PD ≥4 mm was more likely after surgery if presurgical D2M was PD ≥4 mm (P < .01). Gender, ethnicity, age, presurgical symptoms, and data estimating the extensiveness of surgery were not significantly associated with postsurgical D2M periodontal outcomes. After third molar removal

  5. Early prediction of mandibular third molar eruption/impaction using linear and angular measurements on digital panoramic radiography: A radiographic study

    PubMed Central

    Kaur, Rachninder; Kumar, Anand C.; Garg, Ranjana; Sharma, Sugandha; Rastogi, Trisha; Gupta, Vivek Vijay

    2016-01-01

    Background: The impaction rate is higher for the third molars than for any other tooth in modern human population. This study was conducted with the aim to evaluate the validity of linear and angular measurements on the digital panoramic radiograph as a reference for early prediction of mandibular third molar eruption/impaction. Materials and Methods: Digital panoramic radiographs of 200 subjects were selected based on their status of eruption of mandibular third molars; fully erupted (Group A), partially erupted (Group B), fully developed but not erupted (Group C) and partially developed groups (Group D). Each group comprised 50 subjects with 25 males and 25 females. Nine variables (linear measurements, angles, and ratios) were determined and measured bilaterally by two observers and values were compared between the study groups and genders. Results: The data thus obtained were analyzed for comparison among all the study groups. It was found that the difference in the mean values of lower eruption space (LES) measurements, α-angle (angle between long axis of the third molar and gonial-symphyseal plane) and β-angle (angle between long axis of mandibular second and third molars) were significant (P < 0.05). The mean values of mesiodistal width, LES-ramus, LES-Xi point and β-angle were found more in males than in females. No significant difference was observed between the sides. Conclusion: α- and β-angle together with LES measurements give the accurate information on early prediction of lower third molar eruption or impaction. PMID:27433048

  6. On the dissipation and dispersion of entropy waves in heat transferring channel flows

    NASA Astrophysics Data System (ADS)

    Fattahi, A.; Hosseinalipour, S. M.; Karimi, N.

    2017-08-01

    This paper investigates the hydrodynamic and heat transfer effects on the dissipation and dispersion of entropy waves in non-reactive flows. These waves, as advected density inhomogeneities downstream of unsteady flames, may decay partially or totally before reaching the exit nozzle, where they are converted into sound. Attenuation of entropy waves dominates the significance of the subsequent acoustic noise generation. Yet, the extent of this decay process is currently a matter of contention and the pertinent mechanisms are still largely unexplored. To resolve this issue, a numerical study is carried out by compressible large eddy simulation of the wave advection in a channel subject to convective and adiabatic thermal boundary conditions. The dispersion, dissipation, and spatial correlation of the wave are evaluated by post-processing of the numerical results. This includes application of the classical coherence function as well as development of nonlinear quantitative measures of wave dissipation and dispersion. The analyses reveal that the high frequency components of the entropy wave are always strongly damped. The survival of the low frequency components heavily depends on the turbulence intensity and thermal boundary conditions of the channel. In general, high turbulence intensities and particularly heat transfer intensify the decay and destruction of the spatial coherence of entropy waves. In some cases, they can even result in the complete annihilation of the wave. The current work can therefore resolve the controversies arising over the previous studies of entropy waves with different thermal boundary conditions.

  7. Boundary fluctuations and a reduction entropy

    NASA Astrophysics Data System (ADS)

    Herzog, Christopher; Huang, Kuo-Wei

    2017-01-01

    The boundary Weyl anomalies live on a codimension-1 boundary, ∂M . The entanglement entropy originates from infinite correlations on both sides of a codimension-2 surface, Σ . Motivated to have a further understanding of the boundary effects, we introduce a notion of reduction entropy, which, guided by thermodynamics, is a combination of the boundary effective action and the boundary stress tensor defined by allowing the metric on ∂M to fluctuate. We discuss how a reduction might be performed so that the reduction entropy reproduces the entanglement structure.

  8. Maximum entropy analysis of transport networks

    NASA Astrophysics Data System (ADS)

    Waldrip, Steven H.; Niven, Robert K.; Abel, Markus; Schlegel, Michael

    2017-06-01

    The maximum entropy method is used to derive an alternative gravity model for a transport network. The proposed method builds on previous methods which assign the discrete value of a maximum entropy distribution to equal the traffic flow rate. The proposed method however, uses a distribution to represent each flow rate. The proposed method is shown to be able to handle uncertainty in a more elegant way and give similar results to traditional methods. It is able to incorporate more of the observed data through the entropy function, prior distribution and integration limits potentially allowing better inferences to be made.

  9. A psychophysical theory of Shannon entropy.

    PubMed

    Takahashi, Taiki

    2013-01-01

    Connections between information theory and decision under uncertainty have been attracting attention in econophysics, neuroeconomics and quantum decision theory. This paper proposes a psychophysical theory of Shannon entropy based on a mathematical equivalence of delay and uncertainty in decision-making, and psychophysics of the perception of waiting time in probabilistic choices. Furthermore, it is shown that the well-known Shannon entropy is a special case of the general psychophysical entropy. Future directions in the application of the present theory to studies in econophysics and neuroeconomics are discussed.

  10. Wald entropy formula and loop quantum gravity

    NASA Astrophysics Data System (ADS)

    Bodendorfer, N.; Neiman, Y.

    2014-10-01

    We outline how the Wald entropy formula naturally arises in loop quantum gravity based on recently introduced dimension-independent connection variables. The key observation is that in a loop quantization of a generalized gravity theory, the analog of the area operator turns out to measure, morally speaking, the Wald entropy rather than the area. We discuss the explicit example of (higher-dimensional) Lanczos-Lovelock gravity and comment on recent work on finding the correct numerical prefactor of the entropy by comparing it to a semiclassical effective action.

  11. Entropy production for complex Langevin equations

    NASA Astrophysics Data System (ADS)

    Borlenghi, Simone; Iubini, Stefano; Lepri, Stefano; Fransson, Jonas

    2017-07-01

    We study irreversible processes for nonlinear oscillators networks described by complex-valued Langevin equations that account for coupling to different thermochemical baths. Dissipation is introduced via non-Hermitian terms in the Hamiltonian of the model. We apply the stochastic thermodynamics formalism to compute explicit expressions for the entropy production rates. We discuss in particular the nonequilibrium steady states of the network characterized by a constant production rate of entropy and flows of energy and particle currents. For two specific examples, a one-dimensional chain and a dimer, numerical calculations are presented. The role of asymmetric coupling among the oscillators on the entropy production is illustrated.

  12. Growth rate, population entropy, and perturbation theory.

    PubMed

    Demetrius, L

    1989-04-01

    This paper is concerned with the connection between two classes of population variables: measures of population growth rate--the Malthusian parameter, the net reproduction rate, the gross reproduction rate, and the mean life expectancy; and measures of demographic heterogeneity--population entropy. It is shown that the entropy functions predict the response of the growth rate parameters to perturbations in the age-specific fecundity and mortality schedule. These results are invoked to introduce the notion of environmental intensity. The intensity function, expressed in terms of the entropy parameters, is applied to give a comparative study of the effect of environmental factors on the dynamics of Swedish and French populations.

  13. Qualitative and quantitative assessment of relationship between mandibular third molar and angle fracture on North Indian population: A clinico-radiographic study.

    PubMed

    Yadav, Suresh; Tyagi, Shallu; Puri, Naveen; Kumar, Prince; Kumar, Puneet

    2013-04-01

    To assess the relationship between impacted mandibular third molar presence and the risk for mandibular angle fracture with the effect of various positions of mandibular third molar and the risk of mandibular angle fracture. In the North Indian territory, a total of 289 patients with mandibular angle fractures were studied and evaluated for the possible relationship with impacted third molar on the basis of clinical and panoramic radiographical findings. Results that confirmed the highest risk for mandibular angle fracture was associated with mesioangular angulations (45.42%) followed by vertical (26.34%), distoangular in sequence and least risk was found with bucco-version angulations (2.67%) according to Winter's classification. Additionally, the highest risk of mandibular angle fracture was reported with partially erupted third molar (47.75%), followed by erupted (23.53%) and unerupted third molar (19.38%). The risk for mandibular angle fracture is not only affected by status of eruption, angulations, position, number of roots present in third molar but also by the distance of mandibular third molar from inferior border of mandible and the percentage of remaining amount of bone at the mandibular angle region.

  14. Tree-shifts: the entropy of tree-shifts of finite type

    NASA Astrophysics Data System (ADS)

    Ban, Jung-Chao; Chang, Chih-Hung

    2017-07-01

    This paper studies the entropy of tree-shifts of finite type with and without boundary conditions. We demonstrate that computing the entropy of a tree-shift of finite type is equivalent to solving a system of nonlinear recurrence equations. Furthermore, the entropy of the binary Markov tree-shifts over two symbols is either 0 or \\ln 2 . Meanwhile, the realization of a class of reals including multinacci numbers is elaborated, which indicates that tree-shifts are capable of rich phenomena. By considering the influence of three different types of boundary conditions, say, the periodic, Dirichlet, and Neumann boundary conditions, the necessary and sufficient conditions for the coincidence of entropy with and without boundary conditions are addressed. This work is partially supported by the Ministry of Science and Technology, ROC (Contract No MOST 105-2115-M-259 -006 -MY2 and 105-2115-M-390 -001 -MY2). The first author is partially supported by National Center for Theoretical Sciences.

  15. Black hole entropy, topological entropy and the Baum-Connes conjecture in K-theory

    NASA Astrophysics Data System (ADS)

    Zois, Ioannis P.

    2002-03-01

    We shall try to show a relation between black hole (BH) entropy and topological entropy using the famous Baum-Connes conjecture for foliated manifolds which are particular examples of noncommutative spaces. Our argument is qualitative and it is based on the microscopic origin of the Beckenstein-Hawking area-entropy formula for BHs, provided by superstring theory, in the more general noncommutative geometric context of M-theory following the approach of Connes-Douglas-Schwarz.

  16. Modified correlation entropy estimation for a noisy chaotic time series.

    PubMed

    Jayawardena, A W; Xu, Pengcheng; Li, W K

    2010-06-01

    A method of estimating the Kolmogorov-Sinai (KS) entropy, herein referred to as the modified correlation entropy, is presented. The method can be applied to both noise-free and noisy chaotic time series. It has been applied to some clean and noisy data sets and the numerical results show that the modified correlation entropy is closer to the KS entropy of the nonlinear system calculated by the Lyapunov spectrum than the general correlation entropy. Moreover, the modified correlation entropy is more robust to noise than the correlation entropy.

  17. Mandibular First Molar with a Single Root and Single Canal

    PubMed Central

    Sooriaprakas, Chandrasekaran; Ballal, Suma; Velmurugan, Natanasabapathy

    2014-01-01

    Successful endodontic management of mandibular first molar with a single root and single canal is diagnosed with the aid of dental operating microscope and multiple angled radiographs. In addition all the mandibular molars and premolars were single rooted on either side. PMID:24715990

  18. Molar incisor hypomineralisation: clinical management of the young patient.

    PubMed

    Daly, Dympna; Waldron, J M

    2009-01-01

    Molar incisor hypomineralisation (MIH) is a common developmental condition resulting in enamel defects in first permanent molars and permanent incisors. It presents at eruption of these teeth. Early diagnosis is essential since rapid breakdown of tooth structure may occur, giving rise to acute symptoms and complicated treatment. The purpose of this article is to review MIH and illustrate its clinical management in young children.

  19. Toward the Unification of Molecular and Molar Analyses

    PubMed Central

    2013-01-01

    Three categories of behavior analysis may be called molecular, molar, and unified. Molecular analyses focus on how manual shaping segments moment-to-moment behaving into new, unified, hierarchically organized patterns. Manual shaping is largely atheoretical, qualitative, and practical. Molar analyses aggregate behaviors and then compute a numerical average for the aggregate. Typical molar analyses involve average rate of, or average time allocated to, the aggregated behaviors. Some molar analyses have no known relation to any behavior stream. Molar analyses are usually quantitative and often theoretical. Unified analyses combine automated shaping of moment-to-moment behaving and molar aggregates of the shaped patterns. Unified controlling relations suggest that molar controlling relations like matching confound shaping and strengthening effects of reinforcement. If a molecular analysis is about how reinforcement organizes individual behavior moment by moment, and a molar analysis is about how reinforcement encourages more or less of an activity aggregated over time, then a unified analysis handles both kinds of analyses. Only theories engendered by computer simulation appear to be able to unify all three categories of behavior analysis. PMID:28018041

  20. On statistical properties of Jizba-Arimitsu hybrid entropy

    NASA Astrophysics Data System (ADS)

    Çankaya, Mehmet Niyazi; Korbel, Jan

    2017-06-01

    Jizba-Arimitsu entropy (also called hybrid entropy) combines axiomatics of Rényi and Tsallis entropy. It has many common properties with them, on the other hand, some aspects as e.g., MaxEnt distributions, are different. In this paper, we discuss statistical properties of hybrid entropy. We define hybrid entropy for continuous distributions and its relation to discrete entropy. Additionally, definition of hybrid divergence and its connection to Fisher metric is also presented. Interestingly, Fisher metric connected to hybrid entropy differs from corresponding Fisher metrics of Rényi and Tsallis entropy. This motivates us to introduce average hybrid entropy, which can be understood as an average between Tsallis and Rényi entropy.