Correlations around an interface

We compute one-loop correlation functions for the fluctuations of an interface using a field theory model. We obtain them from Feynman diagrams drawn with a propagator which is the inverse of the Hamiltonian of a Poschl-Teller problem. We derive an expression for the propagator in terms of elementary functions, show that it corresponds to the usual spectral sum, and use it to calculate quantities such as the surface tension and interface profile in two and three spatial dimensions. The three-dimensional quantities are rederived in a simple, unified manner, whereas those in two dimensions extend the existing literature, and are applicable to thin films. In addition, we compute the one-loop self-energy, which may be extracted from experiment, or from Monte Carlo simulations. Our results may be applied in various scenarios, which include fluctuations around topological defects in cosmology, supersymmetric domain walls, Z(N) bubbles in QCD, domain walls in magnetic systems, interfaces separating Bose-Einstein condensates, and interfaces in binary liquid mixtures.Comment: RevTeX, 13 pages, 6 figure

Delay times and reflection in chaotic cavities with absorption

Absorption yields an additional exponential decay in open quantum systems which can be described by shifting the (scattering) energy E along the imaginary axis, E+i\hbar/2\tau_{a}. Using the random matrix approach, we calculate analytically the distribution of proper delay times (eigenvalues of the time-delay matrix) in chaotic systems with broken time-reversal symmetry that is valid for an arbitrary number of generally nonequivalent channels and an arbitrary absorption rate 1/\tau_{a}. The relation between the average delay time and the ``norm-leakage'' decay function is found. Fluctuations above the average at large values of delay times are strongly suppressed by absorption. The relation of the time-delay matrix to the reflection matrix S^{\dagger}S is established at arbitrary absorption that gives us the distribution of reflection eigenvalues. The particular case of single-channel scattering is explicitly considered in detail.Comment: 5 pages, 3 figures; final version to appear in PRE (relation to reflection extended, new material with Fig.3 added, experiment cond-mat/0305090 discussed

Polymorphism In Lep And Lepr May Modify Leptin Levels And Represent Risk Factors For Thyroid Cancer

Purpose. To understand the role of polymorphisms in the LEP (rs7799039 and rs2167270) and LEPR (rs1137101 and rs1137100) genes in DTC susceptibility and their effect on leptin levels. Methods. We studied 153 patients with DTC and 234 controls through TaqMan SNP Genotyping and ELISA, comparing these data to the clinicopathological data of patients with DTC. Results. Patients with AA genotype of rs7799039 had higher levels of serum leptin (9.22 ± 0.98 ng/mL) than those with AG genotype (10.07 ± 0.60 ng/mL; P = 0.005). Individuals with AG genotype of rs2167270 also produced higher serum leptin levels (10.05 ± 0.59 ng/mL) than the subjects with GG genotype (9.52 ± 0.79 ng/mL; P A) polymorphism and disease susceptibility and cardiovascular disease in patients with rheumatoid arthritis (2011) Clinical and Experimental Rheumatology, 29 (2), pp. 293-298Jiang, Y., Wilk, J.B., Borecki, I., Common variants in the 5' region of the leptin gene are associated with bodymass index in men fromthe National Heart, Lung, and Blood Institute Family Heart Study (2004) The American Journal of Human Genetics, 75 (2), pp. 220-230He, J., Xi, B., Ruiter, R., Association of LEP G2548A and LEPR Q223R polymorphisms with cancer susceptibility: Evidence froma meta-analysis (2013) PLoS ONE, 8 (10)Furusawa, T., Naka, I., Yamauchi, T., The Q223R polymorphism in LEPR is associated with obesity in Pacific Islanders (2010) Human Genetics, 127 (3), pp. 287-294Saukko, M., Kesäniemi, Y.A., Ukkola, O., Leptin receptor Lys109Arg and Gln223Arg polymorphisms are associated with early atherosclerosis (2010) Metabolic Syndrome and Related Disorders, 8 (5), pp. 425-430Lucas, A., Granada, M.L., Olaizola, I., Leptin and thyrotropin relationship is modulated by smoking status in euthyroid subjects (2013) Thyroid, 23 (8), pp. 964-970Duntas, L.H., Biondi, B., The interconnections between obesity, thyroid function, and autoimmunity: Themultifold role of leptin (2013) Thyroid, 23 (6), pp. 646-653Marzullo, P., Minocci, A., Tagliaferri, M.A., Investigations of thyroid hormones and antibodies in obesity: Leptin levels are associated with thyroid autoimmunity independent of bioanthropometric, hormonal, and weight-related determinants (2010) Journal of Clinical Endocrinology and Metabolism, 95 (8), pp. 3965-3972Guzel, S., Seven, A., Guzel, E.C., Buyuk, B., Celebi, A., Aydemir, B., Visfatin, leptin, and TNF-α: Interrelated adipokines in insulin-resistant clinical and subclinical hypothyroidism (2013) Endocrine Research, 38 (3), pp. 184-194Mammès, O., Betoulle, D., Aubert, R., Herbeth, B., Siest, G., Fumeron, F., Association of the G-2548A polymorphism in the 5' region of the LEP gene with overweight (2000) Annals of Human Genetics, 64 (5), pp. 391-394Portoles, O., Sorli, J.V., Frances, F., Effect of genetic variation in the leptin gene promoter and the leptin receptor gene on obesity risk in a population-based case-control study in Spain (2006) European Journal of Epidemiology, 21 (8), pp. 605-612Liu, C., Liu, L., Polymorphisms in three obesity-related genes (LEP, LEPR, and PON1) and breast cancer risk: A metaanalysis (2011) Tumour Biology, 32 (6), pp. 1233-1240Hoffsted, J., Eriksson, P., Mottagui-Tabar, S., Arner, P., A polymorphism in the leptin promoter region (-2548 G/A) influences gene expression and adipose tissue secretion of leptin (2002) Hormone and Metabolic Research, 34 (7), pp. 355-359Murugesan, D., Arunachalam, T., Ramamurthy, V., Subramanian, S., Association of polymorphisms in leptin receptor gene with obesity and type 2 diabetes in the local population of Coimbatore (2010) Indian Journal of Human Genetics, 16 (2), pp. 72-77Quinton, N.D., Lee, A.J., Ross, R.J.M., Eastell, R., Blakemore, A.I.F., A single nucleotide polymorphism (SNP) in the leptin receptor is associated with BMI, fatmass and leptin levels in postmenopausal Caucasian women (2001) Human Genetics, 108 (3), pp. 233-236Mattevi, V.S., Zembrzuski, V.M., Hutz, M.H., Association analysis of genes involved in the leptin-signaling pathway with obesity in Brazil (2002) International Journal of Obesity, 26 (9), pp. 1179-1185Yiannakouris, N., Yannakoulia, M., Melistas, L., Chan, J.L., Klimis-Zacas, D., Mantzoros, C.S., TheQ223Rpolymorphism of the leptin receptor gene is significantly associated with obesity and predicts a small percentage of bodyweight and body composition variability (2001) Journal of Clinical Endocrinology and Metabolism, 86 (9), pp. 4434-4439Stefan, N., Vozarova, B., Del Parigi, A., The Gln223Arg polymorphism of the leptin receptor in Pima Indians: Influence on energy expenditure, physical activity and lipid metabolism (2002) International Journal of Obesity, 26 (12), pp. 1629-1632Chiu, K.C., Chu, A., Chuang, L.-M., Saad, M.F., Association of leptin receptor polymorphism with insulin resistance (2004) European Journal of Endocrinology, 150 (5), pp. 725-729Chu, A., Chuang, L.M., Saad, M., Chiu, K., Association of the Q223R polymorphism of the leptin receptor gene with insulin resistance and metabolic syndrome (2003) Diabetes, 52, p. A510Pimentel Duarte, S.F., Francischetti, E.A., Genelhu-Abreu, V., P. Q223R leptin receptor polymorphism associated with obesity in Brazilianmultiethnic subjects (2006) The American Journal of Human Biology, 18 (4), pp. 448-453Wauters, M., Mertens, I., Chagnon, M., Polymorphisms in the leptin receptor gene, body composition and fat distribution in overweight and obese women (2001) International Journal of Obesity, 25 (5), pp. 714-720Ogawa, T., Hirose, H., Yamamoto, Y., Relationships between serum soluble leptin receptor level and serum leptin and adiponectin levels, insulin resistance index, lipid profile, and leptin receptor gene polymorphisms in the Japanese population (2004) Metabolism: Clinical and Experimental, 53 (7), pp. 879-885Fairbrother, U.L., Tankó, L.B., Walley, A.J., Christiansen, C., Froguel, P., Blakemore, A.I.F., Leptin receptor genotype at Gln223Arg is associated with body composition, BMD, and vertebral fracture in postmenopausal Danish women (2007) Journal of Bone and Mineral Research, 22 (4), pp. 544-550Salopuro, T., Pulkkinen, L., Lindström, J., Genetic variation in leptin receptor gene is associated with type 2 diabetes and body weight: The Finnish Diabetes Prevention Study (2005) International Journal of Obesity, 29 (10), pp. 1245-1251Wauters, M., Mertens, I., Rankinen, T., Chagnon, M., Bouchardt, C., Van Gaal, L., Leptin receptor gene polymorphisms are associated with insulin in obese women with impaired glucose tolerance (2001) Journal of Clinical Endocrinology and Metabolism, 86 (7), pp. 3227-3232Park, K.S., Shin, H.D., Park, B.L., Polymorphisms in the leptin receptor (LEPR)-putative association with obesity and T2DM (2006) Journal of Human Genetics, 51 (2), pp. 85-91Han, C.-Z., Du, L.-L., Jing, J.-X., Associations among lipids, leptin, and leptin receptor geneGin223Arg polymorphisms and breast cancer in China (2008) Biological Trace Element Research, 126 (1-3), pp. 38-48Okobia, M.N., Bunker, C.H., Garte, S.J., Leptin receptor Gln223Arg polymorphism and breast cancer risk in Nigerian women: A case control study (2008) BMC Cancer, 8He, B.-S., Pan, Y.-Q., Zhang, Y., Xu, Y.-Q., Wang, S.-K., Effect of LEPR Gln223Arg polymorphism on breast cancer risk in different ethnic populations: A meta-analysis (2012) Molecular Biology Reports, 39 (3), pp. 3117-3122Lin, D.W., Fitz Gerald, L.M., Fu, R., Genetic variants in the LEPR, CRY1, RNASEL, IL4, and ARVCF genes are prognostic markers of prostate cancer-specific mortality (2011) Cancer Epidemiology, Biomarkers & Prevention, 20 (9), pp. 1928-1936Li, Y.L., Geng, J.L., Wang, Y., The role of leptin receptor gene polymorphisms in determining the susceptibility and prognosis of NSCLC in Chinese patients (2012) Journal of Cancer Research and Clinical Oncology, 138 (2), pp. 311-316Wazir, U., Al Sarakbi, W., Jiang, W.G., Mokbel, K., Evidence of an autocrine role for leptin and leptin receptor in human breast cancer (2012) CancerGenomics and Proteomics, 9 (6), pp. 383-388Li, L., Lee, K.J., Choi, B.C., Baek, K.H., Relationshipbetween leptin receptor and polycystic ovary syndrome (2013) Gene, 527 (1), pp. 71-74Friedlander, Y., Li, G., Fornage, M., Candidate molecular pathway genes related to appetite regulatory neural network, adipocyte homeostasis and obesity: Results from the CARDIA Study (2010) Annals of Human Genetics, 74 (5), pp. 387-39

Electron transmission and phase time in semiconductor superlattices

We discuss the time spent by an electron propagating through a finite periodic system such as a semiconductor superlattice. The relation between dwell-time and phase-time is outlined. The envelopes of phase-time at maximum and minimum transmission are derived, and it is shown that the peaks and valleys of phase-time can be well described by parameters fitted at the extrema. For a many-period system this covers most of the allowed band. Comparison is made to direct numerical solutions of the time-dependent Schr\"odinger equation by Veenstra et al. [cond-mat/0411118] who compared systems with and without addition of an anti-reflection coating (ARC). With an ARC, the time delay is consistent with propagation at the Bloch velocity of the periodic system, which significantly reduces the time delay, in addition to increasing the transmissivity.Comment: 8 pages, 10 figures, based on a talk at Theory-Canada 3 in Edmonton AB, June 200

Dwell-time distributions in quantum mechanics

Some fundamental and formal aspects of the quantum dwell time are reviewed, examples for free motion and scattering off a potential barrier are provided, as well as extensions of the concept. We also examine the connection between the dwell time of a quantum particle in a region of space and flux-flux correlations at the boundaries, as well as operational approaches and approximations to measure the flux-flux correlation function and thus the second moment of the dwell time, which is shown to be characteristically quantum, and larger than the corresponding classical moment even for freely moving particles.Comment: To appear in "Time in Quantum Mechanics, Vol. 2", Springer 2009, ed. by J. G. Muga, A. Ruschhaupt and A. del Camp