Truncation of lattice fractional quantum Hall Hamiltonians derived from conformal field theory

Conformal field theory has recently been applied to derive few-body Hamiltonians whose ground states are lattice versions of fractional quantum Hall states. The exact lattice models involve interactions over long distances, which is difficult to realize in experiments. It seems, however, that such long-range interactions should not be necessary, as the correlations decay exponentially in the bulk. This poses the question, whether the Hamiltonians can be truncated to contain only local interactions without changing the physics of the ground state. Previous studies have in a couple of cases with particularly much symmetry obtained such local Hamiltonians by keeping only a few local terms and numerically optimizing the coefficients. Here, we investigate a different strategy to construct truncated Hamiltonians, which does not rely on optimization, and which can be applied independent of the choice of lattice. We test the approach on two models with bosonic Laughlin-like ground states with filling factor $1/2$ and $1/4$, respectively. We first investigate how the coupling strengths in the exact Hamiltonians depend on distance, and then we study the truncated models. For the case of $1/2$ filling, we find that the truncated model with truncation radius $\sqrt{2}$ lattice constants on the square lattice and $1$ lattice constant on the triangular lattice has an approximate twofold ground state degeneracy on the torus, and the overlap per site between these states and the states constructed from conformal field theory is higher than $0.99$ for the lattices considered. For the model at $1/4$ filling, our results give some hints that a truncation radius of $\sqrt{5}$ on the square lattice and $\sqrt{7}$ on the triangular lattice might be enough, but the finite size effects are too large to judge whether the topology is, indeed, present in the thermodynamic limit.Comment: 8 Pages, 10 Figure

Empirical Relationship between Intra-Purine and Intra-Pyrimidine Differences in Conserved Gene Sequences

DNA sequences seen in the normal character-based representation appear to have a formidable mixing of the four nucleotides without any apparent order. Nucleotide frequencies and distributions in the sequences have been studied extensively, since the simple rule given by Chargaff almost a century ago that equates the total number of purines to the pyrimidines in a duplex DNA sequence. While it is difficult to trace any relationship between the bases from studies in the character representation of a DNA sequence, graphical representations may provide a clue. These novel representations of DNA sequences have been useful in providing an overview of base distribution and composition of the sequences and providing insights into many hidden structures. We report here our observation based on a graphical representation that the intra-purine and intra-pyrimidine differences in sequences of conserved genes generally follow a quadratic distribution relationship and show that this may have arisen from mutations in the sequences over evolutionary time scales. From this hitherto undescribed relationship for the gene sequences considered in this report we hypothesize that such relationships may be characteristic of these sequences and therefore could become a barrier to large scale sequence alterations that override such characteristics, perhaps through some monitoring process inbuilt in the DNA sequences. Such relationship also raises the possibility of intron sequences playing an important role in maintaining the characteristics and could be indicative of possible intron-late phenomena

Potensi Pembangkit Daya Termoelektrik Untuk Kendaraan Hibrid

Potency of Thermoelectric Generator for Hybrid Vehicle. Thermoelectric Generator (TEG) has been known aselectricity generation for many years. If the temperature difference occurred between two difference semi conductormaterials, the current will flow in the material and produced difference voltage. This principle is known as Seebeckeffect that is the opposite of Peltier effect Thermoelectric Cooling (TEC). This research was conducted to test thepotential of electric source from twelve peltier modules. Then, these thermoelectric generators were applied in hybridcar by using waste heat from the combustion engine. The experiment has been conducted with variations of peltiermodule arrangements (series and parallels) and heater as heat source for the thermoelectric generator, with variations ofheater voltage input (110V and 220V) applied. The experimental result showed that twelve of peltier modules arrangedin series and heater voltage of 220V generated power output of 8.11 Watts with average temperature difference of42.82°C. This result shows that TEG has a bright prospect as alternative electric source

Symmetries and novel universal properties of turbulent hydrodynamics in a symmetric binary fluid mixture

We elucidate the universal properties of the nonequilibrium steady states (NESS) in a driven symmetric binary fluid mixture, an example of active advection, in its miscible phase. We use the symmetries of the equations of motion to establish the appropriate form of the structure functions which characterise the statistical properties of the NESS of a driven symmetric binary fluid mixture. We elucidate the universal properties described by the scaling exponents and the amplitude ratios. Our results suggest that these exponents and amplitude ratios vary continuously with the degree of crosscorrelations between the velocity and the gradient of the concentration fields. Furthermore, we demonstrate, in agreement with Celani et al, Phys. Rev. Lett., 89, 234502 (2002, that the conventional structure functions as used in passive scalar turbulence studies exhibit only simple scaling in the problem of symmetric binary fluid mixture even in the weak concentration limit. We also discuss possible experimental verifications of our results.Comment: To appear in JSTAT (letters) (2005

Ultraviolet Imaging Polarimetry of the Large Magellanic Cloud. II. Models

Motivated by new sounding-rocket wide-field polarimetric images of the Large Magellanic Cloud, we have used a three-dimensional Monte Carlo radiation transfer code to investigate the escape of near-ultraviolet photons from young stellar associations embedded within a disk of dusty material (i.e. a galaxy). As photons propagate through the disk, they may be scattered or absorbed by dust. Scattered photons are polarized and tracked until they escape to be observed; absorbed photons heat the dust, which radiates isotropically in the far-infrared, where the galaxy is optically thin. The code produces four output images: near- UV and far-IR flux, and near-UV images in the linear Stokes parameters Q and U. From these images we construct simulated UV polarization maps of the LMC. We use these maps to place constraints on the star + dust geometry of the LMC and the optical properties of its dust grains. By tuning the model input parameters to produce maps that match the observed polarization maps, we derive information about the inclination of the LMC disk to the plane of the sky, and about the scattering phase function g. We compute a grid of models with i = 28 deg., 36 deg., and 45 deg., and g = 0.64, 0.70, 0.77, 0.83, and 0.90. The model which best reproduces the observed polarization maps has i = 36 +2/-5 degrees and g ~0.7. Because of the low signal-to-noise in the data, we cannot place firm constraints on the value of g. The highly inclined models do not match the observed centro-symmetric polarization patterns around bright OB associations, or the distribution of polarization values. Our models approximately reproduce the observed ultraviolet photopolarimetry of the western side of the LMC; however, the output images depend on many input parameters and are nonunique.Comment: Accepted to AJ. 20 pages, 7 figure

Procrastination among basic science undergraduate medical students in a Caribbean medical school

Abstract Purpose: The study was conducted to study procrastination behavior among basic science undergraduate medical students using the previously validated procrastination assessment scale students (PASS). Frequency of and reasons for procrastination were compared among different subgroups of respondents. Methods: The study was conducted during the first two weeks of February 2017 using PASS. Gender, nationality and semester of study of the respondents were noted. PASS explores areas of and frequency of procrastination, reasons for procrastination and interest in changing the behavior. The frequency of procrastination, fear of failure, risk aversiveness, laziness and rebellion against control scores were compared among different subgroups using appropriate statistical tests. Results: A total of 107 students (84.9%) participated in the study. The mean frequency of procrastination score was 32.9 (maximum score 60). The score was significantly correlated with the respondents' gender. With regard to the percentage of students who nearly always or always procrastinated on a task, the percentages with regard to completing assignments, studying for exams, completing reading assignments, academic administrative tasks, attendance tasks and school activities in general were 25.2, 19.7, 25.2, 19.6, 18.7 and 17.7. The mean score for 'fear of failure' and 'aversiveness of task' as described by Solomon and Rothblum was 2.29 and 2.83. The mean scores for fear of failure, risk taking, and laziness were 26.17, 13.76 and 14.32. The median rebellion against control score was 6. Risk taking score was higher among respondents of other nationalities compared to Americans. Conclusions: Procrastination was regarded as a greater problem with regard to studying for exams and completing reading assignments and preparing for problem-based learning sessions. Only 42% of students were interested in attending a program to overcome procrastination. Similar studies among students during the clinical years are required. A study correlating self-reported procrastination with behavior can be carried out. Procrastination can als