Gravitational anomalies in a dispersive approach

The gravitational anomalies in two dimensions, specifically the Einstein anomaly and the Weyl anomaly, are fully determined by means of dispersion relations. In this approach the anomalies originate from the peculiar infrared feature of the imaginary part of the relevant formfactor which approaches a $\delta$-function singularity at zero momentum squared when $m \to 0$.Comment: 10 page

Proses Hidrokimia pada Air Dolina Kars Gunungsewu di Kabupaten Gunungkidul, Yogyakarta

Salah satu permasalahan di daerah kars yang menarik untuk dikaji adalah masalah hidrokimia, khususnya pada subbentang alam eksokars yang berupa dolina.Penelitian ini bertujuan untuk mengetahui fenomena proses hidrokimia pada air dolina yang terjadi pada dua sub sistem hidrogeologi Panggang dan Wonosari-Baron, Kabupaten Gunungkidul. Metode yang dilakukan adalah survey hidrogeologi dilengkapi dengan uji sifat fisik/kimia air di laboratorium. Analisis hidrokimia dilakukan menggunakan diagram Piper dan grafik hubungan antar ion. Fasies hidrokimia pada musim kemarau pada umumnya berkembang sebagai fasies Ca,Na-bikarbonat, sedangkan pada musim hujan, air dolina didominasi oleh fasies Ca-bikarbonat. Hidrokimia air dolina sangat dipengaruhi oleh proses pelapukan disolusi batugamping sebagai proses utama, selain adanya pengayaan pada musim kemarau melalui proses evaporasi. Pada musim hujan, presipitasi ikut berperan penting dalam mempengaruhi hidrokimia air dolina melalui proses dilusi. Adapun proses antropogenik hanya menunjukkan intensitas yang kecil

Symmetries of generalized soliton models and submodels on target space S2S^2

Some physically relevant non-linear models with solitons, which have target space $S^2$, are known to have submodels with infinitly many conservation laws defined by the eikonal equation. Here we calculate all the symmetries of these models and their submodels by the prolongation method. We find that for some models, like the Baby Skyrme model, the submodels have additional symmetries, whereas for others, like the Faddeev--Niemi model, they do not.Comment: 18 pages, one Latex fil

Synthesis of toxyloxanthone B

A synthesis of the naturally occurring xanthone toxyloxanthone B is described, in which the key step is the regioselective addition of a methyl salicylate to a substituted benzyne followed by cyclization of the intermediate aryl anion to form the xanthone, the regiochemistry of the aryne addition being confirmed by X-ray crystallography. Subsequent introduction of the pyran ring by [3,3]-rearrangement and deprotection completed the synthesi

Integrability and Conformal Symmetry in the BCS model

The exactly solvable BCS Hamiltonian of superconductivity is considered from several viewpoints: Richardson's ansatz, conformal field theory, integrable inhomogenous vertex models and Chern-Simons theory.Comment: Latex with macros included, 12 pages, Proceedings of the NATO Advanced Research Workshop on Statistical Field Theories, Como 18-23 June 2001. Editors: Andrea Cappelli and Giuseppe Mussardo. to be published by Kluwer, Academic Publishers. Corrected some typos and further acknowledgment

Conductance Peak Height Correlations for a Coulomb-Blockaded Quantum Dot in a Weak Magnetic Field

We consider statistical correlations between the heights of conductance peaks corresponding to two different levels in a Coulomb-blockaded quantum dot. Correlations exist for two peaks at the same magnetic field if the field does not fully break time-reversal symmetry as well as for peaks at different values of a magnetic field that fully breaks time-reversal symmetry. Our results are also relevant to Coulomb-blockade conductance peak height statistics in the presence of weak spin-orbit coupling in a chaotic quantum dot.Comment: 5 pages, 3 figures, REVTeX 4, accepted for publication in Phys. Rev.

Symplectic geometry of entanglement

We present a description of entanglement in composite quantum systems in terms of symplectic geometry. We provide a symplectic characterization of sets of equally entangled states as orbits of group actions in the space of states. In particular, using Kostant-Sternberg theorem, we show that separable states form a unique Kaehler orbit, whereas orbits of entanglement states are characterized by different degrees of degeneracy of the canonical symplectic form on the complex projective space. The degree of degeneracy may be thus used as a new geometric measure of entanglement and we show how to calculate it for various multiparticle systems providing also simple criteria of separability. The presented method is general and can be applied also under different additional symmetry conditions stemming, eg. from the indistinguishability of particles.Comment: LaTex, 31 pages, typos correcte

A mathematical model for the onset of avascular tumor growth in response to the loss of p53 function

We present a mathematical model for the formation of an avascular tumor based on the loss by gene mutation of the tumor suppressor function of p53. The wild type p53 protein regulates apoptosis, cell expression of growth factor and matrix metalloproteinase, which are regulatory functions that many mutant p53 proteins do not possess. The focus is on a description of cell movement as the transport of cell population density rather than as the movement of individual cells. In contrast to earlier works on solid tumor growth, a model is proposed for the initiation of tumor growth. The central idea, taken from the mathematical theory of dynamical systems, is to view the loss of p53 function in a few cells as a small instability in a rest state for an appropriate system of differential equations describing cell movement. This instability is shown (numerically) to lead to a second, spatially inhomogeneous, solution that can be thought of as a solid tumor whose growth is nutrient diffusion limited. In this formulation, one is led to a system of nine partial differential equations. We show computationally that there can be tumor states that coexist with benign states and that are highly unstable in the sense that a slight increase in tumor size results in the tumor occupying the sample region while a slight decrease in tumor size results in its ultimate disappearance

Ecosystem services for intensification of agriculture, with emphasis on increased nitrogen ecological use efficiency

Funding Information: This work was undertaken as part of NUCLEUS, a virtual joint center to deliver enhanced N-use efficiency via an integrated soil?plant systems approach for the United Kingdom and Brazil. This work was funded in Brazil by FAPESP-S?o Paulo Research Foundation (Grant Number 2015/50305-8), FAPEG-Goi?s Research Foundation (Grant Number 2015-10267001479), and FAPEMA-Maranh?o Research Foundation (Grant Number RCUK-02771/16); and in the United Kingdom by the Biotechnology and Biological Sciences Research Council (Grant Number BB/N013201/1) under the Newton Fund scheme.Peer reviewedPublisher PD