Decoding transcription and microRNA-mediated translation control in Drosophila development

The spatio-temporal regulation of gene expression lies at the heart of animal development. In this article we present an overview of our recent work to apply systems biological approaches to the study of transcription and microRNA-mediated translation control in Drosophila development. We have identified many new cis-regulatory elements within the segmentation gene network, a transcriptional hierarchy governing pattern formation along the antero-posterior axis of the embryo, and developed a novel thermodynamic model to predict their expression. A similar thermodynamic approach that takes into account the secondary structure of the target mRNA significantly improves the prediction of microRNA binding sites

A partially linear approach to modelling the dynamics of spot and futures prices

In this paper we consider the dynamics of spot and futures prices in the presence of arbitrage. We propose a partially linear error correction model where the adjustment coefficient is allowed to depend non-linearly on the lagged price difference. We estimate our model using data on the DAX index and the DAX futures contract. We find that the adjustment is indeed nonlinear. The linear alternative is rejected. The speed of price adjustment is increasing almost monotonically with the magnitude of the price difference

Bose-Einstein condensation in a minimal inhomogeneous system

We study the effects of repulsive interaction and disorder on Bosons in a two-site Bose-Hubbard system, which provides a simple model of the dirty boson problem. By comparison with exact numerical results, we demonstrate how a straightforward application of the Bogoliubov approximation fails even to deliver a qualitatively correct picture: It wrongly predicts an increase of the condensate depletion due to disorder. We show that, in the presence of disorder, the noncommutative character of the condensate operator has to be retained for a correct description of the system.Comment: 6 pages, 4 figure

Zeroth order regular approximation approach to electric dipole moment interactions of the electron

A quasi-relativistic two-component approach for an efficient calculation of $\mathcal{P,T}$-odd interactions caused by a permanent electric dipole moment of the electron (eEDM) is presented. The approach uses a (two-component) complex generalized Hartree-Fock (cGHF) and a complex generalized Kohn-Sham (cGKS) scheme within the zeroth order regular approximation (ZORA). In applications to select heavy-elemental polar diatomic molecular radicals, which are promising candidates for an eEDM experiment, the method is compared to relativistic four-component electron-correlation calculations and confirms values for the effective electrical field acting on the unpaired electron for RaF, BaF, YbF and HgF. The calculations show that purely relativistic effects, involving only the lower component of the Dirac bi-spinor, are well described by treating only the upper component explicitly.Comment: 10 pages, 4 tables, supplementary materia

Condensate deformation and quantum depletion of Bose-Einstein condensates in external potentials

The one-body density matrix of weakly interacting, condensed bosons in external potentials is calculated using inhomogeneous Bogoliubov theory. We determine the condensate deformation caused by weak external potentials on the mean-field level. The momentum distribution of quantum fluctuations around the deformed ground state is obtained analytically, and finally the resulting quantum depletion is calculated. The depletion due to the external potential, or potential depletion for short, is a small correction to the homogeneous depletion, validating our inhomogeneous Bogoliubov theory. Analytical results are derived for weak lattices and spatially correlated random potentials, with simple, universal results in the Thomas-Fermi limit of very smooth potentials.Comment: 17 pages, 4 figures. v2: published version, minor change

Lotsize optimization leading to a pp-median problem with cardinalities

We consider the problem of approximating the branch and size dependent demand of a fashion discounter with many branches by a distributing process being based on the branch delivery restricted to integral multiples of lots from a small set of available lot-types. We propose a formalized model which arises from a practical cooperation with an industry partner. Besides an integer linear programming formulation and a primal heuristic for this problem we also consider a more abstract version which we relate to several other classical optimization problems like the p-median problem, the facility location problem or the matching problem.Comment: 14 page

Ag Bankers -- Today and Tomorrow

A survey of 401 Iowa bank executives was conducted in October 2008. We received 106 valid responses. The survey requested information on expected loan growth and staffing levels for agricultural credit professionals over the next decade. In addition respondents reported the desired training and experience and expected compensation of new hires. Bank executives expect agricultural loans to grow over the next decade but at a slower rate than total loans. A gain in agricultural loan officer employment is expected net of retirements. Bank executives reported that soft skills such as problem solving ability and communication were more important for new agricultural loan officers than formal training in agriculture or business. Expected compensation levels and growth for new hires tend to lag those in competing industries.agricultural loan officer; employment; compensation; training; survey

A grand-canonical approach to the disordered Bose gas

We study the problem of disordered interacting bosons within grand-canonical thermodynamics and Bogoliubov theory. We compute the fractions of condensed and non-condensed particles and corrections to the compressibility and the speed of sound due to interaction and disorder. There are two small parameters, the disorder strength compared to the chemical potential and the dilute-gas parameter.Comment: 9 pages, 3 figure

Spin-dependent THz oscillator based on hybrid graphene superlattices

We theoretically study the occurrence of Bloch oscillations in biased hybrid graphene systems with spin-dependent superlattices. The spin-dependent potential is realized by a set of ferromagnetic insulator strips deposited on top of a gapped graphene nanoribbon, which induce a proximity exchange splitting of the electronic states in the graphene monolayer. We numerically solve the Dirac equation and study Bloch oscillations in the lowest conduction band of the spin-dependent superlattice. While the Bloch frequency is the same for both spins, we find the Bloch amplitude to be spin dependent. This difference results in a spin-polarized ac electric current in the THz range.Comment: 4 pages, 6 figure