Analytical study of an exclusive genetic switch

The nonequilibrium stationary state of an exclusive genetic switch is considered. The model comprises two competing species and a single binding site which, when bound to by a protein of one species, causes the other species to be repressed. The model may be thought of as a minimal model of the power struggle between two competing parties. Exact solutions are given for the limits of vanishing binding/unbinding rates and infinite binding/unbinding rates. A mean field theory is introduced which is exact in the limit of vanishing binding/unbinding rates. The mean field theory and numerical simulations reveal that generically bistability occurs and the system is in a symmetry broken state. An exact perturbative solution which in principle allows the nonequilibrium stationary state to be computed is also developed and computed to first and second order.Comment: 28 pages, 6 figure

Collapse of the Gd3+Gd^{3+} ESR fine structure throughout the coherent temperature of the Gd-doped Kondo Semiconductor CeFe4P12CeFe_{4}P_{12}

Experiments on the $Gd^{3+}$ Electron Spin Resonance (ESR) in the filled skutterudite $Ce_{1-x}Gd_{x}Fe_{4}P_{12}$ ($x \approx 0.001$), at temperatures where the host resistivity manifests a smooth insulator-metal crossover, provides evidence of the underlying Kondo physics associated with this system. At low temperatures (below $T \approx K$), $Ce_{1-x}Gd_{x}Fe_{4}P_{12}$ behaves as a Kondo-insulator with a relatively large hybridization gap, and the $Gd^{3+}$ ESR spectra displays a fine structure with lorentzian line shape, typical of insulating media. The electronic gap is attributed to the large hybridization present in the coherent regime of a Kondo lattice, when Ce 4f-electrons cooperate with band properties at half-filling. Mean-field calculations suggest that the electron-phonon interaction is fundamental at explaining the strong 4f-electron hybridization in this filled skutterudite. The resulting electronic structure is strongly temperature dependent, and at about $T^{*} \approx 160 K$ the system undergoes an insulator-to-metal transition induced by the withdrawal of 4f-electrons from the Fermi volume, the system becoming metallic and non-magnetic. The $Gd^{3+}$ ESR fine structure coalesces into a single dysonian resonance, as in metals. Still, our simulations suggest that exchange-narrowing via the usual Korringa mechanism, alone, is not capable of describing the thermal behavior of the ESR spectra in the entire temperature region ($4.2$ - $300$ K). We propose that temperature activated fluctuating-valence of the Ce ions is the missing ingredient that, added to the usual exchange-narrowing mechanism, fully describes this unique temperature dependence of the $Gd^{3+}$ ESR fine structure observed in $Ce_{1-x}Gd_{x}Fe_{4}P_{12}$.Comment: 19 pages, 6 figure

Asymptotic entanglement in a two-dimensional quantum walk

The evolution operator of a discrete-time quantum walk involves a conditional shift in position space which entangles the coin and position degrees of freedom of the walker. After several steps, the coin-position entanglement (CPE) converges to a well defined value which depends on the initial state. In this work we provide an analytical method which allows for the exact calculation of the asymptotic reduced density operator and the corresponding CPE for a discrete-time quantum walk on a two-dimensional lattice. We use the von Neumann entropy of the reduced density operator as an entanglement measure. The method is applied to the case of a Hadamard walk for which the dependence of the resulting CPE on initial conditions is obtained. Initial states leading to maximum or minimum CPE are identified and the relation between the coin or position entanglement present in the initial state of the walker and the final level of CPE is discussed. The CPE obtained from separable initial states satisfies an additivity property in terms of CPE of the corresponding one-dimensional cases. Non-local initial conditions are also considered and we find that the extreme case of an initial uniform position distribution leads to the largest CPE variation.Comment: Major revision. Improved structure. Theoretical results are now separated from specific examples. Most figures have been replaced by new versions. The paper is now significantly reduced in size: 11 pages, 7 figure

Contribución a la caracterización productiva del cerdo manchado de Jabugo en el período predestete: resultados preliminares

En este trabajo se estudia el comportamiento de la raza Manchado de Jabugo en el periodo predestete con vistas a la caracterización productiva de la raza en este estadio fisiológico. Para ello se analiza una muestra de 140 animales entre machos y hembras. De los resultados obtenidos se desprende un peso al nacimiento medio en torno a 1,6 kg, un peso medio al destete alrededor de 12,5 kg y una ganancia media diaria en el periodo 0-60 días de 206 gramos/día. Se concluye que el Manchado de Jabugo presenta un peso al nacimiento mayor al descrito en el resto de las razas porcinas autóctonas españolas (diferentes variedades de cerdo Ibérico, Chato Murciano y Negro Canario) y una menor capacidad de crecimiento en las primeras fases de vida en comparación a dichas razas. Las variables estudiadas nos informan de un escaso dimorfismo sexual en la raza

Matching fields of a long superconducting film

We obtain the vortex configurations, the matching fields and the magnetization of a superconducting film with a finite cross section. The applied magnetic field is normal to this cross section, and we use London theory to calculate many of its properties, such as the local magnetic field, the free energy and the induction for the mixed state. Thus previous similar theoretical works, done for an infinitely long superconducting film, are recovered here, in the special limit of a very long cross section.Comment: Contains a REVTeX file and 4 figure

Registration of Great Northern Common Bean Cultivar ‘Coyne’ with Enhanced Disease Resistance to Common Bacterial Blight and Bean Rust

Great northern common bean (Phaseolus vulgaris L.) ‘Coyne’ (Reg. No. CV-287, PI 655574) was developed by the dry bean breeding program at the University of Nebraska Agricultural Research Division and released in 2008. It was bred specifically for adaptation to Nebraska growing conditions and for enhanced resistance to common bacterial blight (CBB), a major disease of common bean caused by the seed-borne bacterium Xanthomonas campestris pv. phaseoli (Smith) Dye, and bean common rust Uromyces appendiculatus (Pers.:Pers) Unger. Coyne is a great northern F7:8 line derived from a three-way cross (G95023/Weihing//BelMiNeb-RMR-11). The first cross was made in winter 2003. The F7:8 was tested in advanced yield trials at Scottsbluff and Mitchell, NE, and in growers’ fields in Nebraska. Yield of Coyne was only 47 kg ha–1 lower than ‘Marquis’ in Morrill and Scotts Bluff, NE, counties. Reaction of Coyne to CBB under field conditions was consistent across 3 yr at the West Central Research and Extension Center, North Platte, NE, where fi eld disease ratings of 3.2, 3.5, and 4.4 were recorded in 2005, 2006, and 2007, respectively. Coyne has the Ur-3 and Ur-6 genes for resistance to common bean rust and carries the single dominant hypersensitive I gene that provides resistance to all non-necrotic strains of Bean common mosaic virus. Coyne has bright white seed, blooms 44 d after planting, and is a midseason bean, maturing 91 d after planting

BEHAVIORAL FILTERING OF HUMAN TRAJECTORIES FOR AUTOMATIC-MULTI-TRACK INITIATION

In this paper we describe a new approach for the multitrack initiation problem. We propose an extensive use of the top-view reconstruction of the scene to solve the detection step in tracking pedestrians. We leave a large set of starting hypothetical moving objects free to evolve in the scene for a certain number of frames. The number of trajectories is pre-filtered using distance and direction constraints on a one-step movement of pedestrians. The output trajectories from pre-filtering step are then filtered using a discrete choice model for pedestrian behavior, calibrated on real data. The results show that is possible to use this technique to perform multitarget tracking in real situations. We particularly focus on an application in the context of automatic video surveillance

Method For The Production Of ?-linolenic Acid And/or Stearidonic Acid In Transgenic Brassicaceae And Linaceae (Patent WO 2007/051577 A2)

The invention relates to the production of ?-linolenic acid (18:3 ?6,9,12) or stearidonic acid (18:4 ?6,9,12,15) or ?-linolenic acid (18:3?6,9,12) and stearidonic acid (18:4 ?6,9,12,15) in transgenic plants of the brassicaceae family, said transgenic plants containing at least 10 percent by weight of oleic acid relative to the total fatty acid concentration and being provided with an increased ?-6-C18 fatty acid concentration as a result of the activity of the ?-6 desaturases used in the method. The invention also relates to novel nucleic acid sequences coding for the ?-6 desaturases used in the method, gene constructs containing said nucleic acid sequences, a vector and transgenic plants containing at least one nucleic acid sequence or a gene construct

Characterisation of fatty acyl reductases of sunflower (Helianthus annuus L.) seed

Long and very long chain fatty alcohols are produced from their corresponding acyl-CoAs through the activity of fatty acyl reductases (FARs). Fatty alcohols are important components of the cuticle that protects aerial plant organs, and they are metabolic intermediates in the synthesis of the wax esters in the hull of sunflower (Helianthus annuus) seeds. Genes encoding 4 different FARs (named HaFAR2, HaFAR3, HaFAR4 and HaFAR5) were identified using BLAST, and studies showed that four of the genes were expressed in seed hulls. In this study, the structure and location of sunflower FAR proteins were determined. They were also expressed exogenously in Saccharomyces cerevisiae to evaluate their substrate specificity based on the fatty alcohols synthesized by the transformed yeasts. Three of the four enzymes tested showed activity in yeast. HaFAR3 produced C18, C20 and C22 saturated alcohols, whereas HaFAR4 and HaFAR5 produced C24 and C26 saturated alcohols. The involvement of these genes in the synthesis of sunflower seed wax esters was addressed by considering the results obtained

Method For The Production Of Γ-linolenic Acid And/or Stearidonic Acid In Transgenic Brassicaceae And Linaceae (Patent US 8013216 B2 )

The present invention relates to the production of γ-linolenic acid (18:3Δ6,9,12) or stearidonic acid (18:4Δ6,9,12,15) or γ-linolenic acid (18:3Δ6,9,12) and stearidonic acid (18:4Δ6,9,12,15) in transgenic plants of the family Brassicaceae, where the transgenic plants comprise at least 10% by weight of oleic acid based on the total fatty acid content and, as the result of the activity of the Δ6-desaturases used in the method, have an increased Δ6-C18-fatty acid content. The invention furthermore relates to novel nucleic acid sequences which code for the Δ6-desaturases used in the method, gene constructs comprising these nucleic acid sequences, a vector and transgenic plants comprising at least one nucleic acid sequence or a gene construct