Identification of non-cross-reacting antigens of Onchocerca volvulus with lymphatic filariasis serum pools

Onchocerca volvulus proteins labelled with 125I were immunoprecipitated with onchocerciasis and lymphatic filariasis human serum pools in order to differentiate between cross-reacting and non-cross-reacting antigens. Analysis of the immunoprecipitates by two-dimensional gel electrophoresis revealed that all high molecular weight (Mr) O. volvulus antigens cross-reacted with the lymphatic filariasis serum pools. We observed, however, that at least 8 0. volvulus antigens were specifically immunoprecipitated only by the onchocerciasis serum pools, with Mr ranging from 20000 up to 43000 Daltons. These results suggest that the lower Mr O. volvulus antigens are more species specific than the other antigens. The significance of these findings for the immunodiagnosis of onchocerciasis is discusse

Conductance through an array of quantum dots

We propose a simple approach to study the conductance through an array of $N$ interacting quantum dots, weakly coupled to metallic leads. Using a mapping to an effective site which describes the low-lying excitations and a slave-boson representation in the saddle-point approximation, we calculated the conductance through the system. Explicit results are presented for N=1 and N=3: a linear array and an isosceles triangle. For N=1 in the Kondo limit, the results are in very good agreement with previous results obtained with numerical renormalization group (NRG). In the case of the linear trimer for odd $N$, when the parameters are such that electron-hole symmetry is induced, we obtain perfect conductance $G_0=2e^2/h$. The validity of the approach is discussed in detail.Comment: to appear in Phys. Rev.

Country Natural Beef: A Maturing Co-op at the Crossroads

A Business Base Study of a Group of Northwest Cattle Ranchers that Formed a Co-op to Market Natural Beef Products, in the Face of economic uncertainty and the rise of corporate farms and ranches. Provides an overview of the cattle ranching industry, the history of the co-op, its economic outlook, and future challenges

Comparison of different trap designs for capture of noctuid moths (Lepidoptera: Noctuidae) with pheromone and floral odor attractants

Six trap designs were assessed for capturing noctuid moths in field trials in the UK and Argentina. The traps were baited with either a sex pheromone for Autographa gamma in the UK trials and Helicoverpa gelotopoeon in Argentina, or a floral odor blend. In the UK trials the Universal Trap and a funnel sleeve trap were compared; in Argentina the funnel sleeve trap, a homemade bucket trap, and three sticky traps: LepTrap, wing trap, and delta trap were compared. Comparisons were made between the traps and attractants and captures of noctuid moths and non-target insects. Traps baited with the floral attractant caught a lower number but a wider range of noctuid species including Helicoverpa, Spodoptera, Rachiplusia, Dargida, Mythimna, Chrysodeixis, Agrotis, and Autographa spp, and non-target insects. In the UK trials, the funnel sleeve trap caught significantly more A. gamma than the Universal Trap. The addition of an insecticide to the Universal Trap marginally increased trap catches. In the Argentinian trials, the homemade bucket and the sleeve traps outperformed all sticky traps in most situations regardless of crop environment and attractant type. The homemade bucket and the funnel sleeve traps are also considerably cheaper than the other trap designs. Of the sticky traps the LepTrap caught more noctuids than the wing and delta traps. The results suggest that the bucket trap and the sleeve trap have a much greater maximum capacity and possibly a greater retention efficiency for noctuid moths compared to the sticky traps

Dissipation-driven superconductor-insulator transition in linear arrays of Josephson junctions capacitively coupled to metallic films

We study the low-temperature properties of linear Josephson-junction arrays capacitively coupled to a proximate two-dimensional diffusive metal. Using bosonization techniques, we derive an effective model for the array and obtain its critical properties and phases at T = 0 using a renormalization group analysis and a variational approach. While static screening effects given by the presence of the metal can be absorbed in a renormalization of the parameters of the array, backscattering originated in the dynamically screened Coulomb interaction produces a non-trivial stabilization of the insulating groundstate and can drive a superconductor-insulator transition. We study the consequences for the transport properties in the low-temperature regime. In particular, we calculate the resisitivity as a function of the temperature and the parameters of the array, and obtain clear signatures of a superconductor-insulator transition that could be observed in experiments.Comment: 10 pages, 5 figures, submitted to Physical Review

Genome sequence of Acetomicrobium hydrogeniformans OS1

Acetomicrobium hydrogeniformans, an obligate anaerobe of the phylum Synergistetes, was isolated from oil production water. It has the unusual ability to produce almost 4 molecules H2/molecule glucose. The draft genome of A. hydrogeniformans OS1 (DSM 22491T) is 2,123,925 bp, with 2,068 coding sequences and 60 RNA genes

Dissipative phase-fluctuations in superconducting wires capacitively coupled to diffusive metals

We study the screening of the Coulomb interaction in a quasi one-dimensional superconductor given by the presence of either a one- or a two-dimensional non-interacting electron gas. To that end, we derive an effective low-energy phase-only action, which amounts to treating the Coulomb and superconducting correlations in the random-phase approximation. We concentrate on the study of dissipation effects in the superconductor, induced by the effect of Coulomb coupling to the diffusive density-modes in the metal, and study its consequences on the static and dynamic conductivity. Our results point towards the importance of the dimensionality of the screening metal in the behavior of the superconducting plasma mode of the wire at low energies. In absence of topological defects, and when the screening is given by a one-dimensional electron gas, the superconducting plasma mode is completely damped in the limit $q\to 0$, and consequently superconductivity is lost in the wire. In contrast, we recover a Drude-response in the conductivity when the screening is provided by a two-dimensional electron gas.Comment: 16 pages, 8 figures, 1 table, 2 appendice

Evidencias de la divergencia entre la visualización y el razonamiento geométrico

El presente estudio tiene por objetivo exponer las principales problemáticas que intervienen en el desarrollo del proceso de enseñanza-aprendizaje asociados a la geometría elemental. Apoyados por la literatura y a través de un cuestionario de tres preguntas; se pondrá en evidencia cómo estudiantes de 8° básico han ido construyendo sus conocimientos geométricos en base a aprendizajes memorísticos y disconexos; lo que presenta un gran obstáculo en el posterior proceso de desarrollo y apropiación de habilidades como la visualización, razonamiento y justificación. Con base en las respuestas obtenidas identificamos que la noción de ciertos elementos principales de la geometría están construidas por apreciaciones visuales más que por características y/o representaciones conceptuales

Crystal-field effects in the mixed-valence compounds Yb2M3Ga9 (M= Rh, Ir)

Magnetic susceptibility, heat capacity, and electrical resistivity measurements have been carried out on single crystals of the intermediate valence compounds Yb2Rh3Ga9 and Yb2Ir3Ga9. These measurements reveal a large anisotropy due apparently to an interplay between crystalline electric field (CEF) and Kondo effects. The temperature dependence of magnetic susceptibility can be modelled using the Anderson impurity model including CEF within an approach based on the Non-Crossing Approximation.Comment: Accepted to Phys. Rev.