High current source of He −

A negative helium ion beam of 70 mA at 10.5 kV has been produced by charge exchange in sodium. The production is studied as a function of sodium line density, beam energy and background helium gas density. The characteristics of this high current He{sup -} source are analyzed to determine the design requirements for He{sup -} beam generation in the range of tens to hundred of milliamperes

Competing order, Fermi surface reconstruction, and quantum oscillations in underdoped high temperature superconductors

We consider incommensurate $d$-density wave order in underdoped high temperature superconductors. We find that Fermi surface reconstruction can correctly capture the phenomenology of the recent quantum oscillation experiments that suggest incommensurate order. The predicted frequencies are a frequency around 530 T arising from the electron pocket, a hole frequency at around 1650 T, and a new low frequency from a smaller hole pocket at 250 T for which there are some indications that require further investigation. The oscillation corresponding to the electron pocket will be further split due to bilayer coupling but the splitting is sufficiently small to require more refined measurements. The truly incommensurate $d$-density wave breaks both time reversal and inversion but the product of these two symmetry operations is preserved. There is some similarity of our results with the spiral spin density wave order, which, as pointed out by Overhauser, also breaks time reversal and inversion. Calculations corresponding to higher order commensuration produces results similar to anti-phase spin stripes, but appear to us to be an unlikely explanation of the experiments. The analysis of the Gorkov equation in the mixed state shows that the oscillation frequencies are unshifted from the putative normal state and the additional Dingle factor arising from the presence of the mixed state can provide a subtle distinction between the spiral spin density wave and the $d$-density wave.Comment: 16 pages and 8 figure

Microfluidic and Nanofluidic Cavities for Quantum Fluids Experiments

The union of quantum fluids research with nanoscience is rich with opportunities for new physics. The relevant length scales in quantum fluids, 3He in particular, are comparable to those possible using microfluidic and nanofluidic devices. In this article, we will briefly review how the physics of quantum fluids depends strongly on confinement on the microscale and nanoscale. Then we present devices fabricated specifically for quantum fluids research, with cavity sizes ranging from 30 nm to 11 microns deep, and the characterization of these devices for low temperature quantum fluids experiments.Comment: 12 pages, 3 figures, Accepted to Journal of Low Temperature Physic

Aspects of the methodology validation for light filth in fruit pulp

Methodology validation is an important tool to support the activities of metrology in the quantification analysis. Extraneous materials may be present in the pulps due to the conditions or the practices of production, storage and distribution. Since there is no specific methodology for fruit pulp light filth quantification a research has been carried out to test two methods for isolation of light filth in mango, strawberry, tomato and guava pulps. For guava, mango and tomato pulps the AOAC Official Method 964.23 was used, and for strawberry pulp AOAC Official Method 950.89, with adaptations. The micro-analytic standard for insect fragment and rodent hair was prepared in the laboratory. The study has been conducted on 63 samples of 100 g of pulp analyzed in duplicate after contamination with 5, 15, 30 insect fragments (IF) per 100 g and 5, 10, 15 rodent hair (RH) per 100 g, with blank samples as a control. The validation parameters used were precision and accuracy. Recovery of insect fragment was considered stisfactory in mango, tomato, guava pulps, and the average recovery ranged from 87 to 96%. For strawberry pulp, the recovery rate ranged from 68 to 80%. For rodent hairs, the best recovery rate was observed in mango pulp ranging from 73 to 81%, followed by guava pulp ranging from 65 to 76%, tomato pulp ranging from 50 to 67%, and strawberry pulp ranging from 33 to 35%. It was concluded that the methodologies used to detect light filth in guava, mango, tomato and strawberry pulps can be adopted in the monitoring routine of fruit pulp extraneous material contamination even though they were found not very efficient for rodent hairs. Keywords: Insect fragment, Rodent hair, AOAC determination method, Recovery rate, Fruit pulp

A Novel Long Range Spin Chain and Planar N=4 Super Yang-Mills

We probe the long-range spin chain approach to planar N=4 gauge theory at high loop order. A recently employed hyperbolic spin chain invented by Inozemtsev is suitable for the SU(2) subsector of the state space up to three loops, but ceases to exhibit the conjectured thermodynamic scaling properties at higher orders. We indicate how this may be bypassed while nevertheless preserving integrability, and suggest the corresponding all-loop asymptotic Bethe ansatz. We also propose the local part of the all-loop gauge transfer matrix, leading to conjectures for the asymptotically exact formulae for all local commuting charges. The ansatz is finally shown to be related to a standard inhomogeneous spin chain. A comparison of our ansatz to semi-classical string theory uncovers a detailed, non-perturbative agreement between the corresponding expressions for the infinite tower of local charge densities. However, the respective Bethe equations differ slightly, and we end by refining and elaborating a previously proposed possible explanation for this disagreement.Comment: 48 pages, 1 figure. v2, further results added: discussion of the relationship to an inhomogeneous spin chain, normalization in sec 3 unified, v3: minor mistakes corrected, published versio

Yang-Mills Correlation Functions from Integrable Spin Chains

The relation between the dilatation operator of N=4 Yang-Mills theory and integrable spin chains makes it possible to compute the one-loop anomalous dimensions of all operators in the theory. In this paper we show how to apply the technology of integrable spin chains to the calculation of Yang-Mills correlation functions by expressing them in terms of matrix elements of spin operators on the corresponding spin chain. We illustrate this method with several examples in the SU(2) sector described by the XXX_1/2 chain.Comment: 27 pages, 3 figures, harvma

Semiclassical Strings on AdS_5 x S^5/Z_M and Operators in Orbifold Field Theories

We show agreements, at one-loop level of field theory, between energies of semiclassical string states on AdS_5 x S^5/Z_M and anomalous dimensions of operators in N=0,1,2 orbifold field theories originating from N=4 SYM. On field theory side, one-loop anomalous dimension matrices can be regarded as Hamiltonians of spin chains with twisted boundary conditions. These are solvable by Bethe ansatz. On string side, twisted sectors emerge and we obtain some string configurations in twisted sectors. In SU(2) subsectors, we compare anomalous dimensions with string energies and see agreements. We also see agreements between sigma models of both sides in SU(2) and SU(3) subsectors.Comment: LaTeX, 23 pages, 4 figures; v2 minor corrections, added references; v3 typos corrected, published versio

Expression of LIM kinase 1 is associated with reversible G1/S phase arrest, chromosomal instability and prostate cancer

<p>Abstract</p> <p>Background</p> <p>LIM kinase 1 (LIMK1), a LIM domain containing serine/threonine kinase, modulates actin dynamics through inactivation of the actin depolymerizing protein cofilin. Recent studies have indicated an important role of LIMK1 in growth and invasion of prostate and breast cancer cells; however, the molecular mechanism whereby LIMK1 induces tumor progression is unknown. In this study, we investigated the effects of ectopic expression of LIMK1 on cellular morphology, cell cycle progression and expression profile of LIMK1 in prostate tumors.</p> <p>Results</p> <p>Ectopic expression of LIMK1 in benign prostatic hyperplasia cells (BPH), which naturally express low levels of LIMK1, resulted in appearance of abnormal mitotic spindles, multiple centrosomes and smaller chromosomal masses. Furthermore, a transient G1/S phase arrest and delayed G2/M progression was observed in BPH cells expressing LIMK1. When treated with chemotherapeutic agent Taxol, no metaphase arrest was noted in these cells. We have also noted increased nuclear staining of LIMK1 in tumors with higher Gleason Scores and incidence of metastasis.</p> <p>Conclusion</p> <p>Our results show that increased expression of LIMK1 results in chromosomal abnormalities, aberrant cell cycle progression and alteration of normal cellular response to microtubule stabilizing agent Taxol; and that LIMK1 expression may be associated with cancerous phenotype of the prostate.</p