5,823 research outputs found

    Detecting paired and counterflow superfluidity via dipole oscillations

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    We suggest an experimentally feasible procedure to observe paired and counterflow superfluidity in ultra-cold atom systems. We study the time evolution of one-dimensional mixtures of bosonic atoms in an optical lattice following an abrupt displacement of an additional weak confining potential. We find that the dynamic responses of the paired superfluid phase for attractive inter-species interactions and the counterflow superfluid phase for repulsive interactions are qualitatively distinct and reflect the quasi long-range order that characterizes these states. These findings suggest a clear experimental procedure to detect these phases, and give an intuitive insight into their dynamics.Comment: 4 pages,5 figure

    What have we already learned from the CMB?

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    The COBE satellite, and the DMR experiment in particular, was extraordinarily successful. However, the DMR results were announced about 7 years ago, during which time a great deal more has been learned about anisotropies in the Cosmic Microwave Background (CMB). The CMB experiments currently being designed and built, including long-duration balloons, interferometers, and two space missions, promise to address several fundamental cosmological issues. We present our evaluation of what we already know, what we are beginning to learn now, and what the future may bring.Comment: 20 pages, 3 figures. Changes to match version accepted by PAS

    The Born and Lens-Lens Corrections to Weak Gravitational Lensing Angular Power Spectra

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    We revisit the estimation of higher order corrections to the angular power spectra of weak gravitational lensing. Extending a previous calculation of Cooray and Hu, we find two additional terms to the fourth order in potential perturbations of large-scale structure corresponding to corrections associated with the Born approximation and the neglect of line-of-sight coupling of two foreground lenses in the standard first order result. These terms alter the convergence (κκ\kappa\kappa), the lensing shear E-mode (ϵϵ\epsilon\epsilon), and their cross-correlation (κϵ\kappa\epsilon) power spectra on large angular scales, but leave the power spectra of the lensing shear B-mode (ββ\beta\beta) and rotational (ωω\omega\omega) component unchanged as compared to previous estimates. The new terms complete the calculation of corrections to weak lensing angular power spectra associated with both the Born approximation and the lens-lens coupling to an order in which the contributions are most significant. Taking these features together, we find that these corrections are unimportant for any weak lensing survey, including for a full sky survey limited by cosmic variance.Comment: Added references, minor changes to text. 9 pages, 2 figure

    Function of caspase-14 in trophoblast differentiation

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    <p>Abstract</p> <p>Background</p> <p>Within the human placenta, the cytotrophoblast consists of a proliferative pool of progenitor cells which differentiate to replenish the overlying continuous, multi-nucleated syncytiotrophoblast, which forms the barrier between the maternal and fetal tissues. Disruption to trophoblast differentiation and function may result in impaired fetal development and preeclampsia. Caspase-14 expression is limited to barrier forming tissues. It promotes keratinocyte differentiation by cleaving profilaggrin to stabilise keratin intermediate filaments, and indirectly providing hydration and UV protection. However its role in the trophoblast remains unexplored.</p> <p>Methods</p> <p>Using RNA Interference the reaction of control and differentiating trophoblastic BeWo cells to suppressed caspase-14 was examined for genes pertaining to hormonal, cell cycle and cytoskeletal pathways.</p> <p>Results</p> <p>Transcription of hCG, KLF4 and cytokeratin-18 were increased following caspase-14 suppression suggesting a role for caspase-14 in inhibiting their pathways. Furthermore, hCG, KLF4 and cytokeratin-18 protein levels were disrupted.</p> <p>Conclusion</p> <p>Since expression of these molecules is normally increased with trophoblast differentiation, our results imply that caspase-14 inhibits trophoblast differentiation. This is the first functional study of this unusual member of the caspase family in the trophoblast, where it has a different function than in the epidermis. This knowledge of the molecular underpinnings of trophoblast differentiation may instruct future therapies of trophoblast disease.</p

    Early Childhood Infection of Kaposi’s Sarcoma-associated Herpesvirus in Zambian Households: a Molecular Analysis

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    Sub-Saharan Africa is endemic for Kaposi’s sarcoma-associated herpesvirus (KSHV) and there is a high rate of early childhood infection; however, the transmission sources are not well characterized. We examined household members as potential KSHV transmission sources to young children in the KSHV-endemic country of Zambia. To this end, we enrolled and followed Zambian households with at least one KSHV-seropositive child and collected longitudinal buccal swab samples. KSHV burden was evaluated and K1 sequences from the children were determined and analyzed for differences to K1 sequences from household members. The K1 sequences were also analyzed for evolution over time. We generated K1 sequences from 31 individuals across 16 households. Nine households contained multiple KSHV-positive members, including at least one child. In 6 of 9 households, the child had 100% sequence identity to all household members. However, in two households the child and mother had distinct K1 sequences. In the remaining household, the children were the only KSHV-infected individuals. Furthermore, we report that 1 of 18 individuals had K1 sequence variation within the timespan analyzed. In the present study, we provide evidence that (1) early childhood KSHV transmission occurs from both within and outside the household, (2) intra-household transmission can occur via non-maternal sources, (3) viral shedding in the buccal cavity is highly variable, and (4) the dominant K1 sequence within an individual did not rapidly evolve over time. These results are important for developing KSHV intervention strategies

    Economics of Drip Irrigation for Juice Grape Vineyards in New York State

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    R.B. 99-01Grape growers need investment and cost guidelines for drip irrigation to evaluate the economics of getting vines into production as quickly as possible and to avoid periods of drought during the productive life of the vineyard. The benefits of irrigation may include: better vine survival, earlier fruit production, greater yields, more efficient distribution of nutrients, less plant stress, reduced yield variability and improved fruit quality. Research was undertaken to determine drip irrigation investment and annual costs. This project was designed to assist growers in determining the investment, fixed and variable annual costs and expected returns from drip irrigation. Irrigation suppliers provided typical equipment needs and investment costs for various drip irrigation designs. Economic worksheets are provided to assist growers in estimating fixed and variable costs of drip irrigation. The economics of yield data were applied to replicated multiyear irrigation studies to assist growers in determining yield response from drip irrigation. Net present value (NPV) methodology was used to determine the discounted break-even investment results from published responses to drip irrigation. Growers with typical drip irrigation systems and various water sources can expect investments in drip irrigation of 550to550 to 1,150 per acre with 10 acre blocks of vines. Based upon eight years of data from trials in Fredonia, NY, in the Lake Erie grape belt, average yield increases due to irrigation on establishment and growing of Niagara grapes were 2.8 ton per production year per acre, resulting in a break-even investment of approximately 1,600peracre.ButonestablishedminimalprunedConcordgrapes,sevenyearsofdatashoweda1.1tonincreaseduetoirrigationandabreakeveninvestmentofonly1,600 per acre. But on established minimal pruned Concord grapes, seven years of data showed a 1.1 ton increase due to irrigation and a break-even investment of only 200 per acre which was well below the total cost of a complete microirrigation drip system. On a new planting of Concords, with droughty soils, the analysis may very well show cost effectiveness. Growers who were interviewed were unable to quantify the benefits and costs of drip irrigation but were pleased with their irrigated yields and brix responses from drip irrigation. This analysis has provided the economic rationale for the investment in microirrigation with some varieties and under certain soil types

    Geodatabase Development to Support Hyperspectral Imagery Exploitation

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    Geodatabase development for coastal studies conducted by the Naval Research Laboratory (NRL) is essential to support the exploitation of hyperspectral imagery (HSI). NRL has found that the remote sensing and mapping science community benefits from coastal classifications that group coastal types based on similar features. Selected features in project geodatabases relate to significant biological and physical forces that shape the coast. The project geodatabases help researchers understand factors that are necessary for imagery post processing, especially those features having a high degree of temporal and spatial variability. NRL project geodatabases include a hierarchy of environmental factors that extend from shallow water bottom types and beach composition to inland soil and vegetation characteristics. These geodatabases developed by NRL allow researchers to compare features among coast types. The project geodatabases may also be used to enhance littoral data archives that are sparse. This paper highlights geodatabase development for recent remote sensing experiments in barrier island, coral, and mangrove coast types
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