1,629 research outputs found

    Studies on calcium requirements of ewes

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    Digitized 2007 AES.Includes bibliographical references (pages 34-35)

    Canonical Solution of Classical Magnetic Models with Long-Range Couplings

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    We study the canonical solution of a family of classical n−vectorn-vector spin models on a generic dd-dimensional lattice; the couplings between two spins decay as the inverse of their distance raised to the power α\alpha, with α<d\alpha<d. The control of the thermodynamic limit requires the introduction of a rescaling factor in the potential energy, which makes the model extensive but not additive. A detailed analysis of the asymptotic spectral properties of the matrix of couplings was necessary to justify the saddle point method applied to the integration of functions depending on a diverging number of variables. The properties of a class of functions related to the modified Bessel functions had to be investigated. For given nn, and for any α\alpha, dd and lattice geometry, the solution is equivalent to that of the α=0\alpha=0 model, where the dimensionality dd and the geometry of the lattice are irrelevant.Comment: Submitted for publication in Journal of Statistical Physic

    The signal peptide of pro-opiomelancortin: Validation of a specific radioimmunoassay

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    The N-terminus portion of the POMC leader sequence (signal peptide) was synthesized, and an antiserum was raised against it. A radioimmunoassay was developed which is effective at a dilution of 1:500,000, and sensitive at less than 1 fmole/tube. Since leader sequences often exhibit structural homologies, and since synthetic peptides are not readily available, we resorted to an unusual procedure to establish specificity. This involved extraction of pituitary RNA, cell-free translation to produce the pre-prohormones, and purification by B-END and signal antibody affinity columns. The eluates were then tested by SDS gel electrophoresis and by multiple immunoprecipitations. All results showed that the signal antibody captured a single molecular species, approximately 30,000 in MW, which was also captured by the B-END column, and was immunoprecipitable by B-END and ACTH antisera. It therefore appears that this antibody selectively measures the POMC leader sequence and should be valuable in measuring the newly synthesized pre-prohormone.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/23804/1/0000042.pd

    Mesoscopic modeling of a two-phase flow in the presence of boundaries: the Contact Angle

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    We present a mesoscopic model, based on the Boltzmann Equation, for the interaction between a solid wall and a non-ideal fluid. We present an analytic derivation of the contact angle in terms of the surface tension between the liquid-gas, the liquid-solid and the gas-solid phases. We study the dependency of the contact angle on the two free parameters of the model, which determine the interaction between the fluid and the boundaries, i.e. the equivalent of the wall density and of the wall-fluid potential in Molecular Dynamics studies. We compare the analytical results obtained in the hydrodynamical limit for the density profile and for the surface tension expression with the numerical simulations. We compare also our two-phase approach with some exact results for a pure hydrodynamical incompressible fluid based on Navier-Stokes equations with boundary conditions made up of alternating slip and no-slip strips. Finally, we show how to overcome some theoretical limitations connected with a discretized Boltzmann scheme and we discuss the equivalence between the surface tension defined in terms of the mechanical equilibrium and in terms of the Maxwell construction.Comment: 29 pages, 12 figure

    Zero-g radio frequency gaging system for space shuttle propellant tanks

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    Radio frequency measuring system for space shuttle propellant tanks under conditions of weightlessnes

    Histone citrullination represses miRNA expression resulting in increased oncogene mRNAs in somatolactotrope cells.

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    Peptidylarginine deiminase (PAD) enzymes convert histone arginine residues into citrulline to modulate chromatin organization and gene expression. Although PADs are expressed in anterior pituitary gland cells, their functional role and expression in pituitary adenomas is unknown. To begin to address these questions, we first examined normal human pituitaries and pituitary adenomas and found that PAD2, PAD4 and citrullinated histones are highest in prolactinomas and somatoprolactinomas. In the somatoprolactinoma-derived GH3 cell line, PADs citrullinate histone H3, which is attenuated by a pan-PAD inhibitor. RNA-sequencing and ChIP studies show that the expression of microRNAs let-7c-2, miR-23b and miR-29c is suppressed by histone citrullination. Our studies demonstrate that these miRNAs directly target the mRNA of the oncogenes HMGA, IGF-1 and N-MYC, which are highly implicated in human prolactinoma/somatoprolactinoma pathogenesis. Our results are the first to define a direct role for PAD catalyzed histone citrullination in miRNA expression, which may underlie the etiology of prolactinoma and somatoprolactinoma tumors through regulation of oncogene expression

    National and Regional Implications of Targeting the Conservation Reserve

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    Within the Conservation Reserve (CR) program, a change in program criteria could reduce the amount of erosion material entering our nation\u27s waterways. The inclusion of land adjacent to water bodies, flowing streams, and river waterways may reduce erosion from these lands and improve water quality. These buffer strip areas, removed from production and placed in the reserve with a vegetative cover, would limit sedimentation and act to prevent upland erosion materials from reaching waterway channels, thus enhancing the programs\u27 environmental benefits. This paper analyzes the economic benefits of including buffer strups as eligible CR land, and it reviews the problems of identifying such areas

    Opportunities for improving irrigation efficiency with quantitative models, soil water sensors and wireless technology

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    Increasingly serious shortages of water make it imperative to improve the efficiency of irrigation in agriculture, horticulture and in the maintenance of urban landscapes. The main aim of the current review is to identify ways of meeting this objective. After reviewing current irrigation practices, discussion is centred on the sensitivity of crops to water deficit, the finding that growth of many crops is unaffected by considerable lowering of soil water content and, on this basis, the creation of improved means of irrigation scheduling. Subsequently, attention is focused on irrigation problems associated with spatial variability in soil water and the often slow infiltration of water into soil, especially the subsoil. As monitoring of soil water is important for estimating irrigation requirements, the attributes of the two main types of soil water sensors and their most appropriate uses are described. Attention is also drawn to the contribution of wireless technology to the transmission of sensor outputs. Rapid progress is being made in transmitting sensor data, obtained from different depths down the soil profile across irrigated areas, to a PC that processes the data and on this basis automatically commands irrigation equipment to deliver amounts of water, according to need, across the field. To help interpret sensor outputs, and for many other reasons, principles of water processes in the soil–plant system are incorporated into simulation models that are calibrated and tested in field experiments. Finally, it is emphasized that the relative importance of the factors discussed in this review to any particular situation varies enormously

    Two dimensional self-avoiding walk with hydrogen-like bonding: Phase diagram and critical behaviour

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    The phase diagram for a two-dimensional self-avoiding walk model on the square lattice incorporating attractive short-ranged interactions between parallel sections of walk is derived using numerical transfer matrix techniques. The model displays a collapse transition. In contrast to the standard θ\theta-point model, the transition is first order. The phase diagram in the full fugacity-temperature plane displays an additional transition line, when compared to the θ\theta-point model, as well as a critical transition at finite temperature in the hamiltonian walk limit.Comment: 22 pages, 13 figures. To appear in Journal of Physics
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