Improved efficiency of nutrient and water use for high quality field vegetable production using fertigation

Drip-based fertigation may improve the application efficiency of water and nutrients while maintaining or improving marketable yield and quality at harvest and post-harvest. Two plantings of lettuce (Lactuca sativa) were grown in the UK, with six N treatments and two methods of irrigation and N application. The conventional overhead irrigated treatments had all N applied in the base dressing with irrigation scheduled from SMD calculations. The closed loop treatments had nitrogen and irrigation delivered via drip automatically controlled by a sensor and logger system. The work established that water content in the root zone can be monitored in real time using horizontally oriented soil moisture sensors linked to data logging and telemetry, and that these data can be used to automatically trigger drip irrigation for commercially grown field vegetables. When the closed loop irrigation control was combined with fertigation treatments, lettuce crops were grown with savings of up to 60% and 75% of water and nitrogen respectively, compared to standard UK production systems. However, excess supply of N through fertigation rather than solid fertiliser was more detrimental to marketable yield and post harvest quality highlighting that care is needed when selecting N rates for fertigation

Policy Practitioners’ Accounts of Evidence-Based Policy Making: The Case of Universal Credit

This paper draws on insider accounts from UK Department for Work and Pensions (DWP) officials to analyse the relationship between evidence and policy making at a time of rapid policy development relating to Universal Credit (UC). The paper argues, firstly, that evidence selection within the DWP was constrained by the overarching austerity paradigm, which constituted a Zeitgeist and had a significant bearing on the evidence selection and translation process, sharpening the focus of policy officials and analysts on the primacy of quantitative evidence when advising Ministers. Secondly, while methodological preferences (or an ‘evidence hierarchy’) impacted on evidence selection, this was not as significant as practitioners’ perceived capabilities to handle and develop evidence for policy. These capabilities were linked to departmental structures and constrained by political feasibility. Together, these dimensions constituted a significant filtration mechanism determining the kinds of evidence that were selected for policy development and those omitted, particularly in relation to UC. The paper contributes to debates about the contemporary role of evidence in policymaking and the potential of the relationship between future evidence production and use

Close encounters of three black holes

We present the first fully relativistic longterm numerical evolutions of three equal-mass black holes in a system consisting of a third black hole in a close orbit about a black-hole binary. We find that these close-three-black-hole systems have very different merger dynamics from black-hole binaries. In particular, we see complex trajectories, a redistribution of energy that can impart substantial kicks to one of the holes, distinctive waveforms, and suppression of the emitted gravitational radiation. We evolve two such configurations and find very different behaviors. In one configuration the binary is quickly disrupted and the individual holes follow complicated trajectories and merge with the third hole in rapid succession, while in the other, the binary completes a half-orbit before the initial merger of one of the members with the third black hole, and the resulting two-black-hole system forms a highly elliptical, well separated binary that shows no significant inspiral for (at least) the first t~1000M of evolution.Comment: 4 pages, 5 figure

Mesh-free simulation of complex LCD geometries

We use a novel mesh-free simulation approach to study the post aligned bistable nematic (PABN) cell. By employing the Qian-Sheng formalism for liquid crystals along with a smooth representation of the surface posts, we have been able to identify two distinct stable configurations. The three-dimensional order field configurations of these states and their elastic free energies are consistent with both experimental results and previous simulation attempts. However, alternative states suggested in previous studies do not appear to remain stable when finite post curvature is considered.</p

Cancer: A new role for an old enemy

Drugs that change the shape of AKT, a protein kinase that promotes tumor growth, may be more effective than drugs that only target its enzymatic activity

Composition Mixing during Blue Straggler Formation and Evolution

We use smoothed-particle hydrodynamics to examine differences between direct collisions of single stars and binary star mergers in their roles as possible blue straggler star formation mechanisms. We find in all cases that core helium in the progenitor stars is largely retained in the core of the remnant, almost independent of the type of interaction or the central concentration of the progenitor stars. We have also modelled the subsequent evolution of the hydrostatic remnants, including mass loss and energy input from the hydrodynamical interaction. The combination of the hydrodynamical and hydrostatic models enables us to predict that little mixing will occur during the merger of two globular cluster stars of equal mass. In contrast to the results of Proctor Sills, Bailyn, & Demarque (1995), we find that neither completely mixed nor unmixed models can match the absolute colors of observed blue stragglers in NGC 6397 at all luminosity levels. We also find that the color distribution is probably the crucial test for explanations of BSS formation - if stellar collisions or mergers are the correct mechanisms, a large fraction of the lifetime of the straggler must be spent away from the main sequence. This constraint appears to rule out the possibility of completely mixed models. For NGC 6397, unmixed models predict blue straggler lifetimes ranging from about 0.1 to 4 Gyr, while completely mixed models predict a range from about 0.6 to 4 Gyr.Comment: AASTeX, 28 pg., accepted for ApJ, also available at http://ucowww.ucsc.edu/~erics/bspaper.htm

The human ovarian surface epithelium is an androgen responsive tissue

The pathogenesis of epithelial ovarian cancer remains unclear. From epidemiological studies raised levels of androgens have been implicated to increase the risk of developing the disease. The purpose of this study was to determine the responses of normal human ovarian surface epithelium to androgens. We have established primary cultures of human ovarian surface epithelium from patients undergoing oophorectomy for benign disease. Total RNA was isolated from these cultures and expression of mRNA encoding for the androgen receptor was demonstrated using reverse transcriptase polymerase chain reaction. The presence of androgen receptor in sections of normal ovary was also investigated using an antibody against androgen receptor. The effects of androgens on DNA synthesis and cell death were determined. Eight out of eight (100%) cultures expressed mRNA encoding the androgen receptor. The presence of androgen receptor in ovarian surface epithelium of sections of normal ovaries was demonstrated in all sections. Mibolerone, a synthetic androgen, caused a significant stimulation of DNA synthesis in 5 out of 9 (55%) cultures when used at a concentration of 1 nM. Mibolerone also caused a significant decrease in cell death in 2 out of 5 (40%) cultures tested. We have demonstrated that the ovarian surface epithelium is an androgen responsive tissue and that androgens can cause an increase in proliferation and a decrease in cell death. These findings have important implications for the pathophysiology of ovarian carcinogenesis

Equilibrium Configurations of Strongly Magnetized Neutron Stars with Realistic Equations of State

We investigate equilibrium sequences of magnetized rotating stars with four kinds of realistic equations of state (EOSs) of SLy (Douchin et al.), FPS (Pandharipande et al.), Shen (Shen et al.), and LS (Lattimer & Swesty). Employing the Tomimura-Eriguchi scheme to construct the equilibrium configurations. we study the basic physical properties of the sequences in the framework of Newton gravity. In addition we newly take into account a general relativistic effect to the magnetized rotating configurations. With these computations, we find that the properties of the Newtonian magnetized stars, e.g., structure of magnetic field, highly depends on the EOSs. The toroidal magnetic fields concentrate rather near the surface for Shen and LS EOSs than those for SLy and FPS EOSs. The poloidal fields are also affected by the toroidal configurations. Paying attention to the stiffness of the EOSs, we analyze this tendency in detail. In the general relativistic stars, we find that the difference due to the EOSs becomes small because all the employed EOSs become sufficiently stiff for the large maximum density, typically greater than $10^{15}\rm{g} \rm{cm}^{-3}$. The maximum baryon mass of the magnetized stars with axis ratio $q\sim 0.7$ increases about up to twenty percents for that of spherical stars. We furthermore compute equilibrium sequences at finite temperature, which should serve as an initial condition for the hydrodynamic study of newly-born magnetars. Our results suggest that we may obtain information about the EOSs from the observation of the masses of magnetars.Comment: submitted to MNRA

Tidal spin-up of stars in dense stellar cusps around massive black holes

We show that main-sequence stars in dense stellar cusps around massive black holes are likely to rotate at a significant fraction of the centrifugal breakup velocity due to spin-up by hyperbolic tidal encounters. We use realistic stellar structure models to calculate analytically the tidal spin-up in soft encounters, and extrapolate these results to close and penetrating collisions using smoothed particle hydrodynamics simulations. We find that the spin-up falls off only slowly with distance from the black hole because the increased tidal coupling in slower collisions at larger distances compensates for the decrease in the stellar density. We apply our results to the stars near the massive black hole in the Galactic Center. Over their lifetime, ~1 Msol main sequence stars in the inner 0.3 pc of the Galactic Center are spun-up on average to ~10%--30% of the centrifugal breakup limit. Such rotation is ~20--60 times higher than is usual for such stars and may affect their subsequent evolution and their observed properties.Comment: 25 pages, 7 figures. Submitted to Ap

Human tumour xenografts established and serially transplanted in mice immunologically deprived by thymectomy, cytosine arabinoside and whole-body irradiation.

Mice immunologically deprived by thymectomy, cytosine arabinoside treatment and whole-body irradiation were used to study the growth of human tumours as xenografts. 10/16 melanoma biopsies, 4/13 ovarian carcinoma biopsies and 3/6 uterine cancer biopsies grew as serially transpllantable xenograft lines. The tumour lines were studied through serial passages by histology, histochemistry, electron microscopy, chromosome analysis, immune fluorescence, growth rate measurement and mitotic counts. They retained the characteristics of the tumours of origin, with the exception of loss of pigmentation in two melanomas, histological dedifferentiation in the uterine carcinomas, and increased mitotic frequency and growth rate in some melanomas. It was concluded that this type of animal preparation is as useful as alternative methods of immunological deprivation, or as athymic nude mice, for the growth of human tumour xenografts, at least for some experimental purposes