Measurements of the Cosmological Evolution of Magnetic Fields with the Square Kilometre Array

We investigate the potential of the Square Kilometre Array (SKA) for measuring the magnetic fields in clusters of galaxies via Faraday rotation of background polarised sources. [...] We find that about 10 per cent of the sky is covered by a significant extragalactic Faraday screen. Most of it has rotation measures between 10 and 100 rad/m/m. We argue that the cluster centres should have up to about 5000 rad/m/m. We show that the proposed mid frequency aperture array of the SKA as well as the lowest band of the SKA dish array are well suited to make measurements for most of these rotation measure values, typically requiring a signal-to-noise of ten. We calculate the spacing of sources forming a grid for the purpose of measuring foreground rotation measures: it reaches a spacing of 36 arcsec for a 100 hour SKA observation per field. We also calculate the statistics for background RM measurements in clusters of galaxies. We find that a first phase of the SKA would allow us to take stacking experiments out to high redshifts (>1), and provide improved magnetic field structure measurements for individual nearby clusters. The full SKA aperture array would be able to make very detailed magnetic field structure measurements of clusters with more than 100 background sources per cluster up to a redshift of 0.5 and more than 1000 background sources per cluster for nearby clusters, and could for reasonable assumptions about future measurements of electron densities in high redshift clusters constrain the power law index for the magnetic field evolution to better than dm=0.4, if the magnetic field in clusters should follow B ~ (1+z)^m.Comment: 12 pages, 10 figures, 3 tables, accepted by MNRAS, minor correction to eq (5

Development of Procedures to Evaluate Salinity Management Strategies in Irrigation Return Flows

The salinity added irrigation return flows is a major problem in rivers draining agricultural lands throughout the arid regions of the world, and many irrigation water management alternatives have been proposed for reducing downstream salinity problems. The merits of these alternatives, however, can only be judged from reliable information on their actual effects on the salinity in rivers receiving the drainage water and the water withdrawn from the river by downstream users. Hydrosalinity models are widely used to estimate these effects to guide the selection of a policy on management of irrigation return flows. The purpose of this research was to assess the state-of-the-art of hydrosalinity modeling in order to develop a practical management tool for predicting how the salt outflow from irrigated agriculture is affected by various farm management practices. A review of the state-of-the-art of hydrosalinity models identified one of the major gaps in modeling as inadequate understanding and representation of the quantity and quality interrelationships between surface water, drainage water, and groundwater. Most models predict relatively constant levels of salinity over time in surface drains during the irrigation season and an increase in concentration in similar drains at other locations during the nonirrigation season. The study also identified taht a site specific equilibrium threshold conentration (TC) of dissolved solids can be adequately estimated and represented in a model. Salt concentration above the TC would result in precipitation of salts within the soil profile. Higher TC values would, however, exist in the unsaturated soil. Based on these new concepts, salinity in the return flows was modeled as a composite of individual component outflows from the unsaturated zones and the saturated groundwater zone, and represents the interrelationships among surface water, drainage water, and groundwater. The model termed BSAM-SALT was tested using field data from irrigated areas in Grand Valley, Colorado, and the Circleville sub-basin of the Sevier River Basin in Utah. A set of managment runs was made to demonstrate the utility of the model in predicting the salt loading caused by irrigated agriculture in the Grand Valley, Colorado, area

An Energy Accounting Evaluation of Several Alternatives for Hydropower and Geothermal Development

Alternative management strategies for hydropower and geothermal development are myriad. This study does not attempt to evaluate or even summarize the many schemes which are possible. In an era of plentiful natural resources, economic analysis procedures for selecting a particular alternative have been developed which traditionally have tended to optimize on the basis of capital and labor. The approach taken in this study is based on the notion of optimum deployment of finite resources. A legitimate question which this study has attempted to address is: Does the construction of large water management facilities, such as hydropower dams, which involve huge amounts of energy, concrete, and steel, constitute an efficient use of basic resources? An energy accounting analysis technique is proposed, and using this procedure energy resource inputs are examined and compared for specific hydropower dams and geothermal power plants. The technique, though promising, still contains certain problems, and further development is needed in order to establish a consistent and uniform methodology. The energy accounting technique indicates that construction of hydropower facilities is a relatively efficient use of basic energy resources. However, because of large evaporation losses from storage reservoirs, water consumption per unit of power produced tends to be high. An analysis subsequent to the energy accounting approach suggests that combining once-through cooling of thermal power plants with pumped storage hydropower facilities could produce large water savings per unit of generated power. Further study of this configuration is recommended. The energy accounting technique also clearly identifies the high efficiency of geothermal power plants in terms of resource deployment. However, warm water geothermal resources of the type generally available in the intermountain region present formidable problems in utilization. The report proposes a he at exchange r system design which is capable of utilizing warm and highly mineralized waters, and recommends that the design be constructed and tested on a demonstration basis

A Hydrologic Model of the Bear River Basin

As demands upon available water supplies increase, there is an accompanying increase in the need to assess downstream consequences resulting from changes at specific locations within a hydrologic system. The problem is approached in this study by hybrid computer simulation of the hydrologic system. Modeling concepts are based upon the development of basic relationships which describe the various hydrologic processes. Within a system these relationships are linked by the continuity-of-mass priciple which requires a hydrologic balance at all points. Spatial resolution is achieved by considering the modeled areas as a series of subbasins. The time increment adopted for the model is one month, so taht time varying quantities are expressed in terms of mean monthly values. The model is general in nature and in applied to a partifular hydrologic system through a programmed verification procedure whereby model coefficients are evaluated for the particular system. In this study the model was synthesized on a hybrid computer and applied to the Bear River basin of western Wyoming, southern Idaho, and northern Utah. Comparisons between observed and comptued outflow hydrographs for each subbasin are shown. The utility of the model for predicting the effects of various possible water resources management alternatives is demonstrated for the number 1, or Evanston subbasin. The hybrid computer is very efficient for model development, and the verified model can be readily programmed on the all-digital computer

Draft Genome Sequence of a Community-Associated Methicillin- Resistant Panton-Valentine Leukocidin-Positive Staphylococcus aureus Sequence Type 30 Isolate from a Pediatric Patient with a Lung Infection in Brazil

The sequence of methicillin-resistant Staphylococcus aureus strain B6 (sequence type 30 [ST30], spa type t433, staphylococcal chromosomal cassette mec element [SCCmec] type IVc, Panton-Valentine leukocidin [PVL] positive), isolated from a pediatric patient with a lung infection in Niterói, Rio de Janeiro, Brazil, is described here. The draft genome sequence includes a 2.8-Mb chromosome, accompanied by a 20-kb plasmid containing blaZ and two small cryptic plasmids

Functional MRI Assessment of Renal Fibrosis in Rat Models

poster abstractIntroduction Renal fibrosis is a common consequence of chronic kidney diseases which affects a large population. Therefore, it is important to establish imaging based noninvasive biomarkers to monitor the progression or regression of renal fibrosis instead of biopsy. Magnetic resonance imaging (MRI) could provide both high spatial resolution and excellent tissue contrast for visualization of kidney morphology. Moreover, MRI is capable of assessing pseudo perfusion (Df) and perfusion fraction (Pf) with intra-voxel incoherent motion (IVIM) imaging (1), tissue oxygenation with T2* mapping (2), macromolecular composition with T1rho imaging (3) and kidney function (eGFR) with dynamic contrast enhanced (DCE) imaging (4). This study is aimed to evaluate the sensitivity of these MRI techniques to the renal fibrotic changes in a rat model. Methods A total of 4 rats were scanned at early (2-5 days) and late (25-35 days) time points after surgical intervention (unilateral ureteral obstruction to induce renal fibrosis) on a Siemens Tim Trio 3T scanner using an 80mm inner diameter 8-channel rat body coil (RAPID, USA) under a stable anesthetized condition. Axial images of 80mm FOV, 2mm slice thick and sub-millimeter in-place resolution were acquired for different functional MRI techniques with following parameters, respectively: IVIM with10 b-values of 0 - 750 s/mm2. T2*: with 10 TEs of 8 - 66 ms; T1rho: with 9 TSL times of 5 - 80 ms; DCE: with150 dynamic measurements at a temporal resolution of 1.01 s. before and after a 15s injection of 1.1 ml GD-DTPA through rat tail with a power injector. Functional data were processed and analyzed using custom MATLAB programs or analysis tools installed in the MRI console workstation. Results Figure 1 shows an anatomical image of the obstructed (R) and healthy (L) rat kidneys. Figures 2-4 show example T1rho map, IVIM Df map, and T2* map, respectively. Quantitative results based on ROI measurements are summarized in table 1. Changes consistent with the expected progression of fibrosis were observed in the obstructed kidney (R) while the healthy kidney (L) and muscle region remained stable. Figure 5 shows the DCE-MRI images at baseline as well as 45s, 95s and 240s after contrast infusion. The timing and intensity of signal changes are clearly different between two kidneys. Quantitative results of DCE-MRI data and comparison with PET study is reported in a separate abstract. Discussion High quality anatomical and functional images of rat kidney can be obtained on a clinical 3.0T MR scanner with dedicated small animal coils and optimized imaging techniques. The findings suggest that IVIM, T2*, T1rho and DCE can be used to assess and monitor different aspects of physiological changes in kidney fibrosis

Recall intervals for oral health in primary care patients

Publisher Copyright: Copyright © 2020 The Cochrane Collaboration. Published by John Wiley & Sons, Ltd. Copyright: This record is sourced from MEDLINE/PubMed, a database of the U.S. National Library of MedicinePeer reviewedPublisher PD

Energy Impacts of Water Based Recreation

The overall objective of the study reported here was to determine to what extent energy accounting could supplement and/or complement economic benfit/cost analyses of water management projects and to specifically examine the energy impacts of water based recreation. The energy accounting literature was carefully reviewed and an energy accounting methodology applicable to water management was devised. Data pertaining to receation at five reservoirs in Utah were assembled from visitation recoreds and on-site surveys. Energy requirements for site construction, travel to and from the recreation site, and recreation at the site were estimated. It was determined that energy devoted to water based recreation is not inconsequential. As much energy is devoted to recreation at Lake Powell alone as is required for all of production agriculture in Utah. It is suggested that while the models developed in this study could be used with confidence in the preparation of energy impact statements the authors are not persuaded energy accounting provides additional information to water use planners beyong that obtainable from traditional economic analysis

The role of thymosin-?4 in kidney disease

Therapies which modulate inflammation and fibrosis have the potential to reduce the morbidity and mortality associated with chronic kidney disease. A promising avenue may be manipulating thymosin-?4, a naturally-occurring peptide which is the major G-actin sequestering protein in mammalian cells and a regulator of inflammation and fibrosis. Thymosin-?4 is already being tested in clinical trials for heart disease and wound healing. In this editorial, we outline the evidence that thymosin-?4 may also have therapeutic benefit in chronic kidney disease