Modelling the quiet-time geomagnetic daily variations using observatory data

We present on-going work towards building a global model of the quiet-time geomagnetic daily variation using bservatory data. We select hourly mean data during June 2006 (solar minimum). We fit Fourier series in time, with a fundamental period of 24 hours, to the data at each observatory. We then use global spherical harmonic expansions to separate the daily variation signal, as characterised by the Fourier coefficients in time, into external and induced internal contributions. The models are assessed by comparison with the input data and with Campbell’s Sq model. The robustness of the separation of the field into external and induced internal sources is discussed

Milky Way Tomography with K and M Dwarf Stars: the Vertical Structure of the Galactic Disk

We use the number density distributions of K and M dwarf stars with vertical height from the Galactic disk, determined using observations from the Sloan Digital Sky Survey, to probe the structure of the Milky Way disk across the survey's footprint. Using photometric parallax as a distance estimator we analyze a sample of several million disk stars in matching footprints above and below the Galactic plane, and we determine the location and extent of vertical asymmetries in the number counts in a variety of thin- and thick-disk subsamples in regions of some 200 square degrees within 2 kpc in vertical distance from the Galactic disk. These disk asymmetries present wave-like features as previously observed on other scales and at other distances from the Sun. We additionally explore the scale height of the disk and the implied offset of the Sun from the Galactic plane at different locations, noting that the scale height of the disk can differ significantly when measured using stars only above or only below the plane. Moreover, we compare the shape of the number density distribution in the north for different latitude ranges with a fixed range in longitude and find the shape to be sensitive to the selected latitude window. We explain why this may be indicative of a change in stellar populations in the latitude regions compared, possibly allowing access to the systematic metallicity difference between thin- and thick-disk populations through photometry.Comment: 41 pages, 17 figures, accepted for publication in ApJ; published version [oversight in Fig. 12 fixed

Civil Procedure as a Critical Discussion

This Article develops a model for analyzing legal dispute resolution systems as systems for argumentation. Our model meshes two theories of argument conceived centuries apart: contemporary argumentation theory and classical stasis theory. In this Article, we apply the model to the Federal Rules of Civil Procedure as a proof of concept. Specifically, the model analyzes how the Federal Rules of Civil Procedure function as a staged argumentative critical discussion designed to permit judge and jury to rationally resolve litigants’ differences in a reasonable manner. At a high level, this critical discussion has three phases: a confrontation, an (extended) opening, and a concluding phase. Those phases are the umbrella under which discrete argumentation phases occur at points we call stases. Whenever litigants seek a ruling or judgment, they reach a stasis—a stopping or standing point for arguing procedural points of disagreement. During these stases, the parties make arguments that fall into predictable “commonplace” argument types. Taken together, these stock argument types form a taxonomy of arguments for all civil cases. Our claim that the Federal Rules of Civil Procedure function as a system for argumentation is novel, as is our claim that civil cases breed a taxonomy of argument types. These claims also mark the beginning of a broader project. Starting here with the Federal Rules of Civil Procedure, we embark on a journey that we expect to follow for several years (and which we hope other scholars will join), exploring our model’s application across dispute resolution systems and using it to make normative claims about those systems. From a birds-eye view, this Article also represents a short modern trek in a much longer journey begun by advocates in city states in and near Greece nearly 2500 years ago

MEME08: A global magnetic field model with satellite data weighting

A new data weighting scheme is introduced for satellite geomagnetic survey data. This scheme allows vector samples of the field to be used at all magnetic latitudes and results in an improved lithospheric model, particularly in the auroral regions. Data weights for 20-second spaced satellite samples are derived from two noise estimators for the sample. Firstly the standard deviation along the 20 seconds of satellite track, centred on each sample, is computed as a measure of local magnetic activity. Secondly a larger-scale noise estimator is defined in terms of a ‘local area vector activity’ (LAVA) index for the sample. This is derived from activity estimated from the geographically nearest magnetic observatories to the sample point. Weighting of satellite data by the inverse-sum-of-squares of these noise estimators leads to a robust model of the field (called ‘Model of Earth’s Magnetic Environment 2008, or ‘MEME08’ - to rhyme with ‘beam’) to about spherical harmonic degree 60. In particular we find that vector data may be used at all latitudes and that there is no need to use particularly complex model parameterizations, regularisation, or prior data correction to remove estimates of un-modelled source fields

Improving time-dependent parameters of magnetic field models

An important part of modelling the Earth's magnetic field is to accurately characterise its temporal variation, in particular the secular variation, and secular acceleration. These quantities are sensitive to the data selection and the time-dependent parameterisation and we present modifications to these strategies. When selecting satellite data for magnetic field modelling it is normal practice to use less disturbed data collected when the local time is between certain hours during the night and perhaps additionally when the data are not sunlit. However this approach results in gaps in the temporal data distribution which are likely to compromise the model parameters that depend on time. If the solar zenith angle is also a selection criterion, parameters which depend on location will also be compromised as an annual signal is introduced into the data distribution at high latitudes. Here we strive for a more continuous coverage in time. Rather than eliminating large amounts of data which are normally considered to be too noisy to include in the model, we downweight these data. This builds on work done previously involving small-scale noise

An in vitro evaluation of the efficacy of tedizolid: implications for the treatment of skin and soft tissue infections

Skin and soft tissue infections (SSTI) are among the most commonly occurring infections and evidence suggests that these are increasing world-wide. The aetiology is diverse, but Staphylococcus aureus predominate and these are often resistant to antimicrobials that were previously effective. Tedizolid is a new oxazolidinone-class antibacterial indicated for the treatment of adults with SSTI caused by Gram-positive pathogens, including S. aureus. The aim of this study was to evaluate the in vitro efficacy of tedizolid in comparison to other clinically used antibacterials against antibiotic sensitive- and resistant-staphylococci, grown in planktonic cultures and as biofilms reflecting the growth of the microorganism during episodes of SSTI. Against a panel of 66 clinical staphylococci, sensitivity testing revealed that a lower concentration of tedizolid was required to inhibit the growth of staphylococci compared to linezolid, vancomycin and daptomycin; with the tedizolid MIC being 8-fold (S. aureus) or 4-fold (S. epidermidis) below that obtained for linezolid. In addition, cfr+ linezolid-resistant strains remained fully susceptible to tedizolid. Against S. aureus biofilms, 10×MIC tedizolid was superior or comparable with 10×MIC comparator agents in activity, and superior to 10×MIC linezolid against those formed by S. epidermidis (65 vs. 33% reduction, respectively). Under flow-conditions both oxazolidinones at 10×MIC statistically out-performed vancomycin in their ability to reduce the viable cell count within a S. aureus biofilm with fewer the 12% of cells surviving compared to 63% of cells. In conclusion, tedizolid offers a realistic lower-dose alternative agent to treat staphylococcal SSTI, including infections caused by multi-drug resistant strains

As We Age: Current Considerations About the Elderly and Firearms

In the United States, more than 17 million people over the age of 65 own a firearm. They have the highest rate of suicide by a firearm, and recent data suggest that a disproportionate number apply to carry a concealed weapon. At least one new handgun has been designed and marketed with older people in mind. Memory, thinking, and judgment as well as physical and behavioral competence issues related to an elder\u27s safe operation of a motor vehicle apply to firearms, too. Gun availability can pose a particular risk to those with dementia as well as to their caretakers. The elderly constitute a substantial and rapidly growing population/market segment for whom the public health implications of firearm production, promotion, access, ownership, and use merit consideration

How to Collect your Water Sample and Interpret the Results for the Poultry Analytical Package

Rapidly growing birds may consume up to twice as much water as feed (Scantling and Watkins 2013), which means a plentiful supply of clean water is crucial for poultry health and productivity. To determine the quality of your poultry’s water resources, periodic sampling and analysis is needed. Analyzing water supplies can also be a crucial tool in identifying existing or potential challenges. The Arkansas Water Resources Center (AWRC) in cooperation with the UA Cooperative Extension Service offers several analytical packages to assess the quality of your water resources. This document is intended to provide guidance to poultry producers on collecting water samples for analysis and understanding the “Poultry Water Report Form” provided by the AWRC’s Water Quality Laboratory (Lab). The information contained within this fact sheet should be used as general guidance, and the reader is encouraged to seek advice from Extension specialists regarding the interpretation of individual reports and water testing results that may be of concern