2,036 research outputs found
Processing of signals from an ion-elective electrode array by a neural network
Neural network software is described for processing the signals of arrays of ion-selective electrodes. The performance of the software was tested in the simultaneous determination of calcium and copper(II) ions in binary mixtures of copper(II) nitrate and calcium chloride and the simultaneous determination of potassium, calcium, nitrate and chloride in mixtures of potassium and calcium chlorides and ammonium nitrate. The measurements for the Ca2+/Cu2+ determinations were done with a pH-glass electrode and calcium and copper ion-selective electrodes; results were accurate to ±8%. For the K+/Ca2+NO−3/Cl− determinations, the measurements were made with the relevant ion-selective electrodes and a glass electrode; the mean relative error was ±6%, and for the worst cases the error did not exceed 20%
Constraints on the Heating of High Temperature Active Region Loops: Observations from Hinode and SDO
We present observations of high temperature emission in the core of a solar
active region using instruments on Hinode and SDO. These multi-instrument
observations allow us to determine the distribution of plasma temperatures and
follow the evolution of emission at different temperatures. We find that at the
apex of the high temperature loops the emission measure distribution is
strongly peaked near 4 MK and falls off sharply at both higher and lower
temperatures. Perhaps most significantly, the emission measure at 0.5 MK is
reduced by more than two orders of magnitude from the peak at 4 MK. We also
find that the temporal evolution in broad-band soft X-ray images is relatively
constant over about 6 hours of observing. Observations in the cooler SDO/AIA
bandpasses generally do not show cooling loops in the core of the active
region, consistent with the steady emission observed at high temperatures.
These observations suggest that the high temperature loops observed in the core
of an active region are close to equilibrium. We find that it is possible to
reproduce the relative intensities of high temperature emission lines with a
simple, high-frequency heating scenario where heating events occur on time
scales much less than a cooling time. In contrast, low-frequency heating
scenarios, which are commonly invoked to describe nanoflare models of coronal
heating, do not reproduce the relative intensities of high temperature emission
lines and predict low-temperature emission that is approximately an order of
magnitude too large. We also present an initial look at images from the SDO/AIA
94 A channel, which is sensitive to Fe XVIII.Comment: Movies are available at
http://tcrb.nrl.navy.mil/~hwarren/temp/papers/active_region_core/ Paper has
been refereed and revise
An MLSA-based online scheme for the rapid identification of Stenotrophomonas isolates
An online scheme to assign Stenotrophomonas isolates to genomic groups was developed using the multilocus sequence analysis (MLSA), which is based on the DNA sequencing of selected fragments of the housekeeping genes ATP synthase alpha subunit (atpA), the recombination repair protein (recA), the RNA polymerase alpha subunit (rpoA) and the excision repair beta subunit (uvrB). This MLSA-based scheme was validated using eight of the 10 Stenotrophomonas species that have been previously described. The environmental and nosocomial Stenotrophomonas strains were characterised using MLSA, 16S rRNA sequencing and DNA-DNA hybridisation (DDH) analyses. Strains of the same species were found to have greater than 95% concatenated sequence similarity and specific strains formed cohesive readily recognisable phylogenetic groups. Therefore, MLSA appeared to be an effective alternative methodology to amplified fragment length polymorphism fingerprint and DDH techniques. Strains of Stenotrophomonas can be readily assigned through the open database resource that was developed in the current study (www.steno.lncc.br/)
Modeling Bond Yields in Finance and Macroeconomics
From a macroeconomic perspective, the short-term interest rate is a policy instrument under the direct control of the central bank. From a finance perspective, long rates are risk-adjusted averages of expected future short rates. Thus, as illustrated by much recent research, a joint macro-finance modeling strategy will provide the most comprehensive understanding of the term structure of interest rates. We discuss various questions that arise in this research, and we also present a new examination of the relationship between two prominent dynamic, latent factor models in this literature: the Nelson-Siegel and affne no-arbitrage term structure models.
Zygmunt Bauman’s Ethical Warnings in the Area of Economics. The Third Millennium’s Perspective
Zygmunt Bauman is not only a sociologist and philosopher reputable in the world
of science, he is also a father figure for people interested in the phenomenon of
globalization. Bauman investigates how current economic and political changes
influence the lives of particular societies. It was important to underline that also
economists can make use of Bauman’s ideas but with a few reservations That is
why the following crucial areas were proposed relating to economic aspects: the
meaning of consumptionism and wastage; global inequalities; the reasons and
consequences of the global economic crisis, and some heterodox matters such as
happiness, welfare, and well-being, all of which can be helpful in understanding
the multidimensional globalization process
Towards a Quantitative Comparison of Magnetic Field Extrapolations and Observed Coronal Loops
It is widely believed that loops observed in the solar atmosphere trace out
magnetic field lines. However, the degree to which magnetic field
extrapolations yield field lines that actually do follow loops has yet to be
studied systematically. In this paper we apply three different extrapolation
techniques - a simple potential model, a NLFF model based on photospheric
vector data, and a NLFF model based on forward fitting magnetic sources with
vertical currents - to 15 active regions that span a wide range of magnetic
conditions. We use a distance metric to assess how well each of these models is
able to match field lines to the 12,202 loops traced in coronal images. These
distances are typically 1-2". We also compute the misalignment angle between
each traced loop and the local magnetic field vector, and find values of
5-12. We find that the NLFF models generally outperform the potential
extrapolation on these metrics, although the differences between the different
extrapolations are relatively small. The methodology that we employ for this
study suggests a number of ways that both the extrapolations and loop
identification can be improved.Comment: Accepted for publication in Ap
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