X-Ray Spectra of Z Sources

A simple, physically consistent model has been proposed that seeks to explain in a unified way the X-ray spectra and rapid X-ray variability of the so-called Z sources and other accreting neutron stars in low-mass systems. Here we summarize the results of detailed numerical calculations of the X-ray spectra of the Z sources predicted by this model. Our computations show that in the Z sources, photons are produced primarily by electron cyclotron emission in the neutron star magnetosphere. Comptonization of these photons by the hot central corona and radial inflow produces X-ray spectra, color-color tracks, and countrate variations like those observed in the Z sources.Comment: 6 pages, 2 Postscript figures in 4 files, uses aas2pp4.sty, submitted to ApJ (Letters) 1995 May 3

Some Questions in Connection with State Rate Regulation

There are probably few questions of greater interest, both present and future, than those which concern the relations between corporations performing the so-called public services on the one hand, and their immediate patrons and the general public on the other. These questions relate to the quality and safety of the services rendered, to the rights of all members of the public to receive service without discrimination, and to the charges which may be exacted for those services. To a great extent they involve matters of public policy and economics, rather than those which are strictly legal in nature, while even those questions which have been before the courts are not as yet definitely settled. Among the 1atter is that one which concerns the extent of the power of the states and of the various municipal divisions thereof, under proper delegation of authority, to regulate rates. The existence of this power was established by the decision in the original Granger Cases. That it can not be so exercised as to affect interstate commerce or impair the obligation of a contract was later determined. Within the jurisdiction thus limited, reasonable rates, or rates which permit the earning of a reasonable compensation, may be fixed. To deny the right to earn such compensation would be a deprivation of property without due process of law, and therefore in violation of the fourteenth amendment. But, on the other hand, the public has a right to be served at a reasonable rate, that is, at a rate which bears a reasonable relation to the value of the service rendered. These two rights, to charge a reasonable rate, and to be served at a reasonable price, are conflicting in nature, and it is much easier to state than to reconcile them or to define their limits. The courts have not told us how the reasonable value of a particular service to an individual is to be fixed nor have they laid down any comprehensive rule by which the reasonableness of a particular rate or schedule of rates may be determined

Contactless Remote Induction of Shear Waves in Soft Tissues Using a Transcranial Magnetic Stimulation Device

This study presents the first observation of shear wave induced remotely within soft tissues. It was performed through the combination of a transcranial magnetic stimulation device and a permanent magnet. A physical model based on Maxwell and Navier equations was developed. Experiments were performed on a cryogel phantom and a chicken breast sample. Using an ultrafast ultrasound scanner, shear waves of respective amplitude of 5 and 0.5 micrometers were observed. Experimental and numerical results were in good agreement. This study constitutes the framework of an alternative shear wave elastography method

Complicated lives of college students the educational culture of under-achievers

Titre de l'écran-titre (visionné le 4 oct. 2013)Bibliogr

Comptonization and QPO Origins in Accreting Neutron Star Systems

We develop a simple, time-dependent Comptonization model to probe the origins of spectral variability in accreting neutron star systems. In the model, soft ``seed photons'' are injected into a corona of hot electrons, where they are Compton upscattered before escaping as hard X-rays. The model describes how the hard X-ray spectrum varies when the properties of either the soft photon source or the Comptonizing medium undergo small oscillations. Observations of the resulting spectral modulations can determine whether the variability is due to (i) oscillations in the injection of seed photons, (ii) oscillations in the coronal electron density, or (iii) oscillations in the coronal energy dissipation rate. Identifying the origin of spectral variability should help clarify how the corona operates and its relation to the accretion disk. It will also help in finding the mechanisms underlying the various quasi-periodic oscillations (QPO) observed in the X-ray outputs of many accreting neutron star and black hole systems. As a sample application of our model, we analyze a kilohertz QPO observed in the atoll source 4U~1608-52. We find that the QPO is driven predominantly by an oscillation in the electron density of the Comptonizing gas.Comment: Submitted to MNRAS, 22 pages in latex using AASTeX macros, 5 Postscript figure

Short-term reliability of inflammatory mediators and response to exercise in the heat.

Prospective application of serum cytokines, lipopolysaccharide (LPS), and heat shock proteins (eHSPs) requires reliable measurement of these biomarkers that can signify exercise-induced heat stress in hot conditions. To accomplish this, both short-term (7 day) reliability (at rest, n = 12) and the acute responsiveness of each biomarker to exercise in the heat (pre and post 60-min cycling, 34.5°C and 70% RH, n = 20) were evaluated. Serum was analysed for the concentration of C-reactive protein (CRP), interleukin-6 (IL-6), heat shock protein 72 (eHSP72), immunoglobulin M (IgM) and LPS. Test–retest reliability was determined as the coefficient of variation (CV). Biomarkers with the least short-term within-participant variation were IL-6 (19%, ±20%; CV, ±95% confidence limits (CL)) and LPS (23%, ±13%). Greater variability was observed for IgM, eHSP72 and CRP (CV range 28–38%). IL-6 exhibited the largest increase in response to acute exercise (95%, ±11%, P = < 0.001) and although CRP had a modest CV (12%, ±7%), it increased substantially post-exercise (P = 0.02, ES; 0.78). In contrast, eHSP72 and LPS exhibited trivial changes post-exercise. It appears variation of common inflammatory markers after exercise in the heat is not always discernible from short-term (weekly) variation

Robert Harley and the Great Tory Ministry, 1710-1713

The purpose of this study is to investigate Harley's activities in the years from 1710 to 1713, a short but extremely important period of Harley's life. Emphasis will be placed on Harley as a parliamentary and party leader and on the personal and political connections that made him successful as both

Training Dataset Validation to Protect Machine Learning Models from Data Poisoning

Large language models (LLMs) and other machine learning models are trained on large amounts of curated text data, including both public and private datasets of variable quality. Data collection, cleaning, deduplication, and filtering are performed to build appropriate training datasets. However, such operations cannot protect the trained model against data poisoning (i.e., the intentional corruption of training data) that attempts to manipulate or compromise the behavior of the model. This disclosure describes techniques to improve data security and integrity of the training dataset for LLMs via data validation of a subset (or all) of the data points within the dataset available for training. A data validation policy configuration (specified by the entity that is training and/ or tuning the model) is used to determine a level of confidence of correctness of the data by validating it against different sources. Data that is flagged during validation can be marked/ labeled as less reliable or can be excluded during model training. Model responses can include metadata that indicates a data confidence score for each data point in the response

Complicated lives

"This document is a brief summary of the report entitled Complicated lives"Titre de l'écran-titre (visionné le 4 août 2008).Également disponible en format papier.Bibliogr