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Search Results: 1 - 10 of 297611 matches for " J. Markowitz "
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A Review of Introducing Issues with Opposing Viewpoints: Animal Rights. By Lauri S. Friedman. Greenhaven Press: Farmington Hills, MI, USA, 2010; Hardcover, 144 pp; Price:33.58; ISBN: 978-0737749373
Lee J. Markowitz
Animals , 2011, DOI: 10.3390/ani1030256
Abstract: Given the volatile nature of animal rights issues and the extensive array of writings on the topic, one might expect several introductory anthologies to be available. The only anthologies in print, however, are scholarly tomes (listed below) geared towards more advanced readers. Fortunately, Lauri S. Friedman, author of dozens of anthologies on controversial topics such as gun control, national security, terrorism, fast food, sexually transmitted diseases, and many other topics, fills this void well with her volume titled Introducing Issues with Opposing Viewpoints: Animal Rights. She has included articles by influential authors in a diverse range of lay outlets such as The Wall Street Journal, Slate, Guardian, Christianity Today, Food & Wine, among others. Below, I describe the contents of the book, its strengths and weaknesses, and how educators might use the book in classroom settings.
The Conformal Pseudodistance and Null Geodesic Incompleteness
Michael J. Markowitz
Mathematics , 2011,
Abstract: We clarify the relationship between the null geodesic completeness of an Einstein Lorentz manifold and its conformal Kobayashi pseudodistance. We show that an Einstein manifold has at least one incomplete null geodesic if its pseudodistancfe is nontrivial. If its pseudodistance is nondegenerate, all of its null geodesics must be incomplete. Thus an Einstein manifold (M,g) has no complete null geodesic if there is a "physical metric" in the conformal class of g satisfying the null convergence and null generic conditions.
A Suzaku Observation of NGC 4593: Illuminating the Truncated Disk
A. Markowitz,J. N. Reeves
Physics , 2009, DOI: 10.1088/0004-637X/705/1/496
Abstract: We report results from a 2007 Suzaku observation of the Seyfert 1 AGN NGC 4593. The narrow Fe K alpha emission line has a FWHM width ~4000 km/s, indicating emission from >~ 5000 Rg. There is no evidence for a relativistically broadened Fe K line, consistent with the presence of a radiatively efficient outer disk which is truncated or transitions to an interior radiatively inefficient flow. The Suzaku observation caught the source in a low-flux state; compared to a 2002 XMM observation, the hard X-ray flux decreased by 3.6, while the Fe K alpha line intensity and width each roughly halved. Two model-dependent explanations for the changes in Fe line profile are explored. In one, the Fe line width has decreased from ~10000 to ~4000 km/s from 2002 to 2007, suggesting that the thin disk truncation/transition radius has increased from 1000-2000 to >~5000 Rg. However, there are indications from other compact accreting systems that such truncation radii tend to be associated only with accretion rates relative to Eddington much lower than that of NGC 4593. In the second (preferred) model, the line profile in the XMM observation consists of a time-invariant narrow component plus a broad component originating from the inner part of the truncated disk (~300 Rg) which has responded to the drop in continuum flux. The Compton reflection component strength R is ~1.1, consistent with the measured Fe K alpha line total EQW with an Fe abundance 1.7 times solar. The modest soft excess has fallen by a factor of ~20 from 2002 to 2007, ruling out emission from a region 5 lt-yr in size.
Undergraduate nursing textbook coverage of menopause
Jennifer J. Markowitz,Janet S Carpenter
Journal of Nursing Education and Practice , 2012, DOI: 10.5430/jnep.v2n2p18
Abstract: Background: Menopause is a significant part of a woman’s life, it would be expected that nursing students would learn a considerable amount about the changes women go though during this time. The study purpose was to assess the amount of information regarding menopause covered in undergraduate nursing textbooks. Methods: 128 electronic undergraduate nursing textbooks from one publisher were evaluated for menopause content in 11 areas and categorized as having no information (0), some information (1), or complete information (2). The word menopause was searched for each textbook. Results: The number of search hits for the word menopause per textbook was most commonly 1, with 50% having fewer than 7 search hits, and an overall average of 14.02 hits per textbook (SD=15.15, range 1 to 60). The majority of textbooks had no or minimal information about menopause in each category. Conclusions: There is minimal information on menopause in undergraduate nursing textbooks. This suggests that undergraduate nursing students may not be receiving the necessary information to adequately care for menopausal women.
The Song Must Go On: Resilience of the Songbird Vocal Motor Pathway
Barish Poole, Jeffrey E. Markowitz, Timothy J. Gardner
PLOS ONE , 2012, DOI: 10.1371/journal.pone.0038173
Abstract: Stereotyped sequences of neural activity underlie learned vocal behavior in songbirds; principle neurons in the cortical motor nucleus HVC fire in stereotyped sequences with millisecond precision across multiple renditions of a song. The geometry of neural connections underlying these sequences is not known in detail though feed-forward chains are commonly assumed in theoretical models of sequential neural activity. In songbirds, a well-defined cortical-thalamic motor circuit exists but little is known the fine-grain structure of connections within each song nucleus. To examine whether the structure of song is critically dependent on long-range connections within HVC, we bilaterally transected the nucleus along the anterior-posterior axis in normal-hearing and deafened birds. The disruption leads to a slowing of song as well as an increase in acoustic variability. These effects are reversed on a time-scale of days even in deafened birds or in birds that are prevented from singing post-transection. The stereotyped song of zebra finches includes acoustic details that span from milliseconds to seconds–one of the most precise learned behaviors in the animal kingdom. This detailed motor pattern is resilient to disruption of connections at the cortical level, and the details of song variability and duration are maintained by offline homeostasis of the song circuit.
Long-range Order in Canary Song
Jeffrey E. Markowitz,Elizabeth Ivie,Laura Kligler,Timothy J. Gardner
PLOS Computational Biology , 2013, DOI: 10.1371/journal.pcbi.1003052
Abstract: Bird songs range in form from the simple notes of a Chipping Sparrow to the rich performance of the nightingale. Non-adjacent correlations can be found in the syntax of some birdsongs, indicating that the choice of what to sing next is determined not only by the current syllable, but also by previous syllables sung. Here we examine the song of the domesticated canary, a complex singer whose song consists of syllables, grouped into phrases that are arranged in flexible sequences. Phrases are defined by a fundamental time-scale that is independent of the underlying syllable duration. We show that the ordering of phrases is governed by long-range rules: the choice of what phrase to sing next in a given context depends on the history of the song, and for some syllables, highly specific rules produce correlations in song over timescales of up to ten seconds. The neural basis of these long-range correlations may provide insight into how complex behaviors are assembled from more elementary, stereotyped modules.
Gravitational Wave Burst Source Direction Estimation using Time and Amplitude Information
J. Markowitz,M. Zanolin,L. Cadonati,E. Katsavounidis
Physics , 2008, DOI: 10.1103/PhysRevD.78.122003
Abstract: In this article we study two problems that arise when using timing and amplitude estimates from a network of interferometers (IFOs) to evaluate the direction of an incident gravitational wave burst (GWB). First, we discuss an angular bias in the least squares timing-based approach that becomes increasingly relevant for moderate to low signal-to-noise ratios. We show how estimates of the arrival time uncertainties in each detector can be used to correct this bias. We also introduce a stand alone parameter estimation algorithm that can improve the arrival time estimation and provide root-sum-squared strain amplitude (hrss) values for each site. In the second part of the paper we discuss how to resolve the directional ambiguity that arises from observations in three non co-located interferometers between the true source location and its mirror image across the plane containing the detectors. We introduce a new, exact relationship among the hrss values at the three sites that, for sufficiently large signal amplitudes, determines the true source direction regardless of whether or not the signal is linearly polarized. Both the algorithm estimating arrival times, arrival time uncertainties, and hrss values and the directional follow-up can be applied to any set of gravitational wave candidates observed in a network of three non co-located interferometers. As a case study we test the methods on simulated waveforms embedded in simulations of the noise of the LIGO and Virgo detectors at design sensitivity.
How to Peer Review a Hypothesis - Without Killing It
Kenneth Markowitz
Dental Hypotheses , 2010,
Abstract: Dental hypothesis exists to provide the dental community with a forum for free thought and the expression of non-mainstream ideas. It is hoped that the thought provoking ideas expressed in this open access journal will lead to progress in both the scientific and clinical arenas. At first glance the idea of peer reviewing free thought may appear to be impossible. The reviewers and editorial team of Dental hypothesis can reconcile these goals by evaluating contributions for originality, plausibility, importance and clarity of expression. Although a hypothesis may reflect an author's point of view, valuable hypotheses reflect a balanced review of the literature and a reasonable grasp of the complexity of dental issues. Expert reviews are encouraged to challenge authors with alternative points of view while being respectful of the journal's mission to present ideas that many challenge existing paradigms.
The X-ray Power Spectral Density Function and Black Hole Mass Estimate for the Seyfert AGN IC 4329a
A. Markowitz
Physics , 2009, DOI: 10.1088/0004-637X/698/2/1740
Abstract: We present the X-ray broadband power spectral density function (PSD) of the X-ray-luminous Seyfert IC 4329a, constructed from light curves obtained via Rossi X-ray Timing Explorer monitoring and an XMM-Newton observation. Modeling the 3-10 keV PSD using a broken power-law PSD shape, a break in power-law slope is significantly detected at a temporal frequency of 2.5(+2.5,-1.7) * 10^-6 Hz, which corresponds to a PSD break time scale T_b of 4.6(+10.1,-2.3) days. Using the relation between T_b, black hole mass M_BH, and bolometric luminosity as quantified by McHardy and coworkers, we infer a black hole mass estimate of M_BH = 1.3(+1.0,-0.3) * 10^8 solar masses and an accretion rate relative to Eddington of 0.21(+0.06,-0.10) for this source. Our estimate of M_BH is consistent with other estimates, including that derived by the relation between M_BH and stellar velocity dispersion. We also present PSDs for the 10-20 and 20-40 keV bands; they lack sufficient temporal frequency coverage to reveal a significant break, but are consistent with the same PSD shape and break frequency as in the 3-10 keV band.
The X-ray Power Spectral Density Function of the Seyfert Active Galactic Nucleus NGC 7469
Alex Markowitz
Physics , 2010, DOI: 10.1088/0004-637X/724/1/26
Abstract: We present the broadband X-ray power spectral density function (PSD) of the X-ray-luminous Seyfert 1.2 NGC 7469, measured from Rossi X-ray Timing Explorer monitoring data and two XMM-Newton observations. We find significant evidence for a turnover in the 2-10 keV PSD at a temporal frequency of 2.0(+3.0,-0.8)e-6 Hz or 1.0(+3.0,-0.6)e-6 Hz, depending on the exact form of the break (sharply-broken or slowly-bending power-law, respectively). The ``surrogate'' Monte Carlo method of Press et al. (1992) was used to map out the probability distributions of PSD model parameters and obtain reliable uncertainties (68 per cent confidence limits quoted here). The corresponding break time scale of 5.8 (+/- 3.5) days or 11.6(+17.5,-8.7) days, respectively, is consistent with the empirical relation between PSD break time scale, black hole mass and bolometric luminosity of McHardy et al. Compared to the 2-10 keV PSD, the 10-20 keV PSD has a much flatter shape at high temporal frequencies, and no PSD break is significantly detected, suggesting an energy-dependent evolution not unlike that exhibited by several Galactic black hole systems.
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