4,013 research outputs found
Optical properties of tissue measured using terahertz pulsed imaging.
The first demonstrations of terahertz imaging in biomedicine were made several years ago, but few data are available on the optical properties of human tissue at terahertz frequencies. A catalogue of these properties has been established to estimate variability and determine the practicality of proposed medical applications in terms of penetration depth, image contrast and reflection at boundaries. A pulsed terahertz imaging system with a useful bandwidth 0.5-2.5 THz was used. Local ethical committee approval was obtained. Transmission measurements were made through tissue slices of thickness 0.08 to 1 mm, including tooth enamel and dentine, cortical bone, skin, adipose tissue and striated muscle. The mean and standard deviation for refractive index and linear attenuation coefficient, both broadband and as a function of frequency, were calculated. The measurements were used in simple models of the transmission, reflection and propagation of terahertz radiation in potential medical applications. Refractive indices ranged from 1.5 ± 0.5 for adipose tissue to 3.06 ± 0.09 for tooth enamel. Significant differences (P<0.05) were found between the broadband refractive indices of a number of tissues. Terahertz radiation is strongly absorbed in tissue so reflection imaging, which has lower penetration requirements than transmission, shows promise for dental or dermatological applications
Speciesistic Veganism: An Anthropocentric Argument
The paper proposes an anthropocentric argument for veganism based on a speciesistic premise that most carnists likely affirm: human flourishing should be promoted. I highlight four areas of human suffering promoted by a carnistic diet: (1) health dangers to workers (both physical and psychological), (2) economic dangers to workers, (3) physical dangers to communities around slaughterhouses, and (4) environmental dangers to communities-at-large. Consequently, one could ignore the well-being of non-human animals and nevertheless recognize significant moral failings in the current standard system of meat production
Effective Connectivity Modeling for fMRI: Six Issues and Possible Solutions Using Linear Dynamic Systems
Analysis of directionally specific or causal interactions between regions in functional magnetic resonance imaging (fMRI) data has proliferated. Here we identify six issues with existing effective connectivity methods that need to be addressed. The issues are discussed within the framework of linear dynamic systems for fMRI (LDSf). The first concerns the use of deterministic models to identify inter-regional effective connectivity. We show that deterministic dynamics are incapable of identifying the trial-to-trial variability typically investigated as the marker of connectivity while stochastic models can capture this variability. The second concerns the simplistic (constant) connectivity modeled by most methods. Connectivity parameters of the LDSf model can vary at the same timescale as the input data. Further, extending LDSf to mixtures of multiple models provides more robust connectivity variation. The third concerns the correct identification of the network itself including the number and anatomical origin of the network nodes. Augmentation of the LDSf state space can identify additional nodes of a network. The fourth concerns the locus of the signal used as a “node” in a network. A novel extension LDSf incorporating sparse canonical correlations can select most relevant voxels from an anatomically defined region based on connectivity. The fifth concerns connection interpretation. Individual parameter differences have received most attention. We present alternative network descriptors of connectivity changes which consider the whole network. The sixth concerns the temporal resolution of fMRI data relative to the timescale of the inter-regional interactions in the brain. LDSf includes an “instantaneous” connection term to capture connectivity occurring at timescales faster than the data resolution. The LDS framework can also be extended to statistically combine fMRI and EEG data. The LDSf framework is a promising foundation for effective connectivity analysis
Membership categorization, culture and norms in action
In this article, we examine the extent to which membership categorization analysis (MCA) can inform an understanding of reasoning within the public domain where morality, policy and cultural politics are visible (Smith and Tatalovich, 2003). Through the examination of three examples, we demonstrate how specific types of category device(s) are a ubiquitous feature of accountable practice in the public domain where morality matters and public policy intersect. Furthermore, we argue that MCA provides a method for analysing the mundane mechanics associated with everyday cultural politics and democratic accountability assembled and presented within news media and broadcast settings
Spitzer Space Telescope observations of the Carina Nebula: The steady march of feedback-driven star formation
We report the first results of imaging the Carina Nebula with Spitzer/IRAC,
providing a catalog of point sources and YSOs based on SED fits. We discuss
several aspects of the extended emission, including dust pillars that result
when a clumpy molecular cloud is shredded by massive star feedback. There are
few "extended green objects" (EGOs) normally taken as signposts of outflow
activity, and none of the HH jets detected optically are seen as EGOs. A
population of "extended red objects" tends to be found around OB stars, some
with clear bow-shocks. These are dusty shocks where stellar winds collide with
flows off nearby clouds. Finally, the relative distributions of O stars and
subclusters of YSOs as compared to dust pillars shows that while some YSOs are
located within pillars, many more stars and YSOs reside just outside pillar
heads. We suggest that pillars are transient phenomena, part of a continuous
outwardly propagating wave of star formation driven by massive star feedback.
As pillars are destroyed, they leave newly formed stars in their wake, which
are then subsumed into the young OB association. Altogether, the current
generation of YSOs shows no strong deviation from a normal IMF. The number of
YSOs suggests a roughly constant star-formation rate over the past 3Myr,
implying that star formation in pillars constitutes an important mechanism to
construct unbound OB associations. Accelerated pillars may give birth to O-type
stars that, after several Myr, could appear to have formed in isolation.Comment: 25 pages, 15 figures, MNRAS accepte
Nurses\u27 Alumnae Association Bulletin - Volume 5 Number 8
Calling All Nurses
Financial Report
Calendar of Events
Lest You Forget!
Attention
Review of the Alumnae Association Meetings
President\u27s Report
Barton Memorial Division
Oxygen Therapy
Welcome, White Haven Alumnae
Clinical Use of Penicillin in Infections of the Ears, Nose and Throat
Address - Graduation of Nurses, 1945
Miscellaneous Items
The Blood that Kills
The Story of Malaria
Program
Prizes - May, 1946
Capping Exercises
The Economic Security Program of the Pennsylvania State Nurses\u27 Association
The Clara Melville Scholarship Fund
Card of Thanks
The Poet\u27s Corner
The Hospital Pharmacy
Jefferson Medical College Hospital School of Nursing Faculty
Jefferson Hospital Gray Lady Unite, A.R.R.
The Volunteer Nurses\u27 Aides Salute Jefferson Nurses
Changes in the Staff at Jefferson Hospital
Red Cross Recruits
Did You Know That
The Pennsylvania Nurse
Medical College News
Magazine and Newspaper Items
Central Dressing Room and Transfusion Unit
Rules Concerning Central Dressing Room
Radios and Electrical Appliances
Attending College
Nurses in Anesthesia
Condolences
Marriages
New Arrivals
Deaths
The Bulletin Committee
Attention, Alumnae
New Addresse
Researching trust in the police and trust in justice: a UK perspective
This paper describes the immediate and more distant origins of a programme of comparative research that is examining cross-national variations in public trust in justice and in the police. The programme is built around a module of the fifth European Social Survey, and evolved from a study funded by the European Commission. The paper describes the conceptual framework within which we are operating – developed in large measure from theories of procedural justice. It reviews some of the methodological issues raised by the use of sample surveys to research issues of public trust in the police, public perceptions of institutional legitimacy and compliance with the law. Finally it gives a flavour of some of the early findings emerging from the programme
Candidate X-ray-Emitting OB Stars in the Carina Nebula Identified Via Infrared Spectral Energy Distributions
We report the results of a new survey of massive, OB stars throughout the
Carina Nebula using the X-ray point source catalog provided by the Chandra
Carina Complex Project (CCCP) in conjunction with infrared (IR) photometry from
the Two Micron All-Sky Survey and the Spitzer Space Telescope Vela--Carina
survey. Mid-IR photometry is relatively unaffected by extinction, hence it
provides strong constraints on the luminosities of OB stars, assuming that
their association with the Carina Nebula, and hence their distance, is
confirmed. We fit model stellar atmospheres to the optical (UBV) and IR
spectral energy distributions (SEDs) of 182 OB stars with known spectral types
and measure the bolometric luminosity and extinction for each star. We find
that the extinction law measured toward the OB stars has two components:
Av=1--1.5 mag produced by foreground dust with a ratio of total-to-selective
absorption Rv=3.1 plus a contribution from local dust with Rv>4.0 in the Carina
molecular clouds that increases as Av increases. Using X-ray emission as a
strong indicator of association with Carina, we identify 94 candidate OB stars
with Lbol\geq10^4 Lsun by fitting their IR SEDs. If the candidate OB stars are
eventually confirmed by follow-up spectroscopic observations, the number of
cataloged OB stars in the Carina Nebula will increase by ~50%. Correcting for
incompleteness due to OB stars falling below the Lbol cutoff or the CCCP
detection limit, these results potentially double the size of the young massive
stellar population.Comment: 19 pages, 8 figures, accepted for the ApJS Special Issue on the
Chandra Carina Complex Project (CCCP), scheduled for publication in May 2011.
All 16 CCCP Special Issue papers, including a version of this article with
high-quality figures, are available at
http://cochise.astro.psu.edu/Carina_public/special_issue.html (through 2011
at least
Observations and asteroseismic analysis of the rapidly pulsating hot B subdwarf PG 0911+456
The principal aim of this project is to determine the structural parameters
of the rapidly pulsating subdwarf B star PG 0911+456 from asteroseismology. Our
work forms part of an ongoing programme to constrain the internal
characteristics of hot B subdwarfs with the long-term goal of differentiating
between the various formation scenarios proposed for these objects. First
comparisons of asteroseismic values with evolutionary theory look promising,
however it is clear that more targets are needed for meaningful statistics to
be derived. The observational pulsation periods of PG 0911+456 were extracted
from rapid time-series photometry using standard Fourier analysis techniques.
Supplemented by spectroscopic estimates of the star's mean atmospheric
parameters, they were used as a basis for the "forward modelling" approach in
asteroseismology. The latter culminates in the identification of one or more
"optimal" models that can accurately reproduce the observed period spectrum.
This naturally leads to an identification of the oscillations detected in terms
of degree l and radial order k, and infers the structural parameters of the
target. From the photometry it was possible to extract 7 independent pulsation
periods in the 150-200 s range with amplitudes between 0.05 and 0.8 % of the
star's mean brightness. An asteroseismic search of parameter space identified
several models that matched the observed properties of PG 0911+456 well, one of
which was isolated as the "optimal" model on the basis of spectroscopic and
mode identification considerations. All the observed pulsations are identified
with low-order acoustic modes with degree indices l=0,1,2 and 4, and match the
computed periods with a dispersion of only ~0.26 %.Comment: accepted for publication in A&A, 14 pages, 13 figure
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