1,605 research outputs found
Grace Paley: 02-18-1982
In an interview recorded February 18, 1982, Grace Paley reads her short story Wants and discusses her beginnings as a writer, her switch from poetry to the short story, writing while raising children, her political activism, and her strong streak of indolence.https://digitalcommons.brockport.edu/writers_videos/1042/thumbnail.jp
Corneoscleral laceration and ocular burns caused by electronic cigarette explosions
PURPOSE: To report cases of acute globe rupture and bilateral corneal burns from electronic cigarette (EC) explosions. METHODS: Case series. RESULTS: We describe a series of patients with corneal injury caused by EC explosions. Both patients suffered bilateral corneal burns and decreased visual acuity, and one patient sustained a unilateral corneoscleral laceration with prolapsed iris tissue and hyphema. A review of the scientific literature revealed no prior reported cases of ocular injury secondary to EC explosions; however, multiple media and government agency articles describe fires and explosions involving ECs, including at least 4 with ocular injuries. CONCLUSIONS: Given these cases and the number of recent media reports, ECs pose a significant public health risk. Users should be warned regarding the possibility of severe injury, including sight-threatening ocular injuries ranging from corneal burns to full-thickness corneoscleral laceration
Conductance Phases in Aharonov-Bohm Ring Quantum Dots
The regimes of growing phases (for electron numbers N~0-8) that pass into
regions of self-returning phases (for N>8), found recently in quantum dot
conductances by the Weizmann group are accounted for by an elementary Green
function formalism, appropriate to an equi-spaced ladder structure (with at
least three rungs) of electronic levels in the quantum dot. The key features of
the theory are physically a dissipation rate that increases linearly with the
level number (and tentatively linked to coupling to longitudinal optical
phonons) and a set of Fano-like meta-stable levels, which disturb the
unitarity, and mathematically the change over of the position of the complex
transmission amplitude-zeros from the upper-half in the complex gap-voltage
plane to the lower half of that plane. The two regimes are identified with
(respectively) the Blaschke-term and the Kramers-Kronig integral term in the
theory of complex variables.Comment: 20 pages, 4 figure
Real time control of EC heating & current drive systems on TCV
The ability to control, in real time, the electron cyclotron heating & current drive systems for the control of MHD instabilities is particularly important for large tokamaks operating at high performance. Several algorithms have been developed and tested on TCV to explore possible control techniques, first in simple experiments to control the plasma current and elongation and subsequently in experiments to control the sawtooth instability and profile parameters. A summary of these experiments are presented in this paper together with the application of the break-in-slope technique as a possible real time calculation of the location of EC deposition
The Late Time Behavior of False Vacuum Decay: Possible Implications for Cosmology and Metastable Inflating States
We describe here how the late time behavior of the decaying states, which is
predicted to deviate from an exponential form, while normally of insignificant
consequence, may have important cosmological implications in the case of false
vacuum decay. It may increase the likelihood of eternal inflation, and may help
explain the likelihood of observing a small vacuum energy at late times, as
well as arguing against decay into a large negative energy (anti-de Sitter
space), vacuum state as has been motivated by some string theory
considerations. Several interesting open questions are raised, including
whether observing the cosmological configuration of a metastable universe can
constrain its inferred lifetime.Comment: 4 pages, submitted to PRL, one reference changed, and changes to
abstract and concluding sentences to stem possible confusions regarding
observation and metastabilit
An anthropometric model to estimate neonatal fat mass using air displacement plethysmography
<p>Abstract</p> <p>Background</p> <p>Current validated neonatal body composition methods are limited/impractical for use outside of a clinical setting because they are labor intensive, time consuming, and require expensive equipment. The purpose of this study was to develop an anthropometric model to estimate neonatal fat mass (kg) using an air displacement plethysmography (PEA POD<sup>® </sup>Infant Body Composition System) as the criterion.</p> <p>Methods</p> <p>A total of 128 healthy term infants, 60 females and 68 males, from a multiethnic cohort were included in the analyses. Gender, race/ethnicity, gestational age, age (in days), anthropometric measurements of weight, length, abdominal circumference, skin-fold thicknesses (triceps, biceps, sub scapular, and thigh), and body composition by PEA POD<sup>® </sup>were collected within 1-3 days of birth. Backward stepwise linear regression was used to determine the model that best predicted neonatal fat mass.</p> <p>Results</p> <p>The statistical model that best predicted neonatal fat mass (kg) was: -0.012 -0.064*gender + 0.024*day of measurement post-delivery -0.150*weight (kg) + 0.055*weight (kg)<sup>2 </sup>+ 0.046*ethnicity + 0.020*sum of three skin-fold thicknesses (triceps, sub scapular, and thigh); R<sup>2 </sup>= 0.81, MSE = 0.08 kg.</p> <p>Conclusions</p> <p>Our anthropometric model explained 81% of the variance in neonatal fat mass. Future studies with a greater variety of neonatal anthropometric measurements may provide equations that explain more of the variance.</p
Self-adjoint Lyapunov variables, temporal ordering and irreversible representations of Schroedinger evolution
In non relativistic quantum mechanics time enters as a parameter in the
Schroedinger equation. However, there are various situations where the need
arises to view time as a dynamical variable. In this paper we consider the
dynamical role of time through the construction of a Lyapunov variable - i.e.,
a self-adjoint quantum observable whose expectation value varies monotonically
as time increases. It is shown, in a constructive way, that a certain class of
models admit a Lyapunov variable and that the existence of a Lyapunov variable
implies the existence of a transformation mapping the original quantum
mechanical problem to an equivalent irreversible representation. In addition,
it is proved that in the irreversible representation there exists a natural
time ordering observable splitting the Hilbert space at each t>0 into past and
future subspaces.Comment: Accepted for publication in JMP. Supercedes arXiv:0710.3604.
Discussion expanded to include the case of Hamiltonians with an infinitely
degenerate spectru
Task-Specific Ionic Liquids for Mars Exploration (Green Chemistry for a Red Planet)
Ionic Liquids (ILs) are organic salts with low melting points that are liquid at or near room temperature. The combinations of available ions and task-specific molecular designability make them suitable for a huge variety of tasks. Because of their low flammability, low vapor pressure, and stability in harsh environments (extreme temperatures, hard vacuum) they are generally much safer and "greener" than conventional chemicals and are thus suitable for a wide range of applications that support NASA exploration goals. This presentation describes several of the ongoing applications that are being developed at MSFC
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