18,504 research outputs found
Radiative transitions involving the (2p2)(3 Pe) metastable autodetaching of H(-)
The absorption coefficient for the free-bound transition H (ls) + e(-)+ h omega yields H(-)(2 sq p,(3)P(e)) is calculated (together with the differential emission rate for the inverse process) using ls - 2s - 2p close coupling continuum wave functions and a Hylleraas bound state wave function. A maximum in the absorption and emission spectra is found to occur at a photon wavelength of 1219.5 A, which is 2 A closer to the Lyman alpha line than predicted by the calculations of Drake, and is in closer agreement with the stellar absorption feature identified by Heap and Stecher. The free-bound absorption process appears to be a significant source of continuous ultraviolet opacity
Passive propellant system
The system utilizes a spherical tank structure A separated into two equal volume compartments by a flat bulkhead B. Each compartment has four similar gallery channel legs located in the principal vehicle axes, ensuring that bulk propellant will contact at least one gallery leg during vehicle maneuvers. The forward compartment gallery channel legs collect propellant and feed it into the aft compartment through communication screens which protrude into the aft compartment. The propellant is then collected by the screened gallery channels in the aft compartment and supplied to the propellant outlet. The invention resides in the independent gallery assembly and screen structure by means of which propellant flow from forward to aft compartments is maintained. Liquid surface tension of the liquid on the screens is used to control liquid flow. The system provides gas-free propellants in low or zero-g environments regardless of axial accelerations and propellant orientation in bulk regions of the vessel
Exact N-vortex solutions to the Ginzburg-Landau equations for kappa=1/sqrt(2)
The N-vortex solutions to the two-dimensional Ginzburg - Landau equations for
the kappa=1/\sqrt(2) parameter are built. The exact solutions are derived for
the vortices with large numbers of the magnetic flux quanta. The size of vortex
core is supposed to be much greater than the magnetic field penetration depth.
In this limiting case the problem is reduced to the determination of vortex
core shape. The corresponding nonlinear boundary problem is solved by means of
the methods of the theory of analytic functions.Comment: 12 pages in RevTex, 1 Postscript figur
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Salmonella Infection After Craniotomy.
Salmonella is an uncommon cause of meningitis, especially after neurosurgery. Here, we present a case of Salmonella meningitis after craniotomy, likely due to physical contact with a snake after surgery, with contiguous spread from the patient's hand to her wound. The purpose of this report is to serve as a reminder that patients undergoing neurosurgery should avoid contact with pets, including snakes and other reptiles, in the postoperative periodĀ and practice good hand hygiene
Extended symmetrical classical electrodynamics
In the present article, we discuss a modification of classical
electrodynamics in which ``ordinary'' point charges are absent. The modified
equations contain additional terms describing the induced charges and currents.
The densities of the induced charges and currents depend on the vector k and
the vectors of the electromagnetic field E and B. It is shown that the vectors
E and B can be defined in terms of two 4-potentials and the components of k are
the components of the 4-tensor of the third rank. The Lagrangian of modified
electrodynamics is defined. The conditions are derived at which only one
4-potential determines the behavior of the electromagnetic field. It is also
shown that static modified electrodynamics can describe the electromagnetic
field in the inner region of the electric monopole. In the outer region of the
electric monopole the electric field is governed by the Maxwell equations. It
follows from boundary conditions at the interface between the inner and outer
regions of the monopole that the vector k has a discrete spectrum. The electric
and magnetic fields, energy and angular momentum of the monopole are found for
different eigenvalues of k
Noticing for Equity to Sustain Multilingual Literacies
This department explores how teachers can sustain studentsā multilingual literacies and reimagine literacy learning across multiple contexts in conversation with researchers, practitioners, and communities
Affective iconic words benefit from additional soundāmeaning integration in the left amygdala
Recent studies have shown that a similarity between sound and meaning of a word (i.e., iconicity) can help more readily access the meaning of that word, but the neural mechanisms underlying this beneficial role of iconicity in semantic processing remain largely unknown. In an fMRI study, we focused on the affective domain and examined whether affective iconic words (e.g., high arousal in both sound and meaning) activate additional brain regions that integrate emotional information from different domains (i.e., sound and meaning). In line with our hypothesis, affective iconic words, compared to their nonāiconic counterparts, elicited additional BOLD responses in the left amygdala known for its role in multimodal representation of emotions. Functional connectivity analyses revealed that the observed amygdalar activity was modulated by an interaction of iconic condition and activations in two hubs representative for processing sound (left superior temporal gyrus) and meaning (left inferior frontal gyrus) of words. These results provide a neural explanation for the facilitative role of iconicity in language processing and indicate that language users are sensitive to the interaction between sound and meaning aspect of words, suggesting the existence of iconicity as a general property of human language
Disparity of superconducting and pseudogap scales in low-Tc Bi-2201 cuprates
We experimentally study transport and intrinsic tunneling characteristics of
a single-layer cuprate Bi(2+x)Sr(2-y)CuO(6+delta) with a low superconducting
critical temperature Tc < 4 K. It is observed that the superconducting energy,
critical field and fluctuation temperature range are scaling down with Tc,
while the corresponding pseudogap characteristics have the same order of
magnitude as for high-Tc cuprates with 20 to 30 times higher Tc. The observed
disparity of the superconducting and pseudogap scales clearly reveals their
different origins.Comment: 5 page
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