1,801 research outputs found
Mode Bifurcation and Fold Points of Complex Dispersion Curves for the Metamaterial Goubau Line
In this paper the complex dispersion curves of the four lowest-order
transverse magnetic modes of a dielectric Goubau line () are
compared with those of a dispersive metamaterial Goubau line. The vastly
different dispersion curve structure for the metamaterial Goubau line is
characterized by unusual features such as mode bifurcation, complex fold
points, both proper and improper complex modes, and merging of complex and real
modes
Differential processing of nociceptive input within upper limb muscles
The cutaneous silent period is an inhibitory evoked response that demonstrates a wide variety of responses in muscles of the human upper limb. Classically, the cutaneous silent period results in a characteristic muscle pattern of extensor inhibition and flexor facilitation within the upper limb, in the presence of nociceptive input. The aims of the current study were: 1) to primarily investigate the presence and characteristics of the cutaneous silent period response across multiple extensor and flexor muscles of the upper limb, and 2) to secondarily investigate the influence of stimulation site on this nociceptive reflex response. It was hypothesized that the cutaneous silent period would be present in all muscles, regardless of role (flexion/extension) or the stimulation site. Twenty-two healthy, university-age adults (14 males; 8 females; 23 ± 5 yrs) participated in the study. Testing consisted of three different stimulation sites (Digit II, V, and II+III nociceptive stimulation) during a low intensity, sustained muscle contraction, in which, 7 upper limb muscles were monitored via surface EMG recording electrodes. Distal muscles of the upper limb presented with the earliest reflex onset times, longest reflex duration, and lowest level of EMG suppression when compared to the more proximal muscles, regardless of extensor/flexor role. Additionally, the greatest overall inhibitory influence was expressed within the distal muscles. In conclusion, the present study provides a new level of refinement within the current understanding of the spinal organization associated with nociceptive input processing and the associated motor control of the upper limb. Subsequently, these results have further implications on the impact of nociception on supraspinal processing
Generation of scalar-tensor gravity effects in equilibrium state boson stars
Boson stars in zero-, one-, and two-node equilibrium states are modeled
numerically within the framework of Scalar-Tensor Gravity. The complex scalar
field is taken to be both massive and self-interacting. Configurations are
formed in the case of a linear gravitational scalar coupling (the Brans-Dicke
case) and a quadratic coupling which has been used previously in a cosmological
context. The coupling parameters and asymptotic value for the gravitational
scalar field are chosen so that the known observational constraints on
Scalar-Tensor Gravity are satisfied. It is found that the constraints are so
restrictive that the field equations of General Relativity and Scalar-Tensor
gravity yield virtually identical solutions. We then use catastrophe theory to
determine the dynamically stable configurations. It is found that the maximum
mass allowed for a stable state in Scalar-Tensor gravity in the present
cosmological era is essentially unchanged from that of General Relativity. We
also construct boson star configurations appropriate to earlier cosmological
eras and find that the maximum mass for stable states is smaller than that
predicted by General Relativity, and the more so for earlier eras. However, our
results also show that if the cosmological era is early enough then only states
with positive binding energy can be constructed.Comment: 20 pages, RevTeX, 11 figures, to appear in Class. Quantum Grav.,
comments added, refs update
An analysis of the requisitioning process for DOD standard stock material at the Naval Postgraduate School, Monterey, California.
http://archive.org/details/analysisofrequis00pos
Social games in a social network
We study an evolutionary version of the Prisoner's Dilemma game, played by
agents placed in a small-world network. Agents are able to change their
strategy, imitating that of the most successful neighbor. We observe that
different topologies, ranging from regular lattices to random graphs, produce a
variety of emergent behaviors. This is a contribution towards the study of
social phenomena and transitions governed by the topology of the community
CD4+ cytolytic effectors are inefficient in the clearance of Listeria monocytogenes
Cytotoxic T lymphocytes (CTL) recognize and lyse target cells through the interaction of the T-cell receptor complex with the class I or class II major histocompatibility complex (MHC). The production of class I-restricted CTL has been shown to be critical to the elimination of specific pathogens including . However, the function of class II-restricted CTL in the clearance of intracellular pathogens is poorly understood. H-2β-microglobulin-deficient mice (βM−/−) are not able to produce CD8 CTL in response to infection with . We used this model to evaluate the efficacy of class II-restricted CTL, in the absence of a class I-restricted response, during a primary infection with . We demonstrate that, despite their effectiveness in adoptive transfer of protection, -specific CD4 class II-restricted cytotoxic lymphocytes are ineffective in decreasing titres of in the spleen after an established infection. In βM−/− mice, persistence of in the spleen was found preferentially in class II-negative cells. Surprisingly, class I-restricted CTL from C57BL/6 mice were capable of decreasing bacterial titres during an established infection even in the absence of detectable class I on the surface of cells from βM−/− mice. These data strongly suggest that, in the absence of a class I-restricted response, pathogens that elicit a class II-restricted cytotoxic response may escape prompt eradication by the immune system
POI6 WOMEN TREATED WITH MONTHLY IBANDRONATE DEMONSTRATE IMPROVED PERSISTENCE VERSUS WEEKLY BISPHOSPHONATES
Pulsive feedback control for stabilizing unstable periodic orbits in a nonlinear oscillator with a non-symmetric potential
We examine a strange chaotic attractor and its unstable periodic orbits in
case of one degree of freedom nonlinear oscillator with non symmetric
potential. We propose an efficient method of chaos control stabilizing these
orbits by a pulsive feedback technique. Discrete set of pulses enable us to
transfer the system from one periodic state to another.Comment: 11 pages, 4 figure
Context and strategy for local housing initiatives : the Boston Linkage Program
Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Urban Studies and Planning, 1991.Includes bibliographical references (leaves 86-90).by Paul R. Poston.M.S
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