3,508 research outputs found
BIOTECHNOLOGY--DIVERSIFICATION, AND THE FOOD INDUSTRY
Research and Development/Tech Change/Emerging Technologies,
Small digital recording head has parallel bit channels, minimizes cross talk
A small digital recording head consists of closely spaced parallel wires, imbedded in a ferrite block to concentrate the magnetic flux. Parallel-recorded information bits are converted into serial bits on moving magnetic tape and cross talk is suppressed
Finite-size effects on a lattice calculation
We study in this paper the finite-size effects of a non-periodic lattice on a
lattice calculation. To this end we use a finite lattice equipped with a
central difference derivative with homogeneous boundary conditions to calculate
the bosonic mass associated to the Schwinger model. We found that the
homogeneous boundary conditions produce absence of fermion doubling and chiral
invariance, but we also found that in the continuum limit this lattice model
does not yield the correct value of the boson mass as other models do. We
discuss the reasons for this and, as a result, the matrix which cause the
fermion doubling problem is identified.Comment: 8 pages, no figures, extended version, five references adde
Vista/F-16 Multi-Axis Thrust Vectoring (MATV) control law design and evaluation
For the Multi-Axis Thrust Vectoring (MATV) program, a new control law was developed using multi-axis thrust vectoring to augment the aircraft's aerodynamic control power to provide maneuverability above the normal F-16 angle of attack limit. The control law architecture was developed using Lockheed Fort Worth's offline and piloted simulation capabilities. The final flight control laws were used in flight test to demonstrate tactical benefits gained by using thrust vectoring in air-to-air combat. Differences between the simulator aerodynamics data base and the actual aircraft aerodynamics led to significantly different lateral-directional flying qualities during the flight test program than those identified during piloted simulation. A 'dial-a-gain' flight test control law update was performed in the middle of the flight test program. This approach allowed for inflight optimization of the aircraft's flying qualities. While this approach is not preferred over updating the simulator aerodynamic data base and then updating the control laws, the final selected gain set did provide adequate lateral-directional flying qualities over the MATV flight envelope. The resulting handling qualities and the departure resistance of the aircraft allowed the 422nd_squadron pilots to focus entirely on evaluating the aircraft's tactical utility
ERTS-1 applications to Minnesota land use mapping
Land use class definitions that can be operationally employed with ERTS-1 imagery are being developed with the cooperation of personnel from several state, regional, and federal agencies with land management responsibilities within the state and the University of Minnesota. Investigations of urban, extractive, forest, and wetlands areas indicate that it is feasible to subdivide each of these classes into several sub-classes with the use of ERTS-1 images from one or more time periods
The Vacuum in Light-Cone Field Theory
This is an overview of the problem of the vacuum in light-cone field theory,
stressing its close connection to other puzzles regarding light-cone
quantization. I explain the sense in which the light-cone vacuum is
``trivial,'' and describe a way of setting up a quantum field theory on null
planes so that it is equivalent to the usual equal-time formulation. This
construction is quite helpful in resolving the puzzling aspects of the
light-cone formalism. It furthermore allows the extraction of effective
Hamiltonians that incorporate vacuum physics, but that act in a Hilbert space
in which the vacuum state is simple. The discussion is fairly informal, and
focuses mainly on the conceptual issues. [Talk presented at {\sc Orbis
Scientiae 1996}, Miami Beach, FL, January 25--28, 1996. To appear in the
proceedings.]Comment: 20 pages, RevTeX, 4 Postscript figures. Minor typos correcte
Pathfinder cells provide a novel therapeutic intervention for acute kidney injury
Pathfinder cells (PCs) are a novel class of adult-derived cells that facilitate functional repair of host tissue. We used rat PCs to demonstrate that they enable the functional mitigation of ischemia reperfusion (I/R) injury in a mouse model of renal damage. Female C57BL/6 mice were subjected to 30 min of renal ischemia and treated with intravenous (i.v.) injection of saline (control) or male rat pancreas-derived PCs in blinded experimentation. Kidney function was assessed 14 days after treatment by measuring serum creatinine (SC) levels. Kidney tissue was assessed by immunohistochemistry (IHC) for markers of cellular damage, proliferation, and senescence (TUNEL, Ki67, p16ink4a, p21). Fluorescence in situ hybridization (FISH) was performed to determine the presence of any rat (i.e., pathfinder) cells in the mouse tissue. PC-treated animals demonstrated superior renal function at day 14 post-I/R, in comparison to saline-treated controls, as measured by SC levels (0.13 mg/dL vs. 0.23 mg/dL, p<0.001). PC-treated kidney tissue expressed significantly lower levels of p16ink4a in comparison to the control group (p=0.009). FISH analysis demonstrated that the overwhelming majority of repaired kidney tissue was mouse in origin. Rat PCs were only detected at a frequency of 0.02%. These data confirm that PCs have the ability to mitigate functional damage to kidney tissue following I/R injury. Kidneys of PC-treated animals showed evidence of improved function and reduced expression of damage markers. The PCs appear to act in a paracrine fashion, stimulating the host tissue to recover functionally, rather than by differentiating into renal cells. This study demonstrates that pancreatic-derived PCs from the adult rat can enable functional repair of renal damage in mice. It validates the use of PCs to regenerate damaged tissues and also offers a novel therapeutic intervention for repair of solid organ damage in situ
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Dynamic MAIT cell response with progressively enhanced innateness during acute HIV-1 infection.
Mucosa-associated invariant T (MAIT) cell loss in chronic HIV-1 infection is a significant insult to antimicrobial immune defenses. Here we investigate the response of MAIT cells during acute HIV-1 infection utilizing the RV217 cohort with paired longitudinal pre- and post-infection samples. MAIT cells are activated and expand in blood and mucosa coincident with peak HIV-1 viremia, in a manner associated with emerging microbial translocation. This is followed by a phase with elevated function as viral replication is controlled to a set-point level, and later by their functional decline at the onset of chronic infection. Interestingly, enhanced innate-like pathways and characteristics develop progressively in MAIT cells during infection, in parallel with TCR repertoire alterations. These findings delineate the dynamic MAIT cell response to acute HIV-1 infection, and show how the MAIT compartment initially responds and expands with enhanced function, followed by progressive reprogramming away from TCR-dependent antibacterial responses towards innate-like functionality
A Density Matrix Renormalization Group Approach to an Asymptotically Free Model with Bound States
We apply the DMRG method to the 2 dimensional delta function potential which
is a simple quantum mechanical model with asymptotic freedom and formation of
bound states. The system block and the environment block of the DMRG contain
the low energy and high energy degrees of freedom, respectively. The ground
state energy and the lowest excited states are obtained with very high
accuracy. We compare the DMRG method with the Similarity RG method and propose
its generalization to field theoretical models in high energy physics.Comment: REVTEX file, 4 pages, 1 Table, 3 eps Figures. Explanation on the
extension to many-body QFT problems added, 3 new references and some minor
changes. New forma
Towards Solving QCD in Light-Cone Quantization -- On the Spectrum of the Transverse Zero Modes for SU(2)
The formalism for a non-abelian pure gauge theory in (2+1) dimensions has
recently been derived within Discretized Light-Cone Quantization, restricting
to the lowest {\it transverse} momentum gluons. It is argued why this model can
be a paradigm for full QCD. The physical vacuum becomes non-trivial even in
light-cone quantization. The approach is brought here to tractable form by
suppressing by hand both the dynamical gauge and the constraint zero mode, and
by performing a Tamm-Dancoff type Fock-space truncation. Within that model the
Hamiltonian is diagonalized numerically, yielding mass spectra and
wavefunctions of the glue-ball states. We find that only color singlets have a
stable and discrete bound state spectrum. The connection with confinement is
discussed. The structure function of the gluons has a shape like . The existence of the continuum limit is verified by deriving a
coupled set of integral equations.Comment: 1 Latex file & 9 Postscript files; tarred, compressed and uuencode
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