1,208 research outputs found
A Computer Algorithm For Engineering Off-Shell Multiplets With Four Supercharges On The World Sheet
We present an adinkra-based computer algorithm implemented in a Mathematica
code and use it in a limited demonstration of how to engineer off-shell,
arbitrary N-extended world-sheet supermultiplets. Using one of the outputs from
this algorithm, we present evidence for the unexpected discovery of a
previously unknown 8 - 8 representation of N = 2 world sheet supersymmetry. As
well, we uncover a menagerie of (p, q) = (3, 1) world sheet supermultiplets.Comment: 52 pages, 64 figures, LaTeX twice, added note in proof, addition of
comments about gauge invariance for 4D vector & tensor supermultiplet
Universal Markovian reduction of Brownian particle dynamics
Non-Markovian processes can often be turned Markovian by enlarging the set of
variables. Here we show, by an explicit construction, how this can be done for
the dynamics of a Brownian particle obeying the generalized Langevin equation.
Given an arbitrary bath spectral density , we introduce an orthogonal
transformation of the bath variables into effective modes, leading stepwise to
a semi-infinite chain with nearest-neighbor interactions. The transformation is
uniquely determined by and defines a sequence
of residual spectral densities describing the
interaction of the terminal chain mode, at each step, with the remaining bath.
We derive a simple, one-term recurrence relation for this sequence, and show
that its limit is the quasi-Ohmic expression provided by the Rubin model of
dissipation. Numerical calculations show that, irrespective of the details of
, convergence is fast enough to be useful in practice for an effective
Markovian reduction of quantum dissipative dynamics
RNA secondary structure design
We consider the inverse-folding problem for RNA secondary structures: for a
given (pseudo-knot-free) secondary structure find a sequence that has that
structure as its ground state. If such a sequence exists, the structure is
called designable. We implemented a branch-and-bound algorithm that is able to
do an exhaustive search within the sequence space, i.e., gives an exact answer
whether such a sequence exists. The bound required by the branch-and-bound
algorithm are calculated by a dynamic programming algorithm. We consider
different alphabet sizes and an ensemble of random structures, which we want to
design. We find that for two letters almost none of these structures are
designable. The designability improves for the three-letter case, but still a
significant fraction of structures is undesignable. This changes when we look
at the natural four-letter case with two pairs of complementary bases:
undesignable structures are the exception, although they still exist. Finally,
we also study the relation between designability and the algorithmic complexity
of the branch-and-bound algorithm. Within the ensemble of structures, a high
average degree of undesignability is correlated to a long time to prove that a
given structure is (un-)designable. In the four-letter case, where the
designability is high everywhere, the algorithmic complexity is highest in the
region of naturally occurring RNA.Comment: 11 pages, 10 figure
Blue native DIGE as a tool for comparative analyses of protein complexes
Differential gel electrophoresis (DIGE) is based on pre-labeling of different protein fractions and their subsequent co-electrophoresis in a single gel. Cyanine based "CyDye DIGE Fluor minimal dyes" are used for the labeling reaction and 2D IEF/SDS PAGE is the preferential electrophoresis system for protein separation. The DIGE technology allows elimination of inconsistencies based on gel to gel variations and furthermore allows exact quantification of proteins separated by gel electrophoresis. Here we report applications of the DIGE technology in combination with another 2D gel system, Blue native/SDS PAGE. "Blue native DIGE" offers (i) systematic and quantitative comparison of protein complexes of related protein fractions, (ii) structural investigation of protein complexes, (iii) assignment of protein complexes to subcellular fractions like organelles and (iv) electrophoretic mapping of isoforms of subunits of protein complexes with respect to a larger proteome. The potential of "Blue native DIGE" is illustrated by analysis of organellar fractions from the plant Arabidopsis thaliana and the alga Polytomella. Use of the DIGE technology for topological investigations is discussed
Lunar Modular Operations Tool Holster: Space Suit Attachment Quick Release Device
The Embry-Riddle Aeronautical University (ERAU) Spacesuit Utilization of Innovative Technology Laboratory (S.U.I.T. Lab) specializes in spacesuit operations, testing, and analysis with a focus on human performance. The lab promotes undergraduate research and works to involve students in all disciplines. A majority of the students involved with the lab are studying Spaceflight Operations, Aerospace/Mechanical Engineering, or Human Factors. This proposal, created by undergraduate students at ERAU, seeks to describe the capabilities of the Luna Modular Operations Tool Holster (LunaMOTH). LunaMOTH has been designed to enable an astronaut to quickly and easily remove and replace a tool on the spacesuit utility belt during work on the lunar surface. The attachment system is composed of two interlocking portions: the suit-side interface and the tool-side interface. The tool-side interface is a protruding knob on an oblong neck that slides into a slot on the suit-side interface. This is kept in place by the resistance of spring plungers installed in the sides of this slot. The modular system includes a wedge-shaped backplate that further discourages accidental release of the tool, should an additional level of security be desired. To remove a tool from the stowed configuration, the astronaut applies minimal force to lift the neck of the tool-side interface past the plungers. The tool is returned by guiding the tool-side interface into the opening of the suit-side interface and applying downward force to lock them together. LunaMOTH is designed with user mobility and dust tolerance in mind and will assist astronauts in efficiently completing tasks during Extravehicular Activity (EVA) operations on the Moon
Development and test results of a readout chip for the GERDA experiment
This paper describes the F-CSA104 architecture and its measurement results. The F-CSA104 is for γ spectroscopy with Ge detectors. It is a low noise, fully integrated, four channel XFAB 0.6μm CMOS technology ASIC, that has been developed for the GERDA experiment. Each channel contains a charge sensitive preamplifier (CSA) followed by a 11.7MHz differential line driver. It has been particularly designed to operate in liquid argon (T = 87K/-186°C) and to have a measuring sensitivity of 660e- with an ENC of 110e-, after offline filtering with 10μs shaping, when connected to a 30pF load. Special techniques are used to improve the SNR such as a large input PMOS FET, an integrated 500MΩ CSA feedback resistor and a noise degeneration drain resistor
Label-free profiling of white adipose tissue of rats exhibiting high or low levels of intrinsic exercise capacity
Divergent selection has created rat phenotypes of high- and low-capacity runners (HCR and LCR, respectively) that have differences in aerobic capacity and correlated traits such as adiposity. We analyzed visceral adipose tissue of HCR and LCR using label-free high-definition MS (elevated energy) profiling. The running capacity of HCR was ninefold greater than LCR. Proteome profiling encompassed 448 proteins and detected 30 significant (p <0.05; false discovery rate <10%, calculated using q-values) differences. Approximately half of the proteins analyzed were of mitochondrial origin, but there were no significant differences in the abundance of proteins involved in aerobic metabolism. Instead, adipose tissue of LCR rats exhibited greater abundances of proteins associated with adipogenesis (e.g. cathepsin D), ER stress (e.g. 78 kDa glucose response protein), and inflammation (e.g. Ig gamma-2B chain C region). Whereas the abundance antioxidant enzymes such as superoxide dismutase [Cu-Zn] was greater in HCR tissue. Putative adipokines were also detected, in particular protein S100-B, was 431% more abundant in LCR adipose tissue. These findings reveal low running capacity is associated with a pathological profile in visceral adipose tissue proteome despite no detectable differences in mitochondrial protein abundance
Ohio Conservation Plan: Plains gartersnake, Thamnophis radix
This plan outlines strategies and methods used in an ongoing study initiated in 1999 to restore a selfsustaining population of the Plains gartersnake (Thamnophis radix) in Ohio. Restoring a self-sustaining population would require increases in the current population to where the ratios of T. radix to T. sirtalis are approximately 1:1 in multiple locations in Killdeer Plains Wildlife Area (KPWA). This ratio would be similar to what was seen earlier by Reichenbach and Dalrymple (1986) at one site in KPWA.
The plan was developed by a team of enthusiastic conservationists representing, the Division of Wildlife (ODW), the Columbus and Cleveland Zoos, Westerville North High School Field Study Class, Liberty University, Northern Illinois University, and the University of Tennessee. A thorough review of the plan will be made in 2012 with revisions and updates as needed
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