14,525 research outputs found
Naturalness, dark matter, and the muon anomalous magnetic moment in supersymmetric extensions of the standard model with a pseudo-Dirac gluino
We study the naturalness, dark matter, and muon anomalous magnetic moment in
the Supersymmetric Standard Models (SSMs) with a pseudo-Dirac gluino (PDGSSMs)
from hybrid and term supersymmetry (SUSY) breakings. To obtain the
observed dark matter relic density and explain the muon anomalous magnetic
moment, we find that the low energy fine-tuning measures are larger than about
30 due to strong constraints from the LUX and PANDAX experiments. Thus, to
study the natural PDGSSMs, we consider multi-component dark matter and then the
relic density of the lighest supersymmetric particle (LSP) neutralino is
smaller than the correct value. We classify our models into six kinds: (i) Case
A is a general case, which has small low energy fine-tuning measure and can
explain the anomalous magnetic moment of the muon; (ii) Case B with the LSP
neutralino and light stau coannihilation; (iii) Case C with Higgs funnel; (iv)
Case D with Higgsino LSP; (v) Case E with light stau coannihilation and
Higgsino LSP; (vi) Case F with Higgs funnel and Higgsino LSP. We study these
Cases in details, and show that our models can be natural and consistent with
the LUX and PANDAX experiments, as well as explain the muon anomalous magnetic
moment. In particular, all these cases except the stau coannihilation can even
have low energy fine-tuning measures around 10.Comment: 19 pages, 18 figure
Functional Bias and Spatial Organization of Genes in Mutational Hot and Cold Regions in the Human Genome
The neutral mutation rate is known to vary widely along human chromosomes,
leading to mutational hot and cold regions. We provide evidence that categories
of functionally-related genes reside preferentially in mutationally hot or cold
regions, the size of which we have measured. Genes in hot regions are biased
toward extra-cellular communication (surface receptors, cell adhesion, immune
response, etc.) while those in cold regions are biased toward essential
cellular processes (gene regulation, RNA processing, protein modification,
etc.). From a selective perspective, this organization of genes could minimize
the mutational load on genes that need to be conserved and allow fast evolution
for genes that must frequently adapt. We also analyze the effect of gene
duplication and chromosomal recombination, which contribute significantly to
these biases for certain categories of hot genes. Overall, our results show
that genes are located non-randomly with respect to hot and cold regions,
offering the possibility that selection acts at the level of gene location in
the human genome.Comment: 17 pages, 6 figures, 2 tables. accepted to PLOS Biology, Feb. 2004
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Entanglement in the anisotropic Heisenberg XYZ model with different Dzyaloshinskii-Moriya interaction and inhomogeneous magnetic field
We investigate the entanglement in a two-qubit Heisenberg XYZ system with
different Dzyaloshinskii-Moriya(DM) interaction and inhomogeneous magnetic
field. It is found that the control parameters (, and )
are remarkably different with the common control parameters (,
and ) in the entanglement and the critical temperature, and these
x-component parameters can increase the entanglement and the critical
temperature more efficiently. Furthermore, we show the properties of these
x-component parameters for the control of entanglement. In the ground state,
increasing (spin-orbit coupling parameter) can decrease the critical
value and increase the entanglement in the revival region, and
adjusting some parameters (increasing and , decreasing and
) can decrease the critical value to enlarge the revival
region. In the thermal state, increasing can increase the revival
region and the entanglement in the revival region (for or ), and
enhance the critical value to make the region of high entanglement
larger. Also, the entanglement and the revival region will increase with the
decrease of (uniform magnetic field). In addition, small
(nonuniform magnetic field) has some similar properties to , and with
the increase of the entanglement also has a revival phenomenon, so that
the entanglement can exist at higher temperature for larger .Comment: 8 pages, 8 figure
VQS: Linking Segmentations to Questions and Answers for Supervised Attention in VQA and Question-Focused Semantic Segmentation
Rich and dense human labeled datasets are among the main enabling factors for
the recent advance on vision-language understanding. Many seemingly distant
annotations (e.g., semantic segmentation and visual question answering (VQA))
are inherently connected in that they reveal different levels and perspectives
of human understandings about the same visual scenes --- and even the same set
of images (e.g., of COCO). The popularity of COCO correlates those annotations
and tasks. Explicitly linking them up may significantly benefit both individual
tasks and the unified vision and language modeling. We present the preliminary
work of linking the instance segmentations provided by COCO to the questions
and answers (QAs) in the VQA dataset, and name the collected links visual
questions and segmentation answers (VQS). They transfer human supervision
between the previously separate tasks, offer more effective leverage to
existing problems, and also open the door for new research problems and models.
We study two applications of the VQS data in this paper: supervised attention
for VQA and a novel question-focused semantic segmentation task. For the
former, we obtain state-of-the-art results on the VQA real multiple-choice task
by simply augmenting the multilayer perceptrons with some attention features
that are learned using the segmentation-QA links as explicit supervision. To
put the latter in perspective, we study two plausible methods and compare them
to an oracle method assuming that the instance segmentations are given at the
test stage.Comment: To appear on ICCV 201
A robot arm simulation with a shared memory multiprocessor machine
A parallel processing scheme for a single chain robot arm is presented for high speed computation on a shared memory multiprocessor. A recursive formulation that is derived from a virtual work form of the d'Alembert equations of motion is utilized for robot arm dynamics. A joint drive system that consists of a motor rotor and gears is included in the arm dynamics model, in order to take into account gyroscopic effects due to the spinning of the rotor. The fine grain parallelism of mechanical and control subsystem models is exploited, based on independent computation associated with bodies, joint drive systems, and controllers. Efficiency and effectiveness of the parallel scheme are demonstrated through simulations of a telerobotic manipulator arm. Two different mechanical subsystem models, i.e., with and without gyroscopic effects, are compared, to show the trade-off between efficiency and accuracy
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