1,386 research outputs found
Aircraft control system
An aircraft control system is described which is particularly suited to rotary wing aircraft. Longitudinal acceleration and course rate commands are derived from a manual control stick to control translational velocity of the aircraft along a flight path. In the collective channel the manual controls provide vertical velocity commands. In the yaw channel the manual controls provide sideslip or heading rate commands at high or low airspeeds, respectively. The control system permits pilots to fly along prescribed flight paths in a precise manner with relatively low work load
Fixed-base simulation evaluation of various low-visibility landing systems for helicopters
Fixed base simulation evaluation of one fully automatic and six manual low visibility landing systems for helicopter
TCTP in Development and Cancer
The translationally controlled tumor protein (TCTP) is highly conserved among animal species. It is widely expressed in many different tissues. It is involved in regulating many fundamental processes, such as cell proliferation and growth, apoptosis, pluripotency, and the cell cycle. Hence, it is not surprising that it is essential for normal development and, if misregulated, can lead to cancer. Provided herein is an overview of the diverse functions of TCTP, with a focus on development. Furthermore, we discuss possible ways by which TCTP misregulation or mutation could result in cancer
Quantum phases of hardcore bosons with repulsive dipolar density-density interactions on two-dimensional lattices
We analyse the ground-state quantum phase diagram of hardcore Bosons
interacting with repulsive dipolar potentials. The bosons dynamics is described
by the extended-Bose-Hubbard Hamiltonian on a two-dimensional lattice. The
ground state results from the interplay between the lattice geometry and the
long-range interactions, which we account for by means of a classical spin
mean-field approach limited by the size of the considered unit cells. This
extended classical spin mean-field theory accounts for the long-range
density-density interaction without truncation. We consider three different
lattice geometries: square, honeycomb, and triangular. In the limit of zero
hopping the ground state is always a devil's staircase of solid (gapped)
phases. Such crystalline phases with broken translational symmetry are robust
with respect to finite hopping amplitudes. At intermediate hopping amplitudes,
these gapped phases melt, giving rise to various lattice supersolid phases,
which can have exotic features with multiple sublattice densities. At
sufficiently large hoppings the ground state is a superfluid. The stability of
phases predicted by our approach is gauged by comparison to the known quantum
phase diagrams of the Bose-Hubbard model with nearest-neighbour interactions as
well as quantum Monte Carlo simulations for the dipolar case on the square
lattice. Our results are of immediate relevance for experimental realisations
of self-organised crystalline ordering patterns in analogue quantum simulators,
e.g., with ultracold dipolar atoms in an optical lattice.Comment: 31 pages, 9 figure
Order-by-disorder and long-range interactions in the antiferromagnetic transverse-field Ising model on the triangular lattice -- A perturbative point of view
We study the low-field ground-state (GS) properties of the antiferromagnetic
transverse-field Ising model with long-range interactions (afLRTFIM) on the
triangular lattice. We use the method of perturbative continuous unitary
transformations (pCUT) to derive an effective model for the degenerate GS space
of the antiferromagnetic nearest-neighbour (NN) Ising model on a finite system,
by treating the transverse-field (TF) and the long-range interactions (LRI) as
a perturbation. We determine a level-crossing between the plain stripe phase at
small TF and the clock-ordered phase at intermediate TF at for
, spins in order three perturbation theory. We discuss the
qualitative layout of the quantum phase diagram of the afLRTFIM on the
triangular lattice.Comment: 3 pages, 1 figur
Characteristics and homogeneity of N6-methylation in human genomes.
A novel DNA modification, N-6 methylated deoxyadenosine (m6dA), has recently been discovered in eukaryotic genomes. Despite its low abundance in eukaryotes, m6dA is implicated in human diseases such as cancer. It is therefore important to precisely identify and characterize m6dA in the human genome. Here, we identify m6dA sites at nucleotide level, in different human cells, genome wide. We compare m6dA features between distinct human cells and identify m6dA characteristics in human genomes. Our data demonstrates for the first time that despite low m6dA abundance, the m6dA mark does often occur consistently at the same genomic location within a given human cell type, demonstrating m6dA homogeneity. We further show, for the first time, higher levels of m6dA homogeneity within one chromosome. Most m6dA are found on a single chromosome from a diploid sample, suggesting inheritance. Our transcriptome analysis not only indicates that human genes with m6dA are associated with higher RNA transcript levels but identifies allele-specific gene transcripts showing haplotype-specific m6dA methylation, which are implicated in different biological functions. Our analyses demonstrate the precision and consistency by which the m6dA mark occurs within the human genome, suggesting that m6dA marks are precisely inherited in humans
Systematic Analysis of Crystalline Phases in Bosonic Lattice Models with Algebraically Decaying Density-Density Interactions
We propose a general approach to analyse diagonal ordering patterns in
bosonic lattice models with algebraically decaying density-density interactions
on arbitrary lattices. The key idea is a systematic search for the
energetically best order on all unit cells of the lattice up to a given extent.
Using resummed couplings we evaluate the energy of the ordering patterns in the
thermodynamic limit using finite unit cells. We apply the proposed approach to
the atomic limit of the extended Bose-Hubbard model on the triangular lattice
at fillings and . We investigate the ground-state properties of
the antiferromagnetic long-range Ising model on the triangular lattice and
determine a six-fold degenerate plain-stripe phase to be the ground state for
finite decay exponents. We also probe the classical limit of the
Fendley-Sengupta-Sachdev model describing Rydberg atom arrays. We focus on
arrangements where the atoms are placed on the sites or links of the Kagome
lattice. \changed{Our method provides a general framework to treat cristalline
structures resulting from long-range interactions.Comment: 35 pages, 11 figure
Creating More Integrated Schools in a Segregated System: A Window of Opportunity
The city of Richmond is changing. Over the past decade, an influx of young, white professionals and families has fueled population growth. And increases in the residential population of white families have very slowly translated into increases in the enrollment of white students in Richmond Public Schools (RPS). These shifts come on the heels of decades of intentional division of and disinvestment in majority black urban communities, offering renewed opportunities for neighborhood and school integration, along with a stronger tax base and increases in school funding. But changing demographics also bring challenges. Both the opportunities and challenges have been on full display during the school rezoning process in RPS. This research brief offers important context and content to inform policy decisions that leverage our city’s growing diversity for increased equity and inclusion. In the sections that follow, we share the robust body of research on the benefits of diverse schools, the current state of integration and relevant historical background influencing the need for action, comparable contemporary experiences, common voluntary integration methods--including best and promising practices and lessons learned--and policy and implementation recommendations informed by this information
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