626 research outputs found
Congruent families and invariant tensors
Classical results of Chentsov and Campbell state that -- up to constant
multiples -- the only -tensor field of a statistical model which is
invariant under congruent Markov morphisms is the Fisher metric and the only
invariant -tensor field is the Amari-Chentsov tensor. We generalize this
result for arbitrary degree , showing that any family of -tensors which
is invariant under congruent Markov morphisms is algebraically generated by the
canonical tensor fields defined in an earlier paper
On the behavior of the algebraic transfer
Let Tr_k : ��_2 (⊗ over GL_k) PH_i(B��_k) → Ext^(k,k+i)_A(��_2,��_2) be the algebraic transfer, which is defined by W. Singer as an algebraic version of the geometrical transfer tr_k : π_∗^S((B��_k)_+) → π_∗^S(S^0). It has been shown that the algebraic transfer is highly nontrivial and, more precisely, that Tr_k is an isomorphism for k = 1,2,3. However, Singer showed that Tr_5 is not an epimorphism. In this paper, we prove that Tr_4 does not detect the non zero element g_s ∈ Ext^(4,12·2^s)_A(��_2,��_2) for every s ≥ 1. As a consequence, the localized (Sq^0)^(−1)Tr_4 given by inverting the squaring operation Sq^0 is not an epimorphism. This gives a negative answer to a prediction by Minami
The Force Balance of Electrons During Kinetic Anti-parallel Magnetic Reconnection
Fully kinetic simulations are applied to the study of 2D anti-parallel
reconnection, elucidating the dynamics by which the electron fluid maintains
force balance within both the electron diffusion region (EDR) and the ion
diffusion region (IDR). Inside the IDR, magnetic field-aligned electron
pressure anisotropy ( develops upstream of the
EDR. Compared to previous investigations, the use of modern computer facilities
allows for simulations at the natural proton to electron mass ratio
. In this high--limit the electron dynamics changes
qualitatively, as the electron inflow to the EDR is enhanced and mainly driven
by the anisotropic pressure. Using a coordinate system with the -direction
aligned with the reconnecting magnetic field and the -direction aligned with
the central current layer, it is well-known that for the much studied 2D
laminar anti-parallel and symmetric scenario the reconnection electric field at
the -line must be balanced by the and
off-diagonal electron pressure stress
components. We find that the electron anisotropy upstream of the EDR imposes
large values of within the EDR, and along the
direction of the reconnection -line this stress cancels with the stress of a
previously determined theoretical form for . The
electron frozen-in law is instead broken by pressure tensor gradients related
to the direct heating of the electrons by the reconnection electric field. The
reconnection rate is free to adjust to the value imposed externally by the
plasma dynamics at larger scales.Comment: Submitted to Physics of Plasmas, 11 October 202
Misconceptions of the Deaf: Giving voice to the voiceless
 The Deaf usually do not see themselves as having a disability; however, discourses and social stereotyping continue to portray the Deaf rather negatively. These discourses may lead to misconceptions, prejudice and possibly discrimination. A study was conducted to identify the challenges members of the Deaf community experience accessing quality health care in a small Island state of Australia. Using a qualitative approach, semi-structured interviews and focus groups were conducted with service providers and the Deaf community. Audist discourses of deafness as deficiency, disability and disease remain dominant in contemporary society and are inconsistency with the Deaf community’s own perception of their reality. Despite the dominant constructions of deafness and their affect on the Deaf’s experience of health service provision, many Deaf have developed skills, confidence and resilience to live in the hearing world. The Deaf were pushing back on discourses that construct deafness as a disempowering impairment
Automatic generation of dense non-rigid optical flow
There hardly exists any large-scale datasets with dense optical flow of
non-rigid motion from real-world imagery as of today. The reason lies mainly in
the difficulty of human annotation to generate optical flow ground-truth. To
circumvent the need for human annotation, we propose a framework to
automatically generate optical flow from real-world videos. The method extracts
and matches objects from video frames to compute initial constraints, and
applies a deformation over the objects of interest to obtain dense optical flow
fields. We propose several ways to augment the optical flow variations.
Extensive experimental results show that training on our automatically
generated optical flow outperforms methods that are trained on rigid synthetic
data using FlowNet-S, PWC-Net, and LiteFlowNet. Datasets and algorithms of our
optical flow generation framework is available at
https://github.com/lhoangan/arap_flow.Comment: The paper is under consideration at Computer Vision and Image
Understandin
Singularities and Topology of Meromorphic Functions
We present several aspects of the "topology of meromorphic functions", which
we conceive as a general theory which includes the topology of holomorphic
functions, the topology of pencils on quasi-projective spaces and the topology
of polynomial functions.Comment: 21 pages, 1 figur
- …