223 research outputs found
Phase-separation of miscible liquids in a centrifuge
We show that a liquid mixture in the thermodynamically stable homogeneous
phase can undergo a phase-separation transition when rotated at sufficiently
high frequency . This phase-transition is different from the usual case
where two liquids are immiscible or where the slow sedimentation process of one
component (e.g. a polymer) is accelerated due to centrifugation. For a binary
mixture, the main coupling is due to a term ,
where is the difference between the two liquid densities and
the distance from the rotation axis. Below the critical temperature there is a
critical rotation frequency , below which smooth density gradients
occur. When , we find a sharp interface between the low
density liquid close to the center of the centrifuge and a high density liquid
far from the center. These findings may be relevant to various separation
processes and to the control of chemical reactions, in particular their
kinetics.Comment: 6 pages, 3 figure
Experimental Implementation of Remote State Preparation by Nuclear Magnetic Resonance
We have experimentally implemented remote state preparation (RSP) of a qubit
from a hydrogen to a carbon nucleus in molecules of carbon-13 labeled
chloroform CHCl over interatomic distances using liquid-state
nuclear magnetic resonance (NMR) technique. Full RSP of a special ensemble of
qubits, i.e., a qubit chosen from equatorial and polar great circles on a Bloch
sphere with Pati's scheme, was achieved with one cbit communication. Such a RSP
scheme can be generalized to prepare a large number of qubit states and may be
used in other quantum information processing and quantum computing.Comment: 10 pages,5 PS figure
Experimental realization of a highly structured search algorithm
The highly structured search algorithm proposed by Hogg[Phys.Rev.Lett.
80,2473(1998)] is implemented experimentally for the 1-SAT problem in a single
search step by using nuclear magnetic resonance technique with two-qubit
sample. It is the first demonstration of the Hogg's algorithm, and can be
readily extended to solving 1-SAT problem for more qubits in one step if the
appropriate samples possessing more qubits are experimentally feasible.Comment: RevTex, 11 pages + 3 pages of figure
Preparation of pseudo-pure states by line-selective pulses in Nuclear Magnetic Resonance
A new method of preparing the pseudo-pure state of a spin system for quantum
computation in liquid nuclear magnetic resonance (NMR) was put forward and
demonstrated experimentally. Applying appropriately connected line-selective
pulses simultaneously and a field gradient pulse techniques we acquired
straightforwardly all pseudo-pure states for two qubits in a single experiment
much efficiently. The signal intensity with the pseudo-pure state prepared in
this way is the same as that of temporal averaging. Our method is suitable for
the system with arbitrary numbers of qubits. As an example of application, a
highly structured search algorithm----Hogg's algorithm was also performed on
the pseudo-pure state prepared by our method.Comment: RevTEX,10 pages,5 PS figure
Rsp5/Nedd4 is the main ubiquitin ligase that targets cytosolic misfolded proteins following heat stress
The heat-shock response is a complex cellular program that induces major changes in protein translation, folding and degradation to alleviate toxicity caused by protein misfolding. Although heat shock has been widely used to study proteostasis, it remained unclear how misfolded proteins are targeted for proteolysis in these conditions. We found that Rsp5 and its mammalian homologue Nedd4 are important E3 ligases responsible for the increased ubiquitylation induced by heat stress. We determined that Rsp5 ubiquitylates mainly cytosolic misfolded proteins upon heat shock for proteasome degradation. We found that ubiquitylation of heat-induced substrates requires the Hsp40 co-chaperone Ydj1 that is further associated with Rsp5 upon heat shock. In addition, ubiquitylation is also promoted by PY Rsp5-binding motifs found primarily in the structured regions of stress-induced substrates, which can act as heat-induced degrons. Our results support a bipartite recognition mechanism combining direct and chaperone-dependent ubiquitylation of misfolded cytosolic proteins by Rsp5
Rethinking Client Drift in Federated Learning: A Logit Perspective
Federated Learning (FL) enables multiple clients to collaboratively learn in
a distributed way, allowing for privacy protection. However, the real-world
non-IID data will lead to client drift which degrades the performance of FL.
Interestingly, we find that the difference in logits between the local and
global models increases as the model is continuously updated, thus seriously
deteriorating FL performance. This is mainly due to catastrophic forgetting
caused by data heterogeneity between clients. To alleviate this problem, we
propose a new algorithm, named FedCSD, a Class prototype Similarity
Distillation in a federated framework to align the local and global models.
FedCSD does not simply transfer global knowledge to local clients, as an
undertrained global model cannot provide reliable knowledge, i.e., class
similarity information, and its wrong soft labels will mislead the optimization
of local models. Concretely, FedCSD introduces a class prototype similarity
distillation to align the local logits with the refined global logits that are
weighted by the similarity between local logits and the global prototype. To
enhance the quality of global logits, FedCSD adopts an adaptive mask to filter
out the terrible soft labels of the global models, thereby preventing them to
mislead local optimization. Extensive experiments demonstrate the superiority
of our method over the state-of-the-art federated learning approaches in
various heterogeneous settings. The source code will be released.Comment: 11 pages, 7 figure
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