56,960 research outputs found
Reciprocatory magnetic reconnection in a coronal bright point
Coronal bright points (CBPs) are small-scale and long-duration brightenings
in the lower solar corona. They are often explained in terms of magnetic
reconnection. We aim to study the sub-structures of a CBP and clarify the
relationship among the brightenings of different patches inside the CBP. The
event was observed by the X-ray Telescope (XRT) aboard the Hinode spacecraft on
2009 August 2223. The CBP showed repetitive brightenings (or CBP flashes).
During each of the two successive CBP flashes, i.e., weak and strong flashes
which are separated by 2 hr, the XRT images revealed that the CBP was
composed of two chambers, i.e., patches A and B. During the weak flash, patch A
brightened first, and patch B brightened 2 min later. During the
transition, the right leg of a large-scale coronal loop drifted from the right
side of the CBP to the left side. During the strong flash, patch B brightened
first, and patch A brightened 2 min later. During the transition, the
right leg of the large-scale coronal loop drifted from the left side of the CBP
to the right side. In each flash, the rapid change of the connectivity of the
large-scale coronal loop is strongly suggestive of the interchange
reconnection. For the first time we found reciprocatory reconnection in the
CBP, i.e., reconnected loops in the outflow region of the first reconnection
process serve as the inflow of the second reconnection process.Comment: 13 pages, 8 figure
Recommended from our members
Promoting tau secretion and propagation by hyperactive p300/CBP via autophagy-lysosomal pathway in tauopathy.
BackgroundThe trans-neuronal propagation of tau has been implicated in the progression of tau-mediated neurodegeneration. There is critical knowledge gap in understanding how tau is released and transmitted, and how that is dysregulated in diseases. Previously, we reported that lysine acetyltransferase p300/CBP acetylates tau and regulates its degradation and toxicity. However, whether p300/CBP is involved in regulation of tau secretion and propagation is unknown.MethodWe investigated the relationship between p300/CBP activity, the autophagy-lysosomal pathway (ALP) and tau secretion in mouse models of tauopathy and in cultured rodent and human neurons. Through a high-through-put compound screen, we identified a new p300 inhibitor that promotes autophagic flux and reduces tau secretion. Using fibril-induced tau spreading models in vitro and in vivo, we examined how p300/CBP regulates tau propagation.ResultsIncreased p300/CBP activity was associated with aberrant accumulation of ALP markers in a tau transgenic mouse model. p300/CBP hyperactivation blocked autophagic flux and increased tau secretion in neurons. Conversely, inhibiting p300/CBP promoted autophagic flux, reduced tau secretion, and reduced tau propagation in fibril-induced tau spreading models in vitro and in vivo.ConclusionsWe report that p300/CBP, a lysine acetyltransferase aberrantly activated in tauopathies, causes impairment in ALP, leading to excess tau secretion. This effect, together with increased intracellular tau accumulation, contributes to enhanced spreading of tau. Our findings suggest that inhibition of p300/CBP as a novel approach to correct ALP dysfunction and block disease progression in tauopathy
A Crevice on the Crane Beach: Finite-Degree Predicates
First-order logic (FO) over words is shown to be equiexpressive with FO
equipped with a restricted set of numerical predicates, namely the order, a
binary predicate MSB, and the finite-degree predicates: FO[Arb] = FO[<,
MSB, Fin].
The Crane Beach Property (CBP), introduced more than a decade ago, is true of
a logic if all the expressible languages admitting a neutral letter are
regular.
Although it is known that FO[Arb] does not have the CBP, it is shown here
that the (strong form of the) CBP holds for both FO[<, Fin] and FO[<, MSB].
Thus FO[<, Fin] exhibits a form of locality and the CBP, and can still express
a wide variety of languages, while being one simple predicate away from the
expressive power of FO[Arb]. The counting ability of FO[<, Fin] is studied as
an application.Comment: Submitte
On the canonical base property
We give an example of a finite rank, in fact aleph-1 categorical theory where
the CBP (canonical base property) does not hold. We include a "group-like"
example. We also prove, in a finite Morley rank context, if all definable
Galois groups are "rigid" then the theory has the CBP (in a strong sense).Comment: 15 page
Overestimation in the Traditional GARCH Model During Jump Periods
The traditional continuous and smooth models, like the GARCH model, may fail to capture extreme returns volatility. Therefore, this study applies the bivariate poisson (CBP)-GARCH model to study jump dynamics in price volatility of crude oil and heating oil during the past 20 years. The empirical results indicate that the variance and covariance of the GARCH and CBP-GARCH models were found to be similar in low jump intensity periods and to diverge during jump events. Significant overestimations occur during high jump time periods in the GARCH model because of assumptions of continuity, and easily leading to excessive hedging and overly measuring risk. Nevertheless, in the CBP-GARCH model, the specific shocks are assumed to be independent of normal volatility and to reduce the persistence of abnormal volatility. Therefore, the CBP-GARCH model is appropriate and necessary in high volatility markets.Jumps Overestimation Volatility CBP-GARCH model
National Evaluation of the Capacity Building Programme in English Local Government: Overall Final Report
This report is one of a series of outputs from the National Evaluation of the Capacity Building Programme for local government in England (CBP), undertaken by a team of researchers at the Policy Research Institute (PRI) at Leeds Metropolitan University and the Cities Research Unit at the University of West of England. This report summarises the findings from all four key strands of the evaluation. Because of the difficulties associated with quantifying the capacity of local authorities, much less the sector, in relation to the dynamic roles and objectives that they pursue, the report focuses on what has worked, why and in what circumstances, rather than providing a definitive assessment of the extent of change of capacity building enabled by the CBP. The CBP was launched in 2003 as a joint Department for Communities and Local Government/Local Government Association (LGA) initiative to support capacity building and improvement activities within local authorities in England. The CBP has supported four main streams of improvement and capacity building activity in local authorities (see Section 1.2; p13)
Storing and Indexing Plan Derivations through Explanation-based Analysis of Retrieval Failures
Case-Based Planning (CBP) provides a way of scaling up domain-independent
planning to solve large problems in complex domains. It replaces the detailed
and lengthy search for a solution with the retrieval and adaptation of previous
planning experiences. In general, CBP has been demonstrated to improve
performance over generative (from-scratch) planning. However, the performance
improvements it provides are dependent on adequate judgements as to problem
similarity. In particular, although CBP may substantially reduce planning
effort overall, it is subject to a mis-retrieval problem. The success of CBP
depends on these retrieval errors being relatively rare. This paper describes
the design and implementation of a replay framework for the case-based planner
DERSNLP+EBL. DERSNLP+EBL extends current CBP methodology by incorporating
explanation-based learning techniques that allow it to explain and learn from
the retrieval failures it encounters. These techniques are used to refine
judgements about case similarity in response to feedback when a wrong decision
has been made. The same failure analysis is used in building the case library,
through the addition of repairing cases. Large problems are split and stored as
single goal subproblems. Multi-goal problems are stored only when these smaller
cases fail to be merged into a full solution. An empirical evaluation of this
approach demonstrates the advantage of learning from experienced retrieval
failure.Comment: See http://www.jair.org/ for any accompanying file
- …