332 research outputs found
A Data Collecting Strategy for Farmland WSNs using a Mobile Sink
To the characteristics of large number of sensor nodes, wide area and unbalanced energy consumption in farmland Wireless Sensor Networks, an efficient data collection strategy (GCMS) based on grid clustering and a mobile sink is proposed. Firstly, cluster is divided based on virtual grid, and the cluster head is selected by considering node position and residual energy. Then, an optimal mobile path and residence time allocation mechanism for mobile sink are proposed. Finally, GCMS is simulated and compared with LEACH and GRDG. Simulation results show that GCMS can significantly prolong the network lifetime and increase the amount of data collection, especially suitable for large-scale farmland Wireless Sensor Networks
PI3-K/Akt pathway contributes to IL-6-dependent growth of 7TD1 cells
BACKGROUND: Recently, growing evidence suggests the involvement of PI 3-K/Akt in IL-6-dependent survival and proliferative responses in several types of cells. However, whether PI 3-K/Akt plays the same role in IL-6-dependent growth of 7TD1 mouse-mouse B cell hybridoma is not known. METHODS: We investigated the activation status of Akt in 7TD1 cells induced by IL-6. With PI 3-K specific inhibitor wortmannin, we also investigated the biological roles of Akt activation in 7TD1 cells. RESULTS: IL-6 stimulated phosphorylation of Akt in a dose- and time-dependent manner in 7TD1 cells. Wortmannin significantly reduced IL-6-induced phosphorylation of Akt and IL-6-dependent growth of 7TD1 cells. Furthermore, wortmannin blocked IL-6-induced up-regulation of XIAP, but not Bcl-2 in 7TD1 cells. CONCLUSION: The data suggest that IL-6-induced PI 3-K/Akt activation is essential for the optimal growth of 7TD1 cells through up-regulation of anti-apoptosis proteins such as XIAP
The APC Algorithm of Solving Large-Scale Linear Systems: A Generalized Analysis
A new algorithm called accelerated projection-based consensus (APC) has
recently emerged as a promising approach to solve large-scale systems of linear
equations in a distributed fashion. The algorithm adopts the federated
architecture, and attracts increasing research interest; however, it's
performance analysis is still incomplete, e.g., the error performance under
noisy condition has not yet been investigated. In this paper, we focus on
providing a generalized analysis by the use of the linear system theory, such
that the error performance of the APC algorithm for solving linear systems in
presence of additive noise can be clarified. We specifically provide a
closed-form expression of the error of solution attained by the APC algorithm.
Numerical results demonstrate the error performance of the APC algorithm,
validating the presented analysis.Comment: 6 pages, 3 figure
Selective unresponsiveness to the inhibition of p38 MAPK activation by cAMP helps L929 fibroblastoma cells escape TNF-α-induced cell death
<p>Abstract</p> <p>Background</p> <p>The cyclic AMP (cAMP) signaling pathway has been reported to either promote or suppress cell death, in a cell context-dependent manner. Our previous study has shown that the induction of dynein light chain (DLC) by cAMP response element-binding protein (CREB) is required for cAMP-mediated inhibition of mitogen-activated protein kinase (MAPK) p38 activation in fibroblasts, which leads to suppression of NF-κB activity and promotion of tumor necrosis factor-α (TNF-α)-induced cell death. However, it remains unknown whether this regulation is also applicable to fibroblastoma cells.</p> <p>Methods</p> <p>Intracellular cAMP was determined in L929 fibroblastoma cells after treatment of the cells with various cAMP elevation agents. Effects of cAMP in the presence or absence of the RNA synthesis inhibitor actinomycin D or small interfering RNAs (siRNAs) against CREB on TNF-α-induced cell death in L929 cells were measured by propidium iodide (PI) staining and subsequent flow cytomety. The activation of p38 and c-Jun N-terminal protein kinase (JNK), another member of MAPK superfamily, was analyzed by immunoblotting. JNK selective inhibitor D-JNKi1 and p38 selective inhibitor SB203580 were included to examine the roles of JNK and p38 in this process. The expression of DLC or other mediators of cAMP was analyzed by immunoblotting. After ectopic expression of DLC with a transfection marker GFP, effects of cAMP on TNF-α-induced cell death in GFP+ cells were measured by PI staining and subsequent flow cytomety.</p> <p>Results</p> <p>Elevation of cAMP suppressed TNF-α-induced necrotic cell death in L929 fibroblastoma cells via CREB-mediated transcription. The pro-survival role of cAMP was associated with selective unresponsiveness of L929 cells to the inhibition of p38 activation by cAMP, even though cAMP significantly inhibited the activation of JNK under the same conditions. Further exploration revealed that the induction of DLC, the major mediator of p38 inhibition by cAMP, was impaired in L929 cells. Enforced inhibition of p38 activation by using p38 specific inhibitor or ectopic expression of DLC reversed the protection of L929 cells by cAMP from TNF-α-induced cell death.</p> <p>Conclusion</p> <p>These data suggest that the lack of a pro-apoptotic pathway in tumor cells leads to a net survival effect of cAMP.</p
AdaTT: Adaptive Task-to-Task Fusion Network for Multitask Learning in Recommendations
Multi-task learning (MTL) aims at enhancing the performance and efficiency of
machine learning models by training them on multiple tasks simultaneously.
However, MTL research faces two challenges: 1) modeling the relationships
between tasks to effectively share knowledge between them, and 2) jointly
learning task-specific and shared knowledge. In this paper, we present a novel
model Adaptive Task-to-Task Fusion Network (AdaTT) to address both challenges.
AdaTT is a deep fusion network built with task specific and optional shared
fusion units at multiple levels. By leveraging a residual mechanism and gating
mechanism for task-to-task fusion, these units adaptively learn shared
knowledge and task specific knowledge. To evaluate the performance of AdaTT, we
conduct experiments on a public benchmark and an industrial recommendation
dataset using various task groups. Results demonstrate AdaTT can significantly
outperform existing state-of-the-art baselines
Event-Triggered Relearning Modeling Method for Stochastic System with Non-Stationary Variable Operating Conditions
This study presents a novel event-triggered relearning framework for neural network modeling, designed to improve prediction precision in dynamic stochastic complex industrial systems under non-stationary and variable conditions. Firstly, a sliding window algorithm combined with entropy is applied to divide the input and output datasets across different operational conditions, establishing clear data boundaries. Following this, the prediction errors derived from the neural network under different operational states are harnessed to define a set of event-triggered relearning criteria. Once these conditions are triggered, the relevant dataset is used to recalibrate the model to the specific operational condition and predict the data under this operating condition. When the predicted data fall within the training input range of a pre-trained model, we switch to that model for immediate prediction. Compared with the conventional BP neural network model and random vector functional-link network, the proposed model can produce a better estimation accuracy and reduce computation costs. Finally, the effectiveness of our proposed method is validated through numerical simulation tests using nonlinear Hammerstein models with Gaussian noise, reflecting complex stochastic industrial processes
Marketing Budget Allocation with Offline Constrained Deep Reinforcement Learning
We study the budget allocation problem in online marketing campaigns that
utilize previously collected offline data. We first discuss the long-term
effect of optimizing marketing budget allocation decisions in the offline
setting. To overcome the challenge, we propose a novel game-theoretic offline
value-based reinforcement learning method using mixed policies. The proposed
method reduces the need to store infinitely many policies in previous methods
to only constantly many policies, which achieves nearly optimal policy
efficiency, making it practical and favorable for industrial usage. We further
show that this method is guaranteed to converge to the optimal policy, which
cannot be achieved by previous value-based reinforcement learning methods for
marketing budget allocation. Our experiments on a large-scale marketing
campaign with tens-of-millions users and more than one billion budget verify
the theoretical results and show that the proposed method outperforms various
baseline methods. The proposed method has been successfully deployed to serve
all the traffic of this marketing campaign.Comment: WSDM 23, Best Paper Candidat
Pathogenic alpha-synuclein aggregates preferentially bind to mitochondria and affect cellular respiration
Abstract
Misfolded alpha-synuclein (αSyn) is a major constituent of Lewy bodies and Lewy neurites, which are pathological hallmarks of Parkinson’s disease (PD). The contribution of αSyn to PD is well established, but the detailed mechanism remains obscure. Using a model in which αSyn aggregation in primary neurons was seeded by exogenously added, preformed αSyn amyloid fibrils (PFF), we found that a majority of pathogenic αSyn (indicated by serine 129 phosphorylated αSyn, ps-αSyn) was membrane-bound and associated with mitochondria. In contrast, only a minuscule amount of physiological αSyn was mitochondrial bound. In vitro, αSyn PFF displayed a stronger binding to purified mitochondria than did αSyn monomer, revealing a preferential mitochondria binding by aggregated αSyn. This selective mitochondrial ps-αSyn accumulation was confirmed in other neuronal and animal αSyn aggregation models that do not require exogenously added PFF and, more importantly, in postmortem brain tissues of patients suffering from PD and other neurodegenerative diseases with αSyn aggregation (α-synucleinopathies). We also showed that the mitochondrial ps-αSyn accumulation was accompanied by defects in cellular respiration in primary neurons, suggesting a link to mitochondrial dysfunction. Together, our results show that, contrary to physiological αSyn, pathogenic αSyn aggregates preferentially bind to mitochondria, indicating mitochondrial dysfunction as the common downstream mechanism for α-synucleinopathies. Our findings suggest a plausible model explaining the formation and the peculiar morphology of Lewy body and reveal that disrupting the interaction between ps-αSyn and the mitochondria is a therapeutic target for α-synucleinopathies.https://deepblue.lib.umich.edu/bitstream/2027.42/148288/1/40478_2019_Article_696.pd
Towards the Better Ranking Consistency: A Multi-task Learning Framework for Early Stage Ads Ranking
Dividing ads ranking system into retrieval, early, and final stages is a
common practice in large scale ads recommendation to balance the efficiency and
accuracy. The early stage ranking often uses efficient models to generate
candidates out of a set of retrieved ads. The candidates are then fed into a
more computationally intensive but accurate final stage ranking system to
produce the final ads recommendation. As the early and final stage ranking use
different features and model architectures because of system constraints, a
serious ranking consistency issue arises where the early stage has a low ads
recall, i.e., top ads in the final stage are ranked low in the early stage. In
order to pass better ads from the early to the final stage ranking, we propose
a multi-task learning framework for early stage ranking to capture multiple
final stage ranking components (i.e. ads clicks and ads quality events) and
their task relations. With our multi-task learning framework, we can not only
achieve serving cost saving from the model consolidation, but also improve the
ads recall and ranking consistency. In the online A/B testing, our framework
achieves significantly higher click-through rate (CTR), conversion rate (CVR),
total value and better ads-quality (e.g. reduced ads cross-out rate) in a large
scale industrial ads ranking system.Comment: Accepted by AdKDD 2
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