216 research outputs found
Transversals in a collections of trees
Let be a fixed family of graphs on vertex set and
be a collection of elements in . We investigated the
transversal problem of finding the maximum value of when
contains no rainbow elements in . Specifically, we
determine the exact values when is a family of stars or a family
of trees of the same order with dividing . Further, all the
extremal cases for are characterized.Comment: 16pages,2figure
PREFENDER: A Prefetching Defender against Cache Side Channel Attacks as A Pretender
Cache side channel attacks are increasingly alarming in modern processors due
to the recent emergence of Spectre and Meltdown attacks. A typical attack
performs intentional cache access and manipulates cache states to leak secrets
by observing the victim's cache access patterns. Different countermeasures have
been proposed to defend against both general and transient execution based
attacks. Despite their effectiveness, they mostly trade some level of
performance for security, or have restricted security scope. In this paper, we
seek an approach to enforcing security while maintaining performance. We
leverage the insight that attackers need to access cache in order to manipulate
and observe cache state changes for information leakage. Specifically, we
propose Prefender, a secure prefetcher that learns and predicts attack-related
accesses for prefetching the cachelines to simultaneously help security and
performance. Our results show that Prefender is effective against several cache
side channel attacks while maintaining or even improving performance for SPEC
CPU 2006 and 2017 benchmarks.Comment: Submitting to a journa
Sphingosine protects aging hearts from ischemia/reperfusion injury: Superiority to sphingosine 1-phosphate and ischemic pre- and post-conditioning
Aging hearts are known to have diminished capacity to be protected against reoxygenation ischemia/reperfusion (IR) injury provided by various cardioprotective regimens. In search of a more successful regimen, we have studied the response of aged hearts to preconditioning (PC) and postconditioning (POST) elicited by sphingosine or sphingosine 1-phosphate treatment
FedBA: Non-IID Federated Learning Framework in UAV Networks
With the development and progress of science and technology, the Internet of
Things(IoT) has gradually entered people's lives, bringing great convenience to
our lives and improving people's work efficiency. Specifically, the IoT can
replace humans in jobs that they cannot perform. As a new type of IoT vehicle,
the current status and trend of research on Unmanned Aerial Vehicle(UAV) is
gratifying, and the development prospect is very promising. However, privacy
and communication are still very serious issues in drone applications. This is
because most drones still use centralized cloud-based data processing, which
may lead to leakage of data collected by drones. At the same time, the large
amount of data collected by drones may incur greater communication overhead
when transferred to the cloud. Federated learning as a means of privacy
protection can effectively solve the above two problems. However, federated
learning when applied to UAV networks also needs to consider the heterogeneity
of data, which is caused by regional differences in UAV regulation. In
response, this paper proposes a new algorithm FedBA to optimize the global
model and solves the data heterogeneity problem. In addition, we apply the
algorithm to some real datasets, and the experimental results show that the
algorithm outperforms other algorithms and improves the accuracy of the local
model for UAVs
Electric-field Control of Magnetism with Emergent Topological Hall Effect in SrRuO3 through Proton Evolution
Ionic substitution forms an essential pathway to manipulate the carrier
density and crystalline symmetry of materials via ion-lattice-electron
coupling, leading to a rich spectrum of electronic states in strongly
correlated systems. Using the ferromagnetic metal SrRuO3 as a model system, we
demonstrate an efficient and reversible control of both carrier density and
crystalline symmetry through the ionic liquid gating induced protonation. The
insertion of protons electron-dopes SrRuO3, leading to an exotic ferromagnetic
to paramagnetic phase transition along with the increase of proton
concentration. Intriguingly, we observe an emergent topological Hall effect at
the boundary of the phase transition as the consequence of the
newly-established Dzyaloshinskii-Moriya interaction owing to the breaking of
inversion symmetry in protonated SrRuO3 with the proton compositional
film-depth gradient. We envision that electric-field controlled protonation
opens a novel strategy to design material functionalities
A Sphingosine Kinase Form 2 Knockout Sensitizes Mouse Myocardium to Ischemia/Reoxygenation Injury and Diminishes Responsiveness to Ischemic Preconditioning
Sphingosine kinase (SphK) exhibits two isoforms, SphK1 and SphK2. Both forms catalyze the synthesis of sphingosine 1-phosphate (S1P), a sphingolipid involved in ischemic
preconditioning (IPC). Since the ratio of SphK1 : SphK2 changes dramatically with aging, it is important to assess the role of SphK2 in IR injury and IPC. Langendorff mouse hearts were subjected to IR (30 min
equilibration, 50 min global ischemia, and 40 min reperfusion). IPC consisted of 2 min of ischemia and 2 min of reperfusion for two cycles. At baseline, there were no differences in left ventricular developed pressure (LVDP), ± dP/dtmax, and heart rate between SphK2 null (KO)
and wild-type (WT) hearts. In KO hearts, SphK2 activity was undetectable, and SphK1 activity was unchanged compared to WT. Total SphK activity was reduced by 53%. SphK2 KO hearts subjected to IR exhibited significantly more cardiac damage (37 ± 1%
infarct size) compared with WT (28 ± 1% infarct size); postischemic recovery of LVDP
was lower in KO hearts. IPC exerted cardioprotection in WT hearts. The protective
effect of IPC against IR was diminished in KO hearts which had much higher infarction sizes (35 ± 2%) compared to the IPC/IR group in control hearts (12 ± 1%). Western analysis revealed that KO
hearts had substantial levels of phosphorylated p38 which could predispose the
heart to IR injury. Thus, deletion of the SphK2 gene sensitizes the myocardium to IR injury and
diminishes the protective effect of IPC
Crohn’s Disease Treated by Chinese Medicine
Crohn’s disease is an inflammatory bowel disease with variable clinical symptoms, it can affect the whole gastrointestinal tract from the oral cavity to the anus and lead to lower quality of life and greater social and economicloss. Traditional Chinese medicine (TCM) has a long history and is unique characteristic by the theory of overall concept and treatment based on syndrome differentiation, it should be an important part of world medicine. This chapter introduces the research advance of Crohn’s disease in TCM, including its name, location, etiology and pathogenesis, syndrome differentiation, therapeutic criteria, treatment methods and other contents. The mechanism of TCM treatment of Crohn’s disease remains to be further studied
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