PB-ACR: Node Payload Balanced Ant Colony Optimal Cooperative Routing for Multi-Hop Underwater Acoustic Sensor Networks

For a given source-destination pair in multi-hop underwater acoustic sensor networks (UASNs), an optimal route is the one with the lowest energy consumptions that usually consists of the same relay nodes even under different transmission tasks. However, this will lead to the unbalanced payload of the relay nodes in the multi-hop UASNs and accelerate the loss of the working ability for the entire system. In this paper, we propose a node payload balanced ant colony optimal cooperative routing (PB-ACR) protocol for multi-hop UASNs, through combining the ant colony algorithm and cooperative transmission. The proposed PB-ACR protocol is a relay node energy consumption balanced scheme, which considers both data priority and residual energy of each relay node, aiming to reduce the occurrence of energy holes and thereby prolong the lifetime of the entire UASNs. We compare the proposed PB-ACR protocol with the existing ant colony algorithm routing (ACAR) protocol to verify its performances in multi-hop UASNs, in terms of network throughput, energy consumption, and algorithm complexity. The simulation results show that the proposed PB-ACR protocol can effectively balance the energy consumption of underwater sensor nodes and hence prolong the network lifetime

Exploiting dynamic scheduling for VM-based code obfuscation

Code virtualization built upon virtual machine (VM) technologies is emerging as a viable method for implementing code obfuscation to protect programs against unauthorized analysis. State-of-the-art VM-based protection approaches use a fixed scheduling structure where the program follows a single, static execution path for the same input. Such approaches, however, are vulnerable to certain scenarios where the attacker can reuse knowledge extracted from previously seen software to crack applications using similar protection schemes. This paper presents DSVMP, a novel VM-based code obfuscation approach for software protection. DSVMP brings together two techniques to provide stronger code protection than prior VM-based schemes. Firstly, it uses a dynamic instruction scheduler to randomly direct the program to execute different paths without violating the correctness across different runs. By randomly choosing the program execution paths, the application exposes diverse behavior, making it much more difficult for an attacker to reuse the knowledge collected from previous runs or similar applications to perform attacks. Secondly, it employs multiple VMs to further obfuscate the relationship between VM bytecode and their interpreters, making code analysis even harder. We have implemented DSVMP in a prototype system and evaluated it using a set of widely used applications. Experimental results show that DSVMP provides stronger protection with comparable runtime overhead and code size when compared to two commercial VMbased code obfuscation tools

Variety-driven rhizosphere microbiome bestows differential salt tolerance to alfalfa for coping with salinity stress

Soil salinization is a global environmental issue and a significant abiotic stress that threatens crop production. Root-associated rhizosphere microbiota play a pivotal role in enhancing plant tolerance to abiotic stresses. However, limited information is available concerning the specific variations in rhizosphere microbiota driven by different plant genotypes (varieties) in response to varying levels of salinity stress. In this study, we compared the growth performance of three alfalfa varieties with varying salt tolerance levels in soils with different degrees of salinization. High-throughput 16S rRNA and ITS sequencing were employed to analyze the rhizosphere microbial communities. Undoubtedly, the increasing salinity significantly inhibited alfalfa growth and reduced rhizosphere microbial diversity. However, intriguingly, salt-tolerant varieties exhibited relatively lower susceptibility to salinity, maintaining more stable rhizosphere bacterial community structure, whereas the reverse was observed for salt-sensitive varieties. Bacillus emerged as the dominant species in alfalfa's adaptation to salinity stress, constituting 21.20% of the shared bacterial genera among the three varieties. The higher abundance of Bacillus, Ensifer, and Pseudomonas in the rhizosphere of salt-tolerant alfalfa varieties is crucial in determining their elevated salt tolerance. As salinity levels increased, salt-sensitive varieties gradually accumulated a substantial population of pathogenic fungi, such as Fusarium and Rhizoctonia. Furthermore, rhizosphere bacteria of salt-tolerant varieties exhibited increased activity in various metabolic pathways, including biosynthesis of secondary metabolites, carbon metabolism, and biosynthesis of amino acids. It is suggested that salt-tolerant alfalfa varieties can provide more carbon sources to the rhizosphere, enriching more effective plant growth-promoting bacteria (PGPB) such as Pseudomonas to mitigate salinity stress. In conclusion, our results highlight the variety-mediated enrichment of rhizosphere microbiota in response to salinity stress, confirming that the high-abundance enrichment of specific dominant rhizosphere microbes and their vital roles play a significant role in conferring high salt adaptability to these varieties

血浆同型半胱胺酸和D-二聚体水平与急性期脑梗死各亚型的关系

Purpose-To study plasma homocysteine(Hcy)/D-dimer levels in patients with differernt subtype of acute cerebral infarction for early etiology diagnosis. Methods: The subjects were 246 acute cerebral infarction patients in the first 24 hours of stroke onset at our hospital. We divided them into large –artery atherosclerosis(LAA) group(n=66), small artery occlusion(SAO) group(n=76), cardio embolism(CE) group(n=40),stroke of other demonstrated etiology(SOE) group (n=11)and stroke of other undemonstrated etiology(SUE) group(n=51) according to the TOAST classification. Plasma homocysteine and D-diamer were determined within the first 24 hours of admission, the differences in subgroups and control group(n=121) were analyzed. Results:Plasma homocysteine levels in LAA group were signficantly higher than other groups(P<0.05), no differences in non-LAA groups(P>0.05);Plasma D-diamer levels in CE group were significant higher than other groups(P<0.05), no differences in non-CE groups(P>0.05). Conclusions: Plasma homocysteine and D-diamer level are associated with subtypes of acute cerebral infarction, and it contributed to early classification diagnosis and individual treatment of patients with acute cerebral infarction.目的：探讨血浆同型半胱胺酸和D-二聚体在急性期各亚型脑梗死之间的差异，为临床脑梗死亚型的病因学诊断提供理论依据。方法：收集我院246例24 h内发病的脑梗死患者，根据TOAST分型方法进行病因学分型：大动脉粥样硬化性脑卒中(1arge—artery atherosclerosis，LAA；n=66)、小动脉闭塞性脑卒中(small-artery occlusion ,SAO；n=76)、心源性脑栓塞(cardio embolism，CE；n=40)、其他确定原因引发的缺血性脑卒中(stroke of other demonstrated etiology，SOE；n=11)和不明原因的缺血性脑卒中(stroke of other undemonstrated etiology，SUE；n=51)。在入院24小时内测定血浆同型半胱胺酸（Hcy）和D-二聚体（DD）的含量，并与121例对照组进行比较，分析二者在不同亚型脑梗死及对照组之间的差异。结果：LAA组同型半胱氨酸水平明显高于其它4组及对照组(P<0．05) ，其他 4个亚型(SAA、CA、SOE、SUE)及对照组组间比较差异无统计学意义(P>0．05)。CE组血浆D-二聚体含量最高,显著高于其他各亚型组及对照组(P<0.05); 其他 4个亚型(SAA、CA、SOE、SUE)及对照组组间比较差异无统计学意义(P>0．05)。结论：急性期各亚型脑梗死之间血浆同型半胱胺酸和D-二聚体升高程度不同,这对于临床早期分型诊断及个体化治疗有着重要指导意义

Dirac semimetal PdTe2 temperature-dependent quasiparticle dynamics and electron-phonon coupling

Dirac semimetal PdTe2 single-crystal temperature-dependent ultrafast carrier and phonon dynamics were studied using ultrafast optical pump-probe spectroscopy. Two distinct carrier and coherent phonons relaxation processes were identified in the 5 K - 300 K range. Quantitative analysis revealed a fast relaxation process ({\tau}_f) occurring on a subpicosecond time scale which originated from electron-phonon thermalization. This was followed by a slower relaxation process ({\tau}_s) with a time scale of ~ 7-9.5 ps which originated from phonon-assisted electron-hole recombination. Two significant vibrational modes resolved at all measured temperatures and corresponded to Te atoms in-plane (E_g), and out-of-plane (A_1g), motion. As temperature increased both phonon modes softened markedly. A_1g mode frequency monotonically decreased as temperature increased. Its damping rate remained virtually unchanged. As expected, E_g decreased uniformly as temperatures rose. At temperatures above 80 K, there was insignificant change. Test results suggested that pure dephasing played an important role in the relaxation processes. PdTe2 phonon is thought responsible for its superconductive properties. Examining phonons behavior should improve the understanding of its complex superconductivity.Comment: 6 pages, 4 figure