1,162 research outputs found
The effect of baroque music on the PassPoints graphical password
Graphical passwords have been demonstrated to be the possible alternatives to traditional alphanumeric passwords. However, they still tend to follow predictable patterns that are easier to attack. The crux of the problem is users’ memory limitations. Users are the weakest link in password authentication mechanism. It shows that baroque music has positive effects on human memorizing and learning. We introduce baroque music to the PassPoints graphical password scheme and conduct a laboratory study in this paper. Results shown that there is no statistic difference between the music group and the control group without music in short-term recall experiments, both had high recall success rates. But in long-term recall, the music group performed significantly better. We also found that the music group tended to set significantly more complicated passwords, which are usually more resistant to dictionary and other guess attacks. But compared with the control group, the music group took more time to log in both in short-term and long-term tests. Besides, it appears that background music does not work in terms of hotspots
A new graphical password scheme resistant to shoulder-surfing
Shoulder-surfing is a known risk where an attacker can capture a password by direct observation or by recording
the authentication session. Due to the visual interface, this problem has become exacerbated in graphical passwords.
There have been some graphical schemes resistant or immune
to shoulder-surfing, but they have significant usability
drawbacks, usually in the time and effort to log in. In this
paper, we propose and evaluate a new shoulder-surfing
resistant scheme which has a desirable usability for PDAs. Our inspiration comes from the drawing input method in DAS and the association mnemonics in Story for sequence retrieval. The new scheme requires users to draw a curve across their password images orderly rather than click directly on them.
The drawing input trick along with the complementary
measures, such as erasing the drawing trace, displaying
degraded images, and starting and ending with randomly
designated images provide a good resistance to shoulder-surfing.
A preliminary user study showed that users were able to enter their passwords accurately and to remember them over time
The effect of baroque music on the PassPoints graphical password
Graphical passwords have been demonstrated to be the possible alternatives to traditional alphanumeric passwords. However, they still tend to follow predictable patterns that are easier to attack. The crux of the problem is users’ memory limitations. Users are the weakest link in password authentication mechanism. It shows that baroque music has positive effects on human memorizing and learning. We introduce baroque music to the PassPoints graphical password scheme and conduct a laboratory study in this paper. Results shown that there is no statistic difference between the music group and the control group without music in short-term recall experiments, both had high recall success rates. But in long-term recall, the music group performed significantly better. We also found that the music group tended to set significantly more complicated passwords, which are usually more resistant to dictionary and other guess attacks. But compared with the control group, the music group took more time to log in both in short-term and long-term tests. Besides, it appears that background music does not work in terms of hotspots
A novel pyruvate kinase and its application in lactic acid production under oxygen deprivation in Corynebacterium glutamicum
BACKGROUND: Pyruvate kinase (Pyk) catalyzes the generation of pyruvate and ATP in glycolysis and functions as a key switch in the regulation of carbon flux distribution. Both the substrates and products of Pyk are involved in the tricarboxylic acid cycle, anaplerosis and energy anabolism, which places Pyk at a primary metabolic intersection. Pyks are highly conserved in most bacteria and lower eukaryotes. Corynebacterium glutamicum is an industrial workhorse for the production of various amino acids and organic acids. Although C. glutamicum was assumed to possess only one Pyk (pyk1, NCgl2008), NCgl2809 was annotated as a pyruvate kinase with an unknown role. RESULTS: Here, we identified that NCgl2809 was a novel pyruvate kinase (pyk2) in C. glutamicum. Complementation of the WTΔpyk1Δpyk2 strain with the pyk2 gene restored its growth on d-ribose, which demonstrated that Pyk2 could substitute for Pyk1 in vivo. Pyk2 was co-dependent on Mn(2+) and K(+) and had a higher affinity for ADP than phosphoenolpyruvate (PEP). The catalytic activity of Pyk2 was allosterically regulated by fructose 1,6-bisphosphate (FBP) activation and ATP inhibition. Furthermore, pyk2 and ldhA, which encodes l-lactate dehydrogenase, were co-transcribed as a bicistronic mRNA under aerobic conditions and pyk2 deficiency had a slight effect on the intracellular activity of Pyk. However, the mRNA level of pyk2 in the wild-type strain under oxygen deprivation was 14.24-fold higher than that under aerobic conditions. Under oxygen deprivation, pyk1 or pyk2 deficiency decreased the generation of lactic acid, and the overexpression of either pyk1 or pyk2 increased the production of lactic acid as the activity of Pyk increased. Fed-batch fermentation of the pyk2-overexpressing WTΔpyk1 strain produced 60.27 ± 1.40 g/L of lactic acid, which was a 47% increase compared to the parent strain under oxygen deprivation. CONCLUSIONS: Pyk2 functioned as a pyruvate kinase and contributed to the increased level of Pyk activity under oxygen deprivation. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1186/s12896-016-0313-6) contains supplementary material, which is available to authorized users
Transgenic Eimeria magna Pérard, 1925 Displays Similar Parasitological Properties to the Wild-type Strain and Induces an Exogenous Protein-Specific Immune Response in Rabbits (Oryctolagus cuniculus L.)
Rabbit coccidiosis causes great economic losses to world rabbitries. Little work has been done considering genetic manipulation on the etiological agents, rabbit Eimeria spp. In this study, we constructed a transgenic line of Eimeria magna (EmagER) expressing enhanced yellow fluorescent protein (EYFP) and red fluorescent protein (RFP) using regulatory sequences of Eimeria tenella and Toxoplasma gondii. We observed the life cycle of EmagER and confirmed that the transgenic parasites express exogenous proteins targeted to different cellular compartments throughout the entire life cycle. EYFP was expressed mainly in the nucleus and RFP both in the nucleus and cytoplasm. Then, coccidia-free, laboratory-reared 40-day-old rabbits were primarily infected with either EmagER or wild-type strain oocysts and challenged with the wild-type strain. EmagER showed similar reproductivity and immunogenicity to the wild-type strain. Finally, we examined the foreign protein-specific immune response elicited by EmagER. Rabbits were immunized with either transgenic or wild-type oocysts. Immune response against parasite-soluble antigen, EYFP and RFP in spleen, and mesenteric lymph nodes were detected by quantitative real-time PCR. The relative expression level of IFN-γ, IL-2, and TNF-α were higher in EmagER-immunized rabbits than wild-type parasites-immunized rabbits after stimulation with EYFP and RFP. Our study confirmed that a specific immune response was induced by the exogenous protein expressed by EmagER and favored future studies on application of transgenic rabbit coccidia as recombinant vaccine vectors
Automatic Analysis of Large-scale Nanopore Data Using Hidden Markov Models
In this paper we developed a modified Hidden Markov Model (HMM) to analyze the raw nanopore experimental data. Traditionally, prior to further analysis the measured nanopore data must be pre-filtered, but the filtering usually distorts the waveform of the blockage current, especially for rapid translocations and bumping blockages. The HMM is known to be robust with respect to strong noise and thus suitable for processing the raw nanopore data, but its performance is susceptible to the setting of initial parameters. To overcome this problem, we use the Fuzzy c-Means (FCM) algorithm to initialize the HMM parameters in this work. Then we use the Viterbi training algorithm to optimize the HMM. Finally, both the simulated and experimental data analysis results are presented to show the effectiveness of the proposed method for detection of the nanopore current blockage events in analytical chemistry.publishedVersio
现代汉语总结类话语标记浅析 = Discourse Markers of Summary in Modern Chinese
总结类话语标记是人类语言共有的元话语
成分之一。现代汉语总结类话语标记包括“总
之”、“一句话”、“概括起来讲”、“总的
来看”等众多成员,根据构成成分及其结构关
系特点可以归纳为以“话/言”和“说/讲/
看”为核心成分的名词和动词两个系列。总结
类话语标记分布在前后语段之间,构建的语篇
模式为“a,X,b”,在“要点概括”的总体语
义功能之下表达概括、推论、补充、转折、让
步等多种下位语义关系。总结类话语标记的语
篇组织功能和人际互动功能是其概念表达功能
语法化的结果,在这一过程中从基本话语发展
为元话语。
A discourse marker of summary is a common meta-discourse element in human languages. Discourse markers of summary in modern Chinese contains zong zhi, yi ju hua, gai kuo qi lai jiang, zong de lai kan and others, which can be summarized as nouns and pronouns centered by hua/yan, shuo/jiang/kan in correspondence of their construction elements and features of construction relation. Discourse markers of summary distribute near the front and back syntagms, through which the discourse model is
constructed as “a, X, b”. This construction implies summary, inference, complementarity, transference, concession, and other semantic relation of subcategorization. The discourse organizing function and inter-personal interactive function of discourse markers of summary is the grammaticalization of the function of these and in this process, the discourse markers of summary develops from basic discourse to meta-discourse
Construction of Bio-Engineering Comprehensive Experimental Teaching Innovation System
Analysis of the current situation and development prospects of need of bio-engineering professionals to build the education idea of social demand-oriented, “all for students, the whole process for educating people, all-round education,” take CDIO engineering education philosophy as the guiding ideology, practice curriculum system for the carrier, developing ability as the main line, to build an “innovative educational concept - Research theory Teaching - entrepreneurial practice Teaching - specialized personnel training,” experimental zone training model, developed with the appropriate professional teaching programs, course syllabus, experiments and practical syllabus. Talents experimental area constructed has achieved good teaching results
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