一种可证明安全的消息认证码

消息认证码是保证消息完整性的重要工具,它广泛应用于各种安全系统中.随着可证明安全理论的逐渐成熟,具备可证明安全的消息认证码无疑成为人们的首选.本文基于XOR MAC和PMAC的构造方法,使用分组密码构造了一种确定性、可并行的消息认证码-DXOR MAC(Deterministic XOR MAC).在底层分组密码是伪随机置换的假设下,本文使用Game-Playing技术量化了攻击者成功伪造的概率,从而证明了其安全性.

XOR-MAC消息认证码的安全性新证明

消息认证码(Message Authentication Codes,MACs)是保证消息完整性的重要工具.Bellare等人提出了称为XOR-MAC的消息认证码,界定了攻击者成功伪造的概率,从而证明了其安全性,但是他们给出的证明方法较为复杂.本文使用Game-Playing技术采用新的安全性定义证明了XOR-MAC的安全性,证明方法简单明了;在底层所使用的分组密码是伪随机置换的假设下,量化了该消息认证码与随机函数之间区分的概率.

Hydration of drug-DNA complexes: Greater water uptake for adriamycin compared to daunomycin

Water is an integral part of DNA, and the conserved water molecules at the binding sites can modulate drug binding to DNA or protein. We report here that anthracycline antitumor antibiotics, adriamycin (AM) and daunomycin (DM), binding to DNA is accompanied by different hydration changes, with AM binding resulting in the uptake of about twice as many water molecules as DM. These results indicate that water is playing an important role in drug binding to DNA.

A toll receptor from Chinese shrimp Fenneropenaeus chinensis is responsive to Vibrio anguillarum infection

Toll-like receptors (TLRs) are an evolutionarily ancient family of pattern recognition receptors (PRRs), playing a crucial role in innate immune responses. Here we present a Toll homolog from Chinese shrimp Fenneropenaeus chinensis, designated FcToll. The full-length cDNA of FcToll is 4115 bp including a poly A-tail of 16 bp, encoding a putative protein of 931 amino acids. The predicted protein consists of an extracellular domain with a potential signal peptide, 16 leucine-rich repeats (LRR), two LRR-C-terminal (LRR-CT) motifs, and two LRR-N-terminal (LRR-NT) motifs, followed by a transmembrane segment of 23 amino acids, and a cytoplasmic Toll/Interteukin-IR (TIR) domain of 139 residues. Genomic structure of FcToll gene contains five exons and four introns. Phylogenetic analysis revealed that it belongs to insect-type invertebrate Toll family. Transcripts of FcToll gene were constitutively expressed in various tissues, with predominant level in lymphoid organ. Real-time PCR assays demonstrated that expression patterns of FcToll were distinctly modulated after bacterial or viral stimulation, with significant enhancement after 5 h post-Vibrio anguillorum challenge but markedly reduced levels immediately after white spot syndrome virus (WSSV) exposure. These results suggest that FcToll might be involved in innate host defense, especially against the pathogen V. anguillarum. (c) 2008 Elsevier Ltd. All rights reserved.

A broad deglacial delta C-13 minimum event in planktonic foraminiferal records in the Okinawa Trough

The equatorial Pacific upwelling zone has been suspected of playing an important role in the global atmospheric CO2 changes associated with glacial-interglacial cycles. In order to assess the influencing scope of the surface water deglacial delta(13)C minimum in the tropical low-latitude Pacific, the core DGKS9603, collected from the middle Okinawa Trough, was examined for 4513 C records of planktonic foraminifera N. dutertrei and G. ruber. The planktonic foraminiferal delta(13)C records show a clear decreasing event from 20 to 6 cal. kaBP., which is characterized by long duration of about 14 ka and amplitude shift of 0.4 x 10(-3). Its minimum value occurred at 15.7 cal kaBP. The event shows fairly synchrony with the surface water deglacial delta(13)C minimum identified in the tropical Pacific and its marginal seas. Because there is no evidence in planktonic foraminiferal fauna and 45180 records for upwelling and river runoff enhancement, the broad deglacial delta(13)C minimum event in planktonic foraminiferal records revealed in core DGKS9603 might have been the direct influencing result of the deglacial surface water of the tropical Pacific. The identification for the event in the Okinawa Trough provides new evidence that the water evolution in the tropical low-latitude Pacific plays a key role in large regional, even global carbon cycle.

Dynamics of intraseasonal sea level and thermocline variability in the equatorial Atlantic during 2002-03

Satellite and in situ observations in the equatorial Atlantic Ocean during 2002-03 show dominant spectral peaks at 40-60 days and secondary peaks at 10-40 days in sea level and thermocline within the intraseasonal period band (10-80 days). A detailed investigation of the dynamics of the intraseasonal variations is carried out using an ocean general circulation model, namely, the Hybrid Coordinate Ocean Model (HYCOM). Two parallel experiments are performed in the tropical Atlantic Ocean basin for the period 2000-03: one is forced by daily scatterometer winds from the Quick Scatterometer (QuikSCAT) satellite together with other forcing fields, and the other is forced by the low-passed 80-day version of the above fields. To help in understanding the role played by the wind-driven equatorial waves, a linear continuously stratified ocean model is also used. Within 3 degrees S-3 degrees N of the equatorial region, the strong 40-60-day sea surface height anomaly (SSHA) and thermocline variability result mainly from the first and second baroclinic modes equatorial Kelvin waves that are forced by intraseasonal zonal winds, with the second baroclinic mode playing a more important role. Sharp 40-50-day peaks of zonal and meridional winds appear in both the QuikSCAT and Pilot Research Moored Array in the Tropical Atlantic (PIRATA) data for the period 2002-03, and they are especially strong in 2002. Zonal wind anomaly in the central-western equatorial basin for the period 2000-06 is significantly correlated with SSHA across the equatorial basin, with simultaneous/ lag correlation ranging from-0.62 to 0.74 above 95% significance. Away from the equator (3 degrees-5 degrees N), however, sea level and thermocline variations in the 40-60-day band are caused largely by tropical instability waves (TIWs). On 10-40-day time scales and west of 10 degrees W, the spectral power of sea level and thermocline appears to be dominated by TIWs within 5 degrees S-5 degrees N of the equatorial region. The wind-driven circulation, however, also provides a significant contribution. Interestingly, east of 10 W, SSHA and thermocline variations at 10 40- day periods result almost entirely from wind-driven equatorial waves. During the boreal spring of 2002 when TIWs are weak, Kelvin waves dominate the SSHA across the equatorial basin (2 degrees S-2 degrees N). The observed quasi-biweekly Yanai waves are excited mainly by the quasi-biweekly meridional winds, and they contribute significantly to the SSHA and thermocline variations in 1 degrees-5 degrees N and 1 degrees-5 degrees S regions.

pCO(2) and carbon fluxes across sea-air interface in the Changjiang Estuary and Hangzhou Bay

Partial pressure of CO2 (pCO(2)) was investigated in the Changjiang (Yangtze River) Estuary, Hangzhou Bay and their adjacent areas during a cruise in August 2004, China. The data show that pCO(2) in surface waters of the studied area was higher than that in the atmosphere with only exception of a patch east of Zhoushan Archipelago. The pCO(2) varied from 168 to 2 264 mu atm, which fell in the low range compared with those of other estuaries in the world. The calculated sea-air CO2 fluxes decreased offshore and varied from -10.0 to 88.1 mmol m(-2) d(-1) in average of 24.4 +/- 16.5 mmol m(-2) d(-1). Although the area studied was estimated only 2 x 10(4) km(2), it emitted (5.9 +/- 4.0) x 10(3) tons of carbon to the atmosphere every day. The estuaries and their plumes must be further studied for better understanding the role of coastal seas playing in the global oceanic carbon cycle.

一个简单的机器人视觉引导装配实验系统

本文对视觉控制下的一个简单实验室装配系统作了介绍,讨论了系统组成、机器人控制、二维图象特征的提取、对物体自动识别、定位定向、系统标定、实现垒积木装配工作.本实验系统用的是我所研制的国内第一台示教再现机器人.

人工源频率域大地电磁法正反演研究

The CSAMT method is playing an important role in the exploration of geothermal and the pre-exploration in tunnel construction project recently. In order to instruct the interpretation technique for the field data, the forward method from ID to 3D and inversion method in ID and 2D are developed in this paper for the artificial source magnetotelluric in frequency domain. In general, the artificial source data are inverted only after the near field is corrected on the basis of the assumption of half-homogeneous space; however, this method is not suitable for the complex structure because the assumption is not valid any more. Recently the new idea about inversion scheme without near field correction is published in order to avoid the near field correction error. We try to discuss different inversion scheme in ID and 2D using the data without near field correction.The numerical integration method is used to do the forward modeling in ID CSAMT method o The infinite line source is used in the 2D finite-element forward modeling, where the near-field effect is occurred as in the CSAMT method because of using artificial source. The pseudo-delta function is used to modeling the source distribution, which reduces the singularity when solving the finite-element equations. The effect on the exploration area is discussed when anomalous body exists under the source or between the source and exploration area; A series of digital test show the 2D finite element method are correct, the results of modeling has important significant for CSAMT data interpretation. For 3D finite-element forward modeling, the finite-element equation is derived by Galerkin method and the divergence condition is add forcedly to the forward equation, the forward modeling result of the half homogeneous space model is correct.The new inversion idea without near field correction is followed to develop new inversion methods in ID and 2D in the paper. All of the inversion schemes use the data without near field correction, which avoid introducing errors caused by near field correction. The modified grid parameter method and the layer-by-layer inversion method are joined in the ID inversion scheme. The RRI method with artificial source are developed and finite-element inversion method are used in 2D inversion scheme. The inversion results using digital data and the field data are accordant to the model and the known geology data separately, which means the inversion without near field correction is accessible. The feasibility to invert the data only in exploration area is discussed when the anomalous body exists between the source and the exploration area.

风险偏好为什么是不稳定的？——后悔调节风险偏好的理论探索

Emotion is one of the most popular spots in recent decision making research, while regret is always being considered as the most relevant emotion with decision making. Current article firstly reviewed the literature of regret theory to date to profile the relation between regret and decision making under uncertainty through three mainlines: experienced regret, anticipated regret and regret orientation, respectively. And then, based on the theory of regret regulation raised by Zeelenberg recently, we came up with a theory of risk preference regulated by regret. Then three studies were conducted under the current framework, by using experiment, survey, and quasi experiment design. The major findings were below: In study 1, when playing ultimatum game, risk preference in decision making can be determined by experienced regret and anticipated regret of risk aversion, which made individual risk taking; In study 2, survey showed that risk orientation was negatively related with risk taking (health/safety, recreational and social); In study 3, when asked the Asian Disease Problem, risk preference can be determined by the coherence of the risk preference between the past decision and the current alternative. Individuals much more like alternative with the same risk preference of the past decision. A two way interaction was found, regret orientation, as a personality, was found as a moderator. Individuals with high regret orientation were more sensitive to the coherence of the risk preference than those with low regret orientation. Three studies provide fruitful evidences for the theory of risk preference regulated by regret in different prospective, show us the function of regret in decision making.

中国版一般能力倾向测验的信度和效度的初步检验

General aptitude tests have been playing an important role in vocational guidance and preliminary personnel selection. The present research aimed at the estimation of the reliability and validity of the preliminarily constructed Chinese version of the General Aptitude Test Battery (GATB). A Chinese version of GATB was developed on the basis of the Japanese version of GATB at first. It was then administered to a sample of nearly 500 secondary school students in Beijing City. And its reliability and validity were studied through a series of univariate and multivariate statistical techniques. The results showed that the reliability of the test battery and the criteria-related validities of some subtests were acceptable. Concerning construct validity, three or four common factors were identified by exploratory factor analysis, and a simpler reasonable four-factor-solution was approached by confirmatory factor analysis; desirable group differences were also discovered by analyses of variance and multivariate analysis of variance. Generally, it has been demonstrated that the reliability and validity of the Chinese version of GATB constructed in the present research are satisfactory.

Rapid identification of pathogenic bacteria by capillary electrophoretic analysis of rRNA genes

Molecular diagnosis is playing an increasingly important role in the rapid detection and identification of pathogenic organisms in clinical samples. The genetic variation of ribosomal genes in bacteria offers an alternative to culturing for the detection and identification of these organisms. Here 16S rRNA and 16S-23S rRNA spacer region genes were chosen as the amplified targets for single-strand conformation polymorphism (SSCP) and restriction fragment length polymorphism (RFLP) capillary electrophoresis analysis and bacterial identification. The multiple fluorescence based SSCP method for the 16S rRNA gene and the RFLP method for the 16S-23S rRNA spacer region gene were developed and applied to the identification of pathogenic bacteria in clinical samples, in which home-made short-chained linear polyacrylamide (LPA) was used as a sieving matrix; a higher sieving capability and shorter analysis time were achieved than with a commercial sieving matrix because of the simplified template preparation procedure. A set of 270 pathogenic bacteria representing 34 species in 14 genera were analyzed, and a total of 34 unique SSCP patterns representing 34 different pathogenic bacterial species were determined. Based on the use of machine code to represent peak patterns developed in this paper, the identification of bacterial species becomes much easier.

Early determinants of overweight and obesity at 5 years old in preschoolers from inner of Minas Gerais, Brazil

Introduction: Brazil is experiencing a nutritional transition characterized by a reduction in the prevalence of nutritional deficits and an increase in overweight and obesity, not only in adults but also in children and adolescents.Objectives: This study was designed to evaluate the factors associated with overweight and obesity in Brazilian 5-year-old preschoolers.Methods: A cross-sectional study of a cohort of 232 preschoolers born in Diamantina/Minas Gerais, Brazil, was undertaken. the data, including socioeconomic status, anthropometry, diet, previous history of the preschoolers and family history, were collected between July of 2009 and July of 2010. To identify the factors associated with overweight and obesity, a logistic regression and a hierarchical model were undertaken.Results: Overweight and obesity occurred in 17.2% of the preschoolers. After adjusting for mother's obesity, per capita income, protective food intake, weight gain at age 0-4 months and time spent playing, the factors associated with overweight and obesity that reached statistical significance were mother's obesity [OR = 3.12 (95% CI 1.41-6.91), P = 0.01], weight gain of more than 0.85 kg/month in the first four months of life [OR = 2.16 (95% CI 1.01-4.64), P = 0.041 and lower per capita income [OR = 0.32 (95 %CI 0.13-0.79), P = 0.01].Conclusion: the results show that more weight gain during the first four months of life and being born of mothers with obesity increased the odds of overweight/obesity in the preschoolers, while lower per capita income was a protective factor.

Agency and animation: the performance of interactive game characters

As an animator and practice-based researcher with a background in games development, I am interested in technological change in the video game medium, with a focus on the tools and technologies that drive game character animation and interactive story. In particular, I am concerned with the issue of ‘user agency’, or the ability of the end user to affect story development—a key quality of the gaming experience and essential to the aesthetics of gaming, which is defined in large measure by its interactive elements. In this paper I consider the unique qualities of the video game1 as an artistic medium and the impact that these qualities have on the production of animated virtual character performances. I discuss the somewhat oppositional nature of animated character performances found in games from recent years, which range from inactive to active—in other words, low to high agency. Where procedural techniques (based on coded rules of movement) are used to model dynamic character performances, the user has the ability to interactively affect characters in real-time within the larger sphere of the game. This game play creates a high degree of user agency. However, it lacks the aesthetic nuances of the more crafted sections of games: the short cut-scenes, or narrative interludes where entire acted performances are mapped onto game characters (often via performance capture)2 and constructed into relatively cinematic representations. While visually spectacular, cut-scenes involve minimal interactivity, so user agency is low. Contemporary games typically float between these two distinct methods of animation, from a focus on user agency and dynamically responsive animation to a focus on animated character performance in sections where the user is a passive participant. We tend to think of the majority of action in games as taking place via playable figures: an avatar or central character that represents a player. However, there is another realm of characters that also partake in actions ranging from significant to incidental: non-playable characters, or NPCs, which populate action sequences where game play takes place as well as cut scenes that unfold without much or any interaction on the part of the player. NPCs are the equivalent to supporting roles, bit characters, or extras in the world of cinema. Minor NPCs may simply be background characters or enemies to defeat, but many NPCs are crucial to the overall game story. It is my argument that, thus far, no game has successfully utilized the full potential of these characters to contribute toward development of interactive, high performance action. In particular, a type of NPC that I have identified as ‘pivotal’3—those constituting the supporting cast of a video game—are essential to the telling of a game story, particularly in genres that focus on story and characters: adventure games, action games, and role-playing games. A game story can be defined as the entirety of the narrative, told through non-interactive cut-scenes as well a interactive sections of play, and development of more complex stories in games clearly impacts the animation of NPCs. I argue that NPCs in games must be capable of acting with emotion throughout a game—in the cutscenes, which are tightly controlled, but also in sections of game play, where player agency can potentially alter the story in real-time. When the animated performance of NPCs and user agency are not continuous throughout the game, the implication is that game stories may be primarily told through short movies within games, making it more difficult to define video games animation as a distinct artistic medium.