Emergent User Behavior on Twitter Modelled by a Stochastic Differential Equation

Data from the social-media site, Twitter, is used to study the fluctuations in tweet rates of brand names. The tweet rates are the result of a strongly correlated user behavior, which leads to bursty collective dynamics with a characteristic 1/f noise. Here we use the aggregated "user interest" in a brand name to model collective human dynamics by a stochastic differential equation with multiplicative noise. The model is supported by a detailed analysis of the tweet rate fluctuations and it reproduces both the exact bursty dynamics found in the data and the 1/f noise.     

Visual Exploratory Search of Relationship Graphs on Smartphones

This paper presents a novel framework for Visual Exploratory Search of Relationship Graphs on Smartphones (VESRGS) that is composed of three major components: inference and representation of semantic relationship graphs on the Web via meta-search, visual exploratory search of relationship graphs through both querying and browsing strategies, and human-computer interactions via the multi-touch interface and mobile Internet on smartphones. In comparison with traditional lookup search methodologies, the proposed VESRGS system is characterized with the following perceived advantages. 1) It infers rich semantic relationships between the querying keywords and other related concepts from large-scale meta-search results from Google, Yahoo! and Bing search engines, and represents semantic relationships via graphs; 2) the exploratory search approach empowers users to naturally and effectively explore, adventure and discover knowledge in a rich information world of interlinked relationship graphs in a personalized fashion; 3) it effectively takes the advantages of smartphones’ user-friendly interfaces and ubiquitous Internet connection and portability. Our extensive experimental results have demonstrated that the VESRGS framework can significantly improve the users’ capability of seeking the most relevant relationship information to their own specific needs. We envision that the VESRGS framework can be a starting point for future exploration of novel, effective search strategies in the mobile Internet era.     

All-Orientation Search and All-Placement Search in Comparative Molecular Field Analysis

Three sets of molecules have been used to study the conventional CoMFA procedure. For all the three test sets, the resulting q² values were observed to vary simply because of the change in the orientation or placement of the aligned molecules. The reason is believed to root in the imperfect sampling of the molecular field. We have introduced two new strategies, all-orientation search (AOS) and all-placement search (APS), to optimize the sampling process. By rotating and translating the molecular aggregate within the grid systematically, all the possible samplings of the molecular field are tested and subsequently the one with the highest q² value can be picked out. We have also demonstrated that the combined application of AOS/APS with GOLPE procedure can yield results better than the ones by using them respectively.Electronic Supplementary Material available.     

Life Satisfaction and the Pursuit of Happiness on Twitter

Life satisfaction refers to a somewhat stable cognitive assessment of one’s own life. Life satisfaction is an important component of subjective well being, the scientific term for happiness. The other component is affect: the balance between the presence of positive and negative emotions in daily life. While affect has been studied using social media datasets (particularly from Twitter), life satisfaction has received little to no attention. Here, we examine trends in posts about life satisfaction from a two-year sample of Twitter data. We apply a surveillance methodology to extract expressions of both satisfaction and dissatisfaction with life. A noteworthy result is that consistent with their definitions trends in life satisfaction posts are immune to external events (political, seasonal etc.) unlike affect trends reported by previous researchers. Comparing users we find differences between satisfied and dissatisfied users in several linguistic, psychosocial and other features. For example the latter post more tweets expressing anger, anxiety, depression, sadness and on death. We also study users who change their status over time from satisfied with life to dissatisfied or vice versa. Noteworthy is that the psychosocial tweet features of users who change from satisfied to dissatisfied are quite different from those who stay satisfied over time. Overall, the observations we make are consistent with intuition and consistent with observations in the social science research. This research contributes to the study of the subjective well being of individuals through social media.     

幼犬个性特征的探索性因素分析

在文献分析、开放式问卷调查和专家访谈的基础上编制幼犬(Canis lupus familiaris)个性量表,对德国牧羊犬、拉布拉多犬和英国史宾格犬3个品种的60日龄幼犬进行标准化行为测验,运用探索性因素分析得出,幼犬存在游戏性、社会性和好奇/无畏3个个性特质.分析品种间个性特征差异时发现,拉布拉多犬游戏性特质显著高于德国牧羊犬和史宾格犬(P＜0.01),德国牧羊犬社会性特质显著高于拉布拉多犬和史宾格犬(P＜0.01),拉布拉多犬好奇/无畏特质显著高于德国牧羊犬和史宾格犬(P＜0.01).结果表明,编制的幼犬个性量表具有较高的信度和效度,可用于描述和比较幼犬个体差异.不同品种幼犬个性特征存在差异.     

高中生物探究式实验教学设计研究及案例分析

“探究式学习”促使学生的学习方式和教师的教学方式发生深刻的变革.阐述了探究式学习、实验操作技能和探究式实验教学模式这三个概念的内涵.同时,对高中生物一个重要的验证性实验“叶绿体中色素的提取和分离”进行了改进,实施了探究式实验教学设计并进行了教学实践以及分析,旨在探讨如何培养学生的实验操作技能.由此可得出结论:开展探究式实验教学,既能通过规范的实验操作,培养学生的实验操作技能,又能培养学生的综合探究能力并树立实事求是的科学态度;利用随堂式的实验教学评价,能很好发挥探究式学习的成效.     

热分析方法及裂解气相色谱在树木分类上的试探性研究

热分析是在程序控制温度下自动连续跟踪物质的物理性质与温度关系的一类技术。尤其是差热分析和热重法与其他手段联合,可用于化合物稳定性、分解机理和相转变等方面的研究。由于种子是一个复杂化合物的有机体,我们期望发现各不同种子化合物之间在成份上和组成方式上的共性和差异性,从热化学的角度对木本植物进行热化学分类。我们选用针叶类两个科(松科、杉木科)的种子进行了DTA、TG、550℃裂解气相色谱分析;300℃逸出成份分析,发现松科种子DTA图上在240±5℃有一个共同的吸热峰,而杉木则出现在320±5 ℃。TG曲线同科的不同种之间非常相似,逸出成份分析和裂解气相色谱分析同科的不同种之间也具共同特征,且又显示出一定的差异性。这种分类方法是可靠的,且可为树木(或植物)分类学提供更有价值的信息。     

马铃薯AGPase活力反馈调控光合速率定量分析

为了揭示ADP-葡萄糖焦磷酸化酶(AGPase)改变对叶片光合作用的反馈调控,以改变AGPase活力的马铃薯转化株系为材料,测定了其AGPase活力(AA)、块茎淀粉积累量(SC)、叶片光合速率(PR)、叶绿素(CC)和蔗糖含量(SUC)等;测定结果分析显示,各株系的AGPase活力(AA)、块茎淀粉积累量(SC)和叶片光合速率(PR)间存在显著差异,且均显著高于对照;株系间AGPase活力、块茎淀粉含量和叶片光合速率呈显著正相关性;每单位AGPase活力上升可贡献贮藏器官淀粉积累增加2.5%,且是影响叶片光合速率的重要因素;结果表明,AGPase不仅是下游淀粉积累的限速酶,而且可向上游反馈调控光合速率。     

Virtual World Currency Value Fluctuation Prediction System Based on User Sentiment Analysis

In this paper, we present a method for predicting the value of virtual currencies used in virtual gaming environments that support multiple users, such as massively multiplayer online role-playing games (MMORPGs). Predicting virtual currency values in a virtual gaming environment has rarely been explored; it is difficult to apply real-world methods for predicting fluctuating currency values or shares to the virtual gaming world on account of differences in domains between the two worlds. To address this issue, we herein predict virtual currency value fluctuations by collecting user opinion data from a virtual community and analyzing user sentiments or emotions from the opinion data. The proposed method is straightforward and applicable to predicting virtual currencies as well as to gaming environments, including MMORPGs. We test the proposed method using large-scale MMORPGs and demonstrate that virtual currencies can be effectively and efficiently predicted with it.     

National and Local Influenza Surveillance through Twitter: An Analysis of the 2012-2013 Influenza Epidemic

Social media have been proposed as a data source for influenza surveillance because they have the potential to offer real-time access to millions of short, geographically localized messages containing information regarding personal well-being. However, accuracy of social media surveillance systems declines with media attention because media attention increases “chatter” – messages that are about influenza but that do not pertain to an actual infection – masking signs of true influenza prevalence. This paper summarizes our recently developed influenza infection detection algorithm that automatically distinguishes relevant tweets from other chatter, and we describe our current influenza surveillance system which was actively deployed during the full 2012-2013 influenza season. Our objective was to analyze the performance of this system during the most recent 2012–2013 influenza season and to analyze the performance at multiple levels of geographic granularity, unlike past studies that focused on national or regional surveillance. Our system’s influenza prevalence estimates were strongly correlated with surveillance data from the Centers for Disease Control and Prevention for the United States (r = 0.93, p < 0.001) as well as surveillance data from the Department of Health and Mental Hygiene of New York City (r = 0.88, p < 0.001). Our system detected the weekly change in direction (increasing or decreasing) of influenza prevalence with 85% accuracy, a nearly twofold increase over a simpler model, demonstrating the utility of explicitly distinguishing infection tweets from other chatter.     

Search and Analysis of Identical Reverse Octapeptides in Unrelated Proteins

For the past few decades, intensive studies have been carried out in an attempt to understand how the amino acid sequences of proteins encode their three dimensional structures to perform their specific functions. In order to understand the sequence-structure relationship of proteins, several sub-sequence search studies in non-redundant sequence-structure databases have been undertaken which have given some fruitful clues. In our earlier work, we analyzed a set of 3124 non-redundant protein sequences from the Protein Data Bank (PDB) and retrieved 30 identical octapeptides having different secondary structures. These octapeptides were characterized by using different computational procedures. This prompted us to explore the presence of octapeptides with reverse sequences and to analyze whether these octapeptides would adopt similar structures as that of their parent octapeptides. Our identical reverse octapeptide search resulted in the finding of eight octapeptide pairs (octapeptide and reverse octapeptide) with similar secondary structure and 23 octapeptide pairs with different secondary structures. In the present work, the geometrical and biophysical characteristics of identical reverse octapeptides were explored and compared with unrelated octapeptide pairs by using various computational tools. We thus conclude that proteins containing identical reverse octapeptides are not very abundant and residues in the octapeptide pairs do not contribute to the stability of the protein. Furthermore, compared to unrelated octapeptides, identical reverse octapeptides do not show certain biophysical and geometrical properties.     

医院社会满意度测评体系探讨与实践研究(英文)

目的:探讨医院社会满意度测评体系,进行社会满意度调查,为医院提升社会满意度提出建议。方法:采用医院探索的社会满意度测评体系,进行医院社会满意度调查。结果:医院社会满意度测评体系包括定量测评和定性测评。调查结果显示门诊患者中对办卡、挂号、缴费服务的满意度(3.95)、住院患者住院费用知晓度(3.87)、患者医疗费用(4.27)的满意度较低。定性评价满意度较低的主要有医患沟通和医生服务态度。结论:医院社会满意度测评体系能够比较系统地反映医院存在的问题。医院的总体社会满意度处在较高的水平,但针对医患沟通、基本服务态度等问题需要引起医院管理者的重视。     

Search for bioorganic compounds and organisms on Mars

A prototype of new instrument is under construction as a part of Russian Mars program to search for bioorganic compounds and microorganisms which might be frozen in rock under the places where the traces of water were found or near the poles of Mars. The proposed instrument consists of a quadrupole mass spectrometer (QMS) to detect chemical compounds and a fluorescent microscope system (FMS) to detect organisms and bioorganic compounds in bulk.     

An 'Importance' Map of Signs and Symptoms to Classify Diabetic Polyneuropathy: An Exploratory Data Analysis

Aims/Hypothesis

Early diagnosis of diabetic polyneuropathy (DPN) is critical for a good prognosis. We aimed to identify different groups of patients, based on the various common clinical signs and symptoms of DPN, that represent a progressive worsening of the disease before the onset of plantar ulceration or amputation. We also sought to identify the most important DPN-related variables that can discriminate between groups, thus representing the most informative variables for early detection.

Methods

In 193 diabetic patients, we assessed 16 DPN-related signs, symptoms, and foot characteristics, based on the literature and the International Consensus on the Diabetic Foot. We used multiple correspondence analysis and the Kohonen algorithm to group the variables into micro and macro-classes and to identify clusters of patients that represent different DPN conditions.

Results

Four distinct groups were observed. One group showed no indication of DPN. The remaining groups were characterized by a progressive loss of the vibration perception, without a worsening of symptoms or tactile perception. The 2 intermediate groups presented different aspects of DPN: one showed mostly DPN symptoms and the other showed the incipient vibration impairment, callus and crack formation, and foot arch alteration. The fourth group showed more severe foot and DPN conditions, including ulceration and amputation, absence of vibration and tactile perception (irrespective of how many compromised foot areas), and worse foot deformities and callus and crack formation.

Conclusion

Vibration perception was more informative than tactile sensitivity in discriminating early DPN onset because its impairment was evident in more groups. Symptoms and callus and cracks did not discriminate the severity status and should be interpreted in association with other clinical variables. Reconsideration of the current screening techniques is needed to clinically determine the early onset of neuropathy using tactile perception.     

Feedback on Trait or Action Impacts on Caudate and Paracingulum Activity

There is a general conception that positive associations to one’s trait, e.g. ‘I’m clever’, are beneficial for cognitive performance. Scientific evidence shows that this is a simplification. In this functional magnetic resonance imaging (fMRI) study we used written trial-based trait feedback ‘you are clever’, or task feedback ‘your choice was correct’, on each correct response of a rule-switching task, to investigate how the character of positive self-associations influences performance outcome. Twenty participants took part in this crossover design study. We found that trait feedback was less beneficial for motivation and performance improvement, and resulting in enhanced neural activation on more difficult bivalent rule trials. This indicates that the task was treated as more complex in this condition. For example, ‘you are clever’ feedback led to enhanced activation in anterior caudate nucleus, an area known to process uncertainty. We further observed that activation in anterior paracingulate cortex was sensitive to whether self-reflection was imposed by external feedback or generated from internal processes, where the latter activation correlated positively with performance when following after task feedback. Our results illustrate how feedback can evoke self-reflections that either help or hinder motivation and performance, most likely by impacting on processes of uncertainty. The results support social psychological models stipulating that trait focus take resources away from task focus.     

植被变化对气候的反馈机制及调节效应

植被通过光合作用固定大气中的CO₂来减缓温室效应,同时植被也通过改变地表能量收支影响温室效应。在过去的气候-植被研究中,大多关注气候变化对植被的影响,而植被对气候反馈的研究相对较少。植被通过调节地表能量收支、水通量等重要地气过程影响局地、区域乃至全球气候,在气候变化中的作用十分重要。因此,需要厘清植被对气候的反馈效应机制及其结果,并识别其地域差异。从生物地球物理和生物地球化学过程两方面分析植被与气候之间的作用机制,对全球及关键区域内植被变化对局地、区域乃至全球的气候反馈效应进行了系统总结：（1）生物地球物理反馈的区域特征明显,生物地球化学反馈则表现在全球尺度上,二者相互作用但难以统一;（2）植被破坏带来的气候影响在气温效应方面与生态系统的类型及地理分布相关：热带森林破坏带来增温效应,北方森林破坏带来降温效应,温带森林破坏则会通过增加森林反照率抵消丢失的固碳降温效应,气温效应表现不明显;（3）当前研究对关键过程机制考虑不够完善,不同研究方法的结果差异较大,且缺乏高质量观测数据的验证;同时考虑生物地球物理和生物地球化学的净气候反馈研究尚无法支撑植树造林对气候变化单一减缓作用的常规理解。本文可为科学评估植树造林对气候变化作用的方向与强度提供理论依据。