Temporal evolution of tagging subnetwork features and motif under different activity levels – take the Q&A community Zhihu as an example

Purpose This paper aims to study the characteristics and evolution rules of tagging knowledge network for users with different activity levels in question-and-answer (Q&A) community represented by Zhihu. Design/methodology/approach A random sample of issue tag data generated by topics in the Zhihu network environment is selected. By defining user quality and selecting the top 20% and bottom 20% of users to focus on, i.e. top users and bot users, the authors apply time slicing for both types of data to construct label knowledge networks, use Q-Q diagrams and ARIMA models to analyze network indicators and introduce the theory and methods of network motif. Findings This study shows that when the power index of degree distribution is less than or equal to 3.1, the ARIMA model with rank index of label network has a higher fitting degree. With the development of the community, the correlation between tags in the tagging knowledge network is very weak. Research limitations/implications It is not comprehensive and sufficient to classify users only according to their activity levels. And traditional statistical analysis is not applicable to large data sets. In the follow-up work, the authors will further explore the characteristics of the network at a larger scale and longer timescale and consider adding more node features, including some edge features. Then, users are statistically classified according to the attributes of nodes and edges to construct complex networks, and algorithms such as machine learning and deep learning are used to calculate large-scale data sets to deeply study the evolution of knowledge networks. Practical implications This paper uses the real data of the Zhihu community to divide users according to user activity and combines the theoretical methods of statistical testing, time series and network motifs to carry out the time series evolution of the knowledge network of the Q&A community. And these research methods provide other network problems with some new ideas. Research has found that user activity has a certain impact on the evolution of the tagging network. The tagging network followed by users with high activity level tends to be stable, and the tagging network followed by users with low activity level gradually fluctuates. Social implications Research has found that user activity has a certain impact on the evolution of the tagging network. The tagging network followed by users with high activity level tends to be stable, and the tagging network followed by users with low activity level gradually fluctuates. For the community, understanding the formation mechanism of its network structure and key nodes in the network is conducive to improving the knowledge system of the content, finding user behavior preferences and improving user experience. Future research work will focus on identifying outbreak points from a large number of topics, predicting topical trends and conducting timely public opinion guidance and control. Originality/value In terms of data selection, the user quality is defined; the Zhihu tags are divided into two categories for time slicing; and network indicators and network motifs are compared and analyzed. In addition, statistical tests, time series analysis and network modality theory are used to analyze the tags.

Risk Factors for Contra-Lateral Secondary Anterior Cruciate Ligament Injury: A Systematic Review with Meta-Analysis

Background The risk of sustaining a contra-lateral anterior cruciate ligament (C-ACL) injury after primary unilateral ACL injury is high. C-ACL injury often contributes to a further decline in function and quality of life, including failure to return to sport. There is, however, very limited knowledge about which risk factors that contribute to C-ACL injury. Objective To systematically review instrinsic risk factors for sustaining a C-ACL injury. Methods A systematic review with meta-analysis was performed according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. Four databases (MEDLINE, CINAHL, EMBASE, Sport Discus) were searched from inception to January 2020. Inclusion criteria were prospective or retrospective studies investigating any intrinsic risk factor for future C-ACL injury. Meta-analysis was performed and expressed as odds ratios (OR) if two or more articles assessed the same risk factor. Results 44 moderate-to-high quality studies were eventually included in this review, whereof 35 studies were eligible for meta-analysis, including up to 59 000 individuals. We identified seven factors independently increasing the odds of sustaining a C-ACL injury (in order of highest to lowest OR): (1) returning to a high activity level (OR 3.26, 95% CI 2.10–5.06); (2) Body Mass Index < 25 (OR 2.73, 95% CI 1.73–4.36); (3) age ≤ 18 years (OR 2.42, 95% CI 1.51–3.88); (4) family history of ACL injury (OR 2.07, 95% CI 1.54–2.80); (5) primary ACL reconstruction performed ≤ 3 months post injury (OR 1.65, 95% CI: 1.32–2.06); (6) female sex (OR 1.35, 95% CI 1.14–1.61); and (7) concomitant meniscal injury (OR 1.21, 95% CI 1.03–1.42). The following two factors were associated with decreased odds of a subsequent C-ACL injury: 1) decreased intercondylar notch width/width of the distal femur ratio (OR 0.43, 95% CI 0.25–0.69) and 2) concomitant cartilage injury (OR 0.83, 95% CI 0.69–1.00). There were no associations between the odds of sustaining a C-ACL injury and smoking status, pre-injury activity level, playing soccer compared to other sports or timing of return to sport. No studies of neuromuscular function in relation to risk of C-ACL injury were eligible for meta-analysis according to our criteria. Conclusion This review provides evidence that demographic factors such as female sex, young age (≤ 18 years) and family history of ACL injury, as well as early reconstruction and returning to a high activity level increase the risk of C-ACL injury. Given the lack of studies related to neuromuscular factors that may be modifiable by training, future studies are warranted that investigate the possible role of factors such as dynamic knee stability and alignment, muscle activation and/or strength and proprioception as well as sport-specific training prior to return-to-sport for C-ACL injuries. PROSPERO: CRD42020140129.

Dynamic Configuration of Coactive Micropatterns in the Default Mode Network during Wakefulness and Sleep

The default mode network (DMN) is a prominent intrinsic network that is observable in many mammalian brains. However, few studies have investigated the temporal dynamics of this network based on direct physiological recordings. Herein, we addressed this issue by characterizing the dynamics of local field potentials (LFPs) from the rat DMN during wakefulness and sleep with an exploratory analysis. We constructed a novel coactive micropattern (CAMP) algorithm to evaluate the configurations of rat DMN dynamics and further revealed the relationship between DMN dynamics with different wakefulness and alertness levels. From the gamma activity (40-80 Hz) in the DMN across wakefulness and sleep, three spatially stable CAMPs were detected: a common low-activity level micropattern (cDMN), an anterior high-activity level micropattern (aDMN) and a posterior high-activity level micropattern (pDMN). A dynamic balance across CAMPs emerged during wakefulness and was disrupted in sleep stages. In the slow-wave sleep (SWS) stage, cDMN became the primary activity pattern, whereas aDMN and pDMN were the major activity patterns in the rapid eye movement sleep (REM) stage. Additionally, further investigation revealed phasic relationships between CAMPs and the up-down states of the slow DMN activity in the SWS stage. Our study revealed that the dynamic configurations of CAMPs were highly associated with different stages of wakefulness and provided a potential three-state model to describe the DMN dynamics for wakefulness and alertness.Impact StatementIn the current study, a novel coactive micropattern method (CAMP) was developed to elucidate fast DMN dynamics during wakefulness and sleep. Our findings demonstrated that the dynamic configurations of DMN activity are specific to different wakefulness stages and provided a three-state DMN CAMP model to depict wakefulness levels, thus revealing a potentially new neurophysiological representation of alertness levels. This work could elucidate the DMN dynamics underlying different stages of wakefulness and have important implications for the theoretical understanding of the neural mechanism of wakefulness and alertness.

Hemispheric asymmetry in field-aligned and ionospheric horizontal currents from the Swarm satellite measurements

&lt;p&gt;&lt;span&gt;We present statistical investigation of the high-latitude ionospheric current systems in the Northern hemisphere (NH) and Southern hemisphere (SH) during low (Kp &lt; 2) and high (Kp &amp;#8805; 2) geomagnetic activity levels. Nearly &lt;/span&gt;&lt;span&gt;four &lt;/span&gt;&lt;span&gt;years of vector magnetic field measurements are analyzed from the two parallel flying Swarm A and C satellites using the spherical elementary current system (SECS) method. The ionospheric horizontal and field-aligned currents (FACs) for each auroral oval crossing are calculated. The mean values of FACs, as well as the horizontal curl-free (CF) and divergence-free (DF) currents in 1&lt;sup&gt;o&lt;/sup&gt; magnetic latitude by 1 h magnetic local time grid cells,&amp;#160;are calculated for each hemisphere and activity level. To estimate the NH/SH current ratios for the two activity levels, we remove seasonal bias in the number of samples and in the Kp distribution by bootstrap resampling. &lt;/span&gt;&lt;/p&gt;&lt;p&gt;&lt;span&gt;Averaging over all seasons, we found that for the low activity level the currents in the NH are stronger than in the SH by 12 &amp;#177; 4 % for FAC, 9 &amp;#177; 2% for the horizontal CF current and 8 &amp;#177; 2% for the horizontal DF current. During the high activity level, the hemispheric differences are not statistically significant. &lt;/span&gt;&lt;/p&gt;&lt;p&gt;&lt;span&gt;When making the statistical analysis for the four seasons separately, we find a seasonal dependence in the hemispheric asymmetry. During low Kp conditions, both FACs and horizontal currents are larger in the NH than SH with the largest difference observed in winter. In winter, the currents in the NH are larger than the SH by 21 &amp;#177; 5 % &amp;#160;for FAC, 14 &amp;#177; 3% for the horizontal CF current and 10&amp;#177;3% &amp;#160;for the horizontal DF current. During the high activity level, the asymmetry is smaller compared to the low activity level with the largest and smallest hemispheric differences observed in autumn and summer, respectively. In autumn, the currents in the NH are larger than the SH by 8 &amp;#177; 5% &amp;#160;for FAC, 9 &amp;#177; 2% &amp;#160;for the horizontal CF current and 8 &amp;#177; 3% &amp;#160;for the horizontal DF current. Interestingly, during high Kp conditions, the NH/SH ratio of horizontal current is &gt;1 in autumn and &lt;1 in spring. &lt;/span&gt;&lt;/p&gt;&lt;p&gt;&lt;span&gt;The physical mechanism producing the hemispheric asymmetry is not known. One hypothesis is that the local ionospheric conditions, such as magnetic field strength or daily variations in insolation may play a role. We present preliminary results indicating that only a small part of the seasonal dependence in the NH/SH total current ratios can be explained by variations in the background conductances caused by solar irradiance and affected by local hemispheric values of the magnetic field.&lt;/span&gt;&lt;/p&gt;&lt;p&gt;&amp;#160;&lt;/p&gt;&lt;p&gt;&amp;#160;&lt;/p&gt;&lt;p&gt;&amp;#160;&lt;/p&gt;

About neural network modeling and prediction epizootic tulartmia at tula state territory

Epizootical monitoring of natural tularemia focuses for 1976-4014 years showed that main carrier of infection is common vole (Microtus arvalis). For the part of all obtained cultures of tularemia bacteria common vole has 51,2%. Its strength and infection can change. At period for 1976-2006 years, natural tularemia focuses were at high activity level, but since 2007 year for now, they are at low activity level. By using method artificial neural network made mathematical model of prediction epizootical tularemia; found that climatic factors (downfalls, temperature, snow depth) playing main role at processes reduction activity and strength of natural tularemia focuses, for example, tularemia epizootia can happen in case of froze December, numerous downfalls and high snow depth.

Cartilage Repair Approach and Treatment Characteristics in the Knee Joint

Objectives: To determine the approaches of Turkish Orthopaedic and Traumatology specialists towards the treatment of isolated focal cartilage lesions in the knee joint. Methods: An online questionnaire consisting of 21 questions was prepared and sent to a sample group comprising members of the Turkish Orthopaedics and Traumatology Association (TOTBID) and the Turkish Sports Injuries Arthroscopy and Knee Surgery Association (TUSYAD). The responses of 129 members were evaluated. Results: Of the total respondents to the questionnaire, approximately 1/3 worked in a private hospital, 1/3 in a university, 15% in a state hospital and 13% in a training and research hospital. An arthroscopic approach was applied fewer than 50 times per year by 20% of respondents, 50-100 times by 40%, 100-200 times by 24% and more than 200 times by 17%. The upper age limit for surgical repair of cartilage was reported as 50 years by 52% and 40 years by 25%. Similarly, the body mass index (BMI) upper limit was stated as below 30kg/m2 by 58% and below 25kg/m2 by 22%. The best results were thought to come from femoral condyle lesions by 85% of the surgeons. In patients with high activity expectations, the most frequently applied methods were 60% microfracture and 40% mosaicplasty. For lesions between 2.5 and 4cm2 in size, mosaicplasty was applied most often, followed by matrix-supported chondrocyte implantation. In lesions larger than 4cm2, MACI was the most common procedure. Although 70% of surgeons had never applied the matrix-supported microfracture method, 30% considered that it could be a choice for individuals with a high activity level. A return to sports following cartilage repair was accepted as 6 months for microfracture (86%), 9 months for mosaicplasty (63%), and 12 months for matrix-supported autologous chondrocyte implantation (73%). Conclusion: As there was a similar distribution of experienced and less experienced surgeons among the respondents, the results obtained from the questionnaire are significant in terms of reflecting the general perspective in the country. That mosaicplasty was the first choice for lesions over 2.5cm2 in individuals with a high activity level may be related to poor long-term results of microfracture in large defects. Although it is not widely used in our country and social security repayments are limited, it was noteworthy that for defects over 4cm2, the first choice was second generation autologous chondrocyte implantation. Similarly, it is significant that a third of the surgeons stated matrix-supported microfracture as a choice for high activity patients, although it is not often applied. Decision makers in institutions making repayments should take into account that large defects require methods which are relatively more expensive and need high technology. The results obtained here of an upper age limit of 50 years and BMI below 30kg/m2 for cartilage repair are consistent with literature. A return to sports is planned as 6 months at the earliest and a longer period after more complex surgery.