Effectiveness of Link Prediction for Face-to-Face Behavioral Networks

Research on link prediction for social networks has been actively pursued. In link prediction for a given social network obtained from time-windowed observation, new link formation in the network is predicted from the topology of the obtained network. In contrast, recent advances in sensing technology have made it possible to obtain face-to-face behavioral networks, which are social networks representing face-to-face interactions among people. However, the effectiveness of link prediction techniques for face-to-face behavioral networks has not yet been explored in depth. To clarify this point, here we investigate the accuracy of conventional link prediction techniques for networks obtained from the history of face-to-face interactions among participants at an academic conference. Our findings were (1) that conventional link prediction techniques predict new link formation with a precision of 0.30–0.45 and a recall of 0.10–0.20, (2) that prolonged observation of social networks often degrades the prediction accuracy, (3) that the proposed decaying weight method leads to higher prediction accuracy than can be achieved by observing all records of communication and simply using them unmodified, and (4) that the prediction accuracy for face-to-face behavioral networks is relatively high compared to that for non-social networks, but not as high as for other types of social networks.     

Development and ultrastructure of the thickened serosa and serosal cuticle formed beneath the embryo in the stonefly Scopura montana Maruyama, 1987 (Insecta,Plecoptera, Scopuridae)

We aimed to describe the development and ultrastructure of the thickened serosa and serosal cuticle formed beneath the embryo of Plecoptera, using Scopura montana of Scopuridae as a euholognathan representative. Using transmission electron microscopy, we found that the egg membranes were composed of a thick exochorion, a thicker endochorion consisting of two sublayers, and an extremely thin vitelline membrane. The egg membrane construction represents a groundplan feature of the euholognathan egg membranes. The serosa converges beneath the embryo to form a thickened serosa, comprising cells in a radial arrangement, in association with the formation of the amnioserosal fold. The thickened serosa then deposits the thickened serosal cuticle, consisting of four layers differing in fine structure and electron density. After achieving its secretory function, the thickened serosa then disintegrates, and the liberated serosal cells float for a short period in the peripheral region of the egg inside. Collectively, our findings should provide the basis for further characterization of the serosal structures concerned, but we were unable to corroborate previous studies assigning the thickened serosa and serosal cuticle in Plecoptera to the water absorption function.     

Relationships between daytime sleepiness and sleep quality,duration, and phase among school-aged children: a cross-sectional survey

A cross-sectional survey was conducted to simultaneously evaluate sleep quality, duration, and phase in school-aged children and correlations between each dimension of sleep and daytime sleepiness were comprehensively examined. A cross-sectional survey was conducted with school-aged children enrolled in four public elementary schools in Joetsu city, Niigata prefecture in Japan (n = 1683). Among the collected responses (n = 1290), 1134 valid responses (547 boys and 587 girls) were analyzed (valid response rate was 87.90%). Data on daytime sleepiness, sleep quality (problems in sleeping at night), sleep duration (the average sleeping time during a week), and sleep phase (sleep timing: bedtime and rising time on weekdays, and sleep regularity: differences in bedtime and rising time between on weekdays and weekends) were collected. The results of multivariate logistic regression analysis indicated that the following dimensions were significantly correlated with daytime sleepiness: the decline in sleep quality [adjusted odds ratio (AOR) = 2.62, 95% confidence interval (CI) = 1.71–4.00], bedtime after 21:30 on weekdays (AOR = 1.58, 95% CI = 1.15–2.18), bedtime delay on weekends, compared to weekdays (AOR = 1.75, 95% CI = 1.27–2.41), and bedtime advance on weekends, compared to weekdays (AOR = 3.33, 95% CI = 1.78–6.20). Sleep dimensions that significantly affected daytime sleepiness in school-aged children are sleep quality, bedtime-timing, and regularity of bedtime. It is important to detect problems in night sleep and establish treatments, as well as to provide support for early bedding on weekdays and for a regular bedtime both on weekdays and on weekends to prevent daytime sleepiness in school-aged children.

     

Physicochemical and immunochemical characterization of salicylate 5-hydroxylase,m-hydroxybenzoate 6-hydroxylase and p-hydroxybenzoate 3-hydroxylase from Rhodococcus erythropolis

Salicylate 5-hydroxylase (SAL5H), m-hydroxybenzoate 6-hydroxylase (MHB6H), and p-hydroxybenzoate 3-hydroxylase (PHB3H) from Gram-positive Rhodococcus erythropolis strain S1 were characterized physicochemically and immunochemically. The subunit size and amino acid composition of SAL5H, MHB6H, and PHB3H from strain S1 showed properties similar to those of other flavin-containing aromatic compound monooxygenases such as p-hydroxybenzoate hydroxylase and salicylate 1-hydroxylase (SAL1H), belonging to p-hydroxybenzoate hydroxylase-class, except for homotetrameric structure and cofactor specficity. The N-terminal amino acid sequence of MHB6H from strain S1 indicated significant similarity of ADP-binding region in the N-terminal portion of the enzyme with that known for SAL1H from Pseudomonas putida. Immunochemical properties, determined while conducting serological experiments, showed SAL5H and MHB6H from strain S1 to be immunologically different from PHB3H from strain S1, while SAL5H and MHB6H to apparently share partial antigenic determinants.     

Prion Protein Is Necessary for Latent Learning and Long-Term Memory Retention

1. The cellular prion protein, designated PrP^c, is a key molecule in the prion diseases but its physiological function remains unknown. To elucidate whether PrP^c plays some role in the central nervous system, we established a line of mice in which the PrP gene had been disrupted and subsequently conducted long-term observations.2. Performance in latent learning and passive avoidance was evaluated using water-finding and step-through tests, respectively.3. PrP ^–/– mice showed impaired performance in the water-finding test, indicating a disturbance in latent learning, at 23 weeks of age. In the step-through test, although the PrP ^–/– mice showed normal learning ability and short-term memory retention, they evidenced a significant disturbance in long-term memory retention.4. These results indicate that PrP^c is needed for certain types of learning and memory and that the loss of function of this protein may contribute to the pathogenesis of prion diseases.     

Revised sequence of the nusA gene of Escherichia coli and identification of nusA11 (ts) and nusA1 mutations which cause changes in a hydrophobic amino acid cluster

Summary The mutant nusA DNAs (nusA11 and nusA1) were sequenced. Single base substitutions caused by these mutations were found in the coding region of nusA. The nusA11 mutation, which is conditionally lethal, substituted Thr for the 181st Ala. Also, nusA1, which restricts growth, substituted Ala for the 183rd Ser. These two positions were located in the same hydrophobic amino acid cluster. This cluster seemed to be an essential region in the functional domain of NusA. In the course of these experiments, several mistakes in the published nusA nucleotide sequence were found. These errors are revised in this article. The molecular weight of NusA is accordingly revised to 54,430.     

Phylogenomics changes our understanding about earwig evolution

Earwigs are one of the comparatively species-poor insect orders. Although various aspects of the phylogeny of this lineage are poorly understood, before the present study, there was a general consensus that Dermaptera comprises two major lineages: the paraphyletic Protodermaptera or ‘lower earwigs’ and the monophyletic Epidermaptera or ‘higher earwigs’, which are nested within the former. Our phylogenomic study based on the analysis of 3247 nuclear single-copy genes reverses these relationships by placing monophyletic Protodermaptera within paraphyletic Epidermaptera. This phylogenetic reversal among the major earwig lineages is not contradicted by morphological arguments but results in far-reaching reinterpretations of the dermapteran ground plan. Within Dermaptera, Apachyidae form the sister group to the remaining earwigs which might imply that social behaviour is not part of the earwig ground plan. Our results corroborate the monophyly of Eudermaptera within Epidermaptera and the paraphyly of several traditional families. The monophyly of Protodermaptera is supported by molecular and morphological evidence, although the exact position of Karschiellidae which were not included in the molecular dataset cannot be determined.     

Terrestrial biomass resources in Japan

Japan, a small and mountainous country with little fossil fuel, has a variety of biomass resources that could be used to derive energy sources. Many of these resources could be obtained from currently unutilized or waste portions of other products. Important sources of biomass include woodlands, native grasslands, wastelands, and farms. Although much biomass is seasonal and difficult to handle, continued technological advances may allow utilization while at the same time improving the environment.     

Fluorescent quenching-based quantitative detection of specific DNA/RNA using a BODIPY® FL-labeled probe or primer

We have developed a simple method for the quantitative detection of specific DNA or RNA molecules based on the finding that BODIPY^® FL fluorescence was quenched by its interaction with a uniquely positioned guanine. This approach makes use of an oligonucleotide probe or primer containing a BODIPY^® FL-modified cytosine at its 5′-end. When such a probe was hybridized with a target DNA, its fluorescence was quenched by the guanine in the target, complementary to the modified cytosine, and the quench rate was proportional to the amount of target DNA. This widely applicable technique will be used directly with larger samples or in conjunction with the polymerase chain reaction to quantify small DNA samples.