An Improved Backoff Scheme and Its Performance Analysis for Full Duplex MAC Protocols in VLC Networks.

IEEE 802.15.7 Visible Light Communication (VLC) networks suffer from performance degradation caused by the hidden device collisions due to the directional transmission with narrow beamwidth. One of the solutions for mitigating the hidden device collisions is to employ a full-duplex transmission technique. As a side effect of the full-duplex transmission in the VLC networks, however, the data-packet discard due to the retransmission limitation occurs frequently in the networks. This paper proposes an improved backoff scheme and its performance analysis to suppress the packet discard. The proposed backoff scheme increases the Backoff Exponent (BE) and the Number of Backoff stage (NB) in IEEE 802.15.7 only when the data packet transmission fails. To evaluate the system performance theoretically, this paper also provides the Markov-chain model for channel access with the proposed scheme. The performance evaluations through simulation and theoretical analysis show the effectiveness of the proposed scheme.

A PRELIMINARY STUDY OF INCREASING SELF-EFFICACY IN JUNIOR HIGH SCHOOL STUDENTS: INDUCED SUCCESS AND A VICARIOUS EXPERIENCE.

Bandura's self-efficacy source hypothesis was examined by testing whether success and a vicarious experience of success would enhance self-efficacy among 159 7th graders (81 boys, 78 girls). Unknown to themselves or their classmates, 20 students (Success condition) were presented with easier anagram tasks, allowing them to outperform their 60 classmates (Control condition). The Success and Control students had been paired with classmates (Cheerers; Vicarious condition) who were to cheer on their partners during the task. The participants rated their self-efficacy for the anagram task before and after the performance. The results showed that successful performance significantly promoted the self-efficacy of Success students. However, the cheerers of Success students did not have increased self-efficacy through the vicarious success experience.

Co-witness auditory memory conformity following discussion: a misinformation paradigm.

Twenty-four Japanese undergraduate pairs (12 male and 12 female pairs) participated as witnesses to a simulated criminal event. Although the witness pairs watched the same video together, through wireless headphones they experienced two different auditory versions with four differing items without being aware of the discrepancies. After the presentation, the witnesses were led to discuss six items, including two critical ones they had heard differently and another four they had heard in common. Witness memory performance was assessed individually with multiple-choice questionnaires in three sessions: before the discussion, after the discussion, and 1 week later. The results showed that participants tended to conform to their co-witness more often on the discussed items than on the not-discussed items. Source monitoring analyses on the four critical items revealed that even those participants who conformed were mostly cognizant of the source of their information just after the discussion, but they were prone to source-monitoring errors a week later.

Reappraisal of serum retinol-binding protein as a surrogate marker for retinol and discovery of a novel retinol estimation formula.

BACKGROUND & AIMS: Serum retinol (ROH) is commonly used for population level assessment of vitamin A status. High-performance liquid chromatography (HPLC) is considered most accurate method for measuring ROH. However, with the technical difficulty of using HPLC for routine assays, serum retinol-binding protein (RBP) measured by immunological assays is expected to be a surrogate marker for ROH, with reports of a close correlation between serum RBP and ROH. Nevertheless, RBP is not commonly tested to assess vitamin A status with concerns over RBP alterations under various physiopathological conditions. Thus, we reappraised the extent to which RBP could be used as a surrogate marker in representative disorders that alter serum RBP levels. As a related marker, diagnostic utility of transthyretin (TTR) was also evaluated. METHODS: To evaluate the reliability of ROH and RBP assays, specimen stability was assessed in terms of (1) storage at 25, 4, -20, and -80 °C for 1-28 days, (2) five-cycle freeze-thawing, and (3) fluorescent light exposure for 1-14 days. Sources of variation (sex, age, body mass index [BMI], and drinking habits) and reference intervals for ROH, RBP, and TTR were determined in 617 well-defined healthy individuals. To investigate the influence of disorders that affect serum RBP, patients with five diagnostic groups were enrolled: 26 with chronic kidney disease (CKD); 13 with various malignancies in advanced stages (AdM), 12 with acute bacterial infections (ABI), 6 with liver cirrhosis (LC), and 26 with simple obesity (BMI ≥ 27 kg/m2). RESULTS: The stability of RBP and ROH in serum was confirmed under all conditions. In healthy individuals, serum ROH, RBP, and TTR were appreciably high in males with a slight increase in proportion to age and BMI. The major-axis regression line between RBP (x) and ROH (y) in healthy individuals was y = x, with a correlation coefficient of 0.986. In the LC, AdM, and ABI groups, similar strong correlations were observed; however, the regression lines were shifted slightly rightward from the healthy group line, indicating a positive bias in estimating ROH. Interestingly, the same analyses between TTR and ROH revealed similar strong linear relationships in all groups; however, the regression line of each group showed a leftward (opposite) shift from the healthy group line. Based on these observations, we developed a novel regression model composed of RBP and TTR, which gave much improved accuracy in estimating ROH, even under these pathological conditions. CONCLUSIONS: The perfect RBP-ROH correlation in healthy individuals indicates the utility of RPB as a surrogate marker for ROH. Nevertheless, under RBP-altered conditions, a slight overestimation of ROH is inevitable. However, when the TTR was tested together, the bias can be corrected almost perfectly using the novel ROH estimation formula comprising RBP and TTR.

An implicit assessment of the effect of artificial cheek raising: when your face smiles, the world looks nicer.

Experiments were conducted with 80 undergraduate participants (52 men and 28 women) to examine whether the sensation of having the cheeks lifted or pulled down would elicit different responses in an implicit association test. Implicit emotional responses were measured for two facial feedback conditions by utilizing a modified Affect Misattribution Procedure. The participants wore one of two types of simple devices designed to either raise or lower the cheeks, and rated neutral targets preceded by three types (positive, neutral, or negative) of prime photos. The results showed that the participants whose cheeks were raised tended to rate the targets statistically more positively than did those whose cheeks were lowered.

Asymmetrical drawing patterns on the temples by left-handers.

Twenty-three Japanese genuine left-handers were selected by a Laterality Quotient scale and asked to draw the letter S on their own temples and foreheads. The way they drew on the temples showed an asymmetry that was the mirror reversal of that of right-handers, as found in a previous study. Left-handers drew a reversed letter S on their right temple much more often than on the left temple, whereas right-handers drew them in reverse more often on the left temple. They also drew it in reverse on the forehead irrespective of their handedness.

Reading words with jumbled characters in Japanese.

Rayner, et al. (2006) was replicated with 36 Japanese undergraduates who read Japanese sentences in which characters were transposed in one word at the beginning, middle, or end. The same pattern of reading delays in relation to transposition location was found but in smaller magnitude. Transposition of characters at the beginning of words caused the largest delay in reading.

Biological sources of variations of tartrate-resistant acid phosphatase 5b in a healthy Japanese population.

BACKGROUND: Tartrate-resistant acid phosphatase 5b (TRACP5b) is a bone resorption marker that is mainly used in clinical management of osteoporosis. For proper interpretations of test results for serum TRACP5b, we explored their biological sources of variation, esp. age-related changes, and associations with other bone-related markers in healthy Japanese adults. METHODS: During the 2009 East-Southeast Asian multicentre study for determination of reference intervals, 72 major laboratory tests were measured by centralized assays in 3541 well-defined healthy volunteers. The current study included 1980 test results in Japanese subjects for five bone-related markers: TRACP5b, bone alkaline phosphatase, intact parathyroid hormone, calcium and inorganic phosphate. Information on sources of variation, including body mass index, smoking habits and ABO-blood group, were obtained from a health status questionnaire. RESULTS: Gender-specific profiles of age-related changes were observed for each parameter. Increased values starting from 40 years of age in females were most prominent for TRACP5b, followed by bone alkaline phosphatase and inorganic phosphate. TRACP5b in males decreased with body mass index, bone alkaline phosphatase and TRACP5b were higher in blood type-O subjects, especially in males. TRACPT5b was closely correlated with bone alkaline phosphatase, and moderately correlated with adjusted calcium and inorganic phosphate, especially in females aged ≥45 years. Reference intervals for each analyte were determined parametrically based on gender and age. CONCLUSIONS: This study elucidated sources of variation of TRACP5b and related bone markers in healthy Japanese subjects and demonstrated a specific age profile for each marker. These results are of relevance for better clinical usage and interpretations of serum levels of bone markers.

No need to fake it: reproduction of the Asch experiment without confederates.

In the present experiment, we replicated Asch's seminal study on social conformity without using confederates. We adapted a presentation trick in order to present two different stimuli secretly to groups of participants to create minorities and majorities without utilizing confederates. One hundred and four Japanese undergraduates (40 men and 64 women) carried out Asch-equivalent tasks in same-sex groups of four. In each group, we adapted the fMORI Technique to present the tasks such that one person (minority participant) observed different stimuli than the other three people (majority participants). The same nine stimulus sets that Asch had used were carefully reproduced as PowerPoint slides and projected onto a half-transparent screen. As for the critical tasks, the top part of the standard lines appeared in either green or magenta so that two groups of participants would see them differently when they wore two types of polarizing sunglasses that filtered either green or magenta to make the lines appear longer or shorter. A post-experimental questionnaire confirmed that no participant among either the minority or majority viewers noticed the presentation trick. The results showed that, in line with Asch's basic findings, the minority women participants conformed to the majority. However, our study produced two different results: While minority women conformed, minority men did not. Contrary to Asch's findings, the frequency of conformity of minority participants was almost the same regardless of whether the majority answered unanimously or not.

Examination of the passive facial feedback hypothesis using an implicit measure: with a furrowed brow, neutral objects with pleasant primes look less appealing.

98 undergraduates (54 men, 44 women) participated in an experiment to examine whether having an artificially furrowed brow would have an effect on participants' subjective impression of perceived targets. An elastic adhesive bandage was either stretched to create furrows on the brow when it retracted, or not stretched so as to avoid creating wrinkles. While wearing the bandages, the participants rated their impressions of neutral targets preceded by agreeable, disagreeable, or neutral primes in a modified Affect Misattribution Procedure. The results showed that participants with artificially furrowed brows tended to rate the neutral targets preceded by agreeable primes less favorably than did the control participants, while both groups rated similarly the targets preceded by disagreeable primes.

Evidence for the efficacy of the MORI technique: viewers do not notice or implicitly remember details from the alternate movie version.

The MORI technique provides a unique way to research social influences on memory. The technique allows people to watch different movies on the same screen at the same time without realizing that each of them sees something different. As a result, researchers can create a situation in which people feel as though they share an experience, but systematic differences are introduced into their memories, and the effect of those differences can be tracked through a discussion. Despite its methodological advances, the MORI technique has been met with criticism, mostly because reviewers are worried that the MORI technique might not completely block the alternate movie version from view, leading people in these studies to see their partner's version of the movie as well as their own. We addressed these concerns in two experiments. We found no evidence that subjects noticed the alternate movie version while watching a movie via the MORI technique (Experiment 1) and no evidence that subjects remembered details from the alternate movie version (Experiment 2). Taken together, the results provide support for the MORI technique as a valuable research tool.

Another test of the passive facial feedback hypothesis: when your face smiles, you feel happy.

88 undergraduates (44 men, 44 women) participated in an experiment to examine whether the cutaneous sensation of having the cheeks lifted would cause a feeling of happiness. Two types of paired adhesive bandages connected with rubber bands were prepared and used either to raise or lower the cheeks. While the bandages were applied, the participants rated their feelings. The results showed that 50 participants felt happiness when their cheeks were lifted, statistically significant compared to the 27 who felt sadness. They confirmed the hypothesis that people may feel happy when their cheeks are lifted upward.

Biological properties of crosslinked salmon collagen fibrillar gel as a scaffold for human umbilical vein endothelial cells.

Collagen derived from chum salmon (Oncorhynchus keta) was crosslinked with 1-ethyl-3-(3-dimethylaminopropyl)-carbodiimide (EDC) during collagen fibrillogenesis and applied to an in vitro cell culture to evaluate its potential use as a scaffold for vascular tissue engineering. Human umbilical vein endothelial cells (HUVEC) were cultured on the crosslinked salmon collagen fibrillar gel (EDC-SC gel), and their growth rates and production levels of cytokines, including platelet-derived growth factor-BB and von Willebrand factor, were measured. Comparison was also made with bovine collagen gel crosslinked with EDC (EDC-BC gel). The growth and cytokine production of the HUVEC cultured on the EDC-SC gel were higher than those on the EDC-BC gel. In addition, HUVEC were found to attach to the EDC-BC gel through alpha2beta1 integrin for native collagen, whereas they attached to the EDC-SC gel through alphavbeta3 integrin for denatured collagen as well as the alpha2beta1 integrin, indicating that HUVEC recognized denatured domains in the EDC-SC gel. In conclusion, the EDC-SC gel can be used as a scaffold to support HUVEC growth, although the integrin-mediated attachment manner differs between the two gels.

Conformity among cowitnesses sharing same or different information about an event in experimental collaborative eyewitness testimony.

Using the Mori technique in which two different movies presented on the same screen were viewed separately by two groups without their noticing the duality, two experiments were carried out with 138 undergraduates in groups of varying sizes to examine the effects of cowitnesses with the same or different information on these witnesses' memory distortion. Exp. 1 investigated the cowitness effects in a one-versus-two situation, while Exp. 2 investigated the effects in a two-versus-two situation. Analysis showed isolated eyewitnesses who had no supporting cowitnesses changed their minds more frequently toward the majority and, when they had a cowitness who shared the same information, they tended to stick to their original reports even after being confronted with conflicting information in a discussion.

Imaging Ca2+ Concentration and pH in Nanopores/Channels of Protein Crystals.

Protein crystals are nanoporous materials. Despite this important characteristic, little is known about the conditions in the pores, also called channels. Here, we describe a method to study the calcium concentration and pH in the nanopores of thaumatin and lysozyme crystals. We load the crystal nanopores with fluorescent indicators and then perfuse the crystals with solutions of different calcium concentrations and pH while reading out the crystal's fluorescence intensity with confocal microscopy. By calibrating the fluorescence signal, we can determine the calcium concentration and pH in the nanopores. For the pH in thaumatin nanopores measured with the ratiometric pH sensor SNARF-1, we find a -0.7 pH shift compared to the bath pH corresponding to a fivefold higher proton concentration. This is similar to the -0.3 pH shift found in lysozyme nanopores. With single-wavelength probes, we find that the calcium concentration in thaumatin crystal nanopores is the same as in the bath, whereas it is 0.24 times lower in lysozyme nanopores. Summarizing, our experiments show that calcium concentration and pH in the nanopores of protein crystals can deviate significantly from that in the bath. In general, the described method can be applied for testing a wide range of ion or small-molecule concentrations in transparent nanoporous materials not only with ratiometric but also with single wavelength fluorescent indicators.

In vitro growth and differentiated activities of human periodontal ligament fibroblasts cultured on salmon collagen gel.

Marine-derived collagen is expected to be a much safer alternative to calf collagen, which in medical applications carries the risk of bovine spongiform encephalopathy. In this study, acid-soluble collagen was extracted from salmon skin and crosslinked with 1-ethyl-3-(3-dimethylaminopropyl)-carbodiimide during fibril formation to produce a crosslinked salmon collagen (SC) gel. The growth rates and the differentiated functions of human periodontal ligament fibroblasts (HPdLFs) cultured on the SC gel were investigated. Growth was faster on the SC gel than on porcine collagen (PC) gel. In addition, the HPdLFs cultured on the SC gel exhibited higher alkaline phosphatase (ALP) activity than those cultured on the PC gel. Quantitative RT-PCR revealed higher mRNA expression of type I collagen, ALP, and osteocalcin in the HPdLFs cultured on the SC gel. HPdLFs had a flat shape on the SC gel and a spindle shape on the PC gel, as revealed by observation with scanning electron microscopy and immunostaining with cytoskeletal protein and vinculin. The results showed that HPdLFs could grow and show highly differentiated activity on the SC gel as well as on the PC gel.

A test of the passive facial feedback hypothesis: we feel sorry because we cry.

Undergraduates, 61 men and 52 women, participated in pairs in an examination of whether simulated tearing of the eyes would cause sadness. In order to simulate the experience of tearing up, about 0.2 ml of water was dropped on the cheek near the lacrimal duct of both eyes of each participant, who then rated subjective feeling on a 7-point scale. 53.8% of participants reported sadness along with the simulated tearing, which was statistically larger than the 28.6% who reported cheerfulness.

A global multicenter study on reference values: 1. Assessment of methods for derivation and comparison of reference intervals.

OBJECTIVES: The IFCC Committee on Reference Intervals and Decision Limits coordinated a global multicenter study on reference values (RVs) to explore rational and harmonizable procedures for derivation of reference intervals (RIs) and investigate the feasibility of sharing RIs through evaluation of sources of variation of RVs on a global scale. METHODS: For the common protocol, rather lenient criteria for reference individuals were adopted to facilitate harmonized recruitment with planned use of the latent abnormal values exclusion (LAVE) method. As of July 2015, 12 countries had completed their study with total recruitment of 13,386 healthy adults. 25 analytes were measured chemically and 25 immunologically. A serum panel with assigned values was measured by all laboratories. RIs were derived by parametric and nonparametric methods. RESULTS: The effect of LAVE methods is prominent in analytes which reflect nutritional status, inflammation and muscular exertion, indicating that inappropriate results are frequent in any country. The validity of the parametric method was confirmed by the presence of analyte-specific distribution patterns and successful Gaussian transformation using the modified Box-Cox formula in all countries. After successful alignment of RVs based on the panel test results, nearly half the analytes showed variable degrees of between-country differences. This finding, however, requires confirmation after adjusting for BMI and other sources of variation. The results are reported in the second part of this paper. CONCLUSION: The collaborative study enabled us to evaluate rational methods for deriving RIs and comparing the RVs based on real-world datasets obtained in a harmonized manner.

Elicitation of spontaneous mirror reversal drawing on the forehead.

32 Japanese participants drew symmetrical and asymmetrical letters on their own foreheads. By observing their drawing strokes, it was judged that 29 of them drew symmetric letters in reverse, that is, as if these were viewed from inside the head. However, 14 of these 29 seemed to have noticed their reversed perception because they drew asymmetric letters intentionally reversed so they would appear correct when viewed from outside. Only three participants drew the letters in a normal way irrespective of the letter symmetry.

Comments on defining adolescence.

Aspects of a definition for two characteristics of adolescence, being capable of doing something or not and having the right to do it, are proposed since adolescence is a period when a person is capable of but without the right to do something.