The influence of regional processes, such as dispersal, on ecological communities has been the focal point of considerable ecological research. Evidence has shown that dispersal can impact community composition through interactions with predation, the introduction of keystone species, and maintenance of species lost due to competitive exclusion. Ecological communities can be characterized by several metrics including species richness, diversity, evenness, abundance and species co-occurrence patterns. Negative species co-occurrence patterns have historically been attributed to competitive interactions between species causing pairs of species to never co-occur. However, little attention has been paid to the contribution of dispersal on species co-occurrence patterns. I have experimentally investigated the influence of dispersal on species co-occurrence patterns in addition to local species richness, total species abundance, evenness, and Simpson’s diversity. Local species richness significantly increased with dispersal, with variation in total local richness being mainly attributed to differences in the rotifer community. Local diversity, total abundance, and evenness were not significantly influenced by changes in the level of dispersal. Species co-occurrence patterns were greatly affected by changes in dispersal, with negative species co-occurrence patterns peaking at intermediate levels of dispersal. The potential for dispersal to increase the number of rare species within a community suggested that the presence of rare species could be behind the changes in the co-occurrence patterns between dispersal treatments. The effect size of the co-occurrence tests increased with the removal of rare species in the intermediate dispersal treatment and decreased in the remaining dispersal treatments. Likely, through mass effects, the presence of rare species, and the establishment of keystone predators changes in the level of dispersal strongly influenced species co-occurrence patterns. I conclude that external processes, like dispersal, can influence species co-occurrence patterns and that caution should be taken when interpreting the mechanisms driving species co-occurrence patterns across landscapes. / Thesis (Master, Biology) -- Queen's University, 2011-09-28 15:00:40.972

The author presents an analysis of how speakers establish references in conversation. Further, this paper focuses on what words of a reference are conventionalized as speakers coordinate multiple times. The author explores how the co-occurrence of the reference terms with the referent can be a good predictor of what words are conventionalized over time. In order to study this, the author created an online version of the reference game from Clark and Wilkes-Gibbs (1986) experiment, where a matcher and director must describe a set of ambiguous shapes to each other many times. By creating an online version of this reference game the author was able to gather significantly more data and analyze the data with computational tools. Results prove that co-occurrence is a useful predictor of terms which are conventionalized, providing a first step for accounting for statistical inference in the process of conventionalization.

Parasite-host systems provide excellent opportunities to explore ecological dynamics such as competition, competitive exclusion, and co-occurrence. The distribution of streblid bat flies on their host bats were examined for patterns of species co-occurrence and to understand mechanisms driving these patterns. The purpose of this study was to determine patterns of co-occurrence among individuals of different Neotropical bat fly species. After establishing patterns of co-occurrence, tests on whether variation in fly morphology was linked to observed patterns of co-occurrence were performed. Co-occurrence patterns were determined using null model analyses, and a predominant pattern of aggregation was detected. To examine the relationship between co-occurrence and morphology, geometric morphometric analyses were performed to compare morphologies of co-occurring individuals of different species. Examination of ratios of species-pairs with significant differences in their morphology relative to speciespairs without significant differences resulted in both insight and more questions. Species segregation may result from morphological similarity between co-occurring streblid species, potentially reflecting historical niche overlap leading to competitive exclusion of one species from infesting the host individual. Aggregation of multiple streblid species however, does not appear to be due to differences in morphology. Results also indicate that explanations of co-occurrence patterns are not straightforward, and that multiple mechanisms may underlie patterns of co-occurrence. These results underscore important potential connections between morphology and patterns of co-occurrence, but future research is needed to verify these conclusions and examine other possible contributing mechanisms to patterns of co-occurrence in this biological system.

Three experiments were conducted to examine the effect of association strength on TOT (tip-of-the-tongue states) and recall. Two hundred nineteen undergraduate students studied pictures and names of 24 imaginary animals that were presented on a large computer screen. The strength of association between the cue and target was manipulated by varying the number of times the picture and the name were presented simultaneously, while keeping the number of presentations for each picture or the target constant across conditions. After the study phase, participants were cued by each picture to recall the imaginary animal names. Participants were asked to rate their strength of TOT on a scale ranging 0 to 3 for each item if they could not think of the name at the moment. Participants also made subjective judgments as to how many times they saw the picture and name of the animal co-occur on the same screen at the study phase, and then they performed a recognition test at the end. The results indicated that the frequency and strength of TOTs linearly increased as a function of number of co-occurrences; the correlation between TOT strength and the participants?? subjective estimation of number of co-occurrences was greater than the correlation between TOT strength and the actual number of co-occurrences. This pattern of results was found even when recall increased along with the increase in number of co-occurrences and was more pronounced particularly when recall was reduced either by interference (Experiment 1) or by increased number of critical items (Experiments 2 & 3) and also by a reduced number of co-occurrence conditions and an increased gap between one level to the next (Experiment 3). Results suggest that an increase in association strength concomitantly increases TOT strength especially when the activation of the target is under threshold for recall and that people may use rules of thumb, or heuristic when they report TOTs by estimating the strength of the cue-target association.

The advantages that a side-scan sonar can offer include large-scale survey areas and high-resolution imagery which can provide the detection and positioning of underwater targets effectively. The purpose of image analysis, classification and positioning in this research was presented by the development of an automated recognition and classification system based on sonographs collected off Kenting area. Major components of the system include gray level co-occurrence matrix method, Baysian classification and cluster analysis. The sonograph classified by the automated recognition and classification system was split into two stages. The first stage divided the seafloor into three categories: (1) Rocky seafloor. (2) Sandy seafloor. (3) Acoustic shadow seafloor. Based on the characteristics of the rocky seafloor, the rocky seafloor was subdivided into five types in the second stage: (1) Flank reef and small independent reef. (2) Smooth reef. (3) Small coral on reef. (4) Coral on independent reef. (5) Large coral on reef. Analysis and proof of the system was conducted by underwater photographs collected off Kenting area in August 4, to 6, 2004. The identification accuracy of the first stage can reach 93% in Shiniuzai area. The characteristic features selected in this research (i.e., entropy and homogeneity) for the classification of various coral reef seafloors was proved adequate and the results was described in map within a Geographic Information System in the second stage. The results of this research illustrated that the rocky area identified in Shiniuzai was 98,863 m2. Due to image resolution restrictions, only 62,199 m2 of the total rocky area could be defined and classified properly. Among them, the flank reef and small independent reef covered an area of 15,954 m2 (26.3%); the smooth reef covered 3,133 m2 (5.0%); the small coral on reef covered 8,021 m2 (12.8%); the coral on independent reef covered 25,504 m2 (40.7%) and the large coral on reef covered 9,587 m2 (15.3%). Key words:side scan sonar,coral reef,gray level co-occurrence matrix

Older adults may be better able to modulate their emotional experiences than younger adults, and thus may recover more quickly from negative stressors. Additionally, older adults may be more likely to experience co-occurrence of negative and positive emotions in the setting of negative stressors, which may facilitate emotion recovery. To date, few studies have investigated the nature of age group differences in spontaneous emotional responses to a standardized stressor. The current study utilizes a laboratory mood manipulation to determine age group differences in emotion recovery in negative and positive affects, as well as age group differences in the co-occurrence of negative and positive affect. Older adults reported greater reactivity in one and greater recovery in two negative affect scales than younger adults; however, these differences did not remain significant when controlling for overall arousal ratings of the mood induction. There were no age group differences in reactivity or recovery of positive affects. Both younger and older adults returned to baseline in negative affects by the end of the recovery period despite age group differences in affect responses and arousal ratings. Older adults reported greater co-occurrence of negative and positive emotions in response to the mood induction as compared to younger adults. Overall, these results provide support for age group similarities in reactivity and recovery in discrete affects, and age group differences in mixed emotion states. Greater co-occurrence appears to reflect greater baseline endorsement of positive affect in older as compared to younger adults. Thus, higher baseline positive affect may create greater opportunities for older adults to experience mixed emotion states, which may in turn serve as an adaptive resource for older adults.

京都大学 / 新制・課程博士 / 博士(医学) / 甲第23373号 / 医博第4742号 / 新制||医||1051(附属図書館) / 京都大学大学院医学研究科医学専攻 / (主査)教授 古川 壽亮, 教授 林 康紀, 教授 髙橋 良輔 / 学位規則第4条第1項該当 / Doctor of Medical Science / Kyoto University / DFAM

Introduction: Research has found extensive similarities between symptoms of gaming disorder/Internet gaming disorder (GD/IGD) and symptoms of other addictive disorders, including the presence of cravings, tolerance, and inability to stop despite adverse consequences (Müller & Montag, 2017). Significant associations between GD/IGD and financial strain, occupational difficulties, sleep deprivation, malnutrition, obesity, and the development and/or exacerbation of other mental illness have been found, contributing to growing concern over the detrimental impact of GD/IGD (Kohorst et al., 2018). Video gaming is also associated with increased use of substances, including nicotine as found in electronic nicotine delivery systems (ENDS; Cranwell et al., 2016). The harmful consequences of ENDS use may exacerbate the health risks associated with GD/IGD, especially in connection to sleep, nutrition, and mental health. There is extensive overlap between the demographic and psychosocial characteristics of typical video gamers and typical users of ENDS, including being young, male, highly impulsive, sensation-seeking, and having a diagnosis of attention-deficit hyperactivity disorder (ADHD), which may account for the rates of concurrent dependence (Von der Heiden et al., 2019; Mathews, 2019). However, definitive characteristics of individuals demonstrating symptoms of both GD/IGD and ENDS dependency remain unknown. The present study aims to explore the demographic and psychological associations of co-occurring symptoms of GD/IGD and ENDS dependency. Method:Participants (n = 2,174) were college students age 18-24 (M=19.25) recruited as part of a multi-university study examining psychological variables within young adults. Participants completed a battery of self-report questions assessing for demographic characteristics, symptoms of ADHD, and level of impulsivity and sensation seeking as measured by the Adult ADHD Self-Report Scale, Brief Sensation Seeking Scale, and Barratt Impulsiveness Scale Version 11, respectively. ENDS dependency was evaluated through the PROMIS E-cigarette Dependence Scale, and GD/IGD was measured by the Video Game Dependency Scale. Pearson correlations, chi-square tests, MANCOVAS, and moderation analyses were used to evaluate this data. Results:Results found that 7.3% of the sample met criteria for probable ENDS dependency, 4.7% of the sample endorsed symptoms of GD/IGD dependency, and 1.4% of the sample endorsed both dependencies. Age, gender, and race/ethnicity were all associated with increased risk of concurrent GD/IGD and ENDS dependency. The moderating effect of ADHD symptoms on the relation between GD/IGD and ENDS dependency was significant, ΔR2 = .067, F(1, 1036) = 24.75, p < .001, indicating that the relation between GD/IGD and ENDS dependency was stronger when participants endorsed more symptoms of ADHD. Impulsivity and sensation seeking also had significant interaction effects on the relation between ENDS dependency and GD/IGD. Conclusion:Ultimately, there is ample evidence that ENDS dependency and GD/IGD occur at significant levels on college campuses. Heightened impulsivity and sensation seeking and the diagnosis of ADHD significantly correspond with increased rates of GD/IGD and ENDS dependency. These results are supported by prior research findings that impulsivity and sensation seeking are risk factors for many behavioral health concerns, including engagement in risky sexual behaviors and substance addiction. Future research examining protective factors and treatment of co-occurring GD/IGD and ENDS dependency is warranted. References: Cranwell, J., Whittamore, K., Britton, J., & Leonardi-Bee, J. (2016). Alcohol and tobacco content in UK video games and their association with alcohol and tobacco use among young people. Cyberpsychology, Behavior and Social Networking, 19(7), 426-434. https://doi.org/10.1089/cyber.2016.0093 Kohorst, M. A., Warad, D. M., Nageswara Rao, A. A., & Rodriguez, V. (2018). Obesity, sedentary lifestyle, and video games: The new thrombophilia cocktail in adolescents. Pediatric Blood & Cancer, 65(7), e27041. Mathews, C. L., Morrell, H. E. R., & Molle, J. L. (2019). Video game addiction, ADHD symptomatology, and video game reinforcement. The American Journal of Drug and Alcohol Abuse, 45(1), 67-76. https://doi.org/10.1080/00952990.2018.1472269 Müller, M., & Montag, C. (2017). The relationship between internet addiction and alcohol consumption is influenced by the smoking status in male online video gamers. Clinical Neuropsychiatry: Journal of Treatment Evaluation, 14(1), 34–43. Von der Heiden, J. M., Braun, B., Müller, K. W., & Egloff, B. (2019). The association between video gaming and psychological functioning. Frontiers in Psychology, 10, 17-31. https://doi.org/10.3389/fpsyg.2019.01731

Gray level co-occurrence matrix has proven to be a powerful basis for use in texture classification. Various textural parameters calculated from the gray level co-occurrence matrix help understand the details about the overall image content. The aim of this research is to investigate the use of the gray level co-occurrence matrix technique as an absolute image quality metric. The underlying hypothesis is that image quality can be determined by a comparative process in which a sequence of images is compared to each other to determine the point of diminishing returns. An attempt is made to study whether the curve of image textural features versus image memory sizes can be used to decide the optimal image size. The approach used digitized images that were stored at several levels of compression. GLCM proves to be a good discriminator in studying different images however no such claim can be made for image quality. Hence the search for the best image quality metric continues.

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