335 research outputs found

    Finding Ideal Parameters for Recycled Material Fused Particle Fabrication-Based 3D Printing Using an Open Source Software Implementation of Particle Swarm Optimization

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    As additive manufacturing rapidly expands the number of materials including waste plastics and composites, there is an urgent need to reduce the experimental time needed to identify optimized printing parameters for novel materials. Computational intelligence (CI) in general and particle swarm optimization (PSO) algorithms in particular have been shown to accelerate finding optimal printing parameters. Unfortunately, the implementation of CI has been prohibitively complex for noncomputer scientists. To overcome these limitations, this article develops, tests, and validates PSO Experimenter, an easy-to-use open-source platform based around the PSO algorithm and applies it to optimizing recycled materials. Specifically, PSO Experimenter is used to find optimal printing parameters for a relatively unexplored potential distributed recycling and additive manufacturing (DRAM) material that is widely available: low-density polyethylene (LDPE). LDPE has been used to make filament, but in this study for the first time it was used in the open source fused particle fabrication/fused granular fabrication system. PSO Experimenter successfully identified functional printing parameters for this challenging-to-print waste plastic. The results indicate that PSO Experimenter can provide 97% reduction in research time for 3D printing parameter optimization. It is concluded that the PSO Experimenter is a user-friendly and effective free software for finding ideal parameters for the burgeoning challenge of DRAM as well as a wide range of other fields and processes

    Injuries, Ill-Health and Fatalities in White Water Rafting and White Water Paddling

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    White water (WW) activities such as paddling (canoeing and kayaking) and rafting are popular sports for recreational and professional participants. An increase in participation has been seen worldwide. However, these activities come with a risk of injury and even death if not conducted safely. A review was conducted to identify the types of injuries and ill-health that occur as a result of these activities. Injury and fatality rates were assessed to establish the risk attributed to these activities. Web of Science, PubMed, Ergonomics Abstracts and PsycINFO databases were searched and a total of 16 published articles were identified and reviewed. The shoulders and back were the most vulnerable sites for injury in WW paddling. Injuries to the face and lower limbs were most common in WW rafters. However, injury rates are low and estimates are discussed. Due to different methods used across the studies, the reported injury rates are not comparable. This review identified three illnesses incurred through WW activities. There may be more but these are not currently reported in the literature. A relative paucity of studies regarding injuries and fatalities in WW activities was identified. Directions for future research are suggested and discussed

    Sex, Drugs, and Reckless Driving:Are Measures Biased Toward Identifying Risk-Taking in Men?

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    We investigated whether risk-taking measures inadvertently focus on behaviors that are more normative for men, resulting in the overestimation of gender differences. Using a popular measure of risk-taking (Domain-Specific Risk-Taking) in Study 1 (N = 99), we found that conventionally used behaviors were more normative for men, while, overall, newly developed behaviors were not. In Studies 2 (N = 114) and 3 (N = 124), we demonstrate that differences in normativity are reflected in gender differences in self-reported risk-taking, which are dependent on the specific items used. Study 3 further demonstrates that conventional, masculine risk behaviors are perceived as more risky than newly generated, more feminine items, even when risks are matched. We conclude that there is confirmation bias in risk-taking measurement

    Attachment, infidelity, and loneliness in college students involved in a romantic relationship: the role of relationship satisfaction, morbidity and prayer for partner

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    This study examined the mediating effects of relationship satisfaction, prayer for a partner, and morbidity in the relationship between attachment and loneliness, infidelity and loneliness, and psychological morbidity and loneliness, in college students involved in a romantic relationship. Participants were students in an introductory course on family development. This study examined only students (n = 345) who were involved in a romantic relationship. The average age of participants was 19.46 (SD = 1.92) and 25 % were males. Short-form UCLA Loneliness Scale (ULS-8), (Hays and DiMatteo in J Pers Assess 51:69–81, doi:10.1207/s15327752jpa5101_6, 1987); Relationship Satisfaction Scale (Funk and Rogge in J Fam Psychol 21:572–583, doi:10.1037/0893-3200.21.4.572, 2007); Rotterdam Symptom Checklist (De Haes et al. in Measuring the quality of life of cancer patients with the Rotterdam Symptom Checklist (RSCL): a manual, Northern Centre for Healthcare Research, Groningen, 1996); Prayer for Partner Scale, (Fincham et al. in J Pers Soc Psychol 99:649–659, doi:10.1037/a0019628, 2010); Infidelity Scale, (Drigotas et al. in J Pers Soc Psychol 77:509–524, doi:10.1037/0022-3514.77.3.509, 1999); and the Experiences in Close Relationship Scale-short form (Wei et al. in J Couns Psychol 52(4):602–614, doi:10.1037/0022-0167.52.4.602, 2005). Results showed that relationship satisfaction mediated the relationship between avoidance attachment and loneliness and between infidelity and loneliness. Physical morbidity mediated the relationship between anxious attachment and psychological morbidity. Psychological morbidity mediated the relationship between anxious attachment and physical morbidity. The present results expand the literature on attachment by presenting evidence that anxious and avoidant partners experience loneliness differently. Implications for couple’s therapy are addressed. Future research should replicate these results with older samples and married couples.Acknowledgments This research was supported by Grant Number 90FE0022 from the United States Department of Health and Human Services awarded to the last author

    Stigmatization of ‘gay‐sounding’ voices: The role of heterosexual, lesbian, and gay individuals’ essentialist beliefs

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    Voice-based sexual orientation (SO) judgements can prompt group-based discrimination. However, the relationships between stigmatization and essentialist beliefs about vocal cues to SO have not been researched. Two studies examined heterosexuals’ and gay men’s and lesbian women’s essentialist beliefs about voice as a cue of SO to uncover essentialist beliefs’ role in the perpetration and experience of stigma. In Study 1 (N = 363), heterosexual participants believed voice was a better cue to SO for men than for women, and participants’ belief in the discreteness, immutability, and controllability of ‘gay-sounding’ voices was correlated with higher avoidant discrimination towards gay-sounding men. In Study 2 (N = 147), endorsement of essentialist beliefs about voice as a SO cue was associated with self-perceptions of sounding gay amongst gay men and lesbians. Sexual minority participants, especially gay men, who believed that they sounded gay reported more anticipation of rejection and engaged in vigilance in response. Essentialist beliefs about vocal cues to SO are relevant to explaining both the perpetration of stigma by heterosexuals and the experience of stigma for lesbians and gay men

    The Effects of Cognitive Therapy versus ‘No Intervention’ for Major Depressive Disorder

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    BACKGROUND: Major depressive disorder afflicts an estimated 17% of individuals during their lifetimes at tremendous suffering and costs. Cognitive therapy may be an effective treatment option for major depressive disorder, but the effects have only had limited assessment in systematic reviews. METHODS/PRINCIPAL FINDINGS: We used The Cochrane systematic review methodology with meta-analyses and trial sequential analyses of randomized trials comparing the effects of cognitive therapy versus 'no intervention' for major depressive disorder. Participants had to be older than 17 years with a primary diagnosis of major depressive disorder to be eligible. Altogether, we included 12 trials randomizing a total of 669 participants. All 12 trials had high risk of bias. Meta-analysis on the Hamilton Rating Scale for Depression showed that cognitive therapy significantly reduced depressive symptoms (four trials; mean difference -3.05 (95% confidence interval (Cl), -5.23 to -0.87; P<0.006)) compared with 'no intervention'. Trial sequential analysis could not confirm this result. Meta-analysis on the Beck Depression Inventory showed that cognitive therapy significantly reduced depressive symptoms (eight trials; mean difference on -4.86 (95% CI -6.44 to -3.28; P = 0.00001)). Trial sequential analysis on these data confirmed the result. Only a few trials reported on 'no remission', suicide inclination, suicide attempts, suicides, and adverse events without significant differences between the compared intervention groups. DISCUSSION: Cognitive therapy might be an effective treatment for depression measured on Hamilton Rating Scale for Depression and Beck Depression Inventory, but these outcomes may be overestimated due to risks of systematic errors (bias) and random errors (play of chance). Furthermore, the effects of cognitive therapy on no remission, suicidality, adverse events, and quality of life are unclear. There is a need for randomized trials with low risk of bias, low risk of random errors, and longer follow-up assessing both benefits and harms with clinically relevant outcome measures

    Intertwining personal and reward relevance: evidence from the drift-diffusion model.

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    In their seminal paper 'Is our self nothing but reward', Northoff and Hayes (Biol Psychiatry 69(11):1019-1025, Northoff, Hayes, Biological Psychiatry 69(11):1019-1025, 2011) proposed three models of the relationship between self and reward and opened a continuing debate about how these different fields can be linked. To date, none of the proposed models received strong empirical support. The present study tested common and distinct effects of personal relevance and reward values by de-componenting different stages of perceptual decision making using a drift-diffusion approach. We employed a recently developed associative matching paradigm where participants (N = 40) formed mental associations between five geometric shapes and five labels referring personal relevance in the personal task, or five shape-label pairings with different reward values in the reward task and then performed a matching task by indicating whether a displayed shape-label pairing was correct or incorrect. We found that common effects of personal relevance and monetary reward were manifested in the facilitation of behavioural performance for high personal relevance and high reward value as socially important signals. The differential effects between personal and monetary relevance reflected non-decisional time in a perceptual decision process, and task-specific prioritization of stimuli. Our findings support the parallel processing model (Northoff & Hayes, Biol Psychiatry 69(11):1019-1025, Northoff, Hayes, Biological Psychiatry 69(11):1019-1025, 2011) and suggest that self-specific processing occurs in parallel with high reward processing. Limitations and further directions are discussed

    Dimensional and hierarchical models of depression using the Beck Depression Inventory-II in an Arab college student sample

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    Abstract Background An understanding of depressive symptomatology from the perspective of confirmatory factor analysis (CFA) could facilitate valid and interpretable comparisons across cultures. The objectives of the study were: (i) using the responses of a sample of Arab college students to the Beck Depression Inventory (BDI-II) in CFA, to compare the "goodness of fit" indices of the original dimensional three-and two-factor first-order models, and their modifications, with the corresponding hierarchical models (i.e., higher - order and bifactor models); (ii) to assess the psychometric characteristics of the BDI-II, including convergent/discriminant validity with the Hopkins Symptom Checklist (HSCL-25). Method Participants (N = 624) were Kuwaiti national college students, who completed the questionnaires in class. CFA was done by AMOS, version 16. Eleven models were compared using eight "fit" indices. Results In CFA, all the models met most "fit" criteria. While the higher-order model did not provide improved fit over the dimensional first - order factor models, the bifactor model (BFM) had the best fit indices (CMNI/DF = 1.73; GFI = 0.96; RMSEA = 0.034). All regression weights of the dimensional models were significantly different from zero (P Conclusion The broadly adequate fit of the various models indicates that they have some merit and implies that the relationship between the domains of depression probably contains hierarchical and dimensional elements. The bifactor model is emerging as the best way to account for the clinical heterogeneity of depression. The psychometric characteristics of the BDI-II lend support to our CFA results.</p
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