Matching Items (24)

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3D Printed Gas Dynamic Virtual Nozzles for X-Ray Laser Sample Deliveryand Optical Characterization of Microjets and Microdroplets

Description

Gas Dynamic Virtual Nozzles (GDVN) produce microscopic flow-focused liquid jets and are widely used for sample delivery in serial femtosecond crystallography (SFX) and time-resolved solution scattering. Recently, 2-photon polymerization (2PP)

Gas Dynamic Virtual Nozzles (GDVN) produce microscopic flow-focused liquid jets and are widely used for sample delivery in serial femtosecond crystallography (SFX) and time-resolved solution scattering. Recently, 2-photon polymerization (2PP) made it possible to produce 3D-printed GDVNs with submicron printing resolution. Comparing with hand- fabricated nozzles, reproducibility, and less developing effort, and similarity of the performance of different 3D printed nozzles are among the advantages of using 3D printing techniques to develop GDVN’s. Submicron printing resolution also makes it possible to easily improve GDVN performance by optimizing the design of nozzles. In this study, 3D printed nozzles were developed to achieve low liquid and gas flow rates and high liquid jet velocities. A double-pulsed nanosecond laser imaging system was used to perform Particle Tracking Velocimetry (PTV) in order to determine jet velocities and assess jet stability/reproducibility. The testing results of pure water jets focused with He sheath gas showed that some designs can easily achieve stable liquid jets with velocities of more than 80 m/s, with pure water flowing at 3 microliters/min, and helium sheath gas flowing at less than 5 mg/min respectively. A numerical simulation pipeline was also used to characterize the performance of different 3D printed GDVNs. The results highlight the potential of making reproducible GDVNs with minimum fabrication effort, that can meet the requirements of present and future SFX and time-resolved solution scattering research.

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Agent

Created

Date Created
  • 2020

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Intergenerational variation in cultural models of body size in Puerto Rico

Description

Culture informs ideas about healthy and acceptable body types. Through globalization the U.S.-European body model has become increasingly significant in local contexts, influencing local body models. While Puerto Ricans have

Culture informs ideas about healthy and acceptable body types. Through globalization the U.S.-European body model has become increasingly significant in local contexts, influencing local body models. While Puerto Ricans have historically valued plump bodies - a biocultural legacy of a historically food scarce environment - this dissertation investigated shifts in these ideals across generations to a stronger preference for thinness. A sample of 23 intergenerational family triads of women, and one close male relative or friend per woman, were administered quantitative questionnaires. Ethnographic interviews were conducted with a sub-sample of women from 16 triads and 1 quintet. Questions about weight history and body sizes were used to address cultural changes in body models. Findings indicate the general trend for all generations has been a reduction in the spectrum of acceptable bodies to an almost singular idealized thin body. Female weight gain during puberty and influence of media produced varied responses across age groups. Overall, Puerto Ricans find it acceptable to gain weight with ageing, during a divorce, and postpartum. Thin bodies are associated with beauty and health, but healthy women that do not resemble the thin ideal, submit themselves to dangerous weight loss practices to achieve self and social acceptance. Further research and direct interventions need to be conducted to alter perceptions that conflate beauty with health in order to address the `normative discontent' women of all ages experience. Weight discrimination and concern with being overweight were evident in Puerto Rican everyday life, indicated by the role of media and acculturation in this study. Anti-fat attitudes were stronger for individuals that identified closely with United States culture. Exposure to drama and personal transformation television programs are associated with increased body image dissatisfaction, and increased exposure to variety shows and celebrity news shows is associated with increased anti-fat attitudes and body dissatisfaction. In sum, the positive valuation of fat in the Puerto Rican cultural body size model in the 1970s has shifted toward a negative valuation of fat and a preference for thin body size.

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Agent

Created

Date Created
  • 2013

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The relations of household chaos to children's language development: the mediating roles of children's effortful control and parenting

Description

This study drew upon a bioecological framework to empirically investigate the relations between environmental chaos and preschoolers' language across time, including the potentially mediating roles of children's effortful control and

This study drew upon a bioecological framework to empirically investigate the relations between environmental chaos and preschoolers' language across time, including the potentially mediating roles of children's effortful control and parenting. Child sex also was examined as a moderator of these relations. For this study, the following data were collected at 30, 42, and 54 months of age. Household chaos and (at 30 months) socioeconomic status (SES) were reported by mothers. Children's effortful control (EC) was rated by mothers and nonparental caregivers, and was observed during a number of laboratory tasks. Maternal vocalizations were assessed during free play sessions with their children (at 30 and 42 months), and supportive and unsupportive parenting behaviors and affect were observed during free play and teaching tasks at each age. Mothers also reported on their own reactions to children's negative emotions. Finally, (at 54 months) children's expressive and receptive language was measured with a standard assessment. Structural equation modeling and path analyses indicated that SES at 30 months and greater levels of household chaos at 42 months predicted not only poorer language skills, but also deficits in children's EC and less supportive parenting in low-income mothers at 54 months, even when controlling for stability in these constructs. Children's effortful control at 42 months, but not parenting, positively predicted later language, suggesting that EC may play a mediating role in the relations between household chaos, as well as SES, and preschoolers' language abilities. Child sex did not moderate the pattern of relations. Post-hoc analyses also indicated that the negative relation between chaos and language was significant only for children who had low EC at 42 months. This study represents a much-needed addition to the currently limited longitudinal research examining environmental chaos and children's developmental outcomes. Importantly, findings from this study elucidate an important process underlying the links between chaos and children's language development, which can inform interventions and policies designed to support families and children living in chaotic home environments.

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Agent

Created

Date Created
  • 2012

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Marital disruption and chronic disease in older adults

Description

The beginning of the large Baby Boomer cohort's retirement, coupled with the increased divorce rate among older adults, means that there will be more single older adults than ever before

The beginning of the large Baby Boomer cohort's retirement, coupled with the increased divorce rate among older adults, means that there will be more single older adults than ever before beginning to consider living arrangements and long-term care needs as they age. Using a cumulative (dis)advantage framework and logistic regression, this research examines whether marital disruption and social support at Wave 1 increase the odds of having a specific chronic disease at Wave 2, diabetes, heart failure, and hypertension. The sample consists of 2,261 adults age 57-85 who participated in the first two waves of the National Social Life, Health, and Aging Project (NSHAP). Being female and having more positive social support reduced the odds of having diabetes at Wave 2. Being older at Wave 1 increased the odds of having congestive heart failure at Wave 2. Being black and having a happy family life in childhood increased the odds of having hypertension at Wave 2. Suggestions for increasing positive social support are discussed, along with implications for long-term care and health education.

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Agent

Created

Date Created
  • 2016

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Young children's digital game culture in everyday life: an ethnographic case study

Description

This dissertation examines how young children engage with digital games at home and how parents think and talk about their children's digital gaming. This is an ethnographic case study of

This dissertation examines how young children engage with digital games at home and how parents think and talk about their children's digital gaming. This is an ethnographic case study of the digital game playing of six three-year-old children in six families. This study combines ethnographic methods and critical perspectives to construct analyses that have the potential to rethink young children's digital game play. The focus of this study is on understanding how digital gaming functions in children's everyday lives. This study shows that young children's digital game play takes place in the interstices of their everyday family life. Digital games do not entirely change or displace other practices in early childhood, but they are integrated into existing young children's everyday practices in their family life. Digital games as a source of young children's imagination enrich young children's play rather than substitute for young children's spontaneous non-digital play. Young children and their parents tactically use young children's mobile game play to cope with their modern life. Negotiating over game selections, time, and space between young children and their parents is an everyday practice of families and digital games are a site not only for family power struggles but also of shared activity. Digital games reflect the dominant culture in which they are produced. However, this study shows that young children do not passively receive the messages in the games but rather make sense of the game contents according to their everyday local experiences. Digital games are now a part of everyday practices for both adults and young children, and young children's digital game play reflects contemporary society.

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Agent

Created

Date Created
  • 2015

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Communicating religious disaffiliation: a study of the context, family conversations, and face negotiation among young adults

Description

This study investigated how young adults communicate their decision to religiously disaffiliate to their parents. Both the context in which the religious disaffiliation conversation took place and the communicative behaviors

This study investigated how young adults communicate their decision to religiously disaffiliate to their parents. Both the context in which the religious disaffiliation conversation took place and the communicative behaviors used during the religious disaffiliation conversation were studied. Research questions and hypotheses were guided by Family Communication Patterns Theory and Face Negotiation Theory. A partially mixed sequential quantitative dominate status design was employed to answer the research questions and hypotheses. Interviews were conducted with 10 young adults who had either disaffiliated from the Church of Jesus Christ of Latter-day Saints or the Watch Tower Society. During the interviews, the survey instrument was refined; ultimately, it was completed by 298 religiously disaffiliated young adults. For the religious disaffiliation conversation’s context, results indicate that disaffiliated Jehovah’s Witnesses had higher conformity orientations than disaffiliated Latter-day Saints. Additionally, disaffiliated Jehovah’s Witnesses experienced more stress than disaffiliated Latter-day Saints. Planning the conversation in advance did lead to the disaffiliation conversation being less stressful for young adults. Furthermore, the analysis found that having three to five conversations reduced stress significantly more than having one or two conversations. For the communicative behaviors during the religious disaffiliation conversation, few differences were found in regard to prevalence of the facework behaviors between the two groups. Of the 14 facework behaviors, four were used more often by disaffiliated JW than disaffiliated LDS—abuse, passive aggressive, pretend, and defend self. In terms of effectiveness, the top five facework behaviors were talk about the problem, consider the other, have a private discussion, remain calm, and defend self. Overall, this study begins the conversation on how religious disaffiliation occurs between young adults and their parents and extends Family Communication Patterns Theory and Face Negotiation Theory to a new context.

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Agent

Created

Date Created
  • 2015

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An exploration of environmental influences on elementary school attainment in rural Guatemala

Description

Increasing elementary school attainment globally remains a key focus for improving internationally child development (UNESCO, 2010), and for girls in particular (UNICEF, 2015). This dissertation was designed to test and

Increasing elementary school attainment globally remains a key focus for improving internationally child development (UNESCO, 2010), and for girls in particular (UNICEF, 2015). This dissertation was designed to test and explore specific areas to target to improve educational attainment for rural indigenous communities using a mixed-methods approach (i.e., quantitative survey of 264 mothers and qualitative interviews with 37 of those mothers 3.5 years later) with a Mayan community in Camanchaj, Guatemala. The first study was designed to examine the educational trajectories available to children in this community (e.g., dropping out, graduating 6th grade) by age, grade, and gender, and identified risks and vulnerabilities for educational attainment. The second study was a logistic regression to examine maternal factors that predict the likelihood of a child graduating from elementary school or dropping out in this community, above and beyond covariates of poverty and health and found that maternal education predicted educational attainment for both boys as girls as well as maternal beliefs about the importance of school for getting a job, which was particularly strong predictor for boys. The third study probed findings from Studies 1 and 2 using Experiential Thematic Analyses and Frequency Analyses to examine processes and cognitions involved in a child’s graduating elementary school, dropping out, and community beliefs and attitudes regarding education and gender equality. Findings highlight the need for interventions that are contextually and culturally appropriate and that consider complex and interacting factors of poverty, health, and gender inequality as well as maternal and community-level attitudes and beliefs to promote elementary school attainment globally.

Contributors

Agent

Created

Date Created
  • 2016

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Understanding romantically intimate relational escalation and de-escalation among high functioning individuals possessing an autism spectrum disorder

Description

Romantic relationships are an important aspect of anyone's life. For individuals with an autism spectrum disorder, this is true as well. However, these people may experience relational dynamics and trajectories

Romantic relationships are an important aspect of anyone's life. For individuals with an autism spectrum disorder, this is true as well. However, these people may experience relational dynamics and trajectories that are in some aspects either similar to or markedly different from those who are not on the spectrum. There are very few studies analyzing and understanding how adults with an ASD navigate romantic relationships. This particular study examined how turning points pertaining to relational escalation or de-escalation were recognized and understood by eight individuals (four men and four women) possessing an ASD. The Retrospective Interview Technique (RIT) was implemented in order to accrue data from participants. Each participant completed a RIT graph mapping out a romantic relationship of their choice by understanding when a turning point was identified and placing a mark next to the corresponding level of relational closeness or attachment. Once all turning points were mapped out, they were connected with lines so that a visual representation of the entire relationship may be viewed. Participants were then queried about how they knew that particular event (or mark) to be a turning point, how it impacted the relationship, and how they were, personally, influenced by it (how they responded to the event). Interviews were transcribed and explored through a grounded theory approach. Specifically, Braun and Clarke's thematic analysis method was applied to articulate interview data. The research revealed four main themes (Relational Genesis, Relational Escalation, Relational De-escalation and Conflict Management) as well as seventeen sub themes. Limitations for this study, information relating to discourses surrounding autism spectrum disorders and romantically intimate relationships, as well as, areas for future study are also discussed.

Contributors

Agent

Created

Date Created
  • 2016

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Children's perceptions of teachers' responses to bullying: relational schemas as predictors of seeking teachers' assistance

Description

The purpose of this study was to investigate the role teacher-relational bullying schemas may have in influencing the likelihood of youth seeking teachers' assistance. The first goal of the study

The purpose of this study was to investigate the role teacher-relational bullying schemas may have in influencing the likelihood of youth seeking teachers' assistance. The first goal of the study was to assess whether supportive and helpful teacher-responses to bullying schemas (TRBS) were associated with greater likelihood of involving teachers, and unhelpful TRBSs was related to lower likelihood of teacher seeking coping. The second goal was to examine possible differences in TRBS and likelihood of seeking help based on sex, grade, personal behavioral blame, personal aggression, and victimization. Towards these aims, data were gathered from 320 fourth and sixth grade students (152 boys; 168 girls) in the fall and spring of the academic year. MANOVA analyses revealed sex and grade differences, such as sixth grade boys were least likely to tell their teacher and most likely to blame their own behavior for being bullied than any other group. Results from a series of regression analyses found personal behavior blame and peer-directed aggression was related with less likelihood of telling. In addition, the association between parents or principal TRBS and telling the teacher was moderated by personal behavioral blame. Moreover, punishment predicted lower probability of telling concurrently and longitudinally.

Contributors

Agent

Created

Date Created
  • 2013

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Sibling behaviors and Mexican-origin adolescents' after-school activities

Description

Time adolescents spend in organized or informal skill based activities after school is associated with a variety of positive developmental outcomes. Little is known about how siblings might shape adolescents'

Time adolescents spend in organized or informal skill based activities after school is associated with a variety of positive developmental outcomes. Little is known about how siblings might shape adolescents' motivation to participate in after-school activities. The current study applied the expectancy value model and ecological theory to understand if sibling behaviors were related to adolescents' after-school activities for 34 Mexican origin families. Qualitative and quantitative results suggested siblings engaged in five promoting behaviors (i.e., support, provider of information, role modeling, comparison, co-participation) and three inhibiting behaviors (i.e., babysitting, transportation, and negativity) towards adolescent activity participation. Furthermore, sibling behaviors differed by adolescent characteristics (i.e., cultural orientation, familism, and neighborhood) and sibling characteristics (i.e., gender, age). The results provide evidence of the various promoting and inhibiting socialization behaviors sibling might use to influence adolescents' activity motivation.

Contributors

Agent

Created

Date Created
  • 2012