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Grieshaber, Michele Marie. "Interactive calculation of cross-sectional areas for aircraft design and analysis". Thesis, This resource online, 1988. http://scholar.lib.vt.edu/theses/available/etd-04272010-020357/.
Testo completo
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Gardiner, Christopher J. "Large Area Sintering Test Platform Design and Preliminary Study on Cross Sectional Resolution". Scholar Commons, 2017. http://scholarcommons.usf.edu/etd/7026.
Testo completoAbstract (sommario):
Additive manufacturing involves the layer-wise patterned addition of material to create 3D parts, allowing for parts with complex geometries that traditional subtractive manufacturing processes cannot create, while offering good value for low run production parts by eliminating the cost of tooling. Large Area Sintering is a form of powder based additive manufacturing where entire layer cross sections are heated and fused in a single continuous exposure process. This layer by layer powder sintering process is similar to selective laser sintering, but by heating the cross section at a slower and controllable rate there is an opportunity to achieve tighter control over thermal history. This thesis discusses the design, construction, and validation of a large area sintering test platform, as well as a preliminary study on feature resolution. A key component of this system was the integration of an infrared camera, allowing point-wise temperature control of the sintering cross section. There is a hypothesis that longer and controlled heating rates in Large Area Sintering (in comparison to Selective Laser Sintering) would allow the capability to process a wider range of materials, and give more control over the resulting final part properties. The test platform created a repeatable test environment, and successfully demonstrated the capability for point wise temperature control of the sintering cross section, enabling the ability to examine the effects of slower controlled heating rates. Available power on the system was 2.22 W/cm2 for heating, with a temperature control loop time of 160 – 180 ms. The results of the preliminary study on feature resolution also suggested a positive correlation between point wise closed loop temperature control and improved feature resolution, giving motivation for further study.
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Shapla, Tanweer J. "INFERENCE OF ATTRIBUTABLE RISK FOR MULTIPLE EXPOSURE LEVELS UNDER CROSS-SECTIONAL SAMPLING DESIGN". Bowling Green State University / OhioLINK, 2006. http://rave.ohiolink.edu/etdc/view?acc_num=bgsu1148489335.
Testo completo
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Small, Tamara. "Workplace Violence Prevention Training: A Cross-sectional Study of Home Healthcare Workers". University of Cincinnati / OhioLINK, 2020. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1595850151324948.
Testo completo
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Coleman, Emma Elizabeth. "Comparisons of Design Thinking for Engineering Education". Thesis, Virginia Tech, 2018. http://hdl.handle.net/10919/85867.
Testo completoAbstract (sommario):
Design thinking ability is vital for engineers who are tasked with solving society's toughest sustainable development challenges. Prior research identified that the percentage of design thinkers among freshmen engineering students is greater than the percentage among the general population. However, engineering education's lack of attention to fostering creative ability may cause the design thinking ability of senior engineering students to suffer. The research addressed in this thesis compares the design thinking ability of engineering students across age groups, and compares design thinking ability between the design disciplines of engineering and architecture. To draw design thinking comparisons between these groups, a survey with a nine item design thinking instrument was distributed nationally to freshmen engineering students (n= 2,158), senior engineering students (n= 1,893), and senior architecture students (n= 336). The survey instrument was validated by conducting confirmatory factor analysis on the senior engineering and senior architecture samples' data. The Analysis of Variance (ANOVA) test was utilized to statistically compare scores across sample groups. Both the freshmen engineering students (2.80) and senior architecture students (3.30) scored significantly higher on the design thinking scale than senior engineering students (2.59). These results have important implications for engineering educators as engineering education may contribute to a decrease in design thinking among senior engineering students. A lower design thinking score among seniors was consistent across all engineering sub-disciplines and should be of concern to engineering educators, since design thinking skills are critical for the development of engineering solutions to grand societal challenges.Master of Science
Design thinking is a way of thinking about the design process which places the user at the center of the design. Thinking about design in this way is a vital ability for engineers and other design professionals to develop because it enables them to solve “wicked” problems like sustainable development challenges. Wicked problems are those which are difficult to solve due to the number of conflicting components involved. Prior research has found that design thinkers are more prevalent among engineering students in their first year of study than among students in other majors. However, engineering education does not attribute much attention to the development of creative ability which could cause the design thinking ability of engineering students in their final year of study to be worse than the ability of those in their first year, as well as worse than the ability of students who study other design disciplines like architecture. This study compared the design thinking abilities of engineering students in their final year of study to engineering students in their first year and to architecture students in their final year. The goal of making these comparisons was to explore if engineering education helps or hinders the development of design thinking. A survey with nine questions related to design thinking was distributed nationwide. The data from the survey was collected and statistically analyzed. The results showed that the design thinking ability of engineering students in their final year was significantly lower than the ability of first year engineering students and significantly lower than the ability of final year architecture students. A decrease in design thinking ability between freshmen and senior year must be addressed by engineering educators. The National Academy of Engineers and industry leaders are calling for the development of engineers who are design thinkers, and the results of this paper suggest that some changes may need to occur within the engineering education curriculum to accommodate this need.
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Assaf, Musaid Assaf. "Effects of soil cross-sectional modeling on the site design spectra and fundamental period". College Park, Md. : University of Maryland, 2004. http://hdl.handle.net/1903/2023.
Testo completoAbstract (sommario):
Thesis (Ph. D.) -- University of Maryland, College Park, 2004.Thesis research directed by: Civil Engineering. Title from t.p. of PDF. Includes bibliographical references. Published by UMI Dissertation Services, Ann Arbor, Mich. Also available in paper.
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PAGANI, ARIELA FRANCESCA. "NELLA BUONA SORTE: IL PROCESSO DI CAPITALIZZAZIONE NELLA RELAZIONE DI COPPIA". Doctoral thesis, Università Cattolica del Sacro Cuore, 2014. http://hdl.handle.net/10280/2871.
Testo completoAbstract (sommario):
Il presente progetto di ricerca si è focalizzato sul processo di capitalizzazione, ovvero la condivisione di eventi positivi con il/la partner, da cui ci si aspetta una risposta attiva al fine di prolungare ed aumentare i benefici derivanti dall’evento stesso. L’articolazione in tre studi, di carattere quantitativo, ha permesso di approfondire la conoscenza dell’oggetto di ricerca utilizzando diverse metodologie. Il primo studio ha indagato, attraverso un disegno cross-sectional, la struttura della Perceived Responses to Capitalization Attempts scale (PRCA) e, attraverso un disegno longitudinale, i benefici intrapersonali ed interpersonali che derivano dagli stili di risposta di capitalizzazione nel tempo. Il secondo e il terzo studio, attraverso il diary method, hanno approfondito il processo di capitalizzazione attraverso l’introduzione di due aspetti innovativi nel processo: la differenziazione tra eventi positivi interni ed esterni alla relazione e la distinzione tra modalità di comunicazione più o meno esplicita dell’evento positivo. Nello specifico, il secondo studio si è focalizzato sui primi due elementi del processo di capitalizzazione (gli eventi positivi e i tentativi di capitalizzazione), mentre il terzo studio ha riguardato gli ultimi due elementi del processo (le risposte ai tentativi di capitalizzazione e la percezione di responsività da parte del/della partner).The present research project focused on capitalization, that is the process through which people share good news with the partner, who in turn responds in an “active” way to maximize the benefits of the event. Three different studies approached this research object through different methodologies. The aims of the first study were to investigate, through a cross-sectional design, the structure of the Perceived Responses to Capitalization Attempts (PRCA) scale and to examine, through a longitudinal design, the intrapersonal and interpersonal benefits arising from the capitalization responses over time. The second and the third study, through diary methods, attempted to investigate two unexplored aspects of the capitalization process: the differentiation of the type of positive events (internal vs. external to the couple) and the distinction of the type of communication of the event (implicit vs. explicit). Specifically, the second study focused on the first two elements of the capitalization process (positive events and attempts to capitalization), while the third study concerned the last two elements of the process (responses to capitalization attempts and responsiveness).
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PAGANI, ARIELA FRANCESCA. "NELLA BUONA SORTE: IL PROCESSO DI CAPITALIZZAZIONE NELLA RELAZIONE DI COPPIA". Doctoral thesis, Università Cattolica del Sacro Cuore, 2014. http://hdl.handle.net/10280/2871.
Testo completoAbstract (sommario):
Il presente progetto di ricerca si è focalizzato sul processo di capitalizzazione, ovvero la condivisione di eventi positivi con il/la partner, da cui ci si aspetta una risposta attiva al fine di prolungare ed aumentare i benefici derivanti dall’evento stesso. L’articolazione in tre studi, di carattere quantitativo, ha permesso di approfondire la conoscenza dell’oggetto di ricerca utilizzando diverse metodologie. Il primo studio ha indagato, attraverso un disegno cross-sectional, la struttura della Perceived Responses to Capitalization Attempts scale (PRCA) e, attraverso un disegno longitudinale, i benefici intrapersonali ed interpersonali che derivano dagli stili di risposta di capitalizzazione nel tempo. Il secondo e il terzo studio, attraverso il diary method, hanno approfondito il processo di capitalizzazione attraverso l’introduzione di due aspetti innovativi nel processo: la differenziazione tra eventi positivi interni ed esterni alla relazione e la distinzione tra modalità di comunicazione più o meno esplicita dell’evento positivo. Nello specifico, il secondo studio si è focalizzato sui primi due elementi del processo di capitalizzazione (gli eventi positivi e i tentativi di capitalizzazione), mentre il terzo studio ha riguardato gli ultimi due elementi del processo (le risposte ai tentativi di capitalizzazione e la percezione di responsività da parte del/della partner).The present research project focused on capitalization, that is the process through which people share good news with the partner, who in turn responds in an “active” way to maximize the benefits of the event. Three different studies approached this research object through different methodologies. The aims of the first study were to investigate, through a cross-sectional design, the structure of the Perceived Responses to Capitalization Attempts (PRCA) scale and to examine, through a longitudinal design, the intrapersonal and interpersonal benefits arising from the capitalization responses over time. The second and the third study, through diary methods, attempted to investigate two unexplored aspects of the capitalization process: the differentiation of the type of positive events (internal vs. external to the couple) and the distinction of the type of communication of the event (implicit vs. explicit). Specifically, the second study focused on the first two elements of the capitalization process (positive events and attempts to capitalization), while the third study concerned the last two elements of the process (responses to capitalization attempts and responsiveness).
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Umezulike, Bedford Nwabueze. "Is Modernization the Engine of Political Instability?: A Pooled Cross-Sectional Time-Series Test of Causality". Thesis, University of North Texas, 1990. https://digital.library.unt.edu/ark:/67531/metadc331077/.
Testo completoAbstract (sommario):
Traditional studies of the modernization-instability thesis have neglected the simultaneous influence of time and place on the relationship between modernization (social mobilization and political participation) and political instability, and the possible causal linkage between the two concepts. Empirical support for modernization-instability hypothesis will be obtained if and only if there is a strong positive correlation between modernization and political instability and the former causes the latter unidirectionally. Only then can one assert that modernization is exogenous, and that a policy geared toward restricting modernization is a proper anti-instability policy.
This work attempts to address the question of correlation and causality through a pooled time-series cross-sectional data design and the use of Granger-causality tests. Particular attention is paid to the error structure of the models.
Using pooled regression, a model of political instability is estimated for a total of 35 countries for the period 1960-1982. Granger tests are performed on twelve separate countries randomly selected from the 35.
The results indicate that there is the expected positive relationship between modernization and political instability. Further, political institutionalization and economic well-being have strong negative influence on political instability. With regard to causality, the results vary by country. Some countries experience no causality between modernization and political instability, while some witness bidirectional causality. Further, some nations experience unidirectional causality running from modernization to political instability, while some depict a reverse causation.
The main results suggest that modernization and political instability are positively related, and that political instability can have causal influence on modernization, just as modernization can exert causal influence on political instability.
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Stavric, Verna A. "Muscle power after stroke". AUT University, 2007. http://hdl.handle.net/10292/131.
Testo completoAbstract (sommario):
Stroke is the leading cause of disability worldwide. It often leads to mobility limitations resulting from deficits in muscle performance. While reduced muscle strength and rate of force production have been reported, little is known about the power generating capability of people after stroke and its relationship to mobility. Research in other populations has found that measures of muscle power may have a greater association with activity performance than do measures of muscle force alone. Consequently, in an attempt to optimise power, investigators have focused on identifying ideal parameters within which to train for power. One such parameter is the identification of the loading level at which maximal power is generated. Literature reporting optimal loads from both young athletic and healthy older populations has yielded mixed results, making the applicability to a hemiparetic population difficult. The purpose of this study was to investigate muscle power performance at differing loads and to determine at what load muscle power is best elicited in hemiparetic and age and gender matched control groups. A secondary aim was to ascertain whether there is a relationship between the muscle power values obtained and activities such as gait, stair climbing and standing from a chair. Twenty nine hemiparetic volunteers and twenty nine age and gender matched controls were evaluated. Involved and uninvolved legs of the stroke group and a comparison leg of the control group underwent testing. Leg press muscle power was measured using a modified supine leg press machine at 30%, 50% and 70% of a one-repetition maximum (1-RM) load. Participants were positioned on the leg press machine and asked to push, with a single leg, as hard and as fast as they could. Data was collected via a mounted force platform and a linear transducer connected to a platform on which the participants lay. From these, power was able to be calculated. The activities were timed while being performed as fast as possible. The results showed that peak muscle power values differed significantly between the involved, uninvolved and control legs. Peak leg power in all three leg groups was greatest when pushing against a load of 30% of 1-RM. Involved leg peak power tested at 30% of 1-RM (Mean:240; SD:145 W) was significantly lower (p<0.05) than the uninvolved leg (Mean:506; SD:243 W). Both the involved and uninvolved legs generated significantly lower peak power (p<0.05) than the control leg (Mean:757; SD:292 W). Correlations were found between the involved leg peak power and gait speed and involved leg peak power and stair climbing (r=0.6-0.7, p<0.05). No correlation was found between paretic leg peak power and chair stands. The control group leg peak power demonstrated significant associations with the performance of all three activities.In summary, there were significant differences between the involved and the uninvolved leg in power production after stroke. As well, there are significant differences between the uninvolved leg and the leg of those not affected by stroke. Power was related to a number of activities.
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Tengman, Eva. "Long-term consequences of anterior cruciate ligament injury : knee function, physical activity level, physical capacity and movement pattern". Doctoral thesis, Umeå universitet, Sjukgymnastik, 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-86715.
Testo completoAbstract (sommario):
Knee function after more than 20 years post injury is rarely described and none of the few follow-up studies have evaluated functional performance tasks. This thesis investigated self-reported knee function, physical activity level, physical capacity and movement pattern in the long-term perspective (on average 23 years) in persons who had suffered a unilateral ACL injury, treated either with physiotherapy in combination with surgery (ACLR, n=33) or physiotherapy alone (ACLPT, n=37) and compared to age-and-gender matched controls (n=33). This thesis shows that regardless of treatment, there are significant negative long-term consequences on self-reported knee function and physical activity more than 20 years after injury. In comparison to the controls, the ACL-groups (ACLR and ACLPT) had lower knee function as measured by the Lysholm score and the Knee injury and Osteoarthritis Outcome Score (KOOS). The persons with an ACL injury also had a lower knee-specific physical activity level (Tegner activity scale), while no differences were seen in general physical activity level (International Physical Activity Questionnaire, IPAQ) compared to healthy controls. Regarding physical capacity, both ACL groups showed inferior jump capacity in the injured leg compared to the non-injured leg. However, compared to controls the ACL-injured had a relatively good jump performance. Knee extension peak torque, concentric and eccentric, was also lower for the injured leg compared to the non-injured leg for both ACLR and ACLPT. In addition, the ACLPT group showed reduced eccentric knee flexion torque of the injured leg. The non-injured leg, on the other hand, showed almost equal jump capacity and strength as controls. Balance in single-limb stance (30s) was inferior in persons who had an ACL injury. This was true for both the injured and non-injured leg and regardless of treatment. Movement pattern during the one-leg hop was analysed by a set of kinematic variables consisting of knee angles (flexion, abduction, rotation) and Centre of Mass (CoM) placement in relation to the knee and ankle joints. Both ACLR and ACLPT displayed movement pattern asymmetries between injured and non-injured legs. In comparison to controls, the ACLR group had a similar movement pattern with the exception of larger external knee rotation at Initial contact and less maximum internal rotation during the Landing. ACLPT showed several differences compared to controls both regarding knee angles and CoM placement. The ACL-injured persons with no-or-low knee osteoarthritis (OA) had better knee function as reflected by higher scores on Lysholm and KOOS subscale ‘symptom’ compared to those with moderate-to-high OA. The degree of OA had no influence on reported physical activity level, jump capacity, peak torque or the kinematic variables. In conclusion, this thesis indicates that persons with a unilateral ACL injury, regardless of treatment, have some negative long-term consequences e.g. self-reported knee function, knee-specific activity level, strength and balance deficits, when compared to age-and-gender matched controls. The results, however, also indicate that the ACL-injured can manage reasonably well in some jumps and general activity level but have an inferior performance in more knee-demanding tasks. The ACLR group had similar movement pattern with the exception of knee rotation, indicating that a reconstruction may restore the knee biomechanics to some extent. The ACLPT group on the other hand, seem to use compensatory movement strategies showing several differences compared to controls.
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Hawkes, Teresa, e Teresa Hawkes. "Effect of the Long-Term Health Practices of Tai Chi, Meditation and Aerobics on Adult Human Executive Attention: A Cross-Sectional Study". Thesis, University of Oregon, 2012. http://hdl.handle.net/1794/12340.
Testo completoAbstract (sommario):
Meditation, Tai Chi, and moderate aerobic exercise have been shown to positively affect executive attention. We compared the executive attention efficiency and aerobic capacity of long-term Tai Chi, meditation plus exercise, aerobic fitness, and sedentary participants. We hypothesized that because meditation and Tai Chi include moderate aerobic exertion and executive attention training, these groups would show significantly greater executive attention efficiency compared to aerobic exercisers or sedentary control groups. Our results support this. Tai Chi and meditation but not aerobic fitness practitioners significantly outperformed sedentary controls on key executive measures: percent switch costs and P3b ERP switch amplitude (Tai Chi, p = .001; p = .031, respectively; meditation, p = .006; p = .003, respectively). This suggests participation in chronic health practices requiring moderate aerobic exertion and attentional focus may offset declines in aerobic, neuromotor, and executive attention capacity often seen in normal aging.
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Beltramo, Michele. "National level sprinter’s competitive anxiety and performance success according to ability level and sex: an observational study with a cross-sectional design". Thesis, Mittuniversitetet, Institutionen för hälsovetenskap, 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:miun:diva-39441.
Testo completo
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MAFFONI, MARINA. "Wellness and distress in healthcare professionals dealing with end-of-life and bioethical issues (WeDistress HELL): An observational, multicentre, cross-sectional research project with a multimethod design". Doctoral thesis, Università degli studi di Pavia, 2021. http://hdl.handle.net/11571/1422615.
Testo completoAbstract (sommario):
Introduction:
Medical practice implies an increasing amount of bioethical issues that may negatively impact on health care professionals wellbeing. However, to date, little is known about the experience of burnout and (moral) distress related with end of life and bioethical issues in everyday working life.
Objectives:
to study variables (meaning in life, stress, moral distress, ethical climate, resilience, positive and negative affects) that may impact on health care professionals dealing with end-of-life and bioethics issues.
Materials and methods:
The study will be conducted using a multi-method design, using both quantitative and qualitative approaches.
The anonymous questionnaire administered one time only to each participant was composed by socio-demographic questions, Maslach Burnout Inventory – General Survey, Schedule for Meaning in Life Evaluation, Maugeri Stress Index, Moral Distress Scale-Revised, Hospital Ethical Climate Survey, Connor-Davidson Resilience Scale, Positive Affect and Negative Affect Scale. Semi-structured interviews have been conducted, too.
Main results:
Managerial support and ethical vision of patient care were negatively related to emotional exhaustion, directly and through moral distress. Professionals high in resilience and positive affectivity benefited more from the protective effect of managerial support on emotional exhaustion through moral distress. Moreover, resilience improves healthcare professionals’ wellbeing and professional self-efficacy, directly and indirectly, as mediated by the ethical vision of patient care. Highly resilient professionals benefit more from the positive effect of ethical vision of patient care on wellbeing in presence of high managerial support.
The qualitative part shed light on both stressors (e.g. emotion management regarding death, communication of poor diagnosis/prognosis) and protective factors (e.g. social support, positive approach and value of past experience) experienced by palliative care professionals and medical student. Moreover, palliative care professionals considered the Italian law on Advance Directives as a useful instrument for self-determination and protection despite the presence of some critical aspects.
Discussion:
This study may help to focus on risk and protective factors to be monitored during the health care provider’s career. It may also provide information useful for preventing and supportive interventions in medical practice with end-of-life and life-threatening patients.
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Hartman, Deborah Smith. "Self-Efficacy and Cultural Competency Assessment of the Associate Degree Nursing Student". ScholarWorks, 2017. https://scholarworks.waldenu.edu/dissertations/3995.
Testo completoAbstract (sommario):
Effective nursing care can be threatened when nurses are not culturally attuned with their patients. Associate degree nursing (ADN) students receive information about diverse ethnicities in the nursing curriculum, but it may not be sufficient to provide the expertise necessary to care for patients of various cultural backgrounds. The purpose of this quantitative study was to explore the 2nd year ADN students' levels of cultural competence and their perceptions of self-efficacy in working with Caucasian, African American, Native American, Hispanic, and Asian ethnicities. The study used a cross-sectional survey design to determine if a relationship existed between the students' reported cultural competencies and their self-efficacy scores while providing care to patients of these diverse cultures. The process of cultural competence in the delivery of health care services was used as the theoretical framework for this study. A volunteer convenience sample of 64 2nd-year ADN students completed the Nurse Cultural Competence Scale and the Cultural Self-Efficacy Scale. The Pearson-Product Moment correlation revealed a significant negative, moderate relationship between self-efficacy and the students' perceptions of cultural competence. A project was designed to enhance skills and knowledge to improve the students' cultural competency while caring for patients of Asian, Native American, and Hispanic cultures because minimal familiarity of those cultures contributed most to the negative correlation. Research on methods to improve cultural competence among health care professionals should be continued. Positive social change will occur as nursing students gain proficiency in their abilities to provide culturally appropriate care to patients of diverse ethnic backgrounds.
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Chen, Hongyun. "Comparison of Safety Performance by Design Types at Freeway Diverge Areas and Exit Ramp Sections". Scholar Commons, 2010. http://scholarcommons.usf.edu/etd/3470.
Testo completoAbstract (sommario):
The primary objective of the study is to evaluate the safety performance of different freeway exit types used in current practical designs. More specific, the research objectives include the following two parts: 1) to compare the safety performance of different design types at freeway diverge areas and exit ramp sections; and 2) to identify the impact factors contributing to the crashes happening at these two specific segments.
The study area includes four subjects, the freeway widely-spaced diverge areas; the freeway closely-spaced diverge areas; the left-side off-ramps and the exit ramp sections. For the freeway diverge areas, design types were defined based on the number of lanes used by vehicular traffic to exit freeways and lane-balance theory. Four exit ramp types were considered for the widely-spaced diverge area, including single-lane exit ramps (Type 1), sing-lane exit ramps without a taper (Type 2), two-lane exit ramps with an optional lane (Type 3), and two-lane exit ramps without an optional lane (Type 4).
For the closely-spaced diverge areas, three types, named as Type A, Type B and Type C, are selected to compare the safety performances among the three types. For the left-side off-ramp at the freeway diverge area, this study examined the two most widely used design types at the left-side freeway diverge areas in Florida, which are defined as Type I (one-lane left-side off-ramp), and Type II (two-lane left-side off-ramp). Type I is comparable to Type 1 design type and Type II is comparable to Type 3 design type at widely-spaced freeway diverge area. For the exit ramp sections, four ramp configurations, including diamond, out connection, free-flow loop and parclo loop, were considered.
Cross-sectional comparisons were conducted to compare the crash frequency, the crash rate, the crash severity and target crash types between different design groups. Crash predictive models were also built to quantify the impacts of various contributing factors. The results of this study would expectedly help transportation decision makers develop tailored technical guidelines governing the selection of the optimum design combinations at freeway diverge areas and exit ramp sections.
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Domrow, Nathan Craig. "Design, maintenance and methodology for analysing longitudinal social surveys, including applications". Thesis, Queensland University of Technology, 2007. https://eprints.qut.edu.au/16518/1/Nathan_Domrow_Thesis.pdf.
Testo completoAbstract (sommario):
This thesis describes the design, maintenance and statistical analysis involved in undertaking a Longitudinal Survey.
A longitudinal survey (or study) obtains observations or responses from individuals over several times over a defined period. This enables the direct study of changes in an individual's response over time. In particular, it distinguishes an individual's change over time from the baseline differences among individuals within the initial panel (or cohort). This is not possible in a cross-sectional study. As such, longitudinal surveys give correlated responses within individuals. Longitudinal studies therefore require different considerations for sample design and selection and analysis from standard cross-sectional studies.
This thesis looks at the methodology for analysing social surveys. Most social surveys comprise of variables described as categorical variables.
This thesis outlines the process of sample design and selection, interviewing and analysis for a longitudinal study. Emphasis is given to categorical response data typical of a survey.
Included in this thesis are examples relating to the Goodna Longitudinal Survey and the Longitudinal Survey of Immigrants to Australia (LSIA). Analysis in this thesis also utilises data collected from these surveys. The Goodna Longitudinal Survey was conducted by the Queensland Office of Economic and Statistical Research (a portfolio office within Queensland Treasury) and began in 2002. It ran for two years whereby two waves of responses were collected.
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Domrow, Nathan Craig. "Design, maintenance and methodology for analysing longitudinal social surveys, including applications". Queensland University of Technology, 2007. http://eprints.qut.edu.au/16518/.
Testo completoAbstract (sommario):
This thesis describes the design, maintenance and statistical analysis involved in undertaking a Longitudinal Survey. A longitudinal survey (or study) obtains observations or responses from individuals over several times over a defined period. This enables the direct study of changes in an individual's response over time. In particular, it distinguishes an individual's change over time from the baseline differences among individuals within the initial panel (or cohort). This is not possible in a cross-sectional study. As such, longitudinal surveys give correlated responses within individuals. Longitudinal studies therefore require different considerations for sample design and selection and analysis from standard cross-sectional studies. This thesis looks at the methodology for analysing social surveys. Most social surveys comprise of variables described as categorical variables. This thesis outlines the process of sample design and selection, interviewing and analysis for a longitudinal study. Emphasis is given to categorical response data typical of a survey. Included in this thesis are examples relating to the Goodna Longitudinal Survey and the Longitudinal Survey of Immigrants to Australia (LSIA). Analysis in this thesis also utilises data collected from these surveys. The Goodna Longitudinal Survey was conducted by the Queensland Office of Economic and Statistical Research (a portfolio office within Queensland Treasury) and began in 2002. It ran for two years whereby two waves of responses were collected.
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Fernandes, Bertrand. "Nondestructive Evaluation of Deteriorated Prestressing Strands Using Magnetic Field Induction". University of Toledo / OhioLINK, 2010. http://rave.ohiolink.edu/etdc/view?acc_num=toledo1271432554.
Testo completo
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Nilsson, Felix, e Minelius David Lindsten. "Love to Help: The Roles of Compassion and Empathy in Regards to Altruism". Thesis, Örebro universitet, Institutionen för juridik, psykologi och socialt arbete, 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:oru:diva-83885.
Testo completoAbstract (sommario):
Unresolved global problems, such as extreme poverty, ask for a better understanding of what predicts altruism and what does not. The aim of this thesis project was to address this topical and timely research question by studying the predictive role of compassion and empathy in understanding altruism. In past research on the relationship between altruism and empathy, distinct empathic processes (Perspective taking, Empathic concern, Personal distress, Emotional contagion, and Behavioral contagion) have been often lumped together and the context dependency of the relationship has been insufficiently taken into account, resulting in confusion and contradictory findings. Compassion overcomes these issues. The present web-based survey with previous or current university students (age 18-45; N=240) aimed to clarify relationships between components of empathy, compassion, and altruism. It was hypothesized that (1) compassion would predict altruism beyond all components of empathy; (2) Empathic concern would mediate the relationship between Perspective taking and altruism; (3) compassion would mediate the relationship between Empathic concern and altruism, and (4) higher levels of compassion would result in a reduced negative relationship between Personal distress and altruism. The results supported all hypotheses except for the final one. These findings are discussed in context of previous research and theory, considering the current study limitations and with focus on theoretical and practical implications. In sum, the findings suggest that efforts to motivate altruism should focus on invoking positive emotions of warmth, concern, and relatability. Care should be taken to avoid unnecessary Personal distress when invoking altruism, as this reduces its likelihood.
21
Chakravarty, Uttam Kumar. "Section builder: a finite element tool for analysis and design of composite". Diss., Atlanta, Ga. : Georgia Institute of Technology, 2008. http://hdl.handle.net/1853/22640.
Testo completoAbstract (sommario):
Thesis (Ph. D.)--Aerospace Engineering, Georgia Institute of Technology, 2008.Committee Chair: Bauchau, Olivier; Committee Member: Craig, James; Committee Member: Hodges, Dewey; Committee Member: Mahfuz, Hassan; Committee Member: Volovoi, Vitali.
22
Dionne, Marie-Pierre. "Does Work Experience Using Technology for College and University Nursing Students Influence the Nursing Informatics Competency Scores by the End of the 4th Year Program for One School in the Province of Ontario, Canada? A Cross-Sectional Design". Thesis, Université d'Ottawa / University of Ottawa, 2014. http://hdl.handle.net/10393/31352.
Testo completoAbstract (sommario):
The use of Information Technology (IT) in healthcare organizations is omnipresent. The nursing curriculum needs to include IT in order to prepare nursing students to acquire Nursing Informatics (NI) competencies before entering the workplace. The literature review suggests that pre-licensure nurses are ill prepared to enter the workforce because they lack some of the essential computer skills that employers are seeking when hiring new graduates (Fetter, 2009a; Gassert, 2008; Ornes & Gassert, 2007). The lack of defined competencies in NI is a worldwide problem (Chang, 2007; Fetter, 2009b; Staggers, Gassert, & Curran, 2001; Ragneskog & Gerdner, 2006). This thesis will examine two questions: 1) Do nursing students increase their NI competency scores progressively in their school program from year 1 to 4? 2) Do nursing students with work experience requiring the use of technology outside of the curriculum get higher scores for NI competencies than those without by the end of 4th year? A questionnaire was given to 176 nursing students asking them to rate their computer use and computer knowledge. The results were consistent for both independent variables of year of study and experience with technology in the work setting. There is no interaction present between variables; they each influence individually the total score for NI competencies for nursing students. The results show NI competencies progressively increasing over the four academic years. The nursing students scored higher still when they had technology experience in any work field on NI competencies. The combination of academic and work experience that uses IT provides nursing students with more opportunities to practice and assimilate their NI competencies before graduation.
23
Erdogdu, Emel [Verfasser], Canan [Akademischer Betreuer] [Gutachter] Basar-Eroglu e Tamer [Gutachter] Demiralp. "Using Multimodal MRI Techniques to Derive a Biomarker for Tracking the Pathological Changes Occurring at Different Stages of Cognitive Decline in Parkinson's Disease in a Cross-Sectional Study Design / Emel Erdogdu ; Gutachter: Canan Basar-Eroglu, Tamer Demiralp ; Betreuer: Canan Basar-Eroglu". Bremen : Staats- und Universitätsbibliothek Bremen, 2017. http://d-nb.info/1144439450/34.
Testo completo
24
Le, Fleur Celeste Catherine. "Comparing the BDI II and the HADS (HADS-D) as a screening tool for depression amongst HIV infected individuals attending a public health clinic". Thesis, University of the Western Cape, 2011. http://etd.uwc.ac.za/index.php?module=etd&action=viewtitle&id=gen8Srv25Nme4_2733_1363786537.
Testo completoAbstract (sommario):
This study utilised secondary data from a larger study that looked at individuals that are already infected by HIV which is entitled Implicative personal dilemmas and cognitive conflicts in health decision making in HIV positive adults and adults with AIDS. The primary aim of the larger study was to examine the cognitive construction of the individual and how they utilised their individual resources to construct who they are and how they perceived the difficulties and challenges that they face and the decisions they make regarding their health. HIV and AIDS is a debilitating disease and it affects millions worldwide. South Africa, presently, has the largest burden of this disease with those between the ages of 15 &ndash
49 years of age being most affected. As previously
mentioned the decisions that individuals make can impact on their health. Decisions to take necessary precautions such as protected sex during sexual intercourse can decrease the
progression of the disease. Decisions made regarding abstinence of risky behaviour as well as being committed to taking medication could also positively impact health. People living with HIV and AIDS find it
difficult to adjust to the challenges that this disease presents. Depression is often experienced due to the changes in self image and perception. Studies show that
females are twice more likely to experience depression than men. There has however been no conclusive evidence showing the reason for this, however, the perception of stress based on
gender could shed some light on this matter and how these perceptions can increase the likelihood of women being more vulnerable to depression. Due to the limitation of this study, it will
only look at depression as it relates to HIV and AIDS. Psychological problems such as depression can hamper the adjustment process and the effect of depression is evident in that it can lower the CD 4 + cells. Not only are those
living with HIV and AIDS affected by depression, but they also have a lifetime prevalence to depression. It is important to have an effective screening tool for depression so that the detection of this
disease can be made and effective treatment can be implemented to enhance health. The sample consisted of 113 adult participants that have already been diagnosed with HIV and AIDS. The
primary aim of this study was to compare the Beck&rsquo
s Depression Inventory II (BDI II) and the Hospital Anxiety and Depression Scale &ndash
(the Depression component) (HADS-D) as a screening tool
for depression. Exploratory Factor Analysis revealed a 5 factor structure which accounted for 60.14 % of the total variance. The HADS yielded one factor accounting for 14.33% of total variance. The BDI II has proven to be more a reliable measure of depression with 0.89 according to the Cronbach&rsquo
s Alpha co efficient opposed to 0.375 as per the HADS-D. The secondary aim was to establish
the sociodemographic and disease profiles of the participants under study.
25
Shim, Minsuk. "Models comparing estimates of school effectiveness based on cross-sectional and longitudinal designs". Thesis, University of British Columbia, 1991. http://hdl.handle.net/2429/31519.
Testo completoAbstract (sommario):
The primary purpose of this study is to compare the six models (cross-sectional, two-wave, and multiwave, with and without controls) and determine which of the models most appropriately estimates school effects. For a fair and adequate evaluation of school effects, this study considers the following requirements of an appropriate analytical model.
First, a model should have controls for students' background characteristics. Without controlling for the initial differences of students, one may not analyze the between-school differences appropriately, as students are not randomly assigned to schools.
Second, a model should explicitly address individual change and growth rather than status, because students' learning and growth is the primary goal of schooling. In other words, studies should be longitudinal rather than cross-sectional. Most researches, however, have employed cross-sectional models because empirical methods of measuring change have been considered inappropriate and invalid. This study argues that the discussions about measuring change have been unjustifiably restricted to the two-wave model. It supports the idea of a more recent longitudinal approach to the measurement of change. That is, one can estimate the individual growth more accurately using multiwave data.
Third, a model should accommodate the hierarchical characteristics of school data because schooling is a multilevel process. This study employs an Hierarchical Linear Model (HLM) as a basic methodological tool to analyze the data.
The subjects of the study were 648 elementary students in 26 schools. The scores on three subtests of Canadian Tests of Basic Skills (CTBS) were collected for this grade cohort across three years (grades 5, 6 and 7). The between-school differences were analyzed using the six models previously mentioned. Students' general cognitive ability (CCAT) and gender were employed as the controls for background characteristics.
Schools differed significantly in their average levels of academic achievement at grade 7 across the three subtests of CTBS. Schools also differed significantly in their average rates of growth in mathematics and reading between grades 5 and 7. One interesting finding was that the bias of the unadjusted model against adjusted model for the multiwave design was not as large as that for the cross-sectional design. Because the multiwave model deals with student growth explicitly and growth can be reliably estimated for some subject areas, even without controls for student intake, this study concluded that the multiwave models are a better design to estimate school effects. This study also discusses some practical implications and makes suggestions for further studies of school effects.Education, Faculty of
Educational and Counselling Psychology, and Special Education (ECPS), Department of
Graduate
26
Wilson, Susan E. "Comparing Self-Perceptions of Skills and Knowledge among College Students: Cross-Sectional Versus Panel Designs". W&M ScholarWorks, 1995. https://scholarworks.wm.edu/etd/1539626018.
Testo completo
27
Cheng, Li-Wei, e 鄭力維. "Cross-Sectional Topology Design of a Long Feed-System Cage". Thesis, 2013. http://ndltd.ncl.edu.tw/handle/54811598477663040263.
Testo completoAbstract (sommario):
碩士大葉大學
機械與自動化工程學系
102
The main purpose of engineering optimization is to improve the original design with the constraint of limited resource. Topology optimization method, taking one step further than the sizing and shape optimization, can result in a true optimum design of a structure. This thesis applies topology optimization method in the cross-section design of a cage of a long-travel drive system. Different material usage percentages are used to investigate the optimum material distribution of the cross section design. Results show that the optimum design can be obtained while a proper percentage of material is assigned.
28
Mitchell, Melissa A. "A comparison of the diagonal and cross-sectional design when assessing longitudinal mediation". 2009. http://etd.nd.edu/ETD-db/theses/available/etd-10292009-094253/.
Testo completo
29
Huang, Jun-jia, e 黃俊嘉. "The Optimum Design for the Cross-Sectional Form of Retaining Grooves of Screw Tail Point Dies". Thesis, 2011. http://ndltd.ncl.edu.tw/handle/46014113537495413284.
Testo completoAbstract (sommario):
碩士國立高雄應用科技大學
模具工程系
99
The study aims to explore how the retaining grooves of screw tail point dies influence the mold-filling by means of the forging analysis software DEFORM-3D and the Taguchi experimental method. In this study, a 3D manufacture process is simulated, and all the major control factors are analyzed and planned through the Taguchi experimental method. The results reflect the variations of each individual control factor at different standards, from which we can derive the influence of these factors on how retaining grooves increase the completeness of mold-filling and a combination of major factors at specific standards which can result in an optimum design. The Taguchi method is utilized to analyze how retaining grooves and their cross-sectional forms affect the shaping of the finished items in the forging process. The discoveries are as follows: (1) The parameters of retaining grooves have substantial influence on the finished items in respect of (a) the packing volume, (b) the maximum principal stress, and (c) the effective stress; (2) In terms of the influence on the packing volume and the stresses, the top four parameters are: (a) the distance from the retaining groove to the cavity edge (b) the cross-sectional form of the retaining grooves, (c) the depth of the retaining groove, and (d) the side angle of the die. The outcomes drawn from the simulation indicate that adding the design of the retaining grooves have significant effects on (1) increasing the volume of the finished items, (2) reducing the maximum principal stress and the effective stress, and (3) decreasing the surface area of flashes. Based on the analytical results, the design leads to the following improvements: (1) decrease the surface area of the flashes by 40.89%; (2) enhance the effects of blank-filling remarkably; (3) reduce the maximum principal stress by 10.27% and the effective stress by 0.87% (of the finished items) as well as the effective stress by 24.6% (of the die). As for the optimum design, the most desirable performance comes with the retaining groove whose cross-sectional form is semicircle with the depth of 0.25mm. It is also suggested that the filling effect is related to the distance from the retaining groove to the cavity edge. These findings can be applied as a reference in respect of designing the retaining grooves of the dies, hence the increase of the yield rate.
30
Cheng, Ching-Chuang, e 鄭景全. "Functional Outcome and Gait analysis after Anterolateral Thigh Flap Reconstruction Surgery: Follow-up and Cross-sectional Design". Thesis, 2006. http://ndltd.ncl.edu.tw/handle/00630365514490840434.
Testo completoAbstract (sommario):
碩士國立成功大學
物理治療研究所
94
Abstract Background and Purpose. The anterolateral thigh (ALT) flap had been developed for widespread clinical applications. The vastus lateralis muscle could be sacrificed during the dissection process of ALT flap, however it was the largest compartment of the quadriceps femoris muscle and might play an important role on the stability of the knee joint in daily living. To date only few studies have provided objective assessments for the postoperative donor-side complications of ALT flap reconstructive surgery, in which weakness of knee extensors was the main focus reported. There may be more sequels requiring further attention. The purpose of this study was to set up systemic assessments for evaluating the sequels for ALT flap reconstructive surgery, including the Knee injury and Osteoarthritis Outcome Score (KOOS), thigh circumferences, lower extremity flexibility, related muscle strength, endurance of the knee extensors, weight bearing pattern and gait analysis (walking speed, peak loading rate at heel strike transients, muscle activation pattern before heel strike). Methods. Two study designs (follow-up and cross-sectional design) were conducted in this study. In the follow-up design, 8 patients having ALT flap reconstructive surgery were recruited to participate evaluation before and at 3 months and 6 months after surgery. In the cross-sectional design, 11 ALT flap patients were recruited to participate postoperative evaluation only for both the donor legs and the healthy legs at more than six months after surgery. Due to the high drop-out rate at 6 month after surgery, several Wilcoxon’s signed-rank tests were conducted simply to examine the differences between pre-operative assessments and the assessments 3 month after surgery. In the cross-sectional design, the Wilcoxon’s signed-rank tests were used to examine differences in the assessments between donor legs and healthy legs. Results. Subscales of the KOOS (function in daily living, function in sport and recreation and knee related quality of life), thigh circumference at 15 cm above patella, the rectus femoris flexibility, all related muscle strength (knee extensors, hip flexors, hip abductors, knee flexors, and hip extensors), knee extensor endurance, and weight bearing percentage were significantly lower at 3 months after surgery in the donor legs compared to pre-operative status (p<0.05). There was still a decrease in function in sport and recreation and knee related quality of life, the rectus femoris flexibility, related muscle strength (knee extensors, hip flexors, hip abductors), and weight bearing percentage in the donor legs even at 6 month after surgery. In addition, significantly earlier activation of the rectus femoris before heel strike in the donor legs were found at 3 month after surgery (p<0.05). Further, the results of our cross-sectional study also showed that the donor legs exhibited significantly weaker knee extensors, hip flexors, and hip abductors, limited rectus femoris flexibility, and decreased weight bearing percentage than the healthy legs even at the time later than 6 months after surgery (p<0.05). At this time, activation of the vastus medialis in the swing phase of gait cycle before heel strike also showed significantly earlier onset in the donor legs than in the healthy legs (p<0.05). Conclusions. In present study we have demonstrated significantly decreased knee function (especially in subscales of function for sports and recreation, and knee related quality of life), significant weakness in hip flexors, hip abductors, and knee extensors, significantly limited rectus femoris flexibility, and significantly reduced weight bearing percentage in the donor legs during squatting in patients after ALT flap reconstructive surgery. We also found unchanged walking speed and peak loading rate at heelstrike transients accompanying with apparent gait alterations such as significantly earlier activation of rectus femoris and vastus medialis in the swing phase of gait cycle. Obviously a compensatory mechanism for the control strategies of gait pattern has been developed after ALT flap reconstructive surgery, and might have contributed to the reduction of impact at heelstrike transients. The findings of the present study have provided thorough understanding to the sequels of ALT flap and might help to suggest more efficient rehabilitation interventions after ALT flap reconstructive surgery. In addition, circumferential evidence has been proposed in the present study to show the possibility of reduced risk for gonarthrisis after ALT flap reconstructive surgery by altering gait control strategies in daily walking pattern.
31
Wei, Te-Jung, e 魏德榮. "Investigation of the Variation of Damping in Shock Absorber Through the Design of Cross-Sectional Geometry of Piston". Thesis, 2018. http://ndltd.ncl.edu.tw/handle/87pjua.
Testo completoAbstract (sommario):
碩士國立虎尾科技大學
機械與電腦輔助工程系碩士班在職專班
106
In the vehicle shock absorber，The performance of the Damper performance is sufficient to affect the overall operation of the shock absorber，However, the most basic factor affecting the Damper of the shock absorber is the efficacy of the piston，The efficacy of the piston is Good or bad distinguished by the amount of damping force generated by the fluid passing through the cross-sectional geometry of the piston，However, The performance of the piston section geometry is sufficient to affect a Damper can even determine the performance orientation of a group of shock absorbers，it is impossible to have a reliable piston reference direction and data as the design basis when developing the damper。 This paper proposes a reference data for the geometric relative damping performance of a piston section，the piston model is made experimentally，the piston is actually assembled to the damper cylinder and the data is measured on the universal testing machine and the damping force data is obtained，The experimental results verify that the results of the numerical method and its set condition variables can be consistent with the performance of the actual shock absorber components。 The results obtained in this study show that the numerical method results are very close to the experimental results，the error value of the numerical method and the experimental method obtained in the combination of 27 sets of variable combinations at three factors and three bench marks of variables is 6.8% on average，the maximum damping force in the width 6mm Chamfer 0.4mm Length 13mm combination produces a maximum damping force of 153kg in the geometry of the piston，it can be seen from the present study that the importance of the Piston section geometry variable of the piston section to the damping force is from big to small respectively than the the width is greater than the chamfer greater than the length。
32
De, Pau Antonina. "Nurses' perceptions of leadership, teamwork, and safety climate in a community hospital in western Canada: A cross-sectional survey design". 2014. http://hdl.handle.net/1993/23878.
Testo completoAbstract (sommario):
ABSTRACT
Patient safety and safety outcomes in hospitals are a major concern. A hospital’s safety climate indicates the degree to which the organization prioritizes patient safety and achieves intended care outcomes. Relationships between nurse managers and frontline nurses and relationships between health care team members are pivotal in promoting a positive safety climate which in turn reduces adverse patient outcomes. Therefore, the purpose of this study was to examine frontline nurses’ perceived relationships with nurse managers and health team members to identify factors associated with safety climate (SC) in a community hospital located in a western Canadian city.
The study was guided by Leader-Member Exchange (LMX) theory. Leader-Member Exchange theory postulates that dyadic relationships and work roles develop over time through a series of exchanges between nurse managers and frontline nurses. The study further incorporated Team-member exchange (TMX), a theoretical extension of LMX. Team-Member Exchange was used to guide the study of reciprocal exchanges among nurses and other members of the health care team.
A non-experimental, cross-sectional survey design was used to explore the relationship between acute care nurses’ perceived LMX, TMX, and SC. A convenience sampling technique was employed. Licensed practical nurses (LPNs) and registered nurses (RNs) were invited to complete a survey package comprised of four scales. A response rate of 31.1% was achieved with N=105. The majority of respondents were female (89.5%), over 45 years of age, and employed part-time. About half of the respondents were diploma-prepared nurses, whereas the other half had a baccalaureate degree in nursing.
Based upon data’s non-normal distribution and various levels of variables, Kruskall Wallis H statistics were used to assess and compare groups in terms of the nurses’ education, gender, length of experience in their current position, specialty experience, organization experience, age, and LMX, TMX, and SC scores. Age was the sole demographic factor that had a statistically significant positive association with LMX and SC. This finding supported the notion that mature nurses enhance the SC.
The relationship between TMX, LMX, and SC was explored through Spearman’s rho correlation statistics. LMX and TMX were found to have statistically significant relationships with SC. Multivariable regression analysis was used to identify factors with an association with SC. Nurses’ relationships with team members had a slightly stronger association with SC in comparison with LMX. Over 66% of SC variance was accountable by LMX, TMX, and nurses’ age.
This study’s results support the nurse manager who partners with nurses to promote team work to deliver safe patient care and accomplish organizational goals. The presence of strong leadership that incorporates LMX and TMX theories into practice with the reliance upon mature nurses may facilitate the attainment of a positive SC and positive patient outcomes. Further longitudinal studies are recommended to add to the knowledge of the relationships between LMX, TMX, SC and patient outcomes.
33
Amaral, Luísa Maria de Jesus. "The ulnar variance phenomenon in Portuguese female and male gymnasts. A multi-thematic approach studied by a cross-sectional and longitudinal design". Doctoral thesis, 2012. https://repositorio-aberto.up.pt/handle/10216/65281.
Testo completo
34
Amaral, Luísa Maria de Jesus. "The ulnar variance phenomenon in Portuguese female and male gymnasts. A multi-thematic approach studied by a cross-sectional and longitudinal design". Tese, 2012. https://repositorio-aberto.up.pt/handle/10216/65281.
Testo completo
35
Martins, Alberto Miguel Bizarro. "Análise e Optimização de Pontes Atirantadas de Betão". Doctoral thesis, 2015. http://hdl.handle.net/10316/29215.
Testo completoAbstract (sommario):
Tese de doutoramento em Engenharia Civil, no ramo de Estruturas, apresentada ao Departamento de Engenharia Civil da Faculdade de Ciências e Tecnologia da Universidade de CoimbraAs pontes de tirantes são estruturas altamente hiperstáticas nas quais o tabuleiro se comporta como uma viga apoiada elasticamente nos tirantes inclinados. Estas pontes representam soluções estruturalmente eficientes para médios e longos vãos. A sua construção tem-se estendido a todo o mundo com diversas soluções estruturais, desde pequenas pontes pedonais até pontes rodoviárias e ferroviárias de médio e grande vão. O seu comportamento é governado pela rigidez dos elementos estruturais (tabuleiro, torres e tirantes) e pela distribuição de forças de pré-esforço nos tirantes. A sua popularidade deve-se não só à sua eficiência estrutural e construtiva mas também a vantagens económicas e estéticas, devido ao seu aspecto elegante e transparente. O projecto de estruturas é um processo iterativo em que se procura, através da alteração de determinados parâmetros do sistema estrutural, uma solução que satisfaça um conjunto de critérios relacionados com a segurança, utilização e economia. No caso das pontes de tirantes o projecto envolve aspectos de grande complexidade relacionados com uma variedade de problemas como: a definição do sistema estrutural, a determinação das dimensões das secções transversais dos elementos, o cálculo das forças de pré-esforço a aplicar nos tirantes, a consideração das fases construtivas e de efeitos geometricamente não-lineares. Para as pontes em betão assume ainda especial relevância a consideração dos efeitos diferidos. A optimização estrutural não é habitualmente utilizada na prática da Engenharia Civil. No entanto, no projecto de estruturas de grandes dimensões como as pontes de tirantes, o uso de técnicas de optimização surge naturalmente, como uma forma eficiente de tratar a enorme quantidade de informação envolvida, tendo em vista a redução de custos dos materiais e a obtenção de soluções económicas e estruturalmente eficientes. Deste modo, realizou-se um estudo acerca da análise estrutural e optimização de pontes atirantadas com tabuleiros em betão, de modo a desenvolver uma ferramenta de apoio ao projecto deste tipo de estruturas. Para tal, desenvolveu-se um programa computacional, que inclui um módulo de análise estrutural e outro módulo destinado à análise de sensibilidades e optimização. O primeiro módulo baseia-se no método dos elementos finitos e tem em conta todos os efeitos e acções relevantes, nomeadamente, as fases construtivas, os efeitos diferidos e os efeitos geometricamente não-lineares. No segundo módulo a resposta da estrutura face a variações nas variáveis de decisão é obtida através de uma análise de sensibilidades pelo método analítico discreto directo. O projecto de pontes atirantadas de betão é formulado como um problema de optimização multi-objectivo, considerando objectivos de custo mínimo, deslocamentos e tensões, obtendo-se soluções de Pareto. O Princípio da Máxima Entropia é utilizado para obter a solução minimax através da minimização de uma função escalar convexa. A minimização do custo é formulada como a minimização do volume de material. Consideraram-se como variáveis de decisão as forças de pré-esforço e secções dos tirantes, as forças de pré-esforço no tabuleiro e as dimensões das secções transversais dos elementos do tabuleiro e das torres. As características e capacidades do modelo numérico desenvolvido são ilustradas através da resolução de um conjunto de exemplos de aplicação relativos a problemas de optimização de uma ponte atirantada de betão de dimensões reais.
Cable-stayed bridges are highly redundant structures in which the deck behaves like a continuous beam elastically supported by the inclined stays. These bridges represent structural efficient solutions for medium-to-long spans and are widely used all over the world, ranging from small pedestrian bridges to large span railway and road bridges. Their behaviour is governed by the stiffness of the load bearing elements (deck, towers and cable stays) and the cable force distribution. Their popularity is owed not only to its structural and construction efficiency but also to economic and aesthetic advantages, due to their elegant and transparent appearance. Structural design is an iterative process which, through changes in some parameters of the structural system, seeks a solution that satisfies a set of criteria related to safety, serviceability and economy. Cable-stayed bridge design deals with some complex problems, such as: the definition of the structural system, the finding of the members’ cross-sections, the calculation of the cable forces’ distribution, the construction stages and geometrical non-linear effects. For concrete bridges the time-dependent effects are of major importance and must be considered. Structural optimization is not commonly used in civil engineering practice. However, in the design of large structures like cable-stayed bridges, the use of optimization techniques naturally arises as an efficient way to deal with the large amount of information aiming at reducing the material costs and thus obtaining economical and structurally efficient solutions. Therefore, in order to develop a tool to aid in the design of concrete cable-stayed bridges a study concerning the structural analysis and optimization of such structures was carried out. For that, a computer program was developed, including two modules: a structural analysis module and sensitivity analysis and optimization module. The first module is based in the finite element method and takes into account all the actions and relevant effects, namely, the construction stages, the time-dependent effects and the geometrical nonlinear effects. In the second module the structural response to changes in the design variables is done by a discrete direct sensitivity analysis procedure. The design of concrete cable-stayed bridges is formulated as a multi-objective optimization problem with objectives of minimum cost, minimum deflections and stresses and a Pareto solution is sought. An entropy-based approach is used to find the minimax solution through the minimization of a convex scalar function. The cost minimization is formulated as the minimization of material volume. The design variables considered are the cable-stays areas and prestressing forces, the deck prestressing forces and the deck and towers cross-sections. The features and applicability of the proposed method are demonstrated by numerical examples concerning optimization problems of a real sized concrete cable-stayed bridge.
36
Fleur, Celeste Catherine Le. "Comparing the BDI II and the hads (HADS-D) as a screening tool for depression amongst HIV infected individuals attending a public health clinic". Thesis, 2010. http://hdl.handle.net/11394/3444.
Testo completoAbstract (sommario):
This study utilised secondary data from a larger study that looked at individuals that are already infected by HIV which is entitled Implicative personal dilemmas and cognitive conflicts in health decision making in HIV positive adults and adults with AIDS. The primary aim of the larger study was to examine the cognitive construction of the individual and how they utilised their individual resources to construct who they are and how they perceived the difficulties and challenges that they face and the decisions they make regarding their health. HIV and AIDS is a debilitating disease and it affects millions worldwide. South Africa, presently, has the largest burden of this disease with those between the ages of 15 – 49 years of age being most affected. As previously mentioned the decisions that individuals make can impact on their health. Decisions to take necessary precautions such as protected sex during sexual intercourse can decrease the progression of the
disease. Decisions made regarding abstinence of risky behaviour as well as being committed to taking medication could also positively impact health. People living with HIV and AIDS find it difficult to adjust to the challenges that this disease presents. Depression is often experienced due to the changes in self image and perception. Studies show that females are twice more likely to experience depression than men. There has however been no conclusive evidence showing the
reason for this, however, the perception of stress based on gender could shed some light on this matter and how these perceptions can increase the likelihood of women being more vulnerable to depression. Due to the limitation of this study, it will only look at depression as it relates to HIV and AIDS. Psychological problems such as depression can hamper the adjustment process and the effect of depression is evident in that it can lower the CD 4 + cells. Not only are those living with HIV and AIDS affected by depression, but they also have a lifetime prevalence to depression. It is important to have an effective screening tool for depression so that the detection of this disease can be made and effective treatment can be implemented to enhance health. The sample consisted of 113 adult participants that have already been diagnosed with HIV and AIDS. The primary aim of this study was to compare the Beck’s Depression Inventory II (BDI II) and the Hospital Anxiety and Depression Scale –(the Depression component) (HADS-D) as a screening tool for depression.Exploratory Factor Analysis revealed a 5 factor structure which accounted for 60.14 % of the total variance. The HADS yielded one factor accounting for 14.33% of total variance. The BDI II has proven to be more a reliable measure of depression with 0.89 according to the Cronbach’s Alpha co
efficient opposed to 0.375 as per the HADS-D. The secondary aim was to establish the sociodemographic and disease profiles of the participants under study.Magister Psychologiae - MPsych
37
Zivor, Jacqueline Carol Ann. "Self-esteem of aids orphans: a descriptive study". Diss., 2007. http://hdl.handle.net/10500/2034.
Testo completoAbstract (sommario):
In the light of the child's self-esteem that is affected by traumatic events, the goal of the research was to explore and describe the self-esteem of children orphaned by HIV/AIDS. The researcher made use of a quantitative research method. 30 (N=30) respondents, both male (n=16) and female (n=14), between the ages of 11 to 15, were randomly sampled for inclusion in the study. Each participant completed a self-report measure of self-esteem, The Culture-free Self-esteem Inventory for Children, which yielded a score of Global Self-esteem, as well as in four sub-domains including: General, Social, Academic and Parent-related Self-esteem.
The results of this study demonstrated that the participants experienced a lowered self-esteem. These findings were explored in light of a literature review, after which conclusions and recommendations were provided.Social Work
M. Diac. (Play Therapy)
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Horne, Maria, G. McCracken, A. Walls, P. J. Tyrrell e C. J. Smith. "Organisation, practice and experiences of mouth hygiene in stroke unit care: a mixed methods study". 2015. http://hdl.handle.net/10454/7373.
Testo completoAbstract (sommario):
noAims and objectives To (1) investigate the organisation, provision and practice of oral care in typical UK stroke units; (2) explore stroke survivors', carers' and healthcare professionals' experiences and perceptions about the barriers and facilitators to receiving and undertaking oral care in stroke units. Background Cerebrovascular disease and oral health are major global health concerns. Little is known about the provision, challenges and practice of oral care in the stroke unit setting, and there are currently no evidence-based practice guidelines. Design Cross-sectional survey of 11 stroke units across Greater Manchester and descriptive qualitative study using focus groups and semi-structured interviews. Methods A self-report questionnaire was used to survey 11 stroke units in Greater Manchester. Data were then collected through two focus groups (n = 10) with healthcare professionals and five semi-structured interviews with stroke survivors and carers. Focus group and interview data were recorded, transcribed verbatim and analysed using framework approach. Results Eleven stroke units in Greater Manchester responded to the survey. Stroke survivors and carers identified a lack of oral care practice and enablement by healthcare professionals. Healthcare professionals identified a lack of formal training to conduct oral care for stroke patients, inconsistency in the delivery of oral care and no set protocols or use of formal oral assessment tools. Conclusion Oral care post-stroke could be improved by increasing healthcare professionals' awareness, understanding and knowledge of the potential health benefits of oral care post-stroke. Further research is required to develop and evaluate the provision of oral care in stroke care to inform evidence-based education and practice.
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(8300103), Shams R. Rahmani. "Digital Soil Mapping of the Purdue Agronomy Center for Research and Education". Thesis, 2020.
Cerca il testo completoAbstract (sommario):
This research work concentrate on developing digital soil maps to support field based plant phenotyping research. We have developed soil organic matter content (OM), cation exchange capacity (CEC), natural soil drainage class, and tile drainage line maps using topographic indices and aerial imagery. Various prediction models (universal kriging, cubist, random forest, C5.0, artificial neural network, and multinomial logistic regression) were used to estimate the soil properties of interest.