2,037 research outputs found

    Assessing the validity of a learning analytics expectation instrument: A multinational study

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    To assist Higher Education Institutions in meeting the challenge of limited student engagement in the implementation of Learning Analytics services, the Questionnaire for Student Expectations of Learning Analytics (QSELA) was developed. This instrument contains 12 items, which are explained by a purported two-factor structure of Ethical and Privacy Expectations and Service Expectations. As it stands, however, the QSELA has only been validated with students from UK University students, which is problematic on account of the interest in Learning Analytics extending beyond this context. Thus, the aim of the current work was to assess whether the translated QSELA can be validated in three contexts (an Estonian, a Spanish, and a Dutch University). The findings show that the model provided acceptable fits in both the Spanish and Dutch samples, but was not supported in the Estonian student sample. In addition, an assessment of local fit is undertaken for each sample, which provides important points that need to be considered in future work. Finally, a general comparison of expectations across contexts is undertaken, which are discussed in relation to the General Data Protection Regulation (GDPR, 2018)

    Particle-in-cell simulations of rf breakdown

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    Breakdown voltages of a capacitively coupled radio frequency argon discharge at 27 MHz are studied. We use a one-dimensional electrostatic PIC code to investigate the effect of changing the secondary emission properties of the electrodes on the breakdown voltage, particularly at low pd values. Simulation results are compared with the available experimental results and a satisfactory agreement is found.Comment: 12th International Congress on Plasma Physics, 25-29 October 2004, Nice (France

    Kinetic growth walks on complex networks

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    Kinetically grown self-avoiding walks on various types of generalized random networks have been studied. Networks with short- and long-tailed degree distributions P(k)P(k) were considered (kk, degree or connectivity), including scale-free networks with P(k)kγP(k) \sim k^{-\gamma}. The long-range behaviour of self-avoiding walks on random networks is found to be determined by finite-size effects. The mean self-intersection length of non-reversal random walks, , scales as a power of the system size $N$: $ \sim N^{\beta}$, with an exponent $\beta = 0.5$ for short-tailed degree distributions and $\beta < 0.5$ for scale-free networks with $\gamma < 3$. The mean attrition length of kinetic growth walks, , scales as Nα \sim N^{\alpha}, with an exponent α\alpha which depends on the lowest degree in the network. Results of approximate probabilistic calculations are supported by those derived from simulations of various kinds of networks. The efficiency of kinetic growth walks to explore networks is largely reduced by inhomogeneity in the degree distribution, as happens for scale-free networks.Comment: 10 pages, 8 figure

    Critical Exponents, Hyperscaling and Universal Amplitude Ratios for Two- and Three-Dimensional Self-Avoiding Walks

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    We make a high-precision Monte Carlo study of two- and three-dimensional self-avoiding walks (SAWs) of length up to 80000 steps, using the pivot algorithm and the Karp-Luby algorithm. We study the critical exponents ν\nu and 2Δ4γ2\Delta_4 -\gamma as well as several universal amplitude ratios; in particular, we make an extremely sensitive test of the hyperscaling relation dν=2Δ4γd\nu = 2\Delta_4 -\gamma. In two dimensions, we confirm the predicted exponent ν=3/4\nu = 3/4 and the hyperscaling relation; we estimate the universal ratios  / =0.14026±0.00007\ / \ = 0.14026 \pm 0.00007,  / =0.43961±0.00034\ / \ = 0.43961 \pm 0.00034 and Ψ=0.66296±0.00043\Psi^* = 0.66296 \pm 0.00043 (68\% confidence limits). In three dimensions, we estimate ν=0.5877±0.0006\nu = 0.5877 \pm 0.0006 with a correction-to-scaling exponent Δ1=0.56±0.03\Delta_1 = 0.56 \pm 0.03 (subjective 68\% confidence limits). This value for ν\nu agrees excellently with the field-theoretic renormalization-group prediction, but there is some discrepancy for Δ1\Delta_1. Earlier Monte Carlo estimates of ν\nu, which were  ⁣0.592\approx\! 0.592, are now seen to be biased by corrections to scaling. We estimate the universal ratios  / =0.1599±0.0002\ / \ = 0.1599 \pm 0.0002 and Ψ=0.2471±0.0003\Psi^* = 0.2471 \pm 0.0003; since Ψ>0\Psi^* > 0, hyperscaling holds. The approach to Ψ\Psi^* is from above, contrary to the prediction of the two-parameter renormalization-group theory. We critically reexamine this theory, and explain where the error lies.Comment: 87 pages including 12 figures, 1029558 bytes Postscript (NYU-TH-94/09/01

    The presence of disseminated tumour cells in the bone marrow is inversely related to circulating free DNA in plasma in breast cancer dormancy.

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    BACKGROUND: The aim of this study was to gain insight into breast cancer dormancy by examining different measures of minimal residual disease (MRD) over time in relation to known prognostic factors. METHODS: Sixty-four primary breast cancer patients on follow-up (a median of 8.3 years post surgery) who were disease free had sequential bone marrow aspirates and blood samples taken for the measurement of disseminated tumour cells (DTCs), circulating tumour cells (CTCs) by CellSearch and qPCR measurement of overlapping (96-bp and 291-bp) amplicons in circulating free DNA (cfDNA). RESULTS: The presence of CTCs was correlated with the presence of DTCs measured by immunocytochemistry (P=0.01) but both were infrequently detected. Increasing cfDNA concentration correlated with ER, HER2 and triple-negative tumours and high tumour grade, and the 291-bp amplicon was inversely correlated with DTCs measured by CK19 qRT-PCR (P=0.047). CONCLUSION: Our results show that breast cancer patients have evidence of MRD for many years after diagnosis despite there being no overt evidence of disease. The inverse relationship between bone marrow CK19 mRNA and the 291-bp amplicon in cfDNA suggests that an inverse relationship between a measure of cell viability in the bone marrow (DTCs) and cell death in the plasma occurs during the dormancy phase of breast cancer

    Service user experiences of REFOCUS: a process evaluation of a pro-recovery complex intervention

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    Purpose: Policy is increasingly focused on implementing a recovery-orientation within mental health services, yet the subjective experience of individuals receiving a pro-recovery intervention is under-studied. The aim of this study was to explore the service user experience of receiving a complex, pro-recovery intervention (REFOCUS), which aimed to encourage the use of recovery-supporting tools and support recovery-promoting relationships. Methods: Interviews (n=24) and two focus groups (n=13) were conducted as part of a process evaluation and included purposive sample of service users who received the complex, pro-recovery intervention within the REFOCUS randomised controlled trial (ISRCTN02507940). Thematic analysis was used to analyse the data. Results: Participants reported that the intervention supported the development of an open and collaborative relationship with staff, with new conversations around values, strengths and goals. This was experienced as hope-inspiring and empowering. However, others described how the recovery tools were used without context, meaning participants were unclear of their purpose and did not see their benefit. During the interviews, some individuals struggled to report any new tasks or conversations occurring during the intervention. Conclusion: Recovery-supporting tools can support the development of a recovery-promoting relationship, which can contribute to positive outcomes for individuals. The tools should be used, in a collaborative and flexible manner. Information exchanged around values, strengths and goals should be used in care-planning. As some service users struggled to report their experience of the intervention, alternative evaluation approaches need to be considered if the service user experience is to be fully captured

    The association between diet quality and cancer incidence of the head and neck

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    The association between diet quality and head and neck cancer (HNC) was explored using a population-based case–control study of 1170 HNC cases and 1303 age-, race-, and sex-matched controls from the United States. Diet quality was assessed with three diet quality scores (DQS): (a) Healthy Eating Index 2005 (HEI-2005), (b) Mediterranean Diet Score (MDS), and (c) HNC-specific Mediterranean Diet Score (MDS-HNC), a modified MDS that we developed to be more applicable to HNC. Logistic regression models estimated adjusted odds ratios (ORs) and 95% confidence intervals (CIs) representing diet quality–incident HNC associations. We examined effect measure modification (EMM) by body mass index (BMI), race, cigarette smoking, and alcohol consumption and associational heterogeneity by HPV-positivity and tumor site. A one standard deviation summary DQS decrement suggested a consistent inverse association (ORs (CIs)) for the HEI-2005, MDS, and MDS-HNC: 1.35 (1.21, 1.50), 1.13 (1.02, 1.25), and 1.17 (1.06, 1.31), respectively. This association did not vary by tumor site or tumor HPV status, though additive EMM by alcohol use and by BMI was observed. Our findings suggest the Mediterranean diet can be used to study HNC in American populations, and that poor diet quality elevates HNC incidence, particularly among alcohol users

    Post-traumatic stress disorder following childbirth: an update of current issues and recommendations for future research

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    Objective: This paper aimed to report the current status of research in the field of post-traumatic stress disorder following childbirth (PTSD FC), and to update the findings of an earlier 2008 paper. Background: A group of international researchers, clinicians and service users met in 2006 to establish the state of clinical and academic knowledge relating to PTSD FC. A paper identified four key areas of research knowledge at that time. Methods: Fourteen clinicians and researchers met in Oxford, UK to update the previously published paper relating to PTSD FC. The first part of the meeting focused on updating the four key areas identified previously, and the second part on discussing new and emerging areas of research within the field. Results: A number of advances have been made in research within the area of PTSD FC. Prevalence is well established within mothers, several intervention studies have been published, and there is growing interest in new areas: staff and pathways; prevention and early intervention; impact on families and children; special populations; and post-traumatic growth. Conclusion: Despite progress, significant gaps remain within the PTSD FC knowledge base. Further research continues to be needed across all areas identified in 2006, and five areas were identified which can be seen as ‘new and emerging’. All of these new areas require further extensive research. Relatively little is still known about PTSD FC

    Perfectionism and achievement goals in young Finnish ice-hockey players aspiring to make the Under-16 national team

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    Research on perfectionism suggests that is it useful to differentiate between perfectionistic strivings and perfectionistic concerns. Regarding the 2 x 2 achievement goal framework, the usefulness of this differentiation was recently demonstrated in a study with university student athletes (Stoeber, Stoll, Pescheck, & Otto, 2008, Study 2), in which it was found that perfectionistic strivings were associated with mastery-approach and performance-approach goals and perfectionistic concerns with mastery-avoidance, performance-approach, and performance-avoidance goals. Because the study was largely exploratory and only used non-elite athletes, the aim of the present research was to replicate and extend these findings by investigating a sample of 138 young, elite ice-hockey players, while adding further measures of perfectionism and using structural equation modelling (SEM) to confirm the relationships between perfectionistic strivings, perfectionistic concerns,and the 2 x 2 achievement goals. The SEM results showed that, in elite athletes also, perfectionistic strivings are associated with mastery-approach and performance-approach goals, whereas perfectionistic concerns are associated with masteryavoidance, performance-approach, and performance-avoidance goals. Our findings corroborate the importance of differentiating between perfectionistic strivings and perfectionistic concerns when studying perfectionism in sports, because only perfectionistic concerns (and not perfectionistic strivings) are associated with maladaptive patterns of achievement goals

    Do stress and anxiety in early pregnancy affect the progress of labor: Evidence from the Wirral Child Health and Development Study.

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    INTRODUCTION: Despite widespread belief that anxiety causes longer labor, evidence of association is inconsistent. Data gathered as part of a prospective epidemiological longitudinal study were used to investigate associations between antenatal anxiety and pregnancy-specific stress, and labor progression was assessed by duration and use of augmentation. MATERIAL AND METHODS: Pregnant primiparous women completed measures for anxiety and pregnancy-specific stress at 20 weeks' gestation (n = 1145). Birth outcome data were extracted from medical records. Regression analyses and a path analysis assessed associations between antenatal anxiety and pregnancy-specific stress, and indices of labor progression (labor duration and augmentation). RESULTS: Anxiety/pregnancy-specific stress were not directly associated with duration of stage 1 labor (HIGH/LOW anxiety: mean difference = 13.94 minutes, SD = 20.66, 95% CI -26.60 to 54.49, P < .50)/(HIGH/LOW pregnancy-specific stress: mean difference = 12.05 minutes, SD = 16.09, 95% CI -19.52 to 43.63, P < .45). However, anxiety/pregnancy-specific stress were associated with epidural use (HIGH/LOW anxiety: 39% vs 31%, P < .042; HIGH/LOW pregnancy-specific stress: 38% vs 29%, P < .001), which was itself associated with longer labor (mean difference: 158.79 minutes, SD = 16.76, 95% CI 125.89-191.68, P < .001). Anxiety and pregnancy-specific stress were associated with increased likelihood of augmentation but these associations were nonsignificant after accounting for epidural, which was itself highly associated with augmentation. However, path analysis indicated an indirect effect linking pregnancy-specific stress, but not general anxiety, to labor duration and augmentation: elevated pregnancy-specific stress led to greater use of epidural, which was linked to both increased rates of augmentation, and increased labor duration. CONCLUSIONS: Contrary to general belief, general anxiety and specific pregnancy stress were not directly linked to longer duration of stage one labor. However specific pregnancy stress was associated with epidural use, which in turn was significantly associated with risk of augmentation, and longer stage one labor. Identification of pregnancy-specific stress could help to identify women for whom psychological interventions could improve birth experience
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