1,846 research outputs found
Recommended from our members
Longitudinal evidence of the impact of normal thyroid stimulating hormone variations on cognitive functioning in very old age
The purpose of this study was to examine longitudinal associations among thyroid stimulating hormone (TSH) levels and cognitive performance. Data collected at the first three assessment times, approximately 3 years apart, are reported for the survivors (n=45) from a previously published cross-sectional study. Participants were aged 75–93 years at baseline, and data reported were collected in the Kungsholmen Project, a longitudinal project investigating aging and dementia. Analyses revealed that although declining verbal fluency and visuospatial abilities were accompanied by simultaneously declining TSH levels, the pattern of cross-sectional and longitudinal results are interpreted such that declining TSH levels may have caused episodic memory deficits later on. These results were obtained in the examination of 6-year but not 3-year change, and after removal of the cognitive variation associated with depressive mood symptoms
The Chemical Composition of Red Giants, AGB Stars and Planetary Nebulae
The determinations of element abundances in red-giant stars and in particular
in AGB stars are reviewed and the resulting abundances are compared with those
obtained for planetary nebulae in the Galaxy and in nearby galaxies. The
problems, possibilities and implications of such comparisons when estimating
yields from low-mass and intermediate-mass stars are illustrated and commented
on.Comment: 8 pages, 1 figure, to appear in proceedings of IAU Symposium 234,
"Planetary Nebulae in Our Galaxy and Beyond," eds. R. Mendez & M. Barlo
Thresholds for the Dust Driven Mass Loss from C-rich AGB Stars
It is well established that mass loss from AGB stars due to dust driven winds
cannot be arbitrarily low. We model the mass loss from carbon rich AGB stars
using detailed frequency-dependent radiation hydrodynamics including dust
formation. We present a study of the thresholds for the mass loss rate as a
function of stellar parameters based on a subset of a larger grid of such
models and compare these results to previous observational and theoretical
work. Furthermore, we demonstrate the impact of the pulsation mechanism and
dust formation for the creation of a stellar wind and how it affects these
thresholds and briefly discuss the consequences for stellar evolution.Comment: 2 pages, 1 figure. To be published in the proceedings of IAU Symp.
241 on Stellar Populations as Building Blocks of Galaxies, ed. A. Vazdekis et
al. (2007). Replaced to match edited versio
Recommended from our members
Utilization of cognitive support in episodic free recall as a function of apolipoprotein E and vitamin B12 or folate among adults aged 75 years and older
Apolipoprotein E (APOE), vitamin B12, and folate were examined in relation to free recall among 167 community-based older adults. Cognitive support at encoding and retrieval was also taken into account. Participants were classified as APOE e4 or non-e4 allele carriers and as either low or normal vitamin B12 or folate status. A significant association was identified between low vitamin B12 and the e4 genotype in respect to free recall, but only in circumstances of low cognitive support. This result remained after removing dementia cases that occurred up to 6 years after testing. A similar, but nonsignificant, trend was evident in relation to folate. The research is discussed with reference to vulnerability models and genetic influences on brain reserves
Reader’s Workshop: Improving Academic Achievement in Reading
Abstract
The purpose of this study was to determine what affect Reader’s Workshop had on the academic achievement of fifth grade students. Seven students from my fifth grade class had their Reading scores collected and recorded before, and after taught reading skills using Reader’s Workshop. All students in class were taught reading skills through Reader’s Workshop, but only the select few had their scores collected and used for data. Students were taught in small groups where the teacher demonstrated each skill and allowed students to practice the skills in a variety of ways to help keep them engaged. Only students with signed consent participated in the study. Collected test scores and data for each participant were stored in a locked filing cabinet in the principal investigator’s office.
Based on the results that were obtained, it seems as if Reader’s Workshop had a positive affect on the academic achievement of the 5th graders in the study. The majority of the students in the study increased their test scores in both STAR and aReading assessments. The survey also showed an improvement of students’ attitudes towards reading from the middle of the year to the end of the year. It has been a struggle to improve the reading skills of students who are at a variety of different levels as well as help students to like/love to read. Reader’s Workshop has proven to be an effective way to alleviate this issue
The effect of self-evaluation maintenance on friendship choices and cohesion in sport
The purpose of this study was to apply the SEM [Self-Evaluation Maintenance] model to an athletic setting to investigate the role of performance and relevance of task on closeness of friendships and team cohesion.
[This is an excerpt from the abstract. For the complete abstract, please see the document.
Surgery during holiday periods and prognosis in oesophageal cancer: a population-based nationwide Swedish cohort study
OBJECTIVE: Previous studies indicate an increased short-term and long-term mortality from major cancer surgery performed towards the end of the working week or during the weekend. We hypothesised that the prognosis after major cancer surgery is also negatively influenced by surgery conducted during holiday periods. SETTING: Population-based nationwide Swedish cohort study. PARTICIPANTS: Patients undergoing oesophagectomy for oesophageal cancer between 1987 and 2010. Among 1820 included patients, 206 (11.3%) and 373 (20.5%) patients were operated on during narrow and wide holiday periods, respectively. INTERVENTIONS: Narrow (7 weeks) and wide (14 weeks) Swedish holiday periods. PRIMARY AND SECONDARY OUTCOME MEASURES: 90-day all-cause, 5-year all-cause and 5-year disease-specific mortality. RESULTS: Narrow holiday period did not increase all-cause 90-day (HR=0.84, 95% CI 0.53 to 1.33), all-cause 5-year (HR=1.01, 95% CI 0.85 to 1.21) or disease-specific 5-year mortality (HR=1.04, 95% CI 0.87 to 1.26). Similarly, wide holiday period did not increase the risk of 90-day (HR=0.79, 95% CI 0.55 to 1.13), all-cause 5-year (HR=0.96, 95% CI 0.84 to 1.1) or disease-specific 5-year mortality (HR=1.03, 95% CI 0.89 to 1.19). CONCLUSIONS: No measurable effects of holiday periods on short-term or longer term mortality following surgery for oesophageal cancer were observed in this population-based study, indicating that an adequate surgical experience was maintained during holiday periods
Prognostic information from nonmalignant and malignant lymphocytes in follicular lymphoma in relation to therapy
Follicular lymphoma is the most common indolent lymphoma. It is composed of centrocytes and centroblasts, residing in follicles that also harbour nonmalignant immune and
stroma cells. Follicular lymphoma is graded according to the World Health Organization
criteria that are based on the frequency of centroblasts. There is consensus that grades 1 and
2 are indolent, but not whether grade 3 is aggressive. Differences between grades 3A and
3B are also unclear. The nonmalignant cells in the microenvironment interact with the
tumour cells and with each other. These interactions may be important for disease outcome.
Since the introduction of the therapeutic monoclonal anti-CD20 antibody rituximab, the
prognosis of follicular lymphoma has improved. It is likely that the mechanisms of rituximab affect and involve not only CD20+ follicular lymphoma cells but also the surrounding
as well as the systemic immune cells. The aim of this thesis was to identify biological
predictors for outcome in follicular lymphoma in relation to therapy.
In paper I, using flow cytometry, we reported that higher numbers of CD8+ T cells in diagnostic lymph nodes are an independent predictor of better overall and disease-specific
survival. This finding was reproduced in paper II in which computerised quantifications of
tissue microarrays were used for a unifying multivariate model. This model showed that
many cells in the microenvironment were independently important for outcome. Higher
levels of cells positive for CD8 (cytotoxic T cells), forkhead box protein 3 (regulatory T
cells) and programmed death-1 (PD-1+ T cells) correlated with good prognosis, but higher
levels of cells positive for CD4 (helper T cells) and CD68 (macrophages) with poor. The
best predictors for poor outcome were increasing CD4/CD8 and follicular/interfollicular
CD4 ratios, suggesting that outcome is influenced by the balance between detrimental
follicular B-helper and helper2 T-cells on one hand and favourable cytotoxic and helper1 T
cells on the other. In paper III we used prospectively recorded flow cytometry analyses
from two randomised trials where all patients received single rituximab with or without
interferon-α priming. T cells in tumours (both CD4+ and CD8+) were associated with fast
and good clinical responses to rituximab, while T cells in blood (both CD4+ and CD8+)
correlated with slower but good and sustained responses, and were more important for
survival. Interferon-α abrogated the dependence on high numbers of CD8+ cells (in both
blood and tumours) for good rituximab responses. In paper IV we reviewed the follicular
lymphoma grades in 828 patients with long follow-up times, of whom 40% received
upfront rituximab. Compared with grade 1–3A patients and independently of clinical
factors, grade 3B patients showed higher mortality but outcome was improved after upfront
anthracyclines. Grade 3B patients experienced no relapses or deaths beyond five years of
follow-up. Furthermore, patients with grade 3B were different in their clinical characteristics. In the entire population, patients with grade 3A had similar outcome as those with
grade 1–2. However, in patients given upfront rituximab-containing therapy, increasing
grades of 1, 2, and 3A correlated with better overall survival and time to treatment-failure,
independently of clinical factors.
We conclude that outcome in follicular lymphoma is determined by the balance between
competing immune cells in the microenvironment and by their interactions with each other
and with the tumour cells. Rituximab and interferon-α alter the prognostic properties of the
immune cells, and also involve systemic T cells that may be very important for disease
outcome. Grade 3B, or follicular large B-cell lymphoma, is a distinct, aggressive but
curable entity. Grades 1, 2 and 3A are indolent and incurable. Increasing grades predict
better outcome with rituximab therapy. Our findings suggest a future of personalised
therapy based on biological characteristics of the patients and of the tumours
- …