5,741 research outputs found
Experiences of Looping for Students with Learning Disabilities: A Phenomenological Case Study
The problem is the academic, social, and emotional needs of students with learning disabilities are not being met within the general classroom. Looping, the practice of a teacher staying with the same group of students for two or more years, has been suggested as an educational approach designed to meet the needs of students with disabilities. The purpose of this research project was to examine the experiences of looping for students with learning disabilities from the perspectives of the looping teacher, the students with learning disabilities, and their parents. Therefore, a phenomenological case study design was utilized. The methods of data collection included teacher and student interviews, a parental questionnaire, examination of student artifacts, and observations of everyday school activities. Examination of the research data revealed no significant improvement in the academic or speech performances of the students with learning disabilities; yet, their social skills and emotional competencies improved
Control of steroid receptor dynamics and function by genomic actions of the cochaperones p23 and Bag-1L
Molecular chaperones encompass a group of unrelated proteins that facilitate the correct assembly and disassembly of other macromolecular structures, which they themselves do not remain a part of. They associate with a large and diverse set of coregulators termed cochaperones that regulate their function and specificity. Amongst others, chaperones and cochaperones regulate the activity of several signaling molecules including steroid receptors, which upon ligand binding interact with discrete nucleotide sequences within the nucleus to control the expression of diverse physiological and developmental genes. Molecular chaperones and cochaperones are typically known to provide the correct conformation for ligand binding by the steroid receptors. While this contribution is widely accepted, recent studies have reported that they further modulate steroid receptor action outside ligand binding. They are thought to contribute to receptor turnover, transport of the receptor to different subcellular localizations, recycling of the receptor on chromatin and even stabilization of the DNA-binding properties of the receptor. In addition to these combined effects with molecular chaperones, cochaperones are reported to have additional functions that are independent of molecular chaperones. Some of these functions also impact on steroid receptor action. Two well-studied examples are the cochaperones p23 and Bag-1L, which have been identified as modulators of steroid receptor activity in nuclei. Understanding details of their regulatory action will provide new therapeutic opportunities of controlling steroid receptor action independent of the widespread effects of molecular chaperones
Deriving a Provisional Tolerable Intake for Intravenous Exposure to Silver Nanoparticles Released from Medical Devices
Silver nanoparticles (AgNP) are incorporated into medical devices for their anti-microbial characteristics. The potential exposure and toxicity of AgNPs is unknown due to varying physicochemical particle properties and lack of toxicological data. The aim of this safety assessment is to derive a provisional tolerable intake (pTI) value for AgNPs released from blood-contacting medical devices. A literature review of in vivo studies investigating critical health effects induced from intravenous (i. v.) exposure to AgNPs was evaluated by the Annapolis Accords principles and Toxicological Data Reliability Assessment Tool (ToxRTool). The point of departure (POD) was based on an i. v. 28-day repeated AgNP (20 nm) dose toxicity study reporting an increase in relative spleen weight in rats with a 5% lower confidence bound of the benchmark dose (BMDL05) of 0.14 mg/kg bw/day. The POD was extrapolated to humans by a modifying factor of 1,000 to account for intraspecies variability, interspecies differences and lack of long-term toxicity data. The pTI for long-term i. v. exposure to 20 nm AgNPs released from blood-contacting medical devices was 0.14 μg/kg bw/day. This pTI may not be appropriate for nanoparticles of other physicochemical properties or routes of administration. The methodology is appropriate for deriving pTIs for nanoparticles in general
Demyelination and axonal preservation in a transgenic mouse model of Pelizaeus-Merzbacher disease
It is widely thought that demyelination contributes to the degeneration of axons and, in combination with acute inflammatory injury, is responsible for progressive axonal loss and persistent clinical disability in inflammatory demyelinating disease. In this study we sought to characterize the relationship between demyelination, inflammation and axonal transport changes using a Plp1-transgenic mouse model of Pelizaeus-Merzbacher disease. In the optic pathway of this non-immune mediated model of demyelination, myelin loss progresses from the optic nerve head towards the brain, over a period of months. Axonal transport is functionally perturbed at sites associated with local inflammation and 'damaged' myelin. Surprisingly, where demyelination is complete, naked axons appear well preserved despite a significant reduction of axonal transport. Our results suggest that neuroinflammation and/or oligodendrocyte dysfunction are more deleterious for axonal health than demyelination per se, at least in the short ter
The Black Hole Mass of NGC 4151. II. Stellar Dynamical Measurement from Near-Infrared Integral Field Spectroscopy
We present a revised measurement of the mass of the central black hole (Mbh)
in the Seyfert 1 galaxy NGC 4151. The new stellar dynamical mass measurement is
derived by applying an axisymmetric orbit-superposition code to near-infrared
integral field data obtained using adaptive optics with the Gemini NIFS
spectrograph. When our models attempt to fit both the NIFS kinematics and
additional low spatial resolution kinematics, our results depend sensitively on
how chi-squared is computed--probably a consequence of complex bar kinematics
that manifest immediately outside the nuclear region. The most robust results
are obtained when only the high spatial resolution kinematic constraints in the
nuclear region are included in the fit. Our best estimates for the BH mass and
H-band mass-to-light ratio are Mbh~(3.76+/-1.15)E7 Msun (1-sigma error) and
M/L(H-band)~0.34+/-0.03 Msun/Lsun (3-sigma error), respectively (the quoted
errors reflect the model uncertainties). Our BH mass measurement is consistent
with estimates from both reverberation mapping (3.57[+0.45/-0.37]E7 Msun) and
gas kinematics (3.0[+0.75/-2.2]E7 Msun; 1-sigma errors), and our best-fit
mass-to-light ratio is consistent with the photometric estimate of
M/L(H-band)=0.4+/-0.2 Msun/Lsun. The NIFS kinematics give a central bulge
velocity dispersion sigma_c=116+/-3 km/s, bringing this object slightly closer
to the M-sigma relation for quiescent galaxies. Although NGC 4151 is one of
only a few Seyfert 1 galaxies in which it is possible to obtain a direct
dynamical BH mass measurement--and thus, an independent calibration of the
reverberation mapping mass scale--the complex bar kinematics makes it less than
ideally suited for this purpose.Comment: 21 pages, 15 figures. Accepted for publication in Ap
Work in Progress: The RICA Project: Rich, Immediate Critique of Antipatterns in Student Code
Rich, relevant, and immediate student feedback is a core ingredient supporting effective student learning. Feedback is particularly important for introductory computing courses where novice programmers are still learning the basic syntax and semantics of a programming language. Our project is aimed at detecting poor solutions to common problems, termed antipatterns, in student code and providing feedback that guides the student to better solutions. This paper discusses the first year of the project, specifically, the development of a Code Critiquer to detect antipatterns in student code and generate appropriate feedback. This important first step sets-up the project to advance knowledge about novice antipatterns and their detection. The use of these antipatterns and code critiquers in future classroom interventions will help the project improve our understanding of student learning, retention, and self-efficacy
Perceptions, priorities, and project delivery problems in women's and environmental health in Peru: a qualitative study.
BACKGROUND: Women living in low-income and-middle-income countries experience increased exposure and worse effects of environmental threats and climate change. Peru is especially susceptible to a range of environmental exposures, including high levels of pollutants, contamination associated with extractive industries, and flooding exacerbated by the ongoing climate emergency. International policies and movements are increasingly calling for a gendered approach to planetary health. However, little research has been done explicitly examining environmental threats to women's health in Peru. We aimed to understand the current Peruvian research, advocacy, and policy landscape at the environment-gender health nexus. METHODS: We did in-depth semi-structured interviews in Spanish via online Zoom video conferencing (audio only) with key informants from the Peruvian Government, academia, and non-governmental organisations to explore their perception of environmental health threats and priorities, population vulnerability factors, awareness of projects and collaborations on these topics, and the role of gender in their work. We used thematic analysis to compare priorities, gender sensitivity, and barriers and facilitators to delivering successful women's environmental health projects in the country. FINDINGS: Since July 14, 2020, we have interviewed 16 people, with four further interviews planned to take place before the end of May, 2021. Several interviewees mentioned the detrimental role of weak institutions, multilevel corruption, and the absence of interdisciplinarity and intersectorality across programmes and research. Barriers to successful collaboration across organisations and sectors were clearly identified, including funding scandals related to extractive economies, high staff turnovers impairing long-term programme implementation, and machismo culture in both organisations and communities. By contrast, some interviewees highlighted that successful collaborations were instead built on direct relationships, reputation, trust, and transparency. Women's empowerment was also described as important for successful programme delivery, especially in female-led associations. Some interviewees emphasised the so-called invisibilisation of vulnerable groups, such as girls, teenagers, pregnant women, victims of gender-based violence, and LGBTQI people. Existing health inequalities varied by setting and cultural context and were deeply and silently exacerbated by the COVID-19 pandemic. INTERPRETATION: These qualitative findings highlight the multiple and inter-related contextual issues faced by environmentally threatened communities in Peru, and how macrostructural barriers contribute to a paucity of sustainable, gender-oriented, environmental health projects. FUNDING: Partially funded by the UK's Economic and Social Research Council
Circadian Variations in Blood Pressure, Heart Rate, and HR-BP Cross-Correlation Coefficient during Progression of Diabetes Mellitus in Rat
Circadian changes in cardiovascular function during the progression of diabetes mellitus in the diabetes prone rat (BBDP) (n = 8) were studied. Age-matched diabetes-resistant rats (BBDR) served as controls. BP was recorded via telemetry in contiguous 4 hr time periods over 24 hours starting with 12 midnight to 4 am as period zero (P0). Prior to onset of diabetes BP was high at P0, peaked at P2, and then fell again at P3; BP and heart rate (HR) then increased gradually at P4 and leveled off at P5, thereby exhibiting a bipodal rhythm. These patterns changed during long-term diabetes. The cross-correlation coefficient of BP and HR was not significantly different across groups at onset, but it fell significantly at 9 months of duration of diabetes (BBDP: 0.39 ± 0.06; BBDR: 0.65 ± 0.03; P < .05). These results show that changes in circadian cardiovascular rhythms in diabetes mellitus became significant at the late stage of the disease
Supporting well-being in retirement through meaningful social roles: Systematic review of intervention studies
Context The marked demographic change toward greater proportions of older people in developed nations poses significant challenges for health and social care. Several studies have demonstrated an association between social roles in later life and positive health and well-being outcomes. After retiring from work, people may lose roles that provide purpose and social contacts. The outcomes of interventions to promote social roles in retirement have not been systematically reviewed. Methods We examined three research questions: (1) What kinds of intervention have been developed to promote social roles in retirement? (2) How much have they improved perceived roles? (3) Have these roles improved health or well-being? We included those studies that evaluated the provision of social roles; used a control or comparison group; targeted healthy retirement-transition adults who were living in the community; provided an abstract written in English; took place in a highly developed nation; and reported social role, health, or well-being outcomes. We searched eight electronic databases and combined the results with hand searches. Findings Through our searches, we identified 9,062 unique publications and eleven evaluative studies of acceptable quality, which reported seven interventions that met our inclusion criteria. These interventions varied in year of inception and scope, but only two were based outside North America. The studies rarely reported the quality or meaning of roles. Only three studies used random allocation, thus limiting inferences of causality from these studies. Interventions providing explicit roles and using supportive group structures were somewhat effective in improving one or more of the following: life satisfaction, social support and activity, physical health and activity, functional health, and cognition. Conclusions Social role interventions may improve health and well-being for people in retirement transition. Future research should improve the quality of intervention and assessment and look at which interventions are most effective and acceptable in facilitating social roles for diverse older populations. © 2013 Milbank Memorial Fund
Characterization of site-specific vegetation activity in Alaskan wet and dry tundra as related to climate and soil state
We present discrete (2-h resolution) multi-year (2008–2017) in situ measurements of seasonal vegetation growth and soil biophysical properties from two sites on Alaska\u27s North Slope, USA, representing dry and wet sedge tundra. We examine measurements of vertical active soil layer temperature and soil moisture profiles (freeze/thaw status), woody shrub vegetation physiological activity, and meteorological site data to assess interrelationships within (and between) these two study sites. Vegetation phenophases (cold de-hardening start, physiological function start, stem growth start, stem growth end, physiological function end, cold hardening completion) were found to have greater interannual day of year (DOY) occurrence variability at the dry site compared with the wet site. At the dry site, vegetation activity begins on average ~7 days earlier and ends ~11 days earlier. The mean active stem growth window lasts ~54 days for the dry site and ~51 days for the wet site. Vegetation, in both tundra environments, began cold de-hardening functions (warm season prep) prior to atmospheric temperatures warming above 0°C. Similar results were found related to the critical soil freeze/thaw/transition dates; the dry site had a DOY phenophase occurrence range that was 8 days larger than that of the wet site. A longer continuous summer thaw period was captured at the wet site by ~26 days throughout the active layer. In addition, the dry site was measured to have longer spring and fall soil isothermal conditions than the wet site by ~9 and 5 days throughout the active layer. These results show that the dry site\u27s willow shrub vegetation physiology and soil condition phenology is more variable than the wet site. Alongside the in situ data, a remote sensing product from NASA\u27s MEaSUREs program was utilized; our research indicates that the AMSR-derived satellite product is more precise over the wet tundra site with critical date alignment between remote sensing observations and in situ measurements ranging from ~4 to 11 days. Furthermore, the AMSR product was shown to preemptively estimate land surface condition change during the spring transition for both tundra types while lagging during the fall transition and freeze-up periods
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