961 research outputs found
A population of immature cerebellar parallel fibre synapses are insensitive to adenosine but are inhibited by hypoxia
The purine adenosine plays an important role in a number of physiological and pathological processes and is neuroprotective during hypoxia and ischemia. The major effect of adenosine is to suppress network activity via the activation of A1 receptors. Here we report that in immature cerebellar slices, the activation of A1 receptors has variable effects on parallel fibre synaptic transmission, ranging from zero depression to an almost complete abolition of transmission. Concentration–response curves suggest that the heterogeneity of inhibition stems from differences in A1 receptor properties which could include coupling to downstream effectors. There is less variation in the effects of adenosine at parallel fibre synapses in slices from older rats and thus adenosine signalling appears developmentally regulated.
In the cerebellum, hypoxia increases the concentration of extracellular adenosine leading to the activation of A1 receptors (at adenosine-sensitive parallel fibre synapses) and the suppression of glutamate release. It would be predicted that the synapses that were insensitive to adenosine would be less depressed by hypoxia and thus maintain function during metabolic stress. However those synapses which were insensitive to adenosine were rapidly inhibited by hypoxia via a mechanism which was not reversed by blocking A1 receptors. Thus another mechanism must be responsible for the hypoxia-mediated depression at these synapses. These different mechanisms of depression may be important for cell survival and for maintenance of cerebellar function following oxygen starvation
Common method variance: An experimental manipulation
Although common method variance has been a subject of research concern for over fifty years, its influence on study results is still not well understood. Common method variance concerns are frequently cited as an issue in the publication of self-report data; yet, there is no consensus as to when, or if, common method variance creates bias. This dissertation examines common method variance by approaching it from an experimental standpoint. If groups of respondents can be influenced to vary their answers to survey items based upon the presence or absence of procedural remedies, a better understanding of common method variance can be developed. The results of this study supported that common method variance can be manipulated through research design, but not to the same degree for all variables. Further, not all of the proposed remedies resulted in significant changes in the results. In addition, the CFA marker technique was used to determine the extent of common method variance in the data. The results indicated that, while common method variance existed in the data set, it did not do so at such levels as to bias results. Additionally, the results indicated support for the noncongeneric perspective of common method variance in that all items were affected to differential degrees. Taken as a whole, these findings show that while common method variance exists and can potentially cause variance in data, the bias produced is minimal. Further, the results indicate the remedies that are posited to reduce common method variance may be less effective than previous researchers believed
The Feud and Shakespeare's 'Romeo and Juliet': a Reconsideration
Writers on Shakespeare have assumed the genesis and source of Romeo and Juliet to be purely literary, based chiefly on Brooke's 1562 poem, and perhaps Painter's Palace of Pleasure. But is it possible that a set of real English circumstances was the spur, to set the scene and prod Shakespeare's imagination to make use of a thirty-year-old poem, transforming both true story and pedestrian poem into the famous play? For it is possible to identify an English situation containing many of the elements which make up the theme of Romeo and Juliet, some of which are not in Brooke, and to show the links with Shakespeare which mean that he knew the circumstances. These events of 1594-5 could also help to date the play's composition more closely
Pay openness movement: Is it merited? Does it influence more desirable employee outcomes than pay secrecy?
Organizations are currently moving toward increased pay openness in the workplace; thus, it is important to determine the influence pay communication practices (pay secrecy and pay openness) have on employee outcomes and whether the increase in pay openness is merited and more beneficial for organizations. The purpose of this article is to analyze pay communication’s influence on workplace deviance and organizational citizenship behaviors (OCBs). Specifically, pay secrecy practices are hypothesized to influence employees to engage in less OCBs and more workplace deviance. Informational justice and distributive justice perceptions are included as mediators. Pay secrecy leads to greater workplace deviance as well as less OCBs and justice perceptions and thus, inferring the pay openness movement is merited. A Pay Communication scale was developed and validated for this study. Practical implications, limitations, and future research directions are provided
Manipulating Common Method Variance via Experimental Conditions
Research data collected from single respondents may raise concerns regarding common method variance (CMV), which is believed to threaten the validity of findings. The primary concern is that CMV can inflate substantive relationships, such that they appear statistically significant when they are not. Thus, understanding the nature of CMV is critical, especially when one considers the popularity—and sometimes necessity—of using self-report data. Research examining CMV has found conflicting evidence about the impact of CMV. Researchers who believe CMV influences findings have proposed solutions to combat any real or perceived potential bias, including changing survey instructions and using marker variables, but few studies have examined the efficacy of these approaches. The purpose of this study is to examine the impact of these techniques and the nature of CMV using an experimental design. To conduct the experiment, multiple versions of a survey, which vary in their use of the remedial approaches, are utilized to collect data, which resulted in 1,069 usable responses. The experimental design was based on the faking literature and included instructions intended to induce or reduce the levels of CMV. Further, two different marker variables are used to determine the degree to which they create a psychological separation in substantive variables. Correlation analysis and measurement invariance are used to analyze the data. This study posits that, if CMV is a substantial concern for self-report data and these approaches are effective, then findings will differ in surveys that incorporate such approaches from surveys that do not. Results indicate few differences in experimental conditions, meaning that regardless of instructions or marker variable, substantive item correlations remained statistically similar. The results indicate this is likely due to the minimal impact of CMV, given that the proposed methods of correction did not significantly influence research findings. These findings have implications for researchers in that they do not support that CMV, or at least its proposed remedies, significantly alter findings. However, support for the null conclusions, in spite of appropriate statistical power, warrant future research examining the nature and impact of CMV
Implementing Primordial Binaries in Simulations of Star Cluster Formation with a Hybrid MHD and Direct N-Body Method
The fraction of stars in binary systems within star clusters is important for
their evolution, but what proportion of binaries form by dynamical processes
after initial stellar accretion remains unknown. In previous work, we showed
that dynamical interactions alone produced too few low-mass binaries compared
to observations. We therefore implement an initial population of binaries in
the coupled MHD and direct N-body star cluster formation code Torch. We compare
simulations with, and without, initial binary populations and follow the
dynamical evolution of the binary population in both sets of simulations,
finding that both dynamical formation and destruction of binaries take place.
Even in the first few million years of star formation, we find that an initial
population of binaries is needed at all masses to reproduce observed binary
fractions for binaries with mass ratios above the detection limit.
Our simulations also indicate that dynamical interactions in the presence of
gas during cluster formation modify the initial distributions towards binaries
with smaller primary masses, larger mass ratios, smaller semi-major axes and
larger eccentricities. Systems formed dynamically do not have the same
properties as the initial systems, and systems formed dynamically in the
presence of an initial population of binaries differ from those formed in
simulations with single stars only. Dynamical interactions during the earliest
stages of star cluster formation are important for determining the properties
of binary star systems.Comment: 15 pages, 14 figures, submitted to MNRAS and edited to address
positive referee's repor
Absence of Evidence Is Not Evidence of Absence: The Color-Density Relation at Fixed Stellar Mass Persists to z ~ 1
We use data drawn from the DEEP2 Galaxy Redshift Survey to investigate the
relationship between local galaxy density, stellar mass, and rest-frame galaxy
color. At z ~ 0.9, we find that the shape of the stellar mass function at the
high-mass (log (M*/Msun) > 10.1) end depends on the local environment, with
high-density regions favoring more massive systems. Accounting for this stellar
mass-environment relation (i.e., working at fixed stellar mass), we find a
significant color-density relation for galaxies with 10.6 < log(M*/Msun) < 11.1
and 0.75 < z < 0.95. This result is shown to be robust to variations in the
sample selection and to extend to even lower masses (down to log(M*/Msun) ~
10.4). We conclude by discussing our results in comparison to recent works in
the literature, which report no significant correlation between galaxy
properties and environment at fixed stellar mass for the same redshift and
stellar mass domain. The non-detection of environmental dependence found in
other data sets is largely attributable to their smaller samples size and lower
sampling density, as well as systematic effects such as inaccurate redshifts
and biased analysis techniques. Ultimately, our results based on DEEP2 data
illustrate that the evolutionary state of a galaxy at z ~ 1 is not exclusively
determined by the stellar mass of the galaxy. Instead, we show that local
environment appears to play a distinct role in the transformation of galaxy
properties at z > 1.Comment: 10 pages, 5 Figures; Accepted for publication in MNRA
“I’m Not Waving, I’m Drowning”: An Autoethnographical Exploration of Biographical Disruption and Reconstruction During Recovery From Prescribed Benzodiazepine Use
Benzodiazepines are group of drugs used mainly as sedatives, hypnotics, muscle relaxants, and anti-epileptics. Tapering off benzodiazepines is, for some users, a painful, traumatic, and protracted process. In this article, I use an autoethnographic approach, adopting the metaphor of water, to examine heuristically my experience of iatrogenic illness and recovery. I draw on personal journals and blog entries and former users’ narratives to consider the particular form of biographical disruption associated with benzodiazepines and the processes involved in identity reconstruction. I emphasize the role of the online community in providing benzodiazepine users such as myself with a co-cultural community through which to share a voice and make sense of our experiences. I explain how the success stories of former users provided me with the hope that I, the “medical victim,” could become the “victor” and in the process construct a new life and fresh identity
Developing pedagogies that work for Pre-Service and Early Career Teachers to reduce the Attainment Gap in Literacy, Numeracy and Health and Wellbeing. Research Question 3: What other practice or research might assist us in our purpose?
This report contributes to the Scottish Council of Deans of Education project related to the Scottish Attainment Challenge. It presents a literature review that responds to the third research question of the SCDE collaborative project: What other practice or research might assist us in our purpose? The purpose of this phase was to resource professional conversations and thinking in the teacher education sector, and to inform the final trial phase of the project.
A literature search was undertaken using a range of strategies, to identify published accounts of innovative work from beyond Scotland in the following fields: initial teacher education for high poverty settings; pedagogies in literacy, numeracy and health and wellbeing; mentoring and induction. Each group of studies is summarised under themes with their potential for the SAC, ITE programmes and professional learning noted
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