18,655 research outputs found
Perceived Leader Authenticity as an Effective Indicator of Perceived Instructional Leadership Behavior in Middle Level Principals
Problem. No study had been undertaken to examine any relationships which might exist between the two concepts of perceived leader authenticity and the perceived instructional leadership behaviors of middle-level principals.
Method. This ex post facto study obtained data from three groups--supervisors, principals, and teachers--via their responses to two questionnaires: the Leader Authenticity Scale and the Principal Instructional Management Rating Scale. A total of 247 of the teachers, all 10 of the supervisors, and all 10 of the principals returned the surveys. Canonical analysis, and one-, two-, and three-way ANOVA were conducted to test the five null hypotheses. Alpha was set at .05. Selected demographic variables were controlled.
Results. Significant correlation was found to exist between the two instruments as whole entities. There were significant differences between the means of the three subgroups on 9 of the 14 sub-scales. Item analysis of each subscale enriched the interpretation of results. Significant differences between means relative to gender were found on two of the 14 subscales. Significant interaction between teacher age and number of years of working with current principal were found on 2 of 14 subscales. There were significant differences between the means of higher enrollment schools and lower enrollment schools on 6 of 14 subscales.
Conclusions. A good instructional manager is an accountable, highly visible, supervisor of instruction who provides performance incentives to both teachers and learners without manipulation. Teachers have different perceptions about authenticity and instructional management than supervisors and principals. Male teachers have some perceptions different than female teachers. Older teachers with more years of working with the current principal perceived the principal to be more manipulative than other groups did. Teachers in higher enrollment schools have higher perceptions of the frequency or quality of some principal behaviors than teachers from smaller enrollment schools
High temperature constitutive and crack initiation modeling of coated single crystal superalloys
The purpose of this program is to develop life prediction models for anisotropic materials used in gas turbine airfoils. In the base portion of the program, two coated single crystal alloys are being tested. They are PWA 286 overlay coated and PWA 273 aluminide coated PWA 1480 and PWA 286 overlay coated Alloy 185. Viscoplastic constitutive models for these materials are also being developed to predict the cyclic stress-strain histories required for life prediction of the lab specimens and actual airfoil designs
Coupling of non-crossing wave modes in a two-dimensional plasma crystal
We report an experimental observation of coupling of the transverse vertical
and longitudinal in-plane dust-lattice wave modes in a two-dimensional complex
plasma crystal in the absence of mode crossing. A new large diameter rf plasma
chamber was used to suspend the plasma crystal. The observations are confirmed
with molecular-dynamics simulations. The coupling manifests itself in traces of
the transverse vertical mode appearing in the measured longitudinal spectra and
vice versa. We calculate the expected ratio of the trace to the principal mode
with a theoretical analysis of the modes in a crystal with finite temperature
and find good agreement with the experiment and simulations.Comment: 4 figures, 5 pages, accepted for publication in PRL Nov 201
The niche party concept and its measurement
The concept of the niche party has become increasingly popular in analyses of party competition. Yet, existing approaches vary in their definitions and their measurement approaches. We propose using a minimal definition that allows us to compare political parties in terms of their ‘nicheness’. We argue that the conceptual core of the niche party concept is based on issue emphasis and that a niche party emphasizes policy areas neglected by its rivals. Based on this definition, we propose a continuous measure that allows for more fine-grained measurement of a party’s ‘nicheness’ than the dominant, dichotomous approaches and thereby limits the risk of measurement error. Drawing on data collected by the Comparative Manifesto Project, we show that (1) our measure has high face validity and (2) exposes differences among parties that are not captured by alternative, static or dichotomous measures
The accessory bacteriochlorophyll
The primary electron transfer in reaction centers of Rhodobacter sphaeroides is studied by subpicosecond absorption spectroscopy with polarized light in the spectral range of 920-1040 nm. Here the bacteriochlorophyll anion radical has an absorption band while the other pigments of the reaction center have vanishing ground-state absorption. The transient absorption data exhibit a pronounced 0.9-ps kinetic component which shows a strong dichroism. Evaluation of the data yields an angle between the transition moments of the special pair and the species related with the 0.9-ps kinetic component of 26 +/- 8 degrees. This angle compares favorably with the value of 29 degrees expected for the reduced accessory bacteriochlorophyll. Extensive transient absorbance data are fully consistent with a stepwise electron transfer via the accessory bacteriochlorophyll
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Cloning and functional characterisation of avian transcription factor E2A.
BACKGROUND: During B lymphocyte development the E2A gene is a critical regulator of cell proliferation and differentiation. With regards to the immunoglobulin genes the E2A proteins contribute to the regulation of gene rearrangement, expression and class switch recombination. We are now using the chicken cell line DT40 as a model system to further analyse the function of E2A. RESULTS: Here we report the cloning and functional analysis of the transcription factor E2A from chicken. Using RACE PCR on the chicken lymphoma cell line DT40 we have isolated full-length clones for the two E2A splice variants E12 and E47. Sequence conservation between the human and chicken proteins is extensive: the basic-helix-loop-helix DNA binding domain of human and chicken E47 and E12 are 93% and 92% identical, respectively. In addition high levels of conservation are seen in activation domain I, the potential NLS and the ubiquitin ligase interaction domain. E2A is expressed in a variety of tissues in chicken, with higher levels of expression in organs rich in immune cells. We demonstrate that chicken E12 and E47 proteins are strong transcriptional activators whose function depends on the presence of activation domain I. As in mammals, the dominant negative proteins Id1 and Id3 can inhibit the function of chicken E47. CONCLUSIONS: The potential for homologous recombination in DT40 allows the genetic dissection of biochemical pathways in somatic cells. With the cloning of avian E2A and the recent description of an in vitro somatic hypermutation assay in this cell line, it should now be possible to dissect the potential role of E2A in the regulation of somatic hypermutation and gene conversion.RIGHTS : This article is licensed under the BioMed Central licence at http://www.biomedcentral.com/about/license which is similar to the 'Creative Commons Attribution Licence'. In brief you may : copy, distribute, and display the work; make derivative works; or make commercial use of the work - under the following conditions: the original author must be given credit; for any reuse or distribution, it must be made clear to others what the license terms of this work are
Impact of tunnel barrier strength on magnetoresistance in carbon nanotubes
We investigate magnetoresistance in spin valves involving CoPd-contacted
carbon nanotubes. Both temperature and bias voltage dependence clearly indicate
tunneling magnetoresistance as the origin. We show that this effect is
significantly affected by the tunnel barrier strength, which appears to be one
reason for the variation between devices previously detected in similar
structures. Modeling the data by means of the scattering matrix approach, we
find a non-trivial dependence of the magnetoresistance on the barrier strength.
Furthermore, analysis of the spin precession observed in a nonlocal Hanle
measurement yields a spin lifetime of ns, a value comparable
with those found in silicon- or graphene-based spin valve devices.Comment: 10 pages, 5 figures, 1 tabl
The media’s gatekeeping function means that party press coverage often reproduces and reinforces existing power structures
In election campaigns, parties and candidates want to get their message across to the public, and the central means of doing so is by generating media coverage. Yet, the media does not slavishly pay attention to each party’s campaign messages. Which actors are most likely to hit the media? And which campaign messages are most likely to make the news? Thomas M. Meyer, Martin Haselmayer and Markus Wagner present research which shows that parties are in general rather successful in getting their messages to the media. However, the media’s gatekeeping function also reproduces existing distributions of power and attention: party messages are most likely to be covered if messages are spread by powerful politicians and if they fit with the current media issue agenda
Why voters do not (always) punish government parties for corruption
Fighting corruption is a vital aspect of good governance. Yet, it is also a highly persistent phenomenon, indicating that tackling corruption is not always at the top of incumbent’s agenda. One way to solve this problem is to engage in corruption performance voting; that is, to use elections to punish incumbents for high levels of corruption. But do citizens actually engage in this kind of voting behavior? Alejandro Ecker, Konstantin Glinitzer and Thomas M. Meyer show that while some voters do engage in corruption performance voting, the segment of voters that are willing to hold incumbents accountable is limited by their partisan preferences, their expectations about future governments, and by the characteristics of the country they live in
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