6,791 research outputs found
Development and Validation of the Frost Multidimensional Perfectionism ScaleâBrief
Twenty-five years ago, one of the first empirically validated measures of perfectionism, the Frost et al. Multidimensional Perfectionism Scale (F-MPS) was published. Since that time, psychometric studies of the original F-MPS have provided a plethora of evidence to support the potential development of a shorter yet still psychometrically robust version of the measure. Using confirmatory factor analyses across community and clinical samples, the current study identifies an eight-item F-MPS-Brief with two dimensions (i.e., striving and evaluative concerns) that evidences good internal consistency, measurement equivalence across ethnicities, and concurrent and convergent validity. This new, short version of the F-MPS captures well the bidimensional model of perfectionism that has emerged across studies over the past two decades and is suggested for use when a short yet high-performing assessment tool for this model is desired
Lem2p (LEM2) and Cmp7p (CHMP7) function in ESCRT-dependent nuclear envelope remodeling in fission yeast
ESCRTâIII proteins have been implicated in sealing the nuclear envelope in mammals, both during nuclear assembly and following mechanical disruption. This sealing process requires the ESCRTâII/ESCRTâ III hybrid protein CHMP7 and the AAA ATPase VPS4. It remains unclear, however, how
CHMP7 is recruited to breaches of the nuclear envelope. The fission yeast S. pombe is an attractive genetic model system for investigating this role of the ESCRT pathway because, in fission yeast, the nuclear envelope develops fenestrations that must be closed twice per cell cycle: upon mitotic entry when duplicated spindle pole bodies (SPB) are incorporated into the nuclear envelope and
after a successful cell cycle when the SPBs are ejected back to cytoplasm. Here we report that deletion of fission yeast vps4 leads to severe defects in nuclear morphology and integrity, which causes delayed segregation of duplicated SPBs, asymmetric nuclear bipartition in mitosis, and slow growth. Interestingly, these phenotypes are spontaneously suppressed by lossâofâfunction mutations
that arise in cmp7 (pombe CHMP7) or lem2, a member of the LEM (Lap2âEmerinâMan1) family of inner nuclear membrane proteinsâimplying that all three function in the same pathway. Based on these observations, we hypothesize that Lem2p acts as a nuclear siteâspecific adaptor to recruit Cmp7p to the nuclear envelope
Hoarding and Emotional Reactivity: The Link Between Negative Emotional Reactions and Hoarding Symptomatology
Hoarding disorder (HD) is characterized by difficulty discarding, clutter, and frequently excessive acquiring. Theories have pointed to intense negative emotional reactions (e.g., sadness) as one factor that may play a critical role in HD\u27s etiology. Preliminary work with an analogue sample indicated that more intense negative emotions following emotional films were linked with greater hoarding symptoms. Symptom provocation imaging studies with HD patients have also found evidence for excessive activation in brain regions implicated in processing emotions. The current study utilized a sample with self-reported serious hoarding difficulties to examine how hoarding symptoms related to both general and hoarding-related emotional reactivity, taking into account the specificity of these relationships. We also examined how two cognitive factors, fear of decision-making and confidence in memory, modified this relationship. 628 participants with self-identified hoarding difficulties completed questionnaires about general emotional reactivity, depression, anxiety, decision-making, and confidence in memory. To assess hoarding-related emotional reactivity, participants reported their emotional reactions when imagining discarding various items. Heightened general emotional reactivity and more intense emotional reactions to imagined discarding were associated with both difficulty discarding and acquisition, but not clutter, controlling for age, gender, and co-occurring mood and anxiety symptoms. Fear of decision-making and confidence in memory interacted with general emotional reactivity to predict hoarding symptoms. These findings provide support for cognitive-behavioral models of hoarding. Experimental research should be conducted to discover whether emotional reactivity increases vulnerability for HD. Future work should also examine whether emotional reactivity should be targeted in interventions for hoarding
Descriptors for Electron and Hole Charge Carriers in Metal Oxides
Metal oxides can act as insulators, semiconductors, or metals depending on their chemical composition and crystal structure. Metal oxide semiconductors, which support equilibrium populations of electron and hole charge carriers, have widespread applications including batteries, solar cells, and display technologies. It is often difficult to predict in advance whether these materials will exhibit localized or delocalized charge carriers upon oxidation or reduction. We combine data from first-principles calculations of the electronic structure and dielectric response of 214 metal oxides to predict the energetic driving force for carrier localization and transport. We assess descriptors based on the carrier effective mass, static polaron binding energy, and Fröhlich electronâphonon coupling. Numerical analysis allows us to assign p- and n-type transport of a metal oxide to three classes: (i) band transport with high mobility; (ii) small polaron transport with low mobility; and (iii) intermediate behavior. The results of this classification agree with observations regarding carrier dynamics and lifetimes and are used to predict 10 candidate p-type oxides
Stellar and circumstellar evolution of long period variable stars
In a first paper, HIPPARCOS astrometric and kinematic data were used to
calibrate both infrared K and IRAS luminosities at the same time as kinematic
parameters of Long Period Variable stars (LPVs). Individual estimated absolute
magnitudes and a probabilistic assignation to galactic populations were deduced
from these calibrations for each LPV of our sample. Here we propose a scenario
of simultaneous stellar and circumstellar evolution according to the galactic
populations. The transitory states of S and Tc stars allow us to confirm the
location of the first dredge-up at . There is also evidence
suggesting that a previous enrichment in s-elements from a more evolved
companion may accelerate the evolution along the AGB. The possible evolution to
OH LPVs is included in this scenario, and any of these stars may have a mass at
the limit of the capability for a C enrichment up to C/O > 1.
A list of bright massive LPVs with peculiar envelope and luminosity
properties is proposed as Hot Bottom Burning candidates. The He-shell flash
star, R Cen, is found to be exceptionally bright and could become, before
leaving the AGB, a C-rich LPV brighter than the usual luminosity limit of
carbon stars.Comment: Accepted for publication in Astronomy & Astrophysic
Relations between concurrent hard X-ray sources in solar flares
Context: Solar flares release a large fraction of their energy into
non-thermal electrons, but it is not clear where and how. Bremsstrahlung X-rays
are observed from the corona and chromosphere.
Aims: We aim to characterize the acceleration process by the coronal source
and its leakage toward the footpoints in the chromosphere. The relations
between the sources reflect the geometry and constrict the configuration of the
flare.
Methods: We studied solar flares of GOES class larger than M1 with three or
more hard X-ray sources observed simultaneously in the course of the flare. The
events were observed with the X-ray satellite RHESSI from February 2002 until
July 2005. We used imaging spectroscopy methods to determine the spectral
evolution of each source in each event. The images of all of the five events
show two sources visible only at high energies (footpoints) and one source only
visible at low energies (coronal or looptop source, in two cases situated over
the limb).
Results: We find soft-hard-soft behavior in both, coronal source and
footpoints. The coronal source is nearly always softer than the footpoints. The
footpoint spectra differ significantly only in one event out of five.
Conclusions: The observations are consistent with acceleration in the coronal
source and an intricate connection between the corona and chromosphere.Comment: accepted for publication in A&A, 11 pages, 9 figure
âThe International Teacher Leadership project,â a case of international action research.
Copyright CARNThe paper arises from the International Teacher Leadership project, a research and development project involving researchers and practitioners in 14 European countries. The paper provides a conceptual exploration of the idea of teacher leadership and its role in educational reform, central to which is the idea that teachers, regardless of their level of power and organisational position, can engage in the leadership of enquiry-based development activity aimed at influencing their colleagues and embedding improved practices in their schools. The paper provides an outline of the projectâs methodology which builds on that used in the Carpe Vitam Leadership for Learning project (Frost, 2008a). It is a form of collaborative
action research which is highly developmental and discursive. It seeks to identify principles, strategies and tools that can be applied in a range of cultural settings. The paper includes a thematic analysis of the cultural contexts and policy environments of the participating countries in order to identify the obstacles to teacher leadership and to inform the nature of the support strategies employed
Intermittent random walks for an optimal search strategy: One-dimensional case
We study the search kinetics of an immobile target by a concentration of
randomly moving searchers. The object of the study is to optimize the
probability of detection within the constraints of our model. The target is
hidden on a one-dimensional lattice in the sense that searchers have no a
priori information about where it is, and may detect it only upon encounter.
The searchers perform random walks in discrete time n=0,1,2, ..., N, where N is
the maximal time the search process is allowed to run. With probability \alpha
the searchers step on a nearest-neighbour, and with probability (1-\alpha) they
leave the lattice and stay off until they land back on the lattice at a fixed
distance L away from the departure point. The random walk is thus intermittent.
We calculate the probability P_N that the target remains undetected up to the
maximal search time N, and seek to minimize this probability. We find that P_N
is a non-monotonic function of \alpha, and show that there is an optimal choice
\alpha_{opt}(N) of \alpha well within the intermittent regime, 0 <
\alpha_{opt}(N) < 1, whereby P_N can be orders of magnitude smaller compared to
the "pure" random walk cases \alpha =0 and \alpha = 1.Comment: 19 pages, 5 figures; submitted to Journal of Physics: Condensed
Matter; special issue on Chemical Kinetics Beyond the Textbook: Fluctuations,
Many-Particle Effects and Anomalous Dynamics, eds. K.Lindenberg, G.Oshanin
and M.Tachiy
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