2,025 research outputs found
The Dutch version of the Behavior Rating Inventory of Executive Function-2 (BRIEF-2)
The BRIEF-2 (Gioia et al., 2015) is a widely used questionnaire to measure daily behavior related to executive function behaviors in the home and school environment of children between 5 and 18 years old. The current study was conducted to investigate the psychometric properties of the Dutch version of the BRIEF-2 in a representative Dutch-speaking norm sample. Using methods from classical test theory and network theory, we examined the reliability and validity of the BRIEF-2. The results indicated that the BRIEF-2 can be considered as a valid and reliable questionnaire that provides information on the role of executive function in the childâs and adolescentâs functioning in the home and school environment.</p
The Ellipticity of the Disks of Spiral Galaxies
The disks of spiral galaxies are generally elliptical rather than circular.
The distribution of ellipticities can be fit with a log-normal distribution.
For a sample of 12,764 galaxies from the Sloan Digital Sky Survey Data Release
1 (SDSS DR1), the distribution of apparent axis ratios in the i band is best
fit by a log-normal distribution of intrinsic ellipticities with ln epsilon =
-1.85 +/- 0.89. For a sample of nearly face-on spiral galaxies, analyzed by
Andersen and Bershady using both photometric and spectroscopic data, the best
fitting distribution of ellipticities has ln epsilon = -2.29 +/- 1.04. Given
the small size of the Andersen-Bershady sample, the two distribution are not
necessarily inconsistent. If the ellipticity of the potential were equal to
that of the light distribution of the SDSS DR1 galaxies, it would produce 1.0
magnitudes of scatter in the Tully-Fisher relation, greater than is observed.
The Andersen-Bershady results, however, are consistent with a scatter as small
as 0.25 magnitudes in the Tully-Fisher relation.Comment: 19 pages, 5 figures; ApJ, accepte
The Dependence of Galaxy Shape on Luminosity and Surface Brightness Profile
For a sample of 96,951 galaxies from the Sloan Digital Sky Survey Data
Release 3, we study the distribution of apparent axis ratios as a function of
r-band absolute magnitude and surface brightness profile type. We use the
parameter fracDeV to quantify the profile type (fracDeV = 1 for a de
Vaucouleurs profile; fracDeV = 0 for an exponential profile). When the apparent
axis ratio q_{am} is estimated from the moments of the light distribution, the
roundest galaxies are very bright (M_r \sim -23) de Vaucouleurs galaxies and
the flattest are modestly bright (M_r \sim -18) exponential galaxies. When the
apparent axis ratio q_{25} is estimated from the axis ratio of the 25
mag/arcsec^2 isophote, we find that de Vaucouleurs galaxies are flatter than
exponential galaxies of the same absolute magnitude. For a given surface
brightness profile type, very bright galaxies are rounder, on average, than
fainter galaxies. We deconvolve the distributions of apparent axis ratios to
find the distribution of the intrinsic short-to-long axis ratio gamma, assuming
constant triaxiality T. For all profile types and luminosities, the
distribution of apparent axis ratios is inconsistent with a population of
oblate spheroids, but is usually consistent with a population of prolate
spheroids. Bright galaxies with a de Vaucouleurs profile (M_r < -21.84, fracDeV
> 0.9) have a distribution of q_{am} that is consistent with triaxiality in the
range 0.4 < T < 0.8, with mean intrinsic axis ratio 0.66 < gamma < 0.69. The
fainter de Vaucouleurs galaxies are best fit with prolate spheroids (T = 1)
with mean axis ratio gamma = 0.51.Comment: 32 pages, 12 figures, to appear in Ap
The problem of shot selection in basketball
In basketball, every time the offense produces a shot opportunity the player
with the ball must decide whether the shot is worth taking. In this paper, I
explore the question of when a team should shoot and when they should pass up
the shot by considering a simple theoretical model of the shot selection
process, in which the quality of shot opportunities generated by the offense is
assumed to fall randomly within a uniform distribution. I derive an answer to
the question "how likely must the shot be to go in before the player should
take it?", and show that this "lower cutoff" for shot quality depends
crucially on the number of shot opportunities remaining (say, before the
shot clock expires), with larger demanding that only higher-quality shots
should be taken. The function is also derived in the presence of a
finite turnover rate and used to predict the shooting rate of an
optimal-shooting team as a function of time. This prediction is compared to
observed shooting rates from the National Basketball Association (NBA), and the
comparison suggests that NBA players tend to wait too long before shooting and
undervalue the probability of committing a turnover.Comment: 7 pages, 2 figures; comparison to NBA data adde
The role of anticitrullinated protein antibodies in the early stages of rheumatoid arthritis
Purpose of review
This review provides an update on the recent discoveries on the role of anticitrullinated protein antibodies
(ACPA) in early rheumatoid arthritis (RA).
Recent findings
RA is characterized by an immune response against posttranslationally modified proteins, in particular
citrullinated proteins. Recent studies have found that the ACPA response matures shortly before clinical
disease manifests itself and is characterized by an increase in titre, isotype switching, antigen-recognition
profile, and a change in the Fc-glycosylation pattern. To date, many citrullinated autoantigens have been
identified and novel studies suggest that the human leucocyte antigen class II locus may directly influence
the maturation of the ACPA response via antigen-specific T cells. Clinical studies have demonstrated that
effective treatment of arthritis can lead to reduced ACPA levels or a change in composition of ACPA. In
addition to ACPA, autoantibodies targeting other posttranslational modifications have been identified
and may be associated with disease prognosis.
Summary
Key studies have demonstrated that autoimmunity against citrullinated proteins is already present in
preclinical RA and matures over time. Future studies are required to reveal whether autoantibodies and
the B cells that produce them play a role in disease development or can function as biomarkers for
disease maturation.Pathophysiology and treatment of rheumatic disease
Phase diagram of a Heisenberg spin-Peierls model with quantum phonons
Using a new version of the density-matrix renormalization group we determine
the phase diagram of a model of an antiferromagnetic Heisenberg spin chain
where the spins interact with quantum phonons. A quantum phase transition from
a gapless spin-fluid state to a gapped dimerized phase occurs at a non-zero
value of the spin-phonon coupling. The transition is in the same universality
class as that of a frustrated spin chain, which the model maps to in the
anti-adiabatic limit. We argue that realistic modeling of known spin-Peierls
materials should include the effects of quantum phonons.Comment: RevTeX, 5 pages, 3 eps figures included using epsf. Improved theories
in adiabatic and non-adiabatic regimes give better agreement with DMRG. This
version accepted in Physical Review Letter
Anomalous Spin Dynamics observed by High Frequency ESR in Honeycomb Lattice Antiferromagnet InCu2/3V1/3O3
High-frequency ESR results on the S=1/2 Heisenberg hexagonal antiferromagnet
InCu2/3V1/3O3 are reported. This compound appears to be a rare model substance
for the honeycomb lattice antiferromagnet with very weak interlayer couplings.
The high-temperature magnetic susceptibility can be interpreted by the S=1/2
honeycomb lattice antiferromagnet, and it shows a magnetic-order-like anomaly
at TN=38 K. Although, the resonance field of our high-frequency ESR shows the
typical behavior of the antiferromagnetic resonance, the linewidth of our
high-frequency ESR continues to increase below TN, while it tends to decrease
as the temperature in a conventional three-dimensional antiferromagnet
decreases. In general, a honeycomb lattice antiferromagnet is expected to show
a simple antiferromagnetic order similar to that of a square lattice
antiferromagnet theoretically because both antiferromagnets are bipartite
lattices. However, we suggest that the observed anomalous spin dynamics below
TN is the peculiar feature of the honeycomb lattice antiferromagnet that is not
observed in the square lattice antiferromagnet.Comment: 5 pages, 5 figure
The opposites task: Using general rules to test cognitive flexibility in preschoolers
A brief narrative description of the journal article, document, or resource. Executive functions play an important role in cognitive development, and during the preschool years especially, children's performance is limited in tasks that demand flexibility in their behavior. We asked whether preschoolers would exhibit limitations when they are required to apply a general rule in the context of novel stimuli on every trial (the "opposites" task). Two types of inhibitory processing were measured: response interference (resistance to interference from a competing response) and proactive interference (resistance to interference from a previously relevant rule). Group data show 3-year-olds have difficulty inhibiting prepotent tendencies under these conditions, whereas 5-year-olds' accuracy is near ceiling in the task. (Contains 4 footnotes and 1 table.
1.5 Decades Later: Bearing fruits from the ACR/EULAR exchange Program
Imaging Science & TechnologyApplied Science
New Measures of the Trilemma Hypothesis: Implications for Asia
We develop a new set of indexes of exchange rate stability, monetary policy independence, and financial market openness as the metrics for the trilemma hypothesis. In our exploration, we take a different and more nuanced approach than the previous indexes developed by Aizenman, Chinn, and Ito (2008). We show that the new indexes add up to the value two, supporting the trilemma hypothesis. We locate our sample economies' policy mixes in the famous trilemma triangle - a useful and intuitive way to illustrate the state and evolution of policy mixes. We also examine if the persistent deviation of the sum of the three indexes from the value two indicates an unsustainable policy mix and therefore needs to be corrected by economic disruptions such as economic and financial crises. We obtain several findings. First, such a persistent deviation can occur particularly in emerging economies that later experience an inflation (or potentially a general or a currency) crisis, and dissipates in the postcrisis period. Second, there is no evidence for this type of association between deviations from the trilemma constraint and general, banking, or debt crises. Third, Thailand experienced such a deviation from the trilemma constraint in the period leading to the baht crisis of 1997, but not other East and Southeast Asian economies. This last result suggests that the main cause for the Thai baht crisis was an unsustainable policy mix in the precrisis period, while other affected economies experienced crises mainly due to contagion from Thailand
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