2,115 research outputs found
A Study Strategies Self-Efficacy Instrument for Use with Community College Students
Theories of self-efficacy and self-regulation were used to examine scores from an instrument that measures self-efficacy for using self-regulatory study strategies. The authors investigated the dimensionality of responses to the Study Skills Self-Efficacy Scale using exploratory factor analysis and Rasch measurement. They also investigated the utility of the Rasch measures in differentiating between groups of students who report being academically successful or at risk. The participants were 550 social science students at a midsized northeastern community-technical college. Results indicated that responses define three related dimensions and that measures were able to differentiate between students reporting to be academically successful or at risk. Additional items need to be developed to increase measurement precision along various portions of the self-efficacy dimensions.Yeshttps://us.sagepub.com/en-us/nam/manuscript-submission-guideline
Candidate X-ray-Emitting OB Stars in the Carina Nebula Identified Via Infrared Spectral Energy Distributions
We report the results of a new survey of massive, OB stars throughout the
Carina Nebula using the X-ray point source catalog provided by the Chandra
Carina Complex Project (CCCP) in conjunction with infrared (IR) photometry from
the Two Micron All-Sky Survey and the Spitzer Space Telescope Vela--Carina
survey. Mid-IR photometry is relatively unaffected by extinction, hence it
provides strong constraints on the luminosities of OB stars, assuming that
their association with the Carina Nebula, and hence their distance, is
confirmed. We fit model stellar atmospheres to the optical (UBV) and IR
spectral energy distributions (SEDs) of 182 OB stars with known spectral types
and measure the bolometric luminosity and extinction for each star. We find
that the extinction law measured toward the OB stars has two components:
Av=1--1.5 mag produced by foreground dust with a ratio of total-to-selective
absorption Rv=3.1 plus a contribution from local dust with Rv>4.0 in the Carina
molecular clouds that increases as Av increases. Using X-ray emission as a
strong indicator of association with Carina, we identify 94 candidate OB stars
with Lbol\geq10^4 Lsun by fitting their IR SEDs. If the candidate OB stars are
eventually confirmed by follow-up spectroscopic observations, the number of
cataloged OB stars in the Carina Nebula will increase by ~50%. Correcting for
incompleteness due to OB stars falling below the Lbol cutoff or the CCCP
detection limit, these results potentially double the size of the young massive
stellar population.Comment: 19 pages, 8 figures, accepted for the ApJS Special Issue on the
Chandra Carina Complex Project (CCCP), scheduled for publication in May 2011.
All 16 CCCP Special Issue papers, including a version of this article with
high-quality figures, are available at
http://cochise.astro.psu.edu/Carina_public/special_issue.html (through 2011
at least
Long-term photometry and periods for 261 nearby pulsating M giants
We present the results of a 5.5-year CCD photometric campaign that monitored
261 bright, southern, semi-regular variables with relatively precise Hipparcos
parallaxes. The data are supplemented with independent photoelectric
observations of 34 of the brightest stars, including 11 that were not part of
the CCD survey, and a previously unpublished long time-series of VZ Cam.
Pulsation periods and amplitudes are established for 247 of these stars, the
majority of which have not been determined before. All M giants with sufficient
observations for period determination are found to be variable, with 87% of the
sample (at S/N >= 7.5) exhibiting multi-periodic behaviour. The period ratios
of local SRVs are in excellent agreement with those in the Large Magellanic
Cloud. Apparent K-band magnitudes are extracted from multiple NIR catalogues
and analysed to determine the most reliable values. We review the effects of
interstellar and circumstellar extinction and calculate absolute K-band
magnitudes using revised Hipparcos parallaxes.Comment: 18 pages, 15 figures; accepted for publication in Monthly Notices of
the Royal Astronomical Societ
Transit timing variation and activity in the WASP-10 planetary system
Transit timing analysis may be an effective method of discovering additional
bodies in extrasolar systems which harbour transiting exoplanets. The
deviations from the Keplerian motion, caused by mutual gravitational
interactions between planets, are expected to generate transit timing
variations of transiting exoplanets. In 2009 we collected 9 light curves of 8
transits of the exoplanet WASP-10b. Combining these data with published ones,
we found that transit timing cannot be explained by a constant period but by a
periodic variation. Simplified three-body models which reproduce the observed
variations of timing residuals were identified by numerical simulations. We
found that the configuration with an additional planet of mass of 0.1
and orbital period of 5.23 d, located close to the outer 5:3
mean motion resonance, is the most likely scenario. If the second planet is a
transiter, the estimated flux drop will be 0.3 per cent and can be
observable with a ground-based telescope. Moreover, we present evidence that
the spots on the stellar surface and rotation of the star affect the radial
velocity curve giving rise to spurious eccentricity of the orbit of the first
planet. We argue that the orbit of WASP-10b is essentially circular. Using the
gyrochronology method, the host star was found to be Myr old. This
young age can explain the large radius reported for WASP-10b.Comment: MNRAS accepte
Dissociation constants and thermodynamic properties of amino acids used in CO2 absorption from (293 to 353) K
The second dissociation constants of the amino acids βalanine, taurine, sarcosine, 6-aminohexanoic acid, DL-methionine, glycine, L-phenylalanine, and L-proline and the third dissociation constants of L-glutamic acid and L-aspartic acid have been determined from electromotive force measurements at temperatures from (293 to 353) K. Experimental results are reported and compared to literature values. Values of the standard state thermodynamic properties are derived from the experimental results and compared to the values of commercially available amines used as absorbents for CO 2 capture.
The importance of quantum decoherence in brain processes
Based on a calculation of neural decoherence rates, we argue that that the
degrees of freedom of the human brain that relate to cognitive processes should
be thought of as a classical rather than quantum system, i.e., that there is
nothing fundamentally wrong with the current classical approach to neural
network simulations. We find that the decoherence timescales ~10^{-13}-10^{-20}
seconds are typically much shorter than the relevant dynamical timescales
(~0.001-0.1 seconds), both for regular neuron firing and for kink-like
polarization excitations in microtubules. This conclusion disagrees with
suggestions by Penrose and others that the brain acts as a quantum computer,
and that quantum coherence is related to consciousness in a fundamental way.Comment: Minor changes to match accepted PRE version. 15 pages with 5 figs
included. Color figures and links at
http://www.physics.upenn.edu/~max/brain.html or from [email protected].
Physical Review E, in pres
Functional Interaction of Nuclear Domain 10 and Its Components with Cytomegalovirus after Infections: Cross-Species Host Cells versus Native Cells
Species-specificity is one of the major characteristics of cytomegaloviruses (CMVs) and is the primary reason for the lack of a mouse model for the direct infection of human CMV (HCMV). It has been determined that CMV cross-species infections are blocked at the post-entry level by intrinsic cellular defense mechanisms, but few details are known. It is important to explore how CMVs interact with the subnuclear structure of the cross-species host cell. In our present study, we discovered that nuclear domain 10 (ND10) of human cells was not disrupted by murine CMV (MCMV) and that the ND10 of mouse cells was not disrupted by HCMV, although the ND10-disrupting protein, immediate-early protein 1 (IE1), also colocalized with ND10 in cross-species infections. In addition, we found that the UL131-repaired HCMV strain AD169 (vDW215-BADrUL131) can infect mouse cells to produce immediate-early (IE) and early (E) proteins but that neither DNA replication nor viral particles were detectable in mouse cells. Unrepaired AD169 can express IE1 only in mouse cells. In both HCMV-infected mouse cells and MCMV-infected human cells, the knocking-down of ND10 components (PML, Daxx, and SP100) resulted in significantly increased viral-protein production. Our observations provide evidence to support our hypothesis that ND10 and ND10 components might be important defensive factors against the CMV cross-species infection
B -> X_s gamma in Supersymmetry with Explicit CP Violation
We discuss B -> X_s gamma decay in both constrained and unconstrained
supersymmetric models with explicit CP violation within the minimal flavor
violation scheme by including tan(beta) -enhanced large contributions beyond
the leading order. In this analysis, we take into account the relevant
cosmological and collider bounds, as well as electric dipole moment
constraints. In the unconstrained model, there are portions of the parameter
space yielding a large CP asymmetry at leading order (LO). In these regions, we
find that the CP phases satisfy certain sum rules, e.g., the sum of the phases
of the \mu parameter and the stop trilinear coupling centralize around \pi with
a width determined by the experimental bounds. In addition, at large values of
tan(beta), the sign of the CP asymmetry tracks the sign of the gluino mass, and
the CP asymmetry is significantly larger than the LO prediction. In the
constrained minimal supersymmetric standard model based on minimal
supergravity, we find that the decay rate is sensitive to the phase of the
universal trilinear coupling. This sensitivity decreases at large values of the
universal gauino mass. We also show that for a given set of the mass
parameters, there exists a threshold value of the phase of the universal
trilinear coupling which grows with tan(beta) and beyond which the experimental
bounds are satisfied. In both supersymmetric scenarios, the allowed ranges of
the CP phases are wide enough to have phenomenological consequences.Comment: 25 pages, 11 figures. Added references, made minor changes in the
text; journal versio
Evaluating the multiple benefits of a Blue-Green Vision for urban surface water management
A Blue-Green City aims to recreate a naturally-oriented water cycle while contributing to the amenity of the city by bringing water management and green infrastructure together. The Blue-Green approach is more than a stormwater management strategy aimed at improving water quality and providing flood risk benefits. It can also provide important ecosystem services, socio-cultural benefits and adaptability to future (uncertain) changes in climate and landuse. However, quantitative evaluation of the benefits, their spatial distribution and co-dependencies are not well understood. The Blue-Green Cities Research Consortium has adopted an interdisciplinary approach to quantitatively evaluate the benefits of Blue-Green infrastructure (BGI) and their relative significance. A new ArcGIS evaluation tool has been developed which can identify the spatial distribution of different benefits and normalise benefits onto a uniform scale. This allows the local impact of multiple benefit types, benefit dependencies and dis-benefits to be directly compared, helping decision makers to co-optimise the benefits from the outset of project planning. The tool was successfully piloted in 2014 in Portland, Oregon, a city with a Blue-Green Vision and extensive investment in green infrastructure, primarily to help reduce the number of combined sewer overflows and improve water quality. This paper also reports on the application of the benefit evaluation tool in Newcastle (UK). Here, hydrodynamic models have been developed to simulate pluvial flood inundation and the movement of water through BGI. An overland flow model has been integrated with the subsurface drainage network to handle discontinuous free surface and pressurised flows. This allows the simulation of mixed flows in pipes and realistic modelling of sewer outflow events. A hypothetical future is presented for a residential area of Newcastle where all pavements and back-alleyways have permeable paving and all gardens are greenspace. Modelling shows that the BGI provides temporary storage and helps alleviate the burden on the subsurface system. The Blue-Green Vision for Newcastle was developed by the Learning and Action Alliance (LAA), an open arrangement where participants create a joint understanding of a problem and its possible solutions based on rational criticism and discussion. The LAA encourages cooperation between a diverse range of stakeholders from different disciplines and backgrounds, including local authorities, major landowners, water companies, academia and environmental groups, and represents a novel approach to facilitate the negotiation of a Blue-Green Vision that addresses strategic objectives, public realm improvements and, not least, the management of urban surface water
Measurement of (anti)deuteron and (anti)proton production in DIS at HERA
The first observation of (anti)deuterons in deep inelastic scattering at HERA
has been made with the ZEUS detector at a centre-of-mass energy of 300--318 GeV
using an integrated luminosity of 120 pb-1. The measurement was performed in
the central rapidity region for transverse momentum per unit of mass in the
range 0.3<p_T/M<0.7. The particle rates have been extracted and interpreted in
terms of the coalescence model. The (anti)deuteron production yield is smaller
than the (anti)proton yield by approximately three orders of magnitude,
consistent with the world measurements.Comment: 26 pages, 9 figures, 5 tables, submitted to Nucl. Phys.
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