56 research outputs found
Mental Addition in Bilinguals: An fMRI Study of Task-Related and Performance-Related Activation
Behavioral studies show that bilinguals are slower and less accurate when performing mental calculation in their nondominant (second; L2) language than in their dominant (first; L1) language. However, little is known about the neural correlates associated with the performance differences observed between bilinguals' 2 languages during arithmetic processing. To address the cortical activation differences between languages, the current study examined task-related and performance-related brain activation during mental addition when problems were presented auditorily in participants' L1 and L2. Eleven ChineseâEnglish bilinguals heard 2-digit addition problems that required exact or approximate calculations. Functional magnetic resonance imaging results showed that auditorily presented multidigit addition in bilinguals activates bilateral inferior parietal and inferior frontal regions in both L1 and L2. Language differences were observed in the form of greater activation for L2 exact addition in the left inferior frontal area. A negative correlation between brain activation and behavioral performance during mental addition in L2 was observed in the left inferior parietal area. Current results provide further evidence for the effects of language-specific experience on arithmetic processing in bilinguals at the cortical level
Probing the low-redshift star formation rate as a function of metallicity through the local environments of type II supernovae
Type II SNe can trace star formation to probe its global metallicity
distribution at low-redshift. We present oxygen and iron abundance
distributions of SN II progenitor regions that avoid many previous sources of
bias. Because Fe (rather than O) abundance drives the late stage evolution of
the massive stars that are the progenitors of CCSNe, and because Fe enrichment
lags O enrichment, we find a general conversion from O abundance to Fe
abundance. The distributions we present here are the best yet standard of
comparison for evaluating how rare classes of SNe depend on progenitor
metallicity. We measure the gas-phase O abundance of a representative subsample
of the hosts of SNe II from the first-year PTF SN search, using a combination
of SDSS spectra near the SN location (9) and new long slit spectroscopy (25).
The median metallicity of these 34 hosts is 12+log(O/H) = 8.65, with a median
error of 0.09. The median host galaxy stellar mass from fits to SDSS photometry
is 10^9.9 solar masses. They do not show a systematic offset in metallicity or
mass from a redshift-matched sample of the MPA/JHU value-added catalog. In
contrast to previous SN host metallicity studies, this sample is drawn from a
single, areal survey. SNe in the lowest-mass galaxies are not systematically
excluded. The metallicity distribution we find is statistically
indistinguishable from the metallicity distribution of SN II hosts found by
targeted surveys and by samples from multiple surveys with different selection
functions. Using the relationship between Fe and O abundances found for Milky
Way disk, bulge, and halo stars, we translate our O abundance distribution of
SN II environments into Fe abundance estimates. We find that though this sample
spans only 0.65 dex in O abundance, the gap between the Fe and O abundance is
50% wider at the low-metallicity end of our sample than at the high-metallicity
end. (abridged)Comment: 22 pages, 14 figures, 7 tables, ApJ accepte
Fast Winds and Mass Loss from Metal-Poor Field Giants
Spectra of the He I 10830 Angstrom line were obtained with NIRSPEC on the
Keck 2 telescope for metal-deficient field giant stars. This line is ubiquitous
in stars with T_eff greater than 4500K and M_V fainter than -1.5. Fast outflows
are detected from the majority of stars and about 40 percent of the outflows
have sufficient speed to allow escape of material from the star as well as from
a globular cluster. Outflow speeds and line strengths do not depend on
metallicity suggesting the driving mechanism for these winds derives from
magnetic and/or hydrodynamic processes. Gas outflows are present in every
luminous giant, but are not detected in all stars of lower luminosity
indicating possible variability. Mass loss rates ranging from 3X10(-10) to
6X10(-8) solar mass/yr estimated from the Sobolev approximation represent
values with evolutionary significance for red giant branch (RGB) and red
horizontal branch (RHB) stars. We estimate that 0.2 M_sun will be lost on the
RGB, and the torque of this wind can account for observations of slowly
rotating RHB stars in the field. About 0.1-0.2 M_sun will be lost on the RHB
itself. This first empirical determination of mass loss on the RHB may
contribute to the appearance of extended horizontal branches in globular
clusters. The spectra appear to resolve the problem of missing intracluster
material in globular clusters. Opportunities exist for 'wind smothering' of
dwarf stars by winds from the evolved population, possibly leading to surface
pollution in regions of high stellar density.Comment: 53 pages; 15 figures; accepted for publication in The Astronomical
Journa
Review of the cultivation program within the National Alliance for Advanced Biofuels and Bioproducts
The cultivation efforts within the National Alliance for Advanced Biofuels and Bioproducts (NAABB)were developed to provide four major goals for the consortium, which included biomass production for downstream experimentation, development of new assessment tools for cultivation, development of new cultivation reactor technologies, and development of methods for robust cultivation. The NAABB consortium test beds produced over 1500 kg of biomass for downstream processing. The biomass production included a number of model production strains, but also took into production some of the more promising strains found through the prospecting efforts of the consortium. Cultivation efforts at large scale are intensive and costly, therefore the consortium developed tools and models to assess the productivity of strains under various environmental conditions, at lab scale, and validated these against scaled outdoor production systems. Two new pond-based bioreactor designs were tested for their ability to minimize energy consumption while maintaining, and even exceeding, the productivity of algae cultivation compared to traditional systems. Also, molecular markers were developed for quality control and to facilitate detection of bacterial communities associated with cultivated algal species, including the Chlorella spp. pathogen, Vampirovibrio chlorellavorus,which was identified in at least two test site locations in Arizona and New Mexico. Finally, the consortium worked on understanding methods to utilize compromised municipal waste water streams for cultivation. This review provides an overview of the cultivation methods and tools developed by the NAABB consortium to produce algae biomass, in robust low energy systems, for biofuel production
Gender differences in the upward mobility of black managers: Double whammy or double advantage?
This study draws upon the theory and research on intraorganizational mobility to examine gender differences in the upward mobility of black managers. Results suggest that neither the âdouble whammyâ assumptions nor the âdouble advantageâ assumptions are accurate descriptions of the contemporary experience of black female managers in corporate America. Upward mobility rates were nearly identical for both gender groups. Other findings and the implications of the results for future research are discussed.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/45590/1/11199_2004_Article_BF00289811.pd
SDSS-III: Massive Spectroscopic Surveys of the Distant Universe, the Milky Way Galaxy, and Extra-Solar Planetary Systems
Building on the legacy of the Sloan Digital Sky Survey (SDSS-I and II),
SDSS-III is a program of four spectroscopic surveys on three scientific themes:
dark energy and cosmological parameters, the history and structure of the Milky
Way, and the population of giant planets around other stars. In keeping with
SDSS tradition, SDSS-III will provide regular public releases of all its data,
beginning with SDSS DR8 (which occurred in Jan 2011). This paper presents an
overview of the four SDSS-III surveys. BOSS will measure redshifts of 1.5
million massive galaxies and Lya forest spectra of 150,000 quasars, using the
BAO feature of large scale structure to obtain percent-level determinations of
the distance scale and Hubble expansion rate at z<0.7 and at z~2.5. SEGUE-2,
which is now completed, measured medium-resolution (R=1800) optical spectra of
118,000 stars in a variety of target categories, probing chemical evolution,
stellar kinematics and substructure, and the mass profile of the dark matter
halo from the solar neighborhood to distances of 100 kpc. APOGEE will obtain
high-resolution (R~30,000), high signal-to-noise (S/N>100 per resolution
element), H-band (1.51-1.70 micron) spectra of 10^5 evolved, late-type stars,
measuring separate abundances for ~15 elements per star and creating the first
high-precision spectroscopic survey of all Galactic stellar populations (bulge,
bar, disks, halo) with a uniform set of stellar tracers and spectral
diagnostics. MARVELS will monitor radial velocities of more than 8000 FGK stars
with the sensitivity and cadence (10-40 m/s, ~24 visits per star) needed to
detect giant planets with periods up to two years, providing an unprecedented
data set for understanding the formation and dynamical evolution of giant
planet systems. (Abridged)Comment: Revised to version published in The Astronomical Journa
Testing evaluations to the limits: the case of English Health Action Zones
Since the Blair government was elected in Britian in May 1997, there has been an explosion of area-based initiatives aimed at regenerating deprived communities and reducing poverty and social exclusion. All are partnerships that place a high value on collaboration, in contrast to the previous government's faith in competition and quasi-markets. At the same time, these new experiments in 'joined-up government' are expected to put the interests of consumers and communities before the innate conservatism of providers of services. In addition, many of the new area-based initiatives are charged with the responsibility for 'constantly reviewing, evaluating and, where necessary, adapting policies to ensure they achieve the maximum effect
Abnormal Ventral Temporal Cortical Activity During Face Discrimination Among Individuals With Autism and Asperger Syndrome
e for processing faces than the control groups, but for these analyses, the effect was now on the left side. Greater ITG activation was the pattern found in both control groups during object processing. Conclusions: Individuals with autism spectrum disorders demonstrate a pattern of brain activity during face discrimination that is consistent with featurebased strategies that are more typical of nonface object perception. Arch Gen Psychiatry. 2000;57:331-340 T HE SYMPTOMS of autism spectrum disorders, such as a preference for inanimate objects and lack of interest in the human face, are evident as early as the first year of life. 1-3 Abnormalities in face-recognition skills are of particular interest, as they may provide clues about the developmental mechanisms involved in the pathobiology of autism and Asperger syndrome (AS). Recognition of individual faces is necessary for successful interpersonal rela
Using programme theory to strengthen research protocol and intervention design within an RCT of a walking intervention
This article provides a practical example of how to apply a theory-driven approach to research intervention and protocol design. It illustrates how reflection on both intervention theory and programme theory can inform and refine the: implementation of the intervention; research design; specification of research questions and tools; and, identify the contribution each research stage makes in the accumulation of policy-relevant learning. The article presents the logic models, associated theory and learning from the development of a pilot randomized control trial/feasibility study of a walking intervention targeting older adults
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