2,648 research outputs found
Use of Prosody and Information Structure in High Functioning Adults with Autism in Relation to Language Ability
Abnormal prosody is a striking feature of the speech of those with Autism spectrum disorder (ASD), but previous reports suggest large variability among those with ASD. Here we show that part of this heterogeneity can be explained by level of language functioning. We recorded semi-spontaneous but controlled conversations in adults with and without ASD and measured features related to pitch and duration to determine (1) general use of prosodic features, (2) prosodic use in relation to marking information structure, specifically, the emphasis of new information in a sentence (focus) as opposed to information already given in the conversational context (topic), and (3) the relation between prosodic use and level of language functioning. We found that, compared to typical adults, those with ASD with high language functioning generally used a larger pitch range than controls but did not mark information structure, whereas those with moderate language functioning generally used a smaller pitch range than controls but marked information structure appropriately to a large extent. Both impaired general prosodic use and impaired marking of information structure would be expected to seriously impact social communication and thereby lead to increased difficulty in personal domains, such as making and keeping friendships, and in professional domains, such as competing for employment opportunities
Combination of linear classifiers using score function -- analysis of possible combination strategies
In this work, we addressed the issue of combining linear classifiers using
their score functions. The value of the scoring function depends on the
distance from the decision boundary. Two score functions have been tested and
four different combination strategies were investigated. During the
experimental study, the proposed approach was applied to the heterogeneous
ensemble and it was compared to two reference methods -- majority voting and
model averaging respectively. The comparison was made in terms of seven
different quality criteria. The result shows that combination strategies based
on simple average, and trimmed average are the best combination strategies of
the geometrical combination
Retired A Stars and Their Companions. III. Comparing the Mass-Period Distributions of Planets Around A-Type Stars and Sun-Like Stars
We present an analysis of ~5 years of Lick Observatory radial velocity
measurements targeting a uniform sample of 31 intermediate-mass subgiants (1.5
< M*/Msun < 2.0) with the goal of measuring the occurrence rate of Jovian
planets around (evolved) A-type stars and comparing the distributions of their
orbital and physical characteristics to those of planets around Sun-like stars.
We provide updated orbital solutions incorporating new radial velocity
measurements for five known planet-hosting stars in our sample; uncertainties
in the fitted parameters are assessed using a Markov Chain Monte Carlo method.
The frequency of Jovian planets interior to 3 AU is 26 (+9,-8)%, which is
significantly higher than the ~5-10% frequency observed around solar-mass
stars. The median detection threshold for our sample includes minimum masses
down to {0.2, 0.3, 0.5, 0.6, 1.3} MJup within {0.1, 0.3, 0.6, 1.0, 3.0} AU. To
compare the properties of planets around intermediate-mass stars to those
around solar-mass stars we synthesize a population of planets based on the
parametric relationship dN ~ M^{alpha}P^{beta} dlnM dlnP, the observed planet
frequency, and the detection limits we derived. We find that the values of
alpha and beta for planets around solar-type stars from Cumming et al. fail to
reproduce the observed properties of planets in our sample at the 4 sigma
level, even when accounting for the different planet occurrence rates. Thus,
the properties of planets around A stars are markedly different than those
around Sun-like stars, suggesting that only a small (~ 50%) increase in stellar
mass has a large influence on the formation and orbital evolution of planets.Comment: Accepted by the Astrophysical Journal; 15 pages, 15 figure
Kepler-16: A Transiting Circumbinary Planet
We report the detection of a planet whose orbit surrounds a pair of low-mass
stars. Data from the Kepler spacecraft reveal transits of the planet across
both stars, in addition to the mutual eclipses of the stars, giving precise
constraints on the absolute dimensions of all three bodies. The planet is
comparable to Saturn in mass and size, and is on a nearly circular 229-day
orbit around its two parent stars. The eclipsing stars are 20% and 69% as
massive as the sun, and have an eccentric 41-day orbit. The motions of all
three bodies are confined to within 0.5 degree of a single plane, suggesting
that the planet formed within a circumbinary disk.Comment: Science, in press; for supplemental material see
http://www.sciencemag.org/content/suppl/2011/09/14/333.6049.1602.DC1/1210923.Doyle.SOM.pd
Recording sympathetic nerve activity in conscious humans and other mammals:guidelines and the road to standardization
Over the past several decades, studies of the sympathetic nervous system in humans, sheep, rabbits, rats, and mice have substantially increased mechanistic understanding of cardiovascular function and dysfunction. Recently, interest in sympathetic neural mechanisms contributing to blood pressure control has grown, in part because of the development of devices or surgical procedures that treat hypertension by manipulating sympathetic outflow. Studies in animal models have provided important insights into physiological and pathophysiological mechanisms that are not accessible in human studies. Across species and among laboratories, various approaches have been developed to record, quantify, analyze, and interpret sympathetic nerve activity (SNA). In general, SNA demonstrates “bursting” behavior, where groups of action potentials are synchronized and linked to the cardiac cycle via the arterial baroreflex. In humans, it is common to quantify SNA as bursts per minute or bursts per 100 heart beats. This type of quantification can be done in other species but is only commonly reported in sheep, which have heart rates similar to humans. In rabbits, rats, and mice, SNA is often recorded relative to a maximal level elicited in the laboratory to control for differences in electrode position among animals or on different study days. SNA in humans can also be presented as total activity, where normalization to the largest burst is a common approach. The goal of the present paper is to put together a summary of “best practices” in several of the most common experimental models and to discuss opportunities and challenges relative to the optimal measurement of SNA across species. Listen to this article's corresponding podcast at https://ajpheart.podbean.com/e/guidelines-for-measuring-sympathetic-nerve-activity/ </jats:p
Planetary Candidates Observed by Kepler, III: Analysis of the First 16 Months of Data
New transiting planet candidates are identified in sixteen months (May 2009 -
September 2010) of data from the Kepler spacecraft. Nearly five thousand
periodic transit-like signals are vetted against astrophysical and instrumental
false positives yielding 1,091 viable new planet candidates, bringing the total
count up to over 2,300. Improved vetting metrics are employed, contributing to
higher catalog reliability. Most notable is the noise-weighted robust averaging
of multi-quarter photo-center offsets derived from difference image analysis
which identifies likely background eclipsing binaries. Twenty-two months of
photometry are used for the purpose of characterizing each of the new
candidates. Ephemerides (transit epoch, T_0, and orbital period, P) are
tabulated as well as the products of light curve modeling: reduced radius
(Rp/R*), reduced semi-major axis (d/R*), and impact parameter (b). The largest
fractional increases are seen for the smallest planet candidates (197% for
candidates smaller than 2Re compared to 52% for candidates larger than 2Re) and
those at longer orbital periods (123% for candidates outside of 50-day orbits
versus 85% for candidates inside of 50-day orbits). The gains are larger than
expected from increasing the observing window from thirteen months (Quarter 1--
Quarter 5) to sixteen months (Quarter 1 -- Quarter 6). This demonstrates the
benefit of continued development of pipeline analysis software. The fraction of
all host stars with multiple candidates has grown from 17% to 20%, and the
paucity of short-period giant planets in multiple systems is still evident. The
progression toward smaller planets at longer orbital periods with each new
catalog release suggests that Earth-size planets in the Habitable Zone are
forthcoming if, indeed, such planets are abundant.Comment: Submitted to ApJS. Machine-readable tables are available at
http://kepler.nasa.gov, http://archive.stsci.edu/kepler/results.html, and the
NASA Exoplanet Archiv
Discovery and Rossiter-McLaughlin Effect of Exoplanet Kepler-8b
We report the discovery and the Rossiter-McLaughlin effect of Kepler-8b, a
transiting planet identified by the NASA Kepler Mission. Kepler photometry and
Keck-HIRES radial velocities yield the radius and mass of the planet around
this F8IV subgiant host star. The planet has a radius RP = 1.419 RJ and a mass,
MP = 0.60 MJ, yielding a density of 0.26 g cm^-3, among the lowest density
planets known. The orbital period is P = 3.523 days and orbital semima jor axis
is 0.0483+0.0006/-0.0012 AU. The star has a large rotational v sin i of 10.5
+/- 0.7 km s^-1 and is relatively faint (V = 13.89 mag), both properties
deleterious to precise Doppler measurements. The velocities are indeed noisy,
with scatter of 30 m s^-1, but exhibit a period and phase consistent with the
planet implied by the photometry. We securely detect the Rossiter-McLaughlin
effect, confirming the planet's existence and establishing its orbit as
prograde. We measure an inclination between the projected planetary orbital
axis and the projected stellar rotation axis of lambda = -26.9 +/- 4.6 deg,
indicating a moderate inclination of the planetary orbit. Rossiter-McLaughlin
measurements of a large sample of transiting planets from Kepler will provide a
statistically robust measure of the true distribution of spin-orbit
orientations for hot jupiters in general.Comment: 26 pages, 8 figures, 2 tables; In preparation for submission to the
Astrophysical Journa
Genome sequence of an Australian kangaroo, Macropus eugenii, provides insight into the evolution of mammalian reproduction and development.
BACKGROUND: We present the genome sequence of the tammar wallaby, Macropus eugenii, which is a member of the kangaroo family and the first representative of the iconic hopping mammals that symbolize Australia to be sequenced. The tammar has many unusual biological characteristics, including the longest period of embryonic diapause of any mammal, extremely synchronized seasonal breeding and prolonged and sophisticated lactation within a well-defined pouch. Like other marsupials, it gives birth to highly altricial young, and has a small number of very large chromosomes, making it a valuable model for genomics, reproduction and development. RESULTS: The genome has been sequenced to 2 × coverage using Sanger sequencing, enhanced with additional next generation sequencing and the integration of extensive physical and linkage maps to build the genome assembly. We also sequenced the tammar transcriptome across many tissues and developmental time points. Our analyses of these data shed light on mammalian reproduction, development and genome evolution: there is innovation in reproductive and lactational genes, rapid evolution of germ cell genes, and incomplete, locus-specific X inactivation. We also observe novel retrotransposons and a highly rearranged major histocompatibility complex, with many class I genes located outside the complex. Novel microRNAs in the tammar HOX clusters uncover new potential mammalian HOX regulatory elements. CONCLUSIONS: Analyses of these resources enhance our understanding of marsupial gene evolution, identify marsupial-specific conserved non-coding elements and critical genes across a range of biological systems, including reproduction, development and immunity, and provide new insight into marsupial and mammalian biology and genome evolution
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