4,290 research outputs found
Role of Activity in Human Dynamics
The human society is a very complex system; still, there are several
non-trivial, general features. One type of them is the presence of power-law
distributed quantities in temporal statistics. In this Letter, we focus on the
origin of power-laws in rating of movies. We present a systematic empirical
exploration of the time between two consecutive ratings of movies (the
interevent time). At an aggregate level, we find a monotonous relation between
the activity of individuals and the power-law exponent of the interevent-time
distribution. At an individual level, we observe a heavy-tailed distribution
for each user, as well as a negative correlation between the activity and the
width of the distribution. We support these findings by a similar data set from
mobile phone text-message communication. Our results demonstrate a significant
role of the activity of individuals on the society-level patterns of human
behavior. We believe this is a common character in the interest-driven human
dynamics, corresponding to (but different from) the universality classes of
task-driven dynamics.Comment: 5 pages, 6 figures. Accepted by EP
Ogbu and the debate on educational achievement: an exploration of the links between education, migration, identity and belonging
This paper looks at some of the issues raised by Ogbuâs work in relation to the education of different minority ethnic groups. Ogbu poses questions such as the value attached to education,
its links to the future and its measurable outcomes in terms of âsuccessâ as experienced by black participants. The desire for better life chances leads families to consider migration to a new country or resettlement within the same country, thus making migration both a local and a global phenomenon. As an example, attention is drawn to the situation facing South Asian
children and their families in the UK. In terms of ethnicity and belonging, the wider question that is significant for many countries in the West after âNine-Elevenâ is the education of Muslim children. A consideration of this current situation throws Ogbuâs identification of âautonomous minorityâ into question. It is argued that a greater understanding of diverse needs has to be
accompanied by a concerted effort to confront racism and intolerance in schools and in society, thus enabling all communities to make a useful contribution and to avoid the âriskâ of failure and disenchantment
Discrimination of sonographically detected breast masses using frequency shift color Doppler imaging in combination with age and gray scale criteria.
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/135358/1/jum2001204343.pd
Mini workshop - Real World Engineering Projects: Discovery-based curriculum modules for first-year students
This mini workshop is organized to provide an interactive forum for the introduction a set of six new curriculum modules developed under IEEE's Real World Engineering Projects (RWEP) program. The modules, which are representative of a larger collection of curriculum modules available to the public via an open-access RWEP web portal, are designed for use in the first-year engineering and computer science classroom, and are hands-on, team-based projects that emphasize the societal impact of the work that engineers do. After a brief introduction to the RWEP program and the six showcased curriculum modules, the authors of the modules will present their ideas and demonstrate the laboratory activities associated with their modules in interactive, informal simultaneous sessions. © 2010 IEEE.published_or_final_versionThe 40th ASEE/IEEE Frontiers in Education Conference (FIE) 2010, Arlington, VA., 27-30 October 2010. In Proceedings of 40th FIE, 2010, p. T2A1-T2A
Mini workshop - Real World Engineering Projects: Discovery-based curriculum modules for first-year students
This mini workshop is organized to provide an interactive forum for the introduction a set of six new curriculum modules developed under IEEE's Real World Engineering Projects (RWEP) program. The modules, which are representative of a larger collection of curriculum modules available to the public via an open-access RWEP web portal, are designed for use in the first-year engineering and computer science classroom, and are hands-on, team-based projects that emphasize the societal impact of the work that engineers do. After a brief introduction to the RWEP program and the six showcased curriculum modules, the authors of the modules will present their ideas and demonstrate the laboratory activities associated with their modules in interactive, informal simultaneous sessions. © 2010 IEEE.published_or_final_versionThe 40th ASEE/IEEE Frontiers in Education Conference (FIE) 2010, Arlington, VA., 27-30 October 2010. In Proceedings of 40th FIE, 2010, p. T2A1-T2A
Circulating Brain-Injury Markers After Surgery for Craniosynostosis
Objective: Historically, there have been few quantitative methods for effectively evaluating outcomes after surgery for craniosynostosis. In this prospective study, we assessed a novel approach for detecting possible postsurgery brain injury in patients with craniosynostosis. Methods: We included consecutive patients operated on for sagittal (pi-plasty or craniotomy combined with springs) or metopic (frontal remodeling) synostosis at the Craniofacial Unit at Sahlgrenska University Hospital, Gothenburg, Sweden, from January 2019 to September 2020. Plasma concentrations of the brain-injury biomarkers neurofilament light (NfL), glial fibrillary acidic protein (GFAP), and tau were measured immediately before induction of anesthesia, immediately before and after surgery, and on the first and the third postoperative days using single-molecule array assays. Results: Of the 74 patients included, 44 underwent craniotomy combined with springs for sagittal synostosis, 10 underwent pi-plasty for sagittal synostosis, and 20 underwent frontal remodeling for metopic synostosis. Compared with baseline, GFAP level showed a maximal significant increase at day 1 after frontal remodeling for metopic synostosis and pi-plasty (P = 0.0004 and P = 0.003, respectively). By contrast, craniotomy combined with springs for sagittal synostosis showed no increase in GFAP. For neurofilament light, we found a maximal significant increase at day 3 after surgery for all procedures, with significantly higher levels observed after frontal remodeling and pi-plasty compared with craniotomy combined with springs (P < 0.001). Conclusions: These represent the first results showing significantly increased plasma levels of brain-injury biomarkers after surgery for craniosynostosis. Furthermore, we found that more extensive cranial vault procedures resulted in higher levels of these biomarkers relative to less extensive procedures
HATS-6b: A Warm Saturn Transiting an Early M Dwarf Star, and a Set of Empirical Relations for Characterizing K and M Dwarf Planet Hosts
We report the discovery by the HATSouth survey of HATS-6b, an extrasolar
planet transiting a V=15.2 mag, i=13.7 mag M1V star with a mass of 0.57 Msun
and a radius of 0.57 Rsun. HATS-6b has a period of P = 3.3253 d, mass of
Mp=0.32 Mjup, radius of Rp=1.00 Rjup, and zero-albedo equilibrium temperature
of Teq=712.8+-5.1 K. HATS-6 is one of the lowest mass stars known to host a
close-in gas giant planet, and its transits are among the deepest of any known
transiting planet system. We discuss the follow-up opportunities afforded by
this system, noting that despite the faintness of the host star, it is expected
to have the highest K-band S/N transmission spectrum among known gas giant
planets with Teq < 750 K. In order to characterize the star we present a new
set of empirical relations between the density, radius, mass, bolometric
magnitude, and V, J, H and K-band bolometric corrections for main sequence
stars with M < 0.80 Msun, or spectral types later than K5. These relations are
calibrated using eclipsing binary components as well as members of resolved
binary systems. We account for intrinsic scatter in the relations in a
self-consistent manner. We show that from the transit-based stellar density
alone it is possible to measure the mass and radius of a ~0.6 Msun star to ~7%
and ~2% precision, respectively. Incorporating additional information, such as
the V-K color, or an absolute magnitude, allows the precision to be improved by
up to a factor of two.Comment: 21 pages, 11 figures, 10 tables. Submitted to AJ. Data available at
http://hatsouth.org Code implementing empirical model available at
http://www.astro.princeton.edu/~jhartman/kmdwarfparam.htm
Direct Confirmation of the Asymmetry of the Cas A Supernova with Light Echoes
We report the first detection of asymmetry in a supernova (SN) photosphere
based on SN light echo (LE) spectra of Cas A from the different perspectives of
dust concentrations on its LE ellipsoid. New LEs are reported based on
difference images, and optical spectra of these LEs are analyzed and compared.
After properly accounting for the effects of finite dust-filament extent and
inclination, we find one field where the He I and H alpha features are
blueshifted by an additional ~4000 km/s relative to other spectra and to the
spectra of the Type IIb SN 1993J. That same direction does not show any shift
relative to other Cas A LE spectra in the Ca II near-infrared triplet feature.
We compare the perspectives of the Cas A LE dust concentrations with recent
three-dimensional modeling of the SN remnant (SNR) and note that the location
having the blueshifted He I and H alpha features is roughly in the direction of
an Fe-rich outflow and in the opposite direction of the motion of the compact
object at the center of the SNR. We conclude that Cas A was an intrinsically
asymmetric SN. Future LE spectroscopy of this object, and of other historical
SNe, will provide additional insight into the connection of explosion mechanism
to SN to SNR, as well as give crucial observational evidence regarding how
stars explode.Comment: 13 pages, 7 figures, accepted for publication in Ap
HATS-11b and HATS-12b: Two transiting Hot Jupiters orbiting sub-solar metallicity stars selected for the K2 Campaign 7
We report the discovery of two transiting extrasolar planets from the
HATSouth survey. HATS-11, a V=14.1 G0-star shows a periodic 12.9 mmag dip in
its light curve every 3.6192 days and a radial velocity variation consistent
with a Keplerian orbit. HATS-11 has a mass of 1.000 0.060 M, a
radius of 1.444 0.057 M and an effective temperature of 6060
150 K, while its companion is a 0.85 0.12 M, 1.510 0.078
R planet in a circular orbit. HATS-12 shows a periodic 5.1 mmag flux
decrease every 3.1428 days and Keplerian RV variations around a V=12.8 F-star.
HATS-12 has a mass of 1.489 0.071 M, a radius of 2.21
0.21 R, and an effective temperature of 6408 75 K. For HATS-12,
our measurements indicate that this is a 2.38 0.11 M, 1.35 0.17
R planet in a circular orbit. Both host stars show sub-solar metallicity of
-0.390 0.060 dex and -0.100 0.040 dex, respectively and are
(slightly) evolved stars. In fact, HATS-11 is amongst the most metal-poor and,
HATS-12 is amongst the most evolved stars hosting a hot Jupiter planet.
Importantly, HATS-11 and HATS-12 have been observed in long cadence by Kepler
as part of K2 campaign 7 (EPIC216414930 and EPIC218131080 respectively).Comment: 14 pages, 7 figures, 6 tables, submitted to A
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