8,526 research outputs found
Familial influences on the full range of variability in attention and activity levels during adolescence: A longitudinal twin study
AbstractTo investigate familial influences on the full range of variability in attention and activity across adolescence, we collected maternal ratings of 339 twin pairs at ages 12, 14, and 16, and estimated the transmitted and new familial influences on attention and activity as measured by the Strengths and Weaknesses of Attention-Deficit/Hyperactivity Disorder Symptoms and Normal Behavior Scale. Familial influences were substantial for both traits across adolescence: genetic influences accounted for 54%–73% (attention) and 31%–73% (activity) of the total variance, and shared environmental influences accounted for 0%–22% of the attention variance and 13%–57% of the activity variance. The longitudinal stability of individual differences in attention and activity was largely accounted for by familial influences transmitted from previous ages. Innovations over adolescence were also partially attributable to familial influences. Studying the full range of variability in attention and activity may facilitate our understanding of attention-deficit/hyperactivity disorder's etiology and intervention.</jats:p
Trans-Planckian physics and signature change events in Bose gas hydrodynamics
We present an example of emergent spacetime as the hydrodynamic limit of a
more fundamental microscopic theory. The low-energy, long-wavelength limit in
our model is dominated by collective variables that generate an effective
Lorentzian metric. This system naturally exhibits a microscopic mechanism
allowing us to perform controlled signature change between Lorentzian and
Riemannian geometries. We calculate the number of particles produced from a
finite-duration Euclidean-signature event, where we take the position that to a
good approximation the dynamics is dominated by the evolution of the linearized
perturbations, as suggested by Calzetta and Hu [Phys. Rev. A 68 (2003) 043625].
We adapt the ideas presented by Dray et al. [Gen. Rel. Grav. 23 (1991) 967],
such that the field and its canonical momentum are continuous at the
signature-change event.
We investigate the interplay between the underlying microscopic structure and
the emergent gravitational field, focussing on its impact on particle
production in the ultraviolet regime. In general, this can be thought of as the
combination of trans-Planckian physics and signature-change physics. Further we
investigate the possibility of using the proposed signature change event as an
amplifier for analogue "cosmological particle production" in condensed matter
experiments.Comment: 18 pages, revtex
The effect of cultural and environmental factors on potato seed tuber morphology and subsequent sprout and stem development
Seed crops of the variety Estima were grown in each of 2 years using two planting dates, two harvest dates, two plant densities and two irrigation regimes to produce seed tubers which had experienced different cultural and environmental conditions. The effects of these treatments on tuber characteristics, sprout production and stem development in the ware crop were then determined in subsequent experiments using storage regimes of 3 and 10 °C. Time of planting the seed crop affected numbers of eyes, sprouts and above ground stems in the subsequent ware crop because environmental conditions around the time of tuber initiation appeared to alter tuber shape. Cooler, wetter conditions in the 7 days after tuber initiation were associated with tubers which were longer, heavier and had more eyes, sprouts and above ground stems. In contrast, the time of harvesting the seed crop did not affect tuber shape or numbers of above ground stems and there was no interaction with tuber size. The density of the seed crop had no effect on any character measured and irrigation well after tuber initiation did not affect tuber shape, numbers of sprouts or numbers of stems. Seed production treatments, which resulted in earlier dormancy break, were associated with tubers that produced more sprouts and above ground stems, in contrast to the conventional understanding of apical dominance. Storage at 3 °C gave fewer sprouts, a lower proportion of eyes with sprouts and fewer stems than storage at 10 °C. The major effects on stem production appear to result from environmental conditions at the time of tuber initiation of the seed crop and sprouting temperature
Creation and characterization of vortex clusters in atomic Bose-Einstein condensates
We show that a moving obstacle, in the form of an elongated paddle, can
create vortices that are dispersed, or induce clusters of like-signed vortices
in 2D Bose-Einstein condensates. We propose new statistical measures of
clustering based on Ripley's K-function which are suitable to the small size
and small number of vortices in atomic condensates, which lack the huge number
of length scales excited in larger classical and quantum turbulent fluid
systems. The evolution and decay of clustering is analyzed using these
measures. Experimentally it should prove possible to create such an obstacle by
a laser beam and a moving optical mask. The theoretical techniques we present
are accessible to experimentalists and extend the current methods available to
induce 2D quantum turbulence in Bose-Einstein condensates.Comment: 9 pages, 9 figure
Immunoregulatory Potential of Exosomes Derived from Cancer Stem Cells.
Head and neck squamous cell carcinomas (HNSCCs) are malignancies that originate in the mucosal lining of the upper aerodigestive tract. Despite advances in therapeutic interventions, survival rates among HNSCC patients have remained static for years. Cancer stem cells (CSCs) are tumor-initiating cells that are highly resistant to treatment, and are hypothesized to contribute to a significant fraction of tumor recurrences. Consequently, further investigations of how CSCs mediate recurrence may provide insights into novel druggable targets. A key element of recurrence involves the tumor's ability to evade immunosurveillance. Recent published reports suggest that CSCs possess immunosuppressive properties, however, the underlying mechanism have yet to be fully elucidated. To date, most groups have focused on the role of CSC-derived secretory proteins, such as cytokines and growth factors. Here, we review the established immunoregulatory role of exosomes derived from mixed tumor cell populations, and propose further study of CSC-derived exosomes may be warranted. Such studies may yield novel insights into new druggable targets, or lay the foundation for future exosome-based diagnostics
C-Band All-Sky Survey: A First Look at the Galaxy
We present an analysis of the diffuse emission at 5 GHz in the first quadrant
of the Galactic plane using two months of preliminary intensity data taken with
the C-Band All Sky Survey (C-BASS) northern instrument at the Owens Valley
Radio Observatory, California. Combining C-BASS maps with ancillary data to
make temperature-temperature plots we find synchrotron spectral indices of
between 0.408 GHz and 5 GHz and between 1.420 GHz and 5 GHz for ,
. Through the subtraction of a radio recombination
line (RRL) free-free template we determine the synchrotron spectral index in
the Galactic plane () to be between
0.408 GHz and 5 GHz, with a contribution of per cent from free-free
emission at 5\,GHz. These results are consistent with previous low frequency
measurements in the Galactic plane. By including C-BASS data in spectral fits
we demonstrate the presence of anomalous microwave emission (AME) associated
with the HII complexes W43, W44 and W47 near 30 GHz, at 4.4 sigma, 3.1 sigma
and 2.5 sigma respectively. The CORNISH VLA 5 GHz source catalogue rules out
the possibility that the excess emission detected around 30\;GHz may be due to
ultra-compact HII regions. Diffuse AME was also identified at a 4 sigma level
within , between 5
GHz and 22.8 GHz.Comment: 16 pages, 9 figures, submitted to MNRAS, referee's corrections made,
awaiting for final approval for publicatio
Teen Dating Violence: The Influence of Friendships and School Context
Prior research has examined parental and peer influences on teen dating violence (TDV), but fewer studies have explored the role of broader social contexts. Using data from the Toledo Adolescent Relationships Study (TARS), the present research examines the effect of variations in school context on teen dating violence perpetration, while taking into account parental, peer, and demographic factors. Drawing on interview data from 955 adolescents across 32 different schools, results indicate that net of parents’ and friends’ use of violence, the normative climate of schools, specifically school-level teen dating violence, is a significant predictor of respondents’ own violence perpetration. School-level dating norms (non-exclusivity in relationships) also contribute indirectly to the odds of experiencing TDV. However, a more general measure of school-level violence toward friends is not strongly related to variations in TDV, suggesting the need to focus on domain-specific influences. Implications for theories emphasizing social learning processes and for TDV prevention efforts are discussed
The C-Band All-Sky Survey (C-BASS): Constraining diffuse Galactic radio emission in the North Celestial Pole region
The C-Band All-Sky Survey C-BASS is a high-sensitivity all-sky radio survey
at an angular resolution of 45 arcmin and a frequency of 4.7 GHz. We present a
total intensity 4.7 GHz map of the North Celestial Pole (NCP) region of sky,
above declination +80 deg, which is limited by source confusion at a level of
~0.6 mK rms. We apply the template-fitting (cross-correlation) technique to
WMAP and Planck data, using the C-BASS map as the synchrotron template, to
investigate the contribution of diffuse foreground emission at frequencies
~20-40 GHz. We quantify the anomalous microwave emission (AME) that is
correlated with far-infrared dust emission. The AME amplitude does not change
significantly (<10%) when using the higher frequency C-BASS 4.7 GHz template
instead of the traditional Haslam 408 MHz map as a tracer of synchrotron
radiation. We measure template coefficients of and
K per unit when using the Haslam and C-BASS synchrotron templates,
respectively. The AME contributes K rms at 22.8 GHz and accounts
for ~60% of the total foreground emission. Our results suggest that a harder
(flatter spectrum) component of synchrotron emission is not dominant at
frequencies >5 GHz; the best-fitting synchrotron temperature spectral index is
from 4.7 to 22.8 GHz and from 22.8 to
44.1 GHz. Free-free emission is weak, contributing ~K rms (~7%) at 22.8
GHz. The best explanation for the AME is still electric dipole emission from
small spinning dust grains.Comment: 18 pages, 6 figures, version matches version accepted by MNRA
Isolated Medial Cuneiform Fractures: A Systematic Search and Qualitative Analysis of Case Studies
Background: Isolated medial cuneiform fracture is a rare but diagnostically challenging condition. Diagnostic delay in these cases may lead to delays in ideal treatment approaches and prolonged symptoms. An understanding of clinical presentation is needed to expedite diagnosis, facilitate decision making, and guide treatment approach.
Methods: Case studies/series were searched in four databases until September 2019. Included studies had participants with a history of traumatic closed medial cuneiform fracture. Studies were excluded if the medial cuneiform fractures were open fractures, associated with multitrauma, or associated with dislocation/Lisfranc injury. Three blinded reviewers assessed the methodological quality of the studies, and a qualitative synthesis was performed.
Results: Ten studies comprising 15 patients were identified. Mean ± SD patient age was 38.0 ± 12.8 years, with 86.7% of reported participants being men. The overall methodological quality was moderate to high, and reporting of the patient selection criteria was poor overall. The most commonly reported clinical symptoms were localized tenderness (60.0%) and edema (53.3%). Direct blow was the most common inciting trauma (46.2%), followed by axial load (30.8%) and avulsion injuries (23.1%). Baseline radiographs were occult in 72.7% of patients; magnetic resonance imaging and computed tomography were the most common diagnostic modalities. Mean ± SD diagnostic delay was 64.7 ± 89.6 days. Conservative management was pursued in 54.5% of patients, with reported resolution of symptoms in 3 to 6 months. Surgical intervention occurred in 45.5% of patients and resulted in functional restoration in 3 to 6 months in all but one patient.
Conclusions: Initial radiographs for isolated medial cuneiform fractures are frequently occult. Due to expedience and relatively low cost, radiographs are still a viable first-line imaging modality. If clinical concern remains, magnetic resonance imaging may be pursued to minimize diagnostic delay. Conservative management is a viable treatment method, with expected return to full function in 3 to 6 months
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