1,280 research outputs found
The LISA PathFinder DMU and Radiation Monitor
The LISA PathFinder DMU (Data Management Unit) flight model was formally
accepted by ESA and ASD on 11 February 2010, after all hardware and software
tests had been successfully completed. The diagnostics items are scheduled to
be delivered by the end of 2010. In this paper we review the requirements and
performance of this instrumentation, specially focusing on the Radiation
Monitor and the DMU, as well as the status of their programmed use during
mission operations, on which work is ongoing at the time of writing.Comment: 11 pages, 7 figures, prepared for the Proceedings of the 8th
International LISA Symposium, Classical and Quantum Gravit
Epidemiology of Acromegaly: Review of population studies
Acromegaly is a rare condition necessitating large population studies for the generation of reliable epidemiological data. In this review, we systematically analysed the epidemiological profile of this condition based on recently published population studies from various geographical areas. The total prevalence ranges between 2.8 and 13.7 cases per 100,000 people and the annual incidence rates range between 0.2 and 1.1 cases/100,000 people. The median age at diagnosis is in the fifth decade of life with a median diagnostic delay of 4.5–5 years. Acral enlargement and coarse facial features are the most commonly described clinical manifestations. At the time of detection, most of the tumors are macroadenomas possibly relating to diagnostic delays and posing challenges in the surgical management. Increased awareness of acromegaly amongst the medical community is of major importance aiming to reduce the adverse sequelae of late diagnosis and treatment, improve patient outcomes and, hopefully, reduce the burden on the health care system
Robust synthesis of epoxy resin-filled microcapsules for application to self-healing materials
Mechanically and thermally robust microcapsules containing diglycidyl ether bisphenol A-based epoxy resin and a high-boiling-point organic solvent were synthesized in high yield using in situ polymerization of urea and formaldehyde in an oil-in-water emulsion. Microcapsules were characterized in terms of their size and size distribution, shell surface morphology and thermal resistance to the curing cycles of commercially used epoxy polymers. The size distribution of the capsules and characteristics such as shell thickness can be controlled by the specific parameters of microencapsulation, including concentrations of reagents, stirrer speed and sonication. Selected microcapsules, and separated core and shell materials, were analysed using thermogravimetric analysis and differential scanning calorimetry. It is demonstrated that capsules lose minimal 2.5 wt% at temperatures no higher than 120°C. These microcapsules can be applied to self-healing carbon fibre composite structural materials, with preliminary results showing promising performance
A comparison of match demands using ball-in-play versus whole match data in professional soccer players of the English Championship
This is the first study to report the Whole Match, ball-in-play (BiP), ball-out-of-play (BoP), and Max BiP (worst case scenario phases of play) demands of professional soccer players competing in the English Championship. Effective playing time per soccer game is typically 90 s) providing precise peak match demands. Whole-match demands recorded were compared to BiP and Max BiP, and BiP data excluded data from all match stoppages, providing a more precise analysis of match demands. Whole-match metrics were significantly lower than BiP metrics (p 90 s. No significant differences were found between positions. Ball-in-play analysis allows an accurate representation of the game and physical demands imposed on professional soccer players. Through having a clearer understanding of maximum game demands in professional soccer, will enable practitioners to design highly specific training methods
Sing to me, baby: Infants show neural tracking and rhythmic movements to live and dynamic maternal singing
Infant-directed singing has unique acoustic characteristics that may allow even very young infants to respond to the rhythms carried through the caregiver’s voice. The goal of this study was to examine neural and movement responses to live and dynamic maternal singing in 7-month-old infants and their relation to linguistic development. In total, 60 mother-infant dyads were observed during two singing conditions (playsong and lullaby). In Study 1 (n = 30), we measured infant EEG and used an encoding approach utilizing ridge regressions to measure neural tracking. In Study 2 (n =40), we coded infant rhythmic movements. In both studies, we assessed children’s vocabulary when they were 20 months old. In Study 1, we found above-threshold neural tracking of maternal singing, with superior tracking of lullabies than playsongs. We also found that the acoustic features of infant-directed singing modulated tracking. In Study 2, infants showed more rhythmic movement to playsongs than lullabies. Importantly, neural coordination (Study 1) and rhythmic movement (Study 2) to playsongs were positively related to infants’ expressive vocabulary at 20 months. These results highlight the importance of infants’ brain and movement coordination to their caregiver’s musical presentations, potentially as a function of musical variability
Slip behavior in liquid films on surfaces of patterned wettability: Comparison between continuum and molecular dynamics simulations
We investigate the behavior of the slip length in Newtonian liquids subject
to planar shear bounded by substrates with mixed boundary conditions. The upper
wall, consisting of a homogenous surface of finite or vanishing slip, moves at
a constant speed parallel to a lower stationary wall, whose surface is
patterned with an array of stripes representing alternating regions of no-shear
and finite or no-slip. Velocity fields and effective slip lengths are computed
both from molecular dynamics (MD) simulations and solution of the Stokes
equation for flow configurations either parallel or perpendicular to the
stripes. Excellent agreement between the hydrodynamic and MD results is
obtained when the normalized width of the slip regions, , where is the (fluid) molecular diameter characterizing the
Lennard-Jones interaction. In this regime, the effective slip length increases
monotonically with to a saturation value. For and transverse flow configurations, the non-uniform interaction
potential at the lower wall constitutes a rough surface whose molecular scale
corrugations strongly reduce the effective slip length below the hydrodynamic
results. The translational symmetry for longitudinal flow eliminates the
influence of molecular scale roughness; however, the reduced molecular ordering
above the wetting regions of finite slip for small values of
increases the value of the effective slip length far above the hydrodynamic
predictions. The strong inverse correlation between the effective slip length
and the liquid structure factor representative of the first fluid layer near
the patterned wall illustrates the influence of molecular ordering effects on
slip in non-inertial flows.Comment: 12 pages, 10 figures Web reference added for animations:
http://www.egr.msu.edu/~priezjev/bubble/bubble.htm
Charge Management for Gravitational Wave Observatories using UV LEDs
Accumulation of electrical charge on the end mirrors of gravitational wave
observatories, such as the space-based LISA mission and ground-based LIGO
detectors, can become a source of noise limiting the sensitivity of such
detectors through electronic couplings to nearby surfaces. Torsion balances
provide an ideal means for testing gravitational wave technologies due to their
high sensitivity to small forces. Our torsion pendulum apparatus consists of a
movable Au-coated Cu plate brought near a Au-coated Si plate pendulum suspended
from a non-conducting quartz fiber. A UV LED located near the pendulum
photoejects electrons from the surface, and a UV LED driven electron gun
directs photoelectrons towards the pendulum surface. We have demonstrated both
charging and discharging of the pendulum with equivalent charging rates of
, as well as spectral measurements of the pendulum
charge resulting in a white noise level equivalent to .Comment: 5 pages, submitted to PR
Very preterm infants engage in an intervention to train their control of attention: results from the feasibility study of the Attention Control Training (ACT) randomised trial
Background
Very premature birth (gestational age between 28 and 31 + 6 weeks) is associated with increased risk of cognitive delay and attention deficit disorder, which have been linked to anomalies in the development of executive functions (EFs) and their precursors. In particular, very preterm (VP) infants display anomalies in controlling attention and gathering task-relevant information. Early interventions that support attention control may be pivotal in providing a secure base for VP children’s later attainments. The Attention Control Training (ACT) is a cognitive training intervention that targets infants’ abilities to select visual information according to varying task demands but had not been tested in VP infants. We conducted a feasibility study to test the processes we intend to use in a trial delivering the ACT to VP infants.
Methods and design
We tested recruitment and retention of VP infants and their families in a randomised trial, as well as acceptability and completion of baseline and outcome measures. To evaluate these aims, we used descriptive quantitative statistics and qualitative methods to analyse feedback from infants’ caregivers. We also investigated the quality of eye-tracking data collected and indicators of infants’ engagement in the training, using descriptive statistics.
Results
Twelve VP infants were recruited, and 10 (83%) completed the study. Participants’ parents had high education attainment. The rate of completion of baseline and outcome measures was optimal. VP infants demonstrated engagement in the training, completing on average 84 min of training over three visits, and displaying improved performance during this training. Eye-tracking data quality was moderate, but this did not interfere with infants’ engagement in the training.
Discussion
The results suggest the ACT can be delivered to VP infants. However, challenges remain in recruitment of numerous and diverse samples. We discuss strategies to overcome these challenges informed by results of this study.
Trial registration
Registered Registration ID: NCT03896490. Retrospectively registered at Clinical Trials Protocol Registration and Results System (clinicaltrials.gov)
LISA and LISA PathFinder, the endeavour to detect low frequency GWs
This is a review about LISA and its technology demonstrator, LISA PathFinder.
We first describe the conceptual problems which need to be overcome in order to
set up a working interferometric detector of low frequency Gravitational Waves
(GW), then summarise the solutions to them as currently conceived by the LISA
mission team. This will show that some of these solutions require new
technological abilities which are still under development, and which need
proper test before being fully implemented. LISA PathFinder (LPF) is the the
testbed for such technologies. The final part of the paper will address the
ideas and concepts behind the PathFinder as well as their impact on LISA.Comment: 25 pages, 21 figures, presented at the Spanish Relativity Meeting,
Mallorca September 2006. Will be published in Journal of Physics: Conference
Series, IOP. To be published in Journal of Physics: Conference Series, IO
Zirconium−nitrogen intermolecular frustrated Lewis pairs
A series
of intermolecular transition metal frustrated Lewis pairs (FLPs) based
on zirconocene alkoxide complexes ([Cp2ZrÂ(OMes)]+ 1 or ([Cp*2ZrÂ(OMes)]+ 2) with nitrogen Lewis bases (NEt3, NEtiPr2, pyridine, 2-methylpyridine, 2,6-lutidine) are reported.
The interaction between Zr and N depends on the specific derivatives
used, in general more sterically encumbered pairs leading to a more
frustrated interaction; however, DOSY NMR spectroscopy reveals these
interactions to be dynamic in nature. The pairs undergo typical FLP-type
reactivity with D2, CO2, THF, and PhCCD. The
catalytic dehydrocoupling of Me2NH·BH3 is
also reported. Comparisons can be made with previous work employing
phosphines as Lewis bases suggesting that hard–hard or hard–soft
acid–base considerations are of little importance compared
to the more prominent roles of steric bulk and basicity
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