22,242 research outputs found
Early life growth patterns persist for 12 years and impact pulmonary outcomes in cystic fibrosis
BACKGROUND:
In children with cystic fibrosis (CF), recovery from growth faltering within 2 years of diagnosis (Responders) is associated with better growth and less lung disease at age 6 years. This study examined whether these benefits are sustained through 12 years of age.
METHODS:
Longitudinal growth from 76 children with CF enrolled in the Wisconsin CF Neonatal Screening Project was examined and categorized into 5 groups: R12, R6, and R2, representing Responders who maintained growth improvement to age 12, 6, and 2 years, respectively, and I6 and N6, representing Non-responders whose growth did and did not improve during ages 2-6 years, respectively. Lung disease was evaluated by % predicted forced expiratory volume in one second (FEV1) and chest radiograph (CXR) scores.
RESULTS:
Sixty-two percent were Responders. Within this group, 47% were R12, 28% were R6, and 25% were R2. Among Non-responders, 76% were N6. CF children with meconium ileus (MI) had worse lung function and CXR scores compared to other CF children. Among 53 children with pancreatic insufficiency without MI, R12 had significantly better FEV1 (97-99% predicted) and CXR scores during ages 6-12 years than N6 (89-93% predicted). Both R6 and R2 experienced a decline in FEV1 by ages 10-12 years.
CONCLUSIONS:
Early growth recovery in CF is critical, as malnutrition during infancy tends to persist and catch-up growth after age 2 years is difficult. The longer adequate growth was maintained after early growth recovery, the better the pulmonary outcomes at age 12 years
Elastic metamaterials with simultaneously negative effective shear modulus and mass density
We propose a type of elastic metamaterial comprising fluid-solid composite
inclusions which can possess negative shear modulus and negative mass density
over a large frequency region. Such a solid metamaterial has a unique elastic
property that only transverse waves can propagate with a negative dispersion
while longitudinal waves are forbidden. This leads to many interesting
phenomena such as negative refraction, which is demonstrated by using a wedge
sample, and a significant amount of mode conversion from transverse waves to
longitudinal waves that cannot occur on the interface of two natural solids
Effects of spatial elements and sound sources on sound field in Main Hall of Chinese Buddhist temple
In Chinese Han Buddhist temples, the Main Hall is the paramount indoor religious location, for which acoustic quality is very important for several Buddhist rites held within; however, the sound field in the Main Hall has not yet been analyzed scientifically. By combining sound field measurement with acoustic simulation, this study investigated the effects of spatial elements and sound source characteristics in a Main Hall, revealing that both fabric sound absorbers and Buddha statues mounted within had a pronounced effect on the sound field. Using an acoustic model of the Main Hall of the Xiantong Temple as an example, when various fabric sound absorbers were removed, the mid-frequency reverberation time (T30m) and mid-frequency early decay time (EDTm) increased by 32.3% and 46.8%, respectively. When fabric sound absorbers and Buddha statues were removed, the sound pressure level was not significantly affected. The form of the roof did not significantly impact the indoor sound field. The directivity of the sound sources did not significantly affect the T30m but did affect the EDTm and the speech transmission index (STI). When monks chanted sutras face-to-face, the STI was maximized. Additionally, changing the positions of sound sources moderately affected the EDT and STI
Interrelation between radio and X-ray signatures of drifting subpulses in pulsars
We examined a model of partially screened gap region above the polar cap, in
which the electron-positron plasma generated by sparking discharges coexists
with thermionic flow ejected by the bombardment of the surface beneath these
sparks. Our special interest was the polar cap heating rate and the subpulse
drifting rate, both phenomena presumably associated with sparks operating at
the polar cap. We investigated correlation between the intrinsic drift rate and
polar cap heating rate and found that they are coupled to each other in such a
way that the thermal X-ray luminosity from heated polar cap depends only
on the observational tertiary subpulse drift periodicity (polar cap
carousel time). Within our model of partially screened gap we derived the
simple formula relating and , and showed that it holds for
PSRs B094310 and B1133+16, which are the only two pulsars in which both
and are presently known.Comment: 4 page
Wave Excitation in Disks Around Rotating Magnetic Stars
The accretion disk around a rotating magnetic star (neutron star, white dwarf
or T Tauri star) is subjected to periodic vertical magnetic forces from the
star, with the forcing frequency equal to the stellar spin frequency or twice
the spin frequency. This gives rise bending waves in the disk that may
influence the variabilities of the system. We study the excitation, propagation
and dissipation of these waves using a hydrodynamical model coupled with a
generic model description of the magnetic forces. The bending waves are
excited at the Lindblad/vertical resonance, and propagate either to larger
radii or inward toward the corotation resonance where dissipation takes place.
While the resonant torque is negligible compared to the accretion torque, the
wave nevertheless may reach appreciable amplitude and can cause or modulate
flux variabilities from the system. We discuss applications of our result to
the observed quasi-periodic oscillations from various systems, in particular
neutron star low-mass X-ray binaries.Comment: Small changes/clarifications. To be published in ApJ, Aug.20,2008
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You are how you travel: A multi-task learning framework for Geodemographic inference using transit smart card data
Geodemographics, providing the information of population's characteristics in the regions on a geographical basis, is of immense importance in urban studies, public policy-making, social research and business, among others. Such data, however, are difficult to collect from the public, which is usually done via census, with a low update frequency. In urban areas, with the increasing prevalence of public transit equipped with automated fare payment systems, researchers can collect massive transit smart card (SC) data from a large population. The SC data record human daily activities at an individual level with high spatial and temporal resolutions. It can reveal frequent activity areas (e.g., residential areas) and travel behaviours of passengers that are intimately intertwined with personal interests and characteristics. This provides new opportunities for geodemographic study. This paper seeks to develop a framework to infer travellers' demographics (such as age, income level and car ownership, et al.) and their residential areas for geodemographic mapping using SC data with a household survey. We first use a decision tree diagram to detect passengers' residential areas. We then represent each individual's spatio-temporal activity pattern derived from multi-week SC data as a 2D image. Leveraging this representation, a multi-task convolutional neural network (CNN) is employed to predict multiple demographics of individuals from the images. Combing the demographics and locations of their residence, geodemographic information is further obtained. The methodology is applied to a large-scale SC dataset provided by Transport for London. Results provide new insights in understanding the relationship between human activity patterns and demographics. To the best of our knowledge, this is the first attempt to infer geodemographics by using the SC data
On the blow-up phenomenon for a generalized Davey-Stewartson system
The blow-up solutions of the Cauchy problem for a generalized Davey–Stewartson system, which models the wave propagation in a bulk medium made of an elastic material with coupled stresses, are investigated. The mass concentration is established for all the blow-up solutions of the system. The profile of the minimal blow-up solutions as t → T (blow-up time) is discussed in detail in terms of the ground state
An Exact No Free Lunch Theorem for Community Detection
A precondition for a No Free Lunch theorem is evaluation with a loss function
which does not assume a priori superiority of some outputs over others. A
previous result for community detection by Peel et al. (2017) relies on a
mismatch between the loss function and the problem domain. The loss function
computes an expectation over only a subset of the universe of possible outputs;
thus, it is only asymptotically appropriate with respect to the problem size.
By using the correct random model for the problem domain, we provide a
stronger, exact No Free Lunch theorem for community detection. The claim
generalizes to other set-partitioning tasks including core/periphery
separation, -clustering, and graph partitioning. Finally, we review the
literature of proposed evaluation functions and identify functions which
(perhaps with slight modifications) are compatible with an exact No Free Lunch
theorem
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