5,903 research outputs found
Talking With Your Children: Activities For Parents to Help Nursery Children's Speaking and Listening Skills
Dewetting of Glassy Polymer Films
Dynamics and morphology of hole growth in a film of power hardening
viscoplastic solid (yield stress ~ [strain-rate]^n) is investigated. At
short-times the growth is exponential and depends on the initial hole size. At
long-times, for n > 1/3, the growth is exponential with a different exponent.
However, for n < 1/3, the hole growth slows; the hole radius approaches an
asymptotic value as time tends to infinity. The rim shape is highly asymmetric,
the height of which has a power law dependence on the hole radius (exponent
close to unity for 0.25 < n < 0.4). The above results explain recent intriguing
experiments of Reiter, Phys. Rev. Lett, 87, 186101 (2001).Comment: 4 pages, 5 figures, RevTe
An evaluation of the impact of a multidisciplinary team, in a single centre, on treatment and survival in patients with inoperable non-small-cell lung cancer
Treatment and survival of patients with inoperable Non-small-cell lung cancer in 1997 (n=117) and 2001 (n=126), before and after the introduction of a multidisciplinary team, was examined in a single centre. There were no differences in age, sex and extent of deprivation between the two years. However, in 2001, 23% of patients received chemotherapy treatment compared with 7% in 1997 (P<0.001). Median survival in 2001 was 6.6 months compared with 3.2 months in 1997 (P<0.001)
Slow dynamics near glass transitions in thin polymer films
The -process (segmental motion) of thin polystyrene films supported
on glass substrate has been investigated in a wider frequency range from
10 Hz to 10 Hz using dielectric relaxation spectroscopy and thermal
expansion spectroscopy. The relaxation rate of the -process increases
with decreasing film thickness at a given temperature above the glass
transition. This increase in the relaxation rate with decreasing film thickness
is much more enhanced near the glass transition temperature. The glass
transition temperature determined as the temperature at which the relaxation
time of the -process becomes a macroscopic time scale shows a distinct
molecular weight dependence. It is also found that the Vogel temperature has
the thickness dependence, i.e., the Vogel temperature decreases with decreasing
film thickness. The expansion coefficient of the free volume is
extracted from the temperature dependence of the relaxation time within the
free volume theory. The fragility index is also evaluated as a function of
thickness. Both and are found to decrease with decreasing film
thickness.Comment: 9 pages, 7 figures, and 2 table
Comment on ‘Tumour-infiltrating inflammation and prognosis in colorectal cancer: systematic review and meta-analysis’
No abstract available
Performance of networks of artificial neurons: The role of clustering
The performance of the Hopfield neural network model is numerically studied
on various complex networks, such as the Watts-Strogatz network, the
Barab{\'a}si-Albert network, and the neuronal network of the C. elegans.
Through the use of a systematic way of controlling the clustering coefficient,
with the degree of each neuron kept unchanged, we find that the networks with
the lower clustering exhibit much better performance. The results are discussed
in the practical viewpoint of application, and the biological implications are
also suggested.Comment: 4 pages, to appear in PRE as Rapid Com
True blue: Temporal and spatial stability of pelagic wildlife at a submarine canyon
Funding: This research was funded through the Ian Potter Foundation and the First author.In coastal systems, marine-protected areas (MPAs) have been shown to increase the diversity, abundance, and biomass of wildlife assemblages as well as their resilience to climate change. The effectiveness of pelagic MPAs is less clear, with arguments against their establishment typically based on the highly mobile nature of pelagic taxa. We used mid-water stereo-baited remote underwater video systems (stereo-BRUVS) and spatial predictive models to characterize the pelagic wildlife assemblage at the head of the Perth Canyon, one of the largest submarine canyons in Australia, over a 7-yr period (2013–2019). The total number of unique taxa and mean values of taxonomic richness, abundance, fork length, and biomass demonstrated strong interannual stability, although mean taxonomic richness and abundance were significantly lower in 2018 relative to other years. Seasonal variability was absent in 2016, but in 2018, taxonomic richness and abundance were three times greater in the Austral spring than in the autumn. Some mobile megafauna were only recorded at the Perth Canyon Marine Park (PCMP) in the autumn, suggesting a seasonal component to their occurrence. The fine-scale distribution of pelagic taxa at the canyon head was largely stable over time, with many areas of higher relative probability of presence located outside protected zones. Despite a degree of variability that may relate to the effect of the El Niño Southern Oscillation on the Leeuwin Current, the PCMP assemblage demonstrates a relatively high degree of spatiotemporal stability. Stronger protection of the PCMP (IUCN II or higher) would potentially improve conservation outcomes for many species of pelagic wildlife.Publisher PDFPeer reviewe
PAH emission from Herbig AeBe stars
We present spectra of a sample of Herbig Ae and Be (HAeBe) stars obtained
with the Infrared Spectrograph on the Spitzer Space Telescope. All but one of
the Herbig stars show emission from polycyclic aromatic hydrocarbons (PAHs) and
seven of the spectra show PAH emission, but no silicate emission at 10 microns.
The central wavelengths of the 6.2, 7.7--8.2, and 11.3 micron emission features
decrease with stellar temperature, indicating that the PAHs are less
photo-processed in cooler radiation fields. The apparent low level of photo
processing in HAeBe stars, relative to other PAH emission sources, implies that
the PAHs are newly exposed to the UV-optical radiation fields from their host
stars. HAeBe stars show a variety of PAH emission intensities and ionization
fractions, but a narrow range of PAH spectral classifications based on
positions of major PAH feature centers. This may indicate that, regardless of
their locations relative to the stars, the PAH molecules are altered by the
same physical processes in the proto-planetary disks of intermediate-mass
stars. Analysis of the mid-IR spectral energy distributions indicates that our
sample likely includes both radially flared and more flattened/settled disk
systems, but we do not see the expected correlation of overall PAH emission
with disk geometry. We suggest that the strength of PAH emission from HAeBe
stars may depend not only on the degree of radial flaring, but also on the
abundance of PAHs in illuminated regions of the disks and possibly on the
vertical structure of the inner disk as well.Comment: 52 pages, 12 figure
Probing the cosmic star formation using long Gamma-Ray Bursts: New constraints from the Spitzer Space Telescope
We report on IRAC-4.5mic, IRAC-8.0mic and MIPS-24mic deep observations of 16
Gamma-Ray Burst (GRBs) host galaxies performed with the Spitzer Space
Telescope, and we investigate in the thermal infrared the presence of evolved
stellar populations and dust-enshrouded star-forming activity associated with
these objects. Our sample is derived from GRBs that were identified with
sub-arcsec localization between 1997 and 2001, and only a very small fraction
(~20%) of the targeted sources is detected down to f_4.5mic ~3.5microJy and
f_24mic ~85microJy (3sigma). This likely argues against a population dominated
by massive and strongly-starbursting (i.e., SFR > ~100 Msol/yr) galaxies as it
has been recently suggested from submillimeter/radio and optical studies of
similarly-selected GRB hosts. Furthermore we find evidence that some GRBs do
not occur in the most infrared-luminous regions -- hence the most actively
star-forming environments -- of their host galaxies. Should the GRB hosts be
representative of all star-forming galaxies at high redshift, models of
infrared galaxy evolution indicate that > ~50% of GRB hosts should have f_24mic
> ~100microJy. Unless the identification of GRBs prior to 2001 was prone to
strong selection effects biasing our sample against dusty galaxies, we infer in
this context that the GRBs identified with the current techniques can not be
directly used as unbiased probes of the global and integrated star formation
history of the Universe.Comment: ApJ in press, 23 pages, 8 figures (scheduled for the ApJ 10 May 2006,
v642 2 issue). Full resolution available at
http://perceval.as.arizona.edu/~elefloch/Publis/ms_grb_spitzer.pd
From vocational training to education: the development of a no-frontiers education policy for Europe?
This article focuses on developments towards an EU educational policy. Education was not included as one of the Community competencies in the Treaty of Rome. The first half of the article analyses the way that the European Court of Justice and the Commission of the European Communities between them managed to develop a series of substantial Community programmes out of Article 128 on vocational training. The second half of the article discusses educational developments in the community following the Treaty on European Union and the Treaty of Amsterdam. Whilst the legal competence of the community now includes education, the author's argument is that the inclusion of an educational competence will not result in further developments to mirror those in the years before the Treaty on Europe</p
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