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Semantic and inferencing abilities in children with communication disorders
Background: Semantic and inferencing abilities have not been fully examined in children with communication difficulties.
Aims: To investigate the inferential and semantic abilities of children with communication difficulties using newly designed tasks.
Methods & Procedures: Children with different types of communication disorder were compared with each other and with three groups of typically developing children: those of the same chronological age and two groups of younger children. In total, 25 children aged 11 years with specific language impairment and 22 children, also 11 years of age, with primary pragmatic difficulties were recruited. Typically developing groups aged 11 (nâ=â35; ageâmatch), and those aged 9 (nâ=â40) and 7 (nâ=â37; language similar) also participated as comparisons.
Outcomes & Results: For Semantic Choices, children with specific language impairment performed significantly more poorly than 9â and 11âyearâolds, whilst the pragmatic difficulties group scored significantly lower than all the typically developing groups. Borderline differences between specific language impairment and pragmatic difficulties groups were found. For inferencing, children with communication impairments performed significantly below the 11âyearâold peers, but not poorer than 9â and 7âyearâolds, suggesting that this skill is in line with language ability. Six children in the pragmatic difficulties group who met diagnosis for autism performed more poorly than the other two clinical groups on both tasks, but not statistically significantly so.
Conclusions: Both tasks were more difficult for those with communication impairments compared with peers. Semantic but not inferencing abilities showed a nonâsignificant trend for differences between the two clinical groups and children with pragmatic difficulties performed more poorly than all typically developing groups. The tasks may relate to each other in varying ways according to type of communication difficulty
Cosmological Constraints on Neutrino Injection
We derive general constraints on the relic abundances of a long-lived
particle which mainly decays into a neutrino (and something else) at
cosmological time scales. Such an exotic particle may show up in various
particle-physics models based on physics beyond the standard model. The
constraints are obtained from big-bang nucleosynthesis, cosmic microwave
background and diffuse neutrino and photon fluxes, depending on the lifetime
and the electromagnetic and hadronic branching ratios.Comment: 33 pages, 23 figure
A New Window on Primordial non-Gaussianity
We know very little about primordial curvature perturbations on scales
smaller than about a Mpc. Measurements of the mu-type distortion of the CMB
spectrum provide the unique opportunity to probe these scales over the
unexplored range from 50 to 10^4 Mpc^-1. This is a very clean probe, in that it
relies only on well-understood linear evolution. We point out that correlations
between mu-distortion and temperature anisotropies can be used to test
Gaussianity at these very small scales. In particular the mu-T cross
correlation is proportional to the very squeezed limit of the primordial
bispectrum and hence measures fNL^loc, while mu-mu is proportional to the
primordial trispectrum and measures tauNL. We present a Fisher matrix forecast
of the observational constraints.Comment: 5 pages, one figure. v2: added clarifying comments and references,
fixed typo
A New Method for ISOCAM Data Reduction - I. Application to the European Large Area ISO Survey Southern Field: Method and Results
We have developed a new data reduction technique for ISOCAM LW data and have
applied it to the European Large Area ISO Survey (ELAIS) LW3 (15 micron)
observations in the southern hemisphere (S1). This method, known as LARI
technique and based on the assumption of the existence of two different time
scales in ISOCAM transients (accounting either for fast or slow detector
response), was particularly designed for the detection of faint sources. In the
ELAIS S1 field we obtained a catalogue of 462 15 micron sources with
signal-to-noise ratio >= 5 and flux densities in the range 0.45 - 150 mJy
(filling the whole flux range between the Deep ISOCAM Surveys and the IRAS
Faint Source Survey). The completeness at different flux levels and the
photometric accuracy of this catalogue have been tested with simulations. Here
we present a detailed description of the method and discuss the results
obtained by its application to the S1 LW3 data.Comment: 20 pages, LaTeX, MNRAS style, 20 postscript figures, full catalogue
not yet available at http://boas5.bo.astro.it/~elais/catalogues/. Accepted
for publication in MNRA
Axillary dissection vs. No axillary dissection in breast cancer patients with positive sentinel lymph node: A single institution experience
Developing a Forensic Continuous Audit Model
Despite increased attention to internal controls and risk assessment, traditional audit approaches do not seem to be highly effective in uncovering the majority of frauds. Less than 20 percent of all occupational frauds are uncovered by auditors. Forensic accounting has recognized the need for automated approaches to fraud analysis yet research has not examined the benefits of forensic continuous auditing as a method to detect and deter corporate fraud. The purpose of this paper is to show how such an approach is possible. A model is presented that supports the acceptance of forensic continuous auditing by auditors and management as an effective tool to support the audit function, meet managementâs regulatory objectives, and to combat fraud. An approach to developing such a system is presented
The double Compton emissivity in a mildly relativistic thermal plasma within the soft photon limit
We provide simple and accurate analytic approximations for the low frequency
double Compton emission coefficient that are applicable in a broad range of
physical situations up to mildly relativistic temperatures. These
approximations may be useful for checking in which circumstances the double
Compton process is important. We perform series expansions of the double
Compton emission integral for low energies of the incident photon and electron
and compare the derived analytic expressions with the results obtained by
numerical integrations of the full double Compton cross section. We explicitly
derived analytic approximations to the low frequency double Compton emission
coefficient for initial monochromatic photons and Wien spectra. We show that
combining the analytic approximations given in this paper, an accuracy of
better than 5% over a very broad range of temperatures and under various
physical conditions can be achieved. The double Compton emissivity strongly
depends on the ratio of the incoming photon and electron energies: for hard
photons and cold electrons the emission is strongly suppressed compared to the
case of similar photon and electron energy, whereas in the opposite situation,
i.e. hot electrons and soft initial photons, the emission is enhanced. For
photons and electrons close to thermodynamic equilibrium the double Compton
emissivity increases less rapidly with temperature than in the Lightman-Thorne
approximation and the corrections exceed ~10% for temperatures above 4 keV.Comment: 12 pages, 8 figures, accepted versio
The Role of the Dust in Primeval Galaxies: A Simple Physical Model for Lyman Break Galaxies and Lyman Alpha Emitters
We explore the onset of star formation in the early Universe, exploiting the
observations of high-redshift Lyman-break galaxies (LBGs) and Lyman alpha
emitters (LAEs), in the framework of the galaxy formation scenario elaborated
by Granato et al. (2004) already successfully tested against the wealth of data
on later evolutionary stages. Complementing the model with a simple, physically
plausible, recipe for the evolution of dust attenuation in metal poor galaxies
we reproduce the luminosity functions (LFs) of LBGs and of LAEs at different
redshifts. This recipe yields a much faster increase with galactic age of
attenuation in more massive galaxies, endowed with higher star formation rates.
These objects have therefore shorter lifetimes in the LAE and LBG phases, and
are more easily detected in the dusty submillimeter bright phase. The short UV
bright lifetimes of massive objects strongly mitigate the effect of the fast
increase of the massive halo density with decreasing redshift, thus accounting
for the weaker evolution of the LBG LF, compared to that of the halo mass
function, and the even weaker evolution between z~6 and z~3 of the LAE LF. LAEs
are on the average expected to be younger, with lower stellar masses, and
associated to less massive halos than LBGs. Finally, we show that the
intergalactic medium can be completely reionized at redshift z~6-7 by massive
stars shining in protogalactic spheroids with halo masses from a few 10^10 to a
few 10^11 M_sun, showing up as faint LBGs with magnitude in the range
-17<M_1350<-20, without resorting to any special stellar initial mass function.Comment: 13 pages, 8 figures, uses REVTeX 4 + emulateapj.cls and apjfonts.sty.
Title changed and text revised following referee's comments. Accepted by Ap
On the radio properties of the highest redshift quasars
We present deep radio observations of the most distant complete quasar sample
drawn from the Sloan Digital Sky Survey. Combining our new data with those from
literature we obtain a sample which is ~100 per cent complete down to S_1.4GHz
= 60 \mu Jy over the redshift range 3.8 < z < 5. The fraction of radio
detections is relatively high (~43 per cent), similar to what observed locally
in bright optical surveys. Even though the combined radio and optical
properties of quasars remain overall unchanged from z ~ 5 to the local
Universe, there is some evidence for a slight over-abundance of radio-loud
sources at the highest redshifts when compared with the lower-z regime.
Exploiting the deep radio VLA observations we present the first attempt to
directly derive the radio luminosity function of bright quasars at z ~ 4. The
unique depth -- both in radio and optical -- allows us to thoroughly explore
the population of optically bright FR~II quasars up to z ~ 5 and opens a window
on the behaviour of the brightest FR~I sources. A close investigation of the
space density of radio loud quasars also suggests a differential evolution,
with the more luminous sources showing a less pronounced cut-off at high z when
compared with the less luminous ones.Comment: Accepted for publication in MNRAS, 8 pages, 6 figure
Vascular endothelial growth factor C disrupts the endothelial lymphatic barrier to promote colorectal cancer invasion
Background & Aims
Colorectal cancer (CRC) is highly metastatic. Metastases spread directly into local tissue or invade distant organs via blood and lymphatic vessels, but the role of lymphangiogenesis in CRC progression has not been determined. Lymphangiogenesis is induced via vascular endothelial growth factor C (VEGFC) activation of its receptor, VEGFR3; high levels of VEGFC have been measured in colorectal tumors undergoing lymphangiogenesis, and correlated with metastasis. We investigated VEGFC signaling and lymphatic barriers in human tumor tissues and mice with orthotopic colorectal tumors.
Methods
We performed immunohistochemical, immunoblot, and real-time PCR analyses of colorectal tumor specimens collected from patients; healthy intestinal tissues collected during surgeries of patients without CRC were used as controls. CT26 CRC cells were injected into the distal posterior rectum of BALB/c-nude mice. Mice were given injections of an antibody against VEGFR3 or an adenovirus encoding human VEGFC before orthotopic tumors and metastases formed. Lymph node, lung, and liver tissues were collected and evaluated by flow cytometry. We measured expression of vascular endothelial cadherin (CDH5) on lymphatic vessels in mice and in human intestinal lymphatic endothelial cells.
Results
Levels of podoplanin (a marker of lymphatic vessels), VEGFC, and VEGFR3 were increased in colorectal tumor tissues, compared with controls. Mice that expressed VEGFC from the adenoviral vector had increased lymphatic vessel density and more metastases in lymph nodes, lungs, and livers, compared with control mice. Anti-VEGR3 antibody reduced numbers of lymphatic vessels in colons and prevented metastasis. Expression of VEGFC compromised the lymphatic endothelial barrier in mice and endothelial cells, reducing expression of CDH5, increasing permeability, and increasing trans-endothelial migration by CRC cells. Opposite effects were observed in mice and cells when VEGFR3 was blocked.
Conclusions
VEGFC signaling via VEGFR3 promotes lymphangiogenesis and metastasis by orthotopic colorectal tumors in mice and reduces lymphatic endothelial barrier integrity. Levels of VEGFC and markers of lymphatic vessels are increased in CRC tissues from patients, compared with healthy intestine. Strategies to block VEGFR3 might be developed to prevent CRC metastasis in patients
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