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 (n = 35; age‐match), and those aged 9 (n = 40) and 7 (n = 37; language similar) also participated as comparisons. Outcomes & Results: For Semantic Choices, children with specific language impairment performed significantly more poorly than 9‐ and 11‐year‐olds, 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 11‐year‐old peers, but not poorer than 9‐ and 7‐year‐olds, 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 non‐significant 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

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 management’s 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