1,998 research outputs found
Long-term survival for a cohort of adults with cerebral palsy
The aim of this study was to investigate long-term survival and examine causes of death in adult patients with cerebral palsy (CP). A 1940–1950 birth cohort based on paediatric case referral allows for long-term survival follow-up. Survival is analyzed by birth characteristics and severity of disability from age 20 years (and age 2y for a subset of the data). Survival outcome compared with that expected in the general population based on English life tables. The main cohort consisted of 341 individuals, with 193 males and 148 females. Conditional on surviving to age 20 years, almost 85% of the cohort survived to age 50 years (a comparable estimate for the general population is 96%). Very few deaths were attributed to CP for those people dying over 20 years of age. Females survived better than males. However, females faced a greater increase in risk relative to the general population than did males. We conclude that survival outlook is good though lower than in the general population. The relative risk of death compared with the UK population decreases with age, although it shows some indication of rising again after age 50 years. Many more deaths were caused by diseases of the respiratory system among those dying in their 20s and 30s than would be expected in the general population. Many fewer deaths than expected in this age group are caused by injuries and accidents. For those people who die in their 40s and 50s, an increase in deaths due to diseases of the circulatory system and neoplasms is observed. More deaths than expected in this age group are due to diseases of the nervous system
On the extended two-parameter generalized skew-normal distribution
We propose a three-parameter skew-normal distribution, obtained by using hidden truncation on a skew-normal random variable. The hidden truncation framework permits direct interpretation of the model parameters. A link is established between the model and the closed skew-normal distribution
A Sample Selection Model with Skew-normal Distribution
Non-random sampling is a source of bias in empirical research. It is common for the outcomes of interest (e.g. wage distribution) to be skewed in the source population. Sometimes, the outcomes are further subjected to sample selection, which is a type of missing data, resulting in partial observability. Thus, methods based on complete cases for skew data are inadequate for the analysis of such data and a general sample selection model is required. Heckman proposed a full maximum likelihood estimation method under the normality assumption for sample selection problems, and parametric and non-parametric extensions have been proposed. We generalize Heckman selection model to allow for underlying skew-normal distributions. Finite-sample performance of the maximum likelihood estimator of the model is studied via simulation. Applications illustrate the strength of the model in capturing spurious skewness in bounded scores, and in modelling data where logarithm transformation could not mitigate the effect of inherent skewness in the outcome variable
Water quality in the Wingecarribee Shire, NSW
This paper reports on a water quality monitoring program carried out for Wingecarribee Shire Council between March 2002 and July 2004 by University of Wollongong staff and students. Initially 40 sites were sampled on four occasions over three months in a pilot program leading to the selection of sites and parameters for a two year program of monthly monitoring. A range of chemical, physical and biological parameters was measured including nutrients and faecal coliform bacteria on samples collected over the 26 approximately monthly sampling trips. Chlorophyll a, phaeophyton and blue-green algae were also determined over a shorter period. The sampling period included the particularly hot and dry spell September 2002 - January 2003 and a return to less extreme conditions after February 2003. The range of nutrient and coliform data is reported with discussion of the effects of rainfall patterns on nutrients and on faecal coliform counts at the various sites. Small creek sites showed significant changes to nutrient regimes in the long dry spell, whereas the same effect was not apparent in larger river sites. Very wide ranges of faecal coliform counts were found, especially at small creek sites in farmland. Excepting extreme results, generally elevated coliform counts were found when rainfall occurred 0-3 days immediately prior to sampling. Generally lower counts were found in drier weather. The Shire has already implemented some measures to improve water quality in response to this program
Enhancing the Transdermal Delivery of ‘Next Generation’ Variable New Antigen Receptors Using Microarray Patch Technology: a Proof-of-Concept Study
Heavy chain only binding proteins, such as variable new antigen receptors (VNARs), have emerged as an alternative to the highly successful therapeutic monoclonal antibodies (mAb). Owing to their small size (» 11 kDa)and single chain only architecture, they are amenable to modular reformatting and can be produced using inexpensive expression systems. Furthermore, due to their low molecular weight (MW) and high stability, theymay be suitable for alternative delivery strategies, such as microarray array patches (MAPs). In this study, thetransdermal delivery of ELN22-104, a multivalent anti-hTNF-a VNAR, was examined using both dissolving andhydrogel-forming MAPs. For dissolving MAPs, the cumulative in vitro permeation of ELN22-104 reached a plateau after 2 h (12.24 § 0.17 mg). This could be important for bolus dosing. Assessing two hydrogel-formingMAPs in vitro, PVP/PVA hydrogel-forming MAPs delivered significantly higher drug doses when compared to‘super swelling’ MAPs, equivalent to 43.13 § 10.36 mg and 23.13 § 5.66 mg, respectively (p < 0.05). Consequently, this study has proven that by modifying the MAP system, the transdermal delivery of a VNAR acrossthe skin can be enhanced. Furthermore, this proof-of-concept study has shown that transdermal delivery of‘next generation’ biotherapeutics is achievable using MAP technology
The first confirmation of V-type asteroids among the Mars crosser population
The Mars crossing region constitutes a path to deliver asteroids from the
Inner Main Belt to the Earth crossing space. While both the Inner Main Belt and
the population of Earth crossing asteroids contains a significant fraction of
asteroids belonging to the V taxonomic class, only two of such V-type asteroids
has been detected in the Mars crossing region up to now. In this work, we
searched for asteroids belonging to the V class among the population of Mars
crossing asteroids, in order to support alternative paths to the delivery of
this bodies into the Earth crossing region. We selected 18 candidate V-type
asteroids in the Mars crossing region using observations contained in the Sloan
Digital Sky Survey Moving Objects Catalog. Then, we observed 4 of these
candidates to take their visible spectra using the Southern Astrophysical
Research Telescope (SOAR). We also performed the numerical simulation of the
orbital evolution of the observed asteroids. We confirmed that 3 of the
observed asteroids belong to the V class, and one of these may follow a path
that drives it to an Earth collision in some tens of million years
Dendritic cell reconstitution is associated with relapse-free survival and acute GVHD severity in children after allogeneic stem cell transplantation
DCs are potent APCs and key regulators of innate and adaptive immunity. After allo-SCT, their reconstitution in the peripheral blood (PB) to levels similar to those in healthy individuals tends to be slow. We investigate the age- and sex-dependant immune reconstitution of myeloid (mDC) and plasmacytoid DC (pDC) in the PB of 45 children with leukaemia or myelodysplastic syndrome (aged 1-17 years, median 10) after allo-SCT with regard to relapse, acute GVHD (aGVHD) and relapse-free survival. Low pDC/μL PB up to day 60 post SCT are associated with higher incidence of moderate or severe aGVHD (P=0.035), whereas high pDC/μL PB up to day 60 are associated with higher risk of relapse (P<0.001). The time-trend of DCs/μL PB for days 0-200 is a significant predictor of relapse-free survival for both mDCs (P<0.001) and pDCs (P=0.020). Jointly modelling DC reconstitution and complications improves on these simple criteria. Compared with BM, PBSC transplants tend to show slower mDC/pDC reconstitution (P=0.001, 0.031, respectively), but have no direct effect on relapse-free survival. These results suggest an important role for both mDCs and pDCs in the reconstituting immune system. The inclusion of mDCs and pDCs may improve existing models for complication prediction following allo-SCT
Taxonomy of asteroid families among the Jupiter Trojans: Comparison between spectroscopic data and the Sloan Digital Sky Survey colors
We present a comparative analysis of the spectral slope and color
distributions of Jupiter Trojans, with particular attention to asteroid
families. We use a sample of data from the Moving Object Catalogue of the Sloan
Digital Sky Survey, together with spectra obtained from several surveys. A
first sample of 349 observations, corresponding to 250 Trojan asteroids, were
extracted from the Sloan Digital Sky Survey, and we also extracted from the
literature a second sample of 91 spectra, corresponding to 71 Trojans. The
spectral slopes were computed by means of a least-squares fit to a straight
line of the fluxes obtained from the Sloan observations in the first sample,
and of the rebinned spectra in the second sample. In both cases the reflectance
fluxes/spectra were renormalized to 1 at 6230 . We found that the
distribution of spectral slopes among Trojan asteroids shows a bimodality.
About 2/3 of the objects have reddish slopes compatible with D-type asteroids,
while the remaining bodies show less reddish colors compatible with the P-type
and C-type classifications. The members of asteroid families also show a
bimodal distribution with a very slight predominance of D-type asteroids, but
the background is clearly dominated by the D-types. The L4 and L5 swarms show
different distributions of spectral slopes, and bimodality is only observed in
L4. These differences can be attributed to the asteroid families since the
backgraound asteroids show the same slope distribtuions in both swarms. The
analysis of individual families indicates that the families in L5 are
taxonomically homogeneous, but in L4 they show a mixture of taxonomic types. We
discuss a few scenarios that might help to interpret these results.Comment: 20 pages, 15 figures, 2 table
Density variation during respiration affects PET quantitation in the lung
PET quantitation depends on the accuracy of the CT-derived attenuation correction map. In the lung, respiration leads to both positional and density mismatches, causing PET quantitation errors at lung borders but also within the whole lung. The aim of this work is to determine the extent of the associated errors on the measured time activity curves (TACs) and the corresponding kinetic parameter estimates. 5 patients with idiopathic pulmonary fibrosis underwent dynamic 18 F-FDG PET and cine-CT imaging as part of an ongoing study. The cine-CT was amplitude gated using PCA techniques to produce end expiration (EXP), end inspiration (INS) and mid-breathing cycle (MID) gates representative of a short clinical CT acquisition. The ungated PET data were reconstructed with each CT gate and the TACs and kinetic parameters compared. Patient representative XCAT simulations with varying lung density, both with and without motion, were also produced to represent the above study allowing comparison of true to measured results. In all cases, the obtained PET TACs differed with each CT gate. For ROIs internal to the lung, the effect was dominated by changes in density, as opposed to motion. The errors in the TACs varied with time, providing evidence that errors due to attenuation mismatch depend on activity distribution. In the simulations, some kinetic parameters were over- and under-estimated by a factor of 2 in the INS and EXP gates respectively. For the patients, the maximum variation in kinetic parameters was 20%. Our results show that whole lung density changes during the respiratory cycle have a significant impact on PET quantitation. This is especially true of the kinetic parameter estimates as the extent of the error is dependent on tracer distribution which varies with time. It is therefore vital to use matched PET/CT for attenuation correction
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