206 research outputs found
Practical implications of GPR investigation using 3D data reconstruction and transmission tomography
Non-destructive investigation using ground penetrating radar is becoming
more popular in the inspection of civil structures. Currently, traditional 2D
imaging is used as a preliminary tool to fi nd possible areas of interest for
more detailed inspection, which can be accomplished by more advanced
techniques like 3D image reconstruction or tomography. In this paper,
a general overview of the work done at University of Minho regarding these
techniques is presented, together with their limitations and advantages over
typical radargrams, with implications for civil engineering applications. For
this purpose, data acquisition on two large masonry walls and one large
concrete specimen have been carried out, using refl ection mode, 3D
reconstruction and transmission tomography. The specimens have been
specially built for non-destructive inspection techniques testing, incorporating
different materials and internal voids. Radar tomography and 3D image
reconstruction techniques provided much more detailed information about
structural integrity and shapes and location of the voids, when compared to
2D imaging originally used for potential target identification.Fundação para a Ciência e a Tecnologia (FCT) - POCTI SFRH/BD/6409/2001"Sustainable Bridges" European project - FP6-PLT-0165
Final State Interaction Effects in pol 3He(pol e,e'p)
Asymmetries in quasi-elastic pol 3He(pol e,e'p) have been measured at a
momentum transfer of 0.67 (GeV/c)^2 and are compared to a calculation which
takes into account relativistic kinematics in the final state and a
relativistic one-body current operator. With an exact solution of the Faddeev
equation for the 3He-ground state and an approximate treatment of final state
interactions in the continuum good agreement is found with the experimental
data.Comment: 11 pages, 6 figures, submitted to Phys. Lett. B, revised version,
sensitivity study to relativity and NN-potential adde
Hard Two-Photon Contribution to Elastic Lepton-Proton Scattering: Determined by the OLYMPUS Experiment
The OLYMPUS collaboration reports on a precision measurement of the
positron-proton to electron-proton elastic cross section ratio, ,
a direct measure of the contribution of hard two-photon exchange to the elastic
cross section. In the OLYMPUS measurement, 2.01~GeV electron and positron beams
were directed through a hydrogen gas target internal to the DORIS storage ring
at DESY. A toroidal magnetic spectrometer instrumented with drift chambers and
time-of-flight scintillators detected elastically scattered leptons in
coincidence with recoiling protons over a scattering angle range of to . The relative luminosity between the two beam species
was monitored using tracking telescopes of interleaved GEM and MWPC detectors
at , as well as symmetric M{\o}ller/Bhabha calorimeters at
. A total integrated luminosity of 4.5~fb was collected. In
the extraction of , radiative effects were taken into account
using a Monte Carlo generator to simulate the convolutions of internal
bremsstrahlung with experiment-specific conditions such as detector acceptance
and reconstruction efficiency. The resulting values of , presented
here for a wide range of virtual photon polarization ,
are smaller than some hadronic two-photon exchange calculations predict, but
are in reasonable agreement with a subtracted dispersion model and a
phenomenological fit to the form factor data.Comment: 5 pages, 3 figures, 2 table
Current challenges in software solutions for mass spectrometry-based quantitative proteomics
This work was in part supported by the PRIME-XS project, grant agreement number 262067, funded by the European Union seventh Framework Programme; The Netherlands Proteomics Centre, embedded in The Netherlands Genomics Initiative; The Netherlands Bioinformatics Centre; and the Centre for Biomedical Genetics (to S.C., B.B. and A.J.R.H); by NIH grants NCRR RR001614 and RR019934 (to the UCSF Mass Spectrometry Facility, director: A.L. Burlingame, P.B.); and by grants from the MRC, CR-UK, BBSRC and Barts and the London Charity (to P.C.
Socio-economic inequalities in physical activity practice among Italian children and adolescents: a cross-sectional study
Aim: The aim of the study was to evaluate whether socio-economic inequalities in the practice of physical activity existed among children and adolescents, using different indicators of socio-economic status (SES). Subjects and methods: Data were derived from the Italian National Health Interview Survey carried out in 2004–2005, which examined a large random sample of the Italian population using both an interviewer-administered and a self-compiled questionnaire. This study was based on a sample of 15,216 individuals aged 6–17 years. The practice of physical activity was measured on the basis of questions regarding frequency and intensity of activity during leisure time over the past 12 months. Parents’ educational and occupational level, as well as family’s availability of material resource, were used as indicators of SES. Multivariable logistic regression analyses were performed to estimate the contribution of each SES indicator to the practice of physical activity, adjusting for potential confounding factors. The results of the regression models are expressed as odds ratio (OR) with 95% confidence intervals (95% CI). Results: About 64% of children and adolescents in the sample declared that they participated in moderate or vigorous physical activity at least once a week. After adjustment for gender, age, parental attitudes towards physical activity and geographical area, the practice of physical activity increased with higher parental educational and occupational level and greater availability of material resources. Children and adolescents whose parents held a middle or high educational title were 80% more likely to practice moderate or vigorous physical activity than subjects whose parents had a lower level of education (OR = 1.80, 95% CI: 1.40–2.33), while subjects with unemployed parents had an odds of practicing moderate or vigorous physical activity 0.43 times that of those children whose parents belonged to the top job occupation category (administrative/professionals). Socio-economic differences were about the same when the practice of vigorous physical activity only was considered instead of that of moderate or vigorous physical activity. Conclusion: Interventions that promote the practice of physical activity, and especially those aimed at the wider physical and social environment, are strongly needed to contrast socio-economic differences in physical activity among children and adolescents
Multidimensional treatment foster care for preschoolers: early findings of an implementation in the Netherlands
Multidimensional Treatment Foster Care (MTFC) has been shown to be an evidence based alternative to residential rearing and an effective method to improve behavior and attachment of preschool foster children in the US. This preliminary study investigated an application of MTFC for preschoolers (MTFC-P) in the Netherlands focusing on behavioral outcomes in course of the intervention. To examine the following hypothesis: “the time in the MTFC-P intervention predicts a decline in problem behavior, as this is the desired outcome for children assigned to MTFC-P”, we assessed the daily occurrence of 38 problem behaviors via telephone interviews. Repeated measures revealed significant reduced problem behavior in course of the program. MTFC-P promises to be a treatment model suitable for high-risk foster children, that is transferable across centres and countries
The neutron charge form factor and target analyzing powers from 3He(e, e\u27n) scattering
The charge form factor of the neutron has been determined from asymmetries measured in quasi-elastic 3He(e, e\u27n) at a momentum transfer of 0.67 (GeV/c)2. In addition, the target analyzing power, Ayo, has been measured to study effects of final state interactions and meson exchange currents
The mode of school transportation in pre-pubertal children does not influence the accrual of bone mineral or the gain in bone size - two year prospective data from the paediatric osteoporosis preventive (POP) study
<p>Abstract</p> <p>Background</p> <p>Walking and cycling to school are one source of regular physical activity. The aim of this two years observational study in pre-pubertal children was to evaluate if walking and cycling to school was associated with higher total amount of physical activity and larger gain in bone mineral content (BMC) and bone width than when going by car or bus.</p> <p>Methods</p> <p>133 boys and 99 girls aged 7-9 years were recruited to the Malmö Prospective Paediatric Osteoporosis Prevention (POP) study. BMC (g) was measured by dual X-ray absorptiometry (DXA) in total body, lumbar spine (L2-L4) and femoral neck (FN) at baseline and after 24 months. Bone width was measured in L2-L4 and FN. Skeletal changes in the 57 boys and 48 girls who consistently walked or cycled to school were compared with the 24 boys and 17 girls who consistently went by bus or car. All children remained in Tanner stage I. Level of everyday physical activity was estimated by accelerometers worn for four consecutive days and questionnaires. Comparisons were made by independent student's t-tests between means and Fisher's exact tests. Analysis of covariance (ANCOVA) was used to adjust for group differences in age at baseline, duration of organized physical activity, annual changes in length and BMC or bone width if there were differences in these traits at baseline.</p> <p>Results</p> <p>After the adjustments, there were no differences in the annual changes in BMC or bone width when comparing girls or boys who walked or cycled to school with those who went by car or bus. Furthermore, there were no differences in the levels of everyday physical activity objectively measured by accelerometers and all children reached above the by the United Kingdom Expert Consensus Group recommended level of 60 minutes moderate to vigorous physical activity per day.</p> <p>Conclusion</p> <p>A physical active transportation to school for two years is in pre-pubertal children not associated with a higher accrual of BMC or bone width than a passive mode of transportation, possibly due to the fact that the everyday physical activity in these pre-pubertal children, independent of the mode of school transportation, was high.</p
A prospective pilot clinical trial evaluating the utility of a dynamic near-infrared imaging device for characterizing suspicious breast lesions
Introduction:
Characterizing and differentiating between malignant tumors, benign tumors, and normal breast tissue is increasingly important in the patient presenting with breast problems. Near-infrared diffuse optical imaging and spectroscopy is capable of measuring multiple physiologic parameters of biological tissue systems and may have clinical applications for assessing the development and progression of neoplastic processes, including breast cancer. The currently available application of near-infrared imaging technology for the breast, however, is compromised by low spatial resolution, tissue heterogeneity, and interpatient variation.
Materials and methods:
We tested a dynamic near-infrared imaging schema for the characterization of suspicious breast lesions identified on diagnostic clinical ultrasound. A portable handheld near-infrared tissue imaging device (P-Scan; ViOptix Inc., Fremont, CA, USA) was utilized. An external mechanical compression force was applied to breast tissue. The tissue oxygen saturation and hemoglobin concentration were recorded simultaneously by the handheld near-infrared imaging device. Twelve categories of dynamic tissue parameters were derived based on real-time measurements of the tissue hemoglobin concentration and the oxygen saturation.
Results:
Fifty suspicious breast lesions were evaluated in 48 patients. Statistical analyses were carried out on 36 out of 50 datasets that satisfied our inclusion criteria. Suspicious breast lesions identified on diagnostic clinical ultrasound had lower oxygenation and higher hemoglobin concentration than the surrounding normal breast tissue. Furthermore, histopathologic-proven malignant breast tumors had a lower differential hemoglobin contrast (that is, the difference of hemoglobin concentration variability between the suspicious breast lesion and the normal breast parenchyma located remotely elsewhere within the ipsilateral breast) as compared with histopathologic-proven benign breast lesions.
Conclusion:
The proposed dynamic near-infrared imaging schema has the potential to differentiate benign processes from those of malignant breast tumors. Further development and refinement of the dynamic imaging device and additional subsequent clinical testing are necessary for optimizing the accuracy of detection
Reliability and validity of two frequently used self-administered physical activity questionnaires in adolescents
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