Monte Carlo tomographic reconstruction in SPECT impact of bootstrapping and number of generated events

In Single Photon Emission Computed Tomography (SPECT), 3D images usually reconstructed by performing a set of bidimensional (2D) analytical or iterative reconstructions can also be reconstructed using an iterative reconstruction algorithm involving a 3D projector. Accurate Monte Carlo (MC) simulations modeling all the physical effects that affect the imaging process can be used to estimate this projector. However, the accuracy of the projector is affected by the stochastic nature of MC simulations. In this paper, we study the accuracy of the reconstructed images with respect to the number of simulated histories used to estimate the MC projector. Furthermore, we study the impact of applying the bootstrapping technique when estimating the projectorComment: 15 pages, 9 figures, 2 table

Emotional and behavioural problems in children with Developmental Coordination Disorder: Exploring parent and teacher reports

BACKGROUND: Although characterised by motor impairments, children with Developmental Coordination Disorder (DCD) also show high rates of psychopathology (anxiety, depression, low self-esteem). Such findings have led to calls for the screening of mental health problems in this group. AIMS: To investigate patterns and profiles of emotional and behavioural problems in children with and without DCD, using the Strengths and Difficulties Questionnaire (SDQ). METHODS AND PROCEDURES: Teachers and parents completed SDQs for 30 children with DCD (7-10 years). Teacher ratings on the SDQ were also obtained from two typically-developing (TD) groups: 35 children matched for chronological age, and 29 younger children (4-7 years) matched by motor ability. OUTCOMES AND RESULTS: Group and individual analyses compared parent and teacher SDQ scores for children with DCD. Teacher reports showed that children with DCD displayed higher rates of emotional and behavioural problems (overall, and on each subscale of the SDQ) relative to their TD peers. No differences were observed between the two TD groups. Inspection of individual data points highlighted variability in the SDQ scores of the DCD group (across both teacher and parent ratings), with suggestions of elevated hyperactivity but comparably lower levels of conduct problems across this sample. Modest agreement was found between teacher and parent ratings of children with DCD on the SDQ. CONCLUSIONS AND IMPLICATIONS: There is a need to monitor levels of emotional and behavioural problems in children with DCD, from multiple informants

Examining the cognitive profile of children with Developmental Coordination Disorder

Background: While primarily a motor disorder, research considering the cognitive abilities in children with Developmental Coordination Disorder (DCD) is limited; even though these children often struggle academically. Aims: The present study aimed to characterise the IQ profile of children with and without DCD, and to identify whether children with DCD exhibit specific cognitive weaknesses. Methods and procedures: 104 children participated in the study. Fifty-two children (mean age, 9 years) with a diagnosis of DCD were matched to 52 typically-developing children by age and gender. Cognitive ability was assessed using the Wechsler Intelligence Scale for Children (WISC-IV). Outcomes and results: Children with DCD performed poorer than their peers on processing speed and working memory measures. Individual analyses revealed varied performance in the DCD group across all cognitive indices, despite displaying Full-Scale IQs in the typical range. Discriminant function analyses show processing speed and working memory performance predicted only 23% of between-group variability. Conclusions: Children with DCD present with a heterogeneous cognitive profile, lending support to individual case analyses in research and when designing educational assistance plans. The motorically-demanding nature of the WISC-IV processing speed tasks raises specific concerns about using this index of the IQ assessment in this population. Research and practical implications are raised

Synthesis and characterization of La_0.8Sr_1.2Co_0.5M_0.5O_4-? (M=Fe, Mn)

The M4+-containing K2NiF4-type phases La0.8Sr1.2Co0.5Fe0.5O4 and La0.8Sr1.2Co0.5Mn0.5O4 have been synthesized by a sol-gel procedure and characterized by X-ray powder diffraction, thermal analysis, neutron powder diffraction and Mössbauer spectroscopy. Oxide ion vacancies are created in these materials via reduction of M4+ to M3+ and of Co3+ to Co2+. The vacancies are confined to the equatorial planes of the K2NiF4-type structure. A partial reduction of Mn3+ to Mn2+ also occurs to achieve the oxygen stoichiometry in La0.8Sr1.2Co0.5Mn0.5O3.6. La0.8Sr1.2Co0.5Fe0.5O3.65 contains Co2+ and Fe3+ ions which interact antiferromagnetically and result in noncollinear magnetic order consistent with the tetragonal symmetry. Competing ferromagnetic and antiferromagnetic interactions in La0.8Sr1.2Co0.5Fe0.5O4, La0.8Sr1.2Co0.5Mn0.5O4 and La0.8Sr1.2Co0.5Mn0.5O3.6 induce spin glass properties in these phases

Properties of Low-Lying Heavy-Light Mesons

We present preliminary results for the B meson decay constant and masses of low-lying heavy-light mesons in the static limit. Calculations were performed on the lattice in the quenched approximation using multistate smearing functions generated from a Hamiltonian for a spinless relativistic quark. The 2S--1S and 1P--1S mass splittings are measured. Using the 1P--1S charmonium splitting to set the overall scale, the ground state decay constant, f_B, is 319 +- 11 (stat) MeV.Comment: 8 pages, 9 figures, UCLA/92/TEP/4

CP Violation in B Decays from Anomalous tbW Interactions

We calculate the effect of new CP violating interactions parameterized by an anomalous $tbW$ coupling on CP-odd observables in B decays. We find that couplings consistent with current bounds induce observable effects in some CP asymmetries that will be measured in B-factories. The new effects are sufficiently large that they can actually test specific models that give rise to these $tbW$ interactions.Comment: We have added a new section showing that the new effects are sufficiently large that they can be measured at a B-factor

Fully 3D Monte Carlo image reconstruction in SPECT using functional regions

Image reconstruction in Single Photon Emission Computed Tomography (SPECT) is affected by physical effects such as photon attenuation, Compton scatter and detector response. These effects can be compensated for by modeling the corresponding spread of photons in 3D within the system matrix used for tomographic reconstruction. The fully 3D Monte Carlo (F3DMC) reconstruction technique consists in calculating this system matrix using Monte Carlo simulations. The inverse problem of tomographic reconstruction is then solved using conventional iterative algorithms such as maximum likelihood expectation maximization (MLEM). Although F3DMC has already shown promising results, its use is currently limited by two major issues: huge size of the fully 3D system matrix and long computation time required for calculating a robust and accurate system matrix. To address these two issues, we propose to calculate the F3DMC system matrix using a spatial sampling matching the functional regions to be reconstructed. In this approach, different regions of interest can be reconstructed with different spatial sampling. For instance, a single value is reconstructed for a functional region assumed to contain uniform activity. To assess the value of this approach, Monte Carlo simulations have been performed using GATE. Results suggest that F3DMC reconstruction using functional regions improves quantitative accuracy compared to the F3DMC reconstruction method proposed so far. In addition, it considerably reduces disk space requirement and duration of the simulations needed to estimate the system matrix. The concept of functional regions might therefore make F3DMC reconstruction practically feasible.Comment: 6 pages, 3 figures, 3rd International Conference on maging Technologies in Biomedical Sciences : ITBS2005, Milos Island, Greece, 25-28 september 2005, submitted to NIM

Detroit Health Department: Lead Report 2016

The Epidemiology team at the Detroit Health Department rigorously stress- tested Detroit’s lead numbers. The findings suggest a true decline in EBLL levels rather than a decrease in lead testing or a change in the characteristics of the children who are being tested

Robotic Joint Replacement Surgery: Does Technology Improve Outcomes

Introduction: Osteoarthritis is a common disease that leads patients to seek Total Joint Replacement (TJR). Component misalignments leads to failure of TJR. Computer navigation enhances the precision of component alignment, but the addition of robotic guidance, can boost TJR to a higher level of accuracy. Methodology: This literature reviewed 29 English language peer reviewed articles from 2002 – 2013 and one website. A conceptual framework was adapted to explain benefits and barriers of adoption of robotic TJR. Results: A total of ten studies were reviewed with focus on more precise alignment, outcomes, length of stay, and costs. Cost to obtain robotic surgical equipment was found to be about $1 million with maintenance costs approaching$350,000. Discussion: Robotic techniques compared to conventional orthopedic surgery showed slight variances, in favor of robotic procedures. While hospitals have the potential to reduce costs and improve outcomes with robotic TJR, but the expenditure and maintenance have not been proven a clear ROI. Conclusion: As surgical robotic technology evolves in accuracy and accessibility, joint replacement surgery may benefit from improved precision and decreased healthcare costs. But, costs of equipment purchase, upkeep and surgeon training may impact its full potential in orthopedic surgery in the United States