320 research outputs found
Coherence-factor-based rough surface clutter suppression for forward-looking GPR imaging
We present an enhanced imaging procedure for suppression of the rough surface clutter arising in forward-looking ground-penetrating radar (FL-GPR) applications. The procedure is based on a matched filtering formulation of microwave tomographic imaging, and employs coherence factor (CF) for clutter suppression. After tomographic reconstruction, the CF is first applied to generate a "coherence map" of the region in front of the FL-GPR system illuminated by the transmitting antennas. A pixel-by-pixel multiplication of the tomographic image with the coherence map is then performed to generate the clutter-suppressed image. The effectiveness of the CF approach is demonstrated both qualitatively and quantitatively using electromagnetic modeled data of metallic and plastic shallow-buried targets
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Transition to kindergarten for children with disabilities: school practices and parent involvement
Using Pianta and Walsh's (1996) Contextual Systems Model (CSM), this study analyzed parent involvement in school as a key element for transition to kindergarten for children with disabilities and their families, along with the practices schools employ to improve school-family collaboration. Focusing on the relationship between the school system and the family/child system, this research explored the parent involvement and the factors influencing it using the views of Hoover-Dempsey and Sandler (1995), Eccles and Harold (1996), and Smith et al. (1997). The study drew from the Early Childhood Longitudinal Study Kindergarten Year of 1998-1999 (ECLS-K) a subsample of 1,016 children who have Individualized Education Programs (IEP). A profile of kindergarten-aged children with disabilities was created. School practices related to families were found to be low-intensity, formalized, and poorly correlated in number with degree of parent involvement. Parent involvement was assessed using seven items from the parent interviews. The items measured whether or not a parent participated in parent involvement activities with the schools during the kindergarten year. A composite variable measuring the number of types of activities a parent was involved in during the kindergarten year was created and used in a Linear Regression. A second parent involvement variable measuring the total number of activities that parents reported was created and used in a second Linear Regression. Parent involvement was unbalanced; i.e., parents tended to become involved in some types of parent involvement activities, but not in all types, and they chose different types. Family demographics (education, language), other family characteristics (perceptions, expectations, involvement at home) were found to be significant predictors for parent involvement. These results are discussed, and recommendations are offered
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Applying theories of capital to understand parent involvement at school as a component of family-school interaction : the special case of children with special needs
This study used a nationally representative dataset of 21,260 kindergartners, Early Childhood Longitudinal Study, Kindergarten Class of 1998-1999 (National Center for Education Statistics, 2001a), and a conceptual framework of theories of cultural and social capital (Bourdieu, 1986) embedded in an ecological framework (Bronfenbrenner, 2005) to identify unobserved socio-cultural classes in families of kindergartners and investigate these families' involvement at school. The study focused on the differences between families of children with and without disabilities.
Latent Class Analysis (LCA) was used for determining unobserved group membership in parents. First analysis revealed four socio-cultural classes: a low class of predominantly White, English-speaking, low education, and low socio-economic status (SES) parents; a middle class of predominantly White, educated, English-speaking, and high SES parents; a high class of educated, high SES parents, regardless of race or home language; and an "atypical" class of moderately educated, non-White, and non-English-speaking parents, regardless of their SES. Presence of disability did not influence socio-cultural class membership, but within each class, families of children with and without disabilities differed on a number of characteristics.
The second analysis identified three groups of parents based on school involvement: low, medium, and high involved. Group membership was predicted by four family factors: socio-cultural class, family structure, family-school ethnic match, and family's perception of school's involvement practices. Two-parent families, of higher socio-cultural class, with higher ethnic match, and with more positive perceptions of school practices belonged to the higher involvement group. School and teacher factors, including resources, views, and practices, had a weaker influence on parent involvement. School practices for parent-school involvement had only an indirect effect on parent involvement, through parent's perception of school practices. Disability status did not predict parent involvement group membership; however, within each group, the parents of children with disabilities were generally more involved, especially in the low-involvement group. The parents in the atypical and the low socio-cultural classes differed on a number of characteristics, including prevalence of disability and school involvement, differences that a classical SES categorization would more likely obscure. The study has important implications for informing better school-family connections
DIVERSITY OF FUNGI IN THE ALLIUM URSINUM L COVERED SOIL FOREST
In the soil,ecosystem there are differences in the diversity and spatial distribution of the fungal community. Forest soil samples were harvested in the spring season from the area of influence of plants of Allium ursinum L., in the western part of the country.The study of fungal diversity was carried out on the "soil grain method" on the sifted and ungrounded soil samples. The composition of fungal species is diverse, but there are also repetions (rehearsals) where the number of species is limited. The species present in both forest soil samples is Circinellaspp, followed by Penicillium spp and Aspergillus spp, the latter being isolated only from the sifted soil sample.The low-frequency species are: Torulaherbarum (species isolated from both soil samples), Chaetomium spirale (highlighted only in sampled (sifted) soil), Fusarium spp, Helminthosporiumspp and Mortierellamonospora, the last species isolated from the unsifted soil sample.Ă‚
A simple asthma prediction tool for preschool children with wheeze or cough
BACKGROUND
Many preschool children have wheeze or cough, but only some have asthma later. Existing prediction tools are difficult to apply in clinical practice or exhibit methodological weaknesses.
OBJECTIVE
We sought to develop a simple and robust tool for predicting asthma at school age in preschool children with wheeze or cough.
METHODS
From a population-based cohort in Leicestershire, United Kingdom, we included 1- to 3-year-old subjects seeing a doctor for wheeze or cough and assessed the prevalence of asthma 5 years later. We considered only noninvasive predictors that are easy to assess in primary care: demographic and perinatal data, eczema, upper and lower respiratory tract symptoms, and family history of atopy. We developed a model using logistic regression, avoided overfitting with the least absolute shrinkage and selection operator penalty, and then simplified it to a practical tool. We performed internal validation and assessed its predictive performance using the scaled Brier score and the area under the receiver operating characteristic curve.
RESULTS
Of 1226 symptomatic children with follow-up information, 345 (28%) had asthma 5 years later. The tool consists of 10 predictors yielding a total score between 0 and 15: sex, age, wheeze without colds, wheeze frequency, activity disturbance, shortness of breath, exercise-related and aeroallergen-related wheeze/cough, eczema, and parental history of asthma/bronchitis. The scaled Brier scores for the internally validated model and tool were 0.20 and 0.16, and the areas under the receiver operating characteristic curves were 0.76 and 0.74, respectively.
CONCLUSION
This tool represents a simple, low-cost, and noninvasive method to predict the risk of later asthma in symptomatic preschool children, which is ready to be tested in other populations
Ultrasound integrated neuronavigation – a standard tool for planning and guidance in the neurosurgery
Department of Neurosurgery, Institute of Neurology and Neurosurgery, Chisinau, the Republic of Moldova, Royal Hallamshire Hospital, Sheffield Teaching Hospital, Sheffield, United KingdomBackground: Intraoperative ultrasound provides a low cost real time imaging that is quick and simple to use. In recent years there has been a
significant improvement in the quality of ultrasound imaging. Ultrasound integrated neuronavigation can be used to optimize the lesion approach and
achieve a safe maximal resection, thereby improving the outcomes of the patients with different localizations and histologic types of brain tumors, vascular
pathology, spontaneous intracerebral hemorrhage.
Material and methods: From 2007 to 2010 in the Institute of Neurology and Neurosurgery 130 operations with the application of 2D intraoperative
ultrasound (US) were performed. From March to May 2012 17 patients underwent a surgical treatment with the usage the intraoperative ultrasound
integrated neuronavigation system.
Results: We have applied ultrasound neuronavigation system in 17 cases on the patients with diverse pathologies, including brain tumors
(craniopharyngeoma, corpus collosum and intracerebral glioblastoma, intraaxial glioma), vascular pathology (arteriovenous malformations, aneurysms),
spontaneous intracerebral hemorrhage. The application of ultrasound neuronavigation system helps in improving the postoperative outcomes of these
patients.
Conclusions: The integration of 3D US with neuronavigation technology has created an efficient and inexpensive tool for intraoperative imaging in
neurosurgery. The technology has been applied to optimize the surgery of brain tumors, but it has also been found useful in other procedures, such as
operations for aneurysms or arteriovenous malformations. Intraoperative ultrasound is easy to use and has a rapid assessment curve which makes it a
useful tool of the neurosurgeons’ intraoperative armamentarium
Measurement of anisotropic volumetric resistivity in lithium ion electrodes
Measurements of the electronic conductivity of lithium ion coatings are an important part of electrode development, particularly for thicker electrodes and in high power applications. A resistance measurement system with 46 probes has been used to characterise lithium ion electrodes, with different formulations and coat weights. The results show that the total through plane resistance is dominated by the interface resistance between the coating and the metal foil, rather than the volumetric resistivity of the coating. For coatings containing carbon nano-tubes, the in plane resistivities in the coating and perpendicular directions are different. A finite volume model was developed to help analyse and interpret the resistivity data
The Temperature Effect on Severely Deformed Aluminium by High Pressure Torsion
The process of deforming materials started to attract the interest of the researchers after the development of the severe plastic deformation techniques.
A number of aluminium samples were severe deformed by HPT method with different deformation degree. The researches follow to determine SPD effect on this material and temperature influence on fine aluminium structure. The paper present XRD and DSC results
Copy number variation of the beta-defensin genes in Europeans: no supporting evidence for association with lung function, chronic obstructive pulmonary disease or asthma
Lung function measures are heritable, predict mortality and are relevant in diagnosis of chronic obstructive pulmonary disease (COPD). COPD and asthma are diseases of the airways with major public health impacts and each have a heritable component. Genome-wide association studies of SNPs have revealed novel genetic associations with both diseases but only account for a small proportion of the heritability. Complex copy number variation may account for some of the missing heritability. A well-characterised genomic region of complex copy number variation contains beta-defensin genes (DEFB103, DEFB104 and DEFB4), which have a role in the innate immune response. Previous studies have implicated these and related genes as being associated with asthma or COPD. We hypothesised that copy number variation of these genes may play a role in lung function in the general population and in COPD and asthma risk. We undertook copy number typing of this locus in 1149 adult and 689 children using a paralogue ratio test and investigated association with COPD, asthma and lung function. Replication of findings was assessed in a larger independent sample of COPD cases and smoking controls. We found evidence for an association of beta-defensin copy number with COPD in the adult cohort (OR = 1.4, 95%CI:1.02–1.92, P = 0.039) but this finding, and findings from a previous study, were not replicated in a larger follow-up sample(OR = 0.89, 95%CI:0.72–1.07, P = 0.217). No robust evidence of association with asthma in children was observed. We found no evidence for association between beta-defensin copy number and lung function in the general populations. Our findings suggest that previous reports of association of beta-defensin copy number with COPD should be viewed with caution. Suboptimal measurement of copy number can lead to spurious associations. Further beta-defensin copy number measurement in larger sample sizes of COPD cases and children with asthma are needed
Breastfeeding, lung volumes and alveolar size at school-age
Background: Previous studies found larger lung volumes at school-age in formerly breastfed children, with some studies suggesting an effect modification by maternal asthma. We wanted to explore this further in children who had undergone extensive lung function testing. The current study aimed to assess whether breastfeeding was associated with larger lung volumes and, if so, whether all compartments were affected. We also assessed association of breastfeeding with apparent diffusion coefficient (ADC), which measures freedom of gas diffusion in alveolar-acinar compartments and is a surrogate of alveolar dimensions. Additionally, we assessed whether these effects were modified by maternal asthma.Methods: We analysed data from 111 children and young adults aged 11–21 years, who had participated in detailed lung function testing, including spirometry, plethysmography and measurement of ADC of 3Helium (3He) by MR. Information on breastfeeding came from questionnaires applied in early childhood (age 1–4 years). We determined the association between breastfeeding and these measurements using linear regression, controlling for potential confounders.Results: We did not find significant evidence for an association between duration of breastfeeding and lung volumes or alveolar dimensions in the entire sample. In breastfed children of mothers with asthma, we observed larger lung volumes and larger average alveolar size than in non-breastfed children, but the differences did not reach significance levels.Conclusions: Confirmation of effects of breastfeeding on lung volumes would have important implications for public health. Further investigations with larger sample sizes are warranted
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