6,811 research outputs found

    Reproductive and developmental effects of phthalate diesters in females.

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    Phthalate diesters, widely used in flexible plastics and consumer products, have become prevalent contaminants in the environment. Human exposure is ubiquitous and higher phthalate metabolite concentrations documented in patients using medications with phthalate-containing slow release capsules raises concerns for potential health effects. Furthermore, animal studies suggest that phthalate exposure can modulate circulating hormone concentrations and thus may be able to adversely affect reproductive physiology and the development of estrogen sensitive target tissues. Therefore, we conducted a systematic review of the epidemiological and experimental animal literature examining the relationship between phthalate exposure and adverse female reproductive health outcomes. The epidemiological literature is sparse for most outcomes studied and plagued by small sample size, methodological weaknesses, and thus fails to support a conclusion of an adverse effect of phthalate exposure. Despite a paucity of experimental animal studies for several phthalates, we conclude that there is sufficient evidence to suggest that phthalates are reproductive toxicants. However, we note that the concentrations needed to induce adverse health effects are high compared to the concentrations measured in contemporary human biomonitoring studies. We propose that the current patchwork of studies, potential for additive effects and evidence of adverse effects of phthalate exposure in subsequent generations and at lower concentrations than in the parental generation support the need for further study

    Optimal control of the propagation of a graph in inhomogeneous media

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    We study an optimal control problem for viscosity solutions of a Hamilton–Jacobi equation describing the propagation of a one-dimensional graph with the control being the speed function. The existence of an optimal control is proved together with an approximate controllability result in the H1H^{-1}-norm. We prove convergence of a discrete optimal control problem based on a monotone finite difference scheme and describe some numerical results

    Management of Chronic Staphylococcal Osteomyelitis of the Temporal Bone: The Use of Hyperbaric Oxygen

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    Hyperbaric oxygen (HBO) is an effective adjunct in the management of selected otolaryngologic problems including radiation-induced necrosis of the temporal hone, malignant external otitis, mandibular osteoradionecrosis and refractory osteomyelitis, soft tissue head and neck necrotizing fasciitis, compromised skin flaps and grafts, acute air or gas embolism, and otologic barotrauma. We describe the management of a patient with insidious Staphylococcus aureus osteomyelitis of the temporal bone by the use of HBO preoperatively and postoperatively in conjunction with surgical debridement. The possible application of angiogenic agents and tetracycline hone-labeling in combination with HBO therapy in the management of refractory neurotologic disease is discussed

    Special Education Teachers’ Self-Efficacy During the Times of a Global Pandemic

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    This quantitative dissertation aims to describe and compare the perception of special education teachers\u27 self-efficacy amid the COVID-19 pandemic using the practice of distance and their self-efficacy pre-pandemic using face-to-face instruction and describe the perceived valuable supports teachers received from educational leaders during the pandemic and considered valuable. The study population includes special education teachers teaching in inclusive settings before and during the pandemic in grades 6–12 in districts located in South Texas. The current study\u27s data was analyzed using a two-way factorial analysis of variance, with both factors including repeated measures within subjects (2 x 3). A descriptive statistical analysis was also conducted to show how teachers felt supported and how much they valued the professional development opportunities they got during the COVID-19 pandemic while they were teaching using distance learning. The three hypotheses presented in the study were validated. The results indicated a difference between face-to-face and distance learning modes of instruction. Furthermore, the study found a difference among the self-efficacy domains and interactions between modes of instruction and self-efficacy domains. The outcomes of this dissertation contribute to the limited amount of research conducted in the field of special education teachers\u27 perceptions of their self-efficacy levels while employing distance learning

    A Framework for Analyzing Cultural Considerations in Working with Young Clients Diagnosed with Autism Spectrum Disorder

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    Culture consists of beliefs, laws, customs, and manners that society deems to be socially appropriate. As culture influences how the individual behaves within society, it is important to recognize if and how cultural elements might influence the acceptance of behavioral treatments. The purpose of this literature review was to analyze culture with respect to the two most common reinforcers used in applied behavior analysis (ABA) research, edibles and praise. There were two components to this evaluation: a) an in-depth search of five country’s use of edibles and praise and b) a review of a scholarly behavior analytic journal. The in-depth analysis results indicated that the use of edibles and praise varied with each country. The article review results indicated that out of 73 articles meeting inclusion criteria, five provided a cultural description and of those one applied a modification based on the participants’ cultural needs

    Characterization of novel beta-galactosidase activity that contributes to glycoprotein degradation and virulence in Streptococcus pneumoniae.

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    The pneumococcus obtains its energy from the metabolism of host glycosides. Therefore, efficient degradation of host glycoproteins is integral to pneumococcal virulence. In search of novel pneumococcal glycosidases, we characterized the Streptococcus pneumoniae strain D39 protein encoded by SPD_0065 and found that this gene encodes a beta-galactosidase. The SPD_0065 recombinant protein released galactose from desialylated fetuin, which was used here as a model of glycoproteins found in vivo. A pneumococcal mutant with a mutation in SPD_0065 showed diminished beta-galactosidase activity, exhibited an extended lag period in mucin-containing defined medium, and cleaved significantly less galactose than the parental strain during growth on mucin. As pneumococcal beta-galactosidase activity had been previously attributed solely to SPD_0562 (bgaA), we evaluated the contribution of SPD_0065 and SPD_0562 to total beta-galactosidase activity. Mutation of either gene significantly reduced enzymatic activity, but beta-galactosidase activity in the double mutant, although significantly less than that in either of the single mutants, was not completely abolished. The expression of SPD_0065 in S. pneumoniae grown in mucin-containing medium or tissues harvested from infected animals was significantly upregulated compared to that in pneumococci from glucose-containing medium. The SPD_0065 mutant strain was found to be attenuated in virulence in a manner specific to the host tissue

    Fan Loops Observed by IRIS, EIS and AIA

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    A comprehensive study of the physical parameters of active region fan loops is presented using the observations recorded with the Interface Region Imaging Spectrometer (IRIS), the EUV Imaging Spectrometer (EIS) on-board Hinode and the Atmospheric Imaging Assembly (AIA) and the Helioseismic and Magnetic Imager (HMI) on-board the Solar Dynamics Observatory (SDO). The fan loops emerging from non-flaring AR~11899 (near the disk-center) on 19th November, 2013 are clearly discernible in AIA 171~{\AA} images and those obtained in \ion{Fe}{8} and \ion{Si}{7} images using EIS. Our measurements of electron densities reveal that the footpoints of these loops are approximately at constant pressure with electron densities of logNe=\log\,N_{e}= 10.1 cm3^{-3} at log[T/K]=5.15\log\,[T/K]=5.15 (\ion{O}{4}), and logNe=\log\,N_{e}= 8.9 cm3^{-3} at log[T/K]=6.15\log\,[T/K]=6.15 (\ion{Si}{10}). The electron temperature diagnosed across the fan loops by means of EM-Loci suggest that at the footpoints, there are two temperature components at log[T/K]=4.95\log\,[T/K]=4.95 and 5.95, which are picked-up by IRIS lines and EIS lines respectively. At higher heights, the loops are nearly isothermal at log[T/K]=5.95\log\,[T/K]=5.95, that remained constant along the loop. The measurement of Doppler shift using IRIS lines suggests that the plasma at the footpoints of these loops is predominantly redshifted by 2-3~km~s1^{-1} in \ion{C}{2}, 10-15~km~s1^{-1} in \ion{Si}{4} and  ~15{--}20~km~s1^{-1} in \ion{O}{4}, reflecting the increase in the speed of downflows with increasing temperature from log[T/K]=4.40\log\,[T/K]=4.40 to 5.15. These observations can be explained by low frequency nanoflares or impulsive heating, and provide further important constraints on the modeling of the dynamics of fan loops.Comment: Accepted for publication in The Astrophysical Journal; 8 Figures, 11 page
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