3,637 research outputs found

    The Palestinian Idea: Film, Media, and the Radical Imagination

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    This is a book review of The Palestinian Idea: Film, Media, and the Radical Imagination by Greg Burris

    Idiopathic Gingival Hyperplasia: A Case Report with a 17-Year Followup

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    This is a case report of a patient with idiopathic gingival hyperplasia and an undiagnosed genetic disorder that demonstrated static encephalopathy, mental retardation, developmental delay, seizures, hypotonia, and severe gingival hypertrophy. The clinical dental management and attempts to obtain a genetic diagnosis are described

    Effects of Flight Activity and Age on Oxidative Damage in the Honey Bee, Apis Mellifera

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    Frequent and Highly Aerobic Behaviors Likely Contribute to Naturally Occurring Stress, Accelerate Senescence and Limit Lifespan. to Understand How the Physiological and Cellular Mechanisms that Determine the Onset and Duration of Senescence Are Shaped by Behavioral Development and Behavioral Duration, We Exploited the Tractability of the Honeybee (Apis Mellifera) Model System. First, We Determined Whether a Cause-Effect Relationship Exists between Honeybee Flight and Oxidative Stress by Comparing Oxidative Damage Accrued from Intense Flight Bouts to Damage Accrued from D-Galactose Ingestion, Which Induces Oxidative Stress and Limits Lifespan in Other Insects. Second, We Experimentally Manipulated the Duration of Honeybee Flight Across a Range of Ages to Determine the Effects on Reactive Oxygen Species (ROS) Accumulation and Associated Enzymatic Antioxidant Protective Mechanisms. in Bees Fed D-Galactose, Lipid Peroxidation (Assessed by Measuring Malondialdehyde Levels) Was Higher Than in Bees Fed Sucrose and Age-Matched Bees with a High and Low Number of Flight Experiences Collected from a Colony. Bees with High Amounts of Flight Experience Exhibited Elevated 8-Hydroxy-2′-Deoxyguanosine, a Marker of Oxidative DNA Damage, Relative to Bees with Less Flight Experience. Bees with High Amounts of Flight Experience Also Showed Increased Levels of Pro-Oxidants (Superoxide and Hydrogen Peroxide) and Decreased or Unchanged Levels of Antioxidants (Superoxide Dismutase and Catalase). These Data Implicate an Imbalance of Pro- to Antioxidants in Flight-Associated Oxidative Stress and Reveal How Behavior Can Damage a Cell and Consequently Limit Lifespan

    Reinforcement learning with misspecified model classes

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    Real-world robots commonly have to act in complex, poorly understood environments where the true world dynamics are unknown. To compensate for the unknown world dynamics, we often provide a class of models to a learner so it may select a model, typically using a minimum prediction error metric over a set of training data. Often in real-world domains the model class is unable to capture the true dynamics, due to either limited domain knowledge or a desire to use a small model. In these cases we call the model class misspecified, and an unfortunate consequence of misspecification is that even with unlimited data and computation there is no guarantee the model with minimum prediction error leads to the best performing policy. In this work, our approach improves upon the standard maximum likelihood model selection metric by explicitly selecting the model which achieves the highest expected reward, rather than the most likely model. We present an algorithm for which the highest performing model from the model class is guaranteed to be found given unlimited data and computation. Empirically, we demonstrate that our algorithm is often superior to the maximum likelihood learner in a batch learning setting for two common RL benchmark problems and a third real-world system, the hydrodynamic cart-pole, a domain whose complex dynamics cannot be known exactly.United States. Office of Naval Research. Multidisciplinary University Research Initiative (N00014-11-1-0688

    Pre-pregnancy predictors of hypertension in pregnancy among Aboriginal and Torres Strait Islander women in north Queensland, Australia; a prospective cohort study

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    BACKGROUND Compared to other Australian women, Indigenous women are frequently at greater risk for hypertensive disorders of pregnancy. We examined pre-pregnancy factors that may predict hypertension in pregnancy in a cohort of Aboriginal and Torres Strait Islander women in north Queensland. METHODS Data on a cohort of 1009 Indigenous women of childbearing age (15–44 years) who participated in a 1998–2000 health screening program in north Queensland were combined with 1998–2008 Queensland hospitalisations data using probabilistic data linkage. Data on the women in the cohort who were hospitalised for birth (n = 220) were further combined with Queensland perinatal data which identified those diagnosed with hypertension in pregnancy. RESULTS Of 220 women who gave birth, 22 had hypertension in the pregnancy after their health check. The mean age of women with and without hypertension was similar (23.7 years and 23.9 years respectively) however Aboriginal women were more affected compared to Torres Strait Islanders. Pre-pregnancy adiposity and elevated blood pressure at the health screening program were predictors of a pregnancy affected by hypertension. After adjusting for age and ethnicity, each 1 cm increase in waist circumference showed a 4% increased risk for hypertension in pregnancy (PR 1.04; 95% CI; 1.02-1.06); each 1 point increase in BMI showed a 9% adjusted increase in risk (1.09; 1.04-1.14). For each 1 mmHg increase in baseline systolic blood pressure there was an age and ethnicity adjusted 6% increase in risk and each 1 mmHg increase in diastolic blood pressure showed a 7% increase in risk (1.06; 1.03-1.09 and 1.07; 1.03-1.11 respectively). Among those free of diabetes at baseline, the presence of the metabolic syndrome (International Diabetes Federation criteria) predicted over a three-fold increase in age-ethnicity-adjusted risk (3.5; 1.50-8.17). CONCLUSIONS Pre-pregnancy adiposity and features of the metabolic syndrome among these young Aboriginal and Torres Strait Islander women track strongly to increased risk of hypertension in pregnancy with associated risks to the health of babies.Sandra K Campbell, John Lynch, Adrian Esterman and Robyn McDermot

    The genomic landscape of thyroid cancer tumourigenesis and implications for immunotherapy

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    Thyroid cancer is the most prevalent endocrine malignancy that comprises mostly indolent differentiated cancers (DTCs) and less frequently aggressive poorly differentiated (PDTC) or anaplastic cancers (ATCs) with high mortality. Utilisation of next-generation sequencing (NGS) and advanced sequencing data analysis can aid in understanding the multi-step progression model in the development of thyroid cancers and their metastatic potential at a molecular level, promoting a targeted approach to further research and development of targeted treatment options including immunotherapy, especially for the aggressive variants. Tumour initiation and progression in thyroid cancer occurs through constitutional activation of the mitogen-activated protein kinase (MAPK) pathway through mutations in BRAF, RAS, mutations in the phosphatidylinositol-4,5-bisphosphate 3-kinase (PI3K) pathway and/or receptor tyrosine kinase fusions/translocations, and other genetic aberrations acquired in a stepwise manner. This review provides a summary of the recent genetic aberrations implicated in the development and progression of thyroid cancer and implications for immunotherapy

    Cooperative amyloid fibre binding and disassembly by the Hsp70 disaggregase

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    Although amyloid fibres are highly stable protein aggregates, a specific combination of human Hsp70 system chaperones can disassemble them, including fibres formed of α-synuclein, huntingtin, or Tau. Disaggregation requires the ATPase activity of the constitutively expressed Hsp70 family member, Hsc70, together with the J domain protein DNAJB1 and the nucleotide exchange factor Apg2. Clustering of Hsc70 on the fibrils appears to be necessary for disassembly. Here we use atomic force microscopy to show that segments of in vitro assembled α-synuclein fibrils are first coated with chaperones and then undergo bursts of rapid, unidirectional disassembly. Cryo-electron tomography and total internal reflection fluorescence microscopy reveal fibrils with regions of densely bound chaperones, preferentially at one end of the fibre. Sub-stoichiometric amounts of Apg2 relative to Hsc70 dramatically increase recruitment of Hsc70 to the fibres, creating localised active zones that then undergo rapid disassembly at a rate of ~ 4 subunits per second. The observed unidirectional bursts of Hsc70 loading and unravelling may be explained by differences between the two ends of the polar fibre structure

    Optics of cone photoreceptors in the chicken (Gallus gallus domesticus)

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    Vision is the primary sensory modality of birds, and its importance is evident in the sophistication of their visual systems. Coloured oil droplets in the cone photoreceptors represent an adaptation in the avian retina, acting as long-pass colour filters. However, we currently lack understanding of how the optical properties and morphology of component structures (e.g. oil droplet, mitochondrial ellipsoid and outer segment) of the cone photoreceptor influence the transmission of light into the outer segment and the ultimate effect they have on receptor sensitivity. In this study, we use data from microspectrophotometry, digital holographic microscopy and electron microscopy to inform electromagnetic models of avian cone photoreceptors to quantitatively investigate the integrated optical function of the cell. We find that pigmented oil droplets primarily function as spectral filters, not light collection devices, although the mitochondrial ellipsoid improves optical coupling between the inner segment and oil droplet. In contrast, unpigmented droplets found in violet-sensitive cones double sensitivity at its peak relative to other cone types. Oil droplets and ellipsoids both narrow the angular sensitivity of single cone photoreceptors, but not as strongly as those in human cones
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