605 research outputs found

    Hydrodynamics and equilibrium sediment dynamics of shallow, funnel-shaped tidal estuaries

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    https://scholarworks.wm.edu/vimsbooks/1033/thumbnail.jp

    The Case for Learned Index Structures

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    Indexes are models: a B-Tree-Index can be seen as a model to map a key to the position of a record within a sorted array, a Hash-Index as a model to map a key to a position of a record within an unsorted array, and a BitMap-Index as a model to indicate if a data record exists or not. In this exploratory research paper, we start from this premise and posit that all existing index structures can be replaced with other types of models, including deep-learning models, which we term learned indexes. The key idea is that a model can learn the sort order or structure of lookup keys and use this signal to effectively predict the position or existence of records. We theoretically analyze under which conditions learned indexes outperform traditional index structures and describe the main challenges in designing learned index structures. Our initial results show, that by using neural nets we are able to outperform cache-optimized B-Trees by up to 70% in speed while saving an order-of-magnitude in memory over several real-world data sets. More importantly though, we believe that the idea of replacing core components of a data management system through learned models has far reaching implications for future systems designs and that this work just provides a glimpse of what might be possible

    Physical and psychosocial health in pediatric uveitis patients

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    Background: To investigate the possible associations between childhood noninfectious uveitis and cardio-respiratory fitness, physical activity, health related quality of life and fatigue. Methods: Cross-sectional analysis of 23 patients with noninfectious uveitis, aged 8-18 years. BMI, exercise capacity, muscle strength and physical activity were measured. Health-related quality of life and fatigue were assessed. The results were compared to standardized values for age matched healthy children. Results: Twenty-three patients were included. Children with uveitis had a higher bodyweight and body mass index. Children with uveitis had lower cardio-respiratory fitness and they were less physically active, but they experienced a normal quality of life and normal fatigue. Parents of children with uveitis reported a lower quality of life and more fatigue for their children than parents of healthy children. Conclusion: Our study indicates that children with noninfectious uveitis are at risk of developing lower physical and psychosocial health

    Fe limitation decreases transcriptional regulation over the diel cycle in the model diatom Thalassiosira pseudonana.

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    Iron (Fe) is an important growth factor for diatoms and its availability is further restricted by changes in the carbonate chemistry of seawater. We investigated the physiological attributes and transcriptional profiles of the diatom Thalassiosira pseudonana grown on a day: night cycle under different CO2/pH and iron concentrations, that in combination generated available iron (Fe\u27) concentrations of 1160, 233, 58 and 12 pM. We found the light-dark conditions to be the main driver of transcriptional patterns, followed by Fe\u27 concentration and CO2 availability, respectively. At the highest Fe\u27 (1160 pM), 55% of the transcribed genes were differentially expressed between day and night, whereas at the lowest Fe\u27 (12 pM), only 28% of the transcribed genes displayed comparable patterns. While Fe limitation disrupts the diel expression patterns for genes in most central metabolism pathways, the diel expression of light- signaling molecules and glycolytic genes was relatively robust in response to reduced Fe\u27. Moreover, we identified a non-canonical splicing of transcripts encoding triose-phosphate isomerase, a key-enzyme of glycolysis, generating transcript isoforms that would encode proteins with and without an active site. Transcripts that encoded an active enzyme maintained a diel expression at low Fe\u27, while transcripts that encoded the non-active enzyme lost the diel expression. This work illustrates the interplay between nutrient limitation and transcriptional regulation over the diel cycle. Considering that future ocean conditions will reduce the availability of Fe in many parts of the oceans, our work identifies some of the regulatory mechanisms that may shape future ecological communities

    Organization of Photosystem I Polypeptides Examined by Chemical Cross-Linking

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    Physical activity in children with Juvenile Idiopathic Arthritis compared to controls

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    BACKGROUND: To compare physical activity (PA) in children with juvenile idiopathic arthritis (JIA) with controls and to analyse the effect of disease specific factors on PA in children with JIA treated according to current treatment regimes. METHODS: PA was measured with a 7-day activity diary and expressed as physical activity level (PAL). Moderate to vigorous physical activity (MVPA) (hours/day) and sedentary time (hours/day) was determined. In children with JIA, medication, the number of swollen and/or painful joints, disease activity, functional ability, pain and well-being was determined. Multivariate regression analysis was performed to analyze differences in PA between JIA and controls, adjusted for influences of age, gender, season, Body Mass Index (BMI) and to analyze predictors of PA in JIA patients. RESULTS: Seventy-six children with JIA (26 boys and 50 girls, mean ± SD age 10.0 ± 1.4 years) and 131 controls (49 boys and 82 girls, mean ± SD age 10.4 ± 1.2 years) participated in this study. Children with JIA had a significantly lower PAL (0.10, p = 0.01) corrected for age, BMI, gender and season. They spent less time in MVPA (0.41 h/day, p = 0.06) and had a significantly higher mean time spent in sedentary activities (0.59 h/day, p 0.02) compared to controls. The activity level of children with JIA was related to age, gender, season, feeling of well-being and pain. CONCLUSION: Children with JIA have a lower PAL, spent less time in MVPA and spent more time on sedentary activities compared to controls despite current medical treatment and PA encouragement. TRIAL REGISTRATION: Data of the children with JIA are from the Rheumates@work study ISRCTN92733069

    О параллельной обработке потока данных, адаптированной к области бит произвольной конфигурации

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    Предлагается модель операции свёртки арифметических многорядных двоичных кодов (МРК), которая учитывает неравномерность распределения бит данных по разрядам. На основе этой модели разрабатываются процедуры и методы свёртки МРК, которые позволяют снизить задержку на обработку.Пропонується модель операції згортки арифметичних багаторядних двійкових кодів (БРК), яка зважає на нерівномірність розподілу біт даних за разрядами. На основі цієї моделі розроблюються процедури і методи згортки БРК, які дозволяють зменшити затримку на обробку.Model of the compressing operation of arithmetic multi-row binary codes (MRC) is offered. In this model irregularity allocation of data bit per digits is considered. Procedures and methods of compressing MRC based on this model allow diminish delay of processing are designed (developed)

    Assessing the Contribution of Heme-Iron Acquisition to Staphylococcus aureus Pneumonia Using Computed Tomography

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    S. aureus acquires heme-iron using the iron regulated surface determinant (Isd) system and the heme transport system (Hts) with both systems showing critical importance in systemic models of infection. The contribution of heme-iron acquisition to staphylococcal pneumonia has not yet been elucidated. In addition, the use of computed tomography (CT) for the evaluation of staphylococcal pneumonia and its correlation to pathologic examination of infected lung tissue has not been performed to date. We have applied CT-based imaging to a murine model of staphylococcal pneumonia to determine the virulence contribution of heme-iron acquisition through the Hts and Isd systems.Mice were intranasally inoculated with approximately 1.0 x 10(8) colony forming units (CFU) of S. aureus. Lungs from mice infected with wild type S. aureus or strains deficient in isdB and isdH (DeltaisdBH) or htsA and isdE (DeltahtsADeltaisdE) were harvested at 24 hours. Histology, radiographic appearance by computed tomography (CT), percent mortality and bacterial burden were evaluated. Infection with S. aureus DeltaisdBH and DeltahtsADeltaisdE did not result in a statistically significant difference in mortality or bacterial burden as compared to controls. CT imaging of infected mice also did not reveal an appreciable difference between the various strains when compared to wild type, but did correlate with pathologic findings of pneumonia. However, a systemic model of infection using the DeltahtsADeltaisdE strain revealed a statistically significant decrease in bacterial burden in the lung, heart and kidneys.The development of staphylococcal pneumonia in this murine model is not dependent on hemoglobin binding or heme-iron uptake into S. aureus. However, this model does reveal that heme-iron acquisition contributes to the pathogenesis of systemic staphylococcal infections. In addition, CT imaging of murine lungs is an attractive adjunct to histologic analysis for the confirmation and staging of pneumonia
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