3,916 research outputs found

    Brahms\u27 Variations and Fugue on a Theme by Handel, Op. 24: A Study of the Technique of Harmonic Variation

    Get PDF
    It is the purpose of this study to isolate as much as possible a single technique, harmonic variation, and explore its techniques and uses through the study of a complete set of variations. The study is limited to harmonic concepts, procedures, and techniques used by the composer in the development of this particular set

    Familial influences on the full range of variability in attention and activity levels during adolescence: A longitudinal twin study

    Get PDF
    AbstractTo investigate familial influences on the full range of variability in attention and activity across adolescence, we collected maternal ratings of 339 twin pairs at ages 12, 14, and 16, and estimated the transmitted and new familial influences on attention and activity as measured by the Strengths and Weaknesses of Attention-Deficit/Hyperactivity Disorder Symptoms and Normal Behavior Scale. Familial influences were substantial for both traits across adolescence: genetic influences accounted for 54%–73% (attention) and 31%–73% (activity) of the total variance, and shared environmental influences accounted for 0%–22% of the attention variance and 13%–57% of the activity variance. The longitudinal stability of individual differences in attention and activity was largely accounted for by familial influences transmitted from previous ages. Innovations over adolescence were also partially attributable to familial influences. Studying the full range of variability in attention and activity may facilitate our understanding of attention-deficit/hyperactivity disorder's etiology and intervention.</jats:p

    Stepwise pumping approach to improve free phase light hydrocarbon recovery from unconfined aquifers

    Get PDF
    A stepwise, time-varying pumping approach is developed to improve free phase oil recovery of light non-aqueous phase liquids {LNAPL) from a homogeneous, unconfined aquifer. Stepwise pumping is used to contain the floating oil plume and obtain efficient free oil recovery. The pumping approach is developed using detailed simulations, multiple linear regression and graphical plots. The approach uses ARMOS©, an areal two-dimensional multiphase flow, finite-element simulation model. Systematic simulations of f~ oil area changes to pumping rates are analyzed. Pumping rates are determined that achieve LNAPL plume containment at different times (i.e. 90, 180 and 360 days) for a planning period of 360 days. These pumping rates are used in reverse order as a stepwise (monotonically increasing) pumping strategy. This stepwise pumping strategy is analyzed further by performing additional simulations at different pumping rates for the last pumping period. The final stepwise pumping strategy is varied by factors of -25% and +30% to evaluate sensitivity in the free oil recovery process. Stepwise pumping is compared to steady pumping rates to determine the best free oil recovery strategy. Stepwise pumping is shown to improve oil recovery by increasing recovered oil volume (11%) and decreasing residual oil (15%) when compared with traditional steady pumping strategies. The best stepwise pumping strategy recovers more free oil by reducing the amount of residual oil left in the system due to pumping drawdown. This stepwise pumping approach can be used to enhance free oil recovery and provide for cost-effective design and management of LNAPL cleanup

    Modeling technique for optimal recovery of immiscible light hydrocarbons as free product from contaminated aquifer

    Get PDF
    Contamination sites associated with light non-aqueous phase liquids {LNAPL) are numerous and represent difficult cleanup problems. Remediation methods for cleanup of LNAPL fluids in subsurface systems are continuously evolving with the development of various technologies for pump.-and~treat, soil venting, and in-situ bioremediation. Evaluating the effectiveness of remediation techniques as well as attempting to improve their efficiency has been a focus of many researchers, These efforts have included the development of computer simulation models to predict and analyze the fluid movement, entrapment, and mobilization of three~phase systems in porous media. The capability of computer models that not only simulate but optimize remediation processes are in great need. Simulation/optimization (S/0) models allow engineers to optimize processes and to make cost-effective design and management decisions when evaluating remediation strategies. An innovative approach is presented to optimize pumping to immobilize and recover the free product of a floating contaminant consisting of LNAPL\u27s. This determines the best pumping strategy to capture and remove the free oil product not left behind as residual oil. The approach combines detailed simulation, statistical analysis, and operations research optimization. This modeling technique derives regression equations describing system response to unit pumping stimuli. The statistical approach develops regression equations that represent free oil area within the system versus pumping. These equations are derived for multiple time steps and used in the S/0 model to determine the optimized pumping rates required to minimize free oil area and entrapped oil while maximizing free oil recovery and immobilizing the plume via a pump and oil recovery system. When compared with standard simulation techniques, this approach can save substantial computational time and improve remediation strategy design. Utilized is a modified version of US/REMAX, a linear or nonlinear simulation/optimization (S/0) model. US/REMAX can be used to analyze and optimize a variety of groundwater management problems. The modified version incorporates system responses generated externally using ARMOS plus regression analysis. ARMOS is a Z~D areal multiphase flow model. It has the capability of simulating spill, leakage, redistribution, or recovery of LNAPL materials. Application to a representative field problem illustrates the S/O model utility for problem analysis and remediation design. Potential applications of such an S/0 model are numerous providing optimized strategies for recovery of LNAPL spills

    Single nucleotide polymorphisms (SNPs) are highly conserved in rhesus (Macaca mulatta) and cynomolgus (Macaca fascicularis) macaques

    Get PDF
    Background: Macaca fascicularis (cynomolgus or longtail macaques) is the most commonly used nonhuman primate in biomedical research. Little is known about the genomic variation in cynomolgus macaques or how the sequence variants compare to those of the well-studied related species, Macaca mulatta (rhesus macaque). Previously we identified single nucleotide polymorphisms (SNPs) in portions of 94 rhesus macaque genes and reported that Indian and Chinese rhesus had largely different SNPs. Here we identify SNPs from some of the same genomic regions of cynomolgus macaques (from Indochina, Indonesia, Mauritius and the Philippines) and compare them to the SNPs found in rhesus. Results: We sequenced a portion of 10 genes in 20 cynomolgus macaques. We identified 69 SNPs in these regions, compared with 71 SNPs found in the same genomic regions of 20 Indian and Chinese rhesus macaques. Thirty six (52%) of the M. fascicularis SNPs were overlapping in both species. The majority (70%) of the SNPs found in both Chinese and Indian rhesus macaque populations were also present in M. fascicularis. Of the SNPs previously found in a single rhesus population, 38% (Indian) and 44% (Chinese) were also identified in cynomolgus macaques. In an alternative approach, we genotyped 100 cynomolgus DNAs using a rhesus macaque SNP array representing 53 genes and found that 51% (29/57) of the rhesus SNPs were present in M. fascicularis. Comparisons of SNP profiles from cynomolgus macaques imported from breeding centers in China (where M. fascicularis are not native) showed they were similar to those from Indochina. Conclusion: This study demonstrates a surprisingly high conservation of SNPs between M. fascicularis and M. mulatta, suggesting that the relationship of these two species is closer than that suggested by morphological and mitochondrial DNA analysis alone. These findings indicate that SNP discovery efforts in either species will generate useful resources for both macaque species. Identification of SNPs that are unique to regional populations of cynomolgus macaques indicates that location-specific SNPs could be used to distinguish monkeys of uncertain origin. As an example, cynomolgus macaques obtained from 2 different breeding centers in China were shown to have Indochinese ancestry.This work was supported by grants RR00163 and RR00166, from the National Center for Research Resources, National Institutes of Health

    Tattoo ink nanoparticles in skin tissue and fibroblasts

    Get PDF
    YesTattooing has long been practised in various societies all around the world and is becoming increasingly common and widespread in the West. Tattoo ink suspensions unquestionably contain pigments composed of nanoparticles, i.e., particles of sub-100 nm dimensions. It is widely acknowledged that nanoparticles have higher levels of chemical activity than their larger particle equivalents. However, assessment of the toxicity of tattoo inks has been the subject of little research and ink manufacturers are not obliged to disclose the exact composition of their products. This study examines tattoo ink particles in two fundamental skin components at the nanometre level. We use atomic force microscopy and light microscopy to examine cryosections of tattooed skin, exploring the collagen fibril networks in the dermis that contain ink nanoparticles. Further, we culture fibroblasts in diluted tattoo ink to explore both the immediate impact of ink pigment on cell viability and also to observe the interaction between particles and the cells

    Management of Children With Chronic Wet Cough and Protracted Bacterial Bronchitis CHEST Guideline and Expert Panel Report

    Get PDF
    BACKGROUND: Wet or productive cough is common in children with chronic cough. We formulated recommendations based on systematic reviews related to the management of chronic wet cough in children (aged METHODS: We used the CHEST expert cough panel\u27s protocol for systematic reviews and the American College of Chest Physicians (CHEST) methodologic guidelines and GRADE framework (the Grading of Recommendations Assessment, Development and Evaluation). Data from the systematic reviews in conjunction with patients\u27 values and preferences and the clinical context were used to form recommendations. Delphi methodology was used to obtain consensus for the recommendations/suggestions made. RESULTS: Combining data from the systematic reviews, we found high-quality evidence in children aged 4 weeks\u27 duration) wet/productive cough that using appropriate antibiotics improves cough resolution, and further investigations (eg, flexible bronchoscopy, chest CT scans, immunity tests) should be undertaken when specific cough pointers (eg, digital clubbing) are present. When the wet cough does not improve following 4 weeks of antibiotic treatment, there is moderate-quality evidence that further investigations should be considered to look for an underlying disease. New recommendations include the recognition of the clinical diagnostic entity of protracted bacterial bronchitis. CONCLUSIONS: Compared with the 2006 Cough Guidelines, there is now high-quality evidence for some, but not all, aspects of the management of chronic wet cough in specialist settings. However, further studies (particularly in primary health) are required

    Identification of tissue-specific, abiotic stress-responsive gene expression patterns in wine grape (Vitis vinifera L.) based on curation and mining of large-scale EST data sets

    Get PDF
    Background: Abiotic stresses, such as water deficit and soil salinity, result in changes in physiology, nutrient use, and vegetative growth in vines, and ultimately, yield and flavor in berries of wine grape, Vitis vinifera L. Large-scale expressed sequence tags (ESTs) were generated, curated, and analyzed to identify major genetic determinants responsible for stressadaptive responses. Although roots serve as the first site of perception and/or injury for many types of abiotic stress, EST sequencing in root tissues of wine grape exposed to abiotic stresses has been extremely limited to date. To overcome this limitation, large-scale EST sequencing was conducted from root tissues exposed to multiple abiotic stresses. Results: A total of 62,236 expressed sequence tags (ESTs) were generated from leaf, berry, and root tissues from vines subjected to abiotic stresses and compared with 32,286 ESTs sequenced from 20 public cDNA libraries. Curation to correct annotation errors, clustering and assembly of the berry and leaf ESTs with currently available V. vinifera full-length transcripts and ESTs yielded a total of 13,278 unique sequences, with 2302 singletons and 10,976 mapped to V. vinifera gene models. Of these, 739 transcripts were found to have significant differential expression in stressed leaves and berries including 250 genes not described previously as being abiotic stress responsive. In a second analysis of 16,452 ESTs from a normalized root cDNA library derived from roots exposed to multiple, shortterm, abiotic stresses, 135 genes with root-enriched expression patterns were identified on the basis of their relative EST abundance in roots relative to other tissues. Conclusions: The large-scale analysis of relative EST frequency counts among a diverse collection of 23 different cDNA libraries from leaf, berry, and root tissues of wine grape exposed to a variety of abiotic stress conditions revealed distinct, tissue-specific expression patterns, previously unrecognized stress-induced genes, and many novel genes with root-enriched mRNA expression for improving our understanding of root biology and manipulation of rootstock traits in wine grape. mRNA abundance estimates based on EST library-enriched expression patterns showed only modest correlations between microarray and quantitative, real-time reverse transcription-polymerase chain reaction (qRT-PCR) methods highlighting the need for deep-sequencing expression profiling methods

    Differential Acute Impacts of Sleeve Gastrectomy, Roux-en-Y Gastric Bypass Surgery and Matched Caloric Restriction Diet on Insulin Secretion, Insulin Effectiveness and Non-Esterified Fatty Acid Levels Among Patients with Type 2 Diabetes.

    Full text link
    peer reviewedBACKGROUND: Bariatric surgery is an increasingly common option for control of type 2 diabetes (T2D) and obesity. Mechanisms underlying rapid improvement of T2D after different types of bariatric surgery are not clear. Caloric deprivation and altered levels of non-esterified fatty acid (NEFA) have been proposed. This study examines how sleeve gastrectomy (SG), Roux-en-Y gastric bypass (GBP) or matched hypocaloric diet (DT) achieves improvements in T2D by characterising components of the glucose metabolism and NEFA levels before and 3 days after each intervention. METHODS: Plasma samples at five time points during oral glucose tolerance test (OGTT) from subjects with T2D undergoing GBP (N = 11) or SG (N = 12) were analysed for C-peptide, insulin and glucose before surgery and 3-day post-intervention or after DT (N = 5). Fasting palmitic, linoleic, oleic and stearic acid were measured. C-peptide measurements were used to model insulin secretion rate (ISR) using deconvolution. RESULTS: Subjects who underwent GBP surgery experienced the greatest improvement in glycaemia (median reduction in blood glucose (BG) from basal by 29 % [IQR -57, -18]) and the greatest reduction in all NEFA measured. SG achieved improvement in glycaemia with lower ISR and reduction in all but palmitoleic acid. DT subjects achieved improvement in glycaemia with an increase in ISR, 105 % [IQR, 20, 220] and stearic acid. CONCLUSIONS: GBP, SG and DT each improve glucose metabolism through different effects on pancreatic beta cell function, insulin sensitivity and free fatty acids

    The X^- Solution to the ^6Li and ^7Li Big Bang Nucleosynthesis Problems

    Full text link
    The 6^6Li abundance observed in metal poor halo stars appears to exhibit a plateau as a function of metallicity similar to that for 7^7Li, suggesting a big bang origin. However, the inferred primordial abundance of 6^6Li is ∼\sim1000 times larger than that predicted by standard big bang nucleosynthesis for the baryon-to-photon ratio inferred from the WMAP data. Also, the inferred 7^7Li primordial abundance is 3 times smaller than the big bang prediction. We here describe in detail a possible simultaneous solution to both the problems of underproduction of 6^6Li and overproduction of 7^7Li in big bang nucleosynthesis. This solution involves a hypothetical massive, negatively-charged leptonic particle that would bind to the light nuclei produced in big bang nucleosynthesis, but would decay long before it could be detected. We consider only the XX-nuclear reactions and assume that the effect of decay products is negligible, as would be the case if lifetime were large or the mass difference between the charged particle and its daughter were small. An interesting feature of this paradigm is that, because the particle remains bound to the existing nuclei after the cessation of the usual big bang nuclear reactions, a second longer epoch of nucleosynthesis can occur among XX-nuclei. We confirm that reactions in which the hypothetical particle is transferred can occur that greatly enhance the production of 6^6Li while depleting 7^7Li. We also identify a new reaction that destroys large amounts of 7^7Be, and hence reduces the ultimate 7^7Li abundance. Thus, big-bang nucleosynthesis in the presence of these hypothetical particles, together with or without an event of stellar processing, can simultaneously solve the two Li abundance problems.Comment: 18 pages, 7 figures, minor changes and references added, ApJ accepte
    • …
    corecore