842 research outputs found

    Toner ink particle morphology in air-sparged hydrocyclone flotation deinking

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    Journal ArticleA series of pulping and flotation deinking tests were performed using a pilot-scale air-sparged hydrocyclone (ASH) flotation cell and a toner ink printed furnish. Microscopy studies indicate ink particles in both the flotation accepts and rejects are relatively flat. Many of the ink particles appear to be brittle and easily broken into smaller fragments. In some cases, toner ink particle softening had occurred as indicated by partial fusion of ink particles. Despite this softening, environmental scanning electron microscope (ESEM) images suggest toner ink particles were not elongated by the high shear conditions associated with the airsparged cyclone flotation cell

    Zeros of the i.i.d. Gaussian power series: a conformally invariant determinantal process

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    Consider the zero set of the random power series f(z)=sum a_n z^n with i.i.d. complex Gaussian coefficients a_n. We show that these zeros form a determinantal process: more precisely, their joint intensity can be written as a minor of the Bergman kernel. We show that the number of zeros of f in a disk of radius r about the origin has the same distribution as the sum of independent {0,1}-valued random variables X_k, where P(X_k=1)=r^{2k}. Moreover, the set of absolute values of the zeros of f has the same distribution as the set {U_k^{1/2k}} where the U_k are i.i.d. random variables uniform in [0,1]. The repulsion between zeros can be studied via a dynamic version where the coefficients perform Brownian motion; we show that this dynamics is conformally invariant.Comment: 37 pages, 2 figures, updated proof

    On Measuring Non-Recursive Trade-Offs

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    We investigate the phenomenon of non-recursive trade-offs between descriptional systems in an abstract fashion. We aim at categorizing non-recursive trade-offs by bounds on their growth rate, and show how to deduce such bounds in general. We also identify criteria which, in the spirit of abstract language theory, allow us to deduce non-recursive tradeoffs from effective closure properties of language families on the one hand, and differences in the decidability status of basic decision problems on the other. We develop a qualitative classification of non-recursive trade-offs in order to obtain a better understanding of this very fundamental behaviour of descriptional systems

    Robust Detection of Impaired Resting State Functional Connectivity Networks in Alzheimer's Disease Using Elastic Net Regularized Regression

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    The large number of multicollinear regional features that are provided by resting state (rs) fMRI data requires robust feature selection to uncover consistent networks of functional disconnection in Alzheimer's disease (AD). Here, we compared elastic net regularized and classical stepwise logistic regression in respect to consistency of feature selection and diagnostic accuracy using rs-fMRI data from four centers of the German resting-state initiative for diagnostic biomarkers (psymri.org), comprising 53 AD patients and 118 age and sex matched healthy controls. Using all possible pairs of correlations between the time series of rs-fMRI signal from 84 functionally defined brain regions as the initial set of predictor variables, we calculated accuracy of group discrimination and consistency of feature selection with bootstrap cross-validation. Mean areas under the receiver operating characteristic curves as measure of diagnostic accuracy were 0.70 in unregularized and 0.80 in regularized regression. Elastic net regression was insensitive to scanner effects and recovered a consistent network of functional connectivity decline in AD that encompassed parts of the dorsal default mode as well as brain regions involved in attention, executive control, and language processing. Stepwise logistic regression found no consistent network of AD related functional connectivity decline. Regularized regression has high potential to increase diagnostic accuracy and consistency of feature selection from multicollinear functional neuroimaging data in AD. Our findings suggest an extended network of functional alterations in AD, but the diagnostic accuracy of rs-fMRI in this multicenter setting did not reach the benchmark defined for a useful biomarker of AD

    Water supply of ancient Egyptian settlements: the role of the state. Overview of a relatively equitable scheme from the Old to New Kingdom (ca. 2543-1077 BC).

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    This is the final version of the article. It first appeared from Springer via http://dx.doi.org/10.1007/s12685-015-0150-xThe study of the textual and archaeological evidence shows that the water supply of the settlements of ancient Egypt seems to have worked on a simple and a relatively equitable scheme, at least from the Old Kingdom until the New Kingdom (ca. 2543-1077). The water supply of the inhabitants was completely managed by the state, through the local administration which was charged to bring the water, in general from a rural area, into towns and cities and to redistribute it to the inhabitants. The method of supply is illustrated by several sources of evidence, in particular by the well known case of the "water-carriers" of the village of Deir el-Medina. Thus, drawing together text and archaeology, this paper will demonstrate that over an extended period, even when the city was far from a water source, the state did not set up complex installations such as pipe networks or wells to bring water, but preferred a simpler system using the manpower available

    Somatic Accumulation of GluA1-AMPA Receptors Leads to Selective Cognitive Impairments in Mice

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    © 2018 Bannerman, Borchardt, Jensen, Rozov, Haj-Yasein, Burnashev, Zamanillo, Bus, Grube, Adelmann, Rawlins and Sprengel. The GluA1 subunit of the L-α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptor (AMPAR) plays a crucial, but highly selective, role in cognitive function. Here we analyzed AMPAR expression, AMPAR distribution and spatial learning in mice (Gria1R/R), expressing the “trafficking compromised” GluA1(Q600R) point mutation. Our analysis revealed somatic accumulation and reduction of GluA1(Q600R) and GluA2, but only slightly reduced CA1 synaptic localization in hippocampi of adult Gria1R/R mice. These immunohistological changes were accompanied by a strong reduction of somatic AMPAR currents in CA1, and a reduction of plasticity (short-term and long-term potentiation, STP and LTP, respectively) in the CA1 subfield following tetanic and theta-burst stimulation. Nevertheless, spatial reference memory acquisition in the Morris water-maze and on an appetitive Y-maze task was unaffected in Gria1R/R mice. In contrast, spatial working/short-term memory during both spontaneous and rewarded alternation tasks was dramatically impaired. These findings identify the GluA1(Q600R) mutation as a loss of function mutation that provides independent evidence for the selective role of GluA1 in the expression of short-term memory

    Evaluation of simulated CO<sub>2</sub> power plant plumes from six high-resolution atmospheric transport models

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    Global anthropogenic CO2 sources are dominated by power plants and large industrial facilities. Quantifying the emissions of these point sources is therefore one of the main goals of the planned constellation of anthropogenic CO2 monitoring satellites (CO2M) of the European Copernicus program. Atmospheric transport models may be used to study the capabilities of such satellites through observing system simulation experiments and to quantify emissions in an inverse modelling framework. How realistically the CO2 plumes of power plants can be simulated and how strongly the results may depend on model type and resolution, however, is not well known due to a lack of observations available for benchmarking. Here, we use the unique data set of aircraft in-situ and remote sensing observations collected during the CoMet measurement campaign down-wind of the coal fired power plants at Bełchatów in Poland and Jaenschwalde in Germany in 2018 to evaluate the simulations of six different atmospheric transport models

    Population gene introgression and high genome plasticity for the zoonotic pathogen Streptococcus agalactiae

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    The influence that bacterial adaptation (or niche partitioning) within species has on gene spillover and transmission among bacteria populations occupying different niches is not well understood. Streptococcus agalactiae is an important bacterial pathogen that has a taxonomically diverse host range making it an excellent model system to study these processes. Here we analyze a global set of 901 genome sequences from nine diverse host species to advance our understanding of these processes. Bayesian clustering analysis delineated twelve major populations that closely aligned with niches. Comparative genomics revealed extensive gene gain/loss among populations and a large pan-genome of 9,527 genes, which remained open and was strongly partitioned among niches. As a result, the biochemical characteristics of eleven populations were highly distinctive (significantly enriched). Positive selection was detected and biochemical characteristics of the dispensable genes under selection were enriched in ten populations. Despite the strong gene partitioning, phylogenomics detected gene spillover. In particular, tetracycline resistance (which likely evolved in the human-associated population) from humans to bovine, canines, seals, and fish, demonstrating how a gene selected in one host can ultimately be transmitted into another, and biased transmission from humans to bovines was confirmed with a Bayesian migration analysis. Our findings show high bacterial genome plasticity acting in balance with selection pressure from distinct functional requirements of niches that is associated with an extensive and highly partitioned dispensable genome, likely facilitating continued and expansive adaptation

    The frequency of genes encoding three putative group B streptococcal virulence factors among invasive and colonizing isolates

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    BACKGROUND: Group B Streptococcus (GBS) causes severe infections in very young infants and invasive disease in pregnant women and adults with underlying medical conditions. GBS pathogenicity varies between and within serotypes, with considerable variation in genetic content between strains. Three proteins, Rib encoded by rib, and alpha and beta C proteins encoded by bca and bac, respectively, have been suggested as potential vaccine candidates for GBS. It is not known, however, whether these genes occur more frequently in invasive versus colonizing GBS strains. METHODS: We screened 162 invasive and 338 colonizing GBS strains from different collections using dot blot hybridization to assess the frequency of bca, bac and rib. All strains were defined by serotyping for capsular type, and frequency differences were tested using the Chi square test. RESULTS: Genes encoding the beta C protein (bac) and Rib (rib) occurred at similar frequencies among invasive and colonizing isolates, bac (20% vs. 23%), and rib (28% vs. 20%), while the alpha (bca) C protein was more frequently found in colonizing strains (46%) vs, invasive (29%). Invasive strains were associated with specific serotype/gene combinations. CONCLUSION: Novel virulence factors must be identified to better understand GBS disease
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