892 research outputs found

    Water-Repellent TiO₂-Organic Dye-Based Air Filters for Efficient Visible-Light-Activated Photochemical Inactivation against Bioaerosols

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    Recently, bioaerosols, including the 2019 novel coronavirus, pose a serious threat to global public health. Herein, we introduce a visible-light-activated (VLA) antimicrobial air filter functionalized with titanium dioxide (TiO2)–crystal violet (CV) nanocomposites facilitating abandoned visible light from sunlight or indoor lights. The TiO2–CV based VLA antimicrobial air filters exhibit a potent inactivation rate of ∼99.98% and filtration efficiency of ∼99.9% against various bioaerosols. Under visible-light, the CV is involved in overall inactivation by inducing reactive oxygen species production both directly (CV itself) and indirectly (in combination with TiO2). Moreover, the susceptibility of the CV to humidity was significantly improved by forming a hydrophobic molecular layer on the TiO2 surface, highlighting its potential applicability in real environments such as exhaled or humid air. We believe this work can open a new avenue for designing and realizing practical antimicrobial technology using ubiquitous visible-light energy against the threat of infectious bioaerosols

    Acute effects of nicotine on visual search tasks in young adult smokers

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    Rationale Nicotine is known to improve performance on tests involving sustained attention and recent research suggests that nicotine may also improve performance on tests involving the strategic allocation of attention and working memory. Objectives We used measures of accuracy and response latency combined with eye-tracking techniques to examine the effects of nicotine on visual search tasks. Methods In experiment 1 smokers and non-smokers performed pop-out and serial search tasks. In experiment 2, we used a within-subject design and a more demanding search task for multiple targets. In both studies, 2-h abstinent smokers were asked to smoke one of their own cigarettes between baseline and tests. Results In experiment 1, pop-out search times were faster after nicotine, without a loss in accuracy. Similar effects were observed for serial searches, but these were significant only at a trend level. In experiment 2, nicotine facilitated a strategic change in eye movements resulting in a higher proportion of fixations on target letters. If the cigarette was smoked on the first trial (when the task was novel), nicotine additionally reduced the total number of fixations and refixations on all letters in the display. Conclusions Nicotine improves visual search performance by speeding up search time and enabling a better focus of attention on task relevant items. This appears to reflect more efficient inhibition of eye movements towards task irrelevant stimuli, and better active maintenance of task goals. When the task is novel, and therefore more difficult, nicotine lessens the need to refixate previously seen letters, suggesting an improvement in working memory

    Chiral U(1) flavor models and flavored Higgs doublets: the top FB asymmetry and the Wjj

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    We present U(1) flavor models for leptophobic Z' with flavor dependent couplings to the right-handed up-type quarks in the Standard Model, which can accommodate the recent data on the top forward-backward (FB) asymmetry and the dijet resonance associated with a W boson reported by CDF Collaboration. Such flavor-dependent leptophobic charge assignments generally require extra chiral fermions for anomaly cancellation. Also the chiral nature of U(1)' flavor symmetry calls for new U(1)'-charged Higgs doublets in order for the SM fermions to have realistic renormalizable Yukawa couplings. The stringent constraints from the top FB asymmetry at the Tevatron and the same sign top pair production at the LHC can be evaded due to contributions of the extra Higgs doublets. We also show that the extension could realize cold dark matter candidates.Comment: 40 pages, 10 figures, added 1 figure and extended discussion, accepted for publication in JHE

    Search for CP violation in D0 and D+ decays

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    A high statistics sample of photoproduced charm particles from the FOCUS (E831) experiment at Fermilab has been used to search for CP violation in the Cabibbo suppressed decay modes D+ to K-K+pi+, D0 to K-K+ and D0 to pi-pi+. We have measured the following CP asymmetry parameters: A_CP(K-K+pi+) = +0.006 +/- 0.011 +/- 0.005, A_CP(K-K+) = -0.001 +/- 0.022 +/- 0.015 and A_CP(pi-pi+) = +0.048 +/- 0.039 +/- 0.025 where the first error is statistical and the second error is systematic. These asymmetries are consistent with zero with smaller errors than previous measurements.Comment: 12 pages, 4 figure

    A Study of D0 --> K0(S) K0(S) X Decay Channels

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    Using data from the FOCUS experiment (FNAL-E831), we report on the decay of D0D^0 mesons into final states containing more than one KS0K^0_S. We present evidence for two Cabibbo favored decay modes, D0KS0KS0Kπ+D^0\to K^0_SK^0_S K^- \pi^+ and D0KS0KS0K+πD^0\to K^0_SK^0_S K^+ \pi^-, and measure their combined branching fraction relative to D0Kˉ0π+πD^0\to \bar{K} ^0\pi^+\pi^- to be Γ(D0KS0KS0K±π)Γ(D0Kˉ0π+π)\frac{\Gamma(D^0\to K^0_SK^0_SK^{\pm}\pi^{\mp})}{\Gamma(D^0\to \bar{K} ^0\pi^+\pi^-)} = 0.0106 ±\pm 0.0019 ±\pm 0.0010. Further, we report new measurements of Γ(D0KS0KS0KS0)Γ(D0Kˉ0π+π)\frac{\Gamma(D^0\to K^0_SK^0_SK^0_S)}{\Gamma(D^0\to \bar{K} ^0\pi^+\pi^-)} = 0.0179 ±\pm 0.0027 ±\pm 0.0026, Γ(D0K0Kˉ0)Γ(D0Kˉ0π+π)\frac{\Gamma(D^0\to K^0\bar{K} ^0)}{\Gamma(D^0\to \bar{K} ^0\pi^+\pi^-)} = 0.0144 ±\pm 0.0032 ±\pm 0.0016, and Γ(D0KS0KS0π+π)Γ(D0Kˉ0π+π)\frac{\Gamma(D^0\to K^0_SK^0_S\pi^+\pi^-)}{\Gamma(D^0\to \bar{K} ^0\pi^+\pi^-)} = 0.0208 ±\pm 0.0035 ±\pm 0.0021 where the first error is statistical and the second is systematic.Comment: 11 pages, 3 figures, typos correcte

    Ubiquitous healthy diatoms in the deep sea confirm deep carbon injection by the biological pump

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    The role of the ocean as a sink for CO2 is partially dependent on the downward transport of phytoplankton cells packaged within fast-sinking particles. However, whether such fast-sinking mechanisms deliver fresh organic carbon down to the deep bathypelagic sea and whether this mechanism is prevalent across the ocean requires confirmation. Here we report the ubiquitous presence of healthy photosynthetic cells, dominated by diatoms, down to 4,000 m in the deep dark ocean. Decay experiments with surface phytoplankton suggested that the large proportion (18%) of healthy photosynthetic cells observed, on average, in the dark ocean, requires transport times from a few days to a few weeks, corresponding to sinking rates (124–732 m d−1) comparable to those of fast-sinking aggregates and faecal pellets. These results confirm the expectation that fast-sinking mechanisms inject fresh organic carbon into the deep sea and that this is a prevalent process operating across the global oligotrophic ocean

    Epidemiology, radiology, and genetics of nicotine dependence in COPD

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    <p>Abstract</p> <p>Background</p> <p>Cigarette smoking is the principal environmental risk factor for developing COPD, and nicotine dependence strongly influences smoking behavior. This study was performed to elucidate the relationship between nicotine dependence, genetic susceptibility to nicotine dependence, and volumetric CT findings in smokers.</p> <p>Methods</p> <p>Current smokers with COPD (GOLD stage ≥ 2) or normal spirometry were analyzed from the COPDGene Study, a prospective observational study. Nicotine dependence was determined by the Fagerstrom test for nicotine dependence (FTND). Volumetric CT acquisitions measuring the percent of emphysema on inspiratory CT (% of lung <-950 HU) and gas trapping on expiratory CT (% of lung <-856 HU) were obtained. Genotypes for two SNPs in the CHRNA3/5 region (rs8034191, rs1051730) previously associated with nicotine dependence and COPD were analyzed for association to COPD and nicotine dependence phenotypes.</p> <p>Results</p> <p>Among 842 currently smoking subjects (335 COPD cases and 507 controls), 329 subjects (39.1%) showed high nicotine dependence. Subjects with high nicotine dependence had greater cumulative and current amounts of smoking. However, emphysema severity was negatively correlated with the FTND score in controls (ρ = -0.19, p < .0001) as well as in COPD cases (ρ = -0.18, p = 0.0008). Lower FTND score, male gender, lower body mass index, and lower FEV1 were independent risk factors for emphysema severity in COPD cases. Both CHRNA3/5 SNPs were associated with FTND in current smokers. An association of genetic variants in CHRNA3/5 with severity of emphysema was only found in former smokers, but not in current smokers.</p> <p>Conclusions</p> <p>Nicotine dependence was a negative predictor for emphysema on CT in COPD and control smokers. Increased inflammation in more highly addicted current smokers could influence the CT lung density distribution, which may influence genetic association studies of emphysema phenotypes.</p> <p>Trial registration</p> <p>ClinicalTrials (NCT): <a href="http://www.clinicaltrials.gov/ct2/show/NCT00608764">NCT00608764</a></p

    Local Search is Underused in Genetic Programming

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    Trujillo, L., Z-Flores, E., Juárez-Smith, P. S., Legrand, P., Silva, S., Castelli, M., ... Muñoz, L. (2018). Local Search is Underused in Genetic Programming. In R. Riolo, B. Worzel, B. Goldman, & B. Tozier (Eds.), Genetic Programming Theory and Practice XIV (pp. 119-137). [8] (Genetic and Evolutionary Computation). Springer. https://doi.org/10.1007/978-3-319-97088-2_8There are two important limitations of standard tree-based genetic programming (GP). First, GP tends to evolve unnecessarily large programs, what is referred to as bloat. Second, GP uses inefficient search operators that focus on modifying program syntax. The first problem has been studied extensively, with many works proposing bloat control methods. Regarding the second problem, one approach is to use alternative search operators, for instance geometric semantic operators, to improve convergence. In this work, our goal is to experimentally show that both problems can be effectively addressed by incorporating a local search optimizer as an additional search operator. Using real-world problems, we show that this rather simple strategy can improve the convergence and performance of tree-based GP, while also reducing program size. Given these results, a question arises: Why are local search strategies so uncommon in GP? A small survey of popular GP libraries suggests to us that local search is underused in GP systems. We conclude by outlining plausible answers for this question and highlighting future work.authorsversionpublishe

    Culture dependent and independent analyses of 16S rRNA and ATP citrate lyase genes : a comparison of microbial communities from different black smoker chimneys on the Mid-Atlantic Ridge

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    Author Posting. © Springer, 2008. This is the author's version of the work. It is posted here by permission of Springer for personal use, not for redistribution. The definitive version was published in Extremophiles 12 (2008): 627-640, doi:10.1007/s00792-008-0167-5.The bacterial and archaeal communities of three deep-sea hydrothermal vent systems located on the Mid-Atlantic Ridge (MAR; Rainbow, Logatchev and Broken Spur) were investigated using an integrated culture-dependent and independent approach. Comparative molecular phylogenetic analyses, using the 16S rRNA gene and the deduced amino acid sequences of the alpha and beta subunits of the ATP citrate lyase encoding genes were carried out on natural microbial communities, on an enrichment culture obtained from the Broken Spur chimney, and on novel chemolithoautotrophic bacteria and reference strains originally isolated from several different deep-sea vents. Our data showed that the three MAR hydrothermal vent chimneys investigated in this study host very different microbial assemblages. The microbial community of the Rainbow chimney was dominated by thermophilic, autotrophic, hydrogen-oxidizing, sulfur- and nitrate reducing Epsilonproteobacteria related to the genus Caminibacter. The detection of sequences related to sulfur-reducing bacteria and archaea (Archaeoglobus) indicated that thermophilic sulfate reduction might also be occurring at this site. The Logatchev bacterial community included several sequences related to mesophilic sulfur-oxidizing bacteria, while the archaeal component of this chimney was dominated by sequences related to the ANME-2 lineage, suggesting that anaerobic oxidation of methane may be occurring at this site. Comparative analyses of the ATP citrate lyase encoding genes from natural microbial communities suggested that Epsilonproteobacteria were the dominant primary producers using the reverse TCA cycle (rTCA) at Rainbow, while Aquificales of the genera Desulfurobacterium and Persephonella were prevalent in the Broken Spur chimney.This research was supported by NSF grants MCB 04-56676 (C.V.), OCE 03-27353 (C.V.), MCB 04-56689 (S.M.S.), a grant from the New Jersey Agricultural Experiment Station to C.V., and a NIH Ph.D. Training Program in Biotechnology Fellowship (NIH NIGMS 5 T32 GM08339) to J.V. M.H. was supported through a postdoctoral scholarship from the Woods Hole Oceanographic Institution
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