3,593 research outputs found

    Probing non-standard decoherence effects with solar and KamLAND neutrinos

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    It has been speculated that quantum gravity might induce a "foamy" space-time structure at small scales, randomly perturbing the propagation phases of free-streaming particles (such as kaons, neutrons, or neutrinos). Particle interferometry might then reveal non-standard decoherence effects, in addition to standard ones (due to, e.g., finite source size and detector resolution.) In this work we discuss the phenomenology of such non-standard effects in the propagation of electron neutrinos in the Sun and in the long-baseline reactor experiment KamLAND, which jointly provide us with the best available probes of decoherence at neutrino energies E ~ few MeV. In the solar neutrino case, by means of a perturbative approach, decoherence is shown to modify the standard (adiabatic) propagation in matter through a calculable damping factor. By assuming a power-law dependence of decoherence effects in the energy domain (E^n with n = 0,+/-1,+/-2), theoretical predictions for two-family neutrino mixing are compared with the data and discussed. We find that neither solar nor KamLAND data show evidence in favor of non-standard decoherence effects, whose characteristic parameter gamma_0 can thus be significantly constrained. In the "Lorentz-invariant" case n=-1, we obtain the upper limit gamma_0<0.78 x 10^-26 GeV at 95% C.L. In the specific case n=-2, the constraints can also be interpreted as bounds on possible matter density fluctuations in the Sun, which we improve by a factor of ~ 2 with respect to previous analyses.Comment: Minor changes. Version accepted for publication in Phys. Rev.

    Probing Sterile Neutrino Parameters with Double Chooz, Daya Bay and RENO

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    In this work, we present a realistic analysis of the potential of the present-day reactor experiments Double Chooz, Daya Bay and RENO for probing the existence of sterile neutrinos. We present exclusion regions for sterile oscillation parameters for each of these experiments, using simulations with realistic estimates of systematic errors and detector resolutions, and compare the sterile parameter sensitivity regions we obtain with the existing bounds from other reactor experiments. We find that these experimental set-ups give significant bounds on the parameter \Theta_{ee} especially in the low sterile oscillation region 0.01 < \Delta m_{41}^2 < 0.05 eV^2. These bounds can add to our understanding of the sterile neutrino sector since there is still a tension in the allowed regions from different experiments for sterile parameters.Comment: 12 pages, 5 figure

    Where we are on θ13\theta_{13}: addendum to "Global neutrino data and recent reactor fluxes: status of three-flavour oscillation parameters"

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    In this addendum to arXiv:1103.0734 we consider the recent results from long-baseline νμνe\nu_\mu\to\nu_e searches at the T2K and MINOS experiments and investigate their implications for the mixing angle θ13\theta_{13} and the leptonic Dirac CP phase δ\delta. By combining the 2.5σ2.5\sigma indication for a non-zero value of θ13\theta_{13} coming from T2K data with global neutrino oscillation data we obtain a significance for θ13>0\theta_{13} > 0 of about 3σ3\sigma with best fit points sin2θ13=0.013(0.016)\sin^2\theta_{13} = 0.013(0.016) for normal (inverted) neutrino mass ordering. These results depend somewhat on assumptions concerning the analysis of reactor neutrino data.Comment: 5 pages, 2 figures and 1 tabl

    Rational Design of Sustainable Liquid Microcapsules for Spontaneous Fragrance Encapsulation

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    The high volatility, water-immiscibility, and light/oxygen-sensitivity of most aroma compounds represent a challenge to their incorporation in liquid consumer products. Current encapsulation methods entail the use of petroleum-based materials, initiators, and crosslinkers as well as mixing, heating, and purification steps. Hence, more efficient and eco-friendly approaches to encapsulation must be sought. Herein, we propose a simple method by making use of a pre-formed amphiphilic polymer and employing the Hansen Solubility Parameters approach to determine which fragrances could be encapsulated by spontaneous coacervation in water. The coacervates do not precipitate as solids but they remain suspended as colloidally stable liquid microcapsules, as demonstrated by fluorescence correlation spectroscopy. The effective encapsulation of fragrance is proven through confocal Raman spectroscopy, while the structure of the capsules is investigated by means of cryo FIB/SEM, confocal laser scanning microscopy, and small-angle X-ray scattering

    Observables sensitive to absolute neutrino masses: A reappraisal after WMAP-3y and first MINOS results

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    In the light of recent neutrino oscillation and non-oscillation data, we revisit the phenomenological constraints applicable to three observables sensitive to absolute neutrino masses: The effective neutrino mass in single beta decay (m_beta); the effective Majorana neutrino mass in neutrinoless double beta decay (m_2beta); and the sum of neutrino masses in cosmology (Sigma). In particular, we include the constraints coming from the first Main Injector Neutrino Oscillation Search (MINOS) data and from the Wilkinson Microwave Anisotropy Probe (WMAP) three-year (3y) data, as well as other relevant cosmological data and priors. We find that the largest neutrino squared mass difference is determined with a 15% accuracy (at 2-sigma) after adding MINOS to world data. We also find upper bounds on the sum of neutrino masses Sigma ranging from ~2 eV (WMAP-3y data only) to ~0.2 eV (all cosmological data) at 2-sigma, in agreement with previous studies. In addition, we discuss the connection of such bounds with those placed on the matter power spectrum normalization parameter sigma_8. We show how the partial degeneracy between Sigma and sigma_8 in WMAP-3y data is broken by adding further cosmological data, and how the overall preference of such data for relatively high values of sigma_8 pushes the upper bound of Sigma in the sub-eV range. Finally, for various combination of data sets, we revisit the (in)compatibility between current Sigma and m_2beta constraints (and claims), and derive quantitative predictions for future single and double beta decay experiments.Comment: 18 pages, including 7 figure

    Prognostic significance of high-grade dysplasia in colorectal adenomas.

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    Aim  Colonoscopy to detect and remove polyps has contributed to a reduction in colorectal carcinoma. Three-year follow up is recommended for patients considered to be at high risk (at least three adenomas, adenoma ≥ 1 cm, villous or high-grade features). Our study focused on patients diagnosed with high-grade dysplasia with regard to initial management and follow up. Method  A search of patients who had had endoscopic removal of a high-grade adenoma was carried out. Patients with the following were excluded: follow up of \u3c 1 year, polyposis syndromes, prior colon cancer and a diagnosis of adenocarcinoma within 6 months following initial diagnosis. Results  Eighty-three patients treated between 1999 and 2007 for high-grade dysplasia (HGD) in a colorectal adenoma were identified. Over a median follow-up period of 4 years, 53 (64%) developed further adenomatous polyps. Among these, 7% had an adenoma with HGD or an adenocarcinoma. In all these patients, the initial high-grade adenoma was \u3e 1 cm in diameter. Initial follow-up colonoscopy was performed on average 7 months following the initial diagnosis. Ten per cent of patients underwent prophylactic segmental resection, and 6% received argon laser therapy. Conclusion  The study demonstrates that patients who have a colorectal adenoma \u3e 1 cm with HGD may be at high risk of developing further adenomas with HGD or carcinoma. Close follow up is warranted

    Observables sensitive to absolute neutrino masses: Constraints and correlations from world neutrino data

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    In the context of three-flavor neutrino mixing, we present a thorough study of the phenomenological constraints applicable to three observables sensitive to absolute neutrino masses: The effective neutrino mass in Tritium beta decay (m_beta); the effective Majorana neutrino mass in neutrinoless double beta decay (m_2beta); and the sum of neutrino masses in cosmology (Sigma). We discuss the correlations among these variables which arise from the combination of all the available neutrino oscillation data, in both normal and inverse neutrino mass hierarchy. We set upper limits on m_beta by combining updated results from the Mainz and Troitsk experiments. We also consider the latest results on m_2beta from the Heidelberg-Moscow experiment, both with and without the lower bound claimed by such experiment. We derive upper limits on Sigma from an updated combination of data from the Wilkinson Microwave Anisotropy Probe (WMAP) satellite and the 2 degrees Fields (2dF) Galaxy Redshifts Survey, with and without Lyman-alpha forest data from the Sloan Digital Sky Survey (SDSS), in models with a non-zero running of the spectral index of primordial inflationary perturbations. The results are discussed in terms of two-dimensional projections of the globally allowed region in the (m_beta,m_2beta,Sigma) parameter space, which neatly show the relative impact of each data set. In particular, the (in)compatibility between Sigma and m_2beta constraints is highlighted for various combinations of data. We also briefly discuss how future neutrino data (both oscillatory and non-oscillatory) can further probe the currently allowed regions.Comment: 17 pages (RevTeX) + 7 figures (PostScript). Minor changes in text; references added; results unchanged. To appear in PR

    A Common Class of Transcripts with 5\u27-Intron Depletion, Distinct Early Coding Sequence Features, and N1-Methyladenosine Modification [preprint]

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    Introns are found in 5\u27 untranslated regions (5\u27UTRs) for 35% of all human transcripts. These 5\u27UTR introns are not randomly distributed: genes that encode secreted, membrane-bound and mitochondrial proteins are less likely to have them. Curiously, transcripts lacking 5\u27UTR introns tend to harbor specific RNA sequence elements in their early coding regions. To model and understand the connection between coding-region sequence and 5\u27UTR intron status, we developed a classifier that can predict 5\u27UTR intron status with \u3e80% accuracy using only sequence features in the early coding region. Thus, the classifier identifies transcripts with 5\u27 proximal-intron-minus-like-coding regions ( 5IM transcripts). Unexpectedly, we found that the early coding sequence features defining 5IM transcripts are widespread, appearing in 21% of all human RefSeq transcripts. The 5IM class of transcripts is enriched for non-AUG start codons, more extensive secondary structure both preceding the start codon and near the 5\u27 cap, greater dependence on eIF4E for translation, and association with ER-proximal ribosomes. 5IM transcripts are bound by the Exon Junction Complex (EJC) at non-canonical 5\u27 proximal positions. Finally, N1-methyladenosines are specifically enriched in the early coding regions of 5IM transcripts. Taken together, our analyses point to the existence of a distinct 5IM class comprising ~20% of human transcripts. This class is defined by depletion of 5\u27 proximal introns, presence of specific RNA sequence features associated with low translation efficiency, N1-methyladenosines in the early coding region, and enrichment for non-canonical binding by the Exon Junction Complex

    A common class of transcripts with 5\u27-intron depletion, distinct early coding sequence features, and N1-methyladenosine modification

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    Introns are found in 5\u27 untranslated regions (5\u27UTRs) for 35% of all human transcripts. These 5\u27UTR introns are not randomly distributed: Genes that encode secreted, membrane-bound and mitochondrial proteins are less likely to have them. Curiously, transcripts lacking 5\u27UTR introns tend to harbor specific RNA sequence elements in their early coding regions. To model and understand the connection between coding-region sequence and 5\u27UTR intron status, we developed a classifier that can predict 5\u27UTR intron status with \u3e 80% accuracy using only sequence features in the early coding region. Thus, the classifier identifies transcripts with 5\u27 proximal-intron-minus-like-coding regions ( 5IM transcripts). Unexpectedly, we found that the early coding sequence features defining 5IM transcripts are widespread, appearing in 21% of all human RefSeq transcripts. The 5IM class of transcripts is enriched for non-AUG start codons, more extensive secondary structure both preceding the start codon and near the 5\u27 cap, greater dependence on eIF4E for translation, and association with ER-proximal ribosomes. 5IM transcripts are bound by the exon junction complex (EJC) at noncanonical 5\u27 proximal positions. Finally, N1-methyladenosines are specifically enriched in the early coding regions of 5IM transcripts. Taken together, our analyses point to the existence of a distinct 5IM class comprising approximately 20% of human transcripts. This class is defined by depletion of 5\u27 proximal introns, presence of specific RNA sequence features associated with low translation efficiency, N1-methyladenosines in the early coding region, and enrichment for noncanonical binding by the EJC
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