5,430 research outputs found
Near-arcsecond resolution observations of the hot corino of the solar type protostar IRAS 16293-2422
Complex organic molecules have previously been discovered in solar type
protostars, raising the questions of where and how they form in the envelope.
Possible formation mechanisms include grain mantle evaporation, interaction of
the outflow with its surroundings or the impact of UV/X-rays inside the
cavities. In this Letter we present the first interferometric observations of
two complex molecules, CH3CN and HCOOCH3, towards the solar type protostar
IRAS16293-2422. The images show that the emission originates from two compact
regions centered on the two components of the binary system. We discuss how
these results favor the grain mantle evaporation scenario and we investigate
the implications of these observations for the chemical composition and
physical and dynamical state of the two components.Comment: 5 pages (apjemulate), 2 figures; accepted by ApJ
Creative small settlements. Culture-based solutions for local sustainable development.
Culture can play a fundamental role in fostering sustainable patterns of urban and regional development. This is the message of the Global Report âCulture for Sustainable Urban Developmentâ, which UNESCO has coordinated for the UN-HABITAT III Conference (Quito, October 2016). The Global Report shows that a promising culture-based vision of urban development is flourishing in different forms in several cities across the world. Even small and medium settlements located at the periphery of large cities or within their metropolitan areas, and normally associated with marginalisation or deprivation, have the potential to fully utilise their cultural resources, in both tangible (urban and architectural heritage, cultural infrastructure, etc.) and intangible form (skills, knowledge, competencies). However these small settlements, and their respective communities, require different analytical tools in order to understand their complexity and ad hoc policies to manage their assets in sustainable forms.
This research report aims to show ways to understand culture and creativity in small settlements, by collecting a series of international case studies that form the backbone of the chapter 10 of the UNESCO Global Report on urban-rural linkages and titled 'Culture as a tool to achieve harmonious territorial development'. This can allow a wider dissemination of the theoretical underpinnings and the comparative findings of a research conducted during 2015 and 2016 by several research units all over the world
Universal behavior of two-dimensional bosonic gases at Berezinskii-Kosterlitz-Thouless transitions
We study the universal critical behavior of two-dimensional (2D) lattice
bosonic gases at the Berezinskii-Kosterlitz-Thouless (BKT) transition, which
separates the low-temperature superfluid phase from the high-temperature normal
phase. For this purpose, we perform quantum Monte Carlo simulations of the
hard-core Bose-Hubbard (BH) model at zero chemical potential. We determine the
critical temperature by using a matching method that relates finite-size data
for the BH model with corresponding data computed in the classical XY model. In
this approach, the neglected scaling corrections decay as inverse powers of the
lattice size L, and not as powers of 1/lnL, as in more standard approaches,
making the estimate of the critical temperature much more reliable. Then, we
consider the BH model in the presence of a trapping harmonic potential, and
verify the universality of the trap-size dependence at the BKT critical point.
This issue is relevant for experiments with quasi-2D trapped cold atoms.Comment: 17 pages, 12 figs, final versio
First detection of triply-deuterated methanol
We report the first detection of triply-deuterated methanol, with 12 observed
transitions, towards the low-mass protostar IRAS 16293-2422, as well as
multifrequency observations of 13CH3OH, used to derive the column density of
the main isotopomer CH3OH. The derived fractionation ratio [CD3OH]/[CH3OH]
averaged on a 10'' beam is 1.4%. Together with previous CH2DOH and CHD2OH
observations, the present CD3OH observations are consistent with a formation of
methanol on grain surfaces, if the atomic D/H ratio is 0.1 to 0.3 in the
accreting gas. Such a high atomic ratio can be reached in the frame of
gas-phase chemical models including all deuterated isotopomers of H3+.Comment: Accepted by A&
Water emission in NGC1333-IRAS4: The physical structure of the envelope
We report ISO-LWS far infrared observations of CO, water and oxygen lines
towards the protobinary system IRAS4 in the NGC1333 cloud. We detected several
water, OH, CO rotational lines, and two [OI] and [CII] fine structure lines.
Given the relatively poor spectral and spatial resolution of these
observations, assessing the origin of the observed emission is not
straightforward. In this paper, we focus on the water line emission and explore
the hypothesis that it originates in the envelopes that surround the two
protostars, IRAS4 A and B, thanks to an accurate model. The model reproduces
quite well the observed water line fluxes, predicting a density profile, mass
accretion rate, central mass, and water abundance profile in agreement with
previous works. We hence conclude that the emission from the envelopes is a
viable explanation for the observed water emission, although we cannot totally
rule out the alternative that the observed water emission originates in the
outflow
Hyperentanglement of two photons in three degrees of freedom
A 6-qubit hyperentangled state has been realized by entangling two photons in
three degrees of freedom. These correspond to the polarization, the
longitudinal momentum and the indistinguishable emission produced by a
2-crystal system operating with Type I phase matching in the spontaneous
parametric down conversion regime. The state has been characterized by a
chained interferometric apparatus and its complete entangled nature has been
tested by a novel witness criterium specifically introduced for hyperentangled
states. The experiment represents the first realization of a genuine
hyperentangled state with the maximum entanglement between the two particles
allowed in the given Hilbert space.Comment: 4 pages, 2 figures, Revtex
Clearance of human papillomavirus related anal condylomas after oral and endorectal multistrain probiotic supplementation in an HIV positive male: A case report.
Abstract
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Introduction:
Here we present the case of a 56-year-old human immunodeficiency virus (HIV)-infected man with multiple anal condylomas and positivity for human papilloma virus (HPV) 18 on anal brushing. Biopsies of the anal mucosa led to the diagnosis of Bowen's disease and a subsequent pelvic magnetic resonance imaging (MRI) scan evidenced multiple reactive lymphoadenopathies and large intra-anal condylomas. The patient was treated with a complete excision of Bowen's lesion and with a 4 months course of supplementation with a high concentration multistrain probiotic formulation administered orally and by rectal instillation with the purpose to reduce local inflammation and to enhance local mucosal immunity.
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Conclusion:
An MRI performed at the end of the supplementation period evidenced the clearance of the anal condylomas previously described and no evidence of residual lymphadenopathies. Trials are therefore required to confirm this therapeutic possibility and for a better understanding of the mechanisms by which this specific probiotic formulation interacts with local epithelium when administered by the anal route
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