670 research outputs found

    Reddening, Absorption, and Decline Rate Corrections for a Complete Sample of Type Ia Supernovae leading to a Fully Corrected Hubble Diagram to v<30,000kms-1

    Full text link
    Photometric BVI and redshift data corrected for streaming motions are compiled for 111 "Branch normal", 4 1991T-like, 7 1991bg-like, and 2 unusual SNe Ia. Color excesses E(B-V)host of normal SNe Ia, due to the absorption of the host galaxy, are derived by three independent methods leading to the intrinsic colors at maximum of (B-V)00=-0.024, and (V-I)00=-0.265 if normalized to a common decline rate of Dm_15=1.1. The strong correlation between redshift absolute magnitudes (based on Ho=60), corrected only for the extrinsic Galactic absorption, and the derived E(B-V)host leads to well determined, yet abnormal absorption-to-reddening ratios of R_BVI=3.65, 2.65, and 1.35. Comparison with the canonical Galactic values of 4.1, 3.1, 1.8 forces the conclusion that the law of interstellar absorption in the path length to the SN in the host galaxy is different from the local Galactic law. Improved correlations of the fully corrected absolute magnitudes with host galaxy type, decline rate, and intrinsic color are derived. The four peculiar 1991T-type SNe are significantly overluminous as compared to Branch-normal SNe Ia. The overluminosity of the seven 1999aa-like SNe is less pronounced. The seven 1991bg-types in the sample constitute a separate class of SNeIa, averaging in B two magnitudes fainter than the normal Ia. New Hubble diagrams in BVI are derived out to ~30,000kms-1 using the fully corrected magnitudes and velocities, corrected for streaming motions. Nine solutions for the intercept magnitudes in these diagrams show extreme stability at the 0.04 level using various subsamples of the data. The same precepts for fully correcting SN magnitudes we shall use for the luminosity recalibration of SNe Ia in the forthcoming final review of our HST Cepheid-SN experiment for the Hubble constant.Comment: 49 pages, 15 figures, 8 tables, accepted for publication in the Astrophysical Journa

    Macroscopic transport by synthetic molecular machines

    Get PDF
    Nature uses molecular motors and machines in virtually every significant biological process, but demonstrating that simpler artificial structures operating through the same gross mechanisms can be interfaced with—and perform physical tasks in—the macroscopic world represents a significant hurdle for molecular nanotechnology. Here we describe a wholly synthetic molecular system that converts an external energy source (light) into biased brownian motion to transport a macroscopic cargo and do measurable work. The millimetre-scale directional transport of a liquid on a surface is achieved by using the biased brownian motion of stimuli-responsive rotaxanes (‘molecular shuttles’) to expose or conceal fluoroalkane residues and thereby modify surface tension. The collective operation of a monolayer of the molecular shuttles is sufficient to power the movement of a microlitre droplet of diiodomethane up a twelve-degree incline.

    Phthalocyanine-nanocarbon ensembles: From discrete molecular and supramolecular systems to hybrid nanomaterials

    Get PDF
    This document is the Accepted Manuscript version of a Published Work that appeared in final form in Accounts of Chemical Research, copyright © American Chemical Society after peer review and technical editing by the publisher. To access the final edited and published work see http://dx.doi.org/10.1021/ar5004384Conspectus Phthalocyanines (Pcs) are macrocyclic and aromatic compounds that present unique electronic features such as high molar absorption coefficients, rich redox chemistry, and photoinduced energy/electron transfer abilities that can be modulated as a function of the electronic character of their counterparts in donor-acceptor (D-A) ensembles. In this context, carbon nanostructures such as fullerenes, carbon nanotubes (CNTs), and, more recently, graphene are among the most suitable Pc companions. Pc-C60 ensembles have been for a long time the main actors in this field, due to the commercial availability of C60 and the ell-established synthetic methods for its functionalization. As a result, many Pc-C60 architectures have been prepared, featuring different connectivities (covalent or supramolecular), intermolecular interactions (self-organized or molecularly dispersed species), and Pc HOMO/LUMO levels. All these elements provide a versatile toolbox for tuning the photophysical properties in terms of the type of process (photoinduced energy/electron transfer), the nature of the interactions beteen the electroactive units (through bond or space), and the kinetics of the formation/decay of the photogenerated species. Some recent trends in this field include the preparation of stimuli-responsive multicomponent systems ith tunable photophysical properties and highly ordered nanoarchitectures and surface-supported systems shoing high charge mobilities. A breakthrough in the Pc-nanocarbon field as the appearance of CNTs and graphene, hich opened a ne avenue for the preparation of intriguing photoresponsive hybrid ensembles shoing light-stimulated charge separation. The scarce solubility of these 1-D and 2-D nanocarbons, together ith their loer reactivity ith respect to C60 stemming from their less strained sp2 carbon netorks, has not meant an unsurmountable limitation for the preparation of variety of Pc-based hybrids. These systems, hich sho improved solubility and dispersibility features, bring together the unique electronic transport properties of CNTs and graphene ith the excellent light-harvesting and tunable redox properties of Pcs. A singular and distinctive feature of these Pc-CNT/graphene (single- or fe-layers) hybrid materials is the control of the direction of the photoinduced charge transfer as a result of the band-like electronic structure of these carbon nanoforms and the adjustable electronic levels of Pcs. Moreover, these conjugates present intensified light-harvesting capabilities resulting from the grafting of several chromophores on the same nanocarbon platform.In this Account, recent progress in the construction of covalent and supramolecular Pc-nanocarbon ensembles is summarized, ith a particular emphasis on their photoinduced behavior. e believe that the high degree of control achieved in the preparation of Pc-carbon nanostructures, together ith the increasing knoledge of the factors governing their photophysics, ill allo for the design of next-generation light-fueled electroactive systems. Possible implementation of these Pc-nanocarbons in high performance devices is envisioned, finally turning into reality much of the expectations generated by these materialsFinancial support from the Spanish MICINN (CTQ2011-24187/BQU), the Comunidad de Madrid (S2013/MIT-2841 FOTOCARBON) and the EU (“SO2S” FP7-PEOPLE-2012-ITN, no.: 316975) is acknowledge

    Novel insights on pink discoloration in cheese: The case of Pecorino Toscano

    Get PDF
    Pink discoloration in cheese has been the subject of wide research, but the basis for this phenomenon remains elusive. This defect impacts a wide range of ripened cheeses, resulting in the rejection of cheese and a consequent economic loss for dairy industries. As multiple causes for pink discoloration have been reported for different cheeses in the literature, the aim of this research was to investigate the cause of a pink discoloration found on Pecorino Toscano cheese rind. The results of microbiological analysis revealed the presence of high microbial counts associated to the rind and the nearest inner part. Strains isolated from the coloured part were mainly identified as Serratia liquefaciens, suggesting that an environmental contamination of the cheese rind by this species could be the cause of the observed defect and expanding the knowledge related to pink discoloration in cheeses

    Combination antiretroviral therapy and the risk of myocardial infarction

    Get PDF

    Wild Lactobacillus casei Group Strains: Potentiality to Ferment Plant Derived Juices

    Get PDF
    Plant derived beverages have recently gained consumers’ interest, particularly due to their intrinsic functional properties. They can also act as non-dairy carriers for probiotics and prebiotics, meeting the needs of lactose allergic/intolerant people and vegans. Direct fermentation of fruit and vegetables juices by probiotic lactic acid bacteria could be a tool to increase safety, shelf-life, nutrients bioavailability and to improve sensorial features of plant derived juices. This study aims to screen wild Lactobacillus casei-group strains isolated from dairy matrices for probiotic features, such as acid and bile salts resistance, and test them for the potentiality to ferment celery and orange juices. Strains’ ability to produce exopolysaccharides (EPS) in situ is also checked. These evaluations were performed for the first time in fruit and vegetables matrices by means of an impedometric analysis, recently shown to be a suitable and rapid method to measure microorganisms’ growth, acidification performances and EPS production. This study allowed the selection of three potentially probiotic L. casei-group wild strains able to ferment fruit and vegetable juices and also producing EPS. These strains with three-in-one abilities could be used to produce new functional fermented plant derived juices

    Interacting Preformed Cooper Pairs in Resonant Fermi Gases

    Get PDF
    We consider the normal phase of a strongly interacting Fermi gas, which can have either an equal or an unequal number of atoms in its two accessible spin states. Due to the unitarity-limited attractive interaction between particles with different spin, noncondensed Cooper pairs are formed. The starting point in treating preformed pairs is the Nozi\`{e}res-Schmitt-Rink (NSR) theory, which approximates the pairs as being noninteracting. Here, we consider the effects of the interactions between the Cooper pairs in a Wilsonian renormalization-group scheme. Starting from the exact bosonic action for the pairs, we calculate the Cooper-pair self-energy by combining the NSR formalism with the Wilsonian approach. We compare our findings with the recent experiments by Harikoshi {\it et al.} [Science {\bf 327}, 442 (2010)] and Nascimb\`{e}ne {\it et al.} [Nature {\bf 463}, 1057 (2010)], and find very good agreement. We also make predictions for the population-imbalanced case, that can be tested in experiments.Comment: 10 pages, 6 figures, accepted version for PRA, discussion of the imbalanced Fermi gas added, new figure and references adde

    Does congenital deafness affect the structural and functional architecture of primary visual cortex?

    Get PDF
    Deafness results in greater reliance on the remaining senses. It is unknown whether the cortical architecture of the intact senses is optimized to compensate for lost input. Here we performed widefield population receptive field (pRF) mapping of primary visual cortex (V1) with functional magnetic resonance imaging (fMRI) in hearing and congenitally deaf participants, all of whom had learnt sign language after the age of 10 years. We found larger pRFs encoding the peripheral visual field of deaf compared to hearing participants. This was likely driven by larger facilitatory center zones of the pRF profile concentrated in the near and far periphery in the deaf group. pRF density was comparable between groups, indicating pRFs overlapped more in the deaf group. This could suggest that a coarse coding strategy underlies enhanced peripheral visual skills in deaf people. Cortical thickness was also decreased in V1 in the deaf group. These findings suggest deafness causes structural and functional plasticity at the earliest stages of visual cortex

    Game accessibility for visually impaired people: a review

    Get PDF
    Playing games is an important way to promote the integration, inclusion, and socialization of participants. This is especially the case of persons with disabilities, such as visually impaired people. Unfortunately, very few games are accessible to such persons. Hopefully, in many digital games, this accessibility can be enabled in principle by assistive technologies, such as screen readers. The aim of this work consists in reviewing the recent literature on game accessibility for people with visual impairment and discussing benefits, limitations, and possible improvements of currently available accessibility solutions. After providing a definition of visual impairment and describing its relationship with gaming, the work reviews general techniques for designing more accessible games. Subsequently, it focuses on specific techniques based on replacing visual stimuli with auditory stimuli (e.g., sonification and sound-source simulation), also presenting some recently proposed sonification-mapping strategies. Then, the application of machine-learning techniques to the development of accessible interfaces for online versions of board games is illustrated by a recent case study. Finally, a discussion and some conclusions are provided, with a particular focus on policy implications of improvements in game accessibility for visually impaired people

    Eating fermented: Health benefits of lab-fermented foods

    Get PDF
    Lactic acid bacteria (LAB) are involved in producing a considerable number of fermented products consumed worldwide. Many of those LAB fermented foods are recognized as beneficial for human health due to probiotic LAB or their metabolites produced during food fermentation or after food digestion. In this review, we aim to gather and discuss available information on the health-related effects of LAB-fermented foods. In particular, we focused on the most widely consumed LAB-fermented foods such as yoghurt, kefir, cheese, and plant-based products such as sauerkrauts and kimchi
    corecore