2,270 research outputs found
Museum Websites of the First Wave: The rise of the virtual museum
In this paper, we analyse trends of the first wave of museum websites (from the 1990s to the early 2000s) to understand how the characteristics of the Internet (specifically the World Wide Web), of museum staff, and museum audiences shaped the adoption of technology and new forms of participation and what they can tell us about engagement for museums of the future. The early development of online museum resources parallels the development of the EVA conference, which was establishing itself at a similar time
The merger that led to the formation of the Milky Way's inner stellar halo and thick disk
The assembly process of our Galaxy can be retrieved using the motions and
chemistry of individual stars. Chemo-dynamical studies of the nearby halo have
long hinted at the presence of multiple components such as streams, clumps,
duality and correlations between the stars' chemical abundances and orbital
parameters. More recently, the analysis of two large stellar surveys have
revealed the presence of a well-populated chemical elemental abundance
sequence, of two distinct sequences in the colour-magnitude diagram, and of a
prominent slightly retrograde kinematic structure all in the nearby halo, which
may trace an important accretion event experienced by the Galaxy. Here report
an analysis of the kinematics, chemistry, age and spatial distribution of stars
in a relatively large volume around the Sun that are mainly linked to two major
Galactic components, the thick disk and the stellar halo. We demonstrate that
the inner halo is dominated by debris from an object which at infall was
slightly more massive than the Small Magellanic Cloud, and which we refer to as
Gaia-Enceladus. The stars originating in Gaia-Enceladus cover nearly the full
sky, their motions reveal the presence of streams and slightly retrograde and
elongated trajectories. Hundreds of RR Lyrae stars and thirteen globular
clusters following a consistent age-metallicity relation can be associated to
Gaia-Enceladus on the basis of their orbits. With an estimated 4:1 mass-ratio,
the merger with Gaia-Enceladus must have led to the dynamical heating of the
precursor of the Galactic thick disk and therefore contributed to the formation
of this component approximately 10 Gyr ago. These findings are in line with
simulations of galaxy formation, which predict that the inner stellar halo
should be dominated by debris from just a few massive progenitors.Comment: 19 pages, 8 figures. Published in Nature in the issue of Nov. 1st,
2018. This is the authors' version before final edit
Joint estimation of phase and phase diffusion for quantum metrology
Phase estimation, at the heart of many quantum metrology and communication
schemes, can be strongly affected by noise, whose amplitude may not be known,
or might be subject to drift. Here, we investigate the joint estimation of a
phase shift and the amplitude of phase diffusion, at the quantum limit. For
several relevant instances, this multiparameter estimation problem can be
effectively reshaped as a two-dimensional Hilbert space model, encompassing the
description of an interferometer phase probed with relevant quantum states --
split single-photons, coherent states or N00N states. For these cases, we
obtain a trade-off bound on the statistical variances for the joint estimation
of phase and phase diffusion, as well as optimum measurement schemes. We use
this bound to quantify the effectiveness of an actual experimental setup for
joint parameter estimation for polarimetry. We conclude by discussing the form
of the trade-off relations for more general states and measurements.Comment: Published in Nature Communications. Supplementary Information
available at
http://www.nature.com/ncomms/2014/140404/ncomms4532/extref/ncomms4532-s1.pd
Cognitive Based Design of a HMI for Telenavigation of A Space Rover
Human Machine Interface (HMI) design is a critical field of work because no general guidelines or rules have been assessed. In order to aid practitioners to design effective HMIs, different methodologies have been studied. To understand task objectives and plan goal-oriented actions, human operators exploit specific cognitive processes that have to be supported with advanced interfaces. Including cognitive aspects in HMI design allows generating an information flow that reduces user mental workload, increasing his/her situation awareness. This paper focuses on design and test of aGraphical User Interface (GUI) for the telenavigation of a space rover that makes the cognitive process of the user a priority in relation to the other development guidelines. To achieve this, a Cognitive Task Analysis (CTA) techinque, known as Applied Cognitive Work Analysis (ACWA), is combined with a multi-agent empirical test to ensure the GUI effectiveness. The ACWA allows evaluating mission scenarios, i.e. piloting the rover on the Mars surface, in order to obtain a model of the human cognitive demands that arise in these complex work domains. These demands can be used to obtain an effective information flow between the GUI and the operator. The multi-agent empirical test, on the other hand, allows an early feedback on the user mental workload aiming to validate the GUI. The result of the methodology is a GUI that eases the information flow through the interface, enhancing operator’s performance
Usability, Design and Content Issues of Mobile Apps for Cultural Heritage Promotion: The Malta Culture Guide Experience
The paper discusses the experience of producing and distributing an iPhone app for promotion of the Maltese Cultural Heritage on behalf of the Malta Tourism Authority. Thanks to its position at the heart of the Mediterranean Sea, Malta has been a crossroads of civilisations whose traces are still visible today, leaving a particularly rich and varied cultural heritage, from megalithic temples to baroque palaces and Caravaggio masterpieces. Conveying all these different aspects within a single application, using textual, visual, and audio means, has raised many different issues about the planning and production of cultural content for mobile usage, together with usability aspects regarding design and distribution of a mobile app. In this paper, we outline all of these aspects, focusing on the design and planning strategies for a long-term user commitment and how to evaluate results for cultural mobile applications. We include experience of all the steps of developing a mobile app, information that is of possible benefit to other app developers in the cultural sector
Protocolo de eletroforese de isoenzimas de cupuaçu em gel de poliacrilamida.
bitstream/item/57719/1/CPATU-PA211.pd
Production of benzaldehyde, benzyl alcohol and benzoic acid by yeasts and Botrytis cinerea isolated from grape musts and wines
The capacity of 100 yeast strains - isolated from grape musts and wines from the Istituto Sperimentale per l'Enologia collection - to produce benzaldehyde, benzyl alcohol and benzoic acid was verified by inoculation into a synthetic nutrient medium (MNS). Schizosaccharomyces and Zygosaccharomyces were strongest in producing benzaldehyde (maximal amount found 1200 µg/l) and benzyl alcohol (maximally 523 µg/l). Zygosaccharomyces was also most effective in the production of benzoic acid (maximally 536 µg/l), followed by Saccharomyces, Cryptococcus, Kloeckera and Torulaspora. The hypothesis was verified that yeasts can be an exogenous source of the benzyl alcohol oxidizing enzyme in grape musts and wines. Wine yeast strains of Saccharomyces spp., Zygosaccharomyces spp. and Schizosaccharomyces spp. fermenting MNS containing 150 g/l glucose, with benzyl alcohol added, transformed this into benzoic acid only when glucose was disappearing, but not into benzaldehyde. No difference was observed between aerobic and anaerobic fermentation conditions. The uptake of benzyl alcohol was rapid in fermentation essays in presence of only 10 g/l glucose and in assimilation essais performed in yeast nitrogen base broth with assimilable carbon compounds added. A catabolic repression by glucose appears likely. Botrytis cinerea was able to transform benzyl alcohol into benzaldehyde and benzoic acid on Czapek-Dox broth with 30 g/l sucrose added. Benzyl alcohol was transformed by wine yeasts into benzoic acid when the concentration of glucose in the mineral medium was less than 10 g/l, but no production of benzaldehyde was observed. A catabolic repression of this transformation by glucose is likely. Botrytis cinerea was able to produce benzaldehyde in a mineral medium with benzyl alcohol and sucrose added
Observational Hertzsprung-Russell diagrams
Context. Gaia Data Release 2 provides high-precision astrometry and three-band photometry for about 1.3 billion sources over the full sky. The precision, accuracy, and homogeneity of both astrometry and photometry are unprecedented. Aims. We highlight the power of the Gaia DR2 in studying many fine structures of the Hertzsprung-Russell diagram (HRD). Gaia allows us to present many different HRDs, depending in particular on stellar population selections. We do not aim here for completeness in terms of types of stars or stellar evolutionary aspects. Instead, we have chosen several illustrative examples. Methods. We describe some of the selections that can be made in Gaia DR2 to highlight the main structures of the Gaia HRDs. We select both field and cluster (open and globular) stars, compare the observations with previous classifications and with stellar evolutionary tracks, and we present variations of the Gaia HRD with age, metallicity, and kinematics. Late stages of stellar evolution such as hot subdwarfs, post-AGB stars, planetary nebulae, and white dwarfs are also analysed, as well as low-mass brown dwarf objects. Results. The Gaia HRDs are unprecedented in both precision and coverage of the various Milky Way stellar populations and stellar evolutionary phases. Many fine structures of the HRDs are presented. The clear split of the white dwarf sequence into hydrogen and helium white dwarfs is presented for the first time in an HRD. The relation between kinematics and the HRD is nicely illustrated. Two different populations in a classical kinematic selection of the halo are unambiguously identified in the HRD. Membership and mean parameters for a selected list of open clusters are provided. They allow drawing very detailed cluster sequences, highlighting fine structures, and providing extremely precise empirical isochrones that will lead to more insight in stellar physics. Conclusions. Gaia DR2 demonstrates the potential of combining precise astrometry and photometry for large samples for studies in stellar evolution and stellar population and opens an entire new area for HRD-based studies.Peer reviewe
MamĂferos encontrados ao Sul do Estado do Acre, Brasil.
Entre os anos de 2004 e 2008, sete inventários de mamĂferos foram realizados em quatro áreas sob manejo florestal madeireiro e nĂŁo madeireiro localizadas ao sul do Estado do Acre. A partir de transectos lineares instalados nas áreas, foi possĂvel identificar 32 espĂ©cies pertencentes Ă s ordens Artiodactyla, Perissodactyla, Carnivora, Primates, Rodentia e Xenarthra, que incluĂram as espĂ©cies ameaçadas de extinção, de distribuição geográfica restrita ou pouco conhecidas. Entre os animais observados destaca-se a predominância dos primatas nas quatro áreas estudadas. Nesse caso, especula-se sobre a possibilidade desse grupo taxonĂ´mico ser utilizado como bioindicador da qualidade ambiental das áreas de manejo florestal no Estado do Acre.bitstream/item/77684/1/boletim-de-pesquisa-48.pd
Development of NASH in Obese Mice is Confounded by Adipose Tissue Increase in Inflammatory NOV and Oxidative Stress
Aim. Nonalcoholic steatohepatitis (NASH) is the consequence of insulin resistance, fatty acid accumulation, oxidative stress, and
lipotoxicity.We hypothesize that an increase in the inflammatory adipokine NOV decreases antioxidant Heme Oxygenase 1 (HO-
1) levels in adipose and hepatic tissue, resulting in the development of NASH in obese mice. Methods. Mice were fed a high
fat diet (HFD) and obese animals were administered an HO-1 inducer with or without an inhibitor of HO activity to examine
levels of adipose-derived NOV and possible links between increased synthesis of inflammatory adipokines and hepatic pathology.
Results. NASH mice displayed decreased HO-1 levels and HO activity, increased levels of hepatic heme, NOV, MMP2, hepcidin,
and increased NAS scores and hepatic fibrosis. IncreasedHO-1 levels are associated with a decrease in NOV, improved hepatic NAS
score, ameliorated fibrosis, and increases in mitochondrial integrity and insulin receptor phosphorylation. Adipose tissue function
is disrupted in obesity as evidenced by an increase in proinflammatory molecules such as NOV and a decrease in adiponectin.
Importantly, increased HO-1 levels are associated with a decrease of NOV, increased adiponectin levels, and increased levels of
thermogenic and mitochondrial signaling associated genes in adipose tissue. Conclusions.These results suggest that the metabolic
abnormalities in NASH are driven by decreased levels of hepatic HO-1 that is associated with an increase in the adipose-derived
proinflammatory adipokine NOV in our obese mouse model of NASH. Concurrently, induction of HO-1 provides protection
against insulin resistance as seen by increased insulin receptor phosphorylation. Pharmacological increases in HO-1 associated
with decreases in NOV may offer a potential therapeutic approach in preventing fibrosis, mitochondrial dysfunction, and the
development of NASH
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