1,986 research outputs found
Quantum chaos in the mesoscopic device for the Josephson flux qubit
We show that the three-junction SQUID device designed for the Josephson flux
qubit can be used to study quantum chaos when operated at high energies. In the
parameter region where the system is classically chaotic we analyze the
spectral statistics. The nearest neighbor distributions are well fitted
by the Berry Robnik theory employing as free parameters the pure classical
measures of the chaotic and regular regions of phase space in the different
energy regions. The phase space representation of the wave functions is
obtained via the Husimi distributions and the localization of the states on
classical structures is analyzed.Comment: Final version, to be published in Phys. Rev. B. References added,
introduction and conclusions improve
Shear-induced fractures and three-dimensional motions in an organogel
The flow behavior of a viscoelastic organogel is investigated using
ultrasonic velocimetry combined with rheometry. Our gel presents a decreasing
flow curve, i.e., the measured stress decreases as a function of the applied
shear rate. Strikingly, we note that the local flow curve calculated from the
velocity profiles also exhibits a decreasing part. We attribute this regime to
the presence of a fracturing process and three-dimensional motions in the bulk
of the sample.Comment: 13 pages, 19 figure
Micelles by self-assembling peptide-conjugate amphiphile: synthesis and structural characterization.
The solid-phase synthesis of a novel amphiphilic peptide conjugate I, contg. in the same mol. three different functions: N,N-bis[2-[bis(carboxyethyl)amino]ethyl]-L-glutamic acid chelating agent, the CCK8 bioactive peptide, and a hydrophobic moiety contg. four alkyl chains with 18 carbon atoms each, is reported. In water soln. at pH 7.4, I self-assembles in very stable micelles at very low concn. [crit. micellar concn. (cmc) values of 5 10-7 mol kg-1] as confirmed by fluorescence spectroscopy. The structural characterization, obtained with small-angle neutron scattering (SANS) measurements, indicates that the aggregates are substantially represented by ellipsoidal micelles with an aggregation no. of 39 2 and the two micellar axes of about 52 and 26
The Dynamics of the Innovation System for Functional Foods in South Brazil
This study aims at identifying the dynamics of the innovation system for functional foods (FF) in Rio Grande do Sul, Brazil. Functional food is any healthy food claimed to have a health-promoting or disease-preventing property beyond the basic function of supplying nutrients. Health has been named as the most significant trend and innovation driver in the global food and drinks market. Brazil is one of the leading countries in food production and consumption, and the market for functional foods have been growing 10% per year, three times more than the market for conventional foods. Although this food category is considered mature in some developed markets (such as in Japan, in the Nordic countries and in the U.S), it is still unknown for many consumers, especially those located in developing countries. On the other hand, functional foods has been attracting the attention of multinationals and local food industries, since innovation can significantly impact on their competitive advantages. Therefore, in this study, first we are going to investigate consumers’ motivations, attitudes and intention to buy functional foods, since the market demands a better understanding of this trend. A survey with 450 consumers was conducted and provided quantitative insights. Secondly, we identified the availability of functional food products in the local retail market, through observation techniques. Our aim was to confront consumers’ needs with local food companies’ market supply. In a further stage, we are going to analyse the functioning of this innovation system, describing the agents involved in this context and their relations through in-depth interviews with local representatives (stakeholders). Innovation system is here understood as the set of distinct institutions which jointly and individually contribute to the development and diffusion of new technologies and which provides the framework within which governments form and implement policies to influence the innovation process. As such "it is a system of interconnected institutions to create, store and transfer the knowledge, skills and artefacts which define new technologies." (Metcalfe, 1995). Hence, we are investigating issues such as: Are local food companies ready to innovate in such a competitive and dynamic scenario? How can this system respond to consumers’ demands? Are there conditions for an innovative food network in South Brazil? Our contributions help to shed light into these questions. Preliminary results indicate that the innovation system for functional foods in Rio Grande do Sul is incipient, but it is developing fast. Stronger governance and co-ordination strategies are needed. There are few local functional food products in the market, but those are attractive to consumers and indicate promising opportunities. The survey shows that interviewed consumers presented positive attitudes towards functional foods and enough purchasing power to buy it. Nutritionists and other health professionals have high credibility and could help inform consumers about the benefits of particular categories of functional foods. Food industry itself is not regarded as the most trustworthy source. Finally, this study shows that the understanding of Brazilian consumers is fundamental to help food companies define their strategies. To map the most accepted categories of functional foods is also important, aiming to avoid the "tentative and error" approach
Testing general relativity using golden black-hole binaries
The coalescences of stellar-mass black-hole binaries through their inspiral,
merger, and ringdown are among the most promising sources for ground-based
gravitational-wave (GW) detectors. If a GW signal is observed with sufficient
signal-to-noise ratio, the masses and spins of the black holes can be estimated
from just the inspiral part of the signal. Using these estimates of the initial
parameters of the binary, the mass and spin of the final black hole can be
uniquely predicted making use of general-relativistic numerical simulations. In
addition, the mass and spin of the final black hole can be independently
estimated from the merger--ringdown part of the signal. If the binary black
hole dynamics is correctly described by general relativity (GR), these
independent estimates have to be consistent with each other. We present a
Bayesian implementation of such a test of general relativity, which allows us
to combine the constraints from multiple observations. Using kludge modified GR
waveforms, we demonstrate that this test can detect sufficiently large
deviations from GR, and outline the expected constraints from upcoming GW
observations using the second-generation of ground-based GW detectors.Comment: 5 pages, 2 fig
A new <sup>68</sup>Ga-labeled somatostatin analog containing two iodo-amino acids for dual somatostatin receptor subtype 2 and 5 targeting.
Somatostatin receptor (SST) targeting, specifically of the subtype 2 (SST2), with radiolabeled somatostatin analogs, is established for imaging and treatment of neuroendocrine tumors. Owing to the concomitant and heterogeneous expression of several subtypes on the same tumor, analogs targeting more subtypes than SST2 potentially target a broader spectrum of tumors and/or increase the uptake of a given tumor. The analog ST8950 ((4-amino-3-iodo)-D-Phe-c[Cys-(3-iodo)-Tyr-D-Trp-Lys-Val-Cys]-Thr-NH <sub>2</sub> ), bearing 2 iodo-amino acids, exhibits sub-nanomolar affinity to SST2 and SST5. We report herein the development and preclinical evaluation of DOTA-ST8950 labeled with <sup>68</sup> Ga, for imaging SST2- and SST5-expressing tumors. Comparative in vitro and in vivo studies were performed with the de-iodinated DOTA-ST8951 ((4-amino)-D-Phe-c[Cys-Tyr-D-Trp-Lys-Val-Cys]-Thr-NH <sub>2</sub> ) and with the reference compounds DOTA-TATE (SST2 selective) and DOTA-NOC (for SST2 and SST5).
Compared with <sup>nat</sup> Ga-DOTA-NOC, <sup>nat</sup> Ga-DOTA-ST8950 exhibited higher affinity to SST2 and SST5 (IC <sub>50</sub> (95%CI), nM = 0.32 (0.20-0.50) and 1.9 (1.1-3.1) vs 0.70 (0.50-0.96) and 3.4 (1.8-6.2), respectively), while <sup>nat</sup> Ga-DOTA-ST8951 lost affinity for both subtypes. <sup>nat</sup> Ga-DOTA-ST8950 had the same potency for inducing SST2-mediated cAMP accumulation as <sup>nat</sup> Ga-DOTA-TATE and slightly better than <sup>nat</sup> Ga-DOTA-NOC (EC <sub>50</sub> , nM = 0.46 (0.23-0.92) vs 0.47 (0.15-1.5) vs 0.59 (0.18-1.9), respectively). [ <sup>67</sup> Ga]Ga-DOTA-ST8950 had a similar internalization rate as [ <sup>67</sup> Ga]Ga-DOTA-NOC in SST2-expressing cells (12.4 ± 1.6% vs 16.6 ± 2.2%, at 4 h, p = 0.0586). In vivo, [ <sup>68</sup> Ga]Ga-DOTA-ST8950 showed high and specific accumulation in SST2- and SST5-expressing tumors, comparable with [ <sup>68</sup> Ga]Ga-DOTA-NOC (26 ± 8 vs 30 ± 8 %IA/g, p = 0.4630 for SST2 and 15 ± 6 vs 12 ± 5 %IA/g, p = 0.3282, for SST5, 1 h p.i.) and accumulation in the SST-positive tissues, the kidneys and the liver. PET/CT images of [ <sup>68</sup> Ga]Ga-DOTA-ST8950, performed in a dual HEK-SST2 and HEK-SST5 tumor xenografted model, clearly visualized both tumors and illustrated high tumor-to-background contrast.
[ <sup>68</sup> Ga]Ga-DOTA-ST8950 reveals its potential for PET imaging SST2- and SST5-expressing tumors. It compares favorably with the clinically used [ <sup>68</sup> Ga]Ga-DOTA-NOC in terms of tumor uptake; however, its uptake in the liver remains a challenge for clinical translation. In addition, this study reveals the essential role of the iodo-substitutions in positions 1 and 3 of [ <sup>68</sup> Ga]Ga-DOTA-ST8950 for maintaining affinity to SST2 and SST5, as the de-iodinated [ <sup>68</sup> Ga]Ga-DOTA-ST8951 lost affinity for both receptor subtypes
La teoría y los procedimientos de su construcción: Una experiencia en Física e Historia
Gelatin-based coating enriched with blueberry juice preserves the nutraceutical quality and reduces the microbial contamination of tomato fruit
To preserve quality and extend the shelf life of tomato, a bioactive edible coating was prepared using gelatin wastes from pharmaceutical industry and lyophilised blueberry juice (BJ). The effectiveness of gelatin-coating (G) and G enriched with blueberry juice (GB) was tested, monitoring carotenoids, polyphenols and flavonoids content, the antioxidant activity and the antimicrobial efficiency of coating against the native microflora. After 7 d of storage, coated fruit showed higher phenolic and flavonoids content and increased antioxidant activity, while carotenoids were unaffected by the treatments. The growth of mesophilic bacteria of GB, and the growth of coliform bacteria of G and GB were significantly reduced during the entire period. The results indicate that GB preserved the nutritional quality of tomatoes and that BJ was able to increase the antimicrobial activity of the coating. This paves the way for a possible use of this biodegradable waste polymer as an eco-friendly coating material
Carers' perceptions of harm and the protective measures taken to safeguard children's health against inhalation of volcanic ash: A comparative study across Indonesia, Japan and Mexico
Volcanic ash contains potentially toxic elements which could affect human health. There is a paucity of research focusing on the impact of airborne volcanic emissions on the health of children, and on their exposure reduction. Children's carers (parents/guardians) are critical to their protection, so documenting their perceptions of the health risk and their knowledge of how to reduce their children's exposure is an important first step to increase our understanding of how risks are acted upon. This article reports the findings of a survey of 411 residents with caring responsibilities for children aged 12 and under in communities near the active volcanoes of Sakurajima in Japan, Merapi in Indonesia, and Popocatépetl in Mexico. Informed by the Protective Action Decision Model (PADM) and Protection Motivation Theory (PMT), we investigated their perceptions of the health effects and harmful consequences of the ash on their children, how important they thought it was to protect them, and the protective actions taken. The Indonesian carers were the most concerned and motivated to protect their children, although, in all three countries, the large majority of carers had adopted protective measures that they perceived to be most effective, such as keeping windows and doors closed. Path analysis illustrated how the connection between perceptions of harm/worry and importance of protection could partially account for higher motivation levels to protect children, in the Indonesian carers. We discuss the key messages conveyed through the findings that are of relevance for policy, practice and training in all three countries
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