Coupled quintessence and vacuum decay

We discuss observational consequences of a class of cosmological models characterized by the dilution of pressureless matter attenuated with respect to the usual $a^{-3}$ scaling due to the decay of vacuum energy. We carry out a joint statistical analysis of observational data from the new \emph{gold} sample of 182 SNe Ia, recent estimates of the CMB shift parameter, and BAO measurements from the SDSS to show that such models favor the decay of vacuum only into the dark matter sector, and that the separately conserved baryons cannot be neglected. In order to explore ways to more fundamentally motivated models, we also derive a coupled scalar field version for this general class of vacuum decay scenarios.Comment: 6 pages, 3 figures, LaTe

Alimentação na seca: cana-de-açúcar e uréia.

bitstream/item/65407/1/COT-40-Alimentacao-na-seca.pd

Fabrication of zinc oxide and nanostructured porous silicon composite micropatterns on silicon

The luminescent properties of zinc oxide (ZnO) and nanostructured porous silicon (PSi) make these materials very appealing for photoemission applications. The current study reports on the fabrication of a composite of ZnO and nanostructured porous silicon micropatterns (ZnO + PSi micropatterns) onto heavily-doped silicon surfaces. The proposed composite micropattern is devoted to the future development of light-emitting diodes. The fabrication of the ZnO + PSi micropatterns was carried out in a two–step process. (1) A regular hexagonal micropattern of a photoresist/ZnO stack was fabricated by UV lithography on crystalline silicon substrates. (2) Before being lifted off the photoresist, nanostructured PSi micropatterns were fabricated by electrochemically etching the exposed areas of the silicon substrate. Subsequently, wet etching of the photoresist was carried out for the final development of the composite ZnO and PSi micropatterns. Further, thin films of ZnO and nanostructured PSi layers were characterized. In particular, their photoluminescent properties were analyzed, as well as their morphology and composition. The experimental PL results show that the ZnO layers have emission broadbands centered at (2.63 eV, blue), while the PSi layers show a band centered at (1.71 eV, red). Further, the emission peaks from the PSi layers can be tuned by changing their fabrication conditions. It was observed that the properties of the ZnO thin films are not influenced by either the surface morphology of PSi or by its PL emissions. Therefore, the PL properties of the composite ZnO + PSi micropatterns are equivalent to those featuring the addition of PSi layers and ZnO thin films. Accordingly, broadband optical emissions are expected to arise from a combination between the ZnO layer (blue band) and PSi (red band). Furthermore, the electrical losses associated with the PSi areas can be greatly reduced since ZnO is in contact with the Si surface. As a result, the proposed composite micropatterns might be attractive for many solid-state lighting applications, such as light-emitting diodesThis research was partially funded by Universidad Autónoma de Madrid, FPI-UAM grant (2019) and by the Egyptian Ministry of Higher Education, Missions Section under Egyptian Joint Supervision Grant, call 015/01

Transient dynamics for sequence processing neural networks: effect of degree distributions

We derive a analytic evolution equation for overlap parameters including the effect of degree distribution on the transient dynamics of sequence processing neural networks. In the special case of globally coupled networks, the precisely retrieved critical loading ratio $\alpha_c = N ^{-1/2}$ is obtained, where $N$ is the network size. In the presence of random networks, our theoretical predictions agree quantitatively with the numerical experiments for delta, binomial, and power-law degree distributions.Comment: 11 pages, 6 figure

Brand logo design: examining consumer responses to figurativeness

In a previous investigation, aimed at studying brand identity preferences in a merger context, researchers found the most preferred logos are figurative ones. Additionally, results suggested the aesthetic appeal of the logo significantly influences consumers’ identity choices. These results find support in logo strategy literature. The main purpose of this study is to investigate more thoroughly the influence of logo design characteristics, and particularly of figurativeness, on consumers’ responses. In two studies, this research will try to shed light on consumer logo preferences, by investigating psychological properties of figurativeness. Firstly, this research will allow classifying a significant sample of international logos according to the figurativeness of logo design. Then, this study will evaluate affect towards logo design.info:eu-repo/semantics/publishedVersio

The Critical Coupling Likelihood Method: A new approach for seamless integration of environmental and operating conditions of gravitational wave detectors into gravitational wave searches

Any search effort for gravitational waves (GW) using interferometric detectors like LIGO needs to be able to identify if and when noise is coupling into the detector's output signal. The Critical Coupling Likelihood (CCL) method has been developed to characterize potential noise coupling and in the future aid GW search efforts. By testing two hypotheses about pairs of channels, CCL is able to identify undesirable coupled instrumental noise from potential GW candidates. Our preliminary results show that CCL can associate up to $\sim 80$ of observed artifacts with $SNR \geq 8$, to local noise sources, while reducing the duty cycle of the instrument by $\lesssim 15$. An approach like CCL will become increasingly important as GW research moves into the Advanced LIGO era, going from the first GW detection to GW astronomy.Comment: submitted CQ

Prevalence and Determinants of Bullying Among Health Care Workers in Portugal

Bullying is defined as systematic exposure to humiliation as well as hostile and violent behaviors against one or more individuals. These behaviors are a serious, growing problem, which affects a significant proportion of health care professionals. To support the hospital’s risk management policy, a cross-sectional study was undertaken to determine the prevalence of bullying in this institution and identify the determinants of bullying. Bullying was measured using the Negative Acts Questionnaire–Revised, Portuguese version (NAQ-R), a self-administered tool. The questionnaire was made available in digital format on the hospital’s internal network (Intranet) and in hard copy; questionnaires were returned via nonidentified internal mail addressed to the occupational health unit or deposited in suggestion boxes located throughout the hospital. Multiple questionnaire delivery methods guaranteed data anonymity and confidentiality. The prevalence of bullying in this hospital was 8% (95% confidence interval [CI] = [6.2, 10.2]). Reported bullying was predominantly vertical and more frequently occurring among nurses, clerical staff, and health care assistants (12.5%, 7.6%, 6.4%, respectively; p = .005). After adjusting for gender, age, occupation, type of contract, and work schedule, only type of contract was significantly associated with bullying in the workplace; the risk of bullying was twice as high among government employees compared to workers with indefinite duration employment contracts (p = .038). This study identified a high prevalence of bullying among health professionals; hence a program to prevent and control this phenomenon was implemented in this institution

Sobolev homeomorphisms are dense in volume preserving automorphisms

In this paper we prove a Lusin theorem for the space of Sobolev-(1,p) volume preserving homeomorphism on closed and connected n-dimensional manifolds, n >= 3, for pn this result is not true.The authors would like to thank the anonymous referee for the careful reading of the manuscript and for giving very helpful comments and suggestions. AA and MJT were partially supported by the Research Centre of Mathematics of the University of Minho with the Portuguese Funds from the “Fundação para a Ciência e a Tecnologia”, through the Project UID/MAT/ 00013/2013. MB was partially supported by FCT - ‘Fundação para a Ciência e a Tecnologia’, through Centro de Matemática e Aplicações (CMA-UBI), Universidade da Beira Interior, project UID/MAT/00212/2013

Randomized Clinical Trial of Balloon Occlusion versus Conventional Microcatheter Prostatic Artery Embolization for Benign Prostatic Hyperplasia

Purpose: To compare balloon occlusion prostatic artery embolization (bPAE) with conventional microcatheter PAE (cPAE). Materials and methods: In this single-center trial, between November 2017 and November 2018, 89 patients with symptomatic benign prostatic hyperplasia were randomly assigned to cPAE (n = 43) or bPAE (n = 46). All patients received embolization with 300-500 μm Embosphere microspheres and were evaluated before and 1 and 6 months after PAE. Primary outcome measure was change from baseline in International Prostate Symptom Score (IPSS). Student t test was used for between-group comparisons of change from baseline, and paired t test was used for within-group comparisons. Results: At baseline, groups were identical (P > .05). Unilateral PAE was performed in 4 patients receiving cPAE and 3 patients receiving bPAE (9.30% and 6.52%, P = .708). Procedural and fluoroscopy times, dose area product, air kerma, embolic volume, and mean prostate-specific antigen (PSA) 24 hours after PAE did not differ between groups (P > .05). Coils were used in 6 patients receiving cPAE and 4 patients receiving bPAE (14.0% and 8.70%, P = .51). Assessments at 6 months after PAE showed mean IPSS reduction was 7.58 ± 6.88 after cPAE and 8.30 ± 8.12 after bPAE (P = .65); mean prostate volume reduction was 21.9 cm3 ± 51.6 (18.2%) after cPAE and 6.15 cm3 ± 14.6 (7.3%) after bPAE (P = .05); mean PSA reduction was 0.9 ng/mL ± 2.22 after cPAE and 0.22 ng/mL ± 1.65 after bPAE (P = .10). Penile skin lesions (n = 3) and rectal bleeding (n = 2) were documented only in patients receiving cPAE (11.9%, P = .01). No major adverse events occurred. Conclusions: bPAE is as effective as cPAE in treating benign prostatic hyperplasia with a potential to reduce nontarget embolization.info:eu-repo/semantics/publishedVersio

Free-electron Model for Mesoscopic Force Fluctuations in Nanowires

When two metal electrodes are separated, a nanometer sized wire (nanowire) is formed just before the contact breaks. The electrical conduction measured during this retraction process shows signs of quantized conductance in units of G_0=2e^2/h. Recent experiments show that the force acting on the wire during separation fluctuates, which has been interpreted as being due to atomic rearrangements. In this report we use a simple free electron model, for two simple geometries, and show that the electronic contribution to the force fluctuations is comparable to the experimentally found values, about 2 nN.Comment: 4 pages, 3 figures, reference correcte