Phase diagram of the antiferromagnetic XY model in two dimensions in a magnetic field

The phase diagram of the quasi-two-dimensional easy-plane antiferromagnetic model, with a magnetic field applied in the easy plane, is studied using the self-consistent harmonic approximation. We found a linear dependence of the transition temperature as a function of the field for large values of the field. Our results are in agreement with experimental data for the spin-1 honeycomb compound BaNi_2V_2O_3Comment: 3 page

Photometric and proper motion study of neglected open cluster NGC 2215

Optical UBVRI photometric measurements using the Faulkes Telescope North were taken in early 2011 and combined with 2MASS JHK$_s$ and WISE infrared photometry as well as UCAC4 proper motion data in order to estimate the main parameters of the galactic open cluster NGC 2215 of which large uncertainty exists in the current literature. Fitting a King model we estimate a core radius of 1.12$'\pm$0.04$'$ (0.24$\pm$0.01pc) and a limiting radius of $4.3'\pm$0.5$'$ (0.94$\pm$0.11pc) for the cluster. The results of isochrone fits indicates an age of $log(t)=8.85\pm0.10$ with a distance of $d=790\pm90$pc, a metallicity of $[Fe/H]=-0.40\pm0.10$ dex and a reddening of $E(B-V)=0.26\pm0.04$. A proportion of the work in this study was undertaken by Australian and Canadian upper secondary school students involved in the Space to Grow astronomy education project, and is the first scientific publication to have utilized our star cluster photometry curriculum materials.Comment: 10 pages, 9 Figures, 3 Table

Multimodal interaction with BIM data in immersive virtual reality

In this paper, we combine the potential brought by BIM standards to AEC processes, with the recent trends and results taken from human-computer interaction (HCI). As a result, our system supports the visualization and interaction with 3D BIM models of buildings, at full scale in an immersive virtual reality (VR) environment, using natural and multimodal HCI, namely, combining gesture with speech. We´ve carried usability and user satisfaction evaluation with a panel of architects, engineers and architect students and our research shows that such an environment allows a deeper understanding of the work throughout the design process and improve the communication between AEC specialties, during design briefs. We have concluded also, that our technology offers great benefits during all the stages of design, from the initial phase of conceptual design until the detailed stages up to the construction work. The practical experimentation of our in-house developed system, was possible by taking advantage of the virtual reality facilities of ISCTE-IUL, namely, its PocketCAVE lab.info:eu-repo/semantics/acceptedVersio

Identification of yeasts isolated from wine-related environments and capable of producing 4-ethylphenol

www.elsevier.nl/locate/jnlabr/yfmic DOI:10.1016/S0740-0020(02)00152-1The ability to produce 4-ethylphenol from the substrate p-coumaric acid in synthetic media was evaluated for several yeast species associated with wine production.Molar conversion rates as high as 90% were found by only Dekkera bruxellensis, D. anomala and by some unidentified strains isolated from wine-related environments.Other unidentified strains produced traces of 4-ethylphenol. All unidentified strains showed the same cultural characteristics as D. bruxellensis when grown on DBDM (Dekkera/Brettanomyces differential medium) agar.The determination of long-chain fatty acid compositions and the utilization of peptide nucleic acid (PNA) probes specific for D. bruxellensis showed that the unidentified strains did not belong to this species.Further identification, by restriction pattern generated from PCR-amplification of the 5.8S rRNA gene and the two internal transcribed spacers (ITS), assigned the unidentified strains to Candida cantarelli, C. wickerhamii, Debaryomyces hansenii, Kluyveromyces lactis and Pichia guilliermondii.However, only some strains of P. guilliermondii were capable of converting p-coumaric acid into 4-ethylphenol with efficiencies close to those observed in D. bruxellensis and D. anomala

On the Nonlinear Stability of Asymptotically Anti-de Sitter Solutions

Despite the recent evidence that anti-de Sitter spacetime is nonlinearly unstable, we argue that many asymptotically anti-de Sitter solutions are nonlinearly stable. This includes geons, boson stars, and black holes. As part of our argument, we calculate the frequencies of long-lived gravitational quasinormal modes of AdS black holes in various dimensions. We also discuss a new class of asymptotically anti-de Sitter solutions describing noncoalescing black hole binaries.Comment: 26 pages. 5 figure

Parasitic infections in two Benthopelagic fish from Amazon: the Arowana Osteoglossum bicirrhosum (Osteoglossidae) and Oscar Astronotus ocellatus (Cichlidae).

The parasitic fauna of wild Osteoglossum bicirrhosum from central Amazon (Brazil) and wild Astronotus ocellatus from eastern Amazon (Brazil) as well as the host-parasite relationship were evaluated. 87.5% O. bicirrhosum were parasitized only by Gonocleithrum aruanae (Monogenoidea). 92.8% A. ocellatus were parasitized by Ichthyophthirius multifiliis (Ciliophora), Gussevia asota (Monogenoidea), Posthodiplostomum sp. metacercariae (Diplostomidae), Procamallanus inopinatus adults and Contracaecum larvae (Anisakidae). High levels of infection by G. aruanae occurred in O. bicirrhosum while in A. ocellatus the highest levels of infection were caused by helminthes ectoparasites such as G. asota, and endoparasites such as Posthodiplostomum sp., P. inopinatus and Contracaecum sp. There was a significant (p>0.05) negative correlation between the intensity of helminthes species and the relative condition factor (Kn) from A. ocellatus, indicating that these parasites are pathogenic for hosts. The parasite fauna of O. bicirrhosum was scarce, while the parasites for A. ocellatus were mainly helminthes species, including adults and larval forms. Such differences on parasites fauna of both omnivore hosts may due to their history life as well as environmental and biological factors

Relação peso-comprimento e fator de condição relativo (Kn) do pirarucu Arapaima gigas Schinz, 1822 (Arapaimidae) em cultivo semi-intensivo no estado do Amazonas, Brasil.

O pirarucu Arapaima gigas (Osteoglossiformes, Arapaimidae), peixe da bacia amazônica, apresenta alta taxa de crescimento e tolerância a alta densidade de estocagem, tem rusticidade ao manuseio e aceita alimentação artificial quando treinado no início da vida, características relevantes para o cultivo de peixe. Neste estudo, a relação peso-comprimento (W=a·Lb) e o fator de condição relativo (Kn) foram estimados para alevinos, juvenis e jovens de pirarucus cultivados em piscicultura semi-intensiva no município de Manacapuru, estado do Amazonas, na Amazônia central, Brasil. Alevinos foram previamente treinados para aceitar ração comercial durante no início da vida e depois foram alimentados com ração para peixes contendo 45% de proteína bruta. A equação relação peso-comprimento mostrou crescimento do tipo isométrico, com valor da constante de regressão (b) igual 3,068. O Kn variou de 0.811 a 1.170 (média de 1.007 ± 0.059) e esses valores elevados indicaram boas condições corporais dos peixes nas condições cultivadas

Three-dimensional wave breaking

Although a ubiquitous natural phenomenon, the onset and subsequent process of surface wave breaking are not fully understood. Breaking affects how steep waves become and drives air–sea exchanges1. Most seminal and state-of-the-art research on breaking is underpinned by the assumption of two-dimensionality, although ocean waves are three dimensional. We present experimental results that assess how three-dimensionality affects breaking, without putting limits on the direction of travel of the waves. We show that the breaking-onset steepness of the most directionally spread case is double that of its unidirectional counterpart. We identify three breaking regimes. As directional spreading increases, horizontally overturning ‘travelling-wave breaking’ (I), which forms the basis of two-dimensional breaking, is replaced by vertically jetting ‘standing-wave breaking’ (II). In between, ‘travelling-standing-wave breaking’ (III) is characterized by the formation of vertical jets along a fast-moving crest. The mechanisms in each regime determine how breaking limits steepness and affects subsequent air–sea exchanges. Unlike in two dimensions, three-dimensional wave-breaking onset does not limit how steep waves may become, and we produce directionally spread waves 80% steeper than at breaking onset and four times steeper than equivalent two-dimensional waves at their breaking onset. Our observations challenge the validity of state-of-the-art methods used to calculate energy dissipation and to design offshore structures in highly directionally spread seas