Assessment of Helical Anchors Bearing Capacity for Offshore Aquaculture Applications

Aquaculture in Maine is an important industry with expected growth in the coming years to provide food in an ecological and environmentally sustainable way. Accommodating such growth, farmers need more reliable engineering solutions, such as improving their anchoring systems. Current anchoring methods include deadweights (concrete blocks) or drag embedment anchors, which are of relatively simple construction and installation. However, in the challenge of accommodating larger loads, farmers have used larger sizes of the current anchors rising safety issues and costs during installation and decommissioning. Helical anchors are a foundation type extensively used onshore with the potential of adjusting the aquaculture growth demand, though research understanding their lateral and inclined capacity needs to be performed first. This study addresses such topic by performing 3D finite element simulations of helical anchors and studies their reliability for offshore aquaculture farming. Results obtained in this research indicate that the helical anchors capacity could be related to either pure vertical or horizontal resistances, depending on the load inclination angle. Reliability evaluation of helical anchors for inclined loading demand from an oyster aquaculture farm using the Hasoferd-Lind method, indicated these anchors are feasible for operational aquaculture loads

Blurred Lines Between Competition and Parasitism

Accurately describing the ecological relationships between species is more than mere semantics-doing so has profound practical and applied implications, not the least of which is that inaccurate descriptions can lead to fundamentally incorrect predicted outcomes of community composition and functioning. Accurate ecological classifications are particularly important in the context of global change, where species interactions can change rapidly following shifts in species composition. Here, we argue that many common ecological interactions-particularly competition and parasitism-can be easily confused and that we often lack empirical evidence for the full reciprocal interaction among species. To make our case and to propose a theoretical framework for addressing this problem, we use the interactions between lianas and trees, whose outcomes have myriad implications for the ecology and conservation of tropical forests (e.g., Schnitzer et al. 2015)

The AMIGA sample of isolated galaxies - II. Morphological refinement

We present a complete POSS II-based refinement of the optical morphologies for galaxies in the Karatchenseva's Catalog of Isolated Galaxies that forms the basis of the AMIGA project. Comparison with independent classifications made for an SDSS overlap sample of more than 200 galaxies confirms the reliability of the early vs. late-type discrimination and the accuracy of spiral subtypes within DeltaT = 1-2. CCD images taken at the OSN were also used to solve ambiguities. 193 galaxies are flagged for the presence of nearby companions or signs of distortion likely due to interaction. This most isolated sample of galaxies in the local Universe is dominated by 2 populations: 1) 82% spirals (Sa-Sd) with the bulk being luminous systems with small bulges (63% between types Sb-Sc) and 2) a significant population of early-type E-S0 galaxies (14%). Most of the types later than Sd are low luminosity galaxies concentrated in the local supercluster where isolation is difficult to evaluate. The late-type spiral majority of the sample spans a luminosity range M_B-corr = -18 to -22 mag. Few of the E/S0 population are more luminous than -21.0 marking an absence of, an often sought, super L* merger (eg fossil elliptical) population. The rarity of high luminosity systems results in a fainter derived M* for this population compared to the spiral optical luminosity function (OLF). The E-S0 population is from 0.2 to 0.6 mag fainter depending how the sample is defined. This marks the AMIGA sample as almost unique among samples that compare early and late-type OLFs separately. In other samples, which always involve galaxies in higher density environments, M*(E/S0) is almost always 0.3-0.5 mag brighter than M*(S), presumably reflecting a stronger correlation between M* and environmental density for early-type galaxies.Comment: A&A accepted, 13 pages, 9 figures, 8 tables. Higher resolution Fig. 1 and full tables are available on the AMIGA (Analysis of the interstellar Medium of Isolated GAlaxies) website at http://www.iaa.es/AMIGA.htm

Mental disorders and drug/alcohol use in patients commencing extensively drug-resistant tuberculosis treatment.

Mental disorders and alcohol/drug use worsen treatment outcomes for multidrug-resistant tuberculosis (TB), but data are lacking for extensively drug-resistant (XDR) TB. We investigated the association of baseline mental disorders and alcohol/drug use on XDR-TB treatment outcomes in a retrospective study of 53 XDR-TB Peruvian patients during 2010-2012. Logistic regression estimated the odds ratios for unfavourable XDR-TB treatment outcomes. Overall treatment success was 25%. Mental disorders and drug/alcohol use were found in respectively 22.4% and 20.4% of patients; neither were associated with unfavourable treatment outcomes. Future research should explore the relationship between mental health and drug/alcohol use in XDR-TB treatment outcomes

The role of environment in triggering starburst galaxies: A sample of isolated galaxies

The project AMIGA (Analysis of the interstellar Medium of Isolated GAlaxies) will provide a statistically significant sample of the most isolated galaxies in the northern sky. Such a control sample is necessary to assess the role of the environment in galaxy properties and evolution. The sample is based on the Catalogue of Isolated Galaxies (CIG, Karachentseva, 1973) and the database will include blue and near-infrared luminosities, far-infrared (FIR) emission, atomic gas (HI) emission, radio continuum, and, for a redshift limited subsample of about 200 galaxies, CO and H$\alpha$ emission. The data will be released and periodically updated at http://www.iaa.csic.es/AMIGA.html. Here, we present the project and its status, as well as a preliminary analysis of the relation between star formation activity and the environment. We found a trend that the galaxies with asymmetric HI spectrum also tend to show an enhanced star formation, traced by a high value of $L_{FIR}/M(HI)$, indicating that a perturbed gas kinematics and enhanced SF are related.Comment: 6 pages, to appear in "The Evolution of Starbursts", ed. S. Huettemeister et al., AIP Proceeding

Phase space analysis of quintessence fields trapped in a Randall-Sundrum braneworld: a refined study

In this paper we investigate, from the dynamical systems perspective, the evolution of an scalar field with arbitrary potential trapped in a Randall-Sundrum's Braneworld of type II. We consider an homogeneous and isotropic Friedmann-Robertson-Walker (FRW) brane filled also with a perfect fluid. Center Manifold Theory is employed to obtain sufficient conditions for the asymptotic stability of de Sitter solution. We obtain conditions on the potential for the stability of scaling solutions as well for the stability of the scalar-field dominated solution. We prove the there are not late time attractors with 5D-modifications (they are saddle-like). This fact correlates with a transient primordial inflation. In the particular case of a scalar field with potential $V=V_{0}e^{-\chi\phi}+\Lambda$ we prove that for $\chi<0$ the de Sitter solution is asymptotically stable. However, for $\chi>0$ the de Sitter solution is unstable (of saddle type).Comment: 12 pages, 8 figures, one affiliation added, matches the published version at CQ

AMIGA: Very low environment galaxies in the local Universe

2 pages, no figure, to be published in SF2A-2005, EdP Sciences, F. Casoli, T. Contini, J.M. Hameury and L. Pagani, editorsThe evolutionary history of galaxies is thought to be strongly conditioned by the environment. In order to quantify and set limits on the role of nurture one must identify and study an isolated sample of galaxies. But it is not enough to identify a small number of the "most isolated" galaxies. We begin with 950 galaxies from the Catalogue of Isolated Galaxies (Karachentseva 1973) and reevaluate isolation using an automated star-galaxy classification procedure on large digitised POSS-I fields. We define, compare and discuss various criteria to quantify the degree of isolation for these galaxies: Karachentseva's revised criterion, local surface density computations and an estimation of the external tidal force affecting each isolated galaxy. Comparison of multi-wavelength ISM properties, in particular the H$\alpha$ emission line, will allow us to separate the influence of the environment from the one due to the initial conditions at formation