Consequences of ocean scale hypoxia constrained habitat for tropical pelagic fishes

Large areas of cold hypoxic water occur as distinct strata in the eastern tropical Pacific and Atlantic oceans as a result of high productivity initiated by intense nutrient upwelling. Recent studies show that this stratum restricts the depth distribution of tropical pelagic marlins, sailfish, and tunas in the eastern tropical Pacific by compressing the acceptable physical habitat into a narrow surface layer. This layer extends downward to a variable boundary defined by a shallow thermocline, often at 25 m, above a barrier of cold hypoxic water. The depth distributions of marlin and sailfish monitored with electronic tags and mean dissolved oxygen (DO) and temperature profiles show that this cold hypoxic environment constitutes a lower habitat boundary in the eastern tropical Pacific, but not in the western North Atlantic. where DO is not limiting. However. hypoxia-based habitat compression has not actually been demonstrated in the eastern tropical Atlantic Ocean, despite this region having similar oceanographic features to the eastern tropical Pacific. This paper explores the possibility that habitat compression of tropical pelagic fishes exists in the eastro tropical Atlantic and examines possible consequences of this phenomenon. We used Atlantic-wide catches of yellowfin tuna (Thunnus albacares) as an example why habitat compression off west Africa could eventually affect the total Atlantic stock

Application of superplastically formed and diffusion bonded aluminum to a laminar flow control leading edge

NASA sponsored the Aircraft Energy Efficiency (ACEE) program in 1976 to develop technologies to improve fuel efficiency. Laminar flow control was one such technology. Two approaches for achieving laminar flow were designed and manufactured under NASA sponsored programs: the perforated skin concept used at McDonnell Douglas and the slotted design used at Lockheed-Georgia. Both achieved laminar flow, with the slotted design to a lesser degree (JetStar flight test program). The latter design had several fabrication problems concerning springback and adhesive flow clogging the air flow passages. The Lockheed-Georgia Company accomplishments is documented in designing and fabricating a small section of a leading edge article addressing a simpler fabrication method to overcome the previous program's manufacturing problems, i.e., design and fabrication using advanced technologies such as diffusion bonding of aluminum, which has not been used on aerospace structures to date, and the superplastic forming of aluminum

The evaluation of partial binocular overlap on car maneuverability: A pilot study

An engineering approach to enlarge the helmet mounted display (HMD) field of view (FOV) and maintain resolution and weight by partially overlapping the binocular FOV has received renewed interest among human factors scientists. It is evident, based on the brief literature review, that any panoramic display with a binocular overlap, less than a minimum amount, annoys the viewer, degrades performance, and elicits undesirable behavior. The major finding is that across the 60 deg conditions, subjects moved their heads a greater distance (by about 5 degs on each side) than in the 180 deg condition, presumably to compensate for the lack of FOV. It is quite clear that the study, based on simple car maneuverability and two subjects, reveals differences in FOV, but nothing significant between binocular overlap levels and configurations. This tentatively indicates that some tradeoffs of binocular vision for a larger overall display FOV are acceptable

Relationships of the silver rice rat Oryzomys argentatus (Rodentia: Muridae)

Nine skulls of the rare Oryzomys argentatus are compared to 109 skulls of the six races of O. palustris. Mahalanobis distance is greater between O. argentatus and all Floridian forms of O. palustris than the Floridian forms are from each other. In a canonical discriminant analysis, two models grouping O. argentatus with one or both of the insular races of O. palustris (sanibeli and planirostris) were shown by the Roy\u27s Greatest Root statistic to fit the data less well than a model in which O. argentatus was regarded as distinct. A one-way ANOVA and Duncan\u27s Multiple Range Test on the variation in nasal bone proportions show that there are two significantly different groups of these Oryzomys (p \u3c 0.05): all O. palustris together and O. argentatus alone. We hypothesize O. argentatus originated on the Lower Keys in the late Sangamon and underwent selection for character divergence in sympatry with O. palustris during the Wurm

Preliminary investigation into the use of surface modification techniques to detect organic materials in meteorites

Many carbonaceous chondrites (CCs) display evidence of aqueous and/or thermal alteration of their component minerals. In addition, CCs also contain up to ca. 5% carbon, much of which is organic, insoluble, involatile and unreactive, and known as insoluble organic material (IOM). It is not known if there is a causal connection between the mineral alteration, and formation or modification of organic materials; however by understanding the relationships between them, any connections (chemical or physical) could be established

Can we improve the prediction of hip fracture by assessing bone structure using shape and appearance modelling?

Copyright 2013 Elsevier B.V., All rights reserved.Peer reviewedPreprin

Development of visualisation methodology for organic materials contained within carbonaceous chondrites

The development of methodology for the derivatisation of the organic components of carbonaceous chondrites is described. This methodology will be used to determine the location of organic materials, in situ, and at high resolution