587 research outputs found
The first use of Fulton's K for assessing and comparing the conditions of inter-tidal fish populations
Fulton's K condition factor was applied, for the first time, to inter-tidal specimens of the shanny (Lipophrys pholis) and long-spined scorpion fish (Taurulus bubalis) from two English rocky shore and two Welsh rocky shore sites during summer 2010 and winter 2011. As both species contribute to the diet of commercial species such as cod (Gadus morhua) and near-threatened species such as the European otter (Lutra lutra), their condition may affect that of these predators. Fulton's K found that inter-tidal Welsh fish maintained a âgoodâ condition between seasons, whereas the inter-tidal English fish were in a poorer condition during winter. Although condition also changed amongst the sites on each coast, further studies are needed into fish morphologies, environmental parameters, prey availabilities and abundances, and fish specimen sex and maturities
Area Regge Calculus and Discontinuous Metrics
Taking the triangle areas as independent variables in the theory of Regge
calculus can lead to ambiguities in the edge lengths, which can be interpreted
as discontinuities in the metric. We construct solutions to area Regge calculus
using a triangulated lattice and find that on a spacelike hypersurface no such
discontinuity can arise. On a null hypersurface however, we can have such a
situation and the resulting metric can be interpreted as a so-called refractive
wave.Comment: 18 pages, 1 figur
Toxicity testing of Atlantic salmon aquaculture chemotherapeutants on spot prawns and benthic invertebrates
Demand for protein sources is high in North America and growing throughout the world. Global declines in fisheries has encouraged coastal regions to embrace aquaculture as a means of reconciling the growing pressures on wild fish stocks with this demand. Intensive salmon farming practices result in periodic infestations with naturally-occurring parasitic copepods referred to as âsea liceâ. To prevent productivity losses, a variety of chemical and physical treatments have been implemented through regulatory systems or emergency applications. One objective of this study is to determine if these chemo-therapeutic treatments pose a risk to other non-target marine organisms including crustaceans such as the Spot prawn (Pandalus platyceros). These organisms can be both culturally and economically important to local First Nations and all residents of the Salish Sea region, as well as crucial components of marine ecosystems. The sub-chronic toxicity of the sea lice pesticides SliceÂź (active ingredient: emamectin benzoate) was assessed for lethal and sub-lethal effects on Pacific prawns, amphipods, and polychaetes which are all found in areas where aquaculture pens exist. Slice and ivermectin whole sediment exposures were conducted. Test concentrations were representative of environmentally-relevant levels. The toxicity of these treatments was assessed using the endpoints of: mortality, growth, and behavioural response. Preliminary results indicate a concentration-response relationship for various selected endpoints
Home-made fish traps reduce the capture of small shannies (Lipophrys pholis) compared to using hand-nets in the UK
A replicated, controlled study in 2011-2012 found that using home-made fish traps reduced the capture of unwanted, small shannies Lipophrys pholis compared to using conventional hand-nets in intertidal habitats
Use of Modeling and Simulation in the Design and Conduct of Pediatric Clinical Trials and the Optimization of Individualized Dosing Regimens
Mathematical models of drug action and disease progression can inform pediatric pharmacotherapy. In this tutorial, we explore the key issues that differentiate pediatric from adult pharmacokinetic (PK) / pharmacodynamic (PD) studies, describe methods to calculate the number of participants to be enrolled and the optimal times at which blood samples should be collected, and therapeutic drug monitoring methods for individualizing pharmacotherapy. The development of pediatricâspecific drug dosing dashboards is also highlighted, with an emphasis on clinicalârelevance and ease of use
Does the Isotropy of the CMB Imply a Homogeneous Universe? Some Generalised EGS Theorems
We demonstrate that the high isotropy of the Cosmic Microwave Background
(CMB), combined with the Copernican principle, is not sufficient to prove
homogeneity of the universe -- in contrast to previous results on this subject.
The crucial additional factor not included in earlier work is the acceleration
of the fundamental observers. We find the complete class of irrotational
perfect fluid spacetimes admitting an exactly isotropic radiation field for
every fundamental observer and show that are FLRW if and only if the
acceleration is zero. While inhomogeneous in general, these spacetimes all
possess three-dimensional symmetry groups, from which it follows that they also
admit a thermodynamic interpretation. In addition to perfect fluids models we
also consider multi-component fluids containing non-interacting radiation, dust
and a quintessential scalar field or cosmological constant in which the
radiation is isotropic for the geodesic (dust) observers. It is shown that the
non-acceleration of the fundamental observers forces these spacetimes to be
FLRW. While it is plausible that fundamental observers (galaxies) in the real
universe follow geodesics, it is strictly necessary to determine this from
local observations for the cosmological principle to be more than an
assumption. We discuss how observations may be used to test this.Comment: replaced with final version. Added discusion and ref
Distributions, Sources, and Transformations of Dissolved and Particulate Iron on the Ross Sea Continental Shelf During Summer
We report water column dissolved iron (dFe) and particulate iron (pFe) concentrations from 50 stations sampled across the Ross Sea during austral summer (January-February) of 2012. Concentrations of dFe and pFe were measured in each of the major Ross Sea water masses, including the Ice Shelf Water and off-shelf Circumpolar Deep Water. Despite significant lateral variations in hydrography, macronutrient depletion, and primary productivity across several different regions on the continental shelf, dFe concentrations were consistently low (\u3c0.1 nM) in surface waters, with only a handful of stations showing elevated concentrations (0.20-0.45 nM) in areas of melting sea ice and near the Franklin Island platform. Across the study region, pFe associated with suspended biogenic material approximately doubled the inventory of bioavailable iron in surface waters. Our data reveal that the majority of the summertime iron inventory in the Ross Sea resides in dense shelf waters, with highest concentrations within 50 m of the seafloor. Higher dFe concentrations near the seafloor are accompanied by an increased contribution to pFe from authigenic and/or scavenged iron. Particulate manganese is also influenced by sediment resuspension near the seafloor but, unlike pFe, is increasingly associated with authigenic material higher in the water column. Together, these results suggest that following depletion of the dFe derived from wintertime convective mixing and sea ice melt, recycling of pFe in the upper water column plays an important role in sustaining the summertime phytoplankton bloom in the Ross Sea polynya
Mining drives extensive deforestation in the Brazilian Amazon
Mining poses significant and potentially underestimated risks to tropical forests worldwide. In Brazil\u27s Amazon, mining drives deforestation far beyond operational lease boundaries, yet the full extent of these impacts is unknown and thus neglected in environmental licensing. Here we quantify mining-induced deforestation and investigate the aspects of mining operations, which most likely contribute. We find mining significantly increased Amazon forest loss up to 70 km beyond mining lease boundaries, causing 11,670 km2 of deforestation between 2005 and 2015. This extent represents 9% of all Amazon forest loss during this time and 12 times more deforestation than occurred within mining leases alone. Pathways leading to such impacts include mining infrastructure establishment, urban expansion to support a growing workforce, and development of mineral commodity supply chains. Mining-induced deforestation is not unique to Brazil; to mitigate adverse impacts of mining and conserve tropical forests globally, environmental assessments and licensing must considered both on- and off-lease sources of deforestation
Moyo Vol. IX N 2
Million, Chris. Dirge For a Restroom, the Search For a Progressive Potty Rages on . 4.
Fisher, Dan. The White Crow: Compassionate Activism in a Tibetan Community-in-Exile . 5.
Barrett, Laura. Indie Films for Indie Spirit (Cinema is the Most Important Art) . 6.
Levine, Robert. American interview. Making a Film About Making a Film: A Cozy Chat With Two Independent Filmmakers . 8.
Hiller, Andy. Cameras and Cappuccinos . 9.
Shuba, Jason J. Technology on Trial: Appreciating Modernity (Technology as Human Progress) . 12.
Dunson, Jim. Technology on Trial: The Role of Choice (Can Progress be The Only Option?) . 13.
Levine, Robert. Cash, Blood, and Coffee (Life as an NYC Film Intern) . 14.
Durica, Paul. The Lost Crusade: Former Editor Muses on the Myth of True Love . 22.
Hankinson, Tom. The Real Appeal of Cinema . 23
Micromechanical finite element modelling of thermo-mechanical fatigue for P91 steels
In this paper, the cyclic plasticity and fatigue crack initiation behaviour of a tempered martensite ferritic steel under thermo-mechanical fatigue conditions is examined by means of micromechanical finite element modelling. The crystal plasticity-based model explicitly reflects the microstructure of the material, measured by electronic backscatter diffraction. The predicted cyclic thermo-mechanical response agrees well with experiments under both in-phase and out-of-phase conditions. A thermo-mechanical fatigue indicator parameter, with stress triaxiality and temperature taken into account, is developed to predict fatigue crack initiation. In the fatigue crack initiation simulation, the out-of-phase thermo-mechanical response is identified to be more dangerous than in-phase response, which is consistent with experimental failure data. It is shown that the behaviour of thermo-mechanical fatigue can be effectively predicted at the microstructural level and this can lead to a more accurate assessment procedure for power plant components
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