301 research outputs found

    Distributions and abundances of Pacific sardine (Sardinops sagax) and other pelagic fishes in the California Current Ecosystem during spring 2006, 2008, and 2010, estimated from acoustic–trawl surveys

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    The abundances and distributions of coastal pelagic fish species in the California Current Ecosystem from San Diego to southern Vancouver Island, were estimated from combined acoustic and trawl surveys conducted in the spring of 2006, 2008, and 2010. Pacific sardine (Sardinops sagax), jack mackerel (Trachurus symmetricus), and Pacific mackerel (Scomber japonicus) were the dominant coastal pelagic fish species, in that order. Northern anchovy (Engraulis mordax) and Pacific herring (Clupea pallasii) were sampled only sporadically and therefore estimates for these species were unreliable. The estimates of sardine biomass compared well with those of the annual assessments and confirmed a declining trajectory of the “northern stock” since 2006. During the sampling period, the biomass of jack mackerel was stable or increasing, and that of Pacific mackerel was low and variable. The uncertainties in these estimates are mostly the result of spatial patchiness which increased from sardine to mackerels to anchovy and herring. Future surveys of coastal pelagic fish species in the California Current Ecosystem should benefit from adaptive sampling based on modeled habitat; increased echosounder and trawl sampling, particularly for the most patchy and nearshore species; and directed-trawl sampling for improved species identification and estimations of their acoustic target stre

    Environmental assessment of an animal fat based biodiesel: Defining goal, scope and life cycle inventory

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    The energy crisis and environmental problems have resulted in an increase of biofuels production. How- ever, the production cost is the biggest commercialization drawback for fuels such as biodiesel; the high- est cost in its production chain is associated with the raw material. Biodiesel is usually produced from vegetable oils; nevertheless, water supplies, fertilizers and large land areas are required for its produc- tion. An alternative is to use animal fat as the most economic raw material for biodiesel production. It does not compete with food safety and reduces the environmental impact caused by an inadequate dis- posal. But the use of biodiesel causes damages on some different parts of unmodified diesel engines and decrease their performance. Therefore, it is necessary to study additives that modify the thermodynamic and transport properties of biodiesel such as density, viscosity or surface tension. The aim of this research is to present the goal, scope and life cycle inventory necessary to evaluate the potential environmental impacts of ternary diesel + biodiesel + additives blends, as biofuels through life cycle assessment. Mass of reagents and blends components were identified, while they have already been tested and validated from the experimental data. The life cycle scenarios will include beef tallow, biodiesel, diesel and addi- tives production, mixing processes, and blends combustion

    Informal waste pickers in Guayaquil: Recycling rates, environmental benefits, main barriers, and troubles

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    [Abstract]: Systems for managing municipal solid waste are typically ineffective in developing nations because of governments' deficient financial and administrative frameworks, poor rules, and a lack of suitable infrastructure and human resources. The informal sector plays an essential role in these systems by reprocessing waste into secondary raw materials, reducing collection and disposal costs, and, most importantly, benefiting the environment by avoiding incineration and landfilling. However, their actual contributions remain unknown. The present paper aims to understand the role of informal waste pickers (IWPs) in the waste management system of Guayaquil City and their environmental impact through the calculations of the carbon footprint (CF) avoided due to their aid. The survey design gathered information on their personal profiles, types, and rates of collected recyclables, market conditions, their main barriers, and troubles regarding their formalization. The results of the survey demonstrate that waste picking is mostly a male-driven activity, the average daily mass collected per IWP is 13 kg, the most collected recyclable waste is polyethylene terephthalate, their average monthly income is $179, and the total avoided CF of the entire informal waste picking process is almost 14 thousand tons of CO2 eq yearly. Further, IWPs prefer to operate alone, and only 16% of them would join a cooperative, despite their numerous financial, logistical, and personal challenges

    Denudation and geomorphic change in the Anthropocene; a global overview

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    The effects of human activity on geomorphic processes, particularly those related to denudation/sedimentation, are investigated by reviewing case studies and global assessments covering the past few centuries. Evidence we have assembled from different parts of the world, as well as from the literature, show that certain geomorphic processes are experiencing an acceleration, especially since the mid-twentieth century. This suggests that a global geomorphic change is taking place, largely caused by anthropogenic landscape changes

    Extracellular Matrix Aggregates from Differentiating Embryoid Bodies as a Scaffold to Support ESC Proliferation and Differentiation

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    Embryonic stem cells (ESCs) have emerged as potential cell sources for tissue engineering and regeneration owing to its virtually unlimited replicative capacity and the potential to differentiate into a variety of cell types. Current differentiation strategies primarily involve various growth factor/inducer/repressor concoctions with less emphasis on the substrate. Developing biomaterials to promote stem cell proliferation and differentiation could aid in the realization of this goal. Extracellular matrix (ECM) components are important physiological regulators, and can provide cues to direct ESC expansion and differentiation. ECM undergoes constant remodeling with surrounding cells to accommodate specific developmental event. In this study, using ESC derived aggregates called embryoid bodies (EB) as a model, we characterized the biological nature of ECM in EB after exposure to different treatments: spontaneously differentiated and retinoic acid treated (denoted as SPT and RA, respectively). Next, we extracted this treatment-specific ECM by detergent decellularization methods (Triton X-100, DOC and SDS are compared). The resulting EB ECM scaffolds were seeded with undifferentiated ESCs using a novel cell seeding strategy, and the behavior of ESCs was studied. Our results showed that the optimized protocol efficiently removes cells while retaining crucial ECM and biochemical components. Decellularized ECM from SPT EB gave rise to a more favorable microenvironment for promoting ESC attachment, proliferation, and early differentiation, compared to native EB and decellularized ECM from RA EB. These findings suggest that various treatment conditions allow the formulation of unique ESC-ECM derived scaffolds to enhance ESC bioactivities, including proliferation and differentiation for tissue regeneration applications. © 2013 Goh et al
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