3,935 research outputs found

    Lipid content and biomass analysis in autotrophic and heterotrophic algal species

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    Biofuels are a form of renewable energy derived from living matter, typically plants. The push for biofuels began in order to decrease the amount of carbon dioxide (CO2) released into the atmosphere, as biofuels are essentially carbon neutral. The idea is the same amount of CO2 the plants took in to perform photosynthesis will then be released in the burning of the biofuels. Algae is an excellent source of biofuels because it grows quickly and is versatile in terms of the type of fuel it can produce. The two most common mechanisms for algae growth are heterotrophic or photoautotrophic. Heterotrophically grown algae uses an exogenous energy source, such as glucose, and uses the energy stored in it to perform cellular functions. Glucose also serves as a source of carbon and hydrogen, which are the primary elements found in lipids. In addition heterotrophic algae requires other nutrients for survival, such as water, vitamins, and inorganic ions. Algae grown photoautotrophically uses pigments in cellular photoreceptors to convert energy from light into adenosine triphosphate (ATP), an energy source, and to produce glucose. It also requires water, vitamins, and inorganic ions like the heterotrophic algae does. Some algal species, such as Chlorella zofingiensis, can be grown both photoautotrophically and heterotrophically. This algae species will be the subject of our experiment. Our experiment seeks to discover the most efficient way of growing algae to produce the highest amount of lipids. In addition to serving as a key component of cell and organelle membranes, lipids are a common form of high efficiency, long-term energy storage for living organisms, which is why lipids are extracted and processed to form biofuels. We propose growing one species of algae photoautotrophically by providing it with proper amounts of light but eliminating any glucose available. We will also grow the same species heterotrophically, with exogenous access to glucose, but eliminating all exposure to light sources. Finally, we will grow the same species mixotrophically with access to both glucose and light. Once the algae is grown, it will be harvested and analyzed for its lipid profile to determine which algae sample has the highest percent lipid content. We will also measure the percent biomass of each sample to determine which primary energy source leads to the greatest amount of total algal growth, percent organic material, and percent lipid content. We predict the algae grown with access to both sunlight and exogenous glucose will produce both the highest lipid content and the highest percent of biomass

    Combining social network analysis and the NATO Approach Space to define agility. Topic 2: networks and networking

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    This paper takes the NATO SAS-050 Approach Space, a widely accepted model of command and control, and gives each of its primary axes a quantitative measure using social network analysis. This means that the actual point in the approach space adopted by real-life command and control organizations can be plotted along with the way in which that point varies over time and function. Part 1 of the paper presents the rationale behind this innovation and how it was subject to verification using theoretical data. Part 2 shows how the enhanced approach space was put to use in the context of a large scale military command post exercise. Agility is represented by the number of distinct areas in the approach space that the organization was able to occupy and there was a marked disparity between where the organization thought it should be and where it actually was, furthermore, agility varied across function. The humans in this particular scenario bestowed upon the organization the levels of agility that were observed, thus the findings are properly considered from a socio-technical perspective

    Study of an ILC Main Linac that Follows the Earth Curvature

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    In the base line configuration, the tunnel of the ILC will follow the earth curvature. The emittance growth in a curved main linac has been studied including static and dynamic imperfections. These include effects due to current ripples in the power supplies of the steering coils and the impact of the beam position monitors scale errors

    Where do we go from here? An assessment of navigation performance using a compass versus a GPS unit

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    The Global Positioning System (GPS) looks set to replace the traditional map and compass for navigation tasks in military and civil domains. However, we may ask whether GPS has a real performance advantage over traditional methods. We present an exploratory study using a waypoint plotting task to compare the standard magnetic compass against a military GPS unit, for both expert and non-expert navigators. Whilst performance times were generally longer in setting up the GPS unit, once navigation was underway the GPS was more efficient than the compass. For mediumto long-term missions, this means that GPS could offer significant performance benefits, although the compass remains superior for shorter missions. Notwithstanding the performance times, significantly more errors, and more serious errors, occurred when using the compass. Overall, then, the GPS offers some clear advantages, especially for non-expert users. Nonetheless, concerns over the development of cognitive maps remain when using GPS technologies

    Recovery of Injured Giant Barrel Sponges, Xestospongia muta, Offshore Southeast Florida

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    Giant barrel sponges, Xestospongia muta, are abundant and important components of the southeast Florida reef system, and are frequently injured from anthropogenic and natural disturbances. There is limited information on the capacity of X. muta to recover from injury and on methods to reattach X. muta fragments. In late 2002, hundreds of barrel sponges offshore southeast Florida (Broward County) were accidentally injured during an authorized dredging operation. In early 2003, two to three months post-injury, 93% of 656 assessed injured sponges appeared to be recovering. In 2006, three years post-injury, nearly 90% of 114 monitored sponges continued to show signs of recovery. Growth rates were estimated by measuring sponge height above visual injury scars and ranged from 0.7 cm yr- ¹ to 6.0 cm yr- ¹. Information on the artificially reattached fragments is limited but did show that X. muta fragments can reattach. This study provides evidence that X. muta in southeast Florida can naturally recover. Details on sponge size class associated recovery processes and growth were not collected due to event associated legal issues limiting the study. Studies to determine detailed growth rates and recovery success for different injury and restoration scenarios will further facilitate restoration decision making by resource managers
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