555 research outputs found
Reducing fuel consumption by using a new fuel-efficiency support tool
A fuel-efficiency support tool has been designed, which includes a normative model describing optimal driver behaviour for minimising fuel consumption. If actual behaviour deviates from optimal behaviour, the system presents advice on how to change behaviour. Evaluation revealed that drivers used ~16% less fuel compared with `normal driving
Probing the role of the cationâÏ interaction in the binding sites of GPCRs using unnatural amino acids
We describe a general application of the nonsense suppression methodology for unnatural amino acid incorporation to probe drugâreceptor interactions in functional G protein-coupled receptors (GPCRs), evaluating the binding sites of both the M2 muscarinic acetylcholine receptor and the D2 dopamine receptor. Receptors were expressed in Xenopus oocytes, and activation of a G protein-coupled, inward-rectifying K^+ channel (GIRK) provided, after optimization of conditions, a quantitative readout of receptor function. A number of aromatic amino acids thought to be near the agonist-binding site were evaluated. Incorporation of a series of fluorinated tryptophan derivatives at W6.48 of the D2 receptor establishes a cationâÏ interaction between the agonist dopamine and W6.48, suggesting a reorientation of W6.48 on agonist binding, consistent with proposed ârotamer switchâ models. Interestingly, no comparable cationâÏ interaction was found at the aligning residue in the M2 receptor
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Signal Characteristics of Civil GPS Jammers
This paper surveys the signal properties of 18 commercially
available GPS jammers based on experimental
data. The paper is divided into two distinct tests.
The first characterizes the jamming signals, and the
second test determines the effective range of 4 of the
jammers. The first test uses power spectra from discrete
Fourier transforms (DFTs) of the time series data
to show that all the jammers employ approximately the same jamming method, i.e. linear frequency modulation
of a single tone. The spectra also show that
there are significant jammer-to-jammer variations, including
between jammers of the same model, and that
a given jammerâs signal may vary over time. The first
test also includes measurements of signal power within
frequency bands centered at the L1 and L2 frequencies,
along with the sweep periods and the sweep range at
both frequencies. The second test presents measurements
of the attenuation of the jamming signal necessary
to allow a commercially available GPS receiver to
acquire and track signals from a GPS simulator. From
the attenuation levels and some assumptions about the
antennas used, upper limits on the effective jamming
ranges are calculated for 4 of the jammers, with a resulting
maximum range of 6â9 km.Aerospace Engineering and Engineering Mechanic
A Needs Assessment of Student Support Programs for Adult Students at Tri-County Technical College
Situated in a national landscape of looming decreasing enrollment trends for traditional-aged students, institutions of higher education would do well to consider how to support the persistence of non-traditional students. The definition of non-traditional students can include a wide spectrum of descriptors. This study narrowed that definition to consider adult students, who are 25 years of age or older. The decision to persist is different for adult students at commuter colleges than for traditional-aged students at residential four-year institutions (Braxton, Doyle, Hartley, Hirschy, Jones, & McLendon, 2014). Adult students have a different approach to decision making influenced by their life experiences and related cognitive scheme (Donaldson & Graham, 1999). Tri-County Technical College has identified the adult student population as an important population to focus on in the coming years as the number of available traditional-aged students decreases (Grawe, 2014). With this in mind, it is important to consider how Tri-County can best support its adult students to persist to their education goal.
This needs assessment study identified several existing gaps between needs of adult students at Tri-County and the student support programs and structures at Tri-County Technical College. Through a series of focused conversations, the experiences of adult students were examined to identify those factors that support and those factors that complicate their ability remain enrolled. Comparing these factors to the focus of non-academic student support programs and structures at Tri-County led to the identification of several existing gaps. These gaps comprised the identified needs. Ultimately, a series of six recommendations were provided as opportunities for how Tri-County can adjust its efforts support adult student persistence
Application of Synthetic Biology to Bioregenerative Life Support for Human Spaceflight
The conversion of carbon dioxide into higher value products is a key challenge for the development of closed-loop life support systems for human space flight. Much of the past research on bioregenerative life support systems has focused on plant growth chambers as a solution for CO2 removal and O2 generation, but photosynthetic microorganisms may also have a role to play in these functions. Cyanobacteria have the advantages of relatively high CO2 fixation rates and fairly well-developed molecular biology tools, allowing for genetic engineering approaches to strain improvement. Manned missions to Mars or other targets beyond low Earth orbit will require advances in the nutritional systems for life support on these longer duration missions. A key challenge will likely be supplementing pre-packaged meals with specific nutrients that will be deficient due to problems in long-term storage or low abundance. Vitamin K is one such nutrient that may be important as a supplement. Production of vitamin K for nutrient supplementation during spaceflight will likely require genetic engineering of microorganisms to increase vitamin titers. A microbial bioreactor system that could efficiently convert CO2 to nutritional supplements would be a valuable component for a future advanced life support system. We are exploring biological systems to determine the feasibility of using bioreactors to convert CO2 to higher-value products. We are examining the performance of photosynthetic bacteria engineered to produce sugars, determining rates of production and reliability. We are also engineering microbes to produce higher titers of vitamin K and other potentially important nutrients. The results of this research will offer demonstrations of potential technologies that could be developed further in the future. This work will also provide valuable information for understanding basic science questions about the use of genetically engineered microbes in the microgravity environment
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