1,855 research outputs found
Swamp Works- Multiple Projects
My Surface Systems internship over the summer 2013 session covered a broad range of projects that ranged multiple aspects and fields of engineering and technology. This internship included a project to create a command center for a 120 ton regolith bin, a design and build for a blast shield to add further protection for the Surface Systems engineers, a design for a portable four monitor hyper wall that can extend as large as needed, research and programming a nano drill for a next generation robot, and social media tasks including the making of videos, posting to social networking websites and implementation of a new weekly outreach program to help spread the word about the Swamp Works laboratory. The objectives for the command center were to create a central computer controlled area for the still in production lunar regolith bin. It needed to be easy to use and the operating systems had to be Linux. The objectives for the hyper wall were to build a mobile transport of monitors that could potentially attach to one another. It needed to be light but sturdy, and have the ability to last. The objectives for the blast shield included a robust design that could withstand a small equipment malfunction, while also being convenient for use. The objectives for the nano-drill included the research and implementation of programming for vertical and horizontal movement. The hyper wall and blasts shield project were designed by me in the Pro/Engineer/Creo2 software. Each project required a meeting with the Swamp Works engineers and was declared successful
Mitochondrial retinopathies
The retina is an exquisite target for defects of oxidative phosphorylation (OXPHOS) associated with mitochondrial impairment. Retinal involvement occurs in two ways, retinal dystrophy (retinitis pigmentosa) and subacute or chronic optic atrophy, which are the most common clinical entities. Both can present as isolated or virtually exclusive conditions, or as part of more com-plex, frequently multisystem syndromes. In most cases, mutations of mtDNA have been found in association with mitochondrial retinopathy. The main genetic abnormalities of mtDNA include mutations associated with neurogenic muscle weakness, ataxia and retinitis pigmentosa (NARP) sometimes with earlier onset and increased severity (maternally inherited Leigh syndrome, MILS), single large-scale deletions determining Kearns–Sayre syndrome (KSS, of which retinal dystrophy is a cardinal symptom), and mutations, particularly in mtDNA-encoded ND genes, associated with Leber hereditary optic neuropathy (LHON). However, mutations in nuclear genes can also cause mito-chondrial retinopathy, including autosomal recessive phenocopies of LHON, and slowly progressive optic atrophy caused by dominant or, more rarely, recessive, mutations in the fusion/mitochondrial shaping protein OPA1, encoded by a nuclear gene on chromosome 3q29
Nucleus Accumbens Core and Shell Differentially Encode Reward-Associated Cues after Reinforcer Devaluation
Nucleus accumbens (NAc) neurons encode features of stimulus learning and action selection associated with rewards. The NAc is necessary for using information about expected outcome values to guide behavior after reinforcer devaluation. Evidence suggests that core and shell subregions may play dissociable roles in guiding motivated behavior. Here, we recorded neural activity in the NAc core and shell during training and performance of a reinforcer devaluation task. Long–Evans male rats were trained that presses on a lever under an illuminated cue light delivered a flavored sucrose reward. On subsequent test days, each rat was given free access to one of two distinctly flavored foods to consume to satiation and were then immediately tested on the lever pressing task under extinction conditions. Rats decreased pressing on the test day when the reinforcer earned during training was the sated flavor (devalued) compared with the test day when the reinforcer was not the sated flavor (nondevalued), demonstrating evidence of outcome-selective devaluation. Cue-selective encoding during training by NAc core (but not shell) neurons reliably predicted subsequent behavioral performance; that is, the greater the percentage of neurons that responded to the cue, the better the rats suppressed responding after devaluation. In contrast, NAc shell (but not core) neurons significantly decreased cue-selective encoding in the devalued condition compared with the nondevalued condition. These data reveal that NAc core and shell neurons encode information differentially about outcome-specific cues after reinforcer devaluation that are related to behavioral performance and outcome value, respectively
One month of cocaine abstinence potentiates rapid dopamine signaling in the nucleus accumbens core
Cocaine addiction is a chronic relapsing disorder that is difficult to treat in part because addicts relapse even after extended periods of abstinence. Given the importance of the mesolimbic dopamine (DA) system in drug addiction, we sought to characterize cocaine abstinence induced changes in rapid DA signaling in the nucleus accumbens (NAc). Here, rats were trained to self-administer cocaine for 14 consecutive days, then divided into two groups. Day 1 rats (D1; n = 7) underwent 24 hours of abstinence; Day 30 rats (D30; n = 7) underwent one month of abstinence. After abstinence, all rats underwent a single extinction session. Immediately after, rats were deeply anesthetized and fast scan cyclic voltammetry (FSCV) was used to measure DA release and uptake dynamics in the NAc core before and following a single cocaine injection. We show that one month of cocaine abstinence potentiates the peak concentration of electrically evoked DA in the NAc core following an acute injection of cocaine. This potentiation is not related to alterations in DA uptake parameters, which are unchanged following abstinence, but may reflect alterations in release. These results further support the abundance of literature showing that cocaine abstinence induces neuroplasticity in brain areas implicated in drug reward and relapse. The present findings also demonstrate critical differences between abstinence-induced neuroadaptations in DA signaling and those caused by drug exposure itself
Superconducting tunable flux qubit with direct readout scheme
We describe a simple and efficient scheme for the readout of a tunable flux
qubit, and present preliminary experimental tests for the preparation,
manipulation and final readout of the qubit state, performed in incoherent
regime at liquid Helium temperature. The tunable flux qubit is realized by a
double SQUID with an extra Josephson junction inserted in the large
superconducting loop, and the readout is performed by applying a current ramp
to the junction and recording the value for which there is a voltage response,
depending on the qubit state. This preliminary work indicates the feasibility
and efficiency of the scheme.Comment: 10 pages, 5 figure
A tunable rf SQUID manipulated as flux and phase qubit
We report on two different manipulation procedures of a tunable rf SQUID.
First, we operate this system as a flux qubit, where the coherent evolution
between the two flux states is induced by a rapid change of the energy
potential, turning it from a double well into a single well. The measured
coherent Larmor-like oscillation of the retrapping probability in one of the
wells has a frequency ranging from 6 to 20 GHz, with a theoretically expected
upper limit of 40 GHz. Furthermore, here we also report a manipulation of the
same device as a phase qubit. In the phase regime, the manipulation of the
energy states is realized by applying a resonant microwave drive. In spite of
the conceptual difference between these two manipulation procedures, the
measured decay times of Larmor oscillation and microwave-driven Rabi
oscillation are rather similar. Due to the higher frequency of the Larmor
oscillations, the microwave-free qubit manipulation allows for much faster
coherent operations.Comment: Proceedings of Nobel Symposium "Qubits for future quantum computers",
Goeteborg, Sweden, May 25-28, 2009; to appear in Physica Script
Swamp Works- Multiple Projects
My Surface Systems internship over the summer 2013 session covered a broad range of projects that utilized multiple fields of engineering and technology. This internship included a project to create a command center for a 120 ton regolith bin, for the design and assembly of a blast shield to add further protection for the Surface Systems engineers, for the design and assembly of a portable four monitor hyper wall strip that could extend as large as needed, research and programming a nano drill that could be utilized on a next generation robot or rover, and social media tasks including the making of videos, posting to social networking websites and creation of a new outreach program to help spread the word about the Swamp Works laboratory
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