Thermal garment

An anthropomorphic thermal garment made entirely of fluid-carrying tubing, joined in such a way that the tubes form a network or mesh fabric, is described

Tonic and phasic nitric oxide signals in hippocampal long-term potentiation

Nitric oxide ( NO) participates in long-term potentiation (LTP) and other forms of synaptic plasticity in many different brain areas but where it comes from and how it acts remain controversial. Using rat and mouse hippocampal slices, we tested the hypothesis that tonic and phasic NO signals are needed and that they derive from different NO synthase isoforms. NMDA increased NO production in a manner that was potently inhibited by three different neuronal NO synthase ( nNOS) inhibitors. Tonic NO could be monitored after sensitizing guanylyl cyclase-coupled NO receptors, allowing the very low ambient NO concentrations to be detected by cGMP measurement. The levels were unaffected by inhibition of NMDA receptors, nNOS, or the inducible NO synthase ( iNOS). iNOS was also undetectable in protein or activity assays. Tonic NO was susceptible to agents inhibiting endothelial NO synthase ( eNOS) and was missing in eNOS knock-out mice. The eNOS knock-out sexhibited a deficiency in LTP resembling that seen in wild-types treated with a NO synthase inhibitor. LTP in the knock-outs could be fully restored by supplying a low level of NO exogenously. Inhibition of nNOS also caused a major loss of LTP, particularly of late-LTP. Again, exogenous NO could compensate, but higher concentrations were needed compared with those restoring LTP in the eNOS knock-outs. It is concluded that tonic and phasic NO signals are both required for hippocampal LTP and the two are generated, respectively, by eNOS and nNOS, the former in blood vessels and the latter in neurons

The 30-cm ion thruster power processor

A power processor unit for powering and controlling the 30 cm Mercury Electron-Bombardment Ion Thruster was designed, fabricated, and tested. The unit uses a unique and highly efficient transistor bridge inverter power stage in its implementation. The system operated from a 200 to 400 V dc input power bus, provides 12 independently controllable and closely regulated dc power outputs, and has an overall power conditioning capacity of 3.5 kW. Protective circuitry was incorporated as an integral part of the design to assure failure-free operation during transient and steady-state load faults. The implemented unit demonstrated an electrical efficiency between 91.5 and 91.9 at its nominal rated load over the 200 to 400 V dc input bus range

Spin Readout Techniques of the Nitrogen-Vacancy Center in Diamond

The diamond nitrogen-vacancy (NV) center is a leading platform for quantum information science due to its optical addressability and room-temperature spin coherence. However, measurements of the NV center's spin state typically require averaging over many cycles to overcome noise. Here, we review several approaches to improve the readout performance and highlight future avenues of research that could enable single-shot electron-spin readout at room temperature.Comment: 21 pages, 7 figure

Limiter Control of a Chaotic RF Transistor Oscillator

We report experimental control of chaos in an electronic circuit at 43.9 MHz, which is the fastest chaos control reported in the literature to date. Limiter control is used to stabilize a periodic orbit in a tuned collector transistor oscillator modified to exhibit simply folded band chaos. The limiter is implemented using a transistor to enable monitoring the relative magnitude of the control perturbation. A plot of the relative control magnitude vs. limiter level shows a local minimum at period-1 control, thereby providing strong evidence that the controlled state is an unstable periodic orbit (UPO) of the uncontrolled system

Testing the convergent retrieval learning theory of testing effects

What is learned from retrieving a memory that is not learned by studying the same information? In response to this question, I have proposed a new theory of retrieval-based learning in which I argue that retrieval strengthens the ability to completely activate all portions of a memory trace from an initial state of partial activation. In effect, retrieval serves to unitize the features of a memory, making the entire memory remain retrievable in the future when cue-related activation may be weaker. This theory, called the Primary and Convergent Retrieval (PCR) model, explains why practice tests produce both better long-term retention and faster retrieval than restudy of the same information. In this dissertation, I explore and test several predictions arising from the assumptions of the PCR model’s learning rule. In Experiment 1, I use evidence from retrieval latencies to demonstrate that even unsuccessful retrieval attempts produce learning. In Experiment 2, I demonstrate retrieval practice does not generalize between retrieval cues, which has important consequences for assumptions about what the features of memory representations may be, and retrieval routes through these features. And in Experiment 3, I show that when the same gradual unfolding of features that is assumed to allow learning during retrieval is deliberately engineered to occur during encoding, it produces the same types of retention and latency benefits produced by retrieval. These experiments further support the PCR model by confirming its prediction about what is learned from testing, and when this learning may be expected. Portions of this dissertation have appeared in previously published works; specifically, much of the general introduction and general discussion has appeared in Hopper & Huber (2018), and the entirety of Experiment 1 is also reported in Hopper & Huber (2019). Experiments 2 and 3 have not yet appeared in any published volume

The Primary and Convergent Retrieval Model of Memory

Memory models typically assume that recall is a two-stage process with learning affecting both processes to the same degree. This equal learning assumption is difficult to reconcile with studies of the \u27testing effect\u27, which reveal different forgetting rates following learning from test practice versus learning from restudy. Here we present a new memory model, termed Primary and Convergent Retrieval (PCR) that assumes successful recall leads to a selective enhancement for the second stage of recall (Convergent Retrieval). We applied this model to existing testing effect data. In two new experiments, we confirmed novel predictions of the PCR model for transfer between retrieval cues and for recall latencies. This is the first formally specified model of the testing effect and it has broad implications for the nature of learning and retrieval

Ownership Structure, Property Performance, Multifamily Properties and REITs

This research extends literature that empirically evaluates the impact of ownership and management structure on property level performance. The results show that multifamily properties owned and managed by real estate investment trusts (REITs) generate higher effective rents at the property level than non-REIT-owned properties. After controlling for positive operating scale and brand effects, REIT property level performance is better than non-REIT property level performance in the market studied. The REIT structure represents diversified scale operators with property management skills. The results imply that the structure of property ownership can impact property performance.