Study to define and verify the personal oral hygiene requirements for extended manned space flight Annual report, 1 Jul. 1968 - 30 Jun. 1969

Astronaut oral hygiene requirements for extended manned space fligh

Surviving Winter: A Fitness-Based Explanation of Hoarding and Hibernation

The purpose of this essay is to provide a quantitative model of the fitness consequences of food hoarding. The model we develop explains storage and hibernation as intertemporal behaviors which maximize fitness. We use the term "fitness" to mean the number of surviving offspring.Center for Research on Economic and Social Theory, Department of Economics, University of Michiganhttp://deepblue.lib.umich.edu/bitstream/2027.42/100944/1/ECON390.pd

Deducing Implications of Fitness Maximization When a Tradeoff Exists Among Alternative Currencies

While the theory of natural selection posits that those behaviors maximizing reproductive success ("fitness") tend to survive, behavioral ecologists frequently explain observed behaviors as maximizing some "currency" on which fitness depends. A weakness of the approach is that reproductive success often depends on more than one currency and behaviors which augment one currency may reduce another. We explain how to deduce from the hypothesis of fitness maximization testable predictions. We expound the approach entirely in terms of two biological examples--a preliminary example involving flower replacement perennial and a more elaborate on involving over-winter hoarding by female mammals.Center for Research on Economic and Social Theory, Department of Economics, University of Michiganhttp://deepblue.lib.umich.edu/bitstream/2027.42/100943/1/ECON389.pd

Unmanned aerial systems (UAS) operators’ accuracy and confidence of decisions:Professional pilots or video game players?

Unmanned Aerial Systems (UAS) operations have outpaced current training regimes resulting in a shortage of qualified UAS pilots. Three potential UAS operator groups were explored for suitability (i.e. video game players [VGP]; private pilots; professional pilots) and examined to assess levels of accuracy, confidence and confidence-accuracy judgements (W-S C-A) during a simulated civilian cargo flight. Sixty participants made 21 decision tasks, which varied across three levels of danger/risk. Scales of Tolerance of Ambiguity, Decision Style and NEO-PIR were also completed. Professional pilots and VGPs exhibited the highest level of decision confidence, with VGPs maintaining a constant and positive W-S C-A relationship across decision danger/risk. As decision danger/risk increased, confidence, accuracy and W-S C-A decreased. Decision danger also had a role to play in the confidence expressed when choosing to intervene or rely on automation. Neuroticism was negatively related, and conscientiousness positively related, to confidence. Intolerance of ambiguity was negatively related to W-S C-A. All groups showed higher levels of decision confidence in decisions controlled by the UAS in comparison to decisions where the operator manually intervened. VGPs display less overconfidence in decision judgements. Findings support the idea that VGPs could be considered a resource in UAS operation

Bioturbation artifacts in zero-age sediments

Author Posting. © American Geophysical Union, 2009. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Paleoceanography 24 (2009): PA4212, doi:10.1029/2008PA001727.Most seafloor sediments are dated with radiocarbon, and the sediment is assumed to be zero-age (modern) when the signal of atmospheric testing of nuclear weapons is present (Fraction modern (Fm) > 1). Using a simple mass balance, we show that even with Fm > 1, half of the planktonic foraminifera at the seafloor can be centuries old, because of bioturbation. This calculation, and data from four core sites in the western North Atlantic indicate that, first, during some part of the Little Ice Age (LIA) there may have been more Antarctic Bottom Water than today in the deep western North Atlantic. Alternatively, bioturbation may have introduced much older benthic foraminifera into surface sediments. Second, paleo-based warming of Sargasso Sea surface waters since the LIA must lag the actual warming because of bioturbation of older and colder foraminifera.This work was funded in part by the Gary Comer Foundation and by NSF grant 0214144. A portion of this work was performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344

Visualization and chemical characterization of the cathode electrolyte interphase using He-ion microscopy and in situ time-of-flight secondary ion mass spectrometry

Unstable cathode electrolyte interphase (CEI) formation increases degradation in high voltage Li-ion battery materials. Few techniques couple characterization of nano-scale CEI layers on the macroscale with in situ chemical characterization, and thus, information on how the underlying microstructure affects CEI formation is lost. Here, the process of CEI formation in a high voltage cathode material, LiCoPO4, has been investigated for the first time using helium ion microscopy (HIM) and in situ time-of-flight (ToF) secondary ion mass spectrometry (SIMS). The combination of HIM and Ne-ion ToF-SIMS has been used to correlate the cycle-dependent morphology of the CEI layer on LiCoPO4 with a local cathode microstructure, including position, thickness, and chemistry. HIM imaging identified partial dissolution of the CEI layer on discharge resulting in in-homogenous CEI coverage on larger LiCoPO4 agglomerates. Ne-ion ToF-SIMS characterization identified oxyfluorophosphates from HF attack by the electrolyte and a Li-rich surface region. Variable thickness of the CEI layer coupled with inactive Li on the surface of LiCoPO4 electrodes contributes to severe degradation over the course of 10 cycles. The HIM–SIMS technique has potential to further investigate the effect of microstructures on CEI formation in cathode materials or solid electrolyte interphase formation in anodes, thus aiding future electrode development

Towards in-situ TEM for Li-ion battery research

Due to recent developments in new battery materials for higher energy density applications there has been growing interest in new characterization techniques capable of time-resolved in situ/in operando analysis of dynamic Battery systems. This review provides an overview on recent development of liquid cell transmission electron microscopy (TEM) for Li-ion battery research and discusses the challenges, highlighting potential research areas. In-situ TEM offers the opportunity to study phenomena including solid electrolyte interphase (SEI) formation and phase changes during battery operation. There are two main challenging areas for in-situ TEM research (1) designing an in-situ TEM electrochemical cell that mimics a ‘real’ cell and (2) quantifying beam damage caused by electron irradiation of the electrolyte

Scavenger Receptors and Their Potential as Therapeutic Targets in the Treatment of Cardiovascular Disease

Scavenger receptors act as membrane-bound and soluble proteins that bind to macromolecular complexes and pathogens. This diverse supergroup of proteins mediates binding to modified lipoprotein particles which regulate the initiation and progression of atherosclerotic plaques. In vascular tissues, scavenger receptors are implicated in regulating intracellular signaling, lipid accumulation, foam cell development, and cellular apoptosis or necrosis linked to the pathophysiology of atherosclerosis. One approach is using gene therapy to modulate scavenger receptor function in atherosclerosis. Ectopic expression of membrane-bound scavenger receptors using viral vectors can modify lipid profiles and reduce the incidence of atherosclerosis. Alternatively, expression of soluble scavenger receptors can also block plaque initiation and progression. Inhibition of scavenger receptor expression using a combined gene therapy and RNA interference strategy also holds promise for long-term therapy. Here we review our current understanding of the gene delivery by viral vectors to cells and tissues in gene therapy strategies and its application to the modulation of scavenger receptor function in atherosclerosis

In situ fracture behavior of single crystal LiNi0.8Mn0.1Co0.1O2 (NMC811)

Single crystal particle morphologies have become highly desirable for next generation cathode materials, removing grain boundary fracture and thereby reducing the surface area exposed to electrolyte. The intrinsic mechanical behavior of single crystal layered oxides, however, is poorly understood. Here, faceted single crystal LiNi0.8Mn0.1Co0.1O2 (NMC811) particles are compressed in situ in a scanning electron microscope (SEM), to determine mechanical deformation mechanisms as a function of crystallographic orientation. In situ, the dynamical deformation sequence observed is initial cracking at the compression zone, followed by accelerated transparticle crack propagation and concurrent (0001) slip band formation. The greatest loads and contact pressure at fracture, non-basal cracking, and activation of multiple basal slip systems in larger (>3 μm) particles, occur for compression normal to the (0001) layered structure. Loading on {012} preferentially activates basal fracture and slip at lower loads. Regardless of particle orientation, non-basal slip systems are not observed, and non-basal cracking and particle rotation occur during compression to compensate for this inability to activate dislocations in 3-dimensions. Crystallographic dependent mechanical behaviour of single crystal NMC811 means that particle texture in cathodes should be monitored, and sources of localised surface stress in cathodes, e. g. particle-to-particle asperity contacts during electrode manufacture, should be minimised