On the Gold-Example in Plato\u27s Timaeus (50a5-b5)

Plato imagines someone moulding figures of all kinds in a lump of gold, and continually remoulding each and all into all the others. If someone points to one of these shaped pieces of gold and asks what is it? Three possible replies: by far the safest, it is gold. 2, But never triangle. 3. Unless they are willing to accept such , that has some safety. The most complete previous interpretation of this passage is by Harold Cherniss, AJP 75 (1954) 113-130. This paper discusses the difficulties in Cherniss\u27 interpretation and offers alternatives

Spontaneous formation of a chiral (Mo2O2S2)2+-based cluster driven by dimeric {Te2O6}-based templates

Utilization of [Mo2S2O2(H2O)6]2+ and a tellurite anion led to the formation of three new clusters, 1–3, with unique structural features. The tellurite anion not only templated the formation of [(Mo2O2S2)4(TeO3)(OH)9]3− 1 and [(Mo2O2S2)12(TeO3)4(TeO4)2 (OH)18]10− 3, but also the in situ generation of two different types of dimeric {Te2O6} based moieties induced the spontaneous assembly of the chiral [(Mo2O2S2)10(TeO3)(Te2O6)2(OH)18]8− anionic cluster, 2

Autorotation flight control system

The present invention provides computer implemented methodology that permits the safe landing and recovery of rotorcraft following engine failure. With this invention successful autorotations may be performed from well within the unsafe operating area of the height-velocity profile of a helicopter by employing the fast and robust real-time trajectory optimization algorithm that commands control motion through an intuitive pilot display, or directly in the case of autonomous rotorcraft. The algorithm generates optimal trajectories and control commands via the direct-collocation optimization method, solved using a nonlinear programming problem solver. The control inputs computed are collective pitch and aircraft pitch, which are easily tracked and manipulated by the pilot or converted to control actuator commands for automated operation during autorotation in the case of an autonomous rotorcraft. The formulation of the optimal control problem has been carefully tailored so the solutions resemble those of an expert pilot, accounting for the performance limitations of the rotorcraft and safety concerns

Deploying Hard Real-Time Control Software on Chip-Multiprocessors

Abstract—Deploying real-time control systems software on multiprocessors requires distributing tasks on multiple processing nodes and coordinating their executions using a protocol. One such protocol is the discrete-event (DE) model of computation. In this paper, we investigate distributed discrete-event (DE) with null-message protocol (NMP) on a multicore system for real-time control software. We illustrate analytically and experimentally that even with the null-message deadlock avoidance scheme in the protocol, the system can deadlock due to inter-core message dependencies. We identify two central reasons for such deadlocks: 1) the lack of an upper-bound on packet transmission rates and processing capability, and 2) an unknown upper-bound on the communication network delay. To address these, we propose using architectural features such as timing control and real-time network-on-chips to prevent such message-dependent deadlocks. We employ these architectural techniques in conjunction with a distributed DE strategy called PTIDES for an illustrative car wash station example and later follow it with a more realistic tunnelling ball device application

Effect of reactor irradiation on Santowax OM and WR

Statement of responsibility on title page reads: E.A. Mason, M.L. Lee, S.T. Brewer, and W.N. Bley"Issued: June, 1968."Includes bibliographical referencesM.I.T. DSR Project no. 79819Work performed for the New York Operations Office, U. S. Atomic Energy Commission under contract No. AT(38-1)-33

Learning Heuristics for Quantified Boolean Formulas through Deep Reinforcement Learning

We demonstrate how to learn efficient heuristics for automated reasoning algorithms for quantified Boolean formulas through deep reinforcement learning. We focus on a backtracking search algorithm, which can already solve formulas of impressive size - up to hundreds of thousands of variables. The main challenge is to find a representation of these formulas that lends itself to making predictions in a scalable way. For a family of challenging problems, we learned a heuristic that solves significantly more formulas compared to the existing handwritten heuristics

Cost Effectiveness of a Home-Based Intervention That Helps Functionally Vulnerable Older Adults Age in Place at Home

Evaluating cost effectiveness of interventions for aging in place is essential for adoption in service settings. We present the cost effectiveness of Advancing Better Living for Elders (ABLE), previously shown in a randomized trial to reduce functional difficulties and mortality in 319 community-dwelling elders. ABLE involved occupational and physical therapy sessions and home modifications to address client-identified functional difficulties, performance goals, and home safety. Incremental cost-effectiveness ratio (ICER), expressed as additional cost to bring about one additional year of life, was calculated. Two models were then developed to account for potential cost differences in implementing ABLE. Probabilistic sensitivity analyses were conducted to account for variations in model parameters. By two years, there were 30 deaths (9: ABLE; 21: control). Additional costs for 1 additional year of life was $13,179 for Model 1 and$14,800 for Model 2. Investment in ABLE may be worthwhile depending on society's willingness to pay

Imaging correlates of molecular signatures in oligodendrogliomas.

Molecular subsets of oligodendroglioma behave in biologically distinct ways. Their locations in the brain, rates of growth, and responses to therapy differ with their genotypes. Retrospectively, we inquired whether allelic loss of chromosomal arms 1p and 19q, an early molecular event and favorable prognostic marker in oligodendrogliomas, were reflected in their appearance on magnetic resonance imaging. Loss of 1p and 19q was associated with an indistinct border on T(1) images and mixed intensity signal on T(1) and T(2). Loss of 1p and 19q was also associated with paramagnetic susceptibility effect and with calcification, a common histopathological finding in oligodendrogliomas. These data encourage prospective evaluation of molecular alterations and magnetic resonance imaging characteristics of glial neoplasms

Spitzer Mid-to-Far-Infrared Flux Densities of Distant Galaxies

We study the infrared (IR) properties of high-redshift galaxies using deep Spitzer 24, 70, and 160 micron data. Our primary interest is to improve the constraints on the total IR luminosities, L(IR), of these galaxies. We combine the Spitzer data in the southern Extended Chandra Deep Field with a K-band-selected galaxy sample and photometric redshifts from the Multiwavelength Survey by Yale-Chile. We used a stacking analysis to measure the average 70 and 160 micron flux densities of 1.5 < z < 2.5 galaxies as a function of 24 micron flux density, X-ray activity, and rest-frame near-IR color. Galaxies with 1.5 < z < 2.5 and S(24)=53-250 micro-Jy have L(IR) derived from their average 24-160 micron flux densities within factors of 2-3 of those derived from the 24 micron flux densities only. However, L(IR) derived from the average 24-160 micron flux densities for galaxies with S(24) > 250 micro-Jy and 1.5 < z < 2.5 are lower than those derived using only the 24 micron flux density by factors of 2-10. Galaxies with S(24) > 250 micro-Jy have S(70)/S(24) flux ratios comparable to sources with X-ray detections or red rest-frame IR colors, suggesting that warm dust possibly heated by AGN may contribute to the high 24 micron emission. Based on the average 24-160 micron flux densities, nearly all 24 micron-selected galaxies at 1.5 < z < 2.5 have L(IR) < 6 x 10^12 solar luminosities, which if attributed to star formation corresponds to < 1000 solar masses per year. This suggests that high redshift galaxies may have similar star formation efficiencies and feedback processes as local analogs. Objects with L(IR) > 6 x 10^12 solar luminosities are quite rare, with a surface density ~ 30 +/- 10 per sq. deg, corresponding to ~ 2 +/- 1 x 10^-6 Mpc^-3 over 1.5 < z < 2.5.Comment: Accepted for Publication in ApJ. AASTeX format. 34 pages, 12 figures. Updated references and other small textual revision

Functional Role and Affinity of Inorganic Cations in Stabilizing the Tetrameric Structure of the KcsA K+ Channel

Crystal structures of the tetrameric KcsA K+ channel reveal seven distinct binding sites for K+ ions within the central pore formed at the fourfold rotational symmetry axis. Coordination of an individual K+ ion by eight protein oxygen atoms within the selectivity filter suggests that ion-subunit bridging by cation–oxygen interactions contributes to structural stability of the tetramer. To test this hypothesis, we examined the effect of inorganic cations on the temperature dependence of the KcsA tetramer as monitored by SDS-PAGE. Inorganic cations known to permeate or strongly block K+ channels (K+, Rb+, Cs+, Tl+, NH4+, Ba2+, and Sr2+) confer tetramer stability at higher temperatures (T0.5 range = 87°C to >99°C) than impermeant cations and weak blockers (Li+, Na+, Tris+, choline+; T0.5 range = 59°C to 77°C). Titration of K+, Ba2+, and other stabilizing cations protects against rapid loss of KcsA tetramer observed in 100 mM choline Cl at 90°C. Tetramer protection titrations of K+, Rb+, Cs+, Tl+, and NH4+ at 85°C or 90°C exhibit apparent Hill coefficients (N) ranging from 1.7 to 3.3 and affinity constants (K0.5) ranging from 1.1 to 9.6 mM. Ba2+ and Sr2+ titrations exhibit apparent one-site behavior (N ≅ 1) with K0.5 values of 210 nM and 11 μM, respectively. At 95°C in the presence of 5 mM K+, titration of Li+ or Na+ destabilizes the tetramer with K0.5 values of 57 mM and 109 mM, respectively. We conclude that specific binding interactions of inorganic cations with the selectivity filter are an important determinant of tetramer stability of KscA