953 research outputs found
Reasoning Competence
In the 1970s, various experiments were carried out on\ud
ordinary people"s reasoning powers suggesting our natural\ud
ability to reason does not match up to the normative\ud
standards endorsed in logic and probability theory. The\ud
two most famous of these have come to be termed the\ud
selection experiment, and the conjunction experiment (or\ud
Linda experiment). In the first, Peter Wason asked\ud
subjects to test a rule for cards with numbers on one side\ud
and letters on the other, such as "If the card has a vowel\ud
on one side, it has an odd number on the other" (Wason\ud
1971). Wason"s basic finding was that very few subjects\ud
selected the two cards that are necessary to test such a\ud
rule, suggesting that they do not understand the logic of\ud
conditionals (that they are false just if the antecedent is\ud
true and the consequent false). In the second experiment,\ud
Kahneman and Tversky told subjects a story about a\ud
woman called Linda, and then gave them a list of\ud
statements about Linda concerning what kind of occupation\ud
she has and/or what she does in her free time, and\ud
asked them to rank the statements from most to least\ud
likely. Nearly all subjects ranked the statement Linda is a\ud
bank teller and active in the feminist movement as more\ud
likely than Linda is a bank teller, which contravenes a\ud
fundamental theorem of statistics to the effect that the\ud
probability of any single event A can never be lower than\ud
the probability of both A and some other event B. (Cf.\ud
Tversky & Kahneman 1983.
Solar Decathlon 2014: Techstyle Haus Project Manual
Solar Decathlon 2014 Techstyle Haus Project Manual. The Solar Decathlon competition challenges twenty collegiate teams to design and build sustainable homes that are powered exclusively by solar energy and incorporate sustainable architecture and design. Techstyle Haus is an international Brown University, RISD and University of Applied Sciences Erfurt,Germany collaboration designing a solar passivehaus out of high performance textiles
Approaches to the total synthesis of viridenomycin
Viridenomycin is a polyene macrolide possessing considerable biological activity. Much work has been performed previously within the Whiting group on the development of methodology for the stereoselective synthesis of polyenes and this project builds on this work. New conditions have been developed to allow the HM reactions of electron-poor vinyl iodides with vinylboronate esters. This, combined with previously developed methodology involving the use of iodine monochloride and sodium methoxide to substitute the boronate ester function with an iodide group in a stereoslective manner, allowed the stereoselective synthesis of the Z,Z,E-triene northern hemisphere of viridenomycin. Conditions have been developed to allow further HM reactions and amide couplings of this fragment. In developing conditions for the HM reactions of electron-poor vinyl iodides, a number of side reactions were observed, often in competition with the desired processes. Presented within is a study of these reactions with regard to their generality and mechanism. A number of routes to the highly substituted cyclopentenone fragment of viridenomycin have been developed with the most successful of these showing high yield as well as enantio- and diastereo-selectivity. In this process, a number of unusual cross-ozomides have been isolated in which two new chiral centres were formed with complete diastereoselectivity. Conditions to permit diastereoselective conjugate additions to the cyclopentenones synthesised have been developed. The yields and diastereoselectivites of these reactions were somewhat variable, however, in the best case both proved to be high. Thus, one of the three fragments of viridenomycin have been synthesised whilst another is at a very advanced stage. In addition, some work has been performed on the conditions required for the final assembly
Techstyle Haus Project Drawings
Complete Techstyle Haus project drawings. The Solar Decathlon competition challenges twenty collegiate teams to design and build sustainable homes that are powered exclusively by solar energy and incorporate sustainable architecture and design. Techstyle Haus is an international Brown University, RISD and University of Applied Sciences Erfurt,Germany collaboration designing a solar passivehaus out of high performance textiles
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Effects of ultrasound on the growth and function of bone and periodontal ligament cells <i>in vitro</i>
The effects of therapeutic ultrasound (US) on tissue healing processes in vivo are likely to involve US-induced changes in key cellular functions. However, these have not yet been clearly delineated and the present study has, therefore, examined the effects of a single 5-min CW exposure of 3.00-MHz US on the growth and functional activity of a human osteoblast-like cell line (MG63 cells) and human periodontal ligament (PDL) cells in vitro. Although cell proliferation was found to be largely unaffected by spatial average intensity (ISA) values of between 140–990 mW/cm2, flow cytometry (FCM) analysis showed that there were pronounced and differential effects on cell function. Thus, bone-associated proteins were down-regulated, whereas collagen type I (COL I) was unaffected and fibronectin (FN) was up-regulated at low intensities in MG63 cells. In contrast, bone protein expression was found to be dose-dependent, and FN and COL I were down-regulated in PDL cells. These results show that US has potentially important effects on the functional activities of connective tissue cells in vitro, which could markedly influence tissue repair and regeneration processes in vivo
System Identification for Continuous-time Linear Dynamical Systems
The problem of system identification for the Kalman filter, relying on the
expectation-maximization (EM) procedure to learn the underlying parameters of a
dynamical system, has largely been studied assuming that observations are
sampled at equally-spaced time points. However, in many applications this is a
restrictive and unrealistic assumption. This paper addresses system
identification for the continuous-discrete filter, with the aim of generalizing
learning for the Kalman filter by relying on a solution to a continuous-time
It\^o stochastic differential equation (SDE) for the latent state and
covariance dynamics. We introduce a novel two-filter, analytical form for the
posterior with a Bayesian derivation, which yields analytical updates which do
not require the forward-pass to be pre-computed. Using this analytical and
efficient computation of the posterior, we provide an EM procedure which
estimates the parameters of the SDE, naturally incorporating irregularly
sampled measurements. Generalizing the learning of latent linear dynamical
systems (LDS) to continuous-time may extend the use of the hybrid Kalman filter
to data which is not regularly sampled or has intermittent missing values, and
can extend the power of non-linear system identification methods such as
switching LDS (SLDS), which rely on EM for the linear discrete-time Kalman
filter as a sub-unit for learning locally linearized behavior of a non-linear
system. We apply the method by learning the parameters of a latent,
multivariate Fokker-Planck SDE representing a toggle-switch genetic circuit
using biologically realistic parameters, and compare the efficacy of learning
relative to the discrete-time Kalman filter as the step-size irregularity and
spectral-radius of the dynamics-matrix increases.Comment: 31 pages, 3 figures. Only light changes and restructuring to previous
version mad
Surface Corrosion from Implant–Abutment Couplings with Different Connection Designs Influences Osteoblasts’ Function: A Novel Technique
The improved peri-implant bone response demonstrated when utilizing the platform-switching concept may result from the reduced levels of metal ions released from implant–abutment surfaces to the surrounding tissues. These corrosion products may play a major role in crestal bone remodeling around dental implants. This study evaluated the effect of different implant–abutment couplings (platform-matched vs. platform-switched) on osteoblasts’ function. Titanium alloy and cobalt–chrome alloy abutments were coupled with titanium cylinders, forming either platform-switched or platform-matched groups, and were incubated in human osteoblast cultures utilizing a novel direct-exposure technique. Viability was evaluated over 21 days using Alamar Blue assay. Apoptosis was measured after 24 h using flow cytometry. The expression of genes related to bone resorption was analysed over 21 days using a real-time quantitative polymerase chain reaction assay. Cell viability was reduced from day 4 to day 21 (p < 0.05), with higher rates of early apoptosis (p < 0.05) compared to the controls. Apoptosis was higher in the platform-matched groups (p < 0.05). The tested genes’ expression was up-regulated after 1 and 3 days of exposure to implant–abutment couplings (p < 0.05). The upregulation was more pronounced in platform-matched groups (p < 0.05). Exposure of osteoblasts to implant–abutment couplings induced adverse biological responses, which were more pronounced with platform-matched couplings. These reactions might be related to the increased amounts of metal ions released from the platform-matched couplings, highlighting the possible role of corrosion products in the mediation of crestal bone loss around dental implants
Biodegradable and Sustainable Synthetic Antibodies—A Perspective
Molecular imprinting technology has been around for almost a century, and we have witnessed dramatic advancements in the overall design and production of molecularly imprinted polymers (MIPs), particularly in terms of possible formats of the final products when it comes to truly resembling antibody substitutes, i.e., MIP nanoparticles (MIP NPs). Nonetheless, the overall technology appears to struggle to keep up with the current global sustainability efforts, as recently elucidated in the latest comprehensive reviews, which introduced the “GREENIFICATION” concept. In this review, we will try to elucidate if these advancements in MIP nanotechnology have indeed resulted in a sustainability amelioration. We will do so by discussing the general production and purification strategies for MIP NPs, specifically from a sustainability and biodegradation perspective, also considering the final intended application and ultimate waste management
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