886 research outputs found
Cavity-enhanced optical detection of carbon nanotube Brownian motion
Optical cavities with small mode volume are well-suited to detect the
vibration of sub-wavelength sized objects. Here we employ a fiber-based,
high-finesse optical microcavity to detect the Brownian motion of a freely
suspended carbon nanotube at room temperature under vacuum. The optical
detection resolves deflections of the oscillating tube down to 50pm/Hz^1/2. A
full vibrational spectrum of the carbon nanotube is obtained and confirmed by
characterization of the same device in a scanning electron microscope. Our work
successfully extends the principles of high-sensitivity optomechanical
detection to molecular scale nanomechanical systems.Comment: 14 pages, 11 figure
Effects of intervention upon precompetition state anxiety in elite junior tennis players: The relevance of the matching hypothesis
Reproduced with permission of publisher from:
Terry, P., Coakley, L., & Karageorghis, C. Effects of intervention upon precompetition state anxiety in elite junior tennis players: the relevance of the matching hypothesis. Perceptual and Motor Skills, 1995, 81, 287-296. © Perceptual and Motor Skills 1995The matching hypothesis proposes that interventions for anxiety should be matched to the modality in which anxiety is experienced. This study investigated the relevance of the matching hypothesis for anxiety interventions in tennis. Elite junior tennis players (N = 100; Age: M = 13.9 yr., SD = 1.8 yr.) completed the Competitive State Anxiety Inventory-2 before and after one of four randomly assigned intervention strategies approximately one hour prior to competition at a National Junior Championship. A two-factor multivariate analysis of variance (group x time) with repeated measures on the time factor gave no significant main effect by group but indicated significant reductions in somatic anxiety and cognitive anxiety and a significant increase in self-confidence following intervention. A significant group by time interaction emerged for self-confidence. The results question the need to match intervention strategy to the mode of anxiety experienced
Retrieving the structure of probabilistic sequences of auditory stimuli from EEG data
Using a new probabilistic approach we model the relationship between
sequences of auditory stimuli generated by stochastic chains and the
electroencephalographic (EEG) data acquired while 19 participants were exposed
to those stimuli. The structure of the chains generating the stimuli are
characterized by rooted and labeled trees whose leaves, henceforth called
contexts, represent the sequences of past stimuli governing the choice of the
next stimulus. A classical conjecture claims that the brain assigns
probabilistic models to samples of stimuli. If this is true, then the context
tree generating the sequence of stimuli should be encoded in the brain
activity. Using an innovative statistical procedure we show that this context
tree can effectively be extracted from the EEG data, thus giving support to the
classical conjecture.Comment: 16 pages, 7 figure
A note on the invariant distribution of a quasi-birth-and-death process
The aim of this paper is to give an explicit formula of the invariant
distribution of a quasi-birth-and-death process in terms of the block entries
of the transition probability matrix using a matrix-valued orthogonal
polynomials approach. We will show that the invariant distribution can be
computed using the squared norms of the corresponding matrix-valued orthogonal
polynomials, no matter if they are or not diagonal matrices. We will give an
example where the squared norms are not diagonal matrices, but nevertheless we
can compute its invariant distribution
Prostate cancer-specific PET radiotracers : a review on the clinical utility in recurrent disease
Prostate cancer-specific positron emission tomography (pcPET) has been shown to detect sites of disease recurrence at serum prostate-specific antigen (PSA) levels that are lower than those levels detected by conventional imaging. Commonly used pcPET radiotracers in the setting of biochemical recurrence are reviewed including carbon 11/fludeoxyglucose 18 (F-18) choline, gallium 68/F-18 prostate-specificmembrane antigen (PSMA), and F-18 fluciclovine. Review of the literature generally favors PSMA-based agents for the detection of recurrence as a function of low PSA levels. Positive gallium 68/F-18PSMA positron emission tomography/computed tomography scans detected potential sites of recurrence in a median 51.5% of patients when PSA level is 2.0 ng/mL. Review of carbon 11/fludeoxyglucose 18 (F-18) choline and F-18 fluciclovine data commonly demonstrated lower detection rates for each respective PSA cohort, although with some important caveats, despite having similar operational characteristics to PSMA-based imaging. Sensitive pcPET imaging has provided new insight into the early patterns of disease spread, which has prompted judicious reconsideration of additional local therapy after either prostatectomy, definitive radiation therapy, or postprostatectomy radiation therapy. This review discusses the literature, clinical utility, availability, and fundamental understanding of pcPET imaging needed to improve clinical practice. (C) 2017 The Authors. Published by Elsevier Inc. on behalf of American Society for Radiation Oncology
Using metamemory measures and memory tests to estimate eyewitness free recall performance
Using a mock witness methodology, we investigated the predictive value of metamemory measures and objective memory tests as indicators of eyewitness free recall performance. Participants (n = 208) first completed a metamemory assessment that included assessments of self-rated memory capacity, memory development and use of strategies. In a separate session, participants watched a mock-crime video and provided a free recall account, followed by one out of four independent memory tests (i.e., free recall, cued recall, face recognition and general knowledge). Accuracy, amount of details reported, confidence and over/underconfidence in the eyewitness free recall were the main dependent variables. Results indicated three main findings: (1) subjective assessments of memory capacity were not related to eyewitness free recall performance; (2) although individual confidence and over/underconfidence was somewhat stable across different memory tests, accuracy was less stable; and (3) individuals with higher self-rated memory capacity had a slightly stronger confidence-accuracy relation in free recall. These results are discussed with respect to metamemory assessments and performance stability across memory tests of different domains
Overcoming Postcommunist Labour Weakness: Attritional and Enabling Effects of MNCs in Central and Eastern Europe
Based on micro-level analysis of the developments in the steel sector in Poland, Romania and Slovakia, this paper examines the effects of multinational corporations (MNCs) on labour unions in Central and Eastern Europe. It makes a three-fold argument. First, it shows that union weakness can be attributed to unions’ strategies during the restructuring and privatization processes of postcommunist transition. Consequently, tactics used for union regeneration in the West are less applicable to CEE. Rather, the overcoming of postcommunist legacy is linked to the power of transnational capital. Through attritional and enabling effects, ownership by MNCs forces the unions to focus their efforts on articulating workers’ interests. The paper examines the emerging system of industrial relations in the sector and explores the development of the capabilities needed to overcome postcommunist legacies
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