1,154 research outputs found

    A test of the somnolent mentation theory and the cognitive shuffle insomnia treatment

    Get PDF
    Insomnia affects about 33% of Americans according to Harvey & Tang (2003) who called for new cognitive treatments. We will report preliminary results from a test of (a) the Somnolent Mentation theory (SMT) of sleep onset (SO) and (b) a new cognitive treatment for insomnia, the cognitive shuffle (CS), derived from the SMT (Beaudoin, 2013, 2014). According to SMT, incoherent mentation characteristic of SO is not merely a side-effect of the SO period but promotes it, meaning it is somnolent. The SMT identifies several types of insomnolent mentation, which involve sense making (e.g., problem solving). SMT postulates counter-insomnolent mentation, thought patterns that interfere with insomnolent mentation. The CS is predicted to be both somnolent and counter-insomnolent (super-somnolent). Participants either engage in constructive worry Carney & Waters (2006) or in the CS using SomnoTest an iOS app developed by CogSci Apps Corp. (led by Beaudoin) based on mySleepButton®.&nbsp

    Storage and recall of weak coherent optical pulses with an efficiency of 25%

    Full text link
    We demonstrate experimentally a quantum memory scheme for the storage of weak coherent light pulses in an inhomogeneously broadened optical transition in a Pr^{3+}: YSO crystal at 2.1 K. Precise optical pumping using a frequency stable (about 1kHz linewidth) laser is employed to create a highly controllable Atomic Frequency Comb (AFC) structure. We report single photon storage and retrieval efficiencies of 25%, based on coherent photon echo type re-emission in the forward direction. The coherence property of the quantum memory is proved through interference between a super Gaussian pulse and the emitted echo. Backward retrieval of the photon echo emission has potential for increasing storage and recall efficiency.Comment: 5,

    Serial diverse imagining task: A new remedy for bedtime complaints of worrying and other sleep-disruptive mental activity

    Get PDF
    Introduction: A racing mind, worries, and uncontrollable thoughts are common bedtime complaints among poor sleepers. Beaudoin created a Serial Diverse Imagining task (SDIT) that can be used at bedtime to divert attention away from sleep interfering thoughts, An app randomly presents recordings of relatively concrete words one at a time with an 8-second interval between recordings during which the person creates and maintains a mental image of the word until the next recording prompts the next image and so on. Our study is an experimental test of SDIT compared to the standard treatment of Structured Problem-solving (SP) and to the combination of both treatments. A key feature of SP is that it must be done earlier than bedtime and requires about 15 minutes to do it.  SDIT, which is done at bedtime, does not have those constraints.  Method: 154 university students (137 female) who complained of excessive cognitive pre-sleep arousal were randomly assigned to receive SDIT, SP, or both.  At baseline, they completed Pre-Sleep Arousal Scale (Somatic and Cognitive), Sleep Quality Scale, Glasgow Sleep Effort Scale and Sleep Hygiene Index.  Depending on the measure, participants redid it one week and/or one month after starting the intervention.  (They also completed sleep diaries and appraisals of the interventions, which are omitted due to space). Results: Repeated measures ANOVAs indicated that cognitive and somatic pre-sleep arousal , sleep effort, and sleep quality improved significantly relative to baseline (p  < .001; Partial η2 = .43 to .71) even though sleep hygiene worsened ( p  < .001; Partial η2 =  .23). The latter finding is not unexpected because the baseline was done at the start of the academic term before the onset of academic pressures. The fact that we found sleep and arousal improvements in this context are notable. Conclusion: Beaudoin’s Serial Diverse  Imagining Task (SDIT) was as effective as Structured Problem-Solving (SP) in reducing pre-sleep arousal, sleep effort, and poor sleep quality.  One advantage of SDIT is that it can be done at bedtime, unlike SP.&nbsp

    Characterisation of a high pH cement backfill for the geological disposal of nuclear waste: The Nirex Reference Vault Backfill

    Get PDF
    In a conceptual UK geological disposal facility for nuclear waste within a high-strength, crystalline geology, a cement-based backfill material, known as Nirex Reference Vault Backfill (NRVB), will be used to provide a chemical barrier to radionuclide release. The NRVB is required to have specific properties to fulfil the operational requirements of the geological disposal facility (GDF); these are dependent on the chemical and physical properties of the cement constituent materials and also on the water content. With the passage of time, the raw materials eventually used to synthesise the backfill may not be the same as those used to formulate it. As such, there is a requirement to understand how NRVB performance may be affected by a change in raw material supply. In this paper, we present a review of the current knowledge of NRVB and results from a detailed characterisation of this material, comparing the differences in performance of the final product when different raw materials are used. Results showed that minor differences in the particle size, surface area and chemical composition of the raw material had an effect on the workability, compressive strength, the rate of hydration and the porosity, which may influence some of the design functions of NRVB. This study outlines the requirement to fully characterise cement backfill raw materials prior to use in a geological disposal facility and supports ongoing assessment of long-term post-closure safety

    A new stylolite classification scheme to estimate compaction and local permeability variations

    Get PDF
    We modeled the geometrical roughening of bedding-parallel, mainly layer-dominated stylolites in order to understand their structural evolution, to present an advanced classification of stylolite shapes and to relate this classification to chemical compaction and permeability variations at stylolites. Stylolites are rough dissolution seams that develop in sedimentary basins during chemical compaction. In the Zechstein 2 carbonate units, an important lean gas reservoir in the southern Permian Zechstein basin in Germany, stylolites influence local fluid flow, mineral replacement reactions and hence the permeability of the reservoir. Our simulations demonstrate that layer-dominated stylolites can grow in three distinct stages: an initial slow nucleation phase, a fast layer-pinning phase and a final freezing phase if the layer is completely dissolved during growth. Dissolution of the pinning layer and thus destruction of the stylolite's compaction tracking capabilities is a function of the background noise in the rock and the dissolution rate of the layer itself. Low background noise needs a slower dissolving layer for pinning to be successful but produces flatter teeth than higher background noise. We present an advanced classification based on our simulations and separate stylolites into four classes: (1) rectangular layer type, (2) seismogram pinning type, (3) suture/sharp peak type and (4) simple wave-like type. Rectangular layer type stylolites are the most appropriate for chemical compaction estimates because they grow linearly and record most of the actual compaction (up to 40 mm in the Zechstein example). Seismogram pinning type stylolites also provide good tracking capabilities, with the largest teeth tracking most of the compaction. Suture/sharp peak type stylolites grow in a non-linear fashion and thus do not record most of the actual compaction. However, when a non-linear growth law is used, the compaction estimates are similar to those making use of the rectangular layer type stylolites. Simple wave-like stylolites are not useful for compaction estimates, since their growth is highly non-linear with a very low growth exponent. In the case where sealing material is collected at the tooth during dissolution, stylolites can act as barriers for local fluid flow as they intensify sealing capabilities of pinning layers. However, the development of teeth and spikes offsets and thus destroys continuous stylolite seams so that the permeability across the stylolite becomes very heterogeneous and they are no continuous barriers. This behavior is best shown in rectangular layer and seismogram pinning type stylolites that develop efficient fluid barriers at teeth tips but destroy sealing capabilities of layers by offsetting them at the flank, leading to a permeability anisotropy along 2-D stylolite planes. Suture/sharp peak stylolites can create fluid barriers if they collect enough sealing material. However, if the collecting material does not seal or if spikes offset the sealing material the stylolite leaks. We propose that our classification can be used to realistically estimate chemical compaction in reservoirs and gives an indication on how heterogeneous the permeability of stylolites can be

    Photothermal infrared thermography applied to the identification of thin layer thermophysical properties

    Get PDF
    Abstract: The aim of the present work is the thermal non-destructive characterisation of layers at the surface of metals. The sample is sinusoidally heated by means of an argon ion laser and a focal plane array infrared camera (CEDIP IRC 320-4 LW) is used to measure the temperature variations at the surface of the layer. A numerical lock-in procedure allows the detection of very weak temperature variations at the surface of the sample, down to a few mK when working from the acquisition of hundreds of images, yielding amplitude and absolute phase maps for modulation frequencies ranging from 0.1 Hz to 1000 Hz. An inverse procedure uses the Gauss-Newton parameter estimation method, in order to identify the thermal conductivity and the optical absorption coefficient of the layer. Confidence intervals on the parameters can also be estimated by the inverse procedure. More particular attention is devoted to the study of the sensitivity coefficients, as functions of the frequency range and of the radial range along the profiles, in order to optimise the identification procedure

    Pooled analysis of higher versus lower blood pressure targets for vasopressor therapy septic and vasodilatory shock

    Get PDF
    PURPOSE: Guidelines for shock recommend mean arterial pressure (MAP) targets for vasopressor therapy of at least 65 mmHg and, until recently, suggested that patients with underlying chronic hypertension and atherosclerosis may benefit from higher targets. We conducted an individual patient-data meta-analysis of recent trials to determine if patient variables modify the effect of different MAP targets. METHODS: We searched the MEDLINE, EMBASE, and Cochrane Central Register of Controlled Trials for randomized controlled trials of higher versus lower blood pressure targets for vasopressor therapy in adult patients in shock (until November 2017). After obtaining individual patient data from both eligible trials, we used a modified version of the Cochrane Collaboration\u27s instrument to assess the risk of bias of included trials. The primary outcome was 28-day mortality. RESULTS: Included trials enrolled 894 patients. Controlling for trial and site, the OR for 28-day mortality for the higher versus lower MAP targets was 1.15 (95% CI 0.87-1.52). Treatment effect varied by duration of vasopressors before randomization (interaction p = 0.017), but not by chronic hypertension, congestive heart failure or age. Risk of death increased in higher MAP groups among patients on vasopressors > 6 h before randomization (OR 3.00, 95% CI 1.33-6.74). CONCLUSIONS: Targeting higher blood pressure targets may increase mortality in patients who have been treated with vasopressors for more than 6 h. Lower blood pressure targets were not associated with patient-important adverse events in any subgroup, including chronically hypertensive patients
    • …
    corecore