Bayesian inversion of synthetic AVO data to assess fluid and shale content in sand-shale media

Reservoir characterization of sand-shale sequences has always challenged geoscientists due to the presence of anisotropy in the form of shale lenses or shale layers. Water saturation and volume of shale are among the fundamental reservoir properties of interest for sand-shale intervals, and relate to the amount of fluid content and accumulating potentials of such media. This paper suggests an integrated workflow using synthetic data for the characterization of shaley-sand media based on anisotropic rock physics (T-matrix approximation) and seismic reflectivity modelling. A Bayesian inversion scheme for estimating reservoir parameters from amplitude vs. offset (AVO) data was used to obtain the information about uncertainties as well as their most likely values. The results from our workflow give reliable estimates of water saturation from AVO data at small uncertainties, provided background sand porosity values and isotropic overburden properties are known. For volume of shale, the proposed workflow provides reasonable estimates even when larger uncertainties are present in AVO data

A perspective on SIDS pathogenesis. The hypotheses: plausibility and evidence

Several theories of the underlying mechanisms of Sudden Infant Death Syndrome (SIDS) have been proposed. These theories have born relatively narrow beach-head research programs attracting generous research funding sustained for many years at expense to the public purse. This perspective endeavors to critically examine the evidence and bases of these theories and determine their plausibility; and questions whether or not a safe and reasoned hypothesis lies at their foundation. The Opinion sets specific criteria by asking the following questions: 1. Does the hypothesis take into account the key pathological findings in SIDS? 2. Is the hypothesis congruent with the key epidemiological risk factors? 3. Does it link 1 and 2? Falling short of any one of these answers, by inference, would imply insufficient grounds for a sustainable hypothesis. Some of the hypotheses overlap, for instance, notional respiratory failure may encompass apnea, prone sleep position, and asphyxia which may be seen to be linked to co-sleeping. For the purposes of this paper, each element will be assessed on the above criteria

HealthCall for the smartphone: technology enhancement of brief intervention in HIV alcohol dependent patients

Background: Heavy drinking jeopardizes the health of patients in HIV primary care. In alcohol dependent patients in HIV primary care, a technological enhancement of brief intervention, HealthCall administered via interactive voice response (HealthCall-IVR) was effective at reducing heavy drinking. The smartphone offered a technology platform to improve HealthCall. Methods: Working with input from patients, technology experts, and HIV clinic personnel, we further developed HealthCall, harnessing smartphone technological capacities (HealthCall-S). In a pilot study, we compared rates of HealthCall-S daily use and drinking outcomes in 41 alcohol dependent HIV-infected patients with the 43 alcohol dependent HIV-infected patients who used HealthCall-IVR in our previous efficacy study. Procedures, clinic, personnel, and measures were largely the same in the two studies, and the two groups of patients were demographically similar (~90% minority). Results: Pilot patients used HealthCall-S a median of 85.0% of the 60 days of treatment, significantly greater than the corresponding rate (63.8%) among comparison patients using HealthCall-IVR (p < .001). Mean end-of-treatment drinks per drinking day was similar in the two groups. Patients were highly satisfied with HealthCall-S (i.e., 92% reported that they liked using HealthCall-S). Conclusions: Among alcohol dependent patients in HIV primary care, HealthCall delivered via smartphone is feasible, obtains better patient engagement than HealthCall-IVR, and is associated with decreased drinking. In HIV primary care settings, HealthCall-S may offer a way to improve drinking outcomes after brief intervention by extending patient engagement with little additional demands on staff time

Full and Partial 5-HT 1A Receptor Agonists Disrupt Learning and Performance in Rats

ABSTRACT As a means of characterizing the role of 5-hydroxytryptamine (5-HT 1A ) receptors in learning, a full 5-HT 1A receptor agonist, 8-hydroxy-dipropylaminotetralin (8-OH-DPAT), was administered both alone and in combination with two partial agonists (buspirone and 1-(2-methoxyphenyl)-4-[4-(2-phthalimido)butyl] piperazine hydrobromide ) and a 5-HT 1A receptor antagonist (p-MPPI) to rats responding under a multiple schedule of repeated acquisition and performance of response sequences. In addition, the effects of another 5-HT 1A receptor agonist, (LY228729), were also studied under this same procedure. When administered alone, both 8-OH-DPAT (0.1-3.2 mg/ kg) and LY228729 (0.32-3.2 mg/kg) dose dependently decreased overall response rate and increased the percentage of errors in the acquisition and performance components. At the doses of each drug tested, both buspirone (0.32 or 1 mg/kg) and (1 or 3.2 mg/kg) also decreased overall response rate and increased the percentage of errors. However, the effects of these drugs differed across behavioral components and dependent measures. The effects of buspirone and NAN-190 on rate and accuracy were also different when they were administered in combination with 8-OH-DPAT. In contrast, p-MPPI (3.2 or 10 mg/kg) had little or no effect when administered alone and antagonized the effects of 8-OH-DPAT; shifting the dose-effect curves for both response rate and the percentage of errors in both components to the right. Taken together, these results indicate that complex behaviors in rats are sensitive to disruption by drugs with both full and partial 5-HT 1A receptor agonist properties, and that the effects of partial 5-HT 1A receptor agonists on learning may be different depending on their efficacy at pre-and postsynaptic 5-HT 1A receptors. A substantial problem in establishing the functional significance of 5-hydroxytryptamine (5-HT 1A ) receptors in the acquisition of behavior (learning) has been the inability of various animal models to distinguish between the disruptive effects of 5-HT 1A receptor agonists on learning and their disruptive effects on other behaviors such as locomotor activity. In a repeated acquisition study comparing the disruptive effects of several benzodiazepines with the effects of 8-OH-DPAT and buspirone in rats and monkeys

Design characteristics, primary stability and risk of fracture of orthodontic mini-implants: Pilot scan electron microscope and mechanical studies

Objective: Orthodontic mini-implants (OMIs) are increasingly used in orthodontics but can fail for various reasons. This study investigates the effects of OMI design characteristics on the mechanical properties in artificial bone. Material and Methods: Twelve self-drilling OMIs (2 small, 6 medium, 4 large) from 8 manufacturers were tested for their primary stability in simulated medium-high cancellous bone and the risk to fracture in high-density methacrylate blocks. For the assessments of the maximum insertion torque (IT) and torsional fracture (TF) 5 of each OMI were used and for the pull-out strength (POS) 10. The OMIs were inserted with a torque screwdriver (12 sec/360°) until the bottom at 8 mm depth was reached. OMI designs were analyzed with a scan electron microscope (SEM). Results: SEM images revealed a great variation in product refinement. In the whole sample, a cylindrical OMI shape was associated with higher POS (p<0.001) but lower IT (p=0.002) values. The outer and inner OMI diameters were design characteristics well correlated with POS, IT and TF values (ranging from 0.601 to 0.961). Greater thread depth was related to greater POS values (r= 0.628), although OMIs with similar POS values may have different IT values. Thread depth and pitch had some impact on POS. TF depended mainly on the OMI inner (r= 0.961) and outer diameters (r=0.892). A thread depth to outer diameter ratio close to 40% increased TF risk. Conclusion: Although at the same insertion depth the OMI outer and inner diameters are the most important factors for primary stability, other OMI design characteristics (cylindrical vs. conical, thread design) may significantly affect primary stability and torsional fracture. This needs to be considered when selecting the appropriate OMI for the desired orthodontic procedures.Peer Reviewe