Performance of Dual Photoelectric/Ionization Smoke Alarms in Full-Scale Fire Tests

Data from two full-scale residential smoke alarm fire test series were analyzed to estimate the performance of dual sensor photoelectric/ionization alarms as compared to co-located individual photoelectric and ionization alarms. Dual alarms and aggregated photoelectric and ionization alarm responses were used to estimate dual alarm performance. It was observed that dual alarms with equivalent or higher sensitivity settings performed better than individual photoelectric or ionization alarms over a range of flaming and smoldering fire scenarios. In one test series, dual alarms activated 539 s faster than ionization alarms and 79 s faster than photoelectric alarms on average. In another test series, individual alarm sensor outputs were calibrated against a reference smoke source in terms of light obscuration over a path length (percent smoke obscuration per unit length) so that alarm thresholds could be defined by the sensor outputs. In that test series, dual alarms, with individual sensor sensitivities equal to their counterpart alarm sensitivities, activated 261 s faster on average than ionization alarms (with sensitivity settings of 4.3%/m smoke obscuration for the ionization sensors) and 35 s faster on average than the photoelectric alarms (with sensitivity settings of 6.6%/m, for the photoelectric sensors.) In cases where an ionization sensor was the first to reach the alarm threshold, the dual alarm activated 67 s faster on average than the photoelectric alarm. While in cases were a photoelectric sensor was the first to reach the alarm threshold, the dual alarm activated 523 s faster on average than the ionization alarm. Over a range of ionization sensor settings examined, dual alarm response was insensitive to the ionization sensor setting for initially smoldering fires and fires with the bedroom door closed, while dual alarm response to the kitchen fires was very sensitive to the ionization sensor setting. Tests conducted in the National Institute of Standards and Technology (NIST) fire emulator/detector evaluator showed that the ionization sensors in off-the-shelf ionization alarms and dual alarms span a range of sensitivity settings. While there appears to be no consensus on sensitivity setting for ionization sensors, it may be desirable to tailor sensor sensitivities in dual alarms for specific applications, such as near kitchens where reducing nuisance alarms may be a goal, or in bedrooms where higher smoke sensitivity may be a goal.     

IGSTK: an open source software toolkit for image-guided surgery

Image-guided surgery applies leading-edge technology and clinical practices to provide better quality of life to patients who can benefit from minimally invasive procedures. Reliable software is a critical component of image-guided surgical applications, yet costly expertise and technology infrastructure barriers hamper current research and commercialization efforts in this area. IGSTK applies the open source development and delivery model to this problem. Agile and component-based software engineering principles reduce the costs and risks associated with adopting this new technology, resulting in a safe, inexpensive, robust, shareable, and reusable software infrastructure.     

Laser-induced fluorescence detection of atmospheric NO2 with a commercial diode laser and a supersonic expansion

Routine observations of atmospheric NO2 at concentrations ranging from 0.1 to 100 parts per billion are needed for air quality monitoring and for the evaluation of photochemical models. We have designed, constructed, and field tested a relatively inexpensive and specific NO2 sensor using laser-induced fluorescence. The instrument combines a commercial cw external-cavity tunable diode laser (640 nm) and a continuous supersonic expansion. The total package is completely automated, has a modest size of 0.5 m3 and 118 kg, and could be manufactured at competitive price, with the current generation of instruments. The sensitivity of the instrument is 145 part per trillion by volume min(-1) (signal-to-noise ratio of 2), which is more than adequate for monitoring purposes.     

Patients' trust in their physicians: effects of choice, continuity, and payment method

OBJECTIVE: To evaluate the extent to which physician choice, length of patient-physician relationship, and perceived physician payment method predict patients' trust in their physician. DESIGN: Survey of patients of physicians in Atlanta, Georgia. PATIENTS: Subjects were 292 patients aged 18 years and older. MEASUREMENTS AND MAIN RESULTS: Scale of patients' trust in their physician was the main outcome measure. Most patients completely trusted their physicians "to put their needs above all other considerations" (69%). Patients who reported having enough choice of physician (p < .05), a longer relationship with the physician (p < .001), and who trusted their managed care organization (p < .001) were more likely to trust their physician. Approximately two thirds of all respondents did not know the method by which their physician was paid. The majority of patients believed paying a physician each time a test is done rather than a fixed monthly amount would not affect their care (72.4%). However, 40.5% of all respondents believed paying a physician more for ordering fewer than the average number of tests would make their care worse. Of these patients, 53.3% would accept higher copayments to obtain necessary medical tests. CONCLUSIONS: Patients' trust in their physician is related to having a choice of physicians, having a longer relationship with their physician, and trusting their managed care organization. Most patients are unaware of their physician's payment method, but many are concerned about payment methods that might discourage medical use.     

Rotation distance is fixed-parameter tractable

Rotation distance between trees measures the number of simple operations it takes to transform one tree into another. There are no known polynomial-time algorithms for computing rotation distance. In the case of ordered rooted trees, we show that the rotation distance between two ordered trees is fixed-parameter tractable, in the parameter, k, the rotation distance. The proof relies on the kernelization of the initial trees to trees with size bounded by 5k.     

Should hand actions be observed when learning hand motor skills from instructional animations?

This study investigated whether the effectiveness of learning a hand-motor task through an instructional animation required observation of the hands or not. Cognitive load theory was used to predict that both animated conditions (with and without hands) would be equally effective, and that both animations would be superior to an equivalent static graphics presentation. 36 adults were randomly assigned to three groups (With-hands animation, No-hands animation, Statics graphics) and were required to learn how to tie two knots. Test results confirmed that both animations led to superior learning compared to the static presentation. However, the With-hands animation strategy had a further advantage in that it had higher instructional efficiency than the No-hands animation.     

Nodular lymphocyte predominance Hodgkin's disease. A distinct clinicopathological entity

This article reviews the evidence that the nodular form of lymphocyte predominance Hodgkin's disease ("nodular paragranuloma") should be recognised as a distinct clinico-pathological entity. The disease is characterised histologically by very large primary lymphoid follicles, containing polytypic small B lymphocytes and extensive meshworks of follicular dendritic cells. The "L and H" or "popcorn" cells scattered within the nodules show clear differences from classical Reed-Sternberg cells, both in their cytological appearance and in their marker profile, being frequently negative for CD15 and for the EBV genome, but often positive for B cell antigens, CD45 (leucocyte common antigen), CDw75 (LN1), epithelial membrane antigen (EMA) and J chain. These findings suggest that L and H cells may be Ig-synthesising monoclonal B cells. Nodular lymphocyte predominance Hodgkin's disease pursues a much more indolent courses that classical Hodgkin's disease, and long term survival is common. It has other distinctive clinical features, e.g. a unimodal age distribution, a predilection to involve single lymph nodes, and a very low incidence of thymic involvement. There is a tendency for diffuse large cell non-Hodgkin's lymphoma, usually of B cell type, to develop during the course of the disease. This type of Hodgkin's disease thus has many features that distinguish it from the nodular sclerosis and mixed cellularity varieties, and it is hoped that future studies will gather more information on its clinical behavior and on the nature of the putative neoplastic cells, as well as exploring different protocols for its treatment.     

Recognition memory for novel stimuli: The structural regularity hypothesis.

Early studies of human memory suggest that adherence to a known structural regularity (e.g., orthographic regularity) benefits memory for an otherwise novel stimulus (e.g., G. A. Miller, 1958). However, a more recent study suggests that structural regularity can lead to an increase in false-positive responses on recognition memory tests (B. W. A. Whittlesea & L. D. Williams, 1998). In the present study the authors attempted to identify the circumstances under which structural regularity benefits old-new discrimination and those under which it leads to an increase in false-positive responses. The highly generalizable tendency shown here is for structural regularity to benefit old-new discrimination. The increase in false-positive responses for structurally regular novel items may be limited to situations in which regularity is confounded with similarity to studied items. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Increased apoptosis accompanies neoplastic development in the human colorectum

A disturbance in the balance between cell proliferation and cell loss, or apoptosis, may underlie neoplastic development. Therefore, we determined spontaneous apoptotic and proliferative rates in normal, hyperplastic, adenomatous, and malignant colorectal epithelia. In paired sections, DNA strand breaks were detected using the terminal deoxynucleotidyltransferase-mediated dUTP nick-end labeling assay, and apoptotic cells were also identified in H&E-stained slides by morphological criteria. Cell proliferation, bcl-2, and p53 expression were analyzed using specific monoclonal antibodies. In normal mucosa, luminal epithelial cells demonstrated higher rates of apoptosis compared to cells in the proliferative zone. Neoplastic transformation was associated with a significant increase in rates of apoptosis and proliferation. However, apoptosis, but not proliferation, decreased at the adenoma-to-carcinoma transition coincident with expression of mutant p53. In carcinomas, both mutant p53 and bcl-2 protein levels were associated with attenuated apoptotic rates. In conclusion, apoptosis is an important regulator of growth in normal and neoplastic colorectal epithelia. Increased apoptosis and proliferation accompany neoplastic transformation, suggesting that an alteration in apoptotic rates is an important event in colorectal carcinogenesis. Furthermore, the imbalance in these processes found in carcinomas may facilitate tumor growth and progression.