895 research outputs found

    Comparison of Secondhand Smoke Exposure in Minority and Non-minority Children with Asthma

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    Objective—Determine if secondhand smoke exposure (SHSE) is related to asthma-related functional morbidity by examining racial/ethnic differences in Non-Latino White (NLW), African American, and Latino families and whether racial/ethnic SHSE differences across families persist when accounting for smoking factors. Methods—Participants were 305 caregiver smokers of children with asthma. Two passive dosimeters measured SHS: one in the home and one worn by the child. Results—Higher SHSE was related to greater asthma-related functional morbidity. African Americans had higher levels of home SHSE than Latinos (p = .003) or NLWs (p = .021). SHSE as assessed by the child worn dosimeter did not differ across race/ethnicity. African American families were less likely to report a household smoking ban (46.4%) compared to Latinos (79.2%) and NLWs (67.9%; p \u3c .05). African Americans were less likely to report having two or more smokers in the home (37.2%) compared to NLWs (53.6%; p \u3c .05). NLWs reported the highest number of cigarettes smoked daily (Mdn = 15.00) compared to Latinos (Mdn = 10.00; p = .001) and African Americans (Mdn = 10.00; p \u3c .001). SHS home exposure levels were regressed on race/ethnicity and relevant covariates. Household smoking ban (p \u3c .001) and only one smoker in the home (p = .005) were associated with lower levels of SHS in the home; race/ethnicity was not significant. Conclusions—Differences in SHSE across race/ethnicity exist among children with asthma, possibly due to differential presence of a household smoking ban and number of smokers in the home

    Fatalism and Future Contingents

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    In this paper I address issues related to the problem of future contingents and the metaphysical doctrine of fatalism. Two classical responses to the problem of future contingents are the third truth value view and the all-false view. According to the former, future contingents take a third truth value which goes beyond truth and falsity. According to the latter, they are all false. I here illustrate and discuss two ways to respectively argue for those two views. Both ways are similar in spirit and intimately connected with fatalism, in the sense that they engage with the doctrine of fatalism and accept a large part of a standard fatalistic machinery

    Using the Intervention Mapping and Behavioral Intervention Technology Frameworks: Development of an mHealth Intervention for Physical Activity and Sedentary Behavior Change

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    Few interventions to promote physical activity (PA) adapt dynamically to changes in individuals' behavior. Interventions targeting determinants of behavior are linked with increased effectiveness and should reflect changes in behavior over time. This article describes the application of two frameworks to assist the development of an adaptive evidence-based smartphone-delivered intervention aimed at influencing PA and sedentary behaviors (SB). Intervention mapping was used to identify the determinants influencing uptake of PA and optimal behavior change techniques (BCTs). Behavioral intervention technology was used to translate and operationalize the BCTs and its modes of delivery. The intervention was based on the integrated behavior change model, focused on nine determinants, consisted of 33 BCTs, and included three main components: (1) automated capture of daily PA and SB via an existing smartphone application, (2) classification of the individual into an activity profile according to their PA and SB, and (3) behavior change content delivery in a dynamic fashion via a proof-of-concept application. This article illustrates how two complementary frameworks can be used to guide the development of a mobile health behavior change program. This approach can guide the development of future mHealth programs

    MAD-AIR

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    Forced air heating ard air corditioning duct systems in residential housing have been largely overlcoked in house diagnostics. Even the building is itself a part of the overall ir distribution system. When a duct system fails, it can have some serious effects on the home. Proper air flow within the corditioned space is as important as the air flow within the duct line. Failure of a duct system or even the closing of the interior dcors can create pressure differentials both within ard across the building envelope when the heating and air conditioning fan is in operation. These failures may cause increased energy usage, poor indoor air quality and even promote multiple moisture problems

    Mechanical Air Distribution and Interacting Relationships

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    It has been determined from extensive testing conducted between May 1987 and May 1988, in the hot and humid climate of central Florida, that pressure differences within the envelope of residential housing exists. These can range from near neutral to pressures, either positive or negative, as great as 0.24" W.C. (60 pascals). Reasons sighted and discussed in this paper include duct system design, duct system failure, airtightness of the residence and human interactions. This testing further reveals that one of the largest driving forces in air change rates can be attributed to mechanically induced infiltration and exfiltration. Airtightness can also drastically affect this pressure difference within the envelope. In conclusion, the effects of these pressure differentials on energy consumption, indoor air quality, comfort, and degradation of building materials will be discussed. Possible solutions and practical field test protocol to correct these ill effects both in new and existing residential housing will be covered

    On-farm food loss in northern and central California: Results of field survey measurementsAuthor links open overlay panel

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    Prevailing estimates of food loss at the farm level are sparse and often reliant upon grower surveys. A more comprehensive review of food loss at the farm level using field surveys is required to gain an adequate understanding of the depth of this issue. This paper details the results of 123 in-field surveys and 18 in-depth interviews of 20 different, hand-harvested field crops performed largely on midsize to large conventional farms in northern and central California. We also provide estimates of the percentage of fields that go unharvested, commonly known as walk-by fields. The results show that food loss is highly variable and largely dependent upon the crop, variety, market price, labor costs, grower practices, buyer specifications, and environmental conditions. On average, we found 11,299 kg/ha of food loss at the farm level, which equates to 31.3% of the marketed yield. When walk-by losses are included, this figure rises to 33.7%. Our paper also demonstrates that grower estimates are typically very unreliable for estimating on-farm food losses. Actual, measured edible food loss exceeded growers’ estimates by a median value of 157%. Strategies to utilize this lost produce could play a significant role in reducing the impact of agriculture on the environment and providing food for the rapidly growing population

    Towards attosecond high-energy electron bunches : controlling self-injection in laser wakefield accelerators through plasma density modulation

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    Self-injection in a laser-plasma wakefield accelerator (LWFA) is usually achieved by increasing the laser intensity until the threshold for injection is exceeded. Alternatively, the velocity of the bubble accelerating structure can be controlled using plasma density ramps, reducing the electron velocity required for injection. We present a model describing self-injection in the short bunch regime for arbitrary changes in the plasma density. We derive the threshold condition for injection due to a plasma density gradient, which is confirmed using particle-in-cell (PIC) simulations that demonstrate injection of sub-femtosecond bunches. It is shown that the bunch charge, bunch length and separation of bunches in a bunch train can be controlled by tailoring the plasma density profile

    Ultrafast photon-photon interaction in a strongly coupled quantum dot-cavity system

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    We study dynamics of the interaction between two weak light beams mediated by a strongly coupled quantum dot-photonic crystal cavity system. First, we perform all optical switching of a weak continuous-wave signal with a pulsed control beam, and then perform switching between two pulsed beams (40ps pulses) at the single photon level. Our results show that the quantum dot-nanocavity system creates strong, controllable interactions at the single photon level
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