Previous studies have shown that dispersion of contaminant concentrations strongly depends on air inlet types. However, these studies were performed computationally,
not experimentally. Thus, the ...purpose of the current research is to obtain contaminant concentrations in a room, to perform qualitative and quantitative comparison for a wall jet (WJ) air inlet and a ceiling diffuser (CD) air inlet, and to determine more efficient inlet and outlet configuration.
Here, the effect of air inlet types in mixing ventilation was investigated in an experimental room under two conditions, with no occupant and with an occupant present north of the source. A heated mannequin, producing a total heat load of 120
W, represented an occupant. Tracer gas (99.5% propylene) concentrations were monitored automatically at 144 sampling points with a photoionization detector. Three flow rates (5.5, 3.3, and 0.9
m
3/min) were employed.
Experimental results for the 0.9
m
3/min are not reported here because concentration measurements with time in preliminary tests did not reach a stationary condition even over periods of 5
h due to dominant airflow by natural convection rather than by forced convection. Results have shown that the air inlet type is an important physical determinant to the distribution of airborne contaminant concentrations because they generate different airflow patterns and thus different spatial concentration patterns. This investigation enhanced understanding of the interactions of concentration field, airflow, and air inlet types. The findings of the study can be applied to practical areas; for example, it was shown that CD air supply system minimizes occupant exposure from hazards in office buildings, hospitals, and schools, if sources are located under ceiling diffuser inlets.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
Third-party payer systems are consistently associated with health care cost escalation. Taiwan’s single-payer, universal coverage National Health Insurance (NHI) adopted global budgeting (GB) to ...achieve cost control. This study captures ophthalmologists’ response to GB, specifically service volume changes and service substitution between low-revenue and high-revenue services following GB implementation, the subsequent Bureau of NHI policy response, and the policy impact. De-identified eye clinic claims data for the years 2000, 2005, and 2007 were analyzed to study the changes in Simple Claim Form (SCF) claims versus Special Case Claims (SCCs). The 3 study years represent the pre-GB period, post-GB but prior to region-wise service cap implementation period, and the post-service cap period, respectively. Repeated measures multilevel regression analysis was used to study the changes adjusting for clinic characteristics and competition within each health care market. SCF service volume (low-revenue, fixed-price patient visits) remained constant throughout the study period, but SCCs (covering services involving variable provider effort and resource use with flexibility for discretionary billing) increased in 2005 with no further change in 2007. The latter is attributable to a 30% cap negotiated by the NHI Bureau with the ophthalmology association and enforced by the association. This study demonstrates that GB deployed with ongoing monitoring and timely policy responses that are designed in collaboration with professional stakeholders can contain costs in a health insurance–financed health care system.
To explore demographic differences in individual, social, and environmental factors potentially related to fruit and vegetable intake.
Self-report questionnaires administered to a convenience sample ...of middle school students during regular classes.
Black and white adolescents, 11 to 15 years of age (N = 736).
Measures included self-efficacy, family dinner frequency, normative beliefs, outcome expectations, modeling, availability, preferences, snack choice, and demographics.
Chi-square, general linear models, and Poisson and linear regressions as appropriate.
Black participants reported greater social influences than did white participants, whereas white adolescents reported greater family environmental influences on fruit and vegetable intake. The oldest adolescents reported lower self-efficacy, peer modeling, family dinner frequency, and fruit and vegetable preferences compared with younger adolescents. White participants and females reported a higher preference for vegetables than did black participants and males. Regression models for self-efficacy and snack choice explained 41% and 34% of the variance, respectively. Preferences for vegetables and parental modeling were the strongest correlates of self-efficacy. Self-efficacy was the strongest correlate of snack choice.
Decreases in several factors with age highlight the importance of intervention for this age group. Future research is needed for a better understanding of the formation and modification of self-efficacy and snack choice.
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DOBA, FSPLJ, GEOZS, IJS, IMTLJ, IZUM, KILJ, KISLJ, NUK, OILJ, PILJ, PNG, SAZU, SBCE, SBJE, SIK, UILJ, UKNU, UL, UM, UPCLJ, UPUK, VSZLJ
Summary Objective The objective was to assess the effects of massage compared to guided relaxation on stress perception and well-being among older adults. Design A randomised pilot study enrolled ...adults ages 60 and older to receive 50 min, twice weekly massage therapy or guided relaxation sessions. Questionnaires were administered at pre-test (1 week before the first session) and post-test (after the last session). Setting Participants came to the University of South Carolina campus for sessions. Adults aged 60 and older were recruited from community venues and were briefly screened by telephone for contraindications. Intervention Participants ( n = 54) received 50 min massage or guided relaxation sessions twice weekly for 4 weeks. The massage included Swedish, neuromuscular, and myofascial techniques. For the relaxation group, an appropriately trained assistant read a script to guide the participant in using visualization and muscle relaxation. Main outcome measures The General Well-being Schedule is an 18-item scale with subscales measuring anxiety, depression, positive well-being, self-control, vitality, and general health. The Perceived Stress Scale is a 14-item scale assessing the degree to which situations in one's life are appraised as stressful during the past month. Results Significant improvements were found for the anxiety, depression, vitality, general health, and positive well-being subscales of the General Well-being Schedule and for Perceived Stress among the massage participants compared to guided relaxation. Conclusions Findings indicate that massage therapy enhances positive well-being and reduces stress perception among community-dwelling older adults.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
The impact of a worker's location, orientation, and activity was studied in an experimental room (2.86 m × 2.35 m × 2.86 m) at known flow rates of 5.5 m
3
/min and 3.3 m
3
/min. A person in the room, ...wearing a full-facepiece, air-supplied respirator represented a worker. Propylene tracer gas was emitted at a constant rate from a 1-m pedestal at the center of the room and a continuous air sample was drawn from a point midway between the worker's mouth and nose. Breathing zone concentration (BZC) was monitored at 12 worker locations within the room for a stationary worker. At each location, BZCs were measured separately for four worker orientations: east, west, south, and north. BZCs of a walking worker were also monitored along the path defined by the 12 worker locations used in the stationary experiments. In a separate set of experiments, area concentration was monitored to see whether the worker's activity disturbed the contaminant concentrations at a fixed sampling point located behind the source looking from the direction of air inlet (location: 1.34 m, 1.20 m, 0.45 m). The following average differences in BZC over the 12 fixed locations were observed: 43% higher for near-field than for far-field locations; 20% higher when the worker was facing the source than when facing away (p-values for all four conditions: < 0.033), and 30% higher for a moving worker than for a stationary worker (p-values for all four conditions: < 0.01). When the worker was walking, the concentration at the fixed area sampling point was generally lower than the area concentration when the worker was absent or stationary in the room, possibly due to greater mixing of room air by the worker's movement. Because a worker's activities may be irregular and complicated, incorporating them as parameters in mathematical models is often not feasible. Instead, these findings may be used to assess uncertainty or adjust exposure estimates from simple models.
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BFBNIB, GIS, IJS, KISLJ, NUK, PNG, UL, UM, UPUK, VSZLJ
Water samples were collected in mixed land-use basins draining into the Murrells Inlet estuary, SC, and in two undeveloped basins draining into North Inlet, and nutrient concentrations were measured ...and related to land use/land cover data collected over time. Significant differences in nutrient concentrations were found in the different sampling seasons and among sampling stations. Multiple regression models developed to estimate the strength of predictive relationships indicated that general land-use categories and seasonality alone were not good predictors of instream nutrient concentrations. Dissolved organic nitrogen and ammonium concentrations were higher in the forested streams, while nitrate and total phosphorus concentrations were higher in the urban streams.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
Estimate the prevalence of medically unnecessary Emergency Medical Services (EMS) transports among children.
We linked EMS and emergency department (ED) billing records for all EMS-to-hospital ...transports of children originating in three counties in South Carolina between January 1, 2001 and March 31, 2003. EMS responses resulting in no transport, transports to destinations other than the ED, or multiple trips for the same child in a single day could not be linked to ED data and were excluded. Medically unnecessary transports were identified with an algorithm using pre-hospital impressions, ED diagnoses and ED procedures. After exclusions, 5,693 transports of children between 0 and 17 years were available for study.
Sixteen percent (16.4%) of all transports were medically unnecessary. Among children through age 12, upper respiratory and viral problems were the most common diagnoses associated with medically unnecessary transports; among older children, behavioral problems such as conduct disturbance or drug abuse were common. In multivariable analysis, the odds of an unnecessary transport were higher among younger children, non-white children, rural children, and children insured by Medicaid.
The proportion of EMS transports which may be medically unnecessary is relatively modest compared to previous studies. However, many questions remain for future research. Further investigation should include examination of primary care availability and occurrence of unnecessary EMS use, existence of race-based disparities, and transports involving conduct disturbance and other behavioral conditions among children.
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DOBA, EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, IZUM, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UILJ, UKNU, UL, UM, UPUK, VKSCE, VSZLJ, ZAGLJ
29.
Modeling Heaped Count Data Cummings, Tammy H.; Hardin, James W.; McLain, Alexander C. ...
The Stata journal,
06/2015, Volume:
15, Issue:
2
Journal Article
Peer reviewed
Open access
We present motivation and new commands for modeling heaped count data. These data may appear when subjects report counts that are rounded or favor multiples (digit preference) of a certain outcome, ...such as the number of cigarettes reported. The new commands for fitting count regression models (Poisson, generalized Poisson, negative binomial) are also accompanied by real-world examples comparing the heaped regression model with the usual regression model as well as the heaped zero-inflated model with the usual zero-inflated model.
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DOBA, IZUM, KILJ, NUK, OILJ, PILJ, PNG, SAZU, UILJ, UKNU, UL, UM, UPUK
We propose a score test for testing independence of the marginals based on Lakshminarayana's bivariate Poisson probability mass function. Each marginal distribution of the bivariate model is a ...univariate Poisson distribution, and the parameters of the bivariate distribution can be estimated using maximum likelihood methods. The simulation study shows that the score test maintains size close to the nominal level. To assess the efficiency of the derived score test, the estimated significance levels and powers of the likelihood ratio and Wald tests as well as Spearman's rank correlation test are calculated and compared. A relevant dataset is used to illustrate the application of the bivariate Poisson model and the proposed score test for independence.
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