Last data update: Jun 03, 2024. (Total: 46935 publications since 2009)
Records 1-12 (of 12 Records) |
Query Trace: LaPlace L [original query] |
---|
The potential distribution of Bacillus anthracis suitability across Uganda using INLA.
Ndolo VA , Redding D , Deka MA , Salzer JS , Vieira AR , Onyuth H , Ocaido M , Tweyongyere R , Azuba R , Monje F , Ario AR , Kabwama S , Kisaakye E , Bulage L , Kwesiga B , Ntono V , Harris J , Wood JLN , Conlan AJK . Sci Rep 2022 12 (1) 19967 To reduce the veterinary, public health, environmental, and economic burden associated with anthrax outbreaks, it is vital to identify the spatial distribution of areas suitable for Bacillus anthracis, the causative agent of the disease. Bayesian approaches have previously been applied to estimate uncertainty around detected areas of B. anthracis suitability. However, conventional simulation-based techniques are often computationally demanding. To solve this computational problem, we use Integrated Nested Laplace Approximation (INLA) which can adjust for spatially structured random effects, to predict the suitability of B. anthracis across Uganda. We apply a Generalized Additive Model (GAM) within the INLA Bayesian framework to quantify the relationships between B. anthracis occurrence and the environment. We consolidate a national database of wildlife, livestock, and human anthrax case records across Uganda built across multiple sectors bridging human and animal partners using a One Health approach. The INLA framework successfully identified known areas of species suitability in Uganda, as well as suggested unknown hotspots across Northern, Eastern, and Central Uganda, which have not been previously identified by other niche models. The major risk factors for B. anthracis suitability were proximity to water bodies (0-0.3 km), increasing soil calcium (between 10 and 25 cmolc/kg), and elevation of 140-190 m. The sensitivity of the final model against the withheld evaluation dataset was 90% (181 out of 202 = 89.6%; rounded up to 90%). The prediction maps generated using this model can guide future anthrax prevention and surveillance plans by the relevant stakeholders in Uganda. |
Spatial-temporal trend for mother-to-child transmission of HIV up to infancy and during pre-Option B+ in western Kenya, 2007-13
Waruru A , Achia TNO , Muttai H , Ng'ang'a L , Zielinski-Gutierrez E , Ochanda B , Katana A , Young PW , Tobias JL , Juma P , De Cock KM , Tylleskär T . PeerJ 2018 2018 (3) e4427 Introduction: Using spatial-temporal analyses to understand coverage and trends in elimination of mother-to-child transmission of HIV (e-MTCT) efforts may be helpful in ensuring timely services are delivered to the right place. We present spatial-temporal analysis of seven years of HIV early infant diagnosis (EID) data collected from 12 districts in western Kenya from January 2007 to November 2013, during pre-Option B+ use. Methods: We included in the analysis infants up to one year old. We performed trend analysis using extended Cochran-Mantel-Haenszel stratified test and logistic regression models to examine trends and associations of infant HIV status at first diagnosis with: early diagnosis ( < 8 weeks after birth), age at specimen collection, infant ever having breastfed, use of single dose nevirapine, and maternal antiretroviral therapy status. We examined these covariates and fitted spatial and spatial-temporal semiparametric Poisson regression models to explain HIVinfection rates using R-integrated nested Laplace approximation package. We calculated new infections per 100,000 live births and used Quantum GIS to map fitted MTCT estimates for each district in Nyanza region. Results: Median age was two months, interquartile range 1.5-5.8 months. Unadjusted pooled positive rate was 11.8% in the seven-years period and declined from 19.7% in 2007 to 7.0% in 2013, p < 0.01. Uptake of testing ≤ 8 weeks after birth was under 50% in 2007 and increased to 64.1% by 2013, p < 0.01. By 2013, the overall standardized MTCTrate was 447 infections per 100,000 live births. Based on Bayesian deviance information criterion comparisons, the spatial-temporal model with maternal and infant covariates was best in explaining geographical variation in MTCT. Discussion: Improved EID uptake and reduced MTCT rates are indicators of progress towards e-MTCT. Cojoined analysis of time and covariates in a spatial context provides a robust approach for explaining differences in programmatic impact over time. Conclusion: During this pre-Option B+ period, the prevention of mother to child transmission program in this region has not achieved e-MTCT target of ≤ 50 infections per 100,000 live births. Geographical disparities in program achievements may signify gaps in spatial distribution of e-MTCT efforts and could indicate areas needing further resources and interventions. |
A Bayesian spatial and temporal modeling approach to mapping geographic variation in mortality rates for subnational areas with R-INLA
Khana D , Rossen LM , Hedegaard H , Warner M . J Data Sci 2018 16 (1) 147-182 Hierarchical Bayes models have been used in disease mapping to examine small scale geographic variation. State level geographic variation for less common causes of mortality outcomes have been reported however county level variation is rarely examined. Due to concerns about statistical reliability and confidentiality, county-level mortality rates based on fewer than 20 deaths are suppressed based on Division of Vital Statistics, National Center for Health Statistics (NCHS) statistical reliability criteria, precluding an examination of spatio-temporal variation in less common causes of mortality outcomes such as suicide rates (SRs) at the county level using direct estimates. Existing Bayesian spatio-temporal modeling strategies can be applied via Integrated Nested Laplace Approximation (INLA) in R to a large number of rare causes of mortality outcomes to enable examination of spatio-temporal variations on smaller geographic scales such as counties. This method allows examination of spatiotemporal variation across the entire U.S., even where the data are sparse. We used mortality data from 2005-2015 to explore spatiotemporal variation in SRs, as one particular application of the Bayesian spatio-temporal modeling strategy in R-INLA to predict year and county-specific SRs. Specifically, hierarchical Bayesian spatio-temporal models were implemented with spatially structured and unstructured random effects, correlated time effects, time varying confounders and space-time interaction terms in the software R-INLA, borrowing strength across both counties and years to produce smoothed county level SRs. Model-based estimates of SRs were mapped to explore geographic variation. |
Measuring antibiotic appropriateness for urinary tract infections in nursing home residents
Eure T , LaPlace LL , Melchreit R , Maloney M , Lynfield R , Whitten T , Warnke L , Dumyati G , Quinlan G , Concannon C , Thompson D , Stone ND , Thompson ND . Infect Control Hosp Epidemiol 2017 38 (8) 1-4 We assessed the appropriateness of initiating antibiotics in 49 nursing home (NH) residents receiving antibiotics for urinary tract infection (UTI) using 3 published algorithms. Overall, 16 residents (32%) received prophylaxis, and among the 33 receiving treatment, the percentage of appropriate use ranged from 15% to 45%. Opportunities exist for improving UTI antibiotic prescribing in NH. Infect Control Hosp Epidemiol 2017;1-4. |
Developing a motion comic for HIV/STD prevention for young people ages 15-24, part 1: Listening to your target audience
Willis LA , Kachur R , Castellanos TJ , Spikes P , Gaul ZJ , Gamayo AC , Durham M , Jones S , Nichols K , Han Barthelemy S , LaPlace L , Staatz C , Hogben M , Robinson S , Brooks JT , Sutton MY . Health Commun 2016 33 (2) 1-10 Young people (15-24 years) in the United States are disproportionately affected by infection with human immunodeficiency virus (HIV) and sexually transmitted diseases (STD). Shortfalls in HIV/STD-related knowledge, attitudes, beliefs, and behavioral intentions (KABI) likely contribute to this discrepancy. In this report we describe our experience developing a novel means of health communication combining entertainment-education theory and recent technological advances to create a HIV/STD-focused "motion comic." We also report the audience satisfaction and acceptance of the intervention. We used the Health Belief Model (HBM), entertainment-education (EE) principles, and the Sabido Method (SM) and conducted three rounds of focus groups to develop a 38-minute HIV/STD focused motion comic for young people between the ages 15 and 24 years. Participants indicated that motion comics were an acceptable method of delivering HIV/STD prevention messages. They also expressed satisfaction with motion comics plot, story settings, the tone of humor, and drama. Our results suggest that motion comics are a viable new method of delivering health communication messages about HIV/STD and other public health issues, and warrant further development and broader evaluation. |
Developing a motion comic for HIV/STD prevention for young people ages 15-24, part 2: Evaluation of a pilot intervention
Willis LA , Kachur R , Castellanos TJ , Nichols K , Mendoza MC , Gaul ZJ , Spikes P , Gamayo AC , Durham MD , LaPlace L , Straw J , Staatz C , Buge H , Hogben M , Robinson S , Brooks J , Sutton MY . Health Commun 2016 33 (3) 1-9 In the United States, young people (ages 15-24 years) are disproportionately affected by human immunodeficiency virus (HIV) and other sexually transmitted diseases (STDs), due at least in part to inadequate or incorrect HIV/STD-related knowledge, attitudes, beliefs, and behavioral intentions (KABI). Comic book narratives are a proven method of HIV/STD prevention communication to strengthen KABI for HIV/STD prevention. Motion comics, a new type of comic media, are an engaging and low-cost means of narrative storytelling. The objective of this study was to quantitatively evaluate the effectiveness of a pilot six-episode HIV/STD-focused motion comic series to improve HIV/STD-related KABI among young people. We assessed change in HIV/STD knowledge, HIV stigma, condom attitudes, HIV/STD testing attitudes, and behavioral intentions among 138 participants in 15 focus groups immediately before and after viewing the motion comic series. We used paired t-tests and indicators of overall improvement to assess differences between surveys. We found a significant decrease in HIV stigma (p < .001) and increases in both HIV knowledge (p = .002) and behavioral intentions to engage in safe sex (p < .001). In summary, this motion comic intervention improved HIV/STD-related KABI of young adult viewers by reducing HIV stigma and increasing behavioral intentions to engage in safer sex. Our results demonstrate the promise of this novel intervention and support its use to deliver health messages to young people. |
Prevalence of antimicrobial use and opportunities to improve prescribing practices in U.S. nursing homes
Thompson ND , LaPlace L , Epstein L , Thompson D , Dumyati G , Concannon C , Quinlan G , Witten T , Warnke L , Lynfield R , Maloney M , Melchreit R , Stone ND . J Am Med Dir Assoc 2016 17 (12) 1151-1153 OBJECTIVES: To describe the prevalence and epidemiology of antimicrobial use (AU) in nursing home residents. DESIGN: One-day point prevalence survey. SETTING AND PARTICIPANTS: Nine nursing homes in four states; 1,272 eligible residents. MEASUREMENT: Frequency of antimicrobials prescribed, drug name, start date, duration, route, rationale, and treatment site. AU prevalence per 100 residents overall and by resident characteristic. RESULTS: AU prevalence was 11.1% (95% confidence interval, 9.4%-12.9%) and varied by resident characteristics. Most (32%) antimicrobials were given for urinary tract infection. For 38% of AU, key prescribing information was not documented. CONCLUSION: Opportunities to improve AU documentation and prescribing exist in nursing homes. |
Comparison of data collection for healthcare-associated infection surveillance in nursing homes
Epstein L , Stone ND , LaPlace L , Harper J , Lynfield R , Warnke L , Whitten T , Maloney M , Melchreit R , Rodriguez R , Quinlan G , Concannon C , Dumyati G , Thompson DL , Thompson N . Infect Control Hosp Epidemiol 2016 37 (12) 1-6 OBJECTIVE To facilitate surveillance and describe the burden of healthcare-associated infection (HAI) in nursing homes (NHs), we compared the quality of resident-level data collected by NH personnel and external staff. DESIGN A 1-day point-prevalence survey SETTING AND PARTICIPANTS Overall, 9 nursing homes among 4 Centers for Disease Control and Prevention (CDC) Emerging Infection Program (EIP) sites were included in this study. METHODS NH personnel collected data on resident characteristics, clinical risk factors for HAIs, and the presence of 3 HAI screening criteria on the day of the survey. Trained EIP surveillance officers collected the same data elements via retrospective medical chart review for comparison; surveillance officers also collected available data to identify HAIs (using revised McGeer definitions). Overall agreement was calculated among residents identified by both teams with selected risk factors and HAI screening criteria. The impact of using NH personnel to collect screening criteria on HAI prevalence was assessed. RESULTS The overall prevalence of clinical risk factors among the 1,272 residents was similar between NH personnel and surveillance officers, but the level of positive agreement (residents with factors identified by both teams) varied between 39% and 87%. Surveillance officers identified 253 residents (20%) with ≥1 HAI screening criterion, resulting in 67 residents with an HAI (5.3 per 100 residents). The NH personnel identified 152 (12%) residents with ≥1 HAI screening criterion; 42 residents had an HAI (3.5 per 100 residents). CONCLUSION We identified discrepancies in resident-level data collection between surveillance officers and NH personnel, resulting in varied estimates of the HAI prevalence. These findings have important implications for the design and implementation of future HAI prevalence surveys. Infect Control Hosp Epidemiol 2016;1-6. |
Approximation of the ruin probability using the scaled Laplace transform inversion
Mnatsakanov RM , Sarkisian K , Hakobyan A . Appl Math Comput 2015 268 717-727 The problem of recovering the ruin probability in the classical risk model based on the scaled Laplace transform inversion is studied. It is shown how to overcome the problem of evaluating the ruin probability at large values of an initial surplus process. Comparisons of proposed approximations with the ones based on the Laplace transform inversions using a fixed Talbot algorithm as well as on the ones using the Trefethen–Weideman–Schmelzer and maximum entropy methods are presented via a simulation study. |
The transient dermal exposure II: post-exposure absorption and evaporation of volatile compounds
Frasch HF , Bunge AL . J Pharm Sci 2015 104 (4) 1499-507 The transient dermal exposure is one where the skin is exposed to chemical for a finite duration, after which the chemical is removed and no residue remains on the skin's surface. Chemical within the skin at the end of the exposure period can still enter the systemic circulation. If it has some volatility, a portion of it will evaporate from the surface before it has a chance to be absorbed by the body. The fate of this post-exposure "skin depot" is the focus of this theoretical study. Laplace domain solutions for concentration distribution, flux, and cumulative mass absorption and evaporation are presented, and time domain results are obtained through numerical inversion. The Final Value Theorem is applied to obtain the analytical solutions for the total fractional absorption by the body and evaporation from skin at infinite time following a transient exposure. The solutions depend on two dimensionless variables: chi, the ratio of evaporation rate to steady-state dermal permeation rate; and the ratio of exposure time to membrane lag time. Simple closed form algebraic equations are presented that closely approximate the complete analytical solutions. Applications of the theory to the dermal risk assessment of pharmaceutical, occupational, and environmental exposures are presented for four example chemicals. |
A note on recovering the distributions from exponential moments
Mnatsakanov RM , Sarkisian K . Appl Math Comput 2013 219 (16) 8730-8737 The problem of recovering a cumulative distribution function of a positive random variable via the scaled Laplace transform inversion is studied. The uniform upper bound of proposed approximation is derived. The approximation of a compound Poisson distribution as well as the estimation of a distribution function of the summands given the sample from a compound Poisson distribution are investigated. Applying the simulation study, the question of selecting the optimal scaling parameter of the proposed Laplace transform inversion is considered. The behavior of the approximants are demonstrated via plots and table. |
Dermal absorption of finite doses of volatile compounds
Frasch HF . J Pharm Sci 2012 101 (7) 2616-9 Laplace domain solutions to a previously published finite dose skin diffusion model are presented. The purpose of the current analysis is to derive a simple algebraic expression quantifying the total mass that is systemically absorbed at infinite time after exposure, relative to the applied mass. The resulting expression is a function of two dimensionless parameters: f, the fractional depth within the skin surface through which the permeant is initially deposited, and chi, the ratio of maximum evaporation flux to maximum dermal flux. The result may be useful for dermal risk assessment as well as in the evaluation of cosmetic and pharmaceutical product performance. ((c) 2012 Wiley Periodicals, Inc. and the American Pharmacists Association J Pharm Sci.) |
- Page last reviewed:Feb 1, 2024
- Page last updated:Jun 03, 2024
- Content source:
- Powered by CDC PHGKB Infrastructure