Pessimistic orientation in relation to telomere length in older men: the VA Normative Aging Study

PubMed Central

Ikeda, Ai; Schwartz, Joel; Peters, Junenette L.; Baccarelli, Andrea A.; Hoxha, Mirjam; Dioni, Laura; Spiro, Avron; Sparrow, David; Vokonas, Pantel; Kubzansky, Laura D.

2014-01-01

Background Recent research suggests pessimistic orientation is associated with shorter leukocyte telomere length (LTL). However, this is the first study to look not only at effects of pessimistic orientation on average LTL at multiple time points, but also at effects on the rate of change in LTL over time. Methods Participants were older men from the VA Normative Aging Study (n=490). The Life Orientation Test (LOT) was used to measure optimistic and pessimistic orientations at study baseline, and relative LTL by telomere to single copy gene ratio (T:S ratio) was obtained repeatedly over the course of the study (1999-2008). A total of 1,010 observations were included in the analysis. Linear mixed effect models with a random subject intercept were used to estimate associations. Results Higher pessimistic orientation scores were associated with shorter average LTL (percent difference by 1-SD increase in pessimistic orientation (95% CI): -3.08 (-5.62, -0.46)), and the finding was maintained after adjusting for the higher likelihood that healthier individuals return for follow-up visits (-3.44 (-5.95,-0.86)). However, pessimistic orientation scores were not associated with rate of change in LTL over time. No associations were found between overall optimism and optimistic orientation subscale scores and LTL. Conclusion Higher pessimistic orientation scores were associated with shorter LTL in older men. While there was no evidence that pessimistic orientation was associated with rate of change in LTL over time, higher levels of pessimistic orientation were associated with shorter LTL at baseline and this association persisted over time. PMID:24636503

Sports and Exercise at Different Ages and Leukocyte Telomere Length in Later Life--Data from the Berlin Aging Study II (BASE-II).

PubMed

Saßenroth, Denise; Meyer, Antje; Salewsky, Bastian; Kroh, Martin; Norman, Kristina; Steinhagen-Thiessen, Elisabeth; Demuth, Ilja

2015-01-01

Physical activity and sports have repeatedly been reported to be associated with telomere length. We studied the association of different types of sports across different stages of life on relative leukocyte telomere length (rLTL) in advanced age.815 participants (397 men) from the Berlin Aging Study II aged over 61 years were included in the analysis. rLTL was measured by real time PCR and physical activity was determined retrospectively by questionnaire, assessing type and duration of sports in the past as well as currently. Five separate multiple linear regression models adjusted for various control variables were performed. 67.3% of participants exercised currently, whereas 19.4% performed sports only between the age of 20 and 30. rLTL was higher in subjects who stated to exercise currently (N = 456), and in subjects who engaged in endurance (N = 138) or intensive activity sports (N = 32). Current physical activity was positively associated with rLTL in the risk factor adjusted regression model (β = 0.26, p < 0.001) and practicing sports for a minimum of 10 years preceding the assessment had a significant effect on rLTL (β = 0.39, p = 0.011). The highest impact was seen for intensive activity sports (β = 0.79, p < 0.001) and physical activity since at least 42 years (β = 0.47, p = 0.001). However, physical activity only between 20 and 30 years of age did not affect rLTL in old age when compared to no sports at all (β = -0.16, p = 0.21). Physical activity is clearly associated with longer rLTL. The effect is seen with longer periods of physical activity (at least 10 years), with intensive sports activities having the greatest impact on rLTL. Our data suggest that regular physical activity for at least 10 years is necessary to achieve a sustained effect on rLTL.

Aberrant leukocyte telomere length in Birdshot Uveitis.

PubMed

Vazirpanah, Nadia; Verhagen, Fleurieke H; Rothova, Anna; Missotten, Tom O A R; van Velthoven, Mirjam; Den Hollander, Anneke I; Hoyng, Carel B; Radstake, Timothy R D J; Broen, Jasper C A; Kuiper, Jonas J W

2017-01-01

Birdshot Uveitis (BU) is an archetypical chronic inflammatory eye disease, with poor visual prognosis, that provides an excellent model for studying chronic inflammation. BU typically affects patients in the fifth decade of life. This suggests that it may represent an age-related chronic inflammatory disease, which has been linked to increased erosion of telomere length of leukocytes. To study this in detail, we exploited a sensitive standardized quantitative real-time polymerase chain reaction to determine the peripheral blood leukocyte telomere length (LTL) in 91 genotyped Dutch BU patients and 150 unaffected Dutch controls. Although LTL erosion rates were very similar between BU patients and healthy controls, we observed that BU patients displayed longer LTL, with a median of log (LTL) = 4.87 (= 74131 base pair) compared to 4.31 (= 20417 base pair) in unaffected controls (P<0.0001). The cause underpinning the difference in LTL could not be explained by clinical parameters, immune cell-subtype distribution, nor genetic predisposition based upon the computed weighted genetic risk score of genotyped validated variants in TERC, TERT, NAF1, OBFC1 and RTEL1. These findings suggest that BU is accompanied by significantly longer LTL.

Larger than Life's Extremes: Rigorous Results for Simplified Rules and Speculation on the Phase Boundaries

NASA Astrophysics Data System (ADS)

Evans, Kellie Michele

Larger than Life (LtL), is a four-parameter family of two-dimensional cellular automata that generalizes John Conway's Game of Life (Life) to large neighborhoods and general birth and survival thresholds. LtL was proposed by David Griffeath in the early 1990s to explore whether Life might be a clue to a critical phase point in the threshold-range scaling limit. The LtL family of rules includes Life as well as a rich set of two-dimensional rules, some of which exhibit dynamics vastly different from Life. In this chapter we present rigorous results and conjectures about the ergodic classifications of several sets of "simplified" LtL rules, each of which has a property that makes the rule easier to analyze. For example, these include symmetric rules such as the threshold voter automaton and the anti-voter automaton, monotone rules such as the threshold growth models, and others. We also provide qualitative results and speculation about LtL rules on various phase boundaries and summarize results and open questions about our favorite "Life-like" LtL rules.

Genetic determinants of leucocyte telomere length in children: a neglected and challenging field.

PubMed

Stathopoulou, Maria G; Petrelis, Alexandros M; Buxton, Jessica L; Froguel, Philippe; Blakemore, Alexandra I F; Visvikis-Siest, Sophie

2015-03-01

Telomere length is associated with a large range of human diseases. Genome-wide association studies (GWAS) have identified genetic variants that are associated with leucocyte telomere length (LTL). However, these studies are limited to adult populations. Nevertheless, childhood is a crucial period for the determination of LTL, and the assessment of age-specific genetic determinants, although neglected, could be of great importance. Our aim was to provide insights and preliminary results on genetic determinants of LTL in children. Healthy children (n = 322, age range = 6.75-17 years) with available GWAS data (Illumina Human CNV370-Duo array) were included. The LTL was measured using multiplex quantitative real-time polymerase chain reaction. Linear regression models adjusted for age, gender, parental age at child's birth, and body mass index were used to test the associations of LTL with polymorphisms identified in adult GWAS and to perform a discovery-only GWAS. The previously GWAS-identified variants in adults were not associated with LTL in our paediatric sample. This lack of association was not due to possible interactions with age or gene × gene interactions. Furthermore, a discovery-only GWAS approach demonstrated six novel variants that reached the level of suggestive association (P ≤ 5 × 10(-5)) and explain a high percentage of children's LTL. The study of genetic determinants of LTL in children may identify novel variants not previously identified in adults. Studies in large-scale children populations are needed for the confirmation of these results, possibly through a childhood consortium that could better handle the methodological challenges of LTL genetic epidemiology field. © 2015 John Wiley & Sons Ltd.

Baseline Telomere Length and Effects of a Multidomain Lifestyle Intervention on Cognition: The FINGER Randomized Controlled Trial

PubMed Central

Sindi, Shireen; Ngandu, Tiia; Hovatta, Iiris; Kåreholt, Ingemar; Antikainen, Riitta; Hänninen, Tuomo; Levälahti, Esko; Laatikainen, Tiina; Lindström, Jaana; Paajanen, Teemu; Peltonen, Markku; Khalsa, Dharma Singh; Wolozin, Benjamin; Strandberg, Timo; Tuomilehto, Jaakko; Soininen, Hilkka; Kivipelto, Miia; Solomon, Alina

2017-01-01

Leukocyte telomere length (LTL) is a biomarker of aging, and it is associated with lifestyle. It is currently unknown whether LTL is associated with the response to lifestyle interventions. The goal is to assess whether baseline LTL modified the cognitive benefits of a 2-year multidomain lifestyle intervention (exploratory analyses). The Finnish Geriatric Intervention Study to Prevent Cognitive Impairment and Disability (FINGER) was a 2-year randomized controlled trial including 1,260 people at risk of cognitive decline, aged 60–77 years identified from the general population. Participants were randomly assigned to the lifestyle intervention (diet, exercise, cognitive training, and vascular risk management) and control (general health advice) groups. Primary outcome was change in cognition (comprehensive neuropsychological test battery). Secondary outcomes were changes in cognitive domains: memory, executive functioning, and processing speed. 775 participants (392 control, 383 intervention) had baseline LTL (peripheral blood DNA). Mixed effects regression models with maximum likelihood estimation were used to analyze change in cognition as a function of randomization group, time, baseline LTL, and their interaction. Intervention and control groups did not significantly differ at baseline. Shorter LTL was related to less healthy baseline lifestyle. Intervention benefits on executive functioning were more pronounced among those with shorter baseline LTL (p-value for interaction was 0.010 adjusted for age and sex, and 0.007 additionally adjusted for baseline lifestyle factors). The FINGER intervention cognitive benefits were more pronounced with shorter baseline LTL, particularly for executive functioning, indicating that the multidomain lifestyle intervention was especially beneficial among higher-risk individuals. PMID:28777749

Baseline Telomere Length and Effects of a Multidomain Lifestyle Intervention on Cognition: The FINGER Randomized Controlled Trial.

PubMed

Sindi, Shireen; Ngandu, Tiia; Hovatta, Iiris; Kåreholt, Ingemar; Antikainen, Riitta; Hänninen, Tuomo; Levälahti, Esko; Laatikainen, Tiina; Lindström, Jaana; Paajanen, Teemu; Peltonen, Markku; Khalsa, Dharma Singh; Wolozin, Benjamin; Strandberg, Timo; Tuomilehto, Jaakko; Soininen, Hilkka; Kivipelto, Miia; Solomon, Alina

2017-01-01

Leukocyte telomere length (LTL) is a biomarker of aging, and it is associated with lifestyle. It is currently unknown whether LTL is associated with the response to lifestyle interventions. The goal is to assess whether baseline LTL modified the cognitive benefits of a 2-year multidomain lifestyle intervention (exploratory analyses). The Finnish Geriatric Intervention Study to Prevent Cognitive Impairment and Disability (FINGER) was a 2-year randomized controlled trial including 1,260 people at risk of cognitive decline, aged 60-77 years identified from the general population. Participants were randomly assigned to the lifestyle intervention (diet, exercise, cognitive training, and vascular risk management) and control (general health advice) groups. Primary outcome was change in cognition (comprehensive neuropsychological test battery). Secondary outcomes were changes in cognitive domains: memory, executive functioning, and processing speed. 775 participants (392 control, 383 intervention) had baseline LTL (peripheral blood DNA). Mixed effects regression models with maximum likelihood estimation were used to analyze change in cognition as a function of randomization group, time, baseline LTL, and their interaction. Intervention and control groups did not significantly differ at baseline. Shorter LTL was related to less healthy baseline lifestyle. Intervention benefits on executive functioning were more pronounced among those with shorter baseline LTL (p-value for interaction was 0.010 adjusted for age and sex, and 0.007 additionally adjusted for baseline lifestyle factors). The FINGER intervention cognitive benefits were more pronounced with shorter baseline LTL, particularly for executive functioning, indicating that the multidomain lifestyle intervention was especially beneficial among higher-risk individuals.

Short leukocyte telomere length is associated with obesity in American Indians: the Strong Heart Family study.

PubMed

Chen, Shufeng; Yeh, Fawn; Lin, Jue; Matsuguchi, Tet; Blackburn, Elizabeth; Lee, Elisa T; Howard, Barbara V; Zhao, Jinying

2014-05-01

Shorter leukocyte telomere length (LTL) has been associated with a wide range of age-related disorders including cardiovascular disease (CVD) and diabetes. Obesity is an important risk factor for CVD and diabetes. The association of LTL with obesity is not well understood. This study for the first time examines the association of LTL with obesity indices including body mass index, waist circumference, percent body fat, waist-to-hip ratio, and waist-to-height ratio in 3,256 American Indians (14-93 years old, 60% women) participating in the Strong Heart Family Study. Association of LTL with each adiposity index was examined using multivariate generalized linear mixed model, adjusting for chronological age, sex, study center, education, lifestyle (smoking, alcohol consumption, and total energy intake), high-sensitivity C-reactive protein, hypertension and diabetes. Results show that obese participants had significantly shorter LTL than non-obese individuals (age-adjusted P=0.0002). Multivariate analyses demonstrate that LTL was significantly and inversely associated with all of the studied obesity parameters. Our results may shed light on the potential role of biological aging in pathogenesis of obesity and its comorbidities.

Deconvolution of the PSF of a seismic lens

NASA Astrophysics Data System (ADS)

Yu, Jianhua; Wang, Yue; Schuster, Gerard T.

2002-12-01

We show that if seismic data d is related to the migration image by mmig = LTd. then mmig is a blurred version of the actual reflectivity distribution m, i.e., mmig = (LTL)m. Here L is the acoustic forward modeling operator under the Born approximation where d = Lm. The blurring operator (LTL), or point spread function, distorts the image because of defects in the seismic lens, i.e., small source-receiver recording aperture and irregular/coarse geophone-source spacing. These distortions can be partly suppressed by applying the deblurring operator (LTL)-1 to the migration image to get m = (LTL)-1mmig. This deblurred image is known as a least squares migration (LSM) image if (LTL)-1LT is applied to the data d using a conjugate gradient method, and is known as a migration deconvolved (MD) image if (LTL)-1 is directly applied to the migration image mmig in (kx, ky, z) space. The MD algorithm is an order-of-magnitude faster than LSM, but it employs more restrictive assumptions. We also show that deblurring can be used to filter out coherent noise in the data such as multiple reflections. The procedure is to, e.g., decompose the forward modeling operator into both primary and multiple reflection operators d = (Lprim + Lmulti)m, invert for m, and find the primary reflection data by dprim = Lprimm. This method is named least squares migration filtering (LSMF). The above three algorithms (LSM, MD and LSMF) might be useful for attacking problems in optical imaging.

Telomere Length and the Risk of Atrial Fibrillation: Insights into the Role of Biological versus Chronological Aging

PubMed Central

Roberts, Jason D.; Dewland, Thomas A.; Longoria, James; Fitzpatrick, Annette L.; Ziv, Elad; Hu, Donglei; Lin, Jue; Glidden, David V.; Psaty, Bruce M.; Burchard, Esteban G.; Blackburn, Elizabeth H.; Olgin, Jeffrey E.; Heckbert, Susan R.; Marcus, Gregory M.

2014-01-01

Background Advanced age is the most important risk factor for atrial fibrillation (AF), however the mechanism remains unknown. Telomeres, regions of DNA that shorten with cell division, are considered reliable markers of biological aging. We sought to examine the association between leukocyte telomere length (LTL) and incident AF in a large population-based cohort using direct LTL measurements and genetic data. To further explore our findings, we compared atrial cell telomere length (ATL) and LTL in cardiac surgery patients. Methods and Results Mean LTL and the TERT rs2736100 single nucleotide polymorphism (SNP) were assessed as predictors of incident AF in the Cardiovascular Health Study (CHS). Among the surgical patients, within subject comparison of ATL versus LTL was assessed. Among 1639 CHS participants, we observed no relationship between mean LTL and incident AF prior to and after adjustment for potential confounders (adjusted hazard ratio [HR] 1.09; 95% CI: 0.92–1.29, p=0.299); chronologic age remained strongly associated with AF in the same model. No association was observed between the TERT rs2736100 SNP and incident AF (adjusted HR: 0.95; 95% CI: 0.88–1.04, p=0.265). In 35 cardiac surgery patients (26 with AF), ATL was longer than LTL (1.19 ± 0.20 versus 1.02 ± 0.25 [T/S ratio], p< 0.001), a finding that remained consistent within the AF subgroup. Conclusions Our study revealed no evidence of an association between LTL and incident AF and no evidence of relative atrial cell telomere shortening in AF. Chronological aging independent of biological markers of aging is the primary risk factor for AF. PMID:25381796

Polymorphisms in Telomere Length Associated TERC and TERT predispose for Ischemic Stroke in a Chinese Han population.

PubMed

Zhang, Shuo; Ji, Guofa; Liang, Yiqian; Zhang, Rui; Shi, Puyu; Guo, Dangshe; Li, Chunqi; Feng, Jing; Liu, Feng; Peng, Rong; Chen, Mingwei

2017-01-06

The role of telomere in genomic stability is an established fact. Variation in leukocyte telomere length (LTL) has been considered a crucial factor that associated with age-associated diseases. To elucidate the association between LTL variation and ischemic stroke (IS) risk, we selected ten single nucleotide polymorphisms (SNPs) in three genes (TERC, TERT and RTEL1) that previously reported link to LTL, and genotyped SNPs of these genes in a case-control study. The association between polymorphisms and IS risk were tested by Chi squared test and haplotype analysis. In allele association analysis, allele "C" in rs10936599 of TERC gene and allele "G" in rs2853677 of TERT gene were found to have an increased risk of IS when compared with allele "T" and "A", respectively. Model association analysis showed that genotype "G/A" in the overdominant model and genotypes "G/A" and "A/A" in the dominant model of rs2242652 presented a more likelihood to have IS. Another TERT locus (rs2853677) with genotype "G" was also found IS-related risky in the log-additive model. Taken together, our results suggest a potential association between LTL related TERC, TERT gene variants and ischemic stroke risk.

Sociodemographic correlates and family aggregation of leukocyte telomere length in adults and children from Mesoamerica.

PubMed

Flannagan, Kerry S; Jansen, Erica C; Rozek, Laura S; Rentschler, Katie M; Roman, Ana Victoria; Ramirez-Zea, Manuel; Villamor, Eduardo

2017-05-06

Telomere length is a biomarker of cumulative stress and inflammation related to chronic disease risk. We examined the associations of leukocyte telomere length (LTL) with sociodemographic and anthropometric variables and estimated LTL family aggregation in Central America, a region with a high burden of chronic disease where LTL has not been studied. We conducted a cross-sectional study of 174 school age children and their parents in the capital cities of Belize, Honduras, Nicaragua, Costa Rica, Panama, and the city of Tuxtla-Gutierrez in Mexico. We measured LTL by quantitative PCR in DNA extracted from whole blood. We compared the distribution of LTL by categories of sociodemographic and anthropometric characteristics using linear regression. Family aggregation was estimated with correlation coefficients and intraclass correlations. In mothers, LTL was inversely associated with age (P, trend < .0001) and positively associated with height (P = .0002). Among fathers, LTL was inversely associated with food insecurity (P, trend = .0004). In children, boys had 0.10 log units shorter LTL than girls (95% CI: -0.17, -0.03; P = .004). LTL was inversely associated with parental education (P, trend = .01) and positively associated with paternal age at birth (P, trend < .0001), maternal LTL (P, trend = .007), and paternal LTL (P, trend = .02). LTL varied significantly by country of origin among all family members. Aggregation was greatest between children and their mothers, and mostly occurred at the country, rather than family, level. LTL is associated with age and height in women; food insecurity in men; and sex, parental education, parental LTL, and paternal age at birth among children. © 2016 Wiley Periodicals, Inc.

Accelerated leukocyte telomere erosion in schizophrenia: Evidence from the present study and a meta-analysis.

PubMed

Rao, Shuquan; Kota, Lakshmi Narayanan; Li, Zongchang; Yao, Yao; Tang, Jinsong; Mao, Canquan; Jain, Sanjeev; Xu, Yong; Xu, Qi

2016-08-01

Human telomeres consist of tandem nucleotide repeats (TTAGGG) and associated proteins, and telomere length (TL) is reduced progressively with cell division over the lifespan. Telomere erosion might be accelerated or prevented to varying degrees when exposure to serious medical illnesses. In previous studies, an association between TL decrease and schizophrenia has been extensively reported; however, the results remain largely controversial. To further investigate TL in schizophrenia patients and reconcile this controversy, we first measured leucocyte TL (LTL) in our samples (52 paranoid schizophrenia, 89 non-paranoid patients and 120 controls), and then conducted a comprehensive meta-analysis of the existing results of LTL in patients of schizophrenia compared to healthy subjects. Totally, 11 studies encompassing 1243 patients of schizophrenia and 1274 controls were included in the final meta-analysis model. In our samples, significant reduction of LTL in paranoid schizophrenia was observed compared to controls (F = 50.88, P < 0.001); whereas there was no significant difference in LTL between non-paranoid schizophrenia and controls (F = 0.842, P = 0.360). For meta-analysis, random-effects model showed significant LTL decrease in patients of schizophrenia when compared to controls (Z = 2.07, P = 0.039, SMD = -0.48, 95% CI = -0.94 to -0.03). Moreover, a marginal decrease in LTL was observed in medicated patients (Z = 1.92, P = 0.055, SMD = -0.58, 95% CI = -1.18-0.01) and those patients with poor response to antipsychotics (Z = 1.76, P = 0.078, SMD = -0.60, 95% CI = -1.27-0.07). In conclusion, we observed significant reduction of LTL in individuals with schizophrenia compared with controls. However, all the studies included in the meta-analysis were cross-sectional, and better controlled long-term studies are needed to replicate this result. Copyright © 2016 Elsevier Ltd. All rights reserved.

Association between leukocyte telomere length and bone mineral density in women 25-93 years of age.

PubMed

Nielsen, Barbara Rubek; Linneberg, Allan; Bendix, Laila; Harboe, Maria; Christensen, Kaare; Schwarz, Peter

2015-06-01

Leukocyte telomere length (LTL) and bone mineral density (BMD) are associated with health and mortality. Because osteoporosis is an age-related condition and LTL is considered to be a biomarker of aging, we hypothesized that shorter LTL could predict lower BMD. The aim of our study was to assess whether there is an association of LTL with BMD and to determine whether this possible association is independent of age. The BMDs of the lumbar spine (LS), femoral neck (FN) and total hip (TH) were evaluated in 460 women using DXA. LTL was analyzed using quantitative polymerase chain reaction. The women completed a health and lifestyle questionnaire. The associations were estimated by regression models that considered age, body mass index (BMI), menopause, physical activity, alcohol consumption and smoking habits. We found a statistically significant unadjusted association between LTL and age (estimate and 95% confidence interval (CI): -0.003 (-0.005; -0.002)); and between BMI adjusted age and logarithmic transformed BMD. Estimates and 95% CI were as follows: LS: -0.13 (-0.26; -0.01); right TH: -0.44 (-0.53; -0.34); left TH: -0.38 (-0.48; -0.28); right FN: -0.57 (-0.67; -0.46) and left FN: -0.51 (-0.62; -0.40). There were no statistically significant associations between BMD and LTL (both logarithmically transformed) with or without age adjustments. The age-adjusted estimates and CI were as follows: LS: -0.10 (-0.71; 0.52); right TH: -0.13 (-0.66; 0.41); left TH: -0.13 (-0.67; 0.42); right FN: -0.03 (-0.58; 0.52) and left FN: 0.09 (-0.47; 0.66). In conclusion, we found no statistically significant associations between BMD and LTL, although the estimates of the crude associations were all positive, indicating hypothesis consistency; that shorter LTL predict lower BMD values. This positive association was no longer apparent after adjusting for age. As expected, age was statistically significantly associated with both telomere length and BMI adjusted BMD. Copyright © 2015 Elsevier Inc. All rights reserved.

Molecular characterization and expression analysis of Lily-type lectin ( SmLTL) in turbot Scophthalmus maximus, and its response to Vibrio anguillarum

NASA Astrophysics Data System (ADS)

Xia, Dandan; Ma, Aijun; Huang, Zhihui; Shang, Xiaomei; Cui, Wenxiao; Yang, Zhi; Qu, Jiangbo

2018-03-01

A full-length lily-type lectin ( SmLTL) was identified from turbot ( Scophthalmus maximus) in this study. By searching database for protein identification and function prediction, SmLTL were confirmed. The full-length cDNA of SmLTL is composed of 569 bp and contains a 339 bp ORF that encodes 112 amino acid residues. The SmLTL peptide is characterized by a specific β-prism architecture and contains three mannose binding sites in a three-fold internal repeat between amino acids 30-99; two of the repeats share the classical mannose binding domain (QxDxNxVxY) while the third binding site was similar to other fish-specific binding motifs (TxTxGxRxV). The primary, secondary, and tertiary structures of SmLTL were predicted and analyzed, indicating that the SmLTL protein was hydrophilic, contained 5.36% α-helices, 39.29% extended strands, 16.07% β-folds, and 39.29% random coils, and three β-folds. Quantitative realtime polymerase chain reaction (qPCR) analysis revealed that the SmLTL mRNA was abundantly expressed in skin, gill, and intestine. Low levels of SmLTL expression were observed in other tissues. The expression of SmLTL in gill, skin and intestine increased at mRNA level after stimulation of Vibrio anguillarum, our results suggest that SmLTL serve as the first line of defence against microbial infections and play a pivotal role in the innate mucosal immune system. The current study indicates that SmLTL is a member of the lilytype lectin family and the information reported here will provide an important foundation for future research on the role of this protein.

A Test of Biological and Behavioral Explanations for Gender Differences in Telomere Length: The Multi-Ethnic Study of Atherosclerosis

PubMed Central

NEEDHAM, BELINDA L.; DIEZ ROUX, ANA V.; BIRD, CHLOE E.; BRADLEY, RYAN; FITZPATRICK, ANNETTE L.; JACOBS, DAVID R.; OUYANG, PAMELA; SEEMAN, TERESA E.; THURSTON, REBECCA C.; VAIDYA, DHANANJAY; WANG, STEVEN

2015-01-01

The purpose of this study was to examine biological and behavioral explanations for gender differences in leukocyte telomere length (LTL), a biomarker of cell aging that has been hypothesized to contribute to women’s greater longevity. Data are from a subsample (n = 851) of the Multi-Ethnic Study of Atherosclerosis, a population-based study of women and men aged 45 to 84. Mediation models were used to examine study hypotheses. We found that women had longer LTL than men, but the gender difference was smaller at older ages. Gender differences in smoking and processed meat consumption partially mediated gender differences in telomere length, whereas gender differences in estradiol, total testosterone, oxidative stress, and body mass index did not. Neither behavioral nor biological factors explained why the gender difference in LTL was smaller at older ages. Longitudinal studies are needed to assess gender differences in the rate of change in LTL over time; to identify the biological, behavioral, and psychosocial factors that contribute to these differences throughout the life course; and to determine whether gender differences in LTL explain the gender gap in longevity. PMID:25343364

A test of biological and behavioral explanations for gender differences in telomere length: the multi-ethnic study of atherosclerosis.

PubMed

Needham, Belinda L; Diez Roux, Ana V; Bird, Chloe E; Bradley, Ryan; Fitzpatrick, Annette L; Jacobs, David R; Ouyang, Pamela; Seeman, Teresa E; Thurston, Rebecca C; Vaidya, Dhananjay; Wang, Steven

2014-01-01

The purpose of this study was to examine biological and behavioral explanations for gender differences in leukocyte telomere length (LTL), a biomarker of cell aging that has been hypothesized to contribute to women's greater longevity. Data are from a subsample (n = 851) of the Multi-Ethnic Study of Atherosclerosis, a population-based study of women and men aged 45 to 84. Mediation models were used to examine study hypotheses. We found that women had longer LTL than men, but the gender difference was smaller at older ages. Gender differences in smoking and processed meat consumption partially mediated gender differences in telomere length, whereas gender differences in estradiol, total testosterone, oxidative stress, and body mass index did not. Neither behavioral nor biological factors explained why the gender difference in LTL was smaller at older ages. Longitudinal studies are needed to assess gender differences in the rate of change in LTL over time; to identify the biological, behavioral, and psychosocial factors that contribute to these differences throughout the life course; and to determine whether gender differences in LTL explain the gender gap in longevity.

SEAPODYM-LTL: a parsimonious zooplankton dynamic biomass model

NASA Astrophysics Data System (ADS)

Conchon, Anna; Lehodey, Patrick; Gehlen, Marion; Titaud, Olivier; Senina, Inna; Séférian, Roland

2017-04-01

Mesozooplankton organisms are of critical importance for the understanding of early life history of most fish stocks, as well as the nutrient cycles in the ocean. Ongoing climate change and the need for improved approaches to the management of living marine resources has driven recent advances in zooplankton modelling. The classical modeling approach tends to describe the whole biogeochemical and plankton cycle with increasing complexity. We propose here a different and parsimonious zooplankton dynamic biomass model (SEAPODYM-LTL) that is cost efficient and can be advantageously coupled with primary production estimated either from satellite derived ocean color data or biogeochemical models. In addition, the adjoint code of the model is developed allowing a robust optimization approach for estimating the few parameters of the model. In this study, we run the first optimization experiments using a global database of climatological zooplankton biomass data and we make a comparative analysis to assess the importance of resolution and primary production inputs on model fit to observations. We also compare SEAPODYM-LTL outputs to those produced by a more complex biogeochemical model (PISCES) but sharing the same physical forcings.

Growth Hormone, Insulin-Like Growth Factor-1, Insulin Resistance, and Leukocyte Telomere Length as Determinants of Arterial Aging in Subjects Free of Cardiovascular Diseases

PubMed Central

Strazhesko, Irina D.; Tkacheva, Olga N.; Akasheva, Dariga U.; Dudinskaya, Ekaterina N.; Plokhova, Ekaterina V.; Pykhtina, Valentina S.; Kruglikova, Anna S.; Brailova, Natalia V.; Sharashkina, Natalia V.; Kashtanova, Daria A.; Isaykina, Olesya Y.; Pokrovskaya, Mariya S.; Vygodin, Vladimir A.; Ozerova, Irina N.; Skvortsov, Dmitry A.; Boytsov, Sergey A.

2017-01-01

Background: Increased arterial stiffness (AS), intima-media thickness (IMT), and the presence of atherosclerotic plaques (PP) have been considered as important aspects of vascular aging. It is well documented that the cardiovascular system is an important target organ for growth hormone (GH) and insulin-like growth factor (IGF)-1 in humans, and GH /IGF-1 deficiency significantly increases the risk for cardiovascular diseases (CVD). The telomere length of peripheral blood leukocytes (LTL) is a biomarker of cellular senescence and that has been proposed as an independent predictor of (CVD). The aim of this study is to determine the role of GH/IGF-1, LTL and their interaction cardiovascular risk factors (CVRF) in the vascular aging. Methods: The study group included 303 ambulatory participants free of known CVD (104 males and 199 females) with a mean age of 51.8 ± 13.3 years. All subjects had one or more CVRF [age, smoking, arterial hypertension, obesity, dyslipidemia, fasting hyperglycemia, insulin resistance—HOMA (homeostatic model assessment) >2.5, or high glycated hemoglobin]. The study sample was divided into the two groups according to age as “younger” (m ≤ 45 years, f ≤ 55 years) and “older” (m > 45 years, f > 55 years). IMT and PP were determined by ultrasonography, AS was determined by measuring the carotid-femoral pulse wave velocity (c-f PWV) using the SphygmoCor system (AtCor Medical). LTL was determined by PCR. Serum IGF-1 and GH concentrations we measured by immunochemiluminescence analysis. Results: Multiple linear regression analysis with adjustment for CVRF indicated that HOMA, GH, IGF-1, and LTL had an independent relationship with all the arterial wall parameters investigated in the younger group. In the model with c-f PWV as a dependent variable, p < 0.001 for HOMA, p = 0.03 for GH, and p = 0.004 for LTL. In the model with IMT as a dependent variable, p = 0.0001 for HOMA, p = 0.044 for GH, and p = 0.004 for IGF-1. In the model with the number of plaques as a dependent variable, p = 0.0001 for HOMA, and p = 0.045 for IGF-1. In the older group, there were no independent significant associations between GH/IGF-1, LTL, HOMA, and arterial wall characteristics. Conclusions: GH/IGF-1, IR, HOMA, and LTL were the important parameters of arterial aging in younger healthy participants. PMID:29375617

Shorter telomere length in Europeans than in Africans due to polygenetic adaptation.

PubMed

Hansen, Matthew E B; Hunt, Steven C; Stone, Rivka C; Horvath, Kent; Herbig, Utz; Ranciaro, Alessia; Hirbo, Jibril; Beggs, William; Reiner, Alexander P; Wilson, James G; Kimura, Masayuki; De Vivo, Immaculata; Chen, Maxine M; Kark, Jeremy D; Levy, Daniel; Nyambo, Thomas; Tishkoff, Sarah A; Aviv, Abraham

2016-06-01

Leukocyte telomere length (LTL), which reflects telomere length in other somatic tissues, is a complex genetic trait. Eleven SNPs have been shown in genome-wide association studies to be associated with LTL at a genome-wide level of significance within cohorts of European ancestry. It has been observed that LTL is longer in African Americans than in Europeans. The underlying reason for this difference is unknown. Here we show that LTL is significantly longer in sub-Saharan Africans than in both Europeans and African Americans. Based on the 11 LTL-associated alleles and genetic data in phase 3 of the 1000 Genomes Project, we show that the shifts in allele frequency within Europe and between Europe and Africa do not fit the pattern expected by neutral genetic drift. Our findings suggest that differences in LTL within Europeans and between Europeans and Africans is influenced by polygenic adaptation and that differences in LTL between Europeans and Africans might explain, in part, ethnic differences in risks for human diseases that have been linked to LTL. © The Author 2016. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Depressive and anxiety disorders and short leukocyte telomere length: mediating effects of metabolic stress and lifestyle factors.

PubMed

Révész, D; Verhoeven, J E; Milaneschi, Y; Penninx, B W J H

2016-08-01

Depressive and anxiety disorders are associated with shorter leukocyte telomere length (LTL), an indicator of cellular aging. It is, however, unknown which pathways underlie this association. This study examined the extent to which lifestyle factors and physiological changes such as inflammatory or metabolic alterations mediate the relationship. We applied mediation analysis techniques to data from 2750 participants of the Netherlands Study of Depression and Anxiety. LTL was assessed using quantitative polymerase chain reaction. Independent variables were current depressive (30-item Inventory of Depressive Symptoms - Self Report) and anxiety (21-item Beck's Anxiety Inventory) symptoms and presence of a depressive or anxiety disorder diagnosis based on DSM-IV; mediator variables included physiological stress systems, metabolic syndrome components and lifestyle factors. Short LTL was associated with higher symptom severity (B = -2.4, p = 0.002) and current psychiatric diagnosis (B = -63.3, p = 0.024). C-reactive protein, interleukin-6, waist circumference, triglycerides, high-density lipoprotein cholesterol and cigarette smoking were significant mediators in the relationship between psychopathology and LTL. When all significant mediators were included in one model, the effect sizes of the relationships between LTL and symptom severity and current diagnosis were reduced by 36.7 and 32.7%, respectively, and the remaining direct effects were no longer significant. Pro-inflammatory cytokines, metabolic alterations and cigarette smoking are important mediators of the association between depressive and anxiety disorders and LTL. This calls for future research on intervention programs that take into account lifestyle changes in mental health care settings.

Telomere length is inversely correlated with urinary stress hormone levels in healthy controls but not in un-medicated depressed individuals-preliminary findings.

PubMed

Fair, Brittany; Mellon, Synthia H; Epel, Elissa S; Lin, Jue; Révész, Dóra; Verhoeven, Josine E; Penninx, Brenda W; Reus, Victor I; Rosser, Rebecca; Hough, Christina M; Mahan, Laura; Burke, Heather M; Blackburn, Elizabeth H; Wolkowitz, Owen M

2017-08-01

Leukocyte telomere length (LTL) is a biomarker of cellular aging affected by chronic stress. The relationship of LTL to the stress hormones, cortisol and catecholamines, is unclear, as are possible differences between healthy controls (HC) and individuals with Major Depressive Disorder (MDD). This small pilot study is the first to examine the relationship between cortisol, catecholamines and LTL specifically in un-medicated MDD in comparison with HC. Participants included 16 un-medicated MDD subjects and 15 HC for assay of LTL, 12-hour overnight urinary free cortisol and catecholamine levels. LTL, cortisol and catecholamine levels did not significantly differ between groups. In HC, a hierarchical regression analysis indicated that higher levels of cortisol were correlated with shorter LTL (p=0.003) above and beyond age and sex. Higher catecholamine levels were nearly-significant with shorter LTL (p=0.055). Neither hormone was correlated with shorter LTL in MDD (p's>0.28). To assess a possible cumulative effect of stress hormone activation, a summary score was calculated for each subject based on the number of stress hormone levels above the median for that group (HC or MDD). A significant inverse graded relationship was observed between LTL and the number of activated systems in HC (p=0.001), but not in MDD (p=0.96). This pilot study provides preliminary evidence that stress hormone levels, especially cortisol, are inversely related to LTL in HC, but not in un-medicated MDD. Clarification of these relationships in larger samples could aid in understanding differential mechanisms underlying stress-related cellular aging in healthy and depressed populations. Copyright © 2017 Elsevier Inc. All rights reserved.

Sex difference in leukocyte telomere length is ablated in opposite-sex co-twins

PubMed Central

Benetos, Athanase; Dalgård, Christine; Labat, Carlos; Kark, Jeremy D; Verhulst, Simon; Christensen, Kaare; Kimura, Masayuki; Horvath, Kent; Kyvik, Kirsten Ohm; Aviv, Abraham

2014-01-01

Background: In eutherian mammals and in humans, the female fetus may be masculinized while sharing the intra-uterine environment with a male fetus. Telomere length (TL), as expressed in leukocytes, is heritable and is longer in women than in men. The main determinant of leukocyte TL (LTL) is LTL at birth. However, LTL is modified by age-dependent attrition. Methods: We studied LTL dynamics (LTL and its attrition) in adult same-sex (monozygotic, n = 268; dizygotic, n = 308) twins and opposite-sex (n = 144) twins. LTL was measured by Southern blots of the terminal restriction fragments. Results: We observed that in same-sex (both monozygotic and dizygotic) twins, as reported in singletons, LTL was longer in females than in males [estimate ± standard error (SE):163 ± 63 bp, P < 0.01]. However, in opposite-sex twins, female LTL was indistinguishable from that of males (−31 ± 52 bp, P = 0.6), whereas male LTL was not affected. Findings were similar when the comparison was restricted to opposite-sex and same-sex dizygotic twins (females relative to males: same-sex: 188 ± 90 bp, P < 0.05; other-sex: −32 ± 64 bp, P = 0.6). Conclusions: These findings are compatible with masculinization of the female fetus in opposite-sex twins. They suggest that the sex difference in LTL, seen in the general population, is largely determined in utero, perhaps by the intrauterine hormonal environment. Further studies in newborn twins are warranted to test this thesis. PMID:25056338

The effect of the severity of obstructive sleep apnea syndrome on telomere length.

PubMed

Tempaku, Priscila Farias; Mazzotti, Diego Robles; Hirotsu, Camila; Andersen, Monica Levy; Xavier, Gabriela; Maurya, Pawan Kumar; Rizzo, Lucas Bortolotto; Brietzke, Elisa; Belangero, Sintia Iole; Bittencourt, Lia; Tufik, Sergio

2016-10-25

Aging is associated with an increase in the prevalence of obstructive sleep apnea syndrome (OSAS) as well as the shortening of telomeres. It is known that OSAS-related factors are stimuli that can contribute to the acceleration of cellular senescence. Thus, the present study aimed to compare the leukocyte telomere length (LTL) between OSAS patients and controls, as well as to verify the correlation between LTL and sleep parameters. We used DNA extracted of 928 individuals from EPISONO to measure the LTL by the quantitative real-time polymerase chain reaction. All individuals were subjected to one full-night polysomnography. LTL was significantly shorter in OSAS patients compared to controls. The results showed negative correlations between LTL and the following variables: apnea-hypopnea index, respiratory disturbance index, desaturation index and wake after sleep onset. LTL was positively correlated with sleep efficiency, total sleep time, basal, minimum and maximum oxygen saturation. Lastly, it was observed that OSAS severity was associated with shorter LTL even after adjusting for sex, age, years of schooling, body mass index, diabetes, stroke and heart attack. In conclusion, our study indicates the presence of an association between LTL and OSAS and a significant impact of severity of OSAS in telomeres shortening.

Childhood Personality, Betrayal Trauma, and Leukocyte Telomere Length in Adulthood: A Lifespan Perspective on Conscientiousness and Betrayal Traumas as Predictors of a Biomarker of Cellular Aging.

PubMed

Edmonds, Grant W; Hampson, Sarah E; Côté, Hélène C F; Hill, Patrick L; Klest, Bridget

2016-01-01

Conscientiousness is associated with longevity. As such, identifying the biological pathways linking personality to mortality is important. This study employs longitudinal data spanning >40 years to test prospective associations with Leukocyte Telomere Length (LTL), a potential marker of cellular aging. Because telomeres shorten over time, and are sensitive to oxidative stress, shorter LTL may reflect cumulative damage associated with negative health behaviors and past stressful events. We investigated childhood conscientiousness as a protective factor, expecting an association with longer LTL in adulthood, possibly reflecting slower LTL shortening. Potential lifespan pathways involving childhood trauma, smoking behaviors, and Body Mass Index (BMI) were explored. Childhood conscientiousness showed a small raw association with LTL ( r = .08, p = .04), although this effect did not persist when controlling for age and sex. Despite this lack of a direct effect on LTL, we detected an indirect effect operating jointly through BMI and smoking. Higher rates of childhood betrayal trauma were associated with shorter LTL. Contrary to our hypothesis that conscientiousness would buffer this effect, we found evidence for an interaction with childhood betrayal traumas where the association between childhood betrayal traumas and LTL was larger for those higher on conscientiousness in childhood.

Childhood Personality, Betrayal Trauma, and Leukocyte Telomere Length in Adulthood: A Lifespan Perspective on Conscientiousness and Betrayal Traumas as Predictors of a Biomarker of Cellular Aging

PubMed Central

Edmonds, Grant W.; Hampson, Sarah E.; Côté, Hélène C. F.; Hill, Patrick L.; Klest, Bridget

2016-01-01

Conscientiousness is associated with longevity. As such, identifying the biological pathways linking personality to mortality is important. This study employs longitudinal data spanning >40 years to test prospective associations with Leukocyte Telomere Length (LTL), a potential marker of cellular aging. Because telomeres shorten over time, and are sensitive to oxidative stress, shorter LTL may reflect cumulative damage associated with negative health behaviors and past stressful events. We investigated childhood conscientiousness as a protective factor, expecting an association with longer LTL in adulthood, possibly reflecting slower LTL shortening. Potential lifespan pathways involving childhood trauma, smoking behaviors, and Body Mass Index (BMI) were explored. Childhood conscientiousness showed a small raw association with LTL (r = .08, p = .04), although this effect did not persist when controlling for age and sex. Despite this lack of a direct effect on LTL, we detected an indirect effect operating jointly through BMI and smoking. Higher rates of childhood betrayal trauma were associated with shorter LTL. Contrary to our hypothesis that conscientiousness would buffer this effect, we found evidence for an interaction with childhood betrayal traumas where the association between childhood betrayal traumas and LTL was larger for those higher on conscientiousness in childhood. PMID:28018048

Telomere length in the two extremes of abnormal fetal growth and the programming effect of maternal arterial hypertension.

PubMed

Tellechea, Mariana; Gianotti, Tomas Fernandéz; Alvariñas, Jorge; González, Claudio D; Sookoian, Silvia; Pirola, Carlos J

2015-01-19

We tested the hypothesis that leukocyte telomere length (LTL) is associated with birth weight in both extremes of abnormal fetal growth: small (SGA) and large for gestational age newborns (LGA). Clinical and laboratory variables of the mothers and the neonates were explored; 45 newborns with appropriate weight for gestational age (AGA), 12 SGA and 12 LGA were included. Whether the differences might be explained by variation in OBFC1 (rs9419958) and CTC1 (rs3027234) genes associated with LTL was determined. A significant association between birth weight and LTL was observed; LTL was significantly shorter in LGA newborns (1.01 ± 0.12) compared with SGA (1.73 ± 0.19) p < 0.005, mean ± SE. Maternal (Spearman R = -0.6, p = 0.03) and neonatal LTL (R = -0.25, p = 0.03) were significantly and inversely correlated with maternal history of arterial hypertension in previous gestations. Neonatal LTL was not significantly associated with either rs9419950 or rs3027234, suggesting that the association between neonatal LTL and birth weight is not influenced by genetic variation in genes that modify the interindividual LTL. In conclusion, telomere biology seems to be modulated by abnormal fetal growth; modifications in telomere length might be programmed by an adverse environment in utero.

Correlated responses in growth, carcass, and meat quality traits to divergent selection for testosterone production in pigs.

PubMed

Bender, J M; See, M T; Hanson, D J; Lawrence, T E; Cassady, J P

2006-06-01

The objective of this project was to characterize changes in growth, carcass yield, and meat quality traits in castrates and gilts in response to divergent selection for testosterone production. In generation 21, endogenous testosterone concentrations in Duroc boars of the high (HTL) and low (LTL) testosterone lines averaged 49.0 and 27.8 ng/mL (P < 0.01), respectively. Eight LTL and 10 HTL boars were used to sire 29 LTL and 33 HTL litters. To remove the effects of inbreeding, these same boars were mated to females of a Large White x Landrace composite (WC) to generate 11 WC by LTL litters (WLT) and 23 WC by HTL litters (WHT). Castrates and gilts were then allotted to LTL (n = 53), HTL (n = 61), WLT (n = 102), and WHT (n = 101) for testing. Growth and carcass traits analyzed included days to 114 kg (D114), ADG, backfat adjusted to 114 kg (ABF), LM area adjusted to 114 kg and predicted percent lean (PPL). Fat-O-Meater data collected were adjusted fat depth (AFD), adjusted loin depth, and percent lean. Meat quality traits characterized at 24 h postmortem included marbling score, percent lipid, pH, drip loss, color score, and Minolta L*, a*, and b*. Data were analyzed with a mixed model including fixed effects of line, mating type (purebred or crossbred), sex, and the random effect of sire nested within line. All possible interactions among fixed effects were tested. The HTL had fewer D114 (P < 0.05), greater ADG (P < 0.01), greater ABF (P < 0.01), and lower PPL (P < 0.01) than LTL. The WHT and WLT did not differ for D114, ADG, or ABF. The WHT had smaller LM area adjusted to 114 kg (P < 0.05) and greater drip loss (P < 0.05) than WLT. The WLT had lower adjusted loin depth (P < 0.05) than LTL and HTL. The LTL and HTL had greater subjective scores for marbling (P < 0.05) compared with WLT and WHT. The least squares mean for percent lipid for HTL and LTL was 4.00. The WHT had greater means for L*, a*, and b* (P < 0.05) than WLT. Pigs selected for increased testosterone production grew faster and produced fatter carcasses than pigs selected for decreased testosterone. Changes in growth, carcass yield, and meat quality traits were detected in castrates and gilts in response to divergent selection for testosterone production.

Metabolic profiles of biological aging in American Indians: the Strong Heart Family Study.

PubMed

Zhao, Jinying; Zhu, Yun; Uppal, Karan; Tran, ViLinh T; Yu, Tianwei; Lin, Jue; Matsuguchi, Tet; Blackburn, Elizabeth; Jones, Dean; Lee, Elisa T; Howard, Barbara V

2014-03-01

Short telomere length, a marker of biological aging, has been associated with age-related metabolic disorders. Telomere attrition induces profound metabolic dysfunction in animal models, but no study has examined the metabolome of telomeric aging in human. Here we studied 423 apparently healthy American Indians participating in the Strong Family Heart Study. Leukocyte telomere length (LTL) was measured by qPCR. Metabolites in fasting plasma were detected by untargeted LC/MS. Associations of LTL with each metabolite and their combined effects were examined using generalized estimating equation adjusting for chronological age and other aging-related factors. Multiple testing was corrected using the q-value method (q<0.05). Of the 1,364 distinct m/z features detected, nineteen metabolites in the classes of glycerophosphoethanolamines, glycerophosphocholines, glycerolipids, bile acids, isoprenoids, fatty amides, or L-carnitine ester were significantly associated with LTL, independent of chronological age and other aging-related factors. Participants with longer (top tertile) and shorter (bottom tertile) LTL were clearly separated into distinct groups using a multi-marker score comprising of all these metabolites, suggesting that these newly detected metabolites could be novel metabolic markers of biological aging. This is the first study to interrogate the human metabolome of telomeric aging. Our results provide initial evidence for a metabolic control of LTL and may reveal previously undescribed new roles of various lipids in the aging process.

Impact of biological aging on arterial aging in American Indians: findings from the Strong Heart Family Study.

PubMed

Peng, Hao; Zhu, Yun; Yeh, Fawn; Cole, Shelley A; Best, Lyle G; Lin, Jue; Blackburn, Elizabeth; Devereux, Richard B; Roman, Mary J; Lee, Elisa T; Howard, Barbara V; Zhao, Jinying

2016-08-01

Telomere length, a marker of biological aging, has been associated with cardiovascular disease (CVD). Increased arterial stiffness, an indicator of arterial aging, predicts adverse CVD outcomes. However, the relationship between telomere length and arterial stiffness is less well studied. Here we examined the cross-sectional association between leukocyte telomere length (LTL) and arterial stiffness in 2,165 American Indians in the Strong Heart Family Study (SHFS). LTL was measured by qPCR. Arterial stiffness was assessed by stiffness index β. The association between LTL and arterial stiffness was assessed by generalized estimating equation model, adjusting for sociodemographics (age, sex, education level), study site, metabolic factors (fasting glucose, lipids, systolic blood pressure, and kidney function), lifestyle (BMI, smoking, drinking, and physical activity), and prevalent CVD. Results showed that longer LTL was significantly associated with a decreased arterial stiffness (β=-0.070, P=0.007). This association did not attenuate after further adjustment for hsCRP (β=-0.071, P=0.005) or excluding participants with overt CVD (β=-0.068, P=0.012), diabetes (β=-0.070, P=0.005), or chronic kidney disease (β=-0.090, P=0.001). In summary, shorter LTL was significantly associated with an increased arterial stiffness, independent of known risk factors. This finding may shed light on the potential role of biological aging in arterial aging in American Indians.

Research on vehicles and cargos matching model based on virtual logistics platform

NASA Astrophysics Data System (ADS)

Zhuang, Yufeng; Lu, Jiang; Su, Zhiyuan

2018-04-01

Highway less than truckload (LTL) transportation vehicles and cargos matching problem is a joint optimization problem of typical vehicle routing and loading, which is also a hot issue of operational research. This article based on the demand of virtual logistics platform, for the problem of the highway LTL transportation, the matching model of the idle vehicle and the transportation order is set up and the corresponding genetic algorithm is designed. Then the algorithm is implemented by Java. The simulation results show that the solution is satisfactory.

Interactions between UCP2 SNPs and telomere length exist in the absence of diabetes or pre-diabetes

PubMed Central

Zhou, Yuling; Simmons, David; Hambly, Brett D.; McLachlan, Craig S.

2016-01-01

Mitochondrial uncoupling protein 2 (UCP2) can affect oxidative stress levels. UCP2 polymorphisms are associated with leukocyte telomere length (LTL) in Type 2 Diabetes, which also induces considerable background oxidative stress. The effects of UCP2 polymorphisms on LTL in populations without diabetes have not been well described. Our aims are to evaluate the interaction between LTL and UCP2 polymorphisms in 950 subjects without diabetes. The monochrome multiplex quantitative PCR method was used to measure relative LTL. Taqman SNP genotyping assay was applied to genotypes for UCP2 rs659366 and rs660339. We found shorter LTL associated with increased age (P < 0.001) and triglyceride levels (P = 0.041). After adjustment for cardiovascular risk factors, rs659336 GG genotype carriers demonstrated a shorter LTL (1.257 ± 0.186), compared to GA carriers (1.288 ± 0.230, P = 0.022) and AA carriers (1.314 ± 0.253, P = 0.002). LTL was shorter in the CC rs660339 genotype (1.254 ± 0.187) compared to TT (1.297 ± 0.242, P = 0.007) and CT carriers (1.292 ± 0.229, P = 0.016). The T allele of rs660339 is associated with a longer LTL of approximately 0.04 compared to CC homozygotes. Thus, UCP2 rs659366 A allele and rs660339 T allele are both related to longer LTL in subjects without diabetes, independent of cardiovascular risk factors. PMID:27615599

Emotions and family interactions in childhood: Associations with leukocyte telomere length emotions, family interactions, and telomere length.

PubMed

Robles, Theodore F; Carroll, Judith E; Bai, Sunhye; Reynolds, Bridget M; Esquivel, Stephanie; Repetti, Rena L

2016-01-01

Conceptualizations of links between stress and cellular aging in childhood suggest that accumulating stress predicts shorter leukocyte telomere length (LTL). At the same time, several models suggest that emotional reactivity to stressors may play a key role in predicting cellular aging. Using intensive repeated measures, we tested whether exposure or emotional "reactivity" to conflict and warmth in the family were related to LTL. Children (N=39; 30 target children and 9 siblings) between 8 and 13 years of age completed daily diary questionnaires for 56 consecutive days assessing daily warmth and conflict in the marital and the parent-child dyad, and daily positive and negative mood. To assess exposure to conflict and warmth, diary scale scores were averaged over the 56 days. Mood "reactivity" was operationalized by using multilevel modeling to generate estimates of the slope of warmth or conflict scores (marital and parent-child, separately) predicting same-day mood for each individual child. After diary collection, a blood sample was collected to determine LTL. Among children aged 8-13 years, a stronger association between negative mood and marital conflict, suggesting greater negative mood reactivity to marital conflict, was related to shorter LTL (B=-1.51, p<.01). A stronger association between positive mood and marital affection, suggesting positive mood reactivity, was related to longer LTL (B=1.15, p<.05). These effects were independent of exposure to family and marital conflict and warmth, and positive and negative mood over a two-month period. To our knowledge, these findings, although cross-sectional, represent the first evidence showing that link between children's affective responses and daily family interactions may have implications for telomere length. Copyright © 2015 Elsevier Ltd. All rights reserved.

Cross-sectional Associations between Exposure to Persistent Organic Pollutants and Leukocyte Telomere Length among U.S. Adults in NHANES, 2001–2002

PubMed Central

Mitro, Susanna D.; Birnbaum, Linda S.; Needham, Belinda L.; Zota, Ami R.

2015-01-01

Background: Exposure to persistent organic pollutants (POPs) such as dioxins, furans, and polychlorinated biphenyls (PCBs) may influence leukocyte telomere length (LTL), a biomarker associated with chronic disease. In vitro research suggests dioxins may bind to the aryl hydrocarbon receptor (AhR) and induce telomerase activity, which elongates LTL. However, few epidemiologic studies have investigated associations between POPs and LTL. Objectives: We examined the association between 18 PCBs, 7 dioxins, and 9 furans and LTL among 1,330 U.S. adults from NHANES 2001–2002. Methods: We created three summed POP metrics based on toxic equivalency factor (TEF), a potency measure including affinity for the AhR: a) non–dioxin-like PCBs (composed of 10 non–dioxin-like PCBs; no AhR affinity and no TEF); b) non-ortho PCBs (composed of 2 non–ortho-substituted PCBs with high TEFs); and c) toxic equivalency (TEQ) (composed of 7 dioxins, 9 furans, 2 non–ortho-substituted PCBs, and 6 mono–ortho-substituted PCBs; weighted by TEF). We tested the association between each metric and LTL using linear regression, adjusting for demographics, blood cell count and distribution, and another metric with a different TEF (i.e., non-ortho PCBs and TEQ adjusted for non–dioxin-like PCBs; non–dioxin-like PCBs adjusted for non-ortho PCBs). Results: In adjusted models, each doubling of serum concentrations of non-ortho PCBs and TEQ was associated with 3.74% (95% CI: 2.10, 5.40) and 5.29% (95% CI: 1.66, 9.05) longer LTLs, respectively. Compared with the lowest quartile, the highest quartile of exposure was associated with 9.16% (95% CI: 2.96, 15.73) and 7.84% (95% CI: –0.53, 16.92) longer LTLs, respectively. Non–dioxin-like PCBs were not associated with LTL. Conclusions: POPs with high TEFs and AhR affinity were associated with longer LTL. Because many dioxin-associated cancers are also associated with longer LTL, these results may provide insight into the mechanisms underlying PCB- and dioxin-related carcinogenesis. Citation: Mitro SD, Birnbaum LS, Needham BL, Zota AR. 2016. Cross-sectional associations between exposure to persistent organic pollutants and leukocyte telomere length among U.S. adults in NHANES, 2001–2002. Environ Health Perspect 124:651–658; http://dx.doi.org/10.1289/ehp.1510187 PMID:26452299

Treatment with docetaxel in combination with Aneustat leads to potent inhibition of metastasis in a patient-derived xenograft model of advanced prostate cancer

PubMed Central

Qu, Sifeng; Ci, Xinpei; Xue, Hui; Dong, Xin; Hao, Jun; Lin, Dong; Clermont, Pier-Luc; Wu, Rebecca; Collins, Colin C; Gout, Peter W; Wang, Yuzhuo

2018-01-01

Background: Docetaxel used for first-line treatment of advanced prostate cancer (PCa) is only marginally effective. We previously showed, using the LTL-313H subrenal capsule patient-derived metastatic PCa xenograft model, that docetaxel combined with Aneustat (OMN54), a multivalent plant-derived therapeutic, led to marked synergistic tumour growth inhibition. Here, we investigated the effect of docetaxel+Aneustat on metastasis. Methods: C4-2 cells were incubated with docetaxel, Aneustat and docetaxel+Aneustat to assess effects on cell migration. The LTL-313H model, similarly treated, was analysed for effects on lung micro-metastasis and kidney invasion. The LTL-313H gene expression profile was compared with profiles of PCa patients (obtained from Oncomine) and subjected to IPA to determine involvement of cancer driver genes. Results: Docetaxel+Aneustat markedly inhibited C4-2 cell migration and LTL-313H lung micro-metastasis/kidney invasion. Oncomine analysis indicated that treatment with docetaxel+Aneustat was associated with improved patient outcome. The drug combination markedly downregulated expression of cancer driver genes such as FOXM1 (and FOXM1-target genes). FOXM1 overexpression reduced the anti-metastatic activity of docetaxel+Aneustat. Conclusions: Docetaxel+Aneustat can inhibit PCa tissue invasion and metastasis. This activity appears to be based on reduced expression of cancer driver genes such as FOXM1. Use of docetaxel+Aneustat may provide a new, more effective regimen for therapy of metastatic PCa. PMID:29381682

Telomere length and early trauma in schizophrenia.

PubMed

Riley, Gabriella; Perrin, Mary; Vaez-Azizi, Leila M; Ruby, Eugene; Goetz, Raymond R; Dracxler, Roberta; Walsh-Messinger, Julie; Keefe, David L; Buckley, Peter F; Szeszko, Philip R; Malaspina, Dolores

2018-04-02

Childhood trauma is emerging as a risk factor for schizophrenia, but its mechanism with respect to etiology is unknown. One possible pathway is through leucocyte telomere length (LTL) shortening, a measure of cellular aging associated with trauma. This study examined early trauma and LTL shortening in schizophrenia and considered sex effects. The early trauma inventory (ETI) was administered to 48 adults with DSM-5 schizophrenia and 18 comparison participants. LTL was measured using qPCR. Cases had significantly more global trauma (F=4.10, p<0.01) and traumatic events (F=11.23, p<0.001), but case and control groups had similar LTL (1.91±0.74 and 1.83±0.62: p=0.68). The association of early trauma and LTL differed by sex in cases and controls (Fisher's R: Z<0.05). Significant negative associations were shown in male cases and, conversely, in female controls. For example, physical punishment was associated LTL shortening in males' cases (r=-0.429, p<01). Only female controls showed significant telomere shortening in association with early trauma. This data confirms the substantial excess of early trauma among schizophrenia cases. There were significant sex-differences in the relationship of the trauma to LTL, with only male cases showing the expected shortening. There were converse sex effects in the control group. Mean LTL was notably similar in cases and controls, despite the trauma-related shortening in male cases, cigarette smoking, older age and chronic illness of the cases. Factors may lengthen LTL in some schizophrenia cases. The converse sex differences in the cases are consistent with findings defective sexual differentiation in schizophrenia, consistent with other findings in the field. Copyright © 2018 Elsevier B.V. All rights reserved.

Discrimination, mental health, and leukocyte telomere length among African American men.

PubMed

Chae, David H; Epel, Elissa S; Nuru-Jeter, Amani M; Lincoln, Karen D; Taylor, Robert Joseph; Lin, Jue; Blackburn, Elizabeth H; Thomas, Stephen B

2016-01-01

African American men in the US experience disparities across multiple health outcomes. A common mechanism underlying premature declines in health may be accelerated biological aging, as reflected by leukocyte telomere length (LTL). Racial discrimination, a qualitatively unique source of social stress reported by African American men, in tandem with poor mental health, may negatively impact LTL in this population. The current study examined cross-sectional associations between LTL, self-reported racial discrimination, and symptoms of depression and anxiety among 92 African American men 30-50 years of age. LTL was measured in kilobase pairs using quantitative polymerase chain reaction assay. Controlling for sociodemographic factors, greater anxiety symptoms were associated with shorter LTL (b=-0.029, standard error [SE]=0.014; p<0.05). There were no main effects of racial discrimination or depressive symptoms on LTL, but we found evidence for a significant interaction between the two (b=0.011, SE=0.005; p<0.05). Racial discrimination was associated with shorter LTL among those with lower levels of depressive symptoms. Findings from this study highlight the role of social stressors and individual-level psychological factors for physiologic deterioration among African American men. Consistent with research on other populations, greater anxiety may reflect elevated stress associated with shorter LTL. Racial discrimination may represent an additional source of social stress among African American men that has detrimental consequences for cellular aging among those with lower levels of depression. Copyright © 2015 Elsevier Ltd. All rights reserved.

A Rewriting-Based Approach to Trace Analysis

NASA Technical Reports Server (NTRS)

Havelund, Klaus; Rosu, Grigore; Clancy, Daniel (Technical Monitor)

2002-01-01

We present a rewriting-based algorithm for efficiently evaluating future time Linear Temporal Logic (LTL) formulae on finite execution traces online. While the standard models of LTL are infinite traces, finite traces appear naturally when testing and/or monitoring red applications that only run for limited time periods. The presented algorithm is implemented in the Maude executable specification language and essentially consists of a set of equations establishing an executable semantics of LTL using a simple formula transforming approach. The algorithm is further improved to build automata on-the-fly from formulae, using memoization. The result is a very efficient and small Maude program that can be used to monitor program executions. We furthermore present an alternative algorithm for synthesizing probably minimal observer finite state machines (or automata) from LTL formulae, which can be used to analyze execution traces without the need for a rewriting system, and can hence be used by observers written in conventional programming languages. The presented work is part of an ambitious runtime verification and monitoring project at NASA Ames, called PATHEXPLORER, and demonstrates that rewriting can be a tractable and attractive means for experimenting and implementing program monitoring logics.

Synthesizing Dynamic Programming Algorithms from Linear Temporal Logic Formulae

NASA Technical Reports Server (NTRS)

Rosu, Grigore; Havelund, Klaus

2001-01-01

The problem of testing a linear temporal logic (LTL) formula on a finite execution trace of events, generated by an executing program, occurs naturally in runtime analysis of software. We present an algorithm which takes an LTL formula and generates an efficient dynamic programming algorithm. The generated algorithm tests whether the LTL formula is satisfied by a finite trace of events given as input. The generated algorithm runs in linear time, its constant depending on the size of the LTL formula. The memory needed is constant, also depending on the size of the formula.

Telomeres and cardiovascular disease risk: an update 2013.

PubMed

Nilsson, Peter M; Tufvesson, Hanna; Leosdottir, Margrét; Melander, Olle

2013-12-01

Leukocyte telomere length (LTL) has been regarded as a potential marker of biologic aging because it usually shortens in a predictable way with age. Recently, a growing interest in cardiovascular aging has led to a number of new epidemiologic studies investigating LTL in various disease conditions. Some methodological problems exist because there are different methods available to determine LTL, and standardization is much needed. For example, in the majority of studies, patients with early-onset coronary heart disease have been shown to have shorter LTL. In addition, patients with diabetes mellitus complications tend to have shorter LTL than control subjects. On the other hand, increased left ventricular hypertrophy or mass is associated with longer LTL, and studies investigating hypertension have reported both shorter and longer LTL than found in normotensive control subjects. There is, therefore, a need for longitudinal studies to elucidate these complicated relationships further, to provide estimations of telomere attrition rates, and to overcome analytical problems when only cross-sectional studies are used. The understanding of cardiovascular aging and telomere biology may open up new avenues for interventions, such as stem cell therapy or agents that could retard this aging process over and beyond conventional risk factor control. Copyright © 2013 Mosby, Inc. All rights reserved.

Discrimination, Racial Bias, and Telomere Length in African-American Men

PubMed Central

Chae, David H.; Nuru-Jeter, Amani M.; Adler, Nancy E.; Brody, Gene H.; Lin, Jue; Blackburn, Elizabeth H.; Epel, Elissa S.

2013-01-01

Background Leukocyte telomere length (LTL) is an indicator of general systemic aging, with shorter LTL being associated with several chronic diseases of aging and earlier mortality. Identifying factors related to LTL among African Americans may yield insights into mechanisms underlying racial disparities in health. Purpose To test whether the combination of more frequent reports of racial discrimination and holding a greater implicit anti-black racial bias is associated with shorter LTL among African-American men. Methods Cross-sectional study of a community sample of 92 African-American men aged between 30 and 50 years. Participants were recruited from February to May 2010. Ordinary least squares regressions were used to examine LTL in kilobase pairs in relation to racial discrimination and implicit racial bias. Data analysis was completed in July 2013. Results After controlling for chronologic age, socioeconomic, and health-related characteristics, the interaction between racial discrimination and implicit racial bias was significantly associated with LTL (b= −0.10, SE=0.04, p=0.02). Those demonstrating a stronger implicit anti-black bias and reporting higher levels of racial discrimination had the shortest LTL. Household income-to-poverty threshold ratio was also associated with LTL (b=0.05, SE=0.02, p<0.01). Conclusions Results suggest that multiple levels of racism, including interpersonal experiences of racial discrimination and the internalization of negative racial bias, operate jointly to accelerate biological aging among African-American men. Societal efforts to address racial discrimination in concert with efforts to promote positive in-group racial attitudes may protect against premature biological aging in this population. PMID:24439343

Leukocyte telomere length dynamics in women and men: menopause vs age effects

PubMed Central

Dalgård, Christine; Benetos, Athanase; Verhulst, Simon; Labat, Carlos; Kark, Jeremy D; Christensen, Kaare; Kimura, Masayuki; Kyvik, Kirsten Ohm; Aviv, Abraham

2015-01-01

Background: A longer leukocyte telomere length (LTL) in women than men has been attributed to a slow rate of LTL attrition in women, perhaps due to high estrogen exposure during the premenopausal period. Methods: To test this premise we performed a longitudinal study (an average follow-up of 12 years) in a subset of the population-based Danish National Twin Registry. Participants consisted of 405 women, aged 37.5 (range 18.0–64.3) years, and 329 men, aged 38.8 (range 18.0–58.5) years, at baseline examination. Results: Women showed a longer LTL [kb ± standard error(SE)] than men (baseline: 7.01 ± 0.03 vs 6.87 ± 0.04; follow-up: 6.79 ± 0.03 vs 6.65 ± 0.03; both P = 0.005). Women displayed deceleration of LTL attrition (bp/years ± SE), as they transitioned from the premenopausal period (20.6 ± 1.0) through the perimenopausal period (16.5 ± 1.3) to the postmenopausal period (15.1 ± 1.7). Age was not associated with LTL attrition in women after statistical control for menopausal status. Men, in contrast, displayed a trend for age-dependent increase in the rate of LTL attrition, which differed significantly from the pattern in women (P for interaction = 0.01). Conclusions: Results indicate that the premenopausal period is expressed in a higher rate of LTL attrition than the postmenopausal period. They further suggest that the sex gap in LTL stems from earlier ages—the period of growth and development. The higher rate of LTL attrition in premenopausal women, we propose, might relate to estrogen-mediated increased turnover of erythrocytes, menstrual bleeding or both. PMID:26385867

Prenatal exposure to perfluoroalkyl and polyfluoroalkyl substances affects leukocyte telomere length in female newborns.

PubMed

Liu, Han; Chen, Qian; Lei, Lei; Zhou, Wei; Huang, Lisu; Zhang, Jun; Chen, Dan

2018-04-01

Evidence has shown that leukocyte telomere length (LTL) at birth is related to the susceptibility to various diseases in later life and the setting of newborn LTL is influenced by the intrauterine environment. Perfluoroalkyl and polyfluoroalkyl substances (PFASs), as a kind of persistent organic pollutants, are commonly used in commercial and domestic applications and are capable of crossing the maternal-fetal barrier during pregnancy. We hypothesized that intrauterine exposure to PFASs may affect fetal LTL by increasing oxidative stress. To verify this hypothesis, LTL, concentrations of PFASs and reactive oxygen species (ROS) were measured in umbilical cord blood of 581 newborns from a prospective cohort. Our results showed that there were interactions between PFOS/PFDA and sex on LTL and ROS. The LTL was significantly shorter (0.926 ± 0.053 vs 0.945 ± 0.054, P = .023 for PFOS; 0.919 ± 0.063 vs 0.940 ± 0.059, P = .011 for PFDA) and the ROS levels were extremely higher (252.9 ± 60.5 [M] vs 233.5 ± 53.6 [M], P = .031 for PFOS; 255.2 ± 62.9 [M] vs 232.9 ± 58.3 [M], P = .011 for PFDA) in the female newborns whose PFOS or PFDA concentrations fell in the upmost quartile compared with those in the lowest quartile after adjusting for potential confounders. ROS levels were inversely associated with LTL in female newborns (β = -1.42 × 10 -4 , P = .022). 13% of the effect of PFOS on female LTL was mediated through ROS approximately by the mediation analyses. However, in male newborns, no relationships among PFASs, ROS and LTL were observed. Our findings suggest a "programming" role of PFASs on fetal telomere biology system in females in intrauterine stage. Copyright © 2018 Elsevier Ltd. All rights reserved.

Socioeconomic Factors and Leukocyte Telomere Length In A Multi-Ethnic Sample: Findings From The Multi-Ethnic Study of Atherosclerosis (MESA)

PubMed Central

Carroll, Judith E.; Diez-Roux, Ana V.; Adler, Nancy E.; Seeman, Teresa E.

2012-01-01

Previous findings have linked lower socioeconomic status (SES) with elevated morbidity and mortality. Leukocyte telomere length (LTL), which also has been associated with age-related disease morbidity and mortality, is a marker of aging at the cellular level, making it a valuable early biomarker of risk and an indicator of biological age. It is hypothesized that SES will be associated with LTL, indicating that SES influences disease risk by accelerating biological aging. In the present sample we test for associations of childhood SES and adult SES (i.e. education, income, home ownership) with LTL, and examine whether these associations vary by racial/ethnic group. Analyses on 963 subjects (18.7% White, 53% Hispanics, and 28.5% African American) from the Stress ancillary study of the Multi-Ethnic Study of Atherosclerosis revealed a significant difference in LTL between home owners and renters in Hispanic and White participants (p < .05), but not amongst African Americans (p = .98). There were no linear associations of adult education or family income with LTL, however, there was an inverse association between father’s education and LTL (p = .03). These findings suggest that for Whites and Hispanics renting vs. owning a home is associated with an older biological age; however we did not replicate previous findings linking education with LTL. PMID:23142704

Relative Leukocyte Telomere Length, Hematological Parameters and Anemia - Data from the Berlin Aging Study II (BASE-II).

PubMed

Meyer, Antje; Salewsky, Bastian; Buchmann, Nikolaus; Steinhagen-Thiessen, Elisabeth; Demuth, Ilja

2016-01-01

The length of the chromosome ends, telomeres, is widely accepted as a biomarker of aging. However, the dynamic of the relationship between telomere length and hematopoietic parameters in the normal aging process, which is of particular interest with respect to age-related anemia, is not well understood. We have analyzed the relationship between relative leukocyte telomere length (rLTL) and several hematological parameters in the older group of the Berlin Aging Study II (BASE-II) participants. This paper also compares rLTL between both BASE-II age groups (22-37 and 60-83 years). Genomic DNA was extracted from peripheral blood leukocytes of BASE-II participants and used to determine rLTL by a quantitative PCR protocol. Standard methods were used to determine blood parameters, and the WHO criteria were used to identify anemic participants. Telomere length data were available for 444 younger participants (28.4 ± 3.1 years old; 52% women) and 1,460 older participants (68.2 ± 3.7 years old; 49.4% women). rLTL was significantly shorter in BASE-II participants of the older group (p = 3.7 × 10-12) and in women (p = 4.2 × 10-31). rLTL of older men exhibited a statistically significant, positive partial correlation with mean corpuscular hemoglobin (MCH; p = 0.012) and MCH concentration (p = 0.002). While these correlations were only observed in men, the rLTL of older women was negatively correlated with the number of thrombocytes (p = 0.015) in the same type of analysis. Among all older participants, 6% met the criteria to be categorized as 'anemic'; however, there was no association between anemia and rLTL. In the present study, we have detected isolated correlations between rLTL and hematological parameters; however, in all cases, rLTL explained only a small part of the variation of the analyzed parameters. In disagreement with some other studies showing similar data, we interpret the association between rLTL and some of the hematological parameters studied here to be at most marginal. This applies also to the role of rLTL in anemia, at least in the age group investigated here. Since BASE-II is yet another large cohort in which women have on average shorter telomeres than men, this finding will be addressed in the discussion with respect to the ongoing debate on gender differences in telomere length. © 2016 S. Karger AG, Basel.

Genome-wide association identifies OBFC1 as a locus involved in human leukocyte telomere biology.

PubMed

Levy, Daniel; Neuhausen, Susan L; Hunt, Steven C; Kimura, Masayuki; Hwang, Shih-Jen; Chen, Wei; Bis, Joshua C; Fitzpatrick, Annette L; Smith, Erin; Johnson, Andrew D; Gardner, Jeffrey P; Srinivasan, Sathanur R; Schork, Nicholas; Rotter, Jerome I; Herbig, Utz; Psaty, Bruce M; Sastrasinh, Malinee; Murray, Sarah S; Vasan, Ramachandran S; Province, Michael A; Glazer, Nicole L; Lu, Xiaobin; Cao, Xiaojian; Kronmal, Richard; Mangino, Massimo; Soranzo, Nicole; Spector, Tim D; Berenson, Gerald S; Aviv, Abraham

2010-05-18

Telomeres are engaged in a host of cellular functions, and their length is regulated by multiple genes. Telomere shortening, in the course of somatic cell replication, ultimately leads to replicative senescence. In humans, rare mutations in genes that regulate telomere length have been identified in monogenic diseases such as dyskeratosis congenita and idiopathic pulmonary fibrosis, which are associated with shortened leukocyte telomere length (LTL) and increased risk for aplastic anemia. Shortened LTL is observed in a host of aging-related complex genetic diseases and is associated with diminished survival in the elderly. We report results of a genome-wide association study of LTL in a consortium of four observational studies (n = 3,417 participants with LTL and genome-wide genotyping). SNPs in the regions of the oligonucleotide/oligosaccharide-binding folds containing one gene (OBFC1; rs4387287; P = 3.9 x 10(-9)) and chemokine (C-X-C motif) receptor 4 gene (CXCR4; rs4452212; P = 2.9 x 10(-8)) were associated with LTL at a genome-wide significance level (P < 5 x 10(-8)). We attempted replication of the top SNPs at these loci through de novo genotyping of 1,893 additional individuals and in silico lookup in another observational study (n = 2,876), and we confirmed the association findings for OBFC1 but not CXCR4. In addition, we confirmed the telomerase RNA component (TERC) as a gene associated with LTL (P = 1.1 x 10(-5)). The identification of OBFC1 through genome-wide association as a locus for interindividual variation in LTL in the general population advances the understanding of telomere biology in humans and may provide insights into aging-related disorders linked to altered LTL dynamics.

Discrimination, racial bias, and telomere length in African-American men.

PubMed

Chae, David H; Nuru-Jeter, Amani M; Adler, Nancy E; Brody, Gene H; Lin, Jue; Blackburn, Elizabeth H; Epel, Elissa S

2014-02-01

Leukocyte telomere length (LTL) is an indicator of general systemic aging, with shorter LTL being associated with several chronic diseases of aging and earlier mortality. Identifying factors related to LTL among African Americans may yield insights into mechanisms underlying racial disparities in health. To test whether the combination of more frequent reports of racial discrimination and holding a greater implicit anti-black racial bias is associated with shorter LTL among African-American men. Cross-sectional study of a community sample of 92 African-American men aged between 30 and 50 years. Participants were recruited from February to May 2010. Ordinary least squares regressions were used to examine LTL in kilobase pairs in relation to racial discrimination and implicit racial bias. Data analysis was completed in July 2013. After controlling for chronologic age and socioeconomic and health-related characteristics, the interaction between racial discrimination and implicit racial bias was significantly associated with LTL (b=-0.10, SE=0.04, p=0.02). Those demonstrating a stronger implicit anti-black bias and reporting higher levels of racial discrimination had the shortest LTL. Household income-to-poverty threshold ratio was also associated with LTL (b=0.05, SE=0.02, p<0.01). Results suggest that multiple levels of racism, including interpersonal experiences of racial discrimination and the internalization of negative racial bias, operate jointly to accelerate biological aging among African-American men. Societal efforts to address racial discrimination in concert with efforts to promote positive in-group racial attitudes may protect against premature biological aging in this population. © 2013 American Journal of Preventive Medicine Published by American Journal of Preventive Medicine All rights reserved.

Program Monitoring with LTL in EAGLE

NASA Technical Reports Server (NTRS)

Barringer, Howard; Goldberg, Allen; Havelund, Klaus; Sen, Koushik

2004-01-01

We briefly present a rule-based framework called EAGLE, shown to be capable of defining and implementing finite trace monitoring logics, including future and past time temporal logic, extended regular expressions, real-time and metric temporal logics (MTL), interval logics, forms of quantified temporal logics, and so on. In this paper we focus on a linear temporal logic (LTL) specialization of EAGLE. For an initial formula of size m, we establish upper bounds of O(m(sup 2)2(sup m)log m) and O(m(sup 4)2(sup 2m)log(sup 2) m) for the space and time complexity, respectively, of single step evaluation over an input trace. This bound is close to the lower bound O(2(sup square root m) for future-time LTL presented. EAGLE has been successfully used, in both LTL and metric LTL forms, to test a real-time controller of an experimental NASA planetary rover.

Linear Temporal Logic (LTL) Based Monitoring of Smart Manufacturing Systems.

PubMed

Heddy, Gerald; Huzaifa, Umer; Beling, Peter; Haimes, Yacov; Marvel, Jeremy; Weiss, Brian; LaViers, Amy

2015-01-01

The vision of Smart Manufacturing Systems (SMS) includes collaborative robots that can adapt to a range of scenarios. This vision requires a classification of multiple system behaviors, or sequences of movement, that can achieve the same high-level tasks. Likewise, this vision presents unique challenges regarding the management of environmental variables in concert with discrete, logic-based programming. Overcoming these challenges requires targeted performance and health monitoring of both the logical controller and the physical components of the robotic system. Prognostics and health management (PHM) defines a field of techniques and methods that enable condition-monitoring, diagnostics, and prognostics of physical elements, functional processes, overall systems, etc. PHM is warranted in this effort given that the controller is vulnerable to program changes, which propagate in unexpected ways, logical runtime exceptions, sensor failure, and even bit rot. The physical component's health is affected by the wear and tear experienced by machines constantly in motion. The controller's source of faults is inherently discrete, while the latter occurs in a manner that builds up continuously over time. Such a disconnect poses unique challenges for PHM. This paper presents a robotic monitoring system that captures and resolves this disconnect. This effort leverages supervisory robotic control and model checking with linear temporal logic (LTL), presenting them as a novel monitoring system for PHM. This methodology has been demonstrated in a MATLAB-based simulator for an industry inspired use-case in the context of PHM. Future work will use the methodology to develop adaptive, intelligent control strategies to evenly distribute wear on the joints of the robotic arms, maximizing the life of the system.

Developing Formal Correctness Properties from Natural Language Requirements

NASA Technical Reports Server (NTRS)

Nikora, Allen P.

2006-01-01

This viewgraph presentation reviews the rationale of the program to transform natural language specifications into formal notation.Specifically, automate generation of Linear Temporal Logic (LTL)correctness properties from natural language temporal specifications. There are several reasons for this approach (1) Model-based techniques becoming more widely accepted, (2) Analytical verification techniques (e.g., model checking, theorem proving) significantly more effective at detecting types of specification design errors (e.g., race conditions, deadlock) than manual inspection, (3) Many requirements still written in natural language, which results in a high learning curve for specification languages, associated tools and increased schedule and budget pressure on projects reduce training opportunities for engineers, and (4) Formulation of correctness properties for system models can be a difficult problem. This has relevance to NASA in that it would simplify development of formal correctness properties, lead to more widespread use of model-based specification, design techniques, assist in earlier identification of defects and reduce residual defect content for space mission software systems. The presentation also discusses: potential applications, accomplishments and/or technological transfer potential and the next steps.

Influence of level and duration of feeding polysaccharide (laminarin and fucoidan) extracts from brown seaweed (Laminaria digitata) on quality indices of fresh pork.

PubMed

Moroney, N C; O'Grady, M N; Robertson, R C; Stanton, C; O'Doherty, J V; Kerry, J P

2015-01-01

The effect of level (450 or 900 mg laminarin (L) and fucoidan (F) /kg feed) and duration (3 or 6 wks) of feeding a seaweed (Laminaria digitata) extract containing L/F on the quality of pork (longissimus thoracis et lumborum (LTL)) stored in modified atmosphere packs and on organ lipid stability was examined. Mechanisms of L/F antioxidant activity in LTL were evaluated. Plasma total antioxidant status, LTL pH, colour, microbiology and 'eating quality' sensory analysis were unaffected by dietary L/F. 'Visual' sensory descriptors (purchasing appeal and overall visual acceptability) were enhanced (p<0.05) in L/F450-3 LTL. Lipid oxidation was lower (p<0.05) in L/F450-3 and L/F900-3 LTL and reduced in L/F900-6 kidney homogenates. In cooked minced pork, lipid oxidation was not reduced by dietary L/F. Saturated fatty acids were lower (p<0.05) in L/F900-6 LTL. Results indicated L/F in pig diets for 3 weeks enhanced pork quality. Copyright © 2014 Elsevier Ltd. All rights reserved.

Zeolite Linde Type L as micro-solid phase extraction sorbent for the high performance liquid chromatography determination of ochratoxin A in coffee and cereal.

PubMed

Lee, Tien Ping; Saad, Bahruddin; Ng, Eng Poh; Salleh, Baharuddin

2012-05-11

Zeolite Linde Type L (LTL) crystals with different length, diameter and particle size (nanosized LTL, rod LTL, cylinder LTL and needle LTL) were synthesized, characterized and were used as sorbent in the micro-solid phase extraction of ochratoxin A (OTA) before the high performance liquid chromatography detection. Under the optimized conditions, the detection limits of OTA for coffee and cereal were 0.09 ng g(-1) and 0.03 ng g(-1), respectively, while the quantification limits were 0.28 ng g(-1) and 0.08 ng g(-1), respectively. The recoveries of OTA of coffee and cereal spiked at 0.5, 10 and 25 ng g(-1) ranged from 91.7 to 101.0%. The proposed method was applied to forty-five samples of coffee and cereal. The presence of OTA was found in twenty-five samples, ranging from 0.28 to 9.33 ng g(-1). Copyright © 2012 Elsevier B.V. All rights reserved.

Leukocyte telomere length and mortality among U.S. adults: Effect modification by physical activity behaviour.

PubMed

Loprinzi, Paul D; Loenneke, Jeremy P

2018-01-01

The purpose of this study was to examine the association between leukocyte telomere length (LTL) and mortality (outcome variable), with consideration by physical activity behaviour. Data from the 1999-2002 National Health and Nutrition Examination Survey were employed (N = 6,611; 20-85 yrs), with follow-up mortality assessment through 31 December 2006. DNA was extracted from whole blood to assess LTL via quantitative polymerase chain reaction. Compared to those in the first LTL tertile, the adjusted hazard ratio for all-cause mortality for those in the 2 nd and 3 rd LTL tertiles, respectively, was 0.82 (95% CI: 0.60-1.12; P = .22) and 0.76 (95% CI: 0.50-1.14; P = .18). However, after adjustments, LTL tertile 3 (vs. 1) was associated with all-cause mortality (HR = 0.37; 95% CI: 0.14-0.93; P = .03) for those who engaged in moderate-intensity exercise. Similarly, LTL was associated with CVD-specific mortality for those who engaged in moderate-intensity exercise (HR = 0.17; 95% CI: 0.04-0.73; P = .02). Longer telomeres are associated with increased survival, particularly among men and those who are active, underscoring the importance of promotion of physical activity behaviour.

Food Security and Leukocyte Telomere Length in Adult Americans.

PubMed

Mazidi, Mohsen; Kengne, Andre Pascal; Vatanparast, Hassan

2017-01-01

Leukocyte telomere length (LTL) is a biomarker of biologic age. Whether food security status modulates LTL is still unknown. We investigated the association between food security and LTL in participants of the 1999-2002 US National Health and Nutrition Examination Survey (NHANES). Analysis of covariance (ANCOVA) was used to evaluate the association between food security categories and LTL controlling for sex, race, and education and accounting for the survey design and sample weights. We included 10,888 participants with 5228 (48.0%) being men. They were aged on average 44.1 years. In all, 2362 (21.7%) had less than high school, 2787 (25.6%) had achieved high school, while 5705 (52.5%) had done more than high school. In sex-, race-, and education-adjusted ANCOVA, average LTL (T/S ratio) for participants with high food security versus those with marginal, low, or very low food security was 1.32 versus 1.20 for the age group 25-35 years and 1.26 versus 1.11 for the 35-45 years, ( p < 0.001). The association between food insecurity and LTL shortening in young adults suggest that some of the future effects of food insecurity on chronic disease risk in this population could be mediated by telomere shortening.

Telomere Length in Epidemiology: A Biomarker of Aging, Age-Related Disease, Both, or Neither?

PubMed Central

Sanders, Jason L.; Newman, Anne B.

2013-01-01

Telomeres are nucleoprotein caps flanking DNA. They are shortened by cell division and oxidative stress and are lengthened by the enzyme telomerase and DNA exchange during mitosis. Short telomeres induce cellular senescence. As an indicator of oxidative stress and senescence (2 processes thought to be fundamental to aging), telomere length is hypothesized to be a biomarker of aging. This hypothesis has been tested for more than a decade with epidemiologic study methods. In cross-sectional studies, researchers have investigated whether leukocyte telomere length (LTL) is associated with demographic, behavioral, and health variables. In prospective studies, baseline LTL has been used to predict mortality and occasionally other adverse health outcomes. Conflicting data have generated heated debate about the value of LTL as a biomarker of overall aging. In this review, we address the epidemiologic data on LTL and demonstrate that shorter LTL is associated with older age, male gender, Caucasian race, and possibly atherosclerosis; associations with other markers of health are equivocal. We discuss the reasons for discrepancy across studies, including a detailed review of methods for measuring telomere length as they apply to epidemiology. Finally, we conclude with questions about LTL as a biomarker of aging and how epidemiology can be used to answer these questions. PMID:23302541

Dysregulated physiological stress systems and accelerated cellular aging.

PubMed

Révész, Dóra; Verhoeven, Josine E; Milaneschi, Yuri; de Geus, Eco J C N; Wolkowitz, Owen M; Penninx, Brenda W J H

2014-06-01

Exposure to chronic stressors is associated with accelerated biological aging as indicated by reduced leukocyte telomere length (LTL). This impact could be because of chronic overactivation of the body's physiological stress systems. This study examined the associations between LTL and the immune system, hypothalamic-pituitary-adrenal axis and autonomic nervous system. LTL was assessed in 2936 adults from the Netherlands Study of Depression and Anxiety. Inflammation markers (interleukin-6, c-reactive protein, tumor necrosis factor-alpha), hypothalamic-pituitary-adrenal-axis indicators (salivary cortisol awakening curve [area under the curve indicators, with respect to the ground and increase], evening levels, 0.5 mg dexamethasone cortisol suppression ratio), and autonomic nervous system measures (heart rate, respiratory sinus arrhythmia, pre-ejection period) were determined. Linear regression analyses were performed and adjusted for sociodemographic, lifestyle and clinical factors. Shorter LTL was significantly associated with higher c-reactive protein, interleukin-6, area under the curve with respect to increase, and heart rate. A cumulative index score was calculated based on the number of highest tertiles of these 4 stress markers. LTL demonstrated a significant gradient within subjects ranging from having zero (5528 base pairs) to having 4 elevated stress markers (5371 base pairs, p for trend = 0.002), corresponding to a difference of 10 years of accelerated biological aging. Contrary to the expectations, shorter LTL was also associated with longer pre-ejection period, indicating lower sympathetic tone. This large-scale study showed that inflammation, high awakening cortisol response, and increased heart rate are associated with shorter LTL, especially when they are dysregulated cumulatively. Copyright © 2014 Elsevier Inc. All rights reserved.

Depressive and Anxiety Disorders Showing Robust, but Non-Dynamic, 6-Year Longitudinal Association With Short Leukocyte Telomere Length.

PubMed

Verhoeven, Josine E; van Oppen, Patricia; Révész, Dóra; Wolkowitz, Owen M; Penninx, Brenda W J H

2016-06-01

Several cross-sectional studies have related depressive and anxiety disorders to shorter leukocyte telomere length (LTL) as an indicator of cellular aging. However, these studies have left many unresolved questions about underlying causality and ordering of associations. The objective of the present large, longitudinal study was to examine the relationship between depressive and anxiety disorders and LTL over a 6-year time period. Data are from the Netherlands Study of Depression and Anxiety, including 2,292 patients with remitted and current diagnoses of depressive or anxiety disorders and 644 healthy control subjects. LTL was assessed using quantitative PCR and measured at baseline and after 6 years; depressive and anxiety disorder diagnoses and characteristics (course, duration, and severity) were determined at baseline and after 2, 4, and 6 years. Results showed that persons with remitted (B=-52.6) and current (B=-60.8) depressive or anxiety disorder had consistently shorter LTL compared with healthy control subjects across baseline and at the 6-year follow-up, remaining significant when controlling for lifestyle and somatic health variables. Changes in the course of depressive or anxiety disorder characteristics over 6 years, however, were not associated with different LTL attrition rates. This study confirmed robust associations of depressive and anxiety disorders with shorter telomeres, but interestingly, it did not demonstrate that depressive and anxiety disorders and LTL change together over time, suggesting the absence of a direct within-person relationship. Short LTL is suggested to be either a long-term consequence or an underlying vulnerability factor for depressive or anxiety disorders.

Epidemiological and Mendelian Randomization Studies of Dihydrotestosterone and Estradiol and Leukocyte Telomere Length in Men.

PubMed

Yeap, Bu B; Knuiman, Matthew W; Divitini, Mark L; Hui, Jennie; Arscott, Gillian M; Handelsman, David J; McLennan, Susan V; Twigg, Stephen M; McQuillan, Brendan; Hung, Joseph; Beilby, John P

2016-03-01

Advancing age is accompanied by an accumulation of ill health and shortening of chromosomal telomeres signifying biological aging. T is metabolized to DHT by 5α-reductase (SRD5A2) and to estradiol (E2) by aromatase (CYP19A1). Telomerase preserves telomeres, and T and E2 regulate telomerase expression and activity in vitro. The objective of the study was to establish whether circulating T or its metabolites, DHT or E2, and single-nucleotide polymorphisms in SRD5A2 or CYP19A1 associate with leucocyte telomere length (LTL) in men. Early-morning serum T, DHT, and E2 were assayed using mass spectrometry, and SRD5A2 and CYP19A1 single-nucleotide polymorphisms and LTL analyzed by PCR in 980 men from the Western Australian Busselton Health Survey who participated in the study. LTL was expressed as the T/S ratio. Men were aged (mean ± SD) 53.7 ± 15.6 years. LTL decreased linearly with age, from the T/S ratio of 1.89 ± 0.41 at younger than 30 years to 1.50 ± 0.49 at 70 to younger than 80 years (r = -0.225, P < .0001). After adjustment for age, DHT and E2 were positively correlated with LTL (DHT, r = 0.069, P = .030; E2, r = 0.068, P = .034). The SRD5A2 rs9282858 polymorphism was associated with serum DHT but not with LTL. Three dominant alleles of CYP19A1 were each associated with lower serum E2 and shorter LTL: rs2899470 T (E2, 59.3 vs 68.6 pmol/L, P < .0001; T/S ratio, 1.54 vs 1.62, P = .045), rs10046 C (60.5 vs 68.1 pmol/L, P = .0005, 1.54 vs 1.62, P = .035), and rs700518 A (59.9 vs 68.9 pmol/L, P < .0001, 1.54 vs 1.63, P = .020). A single-copy haplotype C/T/I/A/T rs10046/rs2899470/rs11575899/rs700518/rs17703883 (52% prevalence) was associated with both lower E2 and shorter LTL. In men, serum DHT and E2 correlate with LTL independently of age. Aromatase gene polymorphisms include three dominant alleles that are associated with both lower serum E2 and shorter LTL. E2 influences telomere length in vivo, thus warranting further studies to examine whether hormonal interventions might slow biological aging in men.

Subrenal capsule grafting technology in human cancer modeling and translational cancer research.

PubMed

Wang, Yuzhuo; Wang, Joy X; Xue, Hui; Lin, Dong; Dong, Xin; Gout, Peter W; Gao, Xin; Pang, Jun

2016-01-01

Patient-derived xenograft (PDX) cancer models with high fidelity are in great demand. While the majority of PDXs are grafted under the skin of immunodeficient mice, the Living Tumor Laboratory (LTL), using unique subrenal capsule grafting techniques, has successfully established more than 200 transplantable PDX models of various low to high grade human cancers. The LTL PDX models retain key biological properties of the original malignancies, including histopathological and molecular characteristics, tumor heterogeneity, metastatic ability, and response to treatment. The PDXs are stored frozen at early transplant generations in a resurrectable form, which eliminates continuous passaging in mice, thus ensuring maintenance of the high biologic and molecular fidelity and reproducibility of the models. The PDX models have been demonstrated to be powerful tools for (i) studies of cancer progression, metastasis and drug resistance, (ii) evidenced-based precision cancer therapy, (iii) preclinical drug efficacy testing and discovery of new anti-cancer drug candidates. To better provide resources for the research community, an LTL website (www.livingtumorlab.com) has been designed as a publicly accessible database which allows researchers to identify PDX models suitable for translational/preclinical cancer research. In summary, subrenal capsule grafting technology maximizes both tumor engraftment rate and retention of human cancer heterogeneity. Moreover, the method makes possible the recovery of PDXs from frozen stocks for further applications, thus providing a powerful platform for translational cancer research. Copyright © 2015 International Society of Differentiation. Published by Elsevier B.V. All rights reserved.

Association of telomere length with type 2 diabetes, oxidative stress and UCP2 gene variation.

PubMed

Salpea, Klelia D; Talmud, Philippa J; Cooper, Jackie A; Maubaret, Cecilia G; Stephens, Jeffrey W; Abelak, Kavin; Humphries, Steve E

2010-03-01

High oxidative stress potentially leads to accelerated telomere shortening and consequent premature cell senescence, implicated in type 2 diabetes (T2D) development. Therefore, we studied the association of leukocyte telomere length (LTL) with the presence of T2D, as well as the effect on the patients' LTL of plasma oxidative stress and of variation in UCP2, a gene involved in the mitochondrial production of reactive oxygen species. Mean LTL was determined in 569 Caucasian, 103 South Asian and 70 Afro-Caribbean T2D patients aged from 24 to 92 years, 81 healthy Caucasian male students aged from 18 to 28 years and 367 healthy Caucasian men aged from 40 to 61 years by real-time PCR. Plasma total antioxidant status (TAOS) was measured in the T2D patients by a photometric microassay. The patients were also genotyped for the UCP2 functional variants -866G>A and A55V. Afro-Carribeans had 510bp longer mean length compared to Caucasians (p<0.0001) and 500bp longer than South Asians (p=0.004). T2D subjects displayed shorter age-adjusted LTL compared to controls [6.94(6.8-7.03) vs. 7.72(7.53-7.9), p<0.001] with subjects in the middle and the lowest tertile of LTL having significantly higher odds ratios for T2D compared to those in the highest tertile [1.50(1.08-2.07) and 5.04(3.63-6.99), respectively, p<0.0001]. In the patients, LTL was correlated negatively with age (r=-0.18, p<0.0001) and positively with TAOS measures (r=0.12, p=0.01) after adjusting for age, while carriers of the UCP2 -866A allele had shorter age-adjusted LTL than common homozygotes [6.86(6.76-6.96)kb vs. 7.03(6.91-7.15)kb, p=0.04]. The present data suggest that shorter LTL is associated with the presence of T2D and this could be partially attributed to the high oxidative stress in these patients. The association of the UCP2 functional promoter variant with the LTL implies a link between mitochondrial production of reactive oxygen species and shorter telomere length in T2D.

Leukocyte telomere length and personality: associations with the Big Five and Type D personality traits.

PubMed

Schoormans, D; Verhoeven, J E; Denollet, J; van de Poll-Franse, L; Penninx, B W J H

2018-04-01

Backgrounds Accelerated cellular ageing, which can be examined by telomere length (TL), may be an overarching mechanism underlying the association between personality and adverse health outcomes. This 6-year longitudinal study examined the relation between personality and leukocyte telomere length (LTL) across time among adults with a wide age-range. Data from the Netherlands Study of Depression and Anxiety were used and included patients with a depression and/or anxiety disorder and healthy controls. Overall, 2936 persons (18-65 years, 66% female) had data on LTL at baseline and 1883 persons had LTL at 6-year follow-up. The Big Five personality traits (neuroticism, extraversion, openness to experience, agreeableness, and conscientiousness) and Type D personality were assessed. Neuroticism was negatively (B = -2.11, p = 0.03) and agreeableness was positively (B = 3.84, p = 0.03) related to LTL measured across two time points, which became just non-significant after adjusting for somatic health, lifestyle factors, and recent life stress (B = -1.99, p = 0.06; and B = 3.01, p = 0.10). Type D personality was negatively (B = -50.16, p < 0.01) related to LTL across two time points, which still remained statistically significant after full adjustment (B = -47.37, p = 0.01). Associations did not differ by age, gender, and current psychiatric status. The Big Five traits high neuroticism and low agreeableness, and Type D personality were associated with shorter LTL measured across a 6-year period. Associations with the Big Five traits became non-significant after controlling for somatic health, lifestyle factors, and recent life stress, yet similar trends were observed. Type D personality remained independently associated with shorter LTL after full adjustment.

Reconfirmation of the anatomy of the left triangular ligament and the appendix fibrosa hepatis in human livers, and its implication in abdominal surgery.

PubMed

Kogure, Kimitaka; Kojima, Itaru; Kuwano, Hiroyuki; Matsuzaki, Toshiyuki; Yorifuji, Hiroshi; Takata, Kuniaki; Makuuchi, Masatoshi

2014-12-01

The aim of the present study was to clarify the anatomy between the left triangular ligament (LTL) and the appendix fibrosa hepatis (AFH) in order not to sever the AFH when dissecting the LTL. Totals of 43 and 27 cadaveric livers were examined macroscopically and histologically, respectively. The LTL attached itself to the diaphragmatic surface of the AFH through almost all lengths of the AFH. This might be the reason why AFH is so often dissected together with the LTL. There were two types of relation between the LTL and the AFH; in one type, the starting point of the LTL existed on the left liver and in the other type, it was on the AFH. Twenty-five of 27 AFH included remnants of the bile duct and 12 of 25 AFH had comparatively large bile ducts, which was unexceptionally accompanied by the well-developed peribiliary vascular plexus. AFH showed a variety of shapes, such as rectangular (6/43), long triangular (4/43), short triangular (7/43), triangular plus cordlike (11/43), cordlike (12/43) and bifurcated (3/43) types. As AFH sometimes includes relatively large bile ducts, it is recommended for surgeons to sever the AFH not just simply by electrocautery but by ligating its stump securely. © 2014 Japanese Society of Hepato-Biliary-Pancreatic Surgery.

Linear Temporal Logic (LTL) Based Monitoring of Smart Manufacturing Systems

PubMed Central

Heddy, Gerald; Huzaifa, Umer; Beling, Peter; Haimes, Yacov; Marvel, Jeremy; Weiss, Brian; LaViers, Amy

2017-01-01

The vision of Smart Manufacturing Systems (SMS) includes collaborative robots that can adapt to a range of scenarios. This vision requires a classification of multiple system behaviors, or sequences of movement, that can achieve the same high-level tasks. Likewise, this vision presents unique challenges regarding the management of environmental variables in concert with discrete, logic-based programming. Overcoming these challenges requires targeted performance and health monitoring of both the logical controller and the physical components of the robotic system. Prognostics and health management (PHM) defines a field of techniques and methods that enable condition-monitoring, diagnostics, and prognostics of physical elements, functional processes, overall systems, etc. PHM is warranted in this effort given that the controller is vulnerable to program changes, which propagate in unexpected ways, logical runtime exceptions, sensor failure, and even bit rot. The physical component’s health is affected by the wear and tear experienced by machines constantly in motion. The controller’s source of faults is inherently discrete, while the latter occurs in a manner that builds up continuously over time. Such a disconnect poses unique challenges for PHM. This paper presents a robotic monitoring system that captures and resolves this disconnect. This effort leverages supervisory robotic control and model checking with linear temporal logic (LTL), presenting them as a novel monitoring system for PHM. This methodology has been demonstrated in a MATLAB-based simulator for an industry inspired use-case in the context of PHM. Future work will use the methodology to develop adaptive, intelligent control strategies to evenly distribute wear on the joints of the robotic arms, maximizing the life of the system. PMID:28730154

Evaluation of retroreflectometers.

DOT National Transportation Integrated Search

2002-08-01

This project performed field-testing and analysis of two pavement marking retroreflectometers: the Laserlux and the : LTL2000. The Laserlux is a vehiclemounted device that takes readings at driving speed and produces : computerized output. The LTL...

Influence of diet on leukocyte telomere length, markers of inflammation and oxidative stress in individuals with varied glucose tolerance: a Chinese population study.

PubMed

Zhou, Meicen; Zhu, Lixin; Cui, Xiangli; Feng, Linbo; Zhao, Xuefeng; He, Shuli; Ping, Fan; Li, Wei; Li, Yuxiu

2016-04-12

To explore influence of carbohydrates/fat proportions, dietary ingredients on telomere length shortening, oxidative stress and inflammation in a Chinese population with different glucose tolerance status. Five hundred and fifty-six Chinese subjects without diabetes history underwent a 75 g, 2 h Oral Glucose Tolerance Test (OGTT). Subjects with diabetes (n = 159), pre-diabetes (n = 197), and normal glucose tolerance (n = 200) were screened. Dietary intakes were evaluated using a semi-quantitative food frequency questionnaire (FFQ). Peripheral blood leukocyte telomere length (LTL) was assessed using a real-time PCR assay. Blood lipid profile, levels of the oxidative stress indicators superoxide dismutase (SOD), glutathione reductase (GR), 8-oxo-2'-deoxyguanosine (8-oxo-dG) and inflammation indicators tumor necrosis factor (TNF-ɑ), interleukine-6 (IL-6) were measured. Levels of HbA1c, plasma glucose, insulin, and C peptide were also determined. Measurements were taken at 0 min, 30 min, 60 min, and 120 min after 75 g OGTT. Insulin sensitivity was evaluated by HOMA-IR. Basal insulin secretion index (HOMA-β), early phase disposition index (DI30) and total phase disposition index (DI120) indicate insulin levels at different phases of insulin secretion. In patients with newly diagnosed diabetes, LTL adjusted by age was longer in HbA1c < 7 % group (log (LTL):1.93 ± 0.25) than in HbA1c ≥ 7 % group (log (LTL):1.82 ± 0.29). LTL was not associated with daily energy intake, diet fat, carbohydrates and protein proportions. Multiple linear regression analysis indicated that legumes, nuts, fish and seaweeds were protective factors for LTL shortening, and sweetened carbonated beverage was a risk factor for LTL shortening ( legumes: β = 0.105, p = 0.018; nuts: β = 0.110, p = 0.011; fish: β = 0.118, p = 0.007; seaweeds: β = 0.116, p = 0.009; sweetened carbonated beverage: β = -0.120, p = 0.004 ). Daily energy intake was positively associated with TNF-ɑ, IL-6 (TNF-ɑ: r = 0.125, p = 0.006;IL-6: r = 0.092, p =0.04). Fat, carbohydrate proportions were positively associated with TNF-ɑ (fat: r = 0.119, p = 0.008 ; carbohydrate: r = 0.094, p = 0.043). Seaweeds and dairy intake were negatively associated with 8-oxo-dG (seaweed: r = -0.496, p = 0.001;dairy: r = -0.246, p = 0.046 ), vegetables and fruits were positively associated with GR ( vegetables: r = 0.101, p = 0.034;fruits: r = 0.125, p = 0.045). Cereal, meat were positively associated with TNF-ɑ ( cereal: r = 0.091, p = 0.048 ; meat: r = 0.405, p = 0.009). Diabetes patients with better plasma glucose (HbA1c < 7 %) had longer LTL, LTL could reflect plasma glucose status in diabetes patients. LTL were probably not influenced by diet carbohydrates/fat proportions but was associated with diet ingredients. Diet ingredients significantly impacted on markers of inflammation and oxidative stress, which probably had an effect on LTL.

Relationship between plasma 25-hydroxymitamin D and leucocyte telomere length by sex and race in a US study.

PubMed

Liu, Jason J; Cahoon, Elizabeth K; Linet, Martha S; Little, Mark P; Dagnall, Casey L; Higson, Herbert; Savage, Sharon A; Freedman, D Michal

2016-09-01

A few studies have examined the association between vitamin D and telomere length, and fewer still have examined the relationship in black or male populations. We investigated the cross-sectional association between the vitamin D metabolite 25-hydroxyvitamin D (25(OH)D) concentration in plasma and relative leucocyte telomere length (LTL) in 1154 US radiologic technologists who were 48-93 years old (373 white females, 278 white males, 338 black females, 165 black males). Plasma 25(OH)D concentration was measured by the chemiluminescence immunoassay, and relative LTL was measured by quantitative PCR. Logistic regression was used to obtain OR and 95 % CI for long v. short (based on median) LTL in relation to continuous 25(OH)D, quartiles of 25(OH)D and 25(OH)D deficiency. We found no significant association between continuous 25(OH)D and long LTL in all participants (P trend=0·440), nor in white females (P trend=0·845), white males (P trend=0·636), black females (P trend=0·967) or black males (P trend=0·484). Vitamin D deficiency (defined as 25(OH)D<30 nmol/l), however, was significantly associated with short LTL in whites (P=0·024), but not in other groups. In this population, we found little evidence to support associations between 25(OH)D and long LTL over the entire range of 25(OH)D in the overall study population or by sex and race.

Low estrogen levels and obesity are associated with shorter telomere lengths in pre- and postmenopausal women.

PubMed

Shin, Yun-A; Lee, Kyoung-Young

2016-06-01

The aim of this study was to determine whether there is an association between leukocyte telomere length (LTL), and estrogen level, oxidative stress, cardiovascular disease (CVD) risk factors, and cardiorespiratory fitness (CRF) in pre- and postmenopausal obese women. Fifty-four obese women (premenopausal, n=25; postmenopausal, n=29) were selected to participate in this study. The outcome measurements in the pre- and postmenopausal groups were compared using independent t-tests and Pearson correlation analysis. The estrogen level (P<0.001), LTL (P<0.05), high-density lipoprotein level (P<0.05), and CRF (P<0.001) were higher in premenopausal women than in postmenopausal women. The body fat percentage (P<0.05) and triglyceride concentration (P<0.05) were lower in premenopausal women than in postmenopausal women. There were no significant associations between LTL, CVD risk, CRF, and oxidative stress and antioxidant enzyme activity in pre-menopausal women. The body mass index (BMI) and body fat percent-age in postmenopausal women were negatively associated with LTL (P<0.05). When all women were considered (i.e., both pre- and post-menopause), the BMI, percentage of fat, and waist circumference had a negative association with LTL (P<0.05), and estrogen levels were positively associated with LTL (P<0.05). Decreased estrogen levels after menopause, a pivotal factor in the biology of aging, and obesity were more associated with shorter telomere lengths in pre- and postmenopausal women than aerobic capacity and other CVD risk factors.

Accumulative effects of indoor air pollution exposure on leukocyte telomere length among non-smokers.

PubMed

Lin, Nan; Mu, Xinlin; Wang, Guilian; Ren, Yu'ang; Su, Shu; Li, Zhiwen; Wang, Bin; Tao, Shu

2017-08-01

Indoor air pollution is an important environmental factor that contributes to the burden of various diseases. Long-term exposure to ambient air pollution is associated with telomere shortening. However, the association between chronic indoor air pollution from household fuel combustion and leukocyte telomere length has not been studied. In our study, 137 cancer-free non-smokers were recruited. Their exposure levels to indoor air pollution from 1985 to 2014 were assessed using a face-to-face interview questionnaire, and leukocyte telomere length (LTL) was measured using a monochrome multiplex quantitative PCR method. Accumulative exposure to solid fuel usage for cooking was negatively correlated with LTL. The LTL of residents who were exposed to solid fuel combustion for three decades (LTL = 0.70 ± 0.17) was significantly shorter than that of other populations. In addition, education and occupation were related to both exposure to solid fuel and LTL. Sociodemographic factors may play a mediating role in the correlation between leukocyte telomere length and environmental exposure to indoor air pollution. In conclusion, long-term exposure to indoor air pollution may cause LTL dysfunction. Copyright © 2017 Elsevier Ltd. All rights reserved.

Effects of cigarette smoking and nicotine metabolite ratio on leukocyte telomere length.

PubMed

Verde, Zoraida; Reinoso-Barbero, Luis; Chicharro, Luis; Garatachea, Nuria; Resano, Pilar; Sánchez-Hernández, Ignacio; Rodríguez González-Moro, Jose Miguel; Bandrés, Fernando; Santiago, Catalina; Gómez-Gallego, Félix

2015-07-01

Studies of the effects of smoking on leukocyte telomere length (LTL) using cigarettes smoked per day or pack years smoked (PYS) present limitations. Reported high levels of smoking may not increase toxin exposure levels proportionally. Nicotine metabolism ratio (NMR) predicts total cigarette puff volume and overall exposure based on total N-nitrosamines, is highly reproducible and independent of time since the last cigarette. We hypothesized that smokers with higher NMRs will exhibit increased total puff volume, reflecting efforts to extract more nicotine from their cigarettes and increasing toxin exposure. In addition, higher levels of smoking could cause a gross damage in LTL. The urinary cotinine, 3-OH cotinine and nicotine levels of 147 smokers were analyzed using a LC/MS system Triple-Q6410. LTL and CYP2A6 genotype was determined by PCR in blood samples. We found a significant association between NMR and CYP2A6 genotype. Reduction in LTL was seen in relation to accumulated tobacco consumption and years smoking when we adjusted for age and gender. However, there were no significant differences between NMR values and LTL. In our study the higher exposure was associated with lower number of PYS. Smokers with reduced cigarette consumption may exhibit compensatory smoking behavior that results in no reduced tobacco toxin exposure. Our results suggest that lifetime accumulated smoking exposure could cause a gross damage in LTL rather than NMR or PYS. Nevertheless, a combination of smoking topography (NMR) and consumption (PYS) measures may provide useful information about smoking effects on health outcomes. Copyright © 2015 Elsevier Inc. All rights reserved.

PSYCHIATRIC DISORDERS AND LEUKOCYTE TELOMERE LENGTH: UNDERLYING MECHANISMS LINKING MENTAL ILLNESS WITH CELLULAR AGING

PubMed Central

Lindqvist, Daniel; Epel, Elissa S.; Mellon, Synthia H.; Penninx, Brenda W.; Révész, Dóra; Verhoeven, Josine E.; Reus, Victor I.; Lin, Jue; Mahan, Laura; Hough, Christina M.; Rosser, Rebecca; Bersani, F. Saverio; Blackburn, Elizabeth H.; Wolkowitz, Owen M.

2015-01-01

Many psychiatric illnesses are associated with early mortality and with an increased risk of developing physical diseases that are more typically seen in the elderly. Moreover, certain psychiatric illnesses may be associated with accelerated cellular aging, evidenced by shortened leukocyte telomere length (LTL), which could underlie this association. Shortened LTL reflects a cell’s mitotic history and cumulative exposure to inflammation and oxidation as well as the availability of telomerase, a telomere-lengthening enzyme. Critically short telomeres can cause cells to undergo senescence, apoptosis or genomic instability, and shorter LTL correlates with poorer health and predicts mortality. Emerging data suggest that LTL may be reduced in certain psychiatric illnesses, perhaps in proportion to exposure to the psychiatric illnesses, although conflicting data exist. Telomerase has been less well characterized in psychiatric illnesses, but a role in depression and in antidepressant and neurotrophic effects has been suggested by preclinical and clinical studies. In this article, studies on LTL and telomerase activity in psychiatric illnesses are critically reviewed, potential mediators are discussed, and future directions are suggested. A deeper understanding of cellular aging in psychiatric illnesses could lead to re-conceptualizing them as systemic illnesses with manifestations inside and outside the brain and could identify new treatment targets. PMID:25999120

Telomere length and telomerase in a well-characterized sample of individuals with major depressive disorder compared to controls.

PubMed

Simon, Naomi M; Walton, Zandra E; Bui, Eric; Prescott, Jennifer; Hoge, Elizabeth; Keshaviah, Aparna; Schwarz, Noah; Dryman, Taylor; Ojserkis, Rebecca A; Kovachy, Benjamin; Mischoulon, David; Worthington, John; De Vivo, Immaculata; Fava, Maurizio; Wong, Kwok-Kin

2015-08-01

Leukocyte telomere length (LTL) is a marker of cellular turnover and oxidative stress. Studies suggest major depressive disorder (MDD) is associated with oxidative stress, but examinations of MDD and LTL have yielded mixed results, likely because of differences in measurement methods and unmeasured confounding. This study examined LTL and telomerase activity in 166 individuals with MDD compared to 166 age- and gender-matched matched controls free of any psychiatric disorder, using well-validated assays and clinical assessment methods, and controlling for a range of potential confounders. Subjects aged 18 to 70 were evaluated by trained raters and provided blood for LTL and telomerase activity measurement. LTL was assayed using Southern blot and replicated with qPCR, and telomerase activity was assayed with a repeat amplification protocol using a commercial kit. There was no significant difference in telomere length for individuals with MDD [mean (SD)=9.1 (3.0)kbp] compared to controls [mean(SD)=8.9(2.5)kbp] measured by Southern blot (p=0.65) or by confirmatory qPCR (p=0.91) assays. Controlling for potential confounders did not alter the results. Telomerase activity did not differ by MDD diagnosis overall (p=0.40), but the effect of MDD was significantly modified by gender (t(299)=2.67, p=0.0079) even after controlling for potential confounders, with telomerase activity significantly greater only in males with MDD versus controls. Our well-characterized, well-powered examination of concurrently assessed telomere length and telomerase activity in individuals with clinically significant, chronic MDD and matched controls failed to provide strong evidence of an association of MDD with shorter LTL, while telomerase activity was higher in men with MDD [corrected]. Copyright © 2015 Elsevier Ltd. All rights reserved.

Muscle-specific colour stability of blesbok (Damaliscus pygargus phillipsi) meat.

PubMed

Neethling, Nikki E; Suman, Surendranath P; Sigge, Gunnar O; Hoffman, Louwrens C

2016-09-01

The increasing demand for meat from alternative species, such as blesbok (Damaliscus pygargus phillipsi), gives rise to the need for characterizing the quality attributes of fresh meat from these species. While muscle-specific colour stability has been extensively studied in conventional livestock, limited information is available on this phenomenon in game meat. Therefore, the objective of this study was to examine the colour stability of three major blesbok muscles, infraspinatus (IS), longissimus thoracis et lumborum (LTL) and biceps femoris (BF). Instrumental colour, surface myoglobin redox forms, and biochemical attributes influencing colour stability were measured on 2.5-cm steaks from blesbok IS, LTL, and BF during refrigerated storage under aerobic conditions for eight days. IS steaks consistently demonstrated higher (P≤0.05) redness, colour stability, and chroma than the LTL and BF steaks. These findings suggested that blesbok IS muscle is more colour-stable than its LTL and BF counterparts. The game industry may employ muscle-specific strategies to improve marketability of fresh blesbok meat. Copyright © 2016 Elsevier Ltd. All rights reserved.

Development of Learning to Learn Skills in Primary School

ERIC Educational Resources Information Center

Vainikainen, Mari-Pauliina; Wüstenberg, Sascha; Kupiainen, Sirkku; Hotulainen, Risto; Hautamäki, Jarkko

2015-01-01

In Finland, schools' effectiveness in fostering the development of transversal skills is evaluated through large-scale learning to learn (LTL) assessments. This article presents how LTL skills--general cognitive competences and learning-related motivational beliefs--develop during primary school and how they predict pupils' CPS skills at the end…

Paternal age at birth is associated with offspring leukocyte telomere length in the nurses' health study.

PubMed

Prescott, J; Du, M; Wong, J Y Y; Han, J; De Vivo, I

2012-12-01

Is the association between paternal age at birth and offspring leukocyte telomere length (LTL) an artifact of early life socioeconomic status (SES)? Indicators of early life SES did not alter the relationship between paternal age at birth and offspring LTL among a population of white female nurses. Telomere length is considered a highly heritable trait. Recent studies report a positive correlation between paternal age at birth and offspring LTL. Maternal age at birth has also been positively associated with offspring LTL, but may stem from the strong correlation with paternal age at birth. The Nurses' Health Study (NHS) is an ongoing prospective cohort study of 121 700 female registered nurses who were enrolled in 1976. Great effort goes into maintaining a high degree of follow-up among our cohort participants (>95% of potential person-years). In 1989-1990, a subset of 32 826 women provided blood samples from which we selected participants for several nested case-control studies of telomere length and incident chronic disease. We used existing LTL data on a total of 4250 disease-free women who also reported maternal and paternal age at birth for this study. Nested case-control studies of stroke, myocardial infarction, cancers of the breast, endometrium, skin, pancreas and colon, as well as colon adenoma, were conducted within the blood sub-cohort. Each study used the following study design: for each case of a disease diagnosed after blood collection, a risk-set sampling scheme was used to select from one to three controls from the remaining participants in the blood sub-cohort who were free of that disease when the case was diagnosed. Controls were matched to cases by age at blood collection (± 1 year), date of blood collection (± 3 months), menopausal status, recent postmenopausal hormone use at blood collection (within 3 months, except for the myocardial infarction case-control study), as well as other factors carefully chosen for each individual study. The current analysis was limited to healthy controls. We also included existing LTL data from a small random sample of women participating in a cognitive sub-study. LTL was measured using the quantitative PCR-based method. Exposure and covariate information are extracted from biennial questionnaires completed by the participants. We found a strong association between paternal age at birth and participant LTL (P = 1.6 × 10(-5)) that remained robust after controlling for indicators of early life SES. Maternal age at birth showed a weak inverse association with participant LTL after adjusting for age at blood collection and paternal age at birth (P = 0.01). We also noted a stronger association between paternal age at birth and participant LTL among premenopausal than among postmenopausal women (P(interaction) = 0.045). However, this observation may be due to chance as premenopausal women represented only 12.6% (N = 535) of the study population and LTL was not correlated with age at menopause, total or estrogen-only hormone therapy (HT) use suggesting that changes in in vivo estrogen exposure do not influence telomere length regulation. The women in our study are not representative of the general US female population, with an underrepresentation of non-white and low social class groups. Although the interaction was not significant, we noted that the paternal age at birth association with offspring LTL appeared weaker among women whose parents did not own their home at the time of the participant's birth. As telomere dynamics may differ among individuals who are most socioeconomically deprived, SES indicators may have more of an influence on the relationship between paternal age at birth and offspring LTL in such populations. As of yet, our and prior studies have not identified childhood or adult characteristics that confound the paternal age at birth association with offspring LTL, supporting the hypothesis that offspring may inherit the longer telomeres found in sperm of older men. The biological implications of the paternal age effect are unknown. A recent theory proposed that the inheritance of longer telomere from older men may be an adaptive signal of reproductive lifespan, while another theory links telomere length attrition to female reproductive senescence. However, we are unaware of any data to substantiate a relationship between paternal age at birth and daughter's fertility. Generalizability of our study results to other white female populations is supported by prior reports of paternal age at birth and offspring telomere length. Furthermore, a confounding relationship between paternal or maternal age at birth and SES was not observed in a study of SES and telomere length. This work was supported by the National Institutes of Health (grants numbers: CA87969, CA49449, CA065725, CA132190, CA139586, HL088521, CA140790, CA133914, CA132175, ES01664 to M.D.); and by the American Health Association Foundation. We have no competing interests to declare.

Distribution of inorganic species in two Antarctic cryptoendolithic microbial communities

NASA Technical Reports Server (NTRS)

Johnston, C. G.; Vestal, J. R.; Friedmann, E. I. (Principal Investigator)

1989-01-01

Chemical differences were noted between two Antarctic cryptoendolithic (hidden within rock) microenvironments colonized by different microbial communities. Microenvironments dominated by cyanobacteria (BPC) had a higher pH (pH 7-8) than those dominated by lichen (LTL) (pH 4.5-5.5). In order to understand the interactions between the microbiota and the inorganic environment, the inorganic environment was characterized. Water-soluble, carbonate-bound, metal-oxide, organically bound, and residual inorganic species were sequentially extracted from rock samples by chemical means. Each fraction was then quantified using inductively coupled plasma atomic emission spectrometry. BPC contained much more water-soluble and carbonate-bound Ca and Mg than LTL. Metal-oxide species of Al, Fe, and Mn were more abundant in LTL than BPC. Metal oxides appeared to be mobilized (in the order Mn > Fe > Al) from the LTL lichen zone but remained immobile in BPC sandstone. The distribution of K and P bound to metal oxide reflected the distribution of iron oxide in LTL, an indication of the importance of iron in controlling the availability of nutrients in this ecosystem. Metal oxides in turn were likely controlled or influenced by organic matter associated with the lichen community. Despite overall depletion of Fe, Al, and K in the lichen zone, SEM X-ray analysis showed that they were enriched in fungal hyphae. Water-soluble P was present despite the presence of metal oxides, which sequester phosphate. This has biological relevance since P is an essential nutrient.

Telomerase RNA Component (TERC) genetic variants interact with the mediterranean diet modifying the inflammatory status and its relationship with aging: CORDIOPREV study

USDA-ARS?s Scientific Manuscript database

Background: Leukocyte telomere length (LTL) attrition has been associated with age-related diseases. Telomerase RNA Component (TERC) genetic variants have been associated with LTL; whereas fatty acids (FAs) can interact with genetic factors and influence in aging. We explore whether variability at t...

U.S. EPA, Pesticide Product Label, CSA DOG AND CAT REPELLENT AEROSOL SPRAY, 03/31/1993

EPA Pesticide Factsheets

2011-04-14

... II il I ,illi.1 .1 re'er.1 II. I. lie Itil ,IO'act il • 111~el i.-.lliliell .itt ita I.telill. ~ rr .. ... latri'l .r ,llIliti. lelt Itt elletl .1 I.is ,r.'ltl t, lirll Ire.lil, • 11111 htlll,ltlOll Iftl. ...

Telomeric repeat-containing RNA (TERRA) related to polycystic ovary syndrome (PCOS).

PubMed

Wang, Caiqin; Shen, Fengxian; Zhu, Yuning; Fang, Yuying; Lu, Shiming

2017-04-01

Telomeric repeat-containing RNA (TERRA) participates in the regulation of telomere length, and leucocyte telomere length (LTL) plays an important role in the pathophysiology of polycystic ovary syndrome (PCOS), but little is known about the role of TERRA in PCOS. To evaluate the role of TERRA and peripheral blood LTL in PCOS. Forty women with PCOS and 35 healthy women without PCOS were recruited. A prospective case-control study was performed. RNA fluorescence in situ hybridization (FISH) was used to detect TERRA expression in peripheral blood leucocyte. Quantitative PCR was used to measure TERRA expression and the mean LTL in the PCOS and control groups. We analysed the association between related clinical parameters and the age-adjusted ratio of the telomere repeat length (T/S ratio) or TERRA. Telomeric repeat-containing RNA was expressed in human peripheral blood leucocytes, and the signal was abolished after culture with RNase A. The age-adjusted LTLs were significantly longer in the PCOS group than in the control group (P < 0·01). The age-adjusted TERRA level was significantly lower in the PCOS group than in the control group (P < 0·01). Testosterone (TTE) was related positively to LTL and negatively to TERRA in the PCOS group (r = 0·532, P = 0·002; r = -0·477, P = 0·017). We found TERRA expression in human peripheral blood leucocytes, and LTLs were positively associated with PCOS. TERRA and testosterone play an important role in the LTL regulation in PCOS. © 2016 John Wiley & Sons Ltd.

Population-specific association of genes for telomere-associated proteins with longevity in an Italian population.

PubMed

Crocco, Paolina; Barale, Roberto; Rose, Giuseppina; Rizzato, Cosmeri; Santoro, Aurelia; De Rango, Francesco; Carrai, Maura; Fogar, Paola; Monti, Daniela; Biondi, Fiammetta; Bucci, Laura; Ostan, Rita; Tallaro, Federica; Montesanto, Alberto; Zambon, Carlo-Federico; Franceschi, Claudio; Canzian, Federico; Passarino, Giuseppe; Campa, Daniele

2015-06-01

Leukocyte telomere length (LTL) has been observed to be hereditable and correlated with longevity. However, contrasting results have been reported in different populations on the value of LTL heritability and on how biology of telomeres influences longevity. We investigated whether the variability of genes correlated to telomere maintenance is associated with telomere length and affects longevity in a population from Southern Italy (20-106 years). For this purpose we analyzed thirty-one polymorphisms in eight telomerase-associated genes of which twelve in the genes coding for the core enzyme (TERT and TERC) and the remaining in genes coding for components of the telomerase complex (TERF1, TERF2, TERF2IP, TNKS, TNKS2 and TEP1). We did not observe (after correcting for multiple testing) statistically significant associations between SNPs and LTL, possibly suggesting a low genetic influence of the variability of these genes on LTL in the elderly. On the other hand, we found that the variability of genes encoding for TERF1 and TNKS2, not directly involved in LTL, but important for keeping the integrity of the structure, shows a significant association with longevity. This suggests that the maintenance of these chromosomal structures may be critically important for preventing, or delaying, senescence and aging. Such a correlation was not observed in a population from northern Italy that we used as an independent replication set. This discrepancy is in line with previous reports regarding both the population specificity of results on telomere biology and the differences of aging in northern and southern Italy.

Lightening the Load

DTIC Science & Technology

2007-09-09

Research, Engineering and Systems) Dr. John C. Sommerer NRAC, Vice Chair; Director, S&T, Johns Hopkins Applied Physics Laboratory Dr. Walt...O’Donohue, Staff Officer General Dynamics Robotic Systems John H. Northrop & Associates Mr. John H. Northrop, Executive Director General Dynamics...Equipment, US Army LtCol John Lemondes, PM Soldier as a System LTL Efforts US Army Mr. Bob Conklin, Staff UK LTL Efforts Equipment Capability

Socioeconomic Status, Financial Strain, and Leukocyte Telomere Length in a Sample of African American Midlife Men.

PubMed

Schrock, Joshua M; Adler, Nancy E; Epel, Elissa S; Nuru-Jeter, Amani M; Lin, Jue; Blackburn, Elizabeth H; Taylor, Robert Joseph; Chae, David H

2018-06-01

African American men in the USA experience poorer aging-related health outcomes compared to their White counterparts, partially due to socioeconomic disparities along racial lines. Greater exposure to socioeconomic strains among African American men may adversely impact health and aging at the cellular level, as indexed by shorter leukocyte telomere length (LTL). This study examined associations between socioeconomic factors and LTL among African American men in midlife, a life course stage when heterogeneity in both health and socioeconomic status are particularly pronounced. Using multinomial logistic regression, we examined associations between multiple measures of SES and tertiles of LTL in a sample of 92 African American men between 30 to 50 years of age. Reports of greater financial strain were associated with higher odds of short versus medium LTL (odds ratio (OR)=2.21, p = 0.03). Higher income was associated with lower odds of short versus medium telomeres (OR=0.97, p = 0.04). Exploratory analyses revealed a significant interaction between educational attainment and employment status (χ 2  = 4.07, p = 0.04), with greater education associated with lower odds of short versus long telomeres only among those not employed (OR=0.10, p = 0.040). Cellular aging associated with multiple dimensions of socioeconomic adversity may contribute to poor aging-related health outcomes among African American men. Subjective appraisal of financial difficulty may impact LTL independently of objective dimensions of SES. Self-appraised success in fulfilling traditionally masculine gender roles, including being an economic provider, may be a particularly salient aspect of identity for African American men and have implications for cellular aging in this population.

Conceptual Modeling via Logic Programming

DTIC Science & Technology

1990-01-01

Define User Interface and Query Language L i1W= Ltl k.l 4. Define Procedures for Specifying Output S . Select Logic Programming Language 6. Develop ...baseline s change model. sessions and baselines. It was changed 6. Develop Methodology for C 31 Users. considerably with the advent of the window This...Model Development : Implica- for Conceptual Modeling Via Logic tions for Communications of a Cognitive Programming. Marina del Rey, Calif.: Analysis of

Strength of single-pole utility structures

Treesearch

Ronald W. Wolfe

2006-01-01

This section presents three basic methods for deriving and documenting Rn as an LTL value along with the coefficient of variation (COVR) for single-pole structures. These include the following: 1. An empirical analysis based primarily on tests of full-sized poles. 2. A theoretical analysis of mechanics-based models used in...

EAGLE can do Efficient LTL Monitoring

NASA Technical Reports Server (NTRS)

Barringer, Howard; Goldberg, Allen; Havelund, Klaus; Sen, Koushik

2003-01-01

We briefly present a rule-based framework, called EAGLE, that has been shown to be capable of defining and implementing finite trace monitoring logics, including future and past time temporal logic, extended regular expressions, real-time logics, interval logics, forms of quantified temporal logics, and so on. In this paper we show how EAGLE can do linear temporal logic (LTL) monitoring in an efficient way. We give an upper bound on the space and time complexity of this monitoring.

The functional polymorphism rs73598374:G>A (p.Asp8Asn) of the ADA gene is associated with telomerase activity and leukocyte telomere length.

PubMed

Concetti, Fabio; Carpi, Francesco M; Nabissi, Massimo; Picciolini, Matteo; Santoni, Giorgio; Napolioni, Valerio

2015-02-01

Recent evidence demonstrated a relevant role of adenosine deaminase (ADA) in replicative senescence of T cells through its capacity to modulate telomerase activity (TA). Herein, we tested the impact of the functional polymorphism ADA rs73598374:G>A (c.22G>A, p.Asp8Asn) on telomere biology, by measuring TA and leukocyte telomere length (LTL) in healthy subjects selected according to rs73598374 genotype. rs73598374-A carriers showed lower TA (P=0.019) and shorter LTL (P=0.003), respectively, compared to G/G carriers. rs73598374-A carriers showed a stronger cross-sectional age reduction of LTL (r=-0.314, P=0.005) compared to G/G carriers (r=-0.243, P=0.022). The reduced ADA activity associated to rs73598374-A variant predisposes those carriers to display higher levels of adenosine compared to G/G carriers. Consequently, it may lead to an accelerated process of replicative senescence, causing a stronger reduction of TA and in turn shorter LTL. In conclusion, the crucial role played by replicative senescence of the immune system in several human diseases and in the aging process underscores the relevance of the present findings and also spurs interest into the possible involvement of rs73598374 in shaping the susceptibility to several age-related diseases.

The functional polymorphism rs73598374:G>A (p.Asp8Asn) of the ADA gene is associated with telomerase activity and leukocyte telomere length

PubMed Central

Concetti, Fabio; Carpi, Francesco M; Nabissi, Massimo; Picciolini, Matteo; Santoni, Giorgio; Napolioni, Valerio

2015-01-01

Recent evidence demonstrated a relevant role of adenosine deaminase (ADA) in replicative senescence of T cells through its capacity to modulate telomerase activity (TA). Herein, we tested the impact of the functional polymorphism ADA rs73598374:G>A (c.22G>A, p.Asp8Asn) on telomere biology, by measuring TA and leukocyte telomere length (LTL) in healthy subjects selected according to rs73598374 genotype. rs73598374-A carriers showed lower TA (P=0.019) and shorter LTL (P=0.003), respectively, compared to G/G carriers. rs73598374-A carriers showed a stronger cross-sectional age reduction of LTL (r=−0.314, P=0.005) compared to G/G carriers (r=−0.243, P=0.022). The reduced ADA activity associated to rs73598374-A variant predisposes those carriers to display higher levels of adenosine compared to G/G carriers. Consequently, it may lead to an accelerated process of replicative senescence, causing a stronger reduction of TA and in turn shorter LTL. In conclusion, the crucial role played by replicative senescence of the immune system in several human diseases and in the aging process underscores the relevance of the present findings and also spurs interest into the possible involvement of rs73598374 in shaping the susceptibility to several age-related diseases. PMID:24896148

Higher serum phenylalanine concentration is associated with more rapid telomere shortening in men.

PubMed

Eriksson, Johan G; Guzzardi, Maria-Angela; Iozzo, Patricia; Kajantie, Eero; Kautiainen, Hannu; Salonen, Minna K

2017-01-01

Telomere length and telomere shortening are associated with age-related health outcomes. Only a few studies have been able to longitudinally report on factors that are associated with changes in telomere length in an aging population. We studied the longitudinal relation between telomere length, the change in telomere length, and circulating amino acids. A total of 812 subjects from the Helsinki Birth Cohort Study (born from 1934 to 1944), who underwent 3 clinical visits during a 10-y interval that included measurements of cardiometabolic risk factors, were included in the study. Leukocyte telomere length (LTL) was measured with the use of quantitative real-time polymerase chain reaction. Circulating branched-chain and aromatic amino acids (alanine, glycine, histidine, phenylalanine, leucine, isoleucine, valine, and tyrosine) were assessed with the use of high-throughput nuclear magnetic resonance spectroscopy. The relative ± SD LTL at a mean age of 71 y was 0.79 ± 0.27 in men and 0.89 ± 0.35 in women (P < 0.001). Of the studied amino acids, the strongest inverse association was observed between the phenylalanine concentration that was measured 5 y earlier and the LTL. This finding was significant in men (P = 0.021) and remained significant after adjustment for multiple comparisons, but it was not significant in women (P = 0.39). Longitudinally, the change in LTL over 10 y was inversely associated with the phenylalanine concentration in men (P = 0.007) but not in women (P = 0.58) after adjustment for baseline LTL, age, smoking, and percentage of body fat. The serum phenylalanine concentration is associated with telomere length and, therefore, potentially with the aging process. Because the associations reported are observational, no conclusions can be made regarding causality. Our findings support the hypothesis that cellular pathways that regulate aging are sex specific. © 2017 American Society for Nutrition.

Influences of chlorine content on emission of HCl and organic compounds in waste incineration using fluidized beds.

PubMed

Wey, M Y; Liu, K Y; Yu, W J; Lin, C L; Chang, F Y

2008-01-01

HCl and some organic compounds are the precursors of polychlorinated dibenzo-p-dioxins and furans (PCDD/Fs) in municipal solid waste incinerators. In this work, a lab-scale fluidized bed incinerator is adopted to study the relationship between the organic and the inorganic chlorine contents of artificial wastes and the emissions of HCl and organic compounds. The lower threshold limit (LTL) of chlorine content below which HCl and organic compounds are not generated is studied. Experimental results showed that organic chlorides had a greater potential to release chlorine than inorganic chlorides. The generation of organic pollutants fell, but the emissions of HCl increased with the temperature. The concentrations of chlorophenols (CPs)/chlorobenzenes (CBs) increased with chlorine contents. No LTL existed for HCl regardless of whether CaO was added. The LTL for CPs was between 0.1 and 0.3wt% of inorganic chloride, but there was none for organic sources. For CBs, the LTL was between 0.5 and 1.0wt% for inorganics at 700 and 800 degrees C, but 0.1-0.3 wt% at 700 degrees C and 0.3-0.5 wt% at 800 degrees C for organics. The production of PAHs and benzene, toluene, ethylbenzene and xylene (BTEX) was related to the surplus hydrogen ions that were not reacted with the chlorine. Adding CaO inhibited the production of HCl, CBs and CPs, but did not seriously affect PAHs and BTEX.

A Prospective Study Investigating Pre-diagnostic Leukocyte Telomere Length and Risk of Developing Rheumatoid Arthritis in Women

PubMed Central

Prescott, Jennifer; Karlson, Elizabeth W.; Orr, Esther H.; Zee, Robert Y.L.; De Vivo, Immaculata; Costenbader, Karen H.

2015-01-01

Objective To prospectively examine the association between leukocyte telomere length (LTL) and subsequent RA development in women. Methods Using a case-control design nested within the prospective Nurses’ Health Study (NHS), Nurses’ Health Study II (NHSII), and Women’s Health Study (WHS), each validated case of RA with a pre-diagnostic blood sample was matched to three controls by cohort, age, menopausal status, postmenopausal hormone therapy, and blood collection covariates. We measured telomere length in genomic DNA extracted from stored buffy coat samples using quantitative PCR. We used unconditional logistic regression to determine odds ratios (OR) and 95% confidence intervals (CI), and random-effects meta-analysis to combine study results. Results In total, we analyzed 296 incident RA cases and 827 matched controls. Mean age of diagnosis among women who developed RA was 60.5 in NHS/NHSII and 61.3 in WHS. Meta-analysis demonstrated that longer pre-diagnostic LTL was associated with increased RA risk when women in the longest vs. shortest LTL tertile were compared (OR=1.51, 95% CI=1.03–2.23; pheterogeneity=0.27). However, statistically significant between study heterogeneity was observed for the intermediate tertile category (pheterogeneity=0.008). We did not observe heterogeneity by menopausal status, inflammatory cytokine levels, age at diagnosis, age at blood collection, body mass index, seropositivity, or HLA-DRB1 shared epitope status. Conclusion Our results do not support a role for short LTL preceding RA development. PMID:26773113

Modifying police department training programs to accommodate the use of less-than-lethal technologies

NASA Astrophysics Data System (ADS)

Overlin, Trudy K.; Marts, Donna J.

1995-05-01

The Idaho National Engineering Laboratory (INEL), in response to the National Institute of Justice, less-than-lethal (LTL) technologies program, has proposed to help police departments modify their training programs to meet the challenge of training officers to use new LTL technologies. Work performed by the INEL in the development of an air bag restraint for patrol vehicles and in a technologies assessment for vehicle interdiction technologies has given laboratory researchers a better understanding of the law enforcement environment and has enabled them to evaluate potential training aids to help police departments use new technolgies and teach their officers to most efficiently and effectively use them. With the developemnt of LTL technologies as options in law enforcement comes the need for departments to adapt their current departmental training and refresher training programs to incorporate alternative weapons. This adaptation may include modifying decision making and skills training to teach officers when and how to effectively use new technologies. By assessing current programs and reviewing the training programs of other succesful agencies, a department may be able to easily adapt their current program to meet the needs of training officers in the use of LTL technologies. As litigation drove the need to develop new alternative weapons for law enforcement, it will also shape the application of the technologies when used in the field. If used incorrectly they may be ineffective, dangerous to the user, or cause more physical damage than intended. Because technology is rapidly changing, law enforcement training must keep up with the changes and meet their needs.

A facile strategy to design zeolite L crystals with tunable morphology and surface architecture.

PubMed

Lupulescu, Alexandra I; Kumar, Manjesh; Rimer, Jeffrey D

2013-05-01

Tailoring the anisotropic growth rates of materials to achieve desired structural outcomes is a pervasive challenge in synthetic crystallization. Here we discuss a method to selectively control the growth of zeolite crystals, which are used extensively in a wide range of industrial applications. This facile method cooperatively tunes crystal properties, such as morphology and surface architecture, through the use of inexpensive, commercially available chemicals with specificity for binding to crystallographic surfaces and mediating anisotropic growth. We examined over 30 molecules as potential zeolite growth modifiers (ZGMs) of zeolite L (LTL type) crystallization. ZGM efficacy was quantified through a combination of macroscopic (bulk) and microscopic (surface) investigations that identified modifiers capable of dramatically altering the cylindrical morphology of LTL crystals. We demonstrate an ability to tailor properties critical to zeolite performance, such as external porous surface area, crystal shape, and pore length, which can enhance sorbate accessibility to LTL pores, tune the supramolecular organization of guest-host composites, and minimize the diffusion path length, respectively. We report that a synergistic combination of ZGMs and the judicious adjustment of synthesis parameters produce LTL crystals with unique surface features, and a range of length-to-diameter aspect ratios spanning 3 orders of magnitude. A systematic examination of different ZGM structures and molecular compositions (i.e., hydrophobicity and binding moieties) reveal interesting physicochemical properties governing their efficacy and specificity. Results of this study suggest this versatile strategy may prove applicable for a host of framework types to produce unrivaled materials that have eluded more conventional techniques.

Low vitamin D levels predict clinical features of schizophrenia.

PubMed

Cieslak, Kristina; Feingold, Jordyn; Antonius, Daniel; Walsh-Messinger, Julie; Dracxler, Roberta; Rosedale, Mary; Aujero, Nicole; Keefe, David; Goetz, Deborah; Goetz, Raymond; Malaspina, Dolores

2014-11-01

Vitamin D plays crucial roles in neuroprotection and neurodevelopment, and low levels are commonly associated with schizophrenia. We considered if the association was spurious or causal by examining the association of Vitamin D with Leukocyte Telomere Length (LTL), a marker of cellular aging. Vitamin D levels in 22 well-characterized schizophrenia cases were examined with respect to symptoms, cognition, and functioning. LTL was assessed using quantitative polymerase chain reaction (qPCR). The results showed that 91% (20) had deficient or insufficient Vitamin D levels, which were associated with excitement and grandiosity, social anhedonia, and poverty of speech. Sex-specific analyses showed strong associations of hypovitamintosis D to negative symptoms and decreased premorbid adjustment in males, and to lesser hallucinations and emotional withdrawal, but increased anti-social aggression in females. In females LTL was furthermore associated with Vitamin D levels. This study demonstrates a relationship of low vitamin D levels with increased cellular aging in females. It is also the first study to demonstrate potential sex-specific profiles among schizophrenia cases with hypovitaminosis. Copyright © 2014 Elsevier B.V. All rights reserved.

The link between discrimination and telomere length in African American adults.

PubMed

Lee, Daniel B; Kim, Eric S; Neblett, Enrique W

2017-05-01

Prior work shows that discrimination is associated with a wide array of negative health outcomes. However, the biological mechanisms through which this link occurs require more study. We evaluated the association between discrimination and leukocyte telomere length (LTL; a biological marker of systemic aging). Cross-sectional data were from the Health and Retirement study, a study of people aged 51+ in the United States, and included 595 African American males and females. Multiple regression analyses were used to evaluate whether discrimination was independently associated with LTL. We also considered the role of potential confounders including sociodemographic factors, health factors, depressive symptoms, and stress. High discrimination was associated with shorter LTL after controlling for sociodemographic factors (b = -.034, SE = 0.14, p = .017). This association persisted in analyses that further adjusted for health factors, depressive symptoms, and stress. Results suggest that discrimination experiences accelerate biological aging in older African American males and females, alike. This finding helps advance our understanding of how discrimination generates greater disease vulnerability and premature death in African Americans. (PsycINFO Database Record (c) 2017 APA, all rights reserved).

Inflammatory Long Pentraxin 3 is Associated with Leukocyte Telomere Length in Night-Shift Workers.

PubMed

Pavanello, Sofia; Stendardo, Mariarita; Mastrangelo, Giuseppe; Bonci, Melissa; Bottazzi, Barbara; Campisi, Manuela; Nardini, Marco; Leone, Roberto; Mantovani, Alberto; Boschetto, Piera

2017-01-01

Aging is an emerging worldwide threat to public health, even in the workplace, as it links with risk of illness and death. Bewildered inflammatory responses and stressful conditions associate with age-related disorders. Additionally, circadian rhythm disruption, a critical health issue in night-shift workers, correlates with premature aging. We investigated the hypothesis of a link between altered inflammatory response, detected by plasmatic long pentraxin 3 (PTX3), and biological aging, measured by leukocyte telomere length (LTL), attrition, and possibly induced by night-shift work. Within the framework of a cross-sectional study, such possible relationships were appraised by simultaneous equation model (SEM) technique among day and night-shift hospital workers. PTX3 levels, modulated by several aging conditions [i.e., body mass index (BMI) (beta = -0.22; p  = 0.022), C-reactive protein (CRP) (beta = -0.07; p  = 0.000), and cardiovascular diseases with hypertension included (CVD) (beta = -0.12; p  = 0.000)], positively associate with LTL (coefficient = 0.15; p  = 0.033). LTL, in turn is reduced by CVD (beta = -0.15; p  = 0.000), binge drinking (beta = -0.10; p  = 0.004), and CRP (beta = -0.05; p  = 0.026). On the other hand, night-shift work, found to be remarkably free from aging risk factors [i.e., age (beta = -0.13; p  = 0.017), BMI (beta = -0.17; p  = 0.030), CVD (beta = -0.14; p  = 0.000), and binge drinking (beta = -0.13; p  = 0.000)], does associate almost significantly with reversed PTX3 (coefficient = -0.09; p  = 0.089) and even with CRP (beta = 0.17; p  = 0.000). In conclusion, the SEM analysis indicates that PTX3 is positively linked to LTL. The finding suggests a possible new role of this long pentraxin that, by orchestrating an efficient governance of inflammatory processes, may protect telomere from attrition, ensuring therefore the genetic stability of cells. The higher CRP levels among night-shift workers suggest that night-shift work is associated with increased systemic inflammation. This would make nocturnal workers more susceptible to premature aging.

Inflammatory Long Pentraxin 3 is Associated with Leukocyte Telomere Length in Night-Shift Workers

PubMed Central

Pavanello, Sofia; Stendardo, Mariarita; Mastrangelo, Giuseppe; Bonci, Melissa; Bottazzi, Barbara; Campisi, Manuela; Nardini, Marco; Leone, Roberto; Mantovani, Alberto; Boschetto, Piera

2017-01-01

Aging is an emerging worldwide threat to public health, even in the workplace, as it links with risk of illness and death. Bewildered inflammatory responses and stressful conditions associate with age-related disorders. Additionally, circadian rhythm disruption, a critical health issue in night-shift workers, correlates with premature aging. We investigated the hypothesis of a link between altered inflammatory response, detected by plasmatic long pentraxin 3 (PTX3), and biological aging, measured by leukocyte telomere length (LTL), attrition, and possibly induced by night-shift work. Within the framework of a cross-sectional study, such possible relationships were appraised by simultaneous equation model (SEM) technique among day and night-shift hospital workers. PTX3 levels, modulated by several aging conditions [i.e., body mass index (BMI) (beta = −0.22; p = 0.022), C-reactive protein (CRP) (beta = −0.07; p = 0.000), and cardiovascular diseases with hypertension included (CVD) (beta = −0.12; p = 0.000)], positively associate with LTL (coefficient = 0.15; p = 0.033). LTL, in turn is reduced by CVD (beta = −0.15; p = 0.000), binge drinking (beta = −0.10; p = 0.004), and CRP (beta = −0.05; p = 0.026). On the other hand, night-shift work, found to be remarkably free from aging risk factors [i.e., age (beta = −0.13; p = 0.017), BMI (beta = −0.17; p = 0.030), CVD (beta = −0.14; p = 0.000), and binge drinking (beta = −0.13; p = 0.000)], does associate almost significantly with reversed PTX3 (coefficient = −0.09; p = 0.089) and even with CRP (beta = 0.17; p = 0.000). In conclusion, the SEM analysis indicates that PTX3 is positively linked to LTL. The finding suggests a possible new role of this long pentraxin that, by orchestrating an efficient governance of inflammatory processes, may protect telomere from attrition, ensuring therefore the genetic stability of cells. The higher CRP levels among night-shift workers suggest that night-shift work is associated with increased systemic inflammation. This would make nocturnal workers more susceptible to premature aging. PMID:28536575

Seaweed polysaccharides (laminarin and fucoidan) as functional ingredients in pork meat: an evaluation of anti-oxidative potential, thermal stability and bioaccessibility.

PubMed

Moroney, Natasha C; O'Grady, Michael N; Lordan, Sinéad; Stanton, Catherine; Kerry, Joseph P

2015-04-20

The anti-oxidative potential of laminarin (L), fucoidan (F) and an L/F seaweed extract was measured using the DPPH free radical scavenging assay, in 25% pork (longissimus thoracis et lumborum (LTL)) homogenates (TBARS) (3 and 6 mg/mL) and in horse heart oxymyoglobin (OxyMb) (0.1 and 1 mg/mL). The DPPH activity of fresh and cooked minced LTL containing L (100 mg/g; L100), F100 and L/F100,300, and bioaccessibility post in vitro digestion (L/F300), was assessed. Theoretical cellular uptake of antioxidant compounds was measured in a transwell Caco-2 cell model. Laminarin displayed no activity and fucoidan reduced lipid oxidation but catalysed OxyMb oxidation. Fucoidan activity was lowered by cooking while the L/F extract displayed moderate thermal stability. A decrease in DPPH antioxidant activity of 44.15% and 36.63%, after 4 and 20 h respectively, indicated theoretical uptake of L/F antioxidant compounds. Results highlight the potential use of seaweed extracts as functional ingredients in pork.

Seaweed Polysaccharides (Laminarin and Fucoidan) as Functional Ingredients in Pork Meat: An Evaluation of Anti-Oxidative Potential, Thermal Stability and Bioaccessibility

PubMed Central

Moroney, Natasha C.; O’Grady, Michael N.; Lordan, Sinéad; Stanton, Catherine; Kerry, Joseph P.

2015-01-01

The anti-oxidative potential of laminarin (L), fucoidan (F) and an L/F seaweed extract was measured using the DPPH free radical scavenging assay, in 25% pork (longissimus thoracis et lumborum (LTL)) homogenates (TBARS) (3 and 6 mg/mL) and in horse heart oxymyoglobin (OxyMb) (0.1 and 1 mg/mL). The DPPH activity of fresh and cooked minced LTL containing L (100 mg/g; L100), F100 and L/F100,300, and bioaccessibility post in vitro digestion (L/F300), was assessed. Theoretical cellular uptake of antioxidant compounds was measured in a transwell Caco-2 cell model. Laminarin displayed no activity and fucoidan reduced lipid oxidation but catalysed OxyMb oxidation. Fucoidan activity was lowered by cooking while the L/F extract displayed moderate thermal stability. A decrease in DPPH antioxidant activity of 44.15% and 36.63%, after 4 and 20 h respectively, indicated theoretical uptake of L/F antioxidant compounds. Results highlight the potential use of seaweed extracts as functional ingredients in pork. PMID:25903283

Wrist Traction During MR Arthrography Improves Detection of Triangular Fibrocartilage Complex and Intrinsic Ligament Tears and Visibility of Articular Cartilage.

PubMed

Lee, Ryan K L; Griffith, James F; Ng, Alex W H; Nung, Ryan C H; Yeung, David K W

2016-01-01

The purpose of this study was to assess the effects of traction during MR arthrography of the wrist on joint space widening, cartilage visibility, and detection of tears of the triangular fibrocartilage complex (TFCC) and intrinsic ligaments. A prospective study included 40 wrists in 39 patients (25 men, 14 women; mean age, 35 years). MR arthrography was performed with a 3-T MRI system with and without axial traction. Two radiologists independently measured wrist and carpal joint space widths and semiquantitatively graded articular cartilage visibility. Using conventional arthrography as the reference standard and working in consensus, they assessed for the presence of tears of the TFCC, lunotriquetral ligament (LTL), and scapholunate ligament (SLL). Visibility of a tear before traction was compared with visibility after traction. With traction, all joint spaces in the wrist and carpus were significantly widened (change, 0.15-1.01 mm; all p < 0.006). Subjective cartilage visibility of all joint spaces improved after traction (all p ≤ 0.048) except for that of the radioscaphoid space, which was well visualized even before traction. Conventional arthrography depicted 24 TFCC tears, seven LTL tears, and three SLL tears. The accuracy of tear detection improved after traction for the TFCC (98% after traction vs 83% before traction), the LTL (100% vs 88%), and the SLL (100% vs 95%). Tear visibility improved after traction for 54% of TFCC tears, 71% of LTL tears, and 66% of SLL tears. Wrist MR arthrography with axial traction significantly improved the visibility of articular cartilage and the detection and visibility of tears of the TFCC and intrinsic ligaments. The results favor more widespread use of traction during MR arthrography of the wrist.

Physical activity and telomere length in U.S. men and women: An NHANES investigation.

PubMed

Tucker, Larry A

2017-07-01

The principal objective was to determine the extent to which physical activity (PA) accounts for differences in leukocyte telomere length (LTL) in a large random sample of U.S. adults. Another purpose was to assess the extent to which multiple demographic and lifestyle covariates affect the relationship between PA and LTL. A total of 5823 adults from the National Health and Nutrition Examination Survey (NHANES 1999-2002) were studied cross-sectionally. Employing the quantitative polymerase chain reaction method, LTL was compared to standard reference DNA. PA was indexed using MET-minutes using self-reported frequency, intensity, and duration of participation in 62 physical activities. Covariates were controlled statistically. Telomeres were 15.6 base pairs shorter for each year of chronological age (F=723.2, P<0.0001). PA was inversely related to LTL after adjusting for all the covariates (F=8.3, P=0.0004). Telomere base pair differences between adults with High activity and those in the Sedentary, Low, and Moderate groups were 140, 137, and 111, respectively. Adults with High activity were estimated to have a biologic aging advantage of 9years (140 base pairs÷15.6) over Sedentary adults. The difference in cell aging between those with High and Low activity was also significant, 8.8years, as was the difference between those with High and Moderate PA (7.1years). Overall, PA was significantly and meaningfully associated with telomere length in U.S. men and women. Evidently, adults who participate in high levels of PA tend to have longer telomeres, accounting for years of reduced cellular aging compared to their more sedentary counterparts. Copyright © 2017 Elsevier Inc. All rights reserved.

Comparison of conventional MRI and MR arthrography in the evaluation of wrist ligament tears: A preliminary experience

PubMed Central

Pahwa, Shivani; Srivastava, Deep N; Sharma, Raju; Gamanagatti, Shivanand; Kotwal, Prakash P; Sharma, Vijay

2014-01-01

Aims: To compare conventional magnetic resonance imaging (MRI) and direct magnetic resonance (MR) arthrography in the evaluation of triangular fibrocartilage complex (TFCC) and intrinsic wrist ligament tears. Materials and Methods: T1-weighted, fat suppressed (FS) proton density plus T2-weighted (FS PD/T2), 3D multiple-echo data image combination (MEDIC) sequences and direct MR arthrography were performed in 53 patients with wrist pain. Images were evaluated for the presence and location of TFCC, scapholunate ligament (SLL) and lunatotriquetral ligament (LTL) tears, and imaging findings were compared with operative findings in 16 patients who underwent arthroscopy or open surgery (gold standard). Results: Sixteen patients underwent arthroscopy/open surgery: 12 TFCC tears were detected arthroscopically out of which 9 were detected on FS PD/T2 sequence, 10 on MEDIC sequence, and all 12 were detected on MR arthrography. The sensitivities of FS PD/T2, MEDIC sequences, and MR arthrography in the detection of TFCC tears were 75%, 83.3%, and 100%, respectively. Out of the eight arthroscopically confirmed SLL tears, three tears were detected on FS PD/T2 sequence, five on MEDIC sequence, and all eight were visualized on MR arthrography. The sensitivities of FS PD/T2, MEDIC sequences, and MR arthrography in detecting SLL tears were 37.5%, 62.5%, and 100%, respectively. One arthroscopically confirmed LTL tear was diagnosed on FS PD/T2 sequence, three on MEDIC sequence, and all five arthroscopically confirmed LTL tears were detected with MR arthrography. The sensitivities of PD, MEDIC sequences, and MR arthrography in detecting LTL tears were 20%, 40%, and 100%, respectively. Conclusions: MR arthrography is the most sensitive and specific imaging modality for the evaluation of wrist ligament tears. PMID:25114389

The Effect of Polymorphisms in DNA Repair Genes and Carcinogen Metabolizers on Leukocyte Telomere Length: A Cohort of Healthy Spanish Smokers.

PubMed

Verde, Zoraida; Reinoso-Barbero, Luis; Chicharro, Luis; Resano, Pilar; Sánchez-Hernández, Ignacio; Rodríguez González-Moro, Jose Miguel; Bandrés, Fernando; Gómez-Gallego, Félix; Santiago, Catalina

2016-04-01

Smoking implies exposure to carcinogenic agents that causes DNA damage, which could be suspected to enhance telomere attrition. To protect and deal with DNA damage, cells possess mechanisms that repair and neutralize harmful substances. Polymorphisms altering DNA repair capacity or carcinogen metabolism may lead to synergistic effects with tobacco carcinogen-induced shorter telomere length independently of cancer interaction. The aim of this study was to explore the association between leukocyte telomere length (LTL) and several genetic polymorphisms in DNA repair genes and carcinogen metabolizers in a cohort of healthy smokers. We evaluated the effect of six genetic polymorphisms in cytochrome P1A1 (Ile462Val), XRCC1 (Arg399Gln), APEX1 (Asp148Glu), XRCC3 (Thr241Met), and XPD (Asp312Asn; Lys751Gln) on LTL in a cohort of 145 healthy smokers in addition to smoking habits. Logistic regression analysis showed an association between XRCC1 399Gln allele and shorter telomere length (OR = 5.03, 95% CI = 1.08% to 23.36%). There were not association between the rest of polymorphisms analyzed and LTL. Continuous exposure to tobacco could overwhelm the DNA repair machinery, making the effect of the polymorphisms that reduce repair capacity more pronounced. Analyzing the function of smoking-induced DNA-repair genes and LTL is an important goal in order to identify therapeutic targets to treat smoking-induced diseases. © The Author 2015. Published by Oxford University Press on behalf of the Society for Research on Nicotine and Tobacco. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Prospective Coronary Heart Disease Screening in Asymptomatic Hodgkin Lymphoma Patients Using Coronary Computed Tomography Angiography: Results and Risk Factor Analysis

DOE Office of Scientific and Technical Information (OSTI.GOV)

Girinsky, Theodore, E-mail: girinsky.theodore@orange.fr; M’Kacher, Radhia; Lessard, Nathalie

Purpose: To prospectively investigate the coronary artery status using coronary CT angiography (CCTA) in patients with Hodgkin lymphoma treated with combined modalities and mediastinal irradiation. Methods and Materials: All consecutive asymptomatic patients with Hodgkin lymphoma entered the study during follow-up, from August 2007 to May 2012. Coronary CT angiography was performed, and risk factors were recorded along with leukocyte telomere length (LTL) measurements. Results: One hundred seventy-nine patients entered the 5-year study. The median follow-up was 11.6 years (range, 2.1-40.2 years), and the median interval between treatment and the CCTA was 9.5 years (range, 0.5-40 years). Coronary artery abnormalities were demonstrated in 46 patientsmore » (26%). Coronary CT angiography abnormalities were detected in nearly 15% of the patients within the first 5 years after treatment. A significant increase (34%) occurred 10 years after treatment (P=.05). Stenoses were mostly nonostial. Severe stenoses were observed in 12 (6.7%) of the patients, entailing surgery with either angioplasty with stent placement or bypass grafting in 10 of them (5.5%). A multivariate analysis demonstrated that age at treatment, hypertension, and hypercholesterolemia, as well as radiation dose to the coronary artery origins, were prognostic factors. In the group of patients with LTL measurements, hypertension and LTL were the only independent risk factors. Conclusions: The findings suggest that CCTA can identify asymptomatic individuals at risk of acute coronary artery disease who might require either preventive or curative measures. Conventional risk factors and the radiation dose to coronary artery origins were independent prognostic factors. The prognostic value of LTL needs further investigation.« less

QTL mapping of leukocyte telomere length in American Indians: The Strong Heart Family Study

PubMed Central

Lin, Jue; Matsuguchi, Tet; Blackburn, Elizabeth; Best, Lyle G.; Lee, Elisa T.; MacCluer, Jean W.; Cole, Shelley A.; Zhao, Jinying

2013-01-01

Telomeres play a central role in cellular senescence and are associated with a variety of age-related disorders such as dementia, Alzheimer's disease and atherosclerosis. Telomere length varies greatly among individuals of the same age, and is heritable. Here we performed a genome-wide linkage scan to identify quantitative trait loci (QTL) influencing leukocyte telomere length (LTL) measured by quantitative PCR in 3,665 American Indians (aged 14 – 93 years) from 94 large, multi-generational families. All participants were recruited by the Strong Heart Family Study (SHFS), a prospective study to identify genetic factors for cardiovascular disease and its risk factors in American Indians residing in Oklahoma, Arizona and Dakota. LTL heritability was estimated to be between 51% and 62%, suggesting a strong genetic predisposition to interindividual variation of LTL in this population. Significant QTLs were localized to chromosome 13 (Logarithm of odds score (LOD) = 3.9) at 13q12.11, to 18q22.2 (LOD = 3.2) and to 3p14.1 (LOD = 3.0) for Oklahoma. This is the first study to identify susceptibility loci influencing leukocyte telomere variation in American Indians, a minority group suffering from a disproportionately high rate of type 2 diabetes and other age-related disorders. PMID:24036517

Young adult survivors of childhood acute lymphoblastic leukemia show evidence of chronic inflammation and cellular aging.

PubMed

Ariffin, Hany; Azanan, Mohamad Shafiq; Abd Ghafar, Sayyidatul Syahirah; Oh, Lixian; Lau, Kee Hie; Thirunavakarasu, Tharshanadhevasheri; Sedan, Atiqah; Ibrahim, Kamariah; Chan, Adelyne; Chin, Tong Foh; Liew, Fong Fong; Jeyamogan, Shareni; Rosli, Erda Syerena; Baharudin, Rashidah; Yap, Tsiao Yi; Skinner, Roderick; Lum, Su Han; Hainaut, Pierre

2017-11-01

Large epidemiologic studies have reported the premature onset of age-related conditions, such as ischemic heart disease and diabetes mellitus, in childhood cancer survivors, decades earlier than in their peers. The authors investigated whether young adult survivors of childhood acute lymphoblastic leukemia (ALL) have a biologic phenotype of cellular ageing and chronic inflammation. Plasma inflammatory cytokines were measured using a cytometric bead array in 87 asymptomatic young adult survivors of childhood ALL (median age, 25 years; age range, 18-35 years) who attended annual follow-up clinic and compared with healthy, age-matched and sex-matched controls. Leukocyte telomere length (LTL) was measured using Southern blot analysis. Survivors had significant elevation of plasma interleukin-2 (IL-2), IL-10, IL-17a, and high-sensitivity C-reactive protein levels (all P < .05). A raised high-sensitivity C-reactive protein level (>0.8 mg/dL) was related to increased odds of having metabolic syndrome (odds ratio, 7.256; 95% confidence interval, 1.501-35.074). Survivors also had significantly shorter LTL compared with controls (median, 9866 vs 10,392 base pairs; P = .021). Compared with published data, LTL in survivors was similar to that in healthy individuals aged 20 years older. Survivors who received cranial irradiation had shorter LTL compared with those who had not (P = .013). Asymptomatic young adult survivors of childhood ALL demonstrate a biologic profile of chronic inflammation and telomere attrition, consistent with an early onset of cellular processes that drive accelerated aging. These processes may explain the premature development of age-related chronic conditions in childhood cancer survivors. Understanding their molecular basis may facilitate targeted interventions to disrupt the accelerated aging process and its long-term impact on overall health. Cancer 2017;123:4207-4214. © 2017 American Cancer Society. © 2017 American Cancer Society.

Arsenic exposure, genetic susceptibility and leukocyte telomere length in an Italian young adult population.

PubMed

Borghini, Andrea; Faita, Francesca; Mercuri, Antonella; Minichilli, Fabrizio; Bustaffa, Elisa; Bianchi, Fabrizio; Andreassi, Maria Grazia

2016-09-01

Arsenic-induced health effects may be associated with critically shortened telomeres. However, few data are available on the effects of arsenic exposure on telomere length. The aim of this study was to investigate the effects of chronic arsenic exposure on leukocyte telomere length (LTL) as well as the contribution of common polymorphisms in genes implicated in arsenic metabolism (GSTT1 and GSTM1) and DNA repair (hOGG1 and XRCC1). A group of 241 healthy subjects was enrolled from four areas of Italy known to be affected by natural or anthropogenic arsenic pollution. Urine samples were tested for inorganic As (iAs), monomethylarsinic (MMA) and dimethylarsinic acid (DMA). LTL was evaluated by quantitative reverse transcriptase polymerase chain reaction (qRT-PCR). Genotyping was carried out by PCR-RFLP on leukocyte DNA. In multiple linear regression analysis, LTL was significantly and inversely correlated with age (β = -0.231, P = 0.006) and showed a certain trend toward significance with iAs urinary concentration (log10 iAs, β = -0.106, P = 0.08). The genotype distribution showed significant associations between GSTT1 and the As concentration (log10 iAs, P = 0.01) and metabolite patterns (log10 DMA, P = 0.05) in the urine. However, GST genes did not interact with arsenic exposure in the modulation of LTL. Conversely, the combined presence of a higher level of iAs + MMA + DMA ≥ 19.3 μg/l (F = 6.0, P interaction = 0.01), Asi ≥ 3.86 (F = 3.9, P interaction = 0.04) μg/l, iAs + MMA + DMA ≥ 15 μg/l (F = 4.2, P interaction = 0.04) and hOGG1 Cys allele was associated with a significantly lower LTL. An interaction between XRCC1 Arg399Gln and arsenic exposure was also observed (all P interaction = 0.04). These findings suggest that telomere shortening may represent a mechanism that contributes to arsenic-related disease. The interaction of hOGG1 and XRCC1 DNA repair polymorphisms and exposure enhances telomeric DNA damage. Future studies are warranted to understand better the epidemiologic impact of arsenic on telomere function as well as to identify the subgroups of exposed subjects who need better health surveillance. © The Author 2016. Published by Oxford University Press on behalf of the UK Environmental Mutagen Society. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Effect of Extra-Framework Cations of LTL Nanozeolites to Inhibit Oil Oxidation

NASA Astrophysics Data System (ADS)

Tan, Kok-Hou; Cham, Hooi-Ying; Awala, Hussein; Ling, Tau Chuan; Mukti, Rino R.; Wong, Ka-Lun; Mintova, Svetlana; Ng, Eng-Poh

2015-06-01

Lubricant oils take significant part in current health and environmental considerations since they are an integral and indispensable component of modern technology. Antioxidants are probably the most important additives used in oils because oxidative deterioration plays a major role in oil degradation. Zeolite nanoparticles (NPs) have been proven as another option as green antioxidants in oil formulation. The anti-oxidative behavior of zeolite NPs is obvious; however, the phenomenon is still under investigation. Herein, a study of the effect of extra-framework cations stabilized on Linde Type L (LTL) zeolite NPs (ca. 20 nm) on inhibition of oxidation in palm oil-based lubricant oil is reported. Hydrophilic LTL zeolites with a Si/Al ratio of 3.2 containing four different inorganic cations (Li+, Na+, K+, Ca2+) were applied. The oxidation of the lubricant oil was followed by visual observation, colorimetry, fourier transform infrared (FTIR) spectroscopy, 1H NMR spectroscopy, total acid number (TAN), and rheology analyses. The effect of extra-framework cations to slow down the rate of oil oxidation and to control the viscosity of oil is demonstrated. The degradation rate of the lubricant oil samples is decreased considerably as the polarizability of cation is increased with the presence of zeolite NPs. More importantly, the microporous zeolite NPs have a great influence in halting the steps that lead to the polymerization of the oils and thus increasing the lifetime of oils.

Circulating Prostate-Specific Antigen and Telomere Length in a Nationally Representative Sample of Men Without History of Prostate Cancer.

PubMed

Wulaningsih, Wahyu; Astuti, Yuliana; Matsuguchi, Tetsuya; Anggrandariyanny, Putri; Watkins, Johnathan

2017-01-01

We investigated the association of prostate-specific antigen (PSA) with leukocyte telomere length, which may be altered in preclinical prostate malignancies. This study was based on the 2001-2002 U.S. National Health and Nutrition Examination Survey (NHANES). A subsample of 1,127 men aged 40-85 years without prior history of prostate cancer who provided informed consent and blood samples were selected. Leukocyte telomere length (LTL) relative to standard DNA reference (T/S ratio) was quantified by polymerase chain reaction (PCR). Survey-weighted multivariable linear regression was performed to examine T/S ratio across quintiles of total and free PSA and free-to-total PSA ratio (%fPSA). A sensitivity analysis was performed by excluding men dying from prostate cancer during follow-up through to December 31, 2006. Stratification analyses were carried out to assess any effect modification by age group, race, body mass index (BMI), and levels of C-reactive protein (CRP), a marker of inflammation. Higher total PSA levels were associated to longer LTL, with approximately 8% increase in log-transformed T/S ratio (95% confidence interval [CI]: 2-13%) among men in the highest quintile of total PSA compared to the lowest in the fully adjusted model (P trend  = 0.01). No significant association was found for free PSA or %fPSA, although nonlinearity between all PSA measures and T/S ratio was indicated. Similar results were found after excluding men who died from prostate cancer during follow-up. We also found the associations between total PSA and T/S ratio to be strongest among non-Hispanic blacks, non-obese men (BMI <30 kg/m 2 ), and those with low CRP. However, a significant interaction was only found between total PSA and race/ethnicity (P interaction  = 0.01). Total PSA levels were strongly associated to LTL, particularly among non-Hispanic blacks. Our findings support a potential link between PSA and specific mechanisms contributing to prostate cancer development. Prostate 77:22-32, 2017. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

Avocado waste for finishing pigs: Impact on muscle composition and oxidative stability during chilled storage.

PubMed

Hernández-López, Silvia H; Rodríguez-Carpena, Javier G; Lemus-Flores, Clemente; Grageola-Nuñez, Fernando; Estévez, Mario

2016-06-01

The utilization of agricultural waste materials for pig feeding may be an interesting option for reducing production costs and contributing to sustainability and environmental welfare. In the present study, a mixed diet enriched with avocado waste (TREATED) is used for finishing industrial genotype pigs. The muscle longissimus thoracis et lomborum (LTL) from TREATED pigs was analyzed for composition and oxidative and color stability and compared with muscles obtained from pigs fed a CONTROL diet. Dietary avocado had significant impact on the content and composition of intramuscular fat (IMF), reducing the lipid content in LTL muscles and increasing the degree of unsaturation. This did not increase the oxidative instability of samples. On the contrary, muscles from TREATED pigs had significantly lower lipid and protein oxidation rates during chilled storage. The color of the muscles from TREATED pigs was also preserved from oxidation. Copyright © 2016 Elsevier Ltd. All rights reserved.

Reduced telomere length is not associated with early signs of vascular aging in young men born after intrauterine growth restriction: a paradox?

PubMed

Laganović, Mario; Bendix, Laila; Rubelj, Ivica; Kirhmajer, Majda Vrkić; Slade, Neda; Lela, Ivana Vuković; Premužić, Vedran; Nilsson, Peter M; Jelaković, Bojan

2014-08-01

The mechanisms that increase cardiovascular risk in individuals born small for gestational age (SGA) are not well understood. Telomere shortening has been suggested to be a predictor of disease onset. Our aim was to determine whether impaired intrauterine growth is associated with early signs of vascular aging and whether telomere length could be a biomarker of this pathway. One hundred and fourteen healthy young men born SGA or after normal pregnancy [appropriate for gestational age (AGA)] were enrolled. Patient data were gathered from questionnaires and clinical exams, including blood pressure (BP) measurement routine laboratory analyses, and carotid intima-media thickness (cIMT). Leukocyte telomere length (LTL) was assessed by quantitative PCR. Birth data were obtained from medical records. The SGA group had significantly higher pulse pressure and cIMT, and a trend to increased SBP and heart rate in comparison to the AGA group. Interestingly, SGA men exhibited a 42% longer LTL than the AGA group. LTL was inversely associated with age, BMI, BP and birth parameters. In multiple regression analysis, BMI was the key determinant of SBP and cIMT. Young men born SGA show early signs of vascular aging. Unexpectedly, in our cohort, the SGA group had longer telomeres than the normal controls. Although longer telomeres are predictive of better health in the future, our findings could indicate a faster telomere attrition rate and probable early onset of cardiovascular risk in SGA participants. Follow-up of this cohort will clarify hypothesis and validate telomere dynamics as indicators of future health risks.

Variants in TERT influencing telomere length are associated with paranoid schizophrenia risk.

PubMed

Rao, Shuquan; Ye, Ning; Hu, Huiling; Shen, Yan; Xu, Qi

2016-04-01

Schizophrenia is one of the most severe psychiatric disorders, with a high heritability of up to 80%. Several studies have reported telomere dysfunction in schizophrenia, and common variants in the telomerase reverse transcriptase (TERT) gene. TERT is a key component of the telomerase complex that maintains telomere length by addition of telomere repeats to telomere ends, and has repeatedly shown association with mean lymphocyte telomere length (LTL). Thus, we hypothesized that TERT may be a novel susceptibility gene for schizophrenia. Using a Taqman protocol, we genotyped eight tag SNPs from the TERT locus in 1,072 patients with paranoid schizophrenia and 1,284 control subjects from a Chinese Han population. We also measured mean LTL in 98 cases and 109 controls using a quantitative PCR-based technique. Chi-square tests showed that two SNPs, rs2075786 (P = 0.0009, OR = 0.76, 95%CI = 0.65-0.90) and rs4975605 (P = 0.0026, OR = 0.73, 95%CI = 0.60-0.90), were associated with a protective effect, while rs10069690 was associated with risk of paranoid schizophrenia (P = 0.0044, OR = 1.23, 95%CI = 1.07-1.42). Additionally, the rs2736118-rs2075786 haplotype showed significant association with paranoid schizophrenia (P = 0.0013). Moreover, mean LTL correlated with rs2075786 genotypes was significantly shorter in the patient group than the control group. The present results suggest that the TERT gene may be a novel candidate involved in the development of paranoid schizophrenia. © 2016 Wiley Periodicals, Inc.

Premature Spinal Bone Loss in Women Living with HIV is Associated with Shorter Leukocyte Telomere Length

PubMed Central

Pick, Neora; Mai, Alice; Kidson, Kristen; Chu, Jackson; Côté, Hélène C. F.; Maan, Evelyn J.; Goshtasebi, Azita; Money, Deborah M.

2018-01-01

With advances in combination antiretroviral therapy (cART), people living with HIV are now surviving to experience aging. Evidence suggests that individuals living with HIV are at greater risk for low bone mineral density (BMD), osteoporosis, and fractures. Better understanding of the pathophysiology of bone health in women living with HIV (WLWH) is important for treatment strategies. The goal of this study was to explore new biological factors linked to low BMD in WLWH. Standardized BMD measures of WLWH were compared to reference values from an unselected population of women from the same geographical region of the same age range. Linear regression analysis was used to assess relationships among health-related characteristics, cellular aging (measured by leukocyte telomere length; LTL), cART, and BMD of WLWH. WLWH (n = 73; mean age 43 ± 9 years) had lower BMD Z-scores at the lumbar spine (LS) (mean difference = −0.39, p < 0.001) and total hip (TH) (−0.29, p = 0.012) relative to controls (n = 290). WLWH between 50 and 60 years (n = 17) had lower Z-scores at the LS (p = 0.008) and TH (p = 0.027) compared to controls (n = 167). Among WLWH, LS BMD was significantly associated with LTL (R2 = 0.09, p = 0.009) and BMI (R2 = 0.06, p = 0.042). Spinal BMD was adversely affected in WLWH. Reduction of LTL was strongly associated with lower BMD and may relate to its pathophysiology and premature aging in WLWH. PMID:29783641

Is Post-Traumatic Stress Disorder Associated with Premature Senescence? A Review of the Literature

PubMed Central

Lohr, James B.; Palmer, Barton W.; Eidt, Carolyn A.; Aailaboyina, Smitha; Mausbach, Brent T.; Wolkowitz, Owen M.; Thorp, Steven R.; Jeste, Dilip V.

2015-01-01

Post-Traumatic Stress Disorder (PTSD) has major public health significance. Evidence that PTSD may be associated with premature senescence (early or accelerated aging) would have major implications for quality of life and healthcare policy. We conducted a comprehensive review of published empirical studies relevant to early aging in PTSD. Our search included the PubMed, PsycINFO and PILOTS databases for empirical reports published since the year 2000 relevant to early senescence and PTSD, including: (1) biomarkers of senescence (leukocyte telomere length (LTL) and pro-inflammatory markers), (2) prevalence of senescence-associated medical conditions, and (3) mortality rates. All six studies examining LTL indicated reduced LTL in PTSD (pooled Cohen’s d = 0.76). We also found consistent evidence of increased pro-inflammatory markers in PTSD (mean Cohen’s ds), including C-reactive protein = 0.18, Interleukin-1 beta = 0.44, Interleukin-6 = 0.78, and tumor necrosis factor alpha = 0.81. The majority of reviewed studies also indicated increased medical comorbidity among several targeted conditions known to be associated with normal aging, including cardiovascular disease, type 2 diabetes mellitus, gastrointestinal ulcer disease, and dementia. We also found seven of 10 studies indicated PTSD to be associated with earlier mortality (average HR = 1.29). In short, evidence from multiple lines of investigation suggests that PTSD may be associated with a phenotype of accelerated senescence. Further research is critical to understand the nature of this association. There may be a need to re-conceptualize PTSD beyond the boundaries of mental illness, and instead as a full systemic disorder. PMID:25959921

Intraoperative gamma probe guidance with 99mTc-pertechnetate in the completion thyroidectomy.

PubMed

Aras, Gülseren; Gültekin, Salih Sinan; Küçük, Nuriye Ozlem; Demirer, Seher; Tuğ, Tuğbay

2009-07-01

Intraoperative gamma probe (GP) guidance with (99m)Tc-pertechnetate in the completion total thyroidectomy after a first thyroidectomy was investigated in this prospective study. The study group comprises of fourteen consecutive patients (14 females, age mean 50.2 +/- 12.0 years, age range 29-73 years). All patients underwent a second thyroidectomy due to inadequate (5/14 patients) and complementary (9/14 patients) interventions. Serum-free three iodothyronine, free thyroxin and thyroid stimulating hormone measurements, a neck ultrasonography (USG) and thyroid scintigraphy (TS) were performed in the preoperative and postoperative period. After a 185 MBq (5 mCi) injection of (99m)Tc-pertechnetate, background (BG), left thyroid lobe (LTL), right thyroid lobe (RTL) and pyramidal tyroid lobe (PTL) regions were counted in time before and after resection of thyroid remnants by intraoperative GP. All resection materials were evaluated by histopathologic examination. Preoperative TSH was less than 30 mIU/mL (mean 21 +/- 7) in all patients. Functioning thyroid remnants were shown in 13/14 patients on the preoperative TS and USG, which were diagnosed by USG in one but by TS in other one. We calculated that percentage median (minimum-maximum) values were 220.90% (56.00-411.11%) in LTL, 80.43% (11.54-471.05%) in RTL and 66.60% (-3.33 to 158.33%) in PTL for counts before resection, on the other hand, 15.96% (-20.55 to 47.62%) in LTL, 17.59% (-15.07 to 38.46%) in RTL and 17.59% (-1.96 to 57.14%) in PTL regions for counts after resection. There were statistically significant differences between these values belonging to before and after resection for LTL (p = 0.001), RTL (p = 0.001) and PTL (p = 0.008). Bilateral small foci in a patient and unilateral focus in other patient were observed in postoperative TS. Unilateral focus was detected on the RTL by GP, but not bilateral foci. Postoperative TSH levels increased to 30 mIU/mL (mean 69 +/- 26) at least. There was a statistically significant difference between preoperative and postoperative TSH values (p < 0.001). Histopathologic confirmation revealed that all removed materials were the thyroid tissues. Gamma probe guidance with (99m)Tc-pertechnetate seemed to be a good option and easy available method in patients undergoing the completion total thyroidectomy.

Robust Satisficing Decision Making for Unmanned Aerial Vehicle Complex Missions under Severe Uncertainty

PubMed Central

Ji, Xiaoting; Niu, Yifeng; Shen, Lincheng

2016-01-01

This paper presents a robust satisficing decision-making method for Unmanned Aerial Vehicles (UAVs) executing complex missions in an uncertain environment. Motivated by the info-gap decision theory, we formulate this problem as a novel robust satisficing optimization problem, of which the objective is to maximize the robustness while satisfying some desired mission requirements. Specifically, a new info-gap based Markov Decision Process (IMDP) is constructed to abstract the uncertain UAV system and specify the complex mission requirements with the Linear Temporal Logic (LTL). A robust satisficing policy is obtained to maximize the robustness to the uncertain IMDP while ensuring a desired probability of satisfying the LTL specifications. To this end, we propose a two-stage robust satisficing solution strategy which consists of the construction of a product IMDP and the generation of a robust satisficing policy. In the first stage, a product IMDP is constructed by combining the IMDP with an automaton representing the LTL specifications. In the second, an algorithm based on robust dynamic programming is proposed to generate a robust satisficing policy, while an associated robustness evaluation algorithm is presented to evaluate the robustness. Finally, through Monte Carlo simulation, the effectiveness of our algorithms is demonstrated on an UAV search mission under severe uncertainty so that the resulting policy can maximize the robustness while reaching the desired performance level. Furthermore, by comparing the proposed method with other robust decision-making methods, it can be concluded that our policy can tolerate higher uncertainty so that the desired performance level can be guaranteed, which indicates that the proposed method is much more effective in real applications. PMID:27835670

Robust Satisficing Decision Making for Unmanned Aerial Vehicle Complex Missions under Severe Uncertainty.

PubMed

Ji, Xiaoting; Niu, Yifeng; Shen, Lincheng

2016-01-01

This paper presents a robust satisficing decision-making method for Unmanned Aerial Vehicles (UAVs) executing complex missions in an uncertain environment. Motivated by the info-gap decision theory, we formulate this problem as a novel robust satisficing optimization problem, of which the objective is to maximize the robustness while satisfying some desired mission requirements. Specifically, a new info-gap based Markov Decision Process (IMDP) is constructed to abstract the uncertain UAV system and specify the complex mission requirements with the Linear Temporal Logic (LTL). A robust satisficing policy is obtained to maximize the robustness to the uncertain IMDP while ensuring a desired probability of satisfying the LTL specifications. To this end, we propose a two-stage robust satisficing solution strategy which consists of the construction of a product IMDP and the generation of a robust satisficing policy. In the first stage, a product IMDP is constructed by combining the IMDP with an automaton representing the LTL specifications. In the second, an algorithm based on robust dynamic programming is proposed to generate a robust satisficing policy, while an associated robustness evaluation algorithm is presented to evaluate the robustness. Finally, through Monte Carlo simulation, the effectiveness of our algorithms is demonstrated on an UAV search mission under severe uncertainty so that the resulting policy can maximize the robustness while reaching the desired performance level. Furthermore, by comparing the proposed method with other robust decision-making methods, it can be concluded that our policy can tolerate higher uncertainty so that the desired performance level can be guaranteed, which indicates that the proposed method is much more effective in real applications.

Nutritional geometry of calcium and phosphorus nutrition in broiler chicks. Growth performance, skeletal health and intake arrays.

PubMed

Bradbury, E J; Wilkinson, S J; Cronin, G M; Thomson, P C; Bedford, M R; Cowieson, A J

2014-07-01

The interaction between calcium (Ca) and non-phytate phosphorus (nPP) in broiler nutrition and skeletal health is highly complex with many factors influencing their digestion, absorption and utilisation. The use of an investigative model such as the geometric framework allows a graphical approach to explore these complex interactions. A total of 600 Ross 308-day-old male broiler chicks were allocated to one of 15 dietary treatments with five replicates and eight birds per replicate. Dietary treatments were formulated to one of three total densities of total Ca+nPP; high (15 g/kg), medium (13.5 g/kg) and low (12 g/kg) and at each density there were five different ratios of Ca : nPP (4, 2.75, 2.1, 1.5 and 1.14 : 1). Weekly performance data was collected and at the end of the experiment birds were individually weighed and the right leg removed for tibia ash analysis. Skeletal health was assessed using the latency to lie (LTL) at day 27. At low Ca and high nPP as well as high Ca and low nPP diets, birds had reduced feed intake, BW gain, poorer feed efficiency and lower tibia ash, resulting in a significant interaction between dietary Ca and nPP (P<0.05). LTL times were negatively influenced by diets having either a broad ratio (high Ca, low nPP) or too narrow a ratio (low Ca, high nPP) indicating that shorter LTL times may be influenced by the ratio of Ca : nPP rather than absolute concentrations of either mineral. The calculated intake arrays show that broilers more closely regulate Ca intake than nPP intake. Broilers are willing to over consume nPP to defend a Ca intake target more so than they are willing to over consume Ca to defend an nPP target. Overall dietary nPP was more influential on performance metrics, however, from the data it may appear that birds prioritise Ca intake over nPP and broadly ate to meet this requirement. As broilers are more willing to eat to a Ca intake target rather than an nPP intake target, this emphasises the importance of formulating diets to a accurately balanced density of Ca : nPP considering the biological importance of both minerals.

Analyzing and quantifying the impact of congestion on LTL industry costs and performance in the Portland metropolitan region.

DOT National Transportation Integrated Search

2012-07-01

Increased congestion during peak morning and afternoon periods in urban areas is increasing logistics costs. In addition, environmental, social, : and political pressures to limit the impacts associated with CO2 emissions are mounting rapidly. A key ...

U.S. EPA, Pesticide Product Label, , 08/11/1975

EPA Pesticide Factsheets

2011-04-21

: l i. -, Hif,'." , dlllllt.-fd.l!.1 ~~d!~_ /;[11:' !h;· :ltn!!dtlt uf di>n, ,j m r f,·· C')).! t'L' ,-'l!'--' hitt \\\\'ili L(· ll,"If'd in)n)pdintt I.\\" "'l--.tl ·,ff Ll" (l\\;t.

Leukocyte telomere length is inversely associated with post-load but not with fasting plasma glucose levels.

PubMed

Khalangot, Mykola; Krasnienkov, Dmytro; Vaiserman, Alexander; Avilov, Ivan; Kovtun, Volodymir; Okhrimenko, Nadia; Koliada, Alexander; Kravchenko, Victor

2017-04-01

Type 2 diabetes mellitus is characterized by shorter leukocyte telomere length, but the relationship between leukocyte telomere length and type 2 diabetes mellitus development is rather questioned. Fasting and post-load glycaemia associated with different types of insulin resistance and their relation with leukocyte telomere length remains unknown. We compared leukocyte telomere length and fasting or post-load glucose levels in persons who do not receive glucose lowering treatment. For 82 randomly selected rural residents of Ukraine, aged 45+, not previously diagnosed with type 2 diabetes mellitus, the WHO oral glucose tolerance test and anthropometric measurements were performed. Leukocyte telomere length was measured by standardized method of quantitative monochrome multiplex polymerase chain reaction in real time. Spearman's or Pearson's rank correlation was used for correlation analysis between fasting plasma glucose or 2-h post-load plasma glucose levels and leukocyte telomere length. Logistical regression models were used to evaluate risks of finding short or long telomeres associated with fasting plasma glucose or 2-h post-load plasma glucose levels. No association of fasting plasma glucose and leukocyte telomere length was revealed, whereas 2-h post-load plasma glucose levels demonstrated a negative correlation ( P < 0.01) with leukocyte telomere length. Waist circumference and systolic blood pressure were negatively related ( P = 0.03) with leukocyte telomere length in men. Oral glucose tolerance test result-based glycemic categories did not show differences between mean leukocyte telomere length in categories of normal fasting plasma glucose and 2-h post-load plasma glucose (NGT, n = 33); diabetes mellitus (DM), n = 18 and impaired fasting glucose/tolerance (IFG/IGT, n = 31) levels. A correlation relationship between leukocyte telomere length and 2-h post-load plasma glucose level in NGT; IFG/IGT and DM groups ( P = 0.027; 0.029 and 0.049, respectively) was revealed; the association between leukocyte telomere length and fasting plasma glucose was confirmed in DM group only ( P = 0.009). Increase of 2-h post-load plasma glucose (but not fasting plasma glucose) level improves the chances of revealing short telomeres: OR 1.52 (95% CI 1.04-2.22), P = 0.03. After the adjustment for age, gender, waist circumference, systolic blood pressure, and fasting plasma glucose, these phenomena remain significant. We conclude that 2-h post-load plasma glucose but not fasting plasma glucose is inversely associated with leukocyte telomere length. Impact statement • Contradictory epidemiologic data have been obtained about the link between the leucocyte telomere length (LTL) and diabetes. Type 2 diabetes (T2D) is likely to be pathophysiologically heterogeneous, but comparison of the association of LTL separately with fasting plasma glucose (FPG) and 2-h post-load plasma glucose (2hPG) levels has not been done before. Thus, the study of LTL changes associated with different types of hyperglycaemia, that largely determine the heterogenity of T2D is important. • In a population-based study of rural Ukrainians, we were the first to demonstrate that the increase of 2hPG (but not FPG) level increases the chances of revealing short telomeres. • The obtained data can help to clarify the relationship between the LTL shortening and different conditions of the insulin resistance (mainly liver resistance in high FPG and mostly muscle and adipose tissue resistance in high 2hPG).

Couplerlib: a metadata-driven library for the integration of multiple models of higher and lower trophic level marine systems with inexact functional group matching

NASA Astrophysics Data System (ADS)

Beecham, Jonathan; Bruggeman, Jorn; Aldridge, John; Mackinson, Steven

2016-03-01

End-to-end modelling is a rapidly developing strategy for modelling in marine systems science and management. However, problems remain in the area of data matching and sub-model compatibility. A mechanism and novel interfacing system (Couplerlib) is presented whereby a physical-biogeochemical model (General Ocean Turbulence Model-European Regional Seas Ecosystem Model, GOTM-ERSEM) that predicts dynamics of the lower trophic level (LTL) organisms in marine ecosystems is coupled to a dynamic ecosystem model (Ecosim), which predicts food-web interactions among higher trophic level (HTL) organisms. Coupling is achieved by means of a bespoke interface, which handles the system incompatibilities between the models and a more generic Couplerlib library, which uses metadata descriptions in extensible mark-up language (XML) to marshal data between groups, paying attention to functional group mappings and compatibility of units between models. In addition, within Couplerlib, models can be coupled across networks by means of socket mechanisms. As a demonstration of this approach, a food-web model (Ecopath with Ecosim, EwE) and a physical-biogeochemical model (GOTM-ERSEM) representing the North Sea ecosystem were joined with Couplerlib. The output from GOTM-ERSEM varies between years, depending on oceanographic and meteorological conditions. Although inter-annual variability was clearly present, there was always the tendency for an annual cycle consisting of a peak of diatoms in spring, followed by (less nutritious) flagellates and dinoflagellates through the summer, resulting in an early summer peak in the mesozooplankton biomass. Pelagic productivity, predicted by the LTL model, was highly seasonal with little winter food for the higher trophic levels. The Ecosim model was originally based on the assumption of constant annual inputs of energy and, consequently, when coupled, pelagic species suffered population losses over the winter months. By contrast, benthic populations were more stable (although the benthic linkage modelled was purely at the detritus level, so this stability reflects the stability of the Ecosim model). The coupled model was used to examine long-term effects of environmental change, and showed the system to be nutrient limited and relatively unaffected by forecast climate change, especially in the benthos. The stability of an Ecosim formulation for large higher tropic level food webs is discussed and it is concluded that this kind of coupled model formulation is better for examining the effects of long-term environmental change than short-term perturbations.

77 FR 73456 - Update to the TR-12 Fuel Related Rate Adjustment Policy (SDDC Fuel Surcharge Policy)

Federal Register 2010, 2011, 2012, 2013, 2014

2012-12-10

... Time Only (OTO) personal property movements, regardless of mode. SDDC will not pay a FRA for any type... less-than-truckload (LTL) and Personal Property (PP) shipments. The percentage of line-haul increment... property movements within the United States. This policy provides the transportation industry, including...

Implicit and Explicit Memory for Affective Passages in Temporal Lobectomy Patients

ERIC Educational Resources Information Center

Burton, Leslie A.; Rabin, Laura; Vardy, Susan Bernstein; Frohlich, Jonathan; Porter, Gwinne Wyatt; Dimitri, Diana; Cofer, Lucas; Labar, Douglas

2008-01-01

Eighteen temporal lobectomy patients (9 left, LTL; 9 right, RTL) were administered four verbal tasks, an Affective Implicit Task, a Neutral Implicit Task, an Affective Explicit Task, and a Neutral Explicit Task. For the Affective and Neutral Implicit Tasks, participants were timed while reading aloud passages with affective or neutral content,…

Assessment of the meat quality of lamb M. longissimus thoracis et lumborum and M. triceps brachii following three different Halal slaughter procedures.

PubMed

Danso, A S; Richardson, R I; Khalid, R

2017-05-01

A total of fifteen male and fifteen female lambs were allocated to three groups of ten animals and subjected to: traditional Halal slaughter without stunning (TNS); slaughter following electric head-only stunning (EHOS) or; post-cut electric head-only stun (PCEHOS) and their meat quality was determined. Instrumental and sensory analyses were carried out on two muscles; M. longissimus thoracis et lumborum (LTL) and M. triceps brachii (TB). Additionally, the effects of sex and muscle type were also assessed. No differences were found among slaughter methods for pH, drip loss and shear force. TB had a higher pHu and was more tender than LTL. Muscles from EHOS and PCEHOS lambs discoloured more quickly than TNS muscles. There were no differences in the measured sensory attributes, with the exception of EHOS meat being tougher than PCEHOS and TNS meat. This study showed that the three slaughter methods had no substantial effect on lamb meat quality. Copyright © 2017 Elsevier Ltd. All rights reserved.

TERT Polymorphism rs2736100-C Is Associated with EGFR Mutation-Positive Non-Small Cell Lung Cancer

PubMed Central

Zheng, Yonglan; Niu, Xiaomin; Weng, Xiaoling; Zhang, Hong; Favus, Murray; Zhang, Lanjun; Jia, Weihua; Zeng, Yixin; Amos, Christopher I; Lu, Shun; Wang, Hui-Yun; Liu, Yun; Liu, Wanqing

2015-01-01

Purpose Epidermal growth factor receptor (EGFR) mutation-positive (EGFRmut+) non-small cell lung cancer (NSCLC) may be a unique orphan disease. Previous studies suggested that the telomerase reverse transcriptase (TERT) gene polymorphism is associated with demographic and clinical features strongly associated with EGFR mutations, e.g. adenocarcinoma histology, never-smoking history and female gender. We aim to test the association between TERT polymorphism and EGFRmut+ NSCLC. Experimental Design We conducted a genetic association study in Chinese NSCLC patients (n=714) and healthy controls (n=2,520), between the rs2736100 polymorphism and EGFRmut+ NSCLC. We further tested the association between the EGFR mutation status and mean leukocyte telomere length (LTL). The potential function of rs2736100 in lung epithelial cells was also explored. Results The rs2736100-C allele was significantly associated with EGFRmut+ NSCLC (OR=1.52, 95%CI=1.28–1.80, p=1.6×10−6) but not EGFRmut− NSCLC (OR=1.07, 95%CI=0.92–1.24, p=0.4). While NSCLC patients as a whole have significantly longer LTL compared to healthy controls (p≤10−13), the EGFRmut+ patients have even longer LTL compared to EGFRmut-patients (p=0.008). Meanwhile, rs2736100 was significantly associated with TERT mRNA expression in both normal and tumor lung tissues. All results remained significant after controlling for age, gender, smoking status and histology (p<0.05 for all tests). Moreover, the rs2736100 DNA sequence has an allele-specific affinity to nuclear proteins extracted from lung epithelial cells, which led to an altered enhancer activity of the sequence in vitro. Conclusion Our study suggests that telomerase and telomere function may be essential for carcinogenesis of EGFRmut+ NSCLC. Further investigation for the underlying mechanism is warranted. PMID:26149460

U.S. EPA, Pesticide Product Label, ALL SEASON SPRAYABLE WEED & FEED, 10/04/1991

EPA Pesticide Factsheets

2011-04-21

... ltifo ~tdt~U4:tl\\. "tl(, ~(\\t ~lt:p'.\\ nlr~Ltl) to ""II" 1u '11(';,\\ etf' ~ur·t~(f. "'ilter '\\ r,t,.,Stl1t \\.or to I,'t'd1.,O')1 at «.;~ lr I"" Ir,£ I',tan r II/I: If<1ter .:ar ... • ...

Receiver Operating Characteristic Curve Analysis of Wechsler Memory Scale-Revised Scores in Epilepsy Surgery Candidates.

ERIC Educational Resources Information Center

Barr, William B.

1997-01-01

Wechsler Memory Scale-Revised (WMS-R) scores were analyzed for 82 epilepsy surgery candidates and used in combination with receiver operating characteristic curves to classify patients with left (LTL) and right (RTL) temporal lobe seizure onset. Results indicate that WMS-R scores used alone or in combination provide relatively poor discrimination…

U.S. EPA, Pesticide Product Label, MYCOTROL ES, 11/13/2008

EPA Pesticide Factsheets

2011-04-21

... rL"plr~iI,'r Ille·l·tillg .\\iII)SI I sl~llldards nfa( kast R-'):'i or Pl)5. Rq)~alCd L'XpOSUI\\' III hit!h l'PllcL'llIr:lliull:' pI" 1l1l .... Ttihl:!I 111"1)IL'II1:-. (:llll';ltl:-'l' alh . ...

Computer-Aided Detection of Rapid, Overt, Airborne, Reconnaissance Data with the Capability of Removing Oceanic Noises

DTIC Science & Technology

2013-12-01

dl--NA’u•-.llw l"\\l;t.l"t, "’’"~r~ll•t• ·•~r•d "’lcottt~ry oaf"!’@ 11\\•ol\\dorwu"’ Mtb! .ctv• titA Mourtd 1Nl..en.ce l’llntell•eR ~ltl4.nftUt!rlc

Report on the Status of Students and Families Who Received Mental Health and Case Management Services at Linkages to Learning Sites, 2013-2014

ERIC Educational Resources Information Center

Wade, Julie; Maina, Nyambura

2016-01-01

Students who received mental health services at a Linkages to Learning (LTL) site showed improvement on some measures of well-being and school engagement, including self-ratings of self-concept and attendance. Families who received case management services showed improvement on multiple areas of self-sufficiency, and large percentages of…

78 FR 59328 - Commercial Driver's License Standards: Definition of Tank Vehicle Used for Determining the...

Federal Register 2010, 2011, 2012, 2013, 2014

2013-09-26

... knowledge (which may be accomplished through self-study) that drivers of tank vehicles will need in order to... commonly move by less than truckload (LTL) carriers. While IBCs may have a capacity of up to 3,000 liters, the sizes more commonly in use range up to 1,000 liters (264 gallons). The guidance published on May...

Effect of a dietary supplementation with linseed oil and selenium to growing rabbits on their productive performances, carcass traits and fresh and cooked meat quality.

PubMed

Matics, Zs; Cullere, M; Szín, M; Gerencsér, Zs; Szabó, A; Fébel, H; Odermatt, M; Radnai, I; Dalle Zotte, A; Szendrő, Zs

2017-08-01

The present experiment tested a dietary supplementation with linseed oil and selenium to growing rabbits. The basal diet (B) contained 3% sunflower oil, while it was substituted with 3% linseed oil in the experimental feed (S). The selenium (Se) content of the two diets was 0.10 vs. 0.46 mg/kg. Rabbits were fed with B diet from the age of 18 days. One group was fed with the B diet until 11 weeks of age (group B), whereas the experimental groups were fed with S diet for 1, 2, 3 or 4 weeks (groups S1, S2, S3 and S4, respectively), before slaughtering (11 weeks of age). Live performance and carcass traits of rabbits, fatty acid (FA) profile and selenium content of their hind leg (HL) and Longissimus thoracis et lumborum (LTL) meat were considered in this study. In addition, the effect of two different cooking methods on the nutritional value of the enriched HL meat was also assessed. The tested dietary supplementation only minimally affected the live performance and carcass traits of rabbits. The S supplementation significantly reduced the Σ n-6 FA and increased the Σ n-3 FA of the HL meat and LTL meat, compared to the B diet (p < 0.001); thus, n-6/n-3 ratio was improved (p < 0.001). In addition, HL meat and LTL meat of S fed rabbits were significantly enriched in Se reaching a twofold increase in both meat cuts (p < 0.01). Therefore, the S supplementation improved the functional value of the rabbit meat. The heat treatment affected cooking loss, Se and vitamin E contents as well as the oxidative status of the HL meat (p < 0.001), with the different cooking methods providing different results. In addition, even if the beneficial C20:5 n-3 and C22:6 n-3 decreased with cooking, the n-6/n-3 ratio remained unaffected. Journal of Animal Physiology and Animal Nutrition © 2016 Blackwell Verlag GmbH.

Coordinating Robot Teams for Disaster Relief

DTIC Science & Technology

2015-05-01

eventually guide vehicles in cooperation with its Operator(s), but in this paper we assume static mission goals, a fixed number of vehicles, and a...is tedious and error prone. Kress-Gazit et al. (2009) instead synthesize an FSA from an LTL specification using a game theory approach (Bloem et al...helping an Operator coordinate a team of vehicles in Disaster Relief. Acknowledgements Thanks to OSD ASD (R&E) for sponsoring this research. The

The Evolution of the Navy Supply Corps and Its Role in Future Operations

DTIC Science & Technology

2013-04-25

AI:IJX~ \\ ’..-, .:no~ -..)(.11. A."ll> l OTill Ot’tlCt. fll>’ M ~ .. \\ftlJ.t&\\ I n tu toon. 1’<\\,PU.,.,Y)Q. XEIJl" Cll ().’\\ "’()Jfr’T{O"\\’’r4..I’ltl Wr...to this inventory loss. Majority of the time it stems from miscommunication along the chain of end user, inventory control points, commercial

Addressing Dynamic Issues of Program Model Checking

NASA Technical Reports Server (NTRS)

Lerda, Flavio; Visser, Willem

2001-01-01

Model checking real programs has recently become an active research area. Programs however exhibit two characteristics that make model checking difficult: the complexity of their state and the dynamic nature of many programs. Here we address both these issues within the context of the Java PathFinder (JPF) model checker. Firstly, we will show how the state of a Java program can be encoded efficiently and how this encoding can be exploited to improve model checking. Next we show how to use symmetry reductions to alleviate some of the problems introduced by the dynamic nature of Java programs. Lastly, we show how distributed model checking of a dynamic program can be achieved, and furthermore, how dynamic partitions of the state space can improve model checking. We support all our findings with results from applying these techniques within the JPF model checker.

Symbolic Computation of Strongly Connected Components Using Saturation

NASA Technical Reports Server (NTRS)

Zhao, Yang; Ciardo, Gianfranco

2010-01-01

Finding strongly connected components (SCCs) in the state-space of discrete-state models is a critical task in formal verification of LTL and fair CTL properties, but the potentially huge number of reachable states and SCCs constitutes a formidable challenge. This paper is concerned with computing the sets of states in SCCs or terminal SCCs of asynchronous systems. Because of its advantages in many applications, we employ saturation on two previously proposed approaches: the Xie-Beerel algorithm and transitive closure. First, saturation speeds up state-space exploration when computing each SCC in the Xie-Beerel algorithm. Then, our main contribution is a novel algorithm to compute the transitive closure using saturation. Experimental results indicate that our improved algorithms achieve a clear speedup over previous algorithms in some cases. With the help of the new transitive closure computation algorithm, up to 10(exp 150) SCCs can be explored within a few seconds.

Program Model Checking: A Practitioner's Guide

NASA Technical Reports Server (NTRS)

Pressburger, Thomas T.; Mansouri-Samani, Masoud; Mehlitz, Peter C.; Pasareanu, Corina S.; Markosian, Lawrence Z.; Penix, John J.; Brat, Guillaume P.; Visser, Willem C.

2008-01-01

Program model checking is a verification technology that uses state-space exploration to evaluate large numbers of potential program executions. Program model checking provides improved coverage over testing by systematically evaluating all possible test inputs and all possible interleavings of threads in a multithreaded system. Model-checking algorithms use several classes of optimizations to reduce the time and memory requirements for analysis, as well as heuristics for meaningful analysis of partial areas of the state space Our goal in this guidebook is to assemble, distill, and demonstrate emerging best practices for applying program model checking. We offer it as a starting point and introduction for those who want to apply model checking to software verification and validation. The guidebook will not discuss any specific tool in great detail, but we provide references for specific tools.

Verifying Multi-Agent Systems via Unbounded Model Checking

NASA Technical Reports Server (NTRS)

Kacprzak, M.; Lomuscio, A.; Lasica, T.; Penczek, W.; Szreter, M.

2004-01-01

We present an approach to the problem of verification of epistemic properties in multi-agent systems by means of symbolic model checking. In particular, it is shown how to extend the technique of unbounded model checking from a purely temporal setting to a temporal-epistemic one. In order to achieve this, we base our discussion on interpreted systems semantics, a popular semantics used in multi-agent systems literature. We give details of the technique and show how it can be applied to the well known train, gate and controller problem. Keywords: model checking, unbounded model checking, multi-agent systems

Toward improved design of check dam systems: A case study in the Loess Plateau, China

NASA Astrophysics Data System (ADS)

Pal, Debasish; Galelli, Stefano; Tang, Honglei; Ran, Qihua

2018-04-01

Check dams are one of the most common strategies for controlling sediment transport in erosion prone areas, along with soil and water conservation measures. However, existing mathematical models that simulate sediment production and delivery are often unable to simulate how the storage capacity of check dams varies with time. To explicitly account for this process-and to support the design of check dam systems-we developed a modelling framework consisting of two components, namely (1) the spatially distributed Soil Erosion and Sediment Delivery Model (WaTEM/SEDEM), and (2) a network-based model of check dam storage dynamics. The two models are run sequentially, with the second model receiving the initial sediment input to check dams from WaTEM/SEDEM. The framework is first applied to Shejiagou catchment, a 4.26 km2 area located in the Loess Plateau, China, where we study the effect of the existing check dam system on sediment dynamics. Results show that the deployment of check dams altered significantly the sediment delivery ratio of the catchment. Furthermore, the network-based model reveals a large variability in the life expectancy of check dams and abrupt changes in their filling rates. The application of the framework to six alternative check dam deployment scenarios is then used to illustrate its usefulness for planning purposes, and to derive some insights on the effect of key decision variables, such as the number, size, and site location of check dams. Simulation results suggest that better performance-in terms of life expectancy and sediment delivery ratio-could have been achieved with an alternative deployment strategy.

Implementing Model-Check for Employee and Management Satisfaction

NASA Technical Reports Server (NTRS)

Jones, Corey; LaPha, Steven

2013-01-01

This presentation will discuss methods to which ModelCheck can be implemented to not only improve model quality, but also satisfy both employees and management through different sets of quality checks. This approach allows a standard set of modeling practices to be upheld throughout a company, with minimal interaction required by the end user. The presenter will demonstrate how to create multiple ModelCheck standards, preventing users from evading the system, and how it can improve the quality of drawings and models.

Finding Feasible Abstract Counter-Examples

NASA Technical Reports Server (NTRS)

Pasareanu, Corina S.; Dwyer, Matthew B.; Visser, Willem; Clancy, Daniel (Technical Monitor)

2002-01-01

A strength of model checking is its ability to automate the detection of subtle system errors and produce traces that exhibit those errors. Given the high computational cost of model checking most researchers advocate the use of aggressive property-preserving abstractions. Unfortunately, the more aggressively a system is abstracted the more infeasible behavior it will have. Thus, while abstraction enables efficient model checking it also threatens the usefulness of model checking as a defect detection tool, since it may be difficult to determine whether a counter-example is feasible and hence worth developer time to analyze. We have explored several strategies for addressing this problem by extending an explicit-state model checker, Java PathFinder (JPF), to search for and analyze counter-examples in the presence of abstractions. We demonstrate that these techniques effectively preserve the defect detection ability of model checking in the presence of aggressive abstraction by applying them to check properties of several abstracted multi-threaded Java programs. These new capabilities are not specific to JPF and can be easily adapted to other model checking frameworks; we describe how this was done for the Bandera toolset.

12 CFR Appendix C to Part 229 - Model Availability Policy Disclosures, Clauses, and Notices; Model Substitute Check Policy...

Code of Federal Regulations, 2014 CFR

2014-01-01

... processing regions)]. If you make the deposit in person to one of our employees, funds from the following... in different states or check processing regions)]. If you make the deposit in person to one of our...] Substitute Checks and Your Rights What Is a Substitute Check? To make check processing faster, federal law...

Effects of dietary oil blend on fatty acid composition, oxidative stability and physicochemical properties of Longissimus thoracis et lumborum muscle in goats.

PubMed

Adeyemi, Kazeem Dauda; Sabow, Azad Behnan; Abubakar, Ahmed; Samsudin, Anjas Asmara; Sazili, Awis Qurni

2016-11-01

This study examined the effects of dietary blend of 80% canola oil and 20% palm oil (BCPO) on the physicochemical properties, antioxidant status, oxidative stability and fatty acid composition of Longissimus thoracis et lumborum (LTL) muscle from goats during chill storage. Over a 14-week feeding trial, 24 Boer bucks were randomly assigned to and supplemented with diets containing 0, 4 or 8% BCPO on a dry matter basis, slaughtered and the LTL was subjected to a 7 day chill storage. Neither diet nor post mortem ageing influenced (P > 0.05) antioxidant enzyme activities, chemical composition and cholesterol. Diet had no effect on the carbonyl content, free thiol content, water-holding capacity, tenderness, pH and glycogen. Oil-supplemented goats had higher (P < 0.05) C18:1 trans-11, C18:3n-3 and C20:5n-3, carotenoid, tocopherol and redness, and lower thiobarbituric acid reactive substances values than the control goats. Post mortem ageing decreased (P < 0.05) shear force and oxidative stability of chevon. No significant (P > 0.05) changes were found in the proportion of individual fatty acids throughout storage. Total polyunsaturated fatty acids (PUFA) decreased while total saturated fatty acids increased as storage progressed. Dietary BCPO enhanced n-3 PUFA without compromising the quality attributes of chevon. © 2016 Japanese Society of Animal Science.

Application of conditional moment tests to model checking for generalized linear models.

PubMed

Pan, Wei

2002-06-01

Generalized linear models (GLMs) are increasingly being used in daily data analysis. However, model checking for GLMs with correlated discrete response data remains difficult. In this paper, through a case study on marginal logistic regression using a real data set, we illustrate the flexibility and effectiveness of using conditional moment tests (CMTs), along with other graphical methods, to do model checking for generalized estimation equation (GEE) analyses. Although CMTs provide an array of powerful diagnostic tests for model checking, they were originally proposed in the econometrics literature and, to our knowledge, have never been applied to GEE analyses. CMTs cover many existing tests, including the (generalized) score test for an omitted covariate, as special cases. In summary, we believe that CMTs provide a class of useful model checking tools.

Take the Reins on Model Quality with ModelCHECK and Gatekeeper

NASA Technical Reports Server (NTRS)

Jones, Corey

2012-01-01

Model quality and consistency has been an issue for us due to the diverse experience level and imaginative modeling techniques of our users. Fortunately, setting up ModelCHECK and Gatekeeper to enforce our best practices has helped greatly, but it wasn't easy. There were many challenges associated with setting up ModelCHECK and Gatekeeper including: limited documentation, restrictions within ModelCHECK, and resistance from end users. However, we consider ours a success story. In this presentation we will describe how we overcame these obstacles and present some of the details of how we configured them to work for us.

Summary of ARI Research on Remotely Monitored Sensors

DTIC Science & Technology

1980-07-01

I NAVY PFRSONNEL R AND 0 CENTER/ I US ARMY AVN ENbINEERING FLIGHT ACTIVIIY ATTN8 SAVTE- TD SoFc OF NAVAL RESEARCH PERSONNEL AND TRAINING RESEARCH...LABS ATTN: LTL- TD -S I USA MORILITY EWUIPMENT R AND 0 COMO ATTNS ODMUE-TO I NIGHT VISION LAH ATTN: UHSEL-NV-SUU I USA TRAINING BUAHD I USA HUMAN...I PURDUE UNIV DLPT OF PSYCMOLOGICAL SCIE.NCES 1 05A MOHILITY EWI,1PMENT w AND 0 LUMMANL) ATTNt URDME-1rG IHQ . USA MDW ATTN; ANPE-vE It D A US ARMY

12 CFR Appendix C to Part 229 - Model Availability Policy Disclosures, Clauses, and Notices; Model Substitute Check Policy...

Code of Federal Regulations, 2010 CFR

2010-01-01

... 12 Banks and Banking 3 2010-01-01 2010-01-01 false Model Availability Policy Disclosures, Clauses, and Notices; Model Substitute Check Policy Disclosure and Notices C Appendix C to Part 229 Banks and... OF FUNDS AND COLLECTION OF CHECKS (REGULATION CC) Pt. 229, App. C Appendix C to Part 229—Model...

The influence of social anxiety on the body checking behaviors of female college students.

PubMed

White, Emily K; Warren, Cortney S

2014-09-01

Social anxiety and eating pathology frequently co-occur. However, there is limited research examining the relationship between anxiety and body checking, aside from one study in which social physique anxiety partially mediated the relationship between body checking cognitions and body checking behavior (Haase, Mountford, & Waller, 2007). In an independent sample of 567 college women, we tested the fit of Haase and colleagues' foundational model but did not find evidence of mediation. Thus we tested the fit of an expanded path model that included eating pathology and clinical impairment. In the best-fitting path model (CFI=.991; RMSEA=.083) eating pathology and social physique anxiety positively predicted body checking, and body checking positively predicted clinical impairment. Therefore, women who endorse social physique anxiety may be more likely to engage in body checking behaviors and experience impaired psychosocial functioning. Published by Elsevier Ltd.

12 CFR Appendix C to Part 229 - Model Availability Policy Disclosures, Clauses, and Notices; Model Substitute Check Policy...

Code of Federal Regulations, 2012 CFR

2012-01-01

... in different states or check processing regions)]. If you make the deposit in person to one of our... processing regions)]. If you make the deposit in person to one of our employees, funds from the following... Your Rights What Is a Substitute Check? To make check processing faster, federal law permits banks to...

12 CFR Appendix C to Part 229 - Model Availability Policy Disclosures, Clauses, and Notices; Model Substitute Check Policy...

Code of Federal Regulations, 2011 CFR

2011-01-01

... in different states or check processing regions)]. If you make the deposit in person to one of our... processing regions)]. If you make the deposit in person to one of our employees, funds from the following... Your Rights What Is a Substitute Check? To make check processing faster, federal law permits banks to...

12 CFR Appendix C to Part 229 - Model Availability Policy Disclosures, Clauses, and Notices; Model Substitute Check Policy...

Code of Federal Regulations, 2013 CFR

2013-01-01

... in different states or check processing regions)]. If you make the deposit in person to one of our... processing regions)]. If you make the deposit in person to one of our employees, funds from the following... Your Rights What Is a Substitute Check? To make check processing faster, federal law permits banks to...

Determination of MLC model parameters for Monaco using commercial diode arrays.

PubMed

Kinsella, Paul; Shields, Laura; McCavana, Patrick; McClean, Brendan; Langan, Brian

2016-07-08

Multileaf collimators (MLCs) need to be characterized accurately in treatment planning systems to facilitate accurate intensity-modulated radiation therapy (IMRT) and volumetric-modulated arc therapy (VMAT). The aim of this study was to examine the use of MapCHECK 2 and ArcCHECK diode arrays for optimizing MLC parameters in Monaco X-ray voxel Monte Carlo (XVMC) dose calculation algorithm. A series of radiation test beams designed to evaluate MLC model parameters were delivered to MapCHECK 2, ArcCHECK, and EBT3 Gafchromic film for comparison. Initial comparison of the calculated and ArcCHECK-measured dose distributions revealed it was unclear how to change the MLC parameters to gain agreement. This ambiguity arose due to an insufficient sampling of the test field dose distributions and unexpected discrepancies in the open parts of some test fields. Consequently, the XVMC MLC parameters were optimized based on MapCHECK 2 measurements. Gafchromic EBT3 film was used to verify the accuracy of MapCHECK 2 measured dose distributions. It was found that adjustment of the MLC parameters from their default values resulted in improved global gamma analysis pass rates for MapCHECK 2 measurements versus calculated dose. The lowest pass rate of any MLC-modulated test beam improved from 68.5% to 93.5% with 3% and 2 mm gamma criteria. Given the close agreement of the optimized model to both MapCHECK 2 and film, the optimized model was used as a benchmark to highlight the relatively large discrepancies in some of the test field dose distributions found with ArcCHECK. Comparison between the optimized model-calculated dose and ArcCHECK-measured dose resulted in global gamma pass rates which ranged from 70.0%-97.9% for gamma criteria of 3% and 2 mm. The simple square fields yielded high pass rates. The lower gamma pass rates were attributed to the ArcCHECK overestimating the dose in-field for the rectangular test fields whose long axis was parallel to the long axis of the ArcCHECK. Considering ArcCHECK measurement issues and the lower gamma pass rates for the MLC-modulated test beams, it was concluded that MapCHECK 2 was a more suitable detector than ArcCHECK for the optimization process. © 2016 The Authors

Propel: Tools and Methods for Practical Source Code Model Checking

NASA Technical Reports Server (NTRS)

Mansouri-Samani, Massoud; Mehlitz, Peter; Markosian, Lawrence; OMalley, Owen; Martin, Dale; Moore, Lantz; Penix, John; Visser, Willem

2003-01-01

The work reported here is an overview and snapshot of a project to develop practical model checking tools for in-the-loop verification of NASA s mission-critical, multithreaded programs in Java and C++. Our strategy is to develop and evaluate both a design concept that enables the application of model checking technology to C++ and Java, and a model checking toolset for C++ and Java. The design concept and the associated model checking toolset is called Propel. It builds upon the Java PathFinder (JPF) tool, an explicit state model checker for Java applications developed by the Automated Software Engineering group at NASA Ames Research Center. The design concept that we are developing is Design for Verification (D4V). This is an adaption of existing best design practices that has the desired side-effect of enhancing verifiability by improving modularity and decreasing accidental complexity. D4V, we believe, enhances the applicability of a variety of V&V approaches; we are developing the concept in the context of model checking. The model checking toolset, Propel, is based on extending JPF to handle C++. Our principal tasks in developing the toolset are to build a translator from C++ to Java, productize JPF, and evaluate the toolset in the context of D4V. Through all these tasks we are testing Propel capabilities on customer applications.

Genotype and sex effects on carcass and meat quality of suckling kids protected by the PGI "Cabrito de Barroso".

PubMed

Santos, V A C; Silva, A O; Cardoso, J V F; Silvestre, A J D; Silva, S R; Martins, C; Azevedo, J M T

2007-04-01

Carcass composition and meat quality traits were evaluated in 55 suckling kids (27 males and 28 females) from Serrana (S), Bravia (B) and Serrana×Bravia (S×B) crossbred genotypes. Kids were slaughtered at 8-11kg of live weight according to "Cabrito de Barroso-PGI" specifications and carcasses' left sides were totally dissected. Dressing percentage (based on ELW) did not vary between genotypes and sexes. Genotype B carcasses have better conformation, expressed in higher compactness index and muscle/bone ratio. Sex had no effect on the composition of dissected carcass but females deposited more internal fat than males. S genotype had significantly less muscle content and higher dissectible fat compared to B and S×B genotypes, suggesting differences in maturity stages. The carcass' bone content (20.4-21.4%) did not differ significantly between genotypes. The longissimus thoracis et lumborum (LTL) and gluteobiceps (GB) muscles were used for meat quality determinations. Genotype had a significant effect on meat traits and fatty acid composition of the analysed muscles: B genotype and LTL muscle showed lower final pH, S×B genotype had darker and more red muscles, GB muscle had a higher shear force value and lower collagen solubility. Few sex effects were observed on meat quality traits as well as on fatty acid composition. Average percentage of desirable fatty acids in kids was superior to 60% with male S genotype displaying a lower value. Genotypes B and B×S, males and GB muscle had more favorable PUFA:SFA ratios.

The effect of post-exsanguination infusion on the composition, exudation, color and post-mortem metabolic changes in lamb.

PubMed

Farouk, M M; Price, J F

1994-01-01

Twenty-four lamb carcasses were assigned to three treatment groups: (1) control (Ctr), (2) infused with 10% (vol/wt) of a tenderizing blend (NCa), and (3) NCa plus 0·015 m CaCl(2) (WCa). Results indicated that the infused carcass solution was retained in the following order: shoulder > lion > leg. Infusion had no effect (P > 0·05) on drip and cooking losses in refrigerated samples. Samples frozen and then thawed from infused carcasses had greater thaw drip (P < 0·05) and cooking losses (P < 0·01) than control samples. The amounts of drip and cooking losses were in the order: WCa > NCa > Ctr. Frozen storage preserved the red color but lowered the lightness and yellowness of ovine muscles; the opposite effect was observed following refrigerated storage. Infused samples were lighter and yellower than control in both fresh and frozen samples (P < 0·01). WCa had less red color (P < 0·01) than NCa and Ctr at all times and storage conditions. Infusion lowered (P < 0·05) the temperature of carcasses over the first 3 h postmortem (pm) compared with Ctr. The rate of glycolysis was higher in infraspinatus (IS) than in longissimus thoracis et lumborum muscle (LTL or longissimus). In both IS and LTL, glycolysis was completed within the first 6 h postmortem in NCa, whereas in Ctr and WCa, it took 12-24 h for glycolysis to be completed. The rate of glycolysis was in the order: NCa > WCa > Ctr. Copyright © 1994. Published by Elsevier Ltd.

Assessment of lamb carcass composition from live animal measurement of bioelectrical impedance or ultrasonic tissue depths.

PubMed

Berg, E P; Neary, M K; Forrest, J C; Thomas, D L; Kauffman, R G

1996-11-01

Market weight lambs, average weight 52.5 kg (+/-6.1), were used to evaluate nontraditional live animal measurements as predictors of carcass composition. The sample population (n = 106) represented U.S. market lambs and transcended geographic location, breed, carcass weight, yield grade, and production system. Realtime ultrasonic (RU) measurements and bioelectrical impedance analysis (BIA) were used for development and evaluation of prediction equations for % boneless, closely trimmed primal cuts (BCTPC), weight or % of dissected lean tissue (TDL), and chemically derived weight or % fat-free lean (FFL). Longitudinal ultrasonic images were obtained parallel to the longissimus thoracis et lumborum (LTL), positioning the last costae in the center of the transducer head. Images were saved and fat and LTL depths were derived from printed images of the ultrasonic scans. Bioelectrical impedance analysis was administered via a four-terminal impedance plethysmograph operating at 800 microA at 50 kHz. Impedance measurements of whole-body resistance and reactance were recorded. Prediction equations including common linear measurements of live weight, heart girth, hindsaddle length, and shoulder height were also evaluated. All measurements were taken just before slaughter. Bioelectrical impedance measurements (as compared to RU and linear measurements) provided equations for %BCTPC, TDL, %TDL, FFL and %FFL with the highest R2 and lowest root mean square error. Even though BIA provided the best equations of the three methodologies tested, prediction of proportional yield (%BCTPC, %TDL, and %FFL) was marginal (R2 = .296, .551, and .551, respectively). Equations combining BIA, RU, and linear measurements greatly improved equations for prediction of proportional lean yield.

Program Model Checking as a New Trend

NASA Technical Reports Server (NTRS)

Havelund, Klaus; Visser, Willem; Clancy, Daniel (Technical Monitor)

2002-01-01

This paper introduces a special section of STTT (International Journal on Software Tools for Technology Transfer) containing a selection of papers that were presented at the 7th International SPIN workshop, Stanford, August 30 - September 1, 2000. The workshop was named SPIN Model Checking and Software Verification, with an emphasis on model checking of programs. The paper outlines the motivation for stressing software verification, rather than only design and model verification, by presenting the work done in the Automated Software Engineering group at NASA Ames Research Center within the last 5 years. This includes work in software model checking, testing like technologies and static analysis.

UTP and Temporal Logic Model Checking

NASA Astrophysics Data System (ADS)

Anderson, Hugh; Ciobanu, Gabriel; Freitas, Leo

In this paper we give an additional perspective to the formal verification of programs through temporal logic model checking, which uses Hoare and He Unifying Theories of Programming (UTP). Our perspective emphasizes the use of UTP designs, an alphabetised relational calculus expressed as a pre/post condition pair of relations, to verify state or temporal assertions about programs. The temporal model checking relation is derived from a satisfaction relation between the model and its properties. The contribution of this paper is that it shows a UTP perspective to temporal logic model checking. The approach includes the notion of efficiency found in traditional model checkers, which reduced a state explosion problem through the use of efficient data structures

75 FR 28480 - Airworthiness Directives; Airbus Model A300 Series Airplanes; Model A300 B4-600, B4-600R, F4-600R...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-05-21

... pressurise the hydraulic reservoirs, due to leakage of the Crissair reservoir air pressurisation check valves. * * * The leakage of the check valves was caused by an incorrect spring material. The affected Crissair check valves * * * were then replaced with improved check valves P/N [part number] 2S2794-1 * * *. More...

Assessment of check-dam groundwater recharge with water-balance calculations

NASA Astrophysics Data System (ADS)

Djuma, Hakan; Bruggeman, Adriana; Camera, Corrado; Eliades, Marinos

2017-04-01

Studies on the enhancement of groundwater recharge by check-dams in arid and semi-arid environments mainly focus on deriving water infiltration rates from the check-dam ponding areas. This is usually achieved by applying simple water balance models, more advanced models (e.g., two dimensional groundwater models) and field tests (e.g., infiltrometer test or soil pit tests). Recharge behind the check-dam can be affected by the built-up of sediment as a result of erosion in the upstream watershed area. This natural process can increase the uncertainty in the estimates of the recharged water volume, especially for water balance calculations. Few water balance field studies of individual check-dams have been presented in the literature and none of them presented associated uncertainties of their estimates. The objectives of this study are i) to assess the effect of a check-dam on groundwater recharge from an ephemeral river; and ii) to assess annual sedimentation at the check-dam during a 4-year period. The study was conducted on a check-dam in the semi-arid island of Cyprus. Field campaigns were carried out to measure water flow, water depth and check-dam topography in order to establish check-dam water height, volume, evaporation, outflow and recharge relations. Topographic surveys were repeated at the end of consecutive hydrological years to estimate the sediment built up in the reservoir area of the check dam. Also, sediment samples were collected from the check-dam reservoir area for bulk-density analyses. To quantify the groundwater recharge, a water balance model was applied at two locations: at the check-dam and corresponding reservoir area, and at a 4-km stretch of the river bed without check-dam. Results showed that a check-dam with a storage capacity of 25,000 m3 was able to recharge to the aquifer, in four years, a total of 12 million m3 out of the 42 million m3 of measured (or modelled) streamflow. Recharge from the analyzed 4-km long river section without check-dam was estimated to be 1 million m3. Upper and lower limits of prediction intervals were computed to assess the uncertainties of the results. The model was rerun with these values and resulted in recharge values of 0.4 m3 as lower and 38 million m3 as upper limit. The sediment survey in the check-dam reservoir area showed that the reservoir area was filled with 2,000 to 3,000 tons of sediment after one rainfall season. This amount of sediment corresponds to 0.2 to 2 t h-1 y-1 sediment yield at the watershed level and reduces the check-dam storage capacity by approximately 10%. Results indicate that check-dams are valuable structures for increasing groundwater resources, but special attention should be given to soil erosion occurring in the upstream area and the resulting sediment built-up in the check-dam reservoir area. This study has received funding from the EU FP7 RECARE Project (GA 603498)

Efficient model checking of network authentication protocol based on SPIN

NASA Astrophysics Data System (ADS)

Tan, Zhi-hua; Zhang, Da-fang; Miao, Li; Zhao, Dan

2013-03-01

Model checking is a very useful technique for verifying the network authentication protocols. In order to improve the efficiency of modeling and verification on the protocols with the model checking technology, this paper first proposes a universal formalization description method of the protocol. Combined with the model checker SPIN, the method can expediently verify the properties of the protocol. By some modeling simplified strategies, this paper can model several protocols efficiently, and reduce the states space of the model. Compared with the previous literature, this paper achieves higher degree of automation, and better efficiency of verification. Finally based on the method described in the paper, we model and verify the Privacy and Key Management (PKM) authentication protocol. The experimental results show that the method of model checking is effective, which is useful for the other authentication protocols.

An Integrated Environment for Efficient Formal Design and Verification

NASA Technical Reports Server (NTRS)

1998-01-01

The general goal of this project was to improve the practicality of formal methods by combining techniques from model checking and theorem proving. At the time the project was proposed, the model checking and theorem proving communities were applying different tools to similar problems, but there was not much cross-fertilization. This project involved a group from SRI that had substantial experience in the development and application of theorem-proving technology, and a group at Stanford that specialized in model checking techniques. Now, over five years after the proposal was submitted, there are many research groups working on combining theorem-proving and model checking techniques, and much more communication between the model checking and theorem proving research communities. This project contributed significantly to this research trend. The research work under this project covered a variety of topics: new theory and algorithms; prototype tools; verification methodology; and applications to problems in particular domains.

A voice-actuated wind tunnel model leak checking system

NASA Technical Reports Server (NTRS)

Larson, William E.

1989-01-01

A computer program has been developed that improves the efficiency of wind tunnel model leak checking. The program uses a voice recognition unit to relay a technician's commands to the computer. The computer, after receiving a command, can respond to the technician via a voice response unit. Information about the model pressure orifice being checked is displayed on a gas-plasma terminal. On command, the program records up to 30 seconds of pressure data. After the recording is complete, the raw data and a straight line fit of the data are plotted on the terminal. This allows the technician to make a decision on the integrity of the orifice being checked. All results of the leak check program are stored in a database file that can be listed on the line printer for record keeping purposes or displayed on the terminal to help the technician find unchecked orifices. This program allows one technician to check a model for leaks instead of the two or three previously required.

Use of posterior predictive checks as an inferential tool for investigating individual heterogeneity in animal population vital rates

PubMed Central

Chambert, Thierry; Rotella, Jay J; Higgs, Megan D

2014-01-01

The investigation of individual heterogeneity in vital rates has recently received growing attention among population ecologists. Individual heterogeneity in wild animal populations has been accounted for and quantified by including individually varying effects in models for mark–recapture data, but the real need for underlying individual effects to account for observed levels of individual variation has recently been questioned by the work of Tuljapurkar et al. (Ecology Letters, 12, 93, 2009) on dynamic heterogeneity. Model-selection approaches based on information criteria or Bayes factors have been used to address this question. Here, we suggest that, in addition to model-selection, model-checking methods can provide additional important insights to tackle this issue, as they allow one to evaluate a model's misfit in terms of ecologically meaningful measures. Specifically, we propose the use of posterior predictive checks to explicitly assess discrepancies between a model and the data, and we explain how to incorporate model checking into the inferential process used to assess the practical implications of ignoring individual heterogeneity. Posterior predictive checking is a straightforward and flexible approach for performing model checks in a Bayesian framework that is based on comparisons of observed data to model-generated replications of the data, where parameter uncertainty is incorporated through use of the posterior distribution. If discrepancy measures are chosen carefully and are relevant to the scientific context, posterior predictive checks can provide important information allowing for more efficient model refinement. We illustrate this approach using analyses of vital rates with long-term mark–recapture data for Weddell seals and emphasize its utility for identifying shortfalls or successes of a model at representing a biological process or pattern of interest. We show how posterior predictive checks can be used to strengthen inferences in ecological studies. We demonstrate the application of this method on analyses dealing with the question of individual reproductive heterogeneity in a population of Antarctic pinnipeds. PMID:24834335

A Novel Method to Verify Multilevel Computational Models of Biological Systems Using Multiscale Spatio-Temporal Meta Model Checking

PubMed Central

Gilbert, David

2016-01-01

Insights gained from multilevel computational models of biological systems can be translated into real-life applications only if the model correctness has been verified first. One of the most frequently employed in silico techniques for computational model verification is model checking. Traditional model checking approaches only consider the evolution of numeric values, such as concentrations, over time and are appropriate for computational models of small scale systems (e.g. intracellular networks). However for gaining a systems level understanding of how biological organisms function it is essential to consider more complex large scale biological systems (e.g. organs). Verifying computational models of such systems requires capturing both how numeric values and properties of (emergent) spatial structures (e.g. area of multicellular population) change over time and across multiple levels of organization, which are not considered by existing model checking approaches. To address this limitation we have developed a novel approximate probabilistic multiscale spatio-temporal meta model checking methodology for verifying multilevel computational models relative to specifications describing the desired/expected system behaviour. The methodology is generic and supports computational models encoded using various high-level modelling formalisms because it is defined relative to time series data and not the models used to generate it. In addition, the methodology can be automatically adapted to case study specific types of spatial structures and properties using the spatio-temporal meta model checking concept. To automate the computational model verification process we have implemented the model checking approach in the software tool Mule (http://mule.modelchecking.org). Its applicability is illustrated against four systems biology computational models previously published in the literature encoding the rat cardiovascular system dynamics, the uterine contractions of labour, the Xenopus laevis cell cycle and the acute inflammation of the gut and lung. Our methodology and software will enable computational biologists to efficiently develop reliable multilevel computational models of biological systems. PMID:27187178

A Novel Method to Verify Multilevel Computational Models of Biological Systems Using Multiscale Spatio-Temporal Meta Model Checking.

PubMed

Pârvu, Ovidiu; Gilbert, David

2016-01-01

Insights gained from multilevel computational models of biological systems can be translated into real-life applications only if the model correctness has been verified first. One of the most frequently employed in silico techniques for computational model verification is model checking. Traditional model checking approaches only consider the evolution of numeric values, such as concentrations, over time and are appropriate for computational models of small scale systems (e.g. intracellular networks). However for gaining a systems level understanding of how biological organisms function it is essential to consider more complex large scale biological systems (e.g. organs). Verifying computational models of such systems requires capturing both how numeric values and properties of (emergent) spatial structures (e.g. area of multicellular population) change over time and across multiple levels of organization, which are not considered by existing model checking approaches. To address this limitation we have developed a novel approximate probabilistic multiscale spatio-temporal meta model checking methodology for verifying multilevel computational models relative to specifications describing the desired/expected system behaviour. The methodology is generic and supports computational models encoded using various high-level modelling formalisms because it is defined relative to time series data and not the models used to generate it. In addition, the methodology can be automatically adapted to case study specific types of spatial structures and properties using the spatio-temporal meta model checking concept. To automate the computational model verification process we have implemented the model checking approach in the software tool Mule (http://mule.modelchecking.org). Its applicability is illustrated against four systems biology computational models previously published in the literature encoding the rat cardiovascular system dynamics, the uterine contractions of labour, the Xenopus laevis cell cycle and the acute inflammation of the gut and lung. Our methodology and software will enable computational biologists to efficiently develop reliable multilevel computational models of biological systems.

Model Checking Temporal Logic Formulas Using Sticker Automata

PubMed Central

Feng, Changwei; Wu, Huanmei

2017-01-01

As an important complex problem, the temporal logic model checking problem is still far from being fully resolved under the circumstance of DNA computing, especially Computation Tree Logic (CTL), Interval Temporal Logic (ITL), and Projection Temporal Logic (PTL), because there is still a lack of approaches for DNA model checking. To address this challenge, a model checking method is proposed for checking the basic formulas in the above three temporal logic types with DNA molecules. First, one-type single-stranded DNA molecules are employed to encode the Finite State Automaton (FSA) model of the given basic formula so that a sticker automaton is obtained. On the other hand, other single-stranded DNA molecules are employed to encode the given system model so that the input strings of the sticker automaton are obtained. Next, a series of biochemical reactions are conducted between the above two types of single-stranded DNA molecules. It can then be decided whether the system satisfies the formula or not. As a result, we have developed a DNA-based approach for checking all the basic formulas of CTL, ITL, and PTL. The simulated results demonstrate the effectiveness of the new method. PMID:29119114

Foundations of the Bandera Abstraction Tools

NASA Technical Reports Server (NTRS)

Hatcliff, John; Dwyer, Matthew B.; Pasareanu, Corina S.; Robby

2003-01-01

Current research is demonstrating that model-checking and other forms of automated finite-state verification can be effective for checking properties of software systems. Due to the exponential costs associated with model-checking, multiple forms of abstraction are often necessary to obtain system models that are tractable for automated checking. The Bandera Tool Set provides multiple forms of automated support for compiling concurrent Java software systems to models that can be supplied to several different model-checking tools. In this paper, we describe the foundations of Bandera's data abstraction mechanism which is used to reduce the cardinality (and the program's state-space) of data domains in software to be model-checked. From a technical standpoint, the form of data abstraction used in Bandera is simple, and it is based on classical presentations of abstract interpretation. We describe the mechanisms that Bandera provides for declaring abstractions, for attaching abstractions to programs, and for generating abstracted programs and properties. The contributions of this work are the design and implementation of various forms of tool support required for effective application of data abstraction to software components written in a programming language like Java which has a rich set of linguistic features.

Full implementation of a distributed hydrological model based on check dam trapped sediment volumes

NASA Astrophysics Data System (ADS)

Bussi, Gianbattista; Francés, Félix

2014-05-01

Lack of hydrometeorological data is one of the most compelling limitations to the implementation of distributed environmental models. Mediterranean catchments, in particular, are characterised by high spatial variability of meteorological phenomena and soil characteristics, which may prevents from transferring model calibrations from a fully gauged catchment to a totally o partially ungauged one. For this reason, new sources of data are required in order to extend the use of distributed models to non-monitored or low-monitored areas. An important source of information regarding the hydrological and sediment cycle is represented by sediment deposits accumulated at the bottom of reservoirs. Since the 60s, reservoir sedimentation volumes were used as proxy data for the estimation of inter-annual total sediment yield rates, or, in more recent years, as a reference measure of the sediment transport for sediment model calibration and validation. Nevertheless, the possibility of using such data for constraining the calibration of a hydrological model has not been exhaustively investigated so far. In this study, the use of nine check dam reservoir sedimentation volumes for hydrological and sedimentological model calibration and spatio-temporal validation was examined. Check dams are common structures in Mediterranean areas, and are a potential source of spatially distributed information regarding both hydrological and sediment cycle. In this case-study, the TETIS hydrological and sediment model was implemented in a medium-size Mediterranean catchment (Rambla del Poyo, Spain) by taking advantage of sediment deposits accumulated behind the check dams located in the catchment headwaters. Reservoir trap efficiency was taken into account by coupling the TETIS model with a pond trap efficiency model. The model was calibrated by adjusting some of its parameters in order to reproduce the total sediment volume accumulated behind a check dam. Then, the model was spatially validated by obtaining the simulated sedimentation volume at the other eight check dams and comparing it to the observed sedimentation volumes. Lastly, the simulated water discharge at the catchment outlet was compared with observed water discharge records in order to check the hydrological sub-model behaviour. Model results provided highly valuable information concerning the spatial distribution of soil erosion and sediment transport. Spatial validation of the sediment sub-model provided very good results at seven check dams out of nine. This study shows that check dams can be a useful tool also for constraining hydrological model calibration, as model results agree with water discharge observations. In fact, the hydrological model validation at a downstream water flow gauge obtained a Nash-Sutcliffe efficiency of 0.8. This technique is applicable to all catchments with presence of check dams, and only requires rainfall and temperature data and soil characteristics maps.

A Determination of Eligibility to the National Register of Historic Places for Select Historic Properties Along the Souris River in North Dakota

DTIC Science & Technology

1989-08-01

Company Historic District," 1985. "Historic Resources of Hardin, Montana," :984. "Silver Bow Brewery Malt House," 1982. "Silver Bow County Poor Farm...34i QQL-- Q ..i FEATURE TYPE CULTURAL MATERIAL ’iii Site Type -0,- Cm Scatter , , Bone 0 Chimney %.Z Ceramics tA Context .Q, Depression 1 Charcoal i...Sec , QQQ i, QQ . Q, ,LTL, L- Twp R ,.. , Sec ,., QQO 1- QQ’ L- Q’ ’ FEATURE TYPE CULTURAL MATERIAL &. Site Type m, Cm Scatter ,.Z, Bone Chimney

Towards Symbolic Model Checking for Multi-Agent Systems via OBDDs

NASA Technical Reports Server (NTRS)

Raimondi, Franco; Lomunscio, Alessio

2004-01-01

We present an algorithm for model checking temporal-epistemic properties of multi-agent systems, expressed in the formalism of interpreted systems. We first introduce a technique for the translation of interpreted systems into boolean formulae, and then present a model-checking algorithm based on this translation. The algorithm is based on OBDD's, as they offer a compact and efficient representation for boolean formulae.

Compositional schedulability analysis of real-time actor-based systems.

PubMed

Jaghoori, Mohammad Mahdi; de Boer, Frank; Longuet, Delphine; Chothia, Tom; Sirjani, Marjan

2017-01-01

We present an extension of the actor model with real-time, including deadlines associated with messages, and explicit application-level scheduling policies, e.g.,"earliest deadline first" which can be associated with individual actors. Schedulability analysis in this setting amounts to checking whether, given a scheduling policy for each actor, every task is processed within its designated deadline. To check schedulability, we introduce a compositional automata-theoretic approach, based on maximal use of model checking combined with testing. Behavioral interfaces define what an actor expects from the environment, and the deadlines for messages given these assumptions. We use model checking to verify that actors match their behavioral interfaces. We extend timed automata refinement with the notion of deadlines and use it to define compatibility of actor environments with the behavioral interfaces. Model checking of compatibility is computationally hard, so we propose a special testing process. We show that the analyses are decidable and automate the process using the Uppaal model checker.

ANSYS duplicate finite-element checker routine

NASA Technical Reports Server (NTRS)

Ortega, R.

1995-01-01

An ANSYS finite-element code routine to check for duplicated elements within the volume of a three-dimensional (3D) finite-element mesh was developed. The routine developed is used for checking floating elements within a mesh, identically duplicated elements, and intersecting elements with a common face. A space shuttle main engine alternate turbopump development high pressure oxidizer turbopump finite-element model check using the developed subroutine is discussed. Finally, recommendations are provided for duplicate element checking of 3D finite-element models.

Select Neurocognitive Impairment in HIV-Infected Women: Associations with HIV Viral Load, Hepatitis C Virus, and Depression, but Not Leukocyte Telomere Length

PubMed Central

Giesbrecht, Chantelle J.; Thornton, Allen E.; Hall-Patch, Clare; Maan, Evelyn J.; Côté, Hélène C. F.; Money, Deborah M.; Murray, Melanie; Pick, Neora

2014-01-01

Background Through implementation of combination antiretroviral therapy (cART) remarkable gains have been achieved in the management of HIV infection; nonetheless, the neurocognitive consequences of infection remain a pivotal concern in the cART era. Research has often employed norm-referenced neuropsychological scores, derived from healthy populations (excluding many seronegative individuals at high risk for HIV infection), to characterize impairments in predominately male HIV-infected populations. Methods Using matched-group methodology, we assessed 81 HIV-seropositive (HIV+) women with established neuropsychological measures validated for detection of HIV-related impairments, as well as additional detailed tests of executive function and decision-making from the Cambridge Neuropsychological Test Automated Battery (CANTAB). Results On validated tests, the HIV+ women exhibited impairments that were limited to significantly slower information processing speed when compared with 45 HIV-seronegative (HIV−) women with very similar demographic backgrounds and illness comorbidities. Additionally, select executive impairments in shifting attention (i.e., reversal learning) and in decision-making quality were revealed in HIV+ participants. Modifiers of neurocognition in HIV-infected women included detectable HIV plasma viral load, active hepatitis C virus co-infection, and self-reported depression symptoms. In contrast, leukocyte telomere length (LTL), a marker of cellular aging, did not significantly differ between HIV+ and HIV− women, nor was LTL associated with overall neurocognition in the HIV+ group. Conclusions The findings suggest that well-managed HIV infection may entail a more circumscribed neurocognitive deficit pattern than that reported in many norm-referenced studies, and that common comorbidities make a secondary contribution to HIV-related neurocognitive impairments. PMID:24595021

Pharmacist and Technician Perceptions of Tech-Check-Tech in Community Pharmacy Practice Settings.

PubMed

Frost, Timothy P; Adams, Alex J

2018-04-01

Tech-check-tech (TCT) is a practice model in which pharmacy technicians with advanced training can perform final verification of prescriptions that have been previously reviewed for appropriateness by a pharmacist. Few states have adopted TCT in part because of the common view that this model is controversial among members of the profession. This article aims to summarize the existing research on pharmacist and technician perceptions of community pharmacy-based TCT. A literature review was conducted using MEDLINE (January 1990 to August 2016) and Google Scholar (January 1990 to August 2016) using the terms "tech* and check," "tech-check-tech," "checking technician," and "accuracy checking tech*." Of the 7 studies identified we found general agreement among both pharmacists and technicians that TCT in community pharmacy settings can be safely performed. This agreement persisted in studies of theoretical TCT models and in studies assessing participants in actual community-based TCT models. Pharmacists who had previously worked with a checking technician were generally more favorable toward TCT. Both pharmacists and technicians in community pharmacy settings generally perceived TCT to be safe, in both theoretical surveys and in surveys following actual TCT demonstration projects. These perceptions of safety align well with the actual outcomes achieved from community pharmacy TCT studies.

Movement Correction Method for Human Brain PET Images: Application to Quantitative Analysis of Dynamic [18F]-FDDNP Scans

PubMed Central

Wardak, Mirwais; Wong, Koon-Pong; Shao, Weber; Dahlbom, Magnus; Kepe, Vladimir; Satyamurthy, Nagichettiar; Small, Gary W.; Barrio, Jorge R.; Huang, Sung-Cheng

2010-01-01

Head movement during a PET scan (especially, dynamic scan) can affect both the qualitative and quantitative aspects of an image, making it difficult to accurately interpret the results. The primary objective of this study was to develop a retrospective image-based movement correction (MC) method and evaluate its implementation on dynamic [18F]-FDDNP PET images of cognitively intact controls and patients with Alzheimer’s disease (AD). Methods Dynamic [18F]-FDDNP PET images, used for in vivo imaging of beta-amyloid plaques and neurofibrillary tangles, were obtained from 12 AD and 9 age-matched controls. For each study, a transmission scan was first acquired for attenuation correction. An accurate retrospective MC method that corrected for transmission-emission misalignment as well as emission-emission misalignment was applied to all studies. No restriction was assumed for zero movement between the transmission scan and first emission scan. Logan analysis with cerebellum as the reference region was used to estimate various regional distribution volume ratio (DVR) values in the brain before and after MC. Discriminant analysis was used to build a predictive model for group membership, using data with and without MC. Results MC improved the image quality and quantitative values in [18F]-FDDNP PET images. In this subject population, medial temporal (MTL) did not show a significant difference between controls and AD before MC. However, after MC, significant differences in DVR values were seen in frontal, parietal, posterior cingulate (PCG), MTL, lateral temporal (LTL), and global between the two groups (P < 0.05). In controls and AD, the variability of regional DVR values (as measured by the coefficient of variation) decreased on average by >18% after MC. Mean DVR separation between controls and ADs was higher in frontal, MTL, LTL and global after MC. Group classification by discriminant analysis based on [18F]-FDDNP DVR values was markedly improved after MC. Conclusion The streamlined and easy to use MC method presented in this work significantly improves the image quality and the measured tracer kinetics of [18F]-FDDNP PET images. The proposed MC method has the potential to be applied to PET studies on patients having other disorders (e.g., Down syndrome and Parkinson’s disease) and to brain PET scans with other molecular imaging probes. PMID:20080894

Model Checking the Remote Agent Planner

NASA Technical Reports Server (NTRS)

Khatib, Lina; Muscettola, Nicola; Havelund, Klaus; Norvig, Peter (Technical Monitor)

2001-01-01

This work tackles the problem of using Model Checking for the purpose of verifying the HSTS (Scheduling Testbed System) planning system. HSTS is the planner and scheduler of the remote agent autonomous control system deployed in Deep Space One (DS1). Model Checking allows for the verification of domain models as well as planning entries. We have chosen the real-time model checker UPPAAL for this work. We start by motivating our work in the introduction. Then we give a brief description of HSTS and UPPAAL. After that, we give a sketch for the mapping of HSTS models into UPPAAL and we present samples of plan model properties one may want to verify.

Random Testing and Model Checking: Building a Common Framework for Nondeterministic Exploration

NASA Technical Reports Server (NTRS)

Groce, Alex; Joshi, Rajeev

2008-01-01

Two popular forms of dynamic analysis, random testing and explicit-state software model checking, are perhaps best viewed as search strategies for exploring the state spaces introduced by nondeterminism in program inputs. We present an approach that enables this nondeterminism to be expressed in the SPIN model checker's PROMELA language, and then lets users generate either model checkers or random testers from a single harness for a tested C program. Our approach makes it easy to compare model checking and random testing for models with precisely the same input ranges and probabilities and allows us to mix random testing with model checking's exhaustive exploration of non-determinism. The PROMELA language, as intended in its design, serves as a convenient notation for expressing nondeterminism and mixing random choices with nondeterministic choices. We present and discuss a comparison of random testing and model checking. The results derive from using our framework to test a C program with an effectively infinite state space, a module in JPL's next Mars rover mission. More generally, we show how the ability of the SPIN model checker to call C code can be used to extend SPIN's features, and hope to inspire others to use the same methods to implement dynamic analyses that can make use of efficient state storage, matching, and backtracking.

CheckMATE 2: From the model to the limit

NASA Astrophysics Data System (ADS)

Dercks, Daniel; Desai, Nishita; Kim, Jong Soo; Rolbiecki, Krzysztof; Tattersall, Jamie; Weber, Torsten

2017-12-01

We present the latest developments to the CheckMATE program that allows models of new physics to be easily tested against the recent LHC data. To achieve this goal, the core of CheckMATE now contains over 60 LHC analyses of which 12 are from the 13 TeV run. The main new feature is that CheckMATE 2 now integrates the Monte Carlo event generation via MadGraph5_aMC@NLO and Pythia 8. This allows users to go directly from a SLHA file or UFO model to the result of whether a model is allowed or not. In addition, the integration of the event generation leads to a significant increase in the speed of the program. Many other improvements have also been made, including the possibility to now combine signal regions to give a total likelihood for a model.

Coverage Metrics for Model Checking

NASA Technical Reports Server (NTRS)

Penix, John; Visser, Willem; Norvig, Peter (Technical Monitor)

2001-01-01

When using model checking to verify programs in practice, it is not usually possible to achieve complete coverage of the system. In this position paper we describe ongoing research within the Automated Software Engineering group at NASA Ames on the use of test coverage metrics to measure partial coverage and provide heuristic guidance for program model checking. We are specifically interested in applying and developing coverage metrics for concurrent programs that might be used to support certification of next generation avionics software.

Forced Draft Blowers, Duct Work For

DTIC Science & Technology

1935-06-01

il l~!! · ;Jp iiH X j H ~ rt ’l ~t;Jn; J!1 ’’ild .at~ rfl: 1:;!( ~rLtf {: PJ : tf1 :~ff:’n’’ !lh1~rt ~1~ · ., , •.. ’ , l,l·,tr t’t’t,m,;l ~ ·rr. I I...Jii ~ ~ ~~~~·htt tt ill· IQ\\u ·· ~t ~ lrt 111 t{~ ifub!ilL 0ii :trtW!,ff.’ : · tj tf1 -l-!1 ’ ·• ll·ld~Htf ’II ’t 1 lrl lll ld u [ 1 · ~ :,· l~ltl

ISS Payload Racks Automated Flow Control Calibration Method

NASA Technical Reports Server (NTRS)

Simmonds, Boris G.

2003-01-01

Payload Racks utilize MTL and/or LTL station water for cooling of payloads and avionics. Flow control range from valves of fully closed, to up to 300 Ibmhr. Instrument accuracies are as high as f 7.5 Ibm/hr for flow sensors and f 3 Ibm/hr for valve controller, for a total system accuracy of f 10.5 Ibm/hr. Improved methodology was developed, tested and proven that reduces accuracy of the commanded flows to less than f 1 Ibmhr. Uethodology could be packed in a "calibration kit" for on- orbit flow sensor checkout and recalibration, extending the rack operations before return to earth. -

European Symposium on X-Ray Topography and High Resolution Diffraction (2nd) Held in Berlin, Germany on 5-7 September 1994. Programme and Abstracts

DTIC Science & Technology

1994-09-07

RELAXATION OF NANOSTRUCTURED SIGE/SI PILLARS BY HIGH-RESOLUTION X-RAY DIFFRACTION P. van der Sluis and C.W.T. Bull.-Lieuwma PLillps Research Laboratories...whereas the lattice is fully strained in large (10xlO mm2) pillars. (1] P.B. Fischer and S.Y. Chou, Appl. Phys. Lett. 62, 1414 (1993) (2) P. van der ...tIn, hi&ttttV (Thl)ttLtl Of epitaxial layers of 111I-V compoutnds, J1. Cl’ybll GIVILth, Vol. 44:1)1.5113 :-517, 1978. (2) P. van der Sluls Determination

Posterior Predictive Model Checking in Bayesian Networks

ERIC Educational Resources Information Center

Crawford, Aaron

2014-01-01

This simulation study compared the utility of various discrepancy measures within a posterior predictive model checking (PPMC) framework for detecting different types of data-model misfit in multidimensional Bayesian network (BN) models. The investigated conditions were motivated by an applied research program utilizing an operational complex…

Analyzing the cost of screening selectee and non-selectee baggage.

PubMed

Virta, Julie L; Jacobson, Sheldon H; Kobza, John E

2003-10-01

Determining how to effectively operate security devices is as important to overall system performance as developing more sensitive security devices. In light of recent federal mandates for 100% screening of all checked baggage, this research studies the trade-offs between screening only selectee checked baggage and screening both selectee and non-selectee checked baggage for a single baggage screening security device deployed at an airport. This trade-off is represented using a cost model that incorporates the cost of the baggage screening security device, the volume of checked baggage processed through the device, and the outcomes that occur when the device is used. The cost model captures the cost of deploying, maintaining, and operating a single baggage screening security device over a one-year period. The study concludes that as excess baggage screening capacity is used to screen non-selectee checked bags, the expected annual cost increases, the expected annual cost per checked bag screened decreases, and the expected annual cost per expected number of threats detected in the checked bags screened increases. These results indicate that the marginal increase in security per dollar spent is significantly lower when non-selectee checked bags are screened than when only selectee checked bags are screened.

40 CFR 86.327-79 - Quench checks; NOX analyzer.

Code of Federal Regulations, 2010 CFR

2010-07-01

... Quench checks; NOX analyzer. (a) Perform the reaction chamber quench check for each model of high vacuum reaction chamber analyzer prior to initial use. (b) Perform the reaction chamber quench check for each new analyzer that has an ambient pressure or “soft vacuum” reaction chamber prior to initial use. Additionally...

40 CFR 86.327-79 - Quench checks; NOX analyzer.

Code of Federal Regulations, 2011 CFR

2011-07-01

... Quench checks; NOX analyzer. (a) Perform the reaction chamber quench check for each model of high vacuum reaction chamber analyzer prior to initial use. (b) Perform the reaction chamber quench check for each new analyzer that has an ambient pressure or “soft vacuum” reaction chamber prior to initial use. Additionally...

Phase Two Feasibility Study for Software Safety Requirements Analysis Using Model Checking

NASA Technical Reports Server (NTRS)

Turgeon, Gregory; Price, Petra

2010-01-01

A feasibility study was performed on a representative aerospace system to determine the following: (1) the benefits and limitations to using SCADE , a commercially available tool for model checking, in comparison to using a proprietary tool that was studied previously [1] and (2) metrics for performing the model checking and for assessing the findings. This study was performed independently of the development task by a group unfamiliar with the system, providing a fresh, external perspective free from development bias.

MPST Software: grl_pef_check

NASA Technical Reports Server (NTRS)

Call, Jared A.; Kwok, John H.; Fisher, Forest W.

2013-01-01

This innovation is a tool used to verify and validate spacecraft sequences at the predicted events file (PEF) level for the GRAIL (Gravity Recovery and Interior Laboratory, see http://www.nasa. gov/mission_pages/grail/main/index. html) mission as part of the Multi-Mission Planning and Sequencing Team (MPST) operations process to reduce the possibility for errors. This tool is used to catch any sequence related errors or issues immediately after the seqgen modeling to streamline downstream processes. This script verifies and validates the seqgen modeling for the GRAIL MPST process. A PEF is provided as input, and dozens of checks are performed on it to verify and validate the command products including command content, command ordering, flight-rule violations, modeling boundary consistency, resource limits, and ground commanding consistency. By performing as many checks as early in the process as possible, grl_pef_check streamlines the MPST task of generating GRAIL command and modeled products on an aggressive schedule. By enumerating each check being performed, and clearly stating the criteria and assumptions made at each step, grl_pef_check can be used as a manual checklist as well as an automated tool. This helper script was written with a focus on enabling the user with the information they need in order to evaluate a sequence quickly and efficiently, while still keeping them informed and active in the overall sequencing process. grl_pef_check verifies and validates the modeling and sequence content prior to investing any more effort into the build. There are dozens of various items in the modeling run that need to be checked, which is a time-consuming and errorprone task. Currently, no software exists that provides this functionality. Compared to a manual process, this script reduces human error and saves considerable man-hours by automating and streamlining the mission planning and sequencing task for the GRAIL mission.

Practical Formal Verification of Diagnosability of Large Models via Symbolic Model Checking

NASA Technical Reports Server (NTRS)

Cavada, Roberto; Pecheur, Charles

2003-01-01

This document reports on the activities carried out during a four-week visit of Roberto Cavada at the NASA Ames Research Center. The main goal was to test the practical applicability of the framework proposed, where a diagnosability problem is reduced to a Symbolic Model Checking problem. Section 2 contains a brief explanation of major techniques currently used in Symbolic Model Checking, and how these techniques can be tuned in order to obtain good performances when using Model Checking tools. Diagnosability is performed on large and structured models of real plants. Section 3 describes how these plants are modeled, and how models can be simplified to improve the performance of Symbolic Model Checkers. Section 4 reports scalability results. Three test cases are briefly presented, and several parameters and techniques have been applied on those test cases in order to produce comparison tables. Furthermore, comparison between several Model Checkers is reported. Section 5 summarizes the application of diagnosability verification to a real application. Several properties have been tested, and results have been highlighted. Finally, section 6 draws some conclusions, and outlines future lines of research.

Non-equilibrium dog-flea model

NASA Astrophysics Data System (ADS)

Ackerson, Bruce J.

2017-11-01

We develop the open dog-flea model to serve as a check of proposed non-equilibrium theories of statistical mechanics. The model is developed in detail. Then it is applied to four recent models for non-equilibrium statistical mechanics. Comparison of the dog-flea solution with these different models allows checking claims and giving a concrete example of the theoretical models.

Prediction of a service demand using combined forecasting approach

NASA Astrophysics Data System (ADS)

Zhou, Ling

2017-08-01

Forecasting facilitates cutting down operational and management costs while ensuring service level for a logistics service provider. Our case study here is to investigate how to forecast short-term logistic demand for a LTL carrier. Combined approach depends on several forecasting methods simultaneously, instead of a single method. It can offset the weakness of a forecasting method with the strength of another, which could improve the precision performance of prediction. Main issues of combined forecast modeling are how to select methods for combination, and how to find out weight coefficients among methods. The principles of method selection include that each method should apply to the problem of forecasting itself, also methods should differ in categorical feature as much as possible. Based on these principles, exponential smoothing, ARIMA and Neural Network are chosen to form the combined approach. Besides, least square technique is employed to settle the optimal weight coefficients among forecasting methods. Simulation results show the advantage of combined approach over the three single methods. The work done in the paper helps manager to select prediction method in practice.

Abstraction and Assume-Guarantee Reasoning for Automated Software Verification

NASA Technical Reports Server (NTRS)

Chaki, S.; Clarke, E.; Giannakopoulou, D.; Pasareanu, C. S.

2004-01-01

Compositional verification and abstraction are the key techniques to address the state explosion problem associated with model checking of concurrent software. A promising compositional approach is to prove properties of a system by checking properties of its components in an assume-guarantee style. This article proposes a framework for performing abstraction and assume-guarantee reasoning of concurrent C code in an incremental and fully automated fashion. The framework uses predicate abstraction to extract and refine finite state models of software and it uses an automata learning algorithm to incrementally construct assumptions for the compositional verification of the abstract models. The framework can be instantiated with different assume-guarantee rules. We have implemented our approach in the COMFORT reasoning framework and we show how COMFORT out-performs several previous software model checking approaches when checking safety properties of non-trivial concurrent programs.

Incremental checking of Master Data Management model based on contextual graphs

NASA Astrophysics Data System (ADS)

Lamolle, Myriam; Menet, Ludovic; Le Duc, Chan

2015-10-01

The validation of models is a crucial step in distributed heterogeneous systems. In this paper, an incremental validation method is proposed in the scope of a Model Driven Engineering (MDE) approach, which is used to develop a Master Data Management (MDM) field represented by XML Schema models. The MDE approach presented in this paper is based on the definition of an abstraction layer using UML class diagrams. The validation method aims to minimise the model errors and to optimisethe process of model checking. Therefore, the notion of validation contexts is introduced allowing the verification of data model views. Description logics specify constraints that the models have to check. An experimentation of the approach is presented through an application developed in ArgoUML IDE.

Model Checking - My 27-Year Quest to Overcome the State Explosion Problem

NASA Technical Reports Server (NTRS)

Clarke, Ed

2009-01-01

Model Checking is an automatic verification technique for state-transition systems that are finite=state or that have finite-state abstractions. In the early 1980 s in a series of joint papers with my graduate students E.A. Emerson and A.P. Sistla, we proposed that Model Checking could be used for verifying concurrent systems and gave algorithms for this purpose. At roughly the same time, Joseph Sifakis and his student J.P. Queille at the University of Grenoble independently developed a similar technique. Model Checking has been used successfully to reason about computer hardware and communication protocols and is beginning to be used for verifying computer software. Specifications are written in temporal logic, which is particularly valuable for expressing concurrency properties. An intelligent, exhaustive search is used to determine if the specification is true or not. If the specification is not true, the Model Checker will produce a counterexample execution trace that shows why the specification does not hold. This feature is extremely useful for finding obscure errors in complex systems. The main disadvantage of Model Checking is the state-explosion problem, which can occur if the system under verification has many processes or complex data structures. Although the state-explosion problem is inevitable in worst case, over the past 27 years considerable progress has been made on the problem for certain classes of state-transition systems that occur often in practice. In this talk, I will describe what Model Checking is, how it works, and the main techniques that have been developed for combating the state explosion problem.

A Multidimensional Item Response Model: Constrained Latent Class Analysis Using the Gibbs Sampler and Posterior Predictive Checks.

ERIC Educational Resources Information Center

Hoijtink, Herbert; Molenaar, Ivo W.

1997-01-01

This paper shows that a certain class of constrained latent class models may be interpreted as a special case of nonparametric multidimensional item response models. Parameters of this latent class model are estimated using an application of the Gibbs sampler, and model fit is investigated using posterior predictive checks. (SLD)

Construct validity and reliability of the Single Checking Administration of Medications Scale.

PubMed

O'Connell, Beverly; Hawkins, Mary; Ockerby, Cherene

2013-06-01

Research indicates that single checking of medications is as safe as double checking; however, many nurses are averse to independently checking medications. To assist with the introduction and use of single checking, a measure of nurses' attitudes, the thirteen-item Single Checking Administration of Medications Scale (SCAMS) was developed. We examined the psychometric properties of the SCAMS. Secondary analyses were conducted on data collected from 503 nurses across a large Australian health-care service. Analyses using exploratory and confirmatory factor analyses supported by structural equation modelling resulted in a valid twelve-item SCAMS containing two reliable subscales, the nine-item Attitudes towards single checking and three-item Advantages of single checking subscales. The SCAMS is recommended as a valid and reliable measure for monitoring nurses' attitudes to single checking prior to introducing single checking medications and after its implementation. © 2013 Wiley Publishing Asia Pty Ltd.

Simulation-based model checking approach to cell fate specification during Caenorhabditis elegans vulval development by hybrid functional Petri net with extension.

PubMed

Li, Chen; Nagasaki, Masao; Ueno, Kazuko; Miyano, Satoru

2009-04-27

Model checking approaches were applied to biological pathway validations around 2003. Recently, Fisher et al. have proved the importance of model checking approach by inferring new regulation of signaling crosstalk in C. elegans and confirming the regulation with biological experiments. They took a discrete and state-based approach to explore all possible states of the system underlying vulval precursor cell (VPC) fate specification for desired properties. However, since both discrete and continuous features appear to be an indispensable part of biological processes, it is more appropriate to use quantitative models to capture the dynamics of biological systems. Our key motivation of this paper is to establish a quantitative methodology to model and analyze in silico models incorporating the use of model checking approach. A novel method of modeling and simulating biological systems with the use of model checking approach is proposed based on hybrid functional Petri net with extension (HFPNe) as the framework dealing with both discrete and continuous events. Firstly, we construct a quantitative VPC fate model with 1761 components by using HFPNe. Secondly, we employ two major biological fate determination rules - Rule I and Rule II - to VPC fate model. We then conduct 10,000 simulations for each of 48 sets of different genotypes, investigate variations of cell fate patterns under each genotype, and validate the two rules by comparing three simulation targets consisting of fate patterns obtained from in silico and in vivo experiments. In particular, an evaluation was successfully done by using our VPC fate model to investigate one target derived from biological experiments involving hybrid lineage observations. However, the understandings of hybrid lineages are hard to make on a discrete model because the hybrid lineage occurs when the system comes close to certain thresholds as discussed by Sternberg and Horvitz in 1986. Our simulation results suggest that: Rule I that cannot be applied with qualitative based model checking, is more reasonable than Rule II owing to the high coverage of predicted fate patterns (except for the genotype of lin-15ko; lin-12ko double mutants). More insights are also suggested. The quantitative simulation-based model checking approach is a useful means to provide us valuable biological insights and better understandings of biological systems and observation data that may be hard to capture with the qualitative one.

The Priority Inversion Problem and Real-Time Symbolic Model Checking

DTIC Science & Technology

1993-04-23

real time systems unpredictable in subtle ways. This makes it more difficult to implement and debug such systems. Our work discusses this problem and presents one possible solution. The solution is formalized and verified using temporal logic model checking techniques. In order to perform the verification, the BDD-based symbolic model checking algorithm given in previous works was extended to handle real-time properties using the bounded until operator. We believe that this algorithm, which is based on discrete time, is able to handle many real-time properties

Design of Installing Check Dam Using RAMMS Model in Seorak National Park of South Korea

NASA Astrophysics Data System (ADS)

Jun, K.; Tak, W.; JUN, B. H.; Lee, H. J.; KIM, S. D.

2016-12-01

Design of Installing Check Dam Using RAMMS Model in Seorak National Park of South Korea Kye-Won Jun*, Won-Jun Tak*, Byong-Hee Jun**, Ho-Jin Lee***, Soung-Doug Kim* *Graduate School of Disaster Prevention, Kangwon National University, 346 Joogang-ro, Samcheok-si, Gangwon-do, Korea **School of Fire and Disaster Protection, Kangwon National University, 346 Joogang-ro, Samcheok-si, Gangwon-do, Korea ***School of Civil Engineering, Chungbuk National University, 1 Chungdae-ro, Seowon-gu, Cheongju, Korea Abstract As more than 64% of the land in South Korea is mountainous area, so many regions in South Korea are exposed to the danger of landslide and debris flow. So it is important to understand the behavior of debris flow in mountainous terrains, the various methods and models are being presented and developed based on the mathematical concept. The purpose of this study is to investigate the regions that experienced the debris flow due to typhoon called Ewiniar and to perform numerical modeling to design and layout of the Check dam for reducing the damage by the debris flow. For the performance of numerical modeling, on-site measurement of the research area was conducted including: topographic investigation, research on bridges in the downstream, and precision LiDAR 3D scanning for composed basic data of numerical modeling. The numerical simulation of this study was performed using RAMMS (Rapid Mass Movements Simulation) model for the analysis of the debris flow. This model applied to the conditions of the Check dam which was installed in the upstream, midstream, and downstream. Considering the reduction effect of debris flow, the expansion of debris flow, and the influence on the bridges in the downstream, proper location of the Check dam was designated. The result of present numerical model showed that when the Check dam was installed in the downstream section, 50 m above the bridge, the reduction effect of the debris flow was higher compared to when the Check dam were installed in other sections. Key words: Debris flow, LiDAR, Check dam, RAMMSAcknowledgementsThis research was supported by a grant [MPSS-NH-2014-74] through the Disaster and Safety Management Institute funded by Ministry of Public Safety and Security of Korean government

Model building strategy for logistic regression: purposeful selection.

PubMed

Zhang, Zhongheng

2016-03-01

Logistic regression is one of the most commonly used models to account for confounders in medical literature. The article introduces how to perform purposeful selection model building strategy with R. I stress on the use of likelihood ratio test to see whether deleting a variable will have significant impact on model fit. A deleted variable should also be checked for whether it is an important adjustment of remaining covariates. Interaction should be checked to disentangle complex relationship between covariates and their synergistic effect on response variable. Model should be checked for the goodness-of-fit (GOF). In other words, how the fitted model reflects the real data. Hosmer-Lemeshow GOF test is the most widely used for logistic regression model.

HiVy automated translation of stateflow designs for model checking verification

NASA Technical Reports Server (NTRS)

Pingree, Paula

2003-01-01

tool set enables model checking of finite state machines designs. This is acheived by translating state-chart specifications into the input language of the Spin model checker. An abstract syntax of hierarchical sequential automata (HSA) is provided as an intermediate format tool set.

Petri Net and Probabilistic Model Checking Based Approach for the Modelling, Simulation and Verification of Internet Worm Propagation

PubMed Central

Razzaq, Misbah; Ahmad, Jamil

2015-01-01

Internet worms are analogous to biological viruses since they can infect a host and have the ability to propagate through a chosen medium. To prevent the spread of a worm or to grasp how to regulate a prevailing worm, compartmental models are commonly used as a means to examine and understand the patterns and mechanisms of a worm spread. However, one of the greatest challenge is to produce methods to verify and validate the behavioural properties of a compartmental model. This is why in this study we suggest a framework based on Petri Nets and Model Checking through which we can meticulously examine and validate these models. We investigate Susceptible-Exposed-Infectious-Recovered (SEIR) model and propose a new model Susceptible-Exposed-Infectious-Recovered-Delayed-Quarantined (Susceptible/Recovered) (SEIDQR(S/I)) along with hybrid quarantine strategy, which is then constructed and analysed using Stochastic Petri Nets and Continuous Time Markov Chain. The analysis shows that the hybrid quarantine strategy is extremely effective in reducing the risk of propagating the worm. Through Model Checking, we gained insight into the functionality of compartmental models. Model Checking results validate simulation ones well, which fully support the proposed framework. PMID:26713449

Petri Net and Probabilistic Model Checking Based Approach for the Modelling, Simulation and Verification of Internet Worm Propagation.

PubMed

Razzaq, Misbah; Ahmad, Jamil

2015-01-01

Internet worms are analogous to biological viruses since they can infect a host and have the ability to propagate through a chosen medium. To prevent the spread of a worm or to grasp how to regulate a prevailing worm, compartmental models are commonly used as a means to examine and understand the patterns and mechanisms of a worm spread. However, one of the greatest challenge is to produce methods to verify and validate the behavioural properties of a compartmental model. This is why in this study we suggest a framework based on Petri Nets and Model Checking through which we can meticulously examine and validate these models. We investigate Susceptible-Exposed-Infectious-Recovered (SEIR) model and propose a new model Susceptible-Exposed-Infectious-Recovered-Delayed-Quarantined (Susceptible/Recovered) (SEIDQR(S/I)) along with hybrid quarantine strategy, which is then constructed and analysed using Stochastic Petri Nets and Continuous Time Markov Chain. The analysis shows that the hybrid quarantine strategy is extremely effective in reducing the risk of propagating the worm. Through Model Checking, we gained insight into the functionality of compartmental models. Model Checking results validate simulation ones well, which fully support the proposed framework.

Immediate Effects of Body Checking Behaviour on Negative and Positive Emotions in Women with Eating Disorders: An Ecological Momentary Assessment Approach.

PubMed

Kraus, Nicole; Lindenberg, Julia; Zeeck, Almut; Kosfelder, Joachim; Vocks, Silja

2015-09-01

Cognitive-behavioural models of eating disorders state that body checking arises in response to negative emotions in order to reduce the aversive emotional state and is therefore negatively reinforced. This study empirically tests this assumption. For a seven-day period, women with eating disorders (n = 26) and healthy controls (n = 29) were provided with a handheld computer for assessing occurring body checking strategies as well as negative and positive emotions. Serving as control condition, randomized computer-emitted acoustic signals prompted reports on body checking and emotions. There was no difference in the intensity of negative emotions before body checking and in control situations across groups. However, from pre- to post-body checking, an increase in negative emotions was found. This effect was more pronounced in women with eating disorders compared with healthy controls. Results are contradictory to the assumptions of the cognitive-behavioural model, as body checking does not seem to reduce negative emotions. Copyright © 2015 John Wiley & Sons, Ltd and Eating Disorders Association.

Model Diagnostics for Bayesian Networks

ERIC Educational Resources Information Center

Sinharay, Sandip

2006-01-01

Bayesian networks are frequently used in educational assessments primarily for learning about students' knowledge and skills. There is a lack of works on assessing fit of Bayesian networks. This article employs the posterior predictive model checking method, a popular Bayesian model checking tool, to assess fit of simple Bayesian networks. A…

The dopamine D2/D3 receptor agonist quinpirole increases checking-like behaviour in an operant observing response task with uncertain reinforcement: A novel possible model of OCD?

PubMed Central

Eagle, Dawn M.; Noschang, Cristie; d’Angelo, Laure-Sophie Camilla; Noble, Christie A.; Day, Jacob O.; Dongelmans, Marie Louise; Theobald, David E.; Mar, Adam C.; Urcelay, Gonzalo P.; Morein-Zamir, Sharon; Robbins, Trevor W.

2014-01-01

Excessive checking is a common, debilitating symptom of obsessive-compulsive disorder (OCD). In an established rodent model of OCD checking behaviour, quinpirole (dopamine D2/3-receptor agonist) increased checking in open-field tests, indicating dopaminergic modulation of checking-like behaviours. We designed a novel operant paradigm for rats (observing response task (ORT)) to further examine cognitive processes underpinning checking behaviour and clarify how and why checking develops. We investigated i) how quinpirole increases checking, ii) dependence of these effects on D2/3 receptor function (following treatment with D2/3 receptor antagonist sulpiride) and iii) effects of reward uncertainty. In the ORT, rats pressed an ‘observing’ lever for information about the location of an ‘active’ lever that provided food reinforcement. High- and low-checkers (defined from baseline observing) received quinpirole (0.5 mg/kg, 10 treatments) or vehicle. Parametric task manipulations assessed observing/checking under increasing task demands relating to reinforcement uncertainty (variable response requirement and active-lever location switching). Treatment with sulpiride further probed the pharmacological basis of long-term behavioural changes. Quinpirole selectively increased checking, both functional observing lever presses (OLPs) and non-functional extra OLPs (EOLPs). The increase in OLPs and EOLPs was long-lasting, without further quinpirole administration. Quinpirole did not affect the immediate ability to use information from checking. Vehicle and quinpirole-treated rats (VEH and QNP respectively) were selectively sensitive to different forms of uncertainty. Sulpiride reduced non-functional EOLPs in QNP rats but had no effect on functional OLPs. These data have implications for treatment of compulsive checking in OCD, particularly for serotonin-reuptake-inhibitor treatment-refractory cases, where supplementation with dopamine receptor antagonists may be beneficial. PMID:24406720

Perpetual Model Validation

DTIC Science & Technology

2017-03-01

models of software execution, for example memory access patterns, to check for security intrusions. Additional research was performed to tackle the...considered using indirect models of software execution, for example memory access patterns, to check for security intrusions. Additional research ...deterioration for example , no longer corresponds to the model used during verification time. Finally, the research looked at ways to combine hybrid systems

Cultural Resource Reconnaissance of U.S. Army Corps of Engineers Land Alongside Lake Sakakawea in Dunn County, North Dakota. Volume 2. Appendix B (32DU723) through Appendix M

DTIC Science & Technology

1987-11-01

a Twp . R ,...,.. Sec , , , QQQ -i QQ a- Q " LTL L-i Twp . R Sec s. QQQ aJ QQ ’ Q " FEATURE TYPE CULTURAL MATERIAL m. x m. .- Conical Timber Lodge...a,~ Dist Perm Water Perm Water Type Dist Seas Water Seas Water Type - L,3. m.n. n ,_ Ownership Ownership .I A1,11,6 Fieldwork Date I ,LI , Fieldwork...aJEcozone a- Area Signf m o i l . 1 , MS Number a .- CR Type L-AVerified Site L. Non-Site ., E C F ,T F = . State Registry a. National Register<. Coder / ;,f

Proceedings of the Second NASA Formal Methods Symposium

NASA Technical Reports Server (NTRS)

Munoz, Cesar (Editor)

2010-01-01

This publication contains the proceedings of the Second NASA Formal Methods Symposium sponsored by the National Aeronautics and Space Administration and held in Washington D.C. April 13-15, 2010. Topics covered include: Decision Engines for Software Analysis using Satisfiability Modulo Theories Solvers; Verification and Validation of Flight-Critical Systems; Formal Methods at Intel -- An Overview; Automatic Review of Abstract State Machines by Meta Property Verification; Hardware-independent Proofs of Numerical Programs; Slice-based Formal Specification Measures -- Mapping Coupling and Cohesion Measures to Formal Z; How Formal Methods Impels Discovery: A Short History of an Air Traffic Management Project; A Machine-Checked Proof of A State-Space Construction Algorithm; Automated Assume-Guarantee Reasoning for Omega-Regular Systems and Specifications; Modeling Regular Replacement for String Constraint Solving; Using Integer Clocks to Verify the Timing-Sync Sensor Network Protocol; Can Regulatory Bodies Expect Efficient Help from Formal Methods?; Synthesis of Greedy Algorithms Using Dominance Relations; A New Method for Incremental Testing of Finite State Machines; Verification of Faulty Message Passing Systems with Continuous State Space in PVS; Phase Two Feasibility Study for Software Safety Requirements Analysis Using Model Checking; A Prototype Embedding of Bluespec System Verilog in the PVS Theorem Prover; SimCheck: An Expressive Type System for Simulink; Coverage Metrics for Requirements-Based Testing: Evaluation of Effectiveness; Software Model Checking of ARINC-653 Flight Code with MCP; Evaluation of a Guideline by Formal Modelling of Cruise Control System in Event-B; Formal Verification of Large Software Systems; Symbolic Computation of Strongly Connected Components Using Saturation; Towards the Formal Verification of a Distributed Real-Time Automotive System; Slicing AADL Specifications for Model Checking; Model Checking with Edge-valued Decision Diagrams; and Data-flow based Model Analysis.

Proceedings of the First NASA Formal Methods Symposium

NASA Technical Reports Server (NTRS)

Denney, Ewen (Editor); Giannakopoulou, Dimitra (Editor); Pasareanu, Corina S. (Editor)

2009-01-01

Topics covered include: Model Checking - My 27-Year Quest to Overcome the State Explosion Problem; Applying Formal Methods to NASA Projects: Transition from Research to Practice; TLA+: Whence, Wherefore, and Whither; Formal Methods Applications in Air Transportation; Theorem Proving in Intel Hardware Design; Building a Formal Model of a Human-Interactive System: Insights into the Integration of Formal Methods and Human Factors Engineering; Model Checking for Autonomic Systems Specified with ASSL; A Game-Theoretic Approach to Branching Time Abstract-Check-Refine Process; Software Model Checking Without Source Code; Generalized Abstract Symbolic Summaries; A Comparative Study of Randomized Constraint Solvers for Random-Symbolic Testing; Component-Oriented Behavior Extraction for Autonomic System Design; Automated Verification of Design Patterns with LePUS3; A Module Language for Typing by Contracts; From Goal-Oriented Requirements to Event-B Specifications; Introduction of Virtualization Technology to Multi-Process Model Checking; Comparing Techniques for Certified Static Analysis; Towards a Framework for Generating Tests to Satisfy Complex Code Coverage in Java Pathfinder; jFuzz: A Concolic Whitebox Fuzzer for Java; Machine-Checkable Timed CSP; Stochastic Formal Correctness of Numerical Algorithms; Deductive Verification of Cryptographic Software; Coloured Petri Net Refinement Specification and Correctness Proof with Coq; Modeling Guidelines for Code Generation in the Railway Signaling Context; Tactical Synthesis Of Efficient Global Search Algorithms; Towards Co-Engineering Communicating Autonomous Cyber-Physical Systems; and Formal Methods for Automated Diagnosis of Autosub 6000.

Model analysis of check dam impacts on long-term sediment and water budgets in southeast Arizona, USA

USGS Publications Warehouse

Norman, Laura M.; Niraula, Rewati

2016-01-01

The objective of this study was to evaluate the effect of check dam infrastructure on soil and water conservation at the catchment scale using the Soil and Water Assessment Tool (SWAT). This paired watershed study includes a watershed treated with over 2000 check dams and a Control watershed which has none, in the West Turkey Creek watershed, Southeast Arizona, USA. SWAT was calibrated for streamflow using discharge documented during the summer of 2013 at the Control site. Model results depict the necessity to eliminate lateral flow from SWAT models of aridland environments, the urgency to standardize geospatial soils data, and the care for which modelers must document altering parameters when presenting findings. Performance was assessed using the percent bias (PBIAS), with values of ±2.34%. The calibrated model was then used to examine the impacts of check dams at the Treated watershed. Approximately 630 tons of sediment is estimated to be stored behind check dams in the Treated watershed over the 3-year simulation, increasing water quality for fish habitat. A minimum precipitation event of 15 mm was necessary to instigate the detachment of soil, sediments, or rock from the study area, which occurred 2% of the time. The resulting watershed model is useful as a predictive framework and decision-support tool to consider long-term impacts of restoration and potential for future restoration.

New Results in Software Model Checking and Analysis

NASA Technical Reports Server (NTRS)

Pasareanu, Corina S.

2010-01-01

This introductory article surveys new techniques, supported by automated tools, for the analysis of software to ensure reliability and safety. Special focus is on model checking techniques. The article also introduces the five papers that are enclosed in this special journal volume.

Query Language for Location-Based Services: A Model Checking Approach

NASA Astrophysics Data System (ADS)

Hoareau, Christian; Satoh, Ichiro

We present a model checking approach to the rationale, implementation, and applications of a query language for location-based services. Such query mechanisms are necessary so that users, objects, and/or services can effectively benefit from the location-awareness of their surrounding environment. The underlying data model is founded on a symbolic model of space organized in a tree structure. Once extended to a semantic model for modal logic, we regard location query processing as a model checking problem, and thus define location queries as hybrid logicbased formulas. Our approach is unique to existing research because it explores the connection between location models and query processing in ubiquitous computing systems, relies on a sound theoretical basis, and provides modal logic-based query mechanisms for expressive searches over a decentralized data structure. A prototype implementation is also presented and will be discussed.

LC-MS/MS method for the simultaneous quantification of luteolin, wedelolactone and apigenin in mice plasma using hansen solubility parameters for liquid-liquid extraction: Application to pharmacokinetics of Eclipta alba chloroform fraction.

PubMed

Cheruvu, Hanumanth Srikanth; Yadav, Navneet K; Valicherla, Guru R; Arya, Rakesh K; Hussain, Zakir; Sharma, Chetan; Arya, Kamal R; Singh, Rama K; Datta, Dipak; Gayen, Jiaur R

2018-04-01

Eclipta alba (Bhringraj) in ayurveda has been widely used as a traditional medicine for its multi-therapeutic properties for ages. Luteolin (LTL), wedelolactone (WDL) and apigenin (APG) are the three main bioactive phytochemicals present in Eclipta alba extract. However there was a lack of sensitive bioanalytical method for the pharmacokinetics of these free compounds in plasma which majorly contributes for their activities after oral administration of Eclipta alba. The present study aims to develop a sensitive, rapid and reliable liquid chromatography tandem mass spectrometry (LC-MS/MS) method for the simultaneous estimation of mice plasma concentrations of LTL, WDL and APG using quercetin as an internal standard for the pharmacokinetic analysis. Analytes were separated on Phenomenex Luna C18 (150 × 4.6 mm, 3.0 μm) column with mobile phase containing methanol: acetonitrile (90: 10, v/v) and 0.1% formic acid in 10 mM ammonium formate buffer in the ratio of 70: 30 (v/v) in isocratic mode. Liquid-liquid extraction was optimized using Hansen solubility parameters and diethyl ether finalized as an extraction solvent for the recovery ranging from 61 to 76% for all analytes in mice plasma. The validated method has an accuracy and precision over the linearity range of 0.1-200 ng/mL with a correlation coefficient (r 2 ) of ≥0.997. The intra and inter-day assay accuracy was between 98.17 and 107% and 95.83-107.89% respectively and the intra and inter day assay precision ranged from 0.37-6.05% and 1.85-10.76%, respectively for all the analytes. This validated method can be used for future clinical investigation studies of Eclipta alba extracts. Copyright © 2018 Elsevier B.V. All rights reserved.

Design, Specification, and Synthesis of Aircraft Electric Power Systems Control Logic

NASA Astrophysics Data System (ADS)

Xu, Huan

Cyber-physical systems integrate computation, networking, and physical processes. Substantial research challenges exist in the design and verification of such large-scale, distributed sensing, actuation, and control systems. Rapidly improving technology and recent advances in control theory, networked systems, and computer science give us the opportunity to drastically improve our approach to integrated flow of information and cooperative behavior. Current systems rely on text-based specifications and manual design. Using new technology advances, we can create easier, more efficient, and cheaper ways of developing these control systems. This thesis will focus on design considerations for system topologies, ways to formally and automatically specify requirements, and methods to synthesize reactive control protocols, all within the context of an aircraft electric power system as a representative application area. This thesis consists of three complementary parts: synthesis, specification, and design. The first section focuses on the synthesis of central and distributed reactive controllers for an aircraft elec- tric power system. This approach incorporates methodologies from computer science and control. The resulting controllers are correct by construction with respect to system requirements, which are formulated using the specification language of linear temporal logic (LTL). The second section addresses how to formally specify requirements and introduces a domain-specific language for electric power systems. A software tool automatically converts high-level requirements into LTL and synthesizes a controller. The final sections focus on design space exploration. A design methodology is proposed that uses mixed-integer linear programming to obtain candidate topologies, which are then used to synthesize controllers. The discrete-time control logic is then verified in real-time by two methods: hardware and simulation. Finally, the problem of partial observability and dynamic state estimation is explored. Given a set placement of sensors on an electric power system, measurements from these sensors can be used in conjunction with control logic to infer the state of the system.

Systematic Review of Cognitive Function in Euthymic Bipolar Disorder and Pre-Surgical Temporal Lobe Epilepsy.

PubMed

Bostock, Emmanuelle C S; Kirkby, Kenneth C; Garry, Michael I; Taylor, Bruce V M

2017-01-01

Bipolar disorder (BD) and temporal lobe epilepsy (TLE) overlap in domains including epidemiology, treatment response, shared neurotransmitter involvement and temporal lobe pathology. Comparison of cognitive function in both disorders may indicate temporal lobe mediated processes relevant to BD. This systematic review examines neuropsychological test profiles in euthymic bipolar disorder type I (BD-I) and pre-surgical TLE and compares experimental designs used. A search of PubMed, PsychINFO, and Scopus using Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines was conducted. Inclusion criteria were comparison group or pre- to post-surgical patients; reported neuropsychological tests; participants aged 18-60 years. Fifty six studies met criteria: 27 BD-I; 29 TLE. Deficits in BD-I compared to healthy controls (HC) were in executive function, attention span and verbal memory. Deficits in TLE compared to HC were in executive function and memory. In the pre- to post-surgical comparisons, verbal memory in left temporal lobe (LTL) and, less consistently, visuospatial memory in right temporal lobe (RTL) epilepsy declined following surgery. BD-I studies used comprehensive test batteries in well-defined euthymic patients compared to matched HC groups. TLE studies used convenience samples pre- to post-surgery, comparing LTL and RTL subgroups, few included comparisons to HC (5 studies). TLE studies typically examined a narrow range of known temporal lobe-mediated neuropsychological functions, particularly verbal and visuospatial memory. Both disorders exhibit deficits in executive function and verbal memory suggestive of both frontal and temporal lobe involvement. However, deficits in TLE are measured pre- to post-surgery and not controlled at baseline pre-surgery. Further research involving a head-to-head comparison of the two disorders on a broad range of neuropsychological tests is needed to clarify the nature and extent of cognitive deficits and potential overlaps.

Abstraction Techniques for Parameterized Verification

DTIC Science & Technology

2006-11-01

approach for applying model checking to unbounded systems is to extract finite state models from them using conservative abstraction techniques. Prop...36 2.5.1 Multiple Reference Processes . . . . . . . . . . . . . . . . . . . 36 2.5.2 Adding Monitor Processes...model checking to complex pieces of code like device drivers depends on the use of abstraction methods. An abstraction method extracts a small finite

The Automation of Nowcast Model Assessment Processes

DTIC Science & Technology

2016-09-01

that will automate real-time WRE-N model simulations, collect and quality control check weather observations for assimilation and verification, and...domains centered near White Sands Missile Range, New Mexico, where the Meteorological Sensor Array (MSA) will be located. The MSA will provide...observations and performing quality -control checks for the pre-forecast data assimilation period. 2. Run the WRE-N model to generate model forecast data

Temporal Precedence Checking for Switched Models and its Application to a Parallel Landing Protocol

NASA Technical Reports Server (NTRS)

Duggirala, Parasara Sridhar; Wang, Le; Mitra, Sayan; Viswanathan, Mahesh; Munoz, Cesar A.

2014-01-01

This paper presents an algorithm for checking temporal precedence properties of nonlinear switched systems. This class of properties subsume bounded safety and capture requirements about visiting a sequence of predicates within given time intervals. The algorithm handles nonlinear predicates that arise from dynamics-based predictions used in alerting protocols for state-of-the-art transportation systems. It is sound and complete for nonlinear switch systems that robustly satisfy the given property. The algorithm is implemented in the Compare Execute Check Engine (C2E2) using validated simulations. As a case study, a simplified model of an alerting system for closely spaced parallel runways is considered. The proposed approach is applied to this model to check safety properties of the alerting logic for different operating conditions such as initial velocities, bank angles, aircraft longitudinal separation, and runway separation.

The method of a joint intraday security check system based on cloud computing

NASA Astrophysics Data System (ADS)

Dong, Wei; Feng, Changyou; Zhou, Caiqi; Cai, Zhi; Dan, Xu; Dai, Sai; Zhang, Chuancheng

2017-01-01

The intraday security check is the core application in the dispatching control system. The existing security check calculation only uses the dispatch center’s local model and data as the functional margin. This paper introduces the design of all-grid intraday joint security check system based on cloud computing and its implementation. To reduce the effect of subarea bad data on the all-grid security check, a new power flow algorithm basing on comparison and adjustment with inter-provincial tie-line plan is presented. And the numerical example illustrated the effectiveness and feasibility of the proposed method.

76 FR 35344 - Airworthiness Directives; Costruzioni Aeronautiche Tecnam srl Model P2006T Airplanes

Federal Register 2010, 2011, 2012, 2013, 2014

2011-06-17

... retraction/extension ground checks performed on the P2006T, a loose Seeger ring was found on the nose landing... specified products. The MCAI states: During Landing Gear retraction/extension ground checks performed on the... airworthiness information (MCAI) states: During Landing Gear retraction/extension ground checks performed on the...

Sediment trapping efficiency of adjustable check dam in laboratory and field experiment

NASA Astrophysics Data System (ADS)

Wang, Chiang; Chen, Su-Chin; Lu, Sheng-Jui

2014-05-01

Check dam has been constructed at mountain area to block debris flow, but has been filled after several events and lose its function of trapping. For the reason, the main facilities of our research is the adjustable steel slit check dam, which with the advantages of fast building, easy to remove or adjust it function. When we can remove transverse beams to drain sediments off and keep the channel continuity. We constructed adjustable steel slit check dam on the Landow torrent, Huisun Experiment Forest station as the prototype to compare with model in laboratory. In laboratory experiments, the Froude number similarity was used to design the dam model. The main comparisons focused on types of sediment trapping and removing, sediment discharge, and trapping rate of slit check dam. In different types of removing transverse beam showed different kind of sediment removal and differences on rate of sediment removing, removing rate, and particle size distribution. The sediment discharge in check dam with beams is about 40%~80% of check dam without beams. Furthermore, the spacing of beams is considerable factor to the sediment discharge. In field experiment, this research uses time-lapse photography to record the adjustable steel slit check dam on the Landow torrent. The typhoon Soulik made rainfall amounts of 600 mm in eight hours and induced debris flow in Landow torrent. Image data of time-lapse photography demonstrated that after several sediment transport event the adjustable steel slit check dam was buried by debris flow. The result of lab and field experiments: (1)Adjustable check dam could trap boulders and stop woody debris flow and flush out fine sediment to supply the need of downstream river. (2)The efficiency of sediment trapping in adjustable check dam with transverse beams was significantly improved. (3)The check dam without transverse beams can remove the sediment and keep the ecosystem continuity.

The dopamine D2/D3 receptor agonist quinpirole increases checking-like behaviour in an operant observing response task with uncertain reinforcement: a novel possible model of OCD.

PubMed

Eagle, Dawn M; Noschang, Cristie; d'Angelo, Laure-Sophie Camilla; Noble, Christie A; Day, Jacob O; Dongelmans, Marie Louise; Theobald, David E; Mar, Adam C; Urcelay, Gonzalo P; Morein-Zamir, Sharon; Robbins, Trevor W

2014-05-01

Excessive checking is a common, debilitating symptom of obsessive-compulsive disorder (OCD). In an established rodent model of OCD checking behaviour, quinpirole (dopamine D2/3-receptor agonist) increased checking in open-field tests, indicating dopaminergic modulation of checking-like behaviours. We designed a novel operant paradigm for rats (observing response task (ORT)) to further examine cognitive processes underpinning checking behaviour and clarify how and why checking develops. We investigated i) how quinpirole increases checking, ii) dependence of these effects on D2/3 receptor function (following treatment with D2/3 receptor antagonist sulpiride) and iii) effects of reward uncertainty. In the ORT, rats pressed an 'observing' lever for information about the location of an 'active' lever that provided food reinforcement. High- and low-checkers (defined from baseline observing) received quinpirole (0.5mg/kg, 10 treatments) or vehicle. Parametric task manipulations assessed observing/checking under increasing task demands relating to reinforcement uncertainty (variable response requirement and active-lever location switching). Treatment with sulpiride further probed the pharmacological basis of long-term behavioural changes. Quinpirole selectively increased checking, both functional observing lever presses (OLPs) and non-functional extra OLPs (EOLPs). The increase in OLPs and EOLPs was long-lasting, without further quinpirole administration. Quinpirole did not affect the immediate ability to use information from checking. Vehicle and quinpirole-treated rats (VEH and QNP respectively) were selectively sensitive to different forms of uncertainty. Sulpiride reduced non-functional EOLPs in QNP rats but had no effect on functional OLPs. These data have implications for treatment of compulsive checking in OCD, particularly for serotonin-reuptake-inhibitor treatment-refractory cases, where supplementation with dopamine receptor antagonists may be beneficial. Copyright © 2014 The Authors. Published by Elsevier B.V. All rights reserved.

A Structural Weight Estimation Program (SWEEP) for Aircraft. Volume 2 - Program Integration and Data Management Module. Part 2: Data Management Module

DTIC Science & Technology

1974-06-01

IVNI11.0VN< >l 11. lUlmi 11 .IMII III11. IUIMI11 .DWI I’ll 11.1 «Ml 11 . OvNi 11111 UUIMUMf lirullll.OIMTIKIII cauiv«»« lire111■ .OVHTIm11.iir»ii...tt III. IMONI11 , OVNI lilt, IDONt 11 ttM«ltl I >, I0W(I I .OVNIll I >. ItLNI 11 .OWml) >, (KNI11 .OVNISI11, lOLMI I > .OVNlftl 11, IITNI11 .DWI Ittt...IHCIMI11 .OVNItl > I. IKUII 11 .avNiti 11. inewi 11 , OVNI ion i. iram 11 .owi Hill cauiviLCHCC wimii>.DVNIitlII.IVIVNID.OVNIHI»i. lUIINID.OVNMSIII

Effects of protein phosphorylation on color stability of ground meat.

PubMed

Li, Meng; Li, Xin; Xin, Jianzeng; Li, Zheng; Li, Guixia; Zhang, Yan; Du, Manting; Shen, Qingwu W; Zhang, Dequan

2017-03-15

The influence of protein phosphorylation on meat color stability was investigated in this study. Phosphatase and protein kinase inhibitors were added to minced ovine Longissimus thoracis et lumborum (LTL) muscle to manipulate the global phosphorylation of sarcoplasmic proteins. The data obtained show that the rate and extent of pH decline, along with lactate accumulation in postmortem muscle, were related to protein phosphorylation. Analysis of meat color and the relative content of myoglobin redox forms revealed that meat color stability was inversely related to the phosphorylation of sarcoplasmic proteins. Thus, this study suggests that protein phosphorylation may be involved in meat color development by regulating glycolysis and the redox stability of myoglobin. Copyright © 2016 Elsevier Ltd. All rights reserved.

An experimental method to verify soil conservation by check dams on the Loess Plateau, China.

PubMed

Xu, X Z; Zhang, H W; Wang, G Q; Chen, S C; Dang, W Q

2009-12-01

A successful experiment with a physical model requires necessary conditions of similarity. This study presents an experimental method with a semi-scale physical model. The model is used to monitor and verify soil conservation by check dams in a small watershed on the Loess Plateau of China. During experiments, the model-prototype ratio of geomorphic variables was kept constant under each rainfall event. Consequently, experimental data are available for verification of soil erosion processes in the field and for predicting soil loss in a model watershed with check dams. Thus, it can predict the amount of soil loss in a catchment. This study also mentions four criteria: similarities of watershed geometry, grain size and bare land, Froude number (Fr) for rainfall event, and soil erosion in downscaled models. The efficacy of the proposed method was confirmed using these criteria in two different downscaled model experiments. The B-Model, a large scale model, simulates watershed prototype. The two small scale models, D(a) and D(b), have different erosion rates, but are the same size. These two models simulate hydraulic processes in the B-Model. Experiment results show that while soil loss in the small scale models was converted by multiplying the soil loss scale number, it was very close to that of the B-Model. Obviously, with a semi-scale physical model, experiments are available to verify and predict soil loss in a small watershed area with check dam system on the Loess Plateau, China.

75 FR 27406 - Airworthiness Directives; Bombardier, Inc. Model BD-100-1A10 (Challenger 300) Airplanes

Federal Register 2010, 2011, 2012, 2013, 2014

2010-05-17

... BD- 100 Time Limits/Maintenance Checks. The actions described in this service information are... Challenger 300 BD-100 Time Limits/Maintenance Checks. (1) For the new tasks identified in Bombardier TR 5-2... Requirements,'' in Part 2 of Chapter 5 of Bombardier Challenger 300 BD-100 Time Limits/ Maintenance Checks...

75 FR 66655 - Airworthiness Directives; PILATUS Aircraft Ltd. Model PC-7 Airplanes

Federal Register 2010, 2011, 2012, 2013, 2014

2010-10-29

... December 3, 2010 (the effective date of this AD), check the airplane maintenance records to determine if... of the airplane. Do this check following paragraph 3.A. of Pilatus Aircraft Ltd. PC-7 Service... maintenance records check required in paragraph (f)(1) of this AD or it is unclear whether or not the left and...

77 FR 20520 - Airworthiness Directives; Bombardier, Inc. Model BD-100-1A10 (Challenger 300) Airplanes

Federal Register 2010, 2011, 2012, 2013, 2014

2012-04-05

... Bombardier Challenger 300 BD-100 Time Limits/Maintenance Checks Manual. For this task, the initial compliance..., of Part 2, of the Bombardier Challenger 300 BD-100 Time Limits/Maintenance Checks Manual, the general.../Maintenance Checks Manual, provided that the relevant information in the general revision is identical to that...

"I share, therefore I am": personality traits, life satisfaction, and Facebook check-ins.

PubMed

Wang, Shaojung Sharon

2013-12-01

This study explored whether agreeableness, extraversion, and openness function to influence self-disclosure behavior, which in turn impacts the intensity of checking in on Facebook. A complete path from extraversion to Facebook check-in through self-disclosure and sharing was found. The indirect effect from sharing to check-in intensity through life satisfaction was particularly salient. The central component of check-in is for users to disclose a specific location selectively that has implications on demonstrating their social lives, lifestyles, and tastes, enabling a selective and optimized self-image. Implications on the hyperpersonal model and warranting principle are discussed.

A Game-Theoretic Approach to Branching Time Abstract-Check-Refine Process

NASA Technical Reports Server (NTRS)

Wang, Yi; Tamai, Tetsuo

2009-01-01

Since the complexity of software systems continues to grow, most engineers face two serious problems: the state space explosion problem and the problem of how to debug systems. In this paper, we propose a game-theoretic approach to full branching time model checking on three-valued semantics. The three-valued models and logics provide successful abstraction that overcomes the state space explosion problem. The game style model checking that generates counter-examples can guide refinement or identify validated formulas, which solves the system debugging problem. Furthermore, output of our game style method will give significant information to engineers in detecting where errors have occurred and what the causes of the errors are.

Concrete Model Checking with Abstract Matching and Refinement

NASA Technical Reports Server (NTRS)

Pasareanu Corina S.; Peianek Radek; Visser, Willem

2005-01-01

We propose an abstraction-based model checking method which relies on refinement of an under-approximation of the feasible behaviors of the system under analysis. The method preserves errors to safety properties, since all analyzed behaviors are feasible by definition. The method does not require an abstract transition relation to he generated, but instead executes the concrete transitions while storing abstract versions of the concrete states, as specified by a set of abstraction predicates. For each explored transition. the method checks, with the help of a theorem prover, whether there is any loss of precision introduced by abstraction. The results of these checks are used to decide termination or to refine the abstraction, by generating new abstraction predicates. If the (possibly infinite) concrete system under analysis has a finite bisimulation quotient, then the method is guaranteed to eventually explore an equivalent finite bisimilar structure. We illustrate the application of the approach for checking concurrent programs. We also show how a lightweight variant can be used for efficient software testing.

Logic Model Checking of Unintended Acceleration Claims in Toyota Vehicles

NASA Technical Reports Server (NTRS)

Gamble, Ed

2012-01-01

Part of the US Department of Transportation investigation of Toyota sudden unintended acceleration (SUA) involved analysis of the throttle control software, JPL Laboratory for Reliable Software applied several techniques including static analysis and logic model checking, to the software; A handful of logic models were build, Some weaknesses were identified; however, no cause for SUA was found; The full NASA report includes numerous other analyses

Logic Model Checking of Unintended Acceleration Claims in the 2005 Toyota Camry Electronic Throttle Control System

NASA Technical Reports Server (NTRS)

Gamble, Ed; Holzmann, Gerard

2011-01-01

Part of the US DOT investigation of Toyota SUA involved analysis of the throttle control software. JPL LaRS applied several techniques, including static analysis and logic model checking, to the software. A handful of logic models were built. Some weaknesses were identified; however, no cause for SUA was found. The full NASA report includes numerous other analyses

Model selection and assessment for multi­-species occupancy models

USGS Publications Warehouse

Broms, Kristin M.; Hooten, Mevin B.; Fitzpatrick, Ryan M.

2016-01-01

While multi-species occupancy models (MSOMs) are emerging as a popular method for analyzing biodiversity data, formal checking and validation approaches for this class of models have lagged behind. Concurrent with the rise in application of MSOMs among ecologists, a quiet regime shift is occurring in Bayesian statistics where predictive model comparison approaches are experiencing a resurgence. Unlike single-species occupancy models that use integrated likelihoods, MSOMs are usually couched in a Bayesian framework and contain multiple levels. Standard model checking and selection methods are often unreliable in this setting and there is only limited guidance in the ecological literature for this class of models. We examined several different contemporary Bayesian hierarchical approaches for checking and validating MSOMs and applied these methods to a freshwater aquatic study system in Colorado, USA, to better understand the diversity and distributions of plains fishes. Our findings indicated distinct differences among model selection approaches, with cross-validation techniques performing the best in terms of prediction.

76 FR 53348 - Airworthiness Directives; BAE SYSTEMS (Operations) Limited Model BAe 146 Airplanes and Model Avro...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-08-26

... Maintenance Manual (AMM) includes chapters 05-10 ``Time Limits'', 05-15 ``Critical Design Configuration... 05, ``Time Limits/Maintenance Checks,'' of BAe 146 Series/AVRO 146-RJ Series Aircraft Maintenance... Chapter 05, ``Time Limits/ Maintenance Checks,'' of the BAE SYSTEMS (Operations) Limited BAe 146 Series...

78 FR 40063 - Airworthiness Directives; Erickson Air-Crane Incorporated Helicopters (Type Certificate...

Federal Register 2010, 2011, 2012, 2013, 2014

2013-07-03

... Sikorsky Model S-64E helicopters. The AD requires repetitive checks of the Blade Inspection Method (BIM... and check procedures for BIM blades installed on the Model S-64F helicopters. Several blade spars with a crack emanating from corrosion pits and other damage have been found because of BIM pressure...

Slicing AADL Specifications for Model Checking

NASA Technical Reports Server (NTRS)

Odenbrett, Maximilian; Nguyen, Viet Yen; Noll, Thomas

2010-01-01

To combat the state-space explosion problem in model checking larger systems, abstraction techniques can be employed. Here, methods that operate on the system specification before constructing its state space are preferable to those that try to minimize the resulting transition system as they generally reduce peak memory requirements. We sketch a slicing algorithm for system specifications written in (a variant of) the Architecture Analysis and Design Language (AADL). Given a specification and a property to be verified, it automatically removes those parts of the specification that are irrelevant for model checking the property, thus reducing the size of the corresponding transition system. The applicability and effectiveness of our approach is demonstrated by analyzing the state-space reduction for an example, employing a translator from AADL to Promela, the input language of the SPIN model checker.

Genistein versus ICI 182, 780: an ally or enemy in metastatic progression of prostate cancer.

PubMed

Nakamura, Hisae; Wang, Yuwei; Xue, Hui; Romanish, Mark T; Mager, Dixie L; Helgason, Cheryl D; Wang, Yuzhuo

2013-12-01

Androgen signalling through the androgen receptor (AR) plays a critical role in prostate cancer (PCa) initiation and progression. Estrogen in synergy with androgen is essential for cell growth of the normal and malignant prostate. However, the exact role that estrogen and the estrogen receptor play in prostate carcinogenesis remains unclear. We have previously demonstrated the metastasis-promoting effect of an estrogen receptor beta (ERβ) agonist (genistein) in a patient-derived PCa xenograft model mimicking localized and metastatic disease. To test the hypothesis that the tumor-promoting activity of genistein was due to its estrogenic properties, we treated the xenograft-bearing mice with genistein and an anti-estrogen compound (ICI 182, 780) and compared the differential gene expression using microarrays. Using a second xenograft model which was derived from another patient, we showed that genistein promoted disease progression in vivo and ICI 182, 780 inhibited metastatic spread. The microarray analysis revealed that the metallothionein (MT) gene family was differentially expressed in tumors treated by these compounds. Using qRT-PCR, the differences in expression levels were validated in the metastatic and non-metastatic LTL313 PCa xenograft tumor lines, both of which were originally derived from the same PCa patient. Together our data provide evidence that genistein stimulates and ICI 182, 780 inhibits metastatic progression, suggesting that these effects may be mediated by ERβ signalling. © 2013 Wiley Periodicals, Inc.

75 FR 42585 - Airworthiness Directives; Empresa Brasileira de Aeronautica S.A. (EMBRAER) Model ERJ 170 and ERJ...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-07-22

... (Low Stage Bleed Check Valve) specified in Section 1 of the EMBRAER 170 Maintenance Review Board Report...-11-02-002 (Low Stage Bleed Check Valve), specified in Section 1 of the EMBRAER 170 Maintenance Review... Task 36-11-02-002 (Low Stage Bleed Check Valve) specified in Section 1 of the EMBRAER 170 Maintenance...

75 FR 9816 - Airworthiness Directives; Empresa Brasileira de Aeronautica S.A. (EMBRAER) Model ERJ 170 and ERJ...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-03-04

... maintenance plan to include repetitive functional tests of the low-stage check valve. For certain other... program to include maintenance Task Number 36-11-02- 002 (Low Stage Bleed Check Valve), specified in... Check Valve) in Section 1 of the EMBRAER 170 Maintenance Review Board Report MRB-1621. Issued in Renton...

75 FR 39811 - Airworthiness Directives; The Boeing Company Model 777 Airplanes

Federal Register 2010, 2011, 2012, 2013, 2014

2010-07-13

... Service Bulletin 777-57A0064, dated March 26, 2009, it is not necessary to perform the torque check on the... instructions in Boeing Alert Service Bulletin 777-57A0064, dated March 26, 2009, a torque check is redundant... are less than those for the torque check. Boeing notes that it plans to issue a new revision to this...

Checking Dimensionality in Item Response Models with Principal Component Analysis on Standardized Residuals

ERIC Educational Resources Information Center

Chou, Yeh-Tai; Wang, Wen-Chung

2010-01-01

Dimensionality is an important assumption in item response theory (IRT). Principal component analysis on standardized residuals has been used to check dimensionality, especially under the family of Rasch models. It has been suggested that an eigenvalue greater than 1.5 for the first eigenvalue signifies a violation of unidimensionality when there…

Stress analysis of 27% scale model of AH-64 main rotor hub

NASA Technical Reports Server (NTRS)

Hodges, R. V.

1985-01-01

Stress analysis of an AH-64 27% scale model rotor hub was performed. Component loads and stresses were calculated based upon blade root loads and motions. The static and fatigue analysis indicates positive margins of safety in all components checked. Using the format developed here, the hub can be stress checked for future application.

Do alcohol compliance checks decrease underage sales at neighboring establishments?

PubMed

Erickson, Darin J; Smolenski, Derek J; Toomey, Traci L; Carlin, Bradley P; Wagenaar, Alexander C

2013-11-01

Underage alcohol compliance checks conducted by law enforcement agencies can reduce the likelihood of illegal alcohol sales at checked alcohol establishments, and theory suggests that an alcohol establishment that is checked may warn nearby establishments that compliance checks are being conducted in the area. In this study, we examined whether the effects of compliance checks diffuse to neighboring establishments. We used data from the Complying with the Minimum Drinking Age trial, which included more than 2,000 compliance checks conducted at more than 900 alcohol establishments. The primary outcome was the sale of alcohol to a pseudo-underage buyer without the need for age identification. A multilevel logistic regression was used to model the effect of a compliance check at each establishment as well as the effect of compliance checks at neighboring establishments within 500 m (stratified into four equal-radius concentric rings), after buyer, license, establishment, and community-level variables were controlled for. We observed a decrease in the likelihood of establishments selling alcohol to underage youth after they had been checked by law enforcement, but these effects quickly decayed over time. Establishments that had a close neighbor (within 125 m) checked in the past 90 days were also less likely to sell alcohol to young-appearing buyers. The spatial effect of compliance checks on other establishments decayed rapidly with increasing distance. Results confirm the hypothesis that the effects of police compliance checks do spill over to neighboring establishments. These findings have implications for the development of an optimal schedule of police compliance checks.

Observational analysis on inflammatory reaction to talc pleurodesis: Small and large animal model series review

PubMed Central

Vannucci, Jacopo; Bellezza, Guido; Matricardi, Alberto; Moretti, Giulia; Bufalari, Antonello; Cagini, Lucio; Puma, Francesco; Daddi, Niccolò

2018-01-01

Talc pleurodesis has been associated with pleuropulmonary damage, particularly long-term damage due to its inert nature. The present model series review aimed to assess the safety of this procedure by examining inflammatory stimulus, biocompatibility and tissue reaction following talc pleurodesis. Talc slurry was performed in rabbits: 200 mg/kg checked at postoperative day 14 (five models), 200 mg/kg checked at postoperative day 28 (five models), 40 mg/kg, checked at postoperative day 14 (five models), 40 mg/kg checked at postoperative day 28 (five models). Talc poudrage was performed in pigs: 55 mg/kg checked at postoperative day 60 (18 models). Tissue inspection and data collection followed the surgical pathology approach currently used in clinical practice. As this was an observational study, no statistical analysis was performed. Regarding the rabbit model (Oryctolagus cunicoli), the extent of adhesions ranged between 0 and 30%, and between 0 and 10% following 14 and 28 days, respectively. No intraparenchymal granuloma was observed whereas, pleural granulomas were extensively encountered following both talc dosages, with more evidence of visceral pleura granulomas following 200 mg/kg compared with 40 mg/kg. Severe florid inflammation was observed in 2/10 cases following 40 mg/kg. Parathymic, pericardium granulomas and mediastinal lymphadenopathy were evidenced at 28 days. At 60 days, from rare adhesions to extended pleurodesis were observed in the pig model (Sus Scrofa domesticus). Pleural granulomas were ubiquitous on visceral and parietal pleurae. Severe spotted inflammation among the adhesions were recorded in 15/18 pigs. Intraparenchymal granulomas were observed in 9/18 lungs. Talc produced unpredictable pleurodesis in both animal models with enduring pleural inflammation whether it was performed via slurry or poudrage. Furthermore, talc appeared to have triggered extended pleural damage, intraparenchymal nodules (porcine poudrage) and mediastinal migration (rabbit slurry). PMID:29403549

Analyzing Phylogenetic Trees with Timed and Probabilistic Model Checking: The Lactose Persistence Case Study.

PubMed

Requeno, José Ignacio; Colom, José Manuel

2014-12-01

Model checking is a generic verification technique that allows the phylogeneticist to focus on models and specifications instead of on implementation issues. Phylogenetic trees are considered as transition systems over which we interrogate phylogenetic questions written as formulas of temporal logic. Nonetheless, standard logics become insufficient for certain practices of phylogenetic analysis since they do not allow the inclusion of explicit time and probabilities. The aim of this paper is to extend the application of model checking techniques beyond qualitative phylogenetic properties and adapt the existing logical extensions and tools to the field of phylogeny. The introduction of time and probabilities in phylogenetic specifications is motivated by the study of a real example: the analysis of the ratio of lactose intolerance in some populations and the date of appearance of this phenotype.

Analyzing phylogenetic trees with timed and probabilistic model checking: the lactose persistence case study.

PubMed

Requeno, José Ignacio; Colom, José Manuel

2014-10-23

Model checking is a generic verification technique that allows the phylogeneticist to focus on models and specifications instead of on implementation issues. Phylogenetic trees are considered as transition systems over which we interrogate phylogenetic questions written as formulas of temporal logic. Nonetheless, standard logics become insufficient for certain practices of phylogenetic analysis since they do not allow the inclusion of explicit time and probabilities. The aim of this paper is to extend the application of model checking techniques beyond qualitative phylogenetic properties and adapt the existing logical extensions and tools to the field of phylogeny. The introduction of time and probabilities in phylogenetic specifications is motivated by the study of a real example: the analysis of the ratio of lactose intolerance in some populations and the date of appearance of this phenotype.

Model Checking for Verification of Interactive Health IT Systems

PubMed Central

Butler, Keith A.; Mercer, Eric; Bahrami, Ali; Tao, Cui

2015-01-01

Rigorous methods for design and verification of health IT systems have lagged far behind their proliferation. The inherent technical complexity of healthcare, combined with the added complexity of health information technology makes their resulting behavior unpredictable and introduces serious risk. We propose to mitigate this risk by formalizing the relationship between HIT and the conceptual work that increasingly typifies modern care. We introduce new techniques for modeling clinical workflows and the conceptual products within them that allow established, powerful modeling checking technology to be applied to interactive health IT systems. The new capability can evaluate the workflows of a new HIT system performed by clinicians and computers to improve safety and reliability. We demonstrate the method on a patient contact system to demonstrate model checking is effective for interactive systems and that much of it can be automated. PMID:26958166

Verification and Planning Based on Coinductive Logic Programming

NASA Technical Reports Server (NTRS)

Bansal, Ajay; Min, Richard; Simon, Luke; Mallya, Ajay; Gupta, Gopal

2008-01-01

Coinduction is a powerful technique for reasoning about unfounded sets, unbounded structures, infinite automata, and interactive computations [6]. Where induction corresponds to least fixed point's semantics, coinduction corresponds to greatest fixed point semantics. Recently coinduction has been incorporated into logic programming and an elegant operational semantics developed for it [11, 12]. This operational semantics is the greatest fix point counterpart of SLD resolution (SLD resolution imparts operational semantics to least fix point based computations) and is termed co- SLD resolution. In co-SLD resolution, a predicate goal p( t) succeeds if it unifies with one of its ancestor calls. In addition, rational infinite terms are allowed as arguments of predicates. Infinite terms are represented as solutions to unification equations and the occurs check is omitted during the unification process. Coinductive Logic Programming (Co-LP) and Co-SLD resolution can be used to elegantly perform model checking and planning. A combined SLD and Co-SLD resolution based LP system forms the common basis for planning, scheduling, verification, model checking, and constraint solving [9, 4]. This is achieved by amalgamating SLD resolution, co-SLD resolution, and constraint logic programming [13] in a single logic programming system. Given that parallelism in logic programs can be implicitly exploited [8], complex, compute-intensive applications (planning, scheduling, model checking, etc.) can be executed in parallel on multi-core machines. Parallel execution can result in speed-ups as well as in larger instances of the problems being solved. In the remainder we elaborate on (i) how planning can be elegantly and efficiently performed under real-time constraints, (ii) how real-time systems can be elegantly and efficiently model- checked, as well as (iii) how hybrid systems can be verified in a combined system with both co-SLD and SLD resolution. Implementations of co-SLD resolution as well as preliminary implementations of the planning and verification applications have been developed [4]. Co-LP and Model Checking: The vast majority of properties that are to be verified can be classified into safety properties and liveness properties. It is well known within model checking that safety properties can be verified by reachability analysis, i.e, if a counter-example to the property exists, it can be finitely determined by enumerating all the reachable states of the Kripke structure.

Bayesian model checking: A comparison of tests

NASA Astrophysics Data System (ADS)

Lucy, L. B.

2018-06-01

Two procedures for checking Bayesian models are compared using a simple test problem based on the local Hubble expansion. Over four orders of magnitude, p-values derived from a global goodness-of-fit criterion for posterior probability density functions agree closely with posterior predictive p-values. The former can therefore serve as an effective proxy for the difficult-to-calculate posterior predictive p-values.

Secure open cloud in data transmission using reference pattern and identity with enhanced remote privacy checking

NASA Astrophysics Data System (ADS)

Vijay Singh, Ran; Agilandeeswari, L.

2017-11-01

To handle the large amount of client’s data in open cloud lots of security issues need to be address. Client’s privacy should not be known to other group members without data owner’s valid permission. Sometime clients are fended to have accessing with open cloud servers due to some restrictions. To overcome the security issues and these restrictions related to storing, data sharing in an inter domain network and privacy checking, we propose a model in this paper which is based on an identity based cryptography in data transmission and intermediate entity which have client’s reference with identity that will take control handling of data transmission in an open cloud environment and an extended remote privacy checking technique which will work at admin side. On behalf of data owner’s authority this proposed model will give best options to have secure cryptography in data transmission and remote privacy checking either as private or public or instructed. The hardness of Computational Diffie-Hellman assumption algorithm for key exchange makes this proposed model more secure than existing models which are being used for public cloud environment.

Spot-checks to measure general hygiene practice.

PubMed

Sonego, Ina L; Mosler, Hans-Joachim

2016-01-01

A variety of hygiene behaviors are fundamental to the prevention of diarrhea. We used spot-checks in a survey of 761 households in Burundi to examine whether something we could call general hygiene practice is responsible for more specific hygiene behaviors, ranging from handwashing to sweeping the floor. Using structural equation modeling, we showed that clusters of hygiene behavior, such as primary caregivers' cleanliness and household cleanliness, explained the spot-check findings well. Within our model, general hygiene practice as overall concept explained the more specific clusters of hygiene behavior well. Furthermore, the higher general hygiene practice, the more likely children were to be categorized healthy (r = 0.46). General hygiene practice was correlated with commitment to hygiene (r = 0.52), indicating a strong association to psychosocial determinants. The results show that different hygiene behaviors co-occur regularly. Using spot-checks, the general hygiene practice of a household can be rated quickly and easily.

XMI2USE: A Tool for Transforming XMI to USE Specifications

NASA Astrophysics Data System (ADS)

Sun, Wuliang; Song, Eunjee; Grabow, Paul C.; Simmonds, Devon M.

The UML-based Specification Environment (USE) tool supports syntactic analysis, type checking, consistency checking, and dynamic validation of invariants and pre-/post conditions specified in the Object Constraint Language (OCL). Due to its animation and analysis power, it is useful when checking critical non-functional properties such as security policies. However, the USE tool requires one to specify (i.e., "write") a model using its own textual language and does not allow one to import any model specification files created by other UML modeling tools. Hence, to make the best use of existing UML tools, we often create a model with OCL constraints using a modeling tool such as the IBM Rational Software Architect (RSA) and then use the USE tool for model validation. This approach, however, requires a manual transformation between the specifications of two different tool formats, which is error-prone and diminishes the benefit of automated model-level validations. In this paper, we describe our own implementation of a specification transformation engine that is based on the Model Driven Architecture (MDA) framework and currently supports automatic tool-level transformations from RSA to USE.

Evaluation of properties over phylogenetic trees using stochastic logics.

PubMed

Requeno, José Ignacio; Colom, José Manuel

2016-06-14

Model checking has been recently introduced as an integrated framework for extracting information of the phylogenetic trees using temporal logics as a querying language, an extension of modal logics that imposes restrictions of a boolean formula along a path of events. The phylogenetic tree is considered a transition system modeling the evolution as a sequence of genomic mutations (we understand mutation as different ways that DNA can be changed), while this kind of logics are suitable for traversing it in a strict and exhaustive way. Given a biological property that we desire to inspect over the phylogeny, the verifier returns true if the specification is satisfied or a counterexample that falsifies it. However, this approach has been only considered over qualitative aspects of the phylogeny. In this paper, we repair the limitations of the previous framework for including and handling quantitative information such as explicit time or probability. To this end, we apply current probabilistic continuous-time extensions of model checking to phylogenetics. We reinterpret a catalog of qualitative properties in a numerical way, and we also present new properties that couldn't be analyzed before. For instance, we obtain the likelihood of a tree topology according to a mutation model. As case of study, we analyze several phylogenies in order to obtain the maximum likelihood with the model checking tool PRISM. In addition, we have adapted the software for optimizing the computation of maximum likelihoods. We have shown that probabilistic model checking is a competitive framework for describing and analyzing quantitative properties over phylogenetic trees. This formalism adds soundness and readability to the definition of models and specifications. Besides, the existence of model checking tools hides the underlying technology, omitting the extension, upgrade, debugging and maintenance of a software tool to the biologists. A set of benchmarks justify the feasibility of our approach.

Model Checking Verification and Validation at JPL and the NASA Fairmont IV and V Facility

NASA Technical Reports Server (NTRS)

Schneider, Frank; Easterbrook, Steve; Callahan, Jack; Montgomery, Todd

1999-01-01

We show how a technology transfer effort was carried out. The successful use of model checking on a pilot JPL flight project demonstrates the usefulness and the efficacy of the approach. The pilot project was used to model a complex spacecraft controller. Software design and implementation validation were carried out successfully. To suggest future applications we also show how the implementation validation step can be automated. The effort was followed by the formal introduction of the modeling technique as a part of the JPL Quality Assurance process.

Philosophy and the practice of Bayesian statistics

PubMed Central

Gelman, Andrew; Shalizi, Cosma Rohilla

2015-01-01

A substantial school in the philosophy of science identifies Bayesian inference with inductive inference and even rationality as such, and seems to be strengthened by the rise and practical success of Bayesian statistics. We argue that the most successful forms of Bayesian statistics do not actually support that particular philosophy but rather accord much better with sophisticated forms of hypothetico-deductivism. We examine the actual role played by prior distributions in Bayesian models, and the crucial aspects of model checking and model revision, which fall outside the scope of Bayesian confirmation theory. We draw on the literature on the consistency of Bayesian updating and also on our experience of applied work in social science. Clarity about these matters should benefit not just philosophy of science, but also statistical practice. At best, the inductivist view has encouraged researchers to fit and compare models without checking them; at worst, theorists have actively discouraged practitioners from performing model checking because it does not fit into their framework. PMID:22364575

Philosophy and the practice of Bayesian statistics.

PubMed

Gelman, Andrew; Shalizi, Cosma Rohilla

2013-02-01

A substantial school in the philosophy of science identifies Bayesian inference with inductive inference and even rationality as such, and seems to be strengthened by the rise and practical success of Bayesian statistics. We argue that the most successful forms of Bayesian statistics do not actually support that particular philosophy but rather accord much better with sophisticated forms of hypothetico-deductivism. We examine the actual role played by prior distributions in Bayesian models, and the crucial aspects of model checking and model revision, which fall outside the scope of Bayesian confirmation theory. We draw on the literature on the consistency of Bayesian updating and also on our experience of applied work in social science. Clarity about these matters should benefit not just philosophy of science, but also statistical practice. At best, the inductivist view has encouraged researchers to fit and compare models without checking them; at worst, theorists have actively discouraged practitioners from performing model checking because it does not fit into their framework. © 2012 The British Psychological Society.

A Model-Driven Approach for Telecommunications Network Services Definition

NASA Astrophysics Data System (ADS)

Chiprianov, Vanea; Kermarrec, Yvon; Alff, Patrick D.

Present day Telecommunications market imposes a short concept-to-market time for service providers. To reduce it, we propose a computer-aided, model-driven, service-specific tool, with support for collaborative work and for checking properties on models. We started by defining a prototype of the Meta-model (MM) of the service domain. Using this prototype, we defined a simple graphical modeling language specific for service designers. We are currently enlarging the MM of the domain using model transformations from Network Abstractions Layers (NALs). In the future, we will investigate approaches to ensure the support for collaborative work and for checking properties on models.

A Selected Operational History of the Internal Thermal Control System (ITCS) for International Space Station (ISS)

NASA Technical Reports Server (NTRS)

Patel, Vipul P.; Winton, Dale; Ibarra, Thomas H.

2004-01-01

The Internal Thermal Control System (ITCS) has been developed jointly by Boeing Corporation, Huntsville, Alabama and Honeywell Engines & Systems, Torrance, California to meet the internal thermal control needs for the International Space Station (ISS). The ITCS provides heat removal for the critical life support systems and thermal conditioning for numerous experiment racks. The ITCS will be fitted on a number of modules on the ISS. The first US Element containing the ITCS, Node 1, was launched in December 1998. Since Node 1 does not contain a pump to circulate the fluid it was not filled with ITCS fluid until after the US Laboratory Module was installed. The second US Element module, US Laboratory Module, which contains the pumps and all the major ITCS control hardware, was launched in February 2001. The third US Element containing the ITCS, the US Airlock, was launched in July 2001. The dual loop system of the ITCS is comprised of a lowtemperature loop (LTL) and a moderate-temperature loop (MTL). Each loop has a pump package assembly (PPA), a system flow control assembly (SFCA), a threeway mixing valve (TWMV), several rack flow control assemblies (RFCA), cold plates, pressure sensors, temperature sensors, pump bypass assembly (PBA) and a heat exchanger. In addition, the MTL has an additional TWMV, a payload regeneration heat exchanger (P/RHE) and a manual flow control valve (MFCV). The LTL has a service performance and checkout unit (SPCU) heat exchanger. The two loops are linked via one loop crossover assembly (LCA) providing cross loop capabilities and a single PPA, two-loop functionality. One important parameter monitored by the ground stations and on-orbit is the amount of fluid leakage from the ITCS. ISS fluid leakage is of importance since ITCS fluid is costly to re-supply, may be difficult to clean up in zero-g, and if uncontained could lead to equipment failures and potential hazards. This paper examines the nominal leakage observed over period of a year of on-orbit operation and compares this with analysis predictions. This paper also addresses the off-nominal leakage and a fluid transfer event causing significant changes in accumulator quantity.

Using State Merging and State Pruning to Address the Path Explosion Problem Faced by Symbolic Execution

DTIC Science & Technology

2014-06-19

urgent and compelling. Recent efforts in this area automate program analysis techniques using model checking and symbolic execution [2, 5–7]. These...bounded model checking tool for x86 binary programs developed at the Air Force Institute of Technology (AFIT). Jiseki creates a bit-vector logic model based...assume there are n different paths through the function foo . The program could potentially call the function foo a bound number of times, resulting in n

The Infobiotics Workbench: an integrated in silico modelling platform for Systems and Synthetic Biology.

PubMed

Blakes, Jonathan; Twycross, Jamie; Romero-Campero, Francisco Jose; Krasnogor, Natalio

2011-12-01

The Infobiotics Workbench is an integrated software suite incorporating model specification, simulation, parameter optimization and model checking for Systems and Synthetic Biology. A modular model specification allows for straightforward creation of large-scale models containing many compartments and reactions. Models are simulated either using stochastic simulation or numerical integration, and visualized in time and space. Model parameters and structure can be optimized with evolutionary algorithms, and model properties calculated using probabilistic model checking. Source code and binaries for Linux, Mac and Windows are available at http://www.infobiotics.org/infobiotics-workbench/; released under the GNU General Public License (GPL) version 3. Natalio.Krasnogor@nottingham.ac.uk.

Parallel Software Model Checking

DTIC Science & Technology

2015-01-08

checker. This project will explore this strategy to parallelize the generalized PDR algorithm for software model checking. It belongs to TF1 due to its ... focus on formal verification . Generalized PDR. Generalized Property Driven Rechability (GPDR) i is an algorithm for solving HORN-SMT reachability...subject to a penalty for failing to comply with a collection of information if it does not display a currently valid OMB control number. 1. REPORT DATE 08

Stochastic Game Analysis and Latency Awareness for Self-Adaptation

DTIC Science & Technology

2014-01-01

this paper, we introduce a formal analysis technique based on model checking of stochastic multiplayer games (SMGs) that enables us to quantify the...Additional Key Words and Phrases: Proactive adaptation, Stochastic multiplayer games , Latency 1. INTRODUCTION When planning how to adapt, self-adaptive...contribution of this paper is twofold: (1) A novel analysis technique based on model checking of stochastic multiplayer games (SMGs) that enables us to

Probabilistic Priority Message Checking Modeling Based on Controller Area Networks

NASA Astrophysics Data System (ADS)

Lin, Cheng-Min

Although the probabilistic model checking tool called PRISM has been applied in many communication systems, such as wireless local area network, Bluetooth, and ZigBee, the technique is not used in a controller area network (CAN). In this paper, we use PRISM to model the mechanism of priority messages for CAN because the mechanism has allowed CAN to become the leader in serial communication for automobile and industry control. Through modeling CAN, it is easy to analyze the characteristic of CAN for further improving the security and efficiency of automobiles. The Markov chain model helps us to model the behaviour of priority messages.

MOM: A meteorological data checking expert system in CLIPS

NASA Technical Reports Server (NTRS)

Odonnell, Richard

1990-01-01

Meteorologists have long faced the problem of verifying the data they use. Experience shows that there is a sizable number of errors in the data reported by meteorological observers. This is unacceptable for computer forecast models, which depend on accurate data for accurate results. Most errors that occur in meteorological data are obvious to the meteorologist, but time constraints prevent hand-checking. For this reason, it is necessary to have a 'front end' to the computer model to ensure the accuracy of input. Various approaches to automatic data quality control have been developed by several groups. MOM is a rule-based system implemented in CLIPS and utilizing 'consistency checks' and 'range checks'. The system is generic in the sense that it knows some meteorological principles, regardless of specific station characteristics. Specific constraints kept as CLIPS facts in a separate file provide for system flexibility. Preliminary results show that the expert system has detected some inconsistencies not noticed by a local expert.

Learning Assumptions for Compositional Verification

NASA Technical Reports Server (NTRS)

Cobleigh, Jamieson M.; Giannakopoulou, Dimitra; Pasareanu, Corina; Clancy, Daniel (Technical Monitor)

2002-01-01

Compositional verification is a promising approach to addressing the state explosion problem associated with model checking. One compositional technique advocates proving properties of a system by checking properties of its components in an assume-guarantee style. However, the application of this technique is difficult because it involves non-trivial human input. This paper presents a novel framework for performing assume-guarantee reasoning in an incremental and fully automated fashion. To check a component against a property, our approach generates assumptions that the environment needs to satisfy for the property to hold. These assumptions are then discharged on the rest of the system. Assumptions are computed by a learning algorithm. They are initially approximate, but become gradually more precise by means of counterexamples obtained by model checking the component and its environment, alternately. This iterative process may at any stage conclude that the property is either true or false in the system. We have implemented our approach in the LTSA tool and applied it to the analysis of a NASA system.

Revised Uniform Summary of Surface Weather Observations (RUSSWO) Schwaebisch Hall AAF, DL

DTIC Science & Technology

1979-08-17

TOTAL NUMSE3 YF OSERYATIONS4 USAFETAC 0-85 (OL-AI ,O Nivowrano ef lAS OM AMt cosmf G;L(3ohL C’LTl 2 "iC %1sAFPT C SURFACE WINDS AIR -ET!ER S PERCENTAGE...78 _ V_ on rm StATW NAM TUBS .’" ALL A-"H CIASS NIa ( LA T.) SPEED 1i I i MEAN ENTS) I! 1.3 4.6 7.10 1.16 17-21 22-27 28-31 .4-40 Al .47 48 55 ? :56...Il 2.4 W mw_ -- I* . Es _ _ _i n - ___; - 4 jSFTA 0I -- La Ic.-’ Mvw m.- i kb~ !ULA Hua6fOUMAI4 QSFTC 0’ ~.)PvWSOh401~ m aCSI El (,i U Ir i5 IJSAFCTA

Model-checking techniques based on cumulative residuals.

PubMed

Lin, D Y; Wei, L J; Ying, Z

2002-03-01

Residuals have long been used for graphical and numerical examinations of the adequacy of regression models. Conventional residual analysis based on the plots of raw residuals or their smoothed curves is highly subjective, whereas most numerical goodness-of-fit tests provide little information about the nature of model misspecification. In this paper, we develop objective and informative model-checking techniques by taking the cumulative sums of residuals over certain coordinates (e.g., covariates or fitted values) or by considering some related aggregates of residuals, such as moving sums and moving averages. For a variety of statistical models and data structures, including generalized linear models with independent or dependent observations, the distributions of these stochastic processes tinder the assumed model can be approximated by the distributions of certain zero-mean Gaussian processes whose realizations can be easily generated by computer simulation. Each observed process can then be compared, both graphically and numerically, with a number of realizations from the Gaussian process. Such comparisons enable one to assess objectively whether a trend seen in a residual plot reflects model misspecification or natural variation. The proposed techniques are particularly useful in checking the functional form of a covariate and the link function. Illustrations with several medical studies are provided.

Parameter discovery in stochastic biological models using simulated annealing and statistical model checking.

PubMed

Hussain, Faraz; Jha, Sumit K; Jha, Susmit; Langmead, Christopher J

2014-01-01

Stochastic models are increasingly used to study the behaviour of biochemical systems. While the structure of such models is often readily available from first principles, unknown quantitative features of the model are incorporated into the model as parameters. Algorithmic discovery of parameter values from experimentally observed facts remains a challenge for the computational systems biology community. We present a new parameter discovery algorithm that uses simulated annealing, sequential hypothesis testing, and statistical model checking to learn the parameters in a stochastic model. We apply our technique to a model of glucose and insulin metabolism used for in-silico validation of artificial pancreata and demonstrate its effectiveness by developing parallel CUDA-based implementation for parameter synthesis in this model.

Generalized Symbolic Execution for Model Checking and Testing

NASA Technical Reports Server (NTRS)

Khurshid, Sarfraz; Pasareanu, Corina; Visser, Willem; Kofmeyer, David (Technical Monitor)

2003-01-01

Modern software systems, which often are concurrent and manipulate complex data structures must be extremely reliable. We present a novel framework based on symbolic execution, for automated checking of such systems. We provide a two-fold generalization of traditional symbolic execution based approaches: one, we define a program instrumentation, which enables standard model checkers to perform symbolic execution; two, we give a novel symbolic execution algorithm that handles dynamically allocated structures (e.g., lists and trees), method preconditions (e.g., acyclicity of lists), data (e.g., integers and strings) and concurrency. The program instrumentation enables a model checker to automatically explore program heap configurations (using a systematic treatment of aliasing) and manipulate logical formulae on program data values (using a decision procedure). We illustrate two applications of our framework: checking correctness of multi-threaded programs that take inputs from unbounded domains with complex structure and generation of non-isomorphic test inputs that satisfy a testing criterion. Our implementation for Java uses the Java PathFinder model checker.

Model Checking Degrees of Belief in a System of Agents

NASA Technical Reports Server (NTRS)

Raimondi, Franco; Primero, Giuseppe; Rungta, Neha

2014-01-01

Reasoning about degrees of belief has been investigated in the past by a number of authors and has a number of practical applications in real life. In this paper we present a unified framework to model and verify degrees of belief in a system of agents. In particular, we describe an extension of the temporal-epistemic logic CTLK and we introduce a semantics based on interpreted systems for this extension. In this way, degrees of beliefs do not need to be provided externally, but can be derived automatically from the possible executions of the system, thereby providing a computationally grounded formalism. We leverage the semantics to (a) construct a model checking algorithm, (b) investigate its complexity, (c) provide a Java implementation of the model checking algorithm, and (d) evaluate our approach using the standard benchmark of the dining cryptographers. Finally, we provide a detailed case study: using our framework and our implementation, we assess and verify the situational awareness of the pilot of Air France 447 flying in off-nominal conditions.

Test and Evaluation Report of the IVAC (Trademark) Vital Check Monitor Model 4000AEE

DTIC Science & Technology

1992-02-01

AD-A248 834 111111 jIf+l l’ l USAARL Report No. 92-14 Test and Evaluation Report of the IVAC® Vital Check Monitor DTI ~cModel 4000AEE f ELECTE APR17...does not constitute an official Department of the Army endorsement or approval of the use ot such commercial items. Reviewed: DENNIS F . SHANAHAN LTC, MC...to 12.4 GHz) was scanned for emissions. The IVACO Model 4000AEE was operated with both ac and battery power. 2.10.3.2 The radiated susceptibility

Automated Verification of Specifications with Typestates and Access Permissions

NASA Technical Reports Server (NTRS)

Siminiceanu, Radu I.; Catano, Nestor

2011-01-01

We propose an approach to formally verify Plural specifications based on access permissions and typestates, by model-checking automatically generated abstract state-machines. Our exhaustive approach captures all the possible behaviors of abstract concurrent programs implementing the specification. We describe the formal methodology employed by our technique and provide an example as proof of concept for the state-machine construction rules. The implementation of a fully automated algorithm to generate and verify models, currently underway, provides model checking support for the Plural tool, which currently supports only program verification via data flow analysis (DFA).

Utilisation of preventative health check-ups in the UK: findings from individual-level repeated cross-sectional data from 1992 to 2008

PubMed Central

Labeit, Alexander; Peinemann, Frank; Baker, Richard

2013-01-01

Objectives To analyse and compare the determinants of screening uptake for different National Health Service (NHS) health check-ups in the UK. Design Individual-level analysis of repeated cross-sectional surveys with balanced panel data. Setting The UK. Participants Individuals taking part in the British Household Panel Survey (BHPS), 1992–2008. Outcome measure Uptake of NHS health check-ups for cervical cancer screening, breast cancer screening, blood pressure checks, cholesterol tests, dental screening and eyesight tests. Methods Dynamic panel data models (random effects panel probit with initial conditions). Results Having had a health check-up 1 year before, and previously in accordance with the recommended schedule, was associated with higher uptake of health check-ups. Individuals who visited a general practitioner (GP) had a significantly higher uptake in 5 of the 6 health check-ups. Uptake was highest in the recommended age group for breast and cervical cancer screening. For all health check-ups, age had a non-linear relationship. Lower self-rated health status was associated with increased uptake of blood pressure checks and cholesterol tests; smoking was associated with decreased uptake of 4 health check-ups. The effects of socioeconomic variables differed for the different health check-ups. Ethnicity did not have a significant influence on any health check-up. Permanent household income had an influence only on eyesight tests and dental screening. Conclusions Common determinants for having health check-ups are age, screening history and a GP visit. Policy interventions to increase uptake should consider the central role of the GP in promoting screening examinations and in preserving a high level of uptake. Possible economic barriers to access for prevention exist for dental screening and eyesight tests, and could be a target for policy intervention. Trial registration This observational study was not registered. PMID:24366576

How can machine-learning methods assist in virtual screening for hyperuricemia? A healthcare machine-learning approach.

PubMed

Ichikawa, Daisuke; Saito, Toki; Ujita, Waka; Oyama, Hiroshi

2016-12-01

Our purpose was to develop a new machine-learning approach (a virtual health check-up) toward identification of those at high risk of hyperuricemia. Applying the system to general health check-ups is expected to reduce medical costs compared with administering an additional test. Data were collected during annual health check-ups performed in Japan between 2011 and 2013 (inclusive). We prepared training and test datasets from the health check-up data to build prediction models; these were composed of 43,524 and 17,789 persons, respectively. Gradient-boosting decision tree (GBDT), random forest (RF), and logistic regression (LR) approaches were trained using the training dataset and were then used to predict hyperuricemia in the test dataset. Undersampling was applied to build the prediction models to deal with the imbalanced class dataset. The results showed that the RF and GBDT approaches afforded the best performances in terms of sensitivity and specificity, respectively. The area under the curve (AUC) values of the models, which reflected the total discriminative ability of the classification, were 0.796 [95% confidence interval (CI): 0.766-0.825] for the GBDT, 0.784 [95% CI: 0.752-0.815] for the RF, and 0.785 [95% CI: 0.752-0.819] for the LR approaches. No significant differences were observed between pairs of each approach. Small changes occurred in the AUCs after applying undersampling to build the models. We developed a virtual health check-up that predicted the development of hyperuricemia using machine-learning methods. The GBDT, RF, and LR methods had similar predictive capability. Undersampling did not remarkably improve predictive power. Copyright © 2016 Elsevier Inc. All rights reserved.

Reopen parameter regions in two-Higgs doublet models

NASA Astrophysics Data System (ADS)

Staub, Florian

2018-01-01

The stability of the electroweak potential is a very important constraint for models of new physics. At the moment, it is standard for Two-Higgs doublet models (THDM), singlet or triplet extensions of the standard model to perform these checks at tree-level. However, these models are often studied in the presence of very large couplings. Therefore, it can be expected that radiative corrections to the potential are important. We study these effects at the example of the THDM type-II and find that loop corrections can revive more than 50% of the phenomenological viable points which are ruled out by the tree-level vacuum stability checks. Similar effects are expected for other extension of the standard model.

Verification of Compartmental Epidemiological Models using Metamorphic Testing, Model Checking and Visual Analytics

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ramanathan, Arvind; Steed, Chad A; Pullum, Laura L

Compartmental models in epidemiology are widely used as a means to model disease spread mechanisms and understand how one can best control the disease in case an outbreak of a widespread epidemic occurs. However, a significant challenge within the community is in the development of approaches that can be used to rigorously verify and validate these models. In this paper, we present an approach to rigorously examine and verify the behavioral properties of compartmen- tal epidemiological models under several common modeling scenarios including birth/death rates and multi-host/pathogen species. Using metamorphic testing, a novel visualization tool and model checking, we buildmore » a workflow that provides insights into the functionality of compartmental epidemiological models. Our initial results indicate that metamorphic testing can be used to verify the implementation of these models and provide insights into special conditions where these mathematical models may fail. The visualization front-end allows the end-user to scan through a variety of parameters commonly used in these models to elucidate the conditions under which an epidemic can occur. Further, specifying these models using a process algebra allows one to automatically construct behavioral properties that can be rigorously verified using model checking. Taken together, our approach allows for detecting implementation errors as well as handling conditions under which compartmental epidemiological models may fail to provide insights into disease spread dynamics.« less

10 CFR 35.2642 - Records of periodic spot-checks for teletherapy units.

Code of Federal Regulations, 2010 CFR

2010-01-01

....2642 Section 35.2642 Energy NUCLEAR REGULATORY COMMISSION MEDICAL USE OF BYPRODUCT MATERIAL Records... must include— (1) The date of the spot-check; (2) The manufacturer's name, model number, and serial... device; (6) The determined accuracy of each distance measuring and localization device; (7) The...

10 CFR 35.2642 - Records of periodic spot-checks for teletherapy units.

Code of Federal Regulations, 2011 CFR

2011-01-01

....2642 Section 35.2642 Energy NUCLEAR REGULATORY COMMISSION MEDICAL USE OF BYPRODUCT MATERIAL Records... must include— (1) The date of the spot-check; (2) The manufacturer's name, model number, and serial... device; (6) The determined accuracy of each distance measuring and localization device; (7) The...

12 CFR Appendix A to Part 205 - Model Disclosure Clauses and Forms

Code of Federal Regulations, 2010 CFR

2010-01-01

... your checking account using information from your check to: (i) Pay for purchases. (ii) Pay bills. (3... disclose information to third parties about your account or the transfers you make: (i) Where it is...) Disclosure by government agencies of information about obtaining account balances and account histories...

Using computer models to design gully erosion control structures for humid northern Ethiopia

USDA-ARS?s Scientific Manuscript database

Classic gully erosion control measures such as check dams have been unsuccessful in halting gully formation and growth in the humid northern Ethiopian highlands. Gullies are typically formed in vertisols and flow often bypasses the check dams as elevated groundwater tables make gully banks unstable....

Posterior Predictive Checks for Conditional Independence between Response Time and Accuracy

ERIC Educational Resources Information Center

Bolsinova, Maria; Tijmstra, Jesper

2016-01-01

Conditional independence (CI) between response time and response accuracy is a fundamental assumption of many joint models for time and accuracy used in educational measurement. In this study, posterior predictive checks (PPCs) are proposed for testing this assumption. These PPCs are based on three discrepancy measures reflecting different…

Building Program Verifiers from Compilers and Theorem Provers

DTIC Science & Technology

2015-05-14

Checking with SMT UFO • LLVM-based front-end (partially reused in SeaHorn) • Combines Abstract Interpretation with Interpolation-Based Model Checking • (no...assertions Counter-examples are long Hard to determine (from main) what is relevant Assertion Main 35 Building Verifiers from Comp and SMT Gurfinkel, 2015

Exploration of Effective Persuasive Strategies Used in Resisting Product Advertising: A Case Study of Adult Health Check-Ups.

PubMed

Tien, Han-Kuang; Chung, Wen

2018-05-10

This research addressed adults' health check-ups through the lens of Role Transportation Theory. This theory is applied to narrative advertising that lures adults into seeking health check-ups by causing audiences to empathize with the advertisement's character. This study explored the persuasive mechanism behind narrative advertising and reinforced the Protection Motivation Theory model. We added two key perturbation variables: optimistic bias and truth avoidance. To complete the verification hypothesis, we performed two experiments. In Experiment 1, we recruited 77 respondents online for testing. We used analyses of variance to verify the effectiveness of narrative and informative advertising. Then, in Experiment 2, we recruited 228 respondents to perform offline physical experiments and conducted a path analysis through structural equation modelling. The findings showed that narrative advertising positively impacted participants' disease prevention intentions. The use of Role Transportation Theory in advertising enables the audience to be emotionally connected with the character, which enhances persuasiveness. In Experiment 2, we found that the degree of role transference can interfere with optimistic bias, improve perceived health risk, and promote behavioral intentions for health check-ups. Furthermore, truth avoidance can interfere with perceived health risks, which, in turn, reduce behavioral intentions for health check-ups.

A rule-based approach to model checking of UML state machines

NASA Astrophysics Data System (ADS)

Grobelna, Iwona; Grobelny, Michał; Stefanowicz, Łukasz

2016-12-01

In the paper a new approach to formal verification of control process specification expressed by means of UML state machines in version 2.x is proposed. In contrast to other approaches from the literature, we use the abstract and universal rule-based logical model suitable both for model checking (using the nuXmv model checker), but also for logical synthesis in form of rapid prototyping. Hence, a prototype implementation in hardware description language VHDL can be obtained that fully reflects the primary, already formally verified specification in form of UML state machines. Presented approach allows to increase the assurance that implemented system meets the user-defined requirements.

Introduction of Virtualization Technology to Multi-Process Model Checking

NASA Technical Reports Server (NTRS)

Leungwattanakit, Watcharin; Artho, Cyrille; Hagiya, Masami; Tanabe, Yoshinori; Yamamoto, Mitsuharu

2009-01-01

Model checkers find failures in software by exploring every possible execution schedule. Java PathFinder (JPF), a Java model checker, has been extended recently to cover networked applications by caching data transferred in a communication channel. A target process is executed by JPF, whereas its peer process runs on a regular virtual machine outside. However, non-deterministic target programs may produce different output data in each schedule, causing the cache to restart the peer process to handle the different set of data. Virtualization tools could help us restore previous states of peers, eliminating peer restart. This paper proposes the application of virtualization technology to networked model checking, concentrating on JPF.

Body checking is associated with weight- and body-related shame and weight- and body-related guilt among men and women.

PubMed

Solomon-Krakus, Shauna; Sabiston, Catherine M

2017-12-01

This study examined whether body checking was a correlate of weight- and body-related shame and guilt for men and women. Participants were 537 adults (386 women) between the ages of 17 and 74 (M age =28.29, SD=14.63). Preliminary analyses showed women reported significantly more body-checking (p<.001), weight- and body-related shame (p<.001), and weight- and body-related guilt (p<.001) than men. In sex-stratified hierarchical linear regression models, body checking was significantly and positively associated with weight- and body-related shame (R 2 =.29 and .43, p<.001) and weight- and body-related guilt (R 2 =.34 and .45, p<.001) for men and women, respectively. Based on these findings, body checking is associated with negative weight- and body-related self-conscious emotions. Intervention and prevention efforts aimed at reducing negative weight- and body-related self-conscious emotions should consider focusing on body checking for adult men and women. Copyright © 2017 Elsevier Ltd. All rights reserved.

Practical Results from the Application of Model Checking and Test Generation from UML/SysML Models of On-Board Space Applications

NASA Astrophysics Data System (ADS)

Faria, J. M.; Mahomad, S.; Silva, N.

2009-05-01

The deployment of complex safety-critical applications requires rigorous techniques and powerful tools both for the development and V&V stages. Model-based technologies are increasingly being used to develop safety-critical software, and arguably, turning to them can bring significant benefits to such processes, however, along with new challenges. This paper presents the results of a research project where we tried to extend current V&V methodologies to be applied on UML/SysML models and aiming at answering the demands related to validation issues. Two quite different but complementary approaches were investigated: (i) model checking and the (ii) extraction of robustness test-cases from the same models. These two approaches don't overlap and when combined provide a wider reaching model/design validation ability than each one alone thus offering improved safety assurance. Results are very encouraging, even though they either fell short of the desired outcome as shown for model checking, or still appear as not fully matured as shown for robustness test case extraction. In the case of model checking, it was verified that the automatic model validation process can become fully operational and even expanded in scope once tool vendors help (inevitably) to improve the XMI standard interoperability situation. For the robustness test case extraction methodology, the early approach produced interesting results but need further systematisation and consolidation effort in order to produce results in a more predictable fashion and reduce reliance on expert's heuristics. Finally, further improvements and innovation research projects were immediately apparent for both investigated approaches, which point to either circumventing current limitations in XMI interoperability on one hand and bringing test case specification onto the same graphical level as the models themselves and then attempting to automate the generation of executable test cases from its standard UML notation.

An experimental manipulation of responsibility in children: a test of the inflated responsibility model of obsessive-compulsive disorder.

PubMed

Reeves, J; Reynolds, S; Coker, S; Wilson, C

2010-09-01

The objective of this study was to investigate whether Salkovskis (1985) inflated responsibility model of obsessive-compulsive disorder (OCD) applied to children. In an experimental design, 81 children aged 9-12 years were randomly allocated to three conditions: an inflated responsibility group, a moderate responsibility group, and a reduced responsibility group. In all groups children were asked to sort sweets according to whether or not they contained nuts. At baseline the groups did not differ on children's self reported anxiety, depression, obsessive-compulsive symptoms or on inflated responsibility beliefs. The experimental manipulation successfully changed children's perceptions of responsibility. During the sorting task time taken to complete the task, checking behaviours, hesitations, and anxiety were recorded. There was a significant effect of responsibility level on the behavioural variables of time taken, hesitations and check; as perceived responsibility increased children took longer to complete the task and checked and hesitated more often. There was no between-group difference in children's self reported state anxiety. The results offer preliminary support for the link between inflated responsibility and increased checking behaviours in children and add to the small but growing literature suggesting that cognitive models of OCD may apply to children. (c) 2010 Elsevier Ltd. All rights reserved.

75 FR 52482 - Airworthiness Directives; PILATUS Aircraft Ltd. Model PC-7 Airplanes

Federal Register 2010, 2011, 2012, 2013, 2014

2010-08-26

..., check the airplane maintenance records to determine if the left and/or right aileron outboard bearing... an entry is found during the airplane maintenance records check required in paragraph (f)(1) of this...-0849; Directorate Identifier 2010-CE-043-AD] RIN 2120-AA64 Airworthiness Directives; PILATUS Aircraft...

77 FR 50644 - Airworthiness Directives; Cessna Airplane Company Airplanes

Federal Register 2010, 2011, 2012, 2013, 2014

2012-08-22

... airplanes that have P/N 1134104-1 or 1134104-5 A/C compressor motor installed; an aircraft logbook check for... following: (1) Inspect the number of hours on the A/C compressor hour meter; and (2) Check the aircraft.... Do the replacement following Cessna Aircraft Company Model 525 Maintenance Manual, Revision 23, dated...

Design of experiments enhanced statistical process control for wind tunnel check standard testing

NASA Astrophysics Data System (ADS)

Phillips, Ben D.

The current wind tunnel check standard testing program at NASA Langley Research Center is focused on increasing data quality, uncertainty quantification and overall control and improvement of wind tunnel measurement processes. The statistical process control (SPC) methodology employed in the check standard testing program allows for the tracking of variations in measurements over time as well as an overall assessment of facility health. While the SPC approach can and does provide researchers with valuable information, it has certain limitations in the areas of process improvement and uncertainty quantification. It is thought by utilizing design of experiments methodology in conjunction with the current SPC practices that one can efficiently and more robustly characterize uncertainties and develop enhanced process improvement procedures. In this research, methodologies were developed to generate regression models for wind tunnel calibration coefficients, balance force coefficients and wind tunnel flow angularities. The coefficients of these regression models were then tracked in statistical process control charts, giving a higher level of understanding of the processes. The methodology outlined is sufficiently generic such that this research can be applicable to any wind tunnel check standard testing program.

CCM-C,Collins checks the middeck experiment

NASA Image and Video Library

1999-07-24

S93-E-5016 (23 July 1999) --- Astronaut Eileen M. Collins, mission commander, checks on an experiment on Columbia's middeck during Flight Day 1 activity. The experiment is called the Cell Culture Model, Configuration C. Objectives of it are to validate cell culture models for muscle, bone and endothelial cell biochemical and functional loss induced by microgravity stress; to evaluate cytoskeleton, metabolism, membrane integrity and protease activity in target cells; and to test tissue loss pharmaceuticals for efficacy. The photo was recorded with an electronic still camera (ESC).

Class Model Development Using Business Rules

NASA Astrophysics Data System (ADS)

Skersys, Tomas; Gudas, Saulius

New developments in the area of computer-aided system engineering (CASE) greatly improve processes of the information systems development life cycle (ISDLC). Much effort is put into the quality improvement issues, but IS development projects still suffer from the poor quality of models during the system analysis and design cycles. At some degree, quality of models that are developed using CASE tools can be assured using various. automated. model comparison, syntax. checking procedures. It. is also reasonable to check these models against the business domain knowledge, but the domain knowledge stored in the repository of CASE tool (enterprise model) is insufficient (Gudas et al. 2004). Involvement of business domain experts into these processes is complicated because non- IT people often find it difficult to understand models that were developed by IT professionals using some specific modeling language.

[Proposal and preliminary validation of a check-list for the assessment of occupational exposure to repetitive movements of the upper lims].

PubMed

Colombini, D; Occhipinti, E; Cairoli, S; Baracco, A

2000-01-01

Over the last few years the Authors developed and implemented, a specific check-list for a "rapid" assessment of occupational exposure to repetitive movements and exertion of the upper limbs, after verifying the lack of such a tool which also had to be coherent with the latest data in the specialized literature. The check-list model and the relevant application procedures are presented and discussed. The check-list was applied by trained factory technicians in 46 different working tasks where the OCRA method previously proposed by the Authors was also applied by independent observers. Since 46 pairs of observation data were available (OCRA index and check-list score) it was possible to verify, via parametric and nonparametric statistical tests, the level of association between the two variables and to find the best simple regression function (exponential in this case) of the OCRA index from the check-list score. By means of this function, which was highly significant (R2 = 0.98, p < 0.0000), the values of the check-list score which better corresponded to the critical values (for exposure assessment) of the OCRA index looked for. The following correspondance values between OCRA Index and check-list were then established with a view to classifying exposure levels. The check-list "critical" scores were established considering the need for obtaining, in borderline cases, a potential effect of overestimation of the exposure level. On the basis of practical application experience and the preliminary validation results, recommendations are made and the caution needed in the use of the check-list is suggested.

Socioeconomic differences in health check-ups and medically certified sickness absence: a 10-year follow-up among middle-aged municipal employees in Finland.

PubMed

Piha, Kustaa; Sumanen, Hilla; Lahelma, Eero; Rahkonen, Ossi

2017-04-01

There is contradictory evidence on the association between health check-ups and future morbidity. Among the general population, those with high socioeconomic position participate more often in health check-ups. The main aims of this study were to analyse if attendance to health check-ups are socioeconomically patterned and affect sickness absence over a 10-year follow-up. This register-based follow-up study included municipal employees of the City of Helsinki. 13 037 employees were invited to age-based health check-up during 2000-2002, with a 62% attendance rate. Education, occupational class and individual income were used to measure socioeconomic position. Medically certified sickness absence of 4 days or more was measured and controlled for at the baseline and used as an outcome over follow-up. The mean follow-up time was 7.5 years. Poisson regression was used. Men and employees with lower socioeconomic position participated more actively in health check-ups. Among women, non-attendance to health check-up predicted higher sickness absence during follow-up (relative risk =1.26, 95% CI 1.17 to 1.37) in the fully adjusted model. Health check-ups were not effective in reducing socioeconomic differences in sickness absence. Age-based health check-ups reduced subsequent sickness absence and should be promoted. Attendance to health check-ups should be as high as possible. Contextual factors need to be taken into account when applying the results in interventions in other settings. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/.

Runtime Verification of C Programs

NASA Technical Reports Server (NTRS)

Havelund, Klaus

2008-01-01

We present in this paper a framework, RMOR, for monitoring the execution of C programs against state machines, expressed in a textual (nongraphical) format in files separate from the program. The state machine language has been inspired by a graphical state machine language RCAT recently developed at the Jet Propulsion Laboratory, as an alternative to using Linear Temporal Logic (LTL) for requirements capture. Transitions between states are labeled with abstract event names and Boolean expressions over such. The abstract events are connected to code fragments using an aspect-oriented pointcut language similar to ASPECTJ's or ASPECTC's pointcut language. The system is implemented in the C analysis and transformation package CIL, and is programmed in OCAML, the implementation language of CIL. The work is closely related to the notion of stateful aspects within aspect-oriented programming, where pointcut languages are extended with temporal assertions over the execution trace.

Litho hotspots fixing using model based algorithm

NASA Astrophysics Data System (ADS)

Zhang, Meili; Yu, Shirui; Mao, Zhibiao; Shafee, Marwa; Madkour, Kareem; ElManhawy, Wael; Kwan, Joe; Hu, Xinyi; Wan, Qijian; Du, Chunshan

2017-04-01

As technology advances, IC designs are getting more sophisticated, thus it becomes more critical and challenging to fix printability issues in the design flow. Running lithography checks before tapeout is now mandatory for designers, which creates a need for more advanced and easy-to-use techniques for fixing hotspots found after lithographic simulation without creating a new design rule checking (DRC) violation or generating a new hotspot. This paper presents a new methodology for fixing hotspots on layouts while using the same engine currently used to detect the hotspots. The fix is achieved by applying minimum movement of edges causing the hotspot, with consideration of DRC constraints. The fix is internally simulated by the lithographic simulation engine to verify that the hotspot is eliminated and that no new hotspot is generated by the new edge locations. Hotspot fix checking is enhanced by adding DRC checks to the litho-friendly design (LFD) rule file to guarantee that any fix options that violate DRC checks are removed from the output hint file. This extra checking eliminates the need to re-run both DRC and LFD checks to ensure the change successfully fixed the hotspot, which saves time and simplifies the designer's workflow. This methodology is demonstrated on industrial designs, where the fixing rate of single and dual layer hotspots is reported.

Model-Checking with Edge-Valued Decision Diagrams

NASA Technical Reports Server (NTRS)

Roux, Pierre; Siminiceanu, Radu I.

2010-01-01

We describe an algebra of Edge-Valued Decision Diagrams (EVMDDs) to encode arithmetic functions and its implementation in a model checking library along with state-of-the-art algorithms for building the transition relation and the state space of discrete state systems. We provide efficient algorithms for manipulating EVMDDs and give upper bounds of the theoretical time complexity of these algorithms for all basic arithmetic and relational operators. We also demonstrate that the time complexity of the generic recursive algorithm for applying a binary operator on EVMDDs is no worse than that of Multi-Terminal Decision Diagrams. We have implemented a new symbolic model checker with the intention to represent in one formalism the best techniques available at the moment across a spectrum of existing tools: EVMDDs for encoding arithmetic expressions, identity-reduced MDDs for representing the transition relation, and the saturation algorithm for reachability analysis. We compare our new symbolic model checking EVMDD library with the widely used CUDD package and show that, in many cases, our tool is several orders of magnitude faster than CUDD.

Assume-Guarantee Verification of Source Code with Design-Level Assumptions

NASA Technical Reports Server (NTRS)

Giannakopoulou, Dimitra; Pasareanu, Corina S.; Cobleigh, Jamieson M.

2004-01-01

Model checking is an automated technique that can be used to determine whether a system satisfies certain required properties. To address the 'state explosion' problem associated with this technique, we propose to integrate assume-guarantee verification at different phases of system development. During design, developers build abstract behavioral models of the system components and use them to establish key properties of the system. To increase the scalability of model checking at this level, we have developed techniques that automatically decompose the verification task by generating component assumptions for the properties to hold. The design-level artifacts are subsequently used to guide the implementation of the system, but also to enable more efficient reasoning at the source code-level. In particular we propose to use design-level assumptions to similarly decompose the verification of the actual system implementation. We demonstrate our approach on a significant NASA application, where design-level models were used to identify; and correct a safety property violation, and design-level assumptions allowed us to check successfully that the property was presented by the implementation.

Social-cognitive determinants of the tick check: a cross-sectional study on self-protective behavior in combatting Lyme disease.

PubMed

van der Heijden, Amy; Mulder, Bob C; Poortvliet, P Marijn; van Vliet, Arnold J H

2017-11-25

Performing a tick check after visiting nature is considered the most important preventive measure to avoid contracting Lyme disease. Checking the body for ticks after visiting nature is the only measure that can fully guarantee whether one has been bitten by a tick and provides the opportunity to remove the tick as soon as possible, thereby greatly reducing the chance of contracting Lyme disease. However, compliance to performing the tick check is low. In addition, most previous studies on determinants of preventive measures to avoid Lyme disease lack a clear definition and/or operationalization of the term "preventive measures". Those that do distinguish multiple behaviors including the tick check, fail to describe the systematic steps that should be followed in order to perform the tick check effectively. Hence, the purpose of this study was to identify determinants of systematically performing the tick check, based on social cognitive theory. A cross-sectional self-administered survey questionnaire was filled out online by 508 respondents (M age  = 51.7, SD = 16.0; 50.2% men; 86.4% daily or weekly nature visitors). Bivariate correlations and multivariate regression analyses were conducted to identify associations between socio-cognitive determinants (i.e. concepts related to humans' intrinsic and extrinsic motivation to perform certain behavior), and the tick check, and between socio-cognitive determinants and proximal goal to do the tick check. The full regression model explained 28% of the variance in doing the tick check. Results showed that performing the tick check was associated with proximal goal (β = .23, p < 0.01), self-efficacy (β = .22, p < 0.01), self-evaluative outcome expectations (β = .21, p < 0.01), descriptive norm (β = .16, p < 0.01), and experience (β = .13, p < 0.01). Our study is among the first to examine the determinants of systematic performance of the tick check, using an extended version of social cognitive theory to identify determinants. Based on the results, a number of practical recommendations can be made to promote the performance of the tick check.

Prediction Interval Development for Wind-Tunnel Balance Check-Loading

NASA Technical Reports Server (NTRS)

Landman, Drew; Toro, Kenneth G.; Commo, Sean A.; Lynn, Keith C.

2014-01-01

Results from the Facility Analysis Verification and Operational Reliability project revealed a critical gap in capability in ground-based aeronautics research applications. Without a standardized process for check-loading the wind-tunnel balance or the model system, the quality of the aerodynamic force data collected varied significantly between facilities. A prediction interval is required in order to confirm a check-loading. The prediction interval provides an expected upper and lower bound on balance load prediction at a given confidence level. A method has been developed which accounts for sources of variability due to calibration and check-load application. The prediction interval method of calculation and a case study demonstrating its use is provided. Validation of the methods is demonstrated for the case study based on the probability of capture of confirmation points.

75 FR 43801 - Airworthiness Directives; Eurocopter France (ECF) Model EC225LP Helicopters

Federal Register 2010, 2011, 2012, 2013, 2014

2010-07-27

... time. Also, we use inspect rather than check when referring to an action required by a mechanic as... the various levels of government. Therefore, I certify this AD: 1. Is not a ``significant regulatory... compliance time. Also, we use inspect rather than check when referring to an action required by a mechanic as...

Mandatory Identification Bar Checks: How Bouncers Are Doing Their Job

ERIC Educational Resources Information Center

Monk-Turner, Elizabeth; Allen, John; Casten, John; Cowling, Catherine; Gray, Charles; Guhr, David; Hoofnagle, Kara; Huffman, Jessica; Mina, Moises; Moore, Brian

2011-01-01

The behavior of bouncers at on site establishments that served alcohol was observed. Our aim was to better understand how bouncers went about their job when the bar had a mandatory policy to check identification of all customers. Utilizing an ethnographic decision model, we found that bouncers were significantly more likely to card customers that…

Enhancing Classroom Management Using the Classroom Check-up Consultation Model with In-Vivo Coaching and Goal Setting Components

ERIC Educational Resources Information Center

Kleinert, Whitney L.; Silva, Meghan R.; Codding, Robin S.; Feinberg, Adam B.; St. James, Paula S.

2017-01-01

Classroom management is essential to promote learning in schools, and as such it is imperative that teachers receive adequate support to maximize their competence implementing effective classroom management strategies. One way to improve teachers' classroom managerial competence is through consultation. The Classroom Check-Up (CCU) is a structured…

76 FR 18964 - Airworthiness Directives; Costruzioni Aeronautiche Tecnam srl Model P2006T Airplanes

Federal Register 2010, 2011, 2012, 2013, 2014

2011-04-06

... Landing Gear retraction/extension ground checks performed on the P2006T, a loose Seeger ring was found on... condition for the specified products. The MCAI states: During Landing Gear retraction/extension ground... retraction/extension ground checks performed on the P2006T, a loose Seeger ring was found on the nose landing...

78 FR 69987 - Airworthiness Directives; Erickson Air-Crane Incorporated Helicopters (Type Certificate...

Federal Register 2010, 2011, 2012, 2013, 2014

2013-11-22

... to require recurring checks of the Blade Inspection Method (BIM) indicator on each blade to determine whether the BIM indicator is signifying that the blade pressure may have been compromised by a blade crack... check procedures for BIM blades installed on the Model S-64E and S-64F helicopters. Several blade spars...

Motivational Interviewing for Effective Classroom Management: The Classroom Check-Up. Practical Intervention in the Schools Series

ERIC Educational Resources Information Center

Reinke, Wendy M.; Herman, Keith C.; Sprick, Randy

2011-01-01

Highly accessible and user-friendly, this book focuses on helping K-12 teachers increase their use of classroom management strategies that work. It addresses motivational aspects of teacher consultation that are essential, yet often overlooked. The Classroom Check-Up is a step-by-step model for assessing teachers' organizational, instructional,…

75 FR 63045 - Airworthiness Directives; BAE SYSTEMS (OPERATIONS) LIMITED Model BAe 146 and Avro 146-RJ Airplanes

Federal Register 2010, 2011, 2012, 2013, 2014

2010-10-14

... the fitting and wing structure. Checking the nuts with a suitable torque spanner to the specifications in the torque figures shown in Table 2. of the Accomplishment Instructions of BAE SYSTEMS (OPERATIONS... installed, and Doing either an ultrasonic inspection for damaged bolts or torque check of the tension bolts...

76 FR 13069 - Airworthiness Directives; BAE Systems (Operations) Limited Model ATP Airplanes; BAE Systems...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-03-10

..., an operator found an aileron trim tab hinge pin that had migrated sufficiently to cause a rubbing.... Recently, during a walk round check, an operator found an aileron trim tab hinge pin that had migrated... walk round check, an operator found an aileron trim tab hinge pin that had migrated sufficiently to...

Model Checking a Byzantine-Fault-Tolerant Self-Stabilizing Protocol for Distributed Clock Synchronization Systems

NASA Technical Reports Server (NTRS)

Malekpour, Mahyar R.

2007-01-01

This report presents the mechanical verification of a simplified model of a rapid Byzantine-fault-tolerant self-stabilizing protocol for distributed clock synchronization systems. This protocol does not rely on any assumptions about the initial state of the system. This protocol tolerates bursts of transient failures, and deterministically converges within a time bound that is a linear function of the self-stabilization period. A simplified model of the protocol is verified using the Symbolic Model Verifier (SMV) [SMV]. The system under study consists of 4 nodes, where at most one of the nodes is assumed to be Byzantine faulty. The model checking effort is focused on verifying correctness of the simplified model of the protocol in the presence of a permanent Byzantine fault as well as confirmation of claims of determinism and linear convergence with respect to the self-stabilization period. Although model checking results of the simplified model of the protocol confirm the theoretical predictions, these results do not necessarily confirm that the protocol solves the general case of this problem. Modeling challenges of the protocol and the system are addressed. A number of abstractions are utilized in order to reduce the state space. Also, additional innovative state space reduction techniques are introduced that can be used in future verification efforts applied to this and other protocols.

Stochastic Local Search for Core Membership Checking in Hedonic Games

NASA Astrophysics Data System (ADS)

Keinänen, Helena

Hedonic games have emerged as an important tool in economics and show promise as a useful formalism to model multi-agent coalition formation in AI as well as group formation in social networks. We consider a coNP-complete problem of core membership checking in hedonic coalition formation games. No previous algorithms to tackle the problem have been presented. In this work, we overcome this by developing two stochastic local search algorithms for core membership checking in hedonic games. We demonstrate the usefulness of the algorithms by showing experimentally that they find solutions efficiently, particularly for large agent societies.

Robust check loss-based variable selection of high-dimensional single-index varying-coefficient model

NASA Astrophysics Data System (ADS)

Song, Yunquan; Lin, Lu; Jian, Ling

2016-07-01

Single-index varying-coefficient model is an important mathematical modeling method to model nonlinear phenomena in science and engineering. In this paper, we develop a variable selection method for high-dimensional single-index varying-coefficient models using a shrinkage idea. The proposed procedure can simultaneously select significant nonparametric components and parametric components. Under defined regularity conditions, with appropriate selection of tuning parameters, the consistency of the variable selection procedure and the oracle property of the estimators are established. Moreover, due to the robustness of the check loss function to outliers in the finite samples, our proposed variable selection method is more robust than the ones based on the least squares criterion. Finally, the method is illustrated with numerical simulations.

Model Checking Satellite Operational Procedures

NASA Astrophysics Data System (ADS)

Cavaliere, Federico; Mari, Federico; Melatti, Igor; Minei, Giovanni; Salvo, Ivano; Tronci, Enrico; Verzino, Giovanni; Yushtein, Yuri

2011-08-01

We present a model checking approach for the automatic verification of satellite operational procedures (OPs). Building a model for a complex system as a satellite is a hard task. We overcome this obstruction by using a suitable simulator (SIMSAT) for the satellite. Our approach aims at improving OP quality assurance by automatic exhaustive exploration of all possible simulation scenarios. Moreover, our solution decreases OP verification costs by using a model checker (CMurphi) to automatically drive the simulator. We model OPs as user-executed programs observing the simulator telemetries and sending telecommands to the simulator. In order to assess feasibility of our approach we present experimental results on a simple meaningful scenario. Our results show that we can save up to 90% of verification time.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Nakaguchi, Yuji, E-mail: nkgc2003@yahoo.co.jp; Ono, Takeshi; Onitsuka, Ryota

COMPASS system (IBA Dosimetry, Schwarzenbruck, Germany) and ArcCHECK with 3DVH software (Sun Nuclear Corp., Melbourne, FL) are commercial quasi-3-dimensional (3D) dosimetry arrays. Cross-validation to compare them under the same conditions, such as a treatment plan, allows for clear evaluation of such measurement devices. In this study, we evaluated the accuracy of reconstructed dose distributions from the COMPASS system and ArcCHECK with 3DVH software using Monte Carlo simulation (MC) for multi-leaf collimator (MLC) test patterns and clinical VMAT plans. In a phantom study, ArcCHECK 3DVH showed clear differences from COMPASS, measurement and MC due to the detector resolution and the dosemore » reconstruction method. Especially, ArcCHECK 3DVH showed 7% difference from MC for the heterogeneous phantom. ArcCHECK 3DVH only corrects the 3D dose distribution of treatment planning system (TPS) using ArcCHECK measurement, and therefore the accuracy of ArcCHECK 3DVH depends on TPS. In contrast, COMPASS showed good agreement with MC for all cases. However, the COMPASS system requires many complicated installation procedures such as beam modeling, and appropriate commissioning is needed. In terms of clinical cases, there were no large differences for each QA device. The accuracy of the compass and ArcCHECK 3DVH systems for phantoms and clinical cases was compared. Both systems have advantages and disadvantages for clinical use, and consideration of the operating environment is important. The QA system selection is depending on the purpose and workflow in each hospital.« less

Model Checking Abstract PLEXIL Programs with SMART

NASA Technical Reports Server (NTRS)

Siminiceanu, Radu I.

2007-01-01

We describe a method to automatically generate discrete-state models of abstract Plan Execution Interchange Language (PLEXIL) programs that can be analyzed using model checking tools. Starting from a high-level description of a PLEXIL program or a family of programs with common characteristics, the generator lays the framework that models the principles of program execution. The concrete parts of the program are not automatically generated, but require the modeler to introduce them by hand. As a case study, we generate models to verify properties of the PLEXIL macro constructs that are introduced as shorthand notation. After an exhaustive analysis, we conclude that the macro definitions obey the intended semantics and behave as expected, but contingently on a few specific requirements on the timing semantics of micro-steps in the concrete executive implementation.

Degummed crude canola oil, sire breed and gender effects on intramuscular long-chain omega-3 fatty acid properties of raw and cooked lamb meat.

PubMed

Flakemore, Aaron Ross; Malau-Aduli, Bunmi Sherifat; Nichols, Peter David; Malau-Aduli, Aduli Enoch Othniel

2017-01-01

Omega-3 long-chain (≥C 20 ) polyunsaturated fatty acids (ω3 LC-PUFA) confer important attributes to health-conscious meat consumers due to the significant role they play in brain development, prevention of coronary heart disease, obesity and hypertension. In this study, the ω3 LC-PUFA content of raw and cooked Longissimus thoracis et lumborum (LTL) muscle from genetically divergent Australian prime lambs supplemented with dietary degummed crude canola oil (DCCO) was evaluated. Samples of LTL muscle were sourced from 24 first cross ewe and wether lambs sired by Dorset, White Suffolk and Merino rams joined to Merino dams that were assigned to supplemental regimes of degummed crude canola oil (DCCO): a control diet at 0 mL/kg DM of DCCO (DCCOC); 25 mL/kg DM of DCCO (DCCOM) and 50 mL/kg DCCO (DCCOH). Lambs were individually housed and offered 1 kg/day/head for 42 days before being slaughtered. Samples for cooked analysis were prepared to a core temperature of 70 °C using conductive dry-heat. Within raw meats: DCCOH supplemented lambs had significantly ( P  < 0.05) higher concentrations of eicosapentaenoic (EPA, 20:5ω3) and EPA + docosahexaenoic (DHA, 22:6ω3) acids than those supplemented with DCCOM or DCCOC; Dorset sired lambs contained significantly ( P  < 0.05) more EPA and EPA + DHA than other sire breeds; diet and sire breed interactions were significant ( P  < 0.05) in affecting EPA and EPA + DHA concentrations. In cooked meat, ω3 LC-PUFA concentrations in DCCOM (32 mg/100 g), DCCOH (38 mg/100 g), Dorset (36 mg/100 g), White Suffolk (32 mg/100 g), ewes (32 mg/100 g) and wethers (33 mg/100 g), all exceeded the minimum content of 30 mg/100 g of edible cooked portion of EPA + DHA for Australian defined 'source' level ω3 LC-PUFA classification. These results present that combinations of dietary degummed crude canola oil, sheep genetics and culinary preparation method can be used as effective management tools to deliver nutritionally improved ω3 LC-PUFA lamb to meat consumers.

Lectin binding profiles of SSEA-4 enriched, pluripotent human embryonic stem cell surfaces

PubMed Central

Venable, Alison; Mitalipova, Maisam; Lyons, Ian; Jones, Karen; Shin, Soojung; Pierce, Michael; Stice, Steven

2005-01-01

Background Pluripotent human embryonic stem cells (hESCs) have the potential to form every cell type in the body. These cells must be appropriately characterized prior to differentiation studies or when defining characteristics of the pluripotent state. Some developmentally regulated cell surface antigens identified by monoclonal antibodies in a variety of species and stem cell types have proven to be side chains of membrane glycolipids and glycoproteins. Therefore, to examine hESC surfaces for other potential pluripotent markers, we used a panel of 14 lectins, which were chosen based on their specificity for a variety of carbohydrates and carbohydrate linkages, along with stage specific embryonic antigen-4 (SSEA-4), to determine binding quantitation by flow cytometry and binding localization in adherent colonies by immunocytochemistry. Results Enriching cells for SSEA-4 expression increased the percentage of SSEA-4 positive cells to 98–99%. Using enriched high SSEA-4-expressing hESCs, we then analyzed the binding percentages of selected lectins and found a large variation in binding percentages ranging from 4% to 99% binding. Lycopersicon (tomato)esculetum lectin (TL), Ricinus communis agglutinin (RCA), and Concanavalin A (Con A) bound to SSEA-4 positive regions of hESCs and with similar binding percentages as SSEA-4. In contrast, we found Dolichos biflorus agglutinin (DBA) and Lotus tetragonolobus lectin (LTL) did not bind to hESCs while Phaseolus vulgaris leuco-agglutinin (PHA-L), Vicia villosa agglutinin (VVA), Ulex europaeus agglutinin (UEA), Phaseolus vulgaris erythro-agglutinin (PHA-E), and Maackia amurensis agglutinin (MAA) bound partially to hESCs. These binding percentages correlated well with immunocytochemistry results. Conclusion Our results provide information about types of carbohydrates and carbohydrate linkages found on pluripotent hESC surfaces. We propose that TL, RCA and Con A may be used as markers that are associated with the pluripotent state of hESCs because binding percentages and binding localization of these lectins are similar to those of SSEA-4. Non-binding lectins, DBA and LTL, may identify differentiated cell types; however, we did not find these lectins to bind to pluripotent SSEA-4 positive hESCs. This work represents a fundamental base to systematically classify pluripotent hESCs, and in future studies these lectins may be used to distinguish differentiated hESC types based on glycan presentation that accompanies differentiation. PMID:16033656

In ovo feeding with minerals and vitamin D3 improves bone properties in hatchlings and mature broilers.

PubMed

Yair, R; Shahar, R; Uni, Z

2015-11-01

The objective of this study was to examine the effect of in ovo feeding (IOF) with inorganic minerals or organic minerals and vitamin D3 on bone properties and mineral consumption. Eggs were incubated and divided into 4 groups: IOF with organic minerals, phosphate, and vitamin D3 (IOF-OMD); IOF with inorganic minerals and phosphate (IOF-IM); sham; and non-treated controls (NTC). IOF was performed on embryonic day (E) 17; tibiae and yolk samples were taken on E19 and E21. Post-hatch, only chicks from the IOF-OMD, sham, and NTC were raised, and tibiae were taken on d 10 and 38. Yolk mineral content was examined by inductively coupled plasma spectroscopy. Tibiae were tested for their whole-bone mechanical properties, and mid-diaphysis bone sections were indented in a micro-indenter to determine bone material stiffness (Young's modulus). Micro-computed tomography (μCT) was used to examine cortical and trabecular bone structure. Ash content analysis was used to examine bone mineralization. A latency-to-lie (LTL) test was used to measure standing ability of the d 38 broilers. The results showed that embryos from both IOF-OMD and IOF-IM treatments had elevated Cu, Mn, and Zn amounts in the yolk on E19 and E21 and consumed more of these minerals (between E19 and E21) in comparison to the sham and NTC. On E21, these hatchlings had higher whole-bone stiffness in comparison to the NTC. On d 38, the IOF-OMD had higher ash content, elevated whole-bone stiffness, and elevated Young's modulus (in males) in comparison to the sham and NTC; however, no differences in standing ability were found. Very few structural differences were seen during the whole experiment. This study demonstrates that mineral supplementation by in ovo feeding is sufficient to induce higher mineral consumption from the yolk, regardless of its chemical form or the presence of vitamin D3. Additionally, IOF with organic minerals and vitamin D3 can increase bone ash content, as well as stiffness of the whole bone and bone material in the mature broiler, but does not lead to longer LTL. © 2015 Poultry Science Association Inc.

An approach to checking case-crossover analyses based on equivalence with time-series methods.

PubMed

Lu, Yun; Symons, James Morel; Geyh, Alison S; Zeger, Scott L

2008-03-01

The case-crossover design has been increasingly applied to epidemiologic investigations of acute adverse health effects associated with ambient air pollution. The correspondence of the design to that of matched case-control studies makes it inferentially appealing for epidemiologic studies. Case-crossover analyses generally use conditional logistic regression modeling. This technique is equivalent to time-series log-linear regression models when there is a common exposure across individuals, as in air pollution studies. Previous methods for obtaining unbiased estimates for case-crossover analyses have assumed that time-varying risk factors are constant within reference windows. In this paper, we rely on the connection between case-crossover and time-series methods to illustrate model-checking procedures from log-linear model diagnostics for time-stratified case-crossover analyses. Additionally, we compare the relative performance of the time-stratified case-crossover approach to time-series methods under 3 simulated scenarios representing different temporal patterns of daily mortality associated with air pollution in Chicago, Illinois, during 1995 and 1996. Whenever a model-be it time-series or case-crossover-fails to account appropriately for fluctuations in time that confound the exposure, the effect estimate will be biased. It is therefore important to perform model-checking in time-stratified case-crossover analyses rather than assume the estimator is unbiased.

Bounded Parametric Model Checking for Elementary Net Systems

NASA Astrophysics Data System (ADS)

Knapik, Michał; Szreter, Maciej; Penczek, Wojciech

Bounded Model Checking (BMC) is an efficient verification method for reactive systems. BMC has been applied so far to verification of properties expressed in (timed) modal logics, but never to their parametric extensions. In this paper we show, for the first time that BMC can be extended to PRTECTL - a parametric extension of the existential version of CTL. To this aim we define a bounded semantics and a translation from PRTECTL to SAT. The implementation of the algorithm for Elementary Net Systems is presented, together with some experimental results.

The instant sequencing task: Toward constraint-checking a complex spacecraft command sequence interactively

NASA Technical Reports Server (NTRS)

Horvath, Joan C.; Alkalaj, Leon J.; Schneider, Karl M.; Amador, Arthur V.; Spitale, Joseph N.

1993-01-01

Robotic spacecraft are controlled by sets of commands called 'sequences.' These sequences must be checked against mission constraints. Making our existing constraint checking program faster would enable new capabilities in our uplink process. Therefore, we are rewriting this program to run on a parallel computer. To do so, we had to determine how to run constraint-checking algorithms in parallel and create a new method of specifying spacecraft models and constraints. This new specification gives us a means of representing flight systems and their predicted response to commands which could be used in a variety of applications throughout the command process, particularly during anomaly or high-activity operations. This commonality could reduce operations cost and risk for future complex missions. Lessons learned in applying some parts of this system to the TOPEX/Poseidon mission will be described.

Evaluating and Improving a Learning Trajectory for Linear Measurement in Elementary Grades 2 and 3: A Longitudinal Study

ERIC Educational Resources Information Center

Barrett, Jeffrey E.; Sarama, Julie; Clements, Douglas H.; Cullen, Craig; McCool, Jenni; Witkowski-Rumsey, Chepina; Klanderman, David

2012-01-01

We examined children's development of strategic and conceptual knowledge for linear measurement. We conducted teaching experiments with eight students in grades 2 and 3, based on our hypothetical learning trajectory for length to check its coherence and to strengthen the domain-specific model for learning and teaching. We checked the hierarchical…

75 FR 39185 - Airworthiness Directives; The Boeing Company Model 747-100, 747-100B, 747-100B SUD, 747-200B, 747...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-07-08

... and torque checks of the hanger fittings and strut forward bulkhead of the forward engine mount and... requires repetitive inspections and torque checks of the hanger fittings and strut forward bulkhead of the... corrective actions are replacing the fasteners; removing loose fasteners; tightening all Group A [[Page 39187...

Visual Predictive Check in Models with Time-Varying Input Function.

PubMed

Largajolli, Anna; Bertoldo, Alessandra; Campioni, Marco; Cobelli, Claudio

2015-11-01

The nonlinear mixed effects models are commonly used modeling techniques in the pharmaceutical research as they enable the characterization of the individual profiles together with the population to which the individuals belong. To ensure a correct use of them is fundamental to provide powerful diagnostic tools that are able to evaluate the predictive performance of the models. The visual predictive check (VPC) is a commonly used tool that helps the user to check by visual inspection if the model is able to reproduce the variability and the main trend of the observed data. However, the simulation from the model is not always trivial, for example, when using models with time-varying input function (IF). In this class of models, there is a potential mismatch between each set of simulated parameters and the associated individual IF which can cause an incorrect profile simulation. We introduce a refinement of the VPC by taking in consideration a correlation term (the Mahalanobis or normalized Euclidean distance) that helps the association of the correct IF with the individual set of simulated parameters. We investigate and compare its performance with the standard VPC in models of the glucose and insulin system applied on real and simulated data and in a simulated pharmacokinetic/pharmacodynamic (PK/PD) example. The newly proposed VPC performance appears to be better with respect to the standard VPC especially for the models with big variability in the IF where the probability of simulating incorrect profiles is higher.

Model Checker for Java Programs

NASA Technical Reports Server (NTRS)

Visser, Willem

2007-01-01

Java Pathfinder (JPF) is a verification and testing environment for Java that integrates model checking, program analysis, and testing. JPF consists of a custom-made Java Virtual Machine (JVM) that interprets bytecode, combined with a search interface to allow the complete behavior of a Java program to be analyzed, including interleavings of concurrent programs. JPF is implemented in Java, and its architecture is highly modular to support rapid prototyping of new features. JPF is an explicit-state model checker, because it enumerates all visited states and, therefore, suffers from the state-explosion problem inherent in analyzing large programs. It is suited to analyzing programs less than 10kLOC, but has been successfully applied to finding errors in concurrent programs up to 100kLOC. When an error is found, a trace from the initial state to the error is produced to guide the debugging. JPF works at the bytecode level, meaning that all of Java can be model-checked. By default, the software checks for all runtime errors (uncaught exceptions), assertions violations (supports Java s assert), and deadlocks. JPF uses garbage collection and symmetry reductions of the heap during model checking to reduce state-explosion, as well as dynamic partial order reductions to lower the number of interleavings analyzed. JPF is capable of symbolic execution of Java programs, including symbolic execution of complex data such as linked lists and trees. JPF is extensible as it allows for the creation of listeners that can subscribe to events during searches. The creation of dedicated code to be executed in place of regular classes is supported and allows users to easily handle native calls and to improve the efficiency of the analysis.

Combining Static Analysis and Model Checking for Software Analysis

NASA Technical Reports Server (NTRS)

Brat, Guillaume; Visser, Willem; Clancy, Daniel (Technical Monitor)

2003-01-01

We present an iterative technique in which model checking and static analysis are combined to verify large software systems. The role of the static analysis is to compute partial order information which the model checker uses to reduce the state space. During exploration, the model checker also computes aliasing information that it gives to the static analyzer which can then refine its analysis. The result of this refined analysis is then fed back to the model checker which updates its partial order reduction. At each step of this iterative process, the static analysis computes optimistic information which results in an unsafe reduction of the state space. However we show that the process converges to a fired point at which time the partial order information is safe and the whole state space is explored.

Neighborhood social capital is associated with participation in health checks of a general population: a multilevel analysis of a population-based lifestyle intervention- the Inter99 study.

PubMed

Bender, Anne Mette; Kawachi, Ichiro; Jørgensen, Torben; Pisinger, Charlotta

2015-07-22

Participation in population-based preventive health check has declined over the past decades. More research is needed to determine factors enhancing participation. The objective of this study was to examine the association between two measures of neighborhood level social capital on participation in the health check phase of a population-based lifestyle intervention. The study population comprised 12,568 residents of 73 Danish neighborhoods in the intervention group of a large population-based lifestyle intervention study - the Inter99. Two measures of social capital were applied; informal socializing and voting turnout. In a multilevel analysis only adjusting for age and sex, a higher level of neighborhood social capital was associated with higher probability of participating in the health check. Inclusion of both individual socioeconomic position and neighborhood deprivation in the model attenuated the coefficients for informal socializing, while voting turnout became non-significant. Higher level of neighborhood social capital was associated with higher probability of participating in the health check phase of a population-based lifestyle intervention. Most of the association between neighborhood social capital and participation in preventive health checks can be explained by differences in individual socioeconomic position and level of neighborhood deprivation. Nonetheless, there seems to be some residual association between social capital and health check participation, suggesting that activating social relations in the community may be an avenue for boosting participation rates in population-based health checks. ClinicalTrials.gov (registration no. NCT00289237 ).

Microscopic analysis and simulation of check-mark stain on the galvanized steel strip

NASA Astrophysics Data System (ADS)

So, Hongyun; Yoon, Hyun Gi; Chung, Myung Kyoon

2010-11-01

When galvanized steel strip is produced through a continuous hot-dip galvanizing process, the thickness of adhered zinc film is controlled by plane impinging air gas jet referred to as "air-knife system". In such a gas-jet wiping process, stain of check-mark or sag line shape frequently appears. The check-mark defect is caused by non-uniform zinc coating and the oblique patterns such as "W", "V" or "X" on the coated surface. The present paper presents a cause and analysis of the check-mark formation and a numerical simulation of sag lines by using the numerical data produced by Large Eddy Simulation (LES) of the three-dimensional compressible turbulent flow field around the air-knife system. It was found that there is alternating plane-wise vortices near the impinging stagnation region and such alternating vortices move almost periodically to the right and to the left sides on the stagnation line due to the jet flow instability. Meanwhile, in order to simulate the check-mark formation, a novel perturbation model has been developed to predict the variation of coating thickness along the transverse direction. Finally, the three-dimensional zinc coating surface was obtained by the present perturbation model. It was found that the sag line formation is determined by the combination of the instantaneous coating thickness distribution along the transverse direction near the stagnation line and the feed speed of the steel strip.

Predictors of Health Service Utilization Among Older Men in Jamaica.

PubMed

Willie-Tyndale, Douladel; McKoy Davis, Julian; Holder-Nevins, Desmalee; Mitchell-Fearon, Kathryn; James, Kenneth; Waldron, Norman K; Eldemire-Shearer, Denise

2018-01-03

To determine the relative influence of sociodemographic, socioeconomic, psychosocial, and health variables on health service utilization in the last 12 months. Data were analyzed for 1,412 men ≥60 years old from a 2012 nationally representative community-based survey in Jamaica. Associations between six health service utilization variables and several explanatory variables were explored. Logistic regression models were used to identify independent predictors of each utilization measure and determine the strengths of associations. More than 75% reported having health visits and blood pressure checks. Blood sugar (69.6%) and cholesterol (63.1%) checks were less common, and having a prostate check (35.1%) was the least utilized service. Adjusted models confirmed that the presence of chronic diseases and health insurance most strongly predicted utilization. A daughter or son as the main source of financial support (vs self) doubled or tripled, respectively, the odds of routine doctors' visits. Compared with primary or lower education, tertiary education doubled [2.37 (1.12, 4.95)] the odds of a blood pressure check. Regular attendance at club/society/religious organizations' meetings increased the odds of having a prostate check by 45%. Although need and financial resources most strongly influenced health service utilization, psychosocial variables may be particularly influential for underutilized services. © The Author(s) 2018. Published by Oxford University Press on behalf of The Gerontological Society of America. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Simulation-based MDP verification for leading-edge masks

NASA Astrophysics Data System (ADS)

Su, Bo; Syrel, Oleg; Pomerantsev, Michael; Hagiwara, Kazuyuki; Pearman, Ryan; Pang, Leo; Fujimara, Aki

2017-07-01

For IC design starts below the 20nm technology node, the assist features on photomasks shrink well below 60nm and the printed patterns of those features on masks written by VSB eBeam writers start to show a large deviation from the mask designs. Traditional geometry-based fracturing starts to show large errors for those small features. As a result, other mask data preparation (MDP) methods have become available and adopted, such as rule-based Mask Process Correction (MPC), model-based MPC and eventually model-based MDP. The new MDP methods may place shot edges slightly differently from target to compensate for mask process effects, so that the final patterns on a mask are much closer to the design (which can be viewed as the ideal mask), especially for those assist features. Such an alteration generally produces better masks that are closer to the intended mask design. Traditional XOR-based MDP verification cannot detect problems caused by eBeam effects. Much like model-based OPC verification which became a necessity for OPC a decade ago, we see the same trend in MDP today. Simulation-based MDP verification solution requires a GPU-accelerated computational geometry engine with simulation capabilities. To have a meaningful simulation-based mask check, a good mask process model is needed. The TrueModel® system is a field tested physical mask model developed by D2S. The GPU-accelerated D2S Computational Design Platform (CDP) is used to run simulation-based mask check, as well as model-based MDP. In addition to simulation-based checks such as mask EPE or dose margin, geometry-based rules are also available to detect quality issues such as slivers or CD splits. Dose margin related hotspots can also be detected by setting a correct detection threshold. In this paper, we will demonstrate GPU-acceleration for geometry processing, and give examples of mask check results and performance data. GPU-acceleration is necessary to make simulation-based mask MDP verification acceptable.

Vehicular traffic noise prediction using soft computing approach.

PubMed

Singh, Daljeet; Nigam, S P; Agrawal, V P; Kumar, Maneek

2016-12-01

A new approach for the development of vehicular traffic noise prediction models is presented. Four different soft computing methods, namely, Generalized Linear Model, Decision Trees, Random Forests and Neural Networks, have been used to develop models to predict the hourly equivalent continuous sound pressure level, Leq, at different locations in the Patiala city in India. The input variables include the traffic volume per hour, percentage of heavy vehicles and average speed of vehicles. The performance of the four models is compared on the basis of performance criteria of coefficient of determination, mean square error and accuracy. 10-fold cross validation is done to check the stability of the Random Forest model, which gave the best results. A t-test is performed to check the fit of the model with the field data. Copyright © 2016 Elsevier Ltd. All rights reserved.

A generalized statistical model for the size distribution of wealth

NASA Astrophysics Data System (ADS)

Clementi, F.; Gallegati, M.; Kaniadakis, G.

2012-12-01

In a recent paper in this journal (Clementi et al 2009 J. Stat. Mech. P02037), we proposed a new, physically motivated, distribution function for modeling individual incomes, having its roots in the framework of the κ-generalized statistical mechanics. The performance of the κ-generalized distribution was checked against real data on personal income for the United States in 2003. In this paper we extend our previous model so as to be able to account for the distribution of wealth. Probabilistic functions and inequality measures of this generalized model for wealth distribution are obtained in closed form. In order to check the validity of the proposed model, we analyze the US household wealth distributions from 1984 to 2009 and conclude an excellent agreement with the data that is superior to any other model already known in the literature.

Timing analysis by model checking

NASA Technical Reports Server (NTRS)

Naydich, Dimitri; Guaspari, David

2000-01-01

The safety of modern avionics relies on high integrity software that can be verified to meet hard real-time requirements. The limits of verification technology therefore determine acceptable engineering practice. To simplify verification problems, safety-critical systems are commonly implemented under the severe constraints of a cyclic executive, which make design an expensive trial-and-error process highly intolerant of change. Important advances in analysis techniques, such as rate monotonic analysis (RMA), have provided a theoretical and practical basis for easing these onerous restrictions. But RMA and its kindred have two limitations: they apply only to verifying the requirement of schedulability (that tasks meet their deadlines) and they cannot be applied to many common programming paradigms. We address both these limitations by applying model checking, a technique with successful industrial applications in hardware design. Model checking algorithms analyze finite state machines, either by explicit state enumeration or by symbolic manipulation. Since quantitative timing properties involve a potentially unbounded state variable (a clock), our first problem is to construct a finite approximation that is conservative for the properties being analyzed-if the approximation satisfies the properties of interest, so does the infinite model. To reduce the potential for state space explosion we must further optimize this finite model. Experiments with some simple optimizations have yielded a hundred-fold efficiency improvement over published techniques.

Location contexts of user check-ins to model urban geo life-style patterns.

PubMed

Hasan, Samiul; Ukkusuri, Satish V

2015-01-01

Geo-location data from social media offers us information, in new ways, to understand people's attitudes and interests through their activity choices. In this paper, we explore the idea of inferring individual life-style patterns from activity-location choices revealed in social media. We present a model to understand life-style patterns using the contextual information (e. g. location categories) of user check-ins. Probabilistic topic models are developed to infer individual geo life-style patterns from two perspectives: i) to characterize the patterns of user interests to different types of places and ii) to characterize the patterns of user visits to different neighborhoods. The method is applied to a dataset of Foursquare check-ins of the users from New York City. The co-existence of several location contexts and the corresponding probabilities in a given pattern provide useful information about user interests and choices. It is found that geo life-style patterns have similar items-either nearby neighborhoods or similar location categories. The semantic and geographic proximity of the items in a pattern reflects the hidden regularity in user preferences and location choice behavior.

Constraint-Based Abstract Semantics for Temporal Logic: A Direct Approach to Design and Implementation

NASA Astrophysics Data System (ADS)

Banda, Gourinath; Gallagher, John P.

interpretation provides a practical approach to verifying properties of infinite-state systems. We apply the framework of abstract interpretation to derive an abstract semantic function for the modal μ-calculus, which is the basis for abstract model checking. The abstract semantic function is constructed directly from the standard concrete semantics together with a Galois connection between the concrete state-space and an abstract domain. There is no need for mixed or modal transition systems to abstract arbitrary temporal properties, as in previous work in the area of abstract model checking. Using the modal μ-calculus to implement CTL, the abstract semantics gives an over-approximation of the set of states in which an arbitrary CTL formula holds. Then we show that this leads directly to an effective implementation of an abstract model checking algorithm for CTL using abstract domains based on linear constraints. The implementation of the abstract semantic function makes use of an SMT solver. We describe an implemented system for proving properties of linear hybrid automata and give some experimental results.

76 FR 477 - Airworthiness Directives; Bombardier, Inc. Model CL-600-2A12 (CL-601) and CL-600-2B16 (CL-601-3A...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-01-05

... to these aircraft if Bombardier Service Bulletin (SB) 601-0590 [Scheduled Maintenance Instructions... information: Challenger 601 Time Limits/Maintenance Checks, PSP 601-5, Revision 38, dated June 19, 2009. Challenger 601 Time Limits/Maintenance Checks, PSP 601A-5, Revision 34, dated June 19, 2009. Challenger 604...

Model Checking with Edge-Valued Decision Diagrams

NASA Technical Reports Server (NTRS)

Roux, Pierre; Siminiceanu, Radu I.

2010-01-01

We describe an algebra of Edge-Valued Decision Diagrams (EVMDDs) to encode arithmetic functions and its implementation in a model checking library. We provide efficient algorithms for manipulating EVMDDs and review the theoretical time complexity of these algorithms for all basic arithmetic and relational operators. We also demonstrate that the time complexity of the generic recursive algorithm for applying a binary operator on EVMDDs is no worse than that of Multi- Terminal Decision Diagrams. We have implemented a new symbolic model checker with the intention to represent in one formalism the best techniques available at the moment across a spectrum of existing tools. Compared to the CUDD package, our tool is several orders of magnitude faster

Verification and Validation of Autonomy Software at NASA

NASA Technical Reports Server (NTRS)

Pecheur, Charles

2000-01-01

Autonomous software holds the promise of new operation possibilities, easier design and development and lower operating costs. However, as those system close control loops and arbitrate resources on board with specialized reasoning, the range of possible situations becomes very large and uncontrollable from the outside, making conventional scenario-based testing very inefficient. Analytic verification and validation (V&V) techniques, and model checking in particular, can provide significant help for designing autonomous systems in a more efficient and reliable manner, by providing a better coverage and allowing early error detection. This article discusses the general issue of V&V of autonomy software, with an emphasis towards model-based autonomy, model-checking techniques and concrete experiments at NASA.

Verification and Validation of Autonomy Software at NASA

NASA Technical Reports Server (NTRS)

Pecheur, Charles

2000-01-01

Autonomous software holds the promise of new operation possibilities, easier design and development, and lower operating costs. However, as those system close control loops and arbitrate resources on-board with specialized reasoning, the range of possible situations becomes very large and uncontrollable from the outside, making conventional scenario-based testing very inefficient. Analytic verification and validation (V&V) techniques, and model checking in particular, can provide significant help for designing autonomous systems in a more efficient and reliable manner, by providing a better coverage and allowing early error detection. This article discusses the general issue of V&V of autonomy software, with an emphasis towards model-based autonomy, model-checking techniques, and concrete experiments at NASA.

Combining Static Model Checking with Dynamic Enforcement Using the Statecall Policy Language

NASA Astrophysics Data System (ADS)

Madhavapeddy, Anil

Internet protocols encapsulate a significant amount of state, making implementing the host software complex. In this paper, we define the Statecall Policy Language (SPL) which provides a usable middle ground between ad-hoc coding and formal reasoning. It enables programmers to embed automata in their code which can be statically model-checked using SPIN and dynamically enforced. The performance overheads are minimal, and the automata also provide higher-level debugging capabilities. We also describe some practical uses of SPL by describing the automata used in an SSH server written entirely in OCaml/SPL.

Symbolic Analysis of Concurrent Programs with Polymorphism

NASA Technical Reports Server (NTRS)

Rungta, Neha Shyam

2010-01-01

The current trend of multi-core and multi-processor computing is causing a paradigm shift from inherently sequential to highly concurrent and parallel applications. Certain thread interleavings, data input values, or combinations of both often cause errors in the system. Systematic verification techniques such as explicit state model checking and symbolic execution are extensively used to detect errors in such systems [7, 9]. Explicit state model checking enumerates possible thread schedules and input data values of a program in order to check for errors [3, 9]. To partially mitigate the state space explosion from data input values, symbolic execution techniques substitute data input values with symbolic values [5, 7, 6]. Explicit state model checking and symbolic execution techniques used in conjunction with exhaustive search techniques such as depth-first search are unable to detect errors in medium to large-sized concurrent programs because the number of behaviors caused by data and thread non-determinism is extremely large. We present an overview of abstraction-guided symbolic execution for concurrent programs that detects errors manifested by a combination of thread schedules and data values [8]. The technique generates a set of key program locations relevant in testing the reachability of the target locations. The symbolic execution is then guided along these locations in an attempt to generate a feasible execution path to the error state. This allows the execution to focus in parts of the behavior space more likely to contain an error.

Diagnosis checking of statistical analysis in RCTs indexed in PubMed.

PubMed

Lee, Paul H; Tse, Andy C Y

2017-11-01

Statistical analysis is essential for reporting of the results of randomized controlled trials (RCTs), as well as evaluating their effectiveness. However, the validity of a statistical analysis also depends on whether the assumptions of that analysis are valid. To review all RCTs published in journals indexed in PubMed during December 2014 to provide a complete picture of how RCTs handle assumptions of statistical analysis. We reviewed all RCTs published in December 2014 that appeared in journals indexed in PubMed using the Cochrane highly sensitive search strategy. The 2014 impact factors of the journals were used as proxies for their quality. The type of statistical analysis used and whether the assumptions of the analysis were tested were reviewed. In total, 451 papers were included. Of the 278 papers that reported a crude analysis for the primary outcomes, 31 (27·2%) reported whether the outcome was normally distributed. Of the 172 papers that reported an adjusted analysis for the primary outcomes, diagnosis checking was rarely conducted, with only 20%, 8·6% and 7% checked for generalized linear model, Cox proportional hazard model and multilevel model, respectively. Study characteristics (study type, drug trial, funding sources, journal type and endorsement of CONSORT guidelines) were not associated with the reporting of diagnosis checking. The diagnosis of statistical analyses in RCTs published in PubMed-indexed journals was usually absent. Journals should provide guidelines about the reporting of a diagnosis of assumptions. © 2017 Stichting European Society for Clinical Investigation Journal Foundation.

Method-independent, Computationally Frugal Convergence Testing for Sensitivity Analysis Techniques

NASA Astrophysics Data System (ADS)

Mai, J.; Tolson, B.

2017-12-01

The increasing complexity and runtime of environmental models lead to the current situation that the calibration of all model parameters or the estimation of all of their uncertainty is often computationally infeasible. Hence, techniques to determine the sensitivity of model parameters are used to identify most important parameters. All subsequent model calibrations or uncertainty estimation procedures focus then only on these subsets of parameters and are hence less computational demanding. While the examination of the convergence of calibration and uncertainty methods is state-of-the-art, the convergence of the sensitivity methods is usually not checked. If any, bootstrapping of the sensitivity results is used to determine the reliability of the estimated indexes. Bootstrapping, however, might as well become computationally expensive in case of large model outputs and a high number of bootstraps. We, therefore, present a Model Variable Augmentation (MVA) approach to check the convergence of sensitivity indexes without performing any additional model run. This technique is method- and model-independent. It can be applied either during the sensitivity analysis (SA) or afterwards. The latter case enables the checking of already processed sensitivity indexes. To demonstrate the method's independency of the convergence testing method, we applied it to two widely used, global SA methods: the screening method known as Morris method or Elementary Effects (Morris 1991) and the variance-based Sobol' method (Solbol' 1993). The new convergence testing method is first scrutinized using 12 analytical benchmark functions (Cuntz & Mai et al. 2015) where the true indexes of aforementioned three methods are known. This proof of principle shows that the method reliably determines the uncertainty of the SA results when different budgets are used for the SA. The results show that the new frugal method is able to test the convergence and therefore the reliability of SA results in an efficient way. The appealing feature of this new technique is the necessity of no further model evaluation and therefore enables checking of already processed sensitivity results. This is one step towards reliable and transferable, published sensitivity results.

Neighborhood deprivation is strongly associated with participation in a population-based health check.

PubMed

Bender, Anne Mette; Kawachi, Ichiro; Jørgensen, Torben; Pisinger, Charlotta

2015-01-01

We sought to examine whether neighborhood deprivation is associated with participation in a large population-based health check. Such analyses will help answer the question whether health checks, which are designed to meet the needs of residents in deprived neighborhoods, may increase participation and prove to be more effective in preventing disease. In Europe, no study has previously looked at the association between neighborhood deprivation and participation in a population-based health check. The study population comprised 12,768 persons invited for a health check including screening for ischemic heart disease and lifestyle counseling. The study population was randomly drawn from a population of 179,097 persons living in 73 neighborhoods in Denmark. Data on neighborhood deprivation (percentage with basic education, with low income and not in work) and individual socioeconomic position were retrieved from national administrative registers. Multilevel regression analyses with log links and binary distributions were conducted to obtain relative risks, intraclass correlation coefficients and proportional change in variance. Large differences between neighborhoods existed in both deprivation levels and neighborhood health check participation rate (mean 53%; range 35-84%). In multilevel analyses adjusted for age and sex, higher levels of all three indicators of neighborhood deprivation and a deprivation score were associated with lower participation in a dose-response fashion. Persons living in the most deprived neighborhoods had up to 37% decreased probability of participating compared to those living in the least deprived neighborhoods. Inclusion of individual socioeconomic position in the model attenuated the neighborhood deprivation coefficients, but all except for income deprivation remained statistically significant. Neighborhood deprivation was associated with participation in a population-based health check in a dose-response manner, in which increasing neighborhood deprivation was associated with decreasing participation. This suggests the need to develop preventive health checks tailored to deprived neighborhoods.

Performance Evaluation of 3d Modeling Software for Uav Photogrammetry

NASA Astrophysics Data System (ADS)

Yanagi, H.; Chikatsu, H.

2016-06-01

UAV (Unmanned Aerial Vehicle) photogrammetry, which combines UAV and freely available internet-based 3D modeling software, is widely used as a low-cost and user-friendly photogrammetry technique in the fields such as remote sensing and geosciences. In UAV photogrammetry, only the platform used in conventional aerial photogrammetry is changed. Consequently, 3D modeling software contributes significantly to its expansion. However, the algorithms of the 3D modelling software are black box algorithms. As a result, only a few studies have been able to evaluate their accuracy using 3D coordinate check points. With this motive, Smart3DCapture and Pix4Dmapper were downloaded from the Internet and commercial software PhotoScan was also employed; investigations were performed in this paper using check points and images obtained from UAV.

CheckMyMetal: a macromolecular metal-binding validation tool

PubMed Central

Porebski, Przemyslaw J.

2017-01-01

Metals are essential in many biological processes, and metal ions are modeled in roughly 40% of the macromolecular structures in the Protein Data Bank (PDB). However, a significant fraction of these structures contain poorly modeled metal-binding sites. CheckMyMetal (CMM) is an easy-to-use metal-binding site validation server for macromolecules that is freely available at http://csgid.org/csgid/metal_sites. The CMM server can detect incorrect metal assignments as well as geometrical and other irregularities in the metal-binding sites. Guidelines for metal-site modeling and validation in macromolecules are illustrated by several practical examples grouped by the type of metal. These examples show CMM users (and crystallographers in general) problems they may encounter during the modeling of a specific metal ion. PMID:28291757

Method and system to perform energy-extraction based active noise control

NASA Technical Reports Server (NTRS)

Kelkar, Atul (Inventor); Joshi, Suresh M. (Inventor)

2009-01-01

A method to provide active noise control to reduce noise and vibration in reverberant acoustic enclosures such as aircraft, vehicles, appliances, instruments, industrial equipment and the like is presented. A continuous-time multi-input multi-output (MIMO) state space mathematical model of the plant is obtained via analytical modeling and system identification. Compensation is designed to render the mathematical model passive in the sense of mathematical system theory. The compensated system is checked to ensure robustness of the passive property of the plant. The check ensures that the passivity is preserved if the mathematical model parameters are perturbed from nominal values. A passivity-based controller is designed and verified using numerical simulations and then tested. The controller is designed so that the resulting closed-loop response shows the desired noise reduction.

Model Selection Methods for Mixture Dichotomous IRT Models

ERIC Educational Resources Information Center

Li, Feiming; Cohen, Allan S.; Kim, Seock-Ho; Cho, Sun-Joo

2009-01-01

This study examines model selection indices for use with dichotomous mixture item response theory (IRT) models. Five indices are considered: Akaike's information coefficient (AIC), Bayesian information coefficient (BIC), deviance information coefficient (DIC), pseudo-Bayes factor (PsBF), and posterior predictive model checks (PPMC). The five…

Regression assumptions in clinical psychology research practice-a systematic review of common misconceptions.

PubMed

Ernst, Anja F; Albers, Casper J

2017-01-01

Misconceptions about the assumptions behind the standard linear regression model are widespread and dangerous. These lead to using linear regression when inappropriate, and to employing alternative procedures with less statistical power when unnecessary. Our systematic literature review investigated employment and reporting of assumption checks in twelve clinical psychology journals. Findings indicate that normality of the variables themselves, rather than of the errors, was wrongfully held for a necessary assumption in 4% of papers that use regression. Furthermore, 92% of all papers using linear regression were unclear about their assumption checks, violating APA-recommendations. This paper appeals for a heightened awareness for and increased transparency in the reporting of statistical assumption checking.

Regression assumptions in clinical psychology research practice—a systematic review of common misconceptions

PubMed Central

Ernst, Anja F.

2017-01-01

Misconceptions about the assumptions behind the standard linear regression model are widespread and dangerous. These lead to using linear regression when inappropriate, and to employing alternative procedures with less statistical power when unnecessary. Our systematic literature review investigated employment and reporting of assumption checks in twelve clinical psychology journals. Findings indicate that normality of the variables themselves, rather than of the errors, was wrongfully held for a necessary assumption in 4% of papers that use regression. Furthermore, 92% of all papers using linear regression were unclear about their assumption checks, violating APA-recommendations. This paper appeals for a heightened awareness for and increased transparency in the reporting of statistical assumption checking. PMID:28533971

An effective automatic procedure for testing parameter identifiability of HIV/AIDS models.

PubMed

Saccomani, Maria Pia

2011-08-01

Realistic HIV models tend to be rather complex and many recent models proposed in the literature could not yet be analyzed by traditional identifiability testing techniques. In this paper, we check a priori global identifiability of some of these nonlinear HIV models taken from the recent literature, by using a differential algebra algorithm based on previous work of the author. The algorithm is implemented in a software tool, called DAISY (Differential Algebra for Identifiability of SYstems), which has been recently released (DAISY is freely available on the web site http://www.dei.unipd.it/~pia/ ). The software can be used to automatically check global identifiability of (linear and) nonlinear models described by polynomial or rational differential equations, thus providing a general and reliable tool to test global identifiability of several HIV models proposed in the literature. It can be used by researchers with a minimum of mathematical background.

75 FR 36298 - Airworthiness Directives; McDonnell Douglas Corporation Model DC-8-31, DC-8-32, DC-8-33, DC-8-41...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-06-25

... Airworthiness Limitations inspections (ALIs). This proposed AD results from a design review of the fuel tank...,'' and also adds ALI 30-1 for a pneumatic system decay check to minimize the risk of hot air impingement... 5, 2010, adds ALI 28-1, ``DC-8 Alternate and Center Auxiliary Tank Fuel Pump Control Systems Check...

Development of a Model of Soldier Effectiveness: Retranslation Materials and Results

DTIC Science & Technology

1987-05-01

covering financial responsibility, particularly the family checking account . Consequent- ly, the bad check rate for the unit drop- ped from 70 a month...Alcohol, and Aggressive Acts " Showing prudence in financial management and responsibility in personal/family matters; avoiding alcohol and other drugs or...threatening others, etc. versus " Acting irresponsibly in financial or personal/family affairs such that command time is required to counsel or otherwise

Method-independent, Computationally Frugal Convergence Testing for Sensitivity Analysis Techniques

NASA Astrophysics Data System (ADS)

Mai, Juliane; Tolson, Bryan

2017-04-01

The increasing complexity and runtime of environmental models lead to the current situation that the calibration of all model parameters or the estimation of all of their uncertainty is often computationally infeasible. Hence, techniques to determine the sensitivity of model parameters are used to identify most important parameters or model processes. All subsequent model calibrations or uncertainty estimation procedures focus then only on these subsets of parameters and are hence less computational demanding. While the examination of the convergence of calibration and uncertainty methods is state-of-the-art, the convergence of the sensitivity methods is usually not checked. If any, bootstrapping of the sensitivity results is used to determine the reliability of the estimated indexes. Bootstrapping, however, might as well become computationally expensive in case of large model outputs and a high number of bootstraps. We, therefore, present a Model Variable Augmentation (MVA) approach to check the convergence of sensitivity indexes without performing any additional model run. This technique is method- and model-independent. It can be applied either during the sensitivity analysis (SA) or afterwards. The latter case enables the checking of already processed sensitivity indexes. To demonstrate the method independency of the convergence testing method, we applied it to three widely used, global SA methods: the screening method known as Morris method or Elementary Effects (Morris 1991, Campolongo et al., 2000), the variance-based Sobol' method (Solbol' 1993, Saltelli et al. 2010) and a derivative-based method known as Parameter Importance index (Goehler et al. 2013). The new convergence testing method is first scrutinized using 12 analytical benchmark functions (Cuntz & Mai et al. 2015) where the true indexes of aforementioned three methods are known. This proof of principle shows that the method reliably determines the uncertainty of the SA results when different budgets are used for the SA. Subsequently, we focus on the model-independency by testing the frugal method using the hydrologic model mHM (www.ufz.de/mhm) with about 50 model parameters. The results show that the new frugal method is able to test the convergence and therefore the reliability of SA results in an efficient way. The appealing feature of this new technique is the necessity of no further model evaluation and therefore enables checking of already processed (and published) sensitivity results. This is one step towards reliable and transferable, published sensitivity results.

Sub-pixel analysis to support graphic security after scanning at low resolution

NASA Astrophysics Data System (ADS)

Haas, Bertrand; Cordery, Robert; Gou, Hongmei; Decker, Steve

2006-02-01

Whether in the domain of audio, video or finance, our world tends to become increasingly digital. However, for diverse reasons, the transition from analog to digital is often much extended in time, and proceeds by long steps (and sometimes never completes). One such step is the conversion of information on analog media to digital information. We focus in this paper on the conversion (scanning) of printed documents to digital images. Analog media have the advantage over digital channels that they can harbor much imperceptible information that can be used for fraud detection and forensic purposes. But this secondary information usually fails to be retrieved during the conversion step. This is particularly relevant since the Check-21 act (Check Clearing for the 21st Century act) became effective in 2004 and allows images of checks to be handled by banks as usual paper checks. We use here this situation of check scanning as our primary benchmark for graphic security features after scanning. We will first present a quick review of the most common graphic security features currently found on checks, with their specific purpose, qualities and disadvantages, and we demonstrate their poor survivability after scanning in the average scanning conditions expected from the Check-21 Act. We will then present a novel method of measurement of distances between and rotations of line elements in a scanned image: Based on an appropriate print model, we refine direct measurements to an accuracy beyond the size of a scanning pixel, so we can then determine expected distances, periodicity, sharpness and print quality of known characters, symbols and other graphic elements in a document image. Finally we will apply our method to fraud detection of documents after gray-scale scanning at 300dpi resolution. We show in particular that alterations on legitimate checks or copies of checks can be successfully detected by measuring with sub-pixel accuracy the irregularities inherently introduced by the illegitimate process.

Software Safety Analysis of a Flight Guidance System

NASA Technical Reports Server (NTRS)

Butler, Ricky W. (Technical Monitor); Tribble, Alan C.; Miller, Steven P.; Lempia, David L.

2004-01-01

This document summarizes the safety analysis performed on a Flight Guidance System (FGS) requirements model. In particular, the safety properties desired of the FGS model are identified and the presence of the safety properties in the model is formally verified. Chapter 1 provides an introduction to the entire project, while Chapter 2 gives a brief overview of the problem domain, the nature of accidents, model based development, and the four-variable model. Chapter 3 outlines the approach. Chapter 4 presents the results of the traditional safety analysis techniques and illustrates how the hazardous conditions associated with the system trace into specific safety properties. Chapter 5 presents the results of the formal methods analysis technique model checking that was used to verify the presence of the safety properties in the requirements model. Finally, Chapter 6 summarizes the main conclusions of the study, first and foremost that model checking is a very effective verification technique to use on discrete models with reasonable state spaces. Additional supporting details are provided in the appendices.

Space shuttle prototype check valve development

NASA Technical Reports Server (NTRS)

Tellier, G. F.

1976-01-01

Contaminant-resistant seal designs and a dynamically stable prototype check valve for the orbital maneuvering and reaction control helium pressurization systems of the space shuttle were developed. Polymer and carbide seal models were designed and tested. Perfluoroelastomers compatible with N2O4 and N2H4 types were evaluated and compared with Teflon in flat and captive seal models. Low load sealing and contamination resistance tests demonstrated cutter seal superiority over polymer seals. Ceramic and carbide materials were evaluated for N2O4 service using exposure to RFNA as a worst case screen; chemically vapor deposited tungsten carbide was shown to be impervious to the acid after 6 months immersion. A unique carbide shell poppet/cutter seat check valve was designed and tested to demonstrate low cracking pressure ( 2.0 psid), dynamic stability under all test bench flow conditions, contamination resistance (0.001 inch CRES wires cut with 1.5 pound seat load) and long life of 100,000 cycles (leakage 1.0 scc/hr helium from 0.1 to 400 psig).

Birth/death process model

NASA Technical Reports Server (NTRS)

Solloway, C. B.; Wakeland, W.

1976-01-01

First-order Markov model developed on digital computer for population with specific characteristics. System is user interactive, self-documenting, and does not require user to have complete understanding of underlying model details. Contains thorough error-checking algorithms on input and default capabilities.

Symbolic discrete event system specification

NASA Technical Reports Server (NTRS)

Zeigler, Bernard P.; Chi, Sungdo

1992-01-01

Extending discrete event modeling formalisms to facilitate greater symbol manipulation capabilities is important to further their use in intelligent control and design of high autonomy systems. An extension to the DEVS formalism that facilitates symbolic expression of event times by extending the time base from the real numbers to the field of linear polynomials over the reals is defined. A simulation algorithm is developed to generate the branching trajectories resulting from the underlying nondeterminism. To efficiently manage symbolic constraints, a consistency checking algorithm for linear polynomial constraints based on feasibility checking algorithms borrowed from linear programming has been developed. The extended formalism offers a convenient means to conduct multiple, simultaneous explorations of model behaviors. Examples of application are given with concentration on fault model analysis.

SU-F-T-300: Impact of Electron Density Modeling of ArcCHECK Cylindricaldiode Array On 3DVH Patient Specific QA Software Tool Analysis

DOE Office of Scientific and Technical Information (OSTI.GOV)

Patwe, P; Mhatre, V; Dandekar, P

Purpose: 3DVH software is a patient specific quality assurance tool which estimates the 3D dose to the patient specific geometry with the help of Planned Dose Perturbation algorithm. The purpose of this study is to evaluate the impact of HU value of ArcCHECK phantom entered in Eclipse TPS on 3D dose & DVH QA analysis. Methods: Manufacturer of ArcCHECK phantom provides CT data set of phantom & recommends considering it as a homogeneous phantom with electron density (1.19 gm/cc or 282 HU) close to PMMA. We performed this study on Eclipse TPS (V13, VMS) & trueBEAM STx VMS Linac &more » ArcCHECK phantom (SNC). Plans were generated for 6MV photon beam, 20cm×20cm field size at isocentre & SPD (Source to phantom distance) of 86.7 cm to deliver 100cGy at isocentre. 3DVH software requires patients DICOM data generated by TPS & plan delivered on ArcCHECK phantom. Plans were generated in TPS by assigning different HU values to phantom. We analyzed gamma index & the dose profile for all plans along vertical down direction of beam’s central axis for Entry, Exit & Isocentre dose. Results: The global gamma passing rate (2% & 2mm) for manufacturer recommended HU value 282 was 96.3%. Detector entry, Isocentre & detector exit Doses were 1.9048 (1.9270), 1.00(1.0199) & 0.5078(0.527) Gy for TPS (Measured) respectively.The global gamma passing rate for electron density 1.1302 gm/cc was 98.6%. Detector entry, Isocentre & detector exit Doses were 1.8714 (1.8873), 1.00(0.9988) & 0.5211(0.516) Gy for TPS (Measured) respectively. Conclusion: Electron density value assigned by manufacturer does not hold true for every user. Proper modeling of electron density of ArcCHECK in TPS is essential to avoid systematic error in dose calculation of patient specific QA.« less

Martina Franca donkey meat quality: Influence of slaughter age and suckling technique.

PubMed

De Palo, P; Tateo, A; Maggiolino, A; Marino, R; Ceci, E; Nisi, A; Lorenzo, J M

2017-12-01

This work aimed to evaluate the effect of suckling technique and slaughter age on Martina Franca donkey meat quality. Twenty Martina Franca male foals were involved in the trial. Foals naturally assumed colostrum within 4h from birth. Afterwards, 10 foals were partially artificially suckled (AS), and 10 foals were naturally suckled (NS). All the foals were weaned at 180d, then housed indoors and fed the same diet. Ten donkeys were slaughtered at 12months and the other 10 at the age of 18months. Samples of Longissimus thoracis et lumborum (LTL) were taken from each foal for chemical analysis, then rheological parameters, oxidative profile, colorimetric parameters and fatty acid profile were assessed. Older donkeys (18months) fed with natural milk presented the highest intramuscular fat (IMF) and meat protein content. From a dietary view point, IMF acid composition showed a more favourable profile in meat from artificially-reared donkeys compared to naturally-suckled ones. Copyright © 2017 Elsevier Ltd. All rights reserved.

The effect of temperature during retail display on the colour stability of CO pretreated vacuum packaged beef steaks.

PubMed

Van Rooyen, Lauren Anne; Allen, Paul; Gallagher, Eimear I; O'Connor, David I

2018-05-24

The effect of CO pretreatments applied to beef striploin steaks (Longissimus thoracis et lumborum, LTL) prior to vacuum packaging and display temperature on colour stability, shelf life and tenderness was determined. Steaks were exposed to 5% CO, 60% CO 2 and 35% N 2 for 3 (CO3), 5 (CO5) or 7 (CO7) h, followed by 28 days display at 2 °C (good industry practice) or 6 °C (mild abuse). CO5 was the optimum exposure time as it induced the desirable colour while not retaining the bright colour, irrespective of display temperature. K/S ratios confirmed that CO pretreatment did not mask spoilage and could be more sensitive than colour parameters at monitoring discoloration as colour was not retained. Exposure to CO did not have any negative effect on meat quality attributes, while mild temperature abuse (6 °C) increased purge loss and decreased pH. Copyright © 2018 Elsevier Ltd. All rights reserved.

Assembly of a check-patterned CuSx-TiO2 film with an electron-rich pool and its application for the photoreduction of carbon dioxide to methane

NASA Astrophysics Data System (ADS)

Lee, Homin; Kwak, Byeong Sub; Park, No-Kuk; Baek, Jeom-In; Ryu, Ho-Jung; Kang, Misook

2017-01-01

A new check-patterned CuSx-TiO2 film was designed to improve the photoreduction of CO2 to CH4. The check-patterned CuSx-TiO2 film with a 3D-network microstructure was fabricated by a facile squeeze method. The as-synthesized TiO2 and CuSx powders, as well as the patterned film, were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), UV-visible spectroscopy, cyclic voltammetry (CV), and photoluminescence (PL) spectroscopy, as well as photocurrent density and CO2 temperature-programmed desorption (TPD) measurements. Compared to pure CuSx and TiO2, the check-patterned CuSx-TiO2 film exhibited significantly increased adsorption of CO2 on its networked microstructure, attributed to the enlarged interfaces between the microparticles. The check-patterned CuSx-TiO2 film exhibited superior photocatalytic behavior, with 53.2 μmolgcat-1 L-1 of CH4 produced after 8 h of reaction, whereas 18.1 and 7.3 μmolgcat-1 L-1 of CH4 were produced from pure TiO2 and CuSx films under the same reaction conditions, respectively. A model for enhanced photoactivity over the check-patterned CuSx - TiO2 film was proposed. Results indicated that the check-patterned CuS-TiO2 material is quite promising as a photocatalyst for the reduction of CO2 to CH4.

Formal Validation of Fault Management Design Solutions

NASA Technical Reports Server (NTRS)

Gibson, Corrina; Karban, Robert; Andolfato, Luigi; Day, John

2013-01-01

The work presented in this paper describes an approach used to develop SysML modeling patterns to express the behavior of fault protection, test the model's logic by performing fault injection simulations, and verify the fault protection system's logical design via model checking. A representative example, using a subset of the fault protection design for the Soil Moisture Active-Passive (SMAP) system, was modeled with SysML State Machines and JavaScript as Action Language. The SysML model captures interactions between relevant system components and system behavior abstractions (mode managers, error monitors, fault protection engine, and devices/switches). Development of a method to implement verifiable and lightweight executable fault protection models enables future missions to have access to larger fault test domains and verifiable design patterns. A tool-chain to transform the SysML model to jpf-Statechart compliant Java code and then verify the generated code via model checking was established. Conclusions and lessons learned from this work are also described, as well as potential avenues for further research and development.

Using chemical organization theory for model checking

PubMed Central

Kaleta, Christoph; Richter, Stephan; Dittrich, Peter

2009-01-01

Motivation: The increasing number and complexity of biomodels makes automatic procedures for checking the models' properties and quality necessary. Approaches like elementary mode analysis, flux balance analysis, deficiency analysis and chemical organization theory (OT) require only the stoichiometric structure of the reaction network for derivation of valuable information. In formalisms like Systems Biology Markup Language (SBML), however, information about the stoichiometric coefficients required for an analysis of chemical organizations can be hidden in kinetic laws. Results: First, we introduce an algorithm that uncovers stoichiometric information that might be hidden in the kinetic laws of a reaction network. This allows us to apply OT to SBML models using modifiers. Second, using the new algorithm, we performed a large-scale analysis of the 185 models contained in the manually curated BioModels Database. We found that for 41 models (22%) the set of organizations changes when modifiers are considered correctly. We discuss one of these models in detail (BIOMD149, a combined model of the ERK- and Wnt-signaling pathways), whose set of organizations drastically changes when modifiers are considered. Third, we found inconsistencies in 5 models (3%) and identified their characteristics. Compared with flux-based methods, OT is able to identify those species and reactions more accurately [in 26 cases (14%)] that can be present in a long-term simulation of the model. We conclude that our approach is a valuable tool that helps to improve the consistency of biomodels and their repositories. Availability: All data and a JAVA applet to check SBML-models is available from http://www.minet.uni-jena.de/csb/prj/ot/tools Contact: dittrich@minet.uni-jena.de Supplementary information: Supplementary data are available at Bioinformatics online. PMID:19468053

Software Model Checking Without Source Code

NASA Technical Reports Server (NTRS)

Chaki, Sagar; Ivers, James

2009-01-01

We present a framework, called AIR, for verifying safety properties of assembly language programs via software model checking. AIR extends the applicability of predicate abstraction and counterexample guided abstraction refinement to the automated verification of low-level software. By working at the assembly level, AIR allows verification of programs for which source code is unavailable-such as legacy and COTS software-and programs that use features-such as pointers, structures, and object-orientation-that are problematic for source-level software verification tools. In addition, AIR makes no assumptions about the underlying compiler technology. We have implemented a prototype of AIR and present encouraging results on several non-trivial examples.

Location Contexts of User Check-Ins to Model Urban Geo Life-Style Patterns

PubMed Central

Hasan, Samiul; Ukkusuri, Satish V.

2015-01-01

Geo-location data from social media offers us information, in new ways, to understand people's attitudes and interests through their activity choices. In this paper, we explore the idea of inferring individual life-style patterns from activity-location choices revealed in social media. We present a model to understand life-style patterns using the contextual information (e. g. location categories) of user check-ins. Probabilistic topic models are developed to infer individual geo life-style patterns from two perspectives: i) to characterize the patterns of user interests to different types of places and ii) to characterize the patterns of user visits to different neighborhoods. The method is applied to a dataset of Foursquare check-ins of the users from New York City. The co-existence of several location contexts and the corresponding probabilities in a given pattern provide useful information about user interests and choices. It is found that geo life-style patterns have similar items—either nearby neighborhoods or similar location categories. The semantic and geographic proximity of the items in a pattern reflects the hidden regularity in user preferences and location choice behavior. PMID:25970430

Dynamic modeling and simulation of an integral bipropellant propulsion double-valve combined test system

NASA Astrophysics Data System (ADS)

Chen, Yang; Wang, Huasheng; Xia, Jixia; Cai, Guobiao; Zhang, Zhenpeng

2017-04-01

For the pressure reducing regulator and check valve double-valve combined test system in an integral bipropellant propulsion system, a system model is established with modular models of various typical components. The simulation research is conducted on the whole working process of an experiment of 9 MPa working condition from startup to rated working condition and finally to shutdown. Comparison of simulation results with test data shows: five working conditions including standby, startup, rated pressurization, shutdown and halt and nine stages of the combined test system are comprehensively disclosed; valve-spool opening and closing details of the regulator and two check valves are accurately revealed; the simulation also clarifies two phenomena which test data are unable to clarify, one is the critical opening state in which the check valve spools slightly open and close alternately in their own fully closed positions, the other is the obvious effects of flow-field temperature drop and temperature rise in pipeline network with helium gas flowing. Moreover, simulation results with consideration of component wall heat transfer are closer to the test data than those under the adiabatic-wall condition, and more able to reveal the dynamic characteristics of the system in various working stages.

Teaching "Instant Experience" with Graphical Model Validation Techniques

ERIC Educational Resources Information Center

Ekstrøm, Claus Thorn

2014-01-01

Graphical model validation techniques for linear normal models are often used to check the assumptions underlying a statistical model. We describe an approach to provide "instant experience" in looking at a graphical model validation plot, so it becomes easier to validate if any of the underlying assumptions are violated.

Bayesian truncation errors in chiral effective field theory: model checking and accounting for correlations

NASA Astrophysics Data System (ADS)

Melendez, Jordan; Wesolowski, Sarah; Furnstahl, Dick

2017-09-01

Chiral effective field theory (EFT) predictions are necessarily truncated at some order in the EFT expansion, which induces an error that must be quantified for robust statistical comparisons to experiment. A Bayesian model yields posterior probability distribution functions for these errors based on expectations of naturalness encoded in Bayesian priors and the observed order-by-order convergence pattern of the EFT. As a general example of a statistical approach to truncation errors, the model was applied to chiral EFT for neutron-proton scattering using various semi-local potentials of Epelbaum, Krebs, and Meißner (EKM). Here we discuss how our model can learn correlation information from the data and how to perform Bayesian model checking to validate that the EFT is working as advertised. Supported in part by NSF PHY-1614460 and DOE NUCLEI SciDAC DE-SC0008533.

Automated Environment Generation for Software Model Checking

NASA Technical Reports Server (NTRS)

Tkachuk, Oksana; Dwyer, Matthew B.; Pasareanu, Corina S.

2003-01-01

A key problem in model checking open systems is environment modeling (i.e., representing the behavior of the execution context of the system under analysis). Software systems are fundamentally open since their behavior is dependent on patterns of invocation of system components and values defined outside the system but referenced within the system. Whether reasoning about the behavior of whole programs or about program components, an abstract model of the environment can be essential in enabling sufficiently precise yet tractable verification. In this paper, we describe an approach to generating environments of Java program fragments. This approach integrates formally specified assumptions about environment behavior with sound abstractions of environment implementations to form a model of the environment. The approach is implemented in the Bandera Environment Generator (BEG) which we describe along with our experience using BEG to reason about properties of several non-trivial concurrent Java programs.

Modelling of influential parameters on a continuous evaporation process by Doehlert shells

PubMed Central

Porte, Catherine; Havet, Jean-Louis; Daguet, David

2003-01-01

The modelling of the parameters that influence the continuous evaporation of an alcoholic extract was considered using Doehlert matrices. The work was performed with a wiped falling film evaporator that allowed us to study the influence of the pressure, temperature, feed flow and dry matter of the feed solution on the dry matter contents of the resulting concentrate, and the productivity of the process. The Doehlert shells were used to model the influential parameters. The pattern obtained from the experimental results was checked allowing for some dysfunction in the unit. The evaporator was modified and a new model applied; the experimental results were then in agreement with the equations. The model was finally determined and successfully checked in order to obtain an 8% dry matter concentrate with the best productivity; the results fit in with the industrial constraints of subsequent processes. PMID:18924887

Re-engineering pre-employment check-up systems: a model for improving health services.

PubMed

Rateb, Said Abdel Hakim; El Nouman, Azza Abdel Razek; Rateb, Moshira Abdel Hakim; Asar, Mohamed Naguib; El Amin, Ayman Mohammed; Gad, Saad abdel Aziz; Mohamed, Mohamed Salah Eldin

2011-01-01

The purpose of this paper is to develop a model for improving health services provided by the pre-employment medical fitness check-up system affiliated to Egypt's Health Insurance Organization (HIO). Operations research, notably system re-engineering, is used in six randomly selected centers and findings before and after re-engineering are compared. The re-engineering model follows a systems approach, focusing on three areas: structure, process and outcome. The model is based on six main components: electronic booking, standardized check-up processes, protected medical documents, advanced archiving through an electronic content management (ECM) system, infrastructure development, and capacity building. The model originates mainly from customer needs and expectations. The centers' monthly customer flow increased significantly after re-engineering. The mean time spent per customer cycle improved after re-engineering--18.3 +/- 5.5 minutes as compared to 48.8 +/- 14.5 minutes before. Appointment delay was also significantly decreased from an average 18 to 6.2 days. Both beneficiaries and service providers were significantly more satisfied with the services after re-engineering. The model proves that re-engineering program costs are exceeded by increased revenue. Re-engineering in this study involved multiple structure and process elements. The literature review did not reveal similar re-engineering healthcare packages. Therefore, each element was compared separately. This model is highly recommended for improving service effectiveness and efficiency. This research is the first in Egypt to apply the re-engineering approach to public health systems. Developing user-friendly models for service improvement is an added value.

Development of a check sheet for collecting information necessary for occupational safety and health activities and building relevant systems in overseas business places.

PubMed

Kajiki, Shigeyuki; Kobayashi, Yuichi; Uehara, Masamichi; Nakanishi, Shigemoto; Mori, Koji

2016-06-07

This study aimed to develop an information gathering check sheet to efficiently collect information necessary for Japanese companies to build global occupational safety and health management systems in overseas business places. The study group consisted of 2 researchers with occupational physician careers in a foreign-affiliated company in Japan and 3 supervising occupational physicians who were engaged in occupational safety and health activities in overseas business places. After investigating information and sources of information necessary for implementing occupational safety and health activities and building relevant systems, we conducted information acquisition using an information gathering check sheet in the field, by visiting 10 regions in 5 countries (first phase). The accuracy of the information acquired and the appropriateness of the information sources were then verified in study group meetings to improve the information gathering check sheet. Next, the improved information gathering check sheet was used in another setting (3 regions in 1 country) to confirm its efficacy (second phase), and the information gathering check sheet was thereby completed. The information gathering check sheet was composed of 9 major items (basic information on the local business place, safety and health overview, safety and health systems, safety and health staff, planning/implementation/evaluation/improvement, safety and health activities, laws and administrative organs, local medical care systems and public health, and medical support for resident personnel) and 61 medium items. We relied on the following eight information sources: the internet, company (local business place and head office in Japan), embassy/consulate, ISO certification body, university or other educational institutions, and medical institutions (aimed at Japanese people or at local workers). Through multiple study group meetings and a two-phased field survey (13 regions in 6 countries), an information gathering check sheet was completed. We confirmed the possibility that this check sheet would enable the user to obtain necessary information when expanding safety and health activities in a country or region that is new to the user. It is necessary in the future to evaluate safety and health systems and activities using this information gathering check sheet in a local business place in any country in which a Japanese business will be established, and to verify the efficacy of the check sheet by conducting model programs to test specific approaches.

Directed Bak-Sneppen Model for Food Chains

NASA Astrophysics Data System (ADS)

Stauffer, D.; Jan, N.

A modification of the Bak-Sneppen model to include simple elements of Darwinian evolution is used to check the survival of prey and predators in long food chains. Mutations, selection, and starvation resulting from depleted prey are incorporated in this model.

Detecting Inconsistencies in Multi-View Models with Variability

NASA Astrophysics Data System (ADS)

Lopez-Herrejon, Roberto Erick; Egyed, Alexander

Multi-View Modeling (MVM) is a common modeling practice that advocates the use of multiple, different and yet related models to represent the needs of diverse stakeholders. Of crucial importance in MVM is consistency checking - the description and verification of semantic relationships amongst the views. Variability is the capacity of software artifacts to vary, and its effective management is a core tenet of the research in Software Product Lines (SPL). MVM has proven useful for developing one-of-a-kind systems; however, to reap the potential benefits of MVM in SPL it is vital to provide consistency checking mechanisms that cope with variability. In this paper we describe how to address this need by applying Safe Composition - the guarantee that all programs of a product line are type safe. We evaluate our approach with a case study.

Approximate Model Checking of PCTL Involving Unbounded Path Properties

NASA Astrophysics Data System (ADS)

Basu, Samik; Ghosh, Arka P.; He, Ru

We study the problem of applying statistical methods for approximate model checking of probabilistic systems against properties encoded as PCTL formulas. Such approximate methods have been proposed primarily to deal with state-space explosion that makes the exact model checking by numerical methods practically infeasible for large systems. However, the existing statistical methods either consider a restricted subset of PCTL, specifically, the subset that can only express bounded until properties; or rely on user-specified finite bound on the sample path length. We propose a new method that does not have such restrictions and can be effectively used to reason about unbounded until properties. We approximate probabilistic characteristics of an unbounded until property by that of a bounded until property for a suitably chosen value of the bound. In essence, our method is a two-phase process: (a) the first phase is concerned with identifying the bound k 0; (b) the second phase computes the probability of satisfying the k 0-bounded until property as an estimate for the probability of satisfying the corresponding unbounded until property. In both phases, it is sufficient to verify bounded until properties which can be effectively done using existing statistical techniques. We prove the correctness of our technique and present its prototype implementations. We empirically show the practical applicability of our method by considering different case studies including a simple infinite-state model, and large finite-state models such as IPv4 zeroconf protocol and dining philosopher protocol modeled as Discrete Time Markov chains.

Sediment depositions upstream of open check dams: new elements from small scale models

NASA Astrophysics Data System (ADS)

Piton, Guillaume; Le Guern, Jules; Carbonari, Costanza; Recking, Alain

2015-04-01

Torrent hazard mitigation remains a big issue in mountainous regions. In steep slope streams and especially in their fan part, torrential floods mainly result from abrupt and massive sediment deposits. To curtail such phenomenon, soil conservation measures as well as torrent control works have been undertaken for decades. Since the 1950s, open check dams complete other structural and non-structural measures in watershed scale mitigation plans1. They are often built to trap sediments near the fan apexes. The development of earthmoving machinery after the WWII facilitated the dredging operations of open check dams. Hundreds of these structures have thus been built for 60 years. Their design evolved with the improving comprehension of torrential hydraulics and sediment transport; however this kind of structure has a general tendency to trap most of the sediments supplied by the headwaters. Secondary effects as channel incision downstream of the traps often followed an open check dam creation. This sediment starvation trend tends to propagate to the main valley rivers and to disrupt past geomorphic equilibriums. Taking it into account and to diminish useless dredging operation, a better selectivity of sediment trapping must be sought in open check dams, i.e. optimal open check dams would trap sediments during dangerous floods and flush them during normal small floods. An accurate description of the hydraulic and deposition processes that occur in sediment traps is needed to optimize existing structures and to design best-adjusted new structures. A literature review2 showed that if design criteria exist for the structure itself, little information is available on the dynamic of the sediment depositions upstream of open check dams, i.e. what are the geomorphic patterns that occur during the deposition?, what are the relevant friction laws and sediment transport formula that better describe massive depositions in sediment traps?, what are the range of Froude and Shields numbers that the flows tend to adopt? New small scale model experiments have been undertaken focusing on depositions processes and their related hydraulics. Accurate photogrammetric measurements allowed us to better describe the deposition processes3. Large Scale Particle Image Velocimetry (LS-PIV) was performed to determine surface velocity fields in highly active channels with low grain submersion4. We will present preliminary results of our experiments showing the new elements we observed in massive deposit dynamics. REFERENCES 1.Armanini, A., Dellagiacoma, F. & Ferrari, L. From the check dam to the development of functional check dams. Fluvial Hydraulics of Mountain Regions 37, 331-344 (1991). 2.Piton, G. & Recking, A. Design of sediment traps with open check dams: a review, part I: hydraulic and deposition processes. (Accepted by the) Journal of Hydraulic Engineering 1-23 (2015). 3.Le Guern, J. Ms Thesis: Modélisation physique des plages de depot : analyse de la dynamique de remplissage.(2014) . 4.Carbonari, C. Ms Thesis: Small scale experiments of deposition processes occuring in sediment traps, LS-PIV measurments and geomorphological descriptions. (in preparation).

Experience Report: A Do-It-Yourself High-Assurance Compiler

NASA Technical Reports Server (NTRS)

Pike, Lee; Wegmann, Nis; Niller, Sebastian; Goodloe, Alwyn

2012-01-01

Embedded domain-specific languages (EDSLs) are an approach for quickly building new languages while maintaining the advantages of a rich metalanguage. We argue in this experience report that the "EDSL approach" can surprisingly ease the task of building a high-assurance compiler.We do not strive to build a fully formally-verified tool-chain, but take a "do-it-yourself" approach to increase our confidence in compiler-correctness without too much effort. Copilot is an EDSL developed by Galois, Inc. and the National Institute of Aerospace under contract to NASA for the purpose of runtime monitoring of flight-critical avionics. We report our experience in using type-checking, QuickCheck, and model-checking "off-the-shelf" to quickly increase confidence in our EDSL tool-chain.

TEAMS Model Analyzer

NASA Technical Reports Server (NTRS)

Tijidjian, Raffi P.

2010-01-01

The TEAMS model analyzer is a supporting tool developed to work with models created with TEAMS (Testability, Engineering, and Maintenance System), which was developed by QSI. In an effort to reduce the time spent in the manual process that each TEAMS modeler must perform in the preparation of reporting for model reviews, a new tool has been developed as an aid to models developed in TEAMS. The software allows for the viewing, reporting, and checking of TEAMS models that are checked into the TEAMS model database. The software allows the user to selectively model in a hierarchical tree outline view that displays the components, failure modes, and ports. The reporting features allow the user to quickly gather statistics about the model, and generate an input/output report pertaining to all of the components. Rules can be automatically validated against the model, with a report generated containing resulting inconsistencies. In addition to reducing manual effort, this software also provides an automated process framework for the Verification and Validation (V&V) effort that will follow development of these models. The aid of such an automated tool would have a significant impact on the V&V process.

Test of Hadronic Interaction Models with the KASCADE Hadron Calorimeter

NASA Astrophysics Data System (ADS)

Milke, J.; KASCADE Collaboration

The interpretation of extensive air shower (EAS) measurements often requires the comparison with EAS simulations based on high-energy hadronic interaction models. These interaction models have to extrapolate into kinematical regions and energy ranges beyond the limit of present accelerators. Therefore, it is necessary to test whether these models are able to describe the EAS development in a consistent way. By measuring simultaneously the hadronic, electromagnetic, and muonic part of an EAS the experiment KASCADE offers best facilities for checking the models. For the EAS simulations the program CORSIKA with several hadronic event generators implemented is used. Different hadronic observables, e.g. hadron number, energy spectrum, lateral distribution, are investigated, as well as their correlations with the electromagnetic and muonic shower size. By comparing measurements and simulations the consistency of the description of the EAS development is checked. First results with the new interaction model NEXUS and the version II.5 of the model DPMJET, recently included in CORSIKA, are presented and compared with QGSJET simulations.

Implementing parallel spreadsheet models for health policy decisions: The impact of unintentional errors on model projections

PubMed Central

Bailey, Stephanie L.; Bono, Rose S.; Nash, Denis; Kimmel, April D.

2018-01-01

Background Spreadsheet software is increasingly used to implement systems science models informing health policy decisions, both in academia and in practice where technical capacity may be limited. However, spreadsheet models are prone to unintentional errors that may not always be identified using standard error-checking techniques. Our objective was to illustrate, through a methodologic case study analysis, the impact of unintentional errors on model projections by implementing parallel model versions. Methods We leveraged a real-world need to revise an existing spreadsheet model designed to inform HIV policy. We developed three parallel versions of a previously validated spreadsheet-based model; versions differed by the spreadsheet cell-referencing approach (named single cells; column/row references; named matrices). For each version, we implemented three model revisions (re-entry into care; guideline-concordant treatment initiation; immediate treatment initiation). After standard error-checking, we identified unintentional errors by comparing model output across the three versions. Concordant model output across all versions was considered error-free. We calculated the impact of unintentional errors as the percentage difference in model projections between model versions with and without unintentional errors, using +/-5% difference to define a material error. Results We identified 58 original and 4,331 propagated unintentional errors across all model versions and revisions. Over 40% (24/58) of original unintentional errors occurred in the column/row reference model version; most (23/24) were due to incorrect cell references. Overall, >20% of model spreadsheet cells had material unintentional errors. When examining error impact along the HIV care continuum, the percentage difference between versions with and without unintentional errors ranged from +3% to +16% (named single cells), +26% to +76% (column/row reference), and 0% (named matrices). Conclusions Standard error-checking techniques may not identify all errors in spreadsheet-based models. Comparing parallel model versions can aid in identifying unintentional errors and promoting reliable model projections, particularly when resources are limited. PMID:29570737

Implementing parallel spreadsheet models for health policy decisions: The impact of unintentional errors on model projections.

PubMed

Bailey, Stephanie L; Bono, Rose S; Nash, Denis; Kimmel, April D

2018-01-01

Spreadsheet software is increasingly used to implement systems science models informing health policy decisions, both in academia and in practice where technical capacity may be limited. However, spreadsheet models are prone to unintentional errors that may not always be identified using standard error-checking techniques. Our objective was to illustrate, through a methodologic case study analysis, the impact of unintentional errors on model projections by implementing parallel model versions. We leveraged a real-world need to revise an existing spreadsheet model designed to inform HIV policy. We developed three parallel versions of a previously validated spreadsheet-based model; versions differed by the spreadsheet cell-referencing approach (named single cells; column/row references; named matrices). For each version, we implemented three model revisions (re-entry into care; guideline-concordant treatment initiation; immediate treatment initiation). After standard error-checking, we identified unintentional errors by comparing model output across the three versions. Concordant model output across all versions was considered error-free. We calculated the impact of unintentional errors as the percentage difference in model projections between model versions with and without unintentional errors, using +/-5% difference to define a material error. We identified 58 original and 4,331 propagated unintentional errors across all model versions and revisions. Over 40% (24/58) of original unintentional errors occurred in the column/row reference model version; most (23/24) were due to incorrect cell references. Overall, >20% of model spreadsheet cells had material unintentional errors. When examining error impact along the HIV care continuum, the percentage difference between versions with and without unintentional errors ranged from +3% to +16% (named single cells), +26% to +76% (column/row reference), and 0% (named matrices). Standard error-checking techniques may not identify all errors in spreadsheet-based models. Comparing parallel model versions can aid in identifying unintentional errors and promoting reliable model projections, particularly when resources are limited.

Quality assurance of weather data for agricultural system model input

USDA-ARS?s Scientific Manuscript database

It is well known that crop production and hydrologic variation on watersheds is weather related. Rarely, however, is meteorological data quality checks reported for agricultural systems model research. We present quality assurance procedures for agricultural system model weather data input. Problems...

Rat Models and Identification of Candidate Early Serum Biomarkers of Battlefield Traumatic Brain Injury

DTIC Science & Technology

2007-07-31

brain injury) All surgeries were performed using aseptic technique. Animals were checked for pain /distress immediately prior to anesthesia/surgery... Pain /distress checks were performed at 3, 6, 12, 24, 36, 48, 60, and 72 hours post-injury. Fluid Percussion Injury (FPI) For animals in the...NIH), and Neurobehavioral Scale (NBS). The criteria used to obtain the scores are detailed in Tables 2 and 3. As an additional endpoint, we also

Employing the Intelligence Cycle Process Model Within the Homeland Security Enterprise

DTIC Science & Technology

2013-12-01

the Iraq anti-war movement, a former U.S. Congresswoman, the U.S. Treasury Department and hip hop bands to spread Sharia law in the U.S. A Virginia...challenges remain with threat notification, access to information, and database management of information that may have contributed the 2013 Boston...The FBI said it took a number of investigative steps to check on the request, including looking at his travel history, checking databases for

Modeling and analysis of cell membrane systems with probabilistic model checking

PubMed Central

2011-01-01

Background Recently there has been a growing interest in the application of Probabilistic Model Checking (PMC) for the formal specification of biological systems. PMC is able to exhaustively explore all states of a stochastic model and can provide valuable insight into its behavior which are more difficult to see using only traditional methods for system analysis such as deterministic and stochastic simulation. In this work we propose a stochastic modeling for the description and analysis of sodium-potassium exchange pump. The sodium-potassium pump is a membrane transport system presents in all animal cell and capable of moving sodium and potassium ions against their concentration gradient. Results We present a quantitative formal specification of the pump mechanism in the PRISM language, taking into consideration a discrete chemistry approach and the Law of Mass Action aspects. We also present an analysis of the system using quantitative properties in order to verify the pump reversibility and understand the pump behavior using trend labels for the transition rates of the pump reactions. Conclusions Probabilistic model checking can be used along with other well established approaches such as simulation and differential equations to better understand pump behavior. Using PMC we can determine if specific events happen such as the potassium outside the cell ends in all model traces. We can also have a more detailed perspective on its behavior such as determining its reversibility and why its normal operation becomes slow over time. This knowledge can be used to direct experimental research and make it more efficient, leading to faster and more accurate scientific discoveries. PMID:22369714

Software Model Checking of ARINC-653 Flight Code with MCP

NASA Technical Reports Server (NTRS)

Thompson, Sarah J.; Brat, Guillaume; Venet, Arnaud

2010-01-01

The ARINC-653 standard defines a common interface for Integrated Modular Avionics (IMA) code. In particular, ARINC-653 Part 1 specifies a process- and partition-management API that is analogous to POSIX threads, but with certain extensions and restrictions intended to support the implementation of high reliability flight code. MCP is a software model checker, developed at NASA Ames, that provides capabilities for model checking C and C++ source code. In this paper, we present recent work aimed at implementing extensions to MCP that support ARINC-653, and we discuss the challenges and opportunities that consequentially arise. Providing support for ARINC-653 s time and space partitioning is nontrivial, though there are implicit benefits for partial order reduction possible as a consequence of the API s strict interprocess communication policy.

Swarm Verification

NASA Technical Reports Server (NTRS)

Holzmann, Gerard J.; Joshi, Rajeev; Groce, Alex

2008-01-01

Reportedly, supercomputer designer Seymour Cray once said that he would sooner use two strong oxen to plow a field than a thousand chickens. Although this is undoubtedly wise when it comes to plowing a field, it is not so clear for other types of tasks. Model checking problems are of the proverbial "search the needle in a haystack" type. Such problems can often be parallelized easily. Alas, none of the usual divide and conquer methods can be used to parallelize the working of a model checker. Given that it has become easier than ever to gain access to large numbers of computers to perform even routine tasks it is becoming more and more attractive to find alternate ways to use these resources to speed up model checking tasks. This paper describes one such method, called swarm verification.

75 FR 53857 - Airworthiness Directives; Eurocopter France Model SA330J Helicopters

Federal Register 2010, 2011, 2012, 2013, 2014

2010-09-02

... Airworthiness Directives; Eurocopter France Model SA330J Helicopters AGENCY: Federal Aviation Administration... known U.S. owners and operators of Eurocopter France (Eurocopter) Model SA330J helicopters by individual...'' rather than checking for ``play.'' This helicopter model is manufactured in France and is type...

State background checks for gun purchase and firearm deaths: an exploratory study.

PubMed

Sen, Bisakha; Panjamapirom, Anantachai

2012-10-01

This study examines the relationship between the types of background-information check required by states prior to firearm purchases, and firearm homicide and suicide deaths. Negative binomial models are used to analyze state-level data for homicides and suicides in the U.S. from 1996 to 2005. Data on types of background information are retrieved from the Surveys of State Procedures Related to Firearm Sales, and the violent death data are from the WISQARS. Several other state level factors were controlled for. More background checks are associated with fewer homicide (IRR:0.93, 95% CI:0.91-0.96) and suicide (IRR:0.98, 95% CI:0.96-1.00) deaths. Firearm homicide deaths are lower when states have checks for restraining orders (IRR:0.87, 95% CI:0.79-0.95) and fugitive status (IRR:0.79, 95% CI:0.72-0.88). Firearm suicide deaths are lower when states have background checks for mental illness (IRR:0.96, 95% CI:0.92-0.99), fugitive status (IRR:0.95, 95% CI:0.90-0.99) and misdemeanors (IRR:0.95, 95% CI:0.92-1.00). It does not appear that reductions in firearm deaths are offset by increases in non-firearm violent deaths. More extensive background checks prior to gun purchase are mostly associated with reductions in firearm homicide and suicide deaths. Several study limitations are acknowledged, and further research is called for to ascertain causality. Copyright © 2012 Elsevier Inc. All rights reserved.

Towards a Semantically-Enabled Control Strategy for Building Simulations: Integration of Semantic Technologies and Model Predictive Control

DOE Office of Scientific and Technical Information (OSTI.GOV)

Delgoshaei, Parastoo; Austin, Mark A.; Pertzborn, Amanda J.

State-of-the-art building simulation control methods incorporate physical constraints into their mathematical models, but omit implicit constraints associated with policies of operation and dependency relationships among rules representing those constraints. To overcome these shortcomings, there is a recent trend in enabling the control strategies with inference-based rule checking capabilities. One solution is to exploit semantic web technologies in building simulation control. Such approaches provide the tools for semantic modeling of domains, and the ability to deduce new information based on the models through use of Description Logic (DL). In a step toward enabling this capability, this paper presents a cross-disciplinary data-drivenmore » control strategy for building energy management simulation that integrates semantic modeling and formal rule checking mechanisms into a Model Predictive Control (MPC) formulation. The results show that MPC provides superior levels of performance when initial conditions and inputs are derived from inference-based rules.« less

'Constraint consistency' at all orders in cosmological perturbation theory

DOE Office of Scientific and Technical Information (OSTI.GOV)

Nandi, Debottam; Shankaranarayanan, S., E-mail: debottam@iisertvm.ac.in, E-mail: shanki@iisertvm.ac.in

2015-08-01

We study the equivalence of two—order-by-order Einstein's equation and Reduced action—approaches to cosmological perturbation theory at all orders for different models of inflation. We point out a crucial consistency check which we refer to as 'Constraint consistency' condition that needs to be satisfied in order for the two approaches to lead to identical single variable equation of motion. The method we propose here is quick and efficient to check the consistency for any model including modified gravity models. Our analysis points out an important feature which is crucial for inflationary model building i.e., all 'constraint' inconsistent models have higher ordermore » Ostrogradsky's instabilities but the reverse is not true. In other words, one can have models with constraint Lapse function and Shift vector, though it may have Ostrogradsky's instabilities. We also obtain single variable equation for non-canonical scalar field in the limit of power-law inflation for the second-order perturbed variables.« less

Model Checking JAVA Programs Using Java Pathfinder

NASA Technical Reports Server (NTRS)

Havelund, Klaus; Pressburger, Thomas

2000-01-01

This paper describes a translator called JAVA PATHFINDER from JAVA to PROMELA, the "programming language" of the SPIN model checker. The purpose is to establish a framework for verification and debugging of JAVA programs based on model checking. This work should be seen in a broader attempt to make formal methods applicable "in the loop" of programming within NASA's areas such as space, aviation, and robotics. Our main goal is to create automated formal methods such that programmers themselves can apply these in their daily work (in the loop) without the need for specialists to manually reformulate a program into a different notation in order to analyze the program. This work is a continuation of an effort to formally verify, using SPIN, a multi-threaded operating system programmed in Lisp for the Deep-Space 1 spacecraft, and of previous work in applying existing model checkers and theorem provers to real applications.

Rewriting Modulo SMT

NASA Technical Reports Server (NTRS)

Rocha, Camilo; Meseguer, Jose; Munoz, Cesar A.

2013-01-01

Combining symbolic techniques such as: (i) SMT solving, (ii) rewriting modulo theories, and (iii) model checking can enable the analysis of infinite-state systems outside the scope of each such technique. This paper proposes rewriting modulo SMT as a new technique combining the powers of (i)-(iii) and ideally suited to model and analyze infinite-state open systems; that is, systems that interact with a non-deterministic environment. Such systems exhibit both internal non-determinism due to the system, and external non-determinism due to the environment. They are not amenable to finite-state model checking analysis because they typically are infinite-state. By being reducible to standard rewriting using reflective techniques, rewriting modulo SMT can both naturally model and analyze open systems without requiring any changes to rewriting-based reachability analysis techniques for closed systems. This is illustrated by the analysis of a real-time system beyond the scope of timed automata methods.

Model Checking Artificial Intelligence Based Planners: Even the Best Laid Plans Must Be Verified

NASA Technical Reports Server (NTRS)

Smith, Margaret H.; Holzmann, Gerard J.; Cucullu, Gordon C., III; Smith, Benjamin D.

2005-01-01

Automated planning systems (APS) are gaining acceptance for use on NASA missions as evidenced by APS flown On missions such as Orbiter and Deep Space 1 both of which were commanded by onboard planning systems. The planning system takes high level goals and expands them onboard into a detailed of action fiat the spacecraft executes. The system must be verified to ensure that the automatically generated plans achieve the goals as expected and do not generate actions that would harm the spacecraft or mission. These systems are typically tested using empirical methods. Formal methods, such as model checking, offer exhaustive or measurable test coverage which leads to much greater confidence in correctness. This paper describes a formal method based on the SPIN model checker. This method guarantees that possible plans meet certain desirable properties. We express the input model in Promela, the language of SPIN and express the properties of desirable plans formally.

Development of flank wear model of cutting tool by using adaptive feedback linear control system on machining AISI D2 steel and AISI 4340 steel

NASA Astrophysics Data System (ADS)

Orra, Kashfull; Choudhury, Sounak K.

2016-12-01

The purpose of this paper is to build an adaptive feedback linear control system to check the variation of cutting force signal to improve the tool life. The paper discusses the use of transfer function approach in improving the mathematical modelling and adaptively controlling the process dynamics of the turning operation. The experimental results shows to be in agreement with the simulation model and error obtained is less than 3%. The state space approach model used in this paper successfully check the adequacy of the control system through controllability and observability test matrix and can be transferred from one state to another by appropriate input control in a finite time. The proposed system can be implemented to other machining process under varying range of cutting conditions to improve the efficiency and observability of the system.

Aviation Safety: Modeling and Analyzing Complex Interactions between Humans and Automated Systems

NASA Technical Reports Server (NTRS)

Rungta, Neha; Brat, Guillaume; Clancey, William J.; Linde, Charlotte; Raimondi, Franco; Seah, Chin; Shafto, Michael

2013-01-01

The on-going transformation from the current US Air Traffic System (ATS) to the Next Generation Air Traffic System (NextGen) will force the introduction of new automated systems and most likely will cause automation to migrate from ground to air. This will yield new function allocations between humans and automation and therefore change the roles and responsibilities in the ATS. Yet, safety in NextGen is required to be at least as good as in the current system. We therefore need techniques to evaluate the safety of the interactions between humans and automation. We think that current human factor studies and simulation-based techniques will fall short in front of the ATS complexity, and that we need to add more automated techniques to simulations, such as model checking, which offers exhaustive coverage of the non-deterministic behaviors in nominal and off-nominal scenarios. In this work, we present a verification approach based both on simulations and on model checking for evaluating the roles and responsibilities of humans and automation. Models are created using Brahms (a multi-agent framework) and we show that the traditional Brahms simulations can be integrated with automated exploration techniques based on model checking, thus offering a complete exploration of the behavioral space of the scenario. Our formal analysis supports the notion of beliefs and probabilities to reason about human behavior. We demonstrate the technique with the Ueberligen accident since it exemplifies authority problems when receiving conflicting advices from human and automated systems.

Modelling and Analysis of the Excavation Phase by the Theory of Blocks Method of Tunnel 4 Kherrata Gorge, Algeria

NASA Astrophysics Data System (ADS)

Boukarm, Riadh; Houam, Abdelkader; Fredj, Mohammed; Boucif, Rima

2017-12-01

The aim of our work is to check the stability during excavation tunnel work in the rock mass of Kherrata, connecting the cities of Bejaia to Setif. The characterization methods through the Q system (method of Barton), RMR (Bieniawski classification) allowed us to conclude that the quality of rock mass is average in limestone, and poor in fractured limestone. Then modelling of excavation phase using the theory of blocks method (Software UNWEDGE) with the parameters from the recommendations of classification allowed us to check stability and to finally conclude that the use of geomechanical classification and the theory of blocks can be considered reliable in preliminary design.

Automated Assume-Guarantee Reasoning by Abstraction Refinement

NASA Technical Reports Server (NTRS)

Pasareanu, Corina S.; Giannakopoulous, Dimitra; Glannakopoulou, Dimitra

2008-01-01

Current automated approaches for compositional model checking in the assume-guarantee style are based on learning of assumptions as deterministic automata. We propose an alternative approach based on abstraction refinement. Our new method computes the assumptions for the assume-guarantee rules as conservative and not necessarily deterministic abstractions of some of the components, and refines those abstractions using counter-examples obtained from model checking them together with the other components. Our approach also exploits the alphabets of the interfaces between components and performs iterative refinement of those alphabets as well as of the abstractions. We show experimentally that our preliminary implementation of the proposed alternative achieves similar or better performance than a previous learning-based implementation.

Portable Wireless LAN Device and Two-Way Radio Threat Assessment for Aircraft VHF Communication Radio Band

NASA Technical Reports Server (NTRS)

Nguyen, Truong X.; Koppen, Sandra V.; Ely, Jay J.; Williams, Reuben A.; Smith, Laura J.; Salud, Maria Theresa P.

2004-01-01

This document summarizes the safety analysis performed on a Flight Guidance System (FGS) requirements model. In particular, the safety properties desired of the FGS model are identified and the presence of the safety properties in the model is formally verified. Chapter 1 provides an introduction to the entire project, while Chapter 2 gives a brief overview of the problem domain, the nature of accidents, model based development, and the four-variable model. Chapter 3 outlines the approach. Chapter 4 presents the results of the traditional safety analysis techniques and illustrates how the hazardous conditions associated with the system trace into specific safety properties. Chapter 5 presents the results of the formal methods analysis technique model checking that was used to verify the presence of the safety properties in the requirements model. Finally, Chapter 6 summarizes the main conclusions of the study, first and foremost that model checking is a very effective verification technique to use on discrete models with reasonable state spaces. Additional supporting details are provided in the appendices.

Cross-sectional review of the response and treatment uptake from the NHS Health Checks programme in Stoke on Trent.

PubMed

Cochrane, Thomas; Gidlow, Christopher J; Kumar, Jagdish; Mawby, Yvonne; Iqbal, Zafar; Chambers, Ruth M

2013-03-01

As part of national policy to manage the increasing burden of chronic diseases, the Department of Health in England has launched the NHS Health Checks programme, which aims to reduce the burden of the major vascular diseases on the health service. A cross-sectional review of response, attendance and treatment uptake over the first year of the programme in Stoke on Trent was carried out. Patients aged between 32 and 74 years and estimated to be at ≥20% risk of developing cardiovascular disease were identified from electronic medical records. Multi-level regression modelling was used to evaluate the influence of individual- and practice-level factors on health check outcomes. Overall 63.3% of patients responded, 43.7% attended and 29.8% took up a treatment following their health check invitation. The response was higher for older age and more affluent areas; attendance and treatment uptake were higher for males and older age. Variance between practices was significant (P < 0.001) for response (13.4%), attendance (12.7%) and uptake (23%). The attendance rate of 43.7% following invitation to a health check was considerably lower than the benchmark of 75%. The lack of public interest and the prevalence of significant comorbidity are challenges to this national policy innovation.

Probabilistic evaluation of on-line checks in fault-tolerant multiprocessor systems

NASA Technical Reports Server (NTRS)

Nair, V. S. S.; Hoskote, Yatin V.; Abraham, Jacob A.

1992-01-01

The analysis of fault-tolerant multiprocessor systems that use concurrent error detection (CED) schemes is much more difficult than the analysis of conventional fault-tolerant architectures. Various analytical techniques have been proposed to evaluate CED schemes deterministically. However, these approaches are based on worst-case assumptions related to the failure of system components. Often, the evaluation results do not reflect the actual fault tolerance capabilities of the system. A probabilistic approach to evaluate the fault detecting and locating capabilities of on-line checks in a system is developed. The various probabilities associated with the checking schemes are identified and used in the framework of the matrix-based model. Based on these probabilistic matrices, estimates for the fault tolerance capabilities of various systems are derived analytically.

Extension of specification language for soundness and completeness of service workflow

NASA Astrophysics Data System (ADS)

Viriyasitavat, Wattana; Xu, Li Da; Bi, Zhuming; Sapsomboon, Assadaporn

2018-05-01

A Service Workflow is an aggregation of distributed services to fulfill specific functionalities. With ever increasing available services, the methodologies for the selections of the services against the given requirements become main research subjects in multiple disciplines. A few of researchers have contributed to the formal specification languages and the methods for model checking; however, existing methods have the difficulties to tackle with the complexity of workflow compositions. In this paper, we propose to formalize the specification language to reduce the complexity of the workflow composition. To this end, we extend a specification language with the consideration of formal logic, so that some effective theorems can be derived for the verification of syntax, semantics, and inference rules in the workflow composition. The logic-based approach automates compliance checking effectively. The Service Workflow Specification (SWSpec) has been extended and formulated, and the soundness, completeness, and consistency of SWSpec applications have been verified; note that a logic-based SWSpec is mandatory for the development of model checking. The application of the proposed SWSpec has been demonstrated by the examples with the addressed soundness, completeness, and consistency.

From Care to Cure: Demonstrating a Model of Clinical Patient Navigation for Hepatitis C Care and Treatment in High-Need Patients.

PubMed

Ford, Mary M; Johnson, Nirah; Desai, Payal; Rude, Eric; Laraque, Fabienne

2017-03-01

The NYC Department of Health implemented a patient navigation program, Check Hep C, to address patient and provider barriers to HCV care and potentially lifesaving treatment. Services were delivered at two clinical care sites and two sites that linked patients to off-site care. Working with a multidisciplinary care team, patient navigators provided risk assessment, health education, treatment readiness and medication adherence counseling, and medication coordination. Between March 2014 and January 2015, 388 participants enrolled in Check Hep C, 129 (33%) initiated treatment, and 119 (91% of initiators) had sustained virologic response (SVR). Participants receiving on-site clinical care had higher odds of initiating treatment than those linked to off-site care. Check Hep C successfully supported high-need participants through HCV care and treatment, and SVR rates demonstrate the real-world ability of achieving high cure rates using patient navigation care models. © The Author 2016. Published by Oxford University Press for the Infectious Diseases Society of America. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

NASTRAN data generation and management using interactive graphics

NASA Technical Reports Server (NTRS)

Smootkatow, M.; Cooper, B. M.

1972-01-01

A method of using an interactive graphics device to generate a large portion of the input bulk data with visual checks of the structure and the card images is described. The generation starts from GRID and PBAR cards. The visual checks result from a three-dimensional display of the model in any rotated position. By detailing the steps, the time saving and cost effectiveness of this method may be judged, and its potential as a useful tool for the structural analyst may be established.

Development of Subischial Prosthetic Sockets with Vacuum-Assisted Suspension for Highly Active Persons with Transfemoral Amputations

DTIC Science & Technology

2016-12-01

of the frame from the combined image files and ensure total contact between the frame geometry, ultimately modeled independently as a solid, and...fitting with a rigid PETG check socket to ensure correct volumes and total contact at the distal end has been achieved, a second check socket can be...from dynamically conforming to changes in residual limb shape and volume during gait (Sanders, 2009). The ensuing separation (i.e. loss of contact

Extensions to the visual predictive check to facilitate model performance evaluation.

PubMed

Post, Teun M; Freijer, Jan I; Ploeger, Bart A; Danhof, Meindert

2008-04-01

The Visual Predictive Check (VPC) is a valuable and supportive instrument for evaluating model performance. However in its most commonly applied form, the method largely depends on a subjective comparison of the distribution of the simulated data with the observed data, without explicitly quantifying and relating the information in both. In recent adaptations to the VPC this drawback is taken into consideration by presenting the observed and predicted data as percentiles. In addition, in some of these adaptations the uncertainty in the predictions is represented visually. However, it is not assessed whether the expected random distribution of the observations around the predicted median trend is realised in relation to the number of observations. Moreover the influence of and the information residing in missing data at each time point is not taken into consideration. Therefore, in this investigation the VPC is extended with two methods to support a less subjective and thereby more adequate evaluation of model performance: (i) the Quantified Visual Predictive Check (QVPC) and (ii) the Bootstrap Visual Predictive Check (BVPC). The QVPC presents the distribution of the observations as a percentage, thus regardless the density of the data, above and below the predicted median at each time point, while also visualising the percentage of unavailable data. The BVPC weighs the predicted median against the 5th, 50th and 95th percentiles resulting from a bootstrap of the observed data median at each time point, while accounting for the number and the theoretical position of unavailable data. The proposed extensions to the VPC are illustrated by a pharmacokinetic simulation example and applied to a pharmacodynamic disease progression example.

A Categorization of Dynamic Analyzers

NASA Technical Reports Server (NTRS)

Lujan, Michelle R.

1997-01-01

Program analysis techniques and tools are essential to the development process because of the support they provide in detecting errors and deficiencies at different phases of development. The types of information rendered through analysis includes the following: statistical measurements of code, type checks, dataflow analysis, consistency checks, test data,verification of code, and debugging information. Analyzers can be broken into two major categories: dynamic and static. Static analyzers examine programs with respect to syntax errors and structural properties., This includes gathering statistical information on program content, such as the number of lines of executable code, source lines. and cyclomatic complexity. In addition, static analyzers provide the ability to check for the consistency of programs with respect to variables. Dynamic analyzers in contrast are dependent on input and the execution of a program providing the ability to find errors that cannot be detected through the use of static analysis alone. Dynamic analysis provides information on the behavior of a program rather than on the syntax. Both types of analysis detect errors in a program, but dynamic analyzers accomplish this through run-time behavior. This paper focuses on the following broad classification of dynamic analyzers: 1) Metrics; 2) Models; and 3) Monitors. Metrics are those analyzers that provide measurement. The next category, models, captures those analyzers that present the state of the program to the user at specified points in time. The last category, monitors, checks specified code based on some criteria. The paper discusses each classification and the techniques that are included under them. In addition, the role of each technique in the software life cycle is discussed. Familiarization with the tools that measure, model and monitor programs provides a framework for understanding the program's dynamic behavior from different, perspectives through analysis of the input/output data.

Retrospective checking of compliance with practice guidelines for acute stroke care: a novel experiment using openEHR’s Guideline Definition Language

PubMed Central

2014-01-01

Background Providing scalable clinical decision support (CDS) across institutions that use different electronic health record (EHR) systems has been a challenge for medical informatics researchers. The lack of commonly shared EHR models and terminology bindings has been recognised as a major barrier to sharing CDS content among different organisations. The openEHR Guideline Definition Language (GDL) expresses CDS content based on openEHR archetypes and can support any clinical terminologies or natural languages. Our aim was to explore in an experimental setting the practicability of GDL and its underlying archetype formalism. A further aim was to report on the artefacts produced by this new technological approach in this particular experiment. We modelled and automatically executed compliance checking rules from clinical practice guidelines for acute stroke care. Methods We extracted rules from the European clinical practice guidelines as well as from treatment contraindications for acute stroke care and represented them using GDL. Then we executed the rules retrospectively on 49 mock patient cases to check the cases’ compliance with the guidelines, and manually validated the execution results. We used openEHR archetypes, GDL rules, the openEHR reference information model, reference terminologies and the Data Archetype Definition Language. We utilised the open-sourced GDL Editor for authoring GDL rules, the international archetype repository for reusing archetypes, the open-sourced Ocean Archetype Editor for authoring or modifying archetypes and the CDS Workbench for executing GDL rules on patient data. Results We successfully represented clinical rules about 14 out of 19 contraindications for thrombolysis and other aspects of acute stroke care with 80 GDL rules. These rules are based on 14 reused international archetypes (one of which was modified), 2 newly created archetypes and 51 terminology bindings (to three terminologies). Our manual compliance checks for 49 mock patients were a complete match versus the automated compliance results. Conclusions Shareable guideline knowledge for use in automated retrospective checking of guideline compliance may be achievable using GDL. Whether the same GDL rules can be used for at-the-point-of-care CDS remains unknown. PMID:24886468

Algebraic model checking for Boolean gene regulatory networks.

PubMed

Tran, Quoc-Nam

2011-01-01

We present a computational method in which modular and Groebner bases (GB) computation in Boolean rings are used for solving problems in Boolean gene regulatory networks (BN). In contrast to other known algebraic approaches, the degree of intermediate polynomials during the calculation of Groebner bases using our method will never grow resulting in a significant improvement in running time and memory space consumption. We also show how calculation in temporal logic for model checking can be done by means of our direct and efficient Groebner basis computation in Boolean rings. We present our experimental results in finding attractors and control strategies of Boolean networks to illustrate our theoretical arguments. The results are promising. Our algebraic approach is more efficient than the state-of-the-art model checker NuSMV on BNs. More importantly, our approach finds all solutions for the BN problems.

SimCheck: An Expressive Type System for Simulink

NASA Technical Reports Server (NTRS)

Roy, Pritam; Shankar, Natarajan

2010-01-01

MATLAB Simulink is a member of a class of visual languages that are used for modeling and simulating physical and cyber-physical systems. A Simulink model consists of blocks with input and output ports connected using links that carry signals. We extend the type system of Simulink with annotations and dimensions/units associated with ports and links. These types can capture invariants on signals as well as relations between signals. We define a type-checker that checks the wellformedness of Simulink blocks with respect to these type annotations. The type checker generates proof obligations that are solved by SRI's Yices solver for satisfiability modulo theories (SMT). This translation can be used to detect type errors, demonstrate counterexamples, generate test cases, or prove the absence of type errors. Our work is an initial step toward the symbolic analysis of MATLAB Simulink models.

Computational technique for stepwise quantitative assessment of equation correctness

NASA Astrophysics Data System (ADS)

Othman, Nuru'l Izzah; Bakar, Zainab Abu

2017-04-01

Many of the computer-aided mathematics assessment systems that are available today possess the capability to implement stepwise correctness checking of a working scheme for solving equations. The computational technique for assessing the correctness of each response in the scheme mainly involves checking the mathematical equivalence and providing qualitative feedback. This paper presents a technique, known as the Stepwise Correctness Checking and Scoring (SCCS) technique that checks the correctness of each equation in terms of structural equivalence and provides quantitative feedback. The technique, which is based on the Multiset framework, adapts certain techniques from textual information retrieval involving tokenization, document modelling and similarity evaluation. The performance of the SCCS technique was tested using worked solutions on solving linear algebraic equations in one variable. 350 working schemes comprising of 1385 responses were collected using a marking engine prototype, which has been developed based on the technique. The results show that both the automated analytical scores and the automated overall scores generated by the marking engine exhibit high percent agreement, high correlation and high degree of agreement with manual scores with small average absolute and mixed errors.

Specification and Verification of Web Applications in Rewriting Logic

NASA Astrophysics Data System (ADS)

Alpuente, María; Ballis, Demis; Romero, Daniel

This paper presents a Rewriting Logic framework that formalizes the interactions between Web servers and Web browsers through a communicating protocol abstracting HTTP. The proposed framework includes a scripting language that is powerful enough to model the dynamics of complex Web applications by encompassing the main features of the most popular Web scripting languages (e.g. PHP, ASP, Java Servlets). We also provide a detailed characterization of browser actions (e.g. forward/backward navigation, page refresh, and new window/tab openings) via rewrite rules, and show how our models can be naturally model-checked by using the Linear Temporal Logic of Rewriting (LTLR), which is a Linear Temporal Logic specifically designed for model-checking rewrite theories. Our formalization is particularly suitable for verification purposes, since it allows one to perform in-depth analyses of many subtle aspects related to Web interaction. Finally, the framework has been completely implemented in Maude, and we report on some successful experiments that we conducted by using the Maude LTLR model-checker.

Experimental Evaluation of a Planning Language Suitable for Formal Verification

NASA Technical Reports Server (NTRS)

Butler, Rick W.; Munoz, Cesar A.; Siminiceanu, Radu I.

2008-01-01

The marriage of model checking and planning faces two seemingly diverging alternatives: the need for a planning language expressive enough to capture the complexity of real-life applications, as opposed to a language simple, yet robust enough to be amenable to exhaustive verification and validation techniques. In an attempt to reconcile these differences, we have designed an abstract plan description language, ANMLite, inspired from the Action Notation Modeling Language (ANML) [17]. We present the basic concepts of the ANMLite language as well as an automatic translator from ANMLite to the model checker SAL (Symbolic Analysis Laboratory) [7]. We discuss various aspects of specifying a plan in terms of constraints and explore the implications of choosing a robust logic behind the specification of constraints, rather than simply propose a new planning language. Additionally, we provide an initial assessment of the efficiency of model checking to search for solutions of planning problems. To this end, we design a basic test benchmark and study the scalability of the generated SAL models in terms of plan complexity.

Formal Verification of the Runway Safety Monitor

NASA Technical Reports Server (NTRS)

Siminiceanu, Radu; Ciardo, Gianfranco

2006-01-01

The Runway Safety Monitor (RSM) designed by Lockheed Martin is part of NASA's effort to reduce runway accidents. We developed a Petri net model of the RSM protocol and used the model checking functions of our tool SMART to investigate a number of safety properties in RSM. To mitigate the impact of state-space explosion, we built a highly discretized model of the system, obtained by partitioning the monitored runway zone into a grid of smaller volumes and by considering scenarios involving only two aircraft. The model also assumes that there are no communication failures, such as bad input from radar or lack of incoming data, thus it relies on a consistent view of reality by all participants. In spite of these simplifications, we were able to expose potential problems in the RSM conceptual design. Our findings were forwarded to the design engineers, who undertook corrective action. Additionally, the results stress the efficiency attained by the new model checking algorithms implemented in SMART, and demonstrate their applicability to real-world systems.

Cognitive Style Mapping at Mt. Hood Community College.

ERIC Educational Resources Information Center

Keyser, John S.

1980-01-01

Describes Mount Hood Community College's experiences using the Modified Hill Model for Cognitive Style Mapping (CSM). Enumerates the nine dimensions of cognitive style assessed by the model. Discusses the value and limitations of CSM, five major checks on the validity of the model, and Mount Hood faculty's involvement with CSM. (AYC)

Scaling in the Donangelo-Sneppen model for evolution of money

NASA Astrophysics Data System (ADS)

Stauffer, Dietrich; P. Radomski, Jan

2001-03-01

The evolution of money from unsuccessful barter attempts, as modeled by Donangelo and Sneppen, is modified by a deterministic instead of a probabilistic selection of the most desired product as money. We check in particular the characteristic times of the model as a function of system size.

On the Estimation of Standard Errors in Cognitive Diagnosis Models

ERIC Educational Resources Information Center

Philipp, Michel; Strobl, Carolin; de la Torre, Jimmy; Zeileis, Achim

2018-01-01

Cognitive diagnosis models (CDMs) are an increasingly popular method to assess mastery or nonmastery of a set of fine-grained abilities in educational or psychological assessments. Several inference techniques are available to quantify the uncertainty of model parameter estimates, to compare different versions of CDMs, or to check model…

The Future of Political Communication Research: A Japanese Perspective.

ERIC Educational Resources Information Center

Youichi, Ito

1993-01-01

Introduces two Japanese models of mass media effects: (1) the "joho kohdo" (information behavior) model which suggests that people use extracted information to check the credibility of mass media information; and (2) the tripolar "kuuki" model which suggests that the mass media have effects as part of the triadic relationship…

The microcomputer scientific software series 2: general linear model--regression.

Treesearch

Harold M. Rauscher

1983-01-01

The general linear model regression (GLMR) program provides the microcomputer user with a sophisticated regression analysis capability. The output provides a regression ANOVA table, estimators of the regression model coefficients, their confidence intervals, confidence intervals around the predicted Y-values, residuals for plotting, a check for multicollinearity, a...

Analysis of DIRAC's behavior using model checking with process algebra

NASA Astrophysics Data System (ADS)

Remenska, Daniela; Templon, Jeff; Willemse, Tim; Bal, Henri; Verstoep, Kees; Fokkink, Wan; Charpentier, Philippe; Graciani Diaz, Ricardo; Lanciotti, Elisa; Roiser, Stefan; Ciba, Krzysztof

2012-12-01

DIRAC is the grid solution developed to support LHCb production activities as well as user data analysis. It consists of distributed services and agents delivering the workload to the grid resources. Services maintain database back-ends to store dynamic state information of entities such as jobs, queues, staging requests, etc. Agents use polling to check and possibly react to changes in the system state. Each agent's logic is relatively simple; the main complexity lies in their cooperation. Agents run concurrently, and collaborate using the databases as shared memory. The databases can be accessed directly by the agents if running locally or through a DIRAC service interface if necessary. This shared-memory model causes entities to occasionally get into inconsistent states. Tracing and fixing such problems becomes formidable due to the inherent parallelism present. We propose more rigorous methods to cope with this. Model checking is one such technique for analysis of an abstract model of a system. Unlike conventional testing, it allows full control over the parallel processes execution, and supports exhaustive state-space exploration. We used the mCRL2 language and toolset to model the behavior of two related DIRAC subsystems: the workload and storage management system. Based on process algebra, mCRL2 allows defining custom data types as well as functions over these. This makes it suitable for modeling the data manipulations made by DIRAC's agents. By visualizing the state space and replaying scenarios with the toolkit's simulator, we have detected race-conditions and deadlocks in these systems, which, in several cases, were confirmed to occur in the reality. Several properties of interest were formulated and verified with the tool. Our future direction is automating the translation from DIRAC to a formal model.

The Effects of Check-In, Check-Up, Check-Out for Students with Moderate Intellectual Disability during On- and Off-Site Vocational Training

ERIC Educational Resources Information Center

Boden, Lauren J.; Jolivette, Kristine; Alberto, Paul A.

2018-01-01

Check-in/check-out is a secondary-tier intervention within the positive behavior interventions and supports framework. Check-in/check-out pairs the use of an adult mentor with a daily progress report to help students meet individualized behavioral goals. This study adds to the research base by examining the effects of check-in, check-up, check-out…

Enabling model checking for collaborative process analysis: from BPMN to `Network of Timed Automata'

NASA Astrophysics Data System (ADS)

Mallek, Sihem; Daclin, Nicolas; Chapurlat, Vincent; Vallespir, Bruno

2015-04-01

Interoperability is a prerequisite for partners involved in performing collaboration. As a consequence, the lack of interoperability is now considered a major obstacle. The research work presented in this paper aims to develop an approach that allows specifying and verifying a set of interoperability requirements to be satisfied by each partner in the collaborative process prior to process implementation. To enable the verification of these interoperability requirements, it is necessary first and foremost to generate a model of the targeted collaborative process; for this research effort, the standardised language BPMN 2.0 is used. Afterwards, a verification technique must be introduced, and model checking is the preferred option herein. This paper focuses on application of the model checker UPPAAL in order to verify interoperability requirements for the given collaborative process model. At first, this step entails translating the collaborative process model from BPMN into a UPPAAL modelling language called 'Network of Timed Automata'. Second, it becomes necessary to formalise interoperability requirements into properties with the dedicated UPPAAL language, i.e. the temporal logic TCTL.

31 CFR 240.3 - Electronic checks and substitute checks.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 31 Money and Finance: Treasury 2 2010-07-01 2010-07-01 false Electronic checks and substitute... OF CHECKS DRAWN ON THE UNITED STATES TREASURY General Provisions § 240.3 Electronic checks and substitute checks. (a) Legal equivalence of electronic checks. An electronic check for which a presenting...

31 CFR 240.3 - Electronic checks and substitute checks.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 31 Money and Finance:Treasury 2 2011-07-01 2011-07-01 false Electronic checks and substitute... OF CHECKS DRAWN ON THE UNITED STATES TREASURY General Provisions § 240.3 Electronic checks and substitute checks. (a) Legal equivalence of electronic checks. An electronic check for which a presenting...

31 CFR 240.3 - Electronic checks and substitute checks.

Code of Federal Regulations, 2012 CFR

2012-07-01

... 31 Money and Finance:Treasury 2 2012-07-01 2012-07-01 false Electronic checks and substitute... OF CHECKS DRAWN ON THE UNITED STATES TREASURY General Provisions § 240.3 Electronic checks and substitute checks. (a) Legal equivalence of electronic checks. An electronic check for which a presenting...

Automatic Rail Extraction and Celarance Check with a Point Cloud Captured by Mls in a Railway

NASA Astrophysics Data System (ADS)

Niina, Y.; Honma, R.; Honma, Y.; Kondo, K.; Tsuji, K.; Hiramatsu, T.; Oketani, E.

2018-05-01

Recently, MLS (Mobile Laser Scanning) has been successfully used in a road maintenance. In this paper, we present the application of MLS for the inspection of clearance along railway tracks of West Japan Railway Company. Point clouds around the track are captured by MLS mounted on a bogie and rail position can be determined by matching the shape of the ideal rail head with respect to the point cloud by ICP algorithm. A clearance check is executed automatically with virtual clearance model laid along the extracted rail. As a result of evaluation, the accuracy of extracting rail positions is less than 3 mm. With respect to the automatic clearance check, the objects inside the clearance and the ones related to a contact line is successfully detected by visual confirmation.

A Note on Item-Restscore Association in Rasch Models

ERIC Educational Resources Information Center

Kreiner, Svend

2011-01-01

To rule out the need for a two-parameter item response theory (IRT) model during item analysis by Rasch models, it is important to check the Rasch model's assumption that all items have the same item discrimination. Biserial and polyserial correlation coefficients measuring the association between items and restscores are often used in an informal…

Rasch Mixture Models for DIF Detection: A Comparison of Old and New Score Specifications

ERIC Educational Resources Information Center

Frick, Hannah; Strobl, Carolin; Zeileis, Achim

2015-01-01

Rasch mixture models can be a useful tool when checking the assumption of measurement invariance for a single Rasch model. They provide advantages compared to manifest differential item functioning (DIF) tests when the DIF groups are only weakly correlated with the manifest covariates available. Unlike in single Rasch models, estimation of Rasch…

Modelling spoilage of fresh turbot and evaluation of a time-temperature integrator (TTI) label under fluctuating temperature.

PubMed

Nuin, Maider; Alfaro, Begoña; Cruz, Ziortza; Argarate, Nerea; George, Susie; Le Marc, Yvan; Olley, June; Pin, Carmen

2008-10-31

Kinetic models were developed to predict the microbial spoilage and the sensory quality of fresh fish and to evaluate the efficiency of a commercial time-temperature integrator (TTI) label, Fresh Check(R), to monitor shelf life. Farmed turbot (Psetta maxima) samples were packaged in PVC film and stored at 0, 5, 10 and 15 degrees C. Microbial growth and sensory attributes were monitored at regular time intervals. The response of the Fresh Check device was measured at the same temperatures during the storage period. The sensory perception was quantified according to a global sensory indicator obtained by principal component analysis as well as to the Quality Index Method, QIM, as described by Rahman and Olley [Rahman, H.A., Olley, J., 1984. Assessment of sensory techniques for quality assessment of Australian fish. CSIRO Tasmanian Regional Laboratory. Occasional paper n. 8. Available from the Australian Maritime College library. Newnham. Tasmania]. Both methods were found equally valid to monitor the loss of sensory quality. The maximum specific growth rate of spoilage bacteria, the rate of change of the sensory indicators and the rate of change of the colour measurements of the TTI label were modelled as a function of temperature. The temperature had a similar effect on the bacteria, sensory and Fresh Check kinetics. At the time of sensory rejection, the bacterial load was ca. 10(5)-10(6) cfu/g. The end of shelf life indicated by the Fresh Check label was close to the sensory rejection time. The performance of the models was validated under fluctuating temperature conditions by comparing the predicted and measured values for all microbial, sensory and TTI responses. The models have been implemented in a Visual Basic add-in for Excel called "Fish Shelf Life Prediction (FSLP)". This program predicts sensory acceptability and growth of spoilage bacteria in fish and the response of the TTI at constant and fluctuating temperature conditions. The program is freely available at http://www.azti.es/muestracontenido.asp?idcontenido=980&content=15&nodo1=30&nodo2=0.

Modeling the Arden Syntax for medical decisions in XML.

PubMed

Kim, Sukil; Haug, Peter J; Rocha, Roberto A; Choi, Inyoung

2008-10-01

A new model expressing Arden Syntax with the eXtensible Markup Language (XML) was developed to increase its portability. Every example was manually parsed and reviewed until the schema and the style sheet were considered to be optimized. When the first schema was finished, several MLMs in Arden Syntax Markup Language (ArdenML) were validated against the schema. They were then transformed to HTML formats with the style sheet, during which they were compared to the original text version of their own MLM. When faults were found in the transformed MLM, the schema and/or style sheet was fixed. This cycle continued until all the examples were encoded into XML documents. The original MLMs were encoded in XML according to the proposed XML schema and reverse-parsed MLMs in ArdenML were checked using a public domain Arden Syntax checker. Two hundred seventy seven examples of MLMs were successfully transformed into XML documents using the model, and the reverse-parse yielded the original text version of MLMs. Two hundred sixty five of the 277 MLMs showed the same error patterns before and after transformation, and all 11 errors related to statement structure were resolved in XML version. The model uses two syntax checking mechanisms, first an XML validation process, and second, a syntax check using an XSL style sheet. Now that we have a schema for ArdenML, we can also begin the development of style sheets for transformation ArdenML into other languages.

30 CFR 57.11058 - Check-in, check-out system.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Check-in, check-out system. 57.11058 Section 57... Escapeways Escapeways-Underground Only § 57.11058 Check-in, check-out system. Each operator of an underground mine shall establish a check-in and check-out system which shall provide an accurate record of persons...

30 CFR 57.11058 - Check-in, check-out system.

Code of Federal Regulations, 2014 CFR

2014-07-01

... 30 Mineral Resources 1 2014-07-01 2014-07-01 false Check-in, check-out system. 57.11058 Section 57... Escapeways Escapeways-Underground Only § 57.11058 Check-in, check-out system. Each operator of an underground mine shall establish a check-in and check-out system which shall provide an accurate record of persons...

30 CFR 57.11058 - Check-in, check-out system.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 30 Mineral Resources 1 2011-07-01 2011-07-01 false Check-in, check-out system. 57.11058 Section 57... Escapeways Escapeways-Underground Only § 57.11058 Check-in, check-out system. Each operator of an underground mine shall establish a check-in and check-out system which shall provide an accurate record of persons...

30 CFR 57.11058 - Check-in, check-out system.

Code of Federal Regulations, 2013 CFR

2013-07-01

... 30 Mineral Resources 1 2013-07-01 2013-07-01 false Check-in, check-out system. 57.11058 Section 57... Escapeways Escapeways-Underground Only § 57.11058 Check-in, check-out system. Each operator of an underground mine shall establish a check-in and check-out system which shall provide an accurate record of persons...

30 CFR 57.11058 - Check-in, check-out system.

Code of Federal Regulations, 2012 CFR

2012-07-01

... 30 Mineral Resources 1 2012-07-01 2012-07-01 false Check-in, check-out system. 57.11058 Section 57... Escapeways Escapeways-Underground Only § 57.11058 Check-in, check-out system. Each operator of an underground mine shall establish a check-in and check-out system which shall provide an accurate record of persons...

SWAT Check: A screening tool to assist users in the identification of potential model application problems

USDA-ARS?s Scientific Manuscript database

The Soil and Water Assessment Tool (SWAT) is a basin scale hydrologic model developed by the US Department of Agriculture-Agricultural Research Service. SWAT's broad applicability, user friendly model interfaces, and automatic calibration software have led to a rapid increase in the number of new u...

Volatility in GARCH Models of Business Tendency Index

NASA Astrophysics Data System (ADS)

Wahyuni, Dwi A. S.; Wage, Sutarman; Hartono, Ateng

2018-01-01

This paper aims to obtain a model of business tendency index by considering volatility factor. Volatility factor detected by ARCH (Autoregressive Conditional Heteroscedasticity). The ARCH checking was performed using the Lagrange multiplier test. The modeling is Generalized Autoregressive Conditional Heteroscedasticity (GARCH) are able to overcome volatility problems by incorporating past residual elements and residual variants.

An efficient algorithm for computing fixed length attractors based on bounded model checking in synchronous Boolean networks with biochemical applications.

PubMed

Li, X Y; Yang, G W; Zheng, D S; Guo, W S; Hung, W N N

2015-04-28

Genetic regulatory networks are the key to understanding biochemical systems. One condition of the genetic regulatory network under different living environments can be modeled as a synchronous Boolean network. The attractors of these Boolean networks will help biologists to identify determinant and stable factors. Existing methods identify attractors based on a random initial state or the entire state simultaneously. They cannot identify the fixed length attractors directly. The complexity of including time increases exponentially with respect to the attractor number and length of attractors. This study used the bounded model checking to quickly locate fixed length attractors. Based on the SAT solver, we propose a new algorithm for efficiently computing the fixed length attractors, which is more suitable for large Boolean networks and numerous attractors' networks. After comparison using the tool BooleNet, empirical experiments involving biochemical systems demonstrated the feasibility and efficiency of our approach.

MRO Sequence Checking Tool

NASA Technical Reports Server (NTRS)

Fisher, Forest; Gladden, Roy; Khanampornpan, Teerapat

2008-01-01

The MRO Sequence Checking Tool program, mro_check, automates significant portions of the MRO (Mars Reconnaissance Orbiter) sequence checking procedure. Though MRO has similar checks to the ODY s (Mars Odyssey) Mega Check tool, the checks needed for MRO are unique to the MRO spacecraft. The MRO sequence checking tool automates the majority of the sequence validation procedure and check lists that are used to validate the sequences generated by MRO MPST (mission planning and sequencing team). The tool performs more than 50 different checks on the sequence. The automation varies from summarizing data about the sequence needed for visual verification of the sequence, to performing automated checks on the sequence and providing a report for each step. To allow for the addition of new checks as needed, this tool is built in a modular fashion.

Assessment of sediment yield in a sloping Mediterranean watershed in Cyprus

NASA Astrophysics Data System (ADS)

Djuma, Hakan; Bruggeman, Adriana; Camera, Corrado

2014-05-01

In the Mediterranean region, water catchment sediment yield as a result of erosion is higher than in many other regions in Europe due to the climatic conditions, topography, lithology and land-use. Modelling sediment transport is difficult due to intermittent stream flow and highly irregular rainfall conditions in this region. The objective of this study is to quantify sediment yield of a highly sloping Mediterranean environment. This study is conducted in the Peristerona Watershed in Cyprus, which has ephemeral water flow. In the downstream area a series of check dams have been placed across the stream to slow the flow and increase groundwater recharge. The surface area of the watershed, upstream of the check dams, is 103 km2 with elevation changing between 1540 m and 280 m and a mean local slope higher than 40% for the mountainous part and lower than 8% for the plain. The long-term average annual precipitation ranges from 755 mm in the upstream area to 276 mm in the plain. The surface extent of the sediment that was deposited at the most upstream check dam during two seasons was measured with a Differential Global Positioning System. The depth of the sediment was measured with utility poles and bulk density samples from the sediment profile were collected. The sediment had a surface area of 12600 m2 and an average depth of 0.23 m. The mean of the sediment dry bulk density samples was 1.05 t m-3 with a standard deviation of 0.11. Based on these values, area specific sediment yield was computed as 1 t ha-1 per year for the entire catchment area upstream of the check dam, assuming a check dam sediment trap efficiency of 15%. Erosion in the watershed is currently modeled with PESERA using detailed watershed data.

Comparison of hot versus cold boning of beef carcasses on bacterial growth and the risk of blown pack spoilage.

PubMed

Reid, Rachael; Fanning, Séamus; Whyte, Paul; Kerry, Joe; Bolton, Declan

2017-03-01

Primals were prepared from beef Longissimus thoracis et lumborum (LTL), psoas major (PM), quadriceps femoris (QF) and semitendinosus (S) muscles from cold and hot boned carcasses, vacuum-packaged and stored for 42 or 100days at 2°C and 7°C. Storage temperature, carcass or primal surface temperature, pH and a w were monitored. Samples were taken periodically and tested for total viable count mesophilic (TVCm), TVC psychrophilic (TVCp), total Enterobacteriaceae count (TEC), presumptive Pseudomonas spp., lactic acid bacteria (LAB), Clostridium spp. and Brochothrix thermosphacta. A fifth muscle, biceps femoris (BF), was used to examine the impact of hot boning on blown pack spoilage (BPS). Primal counts increased to 6-7log 10 cfucm -2 after 6weeks. Significantly (P<0.05) higher TEC, Pseudomonas spp. and Br. thermosphacta counts were observed on cold versus hot boned primals. In contrast, significantly (P<0.05) higher TVC, LAB and Clostridium spp. concentrations were obtained on hot boned beef. Moreover, BPS pack distension/bursting occurred considerably sooner in hot boned product. Copyright © 2016 Elsevier Ltd. All rights reserved.

A comparison of the carcass and meat quality of Martina Franca donkey foals aged 8 or 12 months.

PubMed

Polidori, Paolo; Pucciarelli, Stefania; Ariani, Ambra; Polzonetti, Valeria; Vincenzetti, Silvia

2015-08-01

The effects of slaughter age (8 vs 12 months) were investigated on meat and carcass quality obtained from Martina Franca donkey foals. Sixteen male foals were used, eight were slaughtered at 8 months of age with a mean (±s.e.) final body weight of 101±18kg and the remaining 8 foals slaughtered at 12 months of age with a mean final body weight of 122±13kg. Carcass weight and dressing percentage were higher (P<0.05) in older foals. Shear force value was lower (P<0.05) in donkeys slaughtered at 8 months of age (54.03N) compared to the same muscle Longissimus Thoracis et Lumborum (LTL) collected in older animals (62.66N). Muscle glycogen content was higher (P<0.05) in foals slaughtered at 12months of age. Donkey foal meat showed an interesting content of essential amino acids and a notable percentage of unsaturated fatty acids in both groups of animals, giving a high nutritional value to this alternative red meat. Copyright © 2015 Elsevier Ltd. All rights reserved.

The effect of carbon monoxide pretreatment exposure time on the colour stability and quality attributes of vacuum packaged beef steaks.

PubMed

Van Rooyen, Lauren Anne; Allen, Paul; Crawley, Sarah M; O'Connor, David I

2017-07-01

The effect of 5% CO pretreatments prior to vacuum packaging of beef striploin steaks (Longissimus thoracis et lumborum, LTL) on quality attributes, primarily colour stability was investigated. The aim was to determine the optimum pretreatment that would induce the desirable red colour, while allowing discoloration to occur by the end of a 28-day display period (2°C), so as to not mask spoilage. A range of pretreatment exposure times (1, 3, 5, 7, 9, 15 and 24h) were applied to steaks using a gas mixture of 5% CO, 60% CO 2 and 35% N 2 . The 5h CO pretreatment exposure time achieved the desirable colour and discoloration reached unacceptable levels (a*=12, C*=16) by the use-by date (28days), thus ensuring consumers' of a reliable visual indication of freshness and addressing concerns about safety. The 5% CO pretreatment had no negative effect on microbiological safety, lipid oxidation, cooking loss and WBSF measurements at the end of storage (P>0.05). Copyright © 2017 Elsevier Ltd. All rights reserved.

A digital system for surface reconstruction

USGS Publications Warehouse

Zhou, Weiyang; Brock, Robert H.; Hopkins, Paul F.

1996-01-01

A digital photogrammetric system, STEREO, was developed to determine three dimensional coordinates of points of interest (POIs) defined with a grid on a textureless and smooth-surfaced specimen. Two CCD cameras were set up with unknown orientation and recorded digital images of a reference model and a specimen. Points on the model were selected as control or check points for calibrating or assessing the system. A new algorithm for edge-detection called local maximum convolution (LMC) helped extract the POIs from the stereo image pairs. The system then matched the extracted POIs and used a least squares “bundle” adjustment procedure to solve for the camera orientation parameters and the coordinates of the POIs. An experiment with STEREO found that the standard deviation of the residuals at the check points was approximately 24%, 49% and 56% of the pixel size in the X, Y and Z directions, respectively. The average of the absolute values of the residuals at the check points was approximately 19%, 36% and 49% of the pixel size in the X, Y and Z directions, respectively. With the graphical user interface, STEREO demonstrated a high degree of automation and its operation does not require special knowledge of photogrammetry, computers or image processing.

Road sign recognition with fuzzy adaptive pre-processing models.

PubMed

Lin, Chien-Chuan; Wang, Ming-Shi

2012-01-01

A road sign recognition system based on adaptive image pre-processing models using two fuzzy inference schemes has been proposed. The first fuzzy inference scheme is to check the changes of the light illumination and rich red color of a frame image by the checking areas. The other is to check the variance of vehicle's speed and angle of steering wheel to select an adaptive size and position of the detection area. The Adaboost classifier was employed to detect the road sign candidates from an image and the support vector machine technique was employed to recognize the content of the road sign candidates. The prohibitory and warning road traffic signs are the processing targets in this research. The detection rate in the detection phase is 97.42%. In the recognition phase, the recognition rate is 93.04%. The total accuracy rate of the system is 92.47%. For video sequences, the best accuracy rate is 90.54%, and the average accuracy rate is 80.17%. The average computing time is 51.86 milliseconds per frame. The proposed system can not only overcome low illumination and rich red color around the road sign problems but also offer high detection rates and high computing performance.

Road Sign Recognition with Fuzzy Adaptive Pre-Processing Models

PubMed Central

Lin, Chien-Chuan; Wang, Ming-Shi

2012-01-01

A road sign recognition system based on adaptive image pre-processing models using two fuzzy inference schemes has been proposed. The first fuzzy inference scheme is to check the changes of the light illumination and rich red color of a frame image by the checking areas. The other is to check the variance of vehicle's speed and angle of steering wheel to select an adaptive size and position of the detection area. The Adaboost classifier was employed to detect the road sign candidates from an image and the support vector machine technique was employed to recognize the content of the road sign candidates. The prohibitory and warning road traffic signs are the processing targets in this research. The detection rate in the detection phase is 97.42%. In the recognition phase, the recognition rate is 93.04%. The total accuracy rate of the system is 92.47%. For video sequences, the best accuracy rate is 90.54%, and the average accuracy rate is 80.17%. The average computing time is 51.86 milliseconds per frame. The proposed system can not only overcome low illumination and rich red color around the road sign problems but also offer high detection rates and high computing performance. PMID:22778650

Predictive modeling of addiction lapses in a mobile health application.

PubMed

Chih, Ming-Yuan; Patton, Timothy; McTavish, Fiona M; Isham, Andrew J; Judkins-Fisher, Chris L; Atwood, Amy K; Gustafson, David H

2014-01-01

The chronically relapsing nature of alcoholism leads to substantial personal, family, and societal costs. Addiction-comprehensive health enhancement support system (A-CHESS) is a smartphone application that aims to reduce relapse. To offer targeted support to patients who are at risk of lapses within the coming week, a Bayesian network model to predict such events was constructed using responses on 2,934 weekly surveys (called the Weekly Check-in) from 152 alcohol-dependent individuals who recently completed residential treatment. The Weekly Check-in is a self-monitoring service, provided in A-CHESS, to track patients' recovery progress. The model showed good predictability, with the area under receiver operating characteristic curve of 0.829 in the 10-fold cross-validation and 0.912 in the external validation. The sensitivity/specificity table assists the tradeoff decisions necessary to apply the model in practice. This study moves us closer to the goal of providing lapse prediction so that patients might receive more targeted and timely support. © 2013.

Aligning observed and modelled behaviour based on workflow decomposition

NASA Astrophysics Data System (ADS)

Wang, Lu; Du, YuYue; Liu, Wei

2017-09-01

When business processes are mostly supported by information systems, the availability of event logs generated from these systems, as well as the requirement of appropriate process models are increasing. Business processes can be discovered, monitored and enhanced by extracting process-related information. However, some events cannot be correctly identified because of the explosion of the amount of event logs. Therefore, a new process mining technique is proposed based on a workflow decomposition method in this paper. Petri nets (PNs) are used to describe business processes, and then conformance checking of event logs and process models is investigated. A decomposition approach is proposed to divide large process models and event logs into several separate parts that can be analysed independently; while an alignment approach based on a state equation method in PN theory enhances the performance of conformance checking. Both approaches are implemented in programmable read-only memory (ProM). The correctness and effectiveness of the proposed methods are illustrated through experiments.

Predictive Modeling of Addiction Lapses in a Mobile Health Application

PubMed Central

Chih, Ming-Yuan; Patton, Timothy; McTavish, Fiona M.; Isham, Andrew; Judkins-Fisher, Chris L.; Atwood, Amy K.; Gustafson, David H.

2013-01-01

The chronically relapsing nature of alcoholism leads to substantial personal, family, and societal costs. Addiction-Comprehensive Health Enhancement Support System (A-CHESS) is a smartphone application that aims to reduce relapse. To offer targeted support to patients who are at risk of lapses within the coming week, a Bayesian network model to predict such events was constructed using responses on 2,934 weekly surveys (called the Weekly Check-in) from 152 alcohol-dependent individuals who recently completed residential treatment. The Weekly Check-in is a self-monitoring service, provided in A-CHESS, to track patients’ recovery progress. The model showed good predictability, with the area under receiver operating characteristic curve of 0.829 in the 10-fold cross-validation and 0.912 in the external validation. The sensitivity/specificity table assists the tradeoff decisions necessary to apply the model in practice. This study moves us closer to the goal of providing lapse prediction so that patients might receive more targeted and timely support. PMID:24035143

The current and potential health benefits of the National Health Service Health Check cardiovascular disease prevention programme in England: A microsimulation study

PubMed Central

Jackson, Christopher; Steinacher, Arno; Goodman, Anna; Langenberg, Claudia; Griffin, Simon

2018-01-01

Background The National Health Service (NHS) Health Check programme was introduced in 2009 in England to systematically assess all adults in midlife for cardiovascular disease risk factors. However, its current benefit and impact on health inequalities are unknown. It is also unclear whether feasible changes in how it is delivered could result in increased benefits. It is one of the first such programmes in the world. We sought to estimate the health benefits and effect on inequalities of the current NHS Health Check programme and the impact of making feasible changes to its implementation. Methods and findings We developed a microsimulation model to estimate the health benefits (incident ischaemic heart disease, stroke, dementia, and lung cancer) of the NHS Health Check programme in England. We simulated a population of adults in England aged 40–45 years and followed until age 100 years, using data from the Health Survey of England (2009–2012) and the English Longitudinal Study of Aging (1998–2012), to simulate changes in risk factors for simulated individuals over time. We used recent programme data to describe uptake of NHS Health Checks and of 4 associated interventions (statin medication, antihypertensive medication, smoking cessation, and weight management). Estimates of treatment efficacy and adherence were based on trial data. We estimated the benefits of the current NHS Health Check programme compared to a healthcare system without systematic health checks. This counterfactual scenario models the detection and treatment of risk factors that occur within ‘routine’ primary care. We also explored the impact of making feasible changes to implementation of the programme concerning eligibility, uptake of NHS Health Checks, and uptake of treatments offered through the programme. We estimate that the NHS Health Check programme prevents 390 (95% credible interval 290 to 500) premature deaths before 80 years of age and results in an additional 1,370 (95% credible interval 1,100 to 1,690) people being free of disease (ischaemic heart disease, stroke, dementia, and lung cancer) at age 80 years per million people aged 40–45 years at baseline. Over the life of the cohort (i.e., followed from 40–45 years to 100 years), the changes result in an additional 10,000 (95% credible interval 8,200 to 13,000) quality-adjusted life years (QALYs) and an additional 9,000 (6,900 to 11,300) years of life. This equates to approximately 300 fewer premature deaths and 1,000 more people living free of these diseases each year in England. We estimate that the current programme is increasing QALYs by 3.8 days (95% credible interval 3.0–4.7) per head of population and increasing survival by 3.3 days (2.5–4.1) per head of population over the 60 years of follow-up. The current programme has a greater absolute impact on health for those living in the most deprived areas compared to those living in the least deprived areas (4.4 [2.7–6.5] days of additional quality-adjusted life per head of population versus 2.8 [1.7–4.0] days; 5.1 [3.4–7.1] additional days lived per head of population versus 3.3 [2.1–4.5] days). Making feasible changes to the delivery of the existing programme could result in a sizable increase in the benefit. For example, a strategy that combines extending eligibility to those with preexisting hypertension, extending the upper age of eligibility to 79 years, increasing uptake of health checks by 30%, and increasing treatment rates 2.5-fold amongst eligible patients (i.e., ‘maximum potential’ scenario) results in at least a 3-fold increase in benefits compared to the current programme (1,360 premature deaths versus 390; 5,100 people free of 1 of the 4 diseases versus 1,370; 37,000 additional QALYs versus 10,000; 33,000 additional years of life versus 9,000). Ensuring those who are assessed and eligible for statins receive statins is a particularly important strategy to increase benefits. Estimates of overall benefit are based on current incidence and management, and future declines in disease incidence or improvements in treatment could alter the actual benefits observed in the long run. We have focused on the cardiovascular element of the NHS Health Check programme. Some important noncardiovascular health outcomes (e.g., chronic obstructive pulmonary disease [COPD] prevention from smoking cessation and cancer prevention from weight loss) and other parts of the programme (e.g., brief interventions to reduce harmful alcohol consumption) have not been modelled. Conclusions Our model indicates that the current NHS Health Check programme is contributing to improvements in health and reducing health inequalities. Feasible changes in the organisation of the programme could result in more than a 3-fold increase in health benefits. PMID:29509767

The current and potential health benefits of the National Health Service Health Check cardiovascular disease prevention programme in England: A microsimulation study.

PubMed

Mytton, Oliver T; Jackson, Christopher; Steinacher, Arno; Goodman, Anna; Langenberg, Claudia; Griffin, Simon; Wareham, Nick; Woodcock, James

2018-03-01

The National Health Service (NHS) Health Check programme was introduced in 2009 in England to systematically assess all adults in midlife for cardiovascular disease risk factors. However, its current benefit and impact on health inequalities are unknown. It is also unclear whether feasible changes in how it is delivered could result in increased benefits. It is one of the first such programmes in the world. We sought to estimate the health benefits and effect on inequalities of the current NHS Health Check programme and the impact of making feasible changes to its implementation. We developed a microsimulation model to estimate the health benefits (incident ischaemic heart disease, stroke, dementia, and lung cancer) of the NHS Health Check programme in England. We simulated a population of adults in England aged 40-45 years and followed until age 100 years, using data from the Health Survey of England (2009-2012) and the English Longitudinal Study of Aging (1998-2012), to simulate changes in risk factors for simulated individuals over time. We used recent programme data to describe uptake of NHS Health Checks and of 4 associated interventions (statin medication, antihypertensive medication, smoking cessation, and weight management). Estimates of treatment efficacy and adherence were based on trial data. We estimated the benefits of the current NHS Health Check programme compared to a healthcare system without systematic health checks. This counterfactual scenario models the detection and treatment of risk factors that occur within 'routine' primary care. We also explored the impact of making feasible changes to implementation of the programme concerning eligibility, uptake of NHS Health Checks, and uptake of treatments offered through the programme. We estimate that the NHS Health Check programme prevents 390 (95% credible interval 290 to 500) premature deaths before 80 years of age and results in an additional 1,370 (95% credible interval 1,100 to 1,690) people being free of disease (ischaemic heart disease, stroke, dementia, and lung cancer) at age 80 years per million people aged 40-45 years at baseline. Over the life of the cohort (i.e., followed from 40-45 years to 100 years), the changes result in an additional 10,000 (95% credible interval 8,200 to 13,000) quality-adjusted life years (QALYs) and an additional 9,000 (6,900 to 11,300) years of life. This equates to approximately 300 fewer premature deaths and 1,000 more people living free of these diseases each year in England. We estimate that the current programme is increasing QALYs by 3.8 days (95% credible interval 3.0-4.7) per head of population and increasing survival by 3.3 days (2.5-4.1) per head of population over the 60 years of follow-up. The current programme has a greater absolute impact on health for those living in the most deprived areas compared to those living in the least deprived areas (4.4 [2.7-6.5] days of additional quality-adjusted life per head of population versus 2.8 [1.7-4.0] days; 5.1 [3.4-7.1] additional days lived per head of population versus 3.3 [2.1-4.5] days). Making feasible changes to the delivery of the existing programme could result in a sizable increase in the benefit. For example, a strategy that combines extending eligibility to those with preexisting hypertension, extending the upper age of eligibility to 79 years, increasing uptake of health checks by 30%, and increasing treatment rates 2.5-fold amongst eligible patients (i.e., 'maximum potential' scenario) results in at least a 3-fold increase in benefits compared to the current programme (1,360 premature deaths versus 390; 5,100 people free of 1 of the 4 diseases versus 1,370; 37,000 additional QALYs versus 10,000; 33,000 additional years of life versus 9,000). Ensuring those who are assessed and eligible for statins receive statins is a particularly important strategy to increase benefits. Estimates of overall benefit are based on current incidence and management, and future declines in disease incidence or improvements in treatment could alter the actual benefits observed in the long run. We have focused on the cardiovascular element of the NHS Health Check programme. Some important noncardiovascular health outcomes (e.g., chronic obstructive pulmonary disease [COPD] prevention from smoking cessation and cancer prevention from weight loss) and other parts of the programme (e.g., brief interventions to reduce harmful alcohol consumption) have not been modelled. Our model indicates that the current NHS Health Check programme is contributing to improvements in health and reducing health inequalities. Feasible changes in the organisation of the programme could result in more than a 3-fold increase in health benefits.

Modeling criterion shifts and target checking in prospective memory monitoring.

PubMed

Horn, Sebastian S; Bayen, Ute J

2015-01-01

Event-based prospective memory (PM) involves remembering to perform intended actions after a delay. An important theoretical issue is whether and how people monitor the environment to execute an intended action when a target event occurs. Performing a PM task often increases the latencies in ongoing tasks. However, little is known about the reasons for this cost effect. This study uses diffusion model analysis to decompose monitoring processes in the PM paradigm. Across 4 experiments, performing a PM task increased latencies in an ongoing lexical decision task. A large portion of this effect was explained by consistent increases in boundary separation; additional increases in nondecision time emerged in a nonfocal PM task and explained variance in PM performance (Experiment 1), likely reflecting a target-checking strategy before and after the ongoing decision (Experiment 2). However, we found that possible target-checking strategies may depend on task characteristics. That is, instructional emphasis on the importance of ongoing decisions (Experiment 3) or the use of focal targets (Experiment 4) eliminated the contribution of nondecision time to the cost of PM, but left participants in a mode of increased cautiousness. The modeling thus sheds new light on the cost effect seen in many PM studies and suggests that people approach ongoing activities more cautiously when they need to remember an intended action. PsycINFO Database Record (c) 2015 APA, all rights reserved.

Antimicrobial activity of root canal irrigants against biofilm forming pathogens- An in vitro study

PubMed Central

Ghivari, Sheetal Basavraj; Bhattacharya, Haimanti; Bhat, Kishore G.; Pujar, Madhu A.

2017-01-01

Aims: The aim of the study was to check the antimicrobial activity of the 5% Sodium hypochlorite, 2% Chlorhexidine, 0.10% Octenidine (OCT), and 2% Silver Zeolite (SZ) at different time intervals against a single species biofilm of Enterococcus faecalis, Staphylococcus aureus, and Candida albicans model prepared on a nitrocellulose membrane. Settings and Design: In vitro nitrocellulose biofilm model was used to check antibacterial efficacy of root canal irrigants. Materials and Methods: The in vitro nitrocellulose biofilm model was used to check the antibacterial activity of root canal irrigants. Single species biofilms were suspended into 96-well microtiter plate and treated with root canal irrigants for 1, 5, 10, 15, 30, and 60 s, respectively. The remaining microbial load in the form of colony-forming unit/ml after antimicrobial treatment was tabulated and data were statistically analyzed. Statistical Analysis: SPSS version 17, Kruskal–Wallis ANOVA, Mann–Whitney U-test, and Wilcoxon matched pair test (P < 0.05) were used. Results: All tested microorganisms were eliminated within 30 s by all the antimicrobial substances tested except normal saline. 2% chlorhexidine and 0.10% OCT were equally effective against C. albicans at 30 s. Conclusion: The newly tested irrigants have shown considerable antibacterial activity against selected single species biofilm. OCT (0.10%) can be used as an alternative endodontic irrigant. PMID:29279615

The impact of joint responses of devices in an airport security system.

PubMed

Nie, Xiaofeng; Batta, Rajan; Drury, Colin G; Lin, Li

2009-02-01

In this article, we consider a model for an airport security system in which the declaration of a threat is based on the joint responses of inspection devices. This is in contrast to the typical system in which each check station independently declares a passenger as having a threat or not having a threat. In our framework the declaration of threat/no-threat is based upon the passenger scores at the check stations he/she goes through. To do this we use concepts from classification theory in the field of multivariate statistics analysis and focus on the main objective of minimizing the expected cost of misclassification. The corresponding correct classification and misclassification probabilities can be obtained by using a simulation-based method. After computing the overall false alarm and false clear probabilities, we compare our joint response system with two other independently operated systems. A model that groups passengers in a manner that minimizes the false alarm probability while maintaining the false clear probability within specifications set by a security authority is considered. We also analyze the staffing needs at each check station for such an inspection scheme. An illustrative example is provided along with sensitivity analysis on key model parameters. A discussion is provided on some implementation issues, on the various assumptions made in the analysis, and on potential drawbacks of the approach.

A Hierarchical Modeling Approach to Data Analysis and Study Design in a Multi-Site Experimental fMRI Study

ERIC Educational Resources Information Center

Zhou, Bo; Konstorum, Anna; Duong, Thao; Tieu, Kinh H.; Wells, William M.; Brown, Gregory G.; Stern, Hal S.; Shahbaba, Babak

2013-01-01

We propose a hierarchical Bayesian model for analyzing multi-site experimental fMRI studies. Our method takes the hierarchical structure of the data (subjects are nested within sites, and there are multiple observations per subject) into account and allows for modeling between-site variation. Using posterior predictive model checking and model…

30 CFR 77.902-2 - Approved ground check systems not employing pilot check wires.

Code of Federal Regulations, 2010 CFR

2010-07-01

... pilot check wires. 77.902-2 Section 77.902-2 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION... Approved ground check systems not employing pilot check wires. Ground check systems not employing pilot check wires shall be approved by the Secretary only after it has been determined that the system...

30 CFR 77.902-2 - Approved ground check systems not employing pilot check wires.

Code of Federal Regulations, 2011 CFR

2011-07-01

... pilot check wires. 77.902-2 Section 77.902-2 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION... Approved ground check systems not employing pilot check wires. Ground check systems not employing pilot check wires shall be approved by the Secretary only after it has been determined that the system...

Interface Circuits for Self-Checking Microprocessors

NASA Technical Reports Server (NTRS)

Rennels, D. A.; Chandramouli, R.

1986-01-01

Fault-tolerant-microcomputer concept based on enhancing "simple" computer with redundancy and self-checking logic circuits detect hardware faults. Interface and checking logic and redundant processors confer on 16-bit microcomputer ability to check itself for hardware faults. Checking circuitry also checks itself. Concept of self-checking complementary pairs (SCCP's) employed throughout ICL unit.

30 CFR 77.902-2 - Approved ground check systems not employing pilot check wires.

Code of Federal Regulations, 2012 CFR

2012-07-01

... pilot check wires. 77.902-2 Section 77.902-2 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION... Approved ground check systems not employing pilot check wires. Ground check systems not employing pilot check wires shall be approved by the Secretary only after it has been determined that the system...

30 CFR 77.902-2 - Approved ground check systems not employing pilot check wires.

Code of Federal Regulations, 2013 CFR

2013-07-01

... pilot check wires. 77.902-2 Section 77.902-2 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION... Approved ground check systems not employing pilot check wires. Ground check systems not employing pilot check wires shall be approved by the Secretary only after it has been determined that the system...

30 CFR 77.902-2 - Approved ground check systems not employing pilot check wires.

Code of Federal Regulations, 2014 CFR

2014-07-01

... pilot check wires. 77.902-2 Section 77.902-2 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION... Approved ground check systems not employing pilot check wires. Ground check systems not employing pilot check wires shall be approved by the Secretary only after it has been determined that the system...

Ultrasound use during cardiopulmonary resuscitation is associated with delays in chest compressions.

PubMed

Huis In 't Veld, Maite A; Allison, Michael G; Bostick, David S; Fisher, Kiondra R; Goloubeva, Olga G; Witting, Michael D; Winters, Michael E

2017-10-01

High-quality chest compressions are a critical component of the resuscitation of patients in cardiopulmonary arrest. Point-of-care ultrasound (POCUS) is used frequently during emergency department (ED) resuscitations, but there has been limited research assessing its benefits and harms during the delivery of cardiopulmonary resuscitation (CPR). We hypothesized that use of POCUS during cardiac arrest resuscitation adversely affects high-quality CPR by lengthening the duration of pulse checks beyond the current cardiopulmonary resuscitation guidelines recommendation of 10s. We conducted a prospective cohort study of adults in cardiac arrest treated in an urban ED between August 2015 and September 2016. Resuscitations were recorded using video equipment in designated resuscitation rooms, and the use of POCUS was documented and timed. A linear mixed-effects model was used to estimate the effect of POCUS on pulse check duration. Twenty-three patients were enrolled in our study. The mean duration of pulse checks with POCUS was 21.0s (95% CI, 18-24) compared with 13.0s (95% CI, 12-15) for those without POCUS. POCUS increased the duration of pulse checks and CPR interruption by 8.4s (95% CI, 6.7-10.0 [p<0.0001]). Age, body mass index (BMI), and procedures did not significantly affect the duration of pulse checks. The use of POCUS during cardiac arrest resuscitation was associated with significantly increased duration of pulse checks, nearly doubling the 10-s maximum duration recommended in current guidelines. It is important for acute care providers to pay close attention to the duration of interruptions in the delivery of chest compressions when using POCUS during cardiac arrest resuscitation. Copyright © 2017 Elsevier B.V. All rights reserved.

Access to Employee Wellness Programs and Use of Preventive Care Services Among U.S. Adults.

PubMed

Isehunwa, Oluwaseyi O; Carlton, Erik L; Wang, Yang; Jiang, Yu; Kedia, Satish; Chang, Cyril F; Fijabi, Daniel; Bhuyan, Soumitra S

2017-12-01

There is little research at the national level on access to employee wellness programs and the use of preventive care services. This study examined the use of seven preventive care services among U.S working adults with access to employee wellness programs. The study population comprised 17,699 working adults aged ≥18 years, obtained from the 2015 National Health Interview Survey. Multivariate logistic regression models examined the relationship between access to employee wellness programs and use of seven preventive care services: influenza vaccination, blood pressure check, diabetes check, cholesterol check, Pap smear test, mammogram, and colon cancer screening. Data analysis began in Fall 2016. Overall, 46.6% of working adults reported having access to employee wellness programs in 2015. Working adults with access to employee wellness programs had higher odds of receiving influenza vaccination (OR=1.57, 95% CI=1.43, 1.72, p<0.001), blood pressure check (OR=2.46, 95% CI=2.17, 2.78, p<0.001), diabetes check (OR=1.30, 95% CI=1.12, 1.50, p<0.001), cholesterol check (OR=1.48, 95% CI=1.33, 1.67, p<0.001), and mammogram (OR=1.57, 95% CI=1.24, 1.98, p<0.001). However, there was no significant difference between access to employee wellness programs and the use of Pap smear test and colon cancer screening services. Using a nationally representative sample of individuals, this study found a positive association between access to employee wellness programs and the use of preventive care services. The results support favorable policies to encourage implementing wellness programs in all worksites, especially those with <50 employees. Copyright © 2017 American Journal of Preventive Medicine. Published by Elsevier Inc. All rights reserved.

Providing opportunistic immunisations for at-risk inpatients in a tertiary paediatric hospital.

PubMed

Elia, Sonja; Perrett, Kirsten; Newall, Fiona

2017-01-01

Attaining high immunisation coverage rates for children with medical conditions is vital. The Royal Children's Hospital (RCH) Immunisation Service has the opportunity to check each inpatient's immunisation status and provide opportunistic vaccines and/or bring the Australian Childhood Immunisation Register (ACIR) up-to-date. This paper highlights that during admission, one quarter of children were not up-to-date with routine scheduled immunisations and 42% of those inpatients due or overdue for immunisation were vaccinated. The model of establishing routine checking of immunisation records and reminding hospital staff about immunisation can result in improvements in vaccination coverage. Healthcare providers have a responsibility to check immunisation status and offer vaccines when necessary; however, often there are missed opportunities to immunise. This paper demonstrates that having a dedicated Immunisation Service, a partnership with a relevant government agency, and effective collaboration with inpatient clinical teams, opportunistic immunisation can be achieved for inpatients. © 2017 Wiley Periodicals, Inc.

World energy projection system: Model documentation

NASA Astrophysics Data System (ADS)

1992-06-01

The World Energy Project System (WEPS) is an accounting framework that incorporates projects from independently documented models and assumptions about the future energy intensity of economic activity (ratios of total energy consumption divided by gross domestic product) and about the rate of incremental energy requirements met by hydropower, geothermal, coal, and natural gas to produce projections of world energy consumption published annually by the Energy Information Administration (EIA) in the International Energy Outlook (IEO). Two independently documented models presented in Figure 1, the Oil Market Simulation (OMS) model and the World Integrated Nuclear Evaluation System (WINES), provide projections of oil and nuclear power consumption published in the IEO. Output from a third independently documented model, and the International Coal Trade Model (ICTM), is not published in the IEO but is used in WEPS as a supply check on projections of world coal consumption produced by WEPS and published in the IEO. A WEPS model of natural gas production documented in this report provides the same type of implicit supply check on the WEPS projections of world natural gas consumption published in the IEO. Two additional models are included in Figure 1, the OPEC Capacity model and the Non-OPEC Oil Production model. These WEPS models provide inputs to the OMS model and are documented in this report.

Rural-Urban Differences in Medicare Quality Outcomes and the Impact of Risk Adjustment.

PubMed

Henning-Smith, Carrie; Kozhimannil, Katy; Casey, Michelle; Prasad, Shailendra; Moscovice, Ira

2017-09-01

There has been considerable debate in recent years about whether, and how, to risk-adjust quality measures for sociodemographic characteristics. However, geographic location, especially rurality, has been largely absent from the discussion. To examine differences by rurality in quality outcomes, and the impact of adjustment for individual and community-level sociodemographic characteristics on quality outcomes. The 2012 Medicare Current Beneficiary Survey, Access to Care module, combined with the 2012 County Health Rankings. All data used were publicly available, secondary data. We merged the 2012 Medicare Current Beneficiary Survey data with the 2012 County Health Rankings data using county of residence. We compared 6 unadjusted quality of care measures for Medicare beneficiaries (satisfaction with care, blood pressure checked, cholesterol checked, flu shot receipt, change in health status, and all-cause annual readmission) by rurality (rural noncore, micropolitan, and metropolitan). We then ran nested multivariable logistic regression models to assess the impact of adjusting for community and individual-level sociodemographic characteristics to determine whether these mediate the rurality difference in quality of care. The relationship between rurality and change in health status was mediated by the inclusion of community-level characteristics; however, adjusting for community and individual-level characteristics caused differences by rurality to emerge in 2 of the measures: blood pressure checked and cholesterol checked. For all quality scores, model fit improved after adding community and individual characteristics. Quality is multifaceted and is impacted by individual and community-level socio-demographic characteristics, as well as by geographic location. Current debates about risk-adjustment procedures should take rurality into account.

Assessing neurocognitive function in psychiatric disorders: A roadmap for enhancing consensus

PubMed Central

Ahmari, Susanne E.; Eich, Teal; Cebenoyan, Deniz; Smith, Edward E.; Simpson, H. Blair

2014-01-01

It has been challenging to identify core neurocognitive deficits that are consistent across multiple studies in patients with Obsessive Compulsive Disorder (OCD). In turn, this leads to difficulty in translating findings from human studies into animal models to dissect pathophysiology. In this article, we use primary data from a working memory task in OCD patients to illustrate this issue. Working memory deficiencies have been proposed as an explanatory model for the evolution of checking compulsions in a subset of OCD patients. However, findings have been mixed due to variability in task design, examination of spatial vs. verbal working memory, and heterogeneity in patient populations. Two major questions therefore remain: first, do OCD patients have disturbances in working memory? Second, if there are working memory deficits in OCD, do they cause checking compulsions?. In order to investigate these questions, we tested 19 unmedicated OCD patients and 23 matched healthy controls using a verbal working memory task that has increased difficulty/task-load compared to classic digit-span tasks. OCD patients did not significantly differ in their performance on this task compared to healthy controls, regardless of the outcome measure used (i.e. reaction time or accuracy). Exploratory analyses suggest that a subset of patients with predominant doubt/checking symptoms may have decreased memory confidence despite normal performance on trials with the highest working memory load. These results suggest that other etiologic factors for checking compulsions should be considered. In addition, they serve as a touchstone for discussion, and therefore help us to generate a roadmap for increasing consensus in the assessment of neurocognitive function in psychiatric disorders. PMID:24994503

Body checking and body avoidance in eating disorders: Systematic review and meta-analysis.

PubMed

Nikodijevic, Alexandra; Buck, Kimberly; Fuller-Tyszkiewicz, Matthew; de Paoli, Tara; Krug, Isabel

2018-05-01

This review sought to systematically review and quantify the evidence related to body checking and body avoidance in eating disorders (EDs) to gauge the size of effects, as well as examine potential differences between clinical and nonclinical populations, and between different ED subtypes. PsycINFO, PsycARTICLES, PsycEXTRA, Cochrane Library, and MEDLINE databases were searched for academic literature published until October 2017. A grey literature search was also conducted. Fifty-two studies were identified for the systematic review, of which 34 were eligible for meta-analysis. Only female samples were included in the meta-analysis. ED cases experienced significantly higher body checking (d = 1.26, p < .001) and body avoidance (d = 1.88, p < .001) overall relative to healthy controls, but neither behaviour varied by ED subtype. In nonclinical samples, body checking (r = .60) and body avoidance (r = .56) were significantly correlated with ED pathology (p < .001). These findings support transdiagnostic theoretical models and approaches to ED treatment and early intervention programmes. Copyright © 2018 John Wiley & Sons, Ltd and Eating Disorders Association.

31 CFR 245.8 - Receipt or recovery of original check.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 31 Money and Finance: Treasury 2 2010-07-01 2010-07-01 false Receipt or recovery of original check... CHECKS § 245.8 Receipt or recovery of original check. (a) If the original check is received or recovered... of instructions with respect to the negotiability of such check. (b) If the original check is...

30 CFR 75.902-2 - Approved ground check systems not employing pilot check wires.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 30 Mineral Resources 1 2011-07-01 2011-07-01 false Approved ground check systems not employing pilot check wires. 75.902-2 Section 75.902-2 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION... employing pilot check wires. Ground check systems not employing pilot check wires will be approved only if...

30 CFR 75.902-2 - Approved ground check systems not employing pilot check wires.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Approved ground check systems not employing pilot check wires. 75.902-2 Section 75.902-2 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION... employing pilot check wires. Ground check systems not employing pilot check wires will be approved only if...

POSTERIOR PREDICTIVE MODEL CHECKS FOR DISEASE MAPPING MODELS. (R827257)

EPA Science Inventory

Disease incidence or disease mortality rates for small areas are often displayed on maps. Maps of raw rates, disease counts divided by the total population at risk, have been criticized as unreliable due to non-constant variance associated with heterogeneity in base population si...

The development of a sub-daily gridded rainfall product to improve hydrological predictions in Great Britain

NASA Astrophysics Data System (ADS)

Quinn, Niall; Freer, Jim; Coxon, Gemma; O'Loughlin, Fiachra; Woods, Ross; Liguori, Sara

2015-04-01

In Great Britain and many other regions of the world, flooding resulting from short duration, high intensity rainfall events can lead to significant economic losses and fatalities. At present, such extreme events are often poorly evaluated using hydrological models due, in part, to their rarity and relatively short duration and a lack of appropriate data. Such storm characteristics are not well represented by daily rainfall records currently available using volumetric gauges and/or derived gridded products. This research aims to address this important data gap by developing a sub-daily gridded precipitation product for Great Britain. Our focus is to better understand these storm events and some of the challenges and uncertainties in quantifying such data across catchment scales. Our goal is to both improve such rainfall characterisation and derive an input to drive hydrological model simulations. Our methodology involves the collation, error checking, and spatial interpolation of approximately 2000 rain gauges located across Great Britain, provided by the Scottish Environment Protection Agency (SEPA) and the Environment Agency (EA). Error checking was conducted over the entirety of the TBR data available, utilising a two stage approach. First, rain gauge data at each site were examined independently, with data exceeding reasonable thresholds marked as suspect. Second, potentially erroneous data were marked using a neighbourhood analysis approach whereby measurements at a given gauge were deemed suspect if they did not fall within defined bounds of measurements at neighbouring gauges. A total of eight error checks were conducted. To provide the user with the greatest flexibility possible, the error markers associated with each check have been recorded at every site. This approach aims to enable the user to choose which checks they deem most suitable for a particular application. The quality assured TBR dataset was then spatially interpolated to produce a national scale gridded rainfall product. Finally, radar rainfall data provided by the UK Met Office was assimilated, where available, to provide an optimal hourly estimate of rainfall, given the error variance associated with both datasets. This research introduces a sub-daily rainfall product that will be of particular value to hydrological modellers requiring rainfall inputs at higher temporal resolutions than those currently available nationally. Further research will aim to quantify the uncertainties in the rainfall product in order to improve our ability to diagnose and identify structural errors in hydrological modelling of extreme events. Here we present our initial findings.

Double checking: a second look

PubMed Central

Chreim, Samia; Forster, Alan

2015-01-01

Abstract Rationale, aims and objectives Double checking is a standard practice in many areas of health care, notwithstanding the lack of evidence supporting its efficacy. We ask in this study: ‘How do front line practitioners conceptualize double checking? What are the weaknesses of double checking? What alternate views of double checking could render it a more robust process?’ Method This is part of a larger qualitative study based on 85 semi‐structured interviews of health care practitioners in general internal medicine and obstetrics and neonatology; thematic analysis of the transcribed interviews was undertaken. Inductive and deductive themes are reported. Results Weaknesses in the double checking process include inconsistent conceptualization of double checking, double (or more) checking as a costly and time‐consuming procedure, double checking trusted as an accepted and stand‐alone process, and double checking as preventing reporting of near misses. Alternate views of double checking that would render it a more robust process include recognizing that double checking requires training and a dedicated environment, Introducing automated double checking, and expanding double checking beyond error detection. These results are linked with the concepts of collective efficiency thoroughness trade off (ETTO), an in‐family approach, and resilience. Conclusion(s) Double checking deserves more questioning, as there are limitations to the process. Practitioners could view double checking through alternate lenses, and thus help strengthen this ubiquitous practice that is rarely challenged. PMID:26568537

75 FR 26885 - Airworthiness Directives; Sikorsky Aircraft Corporation Model S-76A, B, and C Helicopters

Federal Register 2010, 2011, 2012, 2013, 2014

2010-05-13

... states that this ``check'' should be performed in accordance with the maintenance manual. Because we have... Airworthiness Directives; Sikorsky Aircraft Corporation Model S- 76A, B, and C Helicopters AGENCY: Federal... directive (AD) for Sikorsky Aircraft Corporation (Sikorsky) Model S-76A, B, and C helicopters that requires...

Late Pleistocene and Holocene paleoclimate and alpine glacier fluctuations recorded by high-resolution grain-size data from an alpine lake sediment core, Wind River Range, Wyoming, USA

NASA Astrophysics Data System (ADS)

Thompson Davis, P.; Machalett, Björn; Gosse, John

2013-04-01

Varved lake sediments, which provide ideal high-resolution climate proxies, are not commonly available in many geographic areas over long time scales. This paper utilizes high-resolution grain-size analyses (n = 1040) from a 520-cm long sediment core from Lower Titcomb Lake (LTL), which lies just outside the type Titcomb Basin (TTB) moraines in the Wind River Range, Wyoming. The TTB moraines lie between Lower Titcomb Lake and Upper Titcomb Lake (UTL), about 3 km beyond, and 200 m lower than the modern glacier margin and Gannett Peak (Little Ice Age) moraines in the basin. Based on cosmogenic exposure dating, the TTB moraines are believed to be Younger Dryas (YD) age (Gosse et al., 1995) and lie in a geomorphic position similar to several other outer cirque moraines throughout the western American Cordillera. Until recently, many of these outer cirque moraines were believed to be Neoglacial age. The sediment core discussed here is one of five obtained from the two Titcomb Lakes, but is by the far the longest with the oldest sediment depositional record. Two AMS radiocarbon ages from the 445- and 455-cm core depths (about 2% loss on ignition, LOI) suggest that the lake basin may have been ice-free as early as 16.1 or even 16.8 cal 14C kyr, consistent with 10Be and 26Al exposure ages from boulders and bedrock surfaces outside the TTB moraines. The 257-cm depth in the core marks an abrupt transition from inorganic, sticky gray silt below (<1% LOI) to more organic, less sticky, light brown silt above (4-10% LOI). Eight AMS radiocarbon ages on bulk sediment and macrofossils date the transition to about 11.6 cal 14C kyr. Thus, sampling resolution above the transition is about 22.57 yr and below the transition is about 12.56 yr, consistent with a decreased sediment accumulation rate in LTL when Younger Dryas ice pulled back from the TTB moraines opening up UTL as a sediment depositional basin. The presented high-resolution grain size record reveals amplitudes and other structural features similar to delta 18O records from deep-lake ostracods in southern Germany, the Greenland ice core record, and speleothems in China. Major increases in the 2 - 8 µm grain size fraction indicative of increased glacier rock flour production between the 257 and 466 cm core depths appear to be roughly correlative with the YD-Alleröd-Bölling-Meiendorf-Heinrich 1 climate events recognized in other terrestrial records and Northern Atlantic Ocean marine cores, but provide much higher resolution than most of those records from a climate-sensitive alpine region in North America.